Coronary tortuosity (C-Tor) is a common finding in coronary angiography (CAG). There are conflicting data about its link to atherosclerosis: one study found a negative relationship with coronary artery disease (CAD), although it had been linked to age and hypertension (HTN), which are CAD risk factors. Carotid intima-media thickness (C-IMT) is a measure of early atherosclerosis and a surrogate for CAD, diastolic dysfunction is also associated with CAD risk factors. In this retrospective case-control study, we investigated the relationship between C-Tor, C-IMT, diastolic dysfunction, and the other risk factors in patients undergoing CAG in a tertiary hospital between July 2017 and June 2018, after excluding patients with significant CAD. C-Tor was defined as the presence of ≥ 3 bends (≥ 45°) along the trunk of at least one main coronary artery in CAG.p < 0.002); other clinical characteristics were similar. The C-IMT was abnormal in the C-Tor group only (p: 0.007). The diastolic dysfunction parameters differed between the two groups: the E/A ratio was < 1 in the C-Tor group and > 1 in the normal group (p: < 0.001); the E velocity and deceleration time were significantly lower in the C-Tor group (p: 0.001 and < 0.001 respectively); the E/E′ ratio, A, and A′ velocities were significantly higher ; while the S′ velocity was similar in the 2 groups (p: 0.078). The C-Tor group had higher total cholesterol and LDL (p: 0.003 and 0.006 respectively). All C-Tor patients undergoing stress tests had positive results. The only independent C-Tor predictors in a regression analysis were HTN, total cholesterol, A-wave velocity, and deceleration time (DT) . A-wave velocity had the best area under the curve, sensitivity, and specificity for C-Tor prediction  followed by DT .After excluding 663 patients due to exclusion criteria, 30 patients with C-Tor were compared with age and gender-matched controls. HTN was significantly more common in the C-Tor group (86.7% vs. 30%, C-Tor is associated with increased C-IMT, HTN, hyperlipidemia, and left ventricular diastolic dysfunction; all contributing to an ongoing atherosclerotic process. A-wave velocity and DT were independent predictors of C-Tor. C-Tor may cause microvascular ischemia that merits further investigation. Coronary artery disease (CAD) is a major cause of mortality and morbidity worldwide , and theCarotid intima-media thickness (C-IMT) has been used as a surrogate for CAD. It signifies early atherosclerosis and smooth muscle proliferation. There is also a graded increase in cardiovascular risk with increasing C-IMT . A C-IMTImpaired left ventricular relaxation—as a function of diastolic dysfunction—is also a frequent finding in echocardiography studies and is associated with advanced age , obesityIn this study, we investigated the interplay between C-Tor, C-IMT, diastolic dysfunction, and the other traditional risk factors of atherosclerosis  in patients with non-significant CAD.This was a retrospective case-control study that included patients who underwent CAG in a tertiary-care hospital between July 2017 and June 2018. Table 2.In all subjects, a fasting blood sample was collected before the CAG for lipid and blood sugar analysis. We defined the clinical risk factors as follows: dyslipidemia: total plasma cholesterol level ≥ 200 mg/dL or a low-density lipoprotein (LDL) cholesterol ≥ 130 mg/dL or on lipid-lowering drugs at the time of the investigation; HTN: systolic blood pressure ≥ 140 mmHg, or diastolic blood pressure ≥ 90 mmHg; or taking antihypertensive medications; DM: fasting plasma glucose ≥ 126 mg/dl, or on anti-diabetic agents. The smoking status was noted: current or ex-smokers versus non-smokers. Obesity was defined as a body mass index ≥ 30 kg/mSelective diagnostic CAG was performed with Judkin’s technique in right/left anterior oblique and anteroposterior views with different cranial and caudal angulations. The main coronary arteries  were tracked. C-Tor was defined as the presence of ≥ 3 bends  in at least one of the main coronary arteries in CAG  Fig. 1)1).Fig. We used the Philips IE 33 ultrasound system  and a 5–10 MHz multi-frequency high-resolution linear transducer to measure the maximum C-IMT from the common carotid artery, with the patient on his back, his neck extended, and his head slightly turned to the opposite side of the carotid artery being examined. A 10-mm longitudinal section was studied at a distance of 1 cm from the carotid bifurcation. The intima-media and the media-adventitia interfaces were measured in the proximal and distal walls in the anterior, lateral, and posterior projections, along an axis perpendicular to the artery. Six measurements were obtained in each carotid artery, to record the maximum. We considered C-IMT ≥ 0.9 mm abnormal  Fig. 2)2).Fig. A standard transthoracic echocardiography study was done on all patients using the same Philips IE 33 ultrasound system, in the left lateral recumbent position during quiet breathing. Pulsed-wave Doppler evaluation of the mitral inflow was acquired in the apical 4 chamber view, with the sample marker at the tips of the mitral valve leaflets. Doppler measurements were averaged over three consecutive cardiac cycles: peak early (E) and late (A) transmitral inflow velocities (in cm/s), the ratio of early to late peak velocities (E/A), and the deceleration time (DT) in ms  t tests were used for comparing continuous variables. Significant variables in the univariate analysis entered a multivariate stepwise logistic regression analysis to detect the independent predictors of C-Tor (outcome).Data analysis was performed using the SPSS 23.0 statistical package for Windows . All continuous variables were normally distributed, so were presented as mean ± standard deviation (SD). Categorical data were presented as numbers (percentages). Chi-square test was used to compare categorical variables while independent p value < 0.05.Then, receiver operating characteristics curve (ROC) analysis was done for the independent variables to derive the cutoff value with maximum sensitivity and specificity. The area under the ROC curve (AUC) was reported as an index of accuracy. In all cases, statistical significance is accepted at a We screened 723 patients undergoing CAG: 663 were excluded based on the exclusion criteria, and 30 patients between July 2015 and June 2016 fulfilling the criteria of C-Tor and were compared with an age and gender-matched control group with normal coronaries during the same period .The baseline clinical and demographic characteristics were similar in the two study groups Table  except HThe C-IMT was significantly higher in the C-Tor group, reaching the cutoff of 9 mm which we considered abnormal. The individual parameters of diastolic dysfunction were significantly different between the two groups: the E velocity and DT were significantly lower in the C-Tor group, while the E/E′ ratio, A, and A′ velocities were significantly higher. The E/A ratio was < 1 in the C-Tor group and > 1 in the normal group. The S′ velocity—which is not a parameter of diastolic function—was similar between the 2 groups Table .Table 3The C-Tor group had higher total cholesterol and LDL, and there was also a trend for higher HDL and triglycerides Table .Table 4A multivariate stepwise regression analysis of the significant variables showed that the only independent predictors of C-Tor were HTN, total cholesterol, A wave velocity, and the DT Table . A wave The key result of our research is that C-IMT, HTN, dyslipidemia, and left ventricular diastolic dysfunction were more prominent in patients with C-Tor than in those without C-Tor.To our knowledge, this is the first study to investigate the relationship between C-IMT and C-Tor. C-IMT is a surrogate of CAD , 26, when = 104), but their study design was not age/gender-matched with a control group. They also did not perform a TDI study—although this proved to be not a significant predictor of C-Tor in our study.C-Tor has also been linked to the changes in the left ventricular geometry—namely concentric hypertrophy , 30. ThiThe association between C-Tor and atherosclerosis has conflicting data. A more recent study  on 367 nThis study was done on elective patients; some of them underwent stress testing before the CAG. All patients with C-Tor who had an earlier stress test showed a positive test result for ischemia while having insignificant CAD. This may denote ischemia at a microvascular level, which suggests that C-Tor is not entirely benign.The mechanism of C-Tor is still not fully understood. It may occur due to reduced axial strain which results in abnormal MMP activity . It can The small sample size of the study cohort is one limitation: the patients were enrolled consecutively within a pre-specified timeframe, but the stringent exclusion criteria, especially the CAD criterion excluded many of them. Invasive imaging of the coronary arteries  would have given a better insight into the coronary vascular structure. Finally, the assessment of the local shear stress created by the C-Tor with the use of a flow dynamic model would be of great value in a better understanding of the underlying pathophysiology.C-Tor is associated with increased C-IMT, HTN, hyperlipidemia, and left ventricular diastolic dysfunction—all contributing to an ongoing atherosclerotic process. A wave velocity and DT were the most significant independent predictors of C-Tor. C-Tor may cause microvascular ischemia, which deserves further investigation.


