Resveratrol reduces liver endoplasmic reticulum stress and improves insulin sensitivity in vivo and in vitro

Hydrolysable tannin improves growth performance and liver health of largemouth bass (Micropterus salmoides) fed high soybean meal diets

This study provided evidence that the inclusion of hydrolysable tannin (HT) in high soybean meal (SBM) diets improved growth performance and glycolipid metabolism of largemouth bass (Micropterus salmoides). In vivo, various levels of HT were added to high SBM diets and fed to largemouth bass (initial weight: 6.00 ± 0.03 g) for 56 days. Results showed that a high level of SBM led to the reduction in growth performance, as evidenced by decreased weight gain rate and impaired hepatic function. Dietary supplementation with HT (1.0 g/kg) improved growth performance of largemouth bass, accompanied by the enhancements in hepatic antioxidant capacity and glycolipid metabolism. In vitro, HT facilitated glucose utilization in hepatocytes and positively influenced the modulation of crucial genes within the PI3K/Akt signaling pathway. Conversely, administration of LY294002 (a PI3K inhibitor) reversed the detrimental effects observed in hepatocytes exposed to high glucose levels. Overall, incorporating HT (1.0 g/kg) into the diet enhanced liver health and improved the absorption and utilization of SBM in largemouth bass, potentially achieved through modulation of the PI3K/Akt signaling pathway.

Boosting wound healing in diabetic rats: The role of nicotinamide riboside and resveratrol in UPR modulation and pyroptosis inhibition

BACKGROUND

Diabetes-related skin ulcers provide a substantial therapeutic issue, sometimes leading to amputation, needing immediate practical treatments for efficient wound care. While the exact mechanisms are unknown, pyroptosis and deregulation of the unfolded protein response (UPR) are known to exacerbate inflammation. Nicotinamide Riboside (NR) and Resveratrol (RV), which are known for their Nicotinamide adenine dinucleotide (NAD+) boosting and anti-inflammatory properties, are being studied as potential treatments. The purpose of this study was to shed light on the underlying molecular mechanisms and explore the medical application of NR and RV in diabetic wound healing.

METHODS

54 male Sprague-Dawley rats divided into control, diabetic (DM), Gel Base, DM-NR, DM-RV, and DM-NR + RV. Rats were orally administered 50 mg/kg/day of RV and 300 mg/kg/day of NR for 5 weeks. Following diabetes induction, their wounds were topically treated with 5 % NR and RV gel for 15 days. The wound closure rate, body weight, and serum lipid profiles were examined. Gene expression study evaluated UPR and pyroptosis-related genes (BIP, PERK, ATF6, IRE1α, sXBP1, CHOP, NLRP3, caspase-1, NFκB, and IL1-β) in wound tissues, alongside histological assessment of cellular changes.

RESULTS

NR and RV treatments greatly enhanced wound healing. Molecular investigation demonstrated UPR and pyroptosis marker modifications, suggesting UPR balance and anti-inflammatory effects. Histological investigation demonstrated decreased inflammation and increased re-epithelialization. The combination of NR and RV therapy had better results than either treatment alone.

CONCLUSION

This study shows that NR and RV have therapeutic promise in treating diabetic wounds by addressing UPR dysregulation, and pyroptosis. The combination therapy is a viable strategy to improving the healing process, providing a multimodal intervention for diabetic skin ulcers. These findings pave the way for additional investigation and possible therapeutic applications, giving hope for better outcomes in diabetic wound care.

Resveratrol relieves HFD-induced insulin resistance in skeletal muscle tissue through antioxidant capacity enhancement and the Nrf2-Keap1 signaling pathway

BACKGROUND

Resveratrol has received much attention due to its beneficial effects including antioxidant activity. The purpose of this study was to investigate the therapeutic effects of resveratrol treatment on oxidative stress and insulin resistance in the skeletal muscle of high-fat diet (HFD)-fed animals.

METHODS AND RESULTS

A total of 30 six-week-old C57BL/6J mice were randomly allocated to three groups (10 animals in each group): The control group in which mice were fed a normal chow diet (NCD); the HFD group in which mice were fed an HFD for 26 weeks; and the HFD-resveratrol group in which HFD was replaced by a resveratrol supplemented-HFD (400 mg/kg diet) after 10 weeks of HFD feeding. At the end of this period, gastrocnemius muscle samples were examined to determine insulin resistance and the oxidative status in the presence of HFD and resveratrol. Resveratrol supplementation in HFD-fed mice reduced body and adipose tissue weight, improved insulin sensitivity, and decreased oxidative stress as indicated by lower malonaldehyde (MDA) levels and higher total antioxidant capacity. The supplement also increased the expression and activity of antioxidative enzymes in gastrocnemius muscle and modulated Nrf2 and Keap1 expression levels.

CONCLUSIONS

These results suggest that resveratrol is effective in improving the antioxidant defense system of the skeletal muscle in HFD-fed mice, indicating its therapeutic potential to combat diseases associated with insulin resistance and oxidative stress.

