Effect of vitamins A, E, C and omega-3 fatty acids supplementation on the level of catalase and superoxide dismutase activities in streptozotocin-induced diabetic rats

Integrated traditional Chinese and Western medicine in the prevention and treatment of non-alcoholic fatty liver disease: future directions and strategies

Traditional Chinese medicine (TCM) has been widely used for several centuries for metabolic diseases, including non-alcoholic fatty liver disease (NAFLD). At present, NAFLD has become the most prevalent form of chronic liver disease worldwide and can progress to non-alcoholic steatohepatitis (NASH), cirrhosis, and even hepatocellular carcinoma. However, there is still a lack of effective treatment strategies in Western medicine. The development of NAFLD is driven by multiple mechanisms, including genetic factors, insulin resistance, lipotoxicity, mitochondrial dysfunction, endoplasmic reticulum stress, inflammation, gut microbiota dysbiosis, and adipose tissue dysfunction. Currently, certain drugs, including insulin sensitizers, statins, vitamin E, ursodeoxycholic acid and betaine, are proven to be beneficial for the clinical treatment of NAFLD. Due to its complex pathogenesis, personalized medicine that integrates various mechanisms may provide better benefits to patients with NAFLD. The holistic view and syndrome differentiation of TCM have advantages in treating NAFLD, which are similar to the principles of personalized medicine. In TCM, NAFLD is primarily classified into five types based on clinical experience. It is located in the liver and is closely related to spleen and kidney functions. However, due to the multi-component characteristics of traditional Chinese medicine, its application in the treatment of NAFLD has been considerably limited. In this review, we summarize the advances in the pathogenesis and treatment of NAFLD, drawn from both the Western medicine and TCM perspectives. We highlight that Chinese and Western medicine have complementary advantages and should receive increased attention in the prevention and treatment of NAFLD.

Nicotinamide prevention in diabetes-induced alterations in the rat liver

Objective. The study was performed to elucidate whether nicotinamide (NAm) can attenuate the diabetes-induced liver damage by correction of ammonia detoxifying function and disbalance of NAD-dependent processes in diabetic rats. Methods. After four weeks of streptozotocin-induced diabetes, Wistar male rats were treated for two weeks with or without NAm. Urea concentration, arginase, and glutamine synthetase activities, NAD+ levels, and NAD+/NADH ratio were measured in cytosolic liver extracts. Expression of parp-1 gene in the liver was estimated by quantitative polymerase chain reaction and PARP-1 cleavage evaluated by Western blotting. Results. Despite the blood plasma lipid peroxidation products in diabetic rats were increased by 60%, the activity of superoxide dismutase (SOD) was reduced. NAm attenuated the oxidative stress, but did not affect the enzyme activity in diabetic rats. In liver of the diabetic rats, urea concentration and arginase activity were significantly higher than in the controls. The glutamine synthetase activity was decreased. Decline in NAD+ level and cytosolic NAD+/NADH ratio in the liver of diabetic rats was observed. Western blot analysis demonstrated a significant up-regulation of PARP-1 expression accompanied by the enzyme cleavage in the diabetic rat liver. However, no correlation was seen between mRNA expression of parp-1 gene and PARP-1 protein in the liver of diabetic rats. NAm markedly attenuated PARP-1 cleavage induced by diabetes, but did not affect the parp-1 gene expression. Conclusions. NAm counteracts diabetes-induced impairments in the rat liver through improvement of its detoxifying function, partial restoration of oxidative stress, NAD+ level, normalization of redox state of free cytosolic NAD+/NADH-couples, and prevention of PARP-1 cleavage.

