Weisheng Peng

Role of Fosinopril and Valsartan on Klotho Gene Expression Induced by Angiotensin II in Rat Renal Tubular Epithelial Cells.

Background/Aims: Klotho gene, a new anti-aging gene, is mainly expressed in the kidney tubules. Several studies have found the relationship between klotho and emergence and development of renal diseases. This study set out to explore the role of fosinopril (Fos) and valsartan (Val) on klotho expression induced by angiotensin II (Ang II) in rat renal tubular epithelial cells (NRK-52E). Methods: NRK-52E cells were divided into five groups according to the treatment of Ang II, Fos and Val. Transforming growth factor-β1 (TGF-β1), p38, phospho-p38 (p-p38), p53, and Sp1 protein expression were determined by immunohistochemical and Western blotting analysis. Klotho expression was detected by reverse transcription-polymerase chain reaction and Western blotting analysis. Results: Ang II upregulated TGF-β1, p-p38 and p53 expression, and inhibited Sp1 and klotho expression in NRK-52E cells. After the intervention of Fos and/or Val, TGF-β1, p-p38 and p53 expression were downregulated, Sp1 and klotho expression were upregulated. TGF-β1 and p53, Sp1 and klotho expression exhibited a positive linear correlation, respectively. Conclusion: We conclude that Fos and Val have a protective role in Ang II-induced renal damage, and it may be through mechanism of inhibiting TGF-β1, p-p38 and p53 expression, thus upregulating Sp1 and klotho expression.

TAK-242, a Toll-Like Receptor 4 Antagonist, Protects against Aldosterone-Induced Cardiac and Renal Injury.

Cardiovascular and renal inflammation induced by Aldosterone (Aldo) plays an important role in the pathogenesis of hypertension and renal fibrosis. Toll-like receptor 4 (TLR4) signaling contributes to inflammatory cardiovascular and renal diseases, but its role in Aldo-induced hypertension and renal damage is not clear. In the current study, rats were treated with Aldo-salt combined with TAK-242 (a TLR4 signaling antagonist) for 4 weeks. Hemodynamic, cardiac and renal parameters were assayed at the indicated time. We found that Aldo-salt–treated rats present cardiac and renal hypertrophy and dysfunction. Cardiac and renal expression levels of TLR4 as well as levels of molecular markers attesting inflammation and fibrosis are increased by Aldo infusion, whereas the treatment of TAK-242 reverses these alterations. TAK-242 suppresses cardiac and renal inflammatory cytokines levels (TNF-a, IL-1β and MCP-1). Furthermore, TAK-242 inhibits hypertension, cardiac and renal fibrosis, and also attenuates the Aldo-induced Epithelial-Mesenchymal Transition (EMT). In experimental hyperaldosteronism, upregulation of TLR4 is correlated with cardiac and renal fibrosis and dysfunction, and a TLR4 signaling antagonist, TAK-242, can reverse these alterations. TAK-242 may be a therapeutic option for salt-sensitive hypertension and renal fibrosis.

Fosinopril and Losartan Regulate Klotho Gene and Nicotinamide Adenine Dinucleotide Phosphate Oxidase Expression in Kidneys of Spontaneously Hypertensive Rats

Background/Aims: Klotho, a newly identified antiaging gene, predominantly detected in the kidney, has pleiotropic protective effects on kidney diseases. Several studies have confirmed the association between Klotho and oxidative stress. The present studies were performed to explore effects of fosinopril (Fos) and losartan (Los) on Klotho and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase expression in kidneys of spontaneously hypertensive rats (SHR). Methods: Twenty-four male 22-week-old SHR were randomly divided into three groups: model group, Fos group and Los group. Wistar-Kyoto rats were taken as control. After 8 weeks, urinary N-acetyl-β-D-glucosaminidase (NAGase), 24 h urinary protein (Upro), serum creatinine (Scr), blood urea nitrogen (BUN) and renal pathological changes were detected. Renal mRNA and protein expression of Klotho and three subunits of NADPH oxidase protein expression were evaluated. Results: As compared to the model group, NAGase, Upro, Scr and BUN were decreased; the typical renal pathological damage was relieved in the Fos or Los group. Fos or Los inhibited the reduction of Klotho expression, and reduced the elevation of NADPH oxidase expression. Conclusion: Abnormal expression of Klotho and NADPH oxidase plays important roles in progression of hypertensive renal damage. Fos and Los can increase Klotho expression, and inhibit NADPH oxidase expression, which may be one of the mechanisms of their protective effects in hypertensive renal damage.

