Renin-angiotensin system activation: may it increase frequency of obstructive sleep apnea in patients with autosomal dominant polycystic kidney disease?

PURPOSE: Renin-angiotensin system (RAS) hyperactivity is a common entity in both autosomal dominant polycystic kidney disease (ADPKD) and obstructive sleep apnea (OSA). We aimed to investigate the frequency of OSA in adults with ADPKD either with stages 3-4 or stages 1-2 chronic kidney disease (CKD) and evaluate the effect of RAS blockade on OSA in these patients. METHODS: This is a comparative, prospective, two-center clinical study. Eligible patients with ADPKD were enrolled in a polysomnography (PSG) study. Presence of OSA in patients with ADPKD was compared with individuals who underwent polisomnography study due to OSA symptoms. A subgroup analysis was performed in terms of the presence of OSA in ADPKD with eGFR values lower or higher than 60 ml/min/1.73 m2 (stages 3-4 and stages 1-2 CKD, respectively). RESULTS: Frequency of OSA (65%) was higher than in the general population and similar between the two groups (p = 0.367). Patients with ADPKD and eGFR ≥ 60 ml/min/1.73 m2 presented a similar frequency of OSA to the control group (p = 0.759). However, OSA was significantly more frequent in ADPKD with eGFR < 60 ml/min/1.73 m2 (p = 0.018). Subgroup analysis revealed that presence of OSA also was significantly higher in ADPKD with lower eGFR levels (eGFR < 60 ml/min/1.73 m2 and eGFR > 60 ml/min/1.73 m2) 14/17 (82%) and 12/23 (52%), respectively (p: 0.048). CONCLUSION: As kidney disease progresses, uremia and related factors of renal failure rather than RAS activation seem to play a more important role for the development of OSA in patients with ADPKD.

Clinical predictors of incipient vertebral fractures and bone mineral density in kidney transplant patients.

PURPOSE: Kidney transplant recipients are prone to metabolic bone diseases and consequent fractures. This study aimed to evaluate the incidence of incipient vertebral fractures, osteopenia, osteoporosis, and the clinical factors associated with incipient vertebral fractures in a group of kidney transplant patients. METHODS: Two hundred sixty-four patients (F/M 124/140, 45.3 ± 13 years) who had undergone kidney transplantation in tertiary care centers were included. Vertebral fractures were assessed semiquantitatively using conventional thoracolumbar lateral radiography in 202 of the patients. RESULTS: Vertebral fractures were observed in 56.4% (n = 114) of the study group. The frequency of osteoporosis was 20.0% (53 of 264 patients), and osteopenia was 35.6% (94 of 264 patients). Bone mineral density (BMD) levels were in the normal range in 40.3% (n = 46) of the subjects with vertebral fractures. It was in the osteoporotic range in 20.1% (n = 23) and the osteopenic range in 40.3% (n = 46). Vertebral fractures were associated with age, duration of hemodialysis, BMI, and femoral neck Z score (R2 37.8%, p = 0.027). CONCLUSION: As incipient vertebral fractures can be observed in patients with normal BMD levels in kidney transplant recipients, conventional X-ray screening for vertebral fractures may be beneficial for a proper therapy decision of metabolic bone disease in kidney transplant recipients.

COVID-19 in kidney transplant recipients: A multicenter experience in Istanbul.

INTRODUCTION: Management of COVID-19 in kidney transplant recipients should include treatment of the infection, regulation of immunosuppression, and supportive therapy. However, there is no consensus on this issue yet. This study aimed to our experiences with kidney transplant recipients diagnosed with COVID-19. MATERIAL AND METHODS: Kidney transplant recipients diagnosed with COVID-19 from five major transplant centers in Istanbul, Turkey, were included in this retrospective cohort study. Patients were classified as having moderate or severe pneumonia for the analysis. The primary endpoint was all-cause mortality. The secondary endpoints were acute kidney injury, the average length of hospital stay, admission to intensive care, and mechanical ventilation. RESULTS: Forty patients were reviewed retrospectively over a follow-up period of 32 days after being diagnosed with COVID-19. Cough, fever, and dyspnea were the most frequent symptoms in all patients. The frequency of previous induction and rejection therapy was significantly higher in the group with severe pneumonia compared to the moderate pneumonia group. None of the patients using cyclosporine A developed severe pneumonia. Five patients died during follow-up in the intensive care unit. None of the patients developed graft loss during follow-up. DISCUSSION: COVID-19 has been seen to more commonly cause moderate or severe pneumonia in kidney transplant recipients. Immunosuppression should be carefully reduced in these patients. Induction therapy with lymphocyte-depleting agents should be carefully avoided in kidney transplant recipients during the pandemic period.

