Proposed mechanisms for the induction of insulin resistance by oxidative stress

A review of antioxidant N-acetylcysteine in addressing polycystic ovary syndrome

N-acetylcysteine (NAC), a compound known for its cysteine and glutathione precursor properties, has been used in therapeutic applications for many years. Recently, there has been increasing interest in exploring the potential benefits of NAC in addressing polycystic ovary syndrome (PCOS). However, the exact mechanisms underlying NAC's therapeutic and clinical uses remain not fully understood. This review aims to specifically investigate how NAC offers protection against PCOS. This involved an extensive systematic review of the literature, and it made use of PubMed, Embase, and Web of Science databases. By analyzing key findings from over 100 research papers, the potential mechanisms through which NAC produces its effects were explored and summarized. Most studies suggest that NAC, whether used on its own or in combination with other medications, has the potential to counteract oxidative stress, utilize its anti-inflammatory and anti-apoptotic properties, and offer benefits in managing PCOS. Moreover, NAC might have the potential to influence specific signaling pathways in insulin target cells and β cells. Diverse biological effects of NAC indicate its potential usefulness as a supplementary or therapeutic approach for managing PCOS. As a result, additional research is required to explore its potential in addressing PCOS.

Development of a microfluidic wearable electrochemical sensor for the non-invasive monitoring of oxidative stress biomarkers in human sweat

Oxidative stress is widely recognized as a pivotal factor contributing to numerous Central Nervous System (CNS) ailments. The concentrations of hydrogen peroxide (H2O2) and phosphorylated proteins within the human body serve as crucial indicators of oxidative stress. As such, the real-time monitoring of H2O2 and phosphorylated proteins in sweat is vital for the early identification, diagnosis, and management of diseases linked to oxidative stress. In this context, we present a novel microfluidic wearable electrochemical sensor by modifying the electrode with Prussian blue (PB) and loading sulfur-rich vacancy-containing molybdenum disulfide (MoS2-X) onto Multi-walled carbon nanotube (CNTs) to form coaxially layered CNTs/MoS2-X, which was then synthesized with highly dispersed titanium dioxide nanoparticles (TiO2) to synthesize CNTs/MoS2-X/TiO2 composites for the detection of human sweat H2O2 and phosphorylated proteins, respectively. This structure, with its sulfur vacancies and coaxial layering, significantly improved sensitivity of electrochemical sensors, allowing it to detect H2O2 in a range of 0.01-1 mM with a detection limit of 4.80 μM, and phosphoproteins in a range of 0.01-1 mg/mL with a threshold of 0.917 μg/mL. Furthermore, the miniature sensor demonstrates outstanding performance in detecting analytes in both simulated and real sweat. Comprehensive biosafety assessments have validated the compatibility of the electrode material, underscoring the potential of sensor as a reliable and non-invasive method for tracking biomarkers linked to CNS disorders. This microfluidic wearable electrochemical biosensor with high performance and biosafety features shows great promise for the development of cutting-edge wearable technology devices for tracking CNS disease indicators.

Eupatilin mitigates Gestational diabetes in streptozotocin-induced diabetic pregnant rats through the Regulation of inflammation and oxidative stress

Gestational diabetes mellitus (GDM) is a common metabolic disease that is typically diagnosed in pregnant women. The current study was aimed at disclosing the salutary activities of eupatilin against streptozotocin (STZ)-induced GDM in rats. The pregnant rats were induced with GDM and then treated with eupatilin for 20 days. The bodyweight, pup numbers and survival, glucose, and insulin levels were estimated. The levels of biochemical markers, antioxidants, and lipid profiles were measured using kits. The histopathological analysis was done on the pancreas and liver tissues. The eupatilin effectively reduced glucose and boosted insulin levels in the GDM rats. The pup numbers and their survival index were increased by the eupatilin treatment. The lipase, creatinine, AST, ALT, and urea levels were effectively reduced by the eupatilin in the GDM rats. Eupatilin treatment also decreased oxidative stress by increasing antioxidant levels and reducing inflammatory cytokine levels in the GDM rats. The cholesterol, LDL, and triglyceride levels were effectively decreased, and HDL was elevated by eupatilin. The results of histopathological analysis of both liver and pancreatic tissues also demonstrated the therapeutic properties of eupatilin. In conclusion, the current results prove that eupatilin can be an effective salutary candidate to treat GDM.

Pterostilbene alleviates cafeteria diet-induced obesity and underlying depression in adolescent male Swiss albino mice and affects insulin resistance, inflammation, HPA axis dysfunction and SIRT1 mediated leptin-ghrelin signaling

Cafeteria diet (CD) model for in-vivo studies mimics the western diet having imbalanced nutritional value, high caloric-density and palatability. Uncontrolled eating leads to the development of childhood obesity, poor self-esteem and depression due to its effects on brain development. Herbal supplements are novel inclusion in the management of obesity and mental well-being. Pterostilbene (PTE) found in blueberries and Pterocarpus marsupium heartwood, is known to prevent obesity in invivo models. Adolescent Swiss albino male mice were fed on CD for 70 days and the development of obesity was assessed by gain in body weight, abdominal circumference. Forced swim and tail suspension test confirmed depression in CD fed mice. Obesity induced depressed (OID) mice were treated with PTE (10, 20, 40 mg/kg), standard antiobesity drug cetilistat (10 mg/kg), antidepressant fluoxetine (10 mg/kg) for 28 days. Post treatment, PTE-treated mice showed reduction in BW and depression-like behavior analysed using paradigms such as sucrose preference, open field, marble burying, and resident intruder test in comparison to the CD group. Insulin resistance, lipid profile, antioxidant enzyme, inflammatory cytokines (NF-κB, IL-6, TNF α) and cortisol levels were mitigated by PTE. It also restored normal cellular architecture of the brain and adipose tissue and increased the Silent mating type information regulation 2 homolog1 (SIRT1), leptin and ghrelin receptors gene expression in the brain. Thus, it can be concluded that PTE might have inhibited OID like behavior in mice via inhibition of IR, modulating neuroinflammation and hypothalamic-pituitary-adrenal axis dysfunction and upregulating SIRT1 mediated leptin-ghrelin signaling.

Types of memory, dementia, Alzheimer's disease, and their various pathological cascades as targets for potential pharmacological drugs

Alzheimer's disease (AD) is the most common type of dementia accounting for 90% of cases; however, frontotemporal dementia, vascular dementia, etc. prevails only in a minority of populations. The term dementia is defined as loss of memory which further takes several other categories of memories like working memory, spatial memory, fear memory, and long-term, and short-term memory into consideration. In this review, these memories have critically been elaborated based on context, duration, events, appearance, intensity, etc. The most important part and purpose of the review is the various pathological cascades as well as molecular levels of targets of AD, which have extracellular amyloid plaques and intracellular hyperphosphorylated tau protein as major disease hallmarks. There is another phenomenon that either leads to or arises from the above-mentioned hallmarks, such as oxidative stress, mitochondrial dysfunction, neuroinflammation, cholinergic dysfunction, and insulin resistance. Several potential drugs like antioxidants, anti-inflammatory drugs, acetylcholinesterase inhibitors, insulin mimetics or sensitizers, etc. studied in various previous preclinical or clinical reports were put as having the capacity to act on these pathological targets. Additionally, agents directly or indirectly targeting amyloid and tau were also discussed. This could be further investigated in future research.

Antagonizing Effects of Chromium Against Iron-Decreased Glucose Uptake by Regulating ROS-Mediated PI3K/Akt/GLUT4 Signaling Pathway in C2C12

To investigate the effect of chromium and iron on glucose metabolism via the PI3K/Akt/GLUT4 signaling pathway. Skeletal muscle gene microarray data in T2DM (GSE7014) was selected using Gene Expression Omnibus database. Element-gene interaction datasets of chromium and iron were extracted from comparative toxicogenomics database (CTD). Gene ontology (GO)and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed using DAVID online tool. Cell viability, insulin-stimulated glucose uptake, intracellular reactive oxygen species (ROS) level, and protein expression level were measured in C2C12 cells. The bioinformatics research indicated that PI3K/Akt signaling pathway participated in the effects of chromium and iron associated with T2DM. Insulin-stimulated glucose uptake level was significantly higher in chromium picolinate (Cr group) and lower in ammonium iron citrate (FA group) than that for the control group (P < 0.05); chromium picolinate + ammonium iron citrate (Cr + FA group) glucose uptake level was higher than that for the FA group (P < 0.05). Intracellular ROS level was significantly higher in the FAC group than that for the control group (P < 0.05), and that for the Cr + FA group was lower than that for the FA group (P < 0.05). p-PI3K/PI3K, p-Akt/Akt, and GLUT4 levels were significantly lower in the FA group than that for the control group (P < 0.05), and the Cr + FA group had higher levels than the FA group (P < 0.05). Chromium might have a protective effect on iron-induced glucose metabolism abnormalities through the ROS-mediated PI3K/Akt/GLUT4 signaling pathway.

