Resveratrol increases nephrin and podocin expression and alleviates renal damage in rats fed a high-fat diet

Oxidative Stress Contributes to Slit Diaphragm Defects Caused by Disruption of Endocytosis

Introduction

Podocyte slit diaphragms are an important component of the glomerular filtration barrier. Podocyte injury frequently includes defects in slit diaphragms, and various mechanisms for these defects have been described, including altered endocytic trafficking of slit diaphragm proteins or oxidative stress. However, the potential relationship between endocytosis and oxidative stress in the context of slit diaphragm integrity has not been extensively considered.

Methods

To examine the potential relationships between endocytosis, oxidative stress, and slit diaphragm integrity, we induced genetic or pharmacological disruption of endocytosis in Drosophila nephrocytes (the insect orthologue of podocytes) and cultured human podocytes. We then employed immunofluorescence microscopy to analyze protein localization and levels, and to quantify signal from reactive oxygen species (ROS) dyes. Immunoprecipitation from podocyte cell lysates was used to examine effects on slit diaphragm protein complex formation (i.e., nephrin/podocin and nephrin/ZO-1).

Results

Disruption of endocytosis in nephrocytes and podocytes led to slit diaphragm defects, elevated levels of ROS (oxidative stress), and activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway. In nephrocytes with defective endocytosis, perturbation of Nrf2 signaling exacerbated slit diaphragm defects. Conversely, overexpression of Nrf2 target genes catalase or glucose-6-phosphate dehydrogenase (G6PD) significantly ameliorated slit diaphragm defects caused by disruption of endocytosis.

Conclusion

Oxidative stress is an important consequence of defective endocytosis and contributes to the defects in slit diaphragm integrity associated with disruption of endocytic trafficking.

Monkfish (Lophius litulon) Peptides Ameliorate High-Fat-Diet-Induced Nephrotoxicity by Reducing Oxidative Stress and Inflammation via Regulation of Intestinal Flora

BACKGROUND

Renal damage and intestinal flora imbalance due to lipotoxicity are particularly significant in terms of oxidative stress and inflammation, which can be alleviated with bioactive peptides. The monkfish (Lophius litulon) is rich in proteins, which can be used as a source of quality bioactive peptides. This study aimed to examine the protective effect of monkfish peptides on renal injury and their potential role in regulating gut microbiota.

METHODS

Monkfish meat was hydrolyzed using neutral protease and filtered, and the component with the highest elimination rate of 2,2-diphenyl-1-picrylhydrazyl was named lophius litulon peptides (LPs). Lipid nephrotoxicity was induced via high-fat diet (HFD) feeding for 8 weeks and then treated with LPs. Oxidative stress, inflammatory factors, and intestinal flora were evaluated.

RESULTS

LP (200 mg/kg) therapy reduced serum creatinine, uric acid, and blood urea nitrogen levels by 49.5%, 31.6%, and 31.6%, respectively. Renal vesicles and tubules were considerably improved with this treatment. Moreover, the activities of superoxide dismutase, glutathione peroxidase, and total antioxidant capacity increased significantly by 198.7%, 167.9%, 61.5%, and 89.4%, respectively. LPs attenuated the upregulation of HFD-induced Toll-like receptor 4 and phospho-nuclear factor-kappa B and increased the protein levels of heme oxygenase 1, nicotinamide quinone oxidoreductase 1, and nuclear factor erythroid 2-related factor 2. The dysbiosis of intestinal microbiota improved after LP treatment.

CONCLUSIONS

LPs significantly improve antioxidant activity, reduce inflammatory cytokine levels, and regulate intestinal dysbiosis. Thus, LPs are potential compounds that can alleviate HFD-induced renal lipotoxicity.

Effect of vitamin D analogues calcitriol and paricalcitol in a rat model of puromycin aminonucleoside-induced nephrotic syndrome

Background Renoprotective effects of vitamin D analogues have been shown in several experimental and clinical studies, the exact mechanism of the therapeutic effectiveness of these analogues in Nephrotic syndrome remains unclear, and these are relatively few studies on potential treatment roles for vitamin D analogues in nephrotic-range proteinuria. ?ndicate similar efficacy of the vitamin D analogues calcitriol and paricalcitol in time-limited amelioration of proteinuria in nephrotic syndrome, yet suggest the likelihood of mechanisms other than direct upregulation of nephrin and podocin in podocytes underlie the renoprotective effects of vitamin D analogues. Objective To investigate the effect of vitamin D (Vit D) analogues calcitriol and paricalcitol on urinary protein/creatinine ratio (UPCR) and renal podocin and nephrin expression in a rat model of puromycin aminonucleoside (PAN)-induced nephrotic syndrome (NS). Methods A total of 28 male Wistar Albino rats were separated into 4 groups (n=7 for each) including CON [control; intraperitoneal (IP) saline injection], PAN (NS + IP saline injection), PAN-C (NS + IP 0.4 µg/kg/day calcitriol injection), and PAN-P (NS + IP 240 ng/kg/day paricalcitol injection). Nephrotic syndrome was induced via intravenous (IV) administration of 10mg/100gr PAN. The UPCR as well as histopathological, immuno-histochemical, and real time PCR analyses of kidney tissue specimens were recorded and analyzed among the 4 groups. Results Median UPCR (Day 4) was significantly lower in both the PAN-C [1.45 (range 1.20-1.80)] and PAN-P [1.40 (range 1.10-1.80)] groups than in the PAN group [2.15 (range 2.00-2.40)] (P<0.01 for each). The PAN group had significantly higher mean UPCR than the CON group [1.75 (range 1.40-2.00); P<0.05].  No significant difference in UPCR was noted between groups on Day 7. Median podocin mRNA expression was significantly higher in the PAN-P group compared to the PAN group [22.55 (range 22.42-23.02) vs. 22.06 (range 21.81-22.06), respectively; (P<0.01)]. Conclusion Seven-day calcitriol and paricalcitol supplementation in a rat model of PAN-induced nephrotic syndrome had similar efficacy, in terms of temporary amelioration of proteinuria.

Urolithins Modulate the Viability, Autophagy, Apoptosis, and Nephrin Turnover in Podocytes Exposed to High Glucose

Urolithins are bioactive compounds generated in human and animal intestines because of the bacterial metabolism of dietary ellagitannins (and their constituent, ellagic acid). Due to their multidirectional effects, including anti-inflammatory, antioxidant, anti-cancer, neuroprotective, and antiglycative properties, urolithins are potential novel therapeutic agents. In this study, while considering the future possibility of using urolithins to improve podocyte function in diabetes, we assessed the results of exposing mouse podocytes cultured in normal (NG, 5.5 mM) and high (HG, 25 mM) glucose concentrations to urolithin A (UA) and urolithin B (UB). Podocytes metabolized UA to form glucuronides in a time-dependent manner; however, in HG conditions, the metabolism was lower than in NG conditions. In HG milieu, UA improved podocyte viability more efficiently than UB and reduced the reactive oxygen species level. Both types of urolithins showed cytotoxic activity at high (100 µM) concentration. The UA upregulated total and surface nephrin expression, which was paralleled by enhanced nephrin internalization. Regulation of nephrin turnover was independent of ambient glucose concentration. We conclude that UA affects podocytes in different metabolic and functional aspects. With respect to its pro-survival effects in HG-induced toxicity, UA could be considered as a potent therapeutic candidate against diabetic podocytopathy.