Bisphenol A (BPA), also known as 2,2,-bis(4-hydroxyphenyl) propane, is a common component of plastics worldwide. However, it has been shown to act as an endocrine disruptor with some hormonal functions. Furthermore, high levels of BPA have been related to the development of cardiovascular events and the activation of carcinogenesis pathways. Patients with chronic kidney disease (CKD) have higher serum concentrations of BPA due to their impaired renal function. This situation is aggravated in CKD patients requiring dialysis, because the BPA content of dialysis devices  is added to the lack of excretion. In addition to the development of BPA-free dialysis filters, some techniques can contribute to the reduction of BPA levels in these patients. The aim of this review is to illustrate the impact of BPA on dialysis patients and suggest some strategies to reduce its inherent risks. Bisphenol A (BPA), also known as 2,2,-bis(4-hydroxyphenyl) propane, is a common component of synthetic polycarbonate plastics and epoxy resins .BPA has been used extensively worldwide in a variety of products, including drink and food containers, glasses, compact discs, electronic devices, and even baby toys or bottles . MedicalDespite its indiscriminate use, BPA is now considered an endocrine disruptor that is able to alter several signalling pathways . Its potInternational campaigns have been conducted in order to reduce or eliminate the BPA content in commonly used products, especially those used by babies or children. The initiative “BPA-free” established a special label to inform customers about the concentration of BPA in plastic containers. Concern about the accumulation of BPA has contributed to the implementation of devices in water treatment plants to reduce its levels . The plastics industry has sought alternatives for avoiding the extensive use of BPA, such as the inclusion of BPA analogues  in the manufacture of different devices. Although, in theory, BPA analogues present a safer profile, some recent studies have demonstrated important toxic events related to their use ,10. HoweThe aim of the present review is to summarise the evidence of kidney-induced BPA injury and the potential for attenuating the accumulation of this compound in dialysis patients.After ingestion, BPA is metabolized in the liver via glucuronidation and sulfation pathways . BPA metabolites are mainly excreted by urine; thus, kidney dysfunction raises their blood levels. Of note, BPA binds with serum albumin up to 75%; this consideration is highly important when analysing its reduction with extra renal techniques . In popuOne of the first declared effects of BPA was hypertension. A randomized crossover clinical trial conducted in elderly adults demonstrated a strong association between drinking canned beverages and blood pressure elevation two hours after intake . This efLinked to vascular damage, BPA is especially toxic for some kidney cells. From a clinical point of view, a recent study conducted by Nie et al. showed that higher BPA levels were significantly associated with the incidence of chronic kidney disease (CKD) . Beyond Interestingly, a recent study performed by Ruiz-Priego et al. showed that BPA could deregulate autophagy and promotes inflammatory infiltration and tubular and renal fibrosis, showing new BPA-mediated damage pathways . A recent meta-analysis conducted by Moreno-Gomez-Toledano et al. summarised all of the published evidence regarding the effects of exposure to BPA on kidney diseases, highlighting its strong association with the incidence of CKD, albuminuria, and glomerular filtration rate .Patients on dialysis are at high risk of developing cardiovascular events, a situation that can be aggravated by BPA. For this reason, it is desirable to reduce BPA levels in this population, especially in patients with comorbidities or in low-income countries where the reuse of filters is still common in clinical practice. The accumulation of BPA in haemodialysis patients is a consequence of kidney impairment and the use of medical devices with BPA-containing plastics, especially filters. It is important to emphasise that not all filters are manufactured with BPA. For example, polysulfone and polyamide membranes show the highest amounts of BPA . In contHaemodialysis techniques have progressed in the last 15 years, improving patients’ survival, as well as their rate of cardiovascular events and quality of life. One of the most relevant advances was the addition of convective solute transport to the diffusive mechanism, which provides a greater reduction of middle-sized molecules (< 50 kDa). The accumulation of those middle-sized molecules, also known as uremic toxins, has been related to worse outcomes, whereas their removal has been associated with important improvements in haemodialysis prognosis . ConsideFinally, the use of BPA analogues, such a BPS, has emerged as an alternative. To date, no dialysis filters have been built using only BPS. However, a recent study by Mas et al. demonstrated that BPS concentrations were 10-fold higher in dialysis patients than in healthy subjects. Interestingly, the exposure of cultured tubular cells to BPS showed no biological effect in terms of cytotoxicity, inflammation, or oxidative stress, thus presenting BPS as an interesting alternative . Although the toxic effect of BPA burden in dialysis patients remains controversial, the mere possibility of enhancing oxidative stress and inflammation in these patients should call the attention of nephrologists. BPA acts as an endocrine disruptor and can enhance cardiovascular risk. In patients with CKD, especially those on dialysis, BPA levels are elevated due to renal impairment. Nephrologists should apply strategies to reduce BPA exposure in order to avoid its deleterious effects.


Despite approximately 95% primary cases of hypertension, secondary hypertension seems to be common with resistant forms. Notably, obstructive sleep apnea (OSA) is known as a common cause of secondary hypertension and has a major characteristic of obesity. Irisin acts as a link between muscles and adipose tissues in obesity, playing an essential role in human blood pressure (BP) regulation. However, whether irisin is associated with secondary hypertension caused by OSA and how it takes effect essentially have not been elucidated.  To investigate the changes of irisin and its relationship with BP in OSA.  72 snoring patients finished Epworth Sleep Scale (ESS) evaluation before polysomnography (PSG). BP was the average of three brachial BP values by mercury sphygmomanometer. Serum irisin level was determined by enzyme-linked immunosorbent assay (ELISA). Results were analyzed by SPSS software. p < 0.05). For BP, significant differences were found between the control group and the other three groups (p < 0.05) and between the quite severe and the other three groups (p ≤ 0.001). Positive correlations were found between irisin and apnea-hypopnea index (AHI), AHI and BP, and irisin level and BP. Negative correlations were between irisin and SpO2 nadir and SpO2 nadir and BP. Positive correlation still existed between AHI and irisin even after adjusting for some obesity-related variables.  Irisin was higher in the severe and quite severe group than that in control and nonsevere groups ( Irisin may serve as a potential biomarker for severity of OSA independently of obesity and imply the development of hypertension. Nowadays, OSA tends to be a growing health concern, and the estimated prevalence ranges from 2% to 14% worldwide . OSA-relAmong them, we put more emphasis on hypertension. It has been widely accepted that there exists a bidirectional association between OSA and hypertension. An increasing number of patients with hypertension suffer from OSA, and meanwhile OSA also exerts an obvious impact on the 24-hour BP circadian pattern related to clinical or subclinical organ damages by hypertension , 6. HoweMany researches have shown that a great number of cytokines are involved in the occurrence and development of OSA . SurprisNevertheless, there remains some controversy whether irisin could promote or prevent the development of hypertension in OSA patients and there were some divergences on the changing trend of irisin levels during the progression of OSA. Therefore, in order to reveal the feature of irisin concentration changes produced by OSA and the impact on the risk of BP, we designed a case-control study to investigate it thoroughly.A total of 72 participants were recruited from those patients who sought medical advice directly or indirectly from the sleep center in the First Hospital of Jilin University with the suspicious diagnosis of OSA. OSA was diagnosed according to the relevant clinical practice guidelines by American Academy of Sleep Medicine (AASM) via overnight polysomnography .All subjects were asked to complete a questionnaire to explore the prior illnesses and drug utilization. We excluded patients who suffered from any infectious disease, cancer, coagulation disorder, and chronic disease including chronic obstructive pulmonary disease, diabetes mellitus, liver cirrhosis, thyroid dysfunction, rheumatoid arthritis, chronic renal failure, psychiatric disorders, and/or sleep disorders other than OSA (upper airway resistance syndrome or narcolepsy). Active use of medications based on physician-adjudicated conditions like vitamins, hormones, immunosuppressants, or free radical scavengers was also the exclusion criteria for this study. The exclusion criteria and assessment protocols were identical for all the studied groups.The study was approved by the Ethics Committee of the First Hospital of Jilin University. All the participants included in the study signed written informed consent/assent forms.All consecutive participants underwent the detailed physical examination and baseline anthropometric measurement in our sleep center, including weight, height, neck circumference (NC), waist circumference (WC), and hip circumference (HC). Body habitus was measured with subjects in light clothing without shoes using standard anthropometric methods. They were all the means of three repetitive measurements.2) was calculated using the formula as follows: body weight (kg) divided by the square of body height (m2).In detail, weight was measured on a balance beam. WC was measured at the level midway between the lower rib margin and the iliac crest at the end of normal expiration. NC was measured with people's head erect and eye facing forward, horizontally at the upper margin of the laryngeal prominence (Adam's apple) , 18. HC Physical activity (PA) was assessed using the self-administered last seven-day recall short version of the International Physical Activity Questionnaire (IPAQ). The amount of PA was expressed in standard metabolic equivalent units (METs) as multiples of resting metabolic rate by minutes of performance during a week –21.ESS was completed prior to PSG to assess daytime sleepiness. It was recorded through an eight-item self-administered score from 0 to 24, and a higher score reflects a higher level of daytime sleepiness.Systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels were assessed in the right arm at the heart level with the patients in the supine position after remaining seated for 5 min of rest in a quiet clinic. BP values were obtained through three systolic and diastolic blood pressure readings taken by Mercury sphygmomanometer. If BP measurements varied by 10 mmHg, an additional measurement was performed. The accumulated measurements were then averaged to determine overall SBP and DBP used for the final analysis. All participants were examined and evaluated by the same researcher.2 nadir from the source. Apnea was defined by the absence of more than or equal to 90% airflow from baseline for over 10 s. Hypopnea was defined as the decrease which is more than or equal to 30% airflow lasting for over 10 s resulting in arousal or oxygen desaturation, a 3% or greater decrease in oxyhemoglobin saturation.Polysomnography was performed for all subjects by Polysomnographic Recording Systems  between 22:00 and 06:00. Oronasal flow, thoracoabdominal movements, electrocardiography, submental and pretibial electromyography, electrooculography, electroencephalography, and transcutaneous measurement of arterial oxygen saturation were recorded, and criteria of AASM were used for scoring the sleep stages. We extracted the SpOAHI was calculated as the number of apneas and hypopneas per hour during sleep time. Owing to the high proportion of severe and quite severe patients visiting our sleep center, according to the traditional classification method the number of patients in severe group did not match up with that in other groups. Hence, we adjusted the division standard to balance the number of groups better and made it