Antioxidant peptides, the guardian of life from oxidative stress

Reactive oxygen species (ROS) are produced during oxidative metabolism in aerobic organisms. Under normal conditions, ROS production and elimination are in a relatively balanced state. However, under internal or external environmental stress, such as high glucose levels or UV radiation, ROS production can increase significantly, leading to oxidative stress. Excess ROS production not only damages biomolecules but is also closely associated with the pathogenesis of many diseases, such as skin photoaging, diabetes, and cancer. Antioxidant peptides (AOPs) are naturally occurring or artificially designed peptides that can reduce the levels of ROS and other pro-oxidants, thus showing great potential in the treatment of oxidative stress-related diseases. In this review, we discussed ROS production and its role in inducing oxidative stress-related diseases in humans. Additionally, we discussed the sources, mechanism of action, and evaluation methods of AOPs and provided directions for future studies on AOPs.

Metabolic Syndrome: A Narrative Review from the Oxidative Stress to the Management of Related Diseases

Metabolic syndrome (MS) is a growing disorder affecting thousands of people worldwide, especially in industrialised countries, increasing mortality. Oxidative stress, hyperglycaemia, insulin resistance, inflammation, dysbiosis, abdominal obesity, atherogenic dyslipidaemia and hypertension are important factors linked to MS clusters of different pathologies, such as diabesity, cardiovascular diseases and neurological disorders. All biochemical changes observed in MS, such as dysregulation in the glucose and lipid metabolism, immune response, endothelial cell function and intestinal microbiota, promote pathological bridges between metabolic syndrome, diabesity and cardiovascular and neurodegenerative disorders. This review aims to summarise metabolic syndrome's involvement in diabesity and highlight the link between MS and cardiovascular and neurological diseases. A better understanding of MS could promote a novel strategic approach to reduce MS comorbidities.

Antioxidant enzymes and Nrf2/Keap1 in human skeletal muscle: Influence of age, sex, adiposity and aerobic fitness

Ageing, a sedentary lifestyle, and obesity are associated with increased oxidative stress, while regular exercise is associated with an increased antioxidant capacity in trained skeletal muscles. Whether a higher aerobic fitness is associated with increased expression of antioxidant enzymes and their regulatory factors in skeletal muscle remains unknown. Although oestrogens could promote a higher antioxidant capacity in females, it remains unknown whether a sex dimorphism exists in humans regarding the antioxidant capacity of skeletal muscle. Thus, the aim was to determine the protein expression levels of the antioxidant enzymes SOD1, SOD2, catalase and glutathione reductase (GR) and their regulatory factors Nrf2 and Keap1 in 189 volunteers (120 males and 69 females) to establish whether sex differences exist and how age, VO2max and adiposity influence these. For this purpose, vastus lateralis muscle biopsies were obtained in all participants under resting and unstressed conditions. No significant sex differences in Nrf2, Keap1, SOD1, SOD2, catalase and GR protein expression levels were observed after accounting for VO2max, age and adiposity differences. Multiple regression analysis indicates that the VO2max in mL.kg LLM-1.min-1can be predicted from the levels of SOD2, Total Nrf2 and Keap1 (R = 0.58, P < 0.001), with SOD2 being the main predictor explaining 28 % of variance in VO2max, while Nrf2 and Keap1 explained each around 3 % of the variance. SOD1 protein expression increased with ageing in the whole group after accounting for differences in VO2max and body fat percentage. Overweight and obesity were associated with increased pSer40-Nrf2, pSer40-Nrf2/Total Nrf2 ratio and SOD1 protein expression levels after accounting for differences in age and VO2max. Overall, at the population level, higher aerobic fitness is associated with increased basal expression of muscle antioxidant enzymes, which may explain some of the benefits of regular exercise.

Research Progress on the Relationship between Vitamins and Diabetes: Systematic Review

Diabetes is a serious chronic metabolic disease that causes complications over time, bringing serious public health challenges that affect different countries across the world. The current clinical drugs for diabetes may lead to adverse effects such as hypoglycemia and liver and abdominal distension and pain, which prompt people to explore new treatments for diabetes without side effects. The research objective of this review article is to systematically review studies on vitamins and diabetes and to explain their possible mechanism of action, as well as to assess the role of vitamins as drugs for the prevention and treatment of diabetes. To achieve our objective, we searched scientific databases in PubMed Central, Medline databases and Web of Science for articles, using "vitamin" and "diabetes" as key words. The results of numerous scientific investigations revealed that vitamin levels were decreased in humans and animals with diabetes, and vitamins show promise for the prevention and/or control of diabetes through anti-inflammation, antioxidation and the regulation of lipid metabolism. However, a few studies showed that vitamins had no positive effect on the development of diabetes. Currently, studies on vitamins in the treatment of diabetes are still very limited, and there are no clinical data to clarify the dose-effect relationship between vitamins and diabetes; therefore, vitamins are not recommended as routine drugs for the treatment of diabetes. However, we still emphasize the great potential of vitamins in the prevention and treatment of diabetes, and higher quality studies are needed in the future to reveal the role of vitamins in the development of diabetes.

N-acetylcysteine alleviates oxidative stress and apoptosis and prevents skeletal muscle atrophy in type 1 diabetes mellitus through the NRF2/HO-1 pathway

AIMS

Type 1 diabetes mellitus (T1DM) has been linked to the occurrence of skeletal muscle atrophy. Insulin monotherapy may lead to excessive blood glucose fluctuations. N-acetylcysteine (NAC), a clinically employed antioxidant, possesses cytoprotective, anti-inflammatory, and antioxidant properties. The objective of our study was to evaluate the viability of NAC as a supplementary treatment for T1DM, specifically regarding its therapeutic and preventative impacts on skeletal muscle.

MAIN METHODS

Here, we used beagles as T1DM model for 120d to explore the mechanism of NRF2/HO-1-mediated skeletal muscle oxidative stress and apoptosis and the therapeutic effects of NAC. Oxidative stress and apoptosis related factors were analyzed by immunohistochemistry, immunofluorescence, western blotting, and RT-qPCR assay.

KEY FINDINGS

The findings indicated that the co-administration of NAC and insulin led to a reduction in creatine kinase levels, preventing weight loss and skeletal muscle atrophy. Improvement in the reduction of muscle fiber cross-sectional area. The expression of Atrogin-1, MuRF-1 and MyoD1 was downregulated, while Myh2 and MyoG were upregulated. In addition, CAT and GSH-Px levels were increased, MDA levels were decreased, and redox was maintained at a steady state. The decreased of key factors in the NRF2/HO-1 pathway, including NRF2, HO-1, NQO1, and SOD1, while KEAP1 increased. In addition, the apoptosis key factors Caspase-3, Bax, and Bak1 were found to be downregulated, while Bcl-2, Bcl-2/Bax, and CytC were upregulated.

SIGNIFICANCE

Our findings demonstrated that NAC and insulin mitigate oxidative stress and apoptosis in T1DM skeletal muscle and prevent skeletal muscle atrophy by activating the NRF2/HO-1 pathway.

Oxidant-modified amylin fibrils and aggregates alter the inflammatory profile of multiple myeloid cell types, but are non-toxic to islet β cells

Diabetes mellitus currently affects ∼10% of the population worldwide, with Type 2 predominating, and this incidence is increasing steadily. Both Type 1 and 2 are complex diseases, involving β-cell death and chronic inflammation, but the pathways involved are unresolved. Chronic inflammation is characterized by increased oxidant formation, with this inducing protein modification, altered function and immunogenicity. Amylin, a peptide hormone co-secreted with insulin by β-cells, has attracted considerable interest for its amyloidogenic properties, however, the effects that oxidants have on amylin aggregation and function are poorly understood. Amylin was exposed in vitro to hypochlorous acid, hydrogen peroxide and peroxynitrous acid/peroxynitrite to investigate the formation of post-translational oxidative modifications (oxPTMs, via mass spectrometry) and fibril formation (via transmission electron microscopy). Amylin free acid (AFA) was also examined to investigate the role of the C-terminal amide in amylin. Oxidant exposure led to changes in aggregate morphology and abundance of oxPTMs in a concentration-dependent manner. The toxicity and immunogenic potential of oxidant-modified amylin or AFA on pancreatic islet cells (INS-1E), human monocyte cell line (THP-1) and monocyte-derived dendritic cells (moDCs) were examined using metabolic activity and cytokine assays, and flow cytometry. No significant changes in vitality or viability were detected, but exposure to oxidant-modified amylin or AFA resulted in altered immunogenicity when compared to the native proteins. THP-1 and moDCs show altered expression of activation markers and changes in cytokine secretion. Furthermore, oxidant-treated amylin and AFA promoted maturation of THP-1 and pre-mature moDCs, as determined by changes in size, and maturation markers.

