An update on renal fibrosis: from mechanisms to therapeutic strategies with a focus on extracellular vesicles

The increasing prevalence of chronic kidney disease (CKD) is a major global public health concern. Despite the complicated pathogenesis of CKD, renal fibrosis represents the most common pathological condition, comprised of progressive accumulation of extracellular matrix in the diseased kidney. Over the last several decades, tremendous progress in understanding the mechanism of renal fibrosis has been achieved, and corresponding potential therapeutic strategies targeting fibrosis-related signaling pathways are emerging. Importantly, extracellular vesicles (EVs) contribute significantly to renal inflammation and fibrosis by mediating cellular communication. Increasing evidence suggests the potential of EV-based therapy in renal inflammation and fibrosis, which may represent a future direction for CKD therapy.

Research progress of extracellular vesicles in the treatment of renal disease / 生理学报

Extracellular vesicles (EVs) are lipid bilayer-enclosed structures containing diverse bioactive cargoes that play a major role in intercellular communication in both physiological and pathological conditions. Currently, the field of EV-based therapy has been rapidly growing, and two main therapeutic uses of EVs can be surmised: (i) exploiting stem cell-derived EVs as therapeutic agents; and (ii) employing EVs as natural therapeutic vectors for drug delivery. This review will discuss the recent advances in EV-based therapy in the treatment of renal disease.

Research progress of vascular endothelial growth factor-A and its isoforms in kidney disease / 生理学报

Vascular endothelial growth factor-A (VEGF-A) is a critical angiogenic factor which is mainly secreted from podocytes and epithelial cells in kidney and plays an important role in renal pathophysiology. In recent years, functions of different isoforms of VEGF-A and the new secretion approach via extracellular vesicles (EVs) have been identified. Thus, further understanding are needed for the role of VEGF-A and its isoforms in renal injury and repair. In this review, we summarized the expression, secretion and regulation of VEGF-A, its biological function, and the role of different isoforms of VEGF-A in the development of different renal diseases. Meanwhile, the research progress of VEGF-A as diagnostic marker and therapeutic target for renal diseases were discussed.

New advances in oxygen sensing and adaptive mechanism / 生理学报

Under the hypoxic condition, organs or cells trigger a series of reactions or responses to adapt to the physiological requirement. These responses involve a complex regulation at different levels from organs, in particular the kidney (producing erythropoietin), to cells throughout the body. Actually, the responses to hypoxia from adaption to injury largely depend on the degree and time of hypoxia. In the past two decades, with the discovery of hypoxia-inducible factor (HIF), the mechanisms of erythropoiesis regulation were elucidated gradually, which has provided a novel therapeutic strategy for hypoxia-related diseases, especially renal anemia. In this review we focus on the latest advances in oxygen sensing and adaptive mechanism.

Current insights into the role of HIF-PHD axis in renal anemia / 生理学报

Renal anemia, mainly caused by the deficiencies of erythropoietin (EPO) and iron metabolism disorder, is one of the most common complications of chronic kidney disease. Hypoxia-inducible factor (HIF) is a class of transcription factors responsible for maintaining homeostasis during oxygen deprivation. In normoxia, HIF is degraded by prolyl hydroxylase (PHD). While under hypoxic conditions, the hydroxylation activity of PHD is inhibited, and the cellular concentration of HIF is elevated, resulting in an increase in endogenous EPO production and iron absorption. Therefore, this regulating pathway, also termed as the HIF-PHD axis, has become a promising therapeutic target of treating renal anemia. Several innovative drugs acting as selective HIF-PHD inhibitors have been successfully developed in the past years, and some of them are undergoing clinical trials. In this review, we will introduce the definition and regulatory mechanism of HIF-PHD axis, as well as current insights into its physiologic and therapeutic role in renal anemia.

