Upstream Regulators and Downstream Effectors of NADPH Oxidases as Novel Therapeutic Targets for Diabetic Kidney Disease

Oxidative stress has been linked to the pathogenesis of diabetic nephropathy, the complication of diabetes in the kidney. NADPH oxidases of the Nox family, and in particular the homologue Nox4, are a major source of reactive oxygen species in the diabetic kidney and are critical mediators of redox signaling in glomerular and tubulointerstitial cells exposed to the diabetic milieu. Here, we present an overview of the current knowledge related to the understanding of the role of Nox enzymes in the processes that control mesangial cell, podocyte and tubulointerstitial cell injury induced by hyperglycemia and other predominant factors enhanced in the diabetic milieu, including the renin-angiotensin system and transforming growth factor-β. The nature of the upstream modulators of Nox enzymes as well as the downstream targets of the Nox NADPH oxidases implicated in the propagation of the redox processes that alter renal biology in diabetes will be highlighted.     

Adenosine mediates transforming growth factor-beta 1 release in kidney glomeruli of diabetic rats

Up regulation of the transforming growth factor-beta 1 (TGF-β1) axis has been recognized as a pathogenic event for progression of glomerulosclerosis in diabetic nephropathy. We demonstrate that glomeruli isolated from diabetic rats accumulate up to sixfold more extracellular adenosine than normal rats. Both decreased nucleoside uptake activity by the equilibrative nucleoside transporter 1 and increased AMP hydrolysis contribute to raise extracellular adenosine. Ex vivo assays indicate that activation of the low affinity adenosine A_2B receptor subtype (A_2BAR) mediates TGF-β1 release from glomeruli of diabetic rats, a pathogenic event that could support progression of glomerulopathy when the bioavailability of adenosine is increased.     

Nephrotoxicity of Penicillium aurantiogriseum and P. commune from an endemic nephropathy area of Yugoslavia

Seven out of nine Penicillium isolates from mouldy maize in Yugoslavia have been differentiated into the adjacent species P. aurantiogriseum and P. commune. Nephrotoxicity of cultured mycelia in the rat has been demonstrated for all isolates of both species and was correlated usefully, though indirectly, with the production of benzodiazepine secondary metabolites, notably auranthine. Shredded wheat (22 g) moulded by an example of each species and fed to a rat over 4 days elicited renal pathology in the P₃ segment of proximal tubules, involving frequent pyknosis and extensive mitosis typical of this as yet uncharacterised toxin. The effect was attributed in P. aurantiogriseum at least partly to the spores. Prominent pathology was elicited by only lg of spores given over 4 days.     

Effects of glycated albumin on mesangial cells: evidence for a role in diabetic nephropathy

Nonenzymatically glycated proteins are preferentially transported across the glomerular filtration barrier, and the glomerular mesangium in diabetes is bathed with serum containing increased concentrations of glycated albumin. We investigated effects of glycated albumin on mesangial cells, which are involved in diabetic nephropathy. [³H]-thymidine incorporation was significantly inhibited when murine mesangial cells were grown in culture media containing human serum that had been nonenzymatically glycated by incubation for 4 days with 28 mM glucose. This inhibition was reversed when monoclonal antibodies that selectively react with Amadori products of glycated albumin were added to the culture media. Purified glycated albumin containing Amadori adducts of the glycation reaction induced significant inhibition of thymidine incorporation and stimulation of Type IV collagen secretion compared with cells cultured in the presence of purified nonglycated albumin. These changes were prevented when monoclonal antibodies specifically reactive with fructosyl-lysine epitopes in glycated albumin were added to the cultures. The antibodies had no effect on growth or collagen production in the presence of nonglycated albumin. The results provide the first evidence directly implicating Amadori adducts in glycated albumin in the pathogenesis of diabetic nephropathy, which is characterized by decreased cellularity in association with expansion of the mesangial matrix.     

