Role of Oxidative Stress in Pancreatic β-Cell Dysfunction

Hydrocotyle umbellata L.; a natural source of bioactives to mitigate diabetes mellitus and its complications

Metabolomics study of Hydrocotyle umbellata L. revealed the richness of its aerial parts in phenolics primarily; quercetin and its glycoside derivatives, which are well-reported to exert antidiabetic activity owing to their powerful antioxidant capacity. Hence, the antioxidant and antidiabetic potentials of the quercetin standardized ethanolic extract of H. umbellata aerial parts were investigated. The antioxidant activity was examined by using in-vitro 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay, while the antidiabetic activity was examined by using in-vitro α-glucosidase inhibitory assay and further confirmed by in-vivo experiments using streptozotocin-induced diabetes in rat model. Interestingly, the standardized ethanolic extract showed significant in-vitro antioxidant activity, and effectively inhibited Saccharomyces cerevisiae α-glucosidase enzyme activity. Moreover, it significantly reduced fasting blood glucose, triglycerides, and cholesterol levels. Thus, H. umbellata is a potential natural candidate to attenuate diabetes mellitus and its altered lipid profile complications, which could be attributed to its quercetin and quercetin glycosides content.

Scopoletin protects INS-1 pancreatic β cells from glucotoxicity by reducing oxidative stress and apoptosis

This study investigated whether scopoletin could protect INS-1 pancreatic β cells from apoptosis and oxidative stress caused by high glucose. Cells were pretreated with glucose (5.5 or 30 mM) and then treated with 0, 5, 10, 25, or 50 μM Scopoletin. Cell viability and insulin secretion were measured in addition to ROS, TBARS, NO and antioxidant enzymes. Western blot analysis and flow cytometric assessment of apoptosis were also carried out. High glucose of 30 mM caused glucotoxicity and cell death in INS-1 pancreatic β cells. However, 5, 10, 25 or 50 μM scopoletin increased the level of cell viability as concentrations increased. The levels of ROS, TBARS, and NO increased by high glucose were significantly decreased after scopoletin treatment. Scopoletin also raised antioxidant enzyme activities up against oxidative stress produced by high glucose. These effects influenced the apoptosis pathway, raising levels of anti-apoptotic protein, Bcl-2, and reducing levels of pro-apoptotic proteins, including JNK, Bax, cytochrome C, and caspase 9. Annexin V/propidium staining indicated that scopoletin significantly lowered high glucose-produced apoptosis. These results indicate that scopoletin can protect INS-1 pancreatic β cells from glucotoxicity caused by high glucose and have potential as a pharmaceutical material to protect the pancreatic β cells.

Protective Effects of Imeglimin and Metformin Combination Therapy on β-Cells in db/db Male Mice

Imeglimin and metformin act in metabolic organs, including β-cells, via different mechanisms. In the present study, we investigated the impacts of imeglimin, metformin, or their combination (Imeg + Met) on β-cells, the liver, and adipose tissues in db/db mice. Imeglimin, metformin, or Imeg + Met treatment had no significant effects on glucose tolerance, insulin sensitivity, respiratory exchange ratio, or locomotor activity in db/db mice. The responsiveness of insulin secretion to glucose was recovered by Imeg + Met treatment. Furthermore, Imeg + Met treatment increased β-cell mass by enhancing β-cell proliferation and ameliorating β-cell apoptosis in db/db mice. Hepatic steatosis, the morphology of adipocytes, adiposity assessed by computed tomography, and the expression of genes related to glucose or lipid metabolism and inflammation in the liver and fat tissues showed no notable differences in db/db mice. Global gene expression analysis of isolated islets indicated that the genes related to regulation of cell population proliferation and negative regulation of cell death were enriched by Imeg + Met treatment in db/db islets. In vitro culture experiments confirmed the protective effects of Imeg + Met against β-cell apoptosis. The expression of Snai1, Tnfrsf18, Pdcd1, Mmp9, Ccr7, Egr3, and Cxcl12, some of which have been linked to apoptosis, in db/db islets was attenuated by Imeg + Met. Treatment of a β-cell line with Imeg + Met prevented apoptosis induced by hydrogen peroxide or palmitate. Thus, the combination of imeglimin and metformin is beneficial for the maintenance of β-cell mass in db/db mice, probably through direct action on β-cells, suggesting a potential strategy for protecting β-cells in the treatment of type 2 diabetes.

Redox Balance in Type 2 Diabetes: Therapeutic Potential and the Challenge of Antioxidant-Based Therapy

Oxidative stress is an important factor in the development of type 2 diabetes (T2D) and associated complications. Unfortunately, most clinical studies have failed to provide sufficient evidence regarding the benefits of antioxidants (AOXs) in treating this disease. Based on the known complexity of reactive oxygen species (ROS) functions in both the physiology and pathophysiology of glucose homeostasis, it is suggested that inappropriate dosing leads to the failure of AOXs in T2D treatment. To support this hypothesis, the role of oxidative stress in the pathophysiology of T2D is described, together with a summary of the evidence for the failure of AOXs in the management of diabetes. A comparison of preclinical and clinical studies indicates that suboptimal dosing of AOXs might explain the lack of benefits of AOXs. Conversely, the possibility that glycemic control might be adversely affected by excess AOXs is also considered, based on the role of ROS in insulin signaling. We suggest that AOX therapy should be given in a personalized manner according to the need, which is the presence and severity of oxidative stress. With the development of gold-standard biomarkers for oxidative stress, optimization of AOX therapy may be achieved to maximize the therapeutic potential of these agents.

Composite biscuits from sandpaper and acha flour restore the altered activity of arginase, cholinergic, and purinergic enzymes in hypertensive-diabetic rats

Hypertension is one of the common co-morbidities in diabetes. Thus, the present study sought to study the effects of composite biscuits from the mixture of acha (Digitaria exilis) and sandpaper (Fiscus exasperata) leaf flours (ASLF) on mean arterial blood pressure (MABP), arginase, cholinergic, purinergic enzymatic cascade, and nitric oxide (NO) levels as well as oxidative status in streptozotocin (STZ)/L-N^G -nitro arginine methyl ester (L-NAME)-induced hypertensive/diabetic rats. Experimental rats were distributed randomly into 7 groups (n = 5). Group I-III rats were placed on the basal diet; IV-VII rats were placed on composite biscuits designated as A, B, C, and D respectively for 14 days. On the 13th day, the MABP of the experimental rats was monitored and recorded. Thereafter, the rats were sacrificed, tissues of interest were harvested, and homogenized. Subsequently, the activity of arginase cholinesterase and purinergic enzymes, as well as NO levels were evaluated in the experimental rats. However, hypertensive/diabetic rats placed on the formulated diet exhibited reduced MABP when compared with the untreated hypertensive/diabetic rats. Also, altered activity of arginase, cholinergic and purinergic were restored in diet-treated hypertensive/diabetic rats when compared with hypertensive/diabetic rats. Similarly, the NO level and antioxidant status of the treated hypertensive/diabetic rats were notably enhanced when compared with hypertensive/diabetic rats. It could be inferred that composite biscuits exhibited an ameliorative effect in hypertensive/diabetic states via their reductive effect on the MABP, arginase, cholinesterase, and purinergic enzymes and enhanced NO levels in hypertensive/diabetic rats. Meanwhile, the biscuit designated as D had seems better when their effects were compared holistically. PRACTICAL APPLICATIONS: Acha grains and sandpaper leaf have been used in the folklore for disease treatment. However, the production of composite biscuits from these naturally available recipes for the management of hypertensive diabetics proved therapeutic since their effect on hypertensive diabetic rats is positive. Therefore, the composite biscuit will offer nutraceutical benefits to both healthy and disease individuals.

Dendrobium mixture improves gestational diabetes mellitus through regulating Nrf2/HO1 signaling pathway

BACKGROUND

Gestational diabetes mellitus (GDM) is characterized by insulin resistance during pregnancy, and it is always combined with serious complications. Dendrobium mixture (DMix) is a kind of traditional Chinese medicine, and it has been proved to be an effective treatment for diabetes. However, the regulatory role of DMix in GDM remains elusive.

METHODS

High fat feed combined with streptozotocin injection and high glucose medium were used to establish GDM animal and cell models, respectively. The levels of blood glucose, blood lipid, and insulin were measured with commercial kits. Western blotting was used to detect protein expression.