Urinary biomarkers for chronic kidney disease: a focus on gene transcript / 生理学报

Chronic kidney disease (CKD) is becoming an alarming health burden worldwide, however, there is still lack of early biomarkers and effective treatment options. Thus, in the upcoming era of precision medicine, searching for the sensitive, non-invasive biomarkers has been the cornerstone and major challenge in the management of CKD. Urine contains rich biological information which could be an ideal source for non-invasive biomarkers of CKD. This review will discuss the recent advances in biomarker study from urine sediment, urine supernatant and urinary extracellular vesicles with special interest in gene transcript (miRNA, mRNA) biomarkers. Besides, the challenges and future directions for urinary gene transcript biomarker study will be discussed.

Urinary Biomarkers for Chronic Kidney Disease with a Focus on Gene Transcript / 中华医学杂志(英文版)

<p><b>Objective:</b>In the upcoming era of precision medicine, searching for the early, noninvasive biomarkers has been the cornerstone and major challenge in the management of chronic kidney disease (CKD). Urine contains rich biological information which could be the ideal source for noninvasive biomarkers of CKD. This review will discuss the recent advance in urinary biomarker.</p><p><b>Data Sources:</b>This review was based on data in articles published in the PubMed databases up to June 20, 2017, with the following keywords: "Chronic kidney disease", "Biomarker", and "Urine".</p><p><b>Study Selection:</b>Original articles and important reviews on urinary biomarker were selected for this review.</p><p><b>Results:</b>Urinary biomarker studies of CKD mainly focused on urine sediment, supernatant, and urinary extracellular vesicles. The gene transcript (microRNA [miRNA], messenger RNA [mRNA]) biomarkers have been recently shown with diagnostic potential for CKD reflecting kidney function and histological change. However, challenges regarding technique and data analysis need to be resolved before translation to clinic.</p><p><b>Conclusions:</b>Different fractions of urine contain rich information for biomarker discovery, among which urine (extracellular vesicles) mRNA, miRNA, might represent promising biomarker for CKD.</p>

Effect of Cordyceps sinensis powder on renal oxidative stress and mitochondria functions in 5/6 nephrectomized rats / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effect of Cordyceps sinensis (CS) powder on renal oxidative stress and mitochondria functions in 5/6 nephrectomized rats, and to primarily explore its possible mechanisms.</p><p><b>METHODS</b>Totally 30 male Sprague-Dawley rats were divided into the sham-operation group, the model group, and the treatment group by random digit table, 10 in each group. A chronic kidney disease (CKD) rat model was prepared by one step 5/6 nephrectomy. Rats in the treatment group were intragastrically administered with CS powder solution at the daily dose of 2 g/kg, once per day. Equal volume of double distilled water was intragastrically administered to rats in the sham-operation group and the model group. All medication lasted for 12 weeks. The general condition of rats, their body weight, blood pressure, 24 h proteinuria, urinary N-acetyl-β-D-glucosaminidase (NAG), serum creatinine (SCr) , and blood urea nitrogen (BUN) were assessed before surgery, at week 2, 4, 6, 8, 10, and 10 after surgery. Pathological changes of renal tissues were observed under light microscope. Morphological changes of mitochondria in renal tubular epithelial cells were observed under transmission electron microscope. Activities of antioxidant enzymes including reduced glutathione (GSH), manganese superoxide dismutase (MnSOD), and malondialdehyde (MDA) in fresh renal tissue homogenate were detected. Mitochondria of renal tissues were extracted to detect levels of mitochondrial membrane potential and changes of reactive oxygen species (ROS). And expressions of cytochrome-C (Cyto-C) and prohibitin in both mitochondria and cytoplasm of the renal cortex were also measured by Western blot.</p><p><b>RESULTS</b>(1) Compared with the sham-operation group, body weight was significantly decreased at week 2 (P <0. 01), but blood pressure increased at week 4 (P <0. 05) in the model group. Compared with the model group, body weight was significantly increased at week 12 (P <0. 01), but blood pressure decreased at week 8 (P < 0. 01) in the treatment group. (2) Compared with the sham-operation group, 24 h proteinuria, urinary NAG, blood SCr and BUN significantly increased in the model group (all P <0. 01). Compared with the model group, blood and urinary biochemical indices all significantly decreased in the treatment group (all P <0. 01). (3) Results of pathological renal scoring: Glomerular sclerosis index, scoring for tubulointerstitial fibrosis, degree of tubulointerstitial inflammatory infiltration were all obviously higher in the model group than in the sham-operation group (all P <0. 01). All the aforesaid indices were more obviously improved in the treatment group than in the model group (all P <0. 01). (4) Compared with the sham-operation group, activities of MnSOD and GSH-Px were significantly reduced, but MDA contents obviously increased in the renal cortex of the model group (all P <0. 01). Compared with the model group, activities of MnSOD and GSH-Px obviously increased (P <0. 05, P <0. 01), but MDA contents obviously decreased in the renal cortex of the treatment group (P <0. 01). (5) Compared with the sham-operation group, the mitochondrial membrane potential significantly decreased, but ROS levels significantly increased in the model group (all P <0.01). Compared with the model group, mitochondrial transmembrane potential increased in the treatment group, thereby inhibiting the tendency of increased production of ROS (both P < 0. 01). (6) Results of Western blot showed that, compared with the sham-operation group, expression levels of mitochondrial Cyto-C and Prohibitin were significantly reduced in the renal cortex (P <0. 01), but significantly elevated in the cytoplasm of the model group (P <0. 01). Compared with the model group, each index was obviously improved in the treatment group with statistical difference (P <0. 05, P <0. 01).</p><p><b>CONCLUSION</b>CS powder had renal protection, and its mechanism might partially depend on in- hibition of oxidative stress and protection for mitochondria.</p>

