中草药干预糖尿病肾病炎症的作用

随着糖尿病发病率逐年升高,糖尿病肾病成为导致慢性肾脏疾病和终末期肾脏疾病的主要原因。而目前控制血糖及抑制肾素-血管紧张素系统的药物治疗,并不能有效防止糖尿病肾病进展。近年来发现,慢性低水平炎症和免疫系统激活在糖尿病性肾病的发生及发展中起着至关重要的作用。明确糖尿病肾病进展中的炎症机制将有助于确定新的潜在靶点及研发抗炎治疗策略。越来越多的证据表明,中药治疗可以有效改善糖尿病性肾病的高血糖和蛋白尿,并能延缓其进展成为终末期肾病。糖尿病肾病动物实验和体外研究证实中药复方、中草药提取物和中药单体具有调节炎症介质的作用。本文旨在归纳总结文献中与糖尿病肾病肾损伤相关的炎症分子和途径,并探讨中草药靶向抗炎治疗糖尿病肾病的作用。     

肾素-血管紧张素系统在糖尿病肾病肾脏足细胞损伤中的作用

糖尿病肾病(diabetic kidney disease,DKD)作为诱发终末期肾脏病(end-stage renal disease,ESRD)的主要原因,至今其病理机制仍不十分清楚.DKD病程中蛋白尿持续增多并伴随肾素-血管紧张素系统(renin-angiotensin system,RAS)过度激活.阻断RAS能改善蛋白尿,有良好的临床肾脏保护作用.足细胞表达RAS的各成员,作为肾小球滤过的最后屏障,其损伤与蛋白尿的发生关系密切.本文就RAS与足细胞损伤在DKD病理中作用作一简单综述.     

糖尿病肾病致凝血异常的研究

糖尿病(DM)已成为世界性的常见病,其发病率高,并且随着生活水平的改善,其发病率必然还会进一步加剧。血管病变是DM的重要并发症之一,糖尿病肾病(DN)是糖尿病常见且严重的微血管并发症,与血栓形成密切相关。糖尿病肾病的进展伴随着体内凝血活性和抗凝活性的失调,同时激活自身免疫系统,发生炎症反应。炎症应答过程中释放的炎症因子损伤肾小球内皮细胞,导致抗凝活性减弱。DN患者体内血细胞激活,微粒形成增多会加强凝血活性。此外,纤溶酶抑制剂(PAI-1)与纤溶酶激活剂(t PA)的失衡会引起纤溶系统紊乱。这三个方面引起DN患者体内的高凝状态加重,并因此加速肾功能恶化,导致肾小球率过滤降低,系膜基质增多,最终引起肾小球硬化及终末期肾脏疾病。本文就糖尿病肾病致凝血异常的发生机制做一综述。     

脂代谢异常对肾病的影响

肾脏疾病发展为慢性肾衰竭是个不可逆的过程,脂质代谢的异常,对肾病患者具有重要的影响。多项实验已经证实,即使在肾病的早期阶段,也会出现不同程度的脂质及脂类代谢的异常,高密度脂蛋白(HDL)、低密度脂蛋白(LDL)、脂联素、瘦素等脂类代谢相关物质发生改变,不仅对血浆脂代谢产生影响,对于肾小球及肾小管的结构及功能也会有一定的损伤作用。肾病患者,如肾病综合征、慢性肾衰竭等疾病,多数有肾小球及肾小管间质的损伤,肾脏的脂毒性加重肾单位的破坏。随着人们对于慢性肾脏病认识的逐渐深入,降脂治疗的普遍应用,人们普遍认为改善血浆中脂类的水平,对于肾病的治疗,尤其对于慢性肾衰竭的预防具有重要作用。     

内皮祖细胞在支架术后再内皮化中应用的研究进展

足细胞是附着在肾小球基底膜外的高度分化的上皮细胞,在维持肾小球滤过屏障完整性及限制血浆蛋白的滤出方面均发挥重要作用。近年来,在糖尿病肾病的研究中发现,足细胞损伤对蛋白尿及肾小球硬化等病理变化均明显相关。本文就糖尿病肾病时足细胞损伤的特点作一简要概述,为以后的相关研究奠定基础。     

