The development of cardiovascular disease during renal impairment involves striking multi-tiered, multi-dimensional complex alterations encompassing the entire oxygen transport system. Complex interactions between target organ systems involving alterations of the heart, vascular, musculoskeletal and respiratory systems occur in Chronic Kidney Disease (CKD) and collectively contribute to impairment of cardiovascular function. These systemic changes have challenged our diagnostic and therapeutic efforts, particularly given that imaging cardiac structure at rest, rather than ascertainment under the stress of exercise, may not accurately reflect the risk of premature death in CKD. The multi-systemic nature of cardiovascular disease in CKD patients provides strong rationale for an integrated approach to the assessment of cardiovascular alterations in this population. State-of-the-art cardiopulmonary exercise testing (CPET) is a powerful, dynamic technology that enables the global assessment of cardiovascular functional alterations and reflects the integrative exercise response and complex machinery that form the oxygen transport system. CPET provides a wealth of data from a single assessment with mechanistic, physiological and prognostic utility. It is an underutilized technology in the care of patients with kidney disease with the potential to help advance the field of cardio-nephrology. This article reviews the integrative physiology and pathophysiology of cardio-renal impairment, critical new insights derived from CPET technology, and contemporary evidence for potential applications of CPET technology in patients with kidney disease. The patAs members of the scientific and health care community, we are challenged with an ethical and moral obligation to help reduce premature mortality from CVD in our growing CKD population. However, the challenge of helping to improve patient outcomes in this population is compounded by the highly complex processes involved in CVD development as kidney failure ensues. As renal function declines, the development of CVD involves both traditional and non-traditional risk factors such as uremia, pro-inflammatory cytokines, volume overload, mineral disorders, electrolyte disturbances, anemia, sympathetic nerve activation, renin-angiotensin-aldosterone (RAAS) activation and vitamin D deficiency. Additionally, emerging risk factors such as elevated fibroblast growth factor (FGF)-23, low Klotho levels, post-translational protein modifications, and gut derived uremic toxins have now been tightly linked with CVD development in CKD  Figure . CentralThe striking multi-tiered, multi-dimensional complexities of CVD development in CKD have challenged our diagnostic and therapeutic efforts. For example, imaging of single organs such as the heart by echocardiography or MRI does not adequately reflect the complex systemic processes that lead to cardiovascular impairment in CKD and is therefore insufficiently sensitive to accurately reflect cardiovascular health in this population. Despite huge scientific, economic and financial investment, many of our cardio-renal outcome trials in nephrology have yielded neutral results and have not demonstrated a treatment benefit . This maThe emergence of state-of-the-art Cardiopulmonary Exercise Testing (CPET) technology and its application to cardiovascular disease research in nephrology is one such alternative approach gaining significant traction. While only a handful of studies have applied CPET technology to study patients with CKD, these studies have already revealed significant mechanistic and physiological insights, and have provided evidence to support the potential use of CPET-derived indices in a variety of applications in nephrology. This article considers integrative physiological and pathophysiological insights into cardiovascular impairment in CKD derived from CPET technology, and appraises contemporary evidence for the potential application of CPET to help advance the field of cardio-nephrology.As CKD progresses, the integrated metabolic machinery required for the cardiovascular system to function and enable optimal exercise performance is impaired. At the level of the heart and vasculature, kidney failure leads to a uremic phenotype that recapitulates many features of cardiovascular aging, including myocyte hypertrophy, reduced myocardial capillarization and non-vascularized myocardial interstitial fibrosis and calcification as well as vascular calcification, arteriosclerosis and arterial stiffening of systemic vasculature . The molCritically, CKD results in the failure of multiple organ systems beyond alterations to the heart and vasculature  Walsh, : The mus2) equals cardiac output multiplied by the arterial minus venous oxygen content, as illustrated in These diverse systemic alterations contribute to the impairment of the cardiovascular system to fulfill its primary function, that is, to be an effective oxygen transport system . The rol–1/kg–1 or one metabolic equivalent (MET). However, it has now become clear that resting cardiac and pulmonary function testing cannot reliably predict exercise performance and functional capacity, and that overall health status is more strongly associated with exercise tolerance than with resting measurements (2) at maximal or peak exercise (VO2Peak) as a robust, objective and reproducible index of cardiovascular functional capacity. While the definition of VO2Max and VO2Peak are different and will be discussed in further detail below, for the purposes of this article we will use the term VO2Peak . VO2Peak reflects the maximal ability of an individual to take in, transport and use oxygen and defines the individual’s functional aerobic capacity  is highly prevalent in the dialysis population and is associated with high rates of all-cause and cardiovascular mortality . However2 peak can occur in CKD. As an example, in advanced CKD patients, a reduction in maximal heart rate or a blunted chronotropic response occurs, leading to reduced cardiac output (2 – Cvo2max) , or conditions that affect the musculoskeletal system  and are too numerous to completely list here, but have also been described in bed-rest and deconditioning  . All patitioning .2uptake (VO2), carbon dioxide output (VCO2) and minute ventilation (VE) and some CPET systems, can provide breath-by-breath analysis of these variables. These measures are used to derive various other gas exchange patterns and can provide organ-specific information on the dysregulated responses to exercise. In the general heart failure population, CPET-derived indices have been recognized as robust markers for the assessment of cardiovascular disease compared to conventional resting imaging for several reasons. Firstly, the coupling of morphological cardiac alterations to cardiovascular performance is largely unknown; secondly, resting cardiopulmonary imaging tests cannot reliably predict functional performance; and thirdly, there is increasing appreciation that overall health status correlates better with exercise tolerance  is defined as the highest rate of oxygen uptake during intense, maximal exercise whereby no further increases in work rate can cause additional rises in VO2  (2 (VO2Peak) is directly reflective of VO2Max and is defined as the highest value of VO2 obtained upon an incremental or other high-intensity exercise test that brings the individual to the limit of tolerance (2Peak considers the integrative exercise response involving the degree of ventricular function (pumping capacity), oxygen transport in blood (O2 carrying capacity), pulmonary and vascular function (O2 delivery), skeletal muscle metabolic capacity (O2 utilization), and as well as ultrastructural and molecular changes of organ systems involved, and their interactions  at peak or incremental exercise (Maximum oxygen uptake (VOplateau) . Peak VOolerance . VO2Peakractions . During l effort . The perexercise . It is t2Peak declines by 10% per decade after the age of 30 and this has been attributed to decreasing maximal heart rate, stroke volume, blood flow to skeletal muscle and skeletal muscle aerobic potential  increasing linearly with VO2 and VCO2. This is followed by a second phase during which VE increases disproportionately relative to first VO2 and then VCO2  causes of exercise limitation . Above VT, however, progressive increases in VE result in the liberation of “excess” CO2 from bicarbonate stores. This helps to buffer the protons being produced as a result of high rates of glycolysis/glycogenolysis, but invalidates the use of RER as a measure of substrate oxidation. Nonetheless, RER still provides an objective descriptor of subject motivation. An RER greater than approximately 1.0 implies that an individual has attained a maximal volitional effort, whereas an RER less than this value suggests that they have not. Measurement of RER during CPET testing and is therefore of crucial significance to assist in the attainment of reliable and clinically meaningful VO2Peak values O2 (Oxygen pulse is the ratio between VOC(a-v)O2 . FlattenC(a-v)O2 . Under cC(a-v)O2 .2Peak (18 ± 4.1 ml/min–1/kg–1) compared to controls   . The stufunction . It is p2Peak) . These results become even more revealing considering that the study found that LV mass index did not change (p = 0.20). This highlights the limitations of using LV mass or hypertrophy as a surrogate endpoint for tracking disease progression in advanced CKD patients, and that other processes beyond LV geometric indices are likely involved in driving overall cardiovascular functional decline in this population.The CAPER  study by p = 0.003). Among the variables that were correlated with VO2Peak changes from baseline to 12 months in the non-transplanted dialysis group, were LV mass index, LV ejection fraction, and maximal heart rate as well as hemoglobin level (anemia). It is currently unknown how cardiovascular functional capacity alters with increasing dialysis vintage  beyond 1 year and this data will be critical to help inform cardiovascular risk. Additionally, it is unknown how processes such as myocardial remodeling through fibrosis, myocardial arteriole calcification, capillary rarefaction, myocardial stunning and complex circulating factors such as FGF23, Klotho and metabolites modulate VO2Peak decline in dialysis. We postulate that these factors may contribute to reduced cardiac compliance and ventricular contractility, loss of arterial elasticity, as well as end-organ damage of the lungs and skeletal muscle system. Further studies are needed to evaluate this.CAPER found that LV ejection fraction declined after 1 year . However, cardiovascular functional capacity was not restored to the level observed in the control group without CKD, and this was consistent with the incomplete normalization of kidney function with transplantation . These findings become all the more meaningful