Inflammation accelerates lipid dysregulation mediated cardiac fibrosis through enhancing myocardial endothelial-to-mesenchymal transition / 中华心血管病杂志

<p><b>OBJECTIVE</b>Dyslipidemia and chronic inflammation are risk factors of cardiac fibrosis. This study was aimed to investigate their possible synergetic effects and underlying mechanisms on progression of cardiac fibrosis in apolipoprotein E knockout (ApoE -/-) mice.</p><p><b>METHODS</b>Twenty-four ApoE-/- mice were divided into normal chow diet (control), high fat diet (HFD group), and HFD plus subcutaneously injection of 10% casein (inflammation group) for 8 weeks. Lipid profile and serum amyloid A (SAA) were examined by clinical biochemical assays and Enzyme-Linked Immunosorbent Assay, respectively. Hematoxylin-eosin staining (HE) and Masson staining were used to evaluate the myocardial accumulation of lipid and collagen. Collagen I protein expression was detected by immunohistochemical staining. Endothelial-to-mesenchymal transition related protein expressions were determined by Western blot.</p><p><b>RESULTS</b>Serum SAA level was significantly higher in inflammation group [(127.42 ± 26.99) ng/ml] than in control [(15.40 ± 7.62) ng/ml] and HFD [(8.17 ± 0.72) ng/ml] group (all P < 0.01).However serum levels of triglyceride, total cholesterol, and low density lipoprotein (LDL) cholesterol were significantly higher in HFD group than in inflammation and control groups[TG (7.53 ± 2.05) mmol/L vs. (3.43 ± 0.79) mmol/L; TC (27.80 ± 3.99) mmol/L vs. (14.94 ± 1.92) mmol/L;LDL-C (11.56 ± 2.56) mmol/L vs. (9.46 ± 1.31) mmol/L, all P < 0.05) . Foam cell formation in cardiac vessels, myocardial collagen deposit, protein expressions of collagen I, CD31, and alpha-smooth muscle actin (α-SMA) were all significantly higher in inflammation group than in HFD group (all P < 0.05) suggesting that inflammation contributes to the phenotype endothelial-to-mesenchymal transition in heart.</p><p><b>CONCLUSION</b>Inflammation exacerbates dyslipidemia mediated cardiac fibrosis in ApoE-/- mice partly through enhancing myocardial endothelial-to-mesenchymal transition.</p>