线粒体动力学调控机制及其在肾脏病理生理学中的作用

线粒体是一种动态变化的细胞器,它通过不断的融合、分裂来维持线粒体的形态、数量和功能稳定,这一过程称为线粒体动力学,是线粒体质量控制的重要机制。线粒体的过度融合与分裂都会导致线粒体动力学的稳态失衡,引起线粒体功能障碍,导致细胞损伤甚至死亡。肾脏的生理活动主要由线粒体供能,线粒体动力学稳态失衡影响着线粒体功能,与急性肾损伤、糖尿病肾病等肾脏疾病密切相关。本文对线粒体动力学的调节、线粒体动力学稳态失衡如何导致线粒体损伤以及线粒体损伤对肾脏病理生理学的影响进行综述,以加深对肾脏疾病中线粒体作用的理解与认识。     

糖尿病肾病蛋白尿发生机制的研究进展

糖尿病肾病蛋白尿的发生发展是多因素综合作用的结果.虽然蛋白尿的确切病因仍未清楚,但基本是由肾脏血流动力学改变、肾小球滤过屏障异常、多种生长因子、细胞因子、免疫炎症因子异常表达以及肾小管异常等多个因素综合所致.在分子水平上,氧化应激是糖尿病并发症发生的早期事件.此外,内皮细胞结构异常和功能紊乱以及肾小管重吸收功能异常可能也参与了蛋白尿的发生发展.本文着重探讨糖尿病肾病蛋白尿发生的细胞及分子机制研究进展,为更好的防治糖尿病肾病提供有力的依据.     

足细胞病与相关循环因子的表达

肾小球足细胞的损伤不仅是遗传性肾小球病的发病基础,还在很多后天的肾小球疾病中发挥重要作用。常见的足细胞病以微小病变性肾病(Minimal Change Disease,MCD)和局灶阶段性肾小管硬化(Focal Segmental glomerulosclerosis,FSGS)为主,有实验证明,足细胞损伤同时参与了各种不同类型的肾小球疾病,比如糖尿病肾病,HIV相关肾病,膜性肾病及其他获得性肾小球病等,因此,了解足细胞病损伤的机制尤为重要。临床观察提出局灶节段行肾小球硬化患者体内可能存在一种与大量蛋白尿发生有关的循环因子,相关的动物实验和体外观察同时也证实了循环因子的存在。越来越多的研究支持T细胞功能不全,细胞因子异常释放可能是循环因子的来源之一。如果能对患者循环因子进行检测,借助它来指导治疗方案的选择(免疫抑制剂、血浆置换),可能成为局灶节段行肾小球硬化诊断和治疗中的一个突破。本文以国内外研究文献为基础,对文献资料进行分析、归纳和总结,综述了足细胞病中相关循环因子的表达,探讨足细胞病发生及复发的机理,为足细胞病的定向治疗提供帮助。     

PPARγ在糖尿病肾病中的保护作用

糖尿病肾病(d iabetic nephropathy,DN)是一种由糖尿病导致的肾功能降低的慢性疾病,以蛋白尿、肾小球肥大、肾小球滤过率降低和肾纤维化为主要特征,是导致终末期肾脏疾病的主要病因,也是糖尿病患者死亡的主要原因。过氧物酶体增殖体激活受体γ(peroxisome proliferator-activatedreceptor,γPPARγ)是PPAR核受体家族中的一员,在许多生理过程中起重要作用。噻唑烷二酮(TZDs)是PPARγ的激动剂。在过去的十多年中,大量研究表明TZDs对DN的发生和发展具有明显的保护作用,其主要机制包括改善胰岛素抵抗、降低血糖、降低血压等间接保护作用和抑制肾间质纤维化、保护足细胞等直接保护作用。本文将对PPARγ在DN中的肾脏保护作用及其潜在机制进行综述与讨论。     