considering that LVMI did not change after kidney transplantation, despite a significant improvement in VO2Peak and when contrasted with the inverse direction of change in non-transplanted dialysis patients. Despite unaltered LVMI, the study reported an improvement in LVEF in the transplanted group at 12 months. These latter findings are consistent with a recent study using volume-independent cardiac magnetic imaging that failed to show significant change in LVMI and LVEF after transplantation  as well as corrected calcium level , lower peak heart rate  and impaired heart rate recovery  compared to patients with a GFR > 60. These findings are suggestive of subclinical cardiovascular disease that can be objectively assessed in pre-dialytic CKD patients. Given that microvascular dysfunction has been shown to be involved in cardiovascular disease in CKD and subclinical disease  functional class, worse symptoms, poor quality of life and decreased patient survival. Exercise capacity is reduced even in mild heart failure and is reflective of an inability of cardiac output to increase adequately with mild exertion . VO2Peakc output . In hearc output . Becausec output . Measurec output . The ide2Peak ≤ 14 mL.min–1.kg–1 as a criterion for which 1 year survival was significantly lower than that achieved through transplantation. Individuals with a VO2Peak > 14 mL.min–1.kg–1 had a 6% 1 year mortality and this suggests that heart transplantation can be safely deferred in this subgroup of symptomatic heart failure patients. VO2Peak potently risk stratifies heart failure patients (with reduced ejection fraction and preserved ejection fraction) into Weber classes A, B, C, and D corresponding to VO2Peak > 20, 16–20, 10–16, <10 mL.min–1.kg–1 which associate with 3 years transplant and mechanical circulatory support-free survival of 97, 93, 83, and 64% respectively . Significantly, among the patients who had VT < 40%, those that underwent kidney transplantation had a significantly better survival compared with the non-transplanted patients. Among the patients with VT ≥ 40%, survival did not differ significantly between those who were transplanted and those who were not. These results suggest that assessment of VT using CPET can provide a high level of discrimination to risk stratify patients for timely kidney transplantation, and that those with a VT < 40% may benefit from early transplantation. These findings are critical given the growing body of evidence that single surrogate markers from the most established clinicopathologic factors, such as age and LV mass index, have limited prognostic value for cardiovascular outcomes in CKD.CPET-derived indices of cardiovascular functional capacity have recently been shown to be robust predictors of cardiovascular morbidity and premature death among patients with advanced CKD, independent of LV measures , 2014. I2 uptake patterns and mechanical or musculoskeletal parameters. In the general heart failure population, a number of indices have been associated with important measures of cardiovascular physiology such as circulatory power (an index of cardiac systolic function), VE/VCO2 (an index of ventilatory efficiency and pulmonary vascular resistance) and mean response time  that can be easily attainable using CPET non-invasively (A significant strength of CPET is that the technology provides a wealth of data from a single assessment, including hemodynamics, ventilatory efficiency, stability and Ovasively . CPET as2 and arterial, as well as mixed venous blood gasses during linear ramp exercise. These data will allow Fick cardiac output derivation and evaluation of the component variables of the Fick equation. Patients with identical VO2Peak values with a diagnosis of heart failure, may have significantly different levels of impairment in the reserve capacity of each Fick variable (CPET that is coupled with invasive hemodynamic assessment, for example using radial or pulmonary arterial catheters enables highly detailed patient phenotyping. This permits accurate assessment of blood pressure and oxyhemoglobin measurement, as well as simultaneous measurement of VOvariable . No studThe significant public health need for better diagnostic and therapeutic approaches to help improve cardiovascular outcomes in CKD requires the implementation of effective, holistic and forward-thinking strategies in our research efforts. Given the multi-systemic nature of CVD development in CKD, an integrative approach at all levels to study mechanisms of disease, to track disease progression or improvement, for risk stratification, and for implementation of appropriate clinical trial endpoints maybe warranted. CPET provides a global test of cardiovascular functional capacity that reflects the entire oxygen transport system and may provide a potential solution for an integrative approach to assessing the cardiovascular system in CKD. The technology provides a wealth of data per single assessment with mechanistic, physiological and prognostic utility. Because a significant advantage of CPET is the ability to couple the technology with other investigative modalities such as invasive CPET and advanced imaging techniques, this can provide comprehensive phenotyping and characterization of multisystem changes that determine overall cardiovascular functional capacity with a wide array of applications. While CPET is a powerful technology, there are also important limitations to the technology that warrants a brief discussion. Firstly, CPET assessment does select for patients who retain some functional ability and therefore, patients who are unable to complete a cycle or treadmill test would be inherently excluded from assessment; Secondly, like all types of exercise testing, patients are required to present to a CPET lab and tests must be conducted by a trained exercise physiologist or clinician. Development of CPET technology has now enabled measurement of ventilatory parameters using handheld devices that can be used in an office-based setting, making the technology increasingly more accessible.Although CPET is a tool that is now widely available and supported by sound scientific evidence in several clinical fields, only a handful of studies have utilized CPET to study kidney patients. Despite this, CPET has already provided a wealth of hypothesis-generating data and has opened up many other exciting questions in the cardio-renal field. The potential to capitalize on next-generation CPET technology to help move the cardio-renal field forward has provided strong rationale for the urgent need for further CPET-related research in nephrology. Here in the Division of Nephrology at Indiana University School of Medicine, we have developed the first nephrology-based CPET laboratory in the United States dedicated to studying kidney patients. These efforts are in parallel with increasing interest among nephrologists worldwide in exercise impairment and musculoskeletal disorders in CKD patients. CPET technology has the potential to drive actionable strategies in our collective efforts to help reduce the burden of CVD in CKD. Strong efforts to recognize these promising advances and to place them as a primary research agenda in cardio-nephrology are needed.KL wrote the manuscript. GM generated all the figures. AC, GL, and SM provided the intellectual guidance and edited the manuscript. All the authors read and approved the manuscript.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.


Diabetic Retinopathy is one of the serious complications patients’ diabetic patients suffer from. Little is known about which risk factors are associated with this complication. The aim of this study was therefore to identify determinants of Diabetic Retinopathy in Jimma University Medical Center.A facility-based case-control study was conducted. Cases were Diabetic patients with diabetic retinopathy and who were on follow up at the Jimma University Medical Center while controls were Diabetic patients but free of diabetic retinopathy and who were on follow up at the Jimma University Medical Center. Cases and controls were identified and 311 of them were recruited using systematic random sampling. Data were entered into the Epi-Data version 4.1 and analyzed using SPSS Version 20. Binary Logistic regression analysis was conducted to identify determinants of diabetic retinopathy.A total of 106 cases and 205 controls diabetic participated in the study. Being ≥60 years of age ,being illiterate , poor adherence to medication ,having high systolic blood pressure , having family history of Diabetes Mellitus , having other micro vascular complications , poor glycemic control , poor cholesterol control  and being anaemic  were the independent determinants of diabetic retinopathy.This study found that poor adherence to medication, being at the age of 60 years and above, being illiterate patients, having high systolic blood pressure, having a family history of Diabetes Mellitus, having other micro vascular complication, poor glycemic control, poor cholesterol control and being anemic patient were the independent determinants of diabetic retinopathy. Therefore, more attention should be given to older age and illiterate patients. Giving more emphasis for patients poorly adhered to anti-diabetic medications and giving advice for diabetic patients with high systolic blood pressure to follow their blood pressure regularly are also vital. Diabetic patients should also control their Blood sugar and blood cholesterol levels to prevent diabetic retinopathy or reduce its further complications. Diabetic retinopathy (DR) is a neurovascular complication of both type1 and type 2 diabetes, which strongly correlates to both the duration of diabetes and the level of glycemic control. It is the major long-term complication of diabetes and the main cause of vision impairment and vision loss. Diabetic retinopathy is a primary cause of visual injury in working-age adults [. Evidence showed that DR is responsible for 4.8% of the 37 million cases of blindness due to eye diseases throughout the world [Diabetic retinopathy is the specific micro-vascular complication of Diabetes Mellitus (DM) and affects 1 in 3 persons with DM [he world .A Global meta-analysis study done in US, Australia, Europe and Asia reported that 1 in 3 34.6%) had any form of diabetic retinopathy [% had anyWHO reported that a good controller of diabetes and hypertension significantly reduces the risk for diabetic retinopathy . Major rIn Ethiopia, around 2.1 million people are suffering from diabetes, of which 4.8% of adults are living with diabetes and 39% of these 2.1 million people are additionally suffering from DR [A facility based case control study was conducted in the Jimma University Medical Center (JUMC), the specialized hospital in Southwest of Ethiopia. The study was conducted from March 10 to May 09, 2018. The Hospital is located in Jimma City, . The