RESULTS

DMix improved pancreas and placenta injury in GDM rats. DMix reversed the influence of GDM on the levels of SOD, MDA, and glutathione in the serum. Hyperglycemia and hyperlipidemia in GDM rats were suppressed by DMix. The activation of MAPK and inhibition of Nrf2/HO1 in GDM animal and cell models were reversed by DMix. The increase of ROS intensity, apoptosis, and inflammation factors in HG treated cells were reversed by DMix.

CONCLUSION

This research proved that DMix improved GDM through inhibiting oxidative condition, inflammation factors, hyperglycemia and hyperlipidemia. This study might provide a novel thought for the prevention and treatment of GDM.

A Review of CRISPR Cas9 for Alzheimer’s Disease: Treatment Strategies and Could target APOE e4, APP, and PSEN-1 Gene using CRISPR cas9 Prevent the Patient from Alzheimer’s Disease?

   A Review of CRISPR Cas9 for Alzheimer’s Disease: Treatment Strategies and Could target APOE e4, APP, and PSEN-1 Gene using CRISPR cas9 Prevent the Patient from Alzheimer’s Disease? BACKGROUND: Alzheimer’s disease is a neurodegenerative disorder characterized by the formation of β-amyloid plaques and neurofibrillary tangles from hyperphosphorylated tau. Several studies suggest that targeting the deletion of the APOE e4, PSEN-1, and APP will reduce tau phosphorylation and Aβ protein accumulation, a crucial hypothesis for the causation of Alzheimer’s disease. APOE e4, PSEN-1, and APP with genome editing Clustered Regular interspersed Short Palindromic Repeats-CRISPR-related (CRISPR/Cas9) are thought to have therapeutic promise for Alzheimer’s disease.AIM: The purpose of this study was to determine whether targeting APOE e4, PSEN-1, and APP using CRISPR/Cas9 is an effective therapeutic and whether it has a long-term effect on Alzheimer’s disease.METHODS: The method used in this study summarized articles by examining the titles and abstracts of specific specified keywords. In this situation, the author picked the title and abstract that matched PubMed, Google Scholar, Science Direct, Cochrane, and the Frontiers in Neuroscience; this was followed by checking to see whether the paper was available in full-text. Eventually, the researcher will study the entire article to decide if it is valuable and relevant to the issue.RESULTS: CRISPR/Cas9 deletion of APOE e4, PSEN-1, and APP in induced pluripotent stem cells (iPSC’s) and g2576 mice as APP mutant models reduce tau phosphorylation and Aβ protein accumulation from neurofibrillary tangles and prevent cell death, vascular damage, and dementia. Furthermore, CRISPR/Cas9 deletion in APOE e4, PSEN-1, and APP improved neuronal cell resilience to oxidative stress and inflammation.CONCLUSION: APOE e4, PSEN-1, and APP deletion by genome editing CRISPR/Cas9 is effective to reduce tau phosphorylation and Aβ protein accumulation from neurofibrillary tangles, cell death, vascular damage, and dementia. However, further research is needed to determine the side effects and safety of its use.

The Promising Role of Microbiome Therapy on Biomarkers of Inflammation and Oxidative Stress in Type 2 Diabetes: A Systematic and Narrative Review

Background

One in 10 adults suffer from type 2 diabetes (T2D). The role of the gut microbiome, its homeostasis, and dysbiosis has been investigated with success in the pathogenesis as well as treatment of T2D. There is an increasing volume of literature reporting interventions of pro-, pre-, and synbiotics on T2D patients.

Methods

Studies investigating the effect of pro-, pre-, and synbiotics on biomarkers of inflammation and oxidative stress in T2D populations were extracted from databases such as PubMed, Scopus, Web of Science, Embase, and Cochrane from inception to January 2022.

Results

From an initial screening of 5,984 hits, 47 clinical studies were included. Both statistically significant and non-significant results have been compiled, analyzed, and discussed. We have found various promising pro-, pre-, and synbiotic formulations. Of these, multistrain/multispecies probiotics are found to be more effective than monostrain interventions. Additionally, our findings show resistant dextrin to be the most promising prebiotic, followed closely by inulin and oligosaccharides. Finally, we report that synbiotics have shown excellent effect on markers of oxidative stress and antioxidant enzymes. We further discuss the role of metabolites in the resulting effects in biomarkers and ultimately pathogenesis of T2D, bring attention toward the ability of such nutraceuticals to have significant role in COVID-19 therapy, and finally discuss few ongoing clinical trials and prospects.

Conclusion

Current literature of pro-, pre- and synbiotic administration for T2D therapy is promising and shows many significant results with respect to most markers of inflammation and oxidative stress.

Second Sphere Interactions in Amyloidogenic Diseases

Amyloids are protein aggregates bearing a highly ordered cross β structural motif, which may be functional but are mostly pathogenic. Their formation, deposition in tissues and consequent organ dysfunction is the central event in amyloidogenic diseases. Such protein aggregation may be brought about by conformational changes, and much attention has been directed toward factors like metal binding, post-translational modifications, mutations of protein etc., which eventually affect the reactivity and cytotoxicity of the associated proteins. Over the past decade, a global effort from different groups working on these misfolded/unfolded proteins/peptides has revealed that the amino acid residues in the second coordination sphere of the active sites of amyloidogenic proteins/peptides cause changes in H-bonding pattern or protein-protein interactions, which dramatically alter the structure and reactivity of these proteins/peptides. These second sphere effects not only determine the binding of transition metals and cofactors, which define the pathology of some of these diseases, but also change the mechanism of redox reactions catalyzed by these proteins/peptides and form the basis of oxidative damage associated with these amyloidogenic diseases. The present review seeks to discuss such second sphere modifications and their ramifications in the etiopathology of some representative amyloidogenic diseases like Alzheimer's disease (AD), type 2 diabetes mellitus (T2Dm), Parkinson's disease (PD), Huntington's disease (HD), and prion diseases.

Association of sickle cell trait with β-cell dysfunction and physical activity in adults living with and without HIV in Tanzania

This study aimed to investigate sickle cell trait (SCT) associations with physical activity, markers of insulin secretion and resistance, and glucose among people living with HIV infection (PLWH), both antiretroviral therapy (ART) naive and experienced, and HIV-uninfected adults. This was a cross-sectional study conducted in Mwanza, Northwestern Tanzania. We used data of 668 participants attained from two sub-studies of CICADA study. Mean age was 40 (SD 11.5) years, 402 (61.7%) were females and 157 (24.1%) had SCT. PLWH were 422 (64.7%), of these, 80 (18.9%) were on ART. People with SCT had higher risk of having an isolated β-cell dysfunction compared to those without SCT (RRR = 1.82, CI: 1.10, 3.01, p = 0.02). People with SCT but without HIV infection had lower average acceleration on the trunk longitudinal axis (ACCx) and higher level of self-reported physical activity. 30 min oral glucose tolerance test among PLWH on ART was higher in those with SCT compared to those without SCT. People with SCT are at higher risk of having β-cell dysfunction and those with SCT on ART are at more risk of developing diabetes. Future studies to investigate the interaction between SCT and HIV/ART on risk of diabetes should be considered.

The ability of deep eutectic solvent systems to extract bioactive compounds from apple pomace

The objective of this study was to examine the bioactivity of extracts from apple pomace obtained by non-conventional green extraction methods (DES systems). Bioactivity was antioxidant capacity and ability to stimulate insulin secretion from pancreatic beta-cells. The antioxidant capacity of extracts was examined using the DPPH and the FRAP assay. Impact of the extracts on cell viability and insulin secretion were examined using the BRIN-BD11 cell line. ChCl:EG(1:4) extracts resulted in high antioxidant capacity in the DPPH assay (80.1% inhibition versus 11.3%). Extracts obtained from the classical systems demonstrated an ability to promote insulin secretion significantly higher than the positive control, p < 0.05. ChCl:EG(1:4) extracts stimulated insulin secretion to a lesser extent. Overall, the data provides evidence for the potential of DES systems to extract bioactive compounds from apple pomace that have relevance for metabolic health. Further optimisation of the extraction procedures should be tailored to the desired bioactive properties.

Exenatide improves antioxidant capacity and reduces the expression of LDL receptors and PCSK9 in human insulin-secreting 1.1E7 cell line subjected to hyperglycemia and oxidative stress

Introduction

GLP-1 receptor agonists (e.g., exenatide) are novel drugs used in the treatment of diabetes. These drugs, working with other mechanisms of action, improve glycemic control by increasing secretion of insulin and improving survival of pancreatic islet beta cells. Alterations in the oxidative stress level or the expression of proteins associated with cholesterol uptake might be responsible for those findings. Currently, there are few in vitro studies on the impact of exenatide antioxidant capacity in human islet beta cell lines and none that assess the influence of exenatide on LDL receptors and PCSK9 under hyperglycemia and oxidative stress. Therefore, we evaluated the impact of exenatide on antioxidant capacity, insulin secretion, and proteins involved in cholesterol metabolism.

