A UFLC-MS/MS Method for the Simultaneous Analysis of Urinary Podocin and Podocalyxin in Patients with Nephrotic Syndrome.

OBJECTIVE: To create an efficient and robust mass spectrometric method for the simultaneous quantitation of podocin and podocalyxin in urine samples and to evaluate urinary podocin and podocalyxin levels in patients with nephrotic syndrome (NS). METHODS: A mass spectrometric method was generated for the measurement of tryptic peptides in urine sediment. Separation of peptides was achieved via liquid chromatography, and mass spectrometric analyses were conducted by electrospray ionization triple-quadrupole mass spectrometry in the multiple reaction monitoring mode. RESULTS: Intra- and interassay precision values were below 12% and accuracies ranged from 87% to 111% for both of peptides. The validated method was successfully applied to detect these peptides in patients with NS. Urine podocin and podocalyxin levels were significantly higher in patients with NS compared to healthy controls. CONCLUSIONS: This proposed mass spectrometric method provides technological evidence that will benefit the clinical field in the early diagnosis and follow-up of NS.

Serum uromodulin levels, MR imaging findings, and their relationship with eGFR-based CKD staging in ADPKD patients.

PURPOSE: Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease that may progress to end-stage renal disease, characterized by increased kidney volume due to cystic formations. In this study, we aimed to investigate the relationship between serum uromodulin levels, total kidney volume and estimated glomerular filtration rate (eGFR) in patients with ADPKD. METHODS: This study included a total of 54 ADPKD patients and 18 healthy volunteers (control group). Total kidney volumes were calculated through magnetic resonance images using ellipsoid method. Serum uromodulin measurements were measured using an ELISA method. RESULTS: Serum uromodulin levels were lower in patients compared with the control group (2.47 ± 0.16 vs 2.6 ± 0.28, p = 0.021). There was no significant difference in uromodulin values among the patients in chronic kidney disease (CKD) stages 1-2, 3 and 4-5. TKV measurements of CKD stage 4-5 patients were significantly higher than the stage 1-2 patients (p = 0.015). A negative correlation was observed between TKV and eGFR (r = - 0.433, p = 0.001). A positive correlation was observed between uromodulin and eGFR (r = 0.274, p = 0.02). When the serum levels of uromodulin and the level of eGFR were evaluated using simple linear regression analysis, R2 value was found to be 0.075, suggesting that 7.5% change in serum uromodulin values corresponds with the change in eGFR value. CONCLUSION: These findings are consistent with previous studies that reported that serum uromodulin may be a good biomarker for demonstrating renal function in the early stages of CKD, before eGFR levels deteriorate. Serum uromodulin level may be useful in demonstrating renal functions in the follow-up of individuals with ADPKD.

A case of cyclic hemoperitoneum in a hemodialysis patient: Encapsulated peritoneal sclerosis complicated by endometriosis and fungal peritonitis.

Encapsulated peritoneal sclerosis (EPS) is a rare, but frequently fatal, long-term complication of peritoneal dialysis. Endometriosis is a common gynecological problem but hemoperitoneum due to endometriosis has been reported to be extremely rare in hemodialysis (HD) patients. A 25-year-old female HD patient was admitted to our clinic with nausea, vomiting, abdominal pain, and weight loss for last 3 months. Candida tropicalis and Candida glabrata were isolated in the fungal cultures from peritoneal fluid. Her abdominal computerized tomography scan has shown irregular peritoneal calcifications, diffuse peritoneal thickening, dilatation of the small bowel loops, and cocoon formation which all were typical for EPS. Hemoperitoneum was reported to recur for four times with intervals suggesting menstrual cycles. Her peritoneal biopsy, along with the signs of EPS, has also revealed the presence of endometriosis. The patient died with symptoms of septic shock in the first year of EPS diagnosis.

Hemophagocytic syndrome in kidney transplant recipients: report of four cases from a single center.

BACKGROUND: The prognosis of hemophagocytic syndrome (HPS) in kidney transplant recipients is reported to be poor, however the optimal therapeutic approach is still unclear. PATIENTS AND METHODS: The clinical and follow-up data of the 4 patients with HPS (3 male, 1 female; age 39.7 +/- 11.3 years) among 368 kidney transplant recipients during a 5-year period were retrospectively analyzed. RESULTS: HPS developed 35-61 days in the post-transplant period. All 4 patients presented with fever. Hepatosplenomegaly and lymphadenopathy were observed only in the first patient. Laboratory tests revealed pancytopenia and hyperferritinemia in all patients, but elevated liver enzymes were observed in 3. Two patients had cytomegalovirus infection, and 1 had Epstein-Barr virus infection. Three patients died despite aggressive supportive therapy, however the fourth case survived after graft nephrectomy. CONCLUSION: HPS pathogenesis in kidney transplants appears to be related with the graft itself. Graft nephrectomy may be the preferable therapeutic approach for kidney transplant recipients with HPS resistant to standard supportive therapy.