hospital gives health services for more than 10 million people living in Southwest Ethiopia. The hospital has chronic follow-up clinics for both pediatric and adult patients. The diabetes clinic runs twice weekly and provides integrated diabetic care for both Type 1 and Type 2 diabetics for about 70–90 patients per day. In the hospital, there were around 3020 diabetic patients who follow regularly their treatments of which 946 patients were with DR and around 1605 of the patients were free of DR.In this study, a case was defined as a diabetic patient with any of the following characteristic lesion: micro aneurisms, or hemorrhage, or hard exudates, or venous beading and new vessels on retina  and controls (n = 1605) were identified using the aforementioned case and control definitions. The sampling frame (list) of cases and controls was prepared systematic random sampling technique was used to select cases and controls for final data collection. Cases were selected from diabetic retinopathy patients and controls from free of retinopathy diabetic patients by systematic random sampling from ever enrolled diabetic patients on diabetic follow-up as a sampling frame. The kth value in the systmetaic sampling procedure for both case and control was calculated by diving each source population by the total sample size. For control the kth value was 5 and the 4rth patient was selected by using lottery method, then data was collected from every 5th patients starting from the 4th patient free of diabetic retinopathy by systematic random sampling. Similarly the kth value for the case was 3 from the list of 1 to 3 DM patient, the 2nd patient was selected by using lottery method, then data was collected from every 3rd patients starting from the 2nd patient with diabetic retinopathy by systematic random sampling.Sample size was determined using EpiInfo statistical software version 7 using the following assumptions of two population proportion formula for the unmatched case-control studies: high baseline diastolic blood pressure (was taken as main exposure variable as it gave maximum sample size compared to other exposure variables) , 5% leveAn interviewer-administered questionnaire was used to collect data from participants using the local language (Afan Oromo language). The questionnaire was developed after reviewing different kinds of literature , 12–17  using calibrated digital weighing scale at a precision of 0.1 kg as per recommended but not repeated measurements. Height was measured using a stadiometer in centimeter (cm) in an erect position that the back of the head, shoulder blades, buttocks, and heels make a contact with the backboard at a precision of 0.1 cm with shoes removed as per recommended but not repeated measurements. Blood pressure was measured using a mercury sphygmomanometer with a cuff deflation rate of 2 mmHg. Two measurements were taken from left arm while the participant was in sitting position. Five minutes between each measurement was maintained to take avoid measurment bias. Cholesterol level was taken from the patient’s folder near to the time of data collection and if not present in the folder, 4 ml of the whole blood sample was taken and sent to the laboratory for both cases and controls. Hemoglobin was taken from the patient’s folder near to the time of data collection and if not present in the folder, 1 ml of the whole blood sample was taken and sent to the laboratory for both cases and controls. Operational definitions. Adherence to medication was defined as “if the patients took all his/her anti-diabetic medication in last seven days before the study” while adherence to blood glucose testing at home was defined as “if the patient measured his blood glucose for at least once every week [Alcohol consumption history was defined as “if the patient reported consumption of any type of alcoholic beverages within the past 12 months were considered as alcohol consumers [Glycemic control was measured by random blood sugar. Average of the random blood sugar level of the last three records was used to define glycemic control. Any diabetic patient whose blood glucose measurement above 200 mg/dl was considered as good glycemic control while any diabetic patient whose blood glucose measurement 200 mg/dl and below was considered as poor glycemic control. Adherence to diet was assessed from report of particiapant wether he/she has followed recommended diet. If the patient followed the recommended diet forr more than 3 days in last seven days before the study period, that participant was labeled as adherent otherwise not adherent.inopathy . Weight ery week , 20”. Alp-value < 0.25 were considered for final multivariable logistic regression analysis using the Backward Likelihood ratio method. Crude Odds ratios (CORs) and Adjusted Odds ratios (AOR) with their respective 95% CIs were computed for each exposure variable. P-value < 0.05was used to declare statistical significance and exposure variables with p-value < 0.05 were considered as determinants of DR. Model goodness of fit was checked using the Hosmer Lemeshow test of goodness of fit , omnibus likelihood test < 0.05(0.000) with 89% model accuracy.The collected data were edited, coded and entered into Epi-Data version 4.1 and then exported to SPSS 20 for analysis. Descriptive statistics  were computed. Exposure variables associated with DR were identified using bivariate logistic regression analysis. Exposure variables with A total of 311 (97.8%) (106 cases and 205 controls) of DM patients who were on follow up in the Jimma University medical center participated in the study. The mean age (±Standard deviation) for the cases and the controls were 59.08 (SD: ±9.25) and 42.42 (SD: ±13.95) respectively. About two third, 65% of the cases and 60.9% of controls, were male participants. More than half, 52% of cases and 56.6% of controls were from rural residential. The majority of the cases (59.4%) and most of the controls (87.8%) were literate. Of those cases, 27.4 and 72.6% were government employees and self and private businesses respectively, but from the controls 20.5 and 79.5% were government employer and self and private business respectively  of cases and 62.9% controls adhered to meal instructions. From all study participants, 62 (58.5%) of cases and 166 (80.9%) of controls adhered to blood glucose measurement at home (Table More than nine-tenths 93.4%) of the cases and more than half (60.5%) of the controls were type II diabetic patients. There was a family history of DM in 56 (52.8%) of cases and 64 (31.2%) of controls. About half (48.1%) of the cases and less than one tenth (9.7%) of controls had a history or diagnosed as having other micro-vascular complications like heart and renal diseases. In this study, 41 (38.7%) of the cases and about one-tenth (9.3%) of controls had systolic hypertension, whereas 49 (46.3%) of cases and about one fourth (23%) of controls had diastolic hypertension. The proportion of poor glycaemic control was 63.2% in cases and 20% in controls. More than half (56.2%) of cases and more than one fourth (27.1%) of controls had also poor serum cholesterol levels. One third (32.4%) of cases and 8.7% of controls were anemic while 30 (28.3%) of cases and 59 (28.8%) of controls were overweight , poor adherence to medication, family history of Diabetes Mellitus, presence of other micro vascular complication, poor glycemic control, systolic hypertension, poor cholesterol level and being anemic patients were significantly associated with the development of diabetic retinopathy.The odds of developing Diabetic retinopathy were almost five times higher in patients with age 60 years and above than patients under 60 years of age . The study revealed that illiterate diabetic patients had about seven times higher odds of developing diabetic retinopathy than literates . Patients who did not adhere to medication were three times more likely to develop DR than diabetic patients who did not adhere to medication . The study also revealed that the odds of developing DR were more than three times higher for patients with baseline Systolic Blood Pressure level of 140 mmHg and above than their counters parts . The odds of developing DR were nine times higher in diabetic patients with poor blood glucose control than diabetic patients in good blood glucose control .The study also revealed that participants who had a family history of DM and who had other micro-vascular complications were about four times higher odds of developing DR than their counterparts ,  respectively. In the study, patients with poor cholesterol levels were about 79% times less likely to develop DR than diabetic patients who had a good serum cholesterol level . Diabetic patients who were anemic were more than two and half have times the odds of developing DR than their counterparts   was also one independent factor that determines the development of DR among diabetic patients. Similar findings were also reported in China , ArbaminThis study revealed the presence of other micro vascular complication was another determinant of diabetic retinopathy. The finding is consistent with the study done in high-risk China population  that revThe limitations of this study were behavioral variables like adherence to diabetic care, blood pressure, cholesterol, and hemoglobin level, were collected from patient records. These data may not show the measurements prior to the development of DR. On the other hand, the possibility of information bias especially on alcohol consumption history, smoking history, adherence to diabetic care and wide confidence of random blood glucose control could affect the validity of and precision of the study. Even though measurement for weight and height were taken by health professionals, a single measurement may not be accurate, measurement bias could affect this study.The findings in this study shows that older age of 60 years and above, lack of proper educational, poor adherence to anti DM medication, being born from having family history of DM, presence of other microvascular complication like renal problem and heart diseases, poor blood glycemic control level, having systolic hypertension, poor serum cholesterol level and being anemic patients were significantly associated with the development of diabetic retinopathy. Therefore, there is a need to give attention by supplying necessary logistics, assigning trained health professionals and necessary training for who lacks proper trainings for different health professionals who could treat diabetic patients. Similarly, there is a need to consider older age patients, and creating good awareness to have optimal adherence to medication, especially for illiterate patients. Moreover, early identification and prompt management of patients with other micro-vascular complications are vital. Patients adherence to physicians’ advice and provided medication is also crucial.Additional file 1. Questionnaire to assess determinants of Diabetic Retinopathy


