Different risk factors are associated with vascular access patency after construction and percutaneous transluminal angioplasty in patients starting hemodialysis.

BACKGROUND: The objective of this multicenter, prospective observational study was to determine the factors related to patency rates after construction of vascular access (VA) and the first percutaneous transluminal angioplasty (PTA). METHODS: The 24-month primary and secondary patency rates after construction of a radiocephalic arteriovenous fistula (RC-AVF) and arteriovenous graft (AVG) were evaluated using the Kaplan-Meier method and log-rank test. The 12-month post-PTA patency rate was also investigated. A Cox proportional hazard model was used to identify clinical parameters associated with the primary patency rate and the post-PTA patency rate. RESULTS: A total of 611 patients were enrolled in the study. The primary patency rate after VA construction was lower in hemodialysis (HD) patients with an AVG than in those with an AVF. Aging (hazard ratio [HR], 1.02 per 1 year; p < 0.001), female sex (HR, 1.41; p = 0.03), diabetes mellitus (HR, 1.37; p = 0.03), low serum albumin (HR, 0.76 per 1-g/dL decrease; p = 0.02), and use of an erythropoietin-stimulating agent (HR, 1.62; p = 0.02) were risk factors for VA problems. The post-PTA patency rate was associated with aging (HR, 1.02; p < 0.001), diabetes mellitus (HR, 1.49; p = 0.02), polycystic kidney disease (HR, 2.14; p = 0.01), temporary catheter use for initiation of HD (HR, 1.60; p = 0.02), and period from VA construction to use (HR, 0.99; p = 0.04). CONCLUSION: Although a poor patency rate is commonly associated with advanced age and diabetes, different risk factors affect patency between VA construction and the first PTA.

Comparing the 12-month patency of low- versus high-pressure dilation in failing arteriovenous fistulae: A prospective multicenter trial (YOROI study).

PURPOSE: This study was performed to investigate the effect of the balloon dilation pressure on the 12-month patency rate in patients with failed arteriovenous fistulas undergoing hemodialysis. MATERIALS AND METHODS: In this multicenter, prospective, randomized trial, the 4-mm-diameter YOROI balloon was used for dilation of stenotic lesions. The balloons were inflated to a pressure of 8 atm (low-pressure group) or 30 atm to achieve complete expansion (high-pressure group). The 12-month patency rate after balloon angioplasty was analyzed by the Kaplan-Meier method and log-rank test and/or a Cox proportional hazard model. We also investigated the dilation pressure required to achieve complete expansion in the high-pressure group. RESULTS: In total, 71 patients were enrolled and allocated to either the low-pressure group (n = 34) or the high-pressure group (n = 37). The 12-month patency rates showed no significant difference between the low- and high-pressure groups (47% and 49%, respectively; p = 0.87). In the low-pressure group, the patency rate was not different between patients with complete dilation and residual stenosis (44% and 50%, respectively; p = 0.87). The Cox proportional hazard model revealed that the 12-month patency rate was associated with the stenosis diameter (hazard ratio 0.36; p = 0.001) and the presence of diabetes (hazard ratio 0.33; p = 0.018). Finally, the pressure required to achieve complete dilation was ≤20 atm in 76% of patients and ≤30 atm in 97% of patients. One patient required a dilation pressure of >30 atm. CONCLUSION: The patency rate does not differ between low-pressure dilation and high-pressure dilation.

Efficacy of add-on therapy of aliskiren to an angiotensin II receptor blocker on renal outcomes in advanced-stage chronic kidney disease: a prospective, randomized, open-label study.

