Fisetin protects against streptozotocin-induced diabetic cardiomyopathy in rats by suppressing fatty acid oxidation and inhibiting protein kinase R

Fisetin mitigates letrozole-induced polycystic ovarian syndrome in rats: crosstalk of AMPK/PI3K/AKT-mediated-Nrf2 antioxidant defense mechanism and the inflammasome NLRP3/NF-κB P65/IL-1β signaling pathways

Polycystic ovarian syndrome (PCOS) is a highly prevalent condition affecting reproductive-aged women, causing insulin resistance, hyperandrogenism, weight gain, and menstrual problems. The present study intended to investigate the potential role of fisetin (FT) in letrozole (LZ)-induced PCOS in adult female rats and the possible mechanism underlying its action. PCOS was induced by oral administration of LZ (1 mg/kg) for 21 days. Treated rats received FT (1.25 or 2.5 mg/kg) orally once daily for 14 consecutive days. Following the experimental duration, blood samples and ovary tissues were isolated and preserved for biochemical and histopathological examinations. The results revealed that LZ-induced PCOS led to significant abnormalities in sex hormones and metabolic parameters. Additionally, it initiated an inflammatory cascade, evidenced by activation of the NF-κB p65/IL-1β and AMPK/PI3K/AKT pathways, alongside downregulation of Nrf2 ovarian gene expression and NLRP3 inflammasome activity, which enhanced the production of proinflammatory cytokines. FT demonstrated its beneficial impacts by restoring hormonal disturbance and reversing the imbalanced metabolic parameters. Moreover, FT increased the mRNA of ovarian Nrf2 levels and suppressed the up-regulated inflammatory IL-1β/NF-κB p65 signaling pathway, consequently alleviating the elevated levels of ovarian NLRP3. The histopathological examination also confirmed that FT has a beneficial effect in ameliorating PCOS, consistent with the aforementioned parameters. Finally, the present results demonstrated that FT ameliorates LZ-induced PCOS through the intricate interplay between the AMPK/PI3K/AKT-mediated Nrf2 antioxidant defense mechanism and the regulation of the inflammasome NLRP3/NF-κB p65/IL-1β signaling pathways.

Association of high-sensitivity troponin T with left ventricular dysfunction in prediabetes

BACKGROUND

Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) are an increasingly serious problem worldwide. Tissue Doppler imaging (TDI), a non-invasive technique, may evaluate both systolic and diastolic function during the first phases of cardiovascular disease (CVD). High-sensitivity cardiac troponin T (hs-cTnT) can detect subclinical myocardial injury in asymptomatic prediabetic patients.

AIM

We aimed to investigate the relationship between left ventricular (LV) function and hs-cTnT in prediabetic patients.

METHODS

Between 1 October 2021 and 1 October 2022, we recruited 96 prediabetic and an equal number of age- and gender-matched healthy volunteers prospectively. TDI was used to evaluate both systolic and diastolic functions. Hs-cTnT levels were obtained and compared between groups.

RESULTS

It was found that the values for mitral annular plane systolic excursion (MAPSE), E, the rapid filling wave, E/Em, and the peak annular velocities of systolic excursion in the ejection period (Sm) were all significantly higher in these patients compared to healthy individuals (p < .001). Hs-cTnT was an independent predictor of left ventricular diastolic dysfunction (LVDD) and left ventricular systolic dysfunction (LVSD) (odds ratio [OR] = 2.625, 95% confidence interval [CI] = 1.324-4.308, p < .001, and OR = 1.922, 95% CI = 0.454-3.206, p = .004).

CONCLUSIONS

Prediabetics had higher hs-cTnT levels than controls. We showed that LVSD and LVDD functions were negatively affected in prediabetic patients. Our results proved that hs-cTnT levels may be associated with subclinical LV dysfunction in prediabetes.

