The study included 80 children and adolescents (median age 9.75 year) with congenital and acquired  SFK. Serum TWEAK and urinary MCP-1 and RANTES levels were significantly higher in SFK patients (p < 0.05). The serum TWEAK was positively related to serum creatinine . Moreover, in SFK the receiver operating characteristic analyses revealed good diagnostic profile for serum TWEAK with AUC (Area Under The Curve)—0.853, uRANTES—0.757, and for RANTES/cr.: AUC—0.816. Analysis carried out to identify children with impaired renal function  showed good profile for TWEAK (AUC—0.79) and quite good profile for uRANTES and RANTES/cr. . This is the first study investigating serum TWEAK and urinary excretion of MCP-1 and RANTES together in children with SFK. Obtained results indicate that TWEAK and RANTES may serve as potential markers of renal impairment.This study was performed to explore serum tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its dependent cytokines urinary excretion: monocyte chemoattractant protein- Congenital anomalies of kidney and urinary tract (CAKUT) are one of the most common defects seen in newborns, with occurrence from 1:500 to 1:2000 births [People with congenital absence of one kidney  or loss due to disease or kidney donation have decreased renal mass which is associated with compensatory increase in glomerular filtration rate (GFR) of the other kidney. The clinical significance of the reduced number of nephrons was described over thirty years ago by Brenner et al.  in the tThe importance of the problem is evidenced by the fact that main causes of chronic kidney disease (CKD) in the pediatric population are congenital anomalies of the kidneys and urinary system, which account for approximately 50% of all cases. Due to the improvement of perinatal care and more effective treatment of children with CAKUT, more and more patients survive to adulthood and develop symptoms of CKD.The tests assessing kidney function  available in routine diagnostics are still not perfect, and most importantly, they do not detect subclinical changes. Proper biochemical assessment of patients with kidney disease is extremely important from the clinician’s point of view. Progressive kidney damage is often asymptomatic or mildly symptomatic for a very long time. Therefore, only the early detection of this damage on the basis of laboratory tests can help to reduce the risk of chronic complications and slow down the progression of the disease. That is why the search for new biomarkers with high sensitivity and specificity for the assessment of early renal impairment is ongoing.Recent years, there has been a growing interest in the role of a protein important in the diagnosis of inflammatory and systemic diseases with multi-organ involvement, such as the tumor necrosis factor-like weak inducer of apoptosis (TWEAK). TWEAK belongs to the tumor necrosis factor superfamily of cytokines . It is aIn studies carried out on a mouse model, TWEAK, apart from causing a direct inflammatory reaction, also stimulated mesangial cells, endothelial cells and podocytes to secrete cytokines, including the monocyte chemoattractant protein-1  and regulated on activation, normal T cell expressed and secreted chemokine . TWEAK was also confirmed to be a promoter of non-inflammatory compensatory hypertrophy of the kidney after unilateral nephrectomy in mice .Hence, the question whether, similarly to the mouse model, also in children with a solitary functioning kidney, the concentrations of the above-mentioned markers increase and whether there is a relationship between their levels and the progression of chronic kidney disease.The aim of this study was to 1. Assess and compare serum TWEAK concentration and urinary excretion of MCP-1 and RANTES in patients with congenital and acquired solitary functioning kidney; 2. Test TWEAK and the cytokines MCP-1 and RANTES potential usefulness as biomarkers of renal impairment in children with solitary functioning kidney; 3. Determine probable cut-off points, which may be used in clinical practice in differentiation of SFK children with impaired renal function.The study included 120 children and adolescents with congenital and acquired SFK and healthy peers diagnosed and treated at the Department of Pediatrics and Nephrology, Medical University of Bialystok and the Department of Pediatrics, Gastroenterology, and Nutrition, University of Warmia and Mazury, Poland.2 and/or hypertension)—this subgroup consisted of 52 children  and those whose kidney function was normal —28 children .The study group (B group) was divided into 2 subgroups. The A group consisted of 54 children  with congenital unilateral renal agenesis; N group—26 children  with acquired  SFK. Additionally, patients from the study group (group B) were divided into those with features of impaired renal function . The group N included children whose nephrectomy was a consequence of a congenital kidney defect or trauma.Exclusion criteria were: presence of other organs chronic diseases, a recent (within 4 weeks) acute illness of any kind, as well as clinical or laboratory signs of infection , use of drugs that may affect kidney function, other abnormalities in kidney ultrasound.The exclusion criterion in the N group was nephrectomy due to a kidney tumor, in order to exclude the influence of chemotherapy on the obtained results.The reference group (K) consisted of 40 children , appropriately matched according to sex and age. Subjects in the reference group were recruited among medical staff children, and among participants from the OLAF study .Inclusion criteria for the reference group: children and adolescents aged 1 month to 18 years, born at term, with normal birth weight, in whom physical examination, blood and urine laboratory tests, and kidney ultrasound were normal. Children were in good overall health, without history of a recent (within 4 weeks) acute illness of any kind, and any history of chronic diseases. They were not taking any medications relevant to kidney disease. No data relating the risk of hypertension and other cardiovascular diseases, diabetes or gout were found.Demographic and clinical data were assessed. In all children, careful clinical history, underlying comorbidities and physical examination were estimated. Blood pressure (BP) was measured using either a manual auscultatory or an automatic oscillometric device. High BP was defined as systolic BP (SBP) and/or diastolic BP (DBP) values above the 95th percentile adjusted for age, gender, and height. SBP and DBP load was calculated as the percentage of readings exceeding the 95th percentile for age, sex, and height percentile during each period. BP load analyses were conducted using 25% as the cut-off value .Venous blood for biochemical tests  was collected in the morning after an overnight fast. Laboratory tests in all patients were performed during routine diagnostics.The estimated glomerular filtration rate according to Schwartz (eGFR) was calculated with use of the formula: eGFR = 0.413 × height in cm/serum creatinine in mg/dL .Excretion of urinary albumin  was determined in the urine collected during a 24 h period. In younger children, due to the difficulty in collecting 24 h urine, the albumin/creatinine ratio in the morning urine sample (UACR) was assessed. Albuminuria was defined as a daily excretion in the range of 30–300 mg/24 h and UACR 30–300 mg/g creatinine.TWEAK concentration was determined by commercially available sandwich ELISA immunoassay kit from MyBioSource Inc., San Diego, CA, USA.Urinary levels of MCP-1 and RANTES (uMCP-1 and uRANTES) were determined using a commercially available immunoassay kits from Wuhan Fine Biotech Co., Ltd., Wuhan, Hubei, China.The urine for the determination of the tested markers levels  was collected from the first morning urine sample into a disposable container. The urine was centrifuged and specimens were stored at <−80 °C for up to 6 months. Urine samples were gradually thawed at room temperature prior to testing.The study was approved by the Bioethics Committee of the Medical University of Bialystok (RI-002/137/2018) and the Bioethics Committee at the Faculty of Medical Sciences of the University of Warmia and Mazury in Olsztyn (No. 27/2017).p < 0.05 was used in all tests.The statistical analysis was performed using the Statistica 12.0 PL computer program . The significance level of The relation between estimated markers and baseline characteristics was assessed using the Spearman or Pearson correlation analyses.A receiver operating characteristic (ROC) curve analysis was performed to determine the predictive value of estimated biomarkers as well as to define their optimal cut-off values.Additionally, to search for the optimal cut-off point to differentiate patients with impaired renal function from those with normal renal function the method of Classification and Regression Trees (CART) was used.The demographic, anthropometric, biochemical parameters and estimated biomarkers in patients and control subjects are shown in p < 0.05). Congenital unilateral renal agenesis was diagnosed at the median age 3.67 years ; the median age at which the nephrectomy was performed was 0.91 years . Comparison of patients between groups with congenital and acquired SFK showed significantly higher