Decrease In Kidney Weight Research Articles

EFFECTS OF FEEDING GENETICALLY MODIFIED (GM) MAIZE ON OXIDATIVE STRESS PARAMETERS IN NEW ZEALAND RABBIT

In this study, we investigated the effects of Genetically Modified (GM) Maize on liver and kidney tissue weights, malondialdehyde (MDA) and glutathione (GSH) levels of liver and kidney tissues in New Zealand Rabbits. For this purpose, rabbits were divided into three groups: parental, first-generation and second-generation. Each group was divided into two sub-groups i.e. control group and the treatment group. Rabbits on the control group were fed with conventional maize (non-GM), whereas rabbits which are in the treatment groups were fed with GM maize. Six females and six male New Zealand rabbits were used per group. At the end of the experimental period, tissue samples were taken and tissue weights, MDA and GSH levels were determined. Overall, as the generations progressed, a statistically significant increase in liver weights and a decrease in kidney weights were observed. There was no statistically significant change as regards MDA and GSH levels of liver and kidney tissues of groups without GM maize inclusion in the diet. However in all three-generation of GM maize treated groups, there was a significant decrease in GSH levels and a significant increase in MDA levels were observed.

Role of caftaric acid in lead-associated nephrotoxicity in rats via antidiuretic, antioxidant and anti-apoptotic activities.

Background Lead is a toxic metal that is widely distributed in the environment where caftaric acid (CA) is the ester form of caffeic acid where CA is the major dietary polyphenol present in various foods and beverages. The aim of this study was to evaluate the effect of CA in lead acetate (LA)-associated nephrotoxicity through antidiuretic, antioxidant and anti-apoptotic activities. Methods Forty-eight male albino rats divided into six equal groups; group 1 control injected intraperitoneally (ip) with saline (1 mL/kg of bw) over two weeks period, group 2 injected ip with CA (80 mg/kg of bw) over two weeks period, groups 3, 4, 5 and 6 injected ip with 100 μmol/kg of bw LA over two weeks period where groups 4, 5 & 6 co-injected ip with 1-deamino-8-D-arginine vasopressin (dDAVP) drug (1 mg/kg of bw), CA (40 mg/kg of bw), and CA (80 mg/kg of bw), respectively. Results The results obtained revealed that LA induced a significant decrease in kidney weight and serum sodium, potassium and chloride, but caused a significant increase in urinary volume, urinary excretion of sodium, potassium and chloride, serum urea, creatinine and uric acid. The LA also caused a significant decrease in kidney superoxide dismutase, glutathione peroxidase and induced a significant decrease in glutathione level while caused an increase in lipid peroxidation level. In addition, LA caused a decrease in p53 expression while induced an increase in bcl-2 expression in the kidney tissues. Co-injection of CA to LA-treated group restored all the above parameters to approach the normal values. The results supported with histopathological examinations. Conclusions In conclusion, the effect of CA on LA-related nephrotoxicity was occurred through antidiuretic, antioxidant, anti-apoptotic activities where the effect of CA was dose dependent.

Ethyl silicate Documentation of proposed values of occupational exposure limits (OELs)