Ferroptosis: Latest evidence and perspectives on plant-derived natural active compounds mitigating doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is a chemotherapy drug widely used in clinical settings, acting as a first-line treatment for various malignant tumors. However, its use is greatly limited by the cardiotoxicity it induces, including doxorubicin-induced cardiomyopathy (DIC). The mechanisms behind DIC are not fully understood, but its potential biological mechanisms are thought to include oxidative stress, inflammation, energy metabolism disorders, mitochondrial damage, autophagy, apoptosis, and ferroptosis. Recent studies have shown that cardiac injury induced by DOX is closely related to ferroptosis. Due to their high efficacy, availability, and low side effects, natural medicine treatments hold strong clinical potential. Currently, natural medicines have been shown to mitigate DOX-induced ferroptosis and ease DIC through various functions such as antioxidation, iron ion homeostasis correction, lipid metabolism regulation, and mitochondrial function improvement. Therefore, this review summarizes the mechanisms of ferroptosis in DIC and the regulation by natural plant products, with the expectation of providing a reference for future research and development of inhibitors targeting ferroptosis in DIC. This review explores the mechanisms of ferroptosis in doxorubicin-induced cardiomyopathy (DIC) and summarizes how natural plant products can alleviate DIC by inhibiting ferroptosis through reducing oxidative stress, correcting iron ion homeostasis, regulating lipid metabolism, and improving mitochondrial function.

A Review on the Natural Products in Treatment of Diabetic Cardiomyopathy (DCM)

Diabetic cardiomyopathy is an insidious and fatal disease, imposing major financial and social burdens on affected individuals. Among the various methods proposed for the treatment of diabetic cardiomyopathy (DCM), treatments with natural products have achieved promising results due to their high efficiency and minimal side-effects. Literature was searched, analyzed, and collected using databases, including PubMed, Web of Science, Excerpt Medica, Science Direct, and Springer. In this study, we reviewed the DCM-related studies on 72 representative natural products. These natural products have been confirmed to be applicable in the therapeutic intervention of DCM, acting through various mechanisms such as the amelioration of metabolic abnormalities, protecting the mitochondrial structure and function, anti-oxidant stress, anti-inflammatory, anti-fibrosis, regulation of Ca 2 + homeostasis and regulation of programmed cell death. The nuclear factor kappa B (NF- κ B), nuclear factor erythroid 2-related factor 2 (Nrf-2), and transforming growth factor- β (TGF- β ) have been extensively studied as high frequency signaling pathways for natural product intervention in DCM. The effectiveness of natural products in treating DCM has been revealed and studied, which provides a reference for DCM-specific drug discovery.

Esculeoside A Decreases Diabetic Cardiomyopathy in Streptozotocin-Treated Rats by Attenuating Oxidative Stress, Inflammation, Fibrosis, and Apoptosis: Impressive Role of Nrf2

Background and Objectives: This experiment evaluated the preventative influence of the tomato-derived Esculeoside A (ESA) on diabetic cardiomyopathy in type 1 diabetes mellitus (T1DM) in rats induced by streptozotocin (STZ). It also examined whether the activation of Nrf2 signaling affords this protection. Materials and Methods: Adult male Wistar control nondiabetic rats and rats with T1DM (STZ-T1DM) were given either carboxymethylcellulose as a vehicle or ESA (100 mg/kg) (eight rats/group) orally daily for 12 weeks. A group of STZ-T1DM rats was also treated with 100 mg/kg ESA and co-treated i.p. with 2 mg/kg (twice/week), brusatol, and Nrf2 inhibitors for 12 weeks. Results and Conclusions: Treatment with ESA prevented the gain in heart weight and cardiomyocyte hypertrophy and improved the left ventricular (LV) systolic and diastolic function (LV) in the STZ-T1DM rat group. Likewise, it reduced their serum levels of triglycerides, cholesterol, and low-density lipoproteins (LDL-c), as well as their LV mRNA, cytoplasmic total, and nuclear total levels of NF-κB. ESA also reduced the total levels of malondialdehyde, tumor necrosis factor-α, interleukine-6 (IL-6), Bax, cytochrome-c, and caspase-3 in the LV of the STZ-T1DM rats. In parallel, ESA enhanced the nuclear and cytoplasmic levels of Nrf2 and the levels of superoxide dismutase, glutathione, and heme oxygenase-1, but decreased the mRNA and cytoplasmic levels of keap-1 in the LVs of the STZ-T1DM rats. Interestingly, ESA did not affect the fasting insulin and glucose levels of the diabetic rats. All of these beneficially protective effects of ESA were not seen in the ESA-treated rats that received brusatol. In conclusion, ESA represses diabetic cardiomyopathy in STZ-diabetic hearts by activating the Nrf2/antioxidant/NF-κB axis.