Effects of semaglutide on vascular structure and proteomics in high-fat diet-induced obese mice

BACKGROUND

Obesity is a chronic metabolic disease caused by a combination of genetic and environmental factors. To determine whether semaglutide could improve aortic injury in obese C57BL/6J mice, and further explore its molecular mechanism of action using proteomics.

METHODS

24 C57BL/6J male mice were randomly divided into normal diet group (NCD group), high-fat diet group (HFD group) and high-fat diet + semaglutide group (Sema group, semaglutide (30 nmol/kg/d) for 12 weeks). The serum samples were collected from mice to detect blood glucose, insulin and blood lipid concentrations. Aortic stiffness was detected by Doppler pulse wave velocity (PWV). Changes in vascular structure were detected by HE, masson, EVG staining and electron microscopy. The aorta-related protein expression profiles were detected by proteomic techniques, and proteins with potential molecular mechanisms were identified.

RESULTS

Semaglutide could reduce body weight, the concentrations of blood glucose, total cholesterol (TC), triglycerides (TG), lipoprotein cholesterol (LDL-C), and reduce the aortic PWV and ameliorate vascular damage in obese mice. The results of proteomic analysis showed there were 537 up-regulated differentially expressed proteins (DEPs) and 322 down-regulated DEPs in NCD/HFD group, 251 up-regulated DEPs and 237 down-regulated proteins in HFD/Sema group. There were a total of 25 meaningful overlapping DEPs in the NCD/HFD and HFD/Sema groups. GO enrichment analysis of overlapping DEPs found that these differential proteins were mainly located in the signaling pathways of the extracellular matrix. The most obvious changes of extracellular matrix associated proteins in the three experimental groups were Coll5a1, Lama4, Sparc.

CONCLUSION

Semaglutide may protect vascular structure and improve endothelial permeability by reducing the levels of Coll5a1, Lama4, Sparc in extracellular matrix, so as to improve vascular function and achieve vascular protection.

High-fat diet caused renal damage in ApoE-/- mice via the activation of RAGE-mediated inflammation

High-fat diet (HFD) is the primary cause of metabolic syndrome associated chronic kidney disease. This study aimed to investigate the pathogenesis of HFD-induced kidney injury. ApoE^-/- mice were fed with HFD and kidney damage was examined. In addition, HK-2 human renal proximal tubular epithelial cells were treated with fructose and receptor of advanced glycation end products (RAGE) siRNA. The results showed that HFD increased body weight, blood glucose and insulin resistance in ApoE^-/- mice. The kidney damage was associated with increased oxidative stress and strong staining of RAGE and NF-κB in kidney tissues, as well as high serum levels of TNF-α, IL-1β and IL-6. Western-blot analysis showed that HFD increased the levels of RAGE, p-IκBα, p-NF-κB, bax, caspase-3 and caspase-9 but decreased the levels of Bcl-2 in kidney tissues. In HK-2 cells, fructose promoted the secretion of TNF-α, IL-1β and IL-6 and increased the levels of RAGE, p-IκBα, p-NF-κB, bax, caspase-3 and caspase-9, but decreased the levels of Bcl-2. Moreover, RAGE siRNA could attenuate increased levels of p-IκBα, p-NF-κB, bax, caspase-3 and caspase-9 while restore decreased levels of Bcl-2 in fructose-treated HK-2 cells. In conclusion, HFD causes kidney injury by promoting oxidative stress, inflammation and apoptosis possibly through the activation of RAGE/NF-κB pathway.

Anthocyanin-rich fraction from black rice, Oryza sativa L. var. indica "Luem Pua," bran extract attenuates kidney injury induced by high-fat diet involving oxidative stress and apoptosis in obese rats

Obesity is acknowledged as being a world health problem and increases the risk of several chronic diseases including chronic kidney disease. High-fat diet consumption and obesity-related renal disease show a close correlation with increased oxidative stress. Black rice bran extract, (BRE) Oryza sativa L. variety "Luem Pua" contains a high anthocyanin content. This study evaluated the effects of an anthocyanin-rich fraction from BRE on renal function and oxidative stress in obese rats. Male Wistar rats were fed a normal diet (ND) or high-fat diet (HF) for 16 weeks. After this, the rats were given either vehicle (HF), BRE 100 (HF100) or BRE 200 mg/kg/day (HF200) orally for 8 weeks. The HF rats had increased body weight, visceral fat weight, plasma glucose, cholesterol and triglycerides. These parameters were normalized following HF100 administration and showed a decreasing trend with HF200. Serum creatinine and renal cortical MDA were increased in the HF group but these effects were attenuated by BRE. Negative kidney injury and histopathology changes were observed following a HF, but treatment with BRE reversed these deleterious effects. These results suggest that BRE could be used as a food supplement to improve metabolic disturbance and prevent kidney dysfunction in cases of obesity.

Effect of resveratrol intervention on renal pathological injury and spermatogenesis in type 2 diabetic mice

BACKGROUND

Type 2 diabetes (T2D) is a clinically common cardiovascular disease that can lead to kidney damage and adversely affect male fertility and sperm quality. Resveratrol (Res) is a natural product that has a wide range of effects in animals and cell models.

OBJECTIVE

This research is designed to observe the effect of resveratrol (Res) intervention on renal pathologic injury and spermatogenesis in mice with type 2 diabetes (T2D).

METHODS

Sixty healthy male SD mice without specific pathogens (SPF grade) were selected, and numbered by statistical software to randomize into control group (CG; n=20), model group (MG; n=20) and research group (RG; n=20). Mice in CG were given regular diet, while those in MG and RG were fed with high fat diet. Subsequently, RG was given Res intervention while MG received no treatment. Biochemical indexes [triglyceride (TG), total cholesterol (TC), fasting blood glucose (FBG), 24-hour urinary albumin excretion rate (24h-UAER)] of mice in the three groups before and after intervention were observed and recorded. The effect of Res on oxidative stress, kidney histopathological structure, spermatogenic function, sperm density and viability of mice, as well as spermatogenic cell cycle of testis were determined.

RESULTS

Res reduced hyperlipidemia and hyperglycemia in T2D mice. By reducing malondialdehyde (MDA) and increasing superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), Res relieved oxidative stress and alleviated kidney tissue damage. In addition, Res improved the spermatogenic function of T2D mice by increasing the sperm density and survival rate and restoring the percentage of spermatogenic cells at all levels.

CONCLUSIONS

Res intervention in T2D mice can reduce kidney tissue damage, lower blood glucose (BG), and improve spermatogenic function by increasing sperm density and restoring the percentage of spermatogenic cells at all levels.