Prevalence, awareness, treatment, and control of hypertension in the non-dialysis chronic kidney disease patients / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Data on the epidemiology of hypertension in Chinese non-dialysis chronic kidney disease (CKD) patients are limited. The aim of the present study was to investigate the prevalence, awareness, treatment, and control of hypertension in the non-dialysis CKD patients through a nationwide, multicenter study in China.</p><p><b>METHODS</b>The survey was performed in 61 tertiary hospitals in 31 provinces, municipalities, and autonomous regions in China (except Hong Kong, Macao, and Taiwan). Trained physicians collected demographic and clinical data and measured blood pressure (BP) using a standardized protocol. Hypertension was defined as systolic BP ≥ 140 mmHg and/or diastolic BP ≥ 90 mmHg, and/or use of antihypertensive medications. BP < 140/90 mmHg and < 130/80 mmHg were used as the 2 thresholds of hypertension control. In multivariate logistic regression with adjustment for sex and age, we analyzed the association between CKD stages and uncontrolled hypertension in non-dialysis CKD patients.</p><p><b>RESULTS</b>The analysis included 8927 non-dialysis CKD patients. The prevalence, awareness, and treatment of hypertension in non-dialysis CKD patients were 67.3%, 85.8%, and 81.0%, respectively. Of hypertensive CKD patients, 33.1% and 14.1% had controlled BP to < 140/90 mmHg and < 130/80 mmHg, respectively. With successive CKD stages, the prevalence of hypertension in non-dialysis CKD patients increased, but the control of hypertension decreased (P < 0.001). When the threshold of BP < 130/80 mmHg was considered, the risk of uncontrolled hypertension in CKD 2, 3a, 3b, 4, and 5 stages increased 1.3, 1.4, 1.4, 2.5, and 4.0 times compared with CKD 1 stage, respectively (P < 0.05). Using the threshold of < 140/90 mmHg, the risk of uncontrolled hypertension increased in advanced stages (P < 0.05).</p><p><b>CONCLUSIONS</b>The prevalence of hypertension Chinese non-dialysis CKD patients was high, and the hypertension control was suboptimal. With successive CKD stages, the risk of uncontrolled hypertension increased.</p>

Inhibition of integrin-linked kinase by angiotensin II receptor antagonist, irbesartan attenuates podocyte injury in diabetic rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Integrin-linked kinase (ILK) dysregulation is involved in the progression of diabetic nephropathy (DN). The aim of this study was to investigate the effects of angiotensin II receptor blocker (ARB), irbesartan, on ILK expression and podocyte injury in DN.</p><p><b>METHODS</b>DN was induced by the combined feeding of high-sucrose, high-fat diet and intra-peritoneal injection of low dose of streptozotocin (35 mg/kg) in spontaneously hypertensive rats. Diabetic rats were treated with irbesartan (50 mg×kg(-1)×d(-1)) by gavage for 8 weeks. The renal morphologic changes and podocyte injury were investigated by light and electron microscopy, and the ILK expression was evaluated by real-time RT-PCR and Western blotting analysis.</p><p><b>RESULTS</b>Diabetic rats exhibited with the similar clinical feature of type 2 DN. Morphologically, they were characterized by expansion of mesangial matrix, loss of podocyte and podocyte injury. Impressively, compared to controls, the ILK expression in diabetic rats were upregulated, which were positively correlated with both podocyte injury and albuminuria. Irbesartan significantly prevented ILK overexpression, along with the amelioration of podocyte injury and albuminuria.</p><p><b>CONCLUSIONS</b>ILK plays an important role in mediating podocyte injury in DN; irbesartan inhibits ILK upregulation and attenuates podocyte injury, which might offer a new insight into the role of ARB in preventing DN progression.</p>