values of systolic blood pressure in manual measurements in the group of children with unilateral renal agenesis (p < 0.05). No differences were found between A and N groups (p > 0.05).The demographic and anthropometric parameters  did not significantly differ among the groups (B vs. K). Higher values of systolic blood pressure were found in the group of children with SFK (group B) compared to the reference group (p > 0.05).Both, in the group with unilateral renal agenesis (A), as well as in patients after nephrectomy (N), there were no significant differences between female and male patients in the assessed demographic and anthropometric parameters , laboratory parameters , and blood pressure  and healthy subjects (K), but not between the nephrectomy (N) and the reference (K) groups.p > 0.05).Moreover in the group of patients with unilateral renal agenesis (A) and after nephrectomy (N), albuminuria was found, without significant differences between these groups (p < 0.0001). Urinary excretion of MCP-1 and RANTES in B group, both presented in pg/mL and in values adjusted to creatinine (pg/mg cr.), showed significant increase in comparison to healthy peers (p < 0.05).The serum concentrations of TWEAK in the study group (B) were much higher than in the reference group . The median serum TWEAK in the reference group was 164.94 pg/mL, and revealed significant difference between groups A vs. K, and N vs. K (p < 0.0001). Higher excretion of uMCP-1 (pg/mL) was demonstrated only in patients with unilateral renal agenesis (A) compared to the reference group (K) (p < 0.05). MCP-1 urinary excretion adjusted to creatinine (MCP-1/cr.) showed similar pattern between A vs. K groups (p < 0.05).The median serum concentration of TWEAK in patients from group A was 486.09 pg/mL, and in group N it was 577.18 pg/mL. These values did not differ significantly between SFK groups (p < 0.01). Higher values of uRANTES were also found in the group of patients after nephrectomy (N) compared to the reference group (K) (p < 0.01). Similarly, the ratio of urinary RANTES to creatinine concentration (RANTES/cr.) was much higher in children with congenital (A) and acquired solitary functioning kidney (N) compared to the reference group (K) (p < 0.01).Increase in urinary RANTES (pg/mL) was found in patients with congenital SFK patients (A) compared to the reference group (K) .Further tests were carried out to identify correlations of estimated markers with parameters of renal function. As shown in 2 and/or hypertension. The presence of albuminuria was found in 47.5% of patients from the study group, . In total, 55% of all patients in the study group had eGFR <90 mL/min/1.73 m2, including 50% in the A group, and 65.4% in the group with acquired SFK. Hypertension was found in 15% of children from the study group . Interestingly, higher TWEAK serum concentrations were observed in studied children with albuminuria and normal eGFR in comparison to control individuals with comparable eGFR and non-albuminuria .In additional evaluation we found that 52 patients (65%) from the study group (B) showed renal impairment defined with albuminuria and/or decreased eGFR <90 mL/min/1.73 m2 and/or hypertension) among studied patients  in identifying children with SFK among all examined children A, which patients B, showedFurthermore the CART classification tree method was used for the differentiation of patients with impaired renal function from those with normal renal function.CART showed that the most optimal cut-off point of the serum TWEAK was value of 395.628 pg/mL. Patients with measurements above this value can be classified as participants with impaired kidney function, as in the study group (B) 76.6% of patients with TWEAK levels above 395.628 pg/mL presented with features of impaired kidney function . It should be noted that when analyzing with ROC curve, a cut-off point of 421.934 pg/mL was determined  leads to hyperfiltration of a single nephron and nephron hyperplasia. Hence, for a long time, we may not see an increase in creatinine concentration or observe albuminuria in the presence of SFK. Overload of individual nephrons leads to focal glomerulosclerosis and interstitial fibrosis what was confirmed in kidney biopsy of patients with unilateral renal agenesis ,14.Over the years, the search for markers of impaired renal function has been carried out, which would have a much greater sensitivity and specificity than creatinine, and would allow for subclinical kidney damage detection, differentiation between patients with mild to severe impaired renal function, and earlier implementation of therapies slowing the progression of the disease.The discovered representative of the tumor necrosis factor superfamily—TWEAK seems to be a good candidate for the role of such a marker. It is still the subject of many studies, and its role, and importance in the course of various diseases in humans is still not fully understood.It has been shown that TWEAK, by stimulating Fn14 receptors, directly induces an inflammatory response within the glomeruli and interstitium with the expression of various pro-inflammatory molecules, including MCP-1 and RANTES cytokines. It may stimulate angiogenesis and initiate the process of fibrosis ,16. In vIn the present study, we undertook the assessment of TWEAK and selected markers of fibrosis (MCP-1 and RANTES) in children with SFK, and their correlation with the parameters of kidney function. We tried to answer the question whether they might serve as potential indicators of early renal impairment.Initially, the analysis included a comparison of biochemical parameters in studied children. Study by Schreuder et al.  conducte2; in the KIMONO study eGFR < 60 mL/min/1.73 m2).In the largest retrospective KIMONO study ,21, whicThen we analyzed the concentrations of the tested markers. In the available literature, we have not found data on the assessment of TWEAK concentration in children with SFK. Our study revealed higher serum TWEAK in the study group than in the reference group, and these differences were significant. Further, a separate analysis of TWEAK concentrations in group A and group N showed significant increase in TWEAK in group A compared to group K and in group N vs. K. However, there were no significant differences in the serum TWEAK between patient groups A and N. These results may indicate that an assessment of serum TWEAK levels could be useful in distinguishing patients with reduced nephron mass from those who have both normal kidneys. However, based on the evaluation of TWEAK values, it is not possible to differentiate the cause of the reduced presence of a solitary functioning kidney—congenital or acquired. Obtained results also raised the question if this molecule is accumulating due to eGFR decline? All of evidence suggests that TWEAK is involved in the pathological processes that occur locally in the kidneys. Indeed, it is unknown whether a relevant increase in the production of TWEAK or a severe reduction in renal filtration of TWEAK may increase their serum concentrations. Currently it is thought that TWEAK levels increase in patients with impaired renal function. However, up to now, very few data are available on the precise relationship between TWEAK and the level of GFR. In fact, in patients with severe decline in eGFR serum concentrations of different proteins are definitely increased, and as a consequence, the filtered load of these proteins to the residual nephrons may become higher than single-nephron maximal tubular reabsorptive capacity, increasing its urinary excretion. Interestingly, the urinary excretion of molecules begins from different threshold values of GFR and at different levels of serum concentrations, indicating that proximal tubular cells probably have a different reabsorptive capacity for the different proteins.The largest amount of data from the literature regarding TWEAK levels concerns adult patients with lupus nephropathy. In 2007, Schwartz et al. in a cross-sectional, multicenter study  found thFurther results were obtained in terms of MCP-1 and RANTES urinary excretion (both in pg/mL as well as in pg/mg of creatinine). The couple of tested cytokines showed significantly higher values in the study group than in the reference group. A detailed analysis comparing the urinary excretion of the tested biomarkers in studied subgroups did not show significant differences in the urinary MCP-1 and RANTES between the unilateral renal agenesis group and the nephrectomy group. MCP-1 levels, both in pg/mL and expressed as pg/mg cr., were significantly higher in group A compared to the reference group. There was no difference in MCP-1 excretion between N and K groups. The analysis of RANTES revealed significant differences both between patients with unilateral renal agenesis and the reference group; as well as between nephrectomized patients and the healthy peers. Thus, it seems that the determination of RANTES concentrations in urine could be used to differentiate patients with SFK from those with two normal kidneys.There is a little data in available literature on the assessment of MCP-1 concentration in the urine of children with a single kidney.In study conducted in adults living kidney donors the authors concluded that MCP-1 concentration in urine may detect