beneficial to the result analysis. The patients were divided into four groups according to AHI: control group (AHI < 5 N/h), nonsevere (AHI 5.0–29.9 N/h), severe (AHI 30–59.9 N/h), and quite severe (AHI ≥ 60 N/h) .After overnight polysomnography monitoring, fasting blood samples for each subject were taken in the morning and collected into centrifuge tubes. The samples were centrifuged within 2 h at 1500 rpm for 10 min at 4°C. The obtained plasma was stored at −80°C and was thawed before use. The irisin levels in plasma were measured by using commercially available ELISA kits , and the experiments were carried out based on the manufacturers' instructions. All the samples were tested in duplicate, and the average values were computed. For methodology validation, we evaluated the intra-assay and interassay variability, which were less than 15% for irisin measurement.p value <0.05 was considered to be statistically significant.Subjects' baseline characteristics and serum irisin levels were presented as means ± standard deviations or means with 95% confidence intervals (CIs). Normal distribution was assessed through Shapiro–Wilk test. For the statistical comparisons among four groups, one-way analysis of variance (ANOVA) followed by post hoc contrast for numerical variables and Bonferroni was performed to evaluate the significance of difference between two groups. Correlations between variables and polysomnography parameters were sought by way of the Spearman correlation test. The Spearman correlation coefficients (rho) were used to quantify the correlations between two variables. The statistical analysis was performed with the aid of social sciences (SPSS) software version 23.0. For 95% confidence interval, a two-tailed 2. As shown in p > 0.05). All of weight, BMI, NC, WC, HC, WC/HC, SpO2 nadir, ESS, SBP, and DBP levels differed significantly between the groups .The demographic and clinical characteristics of all 72 subjects are shown in p ≤ 0.001), and SPO2 nadir was lower in the three OSA groups than that in control group. SBP and DBP in quite severe groups are significantly higher than those in the other three groups . ESS score was higher in the two severe OSA groups than that in control group and nonsevere group (p < 0.05). There was no significant difference for physical activity level among all the groups (p > 0.05). More detailed data comparison and analysis are shown in Specifically, NC, WC/HC, BMI, and weight were significantly higher in severe and quite severe OSA groups than those in control group , and it was also higher in severe group (287.17 ± 143.52 ng/ml) than that in control group (p < 0.01). There was no significant difference found between severe group and quite severe group (Serum irisin level was higher in quite severe OSA group (345.74 ± 99.53 ng/ml) than that in control group (140.29 ± 97.72 ng/ml) and that in nonsevere group (201.13 ± 123.91 ng/ml) (control: re group .n = 72), we found that serum irisin level was positively correlated with AHI . In addition, serum irisin levels were correlated positively with ESS and negatively with SpO2 nadir, respectively  .By analyzing the total population of all snoring subjects ( −0.450) . No corrp=0.044, r = 0240; NC controlled: p ≤ 0.001, r = 0.419; WC/HC controlled: p=0.026, r = 0.280). Considering the significant difference of age among groups (p=0.012), we adjusted the factor of age and still found the important difference between serum irisin level and AHI .BMI, NC, and WC/HC were also associated with serum irisin level. When adjusted for these factors, serum irisin level is still positively correlated with AHI , suggesting that serum irisin levels were associated with the increasing BP. Additionally, both ESS score and SpO2 nadir correlated significantly with the BP  (As was shown in  −0.506) .2 nadir, SBP, and DBP . It is noted that the BMI of their OSA group ranges from 21.8 to 25.6. Nevertheless, obesity is the most important risk factor for OSA; at least 70% of patients are obese [As was mentioned above, in the obese or overweight state, the massive secretion directly or indirectly by adipocytes was mainly responsible for the considerable irisin increase. However, under nonobese conditions, the muscle cells take the lead in regulating the high level of circulating irisin . It may f irisin . In addif irisin , which sre obese . Hence, 2 nadir was related to AHI and irisin, which means that SpO2 nadir may be regarded as intermediate pathway to connect AHI and irisin. It is reported that irisin expression is triggered by hypoxia-induced sympathetic activation and involved in activation of inflammatory cascades in various organs [2 nadir or hypoxic burden after adjustments of obesity-related variables has yet to be investigated deeply. In a word, we have discussed the potential of irisin in OSA and found that irisin could regulate muscle growth [Meanwhile, it could be discovered in our results that SpOs organs –42. Alsos organs –45. As fe growth  and metae growth , 47, 48.Some previous studies indicated that higher circulating irisin levels were related to a variety of cardiovascular diseases (CVD), like vascular atherosclerosis and ischemic stroke, suggesting that elevated circulating irisin levels could be a sign of vascular structural or functional changes and adverse cardiovascular events –52. As nOur study has some limitations that should be considered when interpreting the results: first, our cohort sample size was relatively limited and larger study cohorts are needed in the future. Second, BMI was used to assess our study population as a good method but it cannot differentiate between body fat and lean body mass. And the long-term physical activity status of subjects was not evaluated. Finally, many questions have been raised with regard to the molecular regulatory pathways involved in the correlation between irisin level, AHI, and BP. Although whether these influences of OSA are sufficient, independently of obesity, to contribute significantly to the “hypertension” remains unsettled, irisin would still be an attractive tool for treating or intervening hypertension and OSA considering its relationship with human adipocytes, myocytes, and cardiovascular system.To summarize, this paper indicates that circulating irisin has the potential implication as a diagnostic biomarker for monitoring and predicting the occurrence and progression of BP increase in OSA patients. However, further studies are required to determine the molecular mechanism of irisin acting on OSA to make it a better therapeutic agent to combat cardiovascular diseases, especially hypertension.


Either high or low values of adenosine blood level (ABL) can differentiate some forms of neurally mediated syncope (NMS). A rapid method of measurement has recently been developed. The aim of the present study was: (1) to compare ABLs in an unselected population of consecutive patients referred for evaluation of suspected NMS syncope and in healthy controls; and (2) to assess the relative prevalence of low and high adenosine forms among an unselected syncope population.Whole blood was collected after finger puncture, blood being deposit on a blot paper and adenosine concentration was measured by liquid chromatography/mass spectrometry (LC-MS/MS).p = 0.04)] and a larger distribution of values. Low ABL values below the 5th percentile were observed in 28 (19%) patients, and, in five controls, p = 0.003 and high ABL values were observed in 26 (18%) patients and five controls, p = 0.009.Among 89 control subjects, the median ABL value was 0.54 μM . The lowest 5% and the upper 95% percentile were 0.40 and 0.80 μM, respectively. Compared with healthy subjects, the 146 patients with syncope showed, on average, a higher median ABL value [0.63 (IQR 0.45–0.73, ABL is different in patients with suspected NMS than in healthy subjects. Patients with low and high adenosine values account for 19% and 18% of the general population. Thus, low and high ABL limits, as defined in this study, may help to define the purinergic profile of unselected subjects with a clinical diagnosis of suspected NMS. The effects of adenosine on A1 R leads to bradycardia, sinus arrest or atrio-ventricular block (2A receptors (A2AR) that are in the vessels and which cause vasodilation  and neurally mediated syncope (NMS) . Among tar block , 4. ConvThe prevalence of patients with low and high adenosine syncope is uncertain because, until now, adenosine has been studied in small, selected populations. A barrier to the widespread evaluation of adenosine in clinical practice has been the difficulty of obtaining rapid reliable measures. Indeed, owing to its short half-life in the blood, adenosine is not easy to sample and measure. At the time of venepuncture, a stop solution – not commercially available - must be utilized to inhibit the degradation of adenosine in body fluid. After plasma deproteinization, adenosine concentration is evaluated by means of high-performance liquid chromatography. A rapid method (“blot spot”) has recently been developed and assessed in a small population . It consThe aim of the present study was: (1) to compare ABLs in an unselected population of subjects with a history of suspected NMS and in healthy controls; and (2) to assess the relative prevalence of low and high adenosine forms among this population.We assessed the rapid method of adenosine dosage in whole blood using Liquid Chromatography, Mass Spectrometry (LC-MS/MS)  in unselThe Syncope group was formed by patients aged >14 years referred to the syncope clinic of Istituto Auxologico Italiano, Milan, Italy because affected by one or more episodes of unexplained syncope to confirm or reject the clinical suspicion of NMS after exclusion of competing diagnoses. In particular, according to the diagnostic criteria of ESC guidelines , the patThe day of blood sampling, the participants were allowed to take their usual drug therapies and had no dietary restrictions. Whole blood was collected using finger puncture, while the patient was sitting in a quiet environment, followed by deposit of a drop of blood (20 μL) on a blotting paper (Whatman 903 protein saver cards™) and dried overnight at room temperature to obtain dried blood spot. Then, the blot spots were stored at room temperature and shipped to the Laboratory of Biochemistry of Timone Hospital for analysis.The method has been previously described . BrieflyAfter the extraction, adenosine concentration was measured by LC-MS/MS. Samples were analyzed using a Shimadzu UFLC XR system . The LC system was interfaced with an ABSciex 4,500 triple quadrupole mass spectrometer , operating with an electrospray ionization source (ESI) using nitrogen (purity: 99.99%). Ten microliters of the extracted sample were injected onto a 2.1-mm- × -100-mm, 3-μm Atlantis R T3 column, Waters . The starting mobile phase consisted of 3% methanol and 97% acidified water (0.1% formic acid), with a flow of 0.7 ml/min for 3.5 min. Then, the gradient of methanol was increased to 30% for 3 min. The column was re-equilibrated for 2 min to starting conditions.ABL values were reported as median and interquartile range [IQR] and compared between groups by means of Mann–Whitney non-parametric test. Categorical variables were shown as absolute and relative frequencies and compared between groups by means of the Fisher exact test or Chi-squared test for a trend as appropriate.The study population consisted of 146 patients with a diagnosis of likely neurally mediated syncope; their mean age was 57 ± 20 years, 67 were males (46%). The clinical features of patients with syncope were consistent with those of an unselected general population: 108 had prodromes, suggesting an autonomic activation, 54 had recognizable triggers ; 55 were taking antihypertensive drugs. HUTT was positive in 101 (72%) patients (vasodepressor or mixed in 88 and cardioinhibitory in 13) and negative in 45 (28%) patients. The control group consisted of 89 healthy volunteers; their mean age was 51 ± 18 years, 46 were males (52%).p = 0.04)] and a larger distribution of values  patients and five controls, p = 0.009.In controls, the average median ABL value was 0.54 μM . The lowest 5th and the highest 95th percentiles were 0.40 μM and 0.80 μM, respectively; these values were, therefore, considered as the normal limit for low ABL and high ABL in patients with syncope. f values . The lowThus, the phenotype of low adenosine syncope could be identified in 19% and that of high adenosine syncope in 18% of the whole syncope population . The cliThe main findings of the study are that rest ABL, measured with the rapid “blot spot” method on whole blood, can distinguish a general population of patients with suspected NMS from healthy subjects. Among an unselected NMS population, two groups of patients with low and high outlier ABL values can be identified, which account for 19% and 18% of the population, respectively. These results are consistent with those of previous studies performed with the standard method of high-performance liquid chromatography in plasma with stop solution , 4, 8, 9th percentile of healthy subjects and that several patients with positive vasovagal response during tilt testing had values above the 95th percentile of healthy subjects. The result of the present study shows that such correlation is more difficult to be found in an unselected general population. In a recent trial  for rapid, easy-to-perform, and cheap measurement of adenosine in the whole blood. The low and high ABL limits, as defined in this study, may help to define the purinergic profile of patients affected by NMS and can be used in future studies. Because the expression level of adenosine receptor is also crucial to interpret the relationship between the adenosinergic system and NHS, further studies are necessary to explore notably the ratio AMany subjects with NMS were on antihypertensive treatment, which can modify plasma adenosine values. In previous studies, antihypertensive therapy was stopped at the time of adenosine blood sampling , 11, 12.