Serum levels of prostate-specific antigen and vitamin D in peritoneal dialysis patients.

Measuring the free:total ratio of prostate-specific antigen (f/t-PSA) can improve the specificity of single-serum PSA values, distinguishing between benign prostatic hyperplasia (BPH) and prostatic carcinoma (PCa) in men over the age of 50. Additionally, clinical trials have shown that dihydroxyvitamin D3 can slow the rate of PSA rise in PCa patients. However, little is known regarding the applicability of those findings in men undergoing chronic peritoneal dialysis (CPD). In the present study, we investigated the prevalence of increased serum PSA levels among CPD patients and correlated those values with serum levels of vitamin D [25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3]. We undertook a cross-sectional study of 71 male CPD patients without a known history of prostate cancer from 24 centers in Canada, Greece, and Turkey. All of the patients were more than 50 years of age. In these patients, we measured serum concentrations of PSA, free PSA (f-PSA), total PSA (t-PSA), prostate alkaline phosphatase (PAP), 25-hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, and intact parathyroid hormone (iPTH). We recorded serum PSA levels < 4 ng/mL in 62 patients (87.3%, group A) and levels > 4 ng/mL in 9 patients (12.7%, group B). The f/t-PSA ratio was < 0.25 in 16 patients (22.5%). Group B patients were older than those in group A (median: 73 years vs. 65 years, p < 0.01) and had a lower body weight (median: 66.5 kg vs. 76.7 kg, p < 0.05). We observed no statistically significant difference between the two groups for serum 1,25-dihydroxyvitamin D3 (median: 9.8 ng/mL vs. 10.1 ng/mL) or 25-hydroxyvitamin D3 (8 ng/mL vs. 8.2 ng/mL) levels. Also, we observed no correlation between vitamin D levels and f/t-PSA, but iPTH levels were significantly higher in group A (200.5 pg/mL vs. 61.2 pg/mL, p < 0.04). Also, serum PAP levels correlated significantly with PSA (r = 0.49, p = 0.01) and with f-PSA (r = 0.56, p = 0.000). Our results showed no clear relationship between vitamin D and serum levels of PSA or-of f/t-PSA in PD patients. However, further studies are needed to better define the uses of these PSA markers in PD patients because, in such patients, other relevant factors might be implicated in their predictive value.

The potential role of advanced glycation end product and iNOS in chronic renal failure-related testicular dysfunction. An experimental study.

OBJECTIVES: To investigate the impact of advanced glycation end products (AGEs) and inducible nitric oxide synthase (iNOS) in chronic renal failure (CRF)-associated testicular dysfunction in an experimental model. In additionally, we examined whether different peritoneal dialysis (PD) fluids could contribute to the elevation in AGE level and iNOS expression in the testes. METHODS: Adult male Wistar rats, 10 and 12 weeks of age and weighing 200-330 g, were divided into 5 groups. Group 1 served as the control group. In group 2, CRF was induced and a peritoneal catheter was implanted, but the dialysis procedure was not performed until the end of the study. In group 3, CRF was induced and PD was performed with dialysis fluids containing 1.36% glucose and icodextrin. In group 4, CRF rats received dialysis fluids containing 3.86% glucose and icodextrin. Finally, an indwelling catheter was implanted and the dialysis procedure was performed using dialysis fluids containing 3.86% glucose and icodextrin (group 5). Chronic PD began 4 weeks after insertion of the catheter. Each morning, this fluid was drained and 20 ml dialysis fluid, containing either 1.36 or 3.86% glucose, was given intraperitoneally for 4 h in unanesthetized animals. Each evening, 20 ml icodextrin was given for 10 h. The dialysis procedure was performed for 8 weeks. The AGE level was determined from the 5-hydroxymethyl-2-furaldehyde (5-HMF) content of penis samples and iNOS expression was assessed by immunohistochemistry. RESULTS: The elevation of 5-HMF was significant in the testes from groups 2, 3, 4, and 5 when compared with group 1. Furthermore, the differences between groups 2 and 4, 3 and 4, and 4 and 5 were also significant (p < 0.05). Immunohistochemical analysis revealed the presence of iNOS predominantly in the Leydig cells. While iNOS staining was significantly lower in group 1 than in other groups, there were also significant differences between groups 2 and 3, 2 and 4, 2 and 5, 3 and 5, and 4 and 5 (p < 0.05). Finally, a significant statistical correlation was found between the 5-HMF and iNOS levels (r = 0.698, p = 0.001). CONCLUSIONS: The present study identifies, for the first time, a potential role of AGE and iNOS in experimental CRF-associated testicular dysfunction. In addition, we found that PD fluids containing glucose contribute to this effect. These results may lead to a better understanding of the pathophysiological pathway in CRF-related testicular dysfunction.