Ethyl silicate is a colorless liquid with a slightly perceptible odor. This compound finds numerous applications in many industrial branches, e.g., paint and lacquer, chemical (in chemical coatings which has a contact with food), pharmaceutical, semiconductor and in nanotechnology. It is also used as an agent to harden natural stone, terra-cotta, artificial marble, frescoes and clay and in pro-duction of waterproof and acidproof mortar and cements. According to the State Sanitary Inspection data, in Poland in 2007, 2010 and 2013, there were no workers Ortokrzemian tetraetylu. Dokumentacja proponowanych dopuszczalnych wielkości narażenia zawodowego 23 exposed to ethyl silicate at levels exceeding maxi-mum allowable concentration (MAC) of 80 mg/m3. Ethyl silicate is well absorbed via respiratory and alimentary tracts, but its absorption through the skin is rather poor. In workers exposed to ethyl sil-icate, irritating properties to eye and nasal mucosa have been observed. Data on chronic ethyl silicate effects in humans are not available in the literature. In laboratory animals, ethyl silicate acute toxicity expressed in median lethal doses is relatively low. Ethyl silicate shows a mild irritating effect on rab-bit’s eyes, it does not cause dermal irritation or al-lergic effects. There are no data on ethyl silicate chronic toxicity. Short-term and subchronic studies performed on mice and rats exposed to ethyl sili-cate through inhalation and after its administration in other ways showed except for necrotic lesions in the olfactory epithelium of nasal cavity (in mice), changes in the liver (in rats) and kidneys. The latter comprised interstitial inflammation and necrotic lesions in renal tubules. Short-term exposure of rats to high ethyl silicate concentrations induced its toxic effect also on lungs. Ethyl silicate mutagenic effect has not been re-vealed in Ames tests. On the basis of few data, it has been proved that this compound did not cause reproductive and developmental toxicity. This compound has not been categorized by the Inter-national Agency for Research on Cancer (IARC) with respect to its potential carcinogenic risk. The presented evidence shows that the major toxic effect of ethyl silicate at high concentrations (over 2000 mg/m3) is eye and nasal mucosa irritation in humans, whereas the nephrotoxic effect and dam-age to the olfactory epithelium of nasal cavity are observed in laboratory animals. On the basis of the nephrotoxic effect of ethyl sili-cate, its maximum allowable concentration (MAC) was calculated. The results of two independent in-halation experiments in mice were used to deter-mine NOAEL value. Inhalation exposure of mice to ethyl silicate at concentration of 430 mg/m3 (50 ppm) for 90 days or 2 and 4 weeks did not cause nephrotoxic effects. This compound at higher con-centrations caused nephrotoxicity. Exposure to concentration of 760 mg/m3 (88 ppm) caused sig-nificant decrease in kidney weight, and after expo-sure to concentration of 865 mg/m3 (100 ppm) in 20% of animals interstitial inflammation of kidney tubules have been observed. The authors of the documentation proposed to adopt a concentration of 430 mg/m3 as NOAEC value of ethyl silicate for the nephrotoxic effects observed in mice. After adopting relevant uncertainty coefficients (total value, 8) the calculated MAC value for ethyl silicate is 54 mg/m3. Taking into consideration the fact that in 2008 SCOEL proposed a concentration of 44 mg/m3 as 8-h TWA for ethyl silicate, which was based on the same effects (nephrotoxicity) and NOAEC value adopted from the same experiments, it was pro-posed to assume a concentration of 44 mg/m3 as MAC value of ethyl silicate. This substance is in-cluded in the directive establishing the IV list of in-dicative occupational exposure limit values with-out establishing a short-term STEL value. The proposed MAC value for ethyl silicate should protect workers against systemic effect and poten-tial irritating effect. There are no reasons for adopt-ing STEL and BEI values for this compound.

Therapeutic effect of Arctium lappa in Schistosoma haematobium associated kidney disturbance: biochemical and molecular effects.

Schistosoma haematobium (S. haematobium) infection has been found to be strongly associated with bladder cancer, which necessitates for discover of a natural new therapeutic agent. The aim of this study was to evaluate the therapeutic effect of Arctium lappa seed extract in S. haematobium associated kidney disturbance. Forty male albino mice were used and divided into four equal groups; group 1 control includes non-infected healthy mice, groups 2, 3 and 4 subcutaneous infected with S. haematobium cercariae. Groups 3 co-treated daily with oral dose of A. lappa seed extract (300mg/kg, bwt) for 15days in the same time of S. haematobium infection. Groups 4 post-treated daily for 15days with oral dose of A. lappa seed extract (300mg/kg, bwt) after 15days of S. haematobium infection. The results obtained revealed that S. haematobium significantly decreased kidney weight and serum sodium, potassium and chloride, but increased urinary volume, urinary excretion of sodium, potassium and chloride, serum urea, creatinine and uric acid. Schistosoma haematobium also significantly decreased kidney superoxide dismutase, glutathione peroxidase and reduced glutathione levels while increased kidney lipid peroxidation level. Co- and post-treatment with A. lappa seed extract restore all the above parameters to approach the normal values. These results were supported with histopathological examinations. In conclusion, A. lappa seed extract has therapeutic effect in kidney disturbance caused by S. haematobium where co-treatment of A. lappa seed extract was more effective than post-treatment of the extract.