Oxidative Stress Linking Obesity and Cancer: Is Obesity a 'Radical Trigger' to Cancer?

Obesity is on the rise worldwide, and consequently, obesity-related non-communicable diseases are as well. Nutritional overload induces metabolic adaptations in an attempt to restore the disturbed balance, and the byproducts of the mechanisms at hand include an increased generation of reactive species. Obesity-related oxidative stress causes damage to vulnerable systems and ultimately contributes to neoplastic transformation. Dysfunctional obese adipose tissue releases cytokines and induces changes in the cell microenvironment, promoting cell survival and progression of the transformed cancer cells. Other than the increased risk of cancer development, obese cancer patients experience higher mortality rates and reduced therapy efficiency as well. The fact that obesity is considered the second leading preventable cause of cancer prioritizes the research on the mechanisms connecting obesity to cancerogenesis and finding the solutions to break the link. Oxidative stress is integral at different stages of cancer development and advancement in obese patients. Hypocaloric, balanced nutrition, and structured physical activity are some tools for relieving this burden. However, the sensitivity of simultaneously treating cancer and obesity poses a challenge. Further research on the obesity-cancer liaison would offer new perspectives on prevention programs and treatment development.

Production of Food-Derived Bioactive Peptides with Potential Application in the Management of Diabetes and Obesity: A Review

The prevalence of diabetes mellitus and obesity is increasing worldwide. Bioactive peptides are naturally present in foods or in food-derived proteins. Recent research has shown that these bioactive peptides have an array of possible health benefits in the management of diabetes and obesity. First, this review will summarize the top-down and bottom-up production methods of the bioactive peptides from different protein sources. Second, the digestibility, bioavailability, and metabolic fate of the bioactive peptides are discussed. Last, the present review will discuss and explore the mechanisms by which these bioactive peptides help against obesity and diabetes based on in vitro and in vivo studies. Although several clinical studies have demonstrated that bioactive peptides are beneficial in alleviating diabetes and obesity, more double-blind randomized controlled trials are needed in the future. This review has provided novel insights into the potential of food-derived bioactive peptides as functional foods or nutraceuticals to manage obesity and diabetes.

Short-term administration of tibolone reduces inflammation and oxidative stress in the hippocampus of ovariectomized rats fed high-fat and high-fructose

Inflammation and oxidative stress are critical events involved in neurodegeneration. In animal models, it has been shown that chronic consumption of a hypercaloric diet, which leads to inflammatory processes, affects the hippocampus, a brain region fundamental for learning and memory processes. In addition, advanced age and menopause are risk factors for neurodegeneration. Hormone replacement therapy (HRT) ameliorates menopause symptoms. Tibolone (TB), a synthetic hormone, exerts estrogenic, progestogenic and androgenic effects on different tissues. We aimed to determine the effect of short-term TB administration on oxidative stress and inflammation markers in the hippocampus of ovariectomized rats fed a high-fat-and-fructose diet (HFFD). Adult female rats were ovariectomized (OVX) and fed standard diet or HFFD-consisting of 10% lard supplemented chow and 20% high-fructose syrup in the drinking water-and administered vehicle or TB (1 mg/kg for seven days). Finally, we administered hormone receptor antagonists (MPP, RU486 or FLU) to each of the OVX + HFFD + TB groups. Bodyweight, triglycerides and cholesterol, oxidative stress and inflammation markers, and the activity and expression of antioxidant enzymes were quantified in the hippocampus of each experimental group. We observed that short-term TB administration significantly reduced body weight, AGEs, MDA levels, increased SOD and GPx activity, improved GSH/GSSG ratio, and reduced IL-6 and TNF-α. Our findings suggest that short-term administration of TB decreases oxidative stress and reduces inflammation caused by HFFD and early estrogenic decline. These effects occurred via estrogen receptor alpha.

Tactics with Prebiotics for the Treatment of Metabolic Dysfunction-Associated Fatty Liver Disease via the Improvement of Mitophagy

Mitophagy/autophagy plays a protective role in various forms of liver damage, by renovating cellular metabolism linking to sustain liver homeostasis. A characterized pathway for mitophagy is the phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1)/Parkin-dependent signaling pathway. In particular, PINK1-mediated mitophagy could play an indispensable role in improving the metabolic dysfunction-associated fatty liver disease (MAFLD) which could precede to steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma. In addition, the PI3K/AKT/mTOR pathway might regulate the various characteristics of cellular homeostasis including energy metabolism, cell proliferation, and/or cell protection. Therefore, targeting mitophagy with the alteration of PI3K/AKT/mTOR or PINK1/Parkin-dependent signaling to eliminate impaired mitochondria might be an attractive strategy for the treatment of MAFLD. In particular, the efficacy of prebiotics for the treatment of MAFLD has been suggested to be useful via the modulation of the PI3K/AKT/mTOR/AMPK pathway. Additionally, several edible phytochemicals could activate mitophagy for the improvement of mitochondrial damages, which could also be a promising option to treat MAFLD with providing liver protection. Here, the potential therapeutics with several phytochemicals has been discussed for the treatment of MAFLD. Tactics with a viewpoint of prospective probiotics might contribute to the development of therapeutic interventions.

Biomarkers of oxidative stress and reproductive complications

Oxidative stress is the result of an imbalance between the formation of reactive oxygen species (ROS) and the levels of enzymatic and non-enzymatic antioxidants. The assessment of biological redox status is performed by the use of oxidative stress biomarkers. An oxidative stress biomarker is defined as any physical structure or process or chemical compound that can be assessed in a living being (in vivo) or in solid or fluid parts thereof (in vitro), the determination of which is a reproducible and reliable indicator of oxidative stress. The use of oxidative stress biomarkers allows early identification of the risk of developing diseases associated with this process and also opens up possibilities for new treatments. At the end of the last century, interest in oxidative stress biomarkers began to grow, due to evidence of the association between the generation of free radicals and various pathologies. Up to now, a significant number of studies have been carried out to identify and apply different oxidative stress biomarkers in clinical practice. Among the most important oxidative stress biomarkers, it can be mentioned the products of oxidative modifications of lipids, proteins, nucleic acids, and uric acid as well as the measurement of the total antioxidant capacity of fluids in the human body. In this review, we aim to present recent advances and current knowledge on the main biomarkers of oxidative stress, including the discovery of new biomarkers, with emphasis on the various reproductive complications associated with variations in oxidative stress levels.

Transgenic type2 diabetes mouse models for in vivo redox measurement of hepatic mitochondrial oxidative stress

BACKGROUND

Oxidative stress is involved in the progression of diabetes and its associated complications. However, it is unclear whether increased oxidative stress plays a primary role in the onset of diabetes or is a secondary indicator caused by tissue damage. Previous methods of analyzing oxidative stress have involved measuring the changes in oxidative stress biomarkers. Our aim is to identify a novel approach to clarify whether oxidative stress plays a primary role in the onset of diabetes.

METHODS

We constructed transgenic type 2 diabetes mouse models expressing redox-sensitive green fluorescent proteins (roGFPs) that distinguished between mitochondria and whole cells. Pancreas, liver, skeletal muscle, and kidney redox states were measured in vivo.

RESULTS

Hepatic mitochondrial oxidation increased when the mice were 4 weeks old and continued to increase in an age-dependent manner. The increase in hepatic mitochondrial oxidation occurred simultaneously with weight gain and increased blood insulin levels before the blood glucose levels increased. Administering the oxidative stress inducer acetaminophen increased the vulnerability of the liver mitochondria to oxidative stress.

CONCLUSIONS

This study demonstrates that oxidative stress in liver mitochondria in mice begins at the onset of diabetes rather than after the disease has progressed.

GENERAL SIGNIFICANCE

RoGFP-expressing transgenic type 2 diabetes mouse models are effective and convenient tools for measuring hepatic mitochondrial redox statuses in vivo. These models may be used to assess mitochondria-targeting antioxidants and establish the role of oxidative stress in type 2 diabetes.

Docosahexaenoic acid enhances hippocampal insulin sensitivity to promote cognitive function of aged rats on a high-fat diet

INTRODUCTION

Diminished brain insulin sensitivity is associated with reduced cognitive function. Docosahexaenoic acid (DHA) is known to maintain normal brain function.