Hypoglycemic effects and mechanism of different molecular weights of konjac glucomannans in type 2 diabetic rats

Konjac glucomannan (KGM) is a hypoglycemic polysaccharide with a wide range of molecular weights. But study on hypoglycemic effects of KGMs relate to molecular weight is limited. In this study, KGMs with high and medium molecular weights, and the degraded KGMs were analyzed with physicochemical properties, hypoglycemic effects and mechanisms. Results showed that as the molecular weight KGMs decreased, the viscosity decreased, molecular flexibility increased, while chemical groups, crystal structures and main chains showed little change. KGMs with medium molecular weights (KGM-M1, KGM-M2) showed better effects on increasing body weight, decreasing levels of fasting blood glucose, insulin resistance, total cholesterol and low density lipoprotein cholesterol, and enhancing integrity of pancreas and colon, than KGMs with high or low molecular weights (KGM-H, KGM-L) in type 2 diabetic rats. Mechanism analysis suggested that KGM-M1 and KGM-M2 had higher antioxidant and anti-inflammatory activities on elevating superoxide dismutase, decreasing malondialdehyde and tumor necrosis factor-α levels. Moreover, KGM-M1 and KGM-M2 increased gut microbiota diversity, Bacteroidetes/Firmicutes ratio and Muribaculaceae, decreased Romboutsia and Klebsiella, and improved 6 diabetic related metabolites. Combined, KGM-M1 and KGM-M2 showed higher hypoglycemic effects, due to regulatory activities of antioxidant, anti-inflammatory, intestinal microbiota, and relieved metabolic disorders.

Nobiletin ameliorates high-fat diet-induced vascular and renal changes by reducing inflammation with modulating AdipoR1 and TGF-β1 expression in rats

AIMS

We investigate the effect of nobiletin on vascular and renal alterations and possible mechanisms involved in high-fat diet (HFD)-fed rats.

MAIN METHODS

Male Sprague-Dawley rats were fed a HFD with fructose 15% in drinking water for 16 weeks. HFD-fed rats were treated with nobiletin (20 or 40 mg/kg/day) or vehicle for the last 4 weeks.

KEY FINDINGS

HFD-fed rats treated with nobiletin was significantly reduced obesity, hypertension, dyslipidemia and hyperinsulinemia. Nobiletin improved vascular endothelial function, restored creatinine clearance, and reduced plasma urea and creatinine levels, as well as urinary protein excretion. Nobiletin markedly alleviated vascular medial cross-sectional area (CSA) and collagen deposition, glomerular extracellular matrix (ECM) accumulation, and renal fibrosis. Nobiletin significantly elevated plasma adiponectin levels, together with upregulated adiponectin receptor 1 (AdipoR1) and suppressed transforming growth factor-β1 (TGF-β1) expression in kidney. In addition, an increase of plasma tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) was significantly attenuated after nobiletin treatment.

SIGNIFICANCE

Our results suggest that nobiletin attenuates HFD-induced vascular and renal alterations in rats, which is possibly related to the modulation of AdipoR1 and TGF-β1expression, and suppression of inflammation.

Effects of resveratrol on the inflammatory response and renal injury in hyperuricemic rats

BACKGROUND/OBJECTIVES

Hyperuricemic nephropathy is a common cause of acute kidney injury. Resveratrol can ameliorate kidney injury, but the explicit mechanism remains unclear. We investigated the effects of resveratrol on the inflammatory response and renal injury in hyperuricemic rats.

MATERIALS/METHODS

A rat model of hyperuricemic nephropathy was established by the oral administration of a mixture of adenine and potassium oxinate. Biochemical analysis and hematoxylin and eosin staining were performed to assess the rat kidney function. Enzyme-linked immunosorbent assays were performed to evaluate the immune and oxidative responses.

RESULTS

The expression levels of urine albumin and β2-microglobulin were significantly decreased after resveratrol treatment. In addition, the levels of serum creatinine and uric acid were significantly decreased in the resveratrol groups, compared with the control group. The levels of proinflammatory factors, such as interleukin-1β and tumor necrosis factor-α, in kidney tissue and serum were also increased in the hyperuricemic rats, and resveratrol treatment inhibited their expression. Moreover, the total antioxidant capacity in kidney tissue as well as the superoxide dismutase and xanthine oxidase levels in serum were all decreased by resveratrol treatment.

CONCLUSIONS

Resveratrol may protect against hyperuricemic nephropathy through regulating the inflammatory response.

SIRT1-mediated amelioration of oxidative stress in kidney of alcohol-aflatoxin-B1-induced hepatocellular carcinoma by resveratrol is catalase dependent and GPx independent

Hepatocellular carcinoma (HCC) is a type of primary liver cancer and dietary exposure to aflatoxins is a major risk factor of HCC. The current study aimed to assess the role of resveratrol and nicotinamide in renal toxicity during alcohol-aflatoxin-B1-induced HCC. The results revealed that resveratrol treatment normalized the level of urea, lipid peroxidation, lactate and lactate dehydrogenase, which were increased in HCC. It also downregulated the increased expression of sirtuin 1 in HCC kidney. Furthermore, amelioration of oxidative stress in kidney of HCC rats by resveratrol was observed to be catalase dependent and glutathione peroxidase independent.

Atorvastatin attenuates obese-induced kidney injury and impaired renal organic anion transporter 3 function through inhibition of oxidative stress and inflammation

An excessive consumption of high-fat diet can lead to the alterations of glucose and lipid metabolism, impaired insulin signaling and increased ectopic lipid accumulation resulting in renal lipotoxicity and subsequent renal dysfunction. Atorvastatin is a lipid-lowering drug in clinical treatment. Several studies have reported that atorvastatin has several significant pleiotropic effects including anti-inflammatory, antioxidant, and anti-apoptotic effects. However, the effects of atorvastatin on metabolic disturbance and renal lipotoxicity in obesity are not fully understood. In this study, obesity in rat was developed by high-fat diet (HFD) feeding for 16 weeks. After that, the HFD-fed rats were received either a vehicle (HF), atorvastatin (HFA) or vildagliptin (HFVIL), by oral gavage for 4 weeks. We found that HF rats showed insulin resistance, visceral fat expansion and renal lipid accumulation. Impaired renal function and renal organic anion transporter 3 (Oat3) function and expression were also observed in HF rats. The marked increases in MDA level, renal injury and NF-κB, TGF-β, NOX-4, PKC-α expression were demonstrated in HF rats. Atorvastatin or vildagliptin treatment attenuated insulin resistance and renal lipid accumulation-induced lipotoxicity in HFA and HFVIL rats. Moreover, the proteins involved in renal inflammation, fibrosis, oxidative stress and apoptosis were attenuated leading to improved renal Oat3 function and renal function in the treated groups. Interestingly, atorvastatin showed higher efficacy than vildagliptin in improving insulin resistance, renal lipid accumulation and in exerting renoprotective effects in obesity-induced renal injury and impaired renal Oat3 function.