A cisplatin‑incorporated liposome that targets the epidermal growth factor receptor enhances radiotherapeutic efficacy without nephrotoxicity.

Radiotherapy (RT) is one of the major modalities for non‑small cell lung cancer (NSCLC), but its efficacy is often compromised by cellular resistance caused by various mechanisms including the overexpression of epidermal growth factor receptor (EGFR). Although cis‑diamminedichloroplatinum(Ⅱ) (cisplatin, CDDP) has been well characterized as an effective radiosensitizer, its clinical application is limited by its severe nephrotoxic effects. In our current study, we developed a CDDP‑incorporated liposome (LP) conjugated with EGFR antibodies (EGFR:LP‑CDDP) and evaluated its potential to radiosensitize EGFR‑overexpressing cells without exerting nephrotoxic effects. EGFR:LP‑CDDP showed higher cytotoxicity than non‑targeting liposomal CDDP (LP‑CDDP) in the cells expressing EGFR in vitro. In an A549 cell‑derived xenograft tumor mouse model, increased delays in tumor growth were observed in the mice treated with a combination of EGFR:LP‑CDDP and radiation. Notably, the EGFR:LP‑CDDP‑treated animals showed no differences in body weight loss, survival rates of nephrotoxicity compared with untreated control mice. In contrast, the use of CDDP caused lower body weights and poorer survival outcomes accompanied by a significant level of nephrotoxicity [e.g., decreased kidney weight, increased blood urea nitrogen (BUN) and creatinine, and pathological change]. These findings suggest the feasibility of using EGFR:LP‑CDDP to radiosensitize cells in a targeted manner without inducing nephrotoxic effects. This compound may therefore have clinical potential as part of a tailored chemoradiotherapy strategy.

Steviol retards renal cyst growth through reduction of CFTR expression and inhibition of epithelial cell proliferation in a mouse model of polycystic kidney disease (690.2)

Cyst growth in ADPKD is associated with cAMP‐activated proliferation of cyst‐lining epithelial cells and transepithelial fluid secretion into the cyst lumen via CFTR chloride channel. It will eventually lead to renal insufficiency and renal failure for which no effective treatment is currently available. We previously reported that steviol retards MDCK cyst growth by inhibiting CFTR channel activity and promoting proteasomal‐mediated CFTR degradation. However, the MDCK cells do not carry the mutated PKD genes and do not recapitulate the complexity of PKD pathogenesis. Therefore, it is imperative to examine the effect of steviol in animal model that closely resembles PKD. In this study, we determined the effect of steviol on renal cyst growth in an orthologous mouse model of human ADPKD (Pkd1flox/flox :Pkhd1‐Cre). The results showed that daily treatment with both 200 mg/kg BW of steviol and 1,000 mg/kg BW of stevioside for 14 days markedly decreased kidney weight and cystic index in these mice. Surprisingly, only steviol markedly reduced blood urea nitrogen and creatinine values. It also reduced cell proliferation but had no effect on cell apoptosis. In addition, steviol suppressed CFTR and mTOR/S6K expressions but stimulated AMP‐activated protein kinase (AMPK) in renal cyst‐lining epithelial cells. These findings indicate that steviol slows cyst progression in PKD mouse model, in part, through the activation of AMPK which subsequently inhibits both CFTR expression and renal epithelial cell proliferation via mTOR/S6K pathway. Most importantly, steviol could markedly improve kidney function in a mouse model of PKD. Steviol thus has potential application for further development as therapeutic compound for the treatment of polycystic kidney disease.Grant Funding Source: Supported by Thailand Research Fund and Faculty of Science, Mahidol University, Bangkok, Thailand

Canola oil influence on azoxymethane-induced colon carcinogenesis, hypertriglyceridemia and hyperglycemia in Kunming mice.