The presence of either of these two risk factors can better reflect the condition of the donor than previous classification. However, on their last follow-up creatinine and estimated glomerular filtration rate values in those with or without these risk factors were not significantly different. For an ECD with a B2MG level of <7.18 and no history of RRT, kidney transplantation can be undertaken without considering the possibility of kidney discard.Kidney transplantations using expanded criteria donors (ECD) are being increasingly adopted, but no consensus tools are available to evaluate donor kidney status. Beta-2 microglobulin (B2MG) is a marker of kidney function, and herein, we evaluate the usefulness of assessing B2MG to evaluate donor kidney status. Fifty-seven kidney transplantations were performed from March 2017 to April 2019. Medical records were retrospectively reviewed, and relationships between clinical and laboratory variables and transplant outcomes were investigated. Thirty-eight patients received a standard criteria donor kidney and 19 patients an ECD kidney. Ten patients experienced delayed graft function (DGF), but no patient experienced primary nonfunction. Of the parameters studied, only donor renal replacement therapy (RRT) [odds ratio (OR) 24.162;  Renal replacement therapies such as dialysis or kidney transplantation (KT) are considered proper management options for patients with severe CKD or end-stage renal disease (ESRD), and KT is considered a better choice than dialysis in many respects3. Furthermore, as demand for KT increases, so does interest in the prognosis of patients with transplanted kidneys in terms of quality of life and cost-effectiveness.Chronic kidney disease (CKD) is becoming a major global health issue because of its prevalence and economic cost. Societal aging and the associated increases in the prevalence of hypertension and diabetes inevitably mean that the number of CKD patients will continue to increase5, but this has also inevitably increased discard rates6. Even patients fortunate enough to have undergone KT may experience primary nonfunction, delayed graft function (DGF), or rejection, and frequently, these conditions eventually result in poor graft outcomes or early graft failure. Furthermore, these conditions have been associated with prolonged hospitalization, higher costs, and mortality8.It is practically impossible to provide KT to all indicated patients due to donor shortages. To overcome this situation, kidneys from expanded criteria donors (ECDs) or donors after cardiac death (DCDs) have been used worldwideMany clinical and laboratory risk factors have been evaluated in attempts to predict the status of donor kidneys, but discard and DGF rates have not substantially changed. Accordingly, we considered the possibility of using novel predictors of kidney status and focused on assessing donor beta2-microglobulin (B2MG) serum level. It has been reported that the ability of serum B2MG to predict renal failure in the general population and CKD patients is unaffected by sex, age, or race. Also, the estimated glomerular filtration rate (eGFR) and calculated serum B2MG level have been reported to reflect renal function well. However, donor serum B2MG has not been evaluated in the context of the association between transplant outcomes and ECD and DCD kidneys.p = 0.523). The numbers of donors that received renal replacement therapy (RRT) in the SCD and ECD groups were 6 (15.8%) and 1 (5.3%), respectively (p = 0.405). Initial creatinine (Cr), final Cr, highest Cr values, urine and serum cystatin C, and urine and serum B2MG levels were not significantly different between the two groups. The baseline characteristics of donors in the two groups are displayed in Table Of the 57 recipients, 38 (66.7%) received a standard criteria donor (SCD) kidney and 19 (33.3%) an ECD kidney. Gender ratios and body mass indices (BMIs) were similar in the SCD and ECD groups. The frequency of acute kidney injury (AKI) > grade 2 was 11 (28.9%) in the SCD group and 4 (21.1%) in the ECD group (p = 0.469). Rates of biopsy-proven rejections were also similar. However, last follow-up median Cr (1.09 mg/dL) and eGFR (68.5 mL/min) were better in the SCD group than in the ECD group  . Baseline characteristics of recipients of SCD and ECD kidneys are shown in Table The demographic characteristics of the recipients, including age, gender, BMI, primary kidney disease, RRT type and duration before KT, were similar in the SCD and ECD groups, and the HLA mismatch and immunologic risk numbers, kidney weights, and cold ischemic times (CIT) were also similar. Ten recipients experienced DGF; 8 21.1%) in the SCD group and 2 (10.5%) in the ECD group  = 1.374 - 119.954] and donor B2MG level of ≥ 7.18 mg/L  were significant independent risk factors of DGF. Logistic regression analysis results are provided in Table Receiver operating characteristic (ROC) curve analysis showed donor final eGFR, highest Cr, serum cystatin C, serum B2MG level, and cold ischemic time significantly predicted DGF. Areas under curves (AUCs) of parameters are displayed in Table vs.7, 50%; p = 0.001). All living donor kidney recipients belonged to the group without a risk factor. Laboratory parameters including initial eGFR, highest Cr, final Cr, and final eGFR were much better in the group without risk factors than in the group with risk factors, and the prevalence of DGF and biopsy-proven rejection were lower in recipients without a risk factor. However, recipient last follow-up Cr and eGFR values were similar in the two groups. A summary of the results is provided in Table Contrary to the traditional SCD/ECD classification, DGF developed more frequently in those recipients with a risk factor  in all nucleated cells, and under the above conditions, a large number of cells may be generated and shed B2MG25. Furthermore, brain death induces a profound inflammation reaction, which influences multiple transplantable organs and causes kidney tubular damage by generating cascades of activated cytokines27. Ischemic-reperfusion injury can induce similar events. B2MG is an indicator of systemic inflammation, but not of kidney status, and the outcomes and functions of transplantable organs are significantly influenced by inflammation reactions. Thus, B2MG status, which is strongly correlated with GFR and inflammation, may be a meaningful marker of transplantable organ function, including kidney function. Most B2MG is reabsorbed in proximal tubules, and thus, a high level of urinary B2MG indicates tubule damage25. However, Cooper et al.28 reported that acute tubular injury did not affect transplant outcome. In the present study, urinary B2MG was not predictive of DGF, and the urinary B2MG level was not different between the SCD and ECD groups. In a previous study, the effectiveness of serum B2MG level as a biomarker of adverse outcomes in CKD was investigated. In patients with ESRD or chronic allograft damage after renal transplantation, a previous study reported that compared to urinary B2MG level, serum B2MG level predicted kidney status more accurately25. However, there are no reports evaluating donor kidney status or predicting the incidence of DGF by assessing serum B2MG levels. Even though our study was conducted at a single institution and on a small number of patients, serum B2MG showed good predictive power for DGF with RRT, and it reflected the condition of donors more accurately than those derived by using the SCD and ECD classification approaches.In this study, we reviewed several risk factors believed to result in DGF. Of these, only donor RRT and B2MG were observed to be related to the development of DGF. Donor RRT means that the donor has a kidney with an AKI > grade 3 according to the Kidney Disease Improving Global Outcomes (KDIGO) definition. Even though many studies have reported that KT using an ECD with AKI have outcomes comparable to those using an ECD without AKI or SCD, subgroups that needed RRT or showed Cr level elevation showed poor outcomes29. If identification of DGF risk factors before transplantation were possible, recipient outcomes would be improved, and donors would have an additional incentive to prevent kidney discard. The therapeutic interventions used to prevent DGF have been widely investigated and reviewed. A recent Cochrane review showed that machine perfusion provides a better means of preserving donor kidneys than cold storage in terms of preventing DGF and improving outcome30. Modifications of immunosuppressant agents have been investigated, and the selection of induction agents is a well-debated issue. Rabbit anti-thymocyte globulin (rATG) produced better results than interleukin-2 receptor blockers in some studies32, but other studies produced contradictory results33. In the present study, rATG was used to a greater extent in the recipients with risk factors group, and its use was not associated with reductions in DGF and rejection rates. However, final creatinine and eGFR levels in the recipients with risk factors group were similar to those in the recipients without risk factor group despite the presence of DGF and rejection. Even though machine perfusion can produce better results, many institutions cannot use machine perfusion due to resource limitations. Thus, modulation of immunosuppressant agents may be a more realistic option in many situations.DGF is not an uncommon complication during the period immediately following transplantation and is associated with prolonged hospitalization, increased cost, and the possibility of graft failureIn conclusion, we increased the use of ECDs and DCDs to address donor shortage, which means we now attach greater importance to detecting patients at risk to prevent DGF and improve long-term outcomes. In this regard, it is important to find kidney function indicators that can be quickly and repeatedly assessed. Although our study was conducted on a small cohort at a single institution, the results show that if serum B2MG is <7.18 mg/L and therapeutic, and there is no history of donor RRT, KT from an ECD with AKI can be performed without the need to consider kidney discard.From March 2012 to July 2019, 135 patients underwent KT at Wonju Severance Christian Hospital, Wonju, South Korea, with all transplants performed by a single surgeon. B2MG samples were prospectively obtained beginning in March 2017, and the present retrospective study was performed using the data of 57 patients that registered from March 2017 to April 2019. This study was approved beforehand by the Institutional Review Board of Yonsei University Wonju Severance Hospital (CR318083). The requirement for informed consent was waived because of the retrospective nature of the study. All studies were conducted according to the principles of the Declaration of