Therapeutic mechanisms and beneficial effects of non-antidiabetic drugs in chronic liver diseases

The global burden of chronic liver disease (CLD) is substantial. Due to the limited indication of and accessibility to antiviral therapy in viral hepatitis and lack of effective pharmacological treatment in nonalcoholic fatty liver disease, the beneficial effects of antidiabetics and non-antidiabetics in clinical practice have been continuously investigated in patients with CLD. In this narrative review, we focused on non-antidiabetic drugs, including ursodeoxycholic acid, silymarin, dimethyl4,4'-dimethoxy-5,6,5',6'-dimethylenedixoybiphenyl-2,2'-dicarboxylate, L-ornithine L-aspartate, branched chain amino acids, statin, probiotics, vitamin E, and aspirin, and summarized their beneficial effects in CLD. Based on the antioxidant, anti-inflammatory properties, and regulatory functions in glucose or lipid metabolism, several non-antidiabetic drugs have shown beneficial effects in improving liver histology, aminotransferase level, and metabolic parameters and reducing risks of hepatocellular carcinoma and mortality, without significant safety concerns, in patients with CLD. Although the effect as the centerpiece management in patients with CLD is not robust, the use of these non-antidiabetic drugs might be potentially beneficial as an adjuvant or combined treatment strategy.

Role of Food Antioxidants in Modulating Gut Microbial Communities: Novel Understandings in Intestinal Oxidative Stress Damage and Their Impact on Host Health

Dietary components have an important role on the structure and function of host gut microbial communities. Even though, various dietary components, such as carbohydrates, fats, proteins, fibers, and vitamins, have been studied in depth for their effect on gut microbiomes, little attention has been paid regarding the impact of several food antioxidants on the gut microbiome. The long-term exposure to reactive oxygen species (ROS) can cause microbial dysbiosis which leads to numerous intestinal diseases such as microbiota dysbiosis, intestinal injury, colorectal cancers, enteric infections, and inflammatory bowel diseases. Recently, it has been shown that the food derived antioxidant compounds might protect the host from intestinal oxidative stress via modulating the composition of beneficial microbial species in the gut. The present review summarizes the impact of food antioxidants including antioxidant vitamins, dietary polyphenols, carotenoids, and bioactive peptides on the structure as well as function of host gut microbial communities. Several in vitro, animal model, and clinical studies indicates that food antioxidants might modify the host gut microbial communities and their health status. However, still further clarification is needed as to whether changes in certain microbial species caused by food additives may lead to changes in metabolism and immune function.

Vitamins and non-alcoholic fatty liver disease: A Molecular Insight⋆

The incidence of non-alcoholic fatty liver disease (NAFLD) is rising rapidly across the globe. NAFLD pathogenesis is largely driven by an imbalance in hepatic energy metabolism and at present, there is no approved drug for its treatment. The liver plays a crucial role in micronutrient metabolism and deregulation of this micronutrient metabolism may contribute to the pathogenesis of NAFLD. Vitamins regulate several enzymatic processes in the liver, and derangement in vitamin metabolism is believed to play a critical role in NAFLD progression. The anti-oxidant activities of vitamin C and E have been attributed to mitigate hepatocyte injury, and alterations in the serum levels of vitamin D, vitamin B12 and folate have shown a strong correlation with NAFLD severity. This review aims to highlight the role of these vitamins, which represent promising therapeutic targets for the management of NAFLD.

Natural and synthetic antioxidants targeting cardiac oxidative stress and redox signaling in cardiometabolic diseases

Cardiometabolic diseases (CMDs) are metabolic diseases (e.g., obesity, diabetes, atherosclerosis, rare genetic metabolic diseases, etc.) associated with cardiac pathologies. Pathophysiology of most CMDs involves increased production of reactive oxygen species and impaired antioxidant defense systems, resulting in cardiac oxidative stress (OxS). To alleviate OxS, various antioxidants have been investigated in several diseases with conflicting results. Here we review the effect of CMDs on cardiac redox homeostasis, the role of OxS in cardiac pathologies, as well as experimental and clinical data on the therapeutic potential of natural antioxidants (including resveratrol, quercetin, curcumin, vitamins A, C, and E, coenzyme Q10, etc.), synthetic antioxidants (including N-acetylcysteine, SOD mimetics, mitoTEMPO, SkQ1, etc.), and promoters of antioxidant enzymes in CMDs. As no antioxidant indicated for the prevention and/or treatment of CMDs has reached the market despite the large number of preclinical and clinical studies, a sizeable translational gap is evident in this field. Thus, we also highlight potential underlying factors that may contribute to the failure of translation of antioxidant therapies in CMDs.