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. The patients/participants provided their written informed consent to participate in this study.AG: conceptualization, investigation, data curation, methodology, writing–original draft, and writing-review and editing. MB: conceptualization, formal analysis, methodology, writing–original draft, and writing-review and editing. MC and MG: adenosine measurement. FE: data collection. JD and GP: investigation and writing–review and editing. RG: conceptualization, investigation, and writing–review and editing. All authors contributed to the article and approved the submitted version.This work was supported by Amidex Méditerranée Foundation and Aix Marseille University.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


In the 43 patients, false alarms were detected in 7 patients with capnography and 11 patients with nasal pressure monitoring (p = 0.427). Harmful events unrelated to nasal pressure monitoring occurred in 2 patients. Nasal pressure monitoring is safe and possibly useful for respiratory monitoring despite false alarms during sedation.Nasal pressure signal is commonly used to evaluate obstructive sleep apnea. This study aimed to assess its safety for respiratory monitoring during sedation. A total of 45 adult patients undergoing sedation with propofol and fentanyl for invasive endoscopic procedures were enrolled. While both nasal pressure and capnograph signals were continuously recorded, only the nasal pressure signal was displayed. The primary outcome was the incidence of oxygen desaturation below 90%. The secondary outcomes were the ability to predict the desaturation and incidence of harmful events and false alarms, defined as an apnea waveform lasting more than 3 min without desaturation. Of the 45 participants, 43 completed the study. At least one desaturation event occurred in 12 patients . In these 12 patients, more than half of the desaturation events were predictable in 9 patients by capnography and 11 patients by nasal pressure monitoring ( Even tracheal intubation (0.09%) and death (0.03%) have occurred in some cases where propofol was used for sedation in endoscopy2. Therefore, appropriate use of cardiorespiratory monitoring is recommended during and after endoscopy with sedation.The upper interventional endoscopy procedures of endoscopic submucosal dissection (ESD), endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), and double-balloon enteroscopy (DBE) are currently performed under sedation with sedative agents, including propofol, dexmedetomidine, and benzodiazepine, and analgesics, including fentanyl, pentazocine, and pethidine, to reduce patient distress and achieve successful completion. However, hypoxemia associated with respiratory depression or hemodynamic instability is well known to occur frequently during sedation. Furthermore, cardiopulmonary events during endoscopy are described to be the most important fatal complications3. Furthermore, the American Society for Gastrointestinal Endoscopy suggested that capnography be considered for patients undergoing endoscopy targeting deep sedation4. Therefore, capnography during an endoscopic procedure with deep sedation has been recommended in Japan5. However, capnography does not precisely characterize the nature of breathing because end-tidal carbon dioxide is an indirect and lagging indicator of respiratory status rather than a direct measurement of changes in respiratory volume7. Clinical trials comparing capnography with standard monitoring have reported controversial results17. Therefore, the use of capnography has not been established as a recognized standard for respiratory monitoring due to other factors, including cost, false alarms, and sensitivity to respiratory abnormalities18. A recent study revealed that approximately 50% of episodes with oxygen desaturation or hypoxemia occurred in the absence of capnography-observed apnea-altered ventilation16.The European Society of Gastrointestinal Endoscopy recommended that capnography be considered during the administration of propofol in specific situations, including high-risk patients, intended deep sedation, and long procedure duration20. The waveform of a nasal pressure monitor is comparable in shape and amplitude to that of a pneumotachograph and provides a semiquantitative estimation of airflow21. Hypopnea can be judged more easily using this monitoring method because its wave amplitude changes dynamically and can be interpreted as changes in breathing depth. Furthermore, the use of a nasal pressure monitor has been reported to be useful for detecting airway obstruction, and a characteristic flattened waveform is indicative of upper airway resistance and inspiratory flow limitation19.A nasal pressure monitor is a simple and easy-to-use tool for assessing airflow and is commonly used during polysomnography, whereas a pneumotachograph, the gold standard method for measuring airflow, is inconvenient for use in daily clinical practice due to the requirement for a well-fitting mask21. Additionally, nasal pressure monitoring is recommended over capnography by the American Academy of Sleep Medicine for sleep apnea testing19. It has been also reported to detect respiratory abnormalities with increased sensitivity and earlier than pulse oximetry in a previous study22. Thus, we hypothesized that the nasal pressure monitor could provide an early warning for appropriate interventions, thereby preventing hypoxemia during sedation. If this hypothesis is correct, a nasal pressure monitor should be non-inferior to capnography in preventing the incidence of hypoxemic events, defined as a decrease in peripheral capillary oxygen saturation (SpO2) below 90%, during sedation. Thus, a prospective, randomized, non-inferiority, phase II and phase III trial was designed to test this hypothesis. This phase II trial aimed to ensure that the nasal pressure monitor can be used as a respiratory monitor during invasive endoscopic procedures under sedation with propofol and that there are no safety concerns. The waveforms of the nasal pressure monitor and capnography were also compared to help understand their characteristics.For these reasons, a nasal pressure monitor can distinguish between the central respiratory disorder due to drug overdose and the airway obstruction that requires management by its waveform2 ≥ 95% on room air, systolic blood pressure ≥ 90 mmHg, and ability to provide written informed consent. The exclusion criteria included regular use of opioids or benzodiazepines for purposes other than sleeping; participation in another clinical trial within 4 weeks of registering for this trial; drug abuse or a physical, mental, or social condition that made enrollment or evaluation impossible; severe cardiac disorder; heart rate < 50 bpm; ASA physical status classification IV or V; severe thyroid disease; pregnancy or lactation; possibility of allergic reaction to propofol or fentanyl; and any other condition that could impair the patient’s safety or might limit the ability of the patient to comply with the protocol.Patients scheduled for ERCP, ESD, EUS-FNA, or DBE under sedation at Chiba University Hospital between December 2019 and April 2020 were enrolled. The inclusion criteria included age ≥ 20 years, SpOAll cases were registered centrally at the data center . All data were collected using case report forms (CRFs), and all CRFs were submitted to the data center. The data center used a system with which it was possible to acquire access logs and validation, enter the CRF data, and create data sets. The database was locked after verification by the principal investigator. This study was approved by the Research Ethics Committee of the Graduate School of Medicine, Chiba University . This trial was registered in the Japan Registry of Clinical Trials (identifier jRCTs032190146) on November 29, 2019. All methods were performed in accordance with the relevant guidelines and regulations of the Declaration of Helsinki. Written informed consent was obtained from all participants.2 Sensor Kit TG-920P; Nihon Kohden Corp., Tokyo, Japan) and the intranasal pressure sensor  were attached to the nose by the sedation doctor. Before sedation, the capnography waveform was configured not to be displayed on the monitor screen , so only the nasal pressure monitor was used as a respiratory monitor. The waveforms were continuously recorded with the monitoring device for later playback and review.This was a prospective, single-center, single-arm phase II trial to confirm the safety of the nasal pressure monitor as a novel approach to monitoring during invasive endoscopic procedures with non-anesthesiologist administration of propofol and fentanyl sedation. All patients were placed in the treatment position after both the capnography sensor  was considered significant using the Bonferroni correction. When comparing respiratory abnormalities, a p-value < 0.0125 was set as the significance level because there were four variables. All data analyses were performed using SAS .This study was approved by the Research Ethics Committee of the Graduate School of Medicine, Chiba University . Written informed consent was obtained from all participants.A total of 45 adult patients were assessed for eligibility, and all the patients were enrolled. Of the 45 patients, two patients dropped out before treatment: one had the procedure canceled, and the other’s respiratory waveform was not displayed from the start due to an equipment malfunction. Thus, we analyzed data from both monitoring waveforms during the treatment of 43 patients. Figure Among the 45 patients, 29 were males, and 16 were females, aged 28–88 years. For 47 procedures, ESD was performed in 5 patients, ERCP in 28, EUS-FNA in 12, and DBE in 2. For one patient who had both DBE and ERCP and three patients who had both EUS-FNA and ERCP, two procedures were performed in the same operative session. All these procedures were performed in one session with a single continuous sedation. Additional baseline characteristics for the study population are shown in Table 2 < 90%  15.3–43.7%). The mean time of SpO2 < 90% for those 12 patients was 98 s (interquartile range 9–107), and the minimum value of SpO2 was 75%. To restore SpO2, we performed an increase in oxygen flow rate in 10 cases, a chin-lift or jaw-thrust maneuver in 8 cases, patient stimulation in 6 cases, and drug infusion cessation in 2 cases, while SpO2 was restored without any treatment in 2 cases. No patient required nasopharyngeal tube insertion or tracheal intubation and was forced to discontinue endoscopic treatment.Of the 43 patients who underwent endoscopic treatment, 12 patients had oxygen desaturation of SpOTable 2 < 90%. On univariate analysis, allergies (p = 0.0234) and American Society of Anesthesiologists (ASA) class I (p = 0.0037) were risk factors for oxygen desaturation during treatment. No patient had ASA class ≥ III. Multivariate analysis was not performed due to the small population size in the hypoxic group.Table 2 < 90% occurred in 12 patients. Respiratory abnormalities were detected in ≥ 50% of the desaturation events in 9 (75.0%) patients with capnography and 11 (91.7%) patients with nasal pressure monitoring  0.29; 95% CI 0.004–4.31). Respiratory abnormality detectability was acceptably high for both respiratory monitoring systems and did not differ between the monitors.During treatment, oxygen desaturation of SpOp = 0.427, OR 0.57; 95% CI 0.17–1.84). False alarms were often detected more than once in the same patient: 11 times with capnography versus 19 times with nasal pressure