Association of exposure to multiple perfluoroalkyl and polyfluoroalkyl substances and glucose metabolism in National Health and Nutrition Examination Survey 2017-2018

Objective

To investigate the relationships between perfluoroalkyl and polyfluoroalkyl substances (PFASs) exposure and glucose metabolism indices.

Methods

Data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 waves were used. A total of 611 participants with information on serum PFASs (perfluorononanoic acid (PFNA); perfluorooctanoic acid (PFOA); perfluoroundecanoic acid (PFUA); perfluorohexane sulfonic acid (PFHxS); perfluorooctane sulfonates acid (PFOS); perfluorodecanoic acid (PFDeA)), glucose metabolism indices (fasting plasma glucose (FPG), homeostasis model assessment for insulin resistance (HOMA-IR) and insulin) as well as selected covariates were included. We used cluster analysis to categorize the participants into three exposure subgroups and compared glucose metabolism index levels between the subgroups. Least absolute shrinkage and selection operator (LASSO), multiple linear regression analysis and Bayesian kernel machine regression (BKMR) were used to assess the effects of single and mixed PFASs exposures and glucose metabolism.

Results

The cluster analysis results revealed overlapping exposure types among people with higher PFASs exposure. As the level of PFAS exposure increased, FPG level showed an upward linear trend (p < 0.001), whereas insulin levels demonstrated a downward linear trend (p = 0.012). LASSO and multiple linear regression analysis showed that PFNA and FPG had a positive relationship (>50 years-old group: β = 0.059, p < 0.001). PFOA, PFUA, and PFHxS (≤50 years-old group: insulin β = -0.194, p < 0.001, HOMA-IR β = -0.132, p = 0.020) showed negative correlation with HOMA-IR/insulin. PFNA (>50 years-old group: insulin β = 0.191, p = 0.018, HOMA-IR β = 0.220, p = 0.013) showed positive correlation with HOMA-IR/insulin, which was essentially the same as results that obtained for the univariate exposure-response map in the BKMR model. Association of exposure to PFASs on glucose metabolism indices showed positive interactions between PFOS and PFHxS and negative interactions between PFOA and PFNA/PFOS/PFHxS.

Conclusion

Our study provides evidence that positive and negative correlations between PFASs and FPG and HOMA-IR/insulin levels are observed, respectively. Combined effects and interactions between PFASs. Given the higher risk of glucose metabolism associated with elevated levels of PFAS, future studies are needed to explore the potential underlying mechanisms.

Integration of dietary nutrition and TRIB3 action into diabetes mellitus

Despite intensive studies for decades, the common mechanistic correlations among the underlying pathology of diabetes mellitus (DM), its complications, and effective clinical treatments remain poorly characterized. High-quality diets and nutrition therapy have played an indispensable role in the management of DM. More importantly, tribbles homolog 3 (TRIB3), a nutrient-sensing and glucose-responsive regulator, might be an important stress-regulatory switch, linking glucose homeostasis and insulin resistance. Therefore, this review aimed to introduce the latest research progress on the crosstalk between dietary nutrition intervention and TRIB3 in the development and treatment of DM. This study also summarized the possible mechanisms involved in the signaling pathways of TRIB3 action in DM, in order to gain an in-depth understanding of dietary nutrition intervention and TRIB3 in the pathogenesis of DM at the organism level.

Hepatoprotective Activity and Mechanisms of Prenylated Stilbenoids

Dietary prenylated stilbenoids, found in various food sources, offer multiple health benefits, including liver protection. However, the underlying mechanisms of hepatoprotection remain unclear. In this study, we synthesized 13 natural prenylated stilbenoids and examined their hepatoprotective activities, with silent mating type information regulation 2 homologue-1 (SIRT1) as the primary target for screening. Among all of the prenylated stilbenoids tested, 4-C-geranyl oxyresveratrol demonstrated superior performance. It activated SIRT1 activity more effectively than resveratrol, a well-known SIRT1 activator. To further investigate the mechanism of liver protection, two in vitro models were used: the palmitic acid-induced lipid accumulation model and the H2O2-induced apoptosis model. Our findings suggested that 4-C-geranyl oxyresveratrol mitigated lipid accumulation through the SIRT1-PGC1α pathway, reduced apoptosis via the SIRT1-p53-p21 pathway, and exerted antioxidant effects through the SIRT1-Nrf2 pathway. These findings provide new insights into the chemical basis of the health benefits of prenylated stilbenoids and their potential use as functional food additives.

An AMP Kinase-pathway dependent integrated stress response regulates ageing and longevity

The purpose of this article is to investigate the role of the AMP-kinase pathway (AMPK pathway) in the induction of a concomitant set of health benefits by exercise, numerous drugs, and health ingredients, all of which are adversely affected by ageing. Despite the AMPK pathway being frequently mentioned in relation to both these health effects and ageing, it appears challenging to understand how the activation of a single biochemical pathway by various treatments can produce such a diverse range of concurrent health benefits, involving so many organs. We discovered that the AMPK pathway functions as an integrated stress response system because of the presence of a feedback loop in it. This evolutionary conserved stress response system detects changes in AMP/ATP and NAD/NADH ratios, as well as the presence of potential toxins, and responds by activating a common protective transcriptional response that protects against aging and promotes longevity. The inactivation of the AMPK pathway with age most likely explains why ageing has a negative impact on the above-mentioned set of health benefits. We conclude that the presence of a feedback loop in the AMP-kinase pathway positions this pathway as an AMPK-ISR (AMP Kinase-dependent integrated stress response) system that responds to almost any type of (moderate) environmental stress by inducing various age-related health benefits and longevity.

