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。     

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。     

姜黄素防治肾脏疾病的机制研究进展

姜黄素(curcumin)是提取于植物中的酮类天然化合物，具有抗炎、抗氧化、抗癌等作用。因其具有不良反应少、作用靶点广泛等优点，在各种肾脏疾病如肾炎、急/慢性肾损伤、肾纤维化等中发挥保护作用，并具有改善药物或有毒物质引起的肾脏损伤、减轻化疗药物对肾脏的损害和协同放化疗抗肾脏肿瘤的作用，近年来已成为肾脏疾病治疗的研究焦点，然而其潜在的作用机制及治疗作用以及后续的临床应用仍需进一步总结和探索。本文从病理生理的角度出发，系统综述了姜黄素在各种肾脏疾病中的作用及其潜在的机制，为后续的研究以及临床应用提供线索和依据。     

调控性细胞死亡在肾脏缺血再灌注损伤中的研究进展

肾脏上皮细胞死亡是肾脏缺血再灌注损伤引起的一种明显的病理现象,而最新研究发现调控性细胞死亡在肾脏缺血再灌注损伤中发挥着重要作用。本文就程序性坏死、铁死亡和细胞焦亡等调控性细胞死亡的相关通路、调节剂和相互作用以及在肾脏缺血再灌注损伤中的作用进行综述,以期对肾脏缺血再灌注损伤的预防和治疗提供理论基础。     

非编码RNA在调控外源化学物致肾损伤中的作用

外源性化学物质所引起的肾脏损害称为中毒性肾病或化学性肾损伤,其发病机制十分复杂,目前为止尚未完全阐明。现有的研究表明,其可能主要与氧化应激、炎症反应、凋亡或坏死、上皮间质化等过程相关。非编码RNA(non-coding RNAs,ncRNAs)是指不能翻译成蛋白质的一大类功能性RNA分子。近年来,以微小RNA(micro RNA,miRNA)和长链非编码RNA(long non-coding RNA,lncRNA)为代表的ncRNA研究发现,其对基因表达和信号通路的转导具有非常重要的调控作用,并具有调节外源化合物代谢,影响外源性化合物的肝肾毒性等功能。现主要围绕近几年非编码RNA在外源化学物致肾脏损伤相关研究中的研究成果,探讨药物、重金属、化学毒物致肾脏损伤过程中ncRNAs的表达差异,及ncRNA在调控化学性肾损伤相关信号通路中的作用机制,并且讨论它们在诊断和治疗过程中作为潜在标志物的前景。     

心脏手术围术期的血糖波动与术后急性肾损伤

心脏手术围术期高血糖与术后并发症的关系已经得到大量研究,高血糖与术后肾功能损伤的关系存在着不同的观点,但是对于围术期血糖水平的波动与术后肾损伤的研究甚少。本文概述了心脏手术围术期血糖水平波动对术后肾功能损伤的影响,简要分析其损伤机制。研究表明,多种因素可以增加围术期血糖水平的波动,对多项围术期高血糖是否增加术后肾功能损伤的研究争议分析发现,围术期血糖水平的波动对术后肾损伤的发生起到潜在作用,其损伤机制主要在于引起氧化应激和血流动力学的波动。相信围术期血糖水平的波动对术后肾功能损伤的影响的进一步的研究,将有助于降低心脏手术后急性肾损伤患者术后并发症的发生率。     

铁死亡相关机制及其在肾脏相关疾病中的研究进展

铁死亡是近年来新发现的一种铁依赖的区别于细胞凋亡、坏死、焦亡的程序性细胞死亡方式,其主要特点为铁离子累积与脂质过氧化的发生.研究表明,铁死亡在急性肾损伤、肾癌等肾脏相关疾病中起重要作用,但其确切机制尚未被完全揭示.随着铁死亡相关机制研究的不断发展,铁死亡在肾脏相关疾病治疗方面表现出良好的应用前景.本文对铁死亡相关机制及...     