monitoring. Details of the false alarms are shown in Table Of the 43 patients who underwent endoscopic treatment, false alarms were detected in 7 (16.3%) patients with capnography and 11 (25.6%) patients with nasal pressure monitoring  under propofol-based sedation.In this phase II study, no major safety issues were observed with the nasal pressure monitor as a novel approach to monitoring during invasive endoscopic procedures under sedation with propofol and fentanyl. SpO2 drops. This study may be meaningful in that both the capnography sensor and the intranasal pressure sensor were attached to the same patients during the same procedure. During treatment, only the nasal pressure monitor waveform could be referenced. Therefore, it may not be possible to compare the two monitors fairly. However, we could compare the waveforms of the two monitors with the same timing. Therefore, the characteristics of each monitor could be known. As shown in the representative examples, combining the information from both monitors might lead to a better understanding.Of the 45 patients, two cases dropped out: one due to the cancellation of the endoscopic procedure itself and the other due to the non-display of the monitor due to the occlusion of the cannula by the patient’s body, causing inhibition of pressure transmission. No similar event had occurred since then by taking care not to press the cannula. Two adverse events clearly related to endoscopic procedures were observed, but they had no effect on the primary goal of this phase II study, that is, confirming the safety of nasal pressure monitoring. Furthermore, waveform analysis revealed that the nasal pressure monitoring system could detect respiratory abnormalities when oxygen desaturation episodes occurred. Therefore, nasal pressure monitoring can be used as a respiratory monitor during the endoscopic procedure under sedation to detect respiratory abnormalities before SpO31. Regarding false alarms, which were uniquely defined in this study, there were more false alarms with the nasal pressure monitor than with capnography. However, no significant differences were observed between the two monitors in this population. One possibility is that nasal airway obstruction was caused by endoscopy, which impeded nasal breathing and made oral breathing in which there was insufficient intranasal pressure.According to waveform analysis, there were more patients with high detectability of respiratory abnormalities at oxygen desaturation by the nasal pressure monitor than by capnography. However, no significant differences were observed. As previously reported, even if capnography did not display respiratory abnormalities, hypoxic events occurred in this study. The nasal pressure monitor also could not detect respiratory abnormalities before all hypoxic eventsThis study also thoroughly examined respiratory abnormalities during oxygen deficiency, demonstrating that only the nasal pressure monitor could detect obstructive disorders, which capnography did not Table . However2 < 90%, although ASA class > II was reported to be a risk factor for developing sedation-associated complications32. Confounding factors should have an impact, but a multivariate analysis was not performed due to the small population size. Because determining the risk factors for SpO2 decrease was not the primary goal of this study, a larger sample size is needed to evaluate the risk factors.In this study, ASA class I and allergies were risk factors associated with a decrease in SpO33, we used both drugs for sedation in this study. The sedation with propofol alone adopted in many other countries might lead to different results. Furthermore, apnea > 3 min without oxygen desaturation was used as the definition of false alarm events. However, literature described shorter durations of apneas without desaturation, as presented in Fig. This study has several limitations. First, this was a single-center study conducted at Chiba University. Second, waveform analysis may be biased due to physician subjectivity, even though waveform analysis was performed by three physicians, one of whom was an expert in waveform analysis, and each respiratory abnormality was defined in detail. Third, a waveform analyst examined respiratory abnormalities at the point of oxygen desaturation a few weeks after the procedure to compare the two monitoring systems, even though it is critical that the physician in charge of sedation be able to make a decision regarding respiratory abnormalities during the procedure. This point should be investigated further in future research. Fourth, since the trial was planned as a phase II pilot trial to evaluate the safety and feasibility of nasal pressure monitoring compared to capnography, sample size and event size were low even though the statistically demanded size was reached. Therefore, the study was underpowered to find differences in hypoxic event rates and false alarms for nasal pressure monitoring and capnography. Fifth, since the Japanese guidelines for sedation in gastroenterological endoscopy describe the effectiveness of the combined use of propofol and fentanyl for ERCP2 drops.In conclusion, this study confirmed the safety of the nasal pressure monitor to proceed to a phase III trial. This monitoring method during an endoscopic procedure that requires sedation may be useful in detecting respiratory abnormalities before SpOSupplementary Information 2.Supplementary Information 1.


Background: The association of chronic heart failure (CHF) and iron deficiency (ID) with or without anemia is frequently encountered in current medical practice and has a negative prognostic impact, worsening patients’ exercise capacity and increasing hospitalization costs. Moreover, anemia is common in patients with chronic kidney disease (CKD) and CHF, an association known as cardio-renal anemia syndrome (CRAS) possessing a significantly increased risk of death. Aim: This review aims to provide an illustrative survey on the impact of ID in CHF patients—based on physiopathological traits, clinical features, and the correlation between functional and absolute ID with CHF—and the benefit of iron supplementation in CHF. Method: We selected the most recent publications with important scientific content covering the association of CHF and ID with or without anemia. Discussions: An intricate physiopathological interplay is described in these patients—decrease in erythropoietin levels, activation of the renin-angiotensin-aldosterone system, systemic inflammation, and increases in hepcidin levels. These mechanisms amplify anemia, CHF, and CKD severity and worsen patients’ outcomes. Conclusions: Anemia is frequently encountered in CHF and represents a negative prognostic factor. Data from randomized controlled trials have underlined the administration of intravenous iron therapy  as the only viable treatment option, with beneficial effects on quality of life and exercise capacity in patients with ID and systolic heart failure. Tissue metabolism and many critical biochemical pathways involve the essential trace element iron. The primary consumer of iron is the erythroid bone marrow, which uses it to form new red blood cells. Iron is one of the key elements regarding oxygen homeostasis, including oxygen transport and storage processes ,2.Chronic heart failure (CHF) is a commonly encountered disease, with a prevalence of more than 64 million cases worldwide. Patients suffering from this affliction need continuous medical care, including frequent medical monitoring, hospitalizations, and extensive treatment. Thus, CHF is an economic burden for medical systems all around the globe, with a worldwide expenditure predicted to reach USD 400 billion by 2030 ..32].Heart failure has been associated with a systemic pro-inflammatory status that leads to functional ID. The pro-inflammatory group and the association of bacterial proliferation favor the sequestration of iron in stores by increasing the level of hepcidin, thus decreasing the iron availability for hematopoiesis ,31.Anemia is a common condition in both CHF and CKD. The three entities form a pathological triangle, potentiating the other entities and aggravating patient outcomes  33]..33].The renal synthesis of EPO is stimulated by tissue hypoxia. In CHF, plasma levels of EPO increase when the hemoglobin value decreases, but not proportionally. It has also been highlighted that the bone marrow develops a certain degree of resistance to the action of EPO. However, the most critical alteration in EPO’s activity is CKD, an affliction frequently associated with CHF. Long-term renal ischemia and CKD directly reduce the secretion of EPO . AccordiThe decrease in serum levels of EPO in CHF is also correlated with the excessive secretion of cytokines . These cytokines interfere with EPO’s action, reducing iron availability by inhibiting absorption at the gastrointestinal level and blocking it in the reticuloendothelial system .ACE inhibitors and angiotensin receptor blockers (ARBs), therapeutical agents often used in CHF treatment, inhibit erythroid precursors . One of The effect of ACEIs on erythrocyte formation in patients with heart failure was evaluated in clinical trials, which compared randomized groups using enalapril and placebo, respectively, with the results supporting a higher incidence of anemia in patients being treated with seemingly a dose-dependent effect ,38.Angiotensin II is responsible for vasoconstriction as a direct response to the hemodynamic modifications generated by CHF. A decrease is followed by vasoconstriction in renal perfusion and increases in renin production. Renin transforms angiotensinogen into angiotensin, thus perpetuating a vicious circle and accentuating organ dysfunction. The renin-angiotensin-aldosterone system generates hemodilution through hydrosaline retention, another known causal factor of anemia in patients with heart failure .Renal hypoperfusion caused by CHF determines kidney injury. Decreases in cardiac output, renal blood flow, efferent arteriole vasoconstriction, and neurohormonal activation are followed by changes in intrarenal circulation and increased sodium and water reabsorption. Central venous pressure and its expression in the renal veins lead to a decrease in the glomerular filtration rate, with consequent worsening of renal dysfunction. Increased levels of renin, angiotensin, and aldosterone cause damage directly to cardiac cells, thus exacerbating existing damage. Low renal blood flow also causes an increase in antidiuretic hormone secretion, exacerbating renal vasoconstriction and sodium and water retention .There is a relatively high rate of underdiagnosis of ID because anemia is often not clinically evident. Furthermore, anemia may be completely absent, as it needs a specific time frame to develop after the appearance of ID. In a study by Martens, ID was present in 53% of patients and more frequent in patients with reduced ejection fraction. At the same time, anemia was present in a smaller number of cases: 36% .Diagnostic criteria for ID in CHF patients, with or without anemia, refer to serum ferritin <100 µg/L, or ferritin between 100 µg/L and 299 µg/L, and transferrin saturation <20% .Routinely screening for ID in the entire population of patients with cardiac disease is highly recommended, considering ID’s prevalence among the general demographic and its significant implications for the prognostics of a patient suffering from CHF .According to the literature, ID has been correlated with various clinical consequences only in the presence of anemia. However, recent studies have shown that ID may be an independent predictor of adverse outcomes in patients with systolic heart failure . MoreoveID caused an increase in the length of hospitalization in patients with heart failure . The assID also has a negative impact on exercise capacity in heart failure patients, based on the fact that non-hematopoietic tissues, including skeletal and cardiac muscle tissue, depend on the presence of iron as a critical element in the constitution of proteins involved in vital cellular processes, namely oxygen storage (a component of myoglobin) and oxidative energy metabolism methods (part of oxidative enzymes) ,46,47.ID has been highlighted in clinical trials as an independent factor correlated with increased morbidity and mortality in patients diagnosed with heart failure without the mandatory association of anemia ,48.The 2016 European Society of Cardiology (ESC) guidelines for heart failure address the clear benefit of treating ID in patients with heart failure, where ID is defined as an essential entity independent of the presence of anemia .Treatment options for correcting iron deficiency in the general population are intravenous (IV) or oral iron. In patients with heart failure with low ejection