Ameliorative effect of combined low dose of Pioglitazone and omega-3 on spermatogenesis and steroidogenesis in diabetic rats

BACKGROUND

Chronic hyperglycemia is linked to either subfertility or infertility among diabetic males. Pioglitazone is one of the thiazolidinediones (TZDs) drugs that are selective peroxisome proliferator-activated receptor (PPAR-γ agonists used for treating type 2 diabetes mellitus (T2DM).

AIM

This study aims to explore the possible effect of low Pioglitazone dose and omega (ω-3) on rat male reproductive function. Furthermore, we evaluated the add-on effect of combined use of low Pioglitazone dose of and ω-3 on reproductive functions in adult male T2DM rats.

METHODS

Fifty adult male rats were included and subdivided into control and four test subgroups. T2DM was induced in test groups and subdivided into non-treated T2DM, ω-3 treated, 0.6 mg/kg Pioglitazone treated, and combined treated group (orally by gavage). Following 16 weeks, final body weight, testicular weight, fasting plasma glucose, and serum testosterone levels were measured. Semen analysis, testicular testosterone, malondialdehyde (MDA) concentrations, superoxide dismutase (SOD) activity, immunohistochemistry staining for apoptosis marker B-cell lymphoma protein 2 (Bcl-2), proliferation marker as proliferating cell nuclear antigen (PCNA), estrogen receptor α (ERα), androgen receptor (AR) were determined. Caspase-3, nuclear factor-kappa B (NF-kB), glucose transporter 3 (GLUT3), 17β-hydroxysteroid dehydrogenases (17β-HSD) PPARγ, and PPARα genes expression were analyzed by real-time polymerase chain reaction (RT-PCR).

RESULTS

Our findings revealed that treatment with low dose of Pioglitazone or ω-3 significantly lowered fasting plasma glucose and MDA levels, ameliorated diabetes effects on histological damage, improved antioxidant activity (SOD), significantly improved anti-apoptosis BCL-2 and proliferation (PCNA), remarkably elevated ERα, AR, 17β-HSD PPARγ, and PPARα expression with significant reduction in caspase-3, NF-kB genes expression and improved semen quality as well. Combined use of low dose of and ω-3 has better effects on all measured parameters.

CONCLUSION

Small Pioglitazone dose and ω-3 possess beneficial effects on spermatogenic and steroidogenic functions in adult diabetic rat; while combined use of both has an add-on effect.

The Role of Vitamin E in the Treatment of NAFLD

There has been a growing interest in the role of vitamin E supplementation in the treatment and/or prevention of nonalcoholic fatty liver (NAFLD). We performed a systematic review of the medical literature from inception through 15 June 2018 by utilizing PubMed and searching for key terms such as NAFLD, vitamin E, alpha-tocopherol, and nonalcoholic steatohepatitis (NASH). Data from studies and medical literature focusing on the role of vitamin E therapy in patients with NAFLD and nonalcoholic steatohepatitis (NASH) were reviewed. Most studies assessing the impact of vitamin E in NAFLD were designed to evaluate patients with NASH with documented biochemical and histological abnormalities. These studies demonstrated improvement in biochemical profiles, with a decline in or normalization of liver enzymes. Furthermore, histological assessment showed favorable outcomes in lobular inflammation and hepatic steatosis following treatment with vitamin E. Current guidelines regarding the use of vitamin E in the setting of NAFLD recommend that vitamin E-based treatment be restricted to biopsy-proven nondiabetic patients with NASH only. However, some concerns have been raised regarding the use of vitamin E in patients with NASH due to its adverse effects profile and lack of significant improvement in hepatic fibrosis. In conclusion, the antioxidant, anti-inflammatory, and anti-apoptotic properties of vitamin E accompanied by ease-of-use and exceptional tolerability have made vitamin E a pragmatic therapeutic choice in non-diabetic patients with histologic evidence of NASH. Future clinical trials with study design to assess vitamin E in combination with other anti-fibrotic agents may yield an additive or synergistic therapeutic effect.