Resveratrol Protects Against Renal Damage via Attenuation of Inflammation and Oxidative Stress in High-Fat-Diet-Induced Obese Mice

Oxidative stress and inflammation play an important role in the chronic kidney disease associated with obesity. Resveratrol (RSV) has been reported to exhibit a wide range of biological activities including antioxidant and anti-inflammatory properties. The objective of the present study was to investigate the effects of RSV on renal inflammation and oxidative stress in obese mice induced by high-fat diet. Male C57BL/6 mice were induced to have nephropathy associated obesity by high-fat diet for 12 weeks. After 8 weeks of feeding, oral supplementation with 100 mg RSV/kg body weight/day was applied with the high-fat-diet feeding for another 4 weeks. The results showed that RSV treatment protected against renal damage induced by high-fat diet, as evidenced by the decreased serum creatinine and urea nitrogen levels, alleviation of glomerular damage, and tubular vacuolization. In addition, RSV enhanced the antioxidant enzyme activity; improved the expression of genes related to inflammation; and decreased the malondialdehyde, tumor necrosis factor-α, and interleukin-6 concentrations in the kidney of high-fat-diet mice. In conclusion, RSV could alleviate renal damage in obese mice induced by high-fat diet via suppressing inflammation and oxidative stress.

High-fat diets provoke phosphorus absorption from the small intestine in rats

OBJECTIVE

The ratio of dietary carbohydrate to fat may affect phosphorus metabolism because both calcium and phosphorus are regulated by similar metabolic mechanisms, and a high-fat diet (HFD) induces deleterious effects on the absorption of dietary calcium. We hypothesized that an HFD induces an increase in phosphorus absorption. The aim of this study was to evaluate the effects of differences in the quantity and quality of dietary fat on phosphorus metabolism over the short- and long-term.

METHODS

Eighteen 8-wk-old Sprague-Dawley male rats were fed an isocaloric diet containing varied ratios of carbohydrates to fat energy and sources of fat (control diet, HFD, and high- saturated fat diet [HF-SFA]). At 3 d and 7 wk after the allocation and initiation of the test diets, feces and urine were collected and used for phosphorus and calcium measurement.

RESULTS

The fecal phosphorous concentration (F-Pi) was lower in the HF-SFA group than in the other two groups; however, the urine phosphorus concentration (U-Pi) was significantly higher in the HF-SFA group than the other two groups when the rats were fed over the short- (P < 0.01) and long -term (P < 0.01 versus control, P < 0.05 versus HFD group). There were no significant differences in type-IIa sodium-phosphate cotransporter (NaPi-2 a) and type-IIc sodium-phosphate cotransporter (NaPi-2 c) mRNA expression, which are renal phosphate transport-related genes; however, the expression of type-IIb sodium-phosphate cotransporter (NaPi-2 b) and type-III sodium-phosphate cotransporter (Pit-1) mRNA in the duodenum was higher in the HFD and HF-SFA groups than in the control group (P < 0.05), although there were no significant differences in these in the jejunum.

CONCLUSIONS

The present results indicated that an HFD, particularly HF-SFA, increases intestinal phosphate absorption compared with control.

Resveratrol alleviates obesity-associated podocyte injury in ovariectomized obese rats

Obesity-associated podocyte injury increases in parallel with inflammatory responses. Resveratrol, as an anti-inflammatory and antioxidative agent, has been proven to be effective in obesity. The purpose of the present study was to investigate the function of resveratrol in the early stages of podocyte injury in ovariectomized rats fed a high-fat diet (HFD). The 3-month-old female Wistar rats were randomly divided into four groups: Sham operation with a standard diet; sham operation with a HFD; ovariectomy with a HFD (O+H); and ovariectomy plus HFD treatment with resveratrol (40 mg/kg/day) (O+H+R). Following 12 weeks, the weights of the rats were measured and serum was obtained to measure the levels of 17β-estradiol (E2), serum lipids, serum creatinine, fasting blood glucose (FBG) and insulin. Periodic acid-schiff staining was used to detect renal pathological changes. Meanwhile, the expression of the podocyte-associated proteins nephrin and Wilms' tumor-1 was investigated using immunohistochemical staining, and the levels of tumor necrosis factor-α, interleukin-6 and monocyte chemotactic protein-1 in renal tissues were determined using western blotting. Compared with the O+H group, resveratrol significantly reduced the body weight, serum levels of total cholesterol, low-density lipoprotein cholesterol, FBG and insulin resistance, and increased the levels of E2 in obese rats with an ovariectomy combined with an HFD (P<0.05). Compared with the O+H group, although the O+H+R group had no significant changes in renal pathology, the changes in the levels of podocyte-associated proteins and inflammatory markers were significantly reversed (P<0.05). These results suggest that resveratrol may attenuate early podocyte injury by improving lipid metabolism and insulin sensitivity, and subsequently inhibiting inflammatory responses in obese rats induced by an ovariectomy with a HFD.

Omega-3 attenuates high fat diet-induced kidney injury of female rats and renal programming of their offsprings

Context: Maternal diet composition could influence fetal organogenesis. Objective: We investigated effects of high fat diet (HFD) intake alone or combined with omega 3 during pregnancy, lactation and early days of weaning on nephrogenesis of pups and maternal renal function and morphology. Material and methods: Mothers and their pups included in each group were supplied with the same diet composition. Rats were divided into group I, II and III supplied with chow of either 10 kcal%, 45 kcal% or 45 kcal% from fat together with omega-3 respectively. Results: Group II showed increased serum urea and creatinine, renal TNF-α, IL1β. Structural injury was observed in mothers and their pups as Bowman's capsule and tubular dilatation and increased expression of PCNA that were decreased following omega-3 supplementation added to down regulation of Wnt4, Pax2 gene and podocin expression. Discussion and conclusion: Omega-3 supplementation improves lipid nephrotoxicity observed in mothers and their pups.

Protective effects of liraglutide on glomerular podocytes in obese mice by inhibiting the inflammatory factor TNF-α-mediated NF-κB and MAPK pathway

OBJECTIVE

To evaluate the protective effects of Glucagon-like peptide-1(GLP-1) receptor agonist (liraglutide) on glomerular podocytes of obese mice, and explore the possible underlying mechanism.

METHODS

Twelve of the thirty-four healthy and clean male mice were randomly selected as the normal control group. The remaining twenty-two mice were included in the high-fat diet (HFD) feeding group. After twelve weeks of high-fat diet and normal diet, two mice each from the HFD feeding group and the normal control group were randomly selected and sacrificed to suggested that the modeling was successful in the HFD feeding group. Then, twenty mice were randomly divided into HFD + liraglutide group (liraglutide group, n = 10) and HFD group (n = 10). The morphology and the structure of glomerular podocytes were observed using electron microscopy. Podocyte foot process diameter, glomerular basement membrane thickness were measured. ELISA was performed to determine the serum tumor necrosis factor α (TNF-α) level. The expression levels of TNF-α protein and nuclear factor-kappa B (NF-κB) in kidney tissues, extracellularsignal regulating kinase(ERK), c-Jun N-terminal kinase (JNK) and p38MAPK in the mitogenactivated protein kinases(MAPK) pathway were detected by western blotting.

RESULTS

HFD-feeding caused significant renal injury, podocyte pathological changes, podocyte foot process diameter and glomerular basement membrane thickness were significantly increased compared with the control group. Liraglutide injection significantly alleviated HFD-induced effects on renal functions and podocyte morphology, as 24 h urine protein, urinary albumin and podocyte histomorphology. Moreover, HFD-induced Inflammatory reaction were obviously attenuated by Liraglutide administration, so did the HFD-induced activation of TNF-α-mediated NF-κB and MAPK pathways.