Azoxymethane (AOM) is a potent genotoxic carcinogen which specifically induces colon cancer. Hyperlipidemia and diabetes have several influences on colon cancer development, with genetic and environmental exposure aspects. Here, we investigated plasma lipid and glucose concentrations in Kunming mice randomized into four groups; control (no AOM or oil exposure), AOM control, AOM + pork oil, and AOM + canola oil. Aberrant crypt foci (ACF), plasma cholesterol, plasma triglyceride, plasma glucose and organ weight were examined 32 weeks after AOM injection. Results revealed that AOM exposure significantly increased ACF number, plasma triglyceride and glucose level. Further, male mice displayed a much higher plasma triglyceride level than female mice in the AOM control group. Dietary fat significantly inhibited AOM-induced hypertriglyceridemia, and canola oil had stronger inhibitory effect than pork oil. AOM-induced hyperglycemia had no sex-difference and was not significantly modified by dietary fat. However, AOM itself not change plasma cholesterol level. AOM significantly increased liver and spleen weight in male mice, but decreased kidney weight in female mice. On the other hand, mice testis weight decreased when fed canola oil. AOM could induce colorectal carcinogenesis, hypertriglyceridemia and hyperglycemia in Kunming mice at the same time, with subsequent studies required to investigate their genome association.

Steviol retards renal cyst growth through reduction of CFTR expression and inhibition of epithelial cell proliferation in a mouse model of polycystic kidney disease

Cyst enlargement in autosomal dominant polycystic kidney disease (ADPKD) is associated with cAMP-activated proliferation of cyst-lining epithelial cells and transepithelial fluid secretion into the cyst lumen via cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel leading to renal failure for which no effective treatment is currently available. We previously reported that steviol retards Madin–Darby canine kidney (MDCK) cyst enlargement by inhibiting CFTR channel activity and promoting proteasomal-mediated CFTR degradation. It is imperative to examine the effect of steviol in animal models of ADPKD. Therefore, we examined the effect of steviol on renal cyst growth in an orthologous mouse model of human ADPKD (Pkd1flox/flox:Pkhd1-Cre). The results showed that daily treatment with both 200mg/kg BW of steviol and 1000mg/kg BW of stevioside for 14 days markedly decreased kidney weight and cystic index in these mice. However, only steviol markedly reduced blood urea nitrogen and creatinine values. Steviol also reduced cell proliferation but had no effect on cell apoptosis. In addition, steviol suppressed CFTR and mTOR/S6K expression in renal cyst-lining epithelial cells. Interestingly, steviol was found to stimulate AMP-activated protein kinase (AMPK). Our findings indicate that steviol slows cyst progression in ADPKD mouse model, in part, through the activation of AMPK which subsequently inhibits CFTR chloride channel expression and inhibits renal epithelial cell proliferation via mTOR/S6K pathway. Most importantly, steviol could markedly improve kidney function in a mouse model of ADPKD. Steviol thus has potential application for further development as a therapeutic compound for the treatment of polycystic kidney disease.

Protective effects of polysaccharides from Lilium lancifolium on streptozotocin-induced diabetic mice

In this study, the protective effect of Lilium lancifolium polysaccharides (LLP) on streptozotocin (STZ)-induced diabetic mice and possible mechanism were investigated. The diabetic mice were administered with LLP for 28 days. The results showed that oral administration of LLP could significantly decrease blood glucose level and increase body weight loss in STZ-induced diabetic mice. LLP also significantly increased the activities of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) and decreased the level of malondialdehyde (MDA) in serum, liver, and kidney in STZ-induced diabetic mice. Moreover, histopathological examination showed that LLP could markedly improve the structure integrity of pancreatic islet tissue in STZ-induced diabetic mice. However, LLP had no significant effect on organ weight of liver and pancreas of diabetic mice, but significantly decreased kidney weight compared with diabetic control mice. This study suggested that LLP had hypoglycemic and antioxidant properties and could provide protective effect on STZ-induced diabetic mice.

Therapeutic Effects of Human Mesenchymal Stem Cells in Wistar-Kyoto Rats with Anti-Glomerular Basement Membrane Glomerulonephritis