Insulin: A connection between pancreatic β cells and the hypothalamus

Insulin is a hormone secreted by pancreatic β cells. The concentration of glucose in circulation is proportional to the secretion of insulin by these cells. In target cells, insulin binds to its receptors and activates phosphatidylinositol-3-kinase/protein kinase B, inducing different mechanisms depending on the cell type. In the liver it activates the synthesis of glycogen, in adipose tissue and muscle it allows the capture of glucose, and in the hypothalamus, it regulates thermogenesis and appetite. Defects in insulin function [insulin resistance (IR)] are related to the development of neurodegenerative diseases in obese people. Furthermore, in obesity and diabetes, its role as an anorexigenic hormone in the hypothalamus is diminished during IR. Therefore, hyperphagia prevails, which aggravates hyper-glycemia and IR further, becoming a vicious circle in which the patient cannot regulate their need to eat. Uncontrolled calorie intake induces an increase in reactive oxygen species, overcoming cellular antioxidant defenses (oxidative stress). Reactive oxygen species activate stress-sensitive kinases, such as c-Jun N-terminal kinase and p38 mitogen-activated protein kinase, that induce phos-phorylation in serine residues in the insulin receptor, which blocks the insulin signaling pathway, continuing the mechanism of IR. The brain and pancreas are organs mainly affected by oxidative stress. The use of drugs that regulate food intake and improve glucose metabolism is the conventional therapy to improve the quality of life of these patients. Currently, the use of antioxidants that regulate oxidative stress has given good results because they reduce oxidative stress and inflammatory processes, and they also have fewer side effects than synthetic drugs.

Resveratrol suppresses lipopolysaccharide-mediated activation of osteoclast precursor RAW 264.7 cells by increasing miR-181a-5p expression

Resveratrol (Res) has anti-inflammation and antiosteoporosis functions. We evaluated the effect of Res on osteoclast differentiation by releasing inflammatory cytokines from osteoclast precursor RAW 264.7 cells stimulated by lipopolysaccharide (LPS). In the study, LPS (1 ng/L) was used to induce the Raw 264.7 inflammatory injury model in vitro. A total of 25 ng/mL M-CSF + 30 ng/mL RANKL or plus 1 μg/L LPS was used to induce osteoclastogenesis in the experiments. We utilized the Cell Counting Kit-8 assay to measure the relative cell survival of RAW 264.7 cells. Then, enzyme-linked immunosorbent assays were utilized to measure the abundance of inflammatory markers, such as interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and IL-6. Subsequently, Western blot analysis was applied to assess the abundance of phosphorylated transforming growth factor beta-activated kinase 1 (P-TAK1) protein, TNF receptor-associated factor 6 (TRAF6), nuclear factor-κB inhibitor protein (IκB), phosphorylated IκB-α (P-IκB-α), and nuclear factor κB65 (NF-κB65). mRNA expression levels of miR-181a-5p, TRAF6, specific gene calcitonin receptor (CTR), activated T nuclear factor 1 (NFATC1), cathepsin K (CTSK), and matrix metalloproteinase (MMP)-9 were determined via a real-time polymerase chain reaction. Osteoclast bone resorption function was determined. Finally, tartrate-resistant acid phosphatase (TRAP) staining was performed.The results found that Compared with the model group, the degrees of expressions of supernatant inflammatory factors TNF-α, IL-1β, and IL-6 were substantially attenuated in the Res treatment group (p < 0.05). Furthermore, the extent of miR-181a-5p expression in the RAW 264.7 cells significantly increased, whereas P-IκB-α, P-TAK1, NF-κB65, and TRAF6 expressions significantly decreased in the Res treatment group as opposed to the model group (p < 0.05). The CTR, NFATC1, MMP-9, CTSK, and TRAP mRNA expression levels were substantially reduced during osteoclast differentiation and bone resorption in the Res treatment group.The results suggest that Res can reduce the RAW 264.7 cell differentiation into osteoclasts and relieve LPS-stimulated osteoporosis, and the underlying mechanism may be associated with the Res-inhibited activity of the TRAF6/TAK1 pathway through the increased miR-181a-5p expression.

