Markers of Antioxidant Defense in Patients with Type 2 Diabetes

Gypenoside A-loaded mPEG-PLGA nanoparticles ameliorate high-glucose-induced retinal microvasculopathy by inhibiting ferroptosis

Diabetic retinopathy (DR) is one of the chronic microvascular complications of type 2 diabetes mellitus (T2DM), which will cause retinal detachment and blindness without ideal therapies. Gypenoside A (GPA) are the main bioactive compound from Gynostemma pentaphyllum, and have various pharmacological effects. However, it suffered from poor bioavailability and potential cardiotoxicity in the clinical application. To overcome those limitations, in this study, nearly spherical nanoparticles (GPA-NP) with a mean particle size of 140.6 ± 22.4 nm were prepared by encapsulating GPA into mPEG-PLGA. This encapsulation efficiency was 84.4 ± 6.9 %, and the drug load was 4.02 %±0.35 %. The results showed that GPA-NP displayed more prolonged GPA release and higher bioavailability in vitro than GPA. GPA-NP obviously reduced the levels of oxidative stress markers and inflammatory cytokines in both retinal tissues of DR mice and high glucose-exposed HRMEC better than GPA alone. Mechanismly, GPA blocked the Nrf2-Keap1 interaction by binding with Kelch domain of Keap1 via alkyl and hydrogen bonds. Therefore, GPA-NP exerted more potent protectivity effects against high glucose-induced retinal microvascular endothelial ferroptosis in vitro and in vivo by activating Nrf2/HO-1/GPX4 pathway. It could be a promising therapeutic agent for preventing DR.

Therapeutic Effects of Nigella sativa Oil and Whole Seeds on STZ-Induced Diabetic Rats: A Biochemical and Immunohistochemical Study

Background

Type II diabetes mellitus (DM) is an increasing health problem that has negative impacts on patients and healthcare systems, worldwide. The development of new therapies with better efficacy, fewer side effects, and lower prices are urgently needed to treat this disease.

Aim

To evaluate and compare the therapeutic effects of Nigella sativa (N. sativa) seed and oil on the biochemical parameters and regeneration of pancreatic islets (or islets of Langerhans) of streptozotocin (STZ)-induced diabetic rats.

Materials and Methods

The diabetic rat model was prepared by administering a single dose of STZ (35 mg/kg body weight). The whole seed or the oil of N. sativa was administered to the diabetic and control groups for a period of 28 days, but not to the negative and STZ controls. Serum blood glucose, liver enzymes, lipid profile, and renal function tests (uric acid, albumin, total protein, urea, and creatinine) were measured in all groups. After the rats were euthanized, their pancreases were extracted, and then sectioned and fixed on slides in preparation before staining with H&E stain and immunohistochemical study.

Results

Treatment of STZ-diabetic rats with N. sativa seeds or oil significantly improved their serum glucose levels, lipid profiles, and liver and renal functions as well as preserved the integrity of pancreatic β cells.

Conclusion

N. sativa seeds and oil demonstrate significant therapeutic improvement effects on DM and its related complications including effective protection of islets of Langerhans. The therapeutic benefits of N. sativa seeds and oil on DM and its related complications are comparable.

Pancreatic β-Cell Identity Change through the Lens of Single-Cell Omics Research

The main hallmark in the development of both type 1 and type 2 diabetes is a decline in functional β-cell mass. This decline is predominantly attributed to β-cell death, although recent findings suggest that the loss of β-cell identity may also contribute to β-cell dysfunction. This phenomenon is characterized by a reduced expression of key markers associated with β-cell identity. This review delves into the insights gained from single-cell omics research specifically focused on β-cell identity. It highlights how single-cell omics based studies have uncovered an unexpected level of heterogeneity among β-cells and have facilitated the identification of distinct β-cell subpopulations through the discovery of cell surface markers, transcriptional regulators, the upregulation of stress-related genes, and alterations in chromatin activity. Furthermore, specific subsets of β-cells have been identified in diabetes, such as displaying an immature, dedifferentiated gene signature, expressing significantly lower insulin mRNA levels, and expressing increased β-cell precursor markers. Additionally, single-cell omics has increased insight into the detrimental effects of diabetes-associated conditions, including endoplasmic reticulum stress, oxidative stress, and inflammation, on β-cell identity. Lastly, this review outlines the factors that may influence the identification of β-cell subpopulations when designing and performing a single-cell omics experiment.

Low Antioxidant Enzyme Levels and Oxidative Stress in Laryngopharyngeal Reflux (LPR) Patients

OBJECTIVE

Laryngopharyngeal reflux disease (LPR) is a characterized by symptoms different from gastroesophageal reflux disease (GERD). LPR can causes chronic mucosal inflammation which may lead to an increase in cytokine production, and a systemic decrease in antioxidant enzyme levels. Our aim in this study is to evaluate antioxidant enzyme levels in patients with LPR.

METHODS

Reflux Symptom Index (RSI) questionnaire, extraesophageal symptom questionnaire which is included in RSI and Reflux Finding Score (RFS) evaluation with 70° rigid laryngoscope were performed to patients who applied to the otolaryngology clinic with a typical LPR complaint, and 60 patients who had an RSI score above 13 and an RFS score above 7 were included in the study. Thirty people consisting of healthy volunteers were included in the control group. Antioxidant enzyme SOD, GSH-Px and CAT levels were measured in the blood serum of the patients and compared with the control group. Results obtained from biochemical tests were expressed as mean ± SE. Descriptive statistical methods (mean ± standard error) were used for the independent t test for the control and study group. P < 0.05 was considered statistically significant.

RESULTS

In the LPR group, 28 (46%) were women, 32 (53%) were men, and age range was 21-60, average age was 36.45 ± 1.147.There was no significant difference between LPR and control group in terms of age, gender and Body Mass Index (BMI). In the LPR group, the lowest score for RSI was 14 and the highest score was 39. The average RSI was 23.67. RFS ranges from 8-22. The mean RFS was 13.50. A highly significant statistical correlation was observed between RSI and total RFS (P < 0.001). There was a significant difference between the antioxidant enzyme levels of the control group and the LPR group. Antioxidant enzyme levels of the control group were SOD 274.10 ± 26.836 U / L, GSH-Px 174.20 ± 20.699 µU / mL and CAT 42.2898 ± 20.699 KU / L. Antioxidant enzyme level results of the LPR group were SOD 147 ± 14.022 U / L (P < 0.01), GSH-Px 88.28 ± 9.113 µU / mL (P < 0.01) and CAT 12.67 ± 0.799 KU / L (P < 0.001). The RSI results ranges from 4 to 39 and the RFS from 8 to 22. Antioxidant enzyme levels demonstrated fairly consistent reliability with individual variables from both RFS and RFS. There was also a highly significant statistical correlation between RSI and RFS.