Influence of irbesartan on the urinary excretion of cytokines in patients with chronic kidney disease / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The non-hemodynamic effects of angiotensin receptor blocker (ARB) in the delay of progression of chronic kidney disease (CKD) remain unclear. In this study, we investigated the influence of irbesartan on the urinary excretion of cytokines in patients with CKD.</p><p><b>METHODS</b>In this randomized perspective clinical trial, different doses of irbesartan (150 mg/d and 300 mg/d) were given to two groups of patients in a cross-over design. Blood pressure (BP), creatinine clearance (Ccr) and 24-hour proteinuria were examined. Urinary excretion of cytokines was determined by human inflammatory cytokine antibody array. A two-fold change in spot intensity was considered significant.</p><p><b>RESULTS</b>Urinary excretion of cytokines (granulocyte colony stimulating factor (GCSF), intercellular cell adhesion molecule-1 (ICAM-1), interferon γ (IFN-γ), interleukin 1β (IL-1b), IL-2, IL-6, IL-8, IL-11, IL-15 and macrophage inflammatory protein 1d (MIP-1d)) in group B (irbesartan 300 mg/d) was significantly decreased in comparison to group A (irbesartan 150 mg/d) after 8-week treatment. In group A, 8 weeks of treatment induced a two- to nine-fold reduction in urinary cytokine levels (GCSF, GM-CSF, IFN-γ, IL-1a, IL-11, IL-12p40, MCP-2, MIP-1a), while increasing the dosage to 300 mg/d further decreased the excretion of GCSF, GM-CSF, IL-12p40, MCP-2 and MIP-1a by week 18. There was no significant difference in BP or Ccr between the two groups. However, 24-hour proteinuria was significantly reduced in both groups, and in group A the reduction was dose dependent.</p><p><b>CONCLUSION</b>Irbesartan offers additional renoprotection in a dose-dependent manner by reducing pro-inflammatory cytokines excretion in the urine of CKD patients.</p>

Application of systems biology to the study of chronic kidney disease / 中华医学杂志(英文版)

Chronic kidney disease (CKD) is a major public health problem that affects about 10% of the general population. Current approaches to characterize the category and progression of CKD are normally based on renal histopathological results and clinical parameters. However, this information is not sufficient to predict CKD progression risk reliably or to guide preventive interventions. Nowadays, the appearance of systems biology has brought forward the concepts of "-omics" technologies, including genomics, transcriptomics, proteomics, and metabolomics. Systems biology, together with molecular analysis approaches such as microarray analysis, genome-wide association studies (GWAS), and serial analysis of gene expression (SAGE), has provided the framework for a comprehensive analysis of renal disease and serves as a starting point for generating novel molecular diagnostic tools for use in nephrology. In particular, analysis of urinary mRNA and protein levels is rapidly evolving as a non-invasive approach for CKD monitoring. All these systems biological molecular approaches are required for application of the concept of "personalized medicine" to progressive CKD, which will result in tailoring therapy for each patient, in contrast to the "one-size-fits-all" therapies currently in use.

Risk factors for acute kidney injury in patients undergoing allogeneic hematopoietic stem cell transplantation / 癌症

<p><b>BACKGROUND AND OBJECTIVE</b>Allogeneic hematopoietic cell transplantation (allo-HSCT) is a potent procedure for the treatment of hematologic diseases, yet it is associated with high risks of treatment-related complications. Except for transplant-related organ toxicities, renal insufficiencies which emerge earlier significantly limit patients' long survival. To analyze risk factors for acute kidney injury (AKI), we conducted a retrospective cohort study of 96 patients undergoing HSCT.</p><p><b>METHODS</b>During the first 100 days after allo-HSCT, all patients were evaluated for renal function by measuring serum creatinine clearance and glomerular filtration rate (GFR) with a classification below: Grade 0 (<25%, decline in creatinine clearance), Grade 1 (≥25% decline in creatinine clearance but <2-fold increase in serum creatinine), Grade 2 (≥2-fold rise in serum creatinine but no need for dialysis), and Grade 3 (≥2-fold rise in serum creatinine and need for dialysis). Cox regression model was used to calculate the hazard ratios (HRs) of demographic data, clinical variables, and risk factors for AKI.</p><p><b>RESULTS</b>Twenty-eight (29.2%) patients occurred Grades 1-3 renal dysfunction (Grade 1, 14 patients; Grade 2, 12 patients; Grade 3, 2 patients), and ratios of early kidney injury increased in high-risk malignancy group (HR = 2.945, 95% confidence interval (CI)=1.293-6.421), patients treated with myeloablative conditioning regimen (HR=2.463, 95% CI=1.757-4.320), and patients with acute GVHD (HR=3.553, 95% CI=1.809-6.978), sepsis (HR=3.215, 95% CI=1.189-6.333 ), or hepatic veno-occlusive disease (VOD) (HR=3.487, 95% CI=1.392-6.524). Whereas, HLA histocompatibility showed no striking increased risk for acute renal injury (HR=1.684, 95% CI=0.648-4.378). The survival rate was lower in patients with severe nephrotoxicity (21.4%) than in patients without nephrotoxicity (70.6%) (P=0.001).</p><p><b>CONCLUSIONS</b>Nephrotoxicity is the primary risk factor for AKI, severely impacting on survival. Sorts of risk factors mentioned will be useful for evaluation for kidney function of patients undergoing allo-HSCT.</p>