Role of the AMPK/SIRT1 pathway in non‑alcoholic fatty liver disease (Review)

Non‑alcoholic fatty liver disease (NAFLD) is an increasingly prevalent ailment worldwide. Moreover, de novo lipogenesis (DNL) is considered a critical factor in the development of NAFLD; hence, its inhibition is a promising target for the prevention of fatty liver disease. There is evidence to indicate that AMP‑activated protein kinase (AMPK) and sirtuin 1 (SIRT1) may play a crucial role in DNL and are the regulatory proteins in type 2 diabetes mellitus, obesity and cardiovascular disease. Therefore, AMPK and SIRT1 may be promising targets for the treatment of NAFLD. The present review article thus aimed to summarize the findings of clinical studies published during the past decade that suggested the beneficial effects of AMPK and SIRT1, using their specific activators and their combined effects on fatty liver disease.

Resveratrol promotes liver cell survival in mice liver-induced ischemia-reperfusion through unfolded protein response: a possible approach in liver transplantation

Background

Ischemia-reperfusion (I/R) of the liver is a multifactorial condition that happens during transplantation and surgery. The deleterious effects of I/R result from the acute production of reactive oxygen species (ROS), which can trigger immediate tissue damage and induce a series of destructive cellular responses, including apoptosis organ failure and inflammation. The production of ROS in the I/R process can damage the antioxidant system and cause liver damage. Resveratrol has been shown to have antioxidant properties in several investigations. Here, we address the therapeutic effect of resveratrol on I/R-induced liver injury by focusing on unfolded protein response (UPR) signaling pathway.

Methods

Five minutes before reperfusion, resveratrol was injected into the tail vein of mice. They were ischemic for 1 h and then re-perfused for 3 h before being slaughtered (I/R). The activity of liver enzymes and the expression levels of genes involved in the unfolded protein response pathway were used to measure the hepatic damage.

Results

Our results revealed that the low dose of resveratrol (0.02 and 0.2 mg/kg) post-ischemic treatment significantly reduced the ALT and AST levels. In addition, compared with the control group, the expression of UPR pathway genes GRP78, PERK, IRE1α, CHOP, and XBP1 was significantly reduced in the resveratrol group. In the mice that received lower doses of resveratrol (0.02 and 0.2 mg/kg), the histopathological changes induced by I/R were significantly improved; however, the highest dose (2 mg/kg) of resveratrol could not significantly protect and solve the I/R damage.

Conclusion

The findings of this study suggest that hepatic ischemia occurs after liver transplantation and that receiving low-dose resveratrol treatment before reperfusion may promote graft survival through inhibition of UPR arms, especially PERK and IRE1α.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00611-4.

Metformin improves high‑fat diet‑induced insulin resistance in mice by downregulating the expression of long noncoding RNA NONMMUT031874.2

Metformin (MET) is the first-line therapeutic option for patients with type 2 diabetes that has garnered substantial attention over recent years. However, an insufficient number of studies have been performed to assess its effects on insulin resistance and the expression profile of long noncoding RNAs (lncRNAs). The present study divided mice into three groups: Control group, high-fat diet (HFD) group and HFD + MET group. A high-throughput sequencing analysis was conducted to detect lncRNA and mRNA expression levels, and differentially expressed lncRNAs were selected. Subsequently, the differentially expressed lncRNAs were validated both in vivo and in vitro (mouse liver AML12 cells treated with Palmitic acid) models of insulin resistance. After validating randomly selected lncRNAs via reverse transcription-quantitative PCR a novel lncRNA, NONMMUT031874.2, was identified, which was upregulated in the HFD group and reversed with MET treatment. To investigate the downstream mechanism of NONMMUT031874.2, lncRNA-microRNA (miR/miRNA)-mRNA co-expression network was constructed and NONCODE, miRBase and TargetScan databases were used, which indicated that NONMMUT031874.2 may regulate suppressor of cytokine signaling 3 by miR-7054-5p. For the in vitro part of the present study, AML12 cells were transfected with small interfering RNA to knock down NONMMUT031874.2 expression before being treated with palmitic acid (PA) and MET. The results showed that the expression of NONMMUT031874.2 was significantly increased whereas miR-7054-5p expression was significantly decreased by PA treatment. By contrast, after knocking down NONMMUT031874.2 expression or treatment with MET, the aforementioned in vitro observations were reversed. In addition, it was also found that NONMMUT031874.2 knockdown and treatment with MET exerted similar effects in alleviating insulin resistance and whilst decreasing glucose concentration in AML12 cells. These results suggest that MET treatment can ameliorate insulin resistance by downregulating NONMMUT031874.2 expression.

The Potential Application of Chinese Medicine in Liver Diseases: A New Opportunity

Liver diseases have been a common challenge for people all over the world, which threatens the quality of life and safety of hundreds of millions of patients. China is a major country with liver diseases. Metabolic associated fatty liver disease, hepatitis B virus and alcoholic liver disease are the three most common liver diseases in our country, and the number of patients with liver cancer is increasing. Therefore, finding effective drugs to treat liver disease has become an urgent task. Chinese medicine (CM) has the advantages of low cost, high safety, and various biological activities, which is an important factor for the prevention and treatment of liver diseases. This review systematically summarizes the potential of CM in the treatment of liver diseases, showing that CM can alleviate liver diseases by regulating lipid metabolism, bile acid metabolism, immune function, and gut microbiota, as well as exerting anti-liver injury, anti-oxidation, and anti-hepatitis virus effects. Among them, Keap1/Nrf2, TGF-β/SMADS, p38 MAPK, NF-κB/IκBα, NF-κB-NLRP3, PI3K/Akt, TLR4-MyD88-NF-κB and IL-6/STAT3 signaling pathways are mainly involved. In conclusion, CM is very likely to be a potential candidate for liver disease treatment based on modern phytochemistry, pharmacology, and genomeproteomics, which needs more clinical trials to further clarify its importance in the treatment of liver diseases.

