Involvement of heparan sulfate in the renoprotective effects of imidapril,an angiotensin-converting enzyme inhibitor,in diabetic db/db mice

Abstract

We investigated the renoprotective effects of imidapril hydrochloride ((-)-(4?S)-3-[(2?S)-2-[[(1?S)-1-ethoxycarbonyl-3-phenylpropyl] amino] propionyl]-1-methyl-2-oxoimidazolidine-4-carboxylic acid hydrochloride, imidapril), an angiotensin-converting enzyme inhibitor, in a diabetic animal model. We used BKS.Cg-+Lepr^db/+Lepr^db (db/db) mice, a genetic animal model of obese type 2 diabetes. Diabetic db/db mice suffered from glomerular hyperfiltration, albuminuria and hypoalbuminemia. Oral administration of 5?mg/kg/day of imidapril for 3 weeks suppressed renal hyperfiltration, reduced albuminuria and normalized hypoalbuminemia. Imidapril did not influence body weights, blood pressure or blood glucose concentrations in db/db mice. Urinary excretion of heparan sulfate (HS) in non-treated 11-week-old db/db mice was significantly lower than that in age-matched non-diabetic db/+m mice. HS is a component of HS proteoglycans, which are present in glomerular basement membranes and glycocalyx of cell surfaces. Reduced urinary HS excretion indicated glomerular HS loss in db/db mice. Imidapril increased urinary excretion of HS to concentrations observed in db/+m mice, indicating that imidapril prevented the loss of renal HS. These results suggest that imidapril ameliorates renal hyperfiltration and loss of renal contents of HS. Improvement of filtration function and maintenance of HS, which is an important structural component of glomeruli, may contribute to renoprotective effects of imidapril.     

DIBc nano metal-organic framework improves biochemical and pathological parameters of experimental chronic kidney disease

BackgroundThe growing morbidity and mortality rate of chronic kidney disease (CKD) has forced researchers to find more efficient strategies for controlling this disease. Studies have proven the important role of alteration in iron, zinc and selenium metabolism in CKD pathological process. Nanotechnology, through synthetizing nano metal-organic framework (NMOF) structures, can be employed as a valuable strategy for using these trace elements as the key for modification and improvement of CKD-related pathological events. After proving the anti-diabetic property of DIBc NMOF (which contains selenium and zinc) in the previous study, the impact of this NMOF on some important biochemical and pathological parameters of CKD was evaluated in the current study.MethodsKnowing that diabetic nephropathy (DN) is the leading cause of CKD, male wistar rats were selected and given a high fat diet for 2 weeks and then were injected with streptozotocin (35 mg/kg) to induce DN. Six weeks after streptozotocin injection, DIBc or metformin treatment started and continued for 8 weeks.ResultsEight weeks of DIBc treatment decreased plasma fasting blood glucose, blood urea nitrogen, uric acid, malondialdehyde (MDA) and HOMA-IR index compared to DN control and metformin groups. This NMOF significantly reduced urinary albumin excretion rate, MDA and 8-isoprostane, while it increased creatinine clearance in comparison to the above-mentioned groups. Renal histo-pathological images indicated that DIBc ameliorated glomerular basement membrane thickening and wrinkling, mesangial matrix expansion and hypercellularity and presence of intra-cytoplasmic hyaline droplets in proximal cortical tubules of kidney samples.ConclusionThe results showed the therapeutic effect of DIBc on important biochemical and histo-pathological parameters of CKD, so this NMOF could be regarded as a promising novel anti-CKD agent.     

活性氧簇对蛋白尿的影响

蛋白尿不仅反映肾小球损伤,而且是一个独立的导致肾脏病变进展的主要因素,任何能够使蛋白尿减少的治疗干预都有利于减慢肾脏疾病的进展,遗传性蛋白尿性肾病是由于基因突变所致,获得性肾病大量蛋白尿成因目前尚未阐明。免疫异常,炎症介质及氧化应激反应均可导致肾损伤。氧自由基是肾损伤的主要介质,它作为强氧化剂是造成蛋白尿的重要原因之一。活性氧分子(ROS)可以通过降解肾小球乙酰肝素硫酸盐、肾小球基底膜Ⅳ型胶原富含赖氨酸的NCl区域发生交联、损伤足细胞破坏肾小球滤过屏障及与其他活性因子作用增强血清蛋白的渗透性等作用,造成蛋白尿。本文就近年来人们对活性氧造成蛋白尿的机制的研究做一综述,便于帮助医务工作者更好的了解和治疗蛋白尿性肾病。     