Helsinki. All living and deceased donors were evaluated for infections of hepatitis B or C virus  or human immunodeficiency virus (HIV) before transplantation. Transplantation was conducted in cases when donors did not show evidence of HBV, HCV, and HIV infections. All procurements and transplantations were performed by surgeons of our departments who were registered into Korean Network for Organ Sharing (KONOS), under the permission of KONOS. There is no procurement from prisoners.34. SCD, ECD, DGF, and acute AKI were defined as we described in a previous article13.Samples of blood and urine to assess serum cystatin C, creatinine, B2MG, and urine cystatin C levels were collected and evaluated one day before procurement of a deceased donor or living donor kidney. B2MG level was measured by enzyme-linked fluorescent assay (ELFA) using a Vidas analyzer . The eGFR was calculated using the Modification of Diet in Renal Disease four4-variable equationRecipients at immunologic risk were defined as those that had undergone a second or ABO-incompatible KT, had a panel reactive antibody level > 20%, or had received a kidney from a deceased donor with an AKI grade > 3.13 with the exception that corticosteroid administration was started as 500 mg of methylprednisolone followed by dose tapering as previously described13. We checked cytomegalovirus (CMV) and BK virus infection status repeatedly. CMV infection status was checked postoperatively at 1 day, 1 week, 1 month, and 3 months. The BK virus status was checked postoperatively every three months for 1 year and then every 6 months. If quantitative CMV and BK virus test results were positive, we performed qualitative tests. As needed, oral valganciclovir was used to treat CMV infection, and a reduced level of immunosuppressive agents was applied for BK virus treatment.When neither donor nor recipient had any risk factor, we chose basiliximab as the induction agent. Briefly, 20 mg of basiliximab were injected on the day of the operation and again at four days after surgery. However, when a recipient was deemed high immunologic risk, rATG was the induction agent and was administered at 4.5 mg/kg/day in the first three days. We used a triple regimen of tacrolimus, corticosteroid, and mycophenolate mofetil as the maintenance immunosuppressant agents. Trough levels of tacrolimus and mycophenolate mofetil dosage were controlled as we previously describedThe baseline characteristics of SCDs and ECDs were compared and their effects on transplantation outcomes were investigated. Because there was no case of primary nonfunction, we performed analysis to identify risk factors for DGF. We also compared recipient baseline characteristics were compared and transplantation outcomes analyzed according to the absence or presence of risk factors.t-test, respectively. Cut off values of factors predictive of DGF were determined by performing receiver operating characteristic (ROC) analysis. Variables significantly associated with DGF were identified by univariate logistic regression analysis. Multivariate analyses were performed using the logistic regression analysis posterior Wald test.Statistical analyses were performed using SPSS Ver. 25.0 . Continuous variables are presented as medians and ranges, and categorical variables as numbers and percentages. Categorical and continuous variables were compared using Fisher’s exact t test and the


Patients with kidney transplantation often have a worse quality of life than the general population. One of the reasons for this, in male patients, is the high prevalence of erectile dysfunction. This is mainly due to the presence of comorbidities, surgery for kidney transplantation, adverse drug effects, psychological changes related to chronic disease, as well as hyperprolactinemia and hypogonadism. Whenever these endocrine dysfunctions occur after kidney transplantation, they must be corrected with appropriate treatment, i.e., testosterone replacement therapy. Administration of the phosphodiesterase-5 inhibitor (PDE5i) sildenafil at the recommended posology does not significantly alter the pharmacokinetics of the calcineurin inhibitors cyclosporin A or tacrolimus and does not impair kidney allograft function. Tacrolimus increases the peak concentration and prolongs the half-life of PDE5i in kidney transplant patients and, therefore, daily administration cannot be recommended due to the significant drop in blood pressure. Intracavernous injection or topical application of alprostadil can be a second-line option for the treatment of erectile dysfunction after kidney transplantation, which does not alter cyclosporine concentrations and does not deteriorate kidney function. Finally, penile prostheses can be successfully implanted following pelvic organ transplantation after eliminating the risk of infection associated with surgery. Impaired sexual function is very common in end-stage renal disease (ESRD) patients, with a prevalence of 60–90% in both genders ,2,3. AltIn a systematic review and meta-analysis of 50 studies, the rate of erectile dysfunction (ED) in patients with chronic kidney disease (CKD) was shown to be 75%, whereas it decreased to 59% in kidney transplantation recipients (KTRs). This suggests that restoration of the glomerular filtration rate (GFR) after transplantation may improve erectile function, although the reduction in ED severity and prevalence might depend on the predominant etiological mechanism . The higThe availability of published data that can be used to compare pre- and post-transplantation erectile function, as well as to evaluate the response to treatments, is very limited. Moreover, the main limitations of these studies are their reliance on a small number of patients investigated and the suboptimal or lack of uniform assessment of the outcome measures. In the present article, we perform a Medline search in the attempt to review the most important clinical and experimental lines of evidence on the main factors influencing the onset of ED after renal transplantation or their persistence/improvement after dialysis interruption. Furthermore, because of the paucity of the studies, we aim to highlight the best practice in the treatment of ED in KTRs, underlying that sexual dysfunction is an underestimated topic by nephrologists in both men and women with CKD, also after kidney transplantation.In KTRs, ED has a multifactorial etiology since either organic, psychological, or mixed abnormalities are involved . PredispDysfunctions of the hypothalamic–pituitary–gonadal (HPG) axis play a crucial role in the pathogenesis of ED . In partMoreover, the duration of hemodialysis before transplantation, a lower diastolic blood pressure, and peripheral arteriopathy can also influence ED in KTRs . After tEducation displays an inverse correlation with ED, which may be explained by less attention to healthcare, quality of life, and sexuality in people with low education . The rolThe duration of the hemodialytic treatment, which patients have undergone before kidney transplantation, also affects erectile function in KTRs ,16,20. IDrugs such as immunosuppressant and antihypertensive agents are involved in the onset of ED in KTRs. In particular, calcineurin inhibitors (CNIs), i.e., cyclosporine, tacrolimus, mTOR inhibitors, as well as corticosteroids, may impact on the endothelial function ,14,16,17Surgical procedures during transplantation, such as the interruption of iliac artery distal ends, may sometimes cause insufficiency of penile blood flow, leading to ED ,20. The Finally, psychological factors such as self-esteem, altered body image perception, worrying, anxiety, and depression (which are related to kidney disease and transplantation) usually affect erectile functioning ,22. IndeThe goals of immunosuppressive therapy in KTRs are to prevent graft rejection and complications and to reduce morbidity. KTRs are maintained on an immunosuppression regimen that includes one to three drugs. The major immunosuppressive agents used in these patients are CNIs, cyclosporin A (CsA) and tacrolimus, mammalian target of rapamycin—mTOR—inhibitors (sirolimus and everolimus), antimetabolites , and glucocorticoids (prednisone) .Nowadays, CNIs constitute the cornerstone of the immunosuppression regimen following kidney transplantation . HoweverAlthough vascular pathology represents the key mechanism underlying ED, it has been reported that testosterone deficiency may affect erectile function . SeveralRecent advances have elucidated the crucial role of mTOR in the male reproductive potential . HoweverNo data are available to assess whether everolimus is more or less gonadotoxic than sirolimus. Interestingly, it has been reported that the side effects on spermatogenesis, as well as on sex hormones, may be reversible by switching from the administration of mTOR-inhibitors to other immunosuppressants . ImmunosTogether with tacrolimus, antimetabolites  prevent the proliferation of T- and B-lymphocytes and represent the cornerstone of immunosuppressive therapy in KTRs. Although no data have demonstrated that antimetabolites may affect erectile function, some studies have reported that mycophenolic acid may negatively impact reproductive health. Indeed, it alters DNA synthesis through indirect mechanisms , leadingA wide variety of treatments to restore erectile function are safe and effective in KTRs. PDE5 inhibitors (PDE5is) have been studied in these patients, and, among them, sildenafil ,64,65,66As far as hormonal treatment goes, previous studies have found a positive correlation between the hormonal profile of KTRs and sexual function, confirming that the normalization of post-transplantation prolactin and testosterone levels yields several benefits, as well as shifting drug administration, as shown in Second-line treatments are penile injections and urethral suppositories. Intracavernous injections of alprostadil have been successfully used in immunosuppressed KTRs without any reports of kidney impairment or changes in CNI levels attributable to this treatment for ED . AlprostThird-line therapy includes penile implants, which should be carefully considered in these patients, taking into account the following aspects: (i) stable graft function for at least 6 months; (ii) low doses of immunosuppressants; (iii) low probability of device malfunction; (iv) no intra-abdominal components to avoid confusion of the reservoir with the bladder in the event of subsequent kidney transplantation; (v) minimum tissue dissection; (vi) no skin or urinary tract infections; (vii) use of prophylactic antibacterials ; (viii) treatment with post-operative broad-spectrum oral antibacterials for 1–2 weeks .Low-intensity shockwave therapy (Li-SWT) has recently emerged as a potential treatment for ED, and this has created considerable excitement due to its potential reparative mechanisms promoting the formation of new blood vessels and improving endothelial function in the corpora cavernosa. Yamaçake and colleagues have published promising results of the effects of six treatment sessions, with 7 out of 10 patients in the treatment group experiencing an improvement of at least 5 points in the IIEF-5 score vs. only 1 out of 10 in the sham group . At firsA pioneering clinical experience evaluated the effectiveness of vacuum therapy in dialysis patients, with 73% achieving erection with the vacuum device. In this study, all hypogonadal men received testosterone therapy via implantation of depo-testosterone . In the Although 38% of patients with testosterone deficiency display sexual symptoms, including ED, the latter does not usually correlate with the presence of hypogonadism in male KTRs . RemarkaThe incidence of ED in patients with ERSD and KTRs is quite high, and its management is particularly difficult due to many interfering factors. The first approach should refer to changing the pharmacological interference scenario, especially for those drugs upsetting sexuality at the central  and peripheral levels by shifting some adverse treatments to favorable ones whenever possible. The second approach may be to prescribe a PDE5i at a low dosage, considering that if testosterone-circulating levels are compatible with the diagnosis of hypogonadism, its efficacy may only be partial . The pos


