Role of ghrelin hormone in the development of alcohol-associated liver disease.

Fatty liver is the earliest response of the liver to excessive alcohol consumption. Previously we identified that chronic alcohol administration increases levels of stomach-derived hormone, ghrelin, which by reducing circulating insulin levels, ultimately contributes to the development of alcohol-associated liver disease (ALD). In addition, ghrelin directly promotes fat accumulation in hepatocytes by enhancing de novo lipogenesis. Other than promoting ALD, ghrelin is known to increase alcohol craving and intake. In this study, we used a ghrelin receptor (GHSR) knockout (KO) rat model to characterize the specific contribution of ghrelin in the development of ALD with emphasis on energy homeostasis. Male Wistar wild type (WT) and GHSR-KO rats were pair-fed the Lieber-DeCarli control or ethanol diet for 6 weeks. At the end of the feeding period, glucose tolerance test was conducted, and tissue samples were collected. We observed reduced alcohol intake by GHSR-KOs compared to a previous study where WT rats were fed ethanol diet ad libitum. Further, when the WTs were pair-fed to GHSR-KOs, the KO rats exhibited resistance to develop ALD through improving insulin secretion/sensitivity to reduce adipose lipolysis and hepatic fatty acid uptake/synthesis and increase fatty acid oxidation. Furthermore, proteomic data revealed that ethanol-fed KO exhibit less alcohol-induced mitochondrial dysfunction and oxidative stress than WT rats. Proteomic data also confirmed that the ethanol-fed KOs are insulin sensitive and are resistant to hepatic steatosis development compared to WT rats. Together, these data confirm that inhibiting ghrelin action prevent alcohol-induced liver and adipose dysfunction independent of reducing alcohol intake.

Alcohol-induced Golgiphagy is triggered by the downregulation of Golgi GTPase RAB3D.

The development of alcohol-associated liver disease (ALD) is associated with disorganized Golgi apparatus and accelerated phagophore formation. While Golgi membranes may contribute to phagophores, association between Golgi alterations and macroautophagy/autophagy remains unclear. GOLGA4/p230 (golgin A4), a dimeric Golgi matrix protein, participates in phagophore formation, but the underlying mechanism is elusive. Our prior research identified ethanol (EtOH)-induced Golgi scattering, disrupting intra-Golgi trafficking and depleting RAB3D GTPase from the trans-Golgi. Employing various techniques, we analyzed diverse cellular and animal models representing chronic and chronic/binge alcohol consumption. In trans-Golgi of non-treated hepatocytes, we found a triple complex formed between RAB3D, GOLGA4, and MYH10/NMIIB (myosin, heavy polypeptide 10, non-muscle). However, EtOH-induced RAB3D downregulation led to MYH10 segregation from the Golgi, accompanied by Golgi fragmentation and tethering of the MYH10 isoform, MYH9/NMIIA, to dispersed Golgi membranes. EtOH-activated autophagic flux is evident through increased WIPI2 recruitment to the Golgi, phagophore formation, enhanced LC3B lipidation, and reduced SQSTM1/p62. Although GOLGA4 dimerization and intra-Golgi localization are unaffected, loss of RAB3D leads to an extension of the cytoplasmic N terminal domain of GOLGA4, forming GOLGA4-positive phagophores. Autophagy inhibition by hydroxychloroquine (HCQ) prevents alcohol-mediated Golgi disorganization, restores distribution of ASGR (asialoglycoprotein receptor), and mitigates COL (collagen) deposition and steatosis. In contrast to short-term exposure to HCQ, extended co-treatment with both EtOH and HCQ results in the depletion of LC3B protein via proteasomal degradation. Thus, (a) RAB3D deficiency and GOLGA4 conformational changes are pivotal in MYH9-driven, EtOH-mediated Golgiphagy, and (b) HCQ treatment holds promise as a therapeutic approach for alcohol-induced liver injury.Abbreviation: ACTB: actin, beta; ALD: alcohol-associated liver disease; ASGR: asialoglycoprotein receptor; AV: autophagic vacuoles; EM: electron microscopy; ER: endoplasmic reticulum; EtOH: ethanol; HCQ: hydroxychloroquine; IP: immunoprecipitation; KD: knockdown; KO: knockout; MYH10/NMIIB: myosin, heavy polypeptide 10, non-muscle; MYH9/NMIIA: myosin, heavy polypeptide 9, non-muscle; PLA: proximity ligation assay; ORO: Oil Red O staining; PM: plasma membrane; TGN: trans-Golgi network; SIM: structured illumination super-resolution microscopy.

Pleiotropic effects of Salacia reticulata and Simvastatin on oxidative stress and insulin resistance in a rat model.