early tubulointerstitial fibrosis in adults with normal renal function determined with normal creatinine levels and absence of albuminuria, and can therefore be considered a non-invasive marker of renal fibrosis . In anotPromising results of studies of this marker in adults with various kidney diseases, but also in children with urinary tract defects, suggest that MCP-1 could be a potential biomarker for the assessment of early kidney damage also in children with a single functioning kidney. Our study confirmed higher values of MCP-1 in SFK group, but there was no possibility to differentiate with its use between agenetic and nephrectomized patient.The RANTES cytokine was also assessed as a potential biomarker of kidney damage in patients with systemic lupus erythematosus. In the group of 88 adult patients, Chan et al.  found a Finally we tried to determine the cut-off points of the studied markers by analyses with the use of ROC curve and CART classification trees, which would allow us classifying children with SFK group with normal and impaired kidney function on the basis of the studied markers levels.The ROC analysis determined the cut-off point for TWEAK equal to 421.934 pg/mL. Patients with a TWEAK levels above this value showed evidence of renal impairment, and the test specificity was 76.7%, and sensitivity 79.1%.2 and/or hypertension). It should be noted that in both analyses the proposed cut-off point was similar.The analysis of CART classification trees showed that the most optimal cut-off point of patient differentiation is the TWEAK value of 395.628 pg/mL. Patients with serum TWEAK concentration above this value can be classified as impaired kidney function, because in the group with TWEAK > 395.628 pg/mL 77.60% of patients showed signs of renal impairment (albuminuria and/or decreased eGFR < 90 mL/min/1.73 mFor uMCP-1 concentrations, on the basis of the performed analyses, it was not possible to obtain the optimal concentration that would clearly indicate the presence of impaired renal function in patients with SFK.In the case of uRANTES, the ROC analysis determined the cut-off point equal to 10.734 pg/mL. Patients with uRANTES above this value showed renal impairment, and the test specificity was 86.5%.Based on the CART classification trees analysis, it was possible to determine the optimal division point—6.826 pg/mL. Among the patients with uRANTES levels above this value, 64.29% had impaired renal function. Further analysis with CART trees allowed the determine even more optimal level of uRANTES. The value of 10.332 pg/mL definitely differentiates patients into those with normal and impaired renal function, as 80.95% of patients with uRANTES concentration above 10.332 pg/mL showed features of impaired renal function. It is also very important that both the cut-off points in the ROC curve and CART trees are almost identical.The results presented in this study confirm that in patients with unilateral renal agenesis and acquired SFK, increased serum levels of TWEAK as well as increased urinary RANTES excretion are observed in comparison to the reference group. Increased excretion of uMCP-1 occurs only in patients with congenital SFK. Unfortunately, no significant correlations between serum TWEAK concentration and urinary excretion of tested chemokines could be established. However, it was possible to confirm a significant positive correlation between serum TWEAK and creatinine concentrations.All assessed markers achieved significantly higher concentrations in patients with SFK and features of impaired renal function, compared to those who did not show impaired function. Therefore, it is possible to use their determination to differentiate patients with a solitary functioning kidney with features of impaired renal function from those with normal kidney function. It should be mentioned that our study failed in differentiation between unilateral renal agenesis and acquired SFK with use of estimated markers.We are fully aware of the limitations of the study, being small, single center and cross-sectional. Moreover, most of our patients were young children, an appropriate measurement of blood pressure in children is difficult because of “white coat” anxiety, widely varying arm size, and occasional poor cooperation. Furthermore, in prepubertal and younger children no formula of GFR estimation gives acceptable results. It is still controversial, whether in this population a correct estimation of GFR could be obtained from serum creatinine concentration. We still do not know which formula is the least misleading in younger children.Further work is necessary to better define obtained results. For example, better standardization of methods for its measurement in serum and urine, evaluation of MCP-1, RANTES activity in serum, assessment of its protective role in renal injuries once damage has already occurred. Additional efforts comparing serum TWEAK concentration with its urinary excretion would be helpful for detailed answer the question of molecules accumulation due to eGFR decline.In conclusion, what is extremely important, in the case of serum TWEAK and urinary RANTES it was possible to determine the optimal cut-off values, exceeding of which may indicate impaired renal function in patients with a solitary functioning kidney. It might be useful in clinical practice in establishing the reference values of new biomarkers in patients with solitary functioning kidney.Reached results indicate that the tumor necrosis factor inducer, TWEAK, and the cytokine RANTES may serve as potential biomarkers of early renal impairment and suggest possible relationship between TWEAK and uRANTES levels and the degree of renal impairment. However, more studies on a larger group of patients are needed to confirm these preliminary data.


Introduction: Simple renal cysts (SRCs) are the most common acquired cystic kidney disease, but the relationship between SRCs and renal function has not been clarified in patients with type 2 diabetes mellitus (T2DM).Methods: A retrospective study was conducted to analyze the clinical features of renal cysts and ultrasound data of the kidney in 4,304 patients with T2DM.Results: The prevalence of SRCs in patients with T2DM was 21.1%. Compared to patients with no SRCs, patients with SRCs had worse renal function . After adjusting the confounders, SRC was related to estimated glomerular filtration rate in patients with T2DM . Age, gout, proteinuria, cerebrovascular disease (CVD), and increased serum phosphorus levels were associated with SRCs in patients with T2DM.Conclusion: SRCs are associated with worse renal function in patients with T2DM. More attention should be paid to gout, proteinuria, CVD, serum phosphorus levels, and renal function in T2DM patients with SRCs. Simple renal cysts (SRCs) are the most common acquired cystic kidney disease. Microdissection suggests that they might be the diverticula of the distal convoluted tubules or collecting ducts . The incAccording to a recent study, approximately 463 million patients had been diagnosed with diabetes through 2019, of which type 2 diabetes mellitus (T2DM) accounting for around 90%. The number is increasing annually . The assThe study aimed to demonstrate the relationship between renal cysts and renal function and analyze the related factors for SRCs in patients with T2DM.Seven thousand three hundred ninety-eight patients with T2DM who were hospitalized in the Department of Endocrinology in the Second Xiangya Hospital of Central South University in Hunan Province, Changsha City between 2014 and 2018 were enrolled. The inclusion criteria were (i) patients diagnosed with T2DM according to the criteria of the World Health Organization published in 1999  and (ii)2 (m2)], and waist-hip ratio were all obtained from the medical records of each patient. Venous blood samples were collected in the morning after an overnight fast to measure the serum concentrations of total cholesterol (TC), total triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), albumin (ALB), fasting plasma glucose (FPG), glycosylated hemoglobin (Hb1Ac), uric acid (UA), serum creatinine (SCr), phosphorus, and calcium. The plasma creatinine in our hospital was measured by Jaffe’s kinetic method on a Hitachi analyzer. The eGFR (ml/min/1.73 m2) was calculated by using the recommended modified glomerular filtration rate estimating equation for Chinese patients: 175 × [serum creatinine concentration (μmol/L)/88.4]−1.234 × [age (years)]−0.179 ×  /height female) . The ultt-test, the skewed continuous variables were statistically analyzed using the Mann-Whitney U test, and the distributed variables were compared using the Chi-square test in the analysis of the baseline characteristics. Continuous variables with statistically significant differences (p < 0.05) in the Student’s t-test were converted into categorical variables. Regarding the conversion criteria, age was grouped based on the median age of 59 years old, systolic blood pressure (SBP) was grouped based on 140 mmHg, the duration of the disease was grouped into less than 10 years and more than 10 years, and waist-to-hip ratio was grouped based on 0.9 in males and 0.8 in females. BMI was divided into three groups including less than 24 kg/m2, 24~28 kg/m2, and more than 28 