CONCLUSION

We found that the antioxidant enzymes SOD, GPX and catalase enzyme levels were significantly lower in LPR patients. Treatment modalities to reduce oxidative stress (OS) in LPR should be investigated.

Reactive X (where X = O, N, S, C, Cl, Br, and I) species nanomedicine

Reactive oxygen, nitrogen, sulfur, carbonyl, chlorine, bromine, and iodine species (RXS, where X = O, N, S, C, Cl, Br, and I) have important roles in various normal physiological processes and act as essential regulators of cell metabolism; their inherent biological activities govern cell signaling, immune balance, and tissue homeostasis. However, an imbalance between RXS production and consumption will induce the occurrence and development of various diseases. Due to the considerable progress of nanomedicine, a variety of nanosystems that can regulate RXS has been rationally designed and engineered for restoring RXS balance to halt the pathological processes of different diseases. The invention of radical-regulating nanomaterials creates the possibility of intriguing projects for disease treatment and promotes advances in nanomedicine. In this comprehensive review, we summarize, discuss, and highlight very-recent advances in RXS-based nanomedicine for versatile disease treatments. This review particularly focuses on the types and pathological effects of these reactive species and explores the biological effects of RXS-based nanomaterials, accompanied by a discussion and the outlook of the challenges faced and future clinical translations of RXS nanomedicines.

Oral Glucose Tolerance Test (OGTT) Evidence for the Postprandial Anti-Hyperglycemic Property of Salacca zalacca (Gaertn.) Voss Seed Extract

Salak seed extract (Salacca zalacca) is known for its high antioxidant content and low caffeine levels, making it a promising candidate for the development of value-added health products. However, there is a lack of scientific evidence for its anti-hyperglycemic effects. To address this, we investigated the in vitro and in vivo anti-hyperglycemic and antioxidant effects of salak seed extract. The HPLC chromatogram of salak seed extract shows a prominent peak that corresponds to chlorogenic acid. In vitro studies revealed that salak seeds inhibited α-glucosidase activity and glucose uptake in Caco-2 cells in a concentration-dependent manner, while also exhibiting antioxidant properties. The extract exhibits a non-competitive inhibition on α-glucosidase activity, with an IC50 and Ki of 16.28 ± 7.22 and 24.81 μg/mL, respectively. In vivo studies utilizing streptozotocin-nicotinamide-induced diabetic mice showed that the extract significantly reduced fasting blood glucose (FBG) levels in the oral glucose tolerance test. Continuous administration of the salak seed extract resulted in lower FBG levels by 13.8% as compared with untreated diabetic mice, although this change was not statistically significant. The estimated LD50 value of salak seed extract exceeds 2000 mg/kg, and no toxicity symptoms have been detected. Our research supports that salak seed extract has the potential to serve as a functional food or supplement that may be beneficial in reducing postprandial hyperglycemia among people with type 2 diabetes. This effect was explained by the salak's inhibitory mechanisms of glucose absorption due to inhibition of both α-glucosidase activity and intestinal glucose uptake, coupled with its antioxidant effects.

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.

Clinical Relevance of lncRNA and Mitochondrial Targeted Antioxidants as Therapeutic Options in Regulating Oxidative Stress and Mitochondrial Function in Vascular Complications of Diabetes

Metabolic imbalances and persistent hyperglycemia are widely recognized as driving forces for augmented cytosolic and mitochondrial reactive oxygen species (ROS) in diabetes mellitus (DM), fostering the development of vascular complications such as diabetic nephropathy, diabetic cardiomyopathy, diabetic neuropathy, and diabetic retinopathy. Therefore, specific therapeutic approaches capable of modulating oxidative milieu may provide a preventative and/or therapeutic benefit against the development of cardiovascular complications in diabetes patients. Recent studies have demonstrated epigenetic alterations in circulating and tissue-specific long non-coding RNA (lncRNA) signatures in vascular complications of DM regulating mitochondrial function under oxidative stress. Intriguingly, over the past decade mitochondria-targeted antioxidants (MTAs) have emerged as a promising therapeutic option for managing oxidative stress-induced diseases. Here, we review the present status of lncRNA as a diagnostic biomarker and potential regulator of oxidative stress in vascular complications of DM. We also discuss the recent advances in using MTAs in different animal models and clinical trials. We summarize the prospects and challenges for the use of MTAs in treating vascular diseases and their application in translation medicine, which may be beneficial in MTA drug design development, and their application in translational medicine.

Modeling type 2 diabetes in rats by administering tacrolimus

The prevalence of diabetes is rapidly increasing. The current number of diagnosed cases is ~422 million, expected to reach ~640 million by 2040. Type 2 diabetes, which constitutes ~95% of the cases, is characterized by insulin resistance and a progressive loss of β-cell function. Despite intense research efforts, no treatments are yet able to cure the disease or halt its progression. Since all existing animal models of type 2 diabetes have serious drawbacks, one is needed that represents the complete pathogenesis, is low cost and non-obese, and can be developed relatively quickly. The aim of this study was to evaluate a low-cost, non-obese model of type 2 diabetes engendered by administering a daily high dose of tacrolimus (an immunosuppressant) to Wistar rats for 4 weeks. The biochemical and antioxidant markers were measured at basal and after the 4-week tacrolimus treatment. At week 4, the values of these parameters closely resembled those observed in human type 2 diabetes, including fasting blood glucose at 141.5 mg/dL, blood glucose greater than 200 mg/dL at 120 min of the glucose tolerance test, blood glucose at varied levels in the insulin tolerance test, and elevated levels of cholesterol and triglyceride. The tacrolimus treatment produced hypoinsulinemia and sustained hyperglycemia, probably explained by the alteration found in pancreatic β-cell function and morphology. This model should certainly be instrumental for evaluating possible type 2 diabetes treatments, and for designing new immunosuppressants that do not cause pancreatic damage, type 2 diabetes, or new-onset diabetes after transplantation (NODAT).