Serum creatinine, urinary protein, and blood pressure were measured at baseline and after 8 weeks, at which point the rats were examined for glomerular injury and fibrosis. PAI1 mRNA levels were also evaluated. After 8 weeks, blood pressure, serum creatinine, and urinary protein levels were significantly higher in the high‐salt group than those in the normal‐salt group. Serum creatinine and urinary protein were significantly lower in both tadalafil groups than those in the high‐salt group, while only high‐dose tadalafil affected blood pressure. In addition, glomerulosclerosis and α‐smooth muscle actin expression significantly decreased in both tadalafil treatment groups. PAI1 mRNA increased significantly in the high‐salt group but decreased in both tadalafil‐treated groups. Our results indicated that both low‐ and high‐dose tadalafil prevented fibrosis and glomerular injury in a chronic kidney disease rat model. Mechanistically, these effects may be associated with PAI1 expression and glomerular structure protection.Phosphodiesterase 5 inhibitors are widely used to treat erectile dysfunction and lower urinary tract symptoms with benign prostatic hyperplasia. Recent studies have indicated the renoprotective effects of this class of compounds. Whether renoprotection depends on blood pressure reduction remains controversial. In this study, we investigated the renoprotective effects of the phosphodiesterase 5 inhibitor, tadalafil, in a rat model of high‐salt induced kidney injury with hypertension. Dahl salt‐sensitive rats were fed a normal diet, high‐salt (8% sodium chloride) diet, or high‐salt diet with oral administration of either low‐ or high‐dose tadalafil (1 and 10 mg kg A PDE5 inhibitor, Tadalafil is renoprotective by preventing glomerular injury and fibrosis from high blood pressure. This study suggest that Inhibition of PDE5 might be effective to delay the CKD progression. An NS + TH (10 mg kg−1 day−1) group was treated using the same protocols  were housed in a room with controlled temperature, humidity, and a 12 hr light/dark cycle with free access to normal water. We divided the rats into the following four groups  at 0 and 8 weeks. Briefly, rats were warmed at 37°C in an animal holder and kept for approximately 30 min to calm. BP was measured three times and the mean was calculated. Metabolic cages were used for 24 hr urine collection at 0 and 8 weeks. In addition, blood samples were acquired from the tail vein at week 0 and from the inferior vena cava under 2% of isoflurane anesthesia at week 8. The kidneys were harvested following euthanasia. The two halves of the right kidney were used for histopathological assessment and electron microscopy. The cortex and medulla of the left kidney were separated and analyzed using real‐time polymerase chain reaction (PCR). All animal procedures were approved by the Ethics Committee of Nagoya City University and performed according to the guidelines of the National Institutes of Health Science of Japan (H29‐P‐05).2.2Blood and urine were collected at 0 and 8 weeks. Serum creatinine (SCr), blood urea nitrogen (BUN), and the urinary protein to Cr ratio (UPC) were determined to evaluate the kidney function using enzymatic methods for SCr and BUN, and enzymatic and colorimetric methods for UPC. Serum Na, Cl, and K levels and total urinary Na, Cl, and K excretion over 24 hr were determined using the ion‐sensitive electrodes method. All measurements were conducted by Fujifilm Monolith Co., Ltd.2.3Briefly, total RNA was extracted from the kidney cortex and medulla using an RNeasy Mini Kit (Qiagen). RNA concentration and quality were measured using spectrophotometric analysis at 260 and 280 nm. A Rever Tra Ace kit  was used to reverse transcribe 1 µg total RNA to cDNA. Real‐time PCR was performed using a CFX Connect Real‐Time PCR Detection System  with KAPA SYBR FAST qPCR Master Mix . Relative expression levels were calculated using the ΔΔCt method with β actin as a reference. Primer sequences are listed in Table 2.4Kidney tissue was fixed in 10% of formalin for 2 days and placed in 70% of ethanol. The tissues were embedded in paraffin, and then, serially sectioned to 3‐μm thick samples. After deparaffinization and rehydration, the kidney sections were examined using periodic acid Schiff (PAS) and Azan staining.To evaluate the level of glomerulosclerosis, 30 glomeruli in each kidney were analyzed in PAS‐stained sections and graded as follows based on the severity of glomerular injury: grade 0, no sclerosis; grade 1, <25%; grade 2, 25% to 50%; grade 3, 50% to 75%; grade 4, >75%. The glomerulosclerosis index (GSI) was calculated using the following formula, which is widely used , as reported previously , dehydrated, embedded in Quetol 651 (Nisshin EM), and sectioned to 80–100 nm thickness. Tissue samples were subsequently stained with uranyl acetate and observed using a JEM‐1400Plus Transmission Electron Microscope (JEOL Ltd.).The kidney cortex was fixed with a mixture of 2.5% glutaraldehyde and 2% paraformaldehyde (Nisshin EM) in 0.1 M of phosphate buffer. Then, the tissue was washed, post‐fixed with 2% of osmium tetroxide .For scanning electron microscopy, samples were fixed with 2% of OsO2.6SEM. Comparisons were made using one‐way analysis of variance and Tukey's test. Data with a p < .05 were considered statistically significant.Data are expressed as the mean ± 33.1p < .01, Table There were no significant differences in body weight between the groups before or after the experiment Table . Serum e3.2Changes in kidney function parameters are shown in Figure 3.3p < .01, Figure Representative PAS‐stained glomeruli from each group are shown in Figure 3.4Transmission electron microscopy was used to observe the structure of the glomeruli, which consisted of endothelial cells, a glomerular basement membrane, and podocyte foot processes Figure . In the 3.5Figure 3.6PAI1 mRNA expression was significantly greater in the HS group than in the NS group Figure . The TL 4Our results demonstrate that tadalafil, a PDE5 inhibitor, had renoprotective effects in a CKD rat model. Antihypertensive agents, such as angiotensin‐converting‐enzyme inhibitors, angiotensin Ⅱ receptor blockers, and calcium channel blockers, are commonly used for renal dysfunction related to hypertension and are considered renoprotective for the amelioration of glomerular hyperfiltration. However, some of these agents are ineffective in improving proteinuria even with a reduction in BP (Takai et al., Moreover, the renoprotective effects of tadalafil may stem from enhanced protection of the glomerular structures against fibrosis. Tadalafil attenuated proteinuria caused by glomerular injury, diminished glomerulosclerosis, and maintained glomerular structure. The mechanisms underlying these effects of tadalafil remain to be elucidated, but PDE5 expression in the podocyte foot process has been previously reported Dousa, . PodocytFibrosis is a commonly observed pathological change during kidney dysfunction. Recently, PAI1 was shown to induce fibroblast activation and αSMA expression (Pincha et al., Our preliminary study revealed that a normal‐diet group treated with tadalafil did not show any differences in kidney function parameters relative to those in the NS group. This suggested that tadalafil suppressed or prevented renal dysfunction but did not enhance renal function. PDE5 is primarily expressed in smooth muscle cells, and thus, might be involved in renal hemodynamic regulation. The systolic BP was not affected by low‐dose tadalafil treatment. However, its effects on renal blood flow and glomerular hyperfiltration remain unclear. In this study, we used the tail‐cuff method to measure BP, which has low sensitivity. Thus, we cannot definitively conclude that the renoprotective effects of tadalafil were independent of its BP‐lowering effects. In fact, αSMA expression in the outer medulla, which is the most easily damaged by high BP‐induced stress, was obviously attenuated by tadalafil treatment. Further investigations of the mechanisms underlying the renoprotective effects of PDE5 inhibitors could create new therapeutic targets.There were some limitations to this study. First, different trends were observed in serum electrolytes between the TL and TH groups. The reason for this remains unclear, but it may be owing to variations among individuals at baseline. Ideally, the cutoff value used would have been set at the onset of the experiment. However, this does not challenge the observed renoprotective effects of tadalafil. Second, PDE5 inhibitors can have adverse effects, which should be considered. Clinically, tadalafil can cause a sudden and pathological decrease in BP (Kloner et al., 5We have demonstrated that tadalafil has promising effects on CKD with high‐salt‐induced hypertension and that mechanistically, these effects may be associated with the regulation of PAI1 and myofibroblast levels and the protection of glomerular structures. This suggests that PDE5 inhibitors may help to prevent the progression of CKD with hypertension and other complications into ESKD.N.T., Y.H., K.K. conceived and designed the study; N.T., Y.H., A.N., K.H., Y.M., S.T., contributed for the acquisition of data. N.T., Y.H., T.K., analyzed the data; N.T., Y.H., A.N., S.T., K.K. drafted the article; N.T., Y.H. revised the manuscript for intellectual content; N.T., Y. H. approved the final version of the paper. All authors approved the manuscript and agreed to be accountable of the manuscript.Table S1Click here for additional data file.