kg/m2. Hemoglobin, PLT, TG, TC, FPG, HbA1c, SCr, UA, urine PH, and the concentration of serum phosphorus and calcium were divided by the normal value or upper and lower limit value, a 24 h urinary albumin level <30 mg/d was defined as the no albuminuria group and ≥30 mg/d was divided into microalbuminuria (MIAU) or macroalbuminuria (MAAU) group. Second, multivariable logistic regression analysis was conducted to estimate the associations between the variables and eGFR in patients with T2DM as described previously . The normal distribution of all continuous variables was evaluated using a graphical method. Categorical variables are reported as the number and percentage of patients in each group. The relationship between the normally distributed continuous variables and renal cysts was statistically analyzed using Student’s eviously . Brieflyp less than 0.05 in the aforementioned analysis.In addition, multivariable logistic analysis was also used for estimating the association of variables and SRCs. Variables that were significantly different between patients with and without SRCs were included in the logistic analysis, including age, gender, disease duration, waist-hip ratio, hemoglobin, PLT, TG, TC, FPG, HbA1c, SCr, 24 h urinary albumin, calcium, phosphorus, smoking, drinking, urolithiasis, history of gout, DF, DK, hypertension, CVD, fatty liver, and insulin therapy. A multivariate logistic regression analysis was conducted to identify the risk factors for SRCs. Statistical significance was defined as a value of p was significant , p < 0.01]. After adjusting for the confounders, such as males, age > 59 years old, duration > 10 years, urolithiasis, hemoglobin < 110 g/l, ALB < 40 g/l, TG > 1.71 mmol/l, HbA1c > 6%, UA > 416  or 357, MAAU, DAN, DN, DK, hypertension, CHD, CVD, UTI, phosphorus > 1.51 mmol/L, the association between SRCs and decreased eGFR was still significant . Patients were divided into two groups based on the median value, S < 224 mm2 and S ≥ 224 mm2, to further study the effect of the size of renal cysts on the renal function of patients. The distribution of the SRC based on the size is shown in the p = 0.043). However, the statistical significance might be due to the large population. Moreover, when patients were classified according to unilateral, bilateral, single, multiple, and no renal cysts, no significant differences were observed in the length of the kidney between the two groups , including age, gender, disease duration, waist-hip ratio, hemoglobin, PLT, TG, TC, FPG, HbA1c, SCr, 24 h urinary albumin, calcium, phosphorus, smoking, drinking, urolithiasis, history of gout, DF, DK, hypertension, CVD, fatty liver, and insulin therapy  and 2. Ap < 0.05; p < 0.05; p < 0.05). In addition, among patients over 67 years old, the incidence of SRCs was significantly increased in patients with a high level of uric acid compared to patients with normal level of uric acid, but a noticeable difference was not observed in other age groups . Therefore, the difference of kidney size between the two groups was negligible for diabetic patients in this study. Regarding the large volume of kidneys with multiple cysts, we also found this problem in clinical practice, but there was no obvious difference in this study between the two groups. The reason may be the large sample size of the study, and the average value of eGFR in our study population is more than 90 ml/min/1.73 m2, which reflects that there is no significant relationship with CKD. Therefore, this study did not reflect the size of the kidney changes but it is certainly worth further study on this subject. Furthermore, the number and location of renal cysts were not correlated with the renal length in the comparison between the two groups.In summary, we observed a higher incidence of SRCs in patients with T2DM. The SRC was correlated with proteinuria and reduced eGFR in patients with T2DM. More attention should be paid to gout, proteinuria, CVD, serum phosphorus levels, and renal function in T2DM patients with SRCs.The original contributions presented in the study are included in the article/The studies involving human participants were reviewed and approved by The Medical Ethics Committee of the Second Xiangya Hospital of Central South University. The ethics committee waived the requirement of written informed consent for participation.LS: conception and design. LW, YX, and XX: collection and assembly of data. LW, LL, YH, HZ, and MY: data analysis and interpretation. LW: manuscript writing. YY: read through and corrected the manuscript. All authors contributed to the article and approved the submitted version.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.


Rahnella, Ruminococcus_g2, and Clostridium_g21 were significantly higher in patients with IgAN than in healthy controls (corrected p < 0.05). The relative abundances of several taxa were correlated with the estimated glomerular filtration rate, blood urea nitrogen, haemoglobin, and serum albumin levels. Based on our findings, tonsillar microbiota may be associated with clinical features and possible immunologic pathogenesis of IgAN.Immunoglobulin A nephropathy (IgAN) involves repeated events of gross haematuria with concurrent upper airway infections. The mucosal immune system, especially the tonsil, is considered the initial site of inflammation, although the role of the tonsillar microbiota has not been established in IgAN. In this study, we compared the tonsillar microbiota of patients with IgAN (n = 21) and other glomerular diseases (n = 36) as well as, healthy controls (n = 23) from three medical centres in Korea. The microbiota was analysed from tonsil swabs using the Illumina MiSeq system based on 16S rRNA gene. Tonsillar bacterial diversity was higher in IgAN than in other glomerular diseases, although it did not differ from that of healthy controls. Principal coordinates analysis revealed differences between the tonsillar microbiota of IgAN and both healthy and disease controls. The proportions of  It usually affects young individuals and a significant proportion of cases eventually progress to kidney failure3. The prevalence and genetic risk of IgAN are higher and the kidney prognosis is worse in Asians than in other populations5. IgAN has been recognised as a mild glomerulonephritis initially, but a significant proportion of patients progresses to end-stage kidney disease and their mortality rate is higher than matched controls7. Although the aetiology and pathogenesis remain unclear, mucosal immunity is associated with the development of IgAN. Patients with IgAN frequently suffer from kidney manifestations, such as gross haematuria, flank pain, or kidney swelling, and rarely develop acute kidney injuries simultaneously or immediately after upper respiratory or gastrointestinal illness8. Various factors may explain these clinical features. For example, they could be related to serum galactose-deficient IgA1 level, which is important in the pathogenesis of the disease and is produced in mucosal tissues. The mucosal synthesis of galactose-deficient IgA1 is influenced by the innate immune system via toll-like receptors9. Additionally, the gut microbiota is a critical factor for the production of IgA in the intestinal mucosa of a mouse model10. Significant loci for IgAN are associated with the maintenance of the mucosal barrier and response to mucosal pathogens based on a genome-wide association study11.Immunoglobulin A nephropathy (IgAN) is the most prevalent primary glomerulonephritis worldwide12. Accordingly, the tonsil is considered the initial site of inflammation, and tonsillectomy has well-established beneficial effects in patients with IgAN suffering from recurrent tonsillitis14, either alone or in combination with steroid therapy18. Furthermore, several bacterial antigens are known to induce IgAN22.The tonsil is a central site for antigen processing in the mucosal immune system and the first defensive organ against gastrointestinal entry. A common clinical manifestation of IgAN is macroscopic haematuria, which often coincides with tonsillitis23. However, this previous study was based on single-centre data, and urinalysis data were lacking for paediatric patients in the control group, making it impossible to exclude hidden glomerular diseases. In this study, we characterised the tonsillar microbiota in patients with IgAN in comparison with that in healthy controls—consisting of live kidney donors without evidence of kidney disease—and disease controls with biopsy-proven diabetic nephropathy (DN) and membranous nephropathy (MN) in multiple centres. Our findings extend our understanding of the role of the tonsillar microbiota in the pathogenesis of IgAN.The microbiota signature in the tonsils of patients with IgAN has not been fully elucidated. A recent study of the tonsillar microbiota did not show any difference among IgAN, recurrent tonsillitis, and tonsillar hypertrophyA total of 80 subjects were included, including 21 patients with IgAN, 21 patients with MN, 15 patients with DN, and 23 healthy subjects. Clinical characteristics are summarised in Table A total of 3,443,894 sequence reads  were obtained from 80 tonsil swabs. The diversity indices after normalisation are summarised in Supplementary Table Streptococcus, Pseudomonas, Neisseria, and Haemophilus were the dominant genera (> 5% in each group) in all groups. The relative abundances of Rahnella, Ruminococcus_g2, and Clostridium_g21 were significantly higher in the IgAN group than in the healthy control group  . The relative abundances of two genera, UN) Fig. . In partRahnella, Ruminococcus_g2, and Clostridium_g21 were relatively abundant in the tonsils of patients with IgAN. In addition, the tonsillar microbiota was related to clinical features, especially kidney function. To our knowledge, this is the first comparative analysis of the tonsillar microbiota of patients with IgAN and other glomerular diseases.We detected genus-level differences in the microbiota of the tonsils of patients with IgAN, patients with other kidney diseases (MN and DN), and healthy controls. 