fraction (LVEF), however, the 2016 ESC guidelines specifically recommended that ID should be treated by prescribing iron compounds with parenteral administration, such as IV ferric carboxymaltose , as oralThe efficacy of ferric carboxymaltose has been evaluated in several randomized clinical trials. In 2012, Avni et al.  publisheAnother meta-analysis by Qian et al., which included studies on 907 patients who received intravenous iron-ferric carboxymaltose treatment, confirmed a decrease in the number of hospitalizations of CHF patients .In 2015, the multicenter placebo-controlled CONFIRM-HF study, which enrolled 304 symptomatic ambulatory HF patients with LVEF ≤45% and ID and is the study with the most extended published follow-up period in patients treated with iron (52 weeks), revealed significant NYHA class improvements and quality of life improvement, statistically reported after 24 weeks of treatment. At the same time, IV iron treatment reduced the need for hospitalization in the studied patients .In 2015, a study performed by Toblli et al., after six months of IV iron administration, revealed an improvement in the function of the left ventricle correlated with the reduction in ID, the decrease in inflammatory markers, and the remission of symptoms, as well as the improvement of kidney function, with an increase in glomerular filtration rate .A recent 2018 meta-analysis of individual patient data by Anker et al. proved a reduction in recurrent hospitalizations and cardiovascular mortality in patients with CHF and ID treated with IV ferric carboxymaltose .However, these clinical trials did not evaluate the effect of treatment on survival, so, to date, the potential efficacy of IV iron therapy has not been evaluated in terms of mortality reduction in patients with CHF. Moreover, the effectiveness and safety of intravenous ferric carboxymaltose treatment have not been established yet in acute heart failure or heart failure with preserved ejection fraction (LVEF ≥ 50%), requiring further investigation in more extensive future studies ,59.Although these findings related to iron carboxymaltose therapy should be confirmed by extensive clinical trials, diagnosis and treatment of ID to improve exercise capacity, symptoms, and quality of life will remain an essential part of an optimal approach to CHF.The use of IV ferric carboxymaltose in patients with ID and CHF is restricted in patients with contraindications, such as hypersensitivity to the active substance or any of its excipients, diagnosed severe hypersensitivity to other IV iron compounds, presence of anemia with causes other than ID , iron overload, or iron metabolism disorders.Oral iron supplementation therapy offers some practical advantages, which are limited where absorption in the gastrointestinal tract is reduced. The IRONOUT-HF study concluded that there was a minimal increase in iron stores in CHF patients with reduced LVEF who followed oral iron therapy. Additionally, no improvement in exercise capacity was recorded . MoreoveRed blood cell transfusion is recommended under careful monitoring in cases of severe anemia  . The theAccording to several authors, the ideal treatment should include the combination of erythropoiesis-stimulating agents with iron therapy, improving symptoms, decreasing hospitalizations, and increasing exercise capacity and quality of life .The use of erythropoietin in treating moderate anemia associated with heart failure can beneficially affect cardiac function, improving both NYHA functional class and LVEF, decreasing atrial natriuretic peptide values, and improving kidney function. However, recombinant human erythropoietin is associated with unfavorable side effects: increased blood pressure due to increased hematocrit and micro vascularization damage, risk of deep vein thrombosis due to increased blood viscosity, and risk of aplastic anemia secondary to the production of anti-rHuEpo antibodies .A human EPO analog, darbepoetin, may also be used, with proven clinical benefits such as exercise capacity and quality of life improvement. However, a randomized, double-blind trial conducted in 2008 (STAMINA-HeFT) claims that darbepoetin alfa treatment, administered subcutaneously every two weeks for 12 months, is well tolerated and increases hemoglobin, while associated morbidity and mortality are lowered .Other studies have stated that current clinical trials of erythropoiesis-stimulating agents have failed to provide convincing evidence of decreased morbidity and mortality or long-term effects, thus highlighting the importance of ID, iron metabolism modification, and hemodilution, with an increased risk of administration due to the high incidence of thromboembolic complications . Hepcidin levels may be normalized by decreasing its production or antagonizing the ferroportin internalization and degradation effect, increasing ferritin levels .ID was observed in approximately 50% of patients with acute decompensated HF, being associated with a longer duration of hospitalization ,66.In patients with coronary artery disease (CAD) or acute coronary syndrome (ACS), anemia and ID are commonly encountered, and their appearance is correlated with the disease’s severity. This association was documented in a study on 2082 patients conducted by Lanser et al., which revealed the relationship between the presence of anemia and the severity of cardiovascular disease . There was an increased level of pro-inflammatory markers, all correlated with an increased risk of cardiovascular events, which could be mainly due to the underlying inflammation. The inflammation incriminated may lead to, and be caused by, atherosclerosis .In patients hospitalized for ACS, the prevalence of ID varied between 29 and 56%, depending on the characteristics of the study groups ,69. A stData on the link between ID and the risk of cerebrovascular disease are sparse and conflicting. The prevalence of ID in stroke patients could be around 45%. A Mendelian randomized trial showed an increased risk of stroke, particularly cardioembolic stroke, in patients with higher serum iron and ferritin or TSAT but lower serum transferrin concentrations . In contThe prognostic significance of ID in cerebrovascular diseases has not been quantified, and, consequently, the prognostic impact of treating ID in these patients is not sufficiently evaluated. However, ID may be associated with a severe clinical status.In a study by Kvaslerud et al., which analyzed 464 patients with aortic valve stenosis, 53% had ID and 20% had anemia. Although patients with ID had a severe clinical profile, no association between ID, TSAT, or hepcidin level and the risk of major adverse cardiovascular events or mortality was demonstrated, regardless of the therapeutic approach of aortic stenosis . Thus, aThe prognostic role of ID in atrial fibrillation (AF) is unknown . ID prevAlthough numerous studies highlight the potential role of ID association with cardiovascular diseases, such as CAD, aortic stenosis, cerebrovascular disease, and AF, the evidence is contradictory, and the underlying pathophysiological mechanisms still need to be completed. Future studies are required to complete the characterization of patients with cardiovascular disease and identify patients who will benefit from iron supplementation therapy .Anemia is frequently encountered in CHF, being a negative prognostic factor. The causes of anemia, incompletely elucidated, are varied and challenging.Screening for ID in patients with cardiac disease is highly recommended, considering its relevance for the prognostics of these patients.Current guidelines recommend only one intravenous iron preparation in CHF—ferric carboxymaltose. The literature has established its beneficial effect, with improvements in quality of life and exercise capacity.The administration of oral iron supplements in patients with CHF is not recommended because of the lack of studies demonstrating its efficacy, the high incidence of adverse digestive effects, and the long treatment periods needed to increase hemoglobin levels.The management of these cases should be handled by a multidisciplinary team, which will collaborate in performing an active screening for diagnosis, prevention, and management to reduce morbidity and mortality from cardiac causes.


Cardiovascular regulatory mechanisms that fail to compensate for ultrafiltration and cause hypovolemia during hemodialysis (HD) are not completely understood. This includes the interaction between the autonomic nervous system and the biochemistry that regulates blood pressure and modulates cardiac activity and vascular tone in response to hypovolemia in patients treated with HD. The objective was to evaluate the association of spectral indices of heart rate variability (HRV) with serum levels of angiotensin II, angiotensin 1–7, nitric oxide and total antioxidant capacity during HD. Electrocardiographic records were obtained from 20 patients during HD (3 h), from which HRV data and spectral power data in the very-low-frequency (VLF), low-frequency (LF) and high-frequency (HF) bands were generated. Three blood samples per patient were collected during HD  to determine the levels of biomarkers involved in the pressor response during HD. Angiotensin II had a positive correlation with VLF (r = 0.390) and with LF/HF (r = 0.359) and a negative correlation with LF (r = −0.262) and HF (r = −0.383). There were no significant correlations between HRV and the other biomarkers. These results suggest that during HD, VLF could reflect the serum levels of angiotensin II, which may be associated with the autonomic response to HD. Hemodialysis (HD) benefits more than 2 million end-stage renal disease (ESRD) patients worldwide  by removHD causes hemodynamic, thermal and respiratory stress, which produce adverse effects in the patient, both in the medium and long term . HemodynFor its part, the renin angiotensin aldosterone system (RAAS) is one of the most important mechanisms that regulates systemic blood pressure and renal hemodynamics; its dysregulation promotes both sodium and water retention and the incidence of arterial hypertension ,5. The RThe effects of the RAAS on the activity of the ANS are reflected in the modulation of the sympathetic and parasympathetic flows that regulate the cardiovascular system . The modThe most common method to obtain HRV is through an electrocardiographic (ECG) recording, from which the time intervals between consecutive R waves are measured to form a time series called the HRV recording or R-R tachogram . HRV assRecent studies on the cardiovascular control in ESRD patients showed that VLF power increases during hemodialysis  and thatConsidering that the standards for HRV spectral analysis do not allow for estimating the VLF with confidence , the corThis prospective, cross-sectional and quasi-experimental study included a nonrandom sample of 20 ESRD patients treated with HD therapy at the Instituto Nacional de Cardiología Ignacio Chávez. All patients signed written consent to participate in the study protocol, which was approved by the Research and Bioethics Committees of our institution (number: 17-1014). Patients received three sessions of HD per week for at least 6 months prior to the start of the study. The study included patients from both sexes, aged between 21 and 68 years old, who were on dry weight without antihypertensive drug treatment and without decompensated lungs or heart disease. Patients with anatomical or functional limitations that prevented the placement of electrodes for ECG recording or who had vascular access dysfunction were excluded. According to the routinely clinical management, patients did not have dietary restrictions beyond the standardized advice for ESRD patients to avoid excess salt and drinking. Patients usually performed aerobic exercise during HD with an ergonomic bicycle without resistance. None of them had a prescription for erythropoietin. They had a stable hemoglobin within an expected target for ESRD without exogenous erythropoietin most likely by two mechanisms: (i) by a preserved nutritional status with unrestricted protein intake; (ii) by the hypoxia-inducible factor pathway activation due to the high altitude of Mexico City, which is 2240 m above sea level, as the beneficial effect of altitudes above 1000 m has been documented on the hemoglobin levels in ESRD patients . The general characteristics of the patients, expressed as the mean ± standard deviation, were age = 37 ± 12 years, albumin = 4.1 ± 0.23 g/dL and hemoglobin = 10.5 ± 2.0 g/dL. Three patients had a history of cardiovascular event. The ESRD etiology was immunoglobulin A nephropathy (n = 2), lupus nephritis (n = 3), hypertensive nephrosclerosis (n = 2), membranoproliferative glomerulonephritis (n = 3), autosomal dominant polycystic kidney disease (n = 1), diabetic nephropathy (n = 1) or undetermined etiology (n = 8). Prior to HD, patients had a weight gain of 2 ± 0.6 kg. During the HD sessions in the present study, patients underwent replacement of 19.5 ± 1.4 L, the uric acid reduction was 81.3 ± 4.3%, urea reduction was 76 ± 5.1%, creatinine reduction was 71 ± 6.8%, phosphorus reduction was 48.5 ± 4.4% and Kt/V at the end of 3 h was 1.47 ± 0.5. Eight patients had intradialytic hypotension. Intradialytic hypotension is defined as a symptomatic decrease in either systolic blood pressure ≥ 20 mm Hg or a decrease in mean arterial pressure of 10 mm Hg. The symptoms associated with the blood pressure drop might include abdominal discomfort, yawning, nausea, vomiting, muscle cramps, restlessness, dizziness, fainting or anxiety.Although patients did not have dietary restrictions in their routinely clinical management, at the end of the last HD session prior to the HD of the study, dietary recommendations were given to the patients so that their interdialytic weight gain did not exceed 2 kg. For those patients who did not adhere to the recommendations, corrective actions were applied during the sessions to standardize the volume extraction. If the weight gain was greater than the pre-established goal, the HD session was extended to reach the patient’s dry weight; if the weight gain was less than the pre-established goal, then a bolus was injected during the session to reach the 2400 mL of liquid extraction established for the protocol. Patients were also asked to refrain from consuming coffee and tobacco for seven days before the study to obtain viable blood samples for assessment of angiotensin II, angiotensin 1–7, nitric oxide and total antioxidant capacity. To maximize the ANS response, during HD therapy all patients were in a supine position without performing physical activity, cognitive tasks or breathing control. Brachial blood pressure, heart rate, central temperature and peripheral temperature were measured with a mCare 300 vital signs monitor . Measurements were taken every 10 min since the beginning of the therapy (0 min) up to the end (180 min). Blood pressure measurements were performed with the oscillometric method. For this study, the measurements considered in the analysis were the ones obtained at the beginning of the HD session, after 1.5 h and after 3 h.2 was used. The blood flow rate ranged between 330 and 430 mL/min, and the flow rate was set to 500 mL/min, with a dialyzing solution at 35 °C. The dialysis solution had the following concentrations: Na+ = 138 mmol/L, HCO−3 = 32 mmol/L, Ca+2 = 2.5 mmol/L, K+ = 2 mmol/L, Mg+2 = 1 mmol/L, acetate = 3 mmol/L and glucose = 200 mg/dL. The ultrafiltration rate was fixed at 800 mL/h to achieve a total extraction volume of 2400 mL over 3 h. A total of 2500 units of heparin was administered to each patient through the venous line of the HD circuit using the following dose: 1000 units were injected as an initial bolus and the remaining 1500 units in continuous infusion during the 3 h of HD. We analyzed a single dialysis session in each patient, without preference for the weekday (8 patients had the mid-week session and 12 had the session during the first day after the weekend).In our routine clinical practice, the hemodialysis prescription  was adjusted to each patient’s needs before each session. Only for the session of this study was the hemodialysis adjusted as follows. All HD sessions were performed in the morning using the same HD machine . A polysulfone filter with an effective surface area of 1.8 mArterial blood samples of 4 mL were taken during HD therapies to assess cardiovascular serum markers. The samples were extracted from the vascular access of the patients from the arterial line circuit before the dialysis filter at the beginning of the HD session, after 1.5 h and after 3 h. The tubes to collect the samples did not have anticoagulant or precipitating gel. During the collection, the blood was poured slowly through the inner wall of the tubes, and during their transportation to the laboratory, they were not shaken to avoid a high degree of hemolysis of the samples.g for 15 min at 4 °C . It was filtered with 0.22 mm nitrocellulose membrane filters , diluted 1:10 with 0.1 M sodium hydroxide  and analyzed directly. For this purpose, the P/ACETM MDQ system  was used, to which the capillary was preconditioned  passing a 0.1 M solution of sodium hydroxide  for 10 min, followed by deionized water  for 10 min, methanol  for 10 min and, finally, the running buffer  for 10 min. The samples were injected under hydrodynamic pressure at 0.5 psi/10 s. Separation was performed at 30 kV for 10 min at 200 nm and 10 °C. The migration time for the angiotensin II was 3.329 ± 0.093 min, and for angiotensin 1–7 it was 5.342 ± 0.112 min. The capillary was washed between runs with 0.1 M NaOH  for 2 min, methanol  for 2 min, deionized water  for 2 min and running buffer for 4 min. The results are expressed in pmol/mL.Angiotensin II and angiotensin 1–7 were determined simultaneously in all samples by capillary zone electrophoresis, according to the methodology of Tenorio LFA et al. (2010) . The sam+3) instead of cadmium (Cd+2). The quantification of nitric oxide was carried out indirectly on the nitrites derived from its degradation, generating a bright green complex, when the diazonium product -ethylenediamine) was coupled with the V+3. This colorful compound turned out to be more stable and less toxic than that generated when Cd+2 is used. Thus, 100 µL of vanadium (III) chloride solution  at 0.8% (p/v) in phosphoric acid  at 1 M was used. It was manually homogenized and 50 mL of the 2% (p/v) sulfanilamide solution  in phosphoric acid  at 5% (v/v). It was manually homogenized and 50 µL of N-(1-naphthyl) ethylenediamine dihydrochloride solution  at 0.2% (p/v) in deionized water . It was manually homogenized and allowed to incubate at room temperature for 45 min, protected from light. After, 3 mL of deionized water  was added, and it was read spectrophotometrically at wavelengths of 572 and 587 nm , adjusting with a reagent blank. To calculate the nitric oxide concentration, the absorbance at 572 nm was subtracted from the absorbance at 587 nm. The results are expressed in pmol/mL.The nitric oxide was quantified indirectly by the method of Tenorio LFA et al. (2005) , which i+2 to Cu+1, due to the effect of circulating endogenous antioxidants. Reduced copper was detected by the formation of stable Cu+1 chromogens in the presence of bathocuproine, which are bright light green in color. Thus, 35 µL of plasma was added to 145 µL of 0.1 M phosphate buffer  at pH 7.5 and homogenized at 500 rpm  for 200 s. Immediately afterwards, 50 µL of 0.01 M copper II chloride  was added and homogenized at 500 rpm  for 200 s. Next, 50 µL of 0.01 M bathocuproine  was added and homogenized again at 500 rpm  for 200 s. Finally, the reaction was diluted to 1000 µL with deionized water  and read spectrophotometrically at a wavelength of 490 nm , previously adjusting with a phosphate buffer blank. Total antioxidant capacity is expressed in mmol/L.Total antioxidant capacity was indirectly quantified by the method of Campos C. et al. (2005) , which iA 7-lead Holter device  with a sampling rate of 128 samples per second was used to acquire the ECG in three leads during HD and to obtain consecutive RR intervals . The eleThe acquired ECG recordings were first resampled with MATLAB  at 256 samples per second using linear interpolation to improve the QRS complex detection ,28. ThenThe HRV records were processed using the continuous wavelet transform, the bands were separated in the time-scale plane, and then the inverse continuous wavelet transform was applied to extract the spectral components of VLF, LF, and HF ,16. Specp-values using the Bonferroni method. To evaluate the association between the RAAS serum markers and the other study variables, Pearson’s correlation analysis was performed. Linear (stepwise) multiple regression models were used to corroborate the association between HRV indices (as dependent variables) and angiotensin II, age, diastolic blood pressure, heart rate, and central temperature (as independent variables). The statistical analysis was performed with the computer program Statistical Package for Social Sciences (SPSS) version 21.0 . A p-value < 0.05 was considered statistically significant. The Kolmogorov–Smirnov test was applied to assess whether the variables had a normal distribution, and logarithmic transformation was applied when necessary to achieve a normal distribution. The results are reported as the mean ± standard deviation. Serum angiotensin II, angiotensin 1–7, nitric oxide and total antioxidant capacity were compared during the three sampled times by analysis of variance (ANOVA) with post hoc adjustment of 2) increased at the end of HD compared to the first measurement at the start of HD (p < 0.05). HF increased in the second measurement when compared to the HF of the first measurement (p < 0.05). The other variables had no significant differences during HD.Considering that there were no significant differences among the three samples for most of the variables , we perfTo further explore the association between HRV indices and angiotensin II, a multiple regression analysis was performed. This study explored the correlation between HRV indices and biochemical parameters during three moments of HD  in a cohort of ESRD patients. Hemodynamic, electrocardiographic and biochemical data were obtained to assess their correlation with markers of the RAAS system  which are involved in the vasodilator response under a stimulating effect of the ANS induced by the hemodynamics’ shear stress.HD is a renal replacement therapy that provokes hemodynamic, thermic and respiratory stress with adverse consequence for the patient . The resThe ESRD patients treated with HD in this study had significant correlations between angiotensin II levels and HRV spectral indices. An increase in angiotensin II during HD was expected as a physiological response to the RAAS activation , althougThe correlations between angiotensin II and HRV spectral indices were expected due to the bidirectional interactions between angiotensin II and the ANS . The VLFFor the study, the spectrum of the total HRV spectral power was estimated and divided into three bands for analysis: high-frequency (HF: 0.15–0.4 Hz), low-frequency (LF: 0.04–0.15 Hz) and very-low-frequency (VLF: 0.003–0.15 Hz) components. 0.04 Hz) . The powHRV analysis is normally performed in 5 min segments of the signal, according to the standards . Regardi2) increased at the end of HD compared to the first measurement at the start of HD (p < 0.05). On the other hand, HF showed an increase in the second measurement when compared to HF of the first measurement (p < 0.05). There were no significant differences during HD in the other variables evaluated.Thus, p < 0.01) and heart rate. Meanwhile, angiotensin II had positive correlations with diastolic blood pressure, core temperature, heart rate, VLF and the LF/HF ratio and had negative correlations with age, LF and HF  show that the hemodynamic response to bleeding is altered . HoweverRegarding the use of anti-hypertensives, our routine clinical practice was focused on regulating blood pressure by providing enough hemofiltration and keeping close follow up on the dry weight of each patient. With this approach, we favored the adaptive response of the physiological mechanisms of each patient to hemodialysis. For instance, we showed that despite their augmented chronic sympathetic predominance, patients in hemodialysis have a preserved autonomic capacity to respond to physiological and hemodynamic stimuli . FurtherIn hemodialysis patients, three main reasons for hypertension are volume overload, derangements of the renin–angiotensin system and sympathetic overactivity . AngioteAs limitations of our work, we had a relatively small sample, which limited the number of variables that could be adjusted in the multivariate analysis. Nevertheless, we were able confirm the association between angiotensin-II and HRV indices by adjusting for potential confounders such as age . The incFuture studies are required to assess the potential clinical impact of RAAS and its interaction with the ANS during hemodialysis, including the risk of intradialytic hypotension, intradialytic hypertension and other relevant outcomes.The results demonstrated that there were correlations between HRV indices and serum angiotensin II levels during HD. These results provide us with the first evidence of the co-activation of the RAAS with the ANS in HD patients and are the basis for further investigation of the physiological response to HD as well as the search for prognostic markers to predict intradialytic cardiovascular instability .


