Resveratrol Influences Pancreatic Islets by Opposing Effects on Electrical Activity and Insulin Release

Systematic review and meta-analysis of the interventional effects of resveratrol in a rat model of myocardial ischemia-reperfusion injury

Objective: To evaluate the intervention effect of resveratrol on rat model of myocardial ischemia-reperfusion injury. Methods: The relevant studies on the intervention of resveratrol on rat models of myocardial ischemia reperfusion injury were searched in PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang and China Science and Technology Journal Database from the start of database establishment to January 2023. Data were extracted from studies that met the inclusion criteria. The results included electrocardiogram (ECG) and myocardial injury markers: ST changes, cardiac troponin I (cTn-I), cardiac troponin T (cTn-T), creatine kinase (CK), creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH); hemodynamic indicators: heart rate (HR), left ventricular diastolic pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), left ventricular systolic pressure (LVSP), maximum rate of increase of left ventricular pressure (+dp/dtmax), maximum rate of decrease of left ventricular pressure (-dp/dtmax); oxidative damage indicators: nitric oxide (NO), reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA); inflammatory factors: tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6); apoptosis index: B-cell lymphoma-2 (Bcl-2), BCL2-Associated X (Bax), cardiomyocyte apoptosis index (AI); heart tissue structure: myocardial infarction size. Finally, a meta-analysis of these results was conducted. The methodological quality of the studies was assessed using the SYRCLE Bias Risk tool. Results: A total of 43 studies were included in the meta-analysis, and the quality of the included studies was assessed. It was found that the evidence quality of these 43 studies was low, and no study was judged to have low risk bias in all risk assessments. The results showed that resveratrol could reduce ST segment, cTn-I, cTn-T, CK, CK-MB, LDH, LVEDP, ROS, MDA, TNF-α, IL-6, AI levels and myocardial infarction size. HR, LVDP, LVSP, +dp/dtmax, NO, Bcl-2, and SOD levels were increased. However, resveratrol had no significant effect on -dp/dtmax and Bax outcome measures. Conclusion: Resveratrol can reduce ST segment in rat model of myocardial ischemia-reperfusion injury, alleviate myocardial injury, improve ventricular systolic and diastolic ability in hemodynamics, reduce inflammatory response and oxidative damage, and reduce myocardial necrosis and apoptosis. Due to the low quality of the methodologies included in the studies, additional research is required.

The protective role of resveratrol in diabetic wound healing

Diabetic wounds are severe complications of diabetes mellitus (DM), which have difficulty in healing. Although diverse treatments have been used, the prognosis of diabetic wounds is not satisfactory; therefore, an effective therapy to accelerate diabetic wound healing is urgently needed. In our review, we summarized that resveratrol can promote diabetic wound healing by protecting against hyperglycemia, inflammation, oxidative stress, vascular pathology, infection, and peripheral neuropathy. To clarify it clearly, we highlighted its underlying mechanisms of protective effects of resveratrol against diabetic wounds, and high-quality studies are needed to firmly establish its clinical efficacy. Otherwise, with the development of material sciences, resveratrol can exert its therapeutic effectiveness efficiently; however, more high-quality studies are needed to confirm the clinical efficacy of resveratrol on diabetic wounds.

Dietary Bioactive Ingredients Modulating the cAMP Signaling in Diabetes Treatment

As the prevalence of diabetes increases progressively, research to develop new therapeutic approaches and the search for more bioactive compounds are attracting more attention. Over the past decades, studies have suggested that cyclic adenosine monophosphate (cAMP), the important intracellular second messenger, is a key regulator of metabolism and glucose homeostasis in diverse physiopathological states in multiple organs including the pancreas, liver, gut, skeletal muscle, adipose tissues, brain, and kidney. The multiple characteristics of dietary compounds and their favorable influence on diabetes pathogenesis, as well as their intersections with the cAMP signaling pathway, indicate that these compounds have a beneficial effect on the regulation of glucose homeostasis. In this review, we outline the current understanding of the diverse functions of cAMP in different organs involved in glucose homeostasis and show that a diversity of bioactive ingredients from foods activate or inhibit cAMP signaling, resulting in the improvement of the diabetic pathophysiological process. It aims to highlight the diabetes-preventative or -therapeutic potential of dietary bioactive ingredients targeting cAMP signaling.