α-Linolenic acid and exercise training independently, and additively, decrease blood pressure and prevent diastolic dysfunction in obese Zucker rats

KEY POINTS

α-linolenic acid (ALA) and exercise training both attenuate hyperlipidaemia-related cardiovascular derangements, however, there is a paucity of information pertaining to their mechanisms of action when combined. We investigated both the independent and combined effects of exercise training and ALA consumption in obese Zucker rats, aiming to determine the potential for additive improvements in cardiovascular function. ALA and exercise training independently improved cardiac output, end-diastolic volume, left ventricular fibrosis and mean blood pressure following a 4 week intervention. Combining ALA and endurance exercise yielded greater improvements in these parameters, independent of changes in markers of oxidative stress or endogenous anti-oxidants. We postulate that divergent mechanisms of action may explain these changes: ALA increases peripheral vasodilation, and exercise training stimulates angiogenesis.

ABSTRACT

Although α-linolenic acid (ALA) and endurance exercise training independently attenuate hyperlipidaemia-related cardiovascular derangements, there is a paucity of information pertaining to their mechanisms of action and efficacy when combined as a preventative therapeutic approach. Therefore, we used obese Zucker rats to investigate the independent and combined effects of these interventions on cardiovascular disease. Specifically, animals were randomly assigned to one of the following groups: control diet-sedentary, ALA supplemented-sedentary, control diet-exercise trained or ALA supplemented-exercise trained. Following a 4 week intervention, although the independent and combined effects of ALA and exercise reduced (P < 0.05) the serum free/esterified cholesterol ratio, only the ALA supplemented-exercise trained animals displayed a reduction in the content of both serum free and esterified cholesterol. Moreover, although ALA and endurance training individually increased cardiac output, stroke volume and end-diastolic volume, as well as reduced left ventricle fibrosis, mean blood pressure and total peripheral resistance, these responses were all greater following the combined intervention (ALA supplemented-exercise trained). These effects occurred independent of changes in oxidative phosphorylation proteins, markers of oxidative stress or endogenous anti-oxidant capacity. We propose that the beneficial effects of a combined intervention occur as a result of divergent mechanisms of action elicited by ALA and endurance exercise because only exercise training increased the capillary content in the left ventricle and skeletal muscle, and tended to decrease protein carbonylation in the left ventricle (P = 0.06). Taken together, our data indicate that combining ALA and endurance exercise provides additional improvements in cardiovascular disease risk reduction compared to singular interventions in the obese Zucker rat.

Embryo-fetal development toxicity of honokiol microemulsion intravenously administered to pregnant rats

The aim of this study was to evaluate the embryo-fetal development toxicity of honokiol microemulsion. The drug was intravenously injected to pregnant SD rats at dose levels of 0, 200, 600 and 2000 μg/kg/day from day 6-15 of gestation. All the pregnant animals were observed for body weights and any abnormal changes and subjected to caesarean-section on gestation day (GD) 20; all fetuses obtained from caesarean-section were assessed by external inspection, visceral and skeletal examinations. No treatment-related external alterations as well as visceral and skeletal malformations were observed in honokiol microemulsion groups. There was no significant difference in the body weight gain of the pregnant rats, average number of corpora lutea, and the gravid uterus weight in the honokiol microemulsion groups compared with the vehicle control group. However, at a dose level of 2000 μg/kg/day, there was embryo-fetal developmental toxicity observed, including a decrease in the body length and tail length of fetuses. In conclusion, the no-observed-adverse-effect level (NOAEL) of honokiol microemulsion is 600 μg/kg/day, 75 times above the therapeutic dosage and it has embryo-fetal toxicity at a dose level of 2000 μg/kg/day, which is approximately 250 times above the therapeutic dosage.