Glycosylated hemoglobin (HbA1c) was the best indicator of glycemic control, which did not show the dynamic relationship between glycemic control and lipid profiles. In order to guide the health management of Type 2 diabetes (T2D), we assessed the levels of lipid profiles and fasting plasma glucose (FPG) and displayed the relationship between FPG control and lipid profiles. We conducted a cross-sectional study that included 5822 participants. Descriptive statistics were conducted according to gender and glycemic status respectively. Comparisons for the control of lipid profiles were conducted according to glycemic control. Four logistic regression models were generated to analyze the relationship between lipid profiles and glycemic control according to different confounding factors. The metabolic control percentage of FPG, triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) was 27.50%, 73.10%, 28.10%, 64.20% and 44.80% respectively. In the fourth model with the most confounding factors, the odds ratios (ORs) and 95% confidence intervals (CIs) of TG, TC, LDL-C and HDL-C were 0.989 , 0.862 , 0.987  and 2.173 . TC and HDL-C were statistically significant, and TG and LDL-C were not statistically significant with adjustment for different confounding factors. In conclusion, FPG was significantly associated with HDL and TC and was not associated with LDL and TG. Our findings suggested that TC and HDL should be focused on in the process of T2D health management. The primary task of health management in Type 2 diabetes (T2D) patients is to prevent diabetes-related complications. Previous studies have shown that good control of lipid profiles and glycemic levels can effectively prevent complications such as cardiovascular disease, diabetic nephropathy and diabetic retinopathy ,2. LipidAlthough many studies have confirmed the relationship between glycemic control and lipid profiles in patients with T2D, the results are quite inconsistent ,10,11. KIt is certain that the relationship between glycemic control and lipid profiles in T2D patients is a major problem that needs to be solved urgently. HbA1c was used as an indicator of glycemic control in most previous studies ,14. HbA1The subjects in this study were from the Multicenter Longitudinal Health Management Cohorts in Shandong province, China, which included a total of 15,369 patients from T2D Health Management System of Huangdao District Center for Disease Control and Prevention, Qingdao, China. The T2D health management system was established in 2009 in Huangdao District, Qingdao City. A total of 15,369 T2D patients were included in the management system by July 2015. The number of patients entering the health management system in 2009, 2010, 2011, 2012, 2013, 2014 and 2015 were 1457, 65, 57, 493, 102, 12,318 and 877 respectively. According to the inclusion criteria, patients aged 18 years or older were included, while they must have complete demographic and clinical data. Exclusion criteria were an age younger than 18 years, pregnant women, breast feeding, malignancies, and autoimmune diseases. The 15,369 T2D patients who entered the health management system had met the above inclusion and exclusion criteria. Due to the absence of information related to demographic and clinical variables, a total of 5822 participants was included in the final analysis. This study was approved by the Ethics Committee of the School of Public Health, Shandong University (Code NO.: 20140322).2 (m). Duration of T2D was calculated as entry time minus diagnosis time of T2D. Laboratory tests included TG, TC, LDL-C, HDL-C, and FPG. Fasting blood samples were taken from the T2D patients and the serum was separated from the blood in a centrifuge tube. The serum samples were tested within two hours or frozen at −20 °C until testing. FPG was measured using the hexokinase method or the glucose oxidase method. The enzymatic method was used to measure TG and TC. HDL-C and LDL-C were measured using the direct test method. Automatic biochemical detectors  were used to test the concentration of TG, TC, HDL-C, LDL-C, and FPG.During the T2D patient’s entry into the management system, trained interviewers administered a standardized questionnaire to obtain demographic characteristics, including age, gender, current smoking status (yes or no), current alcohol intake , marital status (yes or no), educational level , and regular exercise frequency . After an overnight fast of at least 12 h, all subjects underwent a standardized medical examination that included routine anthropometric, clinical, and laboratory tests. The anthropometric measurements involved height, weight, SBP, and DBP. Two blood pressure values were taken about 10 min apart on the right arm by trained examiners using a mercury sphygmomanometer. Height and weight were measured after the participants had removed their shoes, heavy clothing, and belts. Body mass index (BMI) was calculated as weight (kg)/heightFPG < 7.0 mmol/L and FPG ≥ 7.0 mmol/L were defined as good glycemic control and poor glycemic control, respectively.According to Standards of medical care for T2D in China 2019 , the conHypertension was defined as an SBP ≥ 140 mmHg or a DBP ≥ 90 mmHg or the self-reported current use of antihypertensive medication .M) and quartile range (Q) based on the skewed distribution. The categorical variables were expressed as number and percentage. Various characteristics were compared between the glycemic control group and uncontrolled group. Mann–Whitney U tests were used to test the difference of the continuous variables and ordinal variables. χ2 tests were adopted to test the difference of categorical variables. Comparisons using χ2 tests for the control of lipid profiles  were conducted according to glycemic control. Logistic regression analyses were further performed to estimate the odd ratios (ORs) and 95% confidence intervals (CIs) of good glycemic control. Four logistic regression models were conducted to analyze the relationship between lipid profiles and glycemic control according to the adjustment for different confounding factors. In the four logistic regression models, the outcome variables were whether FPG  was controlled. Our main covariates of interest were TG, TC, HDL-C, and LDL-C. The four lipid profile variables entered the logistic model as numerical variables. No confounding factors were adjusted for in the first model; age and gender were adjusted for in the second model. In the third model, the adjusted confounders were extended to include age, gender, smoking, alcohol drinking, marital status, educational level, and physical exercise frequency. Compared with the third model, BMI, hypertension, duration of T2D, and antidiabetics were further added to the fourth model. SPSS 23.0 software  was used to perform all statistical analyses.Descriptive statistics were conducted according to gender and glycemic control status respectively. The numerical variables were described as the median (A total of 5822 subjects were included in this study, which included 2188 males and 3634 females. The characteristics of the subjects were summarized in T2D patients had an increased risk of death and disability due to associated complications, suggesting the significance of good control for lipid profiles and glycemic level . TherefoIn this study, the control rates of FPG, TG, TC, HDL-C, and LDL-C for all T2D patients were 27.50%, 73.10%, 28.10%, 64.20%, and 44.80% respectively, with especially lower control rates for FPG and TC in T2D patients. A study from Beijing, China, showed a glycemic control rate of 30% . FurtherMoreover, the results of this study showed that the T2D patients with an FPG value ≥ 7.0 had a significant increase in TC and a significant decrease in HDL-C, rather than TG and LDL-C, compared with the T2D patients with an FPG value < 7.0. Prospective studies confirmed that lower HDL-C was not only associated with future high incidence of T2D ,27, but Similar to our findings, Mullugeta Y et al. reported that HbA1c was positively associated with TC while not with LDL . HoweverUnlike our findings, some studies have shown that T2D patients with an HbA1c value ≥ 7.0% have a significant increase in TC and LDL-C without significant changes in TG and HDL-C compared with the T2D patients with an HbA1c value < 7.0% . A studyOf course, FPG and lipid profiles levels of T2D patients are affected by many factors. The relationship between glycemic control and lipid profiles may be related to lipid-lowering agents used in T2D patients . Some liDifferent from previous studies that have used HbA1c as an indicator of glycemic control, in this study FPG was used as an indicator of glycemic control. Undoubtedly, HbA1c is the best indicator of glycemic control rather than FPG. However, HbA1c did not show glycemic variability over a period of time . ChangesOur research had several limitations. First, due to the lack of some information, a large number of T2D patients were lost, which may be biased. Second, lack of information on diet, medication, and comorbidities in patients with T2D may also have an impact on the results. Third, the laboratory tests of T2D patients were not in the same hospital, which may also affect the results.This study assessed the relationships between FPG control and lipid profiles in T2D patients in Qingdao, China. Our results showed that FPG was significantly associated with HDL and TC and was not associated with LDL and TG with adjustment for different confounding factors. Our findings suggested that TC and HDL should be focused on in the process of T2D health management.


Remote imaging photoplethysmography (iPPG) senses the cardiac pulse in outer skin layers and is responsive to mean arterial pressure and pulse pressure in critically ill patients. Whether iPPG is sufficiently sensitive to monitor cutaneous perfusion is not known. This study aimed at determining the response of iPPG to changes in cutaneous perfusion measured by  Laser speckle imaging (LSI). Thirty-seven volunteers were engaged in a cognitive test known to evoke autonomic nervous activity and a Heat test. Simultaneous measurements of iPPG and LSI were taken at baseline and during cutaneous perfusion challenges. A perfusion index (PI) was calculated to assess iPPG signal strength. The response of iPPG to the challenges and its relation to LSI were determined. PI of iPPG significantly increased in response to autonomic nervous stimuli and to the Heat test by 5.8% (p = 0.005) and 11.1% (p < 0.001), respectively. PI was associated with LSI measures of cutaneous perfusion throughout experiments (p < 0.001). iPPG responses to study task correlated with those of LSI  and were comparable among subjects. iPPG is sensitive to autonomic nervous activity in volunteers and is closely associated with cutaneous perfusion. Besides the recently proposed vital microscopy of the sublingual circulation2, the cutaneous microcirculation is a useful “body window to the circulation” and may indicate global perfusion deficits early in critical illness by clinical signs like skin mottling or prolonged capillary refilling6. Remote imaging photoplethysmography (iPPG) is an emerging technique that allows to sense cardiovascular signals in the outer skin layers7. The absorption and reflection of light at the skin is altered by local hemodynamic incidents, most importantly the cardiac volume pulse transmitted into the cutaneous and subcutaneous tissue. Minute fluctuations of the reflected light carry certain physiological information like heart rate and respiratory rate and can be read by conventional cameras. The ability of iPPG to measure these parameters remotely and to detect atrial fibrillation, for example, has been proved in numerous clinical settings11.Monitoring tissue perfusion is a pivotal concern in critically ill patients13. Owing to the penetration depth of light, this specific behaviour is restricted to the haemodynamic background in the cutaneous microcirculatory network. iPPG thus selectively targets the peripheral cutaneous circulation. Of special interest is the two-dimensional high-resolution signal pattern of iPPG. It yields a perfusion intensity map rather than a single spot measurement allowing a deeper investigation of cutaneous perfusion characteristics like density, heterogeneity and spread.iPPG also has been shown to be sensitive to haemodynamic conditions beyond heart rate. To an individual extent, its signal intensity instantly responds to changes of pulse pressure and mean arterial