OBJECTIVES

This study aimed to determine whether DHA impacts hippocampal insulin sensitivity and cognitive function in aged rats fed a high-fat diet (HFD).

METHODS

Eight-month-old female Sprague-Dawley rats were randomly divided into three groups (n = 50 each). Rats in the aged group, HFD group, and DHA treatment group received standard diet (10 kcal% fat), HFD (45 kcal% fat), and DHA-enriched HFD (45 kcal% fat, 1% DHA, W/W) for 10 months, respectively. Four-month-old female rats (n = 40) that received a standard diet served as young controls. Neuroinflammation, oxidative stress, amyloid formation, and tau phosphorylation in the hippocampus, as well as systemic glucose homeostasis and cognitive function, were tested.

RESULTS

DHA treatment relieved a block in the insulin signaling pathway and consequently protected aged rats against HFD-induced hippocampal insulin resistance. The beneficial effects were explained by a DHA-induced decrease in systemic glucose homeostasis dysregulation, hippocampal neuroinflammation and oxidative stress. In addition, DHA treatment broke the reciprocal cycle of hippocampal insulin resistance, Aβ burden, and tau hyperphosphorylation. Importantly, treatment of model rats with DHA significantly increased their cognitive capacity, as evidenced by their increased hippocampal-dependent learning and memory, restored neuron morphology, enhanced cholinergic activity, and activated cyclic AMP-response element-binding protein.

CONCLUSION

DHA improves cognitive function by enhancing hippocampal insulin sensitivity.

The chemical profiling and assessment of antioxidative, antidiabetic and antineurodegenerative potential of Kombucha fermented Camellia sinensis, Coffea arabica and Ganoderma lucidum extracts

The scientific interest in the medicinal properties of Kombucha beverages, a carbonated drink with live microorganisms, has increased recently. Hence, the aim of this study was to determine the chemical profile and to examine the antioxidant, antidiabetic and antineurodegenerative potential of unfermented and also Kombucha fermented Camellia sinensis (green tea), Coffea arabica (coffee), and Ganoderma lucidum (Reishi) extracts. The extracts were prepared as follows: the first (unfermented) set contained 1 L of water, 50 g of sucrose and 20 g of dried and ground green tea, coffee, or Reishi basidiocarp, while the second (fermented) set contained all of the aforementioned ingredients individually inoculated with Kombucha and fermented for 21 days. The chemical analysis was conducted using liquid chromatography-mass spectrometry (LC-MS). The antioxidant activity was assessed by DPPH, total reducing power (TRP), and β-carotene bleaching assays. The inhibition of α-amylase and α-glucosidase activity was used to estimate the antidiabetic potential, while the level of inhibition of acetylcholinesterase (AChE) and tyrosinase (TYR) was used to evaluate the antineurodegenerative activity. The results suggested that the fermented extracts of green tea, coffee, and Reishi exert significant antioxidant effects, although they were lower compared to the unfermented extracts. The unfermented green tea extract exhibited the highest DPPH-scavenging activity (87.46%) and the highest preservation of β-carotene (92.41%), while the fermented coffee extract showed the highest TRP (120.14 mg AAE per g) at 10 mg mL^-1. Although the extracts did not inhibit the activity of α-amylase, they were quite effective at inhibiting α-glucosidase, especially the unfermented Reishi extract, inhibiting 95.16% (at a concentration of 10 mg mL^-1) of α-glucosidase activity, which was slightly higher than the positive control at the same concentration. The most effective AChE inhibitor was unfermented green tea extract (68.51%), while the fermented coffee extract inhibited 34.66% of TYR activity at 10 mg mL^-1. Altogether, these results are in accordance with the differences found in the extracts' chemical composition. Finally, this is the first report that highlights the differences in the chemical profile between the unfermented and Kombucha fermented green tea, coffee and Reishi extracts, while it also reveals, for the first time, the antineurodegenerative potential of Kombucha fermented Reishi extract. The examined extracts represent potent functional foods, while their more detailed mechanisms of action are expected to be revealed in future research.

Vitamin C supplementation for diabetes management: A comprehensive narrative review

Growing evidence suggests that vitamin C supplementation may be an effective adjunct therapy in the management of people with diabetes. This paper critically reviews the current evidence on effects of vitamin C supplementation and its potential mechanisms in diabetes management. Evidence from meta-analyses of randomized controlled trials (RCTs) show favourable effects of vitamin C on glycaemic control and blood pressure that may be clinically meaningful, and mixed effects on blood lipids and endothelial function. However, evidence is mostly of low evidence certainty. Emerging evidence is promising for effects of vitamin C supplementation on some diabetes complications, particularly diabetic foot ulcers. However, there is a notable lack of robust and well-designed studies exploring effects of vitamin C as a single compound supplement on diabetes prevention and patient-important outcomes (i.e. prevention and amelioration of diabetes complications). RCTs are also required to investigate potential preventative or ameliorative effects of vitamin C on gestational diabetes outcomes. Oral vitamin C doses of 500-1000 mg per day are potentially effective, safe, and affordable for many individuals with diabetes. However, personalisation of supplementation regimens that consider factors such as vitamin C status, disease status, current glycaemic control, vitamin C intake, redox status, and genotype is important to optimize vitamin C's therapeutic effects safely. Finally, given a high prevalence of vitamin C deficiency in patients with complications, it is recommended that plasma vitamin C concentration be measured and monitored in the clinic setting.

Potential Diets to Improve Mitochondrial Activity in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease, the pathogenesis of which is based on alternations in the mitochondria of motor neurons, causing their progressive death. A growing body of evidence shows that more efficient mitophagy could prevent and/or treat this disorder by suppressing mitochondrial dysfunction-induced oxidative stress and inflammation. Mitophagy has been considered one of the main mechanisms responsible for mitochondrial quality control. Since ALS is characterized by enormous oxidative stress, several edible phytochemicals that can activate mitophagy to remove damaged mitochondria could be considered a promising option to treat ALS by providing neuroprotection. Therefore, it is of great significance to explore the mechanisms of mitophagy in ALS and to understand the effects and/or molecular mechanisms of phytochemical action, which could translate into a treatment for neurodegenerative diseases, including ALS.

The effect of evening primrose oil (Oenothera biennis) on the level of adiponectin and some biochemical parameters in rats with fructose induced metabolic syndrome

The effect of evening primrose oil on adiponectin level and some biochemical parameters in model of fructose-induced metabolic syndrome were investigated. The rats were divided into 4 groups: control, evening primrose oil, fructose, fructose + evening primrose oil. Body weight, daily feed and water consumptions and systolic blood pressures of animals were measured. At the end of trial, blood samples were taken, livers were excised and histopathological examination was performed. Glucose, uric acid, triglyceride, T.cholesterol, LDL, HDL, VLDL, ALT, AST, ALP, LDH, adiponectin, insulin, IL-6, TNF-α, TAC, and TOS levels were analysed. Some analysed parameters and systolic blood pressure of fructose + evening primrose oil group decreased significantly compared to fructose group and adiponectin, TAC, and HDL levels were significantly increased. As conclusion, evening primrose oil can be considered as antioxidant agent by reducing oxidative stress, increasing adiponectin levels and insulin sensitivity, anti-inflammatory properties, exhibiting anti-atherogenic effect by regulating dyslipidemia and systolic blood pressure.

The Nrf2 in Obesity: A Friend or Foe?

Obesity and its complications have become serious global health concerns recently and increasing work has been carried out to explicate the underlying mechanism of the disease development. The recognized correlations suggest oxidative stress and inflammation in expanding adipose tissue with excessive fat accumulation play important roles in the pathogenesis of obesity, as well as its associated metabolic syndromes. In adipose tissue, obesity-mediated insulin resistance strongly correlates with increased oxidative stress and inflammation. Nuclear factor erythroid 2-related factor 2 (Nrf2) has been described as a key modulator of antioxidant signaling, which regulates the transcription of various genes coding antioxidant enzymes and cytoprotective proteins. Furthermore, an increasing number of studies have demonstrated that Nrf2 is a pivotal target of obesity and its related metabolic disorders. However, its effects are controversial and even contradictory. This review aims to clarify the complicated interplay among Nrf2, oxidative stress, lipid metabolism, insulin signaling and chronic inflammation in obesity. Elucidating the implications of Nrf2 modulation on obesity would provide novel insights for potential therapeutic approaches in obesity and its comorbidities.