甲状腺功能减退症合并慢性肾功能衰竭5例临床分析

目的：提出一些关于早期诊治甲状腺功能减退症合并慢性肾功能不全的建议。方法：回顾性分析我科2000-2006年住院患者中甲状腺功能减退症合并肾功能衰竭病例5例,比较其临床表现和相关检查并分析其诊疗经过。结果：二种疾病不仅在其发生发展上有一定联系,而且在临床表现和相关检查上也有相似之处。二种疾病都可出现浮肿、贫血、乏力、纳差、心包积液、蛋白尿和不同程度的肾功能不全。二者合并出现时临床表现更加复杂多样,增加了临床诊断的难度。结论：在诊治此类疾病时要注意临床表现的一些细节,如心力衰竭时的相对缓脉、与肾功能不全不相适应的贫血、难治性心包积液、不明原因的肾功能损害等,以便早期正确诊治,提高诊疗水平。     

Regulation of heparanase by albumin and advanced glycation end products in proximal tubular cells

Diabetic nephropathy is one of the main causes of end-stage renal disease, in which the development of tubular damage depends on factors such as high glucose levels, albuminuria and advanced glycation end-product. In this study, we analyzed the involvement of heparanase, a heparan sulfate glycosidase, in the homeostasis of proximal tubular epithelial cells in the diabetic milieu. In vitro studies were performed on a wild-type and stably heparanase-silenced adult tubular line (HK2) and HEK293. Gene and protein expression analyses were performed in the presence and absence of diabetic mediators. Albumin and advanced glycation end-product, but not high glucose levels, increased heparanase expression in adult tubular cells via the AKT/PI3K signaling pathway. This over-expression of heparanase is then responsible for heparan sulfate reduction via its endoglycosidase activity and its capacity to regulate the heparan sulfate-proteoglycans core protein. In fact, heparanase regulates the gene expression of syndecan-1, the most abundant heparan sulfate-proteoglycans in tubular cells. We showed that heparanase is a target gene of the diabetic nephropathy mediators albumin and advanced glycation end-product, so it may be relevant to the progression of diabetic nephropathy. It could take part in several processes, e.g. extracellular-matrix remodeling and cell-cell crosstalk, via its heparan sulfate endoglycosidase activity and capacity to regulate the expression of the heparan sulfate-proteoglycan syndecan-1.     

Albuminuria associated with CD2AP knockout mice is primarily due to dysfunction of the renal degradation pathway processing of filtered albumin

Here we address the assumption that the massive intact albuminuria accompanying mutations of structural components of the slit diaphragm is due to changes in glomerular permeability. The increase in intact albumin excretion rate in Cd2ap knockout mice by >100-fold was not accompanied by equivalent changes in urine flow rate, glomerular filtration rate or increases in dextran plasma clearance rate, which demonstrates that changes in glomerular permeability alone could not account for the increase in intact albumin excretion. The albuminuria could be accounted for by inhibition of the tubule degradation pathway associated with degrading filtered albumin. There are remarkable similarities between these results and all types of podocytopathies in acquired and toxin-induced renal disease, and nephrotic states seen in mice with podocyte mutations.     

西格列汀对2 型糖尿病患者微量白蛋白尿影响的研究

目的:研究西格列汀对2型糖尿病患者微量白蛋白尿的影响,分析其可能机制和临床应用价值。方法:选取160例伴微量白蛋白尿的2型糖尿病患者,随机分为西格列汀组和其他药物组,各80例。比较两组患者治疗前和治疗3个月后血糖水平、尿微量白蛋白、超敏C反应蛋白及血浆还原型谷胱甘肽水平。结果:经3个月治疗,两组患者空腹血糖、餐后2 h血糖、Hb A1c均较治疗前下降,但差异无明显统计学意义(P0.05);西格列汀治疗组患者尿微量白蛋白和血浆Hs-CRP水平明显下降,血浆还原型谷胱甘肽水平明显升高,与其他口服药物治疗组相比差异具有统计学意义(P0.05)。结论:西格列汀可能通过改善机体炎症状态,降低氧化和应激水平等机制降低2型糖尿病患者的尿微量白蛋白水平。     