肾脏有机阳离子转运体2在急性肾损伤中病理生理调控的研究进展

有机阳离子转运体2(organic cation transporter 2,OCT2)是溶质转运体(solute carriers,SLC)超家族中SLC22A家族的重要成员之一。肾小管上皮细胞基底膜侧表达的OCT2在维持机体内环境平衡方面起着重要作用,是肾脏主动分泌众多内、外源性有机阳离子型化合物(包括环境毒素、药物以及内源性代谢产物等)的主要转运体。在急性肾损伤(acute kidney injury,AKI)期间,OCT2功能与表达的改变对其底物的清除具有巨大的影响,可导致药物的药代动力学过程发生改变,从而影响药物的安全性和有效性。现就OCT2的结构与分布、生理作用与调控机制以及在各种因素诱导的AKI中的功能与表达变化和病理生理调控等方面进行综述,旨在为临床合理用药提供参考。     

肾小管脂毒性在糖尿病肾病发病机制中的研究进展

糖尿病肾病(diabetic nephropathy,DN)是糖尿病的重要并发症，是终末期肾病的重要病因。DN患者常伴脂质代谢紊乱。脂代谢紊乱可致肾小管内脂质分布异常，引起肾脏脂肪堆积、脂滴积累、肾小管损伤等一系列“脂毒性”现象，进而诱发DN肾脏炎症、纤维化等病理改变。作为肾脏中的高耗能结构，肾小管脂代谢产能对维持其正常生理功能具有重大意义。脂质能量代谢在DN发病机制中发挥不可或缺的作用，本文从胆固醇代谢引起DN肾小管脂毒性、脂肪酸代谢引起DN肾小管脂毒性、脂代谢异常在肾小管与肾小球间的“串扰”作用以及肾小管脂毒性靶向药物治疗等方面进行阐述，旨在为今后临床防治DN新角度与新方案的提出提供参考。     

线粒体损伤与急性肾损伤的研究进展

线粒体是有多种重要功能的细胞器,而肾小管上皮细胞又富含线粒体,越来越多的证据表明线粒体损伤对急性肾损伤(acute kidney injury,AKI)的发病有着十分重要的作用。近来对于线粒体产能外的功能研究,如线粒体分裂融合、线粒体生成、线粒体自噬等逐渐深入,使得对AKI发病机制及防治手段有更深入的探究。本文就急性肾损伤中线粒体功能的改变、衰老相关的线粒体损伤以及可能的干预靶点的研究进展作一综述。     

Shilajit potentiates the effect of chemotherapeutic drugs and mitigates metastasis induced liver and kidney damages in osteosarcoma rats

Osteosarcoma is a primary malignant cancer of the bone identified by the direct formation of osteoid tissue or immature bone by cancer cells. The liver and kidneys represent two major secondary organs to which osteosarcoma metastasizes. In this study, we assessed Shilajit, a phytomineral diffusion traditionally used in Ayurvedic medicine, for its possible protective effects against metastasis induced liver and kidney damages in an osteosarcoma rat model. Osteosarcoma rats displayed typical dysregulation of serum levels of hepatic and renal functional markers (p < 0.05) including aspartate aminotransferase (AST)* and alanine aminotransferase (ALT), alkaline phosphatase (ALP), total proteins, albumin, bilirubin, creatinine, urea, and uric acid. Changes in functional markers were also positively correlated with marked histopathological alterations in liver and kidney tissues. Whereas Shilajit's treatment of osteosarcoma rates in combination with CMF (cyclophosphamide, methotrexate, and 5-fluorouracil) chemotherapy drug cocktail significantly (p < 0.05) reversed the studied functional markers to their near-normal levels. Co-treatment of shilajit and drug cocktails also markedly alleviated histopathological changes in liver and kidney tissues. Correlation co-efficient analysis of hepatic and renal functional markers revealed a significant inter-association among these markers. Collectively, present data indicate that shilajit may potentiate the effects of chemotherapy drugs and mitigate the metastasis-induced liver and kidney damage in osteosarcoma. Thus, the findings of this study substantiate the beneficial health effects of shilajit and promote its regular consumption.     

“Systemic apoptotic response” after thermal burns

The systemic pathophysiologic changes following thermal injuries affect multiple organs and body systems leading to clinical manifestations including shock, intestinal alterations, respiratory and renal failure, immunosuppression and others. Recent advances in the comprehension of mechanisms underlying systemic complications of thermal injuries have contributed to uncover part of the cellular and molecular basis that underlie such changes. Recently, programmed cell death (apoptosis) has been considered playing an important role in the development of such pathological events. Therefore, investigators utilizing animal models and clinical studies involving human primates have produced a large body of information suggesting that apoptosis is associated with most of the tissue damages triggered by severe thermal injuries. In order to draw the attention on the important role of apoptosis on systemic complications of thermal injuries, in this review we describe most of these studies, discuss possible cellular and molecular mechanisms and indicate ways to utilize them for the development of therapeutic strategies by which apoptosis may be prevented or counteracted.     