IntroductionMultipotent mesenchymal stem cells (MSCs) have become a promising therapeutic approach in many clinical conditions. The hypothesis that MSCs can provide a potential therapy for human anti-glomerular basement membrane (GBM) glomerulonephritis (GN) was tested.MethodsNephrotoxic serum nephritis was induced in Wistar-Kyoto rats on day 0. Groups of animals were given either human MSCs (hMSCs, 3×106) or vehicle by intravenous injection on day 4; all rats were sacrificed at either day 7 or day 13.ResultsFluorescently labeled hMSCs were localized in glomeruli and tubulointerstitium 5 h after hMSC administration and persisted until 48 h, but hMSCs were barely detectable after 7 days. hMSC-treated rats had decreased kidney weight, proteinuria, and glomerular tuft area at each time point. The serum creatinine level and degree of glomerular crescent formation were decreased by hMSC treatment on day 13. ED1-positive macrophages, CD8-positive cells, and TUNEL-positive apoptotic cells in glomeruli were reduced by hMSC treatment on day 7, and this trend in apoptotic cells persisted to day 13. Renal cortical mRNA for TNF-α, IL-1β, and IL-17, and the serum IL-17A level were decreased, whereas renal cortical mRNA for IL-4 and Foxp3 and the serum IL-10 level were increased in the MSC-treated group on day 7. Collagen types I and III and TGF-β mRNA were decreased by hMSC treatment on day 13.ConclusionThe present results demonstrated that anti-inflammatory and immunomodulatory effects were involved in the mechanism of attenuating established experimental anti-GBM GN by hMSCs. These results suggest that hMSCs are a promising therapeutic candidate for the treatment of anti-GBM GN.

Lead-Induced Reduction In Body And Kidney Weight Of Wistar Albino Rats Ameliorated By Ginkgo Biloba Extract (EGb 761)

Objective To observe the effects of lead acetate on body and kidney weight of Wistar albino rats and the protective role of EGb 761 on weight changes. 1.2 Methodology One hundred and twenty young male Wistar albino rats were randomly selected and divided into three groups, A, B and C, comprising of 40 animals. Each group was further divided into four subgroups according to the duration of treatment, i.e., one, two, four and six weeks. Group A animals (control) were given 0.5 ml normal saline intraperitoneally (IP) daily. Group B animals received lead acetate 8mg/kg body weight IP daily, whereas Group C animals received 100mg/kg body weight of EGb 761 through gavage and 8mg/kg body weight lead acetate through IP. Initial and final body weights were taken and recorded. After sacrificing the animals, the kidneys were retrieved, dried and weighed using the Sartorius balance. 1.3 Results Group B animals showed overall decrease in the body weight, which was non-significant (p>0.05) after one week and became highly significant (p 0.05) after one and two weeks, while became significant (p 0.05) decrease in kidney weight of group B rats after one week whereas the decrease was highly significant (p 0.05) after six weeks of treatment. 1.4 Conclusion EGb 761 effectively ameliorated the lead-induced changes in body and kidneys weight of the albino rats.

Chelidonium majus leaves methanol extract and its chelidonine alkaloid ingredient reduce cadmium-induced nephrotoxicity in rats

The kidney is one of the critical target organs for chronic cadmium toxicity. Cadmium is a cumulative nephrotoxicant, and preferentially accumulates and persists in the kidneys. The natriuretic and antidiuretic effects of methyl alcohol extracts of Chelidonium majus L. (C. majus) leaves were evaluated in kidney of cadmium-intoxicated rats. Ninety-six male Sprague-Dawley Albino rats were divided into two major groups (toxicity and biochemical, 60 and 36 rats, respectively). There was a decrease in kidney weight and serum electrolytes, but an increase in urinary volume, excretion of electrolytes, serum urea and creatinine, after 9weeks of cadmium chloride intoxication. Treatment of C. majus methyl alcohol extract for 10weeks starting 1week before cadmium administration shifted the above parameters towards the normal values. These results were supported by molecular and histological investigations. Treatment with C. majus methyl alcohol extract has natriuretic and antidiuretic effects against cadmium-induced nephrotoxicity in rats.

Early protective effect of mitofusion 2 overexpression in STZ-induced diabetic rat kidney