CONCLUSION

Liraglutide reduced urinary albumin excretion in obesity-related glomerulopathy model mice, and improved podocyte morphology and structural damage. The mechanism may be partly related to the inhibition of TNF-α-mediated NF-κB and MAPK pathways.

Combined effects of DDE and hyperlipidic diet on metallothionein expression and synthesis in rat tissues

Metallothionein is well known for its detoxificant and anti-oxidant properties and has been shown to be effective to prevent hydroxyl radical-generated DNA degradation. The purpose of this investigation was to analyze the combined effect of two factors promoting cellular oxidative-stress, that is, the administration of the pesticide dichloro-diphenyl-dichloroethylene (DDE) and a high fat diet, on metallothionein expression and synthesis in rat liver and kidney. DDE is the main metabolite of dichloro-diphenyl-trichloroethane (DDT), and is commonly found in the food chain and in all tissues of living organisms, carried by the fats. Male Wistar rats were fed with a standard (N) or a high fat (HF) diet and exposed to DDE (10 mg/kg body mass, N + DDE and HF + DDE groups) or vehicle (corn oil, N, and HF groups) via gavage every day for 28 days. Tissues histology was determined by light microscopy analysis; differences in metallothionein gene expression and synthesis by real-time PCR and western blot, respectively. Finally, protein cellular localization was established by immunocytochemistry. The results showed a different involvement of metallothionein in defending tissues from HF- and DDE-induced oxidative stress, suggesting that hepatic and renal cells use different strategies against pro-oxidant species. In both cell types a marked increase in the metallothionein content was observed in the nucleus, with a concomitant drop of the cytoplasmatic protein, either under HF- and DDE-stress conditions; however, no synergistic or additive effects were observed between the action of fats and pesticide. These findings reinforce the role of metallothionein in protecting DNA from oxidative damage.

The therapeutic effects of resveratrol on hepatic steatosis in high-fat diet-induced obese mice by improving oxidative stress, inflammation and lipid-related gene transcriptional expression

So far, the majority of the previous animal studies have focused on the preventive effects of resveratrol (RSV) on non-alcoholic fatty liver disease (NAFLD) rather than the therapeutic effects. In this study, the therapeutic effects of RSV on hepatic oxidative stress (OS), inflammation, and lipid metabolism-related gene expression of obese mice induced by a high-fat diet (HFD) were investigated. Male C57BL/6 mice were fed a HFD for 8 weeks to induce obesity-related NAFLD model. And then, NAFLD mice were treated with daily RSV oral gavage at the dose of 100 mg/kg body weight for an additional 4 weeks. HFD-induced the elevation of serum total cholesterol, high-density lipoprotein cholesterol, glucose, insulin, aspartate aminotransferase and alanine aminotransferase levels, and homeostasis model assessment of insulin resistance, hepatic histology changes, the increases in hepatic triglyceride, malondialdehyde and tumor necrosis factor alpha concentrations, as well as the higher mRNA expression of hepatic toll-like receptor 4 and cluster of differentiation 36 in mice, were restored by RSV. The therapeutic effects of RSV against hepatic steatosis of HFD obese mice were attributed to the reduction of OS, inflammation and free fatty acid uptake.

Impact of obesity as an independent risk factor for the development of renal injury: implications from rat models of obesity

Diabetes and hypertension are the major causes of chronic kidney disease (CKD). Epidemiological studies within the last few decades have revealed that obesity-associated renal disease is an emerging epidemic and that the increasing prevalence of obesity parallels the increased rate of CKD. This has led to the inclusion of obesity as an independent risk factor for CKD. A major complication when studying the relationship between obesity and renal injury is that cardiovascular and metabolic disorders that may result from obesity including hyperglycemia, hypertension, and dyslipidemia, or the cluster of these disorders [defined as the metabolic syndrome, (MetS)] also contribute to the development and progression of renal disease. The associations between hyperglycemia and hypertension with renal disease have been reported extensively in patients suffering from obesity. Currently, there are several obese rodent models (high-fat diet-induced obesity and leptin signaling dysfunction) that exhibit characteristics of MetS. However, the available obese rodent models currently have not been used to investigate the impact of obesity alone on the development of renal injury before hypertension and/or hyperglycemia. Therefore, the aim of this review is to describe the incidence and severity of renal disease in these rodent models of obesity and determine which models are suitable to study the independent effects obesity on the development and progression of renal disease.

Renal outcomes with sodium glucose cotransporter 2 (SGLT2) inhibitor, dapagliflozin, in obese insulin-resistant model

A growing body of evidence indicates that obesity and insulin resistance contribute to the progression of renal disease. This study was performed to determine the effects of dapagliflozin, a novel sodium glucose cotransporter 2 (SGLT2) inhibitor, on renal and renal organic anion transporter 3 (Oat3) functions in high-fat diet fed rats, a model of obese insulin-resistance. Twenty-four male Wistar rats were divided into two groups, and received either a normal diet (ND) (n = 6) or a high-fat diet (HFD) (n = 18) for 16 weeks. At week 17, the HFD-fed rats were subdivided into three subgroups (n = 6/subgroup) and received either a vehicle (HFD), dapagliflozin (HFDAP; 1.0 mg/kg/day) or metformin (HFMET; 30 mg/kg/day), by oral gavage for four weeks. Metabolic parameters, renal function, renal Oat3 function, renal oxidative stress, and renal morphology were determined. The results showed that obese insulin-resistant rats induced by HFD feeding had impaired renal function and renal Oat3 function together with increased renal oxidative injury. Dapagliflozin or metformin treatment decreased insulin resistance, hypercholesterolemia, creatinine clearance and renal oxidative stress leading to improved renal function. However, dapagliflozin treatment decreased blood pressure, serum creatinine, urinary microalbumin and increased glucose excretions, and showed a greater ability to ameliorate impaired renal insulin signaling and glomerular barrier damage than metformin. These data suggest that dapagliflozin had greater efficacy than metformin for attenuating renal dysfunction and improving renal Oat3 function, at least in part by reducing renal oxidative stress and modulating renal insulin signaling pathways, and hence ameliorating renal injury.

Lipoxin A4 may attenuate the progression of obesity-related glomerulopathy by inhibiting NF-κB and ERK/p38 MAPK-dependent inflammation

OBJECTIVES

To investigate the effects of lipoxin A4 (LXA4) on inflammatory responses in obesity-related glomerulopathy (ORG) mouse model and its potential mechanisms.

METHODS

Male C57BL/6 mice were randomly divided into 4 groups: normal, model, LXA4, and LXA4/Boc-2 groups (n = 8). Mice in LXA4 group were intraperitoneally injected with LXA4 (40 ng/kg) once daily for 3 days following 12 weeks of high-fat diet (HFD) feeding. LXA4 receptor antagonist, Boc-2, was administered in LXA4/Boc-2 group prior to LXA4 treatment to block the effects of LXA4. Renal morphology and function impairment were determined. Inflammation was tested by measuring serum and mRNA levels of pro-inflammatory cytokines and chemokines. HFD-induced activation of nuclear factor-kappa B (NF-κB) and phosphorylation of mitogen-activated protein kinases (MAPKs) were investigated by immunohistochemistry and western blot.