Organ Histopathological Changes and its Function Damage in Mice Following Long-term Exposure to Lanthanides Chloride

Due to increasing applications of lanthanides (Ln) in industry and daily life, numerous studies confirmed that Ln exposure may result in organ damages in mice and rats, while very few studies focused on several organs damages simultaneously. In order to compare the toxicity of Ln on organs, mice were exposed to LaCl(3), CeCl(3), and NdCl(3) of a dose of 20 mg/kg body weight for consecutive 60 days, respectively, then histopathological changes of liver, kidney, and heart, and their function were investigated. The results showed that long-term exposure to Ln caused cell necrosis and basophilia of liver, ambiguity of renal tubule architecture, congestion of blood vessel and capillary of kidney, and heart hemorrhage. The histopathological changes of liver, kidney, and heart in mice caused by Ce(3+) was most severe; the effect by Nd(3+) was slighter than Ce(3+) but more severe than La(3+). The assay of serum biochemical parameters suggested that Ln exposure severely impaired the functions of liver, kidney, and myocardium in mice. These findings suggested that long-term exposure to Ln resulted in histopathological changes of liver, kidney, and heart, and their function damages. Therefore, we thought that long-term application of the products containing Ln on human should be cautious.     

Kruppel‐like factor 4 improves obesity‐related nephropathy through increasing mitochondrial biogenesis and activities

Obesity is positively linked to multiple metabolic complications including renal diseases. Several studies have demonstrated Kruppel‐like factor 4 (KLF4) participated in renal dysfunction and structural disorders in acute kidney injuries, but whether it affected the process of chronic kidney diseases was unknown. Therefore, present study was to disclose the role of renal KLF4 in dietary‐induced renal injuries and underlying mechanisms in obesity. Through utilizing high‐fat diet‐fed mice and human renal biopsies, we provided the physiological roles of KLF4 in protecting against obesity‐related nephropathy. Decreased levels of renal KLF4 were positively correlated with dietary‐induced renal dysfunction, including increased levels of creatinine and blood urea nitrogen. Overexpression of renal KLF4 suppressed inflammatory response in palmitic acid‐treated mouse endothelial cells. Furthermore, overexpressed KLF4 also attenuated dietary‐induced renal functional disorders, abnormal structural remodelling and inflammation. Mechanistically, KLF4 maintained renal mitochondrial biogenesis and activities to combat obesity‐induced mitochondrial dysfunction. In clinical renal biopsies and plasma, the renal Klf4 level was negatively associated with circulating levels of creatinine but positively associated with renal creatinine clearance. In conclusions, the present findings firstly supported that renal KLF4 played an important role in combating obesity‐related nephropathy, and KLF4/mitochondrial function partially determined the energy homeostasis in chronic kidney diseases.     

Study of histopathological and molecular changes of rat kidney under simulated weightlessness and resistance training protective effect

To explore the effects of long-term weightlessness on the renal tissue, we used the two months tail suspension model to simulate microgravity and investigated the simulated microgravity on the renal morphological damages and related molecular mechanisms. The microscopic examination of tissue structure and ultrastructure was carried out for histopathological changes of renal tissue morphology. The immunohistochemistry, real-time PCR and Western blot were performed to explore the molecular mechanisms associated the observations. Hematoxylin and eosin (HE) staining showed severe pathological kidney lesions including glomerular atrophy, degeneration and necrosis of renal tubular epithelial cells in two months tail-suspended rats. Ultrastructural studies of the renal tubular epithelial cells demonstrated that basal laminas of renal tubules were rough and incrassate with mitochondria swelling and vacuolation. Cell apoptosis in kidney monitored by the expression of Bax/Bcl-2 and caspase-3 accompanied these pathological damages caused by long-term microgravity. Analysis of the HSP70 protein expression illustrated that overexpression of HSP70 might play a crucial role in inducing those pathological damages. Glucose regulated protein 78 (GRP78), one of the endoplasmic reticulum (ER) chaperones, was up-regulated significantly in the kidney of tail suspension rat, which implied that ER-stress was associated with apoptosis. Furthermore, CHOP and caspase-12 pathways were activated in ER-stress induced apoptosis. Resistance training not only reduced kidney cell apoptosis and expression of HSP70 protein, it also can attenuate the kidney impairment imposed by weightlessness. The appropriate optimization might be needed for the long term application for space exploration.     