Herbal tea, a novel adjuvant therapy for treating type 2 diabetes mellitus: A review

Type 2 diabetes mellitus (T2DM) is a metabolic, endocrine disease characterized by persistent hyperglycemia. Several studies have shown that herbal tea improves glucose metabolism disorders in patients with T2DM. This study summarizes the published randomized controlled trials (RCTs) on herbal tea as a adjuvant therapy for treating T2DM and found that herbal teas have potential add-on effects in lowering blood glucose levels. In addition, we discussed the polyphenol contents in common herbal teas and their possible adverse effects. To better guide the application of herbal teas, we further summarized the hypoglycemic mechanisms of common herbal teas, which mainly involve: 1) improving insulin resistance, 2) protecting islet β-cells, 3) anti-inflammation and anti-oxidation, 4) inhibition of glucose absorption, and 5) suppression of gluconeogenesis. In conclusion, herbal tea, as a novel adjuvant therapy for treating T2DM, has the potential for further in-depth research and product development.

Association between Age-Related Macular Degeneration and the Risk of Diabetes Mellitus: A Nationwide Cohort Study

Age-related macular degeneration (AMD) is a degenerative and progressive disease of the macula, the part of the retina that is responsible for central vision. AMD shares some risk factors with diabetes mellitus (DM), but little is known about the risk of DM in individuals with AMD. With the goal of establishing novel perspectives, this study aimed to investigate the association between AMD and the risk of DM using the Korean Nationwide Health Insurance Database. Individuals aged ≥ 50 years who underwent a national health screening program in 2009 were enrolled. Participants were categorized by the presence of AMD and visual disability (VD). The Cox hazard regression model was used to examine hazard ratios (HRs) of DM with adjustment for potential confounders. Stratified analyses by age, sex, and comorbidities (hypertension or dyslipidemia) were also performed. During a mean follow-up of 8.61 years, there were 403,367 (11.76%) DM incidences among the final 3,430,532 participants. The crude HR (95% confidence interval (CI)) was 1.16 (1.13–1.20) for AMD. After adjusting for potential confounders, AMD was associated with a 3% decreased risk of DM (aHR 0.97, 95% CI 0.95–1.00), but no significant association with the risk of DM was found in AMD with VD (aHR 1.03, 95% CI 0.93–1.14). In summary, we did not find an increased risk of DM in individuals with AMD. A 3% decreased risk of DM in patients with AMD is not clinically meaningful. Our study suggests that the association between AMD and the risk of DM is weak, considering the potential confounders. Further studies examining this association are needed to extend our knowledge.

Abnormal Endometrial Receptivity and Oxidative Stress in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in women of childbearing age. Individual heterogeneity is evident, and the prevalence rate ranges between 6 and 15% globally. The prevalence rate of PCOS in Chinese women of childbearing age is 5.6%. The main manifestations are infertility, sparse menstruation, irregular vaginal bleeding, long-term endometrial hyperplasia, and endometrial cancer. PCOS is often associated with hyperandrogenemia, insulin resistance, hyperinsulinemia, obesity, metabolic syndrome, and intestinal flora disorder. Although there have been many studies in the past, the underlying pathophysiological mechanism of the disease is still unclear. Studies have shown that PCOS diseases and related complications are closely related to local oxidative stress imbalance in the endometrium, leading to poor endometrial receptivity and effects on pregnancy. Previous reviews have mainly focused on the abnormal mechanism of ovarian oxidative stress in women with PCOS, while reviews on endometrial receptivity and oxidative stress are relatively insufficient. This study reviews the abnormal cellular and molecular mechanisms of oxidative stress due to comorbidities in women with PCOS, leading to a downregulation of endometrial receptivity.

Resistance to Obesity in SOD1 Deficient Mice with a High-Fat/High-Sucrose Diet

Metabolic syndrome (Mets) is an important condition because it may cause stroke and heart disease in the future. Reactive oxygen species (ROSs) influence the pathogenesis of Mets; however, the types of ROSs and their localization remain largely unknown. In this study, we investigated the effects of SOD1, which localize to the cytoplasm and mitochondrial intermembrane space and metabolize superoxide anion, on Mets using SOD1 deficient mice (SOD1^−/−). SOD1^−/− fed on a high-fat/high-sucrose diet (HFHSD) for 24 weeks showed reduced body weight gain and adipose tissue size compared to wild-type mice (WT). Insulin secretion was dramatically decreased in SOD1^−/− fed on HFHSD even though blood glucose levels were similar to WT. Ambulatory oxygen consumption was accelerated in SOD1^−/− with HFHSD; however, ATP levels of skeletal muscle were somewhat reduced compared to WT. Reflecting the reduced ATP, the expression of phosphorylated AMPK (Thr 172) was more robust in SOD1^−/−. SOD1 is involved in the ATP production mechanism in mitochondria and may contribute to visceral fat accumulation by causing insulin secretion and insulin resistance.

The therapeutic effects and mechanisms of action of resveratrol on polycystic ovary syndrome: A comprehensive systematic review of clinical, animal, and in vitro studies

BACKGROUND

Polycystic ovary syndrome (PCOS) is one of the most important and common polygenic endocrine disorders among women of reproductive age. Resveratrol, a natural phenol, is involved in various biological activities, including antioxidant, antiseptic, anti-inflammatory, anti-aging, and anti-cancer effects.

METHODS

This systematic review aimed to investigate the therapeutic effects and mechanisms of actions of resveratrol in PCOS. The present study was conducted according to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements. We searched PubMed, Science Direct, Google Scholar, Scopus, ISI Web of Science, ProQuest, and Embase databases up to August 2021 by using the relative keywords. Original studies published in the English language that assessed the effects of resveratrol on PCOS and its associated complications were considered. Out of 417 records screened, only 24 articles met the inclusion criteria: 10 in vitro, 10 animal, and 4 human studies.

RESULTS

The results obtained in the present study showed that resveratrol supplementation might be effective in improving PCOS-related symptoms by reducing insulin resistance, alleviating dyslipidemia, improving ovarian morphology and anthropometric indices, regulating the reproductive hormones, and reducing inflammation and oxidative stress by affecting biological pathways.

CONCLUSION

According to the available evidence, resveratrol may reduce the complications of PCOS. However, further studies are recommended for a comprehensive conclusion on the exact mechanism of resveratrol in PCOS patients. This article is protected by copyright. All rights reserved.

Specialized Pro-Resolving Mediators Derived from N-3 Polyunsaturated Fatty Acids: Role in Metabolic Syndrome and Related Complications

Significance: Metabolic syndrome (MetS) prevalence continues to grow and represents a serious public health issue worldwide. This multifactorial condition carries the risk of hastening the development of type 2 diabetes (T2D), non-alcoholic fatty liver disease (NAFLD), and cardiovascular diseases (CVD). Another troubling aspect of MetS is the requirement of poly-pharmacological therapy not devoid of side effects. Therefore, there is an urgent need for prospecting alternative nutraceuticals as effective therapeutic agents for MetS. Recent Advances: Currently, there is an increased interest in understanding the regulation of metabolic derangements by specialized pro-resolving lipid mediators (SPMs), especially those derived from the long chain n-3 polyunsaturated fatty acids. Critical Issues: The SPMs are recognized as efficient modulators that are capable of inhibiting the production of pro-inflammatory cytokines, blocking neutrophil activation/recruitment, and inducing non-phlogistic (anti-inflammatory) activation of macrophage engulfment and removal of apoptotic inflammatory cells and debris. The aim of the present review is precisely to first underline key concepts relative to SPM functions before focusing on their status and actions on MetS components (e.g., obesity, glucose dysmetabolism, hyperlipidemia, hypertension) and complications such as T2D, NAFLD, and CVD. Future Directions: Valuable data from preclinical and clinical investigations have emphasized the SPM functions and influence on oxidative stress- and inflammation-related MetS. Despite these promising findings obtained without compromising host defense, additional efforts are needed to evaluate their potential therapeutic applications and further develop practical tools to monitor their bioavailability to cope with cardiometabolic disorders. Antioxid. Redox Signal. 37, 54-83.