Effect of triethylenepentaminehexaacetic acid on the renal damage in cadmium-treated Syrian hamsters

Cadmium (Cd)-induced nephropathy was treated by triethylene-pentaminehexaacetic acid (TTHA) in male Syrian hamsters. Hamsters injected three times a week with 3 mg/kg body wt CdCl₂ showed proteinuria, urinaryN-acetyl-β-d-inglucosaminidase (NAG), and fractional excretion of sodium (FENa) when compared to saline-injected control. Cd-treated hamsters injected ip with TTHA 10 mg/kg body wt five times a week showed reduction of renal damage, including reductions in urinary protein (from 6.7±2.2 to 4.3±0.5 mg/d) and NAG (0.17±0.06 to 0.04±0.02 U/d). Urinary excretion of Cd was significantly increased (from 87±51.3 to 3052±1485 mg/L) by TTHA administration. Cd concentration in renal cortical tissue was slightly reduced (26.4±3.0 to 21.8±2.7 mg/g. protein). Excretion of malondialdehyde (MDA) was increased only in Cd-injected hamsters (to 2.1±1.6 nM/L), and elevated MDA in renal cortical tissue was not reduced by the administration of TTHA (1041±105 vs 1104±358 nM/g protein). Glutathione (GSH) concentration in the renal cortex was significantly elevated after Cd administration and further increased after TTHA administration (5.5±2.1 to 9.8±2.0 μg/50 mg protein). There were no marked effects on creatinine clearance (Ccr) and hematocrit. Moreover, renal morphological changes were improved significantly by treatment with TTHA. We demonstrated the efficacy of TTHA in the treatment of Cd-induced nephropathy in hamsters. Although the precise mechanism of the TTHA effects on Cd-induced nephropathy has not been elucidated, it might involve GSH reducing the elevated MDA concentration in renal tissue.     

Selenium status of patients with Balkan endemic nephropathy

The selenium (Se) contents in common cereals in endemic and nonendemic areas in Serbia are very low. Plasma Se levels of both patients and healthy subjects, were also low, reflecting low Se intakes. Patients with Balkan endemic nephropathy (BEN) had significantly lower (p<0.05) plasma Se levels than healthy individuals, both from regions close to endemic areas, and from Belgrade. Mean plasma Se of BEN patients was slightly but insignificantly higher in samples taken immediately after dialysis than in those taken before, suggesting that very little of the Se present in plasma is dialyzable. Plasma SeGSH-Px activities before and after hemodialysis in both BEN and Nonendemic chronic renal failure (NCRF) patients were not significantly different, but BEN patients had lower enzyme activities than those with NCRF and healthy controls. In BEN patients, a significant correlation between plasma Se and SeGSH-Px activity was found. NCFR patients were with diagnoses: TBC of kidneys, chronic glomerulonephritis, chronic pyelonephritis, and polycystic kidneys.     

MMF联合泼尼松治疗成人特发性膜性肾病的疗效及安全性研究

目的:探究吗替麦考酚酯(MMF)联合泼尼松(Pre)治疗成人特发性膜性肾病(IMN)的疗效及安全性。方法:选取2015.06-2017.06我院收治的102例行IMN患者列为研究对象,将患者按随机数字表法以1:1比例分为对照组与观察组,每组各51例,对照组患者使用Pre进行治疗,观察组患者使用MMF+Pre进行治疗,治疗12个月。比较两组治疗12个月后疗效,治疗前、治疗后6个月及12个月后肾功能相关指标[24 h尿蛋白定量(24 h UP)、血清胱抑素C(CysC)、血清尿素氮(BUN)、血清肌酐(Scr)、血清白蛋白(Alb)]、脂代谢指标[总胆固醇(TC)、甘油三酯(TG)],并记录用药间期出现的药物不良反应。结果:治疗12个月后,研究组患者总有效率为90.20%,显著高对照组74.51%(P0.05);治疗6个月、12个月后,两组患者24 h UP、Cys C、TC、TG水平较治疗前均依次显著下降而Alb水平显著上升(P0.05),且观察组上述指标与同期对照组对比差异显著(P0.05);而两组BUN和Scr水平较治疗前差异不显著(P0.05),两组对比无统计学意义(P0.05)。治疗期间,观察组患者药物不良反应率为11.76%,显著低于对照组27.45%(P0.05)。结论:应用MMF联合泼尼松治疗成人IMN疗效更佳,可显著改善患者肾功能,并改善患者脂代谢,药物方案安全性较高,具有较高应用价值。     