Role of stilbenes against insulin resistance: A review

Insulin resistance (IR) is a state characterized by the inability of tissues to utilize blood glucose particularly liver, muscle, and adipose tissues resulting in hyperglycemia and hyperinsulinemia. A close relationship exists between IR and the development of type 2 diabetes (T2D). Therefore, therapeutic approaches to treat IR also improve T2D simultaneously. Scientific evidence has highlighted the major role of inflammatory cytokines, reactive oxygen species (ROS), environmental & genetic factors, and auto-immune disorders in the pathophysiology of IR. Among therapeutic remedies, nutraceuticals like polyphenols are being used widely to ameliorate IR due to their safer nature compared to pharmaceutics. Stilbenes are considered important metabolically active polyphenols currently under the limelight of research to cope with IR. In this review, efforts are made to elucidate cellular and subcellular mechanisms influenced by stilbenes including modulating insulin signaling cascade, correcting glucose transport pathways, lowering postprandial glucose levels, and protecting β-cell damage and its effects on the hyperactive immune system and proinflammatory cytokines to attenuate IR. Furthermore, future directions to further the research in stilbenes as a strong candidate against IR are included so that concrete recommendation for their use in humans is made.

Comparative analysis of long non‑coding RNA expression profiles induced by resveratrol and metformin treatment for hepatic insulin resistance

Resveratrol (RSV) and metformin (MET) play a role in the treatment of diabetes; however, the mechanisms through which they mediate insulin resistance by regulating long non‑coding RNAs (lncRNAs) remain unknown. The present study was conducted to determine whether RSV and MET can improve insulin resistance in the livers of high‑fat diet (HFD)‑fed mice by regulating lncRNAs. C57BL/6J mice were fed a HFD for 8 weeks to establish a model of insulin resistance. The mice were subsequently treated with RSV or MET for 8 weeks and liver tissue samples were then collected. High‑throughput sequencing was utilized to analyze mouse liver tissue samples to obtain differential lncRNA expression profiles. RSV or MET both reduced the blood glucose levels, the insulin index and the area under the curve in HFD‑fed mice. Treatment also improved liver structure and decreased lipid deposition in liver tissues, as shown by H&E and Oil Red O staining. Compared with the MET group, there were 55 lncRNAs and 19 mRNAs with a differential expression. In total, eight lncRNAs were randomly selected and evaluated by reverse transcription‑quantitative PCR (RT‑qPCR). The results of seven lncRNAs corresponded to those of the sequencing analysis. Pathway analysis revealed that the PI3K/Akt signaling pathway had the highest enrichment score. In addition, the results of western blot analysis and RT‑qPCR revealed that the expression levels of forkhead box O1, glucose‑6‑phosphatase catalytic subunit 1 and phosphoenolpyruvate carboxykinase 1 in the RSV and MET groups were significantly decreased compared with those in the HFD group. NONMMUT034936.2 and G6PC target genes exhibited similar expression patterns, indicating that RSV and MET may affect the PI3K/Akt signaling pathway through NONMMUT034936.2 to attenuate insulin resistance. On the whole, the present study provides novel biomarkers or contemporary perspectives for the use of RSV and MET in the treatment of insulin resistance and diabetes.

Zinc, selenium and chromium co-supplementation improves insulin resistance by preventing hepatic endoplasmic reticulum stress in diet-induced gestational diabetes rats

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications and results in adverse outcomes for pregnant women and their offspring. Endoplasmic reticulum (ER) stress is associated with insulin resistance and implicates in the development of GDM. Zinc, selenium and chromium have been shown to maintain glucose homeostasis via multiple mechanisms, but how these trace elements affect the insulin resistance and ER stress in GDM are largely unknown. To address this, a GDM rat model was induced by feeding female Sprague-Dawley rats a high-fat (45%) and sucrose diet, while zinc (10 mg/kg.bw), selenium (20 ug/kg.bw), chromium (20 ug/kg.bw) were daily supplemented alone or in combination from 6 weeks before mating to the end of lactation period. Maternal metabolic parameters, hepatic ER stress and insulin signaling were analyzed. The results showed that zinc, selenium and chromium co-supplementation dramatically alleviated high-fat and sucrose-induced glucose intolerance and oxidative stress during entire experiment period. Hepatic ER stress as well as the unfolded protein response was activated in GDM dams, characterized by the up-regulation of glucose-regulated protein 78, phosphorylated the protein kinase RNA-like endoplasmic reticulum kinase, and the inositol-requiring enzyme 1α. Zinc, selenium and chromium supplementation significantly prevented this activation, by which contributes to the promotion of the phosphorylated protein kinase B related insulin signaling and maintenance of glucose homeostasis. In conclusion, zinc, selenium and chromium supplementation may be a promising way to prevent the development of GDM by alleviating hepatic ER stress.