24. Bacterial richness was higher in the IgAN and healthy control groups than in the MN and DN groups. In previous studies, Haemophilus parainfluenzae and Staphylococcus aureus have been identified as candidates for the induction of IgAN22. Treponema and Campylobacter rectus are also associated with the development and progression of IgAN25. Prevotella, Porphyromonas, and Treponema are more abundant in patients with IgAN than in patients with tonsillar hyperplasia23. However, in our study, Haemophilus was the dominant genus in all groups; Staphylococcus, Treponema, and Campylobacter were detected in all groups  based on 16S rRNA genes. Ruminococcus_g2 belongs to a cluster including Ruminococcus bromii and uncultured Ruminococcus. R. bromii has been detected in the microbiota of adenoiditis and tonsillitis32 and in the intestine of patients with HIV-1 infection33. Clostridium_g21 belongs to a cluster including Clostridium scindens and uncultured Clostridium. C. scindens can covert glucocorticoids into androgens34 and is involved in resistance to C. difficile infection35. These three bacteria related to tonsillitis are especially abundant in the tonsils of patients with IgAN. They are therefore novel candidates for the pathogenesis of IgAN or for related differences in the immune system status.Three bacteria showed higher abundances in the IgAN group than in the healthy control group. 36. The tonsil has immunological functions, and the tonsillar microbiota may be more closely related to pathogenesis of MN than to the pathogenesis of DN. Differentially abundant genera in the tonsillar microbiota of each kidney disease are candidates for further functional studies.We did not detect genera with significant differences in abundance between the MN and DN groups. We observed more genera differing between the healthy control and MN (17 genera) or DN groups (10) than between the healthy control and IgAN groups (6). The observed differences in the tonsillar microbiota among kidney diseases could be associated with the pathogenesis or progression of each disease. In particular, we detected greater differences between MN and healthy control or IgAN groups than between DN and the healthy control or IgAN groups. The development of DN involves chronic systemic inflammation, whereas primary MN is an autoimmune disease mainly mediated by antibodies to podocyte antigens, the M-type phospholipase A2 receptor and thrombospondin type 1 domain-containing 7A38. Hypoalbuminaemia is common in advanced chronic kidney disease including including end-stage kidney disease39 and is associated with high mortality in acute kidney injury and chronic kidney disease40. In our study, Acinetobacter and uncultured Moraxellaceae were related to better kidney function and higher levels of plasma haemoglobin and serum albumin in all kidney diseases. The similar patterns for the relationships between these parameters and specific bacteria provide a basis for further clinical studies, particularly given the lack of research on the role of tonsillar microbiota in kidney diseases.We detected correlations between the relative abundances of genera and clinical features of kidney functions Fig.  and S3. Tannerella, found in the oral cavity and tonsilloliths, is associated with the production of volatile sulphur compounds and periodontitis42, which is linked to chronic kidney disease43. The correlation between a high abundance of Tannerella and decreased kidney function  might be related to periodontitis caused by this pathogen. Capnocytophaga is a core component of the microbiota in the oral cavity and palatine tonsil of HIV-infected individuals44. C. ochracea produces an immunosuppressive factor and degrades immunoglobulins46. These results highlight the potential relationship among the tonsil environment, tonsillar microbiota, and clinical features and suggest that the tonsillar microbiota contributes to kidney diseases, including IgAN.In addition, three genera with significant differences in relative abundance between healthy control or IgAN and disease control groups were correlated with eGFR, serum albumin, BUN, and plasma haemoglobin  and empty swabs. Despite these limitations, our results provide key insights into the tonsillar microbiota in IgAN, including correlations between taxon abundances and clinical features.Rahnella, Ruminococcus_g2, and Clostridium_g21 in patients with IgAN could be related to the immune status and pathogenesis of the disease. Further studies with larger sample sizes and systemic analyses of the gut microbiota and immunological features are necessary to understand the role of the microbiota in IgAN development.In conclusion, the microbiota in the tonsils of patients with IgAN differed from those of patients with other kidney diseases and healthy controls. The high relative abundances of 47. A histological evaluation was performed according to the Oxford classification48. Tonsil swab samples were collected by rubbing each palatine tonsil twice using a cotton swab . To check a potential contamination in cotton swab, empty swabs were also analysed along with tonsil swab samples. The samples were immediately stored at 4 °C, delivered to the laboratory within 24 h, and then stored at − 80 °C until DNA extraction.Patients who were admitted to undergo a kidney biopsy at three medical centres  in South Korea were enrolled. Patients were assigned to IgAN, DN, and MN groups based on the pathological evaluation. The DN and MN groups were used as disease control groups. Participants were enrolled at the time of kidney biopsy, before treatment with steroids or other immunosuppressants. Subjects who visited the Seoul National Boramae Medical Center for a regular health check-up and had normal kidney function and no underlying disease served as healthy controls. All subjects were over 18 years-old, and subjects who had undergone tonsillectomy were excluded. The demographic and clinical data for subjects were collected from hospital electronic medical records. The eGFR was calculated using the Chronic Kidney Disease-Epidemiology Collaboration equationThis study was approved by the Institutional Review Board of each centre  and performed in accordance with the principles of the Declaration of Helsinki. Informed written consent was obtained from each subject.50. Briefly, the V4-5 variable region of the 16S rRNA gene was amplified using extracted DNA, and amplification was performed according to the protocol for preparing a 16S metagenomics sequencing library using the MiSeq system . The first step of amplification was performed in a final volume of 50 µl containing 1 µM of each primer, 2.5 U Ex Taq polymerase , 5 µl of 10 × Ex Taq buffer, 4 µl dNTP mixture, and 2 µl template DNA using a C1000 Touch thermal cycler  under the following conditions: initial denaturation at 95 °C for 3 min; 25 cycles of denaturation at 95 °C for 30 s, annealing at 55 °C for 30 s, and extension at 72 °C for 30 s; and final extension at 72 °C for 5 min. The purification and size selection of amplicon were performed using Agencourt AMPure XP beads . The index PCR was performed using 5 µl of purified PCR product in a final volume of 50 µl using the Nextera XT Index Kit (Illumina) under the following conditions: initial denaturation at 95 °C for 3 min; 8 cycles of denaturation at 95 °C for 30 s, annealing at 55 °C for 30 s, and extension at 72 °C for 30 s; and final extension at 72 °C for 5 min. Purification and size selection were performed again using Agencourt AMPure XP Beads (Beckman Coulter). Negative controls (distilled water) were used at every step to check contamination, and the same experiments were performed for swab contamination controls. No amplicons were detected in negative controls and swab contamination controls. The quantification of library was performed using a PicoGreen dsDNA Assay Kit . Equimolar concentrations of each library were pooled and sequenced on the Illumina MiSeq System (250-bp paired-end reads) according to the manufacturer’s instructions.Metagenomic DNA was extracted from 80 swab specimens using a FastDNA SPIN Extraction Kit  according to the manufacturer’s instructions. For MiSeq sequencing, samples were prepared as described previously51. Sequence reads were merged, and reads with short lengths (merged reads of < 200 bp) or low-quality scores (Q < 25) and primer sequences were removed from the merged sequences using the USEARCH pipeline v.10.0.240 (https://www.drive5.com/usearch). Chimeric sequences were