Materials and Method

An in vitro culture of insulin-secreting cells 1.1E7 was subjected to hyperglycemia and oxidative stress. Assessment was made of the expression of enzymes associated with oxidative stress (NADPH oxidase, catalase, glutathione peroxidase, superoxide dismutase, iNOS) and cholesterol uptake (LDL receptors, PCSK9). Additionally, insulin and nitrite levels in culture media were quantified.

Results

We showed that exenatide improves expression of catalase and reduces the amount of nitrite in cell cultures in a protein kinase A–dependent manner. Those results were accompanied by a drop in the expression of LDL receptors and PCSK9. Insulin secretion was modestly increased in the culture condition.

Conclusions

Our findings show potential protective mechanisms exerted by exenatide in human insulin-secreting pancreatic beta cell line (1.1E7), which may be exerted through increased antioxidant capacity and reduced accumulation of cholesterol.

Divergent effects of HIV reverse transcriptase inhibitors on pancreatic beta-cell function and survival: Potential role of oxidative stress and mitochondrial dysfunction

Antiretroviral therapy (ART), a life-saving treatment strategy in HIV/AIDS, has been implicated in increasing the risk of type 2 diabetes mellitus (T2DM). Direct damaging effects on beta-cell function and survival by either non-nucleoside reverse transcriptase inhibitors (NNRTIs) or nucleoside/tide reverse transcriptase inhibitors (NRTIs) may predispose individuals to developing T2DM or if already type 2 diabetic, to insulin dependency. The aim of this study was to investigate the effects of the NNRTIs efavirenz, rilpivirine and doravirine, and the NRTIs tenofovir disoproxil fumarate and emtricitabine, on beta-cell function and survival while suggesting potential cellular and molecular mechanism(s). Our results show contrasting effects within the NNRTI class as doravirine did not cause damaging effects in the rat insulinoma INS-1E cells while efavirenz and rilpivirine reduced insulin release and cell viability, and induced apoptosis in INS-1E cells. Additionally, efavirenz and rilpivirine increased ROS generation, disrupted Δψm and upregulated the mRNA and protein expression of CHOP and GRP78, key markers of endoplasmic reticulum stress. In silico docking studies predict a possible inhibition of the mitochondrial ATP synthase by rilpivirine. On the contrary, both the NRTIs tenofovir disoproxil fumarate and emtricitabine did not affect GSIS, cell viability and apoptosis/necrosis levels in INS-1E cells. The deleterious effects observed in beta-cells exposed to efavirenz or rilpivirine may be, at least partially, mediated by oxidative stress and mitochondrial toxicity. These findings provide potential mechanism(s) by which efavirenz and rilpivirine may contribute to the pathogenesis of T2DM and the progression of T2DM to insulin dependency in HIV-infected type 2 diabetics.

Carnosine protects stimulus-secretion coupling through prevention of protein carbonyl adduction events in cells under metabolic stress

Type 2 diabetes is characterised by failure to control glucose homeostasis, with numerous diabetic complications attributable to the resulting exposure of cells and tissues to chronic elevated concentrations of glucose and fatty acids. This, in part, results from formation of advanced glycation and advanced lipidation end-products that are able to modify protein, lipid, or DNA structure, and disrupt normal cellular function. Herein we used mass spectrometry to identify proteins modified by two such adduction events in serum of individuals with obesity, type 2 diabetes, and gestational diabetes, along with similar analyses of human and mouse skeletal muscle cells and mouse pancreatic islets exposed to glucolipotoxic stress. We also report that carnosine, a histidine containing dipeptide, prevented 65-90% of 4-hydroxynonenal and 3-nitrotyrosine adduction events, and that this in turn preserved mitochondrial function and protected stimulus-secretion coupling in cells exposed to metabolic stress. Carnosine therefore offers significant therapeutic potential against metabolic diseases.

Fat mass and obesity-associated gene expression and disease severity in type 2 diabetes mellitus

Obesity and visceral adiposity are major risk factors for type 2 diabetes mellitus (T2DM). The fat mass and obesity-associated (FTO) gene is associated with increased risk of obesity and T2DM. The aim of this work was to study the association between FTO gene expression and serum FTO protein level with disease severity in T2DM patients.

PATIENTS AND METHODS

One hundred T2DM patients were divided into two equal groups according to diabetes control and complications and fifty healthy controls were included in this study. FTO messenger ribonucleic acid (mRNA) expression level was analyzed by Real time polymerase chain reaction (PCR) technique and serum level of FTO protein was measured by ELISA.

RESULTS

FTO gene expression and FTO protein levels were increased in the two T2DM groups compared to the control group with significant further increases in patients with severe disease. FTO gene expression and FTO protein levels were positively correlated with obesity, insulin resistance and blood glucose indices as well as the presence of diabetic complications. Regression analyses showed that FTO gene expression and FTO protein levels were risk factors for T2DM severity.

CONCLUSIONS

Increased FTO gene expression and its serum protein levels are associated with increased T2DM severity.

Clinical characteristics, gestational weight gain and pregnancy outcomes in women with a history of gestational diabetes mellitus

BACKGROUND

Pregnant women with a history of gestational diabetes mellitus (GDM) are at high risk of GDM. It is unclear whether this population has pregnancy characteristics different from the general population. Whether these features affect the perinatal outcome has not yet been elucidated.

METHODS

A retrospective study was conducted, including baseline characteristics, laboratory data, gestational weight gain (GWG), and pregnancy outcomes of 441 pregnant women with prior GDM. Besides, 1637 women without a history of GDM treated in the same period were randomly selected as the control group. The above indicators of the two groups were compared. Multivariable logistic regression analysis was performed to investigate how GWG was associated with perinatal outcomes for previous GDM women.

RESULTS

Among women with GDM history, triglycerides (TG) and fasting plasma glucose (FPG) in the 1st trimester were higher than those without GDM history. GWG was lower in women with prior GDM relative to the control group at various pregnancy stages. However, women with GDM history had a higher risk of developing GDM (OR 3.25, 95% CI 2.26-4.68) and pregnancy-induced hypertension (OR 1.50, 95% CI 1.05-2.45). In women with previous GDM, excessive GWG before OGTT exhibited a positive correlation with pregnancy-induced hypertension (OR 1.47, 95% CI 1.05-3.32), while inadequate GWG was not a protective factor for GDM and pregnancy-induced hypertension.

CONCLUSION

Women with prior GDM have glucose and lipid metabolism disorders in the 1st trimester. Limited reduction of GWG before oral glucose tolerance test (OGTT) was insufficient to offset the adverse effects of glucose and lipid metabolism disorders in women with previous GDM. Relevant interventions may be required at early stage or even before pregnancy.

Quercetin and metabolic syndrome: A review

Metabolic syndrome (MetS) is a complex of diseases that lead to mortality due to the development of cardiovascular problems. Quercetin, as an important flavonoid, has various properties such as decreasing blood pressure, anti-hyperlipidemia, anti-hyperglycemia, anti-oxidant, antiviral, anticancer, anti-inflammatory, anti-microbial, neuroprotective, and cardio-protective effects. In this review article, we collected original articles from different sources such as Google Scholar, Medline, Scopus, and Pubmed, which is related to the effect of quercetin on the improvement of the signs of MetS, including elevated glucose level, hyperlipidemia, obesity, and blood pressure. According to these data, quercetin may also have a role in the management of metabolic disorders via different mechanisms such as increasing adiponectin, decreasing leptin, anti-oxidant activity, reduction of insulin resistance, the elevation of insulin level, and blocking of calcium channel. We have attempted to make some recommendations on the quercetin application in patients. However, it needs to do further clinical trials and more investigations to show the real clinical value of quercetin on metabolic syndrome.