α3β1整合素在糖尿病大鼠肾脏的表达及其与足细胞减少的关系

目的动态观察1型糖尿病大鼠肾小球足细胞及粘附分子α3β1整合素表达的时相变化,探讨α3β1整合素与足细胞减少,蛋白尿发生的关系。方法以1型糖尿病大鼠为动物模型,于第2,4,6,8,12周以肾小球足细胞表面标志物肾母细胞瘤抑制基因（Wilm’Stumorl,WTl）水平检测足细胞密度变化,同时以免疫比浊法检测大鼠24h尿微量白蛋白水平,及RT—PCR法测定各组大鼠肾皮质α3β1整合素mRNA的表达水平。结果与对照组相比,糖尿病大鼠从2周起出现明显的足细胞密度减低,24h尿量和尿微量白蛋白增加,4周开始出现血尿素氮升高,8周开始出现血清肌酐升高,并且随着病程进展,足细胞密度和24h尿微量白蛋白水平变化更加明显。α3β1整合素mRNA水平从第2周起比正常对照组明显降低,而在4周、8周和12周并没有呈现持续的减少。结论在糖尿病肾病早期,α3β1整合素水平降低可能是导致足细胞减少和蛋白尿发生的主要原因,而随着糖尿病病程进展,可能有其他机制参与,从而导致了糖尿病肾病足细胞减少、蛋白尿发生和肾小球损伤的进展。     

Modulation of antibody-mediated glomerular injury in vivo by bacterial lipopolysaccharide, tumor necrosis factor, and IL-1

We have investigated the effects of LPS, human rTNF (hrTNF) and human rIL-1 beta (hrIL-1 beta) pretreatment on the intensity of antibody-mediated injury in vivo by using a passive model of anti-glomerular basement membrane (GBM) antibody-mediated nephritis in rats. The experiments show that all three pretreatments exacerbate injury in this model whether judged by albuminuria or the prevalence of glomerular capillary thrombi. The effect on albuminuria was dose dependent with all three treatments. The lowest effective dose of LPS was 0.025 microgram while those for hrTNF and hrIL-1 beta were 0.4 microgram and 0.5 microgram, respectively. All three pretreatments also increased the prevalence of glomerular capillary thrombi which were rare in rats injected with anti-GBM antibodies without pretreatment. LPS pretreatment appeared to be more effective in causing glomerular capillary thrombi than hrTNF or hrIL-1 beta and this was reflected in the correlations between albuminuria and the proportion of glomeruli with capillary thrombi. This relation was linear for all three pretreatments but the slope was appreciably greater for rats pretreated with LPS (0.37) when compared with results from rats given either hrTNF (0.22) or hrIL-1 beta (0.29). Pretreatment of nephritic rats with both cytokines increased the slope to 0.42 demonstrating a synergistic effect. The synergism of hrTNF with hrIL-1 beta was also demonstrated by the effective doses needed to induce albuminuria which was evident in rats treated with 0.05 microgram of IL-1 beta and 0.4 microgram of TNF. Neither the cytokines nor LPS caused clinical, morphologic, or biochemical evidence of renal toxicity when given alone in the dose used here but they did cause a transient increase in the number of neutrophils marginated in glomerular capillaries. Pretreatment of rats with LPS or cytokines increased the glomerular neutrophil influx after anti-GBM antibodies by roughly sixfold. Our experiments show that TNF and IL-1 can increase the severity of glomerular injury in nephritis; they may be important in modulating glomerular injury clinically.     

Advances in pathogenetic mechanisms of diabetic nephropathy.