RESULTS

HFD-feeding caused significant renal injury, pathological changes and inflammation in model group mice. LXA4 injection significantly alleviated HFD-induced effects on renal morphology and functions, as demonstrated by lower kidney index, glomerular diameter, 24 h urine protein, urinary albumin creatinine ratio and renal histomorphology. Moreover, HFD-induced accumulation of pro-inflammatory cytokines and chemokines were obviously attenuated by LXA4 administration, so did the HFD-induced activation of NF-κB and ERK/p38 MAPK pathways. However, these effects were markedly abrogated by BOC-2 pretreatment.

CONCLUSION

LXA4 significantly attenuated HFD-induced renal inflammation and injury in ORG models, and these effects may be associated with the inhibition of activation of NF-κB and ERK/p38 MAPK pathways. The findings of our study may shed light on LXA4 showed a potential therapeutic application in ORG.

Increased circulating trimethylamine N-oxide contributes to endothelial dysfunction in a rat model of chronic kidney disease

Chronic kidney disease (CKD) is strongly associated with increased cardiovascular risk. Impaired endothelial function, a key initiating step in the pathogenesis of cardiovascular disease, has been reported in patients with CKD, but the mechanisms responsible for endothelial dysfunction in CKD remain elusive. Emerging evidence reveals that trimethylamine-N-oxide (TMAO), a gut microbiota-generated metabolite, is involved in the pathogenesis of many cardiovascular diseases. Circulating TMAO is elevated in CKD. Here we tested the hypothesis that elevated TMAO plays a contributory role in the pathogenesis of endothelial dysfunction in CKD. Rats underwent 5/6 nephrectomy to induce CKD or sham operation, and were treated with 1.0% 3,3-Dimethyl-1-butanol (DMB, an inhibitor of trimethylamine formation) or vehicle. Eight weeks after nephrectomy and DMB treatment, circulating TMAO levels were markedly elevated in CKD-vehicle rats compared with sham-vehicle rats, but were reduced in CKD-DMB rats. Acetylcholine-induced endothelium-dependent vasodilation was impaired in CKD-vehicle rats compared with sham-vehicle rats as indicated by reduced maximal relaxation (E_max) and decreased area under the curve (AUC). E_max and AUC were both normalized in CKD-DMB rats. No difference in sodium nitroprusside-induced endothelial-independent vasodilation was observed across groups. Molecular studies revealed that endothelial nitric-oxide synthase activity was decreased, while superoxide production and proinflammatory cytokine expression were increased in the aorta of CKD-vehicle rats compared with sham-vehicle rats. Of note, the abnormalities in above molecular parameters were completely restored in CKD-DMB rats. These results suggest that CKD elevates circulating TMAO levels, which may reduce eNOS-derived NO production by increasing vascular oxidative stress and inflammation, contributing to CKD-associated endothelial dysfunction and cardiovascular disease.

Combination treatment with quercetin and resveratrol attenuates high fat diet-induced obesity and associated inflammation in rats via the AMPKα1/SIRT1 signaling pathway

Diet-induced obesity is associated with systemic inflammation, which is considered to originate predominantly from the adipose tissue. Quercetin and resveratrol are two dietary polyphenols that exhibit anti-inflammatory properties and anti-insulin resistance when administered in isolation or combination (CQR). It remains unknown whether CQR reduces high fat diet (HFD)-induced obesity and inflammation in rats. In the current study, 46 male Wistar rats were divided into two groups, one of which was fed a normal diet (ND, 5.4% fat, w/w) and one of which was fed a HFD (45% fat, w/w) for 3 weeks. Following removal of the 12 most obesity-resistant rats from the HFD group, the remaining rats were divided into two sub-groups: A HFD group and a HFD+CQR group (administered 120 mg/kg/day resveratrol and 240 mg/kg/day quercetin). The results revealed that the HFD+CQR group had significantly lower body weights at 11 weeks compared with the HFD group and had significantly reduced visceral adipose tissue weights and adipocyte sizes. Serum lipid profiles were also significantly ameliorated in the HFD+CQR group. CQR attenuated the expression of systemic proinflammatory adipokines, including leptin, tumor necrosis factor-α, monocyte chemoattractant protein-1 and interleukin-6. It also reduced the recruitment of mast cells to the epididyotic adipose tissue (EAT). Furthermore, CQR reversed the HFD-induced suppression of 5′-adenosine monophosphate-activated protein kinase α1 (AMPKα1) phosphorylation and sirtuin 1 (SIRT1) expression in EAT. In conclusion, CQR may suppress obesity and associated inflammation via the AMPKα1/SIRT1 signaling pathway in rats fed a HFD.

Vinpocetine mitigates proteinuria and podocytes injury in a rat model of diabetic nephropathy

Podocyte injury and glomerular basement membrane thickening have been considered as essential pathophysiological events in diabetic nephropathy. The aim of this study was to investigate the possible beneficial effects of vinpocetine on diabetes-associated renal damage. Male Wistar rats were made diabetic by injection of streptozotocin (STZ). Diabetic rats were treated with vinpocetine in a dose of 20mg/kg/day for 6 weeks. Treatment with vinpocetine resulted in a marked decrease in the levels of blood glucose, glycosylated haemoglobin, creatinine, blood urea nitrogen, urinary albumin and albumin/creatinine ratio along with an elevation in creatinine clearance rate. The renal contents of advanced glycation end-products, interleukin-10, tissue growth factor-β, nuclear factor (NF)-κB and Ras-related C3 botulinum toxin substrate 1 (Rac 1) were decreased. Renal nephrin and podocin contents were increased and their mRNA expressions were replenished in vinpocetine-treated rats. Moreover, administration of vinpocetine showed improvements in oxidative status as well as renal glomerular and tubular structures. The current investigation revealed that vinpocetine ameliorated the STZ-induced renal damage. This beneficial effect could be attributed to its antioxidant and antihyperglycemic effects parallel to its ability to inhibit NF-κB which eventually modulated cytokines production as well as nephrin and podocin proteins expression.

Green Tea Polyphenols, Mimicking the Effects of Dietary Restriction, Ameliorate High-Fat Diet-Induced Kidney Injury via Regulating Autophagy Flux

Epidemiological and experimental studies reveal that Western dietary patterns contribute to chronic kidney disease, whereas dietary restriction (DR) or dietary polyphenols such as green tea polyphenols (GTPs) can ameliorate the progression of kidney injury. This study aimed to investigate the renal protective effects of GTPs and explore the underlying mechanisms. Sixty Wistar rats were randomly divided into 6 groups: standard diet (STD), DR, high-fat diet (HFD), and three diets plus 200 mg/kg(bw)/day GTPs, respectively. After 18 weeks, HFD group exhibited renal injuries by increased serum cystatin C levels and urinary N-acetyl-β-d-glucosaminidase activity, which can be ameliorated by GTPs. Meanwhile, autophagy impairment as denoted by autophagy-lysosome related proteins, including LC3-II, Beclin-1, p62, cathepsin B, cathepsin D and LAMP-1, was observed in HFD group, whereas DR or GTPs promoted renal autophagy activities and GTPs ameliorated HFD-induced autophagy impairment. In vitro, autophagy flux suppression was detected in palmitic acid (PA)-treated human proximal tubular epithelial cells (HK-2), which was ameliorated by epigallocatechin-3-gallate (EGCG). Furthermore, GTPs (or EGCG) elevated phosphorylation of AMP-activated protein kinase in the kidneys of HFD-treated rats and in PA-treated HK-2 cells. These findings revealed that GTPs mimic the effects of DR to induce autophagy and exert a renal protective effect by alleviating HFD-induced autophagy suppression.