BACKGROUND: The present study investigated the effects of Salacia reticulata and simvastatin on oxidative stress and insulin resistance in Sprague-Dawley (SD) rats. We compared the protective effect of a methanolic extract of Salacia reticulata (SR) with simvastatin (SVS) in rats fed a high-fat diet (HFD). METHODS AND RESULTS: Male Sprague-Dawley rats were divided into the following five different groups: control (C), C+SR, HFD, HFD+SR, and HFD+SVS. High-fat diet fed rats showed hyperglycemia, hyperinsulinemia, hyperleptinemia, dyslipidemia, and hypoadiponectinemia after 90 days. Treatment of high-fat diet fed rats with SR/SVS significantly (p < 0.05) reduced high-fat diet induced increases in plasma triglycerides, total cholesterol, very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and decreased high- density lipoprotein (HDL) accompanied by an increase in lipid peroxidation (LPO) and protein oxidation. In addition, a significant decrease in the activities of antioxidant enzymes and enzymes of the polyol pathway was observed in rats fed high-fat diet. SR was found to be more effective than SVS. Moreover, infiltration of inflammatory cells and fibrosis in the liver of high-fat diet fed rats by SR/SVS were also prevented. CONCLUSIONS: The present study confirms that SR/SVS may be a new and promising remedial approach because of its beneficial effects on the pathophysiological processes of obesity and related metabolic disorders.

Glucagon-like peptide 1 receptor agonist, exendin-4, reduces alcohol-associated fatty liver disease.

Fatty liver is the earliest response to excessive ethanol consumption, which increases the susceptibility of the liver to develop advanced stage of liver disease. Our previous studies have revealed that chronic alcohol administration alters metabolic hormone levels and their functions. Of current interest to our laboratory is glucagon-like peptide 1 (GLP-1), a widely studied hormone known to reduce insulin resistance and hepatic fat accumulation in patients with metabolic-associated fatty liver disease. In this study, we examined the beneficial effects of exendin-4 (a GLP-1 receptor agonist) in an experimental rat model of ALD. Male Wistar rats were pair-fed the Lieber-DeCarli control or ethanol diet. After 4 weeks of this feeding regimen, a subset of rats in each group were intraperitoneally injected every other day with either saline or exendin-4 at a dose of 3 nmol/kg/day (total 13 doses) while still being fed their respective diet. At the end of the treatment, rats were fasted for 6 h and glucose tolerance test was conducted. The following day, the rats were euthanized, and the blood and tissue samples collected for subsequent analysis. We found that exendin-4 treatment had no significant effect on body weight gain among the experimental groups. Exendin-4-treated ethanol rats exhibited improved alcohol-induced alterations in liver/body weight and adipose/body weight ratio, serum ALT, NEFA, insulin, adiponectin and hepatic triglyceride levels. Reduction in indices of hepatic steatosis in exendin-4 treated ethanol-fed rats was attributed to improved insulin signaling and fat metabolism. These results strongly suggest that exendin-4 mitigates alcohol-associated hepatic steatosis by regulating fat metabolism.

Beneficiary effect of Commiphora mukul ethanolic extract against high fructose diet induced abnormalities in carbohydrate and lipid metabolism in wistar rats.

The present study was proposed to elucidate the effect of Commiphora mukul gum resin elthanolic extract treatment on alterations in carbohydrate and lipid metabolisms in rats fed with high-fructose diet. Male Wistar rats were divided into four groups: two of these groups (group C and C+CM) were fed with standard pellet diet and the other two groups (group F and F+CM) were fed with high fructose (66 %) diet. C. mukul suspension in 5% Tween-80 in distilled water (200 mg/kg body weight/day) was administered orally to group C+CM and group F+CM. At the end of 60-day experimental period, biochemical parameters related to carbohydrate and lipid metabolisms were assayed. C. mukul treatment completely prevented the fructose-induced increased body weight, hyperglycemia, and hypertriglyceridemia. Hyperinsulinemia and insulin resistance observed in group F decreased significantly with C. mukul treatment in group F+CM. The alterations observed in the activities of enzymes of carbohydrate and lipid metabolisms and contents of hepatic tissue lipids in group F rats were significantly restored to near normal values by C. mukul treatment in group F+CM. In conclusion, our study demonstrated that C. mukul treatment is effective in preventing fructose-induced insulin resistance and hypertriglyceridemia while attenuating the fructose induced alterations in carbohydrate and lipid metabolisms by the extract which was further supported by histopathological results from liver samples which showed regeneration of the hepatocytes. This study suggests that the plant can be used as an adjuvant for the prevention and/or management of insulin resistance and disorders related to it.

Protective effect of Caralluma fimbriata against high-fat diet induced testicular oxidative stress in rats.

High-fat diet (HFD) promotes the oxidative stress formation, which in turn has hazardous effects on reproductive system and fertility. The objective of this study was to evaluate the protective effect of Caralluma fimbriata on high-fat diet-induced oxidative stress in the testis of rat. Male Wistar rats were randomly divided into five groups: Control (C), Control treated with CFE (C+ CFE), High fat diet fed (HFD), High fat diet fed treated with CFE (HFD+CFE) and High fat diet fed treated with Metformin (HFD+Met). CFE was orally administered (200mg/kg body weight) for 90days to groups-C+CFE and HFD+CFE rats. The effects of HF-diet on the reproductive organs were determined by measuring relative and absolute testes and epididymal fat pads weights. Regarding testes antioxidant status, high-fat fed rats showed higher levels of lipid peroxidation, protein oxidation, polyol pathway enzymes and lower GSH levels and lower activities of antioxidants, while CFE treatment prevented all these observed abnormalities. The present study clearly indicates that CFE offers a significant protection against HF-diet induced testicular oxidative stress in rats.