The diabetic epidemic that is being experienced around the world has many ramifications. Since diabetes is the most common cause of end stage renal disease in the United States and the Western world, we can expect the increase in prevalence to continue. Minority individuals with diabetes suffer a disproportionately high incidence of diabetic nephropathy leading to end stage renal disease. The data suggest that aggressive medical management should be their mainstay of therapy. In the past five years, our knowledge of the mechanisms involved in the pathology of diabetic glomerulosclerosis has greatly expanded. Transforming growth factor (TGF)-beta still maintains a key role in the pathogenesis. However, many of the signaling mechanisms have now been described. Furthermore, TGF-beta may also function to damage glomerular epithelial cells or podocytes, resulting in podocyteuria and proteinuria that worsen with progressive diabetic nephropathy. Additionally, TGF-beta upregulation in diabetes may cause injury or transformation of tubular epithelial cells that contribute to interstitial fibrosis. The use of thiazolidinediones in type 2 diabetes is associated with improvement in insulin sensitivity, as well as improvement in albuminuria. The mechanisms by which these ligands function remain unclear, but there may be several targets that could include mesangial cells and podocytes.     

Monocyte Chemotactic Protein-1 (MCP-1) in Patients with Chronic Schistosomiasis Mansoni: Evidences of Subclinical Renal Inflammation

The aim of this study is to investigate renal markers and the biomarker MCP-1 in patients with schistosomiasis mansoni. This is a cross-sectional study with 85 patients aged 5 to 48 years, with a confirmed diagnosis of schistosomiasis mansoni through the Kato-Katz method. The patients were divided in three groups: control (G-I); infected by S. mansoni before treatment (G-II) and infected by S. mansoni after treatment (G-III). Renal function was evaluated by tubular and glomerular biomarkers and through urinary MCP-1. Patients’ mean age was 23.2±13 years. There was no statistically significant difference between the groups regarding tubular and glomerular function evaluated through the traditional biomarkers. MCP-1 was higher in G-II and G-III, when compared to G-I; p=0.009 and p=0.007, respectively. There was no difference when comparing groups G-II and G-III (p=0.892). Although it was not different among the groups, there was a significant correlation between albuminuria and MCP-1. There was a significant increase in urinary MCP-1 levels in patients with schistosomiasis mansoni, which was associated with albuminuria. This protein has a role in the recruitment of monocytes to injury and inflammation sites . The increase of MCP-1 in the urine evidences that there is silent renal inflammation in these patients and the inflammatory status is not interrupted by specific treatment of the offending agent. Our findings suggest that urinary MCP-1 can be a sensitive marker of renal injury in patients with schistosomiasis mansoni.     

Diabetic kidney disease in FVB/NJ Akita mice: temporal pattern of kidney injury and urinary nephrin excretion

Akita mice are a genetic model of type 1 diabetes. In the present studies, we investigated the phenotype of Akita mice on the FVB/NJ background and examined urinary nephrin excretion as a marker of kidney injury. Male Akita mice were compared with non-diabetic controls for functional and structural characteristics of renal and cardiac disease. Podocyte number and apoptosis as well as urinary nephrin excretion were determined in both groups. Male FVB/NJ Akita mice developed sustained hyperglycemia and albuminuria by 4 and 8 weeks of age, respectively. These abnormalities were accompanied by a significant increase in systolic blood pressure in 10-week old Akita mice, which was associated with functional, structural and molecular characteristics of cardiac hypertrophy. By 20 weeks of age, Akita mice developed a 10-fold increase in albuminuria, renal and glomerular hypertrophy and a decrease in the number of podocytes. Mild-to-moderate glomerular mesangial expansion was observed in Akita mice at 30 weeks of age. In 4-week old Akita mice, the onset of hyperglycemia was accompanied by increased podocyte apoptosis and enhanced excretion of nephrin in urine before the development of albuminuria. Urinary nephrin excretion was also significantly increased in albuminuric Akita mice at 16 and 20 weeks of age and correlated with the albumin excretion rate. These data suggest that: 1. FVB/NJ Akita mice have phenotypic characteristics that may be useful for studying the mechanisms of kidney and cardiac injury in diabetes, and 2. Enhanced urinary nephrin excretion is associated with kidney injury in FVB/NJ Akita mice and is detectable early in the disease process.     