Hepatic Insulin Resistance in Hyperthyroid Rat Liver: Vitamin E Supplementation Highlights a Possible Role of ROS

Thyroid hormones are normally involved in glycaemic control, but their excess can lead to altered glucose metabolism and insulin resistance (IR). Since hyperthyroidism-linked increase in ROS results in tissue oxidative stress that is considered a hallmark of conditions leading to IR, it is conceivable a role of ROS in the onset of IR in hyperthyroidism. To verify this hypothesis, we evaluated the effects of vitamin E on thyroid hormone-induced oxidative damage, insulin resistance, and on gene expression of key molecules involved in IR in the rat liver. The factors involved in oxidative damage, namely the total content of ROS, the mitochondrial production of ROS, the activity of antioxidant enzymes, the in vitro susceptibility to oxidative stress, have been correlated to insulin resistance indices, such as insulin activation of hepatic Akt and plasma level of glucose, insulin and HOMA index. Our results indicate that increased levels of oxidative damage ROS content and production and susceptibility to oxidative damage, parallel increased fasting plasma level of glucose and insulin, reduced activation of Akt and increased activation of JNK. This last result suggests a role for JNK in the insulin resistance induced by hyperthyroidism. Furthermore, the variation of the genes Pparg, Ppara, Cd36 and Slc2a2 could explain, at least in part, the observed metabolic phenotypes.

Early Prediction for Prediabetes and Type 2 Diabetes Using the Genetic Risk Score and Oxidative Stress Score

We aimed to use a genetic risk score (GRS) constructed with prediabetes and type 2 diabetes-related single nucleotide polymorphisms (SNPs) and an oxidative stress score (OSS) to construct an early-prediction model for prediabetes and type 2 diabetes (T2DM) incidence in a Korean population. The study population included 549 prediabetes and T2DM patients and 1036 normal subjects. The GRS was constructed using six prediabetes and T2DM-related SNPs, and the OSS was composed of three recognized oxidative stress biomarkers. Among the nine SNPs, six showed significant associations with the incidence of prediabetes and T2DM. The GRS was profoundly associated with increased prediabetes and T2DM (OR = 1.946) compared with individual SNPs after adjusting for age, sex, and BMI. Each of the three oxidative stress biomarkers was markedly higher in the prediabetes and T2DM group than in the normal group, and the OSS was significantly associated with increased prediabetes and T2DM (OR = 2.270). When BMI was introduced to the model with the OSS and GRS, the area under the ROC curve improved (from 69.3% to 70.5%). We found that the prediction model composed of the OSS, GRS, and BMI showed a significant prediction ability for the incidence of prediabetes and T2DM.

Effects of arbutin on glucose uptake by glucose transporter 4 (GLUT4) and its cytoprotective properties in L6 skeletal muscle cell line

It has been well known that oxidative stress and increased intracellular reactive oxygen species (ROS) have a pivotal role in disrupting the insulin signaling pathways leading to cellular insulin resistance. In this study, we evaluated arbutin's effects on glucose uptake by GLUT4 and cytoprotective properties in the L6 skeletal muscle cell line. The effect of arbutin and tertiary butyl hydrogen peroxide (t-BHP) on glucose uptake in cultured L6 cells was investigated by flow cytometry. We also evaluated gene expression levels of GLUT1 and GLUT4 in the L6 cells by quantitative real-time polymerase chain reaction analysis. The results from the study demonstrated that the optimum ROS generation occurred 3 h after 100 µM t-BHP treatment and pretreatment with arbutin (500 and 1000 µM) significantly inhibited the t-BHP induced ROS generation (p < .05). Our result indicated that 3 h pretreatment of L6 cells with 1000 μM of arbutin before 50 μM t-BHP significantly increased glucose uptake than the 50 μM t-BHP alone group (p < .05). Our findings may suggest that an increase in the uptake of 2-NBDG by L6 cells with arbutin pretreatment can be associated with increased expression of GLUT4 and GLUT1 under oxidative stress.

Oxidative stress in the pathophysiology of type 2 diabetes and related complications: Current therapeutics strategies and future perspectives

Type 2 diabetes (T2DM) is a persistent metabolic disorder rising rapidly worldwide. It is characterized by pancreatic insulin resistance and β-cell dysfunction. Hyperglycemia induced reactive oxygen species (ROS) production and oxidative stress are correlated with the pathogenesis and progression of this metabolic disease. To counteract the harmful effects of ROS, endogenous antioxidants of the body or exogenous antioxidants neutralise it and maintain bodily homeostasis. Under hyperglycemic conditions, the imbalance between the cellular antioxidant system and ROS production results in oxidative stress, which subsequently results in the development of diabetes. These ROS are produced in the endoplasmic reticulum, phagocytic cells and peroxisomes, with the mitochondrial electron transport chain (ETC) playing a pivotal role. The exacerbated ROS production can directly cause structural and functional modifications in proteins, lipids and nucleic acids. It also modulates several intracellular signaling pathways that lead to insulin resistance and impairment of β-cell function. In addition, the hyperglycemia-induced ROS production contributes to micro- and macro-vascular diabetic complications. Various in-vivo and in-vitro studies have demonstrated the anti-oxidative effects of natural products and their derived bioactive compounds. However, there is conflicting clinical evidence on the beneficial effects of these antioxidant therapies in diabetes prevention. This review article focused on the multifaceted role of oxidative stress caused by ROS overproduction in diabetes and related complications and possible antioxidative therapeutic strategies targeting ROS in this disease.

Peanut (Arachis hypogaea) sprout prevents high-fat diet-induced cognitive impairment by improving mitochondrial function

This study was performed to evaluate the improvement effect of the ethyl acetate fraction from peanut (Arachis hypogaea) sprout (EFPS) on high-fat diet (HFD)-induced cognitive deficits in C57BL/6 mice. Mice were randomly divided four groups (n = 13) as control (normal chow), HFD, EFPS 20 (20 mg/kg of body weight; intragastric administration) and EFPS 50 (50 mg/kg of body weight; intragastric administration) groups. HFD was provide for 15 weeks excepting control group. EFPS ameliorated cognitive dysfunction in Y-maze, passive avoidance test and Morris water maze test. EFPS significantly improved glucose tolerance and serum lipid profile, and reduced body weight. EFPS ameliorated oxidative stress by regulating MDA levels and SOD activity in liver and brain tissues. In addition, EFPS restored brain mitochondrial dysfunction related to energy metabolism. Moreover, the bioactive compounds of EFPS were identified as di-caffeic acid, caffeic acid, dihydrokaempferol-hexoside, di-p-coumaroyl tartaric acid isomer and group B soyasaponins using ultra-performance liquid chromatography-quadrupole-time-of-flight (UPLC-Q-TOF) mass spectrometry. These results show that EFPS can improve cognitive functions in HFD-induced diabetic mice.

Healthy versus Unhealthy Adipose Tissue Expansion: the Role of Exercise

Although the hallmark of obesity is the expansion of adipose tissue, not all adipose tissue expansion is the same. Expansion of healthy adipose tissue is accompanied by adequate capillary angiogenesis and mitochondria-centered metabolic integrity, whereas expansion of unhealthy adipose tissue is associated with capillary and mitochondrial derangement, resulting in deposition of immune cells (M1-stage macrophages) and excess production of pro-inflammatory cytokines. Accumulation of these dysfunctional adipose tissues has been linked to the development of obesity comorbidities, such as type 2 diabetes, hypertension, dyslipidemia, and cardiovascular disease, which are leading causes of human mortality and morbidity in modern society. Mechanistically, vascular rarefaction and mitochondrial incompetency (for example, low mitochondrial content, fragmented mitochondria, defective mitochondrial respiratory function, and excess production of mitochondrial reactive oxygen species) are frequently observed in adipose tissue of obese patients. Recent studies have demonstrated that exercise is a potent behavioral intervention for preventing and reducing obesity and other metabolic diseases. However, our understanding of potential cellular mechanisms of exercise, which promote healthy adipose tissue expansion, is at the beginning stage. In this review, we hypothesize that exercise can induce unique physiological stimuli that can alter angiogenesis and mitochondrial remodeling in adipose tissues and ultimately promote the development and progression of healthy adipogenesis. We summarize recent reports on how regular exercise can impose differential processes that lead to the formation of either healthy or unhealthy adipose tissue and discuss key knowledge gaps that warrant future research.

Oxidative RNA Damage in the Pathogenesis and Treatment of Type 2 Diabetes

Excessive production of free radicals can induce cellular damage, which is associated with many diseases. RNA is more susceptible to oxidative damage than DNA due to its single-stranded structure, and lack of protective proteins. Yet, oxidative damage to RNAs received little attention. Accumulating evidence reveals that oxidized RNAs may be dysfunctional and play fundamental role in the occurrence and development of type 2 diabetes (T2D) and its complications. Oxidized guanine nucleoside, 8-oxo-7, 8-dihydroguanine (8-oxoGuo) is a biomarker of RNA oxidation that could be associated with prognosis in patients with T2D. Nowadays, some clinical trials used antioxidants for the treatment of T2D, though the pharmacological effects remained unclear. In this review, we overview the cellular handling mechanisms and the consequences of the oxidative RNA damage for the better understanding of pathogenesis of T2D and may provide new insights to better therapeutic strategy.