Acute renal failure after hematopoietic stem cell transplantation-review / 中国实验血液学杂志

Hematopoietic stem cell transplantation is a common procedure for the treatment of hematologic malignancies and some non-malignant hematologic disorders. In addition to other transplant-related organ toxicities, acute renal failure is a common complication following allogeneic hematopoietic stem cell transplantation. This review discusses the incidence, etiology, risk factors, and prognosis of renal failure associated with three commonly used transplantation models: myeloablative autologous, myeloablative allogeneic, and non-myeloablative allogeneic hematopoietic stem cell transplantations.

Microinflammation is involved in the dysfunction of arteriovenous fistula in patients with maintenance hemodialysis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Vascular access (VA) dysfunction is a major clinical complication in the hemodialysis population and has a direct effect on dialysis outcome. This study was conducted to explore the role of microinflammation in the VA dysfunction in maintenance hemodialysis patients.</p><p><b>METHODS</b>Forty-seven patients (male 35 and female 12) receiving maintenance hemodialysis were included for this study. They were divided into three groups: group 1 (n = 15), patients with initial hemodialysis and new arteriovenous fistula (AVF); group 2 (n = 18), patients treated with hemodialysis for long term with well-functional VA; group 3 (n = 14), maintenance hemodialysis patients with VA dysfunction. Biochemical parameters and serum tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) were determined. High-sensitivity C-reactive protein (hs-CRP) was determined by latex-enhanced immuno-nephelometric method. Tissues of radial artery were taken from group 1 and group 3 for the histological study. Expression of CD68 and MCP-1 in the radial artery was determined by immunohistochemistry.</p><p><b>RESULTS</b>Serum hs-CRP in group 3 was significantly higher than those in group 1 and group 2 ((7.40 +/- 2.42) mg/L vs (4.21 +/- 1.62) mg/L and (5.04 +/- 3.65) mg/L, P < 0.01 and P < 0.05, respectively). Serum TNF-alpha in group 3 was significantly higher than those in group 1 and group 2 ((64.03 +/- 9.29) pg/ml vs (54.69 +/- 12.39) pg/ml and (54.05 +/- 7.68) pg/ml, P < 0.05 and P < 0.01, respectively). Serum IL-6 in group 3 was also significantly higher than those in group 1 and group 2 ((70.09 +/- 14.53) pg/ml vs (56.43 +/- 10.11) pg/ml and (60.77 +/- 9.70) pg/ml, P < 0.01 and P < 0.05, respectively). Patients in group 3 had a thicker internal layer of vessels than in group 1 ((0.356 +/- 0.056) mm vs (0.111 +/- 0.021) mm, P < 0.01). Expression of CD68 and MCP-1 in the fistula vessel walls in group 3 were much higher than those in group 1 (P < 0.01). Moreover, serum hs-CRP level was positively correlated with the neointimal hyperplasia, the expression of CD68 and MCP-1 in fistula vessel (P < 0.01, respectively).</p><p><b>CONCLUSION</b>Microinflammation might be involved in the dysfunction of AVF in patients with maintenance hemodialysis.</p>