Anti-inflammatory effect of resveratrol attenuates the severity of diabetic neuropathy by activating the Nrf2 pathway

The mechanisms underlying the development of neuropathy associated with diabetes mellitus are not fully understood. Resveratrol, as a nonflavonoid polyphenol, plays a variety of beneficial roles in the treatment of chronic diseases such as Alzheimer's disease, coronary heart disease and obesity. In our study, the role of nuclear erythroid 2-related factor 2 (Nrf2) in resveratrol-mediated protection against streptozotocin-induced diabetic peripheral neuropathy (DPN) was investigated, and the antioxidant effect of resveratrol in diabetic peripheral nerves was studied. The STZ-treated model mice were divided into two groups. The resveratrol group was intragastrically administered 10 ml/kg 10% resveratrol once a day until the 12th week after STZ injection. The vehicle-treated mice were injected with the same volume of DMSO. Analysis of the effects of resveratrol in DPN revealed the following novel findings: (i) the pain and temperature sensitivities of diabetic mice were improved after treatment with resveratrol; (ii) Nrf2 expression was increased in the diabetic peripheral nerves of resveratrol-treated mice, and NF-KB pathway inhibition protected nerves upon resveratrol treatment in peripheral neuropathy; and (iii) resveratrol modulated the anti-inflammatory microenvironment of peripheral nerves by increasing Nrf2 activation and the expression of p-p65, and these changes may have been responsible for the neuroprotective effect of resveratrol in DPN, which was confirmed by Nrf2 knockout in diabetic mice. Overall, this study demonstrates that resveratrol may attenuate the severity of DPN by protecting peripheral nerves from apoptosis by inhibiting the NF-KB pathway and increasing Nrf2 expression.

Nifuroxazide improves insulin secretion and attenuates high glucose-induced inflammation and apoptosis in INS-1 cells

Inflammation and oxidative stress are important factors that cause islet β-cell dysfunction. STAT3 is not only a major factor in cell proliferation and differentiation, but also plays an important role in mediating inflammation. As a potent inhibitor of STAT3, the effect of Nifuroxazide (Nifu) on pancreatic islet cells in a high glucose environment has not been reported. In the present study, we used high concentration glucose-induced INS-1 cells to examine the effects of Nifu on high glucose-induced cell function by glucose-stimulated insulin secretion (GSIS). The effects of Nifu on high glucose-induced oxidative stress were recorded by oxidative factors and antioxidant factors. Simultaneously, the effect of Nifu on the inflammatory response, apoptosis, and STAT3/SOCS3 signal pathway were validated by quantitative real-time PCR (qRT-PCR) and Western blot. Our study indicated that Nifu significantly improved cell vitality and insulin secretion of INS-1 cells induced by high glucose. We found Nifu significantly inhibited pro-oxidative factors (ROS, MDA) and promoted anti-oxidative factors (SOD, GSH-PX, CAT). Meanwhile, qRT-PCR and Western blot results showed that inflammatory and apoptosis factors were remarkably inhibited by Nifu. Further research indicated that Nifu clearly suppressed the activation of the STAT3/SOCS3 signaling pathway. In conclusion, Nifu can significantly improve the insulin secretion function, protect oxidative stress injury, and reduce inflammatory response and apoptosis in high glucose-induced INS-1 cells. Therefore, Nifu has a new positive effect on maintaining the normal function of pancreatic islet cells in a high glucose environment and provides new drug candidates for the treatment and prevention of diabetes.

Angiotensin-Converting-Enzyme 2 and Renin-Angiotensin System Inhibitors in COVID-19: An Update

Ever since its outbreak, Corona Virus Disease 2019(COVID-19) caused by SARS-CoV-2 has affected more than 26 million individuals in more than 200 countries. Although the mortality rate of COVID-19 is low, but several clinical studies showed, patients with diabetes mellitus (DM) or other major complication at high risk of COVID-19 and reported more severe disease and increased fatality. The angiotensin-converting-enzyme 2 (ACE2), a component of renin-angiotensin-system (RAS); acts on ACE/Ang-II/AT1recptor axis, and regulates pathological processes like hypertension, cardiac dysfunction, Acute Respiratory Distress Syndrome (ARDS) etc. The progression of T2DM and hypertension show decreased expression and activity of ACE2. There are several treatment strategies for controlling diabetes, hypertension, etc; like ACE2 gene therapies, endogenous ACE2 activators, human recombinant ACE2 (hrACE2), Angiotensin-II receptor blockers (ARBs) and ACE inhibitors (ACEi) medications. ACE2, the receptors for SARS-CoV2, facilitates virus entry inside host cell. Clinicians are using two classes of medications for the treatment of COVID-19; one targets the SARS-CoV-2-ACE2 interaction, while other targets human immune system. The aim of this review is to discuss the role of ACE2 in diabetes and in COVID-19 and to provide an analysis of data proposing harm and benefit of RAS inhibitor treatment in COVID-19 infection as well as showing no association whatsoever. This review also highlights some candidate vaccines which are undergoing clinical trials.

Ionizing radiation-induced circulatory and metabolic diseases

Risks to health are the prime consideration in all human situations of ionizing radiation exposure and therefore of relevance to radiation protection in all occupational, medical, and public exposure situations. Over the past few decades, advances in therapeutic strategies have led to significant improvements in cancer survival rates. However, a wide range of long-term complications have been reported in cancer survivors, in particular circulatory diseases and their major risk factors, metabolic diseases. However, at lower levels of exposure, the evidence is less clear. Under real-life exposure scenarios, including radiotherapy, radiation effects in the whole organism will be determined mainly by the response of normal tissues receiving relatively low doses, and will be mediated and moderated by systemic effects. Therefore, there is an urgent need for further research on the impact of low-dose radiation. In this article, we review radiation-associated risks of circulatory and metabolic diseases in clinical, occupational or environmental exposure situations, addressing epidemiological, biological, risk modelling, and systems biology aspects, highlight the gaps in knowledge and discuss future directions to address these gaps.

Flavonoids Identification and Pancreatic Beta-Cell Protective Effect of Lotus Seedpod

Oxidative stress is highly associated with the development of diabetes mellitus (DM), especially pancreatic beta-cell injury. Flavonoids derived from plants have caused important attention in the prevention or treatment of DM. Lotus seedpod belongs to a traditional Chinese herbal medicine and has been indicated to possess antioxidant, anti-age, anti-glycative, and hepatoprotective activities. The purpose of this study was to demonstrate the pancreatic beta-cell protective effects of lotus seedpod aqueous extracts (LSE) against oxidative injury. According to HPLC/ESI-MS-MS method, LSE was confirmed to have flavonoids derivatives, especially quercetin-3-glucuronide (Q3G). In vitro, LSE dose-dependently improved the survival and function of rat pancreatic beta-cells (RIN-m5F) from hydrogen peroxide (H₂O₂)-mediated loss of cell viability, impairment of insulin secretion, and promotion of oxidative stress. LSE showed potential in decreasing the H₂O₂-induced occurrence of apoptosis. In addition, H₂O₂-triggered acidic vesicular organelle formation and microtubule-associated protein light chain 3 (LC3)-II upregulation, markers of autophagy, were increased by LSE. Molecular data explored that antiapoptotic and autophagic effects of LSE, comparable to that of Q3G, might receptively be mediated via phospho-Bcl-2-associated death promoter (p-Bad)/B-cell lymphoma 2 (Bcl-2) and class III phosphatidylinositol-3 kinase (PI3K)/LC3-II signal pathway. In vivo, LSE improved the DM symptoms and pancreatic cell injury better than metformin, a drug that is routinely prescribed to treat DM. These data implied that LSE induces the autophagic signaling, leading to protect beta-cells from oxidative stress-related apoptosis and injury.

Relationship between Decreased Serum Superoxide Dismutase Activity and Metabolic Syndrome: Synergistic Mediating Role of Insulin Resistance and β-Cell Dysfunction

The interplays of cellular aging and oxidative stress (OS) markers form a complex network, which has been reported to be interrelated with numerous age-related and metabolic diseases, including metabolic syndrome (MS). However, given the multifactorial mechanisms of MS, several important confounders such as dietary factors and the reciprocal effect among these markers have not been considered and adjusted in previous investigations regarding the associations of cellular aging and OS markers with MS and its related metabolic abnormalities. To explicate this, we conducted a cross-sectional study among 533 Chinese adults. All the participants underwent a 75 g oral glucose tolerance test. Dietary data were collected via a 24-hour dietary recall and subsequently analyzed by a registered dietitian using nutrition calculation software. Clinical diagnosis of MS was made according to the revised National Cholesterol Education Program Adult Treatment Panel III criteria (2004) with waist circumference cutoff modified for an Asian population. The leukocyte telomere length, mitochondrial DNA copy number, 8-hydroxy-2-deoxyguanosine, superoxide dismutase (SOD) activity, and glutathione reductase were examined. SOD activity was significantly decreased in MS subjects (62.06 ± 16.89 U/mL vs. 56.25 ± 22.61 U/mL, P = 0.001) and exhibited a descending trend across sequential increase of MS component number (P for trend = 0.031). SOD activity is modestly correlated with glucose indicators and insulin sensitivity and β-cell function indices and was independently and negatively correlated with the level of triglyceride. An independent association between SOD activity and MS was observed after adjusting for metabolic indicators, dietary factors, cellular aging, and OS markers, as well as insulin sensitivity and β-cell function indices. However, the statistical significance of the association between SOD activity and MS was attenuated after adjusting for the Matsuda insulin sensitivity index (ISIM) and insulin secretion-sensitivity index-2 (ISSI-2), suggesting a possible mediating effect. Therefore, we conducted a mediation model analysis, which showed that decreased ISIM and ISSI-2 partially and synergistically mediated the contribution of decreased SOD activity to MS. In conclusion, decreased SOD activity is an independent predictor for increased risk of MS, and insulin resistance and β-cell dysfunction partially mediate the relationship between decreased SOD activity and MS.