Akkermansia, Albimonas, Escherichia–Shigella, etc. showed significant higher abundance in CKD patients, whereas Flavobacterium, Blastomonas, Lautropia, etc. significantly declined in patients. Escherichia–Shigella achieved an acceptable diagnostic biomarker with area under the curve (AUC) value of 0.784 in the receiver operating characteristics (ROC) curve. In addition, CKD patients with pruritus (P-CKD) had a different bacterial community comparing to those without pruritus (non-P-CKD) and HC group. Several bacterial genera showing significant difference between P-CKD and non-P-CKD/HC, such as Oribacterium, significantly declined in P-CKD patients than that in the HC group, and Methylophaga significantly increased in P-CKD patients compared to that in HC subjects. Escherichia–Shigella was positively associated with the levels of pruritus severity, blood urea nitrogen (BUN), uric acid, and urine protein; Oribacterium was negatively associated with pruritus severity, whereas it was positively associated with estimated glomerular filtration rate (eGFR) and 24-h urine volume. The dysbiotic of skin microbiome in CKD patients and its association with pruritus and renal function shed a light on skin probiotics.Dysbiotic gut microbiome in chronic kidney disease (CKD) patients has been extensively explored in recent years. Skin microbiome plays a crucial role in patients with skin diseases or even systemic disorders. Pruritus is caused by the retention of uremic solutes in the skin. Until now, no studies have investigated the role of skin microbiome in CKD and its association with pruritus. Here, we aim to examine the bacterial profile of skin microbiome in CKD and whether it is correlated to pruritus. A total of 105 CKD patients and 38 healthy controls (HC) were recruited. Skin swab was used to collect skin samples at the antecubital fossa of participants. Bacterial 16S rRNA genes V3–V4 region was sequenced on NovaSeq platform. On the day of skin sample collection, renal function was assessed, and numeric rating scale was used to measure pruritus severity. Principal coordinate analysis (PCoA) revealed a significant difference in bacterial composition between the groups of CKD and HC. A depletion of bacterial diversity was observed in CKD patients.  Chronic kidney disease (CKD) is an important contributor to morbidity and mortality from non-communicable diseases. In 2017, 697.5 million cases of all-stage CKD were recorded, for a global prevalence of 9.1% . CKD proEggerthella lenta, Flavonifractor spp., Alistipes spp., Ruminococcus spp., and Fusobacterium spp , and those on dialysis . PrurituSkin microbiome is correlated with health state, and the accumulation of uremic solutes in the skin contributes to pruritus in CKD patients. Here, we hypothesized that CKD patients had a dysbiotic skin microbiome, and it played a role in pruritus severity.2 or evidence of kidney damage such as albuminuria  ≥30 mg/g], urine sediment abnormalities, electrolyte and other abnormalities due to tubular disorders, abnormalities detected by histology, structural abnormalities detected by imaging, or history of kidney transplantation . Informed consent was provided by all subjects prior to sample collection. Adult CKD patients and healthy controls (HC) were recruited. Diagnostic criteria of CKD include a decreased estimated glomerular filtration rate (eGFR) [<60 ml/min/1.73mantation . CKD patCKD staging criteria is as follows: Stage 1, kidney damage with normal eGFR (<90 ml/min); Stage 2, mild reduction in eGFR (60–89 ml/min); Stage 3a, moderate reduction in eGFR (45–59 ml/min); Stage 3b, moderate reduction in eGFR (30–44 ml/min); Stage 4, severe reduction in eGFR (15–29 ml/min); and Stage 5, renal failure (eGFR <15 ml/min) .Current illness, such as diabetes, hypertension, and cancer, was assessed by reviewing clinical records and medical interviews. The renal function was examined on the day of sample collection. Numeric rating scale (NRS) was used to measure itching severity in participants . The pat2 area from the antecubital fossa was firmly swabbed for at least 30 s , and the isolation procedures were performed according to the manufacturer’s instructions. The total DNA was eluted in 50 μl of elution buffer and stored at −80°C until used for PCR.Participants were asked to avoid bathing/showering and application of any topical agents on their left hand 24 h prior to the sample collection. A 4-cmast 30 s . The swaPCR products were confirmed by 2% agarose gel electrophoresis. Throughout the DNA extraction process, ultrapure water, instead of a sample solution, was used as a negative control to exclude the possibility of false-positive PCR results. Polymerase chain reaction (PCR) amplification of the bacterial 16S rRNA genes V3–V4 region was performed using the universal primers 338F and 806R with 30 cycles. The PCR products were purified with AMPure XT beads  and quantified by Qubit . Amplicon pools were prepared for sequencing, and the size and quantity of the amplicon library were assessed using Agilent 2100 Bioanalyzer  and Library Quantification Kit for Illumina , respectively. The libraries were sequenced using the NovaSeq PE250 platform. To avoid any impact of batch effects, we processed and sequenced all of the saliva samples at once.p < 0.05. The sequencing data obtained in this study have been deposited in GenBank Sequence Read Archive under accession number SRP370056 (https://www.ncbi.nlm.nih.gov/bioproject/PRJNA825583).Paired-end reads were assigned to samples based on their unique barcodes and truncated by cutting off the barcode and primer sequence. Paired-end reads were merged using FLASH. Quality filtering of the raw reads was performed under specific filtering conditions to obtain high-quality clean tags according to fqtrim (v. 0.94). Chimeric sequences were filtered using Vsearch software (v. 2.3.4). After dereplication using DADA 2, we obtained a feature table and feature sequence. Alpha diversity and beta diversity were calculated by normalization to the same sequences randomly using QIIME2. Next, according to the SILVA (v. 132) classifier , featuret-tests and categorical variables using chi-square or Fisher’s exact tests, when appropriate.Descriptive statistics for demographics and clinical characteristics of the CKD and HC groups are presented. To compare demographics and clinical characteristics between the CKD and HC groups, continuous variables were assessed using independent p-value was calculated for comparative tests. A p < 0.05 was used as a cutoff for comparative statistical tests. Next, the bacterial genera displaying significant difference between CKD and HC were selected to perform the correlation analysis between bacterial genus and pruritus severity and renal function.R software (version 3.6.3) was used to perform bioinformatic analysis. The Wilcoxon rank sum test was applied to compare bacterial diversity and the relative abundance of bacterial taxa and metabolic pathways between the CKD and HC groups, and a Benjamini Hochberg false discovery rate (FDR)-corrected p < 0.05; ; 10,988,455 reads were obtained after removing low-quality or ambiguous reads. Good coverage ranged from 98.81% to 100.00%.p = 0.001; p < 0.05; Principal coordinate analysis (PCoA) revealed a significant difference in bacterial composition between the CKD and HC groups , Curvibacter (7.82%), Acinetobacter (5.13%), Enhydrobacter (5.06%), and Staphylococcus (4.82%) were dominated in CKD patients  value of 0.784 . In addition, the bacterial richness and diversity did not show significant difference between HC and patients in each CKD stage and among CKD stages , uric acid, urine protein, and pruritus severity; Eubacterium nodatum group was positively associated with serum creatinine; Trichococcus was positively associated with urine protein; Oribacterium was negatively associated with pruritus severity, whereas it was positively associated with eGFR and 24-h urine volume  of bacteria of the human skin microbiome are classified into four types: Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes . Indeed,Ralstonia, which accounted for 8.34% of the total abundance in CKD patients, and it was listed as the top 1 abundant bacterial genus in patients. The association between Ralstonia and health state has never been reported by human microbiome study. Further study is needed to explore its function in the skin.We noticed that Proteobacteria demonstrated slightly higher abundance in CKD patients than that in HC group. High level of Proteobacteria in the gut is responsible for unhealthy states, including CKD . The enrEscherichia–Shigella was not only increased in CKD patients but also can be listed as a moderate diagnostic biomarker in patients. Escherichia–Shigella was also considered a diagnostic tool in the gut of CKD patients in the study of Escherichia–Shigella compared to HC group. Its abundance was not significantly correlated to patient’s eGFR. This finding was inconsistent to the study of Escherichia–Shigella in the gut was positively correlated to patient’s renal function  can be found below: The studies involving human participants were reviewed and approved by the ethics committee of the Affiliated Wuxi Second Hospital of Nanjing Medical University (Ref. 2018051). The patients/participants provided their written informed consent to participate in this study. Written informed consent was obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article.Conceptualization: PJ, WG, and NF. Methodology: YT, YF, JS, LH, CG, PJ, and FY. Software: YG and JC. Validation: NF. Writing: YT and YG. Supervision: NF. Funding acquisition: NF. Project administration: LH, PJ, JC, JS, CG, YF, and FY. All authors contributed to the article and approved the submitted version.This study was supported by Wuxi “Taihu Talents Program” Medical and Health High-Level Talents Project (THRCJH20200901), Wuxi “Key Medical Discipline Construction” Municipal Clinical Medical Center  Project (LCYXZX202103), Zhejiang Provincial Natural Science Foundation of China (LXR22H160001), and National Natural Science Foundation of China (81874142 and 82073041).The handling editor JY declared a shared parent affiliation with the author YG at the time of review.The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.