A randomized study to assess the efficacy of herbal product to prevent cisplatin-induced nephrotoxicity in a rat model.

OBJECTIVES: This study aimed to investigate the protective effect and antioxidant activity of an herbal product that made from multiple plants in a rat model of kidney dysfunction induced by intraperitoneal cisplatin. MATERIALS AND METHODS: Twenty-four rats were divided into four different groups namely: Group 1 - control healthy animals without any specific medication, Group 2 - Herbal product only 5 mg/kg, Group 3 - cisplatin only and Group 4 - Herbal product 5 mg/kg + cisplatin. RESULTS: Evaluation of our findings demonstrated a significant (p = 0.017) reduction in Catalase activities and a significant increase (p = 0.001) in renal tissue Malondialdehyde levels in cisplatin- treated rats when compared with the control group. Also, Glutathion and Glutathione peroxidase content revealed significant (p = 0.031) reduction in renal tissues of cisplatintreated rats compared with the control group. Pre-treatment of rats with the herbal product ameliorated these cisplatininduced changes of the antioxidant enzymes. No statistically significant changes were demonstrated in Superoxide dismutase activities in the tissue specimens of any group. CONCLUSIONS: This potent antioxidant herbal medicine was found to have potential antioxidant activity, which may in turn to be effective in the protection of kidney tissue resulting from cisplatin application. Therefore, much attention should be given to the possible role of natural dietary antioxidants for protecting the kidney.

Association between serum pregnancy-associated plasma protein-A and bicarbonate in hemodialysis patients.

BACKGROUND: Acidosis is associated with protein-energy malnutrition, inflammation, and bone disease, and low bicarbonate levels have been implicated in higher mortality rates in chronic kidney disease. Recently, the concentration of serum pregnancy-associated plasma protein-A (PAPP-A) has become accepted as a prognostic marker in hemodialysis patients. This study determined the relationship between PAPP-A and bicarbonate levels in these patients. METHODS: The study enrolled 65 hemodialysis patients (41 males, 24 females) and 26 control subjects (11 males, 15 females). Serum PAPP-A, intact parathormone (iPTH), calcium, phosphorus (P), and bicarbonate levels were measured. Correlations between PAPP-A and bicarbonate, iPTH, calcium, and phosphorus were evaluated. RESULTS: Median PAPP-A levels were significantly higher in hemodialysis patients [15.1 (<0.03-158.8) ng/ml] than in control subjects [6.6 (<0.03-16.4) ng/ml] (P < 0.05). There were statistically significant correlations between serum PAPP-A and bicarbonate, iPTH, and P in hemodialysis patients but not in control subjects. CONCLUSION: Elevation of serum PAPP-A has been found in hemodialysis patients and its significant correlation with bicarbonate suggests that it may be a prognostic factor.

Prevalence of metabolic dysfunction-associated fatty liver disease in kidney transplant recipients: A cross-sectional study using FibroScan.

Background and Aim: Metabolic dysfunction-associated fatty liver disease (MAFLD) is expected to be prevalent among kidney transplant recipients (KTRs). In this study, we evaluated the prevalence of MAFLD among KTRs, data that have not been investigated by any clinical study to date. Materials and Methods: We included a total of 52 KTRs and 53 age-, sex-, and BMI-matched individuals as the control group through prospective consecutive recruitment. We detected the presence of hepatic steatosis and liver fibrosis using the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) defined by FibroScan. Results: Among the KTRs, 18 (34.6%) had metabolic syndrome. The prevalence of MAFLD among the KTRs and controls was 42.3% and 51.9%, respectively (p=0.375). The CAP and LSM values did not differ significantly between the KTRs and controls (p=0.222 and p=0.119). Among the KTRs, patients with MAFLD had significantly higher age, BMI, waist circumference, LDL, and total cholesterol levels (p<0.001, p=0.011, p=0.033, p=0.022, and p=0.029, respectively). In multivariable analysis, age was the only independent factor for MAFLD among the KTRs (OR: 1.120, 95% confidence interval (CI): 1.039-1.208). Conclusion: MAFLD among KTRs did not show a significantly higher prevalence compared to the normal population. Further clinical studies with larger populations are needed.