Increased mitochondrial proton leak and glycolysis in peripheral blood mononuclear cells in type-1-diabetes

Changes in cellular bioenergetics such as mitochondrial respiration and glycolysis may play a role in the pathogenesis of various diseases including type 1 diabetes (T1D). We used Seahorse extracellular flux technology to analyse the efficiency of glycolysis and mitochondrial oxidative phosphorylation in peripheral blood mononuclear cells (PBMCs) obtained from fresh blood samples from fifteen long-term T1D individuals with albuminuria (five females) with an average (±SD) age of 58 (±14) years and 15 age and sex-matched healthy non-diabetic controls. In T1D PBMCs, mitochondrial proton leak was higher (T1D: 21,3 ± 1,46 pmol/min; controls: 17,3 ± 1,24 pmol/min; p = 0,049) and glucose (5 mM) suppressed mitochondrial proton leak more than in healthy controls. Further, PBMCs from T1D individuals had higher glycolysis compared with healthy controls (T1D: 9,68 ± 0,94 mpH/min; controls: 7,07 ± 0,64 mpH/min; p = 0,032). Correlation analysis of circulating inflammatory factors identified Leukaemia Inhibitor factor 1 (LIF) being negatively correlated with PBMC glycolysis. Our results suggest that mitochondrial and glycolytic pathways of PBMCs from long-term T1D individuals with albuminuria might be dysfunctional, possibly due to increased cellular metabolic load and/or oxidative stress in which inflammatory factors could play a role.

Traditional chinese medicine to prevent and treat diabetic erectile dysfunction

Diabetic erectile dysfunction (DED) is one of the most common complications of diabetes mellitus. However, current therapeutics have no satisfactory effect on DED. In recent years, traditional Chinese medicine (TCM) has shown good effects against DED. By now, several clinical trials have been conducted to study the effect of TCM in treating DED; yet, the underlying mechanism is not fully investigated. Therefore, in this review, we briefly summarized the pathophysiological mechanism of DED and reviewed the published clinical trials on the treatment of DED by TCM. Then, the therapeutic potential of TCM and the underlying mechanisms whereby TCM exerts protective effects were summarized. We concluded that TCM is more effective than chemical drugs in treating DED by targeting multiple signaling pathways, including those involved in oxidation, apoptosis, atherosclerosis, and endothelial function. However, the major limitation in the application of TCM against DED is the lack of a large-scale, multicenter, randomized, and controlled clinical trial on the therapeutic effect, and the underlying pharmaceutical mechanisms also need further investigation. Despite these limitations, clinical trials and further experimental studies will enhance our understanding of the mechanisms modulated by TCM and promote the widespread application of TCM to treat DED.

Independent Association of 25[OH]D Level on Reduced Glutathione and TNF-α in Patients ‎with Diabetes and/or Hypertension

Purpose

Oxidative and inflammatory pathways play a significant role in the pathophysiology of a wide variety of non-communicable diseases such as type 2 diabetes mellitus (T2DM) and hypertension. However, the effect of serum 25-hydroxyvitamin D ‎‎(25[OH]D) on these pathways is still controversial. To evaluate the association of 25[OH]D on ‎antioxidant and pro-inflammatory biomarkers, reduced glutathione (GSH) and tumor ‎necrosis factor (TNF)-α, in T2DM and hypertensive patients.

Patients and Methods

This is a cross-sectional study of a consecutive sample of patients attending the the Family Medicine clinic at King Abdullah bin Abdulaziz University Hospital (KAAUH). Participants were screened for eligibility according to the following ‎criteria: aged above 18 years and diagnosed with T2DM and/or hypertension for at least one ‎year. Patients receiving any kind of vitamin D or calcium supplements within the last three ‎months were excluded, as were those with a history of ‎renal failure, cancer, liver, thyroid, or any other chronic inflammatory diseases.

Results

In total 424 T2DM and/or ‎hypertensive patients (mean age 55±12 years) were recruited. In addition to routine ‎physical and laboratory examinations, levels of serum 25[OH]D, GSH and TNF-α were ‎measured. The prevalence of 25[OH]D deficiency (<50 nmol/L) was 35.1%, which was ‎independent from GSH and TNF-α levels. In T2DM, hypertensive and patients having ‎both diseases, GSH levels were 349.3±19, 355.4±19 and 428.8±20 μmol/L, ‎respectively. Uncontrolled T2DM and hypertension patients showed significantly higher ‎GSH compared with the controlled group. ‎Males showed slightly higher level ‎of TNF-α compared with females and uncontrolled hypertensive patients had relatively ‎higher TNF-α level when evaluated against controlled hypertensive patients. ‎

Conclusion

25[OH]D level is independent of oxidative stress and inflammation, ‎assessed by levels of GSH and TNF-α, respectively, in T2DM and hypertensive Saudi ‎patients. ‎

Preclinical insights into fucoidan as a nutraceutical compound against perfluorooctanoic acid-associated obesity via targeting endoplasmic reticulum stress

Obesity is a growing global health problem; it has been forecasted that over half of the global population will be obese by 2030. Obesity is complicated with many diseases, such as diabetes and cardiovascular diseases, leading to an economic impact on society. Other than diet, exposure to environmental pollutants is considered a risk factor for obesity. Exposure to perfluorooctanoic acid (PFOA) was found to impair hepatic lipid metabolism, resulting in obesity. In this study, we applied network pharmacology and systematic bioinformatics analysis, such as gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, together with molecular docking, to investigate the targets of fucoidan for treating PFOA-associated obesity through the regulation of endoplasmic reticulum stress (ERS). Our results identified ten targets of fucoidan, such as glucosylceramidase beta (GBA), glutathione-disulfide reductase (GSR), melanocortin 4 receptor (MC4R), matrix metallopeptidase (MMP)2, MMP9, nuclear factor kappa B subunit 1 (NFKB1), RELA Proto-Oncogene, NF-KB Subunit (RELA), nuclear receptor subfamily 1 group I member 2 (NR1I2), proliferation-activated receptor delta (PPARD), and cellular retinoic acid binding protein 2 (CRABP2). GO and KEGG enrichment analyses highlighted their involvement in the pathogenesis of obesity, such as lipid and fat metabolisms. More importantly, the gene cluster is responsible for obesity-associated diseases and disorders, such as insulin resistance (IR), non-alcoholic fatty liver disease, and diabetic cardiomyopathy, via the control of signaling pathways. The findings of this report provide evidence that fucoidan is a potential nutraceutical product against PFOA-associated obesity through the regulation of ERS.