Triglyceride is independently correlated with insulin resistance and islet beta cell function: a study in population with different glucose and lipid metabolism states

BACKGROUND

Previous studies on the effects of lipotoxicity and oxidative stress on islet beta cell function mainly focused on patients with diabetes, whereas studies on normal glucose tolerance (NGT) are few. The aim of this study was to explore the relationships among triglyceride (TG), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), oxidative stress indicators, insulin resistance, and beta cell function in populations with different glucose and lipid metabolism states.

METHODS

A total of 517 individuals were recruited from a rural community in Beijing, China. Glucose metabolism status was defined according to the results of a 75-g oral glucose tolerance test (OGTT). Dyslipidemia was defined as abnormal TG, HDL-c, or LDL-c levels. The population was divided into four groups: individuals with normal glucose and lipid levels (group A, n = 62); those with dyslipidemia alone (group B, n = 82); those with dysglycemia alone (group C, n = 121); and those with dysglycemia and dyslipidemia (group D, n = 247). Oxidative stress indicators, including superoxide dismutase (SOD), glutathione reductase (GR) and 8-hydroxydeoxyguanosine (8-OHdG), were measured. Homeostasis model assessment of insulin resistance (HOMA-IR) and glucose disposition index (DI₃₀, DI₁₂₀) were calculated to assess insulin resistance and islet beta cell function, respectively. Stratified multiple linear regression analysis was used to explore relationships between TG, HDL-c, LDL-c, oxidative stress indicators, and insulin resistance (natural log transformation of HOMA-IR, LnHOMA-IR) and beta cell function (natural log transformation of DI₃₀, Ln DI₃₀).

RESULTS

Compared with the control group, populations with dyslipidemia and/or dysglycemia showed significantly increased insulin resistance. Dyslipidemia aggravated insulin resistance and beta cell dysfunction in individuals with dysglycemia. Stratified regression analysis showed that TG positively correlated with LnHOMA-IR in individuals with normal glucose levels (beta = 0.321, 0.327, P = 0.011, 0.003 in groups A and B, respectively) and negatively correlated with LnDI₃₀ in participants with dyslipidemia (beta = - 0.225, - 0.122, P = 0.035, 0.048 in groups B and D, respectively). Reduced serum SOD levels in individuals with dysglycemia plus dyslipidemia were observed, and a negative association between TG and SOD levels was found (r = - 0.461, P < 0.001).

CONCLUSION

TG correlated with both insulin resistance and beta cell function in individuals with dyslipidemia alone. SOD negatively correlated with TG, indicating a close relationship between oxidative stress and glucose-lipid metabolism. Due to the adverse effect of hypertriglyceridemia on insulin sensitivity and islet beta cell function, more attention should be paid to the detection and management of hypertriglyceridemia.

Anti-diabetic activity of crude polysaccharide and rhamnose-enriched polysaccharide from G. lithophila on Streptozotocin (STZ)-induced in Wistar rats

The aim of the present study was to elucidate the anti-diabetic effects of the crude polysaccharide and rhamnose-enriched polysaccharide derived from G. lithophila on streptozotocin (STZ)-induced diabetic Wistar rats. Treatment with crude polysaccharide and rhamnose-enriched polysaccharide showed increases in body weight and pancreatic insulin levels and a decrease in blood glucose levels compared with control diabetic rats. The blood concentrations of total cholesterol (TC), triglycerides (TGs), low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) decreased, and high-density lipoprotein (HDL) increased both in the crude polysaccharide- and rhamnose-enriched polysaccharide-treated rats. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels increased, and malondialdehyde (MDA) levels decreased in the livers, kidneys and pancreases of crude polysaccharide- and rhamnose-enriched polysaccharide-treated rats. Immunohistological examination further confirmed that restoration of the normal cellular size of the islets of Langerhans and the rebirth of β-cells were found to be greater in the body region than in the head and tail regions of the pancreas. The crude polysaccharide- and rhamnose-enriched polysaccharide-treated diabetic rats showed normal blood glucose levels and insulin production, and reversed cholesterol levels and enzymatic actions. Therefore, rhamnose-enriched polysaccharide from G. lithophila acts as a potent anti-diabetic agent to treat diabetes and can lead to the development of an alternative medicine for diabetes in the future.

Increased double strand breaks in diabetic β-cells with a p21 response that limits apoptosis

DNA damage and DNA damage response (DDR) pathways in β-cells have received little attention especially in the context of type-2 diabetes. We postulate that p21 plays a key role in DDR by preventing apoptosis, associated through its overexpression triggered by DNA stand breaks (DSBs). Our results show that β-cells from chronic diabetic mice had a greater extent of DSBs as compared to their non-diabetic counterparts. Comet assays and nuclear presence of γH2AX and 53bp1 revealed increased DNA DSBs in 16 weeks old (wo) db/db β-cells as compared to age matched non-diabetic β-cells. Our study of gene expression changes in MIN6 cell line with doxorubicin (Dox) induced DNA damage, showed that the DDR was similar to primary β-cells from diabetic mice. There was significant overexpression of DDR genes, gadd45a and p21 after a 24-hr treatment. Western blot analysis revealed increased cleaved caspase3 over time, suggesting higher frequency of apoptosis due to Dox-induced DNA strand breaks. Inhibition of p21 by pharmacological inhibitor UC2288 under DNA damage conditions (both in Dox-induced MIN6 cells and older db/db islets) significantly increased the incidence of β-cell apoptosis. Our studies confirmed that while DNA damage, specifically DSBs, induced p21 overexpression in β-cells and triggered the p53/p21 cellular response, p21 inhibition exacerbated the frequency of apoptosis.

Targeting microRNAs as a Therapeutic Strategy to Reduce Oxidative Stress in Diabetes

Diabetes mellitus is a group of heterogeneous metabolic disorders characterized by chronic hyperglycaemia as a consequence of pancreatic β cell loss and/or dysfunction, also caused by oxidative stress. The molecular mechanisms involved inβ cell dysfunction and in response to oxidative stress are also regulated by microRNAs (miRNAs). miRNAs are a class of negative gene regulators, which modulate pathologic mechanisms occurring in diabetes and its complications. Although several pharmacological therapies specifically targeting miRNAs have already been developed and brought to the clinic, most previous miRNA-based drug delivery methods were unable to target a specific miRNA in a single cell type or tissue, leading to important off-target effects. In order to overcome these issues, aptamers and nanoparticles have been described as non-cytotoxic vehicles for miRNA-based drug delivery. These approaches could represent an innovative way to specifically target and modulate miRNAs involved in oxidative stress in diabetes and its complications. Therefore, the aims of this review are: (i) to report the role of miRNAs involved in oxidative stress in diabetes as promising therapeutic targets; (ii) to shed light onto the new delivery strategies developed to modulate the expression of miRNAs in diseases.

Role of edible mushroom as a potent therapeutics for the diabetes and obesity

Diabetes and obesity are the most frequently found disease worldwide. Several factors are responsible for obesity, i.e., imbalance in energy expenditure, environmental factors, feeding habit, lifestyle, etc., which can also be responsible for type 2 diabetes mellitus. There are several synthetic drugs available to combat these diseases which have some side effects on sufferers. Therefore, people are shifting towards inexpensive, effective, widely available natural and herbal medicines. Edible mushrooms, which have been used from ancient time to cure these diseases, contain anti-oxidant, fibers, triterpenoids, alkaloid, and other phytochemicals. Comatin, β-glucan, Tremellastin, and Lentinan KS-2 are active chemicals of mushrooms which show great effect on diabetes mellitus and obesity by modulating either cellular function or biochemical pathways. Here, in this review, we have discussed the potential role of edible mushrooms and its biochemicals in control of diabetes and obesity. Using Bioinformatics, we can find the specific targets of theses biochemicals, so that these can be more effective.