removed using the UPARSE tool. Resultant sequences were clustered into OTUs based on97% identity. Taxonomic positions of representative sequences in each OTU cluster were assigned using the EzTaxon-e database52. To compare diversity indices among samples, read numbers were normalised by random subsampling and indices were calculated using MOTHUR53. PCoA plots were generated to compare the microbiota among samples using Calypso54.Sequence reads were analysed using CLC genomics workbench v.11.0.1 with the Microbial Genomic Module  as described previouslyClinical characteristics of subjects were compared by analysis of variance (ANOVA) and chi-square tests. P-values < 0.05 were considered statistically significant. Permutation tests were used to calculate statistical significance in the PCoA. Differences in microbial taxa between samples were evaluated by the Mann–Whitney U test and Kruskal–Wallis test implemented in R. The correlations between clinical features and relative abundances of specific microbes were analysed using Spearman’s rank correlation tests in SPSS (version 22). Corrections for multiple testing were performed using the Benjamini–Hochberg method for false discovery rate adjustment. Results with corrected p-values of < 0.05 were considered statistically significant.Supplementary file1Supplementary file2Supplementary file3Supplementary file4Supplementary file5Supplementary file6Supplementary file7


Participation in aerobic and resistance training was assessed by a detailed questionnaire and BMI was calculated as weight (kg)/[height (m2)]. Pulse wave velocity and AIx were measured using an applanation tonometry before (pre), immediately after (post), and after 10 min (post10) of maximal exercise test. Cardiorespiratory fitness, PA, or BMI was not associated with PWV or AIx. Pulse wave velocity decreased significantly from pre to post10 among those in the highest third of CRF  and in normal weight participants , but not among those in the other thirds of CRF or overweight or obese participants. Participants who had regular resistance training had continuously higher AIx from pre to post10 than those who had no regular resistance training . In conclusion, exercise may decrease PWV and AIx. Our results suggest that positive arterial responses to exercise could be slightly improved in fit and normal weight individuals.We investigated the associations of cardiorespiratory fitness (CRF), physical activity (PA) with regard to aerobic and resistance training, and body mass index (BMI) with pulse wave velocity (PWV) and augmentation index (AIx) in middle‐aged adults with at least one cardiovascular risk factor. A total of 84 (46 men and 38 women) participated in the study. Cardiorespiratory fitness was measured using a maximal graded exercise test on a cycle ergometer and was defined as maximal power output (W Arterial stiffness and impaired arterial dilatation capacity are one of the first signs of cardiovascular diseases. We found that exercise may decrease arterial stiffness and improve arterial dilatation. Our study also suggests that cardiovascular responses to exercise may be improved in fit and normal weight individuals. All participants with diagnosed cardiovascular diseases were excluded. Prior to participation in the study, all participants were informed about the research purposes and measurement procedures and were screened by a cardiac specialist. A total of 84 (46 men and 38 women) had the complete data used in these analyses. The research protocol and study design were approved by the institutional review board of the Central Finland Hospital District ethical committee, Jyväskylä, Finland (Dnro 5U/2016). All study participants provided written informed consent prior to the inclusion in the study. The study was performed as stated by the Declaration of Helsinki.2.2A maximal exercise test was conducted on an electromagnetically braked cycle ergometer  utilizing a graded exercise test protocol with continuous ECG recordings  to assess the level of aerobic exercise capacity  defined as the workload at the end of the exercise test scaled by BW‐1 and allometrically scaled Wmax by BW‐0.35, because Wmax/BW‐1 had a strong inverse association with BW  = −0.782 to −0.392, p < .001) indicating that ratio scaling by BW‐1 was not able to remove the effect of body size on cardiorespiratory fitness. Therefore, allometric scaling of Wmax was performed by log‐linear regression models  suggesting the validity in scaling cardiorespiratory fitness for body size.We defined cardiorespiratory fitness as the maximal power output  which includes one tonometer and an integrated ECG unit  and augmentation index (AIx) as measures of arterial stiffness were measured before, immediately after, and 10 min after the maximal graded exercise test by a single trained researcher (EL) using a PulsePen device  waveforms in rapid succession at a sample rate of 1 kHz, and defined as the transit distance between the measuring sites divided by the time delay between the distal pulse and proximal pulse wave, using the ECG trace as reference. Transit distances were assessed by body surface measurements using a tape measure from the suprasternal notch to each pulse recording site . Direct carotid to femoral measurement was adjusted to 80%  for the calculation of PWV as recommended by current guidelines. Transit time was defined as the difference between the delay of the distal pulse wave to the R wave belonging to the ECG qRs complex and the delay of the proximal pulse wave to the R wave belonging to the ECG qRs complex. The pulse wave delay was determined by calculating the time elapsed from the peak of the R wave and the “foot” of the pressure pulse wave.Augmentation index is another measure that has been used to describe central arterial stiffness but AIx also reflects peripheral arterial tone. Changes in AIx in response to exercise may reflect arterial dilatation and opening of peripheral arterial tree. AIx was obtained from the carotid pressure waveform analysis. AIx is a parameter which provides an indication of the contribution of reflected waves to the total pulse pressure and was defined as the difference between the second and first systolic peak on arterial pulse waveform and was expressed as a percentage of central pulse pressure ((AIx)=augmented pressure/pulse pressure × 100).Supine brachial systolic blood pressure and diastolic blood pressure were obtained using an oscillometric Microlife BP A200 blood pressure monitor  for better sensitivity and accuracy. Two sequential readings were recorded, and the mean values were used. Participants rested in the supine position for 10 min before PWV was measured at baseline. However, due to the nature of the study, arterial stiffness was measured immediately and 10 min after the exercise test exposure without having laid supine for 10 min.The pressure values recorded by tonometry were calibrated to the blood pressure values obtained at the brachial artery; where they were assigned to the appropriate pixels and the values for mean arterial pressure and all other pressure‐related parameters were re‐established. The values deduced by the software apply the established concept that the mean arterial pressure remains unchanged in the tract from the aorta to the peripheral arteries. Mean arterial pressure was calculated by the software as diastolic blood pressure + 1/3(systolic blood pressure–diastolic blood pressure).2.5t test for normally distributed continuous variables, the Mann–Whitney U test for skewed continuous variables, or chi‐squared test for categorical variables. The associations of cardiorespiratory fitness and BMI with PWV, AIx, systolic and diastolic blood pressure, and mean arterial pressure were investigated using linear regression analyses adjusted for age and sex. Linear regression analyses were also used to investigate the associations of systolic and diastolic blood pressure, and mean arterial pressure with PWV and AIx. Differences in PWV and AIx between those who regularly engaged in aerobic or resistance training and those who did not were studied with ANOVA adjusted for age and sex. The associations of cardiorespiratory fitness, BMI, aerobic exercise, and resistance exercise with PWV were further adjusted for mean arterial pressure and those with AIx for heart rate . Basic characteristics between sexes were compared using Student's max/BW‐0.35 as a measure of cardiorespiratory fitness because it efficiently removed the effect of body size on cardiorespiratory fitness. We investigated the role of cardiorespiratory fitness as thirds, weight status , aerobic and resistance exercise , blood pressure (normotensive (systolic blood pressure < 120 mmHg and diastolic blood pressure < 80 mmHg), high (systolic blood pressure 120–129 mmHg and diastolic blood pressure < 80 mmHg), stage 1 (systolic blood pressure 130–139 mmHg or diastolic blood pressure 80–89 mmHg), stage 2 (systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg)  but inversely associated with PWV in men . Further adjustment for mean arterial pressure attenuated the association between Wmax/BW‐1 and PWV in men . In addition, cardiorespiratory fitness expressed as Wmax/BW‐1 was inversely associated with diastolic blood pressure after adjustment for age and