Role of c-miR-21, c-miR-126, Redox Status, and Inflammatory Conditions as Potential Predictors of Vascular Damage in T2DM Patients

The development of type 2 diabetes mellitus (T2DM) vascular complications (VCs) is associated with oxidative stress and chronic inflammation and can result in endothelial dysfunctions. Circulating microRNAs play an important role in epigenetic regulation of the etiology of T2DM. We studied 30 healthy volunteers, 26 T2DM patients with no complications, and 26 T2DM patients with VCs, to look for new biomarkers indicating a risk of developing VCs in T2DM patients. Peripheral blood samples were used to determine redox state, by measuring the endogenous antioxidant defense system (superoxide dismutase, SOD; catalase, CAT; glutathione reductase, GRd; glutathione peroxidase, GPx; and glucose-6-phosphate dehydrogenase, G6DP) and markers of oxidative damage (advanced oxidation protein products, AOPP; lipid peroxidation, LPO). Additionally, inflammatory marker levels (IL-1, IL-6, IL-18, and TNF-α), c-miR-21, and c-miR-126 expression were analyzed. T2DM patients showed the highest oxidative damage with increased GSSG/GSH ratios, LPO, and AOPP levels. In both diabetic groups, we found that diminished SOD activity was accompanied by increased CAT and decreased GRd and G6PD activities. Diabetic patients presented with increased relative expression of c-miR-21 and decreased relative expression of c-miR-126. Overall, c-miR-21, SOD, CAT, and IL-6 had high predictive values for diabetes diagnoses. Finally, our data demonstrated that IL-6 exhibited predictive value for VC development in the studied population. Moreover, c-miR-21 and c-miR-126, along with GPx and AOPP levels, should be considered possible markers for VC development in future studies.

Relationship between Body Composition and Biochemical Parameters with Antioxidant Status in a Healthy Cohort of Postmenopausal Women

An adequate prooxidant–antioxidant balance—which may be influenced by body composition and biochemical status—is essential to maintain human health, especially in circumstances under which the antioxidant defense decreases, such as menopause. The present study aimed to examine the relationship between body composition and biochemical parameters with antioxidant status in a healthy cohort of postmenopausal women. This cross-sectional study was carried out in a cohort of 78 postmenopausal women aged 44–76 years. The body composition profile was assessed through bioelectrical impedance. The determination of the total antioxidant capacity and superoxide dismutase activity was conducted by the colorimetric method, and glutathione peroxidase activity was determined by the enzymatic immunological method. The vitamin D levels were measured by ultra-performance liquid chromatography–tandem mass spectrometry. The mineral status was assessed through flame atomic absorption spectrophotometry. The rest of the biochemical parameters were assessed through an immunoassay. The total antioxidant capacity and antioxidant gap were negatively influenced by body composition (all p ≤ 0.049) and positively related to protein metabolism parameters (all p ≤ 0.048), whereas circulating levels of different micronutrients (all p ≤ 0.048) and enzymes (all p ≤ 0.047) appeared to play an important role in the glutathione peroxidase and superoxide dismutase activities. In conclusion, the menopause-related antioxidant status changes may be influenced by key body composition and biochemical profiles. To confirm this statement, further trials aiming to evaluate the body composition and biochemical intervention-induced changes upon antioxidant defense are needed.

Redox Status of Postmenopausal Women with Single or Multiple Cardiometabolic Diseases Has a Similar Response to Mat Pilates Training

Postmenopausal women have a high prevalence of cardiometabolic diseases and that may associate with higher oxidative stress. Exercise can contribute to the treatment of such diseases, but some modalities, such as Mat Pilates, need to be further studied in terms of their physiological responses. Our aim was to investigate the effects of 12 weeks of Mat Pilates on redox status in postmenopausal women with one or multiple comorbidities of cardiometabolic diseases. Forty-four postmenopausal women were divided into two groups: SINGLE, composed of women with one cardiometabolic disease (n = 20) and MULT, with multimorbidity (n = 24). Mat Pilates training was conducted three times a week for 12 weeks, and each session lasted 50 min. Plasma samples were collected before and after training to analyze the following redox markers: superoxide dismutase, catalase, glutathione peroxidase, total antioxidant capacity due to ferric-reducing antioxidant power (FRAP), reduced glutathione (GSH), uric acid, and carbonyl protein. ANCOVA showed interaction effects in FRAP (p = 0.014). Both groups had reduced levels of catalase (p = 0.240) and GSH (p = 0.309), and increased levels of carbonyl protein (p = 0.053) after intervention. In conclusion, the redox status of postmenopausal women shows no changes mediated by Mat Pilates training between SINGLE and MULT, except for greater reductions of FRAP in SINGLE.

Long-Term High-Fat High-Fructose Diet Induces Type 2 Diabetes in Rats through Oxidative Stress

Long-term consumption of a Western diet is a major cause of type 2 diabetes mellitus (T2DM). However, the effects of diet on pancreatic structure and function remain unclear. Rats fed a high-fat, high-fructose (HFHF) diet were compared with rats fed a normal diet for 3 and 18 months. Plasma biochemical parameters and inflammatory factors were used to reflect metabolic profile and inflammatory status. The rats developed metabolic disorders, and the size of the islets in the pancreas increased after 3 months of HFHF treatment but decreased and became irregular after 18 months. Fasting insulin, C-peptide, proinsulin, and intact proinsulin levels were significantly higher in the HFHF group than those in the age-matched controls. Plasmatic oxidative parameters and nucleic acid oxidation markers (8-oxo-Gsn and 8-oxo-dGsn) became elevated before inflammatory factors, suggesting that the HFHF diet increased the degree of oxidative stress before affecting inflammation. Single-cell RNA sequencing also verified that the transcriptional level of oxidoreductase changed differently in islet subpopulations with aging and long-term HFHF diet. We demonstrated that long-term HFHF diet and aging-associated structural and transcriptomic changes that underlie pancreatic islet functional decay is a possible underlying mechanism of T2DM, and our study could provide new insights to prevent the development of diet-induced T2DM.

New Advances on Pathophysiology of Diabetes Neuropathy and Pain Management: Potential Role of Melatonin and DPP-4 Inhibitors

Pre-diabetes and diabetes are growing threats to the modern world. Diabetes mellitus (DM) is associated with comorbidities such as hypertension (83.40%), obesity (90.49%), and dyslipidemia (93.43%), creating a substantial burden on patients and society. Reductive and oxidative (Redox) stress level imbalance and inflammation play an important role in DM progression. Various therapeutics have been investigated to treat these neuronal complications. Melatonin and dipeptidyl peptidase IV inhibitors (DPP-4i) are known to possess powerful antioxidant and anti-inflammatory properties and have garnered significant attention in the recent years. In this present review article, we have reviewed the recently published reports on the therapeutic efficiency of melatonin and DPP-4i in the treatment of DM. We summarized the efficacy of melatonin and DPP-4i in DM and associated complications of diabetic neuropathy (DNP) and neuropathic pain. Furthermore, we discussed the mechanisms of action and their efficacy in the alleviation of oxidative stress in DM.