BACKGROUND: Combination therapy of aliskiren and an angiotensin II receptor blocker (ARB) has been reported to be effective for reducing the level of proteinuria. However, it remains unclear whether this combination therapy contributes to suppression of kidney disease progression. The aim of this study was to investigate the effect of aliskiren on hard renal endpoints, when added to an ARB, in patients with advanced chronic kidney disease (CKD). METHODS: The study design was a prospective, randomized open-label design. 83 CKD patients (52 men and 31 women) were enrolled and assigned randomly to an aliskiren add-on group (n = 42) or control group (n = 41). Entry criteria included elevated serum creatinine ≥ 1.5 mg/dl, urine protein excretion (≥ 1+ on urine dipstick test), and hypertension. All participants were treated with an ARB. The follow-up period was 12 months. 12 participants were withdrawn during the study period and the study was terminated in January 2012 as a consequence of the results of the interim analysis of the ALTITUDE study. RESULTS: Nine patients in the aliskiren group and seven patients in the control group started dialysis. Doubling of the serum creatinine level occurred in one patient in the control group. A Cox proportional hazards test showed that dual blockade of the renin-angiotensin-aldosterone system with aliskiren and ARB was not associated with improvement in hard renal endpoints. CONCLUSION: We conclude that aliskiren add-on therapy to an ARB may not give any benefit and, therefore, should not be recommended in CKD patients.

An oral adsorbent, AST-120, combined with a low-protein diet and RAS blocker, for chronic kidney disease.

BACKGROUND: A low-protein diet and treatment with renin-angiotensin system (RAS) blockers can delay the progression of chronic kidney disease (CKD). The oral adsorbent AST-120 (Kremezin) has a renoprotective effect by reducing serum levels of uremic toxins. We investigated the influence of AST-120 on the preservation of renal function in patients with CKD. METHODS: Twenty-eight patients were randomized to 2 groups: 15 patients receiving 6.0 g of AST-120 daily for 12 months plus a low-protein diet and RAS blocker therapy (group A) and 13 patients who were not given AST-120 (group B). All of them had shown progressive deterioration of renal function with basal treatment. Mean baseline serum creatinine level (+/- standard deviation) was 2.4 +/- 0.8 mg/dL in group A and 2.7 +/- 0.8 mg/dL in group B. There were no significant differences in background parameters before AST-120 therapy. RESULTS: The change in the estimated glomerular filtration rate (eGFR) was significantly smaller in group A than in group B. The change was also significantly smaller in patients with a baseline serum creatinine <2.4 mg/dL and in patients with rapid progression. After 12 months, the slope of the eGFR curve was significantly less steep compared with baseline in group A (-1.77 vs. -0.52 ml/min per month), but there was no significant change in group B. The slope was also significantly less steep in patients with rapid progression. CONCLUSIONS: Adding AST-120 to a low-protein diet and RAS blocker therapy may delay the deterioration of chronic renal failure, especially in patients with early or rapid progression.

Tgf-beta1 induced by high glucose is controlled by angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker on cultured human peritoneal mesothelial cells.

BACKGROUND: Loss of peritoneal function is a major complication associated with long-term peritoneal dialysis. Observed changes include loss and degeneration of the mesothelium, submesothelial thickening, alterations in the structure and number of blood vessels, and reduplication of the vascular basement membrane. Exposure to high glucose concentrations in peritoneal dialysis solutions is known to cause injury to cultured human peritoneal mesothelial cells (HPMC) as a result of overexpression of transforming growth factor beta 1 (TGF-beta1). Previous studies have demonstrated that angiotensin II (AII) increases expression of TGF-beta1 in a number of different cell types; although this has not been demonstrated in HPMC. OBJECTIVE: To clarify possible mechanisms involved in peritoneal fibrosis, we investigated whether HPMC expressed AII-forming pathway mRNA and whether increases in AII induced by high glucose contribute to the production of TGF-beta1. We also examined the effects of the angiotensin-converting enzyme inhibitor (ACEI) perindoprilat and the AII receptor blocker (ARB) candesartan on expression of TGF-beta1 and proliferation of HPMC. METHODS: Expression of mRNA for the AII-forming pathway and TGF-beta1 in HPMC was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitative RT-PCR. Levels of AII and TGF-beta1 following 48 hours of incubation of the cells in a range of glucose concentrations were measured by enzyme immunoassay and enzyme linked immunosorbent assay respectively. The effect of glucose on cell proliferation was examined using the water-soluble tetrazolium salt WST-1 and [3H]-thymidine uptake. We also investigated the effect of ACEI and ARB on the expression of TGF-beta1 and the proliferation of HPMC incubated at high glucose for 48 hours. RESULTS: AII-forming pathway mRNA was detected in HPMC, with expression of angiotensinogen, angiotensin-converting enzyme (ACE), AII type 1 receptor, and TGF-beta1 mRNA increasing following exposure to glucose according to glucose concentration. High glucose was also shown to increase the production of All and TGF-beta1 and decrease the proliferation of HPMC. In contrast, we found that both the ACEI and the ARB attenuated the increase in TGF-beta1 production and reduced cell proliferation caused by exposure to high glucose. These effects were greater with a combination of the two drugs. CONCLUSION: The present study provides evidence that (1) HPMC express mRNA for the AII-forming pathway; (2) ACEI and ARB inhibit the TGF-beta1 production induced by high glucose; (3) the AII-forming pathwayis one mechanism by which high glucose causes production of TGF-beta1. In addition to having antihypertensive and renal-protective effects, combination therapy with an ACEI and an ARB may also be effective in preventing loss of peritoneal function and decreasing peritoneal fibrosis.