A prospective study of living kidney donors: 6 years follow-up from a cardiovascular disease risk perspective.

OBJECTIVE: The purpose of this prospective study was to evaluate the clinical, laboratory, and donation-specific outcomes of living kidney donors 6 years after donation. METHODS: We included a total of 93 kidney donors and 54 age- and sex-matched individuals as control group through a type 2 cohort consecutive recruitment. We detected kidney function abnormalities and the presence of hypertension, diabetes, and cardiovascular events during the 6 years follow-up period. RESULTS: The mean serum creatinine levels were higher (p<0.001), and the estimated glomerular filtration rate levels were lower (p<0.001) in living kidney donors 6 years after donation when compared with controls. The protein/creatinine ratio of the study population was also higher (p=0.014). There was no difference in outcomes between the groups for end-stage kidney disease and cardiovascular mortality. A higher rate of new-onset hypertension (6.4 vs. 32.9%), diabetes mellitus (0.0 vs. 4.3%), chronic kidney disease (0.0 vs. 2.1%), and cardiovascular disease (0.0 vs. 2.1%) was demonstrated among donors 6 years after donation (p<0.001, respectively). CONCLUSION: Our data have demonstrated that the reduction in Glomerular filtration rate induced by kidney donation might cause an increase in adverse renal and cardiovascular events.

Trends of primary glomerular disease in Turkey: TSN-GOLD registry report.

BACKGROUND: Although several renal biopsy registry reports have been published worldwide, there are no data on primary glomerular disease trends in Turkey. METHODS: Three thousand eight-hundred fifty-eight native kidney biopsy records were assessed in the Turkish Society of Nephrology Primary Glomerulopathy Working Group (TSN-GOLD) Registry. Secondary disease and transplant biopsies were not recorded in the registry. These records were divided into four periods, before 2009, 2009 to 2013, 2013-2017, and 2017-current. RESULTS: A total of 3858 patients (43.6% female, 6.8% elderly) were examined. Nephrotic syndrome was the most common biopsy indication in all periods (58.6%, 53%, 44.1%, 51.6%, respectively). In the whole cohort, IgA nephropathy (IgAN) (25.7%) was the most common PGN with male predominance (62.7%), and IgAN frequency steadily increased through the periods (× 2 = 198, p < 0.001). MGN was the most common nephropathy in the elderly (> 65 years), and there was no trend in this age group. An increasing trend was seen in the frequency of overweight patients (× 2 = 37, p < 0.0001). Although the biopsy rate performed with interventional radiology gradually increased, the mean glomeruli count in the samples did not change over the periods. CONCLUSIONS: In Turkey, IgAN is the most common primary glomerulonephritis, and the frequency of this is increasing.

Multidisciplinary approach to Fabry disease: from the eye of a neurologist.

Fabry Disease (FD) is an X-linked lysosomal storage disease that emerges as a result of the mutations in the galactosidase A gene encoding alpha-galactosidase. The peripheral nervous system (PNS) involvement manifests itself as acroparesthetic complaints due to the small-fiber involvement. Our goal was to assess the PNS involvement of 14 patients with FD both clinically and electrophysiologically besides the other systemic features. 14 patients (11 female and 3 male) of the same family whose enzyme level and genetic mutation analysis confirmed the FD diagnosis were evaluated retrospectively in terms of systemic and neurological findings of the FD. Neurological examination and nerve conduction studies were performed to evaluate the PNS involvement. PNS involvement was more common in females. Eight of the patients had acroparesthesia. The neurological examinations of all patients were normal. Two patients presented sensory axonal polyneuropathy, one of whom had no acroparesthesia. Other patients with acroparesthesia had normal nerve conduction studies. There was no significant relationship between the presence of acroparesthesia and the results of conduction studies (p > 0.05). Acroparesthetic complaints in patients with normal results were attributed to small-fiber involvement. Since small-diameter nerve fibers cannot be evaluated by routine conduction studies, especially in the early stages of FD, these studies may be normal. Early diagnosis through the symptoms such as acroparesthesia may contribute to the survival of the patient by preventing and/or delaying the development of renal, cardiac, and cerebrovascular diseases, which are the main causes of morbidity and mortality.