Selenium Supplementation Improved Cardiac Functions by Suppressing DNMT2-Mediated GPX1 Promoter DNA Methylation in AGE-Induced Heart Failure

Objective

Advanced glycation end products (AGEs) are featured metabolites associated with diabetic cardiomyopathy which is characterized by heart failure caused by myocyte apoptosis. Selenium was proved cardioprotective. This study was aimed at investigating the therapeutic effects and underlying mechanisms of selenium supplementation on AGE-induced heart failure.

Methods

Rats and primary myocytes were exposed to AGEs. Selenium supplementation was administrated. Cardiac functions and myocyte apoptosis were evaluated. Oxidative stress was assessed by total antioxidant capacity (TAC), reactive oxygen species (ROS) generation, and GPX activity. Expression levels of DNA methyltransferases (DNMTs) and glutathione peroxidase 1 (GPX1) were evaluated. DNA methylation of the GPX1 promoter was analyzed.

Results

AGE exposure elevated intracellular ROS generation, induced myocyte apoptosis, and impaired cardiac functions. AGE exposure increased DNMT1 and DNMT2 expression, leading to the reduction of GPX1 expression and activity in the heart. Selenium supplementation decreased DNMT2 expression, recovered GPX1 expression and activity, and alleviated intracellular ROS generation and myocyte apoptosis, resulting in cardiac function recovery. DNA methylation analysis in primary myocytes indicated that selenium supplementation or DNMT inhibitor AZA treatment reduced DNA methylation of the GPX1 gene promoter. Selenium supplementation and AZA administration showed synergic inhibitory effect on GPX1 gene promoter methylation.

Conclusions

Selenium supplementation showed cardioprotective effects on AGE-induced heart failure by suppressing ROS-mediated myocyte apoptosis. Selenium supplementation suppressed ROS generation by increasing GPX1 expression via inhibiting DNMT2-induced GPX1 gene promoter DNA methylation in myocytes exposed to AGEs.

The molecular link between oxidative stress, insulin resistance, and type 2 diabetes: A target for new therapies against cardiovascular diseases

Type 2 Diabetes Mellitus (T2D) is a chronic disease with a pandemic incidence whose pathogenesis has not yet been clarified. Raising evidence highlighted the role of oxidative stress in inducing insulin resistance, pancreatic beta-cell dysfunction, and leading to cardiovascular disease (CVD). Therefore, understanding the link between oxidative stress, T2D and CVD may help to further understand the pathological processes beyond this association, to personalize the algorithm of the cure, and to find new therapeutic targets. Here, we discussed the role of oxidative stress and the decrease of antioxidant defenses in the pathogenesis of T2D. Furthermore, some aspects of hypoglycemic therapies and their potential role as antioxidant agents were examined, which might be pivotal in preventing CVD in T2D patients.

Dietary Strawberries Improve Biomarkers of Antioxidant Status and Endothelial Function in Adults with Cardiometabolic Risks in a Randomized Controlled Crossover Trial

Strawberries, a popularly consumed berry fruit, are rich in bioactive compounds with antioxidant effects. In this study, we examined the effects of two dietary achievable doses of strawberries on the antioxidant status and biomarkers of endothelial function in adults with features of metabolic syndrome and a confirmed low baseline of fruit and vegetable intake. In a 14-week randomized controlled crossover study, participants were assigned to one of three groups for four weeks separated by a one-week washout period: control powder, one serving (low dose: 13 g strawberry powder/day), or 2.5 servings (high dose: 32 g strawberry powder/day). Blood samples and health data were collected at baseline and at the end of each four-week phase of intervention. Thirty-three participants completed all three phases of the trial. Significant increases were observed in serum antioxidant capacity and superoxide dismutase activity as well as decreases in lipid peroxidation after both low and high dose strawberry phases when compared with the control phase. Significant decreases were also observed in soluble vascular cell adhesion molecule-1 and tumor necrosis factor-α with the high dose strawberry phase. These data confirm that consuming strawberries for four weeks significantly improves antioxidant status, endothelial function, and inflammation in adults with cardiometabolic risks.

Positive effects of selenium supplementation in women with newly diagnosed Hashimoto's thyroiditis in an area with low selenium status

OBJECTIVE

Autoimmune thyroid diseases, including Hashimoto's thyroiditis, are the most common ones among autoimmune diseases. The reported effects of selenium supplementation on the course of Hashimoto's thyroiditis are not consistent. It is therefore important to continue this line of research.

DESIGN

The participants received selenium in the form of sodium selenite(IV) at a dose of 100 µg/day for 6 months.

PATIENTS

Newly diagnosed and previously untreated Hashimoto's thyroiditis with euthyroidism or subclinical hypothyroidism. A total of 36 patients (aged 20 to 52 years) qualified for this study, of whom 29 women were successfully enrolled and completed the intervention.

MEASUREMENTS

Both before and after supplementation the following parameters in serum were tested: anti-thyroid peroxidase antibodies, thyroid function indicators, selenium as well as antioxidant status parameters and other biochemical parameters (lipid profile, glucose). Iodine supply and subjective assessment of physical and psychological health were also monitored.

RESULTS

Selenium supplementation decreased significantly level of anti-thyroid peroxidase antibodies what might have had a stabilizing effect on thyroid function, as values of thyroid parameters were within normal range before and at the end of the study. Mean level of selenium among patients was not different to healthy people in Poland. Median of ioduria was within normal range.

CONCLUSIONS

The study shows a potential way of protective effect of selenium in limiting development of overt hypothyroidism. The increase in the concentrations of Se and SELENOP in the serum of patients verifies successful supplementation and good compliance, but did not affect the antioxidant status parameters measured.