Resveratrol and Markers of Polycystic Ovary Syndrome: a Systematic Review of Animal and Clinical Studies

Polycystic ovary syndrome (PCOS) is a common disorder affecting childbearing-age women, and is associated with reproductive and metabolic disturbances. The present study aimed to systematically review current animal studies and randomized placebo-controlled clinical trials (RCT) regarding the effects of resveratrol, a natural polyphenolic compound, on PCOS features. PubMed, Scopus, Web of Knowledge, and Google Scholar were comprehensively searched until December 2020. All original animal articles and RCTs evaluating the effects of resveratrol on PCOS were eligible for the review. Out of 289 initial records, eight animal studies and three RCTs met our inclusion criteria. Most of the included animal studies reported beneficial effects of resveratrol on the histomorphological features, sex hormones and gonadotropins, glycemic control, inflammation, and oxidative stress. Resveratrol also ameliorated ovarian volume, high-quality oocyte rate, high-quality embryo rate, androgens and gonadotropins concentrations, angiogenic factors levels, and endoplasmic reticulum stress in PCOS patients. Upregulation of sirtuin-1 was an examined mechanism proposed for some observed effects of resveratrol. The current literature is limited to conclude the beneficial effects of resveratrol on the management of PCOS. Although, according to the promising results of the animal studies and limited RCTs, resveratrol might be an effective phytochemical in PCOS control, especially regarding hormonal and reproductive abnormalities. More mechanistic studies and RCTs are warranted to obvious whether resveratrol can be prescribed in the clinical situation.

Metabolic Syndrome and Psoriasis: Mechanisms and Future Directions

Psoriasis is an immune-mediated systemic disease with associated comorbidities, including metabolic syndrome (MetS) which contributes substantially to premature mortality in patients with psoriasis. However, the pathological mechanisms underlying this comorbidity are unclear. Studies have shown that the pathological parameters of psoriasis mediate the development of MetS. We reviewed the potential mechanisms which mediate the association between psoriasis and MetS, including endoplasmic reticulum stress, pro-inflammatory cytokine releases, excess production of reactive oxygen species, alterations in adipocytokine levels and gut microbiota dysbiosis. Here, we highlight important research questions regarding this association and offer insights into MetS research and treatment.

Resveratrol and endoplasmic reticulum stress: A review of the potential protective mechanisms of the polyphenol

The endoplasmic reticulum (ER) is an organelle that performs a set of essential functions in cellular biology. These include synthesis of lipids, homeostasis of calcium, and controlling the folding of proteins. Inflammation and oxidative stress are two important reasons behind the accumulation of misfolded or unfolded proteins in the ER. In such circumstances, a series of measures are undertaken in the cell which are collectively called unfolded protein response (UPR). The aim of UPR is to reduce the burden of protein aggregates and promote survival. However, extended and unrestricted ER stress (ERS) can induce further inflammation and apoptosis. ERS and the UPR are involved in different diseases such as neurodegenerative and cardiovascular diseases. Resveratrol (RSV), a natural polyphenol, has well-documented evidence supporting its numerous biological properties including antioxidant, antiinflammatory, antiobesity, antidiabetic, and antiischemic activities. The compound is also known for its potential beneficial effects on cognitive function and liver, kidney, and lung health. In this review, the role of ERS in several pathological conditions and the potential protective effects of RSV are discussed. However, the scarcity of clinical data means that more research needs to be conducted to gain a lucid understanding of RSV's effects on endoplasmic reticulum stress (ERS) in humans.

Resveratrol Alleviates the Inhibitory Effect of Tunicamycin-Induced Endoplasmic Reticulum Stress on Expression of Genes Involved in Thyroid Hormone Synthesis in FRTL-5 Thyrocytes

Recently, ER stress induced by tunicamycin (TM) was reported to inhibit the expression of key genes involved in thyroid hormone synthesis, such as sodium/iodide symporter (NIS), thyroid peroxidase (TPO) and thyroglobulin (TG), and their regulators such as thyrotropin receptor (TSHR), thyroid transcription factor-1 (TTF-1), thyroid transcription factor-2 (TTF-2) and paired box gene 8 (PAX-8), in FRTL-5 thyrocytes. The present study tested the hypothesis that resveratrol (RSV) alleviates this effect of TM in FRTL-5 cells. While treatment of FRTL-5 cells with TM alone (0.1 µg/mL) for 48 h strongly induced the ER stress-sensitive genes heat shock protein family A member 5 (HSPA5) and DNA damage inducible transcript 3 (DDIT3) and repressed NIS, TPO, TG, TSHR, TTF-1, TTF-2 and PAX-8, combined treatment with TM (0.1 µg/mL) and RSV (10 µM) for 48 h attenuated this effect of TM. In conclusion, RSV alleviates TM-induced ER stress and attenuates the strong impairment of expression of genes involved in thyroid hormone synthesis and their regulators in FRTL-5 thyrocytes exposed to TM-induced ER stress. Thus, RSV may be useful for the treatment of specific thyroid disorders, provided that strategies with improved oral bioavailability of RSV are applied.