Effect of glucose polymer on the intercellular junctions of cultured human peritoneal mesothelial cells.

BACKGROUND: Glucose polymer is an active osmotic agent that is increasingly used as an alternative to glucose in peritoneal dialysis fluids. It was recently reported that the duration of peritoneal dialysis can be extended by using glucose polymer in patients with poor ultrafiltration. We previously demonstrated that high glucose levels damage the intercellular junctions of cultured human peritoneal mesothelial cells (HPMC), but little is known about the influence of glucose polymer. Therefore, we investigated the effects of glucose polymer on the intercellular junctions of HPMC. METHODS: HPMC were isolated, cultured, and identified according to the modified method of Stylianou. M199 medium was supplemented with peritoneal dialysis solutions containing 7.5% glucose polymer or 1.5, 2.5, and 4.25% glucose. After 6 h, cell viability was assessed, intercellular junction proteins were examined by immunofluorescence techniques, and the concentration of transforming growth factor-beta1 in the culture supernatant was determined. RESULTS: Glucose significantly suppressed cell viability and significantly increased transforming growth factor-beta1 production when compared with control or glucose polymer cultures. Peritoneal dialysis solutions containing 4.25% glucose caused the detachment of HPMC. Immunofluorescence of intercellular junction proteins (tight junctions: ZO-1, occludin, and claudin-1; adherens junctions: beta-catenin) became weak and uneven after culture with glucose. On the other hand, glucose polymer caused little change in the immunofluorescence of these proteins when compared with control cultures. CONCLUSIONS: Glucose polymer seems to be less toxic to HPMC than glucose itself, suggesting that the glucose polymer may be better for peritoneal dialysis.

T(-786)-->C polymorphism of the endothelial nitric oxide synthase gene influences the progression of renal disease.

BACKGROUND/AIMS: Polymorphism of the endothelial nitric oxide synthase (ecNOS) gene may be involved in renal disease. Recently, T(-786)-->C polymorphism affecting ecNOS gene transcription has been reported. To clarify the role of T(-786)-->C polymorphism in renal disease, we investigated hemodialysis patients and healthy controls for this polymorphism and we compared its frequency with that of intron 4 polymorphism in the hemodialysis patients. METHODS: The subjects were 252 patients who had been on hemodialysis for less than 2 years (168 with nondiabetic nephropathy and 84 with diabetic nephropathy) and 187 healthy controls. T(-786)-->C polymorphism was detected using polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: The frequencies of the T/C and C/C genotypes were significantly higher in the nondiabetic hemodialysis patients than in the controls (odds ratio 1.41; 95% Cl 1.03-2.00), and were also significantly higher in the diabetic hemodialysis patients than in the controls (odds ratio 1.56; 95% Cl 1.02-2.41). In addition, T(-786)-->C polymorphism and intron 4 polymorphism showed strong linkage disequilibrium. CONCLUSION: T(-786)-->C polymorphism may be involved in the progression of both nondiabetic and diabetic nephropathy, along with intron 4 polymorphism.