Peripheral arterial disease diagnosed by ankle-brachial index: Predictor for early renal replacement therapy in chronic kidney disease.

Our study aimed to investigate the relationship between ankle-brachial index (ABI) and need for early renal replacement therapy (RRT) in predialysis patients with chronic kidney disease (CKD). A total of 112 patients (62% men) with pre-dialysis CKD, seen in the outpatient clinic, were included, and ABI was obtained as per standard protocol. Peripheral arterial disease (PAD) was defined as ABI <0.9 or >1.3 in either leg. The clinical data were analyzed, and the risk factors for early RRT were determined by multivariate logistic regression analysis. The prevalence of PAD was 44% in predialysis CKD patients. Over three years' follow- up, 14.2% required RRT; 11.3% developed major cardiovascular event (myocardial infarction, stroke, or death). A total of 26 events occurred. The incidence of all events was significantly higher in patients with abnormal ABI than in those with normal ABI (34.7% vs. 12.7%; log rank P = 0.02). PAD was associated with all events [hazard ratio (HR): 2.72; 95% CI: 1.04-7.17; P = 0.042] as also the need for RRT (HR 3.2; 95% Cl: 1.005-10.23; P = 0.049), on univariate cox proportional hazard analysis. Multivariate logistic regression analysis adjusted for other risk factors identified that PAD remained an independent predictor for the need for early RRT (HR: 12.2; 95%Cl: 2.2-66.5; P = 0.004) and all events (HR: 3.5; 95% Cl: 0.9-13.5; P = 0.032). PAD was an independent predictor for RRT requirement in predialysis CKD.

Fabry Disease Prevalence in Renal Replacement Therapy in Turkey.

BACKGROUND: Fabry disease (FD) is an X-linked lysosomal storage disorder resulting from lack of alpha-galactosidase A (AGALA) activity in lysosomes. OBJECTIVE: In this multicenter study, we aimed to evaluate the prevalence of FD in renal transplant (Tx) recipients in Turkey. We also screened dialysis patients as a control group. METHODS: All Tx and dialysis patients were screened regardless of the presence of a primary disease. We measured the AGALA activity in all male patients as initial analysis. Mutation analysis was performed in male patients with decreased AGALA activity and in female patients as the initial diagnostic assay. RESULTS: We screened 5,657 patients. A total of 17 mutations were identified. No significant difference was observed between the groups regarding the prevalence of patients with mutation. We found FD even in patients with presumed primary kidney diseases. Seventy-one relatives were analyzed and mutation was detected in 43 of them. We detected a patient with a new, unknown mutation (p.Cys223) in the GLA gene. CONCLUSIONS: There are important implications of the screening. First, detection of the undiagnosed patients leads to starting appropriate therapies for these patients. Second, the transmission of the disease to future generations may be prevented by prenatal screening after appropriate genetic counseling. In conclusion, we suggest screening of kidney Tx candidates for FD, regardless of etiologies of chronic kidney disease.

A prospective study of living kidney donors: 6 years follow-up from a cardiovascular disease risk perspective

SUMMARY OBJECTIVE: The purpose of this prospective study was to evaluate the clinical, laboratory, and donation-specific outcomes of living kidney donors 6 years after donation. METHODS: We included a total of 93 kidney donors and 54 age- and sex-matched individuals as control group through a type 2 cohort consecutive recruitment. We detected kidney function abnormalities and the presence of hypertension, diabetes, and cardiovascular events during the 6 years follow-up period. RESULTS: The mean serum creatinine levels were higher (p<0.001), and the estimated glomerular filtration rate levels were lower (p<0.001) in living kidney donors 6 years after donation when compared with controls. The protein/creatinine ratio of the study population was also higher (p=0.014). There was no difference in outcomes between the groups for end-stage kidney disease and cardiovascular mortality. A higher rate of new-onset hypertension (6.4 vs. 32.9%), diabetes mellitus (0.0 vs. 4.3%), chronic kidney disease (0.0 vs. 2.1%), and cardiovascular disease (0.0 vs. 2.1%) was demonstrated among donors 6 years after donation (p<0.001, respectively). CONCLUSION: Our data have demonstrated that the reduction in Glomerular filtration rate induced by kidney donation might cause an increase in adverse renal and cardiovascular events.