Fisetin-In Search of Better Bioavailability-From Macro to Nano Modifications: A Review

As secondary plant metabolites, polyphenols are abundant in fruits and vegetables. They are in high demand because of their many health benefits. However, their low bioavailability makes them complex compounds to use for therapeutic purposes. Due to the limited solubility of phytocompounds, dietary supplements made from them may only be partially effective. Such molecules include fisetin, found in strawberries, and have shown great promise in treating Alzheimer's disease and cancer. Unfortunately, because of their limited water solubility, low absorption, and poor bioavailability, the assistance of nanotechnology is required to allow them to fulfil their potential fully. Here, we provide evidence that nanodelivery methods and structure modifications can improve fisetin bioavailability, which is linked to improvements in therapeutic efficacy. An open question remains as to which nanocarrier should be chosen to meet the abovementioned requirements and be able to enhance fisetin's therapeutic potential to treat a particular disease.

Nrf2 signaling in diabetic nephropathy, cardiomyopathy and neuropathy: Therapeutic targeting, challenges and future prospective

Western lifestyle contributes to an overt increase in the prevalence of metabolic anomalies including diabetes mellitus (DM) and obesity. Prevalence of DM is rapidly growing worldwide, affecting many individuals in both developing and developed countries. DM is correlated with the onset and development of complications with diabetic nephropathy (DN), diabetic cardiomyopathy (DC) and diabetic neuropathy being the most devastating pathological events. On the other hand, Nrf2 is a regulator for redox balance in cells and accounts for activation of antioxidant enzymes. Dysregulation of Nrf2 signaling has been shown in various human diseases such as DM. This review focuses on the role Nrf2 signaling in major diabetic complications and targeting Nrf2 for treatment of this disease. These three complications share similarities including the presence of oxidative stress, inflammation and fibrosis. Onset and development of fibrosis impairs organ function, while oxidative stress and inflammation can evoke damage to cells. Activation of Nrf2 signaling significantly dampens inflammation and oxidative damage, and is beneficial in retarding interstitial fibrosis in diabetic complications. SIRT1 and AMPK are among the predominant pathways to upregulate Nrf2 expression in the amelioration of DN, DC and diabetic neuropathy. Moreover, certain therapeutic agents such as resveratrol and curcumin, among others, have been employed in promoting Nrf2 expression to upregulate HO-1 and other antioxidant enzymes in the combat of oxidative stress in the face of DM.

Targeting ferroptosis as a promising therapeutic strategy to treat cardiomyopathy

Cardiomyopathies are a clinically heterogeneous group of cardiac diseases characterized by heart muscle damage, resulting in myocardium disorders, diminished cardiac function, heart failure, and even sudden cardiac death. The molecular mechanisms underlying the damage to cardiomyocytes remain unclear. Emerging studies have demonstrated that ferroptosis, an iron-dependent non-apoptotic regulated form of cell death characterized by iron dyshomeostasis and lipid peroxidation, contributes to the development of ischemic cardiomyopathy, diabetic cardiomyopathy, doxorubicin-induced cardiomyopathy, and septic cardiomyopathy. Numerous compounds have exerted potential therapeutic effects on cardiomyopathies by inhibiting ferroptosis. In this review, we summarize the core mechanism by which ferroptosis leads to the development of these cardiomyopathies. We emphasize the emerging types of therapeutic compounds that can inhibit ferroptosis and delineate their beneficial effects in treating cardiomyopathies. This review suggests that inhibiting ferroptosis pharmacologically may be a potential therapeutic strategy for cardiomyopathy treatment.