Diabetic nephropathy (DN) is a serious complication of diabetes with a poorly defined etiology and limited treatment options. Early intervention is key to preventing the progression of DN. Mitofusin 2 (Mfn2) regulates mitochondrial morphology and signaling, and is involved in the pathogenesis of numerous diseases. Furthermore, Mfn2 is also closely associated with the development of diabetes, but its functional roles in the diabetic kidney remain unknown. This study investigated the effect of Mfn2 at an early stage of DN. Mfn2 was overexpressed by adenovirus-mediated gene transfer in streptozotocin-induced diabetic rats. Clinical parameters (proteinuria, albumin/creatinine ratio), pathological changes, ultra-microstructural changes in nephrons, expression of collagen IV and phosph-p38, ROS production, mitochondrial function, and apoptosis were evaluated and compared with diabetic rats expressing control levels of Mfn2. Endogenous Mfn2 expression decreased with time in DN. Compared to the blank transfection control group, overexpression of Mfn2 decreased kidney weight relative to body weight, reduced proteinuria and ACR, and improved pathological changes typical of the diabetic kidney, like enlargement of glomeruli, accumulation of ECM, and thickening of the basement membrane. In addition, Mfn2 overexpression inhibited activation of p38, and the accumulation of ROS; prevented mitochondrial dysfunction; and reduced the synthesis of collagen IV, but did not affect apoptosis of kidney cells. This study demonstrates that Mfn2 overexpression can attenuate pathological changes in the kidneys of diabetic rats. Further studies are needed to clarify the underlying mechanism of this protective function. Mfn2 might be a potential therapeutic target for the treatment of early stage DN.

PPAR-γ agonist ameliorates kidney and liver disease in an orthologous rat model of human autosomal recessive polycystic kidney disease

In autosomal recessive polycystic kidney disease (ARPKD), progressive enlargement of fluid-filled cysts is due to aberrant proliferation of tubule epithelial cells and transepithelial fluid secretion leading to extensive nephron loss and interstitial fibrosis. Congenital hepatic fibrosis associated with biliary cysts/dilatations is the most common extrarenal manifestation in ARPKD and can lead to massive liver enlargement. Peroxisome proliferator-activated receptor γ (PPAR-γ), a member of the ligand-dependent nuclear receptor superfamily, is expressed in a variety of tissues, including the kidneys and liver, and plays important roles in cell proliferation, fibrosis, and inflammation. In the current study, we determined that pioglitazone (PIO), a PPAR-γ agonist, decreases polycystic kidney and liver disease progression in the polycystic kidney rat, an orthologous model of human ARPKD. Daily treatment with 10 mg/kg PIO for 16 wk decreased kidney weight (% of body weight), renal cystic area, serum urea nitrogen, and the number of Ki67-, pERK1/2-, and pS6-positive cells in the kidney. There was also a decrease in liver weight (% of body weight), liver cystic area, fibrotic index, and the number of Ki67-, pERK1/2-, pERK5-, and TGF-β-positive cells in the liver. Taken together, these data suggest that PIO inhibits the progression of polycystic kidney and liver disease in a model of human ARPKD by inhibiting cell proliferation and fibrosis. These findings suggest that PPAR-γ agonists may have therapeutic value in the treatment of the renal and hepatic manifestations of ARPKD.

Effect of Lactobacillus reuteri GMNL-263 treatment on renal fibrosis in diabetic rats

Hyperglycemia is the most important factor in the progression of renal fibrosis in diabetic kidney. Prevention and treatment of renal fibrosis may improve diabetic nephropathy. To explore whether probiotic Lactobacillus reuteri GMNL-263 treatment was linked to altered hyperglycemia-mediated renal fibrosis in diabetic kidney, the mechanisms of L. reuteri GMNL-263 treatment responsible for the inhibition of renal fibrosis in streptozotocin (STZ)-induced diabetic rats were examined. Diabetic rats were induced by intraperitoneal injection of STZ (50 mg/kg). Induction of diabetes was confirmed by measurement of the blood glucose using the glucose oxidase method, and hyperglycemic rats with levels >16 mmol/L were used. We found that L. reuteri GMNL-263 treatment caused reduction of glycated hemoglobin and blood glucose levels in STZ-induced diabetic rats for 28 days (all p<0.05). Treatment with L. reuteri GMNL-263 increased body weight but decreased kidney weight in diabetic rats as compared to diabetic control (p<0.05). In diabetic renal cortex, the Janus kinase 2/signal transducers and activators of transcription 1 (but not extracellular signal-regulated kinase/c-Jun N-terminal kinase/p38 mitogen-activated protein kinase) activation was markedly blocked by L. reuteri GMNL-263 treatment. The ability of L. reuteri GMNL-263 treatment to inhibit renal fibrosis was verified by the observation that it significantly decreased protein levels of plasminogen activator inhibitor-1, p21(Waf1/Cip1), α-smooth muscle actin, and fibronectin in diabetic renal cortex. The results obtained in this study indicate that L. reuteri GMNL-263 treatment may protect STZ-induced diabetic rats from hyperglycemia-enhanced renal fibrosis.

