Nephron Extra最新文献

Background: Genetically modified mice are used to investigate disease and assess potential interventions. However, research into kidney fibrosis is hampered by a lack of models of chronic kidney disease (CKD) in mice. Recently, aristolochic acid nephropathy (AAN), characterised by severe tubulointerstitial fibrosis, has been identified as a cause of end stage kidney disease and proposed as a model of CKD. Published studies have used various dosing regimens, species and strains, with variable outcomes. Therefore, we aimed to develop a standardised protocol to develop tubulointerstitial fibrosis using pure aristolochic acid I (AAI) in C57BL/6 mice.

Methods: AAI dose optimisation was performed by intraperitoneal injection of AAI at varying dose, frequency and duration. Kidney function was assessed by serum creatinine. Fibrosis was quantified by hydroxyproline levels and Masson's Trichrome staining. Specific collagens were measured by immunofluorescent staining.

Results: Single doses of AAI of >10 mg/kg caused acute kidney failure and death. Lower doses of 2.5 mg/kg needed to be administrated more than weekly to cause significant fibrosis. 3 mg/kg once every 3 days for 6 weeks followed by a disease development time of 6 weeks after AAI led to reduced kidney weight and function. Substantial tubulointerstitial fibrosis occurred, with males more severely affected. Increased deposition of collagen I, III and IV contributed to fibrosis, with collagen III and IV higher in males.

Conclusions: AAN can be induced in C57BL/6 mice. The regimen of 3 mg/kg every 3 days for 6 weeks followed by 6 weeks of disease development time gives substantial tubulointerstitial fibrosis with lesions similar to those in humans.

Aims: To assess the long-term therapeutic benefit of temporary depletion of B lymphocytes in patients with idiopathic membranous glomerulopathy (MGN) and search for potential predictors of response.

Patients and methods: The patients included had been diagnosed with biopsy-proven MGN in the absence of secondary causes. Estimated glomerular filtration rate should be above 30 ml/min/1.73 m(2) and 24-hour proteinuria 3 g/day or more. Patients who had been treated with cyclosporine or cytotoxic agents the year prior to study entry were excluded. Depletion of B cells was achieved with rituximab, which was administered intravenously for 4 consecutive weeks. Partial remission was defined as a >50% decrease in proteinuria with absolute proteinuria <3 g/day, while complete remission was defined as a >50% decrease in proteinuria and an absolute protein excretion <0.3 g/day.

Results: Twelve patients were studied (4 females/8 males) with a mean age of 51.3 years. No major adverse effects were observed. During a median follow-up time of 48 months, 11/12 (91.6%) patients achieved remission [7/12 (58.3%) complete remission and 4/12 (33.3%) partial remission], while 1 patient did not respond to therapy. Twelve months after therapy, 68.8% (p = 0.003) of cases had achieved partial and 28.4% complete remission. Measurements of lymphocyte subpopulations did not reveal any changes except for the B cell depletion. B cell infiltrates captured per mm(3) of renal tissue in the diagnostic biopsy did not correlate with subsequent response.

Conclusion: Depletion of B cells in idiopathic MGN was well tolerated and resulted in significant and long-lasting response rates in a series of 12 patients.

Diabetic nephropathy is a leading cause of end-stage renal disease worldwide. The mainstay of treatment has been glycemic control and blood pressure lowering using agents blocking the renin-angiotensin system. Clinical trials are currently under way using novel agents for the treatment of patients with diabetic nephropathy. Promising agents emerging from some of the completed trials include pirfenidone and bardoxolone methyl, which have been shown in two recent randomized controlled trials in patients with diabetic nephropathy to result in an improved estimated glomerular filtration rate compared to placebo. Also, paricalcitol has been shown to decrease the urinary albumin-to-creatinine ratio, whereas sulodexide failed to do so in a large randomized double-blind placebo-controlled trial. Of note, pyridoxamine has also shown promise in the treatment of diabetic nephropathy if started early in the disease course. These preliminary trials have shown significant promise for managing patients with diabetic nephropathy, sparking active research in this field and providing the rationale for further clinical testing in long-term, hard-outcomes trials.

Background/aims: Previous studies have shown the presence of high levels of glycoxidation and lipid peroxidation products in association with atherosclerosis in patients with end-stage kidney disease. Acetates are commonly used buffer for correcting metabolic acidosis in hemodialysis (HD) patients. Since the toxic effects of acetates are well established, acetate-free citrate dialysate (AFD) has become available in Japan. The objective of the present study was to evaluate the suppressive effects of AFD on oxidative stress in maintenance HD patients by measuring plasma pentosidine and malondialdehyde-modified low-density lipoprotein (MDA-LDL) levels as markers for glycoxidation and lipid peroxidation products.

Methods: Plasma pentosidine, MDA-LDL and other laboratory parameters were examined on maintenance HD at the Juntendo University Hospital before and after switching to AFD.

Results: MDA-LDL levels divided by LDL cholesterol were significantly lower than those before switching to AFD. Furthermore, levels of plasma pentosidine were lower than those before switching to AFD. Stepwise multiple regression analysis revealed that the percent change of the calcium-phosphorus product in the nondiabetic group and that of phosphorus in the diabetic group were predictive variables for the percent change of MDA-LDL/LDL, whereas the percent change of log high-sensitive C-reactive protein and that of systolic blood pressure in the nondiabetic group and that of diastolic blood pressure in the diabetic group were predictive variables for the percent change of plasma pentosidine.

Conclusions: It appears that AFD decreases glycoxidation and lipid peroxidation products when compared with acid citrate dextrose in HD patients. The reduction of oxidative stress by AFD during HD may have possible beneficial effects on atherosclerosis through calcium-phosphorus metabolism and blood pressure.