Sex Hormone Binding Globulin (SHBG) Mitigates ER Stress in Hepatocytes In Vitro and Ex Vivo

Despite multiple research studies regarding metabolic syndrome and diabetes, the full picture of their molecular background and pathogenies remains elusive. The latest studies revealed that sex hormone-binding globulin (SHBG)-a serum protein released mainly by the liver-may participate in metabolic dysregulation, as its low serum level correlates with a risk for obesity, metabolic syndrome, and diabetes. Yet, the molecular phenomenon linking SHBG with these disorders remains unclear. In the presented study, we investigate how exogenous SHBG affects metabolically impaired hepatocytes with special attention to endoplasmic reticulum stress (ER stress) and lipid metabolism both in vitro and ex vivo. For that reason, palmitate-treated HepG2 cells and liver tissue samples collected post mortem were cultured in the presence of 50 nM and 100 nM SHBG. We found that SHBG protects against ER stress development and its progression. We have found that SHBG decreased the expression levels of inositol-requiring enzyme 1 (IRE1α), activating transcription factor 6 (ATF6), DNA damage-inducible transcript 3 (CHOP), and immunoglobulin heavy chain-binding protein (BIP). Furthermore, we have shown that it regulates lipolytic gene expression ex vivo. Additionally, herein, we deliver a novel large-animal model to study SHBG in translational research. Our data provide new insights into the cellular and molecular mechanisms by which SHBG modulates hepatocyte metabolism and offer a new experimental approach to study SHBG in human diseases.

Resveratrol Modulates the Gut-Brain Axis: Focus on Glucagon-Like Peptide-1, 5-HT, and Gut Microbiota

Resveratrol is a natural polyphenol that has anti-aging and anti-inflammatory properties against stress condition. It is reported that resveratrol has beneficial functions in various metabolic and central nervous system (CNS) diseases, such as obesity, diabetes, depression, and dementia. Recently, many researchers have emphasized the connection between the brain and gut, called the gut-brain axis, for treating both CNS neuropathologies and gastrointestinal diseases. Based on previous findings, resveratrol is involved in glucagon-like peptide 1 (GLP-1) secreted by intestine L cells, the patterns of microbiome in the intestine, the 5-hydroxytryptamine (5-HT) level, and CNS inflammation. Here, we review recent evidences concerning the relevance and regulatory function of resveratrol in the gut-brain axis from various perspectives. Here, we highlight the necessity for further study on resveratrol's specific mechanism in the gut-brain axis. We present the potential of resveratrol as a natural therapeutic substance for treating both neuropathology and gastrointestinal dysfunction.

Resveratrol Metabolites Are Able to Reduce Steatosis in Cultured Hepatocytes

Steatosis is characterized primarily by excessive lipid accumulation in the form of triglycerides in the liver. Although resveratrol shows a low bioavailability, it has significant positive effects on steatosis. The aim of this study was to analyze whether some phase II and microbial resveratrol metabolites (trans-resveratrol-4'-O-glucuronide (R-4G); trans-resveratrol-3-O-glucuronide (R-3G); trans-resveratrol-3-O-sulfate (R-S) and dihydro-resveratrol (DH-R) were effective in reducing hepatocyte fat accumulation. An in vitro model mimicking the hepatocyte situation in fatty liver was developed by incubating mouse AML12 hepatocytes with palmitic acid (PA). For cell treatments, hepatocytes were incubated with 1, 10, or 25 µM resveratrol or its metabolites. Triglycerides and cell viability were assessed using commercial kits. Protein expression of enzymes and transporters involved in triglyceride metabolism were analyzed by western blot. We show for the first time that resveratrol and all the tested metabolites, at 1 µM, partially prevented lipid accumulation induced by the saturated fatty acid PA in AML12 hepatocytes. This effect was mainly due to the inhibition of de novo lipogenesis. This demonstrates that the low bioavailability of resveratrol is not as big a problem as it was thought to be, because resveratrol metabolites contribute to the delipidating effects of the parent compound.