Spironolactone Rescues Dot1a-Af9-Mediated Repression of Endothelin-1 and Improves Kidney Injury in Streptozotocin-Induced Diabetic Rats

The molecular mechanism linking aldosterone and endothelin-1 in the development of diabetic nephropathy has not been completely elucidated. Here, we provide evidence showing that streptozotocin-induced diabetic rats have significantly increased aldosterone and endothelin-1 in the kidney tissue and markedly decreased expression of Dot1a and Af9. Blocking aldosterone with spironolactone significantly reduced proteinuria, glomerulosclerosis, tubulointerstitial injury and endothelin-1 expression, and significantly increased Dot1a and Af9 expression. Increasing Dot1a and Af9 expression by spironolactone or by stable transfection led to impaired endothelin-1 expression in NRK-52 cells. In contrast, downregulation of Dot1a and Af9 by aldosterone in NRK-52E cells caused upregulation of endothelin-1. Genetic inactivation of Dot1l, which encodes Dot1a, in Aqp2-expressing principal cells of mouse kidney impaired association of Dot1a and H3 dimethyl K79 with the specific subregions of endothelin-1 promoter, and upregulates endothelin-1 mRNA and protein expression. Our data suggest that Dot1a and Af9 repress endothelin-1 in vitro and in vivo. Excessive aldosterone induces kidney injury, in part possibly by downregulating Dot1a and Af9, and thus relieving Dot1a-Af9-mediated repression to increase endothelin-1 transcription. Spironolactone ameliorates kidney injury in Streptozotocin-induced diabetic rats, possibly by restoring Dot1a-Af9-mediated repression to reduce endothelin-1 expression. Therefore, Dot1a and Af9 as aldosterone-downregulated targets are negative regulators of endothelin-1 transcription in vitro and in vivo, and may be considered as new potential therapeutic targets of kidney injury in diabetes.

Hemolytic Streptococcus may exacerbate kidney damage in IgA nephropathy through CCL20 response to the effect of Th17 cells

Background The exacerbation of IgA nephropathy (IgAN) is related to respiratory tract infection with hemolytic streptococcus (HS), but the mechanism is unknown. In this study we investigated the role of chemokine ligand 20 (CCL20) in response to the effect of T helper 17 (Th17) cells in the pathogenesis of IgAN associated with HS. Methods Thirty mice were randomly divided into five groups: control mice (control), IgAN mice (IgAN), HS-infected IgAN mice (HS-IgAN), CCL20-treated IgAN mice (CCL20-IgAN), and CCL20-treated HS infected IgAN mice (CCL20-HS-IgAN). IgAN mice were induced with lipopolysaccharide, carbon tetrachloride and bovine serum albumin. Then the mice were sensitized with CCL20 antibody and infected with alpha-hemolytic streptococcus (α-HS) isolated from tonsils in sequence. Urine Albumin-Creatinine ratio and sediments were measured. The pathological changes in kidney and lung tissues were observed under microscopy. Th17 cells and regulatory T cells (Tregs) in kidneys were tested by flow cytometry. CCL20, IL-17A, IL-6 and IL-21 in the kidneys were detected by ELISA. Results The IgAN mice had albuminuria and microscopic hematuria, renal mesangial proliferation, IgA deposition, high electron dense deposition in glomerular mesangial region, decreased frequency of Tregs, increased frequency of Th17 and Th17-Treg ratio. Furthermore, Th17-related cytokines CCL20, IL-17A, IL-6 and IL-21 were all increased in the kidneys of IgAN mice. Compared with IgAN mice, the manifestations in HS-IgAN mice were more severe, but alleviated in CCL20-treated groups. Conclusion α-HS may exacerbate kidney damage in IgAN through CCL20 response to the effect of Th17 cells.

Smad7 gene transfer attenuates angiogenesis in peritoneal dialysis rats

Transforming growth factor‐β (TGF‐β) has been shown to play a role in peritoneal angiogenesis associated with peritoneal dialysis (PD). The present study investigated whether blockade of TGF‐β signalling with Smad7 has a therapeutic effect on PD induced‐peritoneal angiogenesis.

Inhibition of Rho-kinase alleviates peritoneal fibrosis and angiogenesis in a rat model of peritoneal dialysis

Abstract Background/Aims: The present study investigated whether Rho-kinase inhibition had a therapeutic role on the pathogenesis of peritoneal fibrosis and angiogenesis. Methods: A rat model of peritoneal dialysis was induced by a daily intraperitoneal infusion of 4.25% Dianeal. Those rats were treated with Rho-kinase inhibitor, fasudil. Immunofluorescence, Western blot and RT-PCR were used to detect the expression of TGF-β1, Collagen I, αSMA and VEGF in each group. Microvessel density (MVD) was measured by immunohistochemistry. Rho-kinase activity was determined by western immunoblotting. Results: Rho-kinase was activated in the peritoneum of the PD group, which was inhibited by fasudil. Compared with PD group, the mRNA and protein expressions of TGF-β1, αSMA and Collagen I were significantly downregulated in fasudil treatment groups in a dose-dependent manner, and the expression of VEGF and peritoneal MVD was also significantly downregulated in fasudil treatment groups in a dose-dependent manner. Conclusion: The Rho-kinase was activated in the peritoneum of the peritoneal dialysis rats, and the inhibition of Rho-kinase by fasudil can remarkably decrease peritoneal fibrosis and angiogenesis.