Backgrounds: Criteria that may guide early renal replacement therapy (RRT) initiation in patients with acute kidney injury (AKI) currently do not exist.

Methods: In 120 consecutive patients with AKI, clinical and laboratory data were analyzed on admittance. The prognostic power of those parameters which were significantly different between the two groups was analyzed by receiver operator characteristic curves and by leave-1-out cross validation.

Results: Six parameters (urine albumin, plasma creatinine, blood urea nitrogen, daily urine output, fluid balance and plasma sodium) were combined in a logistic regression model that estimates the probability that a particular patient will need RRT. Additionally, a second model without daily urine output was established. Both models yielded a higher accuracy (89 and 88% correct classification rate, respectively) than the best single parameter, cystatin C (correct classification rate 74%).

Conclusions: The combined models may help to better predict the necessity of RRT using clinical and routine laboratory data in patients with AKI.

Background: Patients with type 2 diabetes mellitus and advanced kidney disease are usually treated with insulin. However, the prolonged pharmacokinetic insulin profile in patients with delayed renal insulin elimination impairs a successful therapy. Due to its hepatic metabolism, pioglitazone is a potential candidate for additional administration. The aim of this study was to investigate the effect of pioglitazone versus placebo on total daily insulin requirements and several pleiotropic factors in type 2 diabetes patients requiring hemodialysis.

Methods: The effect of pioglitazone (30 mg) versus placebo was explored in this prospective, randomized, double-blind parallel multicenter phase II study analyzing data from 36 patients with type 2 diabetes mellitus currently under hemodialysis (25 male, 11 female, aged 69.2 ± 7.9 years, baseline HbA1c 7.6 ± 0.9%). The most important efficacy parameters collected before dialysis and after an overnight fast at baseline and after 6 months were: total daily insulin dose, HbA1c, fasting blood glucose, adiponectin, HDL, LDL, triglycerides, NT-proBNP, and ultrafiltrate volume.

Results: Application of pioglitazone resulted in a significant decrease of the daily insulin dose by 35% versus baseline (placebo: -10%, n.s.), improvement in HbA1c (-0.60 ± 0.87%, p = 0.015; placebo: 0.21 ± 1.1%, n.s.) and adiponectin (7.33 ± 4.80 mg/l, p < 0.001; placebo: -1.37 ± 2.56 mg/l, n.s.). Slight improvements or no changes were seen with fasting glucose, triglycerides, HDL, LDL and NT-proBNP. There was no indication of increased hypoglycemia risk and volume overload by the addition of pioglitazone.

Conclusions: Addition of pioglitazone to insulin in patients with late-stage kidney failure requiring hemodialysis is a well-tolerated treatment option that improves glycemic control with simultaneous insulin-sparing potential.

Unlabelled: BACKGROUND/AIMSBACKGROUND/AIMS: While experimental models that emulate diabetic nephropathy are valuable tools for elucidating pathogenetic mechanisms and developing novel therapies, existing models imperfectly recapitulate human disease. In diabetes, hyperglycemia and hemodynamic forces act in concert to induce renal injury. Accordingly, in the present study, we combined streptozotocin-induced diabetes with surgical ablation of 5/6 of the kidney mass with the aim of evaluating their additive effects on renal function and glomerular morphology.

Methods: Female F344 rats were randomized to undergo subtotal nephrectomy (SNx) either at baseline or following 4 weeks of diabetes.

Results: In comparison to sham rats, rats with diabetes or rats after SNx surgery, diabetic subtotally nephrectomized (DM-SNx) rats demonstrated an increase in systolic blood pressure, glomerular volume and mesangial matrix. Albuminuria was synergistically increased by hyperglycemia and renal mass ablation associated with decreased nephrin expression. In contrast, glomerular capillary rarefaction and glomerular filtration rate were similarly reduced in SNx and DM-SNx rats.

Conclusion: The DM-SNx rat recapitulates some of the features of human disease, most notably augmented albuminuria. Since this model avoids the deletion or overexpression of gene(s) linked to the pathogenesis of nephropathy, the DM-SNx rat model represents a complementary tool for the trial of novel therapies.

Background/aims: Although contrast-induced acute kidney injury (CIAKI) is a major complication associated with angiography, the prophylaxis is not well established. Use of a low dose of carperitide for preventing CIAKI remains controversial. We examined the protective effect of carperitide on CIAKI after coronary angiography with a small contrast volume in chronic kidney disease (CKD) patients with coronary artery disease.

Methods: We randomly assigned 112 consecutive patients to a carperitide or a control group. The contrast volume was kept under 150 ml. The primary endpoint was the incidence of CIAKI defined by a serum creatinine of ≥25% or a serum creatinine of ≥0.5 mg/dl from baseline within 48 h. The secondary endpoint was a change in renal function at 1 week after the procedure.

Results: The baseline characteristics and contrast volumes (carperitide group: 67.4 ± 38.2 ml vs. control group: 64.8 ± 20.5 ml, p = 0.661) were comparable in the two groups. The incidence of CIAKI was similar in the two groups (carperitide group: 8.5% vs. control group: 5.7%, p = 0.564). A multivariate analysis revealed that a hypotension ≥20 mm Hg was a significant predictor of developing CIAKI in the carperitide group (p = 0.015). The incidence of CIAKI in the carperitide group without hypotension was rare, but not significantly different (carperitide group: 2.4% vs. control group: 5.7%, p = 0.432).

Conclusions: This study indicated that the use of a small contrast volume suppressed the incidence of CIAKI and that carperitide had no prophylactic effect against CIAKI. Our results also revealed the impact of hypotension on the development of CIAKI in the carperitide group.