pressure15. A varying light absorption by haemoglobin due to the cutaneous blood volume pulse is considered the key mechanism16 and indicates the sensitivity of iPPG for cutaneous perfusion. Besides, ballistocardiographic optical surface phenomena17 and mechanisms that are not directly mediated by cutaneous blood volume are suggested18. The actual association of iPPG signals to the peripheral perfusion is therefore unknown.The emergence of iPPG signals is however still far from clearIn this study we investigated the relationship of the iPPG to cutaneous perfusion. To this end, we compared iPPG signals to laser speckle imaging (LSI), a reference measure of cutaneous perfusion, in volunteers exposed to various stress situations that evoke autonomic nervous activity.The study protocol was approved by the Institutional Review Board of the TU Dresden . Thirty-seven volunteers participated in the study . Written informed consent was obtained from all participants. Participants who are shown in pixelized photos have given their explicit permission. All experiments were performed in accordance with the applicable guidelines and regulations.Baseline and experimental measurements comprised simultaneous recordings of iPPG video, Laser Speckle contrast imaging and reading of a reference photoplethysmogram  of two minutes duration. iPPG videos were recorded by an industrial-standard CMOS camera  at 25 frames per second, a resolution of 960 × 600 pixel and a 12 bit colour depth. Measurements were made under usual indoor fluorescent lighting. Videos were processed offline for iPPG analyses. The green color channel with a wavelength between 520 and 550 nm was evaluated. Laser speckle contrast images (LSI) for reference measurements were made by the moorFLPI-2 Laser Speckle Contrast Imager . The Laser speckle contrast imager employed a coherent light with a wavelength of 785 nm.Participants were lying in supine position throughout the experiments. Cameras and laser speckle imager were positioned nearly perpendicularly to the ROI (region of interest) on the forehead. The recording distance (patient face to device) was approximately 40–45 cm for laser speckle and 70–80 cm for the cameras. This setup was chosen as tradeoff between recording a sufficient large area from almost equal angles (perpendicular) and doing the record at a close distance. Both, iPPG videos and LSI recorded the upper facial area including the forehead.The experimental protocol was designed to prompt a weak thermoregulatory and autonomic nervous activity bypassing major haemodynamic reactions. To this end, a modified Stroop colour-word test and a deliberate Heat test were applied.19. Briefly, one of the colour words “MAGENTA”, “CYAN”, “BLUE”, “RED” or “GREEN” was displayed in the middle of a screen and participants had to quickly select the colour in which the word was printed from a list on the left side of the screen. Tests were performed as a congruent Stroop with matching colour and meaning of the target word as well as an incongruent Stroop where both did not match  circulated by water pre-heated at 38 °C.After baseline recordings of iPPG-video, LSI and reference PPG, participants underwent the Stroop test. Congruent and incongruent tests were alternately sequenced per subject. Each part had a duration of two minutes. Immediately after each Stroop test, measurements were taken. Following a recovery period of five minutes a measurement was taken and subjects thereafter underwent the Heat test. Further measurements were done 10 min as well as 20 min after the beginning of the Heat test . As feature, the mean flux value (Flux) was used . Laser speckle data thus did not require any preprocessing as the feature extraction was readily provided by the device. The reference finger PPG was evaluated in terms of the perfusion index like iPPG and denoted as reference-PI.μx denotes the mean value of x and σx its standard deviation) and then evaluated in mixed effects models (R Version 3.6.1.22) with individual subjects set as random effect. The responses of PI and Flux to the study interventions were defined as the difference to their respective baseline values. The variances of PI and Flux both at the individual level and between-subject level were estimated from the null model.Values of PI, Flux and reference-PI throughout the study are given as mean ± standard deviation in arbitrary units (au). Data were z-transformed at their grand mean 23. A proportional variance reduction at both, the individual and between subject level was calculated24.The effects of Flux on PI at the respective study tests were estimated in an analysis of covariance including flux and study test. Random coefficient models were used to investigate the individual variability of flux effects on PI. The explanatory performance of Flux as a source of PI was estimated by its coefficient of determination . PI significantly increased after both Stroop tests (congruent or incongruent) and during the Heat tests. Increases of PI ranged from 5.2% to 5.9% (Stroop tests) and from 10.1 to 11.8% (Heat tests) . In the analysis of covariance including Flux and study tests, these changes in PI were only determined by Flux. An independent effect of experimental tasks was not identified (p = 0.207). Apart from the recovery phase, where a slightly higher ratio of PI to Flux was found, the association of both variables was not affected by the study intervention. Despite the pronounced baseline variability of PI, the immediate effect of Flux on PI was comparable among subjects, a significant slope variance has not been proved . Flux explained a total of 45.3% of the variation of PI with a proportional variance change of 40.0% at subject level and 50.0% at inter-subject level.Subjects’ individual PI significantly increased with higher Flux . This relationship varied at the respective study interventions (p < 0.001 for the interaction with study intervention). While no significant association of the PI response to the Flux response was observed at the congruent Stroop test, this was found for the remaining experiments  following cardiac ejection are considered the key source of the plethysmographic signal detectable in the light reflection at the skin surface26 without major volumetric alterations. In addition, the light absorption and scattering coefficients in superficial skin layers are affected by pulsation-induced compression of the cutaneous tissue, thereby prompting fluctuations in the light reflection at the skin surface and contributing to the iPPG waveform14. Another source of the pulsatile light reflection are ballistocardiographic optical phenomena (BCG) strictly occurring at the skin surface as a result of whole body micromovements and superficial tilting27, but without any optical interaction within the tissue.The BVV effect is challenged by optical processes not directly linked to blood volume. The photoplethysmographic waveform is partly mediated by blood vessel wall movement, red blood cell (RBC) orientation and RBC aggregation/deaggregation29. Along with haemoglobin as the main light absorber in this spectral range in the dermis28, these features make up the functional basis for the plethysmographic representation of the cutaneous blood volume pulse. Although the pulsatile capillary pressure31 and velocity profile of erythrocytes32 are unlikely to exert a true blood volume effect in a single capillary due to the rigid nature of these vessels33, these phenomena underline the blood volume variation in their feeding vessels of the upper horizontal network. Whether the varying number of perfused capillaries per heartbeat essentially influences the iPPG remains to be investigated.The significance of BVV for the origin of iPPG is supported by physiological and experimental data. According to a cutaneous penetration depth of approximately 1 mm, iPPGs based on green light comprise local haemodynamics in capillary loops and the upper horizontal arteriovenous network of the papillary dermis34. The modulation of light absorption by haemoglobin along with BVV is therefore seen as a key effect. An adapted Lambert–Beer model was applied to explain this mechanism35.An intrinsic effect of the cutaneous haemoglobin amount on iPPG, and thus an association to cutaneous perfusion, is moreover emphasized by the peak signal strength of iPPG in the spectral range of the absorption maximum of haemoglobin36. Its optical background differs essentially from that of iPPG and in particular is not exposed to the effects of vessel wall movement, tissue compression or BCG. The significant relationship to LSI proved in this study therefore supports a predominance of cutaneous perfusion in the iPPG signal.LSI as a reference measure of cutaneous perfusion is based on a reduction of speckle contrast by the number as well as the velocity of moving blood cells and semiquantitatively assesses tissue blood flow37. Moreover, a cold face test in volunteers provoked marked changes in the iPPG signal even in entirely different body regions, indicating that systemic vasoactive events can be detected by iPPG38. Likewise, a capsaicin induced release of calcitonin gene-related peptide, known to be a potent vasodilator in the cutaneous microcirculation39, led to a more than two-fold increase of the iPPG signal amplitude in healthy adults and migraine patients40. Interestingly, iPPG was also found to indicate distinct migraine-associated blood flow changes40.Recent studies on volunteers and patients affirm the association of iPPG to cutaneous perfusion. The local iPPG signal amplitude is significantly increased by the cutaneous vasomotor response to a circumscribed thermal impact41. It is to be noticed that the results of the current study confirm a concordance of iPPG with tissue perfusion even after a systemic and non-local vascular response of much lesser degree.In a study comparing iPGG to Laser Doppler imaging (LDI) during local vasodilation after the application of a liniment or local heat, PI of iPPG and LDI-derived cutaneous blood flow multiplied almost identically and correlated closelyThe presented study has some limitations. The far higher variance of PI among subjects, as compared to the intrinsic PI variance, has to be considered in signal analysis and evaluation. Its intraclass correlation and variance structure are comparable with those of the reference measure. Even with this parameter structure, a systematic variability of PI per subject in response to the study tasks was demonstrated. In parallel, the comparable response to Flux changes despite markedly different baseline levels of iPPG points to a consistent physiological basis of iPPG among subjects. This is an essential feature for iPPG as a monitoring device, especially in view of the intrinsically widely different PI values.38. However, further research is needed to clearly explain the behavior of iPPG during vasoconstriction, especially when it is associated with a decreased organ perfusion in critical disease.This study focused on the effects of peripheral vasodilation on iPPG. A significant response of iPPG to physiologically triggered vasoconstriction also has been demonstrated in volunteersThe recording distance of approx. 40–45 cm between laser speckle and face slightly exceeds the recommended working distance of up to 38 cm. According to preliminary tests during experimental setup LSI did not show much differences in its applied configuration compared to a slightly closer application. Moreover, LSI meets the physiological expectation, suggesting that this distance has not compromised the results.iPPG might fulfill the requirements for assessment of peripheral perfusion in critically ill patients. iPPG has not yet been compared with clinical parameters of peripheral circulation, nor has it been thoroughly evaluated in patients with circulatory disorders. Its contribution to the detection of cutaneous perfusion deficits in the critically ill therefore remains to be investigated in dedicated clinical settings. The optimal iPPG parameters for the clinical estimation of perfusion deficits are subject to further research. Especially, the analysis of the two-dimensional dynamic perfusion maps opens up new perspectives for the evaluation of spatial perfusion parameters like density, heterogeneity and spread.iPPG is sensitive to autonomic nervous reactions in volunteers. iPPG’s signal intensity and its response to autonomic nervous reactions are closely explained by cutaneous perfusion.Supplementary file1