Role of free-radical reactions in liver diseases.

Role of free-radical reactions is most significant in toxic liver injuries. Two traditional groups of liver injuries induced by drugs and chemicals are distinguished, 1. direct toxic type and 2. idiosyncratic type. Liver injury of direct toxic type is generally developed following toxin exposure, it is dose dependent, incubation period is short, and the injury often affects other organs (e.g. kidney). Direct toxins frequently cause typical zonal necrosis usually without concomitant signs of hypersensitivity. It is typical of idiosyncratic reaction that it appears only in a shorter period of exposure, it cannot be predicted, it is not dose-dependent, its incubation period varies and sometimes (in one-fourth of cases) it is accompanied by extrahepatic symptoms of hypersensitivity (fever, leukocytosis, eosinophilia, rashes), its morphologic picture shows great variety. A part of direct toxins is toxic itself, in the other part the basic compound is not toxic but it changes into toxic metabolites in the liver. Liver is well-protected against free-radicals developing in the organism: it is one of our best antioxidant supplied organs. It is probably due to the one of the important tasks of liver, namely detoxication of drugs, chemicals and toxic materials, with subsequent release of free-radicals. It is proved by the fact that in normal bile peroxidized lipids produced by free-radical chain reactions can also be detected. The pathologic free-radical reactions and one of their sequelae, peroxidation of lipids (LPO) do not necessarily cause cell and tissue damage. Antioxidant protection of cells and tissues is able to prevent free-radical injury and it enables, that the already developed damages become reversible. According to recent investigations, the lipid peroxidation, caused by free-radical reactions, or covalent binding of radical products to biomolecules does not lead directly to cellular destruction, only via further reactions. Such intermediary steps can be the phospholipase A2 activation, accumulation of lysophosphatides, poly-ADP-ribose polymerase repair enzyme activation, following oxidative damage of DNA, with subsequent NAD and ATP depletion. Its significance may be that the irreversible cellular and tissue damage can be prevented perhaps not only by administration of antioxidants, but also by compounds (e.g. phospholipase A2 inhibitors) affecting the above-mentioned biochemical mechanisms.     

Cellular senescence in the aging and diseased kidney

The program of cellular senescence is involved in both the G1 and G2 phase of the cell cycle, limiting G1/S and G2/M progression respectively, and resulting in prolonged cell cycle arrest. Cellular senescence is involved in normal wound healing. However, multiple organs display increased senescent cell numbers both during natural aging and after injury, suggesting that senescent cells can have beneficial as well as detrimental effects in organismal aging and disease. Also in the kidney, senescent cells accumulate in various compartments with advancing age and renal disease. In experimental studies, forced apoptosis induction through the clearance of senescent cells leads to better preservation of kidney function during aging. Recent groundbreaking studies demonstrate that senescent cell depletion through INK-ATTAC transgene-mediated or cell-penetrating FOXO4-DRI peptide induced forced apoptosis, reduced age-associated damage and dysfunction in multiple organs, in particular the kidney, and increased performance and lifespan. Senescence is also involved in oncology and therapeutic depletion of senescent cells by senolytic drugs has been studied in experimental and human cancers. Although studies with senolytic drugs in models of kidney injury are lacking, their dose limiting side effects on other organs suggest that targeted delivery might be needed for successful application of senolytic drugs for treatment of kidney disease. In this review, we discuss (i) current understanding of the mechanisms and associated pathways of senescence, (ii) evidence of senescence occurrence and causality with organ injury, and (iii) therapeutic strategies for senescence depletion (senotherapy) including targeting, all in the context of renal aging and disease.     