Abnormalities in carbohydrate and lipid metabolisms in high-fructose dietfed insulin-resistant rats: amelioration by Catharanthus roseus treatments.

High intake of dietary fructose has been shown to exert a number of adverse metabolic effects in humans and experimental animals. The present study was proposed to elucidate the effect of Catharanthus roseus (C. roseus) leaf powder treatment on alterations in carbohydrate and lipid metabolisms in rats fed with high-fructose diet. Male Wistar rats of body weight around 180 g were divided into four groups, two of these groups (groups C and C+CR) were fed with standard pellet diet and the other two groups (groups F and F+CR) were fed with high-fructose (66 %) diet. C. roseus leaf powder suspension in water (100 mg/kg body weight/day) was administered orally to group C+CR and group F+CR. At the end of a 60-day experimental period, biochemical parameters related to carbohydrate and lipid metabolisms were assayed. C. roseus treatment completely prevented the fructose-induced increased body weight, hyperglycemia, and hypertriglyceridemia. Hyperinsulinemia and insulin resistance observed in group F was significantly decreased with C. roseus treatment in group F+CR. The alterations observed in the activities of enzymes of carbohydrate and lipid metabolisms and contents of hepatic tissue lipids in group F rats were significantly restored to near normal values by C. roseus treatment in group F+CR. In conclusion, our study demonstrates that C. roseus treatment is effective in preventing fructose-induced insulin resistance and hypertriglyceridemia while attenuating the fructose-induced alterations in carbohydrate and lipid metabolisms. This study suggests that the plant can be used as an adjuvant for the prevention and/or management of insulin resistance and disorders related to it.

Antihyperglycemic and antioxidant activities of alcoholic extract of Commiphora mukul gum resin in streptozotocin induced diabetic rats.

BACKGROUND AND OBJECTIVES: The present study investigated the effect of Commiphora mukul ethanol extract gum resin (CMEEt) on streptozotocin (STZ) induced diabetic rats by measuring fasting blood glucose, plasma insulin, plasma lipid profile, atherogenic index, hepatic lipid peroxidation (LPO), protein oxidation (PO) and activities of enzymatic antioxidants. METHODS: Wistar albino rats were divided into 4 groups, normal control group, CM-treated control group, diabetic control group and CM-treated diabetic group. For induction of diabetes, STZ was administered at a dose of 55mg/kg body weight, meanwhile CM-treated groups were administered CMEEt at a dose of 200mg/kg body weight for 60 days. Body weight, plasma glucose and insulin levels were determined in different experimental days, after end of the experimental period the plasma lipid profile and antioxidant enzymes were determined in hepatic tissue. RESULTS: Increase in plasma glucose, total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), hepatic LPO and PO levels with decrease in plasma high density lipoprotein cholesterol (HDL-C), insulin, hepatic reduced glutathione (GSH) content and activities of antioxidant enzymes namely, glutathione peroxidase (GPX), glutathione reductase (GR), glutathione-S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) were the salient features observed in diabetic rats. On the other hand, oral administration of CMEEt at a dose of 200mg/kg for 60 days resulted in the prevention of above mentioned abnormalities. CONCLUSION: The results suggest that CMEEt could be beneficial in the treatment of diabetes, characterized by atherogenous lipoprotein profile, aggravated antioxidant status and impaired glucose metabolism and in their prevention.

Antihyperglycemic activity of Catharanthus roseus leaf powder in streptozotocin-induced diabetic rats.

Catharanthus roseus Linn (Apocynaceae), is a traditional medicinal plant used to control diabetes, in various regions of the world. In this study we evaluated the possible antidiabetic and hypolipidemic effect of C. roseus (Catharanthus roseus) leaf powder in diabetic rats. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ, 55 mg/kg body wt) to male Wistar rats. The animals were divided into four groups: Control, control-treated, diabetic, and diabetic-treated group. Diabetic-treated and control-treated rats were treated with C. roseus leaf powder suspension in 2 ml distilled water, orally (100 mg/kg body weight/day/60 days). In diabetic rats (D-group) the plasma glucose was increased and the plasma insulin was decreased gradually. In the diabetic-treated group lowering of plasma glucose and an increase in plasma insulin were observed after 15 days and by the end of the experimental period the plasma glucose had almost reached the normal level, but insulin had not. The significant enhancement in plasma total cholesterol, triglycerides, LDL and VLDL-cholesterol, and the atherogenic index of diabetic rats were normalized in diabetic-treated rats. Decreased hepatic and muscle glycogen content and alterations in the activities of enzymes of glucose metabolism (glycogen phosphorylase, hexokinase, phosphofructokinase, pyruvate kinase, and glucose-6-phosphate dehydrogenase), as observed in the diabetic control rats, were prevented with C. roseus administration. Our results demonstrated that C. roseus with its antidiabetic and hypolipidemic properties could be a potential herbal medicine in treating diabetes.