Ethanolic extract and ethyl acetate fraction of Coutoubea spicata attenuate hyperglycemia, oxidative stress, and muscle damage in alloxan-induced diabetic rats subjected to resistance exercise training program

Gentianaceae family (such as Coutoubea spicata) contains iridoids and flavonoids with antidiabetic properties. However, there is no information available about the antidiabetic effects of C. spicata when combined with resistance exercise training (RET). This study evaluated the effects of the ethanolic extract (EE) and ethyl acetate fraction (EAF) of C. spicata on biochemical markers, muscle damage, and oxidative stress in diabetic rats submitted to RET. Alloxan-induced diabetic rats were distributed into 4 groups (each group, n = 8) treated with distilled water (TD), EE, EAF, or metformin and submitted to RET. Two groups without the disease (each group, n = 8) (sedentary control and trained control), as well as a sedentary diabetic group (n = 8) were included. Body weight and glycemia were evaluated weekly. After 30 days, lipid/lipoprotein profile, aspartate aminotransferase, alanine aminotransferase, muscle damage ((creatine kinase (CK) and lactate dehydrogenase (LDH)), and oxidative stress (malondialdehyde (MDA), sulfhydryl groups (SH), and ferric reducing antioxidant power) were evaluated. MDA and SH for pancreas, liver, heart, and muscle were evaluated. C. spicata extract and fraction combined with RET recovered body weight and reduced glycemia, muscle damage (CK: 36.83% and 21.45%; LDH: 49.83% and 68.55%), and low-density lipoprotein cholesterol (70.63%; 59.18%) and improved redox status (MDA: 50.33%, 39.74%; and SH: 53.97%; 76.41%), respectively, when compared with the TD group. C. spicata plus RET promoted anti-hyperglycemic, lipid-reducing, and antioxidant effects in diabetic rats. Novelty C. spicata presents anti-hyperglycemic and lipid-lowering effects potentiated by RET. C. spicata reduces muscle injury and increases antioxidant defense.

Bone Marrow-Derived Mesenchymal Stem Cells Ameliorate the Pancreatic Changes of Chemically Induced Hypothyroidism by Carbimazole in Male Rats

We induced hypothyroidism (HT) in male rats through chronic oral administration of carbimazole and then tested whether an i.v. injection of rat bone marrow-derived mesenchymal stem cells (BM-MSCs) could ameliorate the HT-induced changes in pancreatic structure and function. The thyroid and pancreatic function tests, as well as total antioxidant capacity (TAC) and malondialdehyde (MDA) were estimated. The pancreatic structure was evaluated by hematoxylin and eosin (H&amp;E) stain. Insulin protein and cleaved caspase-3 were detected immunohistochemically. The degree of apoptosis was assessed by TUNEL assay. The morphometric measurements were done by an image analyzer system and the obtained data were statistically analyzed. HT rats showed hyperglycemia associated with insulin deficiency, decreased TAC and increased MDA levels. H&amp;E-stained sections showed that the pancreatic septa were infiltrated with acidophilic material. Some acini were vacuolated while others showed depleted acidophilia and dilated lumina. Spindle-shaped cells were accumulated within deformed islets in HT rats. The positive reaction with anti-cleaved caspase-3 was exclusively noted in the cytoplasm of islet cells with no immunostaining reaction in the acinar and ductal cells, whereas the positively stained nuclei with TUNEL were demonstrated in the islet and acinar cells. A significant increase in the apoptotic index % of both markers was detected. Injection of BM-MSCs in HT rats restored all biochemical indicators of disturbed pancreatic function to normal level and improved pancreatic structure, resulting in a clear septa and normal appearance of acini and islets. In conclusion, many of the significant structural and func tional pancreatic alterations detected in HT rats were ameliorated after the injection of BM-MSCs. These data demonstrate the ability of BM-MSCs to repair pancreatic disturbances. Further studies on humans are necessary to determine the potential clinical applications of BM-MSCs.

Peroxiredoxin6 in Endothelial Signaling

Peroxiredoxins (Prdx) are a ubiquitous family of highly conserved antioxidant enzymes with a cysteine residue that participate in the reduction of peroxides. This family comprises members Prdx1–6, of which Peroxiredoxin 6 (Prdx6) is unique in that it is multifunctional with the ability to neutralize peroxides (peroxidase activity) and to produce reactive oxygen species (ROS) via its phospholipase (PLA₂) activity that drives assembly of NADPH oxidase (NOX2). From the crystal structure, a C47 residue is responsible for peroxidase activity while a catalytic triad (S32, H26, and D140) has been identified as the active site for its PLA₂ activity. This paradox of being an antioxidant as well as an oxidant generator implies that Prdx6 is a regulator of cellular redox equilibrium (graphical abstract). It also indicates that a fine-tuned regulation of Prdx6 expression and activity is crucial to cellular homeostasis. This is specifically important in the endothelium, where ROS production and signaling are critical players in inflammation, injury, and repair, that collectively signal the onset of vascular diseases. Here we review the role of Prdx6 as a regulator of redox signaling, specifically in the endothelium and in mediating various pathologies.

Insulin resistance and diabetes in hyperthyroidism: a possible role for oxygen and nitrogen reactive species

In addition to insulin, glycemic control involves thyroid hormones. However, an excess of thyroid hormone can disturb the blood glucose equilibrium, leading to alterations of carbohydrate metabolism and, eventually, diabetes. Indeed, experimental and clinical hyperthyroidism is often accompanied by abnormal glucose tolerance. A common characteristic of hyperthyroidism and type 2 diabetes is the altered mitochondrial efficiency caused by the enhanced production of reactive oxygen and nitrogen species. It is known that an excess of thyroid hormone leads to increased oxidant production and mitochondrial oxidative damage. It can be hypothesised that these species represent the link between hyperthyroidism and development of insulin resistance and diabetes, even though direct evidence of this relationship is lacking. In this review, we examine the literature concerning the effects of insulin and thyroid hormones on glucose metabolism and discuss alterations of glucose metabolism in hyperthyroid conditions and the cellular and molecular mechanisms that may underline them.

The effect of prepregnancy body mass index on the risk of gestational diabetes mellitus: A systematic review and dose-response meta-analysis

This study was conducted to investigate the effect of the prepregnancy BMI on the risk of gestational diabetes mellitus (GDM). Five electronic databases, including PubMed, Scopus, Embase, Web of Science, and Google Scholar, were searched for literature published until 1 January 2018. The two-stage, random effect meta-analysis was performed to compare the dose-response relationship between BMI and GDM. As well as studies with categorized BMI, studies that treat BMI as a continuous variable were analysed. A total of 33 observational studies with an overall sample size of 962 966 women and 42 211 patients with GDM were included in analysis. The pooled estimate of GDM risk in the underweight, overweight, and obese pregnant women was 0.68, 2.01, and 3.98 using the adjusted OR and 0.34, 1.52, and 2.24 using the adjusted RR. The GDM risk increased 4% per unit of increase in BMI with both the crude and adjusted OR/RR models. Also, the risk of GDM increased 19% with the crude model and 14% with the adjusted model. The existence of dose-response relationship between the pre-pregnancy BMI and GDM can strengthen the scientific background for vigorous public health interventions for the control of pre-pregnancy BMI as well as the weight gain during pregnancy.

Treatment With Naringenin Elevates the Activity of Transcription Factor Nrf2 to Protect Pancreatic β-Cells From Streptozotocin-Induced Diabetes in vitro and in vivo

Chronic hyperglycemia and unusually high oxidative stress are the key contributors for diabetes in humans. Since nuclear factor E2-related factor 2 (Nrf2) controls the expression of antioxidant- and detoxification genes, it is hypothesized that targeted activation of Nrf2 using phytochemicals is likely to protect pancreatic β-cells, from oxidative damage, thereby mitigates the complications of diabetes. Naringenin is one such activator of Nrf2. However, it is currently not known whether the protective effect of naringenin against streptozotocin (STZ) induced damage is mediated by Nrf2 activation. Hence, the potential of naringenin to activate Nrf2 and protect pancreatic β-cells from STZ-induced damage in MIN6 cells is studied. In MIN6 cells, naringenin could activate Nrf2 and its target genes GST and NQO1, thereby inhibit cellular apoptosis. In animals, administration of 50 mg/kg body weight naringenin, for 45 days, significantly decreased STZ-induced blood glucose levels, normalized the lipid profile, and augmented the levels of antioxidants in pancreatic tissues. Immunohistochemical analysis measuring the number of insulin-positive cells in pancreas showed restoration of insulin expression similar to control animals. Furthermore, naringenin promoted glycolysis while inhibiting gluconeogenesis. In conclusion, naringenin could be a good anti-diabetic agent, which works by promoting Nrf2 levels and by decreasing cellular oxidative stress.