Pharmacokinetics of Drugs in Cachectic Patients: A Systematic Review

Cachexia is a weight-loss process caused by an underlying chronic disease such as cancer, chronic heart failure, chronic obstructive pulmonary disease, or rheumatoid arthritis. It leads to changes in body structure and function that may influence the pharmacokinetics of drugs. Changes in gut function and decreased subcutaneous tissue may influence the absorption of orally and transdermally applied drugs. Altered body composition and plasma protein concentration may affect drug distribution. Changes in the expression and function of metabolic enzymes could influence the metabolism of drugs, and their renal excretion could be affected by possible reduction in kidney function. Because no general guidelines exist for drug dose adjustments in cachectic patients, we conducted a systematic search to identify articles that investigated the pharmacokinetics of drugs in cachectic patients.     

Induced pluripotent stem cells for therapy personalization in pediatric patients:Focus on drug-induced adverse events

Adverse drug reactions(ADRs) are major clinical problems, particularly in special populations such as pediatric patients. Indeed, ADRs may be caused by a plethora of different drugs leading, in some cases, to hospitalization, disability or even death. In addition, pediatric patients may respond differently to drugs with respect to adults and may be prone to developing different kinds of ADRs,leading, in some cases, to more severe consequences. To improve the comprehension, and thus the prevention, of ADRs, the set-up of sensitive and personalized assays is urgently needed. Important progress is represented by the possibility of setting up groundbreaking patient-specific assays. This goal has been powerfully achieved using induced pluripotent stem cells(iPSCs). Due to their genetic and physiological species-specific differences and their ability to be differentiated ideally into all tissues of the human body, this model may be accurate in predicting drug toxicity, especially when this toxicity is related to individual genetic differences. This review is an up-to-date summary of the employment of iPSCs as a model to study ADRs, with particular attention to drugs used in the pediatric field. We especially focused on the intestinal, hepatic,pancreatic, renal, cardiac, and neuronal levels, also discussing progress in organoids creation. The latter are three-dimensional in vitro culture systems derived from pluripotent or adult stem cells simulating the architecture and functionality of native organs such as the intestine, liver, pancreas, kidney, heart,and brain. Based on the existing knowledge, these models are powerful and promising tools in multiple clinical applications including toxicity screening,disease modeling, personalized and regenerative medicine.     

Mitochondrial Modulation by Epigallocatechin 3-Gallate Ameliorates Cisplatin Induced Renal Injury through Decreasing Oxidative/Nitrative Stress,Inflammation and NF-kB in Mice

Cancer chemotherapy drug cisplatin is known for its nephrotoxicity. The aim of this study is to investigate whether Epigallocatechin 3-Gallate (EGCG) can reduce cisplatin mediated side effect in kidney and to understand its mechanism of protection against tissue injury. We used a well-established 3-day cisplatin induced nephrotoxicity mice model where EGCG were administered. EGCG is a major active compound in Green Tea and have strong anti-oxidant and anti-inflammatory properties. EGCG protected against cisplatin induced renal dysfunction as measured by serum creatinine and blood urea nitrogen (BUN). EGCG improved cisplatin induced kidney structural damages such as tubular dilatation, cast formation, granulovaculoar degeneration and tubular cell necrosis as evident by PAS staining. Cisplatin induced kidney specific mitochondrial oxidative stress, impaired activities of mitochondrial electron transport chain enzyme complexes, impaired anti-oxidant defense enzyme activities such as glutathione peroxidase (GPX) and manganese superoxide dismutase (MnSOD) in mitochondria, inflammation (tumor necrosis factor α and interleukin 1β), increased accumulation of NF-κB in nuclear fraction, p53 induction, and apoptotic cell death (caspase 3 activity and DNA fragmentation). Treatment of mice with EGCG markedly attenuated cisplatin induced mitochondrial oxidative/nitrative stress, mitochondrial damages to electron transport chain activities and antioxidant defense enzyme activities in mitochondria. These mitochondrial modulations by EGCG led to protection mechanism against cisplatin induced inflammation and apoptotic cell death in mice kidney. As a result, EGCG improved renal function in cisplatin mediated kidney damage. In addition to that, EGCG attenuated cisplatin induced apoptotic cell death and mitochondrial reactive oxygen species (ROS) generation in human kidney tubular cell line HK-2. Thus, our data suggest that EGCG may represent new promising adjunct candidate for cisplatin.