Oxidative Stress: Pathogenetic Role in Diabetes Mellitus and Its Complications and Therapeutic Approaches to Correction

The review presents modern views about the role of oxidative stress reactions in the pathogenesis of types 1 and 2 diabetes mellitus and their complications based on the analysis of experimental and clinical studies. The sources of increased ROS generation in diabetes are specified, including the main pathways of altered glucose metabolism, oxidative damage to pancreatic β-cells, and endothelial dysfunction. The relationship between oxidative stress, carbonyl stress, and inflammation is described. The significance of oxidative stress reactions associated with hyperglycemia is considered in the context of the “metabolic memory” phenomenon. The results of our studies demonstrated significant ethnic and age-related variability of the LPO—antioxidant defense system parameters in patients with diabetes mellitus, which should be considered during complex therapy of the disease. Numerous studies of the effectiveness of antioxidants in diabetes mellitus of both types convincingly proved that antioxidants should be a part of the therapeutic process. Modern therapeutic strategies in the treatment of diabetes mellitus are aimed at developing new methods of personalized antioxidant therapy, including ROS sources targeting combined with new ways of antioxidant delivery.

Evaluation of Salivary Antioxidants and Oxidative Stress Markers in Type 2 Diabetes Mellitus: A Retrospective Cohort Study

BACKGROUND

Diabetes Mellitus (DM) is a progressive metabolic disorder.

OBJECTIVE

The aim of this study was to investigate the relationship between antioxidant and oxidative stress markers in the saliva of patients with type 2 DM and a healthy control group.

METHODS

In this study, 20 patients with diabetes and 20 healthy individuals were evaluated. Salivary antioxidants markers consisted of total antioxidant capacity (TAC), uric acid (UA), peroxidase and catalase. Oxidative stress markers included total oxidant status (TOS), malondealdehyde (MDA) and total thiol (SH). Sialochemical analysis was performed with spectrophotometric assay. All the statistical analyses were conducted using STATA software.

RESULTS

TAC decreased significantly in patients with diabetes. Although salivary UA and peroxidase were lower in patients with diabetes compared to the control group, the difference was not significant. Salivary catalase in patients with diabetes was significantly lower than that in the control group. MDA and TOS exhibited significantly higher levels in type 2 DM. SH levels were slightly higher in DM.

CONCLUSION

According to the results of the present study, there were some changes in the salivary levels of some antioxidants and oxidative stress markers in patients with type 2 DM and could be measured as an indicator of serum changes.

Oxidative stress and neuroinflammation in a rat model of co-morbid obesity and psychogenic stress

BACKGROUND

There is growing recognition for a reciprocal, bidirectional link between anxiety disorders and obesity. Although the mechanisms linking obesity and anxiety remain speculative, this bidirectionality suggests shared pathophysiological processes. Neuroinflammation and oxidative damage are implicated in both pathological anxiety and obesity. This study investigates the relative contribution of comorbid diet-induced obesity and stress-induced anxiety to neuroinflammation and oxidative stress.

METHODS

Thirty-six (36) male Lewis rats were divided into four groups based on diet type and stress exposure: 1) control diet unexposed (CDU) and 2) exposed (CDE), 3) Western-like high-saturated fat diet unexposed (WDU) and 4) exposed (WDE). Neurobehavioral tests were performed to assess anxiety-like behaviors. The catalytic concentrations of glutathione peroxidase and reductase were measured from plasma samples, and neuroinflammatory/oxidative stress biomarkers were measured from brain samples using Western blot. Correlations between behavioral phenotypes and biomarkers were assessed with Pearson's correlation procedures.

RESULTS

We found that WDE rats exhibited markedly increased levels of glial fibrillary acidic protein (185 %), catalase protein (215 %), and glutathione reductase (GSHR) enzymatic activity (418 %) relative to CDU rats. Interestingly, the brain protein levels of glutathione peroxidase (GPx) and catalase were positively associated with body weight and behavioral indices of anxiety.

CONCLUSIONS

Together, our results support a role for neuroinflammation and oxidative stress in heightened emotional reactivity to obesogenic environments and psychogenic stress. Uncovering adaptive responses to obesogenic environments characterized by high access to high-saturated fat/high-sugar diets and toxic stress has the potential to strongly impact how we treat psychiatric disorders in at-risk populations.

Antioxidant and Anti-inflammatory Properties of Yttrium Oxide Nanoparticles: New Insights into Alleviating Diabetes

BACKGROUND

Diabetes mellitus is a metabolic disease that requires immediate attention. Oxidative stress that leads to the generation of reactive oxygen species is a contributing factor to the disease progression. Yttrium oxide nanoparticles (Y₂O₃ NPs) have a profound effect on alleviating oxidative damage.

METHODS

The literature related to Y₂O₃ NPs and oxidative stress has been thoroughly searched using PubMed and Scopus databases and relevant studies from inception until August 2020 were included in this scoping review.

RESULTS

Y₂O₃ NPs altered oxidative stress-related biochemical parameters in different disease models including diabetes.

CONCLUSION

Although Y₂O₃ NPs are a promising antidiabetic agent due to their antioxidant and anti- inflammatory properties, more studies are required to further elucidate the pharmacological and toxicological properties of these nanoparticles.

The effects of pilates and flavanol-rich dark chocolate consumption on the total antioxidant capacity, glycemic control and BMI in diabetic females with neuropathy complications

BACKGROUND

Pilates is a type of exercise recommended to diabetic patients due to its health benefits. Dark chocolate is also well known for its antioxidant properties. The purpose of this study has been to compare the effects of regular Pilates and flavanol-rich dark chocolate consumption on the total antioxidant capacity (TAC), fasting blood glucose (FBG) and BMI in diabetic females with peripheral neuropathy complications.

METHODS

36 diabetic patients enrolled in this single-blinded clinical trial. They were randomly allocated to the control (n = 12), Pilates and dark chocolate intake (n = 12), and Pilates and flavanol-free white chocolate (n = 12) groups. Two Pilates groups consumed 25 gr dark or white chocolate 10 min before each Pilates training session, three times per week, for 8 weeks. The control group consumed 25 gr of the same dark chocolate at a pre-determined time 3 times per week, without any regular exercise. Changes in TAC, BMI and FBG were then measured.

RESULTS

Paired t-test analysis showed significant increases in the TAC status, as compared to the baseline in all groups (P ≤ 0.05). However, BMI and FBG reduction were not significant. Covariance (ANCOVA) analysis also showed a significant difference between groups (p < 0.05). Post-hoc Bonferroni test revealed the group that consumed dark chocolate before training had statistically significant increase in the TAC status compared to other groups.

CONCLUSION

The findings indicated that regular flavanol-rich dark chocolate consumption and Pilates significantly increased the TAC status. While FBG was reduced, it was not statistically significant.