Signatures of selection and environmental adaptation across the goat genome post-domestication

BACKGROUND

Since goat was domesticated 10,000 years ago, many factors have contributed to the differentiation of goat breeds and these are classified mainly into two types: (i) adaptation to different breeding systems and/or purposes and (ii) adaptation to different environments. As a result, approximately 600 goat breeds have developed worldwide; they differ considerably from one another in terms of phenotypic characteristics and are adapted to a wide range of climatic conditions. In this work, we analyzed the AdaptMap goat dataset, which is composed of data from more than 3000 animals collected worldwide and genotyped with the CaprineSNP50 BeadChip. These animals were partitioned into groups based on geographical area, production uses, available records on solid coat color and environmental variables including the sampling geographical coordinates, to investigate the role of natural and/or artificial selection in shaping the genome of goat breeds.

RESULTS

Several signatures of selection on different chromosomal regions were detected across the different breeds, sub-geographical clusters, phenotypic and climatic groups. These regions contain genes that are involved in important biological processes, such as milk-, meat- or fiber-related production, coat color, glucose pathway, oxidative stress response, size, and circadian clock differences. Our results confirm previous findings in other species on adaptation to extreme environments and human purposes and provide new genes that could explain some of the differences between goat breeds according to their geographical distribution and adaptation to different environments.

CONCLUSIONS

These analyses of signatures of selection provide a comprehensive first picture of the global domestication process and adaptation of goat breeds and highlight possible genes that may have contributed to the differentiation of this species worldwide.

Comparative Biochemical and Histopathological Studies on the Efficacy of Metformin and Virgin Olive Oil against Streptozotocin-Induced Diabetes in Sprague-Dawley Rats

Treatment of diabetic patients with antioxidant, such as extra virgin olive oil (EVOO), may be beneficial in numerous debilitating complexities. This study was aimed at assessing the protective role of virgin olive oil in reducing hyperglycemia in streptozotocin- (STZ-) induced diabetic rats. Thirty-six healthy male Sprague-Dawley rats were divided into six groups (6 rats per group) including nondiabetic control (NC), diabetic control (DC), and animals treated with metformin, olive oil, and a combination of olive oil and metformin, respectively. The protective effect of olive oil was evaluated by determining the biochemical parameters (lipid profile, liver, and kidney) and by studying the histopathological alterations in pancreas, liver, and kidney tissues. The results showed a significant increase in alanine aminotransferase (ALT) and alkaline phosphatase (ALP) levels in diabetic rats. ALP levels remained significantly elevated in the diabetic rats that were treated with metformin and/or olive oil, and the highest level was noted in the group treated with olive oil (568.33 U/L). Contrarily, pretreatment with olive oil significantly decreased ALT (67.64 U/L) and ALP (226.17 U/L) levels. Histopathological data revealed that all the disorganized islets of Langerhans along with the clusters of inflammatory cells were absent in the group pretreated with the combination of virgin olive oil and metformin, which shows that prophylactic administration of this combination reduces the diabetic complications in a much better way. Therefore, pretreatment with olive oil with or without metformin is an encouraging approach for diabetes therapy with immense potential.

Protective Effect of Ipragliflozin on Pancreatic Islet Cells in Obese Type 2 Diabetic db/db Mice

Ipragliflozin is a selective sodium glucose cotransporter 2 (SGLT2) inhibitor that increases urinary glucose excretion and subsequently improves hyperglycemia in patients with type 2 diabetes mellitus (T2DM). To assess the beneficial effect of ipragliflozin on the mass and function of pancreatic β-cells under diabetic conditions, obese T2DM db/db mice were treated with ipragliflozin for 5 weeks. Glucose and lipid metabolism parameters, pathological changes in pancreatic islet cells and insulin content were evaluated. Pathological examination of pancreatic islet cells comprised measuring the ratios of insulin- and glucagon-positive cells and levels of oxidative stress markers. Hemoglobin A1c, plasma glucose, non-esterified fatty acid and triglyceride levels in ipragliflozin-treated groups were reduced compared to the diabetic control (DM-control) group. Histopathological examination of pancreatic islet cells revealed strong insulin staining and reduced glucagon staining in the ipragliflozin 10 mg/kg-treated group compared with the DM-control group. The ratio of α- to β-cell mass was lower in the ipragliflozin 10 mg/kg-treated group than the DM-control group and was similar to that of the non-diabetic control group. The density of immunostaining for 4-hydroxy-2-nonenal, an oxidative stress marker, in pancreatic islets was significantly lower in the ipragliflozin 10 mg/kg-treated group than the DM-control group. Pancreatic insulin content tended to be higher in the ipragliflozin-treated groups than the DM-control group. Our findings demonstrate the benefit of ipragliflozin treatment in improving glucolipotoxicity and reducing oxidative stress in pancreatic islet cells. Treatment with ipragliflozin may protect against the progressive loss of islet β-cells in patients with T2DM.

Hydroxysafflor yellow A attenuates high glucose-induced pancreatic β-cells oxidative damage via inhibiting JNK/c-jun signaling pathway

Pancreatic β-cells apoptosis and dysfunction induced by glucose toxicity were attributed to the formation of excess oxidative damage. Some studies have found that hydroxysafflor yellow A has strong effects to scavenge oxidative stress and inhibit apoptosis. In order to explore the influence of HSYA on oxidative stress induced by high glucose and the potential mechanisms, we set up a high glucose damage model and induced oxidative stress in INS-1 rat insulinoma cells. N-acetylcysteine was added as a group of oxidative stress scavenger. After 72 h of cultivation, the related indexes of oxidative stress (reactive oxygen species, catalase, glutathione peroxidase, lipid peroxidation, and superoxide dismutase), apoptosis (caspase3, parp) and the function of glucose stimulated insulin secretion were determined. In addition, the signaling pathway proteins of C-Jun NH2 -terminal kinases (JNK), phosphorylated JNK, C-jun, phosphorylated C-jun were evaluated. Fluorescence microscopy, qRT-PCR, western blotting were the main methods used in the experiment. Our results showed that hydroxysafflor yellow A reduced pancreatic β-cells apoptosis by attenuating oxidative damage, and JNK/c-Jun signaling pathway was involved. It indicated a significant mechanism for the positive impacts of HSYA on oxidative stress induced by high glucose, and provide important basis for using HSYA in diabetic prevention and therapy.

Redox regulation in regenerative medicine and tissue engineering: The paradox of oxygen

One of the biggest challenges in tissue engineering and regenerative medicine is to incorporate a functioning vasculature to overcome the consequences of a lack of oxygen and nutrients in the tissue construct. Otherwise, decreased oxygen tension leads to incomplete metabolism and the formation of the so‐called reactive oxygen species (ROS). Cells have many endogenous antioxidant systems to ensure a balance between ROS and antioxidants, but if this balance is disrupted by factors such as high levels of ROS due to long‐term hypoxia, there will be tissue damage and dysfunction. Current attempts to solve the oxygen problem in the field rarely take into account the importance of the redox balance and are instead centred on releasing or generating oxygen. The first problem with this approach is that although oxygen is necessary for life, it is paradoxically also a highly toxic molecule. Furthermore, although some oxygen‐generating biomaterials produce oxygen, they also generate hydrogen peroxide, a ROS, as an intermediate product. In this review, we discuss why it would be a superior strategy to supplement oxygen delivery with molecules to safeguard the important redox balance. Redox sensor proteins that can stimulate the anaerobic metabolism, angiogenesis, and enhancement of endogenous antioxidant systems are discussed as promising targets. We propose that redox regulating biomaterials have the potential to tackle some of the challenges related to angiogenesis and that the knowledge in this review will help scientists in tissue engineering and regenerative medicine realize this aim.