Associations of neonicotinoids with insulin and glucose homeostasis parameters in US adults: NHANES 2015-2016

Neonicotinoids are replacement insecticides increasingly used for organophosphates, methylcarbamates, and pyrethroids. Experimental evidence suggests neonicotinoids may affect glucose metabolism and insulin secretion through pancreatic β cell dysfunction, oxidative stress, and inflammation. However, no epidemiologic study has investigated neonicotinoids as potential diabetogens. We examined associations between neonicotinoids with insulin and glucose homeostasis parameters among 1381 non-diabetic adults in the National Health and Nutrition Examination Survey (2015-2016). Urinary concentrations of acetamiprid, clothianidin, imidacloprid, N-desmethyl-acetamiprid, and 5-hydroxy-imidacloprid were quantified. Fasting plasma glucose, insulin, and hemoglobin A_1c (HbA_1c) were assessed. Insulin resistance was defined as a homeostatic model assessment of insulin resistance ≥2.5. We used weighted linear and logistic regression to estimate associations between detectable neonicotinoids with insulin and glucose homeostasis parameters compared to non-detectable neonicotinoid concentrations. Weighted detection frequencies for imidacloprid, 5-hydroxy-imidacloprid, and N-desmethyl-acetamiprid were 4.4 %, 21.5 %, and 32.8 %, respectively. Detectable imidacloprid (β = -4.7 μIU/mL, 95 % confidence interval [CI] -8.5, -0.8) and 5-hydroxy-imidacloprid (β = -2.4 μIU/mL, 95 % CI -4.6, -0.2) were associated with lower fasting plasma insulin levels. Individuals with detectable 5-hydroxy-imidacloprid had lower odds of insulin resistance (odds ratio [OR] = 0.3, 95 % CI 0.2, 0.7). We observed evidence of sexually dimorphic associations between N-desmethyl-acetamiprid with glucose (p_int = 0.079) and 5-hydroxy-imidacloprid with HbA_1c (p_int = 0.038), with patterns suggesting positive associations in males and negative associations in females. Associations between 5-hydroxy-imidacloprid and insulin were modified by body mass index (BMI) (p_int = 0.013). We additionally observed age modified associations between 5-hydyroxy-imidacloprid and glucose (p_int = 0.048). Results suggest neonicotinoids may be associated with insulin and glucose homeostasis indices and call for prospective studies to examine the metabolic impact of these replacement insecticides in humans.

Chlordane exposure causes developmental delay and metabolic disorders in Drosophila melanogaster

The incidence of metabolic diseases is increasing every year, and several studies have highlighted the activity of persistent organic pollutants (POPs) in causing hyperlipidemia and diabetes, and these compounds are considered to be endocrine disrupting chemicals (EDCs). Chlordane is classified as an endocrine disruptor, but the mechanism of how it functions is still unclear. This study investigates the effects of chlordane exposure on Drosophila larvae. Drosophila was cultured in diet containing 0.01 μM, 0.1 μM, 1 μM, 5 μM, and 10 μM chlordane, and the toxicity of chlordane, the growth and development of Drosophila, the homeostasis of glucose and lipid metabolism and insulin signaling pathway, lipid peroxidation-related indicators and Nrf2 signaling pathway were evaluated. We here found that exposure to high concentrations of chlordane decreased the survival rate of Drosophila and that exposure to low concentrations of chlordane caused disruption of glucose and lipid metabolism, increased insulin secretion and impairment of insulin signaling. Notably, it also led to massive ROS production and lipid peroxidation despite of the activation of Nrf2 signaling pathway, an important pathway for maintaining redox homeostasis. Collectively, chlordane causes lipid peroxidation and disrupts redox homeostasis, which may be a potential mechanism leading to impaired insulin signaling and the metabolism of glucose and lipid, ultimately affects Drosophila development.

Acylated anthocyanins: A review on their bioavailability and effects on postprandial carbohydrate metabolism and inflammation

Anthocyanins, the natural red and purple colorants of berries, fruits, vegetables, and tubers, improve carbohydrate metabolism and decrease the risk factors of metabolic disorders, but their industrial use is limited by their chemical instability. Acylation of the glycosyl moieties of anthocyanins, however, changes the chemical properties of anthocyanins and provides enhanced stability. Thus, acylated anthocyanins are more usable as natural colorants and bioactive components of innovative functional foods. Acylated anthocyanins are common in pigmented vegetables and tubers, the consumption of which has the potential to increase the intake of health-promoting anthocyanins as part of the daily diet. For the first time, this review presents the current findings on bioavailability, absorption, metabolism, and health effects of acylated anthocyanins with comparison to more extensively investigated nonacylated anthocyanins. The structural differences between nonacylated and acylated anthocyanins lead to enhanced color stability, altered absorption, bioavailability, in vivo stability, and colonic degradation. The impact of phenolic metabolites and their potential health effects regardless of the low bioavailability of the parent anthocyanins as such is discussed. Here, purple-fleshed potatoes are presented as a globally available, eco-friendly model food rich in acylated anthocyanins, which further highlights the industrial possibilities and nutritional relevance of acylated anthocyanins. This work supports the academic community and industry in food research and development by reviewing the current literature and highlighting gaps of knowledge.

Association between the Serum Coenzyme Q10 Level and Seizure Control in Patients with Drug-Resistant Epilepsy

Drug-resistant epilepsy (DRE) is a chronic neurological disorder with somatic impacts and increased risk of metabolic comorbidities. Oxidative stress might play an important role in metabolic effects and as a regulator of seizure control, while coenzyme Q10 (CoQ10) could improve insulin sensitivity through antioxidant effects. We aimed to investigate the association between CoQ10 level and clinical outcome, represented by the seizure frequency and quality of life, in DRE patients. DRE patients (N = 33) had significantly higher serum insulin levels and lower scores on the physical domain of the World Health Organization Quality of Life questionnaire (WHOQoL) than gender-age matched controls. The serum CoQ10 level (2910.4 ± 1163.7 ng/mL) was much higher in DRE patients than the normal range. Moreover, the serum CoQ10 level was significantly correlated with the seizure frequency (r = −0.412, p = 0.037) and insulin level (r = 0.409, p = 0.038). Based on stratification by insulin resistance (HOMA-IR > 2.4), the subgroup analysis showed that patients with a greater HOMA-IR had higher CoQ10 levels and lower seizure frequency, and had a significantly worse quality of life. In summary, CoQ10 could be a mediator involved in the mechanism of epilepsy and serve as a biomarker of the clinical outcome in DER patients.

Phytochemicals: Targeting Mitophagy to Treat Metabolic Disorders

Metabolic disorders include metabolic syndrome, obesity, type 2 diabetes mellitus, non-alcoholic fatty liver disease and cardiovascular diseases. Due to unhealthy lifestyles such as high-calorie diet, sedentary and physical inactivity, the prevalence of metabolic disorders poses a huge challenge to global human health, which is the leading cause of global human death. Mitochondrion is the major site of adenosine triphosphate synthesis, fatty acid β-oxidation and ROS production. Accumulating evidence suggests that mitochondrial dysfunction-related oxidative stress and inflammation is involved in the development of metabolic disorders. Mitophagy, a catabolic process, selectively degrades damaged or superfluous mitochondria to reverse mitochondrial dysfunction and preserve mitochondrial function. It is considered to be one of the major mechanisms responsible for mitochondrial quality control. Growing evidence shows that mitophagy can prevent and treat metabolic disorders through suppressing mitochondrial dysfunction-induced oxidative stress and inflammation. In the past decade, in order to expand the range of pharmaceutical options, more and more phytochemicals have been proven to have therapeutic effects on metabolic disorders. Many of these phytochemicals have been proved to activate mitophagy to ameliorate metabolic disorders. Given the ongoing epidemic of metabolic disorders, it is of great significance to explore the contribution and underlying mechanisms of mitophagy in metabolic disorders, and to understand the effects and molecular mechanisms of phytochemicals on the treatment of metabolic disorders. Here, we investigate the mechanism of mitochondrial dysfunction in metabolic disorders and discuss the potential of targeting mitophagy with phytochemicals for the treatment of metabolic disorders, with a view to providing a direction for finding phytochemicals that target mitophagy to prevent or treat metabolic disorders.