Epithelial to mesenchymal transition in the progression of tubulointerstitial fibrosis / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To review the mechanisms of epithelial to mesenchymal transition (EMT) and its role in the progression of tubulointerstitial fibrosis.</p><p><b>DATA SOURCES</b>The data used in this review were obtained mainly from the studies of EMT reported from 2000-2006.</p><p><b>STUDY SELECTION</b>Relevant articles on studies of EMT in tubulointerstitial fibrosis were selected. Data were mainly extracted from the 45 articles listed in the reference section of this review.</p><p><b>RESULTS</b>The process of EMT has gained wide recognition as candidate mechanism in progression of chronic fibrotic disorders. New markers were identified and facilitate the observation of EMT. EMT is regulated by many factors through activation of kinase-dependent signaling cascades. Recent findings suggest that EMT is a reversible process, which can be controlled by factors for their epithelial inducing activities.</p><p><b>CONCLUSION</b>Remarkable progresses of EMT research have been made recently. Preventing or reversing EMT is a promising strategy against renal fibrosis.</p>

Role of integrin-linked kinase in renal tubular epithelial-mesenchymal transition of mice with obstructive nephropathy / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the expression of integrin-linked kinase (ILK) in kidneys of mice with unilateral ureteral obstruction and its relevance with the epithelial-mesenchymal transition.</p><p><b>METHODS</b>Mice were randomly divided into two groups, sham operation (C, n = 20) and unilateral ureteral obstruction (UUO, n = 40). The animals were sacrificed at day 1, 3, 7 and 14 respectively after the surgery. Tubulointerstitial fibrosis (TIF) was graded according to Masson staining. The protein level of ILK was examined by Western blot. Tissue/cytological expression for ILK, alpha-SMA and E-cadherin were investigated by immunohistochemistry. The mRNA levels of ILK, alpha-SMA and E-cadherin were analyzed by quantitative real-time PCR.</p><p><b>RESULTS</b>In the control animals (group C), weak staining for ILK was detected mainly in the podocytes. Significant increase of staining for ILK in the experimental mice (UUO group) was detected from day 1 onward (t = 16.5, P < 0.01), reaching the peak at day 7. The protein expression of E-cadherin was continuously down-regulated from day 3 onward after surgery (t = 21.0, P < 0.01), while expression for alpha-SMA was up-regulated. From day 1 to day 7, the protein expression of ILK was positively correlated with alpha-SMA (R = 0.88, P < 0.01), but negatively correlated with E-cadherin (R = -0.87, P < 0.01). The mRNA expression of ILK and alpha-SMA analyzed by real-time PCR increased from postoperative day 1 and 3 respectively, but the mRNA expression of E-cadherin decreased from day 3 onward.</p><p><b>CONCLUSION</b>Increasing expression of ILK occurs in the early phase of UUO mouse and may play an important role in the process of TIF through mediating the epithelial-mesenchymal transition.</p>