西格列汀通过增加肾组织中SOCS 1和Podocalyxin的表达改善糖尿病肾病大鼠肾功能

目的:探讨西格列汀对糖尿病肾病大鼠肾功能及肾组织中细胞因子信号传导负调控因子1(Suppressors of cytockine signaling,SOCS 1)和足细胞特异蛋白抗体(Podocalyxin)表达的影响。方法:将大鼠随机分为4组:对照组,模型组,西格列汀组和贝那普利组。模型组、西格列汀组和贝那普利组采用腹腔注射链脲佐菌素建立模型,对照组给予腹腔注射等量生理盐水。造模成功后,西格列汀组(n=8)和贝那普利组(n=8)分别灌胃给予7 mg/kg/d的西格列汀和贝那普利。模型组(n=8)和对照组(n=10)均给予等体积的蒸馏水灌胃,连续8周。检测并对比各组大鼠代谢相关指标,肾组织纤维化程度指标,肾组织中炎症因子水平以及Podocalyxin、SOCS 1和结蛋白(Desmin)表达。结果:干预8周后,与对照组对比,模型组空腹血糖、糖化血红蛋白、甘油三酯、总胆固醇、24 h尿蛋白排泄率、肌酐、体重、肾组织转化生长因子-β1(Transforming growth factor,TGF-β1)、白介素(Interleukin,IL)-6、IL-1β、SOCS 1和Desmin水平均显著增加,Ⅳ型胶原蛋白(Collagen-Ⅳ,C-Ⅳ)、纤维连接蛋白(Fibronectin,FN)、层黏连蛋白(Laminin,LN)和Podocalyxin水平显著降低(P0.05);与模型组对比,西格列汀组和厄贝沙坦组空腹血糖、糖化血红蛋白、甘油三酯、总胆固醇、24 h尿蛋白排泄率、肌酐、体重、肾组织TGF-β1、IL-6、IL-1β和Desmin水平均显著降低,Podocalyxin和SOCS 1蛋白表达增加(P0.05)。但厄贝沙坦组与西格列汀组以上各指标对比差异无统计学意义(P0.05)。结论:西格列汀可能通过增加Podocalyxin和SOCS 1蛋白表达,降低肾组织中炎症因子和Desmin蛋白表达,进而改善糖尿病肾病大鼠肾纤维化和肾功能。     

特发性膜性肾病患者外周血中性粒细胞-淋巴细胞比值的临床与病理价值分析

摘要 目的：探讨外周血中性粒细胞与淋巴细胞比值（NLR）在特发性膜性肾病（IMN）中的临床及病理价值。方法：收集2017年1月至2019年12月确诊为IMN患者221例作为IMN组,将2019年7月至2019年9月体检且尿常规和肾功能指标正常的87例健康体检者作为正常对照组,计算每个研究对象的NLR值,比较两组间NLR值的差异。记录IMN患者的血生化指标及患者的肾脏病理分期及纤维化程度,并且根据MDRD公式计算肾小球滤过率(eGFR),分析NLR与IMN患者的血生化指标及病理特征的相关性。ROC曲线分析外周血NLR评估IMN患者肾间质纤维化的敏感性和特异性。结果：IMN组外周血NLR值高于对照组,差异有统计学意义（P<0.05）。外周血NLR值与IMN患者年龄和肾间质纤维化有关联（P均<0.05）,但与IMN患者性别及肾脏病理分期无关联（P均>0.05）。IMN外周血NLR值与IMN患者hs-CRP、SCr、BUN呈正相关（P<0.05）,与eGFR呈负相关（P<0.05）,与ESR、UA、TP、Alb、24小时蛋白尿定量均无相关性（P均>0.05）。不同程度肾间质纤维化的IMN患者外周血NLR值不同,差异有统计学意义（P<0.05）,且肾间质纤维化程度在1、2、3级时,纤维化程度越重,NLR值越大;3个级别间两两比较,差异均有统计学意义（P均<0.05）。外周血NLR值预测IMN患者肾间质纤维化的ROC曲线下面积为0.715[95%CI(0.626,0.803)],其截断值为1.858时,灵敏度为68.6%,特异度为66.7%。结论：外周血NLR可作为IMN肾脏功能水平的一个有效评价指标,且与IMN患者肾间质纤维化有关,可作为判断肾间质纤维化的参考指标。