Flavonoids' Dual Benefits in Gastrointestinal Cancer and Diabetes: A Potential Treatment on the Horizon?

Diabetes and gastrointestinal cancers (GI) are global health conditions with a massive burden on patients' lives worldwide. The development of both conditions is influenced by several factors, such as diet, genetics, environment, and infection, which shows a potential link between them. Flavonoids are naturally occurring phenolic compounds present in fruits and vegetables. Once ingested, unabsorbed flavonoids reaching the colon undergo enzymatic modification by the gut microbiome to facilitate absorption and produce ring fission products. The metabolized flavonoids exert antidiabetic and anti-GI cancer properties, targeting major impaired pathways such as apoptosis and cellular proliferation in both conditions, suggesting the potentially dual effects of flavonoids on diabetes and GI cancers. This review summarizes the current knowledge on the impact of flavonoids on diabetes and GI cancers in four significant pathways. It also addresses the synergistic effects of selected flavonoids on both conditions. While this is an intriguing approach, more studies are required to better understand the mechanism of how flavonoids can influence the same impaired pathways with different outcomes depending on the disease.

Topical application of Aloe gel and/or olive oil combination promotes the wound healing properties of streptozotocin-induced diabetic rats

Diabetic wounds are characterized by a delayed closure rate due to the excess inflammation and the inhibition of angiogenesis. Natural products derived from Aloe vera have shown great promise due to their healing magnificent properties. Olive oil is another natural product with anti-microbial and anti-inflammatory properties that may contribute to the healing process. In the present investigation, we tried to evaluate the efficacy of topical application of Aloe gel and/or olive oil in the enhancement of diabetic wounds using histological and immunohistochemical analysis. Excisional wounds were created on the back skin of streptozotocin-induced diabetic rats. Topical treatments of Aloe gel and/or olive oil were applied separately and in a combination (AVO) daily for experimental groups. Macroscopic and microscopic observations of the excision wounds were monitored at time intervals (3, 6, 9, 14 days) post-wounding. Macroscopic observations of the AVO group exhibited almost complete healing at day 14, while other groups were still in progress. Similarly, immunohistochemical analysis of the AVO group showed a mild expression pattern of NF-κB.. While, the cell proliferation (Ki-67), and angiogenesis (CD34) markers were upregulated. Conclusively, the obtained results showed that the AVO combination effectively improved the healing process in diabetic excisional wounds with significant differences in the healing kinetics compared to wounds that received Aloe gel or olive oil separately.

Cardioprotective Effect of Gynostemma pentaphyllum against Streptozotocin Induced Cardiac Toxicity in Rats via Alteration of AMPK/Nrf2/HO-1 Pathway

Gynostemma pentaphyllum (GP) is a plant commonly used in diabetic therapy in China. GP having potent antioxidant effect against various free radicals. The purpose of the current investigation to identify the cardioprotective effect of GP against streptozotocin (STZ)/ high fat diet (HFD) induced cardiac dysfunction in rats via alteration of AMPK/Nrf2/HO-1 pathway. Wistar rats were used for the current protocol. The rats were received the intraperitoneal injection of STZ and HFD to induce the cardiac remodelling. Blood glucose level, insulin and lipid parameters were estimated. Blood pressure and heart rate were also estimated. Cardiac parameters, antioxidant, cytokines, total protein and inflammatory mediators were analysed. The mRNA expression was detected using the RT-qPCR, respectively. GP significantly (p < 0.001) decreased the BGL and improved the insulin level. GP altered the ratio of heart/BW, liver/BW, and lung/BW. GP treatment significantly (p < 0.001) suppressed the heart rate and blood pressure (diastolic, systolic and mean pressure). GP significantly (p < 0.001) reduced the level of TC, LDL, TG, VLDL and increased the level of HDL. DCM induced rats received the GP administration exhibited reduction in the level of CK and LDH. GP significantly (p < 0.001) reduced the levels of MDA, hydrogen peroxide, peroxynitrite, ROS and increased the level of GSH, SOD, CAT and GPx. GP significantly (p < 0.001) reduced the levels of cytokines (TNF-α, IL-6, IL-1β) and inflammatory parameters (COX-2 and NFκB). GP significantly (p < 0.001) suppressed the NLRP3 and NF-κB expression. GP also boosted mitochondrial biogenesis by boosting the PGC-1α, HO-1 and Nrf2 expression in cardiac tissue. GP treatment showed the cardioprotective effects against STZ induced diabetic cardiac dysfunction via alteration of AMPK/Nrf2/HO-1 pathway.