Resveratrol improves mitochondrial function in the remnant kidney from 5/6 nephrectomized rats

Mitochondrial dysfunction is involved in the pathogenesis of chronic kidney disease (CKD). Resveratrol has been demonstrated to be beneficial for the recovery of kidney diseases. In this study, the 5/6 nephrectomized rat was used as a CKD model and the TGF-β1-exposed mouse mesangial cells were used as an in vitro model. Pathological examination showed that resveratrol treatment attenuated glomerular injury in the remnant kidney of 5/6 nephrectomized rat. Additionally, resveratrol improved mitochondrial function in vivo and in vitro, as evidenced by increasing mitochondrial membrane potential, increasing ATP, decreasing reactive oxygen species production and enhancing activities of complex I and III. Furthermore, the dysregulated expressions of electron transport chain proteins and fission/fusion proteins in the kidney of 5/6 nephrectomize rats and TGF-β1-exposed mesangial cells were restored by resveratrol. Finally, upregulated sirt1 and PGC-1α deacetylation were found after treatment with resveratrol in vivo and in vitro, which may contribute to the mitochondrial protective effects of resveratrol. The results demonstrate that resveratrol protects the mitochondria of kidney in 5/6 nephrectomized rats and TGF-β1 induced mesangial cells. The study provides new insights into the renoprotective mechanisms of resveratrol.

Adipocytes play an etiological role in the podocytopathy of high-fat diet-fed rats

Obesity is a risk factor that promotes progressive kidney disease. Studies have shown that an adipocytokine imbalance contributes to impaired renal function in humans and animals, but the underlying interplay between adipocytokines and renal injury remains to be elucidated. We aimed to investigate the mechanisms linking obesity to chronic kidney disease. We assessed renal function in high-fat (HF) diet-fed and normal diet-fed rats, and the effects of preadipocyte- and adipocyte-conditioned medium on cultured podocytes. HF diet-fed and normal diet-fed Sprague Dawley rats were used to analyze the changes in plasma BUN, creatinine, urine protein and renal histology. Additionally, podocytes were incubated with preadipocyte- or adipocyte-conditioned medium to investigate the effects on podocyte morphology and protein expression. In the HF diet group, 24 h urinary protein excretion (357.5 ± 64.2 mg/day vs 115.9 ± 12.4 mg/day, P < 0.05) and the urine protein/creatinine ratio were significantly higher (1.76 ± 0.22 vs 1.09 ± 0.15, P < 0.05), increased kidney weight (3.54 ± 0.04 g vs 3.38 ± 0.04 g, P < 0.05) and the glomerular volume and podocyte effacement increased by electron microscopy. Increased renal expression of desmin and decreased renal expression of CD2AP and nephrin were also seen in the HF diet group (P < 0.05). Furthermore, we found that adipocyte-conditioned medium-treated podocytes showed increased desmin expression and decreased CD2AP and nephrin expression compared with that in preadipocyte-conditioned medium-treated controls (P < 0.05). These findings show that adipocyte-derived factor(s) can modulate renal function. Adipocyte-derived factors play an important role in obesity-related podocytopathy.

Renoprotective effect of a combination of garlic and telmisartan against ischemia/reperfusion-induced kidney injury in obese rats

Obesity enhances the frequency and severity of acute kidney injury (AKI). Telmisartan pre-treatment was used experimentally in the amelioration of ischemia/reperfusion (IR)-induced AKI. However, there is a lack of evidence regarding its beneficial effects on AKI in obese animals. The present study, therefore, aimed to explore the protective effects of garlic and/or telmisartan against renal damage induced by unilateral IR in obese rats. Meloxicam was used as a standard anti-inflammatory agent. Prophylactic oral administration of meloxicam (3 mg kg(-1)), garlic (500 mg kg(-1)) and/or telmisartan (5 and 10 mg kg(-1)) for 4 wk protected against renal function deterioration induced by IR in obese rats. Both doses of telmisartan significantly reduced serum total cholesterol and triacyglycerol levels as well as peri-renal adipocytes size and renal fibrosis. Renal nuclear factor-kappa B immunoreactivity, tumor necrosis factor-alpha content as well as interleukin-10, adiponectin receptor 1 and macrophages (M1, M2) polarization markers (CD11c, CD206) mRNA expressions were down-regulated in ischemic kidney tissues and white adipose tissues around them by all treatments. Moreover, garlic, telmisartan and their combinations significantly suppressed oxidative stress in renal ischemic tissues. Histological picture was also improved by these treatments. Interestingly, the combinations provided a greater protection than their monotherapy in a dose-dependent manner. We suppose that this combination may be a promising prophylactic regimen for managing AKI in case of obesity. Thus, future experimental and clinical large-scale studies are necessary.

Combination of melatonin and certain drugs for treatment of diabetic nephropathy in streptozotocin-induced diabetes in rats

Diabetic nephropathy is a major complication of diabetes and a leading cause of end-stage renal failure in many developed countries. The study aimed to evaluate the efficiency of certain drugs and melatonin in the treatment of nephropathy secondary to diabetes. Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (50 mg/kg body weight). Three days after induction of diabetes (460-500 mg/dl), rats were treated daily for 60 days with Rowatinex, melatonin, Rowatinex + melatonin, Amosar (Losartan Potassium) (LSP) and LSP + melatonin. The evaluations were made by measuring blood urea nitrogen (BUN), serum uric acid, serum creatinine, urine creatinine, creatinine clearance, nitric oxide, malondialdehyde, superoxide dismutase, glutathione, total antioxidant capacity, kidney injury molecule-1, heat shock protein-70, caspase-3, transforming growth factor β1, and DNA degradation by comet assay and total protein contents. The histopathological picture of the kidneys and pancreases was confirmed in our results. Diabetic rats showed drastic changes in all the measured parameters. Treatment with melatonin and the selected drugs revealed amelioration levels with variable degrees. In conclusion, the combination of LSP and melatonin had the most potent effect on treating the deleterious action of diabetes on rat kidney.

Protective effects of Brassica oleracea sprouts extract toward renal damage in high-salt-fed SHRSP: role of AMPK/PPARα/UCP2 axis

OBJECTIVES

Renal damage precedes occurrence of stroke in high-sodium/low-potassium-fed stroke-prone spontaneously hypertensive rat (SHRSP). We previously reported a marked suppression of uncoupling protein-2 (UCP2) upon high-salt Japanese-style diet in SHRSP kidneys. Vegetable compounds are known to exert protective effects in cardiovascular diseases. We aimed at evaluating the impact of Brassica oleracea sprouts juice toward renal damage in Japanese diet-fed SHRSP and exploring the role of 5'-adenosine monophosphate-activated protein kinase (AMPK)/NAD-dependent deacetylase sirtuin-1 (SIRT1)/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α)/peroxisome proliferator-activated receptor-α (PPARα)/UCP2 axis.