sex. However, cardiorespiratory fitness was not associated with diastolic blood pressure when it appropriately expressed as Wmax/BW‐0.35.Cardiorespiratory fitness expressed as Wex Table . Furtherp = .036 for sex interaction), but the differences between women  or men  who resistance trained and those who did not were not statistically significant. Further adjustment for mean arterial pressure augmented the differences in men , but it had no effect on the differences in women (data not shown). Participants who resistance trained had higher AIx than those who did not . This difference remained statistically significant after further adjustment for heart rate. There were no other statistically significant differences between aerobic or resistance training groups.Sex modified the associations of resistance training and PWV  and inversely with PWV in women . Further adjustment for mean arterial pressure strengthened the association in women  but attenuated it in men . Systolic blood pressure, diastolic blood pressure, and mean arterial pressure were directly associated with PWV and AIx  but was higher at post10 than preassessment (mean difference (pre vs. post10) = 0.258 m/s, 95% CI = −0.494 to 0.258, p = .043 for main effect).Pulse wave velocity decreased from pre‐ to post‐test . This difference was no longer statistically significant after further adjustment for age and sex (p = .462). Further adjustment for mean arterial pressure strengthened these differences (p for the main effect = 0.043), but the post hoc comparisons were not statistically significant. Additional analyses showed that PWV decreased significantly from pre to post10 only in the highest third of Wmax/BW‐0.35  after adjustment for age and sex.Cardiorespiratory fitness expressed as Wp = .084 for interaction, Figure p = .029) only in normal weight participants (p = .034 for the main effect). There were no differences in PWV among normal weight, overweight, and obese participants (p = .914 for the main effect). Additional adjustment for mean arterial pressure had no effect on these results.Weight status modified the effects of a maximal graded exercise test on PWV  and stage 2 hypertension .Resting blood pressure did not modify the exercise response on PWV  and post10 . Participants who were in the highest third of PWV at the preassessment had continuously higher PWV from pre to post10 than those the middle  and the lowest third . Further adjustments had no effect on these results.Pre‐PWV modified the effect of a maximal graded exercise test on PWV .AIx decreased linearly from pre to post10  and post  (p < .001 for the main effect). In overweight participants, AIx at post  and post10  were lower than pre‐exercise AIx. Similarly, in obese participants post  and post10  AIx were lower than pre‐exercise AIx. Further adjustment for heart rate had no effect on these results.Weight status partly modified the effect of a maximal graded exercise test on AIx  and post10  in participants who had regular resistance training. AIx at post was also higher than at post10 . Among those who had no regular training AIx at pre was higher than at post  and post10 . Furthermore, participants who had regular resistance training had continuously higher AIx from pre to post 10 than those who had no regular resistance training . This difference strengthened after adjustment for age and sex (p = .037). Further adjustment for heart rate had no effect on these differences. Aerobic endurance training did not modify AIx responses to exercise.Resistance training modified the response of AIx to a maximal graded exercise test (max/BW‐0.35, blood pressure, or PWV did not modify the response of AIx to a maximal graded exercise test and there were no differences in AIx between the thirds of Wmax/BW‐0.35, blood pressure groups, or thirds of PWV. The results on the associations of blood pressure with AIx remained similar when normotensive and elevated groups were combined.W4max/BW‐1 and diastolic blood pressure. However, this association attenuated when cardiorespiratory fitness was appropriately normalized for BM using allometry and expressed as Wmax/BW‐0.35. We also observed that a higher BMI was related to higher diastolic blood pressure and mean arterial pressure. Furthermore, PWV decreased among participants with higher fitness level and normal body weight in response to a maximal graded exercise with increasing workloads. Finally, we observed a slightly augmented AIx response to a maximal graded exercise test in normal weight compared to obese participants.The most consistent finding in our study was that a higher systolic blood pressure, diastolic pressure, and mean arterial pressure were strongly associated with higher PWV and AIx. We found no association of cardiorespiratory fitness or the level of exercise training with arterial stiffness or arterial tone in middle‐aged subjects with cardiovascular risk factors. Nevertheless, we observed an inverse association between cardiorespiratory fitness expressed as Wmax/BW‐1 was inversely associated with diastolic blood pressure. However, this association was no longer seen when the effect of body size on cardiorespiratory fitness was appropriately controlled using allometry. This observation suggests that the association between cardiorespiratory fitness and diastolic blood pressure was largely explained by differences in body size and composition.In contrast with the results of some previous studies showing an inverse association between cardiorespiratory fitness and arterial stiffness in children (Veijalainen et al., We found that regular aerobic endurance exercise was not associated with arterial stiffness. Previous studies have shown that aerobic exercise training can improve vascular functions (Green et al., We observed that BMI was related to diastolic blood pressure and mean arterial pressure, but not with arterial stiffness. Furthermore, in line with previous studies (Safar et al., A graded exercise with increasing workload had a small overall effect on PWV. However, we found that those participants with the highest cardiorespiratory fitness, normal weight, and those with the highest PWV demonstrated a slight decrease in PWV in response to a maximal graded exercise test. We also found a slight decrease in PWV in obese participants from pre to post, but PWV returned to pre levels within 10 min. These results may imply that individuals with higher cardiorespiratory fitness and normal weight can better regulate vascular function and blood conductance to match peripheral oxygen requirements. Previous studies have shown that sedentary individuals have blunted nitric oxide‐dependent vasodilatation that can be prevented by exercise (Black, Green, & Cable, Furthermore, obesity has been associated with impaired nitric oxide‐dependent vasodilatation (Higashi, Sasaki, Nakagawa, & Matsuura, The strengths of this study include a measurement of cardiorespiratory fitness using a maximal exercise test and valid and reproducible measures of arterial stiffness. We not only investigated cross‐sectional associations of cardiorespiratory fitness, BMI, exercise training, and blood pressure with arterial stiffness but also their role in the effects of a maximal graded exercise test, which is commonly used in clinical practice, allowing us to capture more comprehensive picture of determinants of arterial health. We also utilized allometric scaling to account the effect of body size on cardiorespiratory fitness. However, because we did not measure body composition in the present study, we were unable to normalize cardiorespiratory fitness for lean body mass which is considered the gold standard measure to remove the effect of body size and composition on cardiorespiratory fitness (Loftin, Sothern, Abe, & Bonis, In conclusion, our findings showed that elevated blood pressure was strongly related to increase arterial stiffness and tone. These results indicate that lowering blood pressure would have the largest effect on improving arterial compliance. Furthermore, we found that cardiorespiratory fitness, endurance or resistance training, or BMI were not associated with arterial stiffness. Acute graded exercise may decrease PWV and AIx and thereby improve cardiovascular health. Furthermore, a maximal graded exercise decreased arterial stiffness in individuals with higher cardiorespiratory fitness, normal weight, or higher pre‐exercise PWV but not in those with lower cardiorespiratory fitness or those who were overweight or obese. Therefore, the results of our study suggest that positive arterial responses to exercise could be slightly improved in higher fit and normal weight individuals. The role of these slightly augmented responses in future cardiovascular morbidity and mortality among normal weight individuals and those with higher fitness levels warrants further study.The authors declare no conflict of interest and have no financial relationship to disclose.Conceptualization; EAH, EL, and JAL; methodology and data collection: EL and JAL; writing—original draft preparation: EAH; writing—review and editing: EL and JAL. All authors have read and agreed to the submitted version of the manuscript.The datasets generated during and analyzed during the current study are available from the corresponding author on reasonable request.


