Therapeutic Effects of Heterotrigona itama (Stingless Bee) Bee Bread in Improving Hepatic Lipid Metabolism through theActivation of the Keap1/Nrf2 Signaling Pathway in an Obese Rat Model

Stimulation of auricular vagus nerve ameliorates chronic stress induced metabolic syndrome via activation of Sirtuin-6

Chronic stress is one of the potential causes of the progression of metabolic syndrome (MS). Chronic stress decreases the release of Sirtuin-6 (SIRT6), which regulates MS by controlling glucose, insulin, lipids, and hypertension. Vagus nerve stimulation (VNS) activates SIRT6 via the cholinergic anti-inflammatory pathway (CAP). However, the effectiveness of VNS therapy for treating MS induced by chronic stress has not yet been studied. In this study, we first validated a rat model of chronic unpredictable stress (CUS) and assessed the characteristic features of MS. The CUS rats were exposed to random stressors daily for 8 weeks. The stress response was then confirmed by behavioral alteration and elevated serum corticosterone levels in rats, as measured by various behavioral tests and an ELISA kit, respectively. The MS characteristics in CUS rats were assessed using measurements of fasting blood glucose (FBG), systolic blood pressure (SBP), lipid indices, insulin levels, and HOMA-IR. The stressed animals demonstrated a rise in FBG, SBP, and insulin along with altered lipid indices. After CUS, the rats were treated with VNS (6 Hz, 1.0 ms, 6 V, for 40 min × 14 days, alternatively), and their metabolic activity and vagal flow were assessed. Moreover, SIRT6 and AMP-activated protein kinase (AMPK) expression in rats was also assessed by immunohistochemistry and mRNA expression of liver and pancreatic tissue. SIRT6 and AMPK expression was decreased in CUS animals. Interestingly, VNS treatment attenuated CUS induced MS-associated parameters. These results indicate that VNS may be a beneficial complementary and non-pharmacological method for managing CUS-associated MS.

Bee bread shows therapeutic and protective effects by alleviating inflammation, oxidative stress, and apoptosis on acetic acid-induced gastric ulcer in rats

OBJECTIVE

This study investigated bee bread's (BB) protective and therapeutic effects on acetic acid-(AA)-induced gastric ulcers via oxidative stress, DNA damage, inflammation, and apoptosis.

MATERIALS AND METHODS

Rats were administered saline-(1ml) or BB-(0.5g/kg/day;1ml) by oral gavage once daily for 10-day following 80% AA-induced chronic ulceration in treatment group. Pretreatment group received saline or BB for 10-day before and 3-day after ulcer induction. Stomachs of decapitated rats were collected for ulcer index, histological and biochemical analyses.

RESULTS

BB significantly reduced the gastric ulcer index and levels of chemiluminescence, HMGB-1, IL-6, IL-1ß and IL-8 levels in pretreatment and treatment groups. In BB-pretreated ulcer group, MPO-(saline\BB, 39.9±3.7 U/g;22.2±2.2 U/g), caspase-3 (0.40±0.07 ng/g;0.18±0.01 ng/g) and IFN-γ (15.46±1.76;9.51±1.95 ng/g) levels decreased and TNF-α (31.77±5.13;18.94±2.59 ng/g) reduced only in BB-treated ulcer group. MDA, GSH, NRF-2, and 8-OHdG levels remained unchanged.

CONCLUSION

BB has demonstrated protective and therapeutic effects by reducing ROS production, modulating inflammation and apoptosis.

Examining the Pathogenesis of MAFLD and the Medicinal Properties of Natural Products from a Metabolic Perspective

Metabolic-associated fatty liver disease (MAFLD), characterized primarily by hepatic steatosis, has become the most prevalent liver disease worldwide, affecting approximately two-fifths of the global population. The pathogenesis of MAFLD is extremely complex, and to date, there are no approved therapeutic drugs for clinical use. Considerable evidence indicates that various metabolic disorders play a pivotal role in the progression of MAFLD, including lipids, carbohydrates, amino acids, and micronutrients. In recent years, the medicinal properties of natural products have attracted widespread attention, and numerous studies have reported their efficacy in ameliorating metabolic disorders and subsequently alleviating MAFLD. This review aims to summarize the metabolic-associated pathological mechanisms of MAFLD, as well as the natural products that regulate metabolic pathways to alleviate MAFLD.

Ramon Flour (Brosimum alicastrum Swartz) Ameliorates Hepatic Lipid Accumulation, Induction of AMPK Phosphorylation, and Expression of the Hepatic Antioxidant System in a High-Fat-Diet-Induced Obesity Mouse Model

Excessive consumption of fat and carbohydrates, together with a decrease in traditional food intake, has been related to obesity and the development of metabolic alterations. Ramon seed is a traditional Mayan food used to obtain Ramon flour (RF) with high biological value in terms of protein, fiber, micronutrients, and bioactive compounds such as polyphenols. However, few studies have evaluated the beneficial effects of RF. Thus, we aimed to determine the metabolic effects of RF consumption on a high-fat-diet-induced obesity mouse model. We divided male BALB/c mice into four groups (n = 5 each group) and fed them for 90 days with the following diets: Control (C): control diet (AIN-93), C + RF: control diet adjusted with 25% RF, HFD: high-fat diet + 5% sugar in water, and HFD + RF: high-fat diet adjusted with 25% RF + 5% sugar in water. The RF prevented the increase in serum total cholesterol (TC) and alanine transaminase (ALT) that occurred in the C and HFD groups. Notably, RF together with HFD increased serum polyphenols and antioxidant activity, and it promoted a decrease in the adipocyte size in white adipose tissue, along with lower hepatic lipid accumulation than in the HFD group. In the liver, the HFD + RF group showed an increase in the expression of β-oxidation-related genes, and downregulation of the fatty acid synthase (Fas) gene compared with the HFD group. Moreover, the HFD + RF group had increased hepatic phosphorylation of AMP-activated protein kinase (AMPK), along with increased nuclear factor erythroid 2-related factor 2 (NRF2) and superoxide dismutase 2 (SOD2) protein expression compared with the HFD group. Thus, RF may be used as a nutritional strategy to decrease metabolic alterations during obesity.

Saponins of Tomato Extract Improve Non-Alcoholic Fatty Liver Disease by Regulating Oxidative Stress and Lipid Homeostasis

The present study investigated the impact of saponins of tomato extract (STE) on non-alcoholic fatty liver disease (NAFLD). The findings demonstrated that introducing STE in NAFLD mice revealed promising results in ameliorating symptoms of oxidative stress, lipid metabolism disorders, visceral fat deposition and fatty liver disease. Moreover, the mechanistic studies have demonstrated that STE delivers its effects by activating adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), thereby suppressing downstream protein expression associated with fatty acid synthesis. In such conditions, lipid metabolism can be improved. Simultaneously, STE enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) and entry into the nucleus and initiated the transcription of downstream antioxidant factors, thereby relieving oxidative stress induced by a high-fat diet and lowering oxidative damage to the liver. Such results imply that the administration of STE can be regarded as a viable treatment option for NAFLD, providing a mechanism that can regulate the AMPK and Nrf2 signaling pathways.