C allele in transforming growth factor-ß1 rs1800471 gene polymorphisms might indicate a protective feature in encapsulating peritoneal sclerosis development.

INTRODUCTION: Peritoneal fibrosis may progress in peritoneal dialysis (PD) patients to a fatal clinical condition called encapsulating peritoneal sclerosis (EPS). Transforming growth factor (TGF)-ß plays a pivotal role in the pathogenesis of peritoneal fibrosis. We aimed to investigate the association among polymorphisms in the gene encoding TGF-ß1, which were -509C/T (rs1800469), +869T/C (rs1982073), and +915G/C (rs1800471) in EPS patients. METHODS: A total of 16 PD patients who were clinically and radiologically diagnosed with EPS were enrolled and 22 age- and gender-matched PD patients were selected as the non-EPS group. RESULTS: G allele frequency at the rs1800471 gene polymorphism was significantly higher in the EPS group than non-EPS group (p = 0.005). Interestingly, the non-EPS group patients had CC or CG polymorphisms. CONCLUSION: C allele in TGF-ß1 rs1800471 gene polymorphisms might indicate a protective feature in EPS development. Knowing the presence of polymorphism may be effective in selecting renal replacement therapy in patients.

High serum soluble α-Klotho levels in patients with autosomal dominant polycystic kidney disease.

This study aims to determine fibroblast growth factor-23 and soluble α-Klotho levels in patients with autosomal dominant polycystic kidney disease. A total of 76 patients with autosomal dominant polycystic kidney disease and 32 healthy volunteers were included in the study. Serum fibroblast growth factor-23 and soluble α-Klotho levels were measured with ELISA kits. Parathyroid hormone, phosphate, calcium, creatinine, 25-hydroxyvitamin D3 levels, urinary protein to creatinine ratio and estimated glomerular filtration rate were also measured or calculated. Patients with autosomal dominant polycystic kidney disease had significantly higher serum parathyroid hormone (p<0.001), fibroblast growth factor-23 (p<0.001), soluble α-Klotho levels (p=0.001) and lower serum 25-hydroxyvitamin D3 levels (p<0.001) as compared with healthy volunteers. Serum fibroblast growth factor-23, soluble α-Klotho and 25-hydroxyvitamin D3 levels were similar in all five chronic kidney disease stages of autosomal dominant polycystic kidney disease (p>0.05). Fibroblast growth factor-23 (r=-0.251, p=0.034) and soluble α-Klotho levels (r=-0.251, p=0.034) were found to be negatively correlated with estimated glomerular filtration rate. This study shows increased fibroblast growth factor-23 levels in patients with autosomal dominant polycystic kidney disease which is in harmony with the general trend in patients with chronic kidney disease of other aetiologies, but, unlike them, also a significant increase in serum soluble α-Klotho levels in patients with autosomal dominant polycystic kidney disease suggesting an aberrant production or a decreased clearance of α-Klotho molecule. Considering the unique increases in erythropoietin levels due to erythropoietin production in renal cysts, we assume, patients with autosomal dominant polycystic kidney disease may potentially have different soluble α-Klotho production/clearance characteristics than the patients with other parenchymal renal diseases.

Bone mineral density and its correlation with clinical and laboratory factors in chronic peritoneal dialysis patients.

The aim of this study was to assess the clinical and laboratory correlations of bone mineral density (BMD) measurements among a large population of patients on chronic peritoneal dialysis (PD). This cross-sectional, multicenter study was carried out in 292 PD patients with a mean age of 56 +/- 16 years and mean duration of PD 3.1 +/- 2.1 years. Altogether, 129 female and 163 male patients from 24 centers in Canada, Greece, and Turkey were included in the study. BMD findings, obtained by dual-energy X-ray absorptiometry (DEXA) and some other major clinical and laboratory indices of bone mineral deposition as well as uremic osteodystrophy were investigated. In the 292 patients included in the study, the mean lumbar spine T-score was -1.04 +/- 1.68, the lumbar spine Z-score was -0.31 +/- 1.68, the femoral neck T-score was -1.38 +/- 1.39, and the femoral neck Z score was -0.66 +/- 1.23. According to the WHO criteria based on lumbar spine T-scores, 19.2% of 292 patients were osteoporotic, 36.3% had osteopenia, and 44.4% had lumbar spine T-scores within the normal range. In the femoral neck area, the prevalence of osteoporosis was slightly higher (26%). The prevalence of osteoporosis was 23.3% in female patients and 16.6% in male patients with no statistically significant difference between the sexes. Agreements of lumbar spine and femoral neck T-scores for the diagnosis of osteoporosis were 66.7% and 27.3% and 83.3% for osteopenia and normal BMD values, respectively. Among the clinical and laboratory parameters we investigated in this study, the body mass index (BMI) (P < 0.001), daily urine output, and urea clearance time x dialysis time/volume (Kt/V) (P < 0.05) were statistically significantly positive and Ca x PO(4) had a negative correlation (P < 0.05) with the lumbar spine T scores. Femoral neck T scores were also positively correlated with BMI, daily urine output, and KT/V; and they were negatively correlated with age. Intact parathyroid hormone levels did not correlate with any of the BMD parameters. Femoral neck Z scores were correlated with BMI (P < 0.001), and ionized calcium (P < 0.05) positively and negatively with age, total alkaline phosphatase (P < 0.05), and Ca x P (P < 0.01). The overall prevalence of fractures since the initiation of PD was 10%. Our results indicated that, considering their DEXA-based BMD values, 55% of chronic PD patients have subnormal bone mass-19% within the osteoporotic range and 36% within the osteopenic range. Our findings also indicate that low body weight is the most important risk factor for osteoporosis in chronic PD patients. An insufficient dialysis dose (expressed as KT/V) and older age may also be important risk factors for osteoporosis of PD patients.