Cardioprotective effects of phytopigments via multiple signaling pathways

BACKGROUND

Cardiovascular diseases (CVDs) are among the deadliest non-communicable diseases, and millions of dollars are spent every year to combat CVDs. Unfortunately, the multifactorial etiology of CVDs complicates the development of efficient therapeutics. Interestingly, phytopigments show significant pleiotropic cardioprotective effects both in vitro and in vivo.

PURPOSE

This review gives an overview of the cardioprotective effects of phytopigments based on in vitro and in vivo studies as well as clinical trials.

METHODS

A literature-based survey was performed to collect the available data on cardioprotective activities of phytopigments via electronic search engines such as PubMed, Google Scholar, and Scopus.

RESULTS

Different classes of phytopigments such as carotenoids, xanthophylls, flavonoids, anthocyanins, anthraquinones alleviate major CVDs (e.g., cardiac hypertrophy, atherosclerosis, hypertension, cardiotoxicities) via acting on signaling pathways related to AMPK, NF-κB, NRF2, PPARs, AKT, TLRs, MAPK, JAK/STAT, NLRP3, TNF-α, and RA.

CONCLUSION

Phytopigments represent promising candidates to develop novel and effective CVD therapeutics. More randomized, placebo-controlled clinical studies are recommended to establish the clinical efficacy of phytopigments.

Quercetin Inhibits Pyroptosis in Diabetic Cardiomyopathy through the Nrf2 Pathway

The present study investigated whether quercetin promotes the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) to inhibit pyroptosis progression and ameliorate diabetic cardiomyopathy. We evaluated the protective effects of quercetin against diabetic cardiomyopathy by analyzing the expression of pyroptosis pathway proteins, myocardial cell apoptosis rate, degree of myocardial fibrosis, and serum inflammatory indices in the hearts of model rats with diabetes. We evaluated the expression of Nrf2 in the nucleus of cardiomyocytes and H9C2 cells to clarify the role of quercetin in promoting the nuclear translocation of Nrf2. In addition, we coincubated cardiomyocytes with the Nrf2 inhibitor ML385 to confirm that quercetin inhibits the diabetes-induced cardiomyocyte pyroptosis via the Nrf2 pathway. We found that quercetin promoted the nuclear translocation of Nrf2 in cardiac cells of diabetic rats, increased the expression of the antioxidant proteins HO-1, GCLC, and SOD, reduced the accumulation of ROS and the degree of cardiomyocyte apoptosis, and alleviated diabetes-induced cardiac fibrosis. The therapeutic effects of quercetin were further validated in H9C2 cardiomyocytes. Interestingly, ML385 prevented the beneficial effects of quercetin on diabetic cardiomyopathy, further indicating that the quercetin-mediated inhibition of pyroptosis requires the participation of the Nrf2 pathway. In conclusion, quercetin promoted the nuclear translocation of Nrf2, increased the expression of antioxidant factors in cells, and inhibited the progression of cell pyroptosis, thereby alleviating diabetic cardiomyopathy.

Omnifarious fruit polyphenols: an omnipotent strategy to prevent and intervene diabetes and related complication?