Microelectrode Array based Functional Testing of Pancreatic Islet Cells

Electrophysiological techniques to characterize the functionality of islets of Langerhans have been limited to short-term, one-time recordings such as a patch clamp recording. We describe the use of microelectrode arrays (MEAs) to better understand the electrophysiology of dissociated islet cells in response to glucose in a real-time, non-invasive method over prolonged culture periods. Human islets were dissociated into singular cells and seeded onto MEA, which were cultured for up to 7 days. Immunofluorescent imaging revealed that several cellular subtypes of islets; β, δ, and γ cells were present after dissociation. At days 1, 3, 5, and 7 of culture, MEA recordings captured higher electrical activities of islet cells under 16.7 mM glucose (high glucose) than 1.1 mM glucose (low glucose) conditions. The fraction of the plateau phase (FOPP), which is the fraction of time with spiking activity recorded using the MEA, consistently showed distinguishably greater percentages of spiking activity with high glucose compared to the low glucose for all culture days. In parallel, glucose stimulated insulin secretion was measured revealing a diminished insulin response after day 3 of culture. Additionally, MEA spiking profiles were similar to the time course of insulin response when glucose concentration is switched from 1.1 to 16.7 mM. Our analyses suggest that extracellular recordings of dissociated islet cells using MEA is an effective approach to rapidly assess islet functionality, and could supplement standard assays such as glucose stimulate insulin response.

Resveratrol protects against ethanol-induced impairment of insulin secretion in INS-1 cells through SIRT1-UCP2 axis

SIRT1 has been proposed to enhance insulin secretion in β-cell through repressing the expression of uncoupling protein2 (UCP2), but whether ethanol-induced β-cell dysfunction is mediated by the disrupted SIRT1-UCP2 axis remains unknown. This study was conducted to explore the underlying mechanisms by which ethanol resulted in β-cell dysfunction and the potential protective effects of resveratrol in this process. INS-1 cells (rat pancreatic β-cell line) were cultured with ethanol in the presence or absence of resveratrol (2.5, 12.5 μmol/L). The results showed that ethanol exposure reduced glucose-stimulated insulin secretion, ATP production and SIRT1 expression but increased UCP2 expression, while supplementation with resveratrol restored the function of INS-1 cell by upregulating SIRT1 and inhibiting UCP2. Moreover, the critical role of SIRT1-UCP2 axis was further supported by the results that SIRT1 activator SRT1720 reversed ethanol-induced impairment of glucose-stimulated insulin secretion by decreasing UCP2, while SIRT1 inhibitor Ex527 abolished the beneficial effects of resveratrol. Meanwhile, NAD⁺ booster nicotinamide mononucleotide also counteracted the deleterious effects of ethanol by increasing SIRT1, suggesting the regulation of SIRT1-UCP2 axis may be associated with cellular NAD⁺/NADH ratio. In conclusion, our observations imply that ethanol induces impaired insulin secretion from INS-1 cell through disrupting SIRT1-UCP2 axis, while resveratrol may reverse this process by augmenting SIRT1 and inhibiting UCP2.

Resveratrol promotes trophoblast invasion in pre-eclampsia by inducing epithelial-mesenchymal transition

Impairment spiral arteries remodelling was considered to be the underlying cause of pathogenesis of pre‐eclampsia (PE). Resveratrol (RE) was reported that it could modulate cellar phenotype to ameliorate diverse human diseases. However, the biological function of RE in PE remains poorly understood. In this report, we investigated the effect of RE on trophoblast phenotype both in vivo and in vitro. We conducted MTT and transwell assays to explore cell proliferation and invasion events in HTR‐8/SVneo. In mice model, the clinical characteristics of PE were established through the injection of NG‐nitro‐l‐arginine methyl ester (L‐NAME). Furthermore, related experiments were performed to detect cellar phenotype‐associated signalling pathway, including epithelial‐mesenchymal transition (EMT) and Wnt/β‐catenin. Cell assays indicated that RE could increase trophoblasts migration and invasion. In addition, hypertension and proteinuria were markedly ameliorated by RE compared with the controls in PE mice model. Moreover, treatment by RE in trophoblasts or in PE model, we found that RE activated EMT progress through the regulation of E‐cadherin, β‐catenin, N‐cadherin, vimentin expression, and further altered the WNT‐related gene expression, including WNT1, WNT3 and WNT5B. Our findings demonstrated that RE might stimulate the invasive capability of human trophoblasts by promoting EMT and mediating the Wnt/β‐catenin pathway in PE.