Insulin Resistance Exacerbates Alzheimer Disease via Multiple Mechanisms

Alzheimer disease (AD) is a chronic neurodegenerative disease that accounts for 60–70% of dementia and is the sixth leading cause of death in the United States. The pathogenesis of this debilitating disorder is still not completely understood. New insights into the pathogenesis of AD are needed in order to develop novel pharmacologic approaches. In recent years, numerous studies have shown that insulin resistance plays a significant role in the development of AD. Over 80% of patients with AD have type II diabetes (T2DM) or abnormal serum glucose, suggesting that the pathogenic mechanisms of insulin resistance and AD likely overlap. Insulin resistance increases neuroinflammation, which promotes both amyloid β-protein deposition and aberrant tau phosphorylation. By increasing production of reactive oxygen species, insulin resistance triggers amyloid β-protein accumulation. Oxidative stress associated with insulin resistance also dysregulates glycogen synthase kinase 3-β (GSK-3β), which leads to increased tau phosphorylation. Both insulin and amyloid β-protein are metabolized by insulin degrading enzyme (IDE). Defects in this enzyme are the basis for a strong association between T2DM and AD. This review highlights multiple pathogenic mechanisms induced by insulin resistance that are implicated in AD. Several pharmacologic approaches to AD associated with insulin resistance are presented.

Short-term high fat diet alters genes associated with metabolic and vascular dysfunction during adolescence in rats: a pilot study

Background

Diet-induced metabolic dysfunction precedes multiple disease states including diabetes, heart disease, and vascular dysfunction. The critical role of the vasculature in disease progression is established, yet the details of how gene expression changes in early cardiovascular disease remain an enigma. The objective of the current pilot project was to evaluate whether a quantitative assessment of gene expression within the aorta of six-week old healthy male Sprague-Dawley rats compared to those exhibiting symptoms of metabolic dysfunction could reveal potential mediators of vascular dysfunction.

Methods

RNA was extracted from the aorta of eight rats from a larger experiment; four animals fed a high-fat diet (HFD) known to induce symptoms of metabolic dysfunction (hypertension, increased adiposity, fasting hyperglycemia) and four age-matched healthy animals fed a standard chow diet (CHOW). The bioinformatic workflow included Gene Ontology (GO) biological process enrichment and network analyses.

Results

The resulting network contained genes relevant to physiological processes including fat and protein metabolism, oxygen transport, hormone regulation, vascular regulation, thermoregulation, and circadian rhythm. The majority of differentially regulated genes were downregulated, including several associated with circadian clock function. In contrast, leptin and 3-hydroxy-3-methylglutaryl-CoA synthase 2 (Hmgcs2) were notably upregulated. Leptin is involved in several major energy balance signaling pathways and Hmgcs2 is a mitochondrial enzyme that catalyzes the first reaction of ketogenesis.

Conclusion

Together, these data describe changes in gene expression within the aortic wall of HFD rats with early metabolic dysfunction and highlight potential pathways and signaling intermediates that may impact the development of early vascular dysfunction.

Lasting Effects of Low to Non-Lethal Radiation Exposure during Late Gestation on Offspring's Cardiac Metabolism and Oxidative Stress

Ionizing radiation (IR) is known to cause fetal programming, but the physiological effects of low-dose IR are not fully understood. This study examined the effect of low (50 mGy) to non-lethal (300 and 1000 mGy) radiation exposure during late gestation on cardiac metabolism and oxidative stress in adult offspring. Pregnant C57BL/6J mice were exposed to 50, 300, or 1000 mGy of gamma radiation or Sham irradiation on gestational day 15. Sixteen weeks after birth, ¹⁸F-Fluorodeoxyglucose (FDG) uptake was examined in the offspring using Positron Emission Tomography imaging. Western blot was used to determine changes in oxidative stress, antioxidants, and insulin signaling related proteins. Male and female offspring from irradiated dams had lower body weights when compared to the Sham. 1000 mGy female offspring demonstrated a significant increase in ¹⁸F-FDG uptake, glycogen content, and oxidative stress. 300 and 1000 mGy female mice exhibited increased superoxide dismutase activity, decreased glutathione peroxidase activity, and decreased reduced/oxidized glutathione ratio. We conclude that non-lethal radiation during late gestation can alter glucose uptake and increase oxidative stress in female offspring. These data provide evidence that low doses of IR during the third trimester are not harmful but higher, non-lethal doses can alter cardiac metabolism later in life and sex may have a role in fetal programming.

Maternal Apical Periodontitis Increases Insulin Resistance and Modulates the Antioxidant Defense System in the Gastrocnemius Muscle of Adult Offspring

INTRODUCTION

Maternal apical periodontitis (AP) is associated with insulin resistance (IR) in adult offspring. Oxidative stress has been linked to IR. This study investigated insulin sensitivity (IS) and oxidative stress in the gastrocnemius muscle (GM) of adult offspring of rats with AP.

METHODS

Fifteen female Wistar rats were distributed into a control group, a group with 1 tooth with AP, and a group with 4 teeth with AP. Thirty days after AP induction, female rats were mated with healthy male rats. When male offspring reached 75 days of age, glycemia, insulinemia, and IS were determined. In the GM, the oxidative damage products (thiobarbituric acid reactive substances and carbonyl protein) and activities of enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) and nonenzymatic (glutathione and total antioxidant capacity) antioxidants were quantified. Analysis of variance was performed followed by the Tukey post hoc test (P < .05).

RESULTS

Maternal AP was associated with decreased IS and changes in antioxidant activities (reduced superoxide dismutase and increased catalase, glutathione peroxidase, and glutathione) and decreased thiobarbituric acid reactive substance concentration in the GM of their adult offspring. However, maternal AP does not appear to affect glycemia, carbonyl protein concentration, and the nonenzymatic total antioxidant capacity in the GM of this offspring.

CONCLUSIONS

Maternal AP modulates the antioxidant defense system in the GM of their adult offspring, attenuating lipid peroxidation in this tissue. This reflects part of an adaptive response of the offspring to the stimulation of the maternal chronic oral inflammatory process in which the organism acts by decreasing oxidative tissue damage in the postnatal stage. The present study improves knowledge about the impact of maternal oral inflammation on healthy offspring.

Contribution of Adipose Tissue Oxidative Stress to Obesity-Associated Diabetes Risk and Ethnic Differences: Focus on Women of African Ancestry

Adipose tissue (AT) storage capacity is central in the maintenance of whole-body homeostasis, especially in obesity states. However, sustained nutrients overflow may dysregulate this function resulting in adipocytes hypertrophy, AT hypoxia, inflammation and oxidative stress. Systemic inflammation may also contribute to the disruption of AT redox equilibrium. AT and systemic oxidative stress have been involved in the development of obesity-associated insulin resistance (IR) and type 2 diabetes (T2D) through several mechanisms. Interestingly, fat accumulation, body fat distribution and the degree of how adiposity translates into cardio-metabolic diseases differ between ethnicities. Populations of African ancestry have a higher prevalence of obesity and higher T2D risk than populations of European ancestry, mainly driven by higher rates among African women. Considering the reported ethnic-specific differences in AT distribution and function and higher levels of systemic oxidative stress markers, oxidative stress is a potential contributor to the higher susceptibility for metabolic diseases in African women. This review summarizes existing evidence supporting this hypothesis while acknowledging a lack of data on AT oxidative stress in relation to IR in Africans, and the potential influence of other ethnicity-related modulators (e.g., genetic-environment interplay, socioeconomic factors) for consideration in future studies with different ethnicities.

Sleeping Duration, Napping and Snoring in Association with Diabetes Control among Patients with Diabetes in Qatar

BACKGROUND

Poor glycemic control is associated with chronic life-threatening complications. Several studies have revealed that sleep status is associated with glycemic control.

AIM

to examine the association between sleep duration, quality and glycemic control among adults with diabetes.

METHODS

Data on 2500 participants aged 18-60 years were collected from the Qatar Biobank (QBB). Sleep duration and quality were assessed by a self-completed health and lifestyle questionnaire, and glycemic control was assessed using HbA1c. Logistic regression was used to assess the association between sleep duration, napping, snoring and poor glycemic control.

RESULTS

After adjusting for age and gender, sleep duration was not associated with poor glycemic control. Lack of association persisted after controlling for smoking, physical activity, education, BMI, fruit and vegetable intake, insulin and medication use. However, sleeping for long hours at night (≥8 h) had a trend in increasing the risk of poor glycemic control (OR = 1.28; 95% CI: 0.94-1.74). Napping was positively associated with poor glycemic control. After adjusting for age and gender, patients who reported "sometimes, frequently, or always" napping had more than 30% increased risk of poor control as compared to patients who reported "never/rarely" napping. Snoring was not associated with poor glycemic control among the study sample when adjusted for age and gender (p = 0.61). Other factors were found to be associated with a better glycemic control such as female, high educational and high physical activity level.

CONCLUSIONS

our results suggest that napping may be an independent risk factor for a poor glycemic control in diabetes; further investigations are required.