Effects of dietary consumption of cranberry powder on metabolic parameters in growing rats fed high fructose diets

The effect of dietary consumption of a cranberry powder (CP) containing increased amounts of procyanidins and other phytochemicals on metabolic parameters associated with metabolic syndrome was investigated in growing rats fed a high fructose diet. Dietary treatments were control (starch based), high fructose (HF), and HF containing either 3.3, 6.6, or 33 g CP/kg diet. Fasting plasma glucose and triglycerides tended to be higher with HF feeding and were reduced by feeding CP. The area under curve following an oral glucose tolerance test was 35-50% higher in animals fed HF diet vs. control and was decreased to control levels by the low or medium but not high CP diet. Feeding CP tended to lower fasting plasma insulin. Homeostatic models of insulin resistance (HOMA-IR) and β-cell function (HOMA-BCF) were lowest in animals fed low or medium CP diets (p < 0.05). Rats fed the control starch diet had slightly higher food intake, final body weight, and abdominal fat compared to animals fed other diets. Kidney weight was higher in HF group and feeding CP decreased kidney weight to normal levels. In the fed state, plasma triglyceride was increased with HF diet, whereas insulin was lower in animals fed HF diet. Overall, inclusion of CP in the diet was effective in modulating some aspects of metabolic parameters associated with metabolic syndrome and the medium level of CP in the diet produced a better response than the lower and higher CP levels.

Efecto de la restricción de aminoácidos excepto la metionina sobre el estrés oxidativo mitocondrial

Introduction Protein or methionine restriction in the diet is known to decrease reactive oxygen species (ROS) production and mitochondrial oxidative stress and to increase maximum longevity in rodents, which could explain how these changes also take place in dietary restriction. However, it is not known whether restriction of other amino acids is also involved. To clarify this question, we studied the effect of restricting all the amino acids, except methionine, of the semi-purified diet, AIN 93G, in Wistar rats. Material and methods Seven-week old male Wistar rats (n=16) were randomly divided into two groups: a control group and a group with 40% restriction of dietary amino acids except methionine. After 7 weeks of dietary treatment, the animals were sacrificed and their livers were extracted to isolate mitochondria immediately and measure ROS production and oxygen consumption; these data allowed the percentage of free radical leak to be calculated. Oxidative damage to mitochondrial DNA was calculated as 8-oxo-7,8-dihydro-2′-deoxyguanosine by HPLC-EC. Results At the end of the experimental period, a decrease in kidney weight was observed, but the weight of the liver, heart and brain was unchanged. ROS production in isolated liver mitochondria was unchanged with complex I (pyruvate/malate or glutamate/malate) or complex II (succinate) linked substrates. Maximum rates of ROS production significantly decreased with glutamate/malate+rotenone but not with pyruvate/malate+rotenone or with succinate. There were no changes in oxygen consumption with any substrate either in state 4 (resting) or in state 3 (phosphorylating). In agreement with the ROS production results, there were no differences between groups in oxidative damage to mitochondrial DNA. Conclusions Taken together with previous results concerning methionine restriction, the results obtained in the present study clearly show that the decrease in ingestion of only one molecule, methionine, causes the decrease in ROS production and oxidative damage to mitochondrial DNA that is observed in dietary restriction in relation to the decrease in the rate of aging.

Ginseng modifies the diabetic phenotype and genes associated with diabetes in the male ZDF rat

Asian ginseng (Panax ginseng) and its close relative North American ginseng (Panax quinquefolius) are perennial aromatic herbs that are widely used in Oriental medicine and have been acclaimed to have various health benefits including diabetes treatment. In this study, we compared the effects of a diet containing rosiglitazone to a diet containing ginseng (Panax quinquefolius) in male Zucker diabetic fatty (ZDF) rats. Animals were assigned to one of three diets: control, rosiglitazone (0.1 g/1 kg diet), or ginseng (10 g/1 kg diet). During the 11-week study, body weight, food intake, organ weight, blood glucose, plasma cholesterol, and plasma triglyceride levels were evaluated. Animals treated with rosiglitazone or ginseng exhibited increased body weight (p<0.05) and decreased kidney weight (p<0.05) compared to control animals. The rosiglitazone group demonstrated decreased food intake and plasma triglyceride levels versus the other groups (p<0.05). The ginseng group revealed decreased cholesterol levels relative to the control group (p<0.05). Furthermore, ginseng and rosiglitazone had marked effects on the expression of genes involved in PPAR actions and triglyceride metabolism compared to controls. In conclusion, ginseng modified the diabetic phenotype and genes associated with diabetes in the male ZDF rat. These data are encouraging, and warrant further research to determine the therapeutic value of this medicinal herb in treating human diabetes.