METHODS

SHRSP received Japanese diet for 4 weeks. A group of SHRSP received Japanese diet and B. oleracea. A third group received Japanese diet, B. oleracea, and PPARα inhibitor (GW6471). A group of SHRSP fed with regular diet served as control.

RESULTS

Japanese diet induced marked increases of oxidative stress, inflammation, and proteinuria, along with glomerular and tubular damage, as compared with regular diet. A significant suppression of AMPK/UCP2 pathway was observed. Despite Japanese diet feeding, concomitant administration of B. oleracea prevented oxidative stress accumulation, inflammation, renal damage, and proteinuria. All components of the UCP2 regulatory pathway were significantly increased by B. oleracea. Superoxide dismutase 2 and phosphoendothelial nitric oxide synthase were also stimulated. Addition of PPARα inhibitor to B. oleracea and Japanese diet significantly reduced the B. oleracea beneficial effects. SBP levels were comparable among the different groups of rats.In vitro, UCP2 inhibition by genipin offset the antioxidant effect of B. oleracea in renal mesangial and proximal tubular cells.

CONCLUSION

B. oleracea administration prevented renal damage in salt-loaded SHRSP, independently from SBP, with parallel stimulation of AMPK/SIRT1/PGC1α/PPARα/UCP2 axis. Stimulation of the latter mechanism may provide relevant renal protective effect and play a therapeutic role in target organ damage progression in hypertension.

Apple Polyphenols Decrease Atherosclerosis and Hepatic Steatosis in ApoE-/- Mice through the ROS/MAPK/NF-κB Pathway

In this study, we examined the effects of apple polyphenols (APs) on hyperlipidemia, atherosclerosis, hepatic steatosis and endothelial function and investigated the potential mechanisms. ApoE^−/− mice were fed a western-type diet and orally treated with APs (100 mg/kg) or atorvastatin (10 mg/kg) for 12 weeks. Hyperlipidemia and atherosclerosis in the aortic sinuses and, and hepatic lipidosis were measured. The treatment with APs or atorvastatin induced a remarkable reduction in the atherosclerotic lesions and hepatic steatosis and decreased the levels of low-density lipoprotein, triglyceride, CCL-2 and VCAM-1 levels in the plasma. Conversely, the APs significantly increased the plasma levels of high-density lipoprotein (HDL) cholesterol and markedly up-regulated the glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) levels in liver tissues. Moreover, the APs treatment modulated lipid metabolism by up-regulating the transcription of associated hepatic genes including PPARα, while down-regulating the transcription of SCAP and its downstream genes associated with lipid synthesis in the liver. Histological assessment showed that the APs treatment also reduced the macrophage infiltration in the aortic root plaque and the inflammatory cells infiltrations to the liver tissues. Moreover, we confirmed that the APs treatment greatly reduced the ox-LDL-induced endothelial dysfunction and monocyte adhesion to rat aortic endothelial cells (RAECs). Mechanistically, the APs treatment suppressed the ROS/MAPK/NF-κB signaling pathway, and consequently, reduced CCL-2, ICAM-1 and VCAM-1 expression. Our results suggest that the APs are a beneficial nutritional supplement for the attenuation of atherosclerosis.

Pathological changes in hippocampal neuronal circuits underlie age-associated neurodegeneration and memory loss: positive clue toward SAD

Among vertebrates hippocampus forms the major component of the brain in consolidating information from short-term memory to long-term memory. Aging is considered as the major risk factor for memory impairment in sporadic Alzheimer's disease (SAD) like pathology. Present study thus aims at investigating whether age-specific degeneration of neuronal-circuits in hippocampal formation (neural-layout of Subiculum-hippocampus proper-dentate gyrus (DG)-entorhinal cortex (EC)) results in cognitive impairment. Furthermore, the neuroprotective effect of Resveratrol (RSV) was attempted to study in the formation of hippocampal neuronal-circuits. Radial-Arm-Maze was conducted to evaluate hippocampal-dependent spatial and learning memory in control and experimental rats. Nissl staining of frontal cortex (FC), subiculum, hippocampal-proper (CA1→CA2→CA3→CA4), DG, amygdala, cerebellum, thalamus, hypothalamus, layers of temporal and parietal lobe of the neocortex were examined for pathological changes in young and aged wistar rats, with and without RSV. Hippocampal trisynaptic circuit (EC layerII→DG→CA3→CA1) forming new memory and monosynaptic circuit (EC→CA1) that strengthen old memories were found disturbed in aged rats. Loss of Granular neuron observed in DG and polymorphic cells of CA4 can lead to decreased mossy fibers disturbing neural-transmission (CA4→CA3) in perforant pathway. Further, intensity of nissl granules (stratum lacunosum moleculare (SLM)-SR-SO) of CA3 pyramidal neurons was decreased, disturbing the communication in schaffer collaterals (CA3-CA1) during aging. We also noticed disarranged neuronal cell layer in Subiculum (presubiculum (PrS)-parasubiculum (PaS)), interfering output from hippocampus to prefrontal cortex (PFC), EC, hypothalamus, and amygdala that may result in interruption of thought processes. We conclude from our observations that poor memory performance of aged rats as evidenced through radial arm maze (RAM) analysis was due to the defect in neuronal-circuits of hippocampus (DG-CA4-CA1-Sub) that were significantly damaged leading to memory impairment. Interestingly, RSV was observed to culminate pathological events in the hippocampal neuronal circuit during aging, proving them as potent therapeutic drug against age-associated neurodegeneration and memory loss.

Sodium nitrite potentiates renal oxidative stress and injury in hemoglobin exposed guinea pigs

Methemoglobin-forming drugs, such as sodium nitrite (NaNO2), may exacerbate oxidative toxicity under certain chronic or acute hemolytic settings. In this study, we evaluated markers of renal oxidative stress and injury in guinea pigs exposed to extracellular hemoglobin (Hb) followed by NaNO2 at doses sufficient to simulate clinically relevant acute methemoglobinemia. NaNO2 induced rapid and extensive oxidation of plasma Hb in this model. This was accompanied by increased renal expression of the oxidative response effectors nuclear factor erythroid 2-derived-factor 2 (Nrf-2) and heme oxygenase-1 (HO-1), elevated non-heme iron deposition, lipid peroxidation, interstitial inflammatory cell activation, increased expression of tubular injury markers kidney injury-1 marker (KIM-1) and liver-fatty acid binding protein (L-FABP), podocyte injury, and cell death. Importantly, these indicators of renal oxidative stress and injury were minimal or absent following infusion of Hb or NaNO2 alone. Together, these results suggest that the exposure to NaNO2 in settings associated with increased extracellular Hb may potentiate acute renal toxicity via processes that are independent of NaNO2 induced erythrocyte methemoglobinemia.