NPHS2 gene polymorphism aggravates renal damage caused by focal segmental glomerulosclerosis with COL4A3 mutation

Focal segmental glomerulosclerosis (FSGS), a type of primary glomerular disease, is the leading cause of end-stage renal disease (ESRD). Several studies have revealed that certain single-gene mutations are involved in the pathogenesis of FSGS; however, the main cause of FSGS has not been fully elucidated. Homozygous mutations in the glomerular basement membrane gene can lead to early renal failure, while heterozygous carriers develop renal failure symptoms late. Here, molecular genetic analysis of clinical information collected from clinical reports and medical records was performed. Results revealed that nephrosis 2 (NPHS2) gene polymorphism aggravated renal damage in three FSGS families with heterozygous COL4A3 mutation, leading to early renal failure in index patients. Our findings suggest that COL4A3 and NPHS2 may have a synergistic effect on renal injury caused by FSGS. Further analysis of the glomerular filtration barrier could help assess the cause of kidney damage. Moreover, a detailed analysis of the glomerular basement membrane-related genes and podocyte structural proteins may help us better understand FSGS pathogenesis and provide insights into the prognosis and treatment of hereditary glomerulonephropathy.     

Long Term Metabolic Syndrome Induced by a High Fat High Fructose Diet Leads to Minimal Renal Injury in C57BL/6 Mice

Metabolic syndrome can induce chronic kidney disease in humans. Genetically engineered mice on a C57BL/6 background are highly used for mechanistic studies. Although it has been shown that metabolic syndrome induces cardiovascular lesions in C57BL/6 mice, in depth renal phenotyping has never been performed. Therefore in this study we characterized renal function and injury in C57BL/6 mice with long-term metabolic syndrome induced by a high fat and fructose diet (HFFD). C57BL/6 mice received an 8 months HFFD diet enriched with fat (45% energy from fat) and drinking water enriched with fructose (30%). Body weight, food/water consumption, energy intake, fat/lean mass ratio, plasma glucose, HDL, LDL, triglycerides and cholesterol levels were monitored. At 3, 6 and 8 months, renal function was determined by inulin clearance and measure of albuminuria. At sacrifice, kidneys and liver were collected. Metabolic syndrome in C57BL/6 mice fed a HFFD was observed as early 4 weeks with development of type 2 diabetes at 8 weeks after initiation of diet. However, detailed analysis of kidney structure and function showed only minimal renal injury after 8 months of HFFD. HFFD induced moderate glomerular hyperfiltration (436,4 µL/min vs 289,8 µL/min; p-value=0.0418) together with a 2-fold increase in albuminuria only after 8 months of HFFD. This was accompanied by a 2-fold increase in renal inflammation (p-value=0.0217) but without renal fibrosis or mesangial matrix expansion. In addition, electron microscopy did not show alterations in glomeruli such as basal membrane thickening and foot process effacement. Finally, comparison of the urinary peptidome of these mice with the urinary peptidome from humans with diabetic nephropathy also suggested absence of diabetic nephropathy in this model. This study provides evidence that the HFFD C57BL/6 model is not the optimal model to study the effects of metabolic syndrome on the development of diabetic kidney disease.     

Role of Nox4 in murine models of kidney disease

Nox4 is a hydrogen peroxide-producing NADPH oxidase highly expressed in the kidney which has been linked to epithelial cell injury and diabetic-induced cellular dysfunction in cultured cells. The role of the enzyme for renal pathology in vivo, however, is unclear. To address this, three experimental animal models of renal injury (streptozotocin diabetes I, unilateral ureteral ligation (UUO), and 5/6 nephrectomy (5/6Nx)) were studied in either Nox4-inducible (Nox4(?/?)) or constitutive knockout (Nox4(-/-)) mice. Nox4 contributed more than 80% of diphenylene iodonium-sensitive H(2)O(2) formation of freshly isolated tubules determined by Amplex Red assay. In streptozotocin diabetes, acute deletion of Nox4 by tamoxifen-activated cre-recombinase increased albuminuria, whereas matrix deposition was similar between WT and Nox4(?/?) mice. Interestingly, renal Nox4 expression, mainly localized to tubular cells, decreased in the course of diabetes and this was not associated with a compensatory upregulation of Nox1 or Nox2. In the UUO model, renal expression of ICAM1, connective tissue growth factor, and fibronectin were higher in kidneys of Nox4(?/?) than control mice. Also in this model, levels of Nox4 decreased in the course of the disease. In the 5/6Nx model, which was performed in SV129 and SV129-Nox4(-/-) mice, no difference in the development of hypertension and albuminuria was found between the strains. Collectively, the first in vivo data of the kidney do not support the view that Nox4 is a main driver of renal disease. It rather appears that under specific conditions Nox4 may even slightly limit injury and disease progression.     