Diabetes mellitus is a metabolic syndrome which cannot be cured. Recently, considerable interest has been focused on food ingredients to prevent and intervene in complications of diabetes. Polyphenolic compounds are one of the bioactive phytochemical constituents with various biological activities, which have drawn increasing interest in human health. Fruits are part of the polyphenol sources in daily food consumption. Fruit-derived polyphenols possess the anti-diabetic activity that has already been proved either from in vitro studies or in vivo studies. The mechanisms of fruit polyphenols in treating diabetes and related complications are under discussion. This is a comprehensive review on polyphenols from the edible parts of fruits, including those from citrus, berries, apples, cherries, mangoes, mangosteens, pomegranates, and other fruits regarding their potential benefits in preventing and treating diabetes mellitus. The signal pathways of characteristic polyphenols derived from fruits in reducing high blood glucose and intervening hyperglycemia-induced diabetic complications were summarized.

Bee venom ameliorates cardiac dysfunction in diabetic hyperlipidemic rats

High levels of blood glucose and lipids are well-known risk factors for heart diseases. Bee venom is a natural product that has a potent hypoglycemic, hypolipidemic, anti-inflammatory, and antioxidant effects. The current study aimed to determine the bee venom effects on cardiac dysfunction compared to combined therapy of metformin and atorvastatin in diabetic hyperlipidemic rats. The median lethal dose of bee venom was estimated, and then 50 adult male albino rats were categorized into five groups. One group was fed a standard diet and served as a negative control, while the other groups were given nicotinamide and streptozotocin injections to induce type 2 diabetes. After confirming diabetes, the rats were fed a high-fat diet for four weeks. The four groups were divided as follows: one group served as a positive control, whereas the other three groups were treated with bee venom (0.5 mg/kg), bee venom (1.23 mg/kg), and combined therapy of metformin (60 mg/kg) and atorvastatin (10 mg/kg), respectively, for four weeks. Upon termination of the experiment, blood samples and heart tissue were obtained. Administration of bee venom using both doses (0.5 and 1.23 mg/kg) and combined therapy of metformin and atorvastatin revealed a significant decrease in the concentrations of glucose, total cholesterol, triacylglycerol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, troponin I, creatine kinase, and lactate dehydrogenase activities. Moreover, a significant decrease had been detedcted in malondialdehyde, nuclear factor-kappa-β levels, and relative mRNA expression of vascular cell adhesion molecule-1 and galectin-3 in heart tissue compared to the positive control (P < 0.0001). Furthermore, there was a significant increase in bodyweight levels of insulin, high-density lipoprotein cholesterol, and total antioxidant capacity in heart tissue compared to the positive control (P < 0.0001). The results indicate that bee venom can ameliorate cardiac dysfunction through attenuating oxidative stress and downregulating the NF-κβ signaling pathway.

Inhibitory Effect of Fisetin on α-Glucosidase Activity: Kinetic and Molecular Docking Studies

The inhibition of α-glucosidase is a clinical strategy for the treatment of type 2 diabetes mellitus (T2DM), and many natural plant ingredients have been reported to be effective in alleviating hyperglycemia by inhibiting α-glucosidase. In this study, the α-glucosidase inhibitory activity of fisetin extracted from Cotinus coggygria Scop. was evaluated in vitro. The results showed that fisetin exhibited strong inhibitory activity with an IC₅₀ value of 4.099 × 10⁻⁴ mM. Enzyme kinetic analysis revealed that fisetin is a non-competitive inhibitor of α-glucosidase, with an inhibition constant value of 0.01065 ± 0.003255 mM. Moreover, fluorescence spectrometric measurements indicated the presence of only one binding site between fisetin and α-glucosidase, with a binding constant (lgKa) of 5.896 L·mol⁻¹. Further molecular docking studies were performed to evaluate the interaction of fisetin with several residues close to the inactive site of α-glucosidase. These studies showed that the structure of the complex was maintained by Pi-Sigma and Pi-Pi stacked interactions. These findings illustrate that fisetin extracted from Cotinus coggygria Scop. is a promising therapeutic agent for the treatment of T2DM.