2型糖尿病患者心脏代谢指数与白蛋白尿的关系研究

摘要 目的：探讨2型糖尿病（T2DM）患者心脏代谢指数（CMI）与白蛋白尿的关系。方法：选取2012年2月~2020年7月期间在江苏大学附属医院内分泌代谢科就诊且被诊断为T2DM的患者555例,收集患者的临床资料。根据CMI不同数值将患者分为低CMI（L-CMI）组（n=185）、中CMI（M-CMI）组（n=185）和高CMI（H-CMI）组（n=185）,按照尿白蛋白/肌酐比值（UACR）将研究对象分为正常白蛋白尿组（n=294）、微量白蛋白尿组（n=209）和大量白蛋白尿组（n=52）,然后对CMI与T2DM患者发生异常白蛋白尿的关系进行分析,通过受试者工作特征（ROC）曲线评估CMI对T2DM患者发生异常白蛋白尿的预测价值。结果：不同UACR组的收缩压（SBP）、舒张压（DBP）、体质量指数（BMI）、CMI、甘油三酯（TG）、总胆固醇（TC）、高密度脂蛋白胆固醇（HDL-C）、糖化血红蛋白（HbA1c）、空腹血糖（FPG）、空腹胰岛素（FINS）、空腹C肽（FC-P）、稳态模型评估胰岛素抵抗指数（HOMA-IR）、尿素氮（BUN）、血尿酸（SUA）、血肌酐（Scr）及肾小球滤过率（eGFR）比较均有统计学差异（P＜0.05）。L-CMI组、M-CMI组、H-CMI组异常白蛋白尿发生比例分别为21.08%、42.70%、77.30%,异常白蛋白尿发生比例呈显著递增趋势（P＜0.05）。Spearman秩相关分析结果显示,T2DM患者UACR与FINS、BUN、 CMI、Scr、SUA、SBP、DBP、BMI、TG、TC、HbA1c、FPG、FC-P、HOMA-IR呈正相关（P<0.05）,与eGFR、HDL-C呈负相关（P<0.05）。多元线性回归分析显示,CMI对UACR的影响强度最大（P＜0.05）。Logistic回归分析结果显示,年龄、SBP、CMI、TC、LDL-C及HbA1c是T2DM患者发生异常白蛋白尿的独立危险因素（P＜0.05）。CMI预测异常白蛋白尿发生的曲线下面积为0.801,预测异常白蛋白尿的敏感性、特异性分别为68.60%、76.90%。结论：T2DM患者异常白蛋白尿发生风险与CMI密切相关,提示CMI有望成为临床上糖尿病肾病（DKD）的预测指标。     

Activation of the Nlrp3 inflammasome by mitochondrial reactive oxygen species: A novel mechanism of albumin-induced tubulointerstitial inflammation

Albuminuria is not only an important marker of chronic kidney disease but also a crucial contributor to tubulointerstitial inflammation (TIF). In this study, we determined whether activation of the Nlrp3 inflammasome is involved in albuminuria induced-TIF and the underlying mechanisms of inflammasome activation by mitochondrial reactive oxygen species (mROS). We established an albumin-overload induced rat nephropathy model characterised by albuminuria, renal infiltration of inflammatory cells, tubular dilation and atrophy. The renal expression levels of the Nlrp3 inflammasome, IL-1β and IL-18 were significantly increased in this animal model. In vitro, albumin time- and dose-dependently increased the expression levels of the Nlrp3 inflammasome, IL-1β and IL18. Moreover, the silencing of the Nlrp3 gene or the use of the caspase-1 inhibitor Z-VAD-fmk significantly attenuated the albumin-induced increase in IL-1β and IL-18 expression in HK2 cells. In addition, mROS generation was elevated by albumin stimulation, whereas the ROS scavenger N-acetyl-l-cysteine (NAC) inhibited Nlrp3 expression and the release of IL-1β and IL-18. In kidney biopsy specimens obtained from patients with IgA nephropathy, Nlrp3 expression was localised to the proximal tubular epithelial cells, and this result is closely correlated with the extent of proteinuria and TIF. In summary, this study demonstrates that albuminuria may serve as an endogenous danger-associated molecular pattern (DAMP) that stimulates TIF via the mROS-mediated activation of the cytoplasmic Nlrp3 inflammasome.     

Documento de consenso para la detección y manejo de la enfermedad renal crónica

Chronic kidney disease (CKD) is an important global health problem, involving to 10% of the Spanish population, promoting high morbidity and mortality for the patient and an elevate consumption of the total health resources for the National Health System. This is a summary of an executive consensus document of ten scientific societies involved in the care of the renal patient, that actualizes the consensus document published in 2007. The central extended document can be consulted in the web page of each society. The aspects included in the document are: Concept, epidemiology and risk factors for CKD. Diagnostic criteria, evaluation and stages of CKD, albuminuria and glomerular filtration rate estimation. Progression factors for renal damage. Patient remission criteria. Follow-up and objectives of each speciality control. Nephrotoxicity prevention. Cardio-vascular damage detection. Diet, life-style and treatment attitudes: hypertension, dyslipidaemia, hyperglycemia, smoking, obesity, hyperuricemia, anemia, mineral and bone disorders. Multidisciplinary management for Primary Care, other specialities and Nephrology. Integrated management of CKD patient in haemodialysis, peritoneal dialysis and renal transplant patients. Management of the uremic patient in palliative care. We hope that this document may be of help for the multidisciplinary management of CKD patients by summarizing the most updated recommendations.