Liver-derived IGF-I regulates kidney size, sodium reabsorption, and renal IGF-II expression

The GH/-IGF-I axis is important for kidney size and function and may also be involved in the development of renal failure. In this study, the role of liver-derived endocrine IGF-I for kidney size and function was investigated in mice with adult liver-specific IGF-I inactivation (LI-IGF-I(-/-) mice). These mice have an 80-85% reduction of serum IGF-I level and compensatory increased GH secretion. Seven-month-old as well as 24-month-old LI-IGF-I(-/-) mice had decreased kidney weight. Glomerular filtration rate, assessed using creatinine clearance as well as creatinine clearance corrected for body weight, was unchanged. The 24-h urine excretion of sodium and potassium was increased in the LI-IGF-I(-/-) mice. In the 24-month-old mice, there was no between-group difference in kidney morphology. Microarray and real-time PCR (RT-PCR) analyses showed a high renal expression of IGF-II in the control mice, whereas in the LI-IGF-I(-/-) mice, there was a tissue-specific decrease in the renal IGF-II mRNA levels (-79%, P < 0.001 vs controls using RT-PCR). In conclusion, deficiency of circulating liver-derived IGF-I in mice results, despite an increase in GH secretion, in a global symmetrical decrease in kidney size, increased urinary sodium and potassium excretion, and a clear down regulation of renal IGF-II expression. However, the LI-IGF-I(-/-) mice did not develop kidney failure or nephrosclerosis. One may speculate that liver-derived endocrine IGF-I induces renal IGF-II expression, resulting in symmetrical renal growth.

Tolvaptan, an Orally Active Vasopressin V2‐Receptor Antagonist—Pharmacology and Clinical Trials

Tolvaptan is an orally effective nonpeptide arginine vasopressin (AVP) V(2)-receptor antagonist synthesized by Otsuka Pharmaceutical Co., Ltd. In in vitro receptor-binding studies, tolvaptan blocked the binding of [(3)H]AVP to human V(2) receptors with 29-fold greater selectivity than that for V(1a) receptors, and showed no inhibition of V(1b) receptors. Tolvaptan inhibited not only the binding of [(3)H]AVP but also the AVP-induced production of cyclic AMP in human V(2)-receptor-expressing HeLa cells. In addition, tolvaptan has no intrinsic V(2) receptor agonistic effect. In in vivo studies, tolvaptan showed marked aquaresis in healthy and diseased animals. In rat models with acute and chronic hyponatremia, tolvaptan improved hyponatremia, resulting in the prevention of death, and improved organ water retention. Tolvaptan reduced cardiac preload without unfavorable effects on renal functions, systemic hemodynamics, or circulating neurohormones in dogs with heart failure (HF). Furthermore, in animal models of human polycystic kidney disease (PKD), tolvaptan showed a decrease in kidney weight as well as in cyst and fibrosis volume. In clinical trials including the "ACTIV in CHF" study, tolvaptan in addition to standard therapy increased fluid loss resulting in decreased body weight, and improved edema and serum sodium without affecting blood pressure, heart rate, or renal functions in patients with HF. In patients with hyponatremia, treatment with tolvaptan without fluid restriction appeared to be more effective than fluid restriction alone at correcting hyponatremia without an increase in adverse events. A phase III trial EVEREST is currently being conducted to evaluate the long-term efficacy and safety of tolvaptan in hospitalized patients with severe HF. In conclusion, tolvaptan offers the possibility of a useful therapy in hyponatremia, congestive heart failure, and various other diseases that are associated with volume overload. Furthermore, tolvaptan is also expected to be effective in the treatment of PKD.