Connective tissue growth factor is associated with the early renal hypertrophy in uninephrectomized diabetic rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Renal hypertrophy has been regarded as the early feature of diabetic nephropathy (DN), which may eventually lead to proteinuria and renal fibrosis. However, the exact mechanism of renal hypertrophy is still unclear. The aim of this study was to investigate the possible association of connective tissue growth factor (CTGF) with renal hypertrophy in uninephrectomized diabetic rats.</p><p><b>METHODS</b>Seventy-two Sprague-Dawley (SD) rats were randomly divided into two groups: control group (group C, n = 32) and diabetic nephropathy (group DN, n = 40). Each group was re-divided into 4 subgroups according to the experimental period. The rats were sacrificed at 1, 2, 4, and 8 weeks respectively after induction of diabetes. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ) after rats had received uninephrectomy. Blood glucose (BG), body weight (BW), 24-h urinary albumin excretion (24hUalb), kidney weight (KW), KW/BW, glomerular tuft area (AG), glomerular tuft volume (VG), proximal tubular area (AT) at each time point, the width of glomerular basement membrane (GBM) and tubular basement membrane (TBM) at week 8 were measured when the rats were sacrificed. Renal expression of CTGF and p27kip1 were detected by immunohistochemical staining. The relationship between CTGF expression and increasing of VG and AT was analyzed.</p><p><b>RESULTS</b>There was a significant increase of 24hUalb, KW, and KW/BW from week 1 onward in diabetic rats compared to those in group C (P < 0.05, respectively), diabetic rats also had a significant increase of AG, VG, and AT from week 1 onward. It was also shown that diabetic rats had a thickening of GBM [(245.7 +/- 103.0) nm vs (121.8 +/- 19.1) nm, P < 0.01] and TBM [(767.7 +/- 331.1) nm vs (293.0 +/- 110.5) nm, P < 0.01] at week 8. There was a weak expression for CTGF and p27kip1 in normal glomeruli and tubuli, while a significant increasing expression of CTGF and p27kip1 was found in glomeruli and tubuli in diabetic kidney from week 1 onward (P < 0.05, respectively), and the extent of CTGF expression was positively correlated with AG (r = 0.92, P < 0.05), VG (r = 0.86, P < 0.05), AT (r = 0.94, P < 0.01) and positively correlated with the expression of p27kip1 (r = 0.96, P < 0.01).</p><p><b>CONCLUSION</b>The expression of CTGF increases in diabetic rat kidney at the early stage, which might be an important mediator of renal hypertrophy through arresting cell cycling.</p>

Effect of irbesartan on angiotensin II-induced hypertrophy of human proximal tubular cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Intrarenal activation of the renin angiotensin system (RAS) plays an important role in mediating renal fibrosis. Both angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II (AngII) receptor antagonists have been shown to exert a protective role against diabetic and non-diabetic nephropathy. However, the exact mechanism of how blocking local RAS prevents renal fibrosis is unclear. The present study was to investigate the influence of a new AngII receptor antagonist, irbesartan (Irb), on AngII-induced hypertrophy in human proximal tubular cell line (HK-2).</p><p><b>METHODS</b>The cell line, HK-2, was grown in Dulbeccos's Modified Eagle's Medium containing 10% heat-inactivated fetal calf serum. After rested in serum-free medium for 24 hours, the effects of Irb on AngII (10(-7) mol/L)-induced [(3)H]-leucine incorporation, total protein content (measured by the Coomassie brilliant blue G250 method), and change in cell size (determined by scanning electron microscopy) were observed. The influence of Irb on the cell cycle was analyzed by fluorescence activated cell sorter (FACS) flow cytometry.</p><p><b>RESULTS</b>AngII induced cell hypertrophy in a time and dose dependent manner. Stimulation of cells with AngII for 48 hours resulted in a increase in [(3)H]-leucine incorporation [0 hour: (5584 +/- 1016) cpm/10(5) cells vs 48 hours: (10741 +/- 802) cpm/10(5) cells, P < 0.05], which was significantly attenuated by treatment with Irb. AngII significantly increased the total protein content in HK-2 cells [control: (0.169 +/- 0.011) mg/10(5) cells vs AngII group: (0.202 +/- 0.010) mg/10(5) cells, P < 0.05], which was also markedly inhibited by cotreatment with Irb (P < 0.01). Scanning electron microscopy showed that AngII induced an increase in average physical cell size, which was significantly inhibited by Irb [control: (11.92 +/- 1.62) microm; AngII group: (20.63 +/- 3.83) micro m; AngII + Irb group: (13.59 +/- 3.15) micro m; P < 0.01 vs control, respectively]. Furthermore, flow cytometry revealed that AngII arrested cells in the G(0)-G(1) phase, which was significantly reversed by treatment with Irb [G(0)-G(1) cells in AngII group: (76.09 +/- 1.82)%, in AngII + Irb group: (67.00 +/- 2.52)%, P < 0.05].</p><p><b>CONCLUSION</b>Irb can inhibit AngII-induced hypertrophy in HK-2 cells.</p>