ATP sensitive K+ channel subunits (Kir6.1, Kir6.2) are the candidate mediators regulating ameliorating effects of pulsed magnetic field on aortic contractility in diabetic rats

Diabetes mellitus is a metabolic disease that causes increased morbidity and mortality in developed and developing countries. With recent advancements in technology, alternative treatment methods have begun to be investigated in the world. This study aims to evaluate the effect of pulsed magnetic field (PMF) on vascular complications and contractile activities of aortic rings along with Kir6.1 and Kir6.2 subunit expressions of ATP-sensitive potassium channels (K_ATP ) in aortas of controlled-diabetic and non-controlled diabetic rats. Controlled-diabetic and non-controlled diabetic adult male Wistar rats were exposed to PMF for a period of 6 weeks according to the PMF application protocol (1 h/day; intensity: 1.5 mT; consecutive frequency: 1, 10, 20, and 40 Hz). After PMF exposure, body weight and blood glucose levels were measured. Then, thoracic aorta tissue was extracted for relaxation-contraction and Kir6.1 and Kir6.2 expression experiments. Blood plasma glucose levels, body weight, and aortic ring contraction percentage decreased in controlled-diabetic rats but increased in non-controlled diabetic rats. PMF therapy repressed Kir6.1 mRNA expression in non-controlled diabetic rats but not in controlled diabetic rats. Conversely, Kir6.2 mRNA expressions were repressed both in controlled diabetic and non-controlled diabetic rats by PMF. Our findings suggest that the positive therapeutic effects of PMF may act through (K_ATP ) subunits and may frequently occur in insulin-free conditions. Bioelectromagnetics. 39:299-311, 2018. © 2018 Wiley Periodicals, Inc.

Caralluma fimbriata and metformin protection of rat pancreas from high fat diet induced oxidative stress

A high fat diet promotes oxidative stress, which contributes to the development of pancreatic fibrosis. We compared the protective effects of a hydroalcoholic extract of Caralluma fimbriata (CFE) to metformin (Met) in the pancreas of Wistar rats fed a high fat diet. The experimental animals were divided into five groups: control (C), treated with CFE (C + CFE), treated with high fat diet (HFD), high fat diet treated with CFE (HFD + CFE), and high fat diet treated with metformin (Met) (HFD + Met). CFE was administered orally to groups C + CFE and HFD + CFE rats for 90 days. Met was given to the HFD + Met group. After 90 days, oxidative stress markers in the pancreas including reduced glutathione (GSH), lipid oxidation (LO), protein oxidation (PO), and activities of antioxidant and polyol pathway enzymes, aldose reductase (AR) and sorbitol dehydrogenase (SDH) were assayed and tissue histology was examined. Establishment of oxidative stress in high fat diet fed rats was verified by elevated LO and PO, decreased GSH, decreased activities of antioxidants and increased activities of polyol pathway enzymes. Oxidative stress was prevented in HFD + CFE and HFD + Met groups. Group C + CFE exhibited improved antioxidant status compared to group C. CFE treatment prevented high fat diet induced acinar cell degeneration, necrosis, edema and hemorrhage. CFE could be used as adjuvant therapy for preventing or managing high fat diet induced pancreatic damage.

Relationship between fat mass and obesity-associated gene expression and type 2 diabetes mellitus severity

This study sought to investigate any correlation between fat mass and obesity-associated gene (FTO) expression and the severity of type 2 diabetes mellitus (T2DM). In total 110 patients newly diagnosed with T2DM in the outpatient department of Yantai Yuhuangding Hospital between September 2016 and March 2017 were selected as study subjects and were divided into severe (58 cases) and mild groups (52 cases) according to T2DM severity. Patients in the severe group were followed up for 12 weeks. An additional 60 healthy individuals were selected to serve as the normal control group. Fasting plasma glucose (FPG), fasting insulin (FINs), fasting C-peptide (FCP), glycosylated hemoglobin (HbA1c) and homeostasis model assessment of insulin resistance (HOMA-IR) were examined for every patient in the study. Real-time polymerase chain reaction (RT-PCR) was used to detect FTO messenger ribonucleic acid (mRNA) expression levels in patient peripheral blood lymphocytes. Western blotting was used to detect serum FTO protein expression levels, upon which the correlation between FTO protein levels and all other indices were analyzed. Compared with the normal control group, both T2DM groups showed significantly increased waist circumferences, hip circumferences, body mass indexes (BMIs), blood glucose indexes (FPG, FCP, HbA1c, FINs, HOMA-IR) and FTO mRNA/protein levels (p<0.05). Additionally, the increases presented by the severe T2DM group were significantly greater than those presented by the mild T2DM group (p<0.05). After 12 weeks of treatment, the severe T2DM group showed decreased BMI, blood glucose index and FTO protein expression (p<0.05). FTO protein expression in T2DM patients was higher than in healthy controls, with severe patients showing greater expression levels than mild group patients. FTO expression was positively correlated with BMI, waist circumference, chest circumference, FPG, FCP, HbA1c, FINs and HOMA-IR. Therefore, FTO expression can serve as a marker for the clinical diagnosis and treatment of T2DM.

Interaction between a variant of chromosome 9p21.3 locus and diet antioxidant capacity on metabolic syndrome in Tehrani adults

BACKGROUND

Genome-wide association studies have shown that risk alleles on chromosome 9p21.3 locus, are associated with increasing the risk of cardiovascular diseases (CVDs). Several epidemiological studies have found that metabolic syndrome (MetS) is associated with CVDs. Dietary antioxidants also have shown to have potential favorable effects on MetS prevention. This study examined the interactions between rs1333048 genotypes on 9p21 genetic region and Total antioxidant capacity (TAC) on odds of MetS.

METHODS

263 Tehrani adults were enrolled in this cross-sectional study. The MetS was defined according to the ATPIII. Dietary intake was assessed daily using a FFQ with 147 items. Dietary TAC was assessed according to United States Department of Agriculture database for oxygen radical absorbance capacity (ORAC). Bioelectrical impedance analysis method was used for body analysis and rs1333048 were genotyped by restriction fragment length polymorphism method. Participants were categorized into three groups based on rs1333048 genotypes.

RESULTS

The results demonstrate that, prevalence of C allele was 52.85% and A allele was 47.15%. After adjustment for confunder variable, this study demonstrated an interaction between AA genotype and high Lyophilic oxygen radical absorbance capacity (L-ORAC) and high Hydrophilic oxygen radical absorbance capacity (H-ORAC) intake on low odds of MetS (OR = 0.24, 95% CI = 0.06-0.94, P for interaction = 0.04, OR = 0.26, 95% CI = 0.06-0.99, P for interaction = 0.04). Also, our result indicated, there was no interaction between AA genotype and high total oxygen radical absorbance capacity (T-ORAC) and total phenolic intakes on reduce odds of MetS (OR = 0.07, 95% CI = 0.07-1.10, P for interaction = 0.07, OR = 0.58, 95% CI = 0.16-2.07, P for interaction = 0.40) respectively.

CONCLUSION

The results of the present study indicate that high L-ORAC and high H-ORAC intake may modify the elevated odds of MetS in AA genotype of rs1333048 on the 9p21 genetic locus.

Solid Lipid Nanoparticles of Myricitrin Have Antioxidant and Antidiabetic Effects on Streptozotocin-Nicotinamide-Induced Diabetic Model and Myotube Cell of Male Mouse

Type 2 diabetes mellitus (T2DM) may occur via oxidative stress. Myricitrin is a plant-derived antioxidant, and its solid lipid nanoparticle (SLN) may be more potent. Hence, the present study was conducted to evaluate the effects of myricitrin SLN on streptozotocin-nicotinamide- (STZ-NA-) induced T2DM of the mouse and hyperglycemic myotube. In this experimental study, cold homogenization method was used to prepare SLN. Then, 120 adult male NMRI mice were divided into 7 groups: control, vehicle, diabetes (received STZ 65 mg/kg 15 min after injected NA 120 mg/kg), diabetes + SLN containing myricitrin 1, 3, and 10 mg/kg, and diabetes + metformin. For in vitro study, myoblast (C2C12) cell line was cultured and divided into 6 groups (n = 3): control, hyperglycemia, hyperglycemia + SLN containing myricitrin 1, 3, and, 10 μM, and hyperglycemia + metformin. After the last nanoparticle treatment, plasma samples, pancreas and muscle tissues, and myotubes were taken for experimental assessments. Diabetes increased lipid peroxidation and reduced antioxidant defense along with the hyperglycemia, insulin resistance, and pancreas apoptosis. Hyperglycemia induced oxidative stress, antioxidant impairment, and cellular apoptosis. Myricitrin SLN improved diabetes and hyperglycemia complications in the in vivo and in vitro studies. Therefore, SLN of myricitrin showed antioxidant, antidiabetic, and antiapoptotic effects in the mouse and myotube cells.