Influence of Resveratrol on the Cardiovascular Health Effects of Chronic Kidney Disease

Cardiovascular disease (CVD) is closely related to chronic kidney disease (CKD), and patients with CKD have a high risk of CVD-related mortality. Traditional CVD risk factors cannot account for the higher cardiovascular risk of patients with CKD, and standard CVD interventions cannot reduce the mortality rates among patients with CKD. Nontraditional factors related to mineral and vitamin-D metabolic disorders provide some explanation for the increased CVD risk. Non-dialyzable toxins, indoxyl sulfate (IS) and p-cresol sulfate (PCS)—produced in the liver by colonic microorganisms—cause kidney and vascular dysfunction. Plasma trimethylamine-N-oxide (TMAO)—a gut microbe-dependent metabolite of dietary L-carnitine and choline—is elevated in CKD and related to vascular disease, resulting in poorer long-term survival. Therefore, the modulation of colonic flora can improve prospects for patients with CKD. Managing metabolic syndrome, anemia, and abnormal mineral metabolism is recommended for the prevention of CVD in patients with CKD. Considering nontraditional risk factors, the use of resveratrol (RSV), a nutraceutical, can be helpful for patients with CVD and CKD. This paper discusses the beneficial effects of RSV on biologic, pathophysiological and clinical responses, including improvements in intestinal epithelial integrity, modulation of the intestinal microbiota and reduction in hepatic synthesis of IS, PCS and TMAO in patients with CVD and CKD.

Long non-coding RNA expression profiling following treatment with resveratrol to improve insulin resistance

Resveratrol (RSV) and long non-coding RNAs (lncRNAs) play a role in the treatment of diabetes; however, the mechanism by which resveratrol regulates insulin resistance via lncRNAs is currently unknown. The present study aimed to determine the lncRNA expression level profile in mice following resveratrol treatment to improve insulin resistance using high-throughput sequencing technology. C57BL/6J mice were fed a high-fat diet for 8 weeks to develop an insulin resistance model, followed by treatment with or without RSV for 6 weeks before high-throughput sequencing. Following RSV treatment, 28 and 30 lncRNAs were up- and downregulated, respectively; eight lncRNAs were randomly selected and evaluated using reverse transcription-quantitative PCR, which showed results consistent with the sequencing analysis. Pathway analysis demonstrated that the insulin signaling pathway enrichment score was the highest, and identified two lncRNAs, NONMMUT058999.2 and NONMMUT051901.2, consistent with the protein-encoding genes SOCS3 and G6PC, respectively. Similar expression level patterns were observed for SOCS3 and G6PC, suggesting that RSV improves insulin resistance by modulating lncRNAs. RSV decreased the expression levels of SOCS3, FOXO1, G6PC and PEPCK in mice. The same results were observed following knockdown of NONMMUT058999.2 in cells. The present study provides a new biomarker or intervention target for RSV in the treatment of diabetes, and a new perspective for understanding the hypoglycemic mechanism of RSV.

Exogenous spermine attenuates myocardial fibrosis in diabetic cardiomyopathy by inhibiting endoplasmic reticulum stress and the canonical Wnt signaling pathway

Myocardial fibrosis is one of the main pathological manifestations of diabetic cardiomyopathy (DCM). Spermine (SPM), a product of polyamine metabolism, plays an important role in many cardiac diseases including hypertrophy, ischemia, and infarction, but its role in diabetic myocardial fibrosis has not been clarified. This study aimed to investigate the role of polyamine metabolism, specifically SPM, in diabetic myocardial fibrosis and to explore the related mechanisms. We used intraperitoneal injection of streptozotocin (STZ, 60 mg/kg) in Wistar rats and high glucose (HG, 40 mM) stimulated cardiac fibroblasts (CFs) to established a type 1 diabetes (T1D) model in vivo and in vitro, which were pretreated with exogenous SPM (5 mg/kg per day and 5 μM). The results showed that hyperglycemia induced the expression of the key polyamine synthesis enzyme ornithine decarboxylase (ODC) decreased and the key catabolic enzyme spermidine/spermine N¹ -acetyltransferase (SSAT) increased compared with those in the control group. The body weight, blood insulin level, and cardiac ejection function were decreased, while blood glucose, heart weight, the ratio of heart weight to body weight, myocardial interstitial collagen deposition, and endoplasmic reticulum stress (ERS)-related protein (glucose-regulated protein-78, glucose-regulated protein-94, activating transcription factor-4, and C/EBP homology protein) expression in the T1D group were all significantly increased. HG also caused an increased expression of Wnt3, β-catenin (in cytoplasm and nucleus), while Axin2 and phosphorylated β-catenin decreased. Exogenous SPM improved the above changes caused by polyamine metabolic disorders. In conclusion, polyamine metabolism disorder occurs in the myocardial tissue of diabetic rats, causing myocardial fibrosis and ERS. Exogenous SPM plays a myocardial protective role via inhibiting of ERS and the canonical Wnt/β-catenin signaling pathway.

Endoplasmic reticulum stress and destruction of pancreatic β cells in type 1 diabetes

Type 1 diabetes (T1D) results from dysfunction of pancreatic islets β cells. Recent studies supported that endoplasmic reticulum (ER) stress takes an important role in pancreatic β cell excessive loss, resulting in T1D. Here, we aimed to review the relationship between ER stress and T1D. Additionally, we also reviewed the potential mechanisms underlying ER stress mediated T1D. Studies have shown that severe ER stress is directly involved in the pancreatic β cells destruction and pathogenesis of T1D. ER stress plays a key part in pancreatic β cells and T1D, which will help in developing new effective therapeutics for T1D.