Salt loading produces severe renal hemodynamic dysfunction independent of arterial pressure in spontaneously hypertensive rats

We have previously shown that salt excess has adverse cardiac effects in spontaneously hypertensive rats (SHR), independent of its increased arterial pressure; however, the renal effects have not been reported. In the present study we evaluated the role of three levels of salt loading in SHR on renal function, systemic and renal hemodynamics, and glomerular dynamics. At 8 wk of age, rats were given a 4% (n = 11), 6% (n = 9), or 8% (n = 11) salt-load diet for the ensuing 8 wk; control rats (n = 11) received standard chow (0.6% NaCl). Rats had weekly 24-h proteinuria and albuminuria quantified. At the end of salt loading, all rats had systemic and renal hemodynamics measured; glomerular dynamics were specially studied by renal micropuncture in the control, 4% and 6% salt-loaded rats. Proteinuria and albuminuria progressively increased by the second week of salt loading in the 6% and 8% salt-loaded rats. Mean arterial pressure increased minimally, and glomerular filtration rate decreased in all salt-loaded rats. The 6% and 8% salt-loaded rats demonstrated decreased renal plasma flow and increased renal vascular resistance and serum creatinine concentration. Furthermore, 4% and 6% salt-loaded rats had diminished single-nephron plasma flow and increased afferent and efferent arteriolar resistances; glomerular hydrostatic pressure also increased in the 6% salt-loaded rats. In conclusion, dietary salt loading as low as 4% dramatically deteriorated renal function, renal hemodynamics, and glomerular dynamics in SHR independent of a minimal further increase in arterial pressure. These findings support the concept of a strong independent causal relationship between salt excess and cardiovascular and renal injury.     

Glycoprotein hyposialylation gives rise to a nephrotic-like syndrome that is prevented by sialic acid administration in GNE V572L point-mutant mice

Mutations in the key enzyme of sialic acid biosynthesis, UDP-N-acetylglucosamine 2-epimerase/N-acetyl-mannosamine kinase, result in distal myopathy with rimmed vacuoles (DMRV)/hereditary inclusion body myopathy (HIBM) in humans. Sialic acid is an acidic monosaccharide that modifies non-reducing terminal carbohydrate chains on glycoproteins and glycolipids, and it plays an important role in cellular adhesions and interactions. In this study, we generated mice with a V572L point mutation in the GNE kinase domain. Unexpectedly, these mutant mice had no apparent myopathies or motor dysfunctions. However, they had a short lifespan and exhibited renal impairment with massive albuminuria. Histological analysis showed enlarged glomeruli with mesangial matrix deposition, leading to glomerulosclerosis and abnormal podocyte foot process morphologies in the kidneys. Glycan analysis using several lectins revealed glomerular epithelial cell hyposialylation, particularly the hyposialylation of podocalyxin, which is one of important molecules for the glomerular filtration barrier. Administering Neu5Ac to the mutant mice from embryonic stages significantly suppressed the albuminuria and renal pathology, and partially recovered the glomerular glycoprotein sialylation. These findings suggest that the nephrotic-like syndrome observed in these mutant mice resulted from impaired glomerular filtration due to the hyposialylation of podocyte glycoproteins, including podocalyxin. Furthermore, it was possible to prevent the nephrotic-like disease in these mice by beginning Neu5Ac treatment during gestation.     

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.