Fibroblast growth factor-23 and interleukin-6 are risk factors for left ventricular hypertrophy in peritoneal dialysis patients.

Background Left ventricular hypertrophy (LVH) is a major risk factor for cardiovascular death in dialysis patients. Fibroblast growth factor-23 (FGF-23) and interleukin-6 (IL-6) were thought to be related to cardiovascular diseases (CVDs) in dialysis. Methods To determine the relationship between FGF-23, IL-6 and LVH in continuous ambulatory peritoneal dialysis (CAPD) patients, serum FGF-23 and IL-6 levels as well as standard laboratory parameters were assessed in 62 CAPD patients and 30 healthy controls. LVH was determined by echocardiography in dialysis patients. Results Serum FGF-23 and IL-6 levels were significantly higher in CAPD patients than in healthy controls, whereas both were higher in patients with LVH than in patients without LVH. FGF-23 was found to be positively associated with left ventricle mass index (LVMI) and serum phosphate. IL-6 level was positively associated with LVMI and negatively correlated with serum albumin and hemoglobin. Serum FGF-23 level was positively correlated with IL-6 level. Conclusion FGF-23 and IL-6 are independent risk factors for LVH in CAPD patients and both collaborated in causing LVH in CAPD.

Intermittent low-dose digoxin may be effective and safe in patients with chronic heart failure undergoing maintenance hemodialysis

A low dose of digoxin is known to reduce mortality and hospitalization in patients with heart failure; however, the safety of digoxin in treating patients with heart failure on maintenance hemodialysis remains controversial. The objective of this study was to determine the effectiveness and safety of digoxin at lower doses in patients with heart failure on maintenance hemodialysis using a retrospective cohort study. This study included 67 heart-failure patients on maintenance hemodialysis: Twenty-four patients received intermittent low doses of digoxin (ILDD), 23 patients received continuous low doses of digoxin (CLDD) and the remaining patients were used as a control group without digoxin treatment. The brain natriuretic peptide (BNP) level and serum digoxin concentrations (SDCs) were measured by ELISA and the changes in left ventricular end diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF), cardiac output (CO) and heart rate (HR) were evaluated by two-dimensional echocardiography. The symptoms of digoxin toxicity were monitored in the treated patients. Compared with the control group, LVEDD, BNP and HR decreased significantly between days 0 and 60 in the ILDD and CLDD groups, but LVEF and CO increased between days 0 and 60 in the same groups (all P<0.05). The levels of BNP and the LVEDD, CO, LVEF and HR were not significantly different between the ILDD and CLDD groups (P>0.05). Furthermore, and the mean SDC of the ILDD group was lower than that of the CLDD group. In the ILDD group, no patients had apparent symptoms of toxicity, but four patients developed digoxin toxicity in the CLDD group. In conclusion an intermittent lower dose of digoxin has beneficial effects and clinical safety in hemodialysis patients with congestive heart failure.

SB-216763, a GSK-3ß inhibitor, protects against aldosterone-induced cardiac, and renal injury by activating autophagy.

Cardiovascular and renal inflammation induced by Aldosterone (Aldo) plays a pivotal role in the pathogenesis of hypertension and renal fibrosis. GSK‐3β contributes to inflammatory cardiovascular and renal diseases, but its role in Aldo‐induced hypertension, and renal damage is not clear. In the present study, rats were treated with Aldo combined with SB‐216763 (a GSK‐3β inhibitor) for 4 weeks. Hemodynamic, cardiac, and renal parameters were assayed at the indicated time. Here we found that rats treated with Aldo presented cardiac and renal hypertrophy and dysfunction. Cardiac and renal expression levels of molecular markers attesting inflammation and fibrosis were increased by Aldo infusion, whereas the treatment of SB‐216763 reversed these alterations. SB‐216763 suppressed cardiac and renal inflammatory cytokines levels (TNF‐a, IL‐1β, and MCP‐1). Meanwhile, SB‐216763 increased the protein levels of LC3‐II in the cardiorenal tissues as well as p62 degradation, indicating that SB‐216763 induced autophagy activation in cardiac, and renal tissues. Importantly, inhibition of autophagy by 3‐MA attenuated the role of SB‐216763 in inhibiting perivascular fibrosis, and tubulointerstitial injury. These data suggest that SB‐216763 protected against Aldo‐induced cardiac and renal injury by activating autophagy, and might be a therapeutic option for salt‐sensitive hypertension and renal fibrosis.