Due to a critical shortage of available kidney grafts, most patients with Stage 5 Chronic Kidney Disease (CKD5) require bridging dialysis support. It remains unclear whether treatment by different dialysis modalities changes the selection and/or preparation of a potential transplant candidate. Therefore, we assessed whether the likelihood of receiving kidney transplant (both living or deceased kidney donors) differs between haemodialysis (HD) and online haemodiafiltration (HDF) in patients with CKD5D.Individual participant data from four randomised controlled trials comparing online HDF with HD were used. Information on kidney transplant was obtained during follow-up. The likelihood of receiving a kidney transplant was compared between HD and HDF, and evaluated across different subgroups: age, sex, diabetes, history of cardiovascular disease, albumin, dialysis vintage, fistula, and level of convection volume standardized to body surface area. Hazard ratios (HRs), with corresponding 95% confidence intervals (95% CI), comparing the effect of online HDF versus HD on the likelihood of receiving a kidney transplant, were estimated using Cox proportional hazards models with a random effect for study.n = 179) of patients who were treated with online HDF compared with 19% (n = 152) of patients who were treated with HD. No differences in the likelihood of undergoing a kidney transplant were found between the two dialysis modalities in both the crude analyse  and adjusted analysis for age, sex, diabetes, cardiovascular history, albumin, and creatinine . There was no evidence for a differential effect across subgroups based on patient- and disease-characteristics nor in different categories of convection volumes.After a median follow-up of 2.5 years (Q1 to Q3: 1.9–3.0), 331 of the 1620 (20.4%) patients with CKD5D received a kidney transplant. This concerned 22% (Treatment with HD and HDF does not affect the selection and/or preparation of CKD5D patients for kidney transplant given that the likelihood of receiving a kidney transplant does not differ between the dialysis modalities. These finding persisted across a variety of subgroups differing in patient and disease characteristics and is not affected by the level of convection volume delivered during HDF treatment sessions. Online HDF has been associated with a lower all-cause and cardiovascular mortality risk when compared with HD, especially for the patients receiving the highest delivered convection volume . The association between convection volume and likelihood of receiving kidney transplantation was adjusted for age, sex, baseline serum albumin, creatinine, history of diabetes and history of CVD. Complete case analyses were conducted given that the specific data for (time to) transplantation was almost complete (n = 1 missing). All analyses were performed using R (version 3.5.1.) and a two-sided p value of < 0.05 conferred statistical significance.A similar statistical approach as the original IPD meta-analysis has been followed . Hazard n = 151) and 20% (n = 180) of the patients included received a kidney transplant during follow-up, but in the French and Turkish studies these percentages were much smaller   underwent a kidney transplantation during a median follow-up of 2.5 years (Q1-Q3: 1.9–3.0 years). In the CONTRAST and ESHOL study, respectively, 21% (both 2%) .Patients who received a kidney transplant during follow-up were, on average, younger and had fewer comorbidities compared with those patients who did not receive a kidney transplant, but no differences by sex were found Table . PatientThe patients who received online HDF did not have a different likelihood of receiving a kidney transplantation compared with the patients receiving HD  Table . When ad2 BSA per session) were 1.15 (0.82–1.61), 1.02 (0.75–1.41) and 1.06 (0.80–1.40), respectively  and therefore not included in our main analysis. This might be explained by several factors related to either local healthcare policy, cultural differences, or patient characteristics and personal intention. For example, although the rate of kidney transplant per million inhabitants is higher in Turkey than the rest of Europe, this is largely caused by a higher rate of living kidney transplants . Given tMost of the previous studies on the likelihood of receiving a kidney transplant has focussed on the comparison of HD versus PD, and the role of HDF in access to transplantation has rarely been investigated. One meta-analysis of Wang et al., including six studies with 2727 patients, reported a borderline significant increase  in the likelihood of receiving a kidney transplant among patients treated with HDF compared to those patients treated with HD . HoweverWe were unable to examine post-transplantation patient and graft survival due a limited follow-up after transplantation (median time of follow-up post-transplantation: 24 months), limited number of post-transplantation events, and differences in transplantation rates between countries. The different effects between HD and HDF in terms of oxidative stress, immune function, and hemodynamic treatment tolerance, on the success of kidney transplantation remain an interesting area of research. There are multiple studies that have compared post-transplantation outcomes –41. Yet,The strengths of our study are that we analysed IPD from the largest available set of RCTs and made appropriate adjustment for measured and unmeasured confounders. Consequently, we produced the most reliable evidence on whether the likelihood of receiving a kidney transplant differed between HD and HDF for patients with CKD5D. However, our study is subject to some limitations. The four trials were not primarily designed to study the likelihood of patients receiving kidney transplants, since the primary end-point was mortality and differences between trials in terms of study design and methodology, and in- and exclusion criteria of patients remain. Therefore, we do not draw any causal conclusions in terms of renal transplantation and dialysis modalities. We explored these clinical differences in a wide range of subgroup analyses, which illustrated that our findings were robust for all explored factors, including patient characteristics and comorbidities. This might be limited by the fact that our study population consisted largely of European Caucasian patients. Finally, the average follow-up duration in the studies in our IPD dataset was approximately 2.5 years , while tIn conclusion, online HDF, compared with conventional HD, does not affect the likelihood of receiving a kidney transplant. This finding holds across a variety of important clinical subgroups and is not affected by the level of convection volume delivered during HDF treatment sessions.