Relationship Between Serum Gamma-Glutamyl Transferase Level and Impaired Fasting Glucose Among Chinese Community-Dwelling Adults: A Follow-Up Observation of 6 Years

Objective: We aimed to investigate the relationship between serum gamma-glutamyl transferase (GGT) and fasting blood glucose (FBG) levels, as well as the cumulative risk of impaired fasting glucose (IFG) regulation in the Chinese adult population after 6 years of follow-up. Methods: A total of 1360 apparently healthy Chinese men and women who completed a community-based health examination survey and did not have IFG in central China in 2010 and 2016 were included in this study. The patients were divided into four groups according to their baseline GGT (in quartiles). The relationship between GGT levels and FBG levels was examined using general linear regression models. The effect of the GGT level on the risk of IFG was analyzed using multivariate logistic regression. The first quartile group of GGT levels was set as the dummy variable in the model, and the odds ratios and 95% confidence intervals of the remaining quartile groups relative to the first quartile group were obtained. Results: After 6 years of follow-up, 16.4% (188/1148) of participants were diagnosed with IFG. The cumulative incidence of IFG in the four groups according to their baseline GGT levels (in quartiles) was 7.7%, 16.1%, 15.8%, and 26.8%, respectively. Based on the Cox multiple regression, the hazard ratio for IFG increased by 28.9% for each unit of increase in the baseline GGT level after adjusting for the confounding factors. The GGT levels of participants in the first quartile were used as the reference group. The relative risks of IFG in the second, third, and fourth quartiles of GGT were 1.70, 1.55, and 2.46, respectively (P = 0.005). Conclusions: GGT was positively associated with the risk of IFG and can be used as an indicator to assess whether a patient may develop prediabetes.

Oxidative Stress Markers in Chronic Kidney Disease with Emphasis on Diabetic Nephropathy

Diabetes prevalence is increasing worldwide, especially through the increase of type 2 diabetes. Diabetic nephropathy occurs in up to 40% of diabetic patients and is the leading cause of end-stage renal disease. Various factors affect the development and progression of diabetic nephropathy. Hyperglycaemia increases free radical production, resulting in oxidative stress, which plays an important role in the pathogenesis of diabetic nephropathy. Free radicals have a short half-life and are difficult to measure. In contrast, oxidation products, including lipid peroxidation, protein oxidation, and nucleic acid oxidation, have longer lifetimes and are used to evaluate oxidative stress. In recent years, different oxidative stress biomarkers associated with diabetic nephropathy have been found. This review summarises current evidence of oxidative stress biomarkers in patients with diabetic nephropathy. Although some of them are promising, they cannot replace currently used clinical biomarkers (eGFR, proteinuria) in the development and progression of diabetic nephropathy.

Association between High On-Aspirin Platelet Reactivity and Reduced Superoxide Dismutase Activity in Patients Affected by Type 2 Diabetes Mellitus or Primary Hypercholesterolemia

Platelet hyperactivation is involved in the established prothrombotic condition of metabolic diseases such as Type 2 Diabetes Mellitus (T2DM) and familial hypercholesterolemia (HC), justifying the therapy with aspirin, a suppressor of thromboxane synthesis through the irreversible inhibition of cyclooxygenase-1 (COX-1), to prevent cardiovascular diseases. However, some patients on aspirin show a higher than expected platelet reactivity due, at least in part, to a pro-oxidant milieu. The aim of this study was to investigate platelet reactivity in T2DM (n = 103) or HC (n = 61) patients (aspirin, 100 mg/day) and its correlation with biomarkers of redox function including the superoxide anion scavenger superoxide dismutase (SOD) and the in vivo marker of oxidative stress urinary 8-iso-prostaglandin F_2α. As results, in T2DM and HC subjects the prevalence of high on-aspirin platelet reactivity was comparable when both non-COX-1-dependent and COX-1-dependent assays were performed, and platelet reactivity is associated with a lower SOD activity that in a stepwise linear regression appears as the only predictor of platelet reactivity. To conclude, in T2DM and HC, similarly, the impairment of redox equilibrium associated with a decrease of SOD activity could contribute to a suboptimal response to aspirin.

Apolipoprotein A-I Supports MSCs Survival under Stress Conditions

Clinical trials have shown the safety of mesenchymal stem/stromal cells (MSCs) transplantation, but the effectiveness of these treatments is limited. Since, transplanted MSCs will undergo metabolic disturbances in the bloodstream, we investigated the influence of blood plasmas of type 2 diabetes (T2D) patients on MSCs viability and examined whether apolipoprotein A-I (apoA-I) could protect cells from stressful conditions of serum deprivation (SD), hypoxia, and elevated concentrations of reactive oxygen species (ROS). ApoA-I exhibits anti-inflammatory, immune activities, improves glycemic control, and is suitable for T2D patients but its influence on MSCs remains unknown. For the first time we have shown that apoA-I decreases intracellular ROS and supports proliferative rate of MSCs, thereby increasing cell count in oxidation conditions. ApoA-I did not influence cell cycle when MSCs were predominantly in the G0/G1 phases under conditions of SD/hypoxia, activated proliferation rapidly, and reduced apoptosis during MSCs transition to the oxygenation or oxidation conditions. Finally, it was found that the blood plasma of T2D individuals had a cytotoxic effect on MSCs in 39% of cases and had a wide variability of antioxidant properties. ApoA-I protects cells under all adverse conditions and can increase the efficiency of MSCs transplantation in T2D patients.

MnSOD Val16Ala gene polymorphism is associated with REDOX biomarkers in the elderly of primary health care in the city of Porto Alegre

Studies suggest that redox imbalance may be closely associated with pathological aging, contributing effectively to the genesis of several chronic diseases. One of the major defence enzymes against oxidation is Manganese-dependent superoxide dismutase (MnSOD) that acts within the mitochondria. The gene encoding this enzyme is polymorphic and Val16Ala variant is one of its most investigated polymorphisms regarding aging and oxidative stress. This study aimed to verify the occurrence of the MnSOD Val16Ala gene polymorphism association with markers of REDOX metabolism in the elderly of primary health care. A cross-sectional study was performed. The sample consisted of 270 elderly individuals from Family Health Strategy in the city of Porto Alegre, Rio Grande do Sul, Brazil (EMISUS). The following variables were investigated in all subjects: sociodemographic: gender, age, marital status, schooling and income; Anthropometric: weight, height, body mass index (BMI); REDOX markers: advanced oxidation protein products (AOPP), ischemia-modified albumin (IMA), nitric oxide metabolites (NOx), ferric reducing ability of plasma (FRAP) and malondialdehyde (MDA), MnSOD Val16Ala gene polymorphism. Val16Ala gene polymorphism was evaluated by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Statistically significant associations were observed in the elderly with AA genotype compared to those with VV genotype, concerning AOPP (p = 0.023) and FRAP (p = 0.027) quartile frequencies, respectively. No statistically significant differences were observed between MnSOD genotypes with MDA, NOx and IMA oxidative markers. Val16Ala gene polymorphism is associated with AOPP and FRAP quartiles frequencies in the elderly of primary health care.

Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity in patients with diabetes mellitus type 2 infected with Epstein-Barr virus

Oxidative stress is suggested to be the crucial factor in diabetes mellitus type 2 (DM2) pathogenesis and in the development of diabetic complications. Patients with DM2 may be more susceptible to infections due to hyperglycaemia-induced virulence of various microorganisms. Several studies pointed that Epstein-Barr virus (EBV) infection is associated with reactive oxygen species (ROS) production and/or activation of signalling pathways connected with ROS. The present study analyzed serum activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD) in DM2 patients with and without EBV infection. Blood and saliva were collected from 120 patients with DM2. EBV DNA was detected in the saliva using nested-PCR technique. Spectrophotometric methods were implemented to determine serum GPx and SOD activity with the use of diagnostic kits produced by Randox Laboratories. GPx and SOD activity was decreased in diabetic patients, with the lowest values in DM2 EBV-positive patients. There was correlation between GPx and SOD activity-with increased value of GPx, SOD activity was also rised. In patients with DM2 history longer than 10 years as well as in DM2 patients with obesity, antioxidant enzymes activity was decreased. Determination of examined parameters may be useful in diabetic patients with EBV infection and could be important prognostic factor.

Antioxidant and Anti-Inflammatory Properties of Melatonin in Patients with Type 2 Diabetes Mellitus with Periodontal Disease Under Non-Surgical Periodontal Therapy: A Double-Blind, Placebo-Controlled Trial

BACKGROUND AND AIM

The imbalance between pro-oxidant and antioxidant systems often leads to further oxidative damage in the pathogenesis of both diabetes and periodontal disease. This study aimed to investigate the antioxidant and anti-inflammatory properties of melatonin in type 2 diabetes mellitus (T2DM) patients with periodontal disease (PD) under non-surgical periodontal therapy (NSPT).

MATERIALS AND METHODS

In this double-blind clinical trial study, 50 T2DM patients with PD were randomly allocated to intervention and control groups and received 250 mg/day (2 tablets) either melatonin or placebo 1 h before bedtime for 8 weeks. The NSPT was performed for all patients in both groups at the beginning of the study. The serum levels of interleukin-1b (IL-1b), malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were measured pre- and post-intervention.

RESULTS

Supplementation with melatonin in adjunct to NSPT significantly increased the serum levels of TAC, SOD, CAT, and GPx in the intervention group (P = 0.02, 0.008, 0.004 and 0.004, respectively). The mean changes of SOD, CAT, and GPx were significantly (P = 0.02, 0.04 and 0.04, respectively) greater in the intervention group compared with the control group. Also, after adjusting for confounding factors, the results did not change in terms of significance (P < 0.05). After the intervention, serum levels of MDA and IL-1b were significantly reduced in the intervention group (P < 0.001 and P = 0.008, respectively). The intervention group exhibited lower mean changes of MDA compared with the control group, and these changes were statistically significant (P = 0.008). In addition, after adjusting for confounding factors, the results did not change in terms of significance.

CONCLUSION

The adjunctive effects of melatonin and NSPT may improve inflammatory and antioxidant parameters in T2DM patients with PD.

Resveratrol Reduces Lipid Accumulation through Upregulating the Expression of MicroRNAs Regulating Fatty Acid Bet Oxidation in Liver Cells: Evidence from In-vivo and In-vitro Studies

MicroRNAs have been shown to regulate lipogenesis in liver. The aim of the present study was to investigate whether the effects of resveratrol (RSV) on lipogenesis are associated with the changes in the expression of two miRNAs (miR-107 and miR-10b) that regulate lipogenic pathways. 30 wild type C57BL/6j male mice were randomly fed three diets: a standard chow diet (ND), a high fat diet (HFD, 60% fat) and the high fat diet supplemented with 0.4% RSV (HFD-RSV) for 16 weeks. HepG2 cells were treated with high glucose (33 mM) and RSV (20 µM) for 24 h. The expression of the genes and miRNAs were measured by real-time PCR. Triglyceride level was increased in the liver of mice and HepG2 cells. In both animal and In-vitro experiments, triglyceride level was significantly decreased in groups treated with RSV. The expression of the miR-107 and miR-10b was significantly upregulated in the liver of HFD mice, whereas HFD-RSV group demonstrated a significant lower expression of both miRNAs compared to HFD group. In addition, RSV treatment significantly upregulated the expression of CPT-1a and PPARα genes in the liver of HFD mice. Moreover, treatment with RSV could reduce the expression of miR-107 and miR-10b and increase the expression of CPT-1a and PPARα in HG-treated HepG2 cells. These evidence, as a whole, suggest that RSV could exert its anti-lipogenic effect partially through alterations in the expression of miR-107 and miR-10b in liver cells.

Selenium Levels in Community Dwellers with Type 2 Diabetes Mellitus

Selenium (Se) is an essential micronutrient required by the human body and exerts biological functions through selenoproteins. The relationship between Se and diabetes remains ambiguous. This study aimed at, through measurements of serum selenoprotein P (SelP), glutathione peroxidase (GPx3), and Se content in serum and hair, evaluating Se levels in community dwellers with type 2 diabetes mellitus (T2DM). A total of 336 subjects, including 176 T2DM patients (65.5 ± 8.7 years old) and 160 healthy residents (63.7 ± 9.8 years old, as controls), were recruited in this cross-sectional community-based study performed in Suzhou. Samples of fasting venous blood and hair were collected for measurements of Se levels, glycometabolism, and biochemistry parameters. We found that the serum Se level and SelP concentration in T2DM patients were substantially higher than those in healthy residents (p < 0.05). There was no significant difference in GPx3 activity and hair Se level between the two groups of subjects (p > 0.05). Serum Se was positively correlated with both GPx3 and hair Se in T2DM patients (r = 0.167 and 0.164, respectively, p < 0.05) and negatively correlated with SelP in healthy controls (r = - 0.293, p < 0.05). In conclusion, this study showed significantly higher levels of serum Se and SelP in community dwellers with T2DM than in matched healthy residents.

Poor Glycaemic Control Is Associated with Increased Lipid Peroxidation and Glutathione Peroxidase Activity in Type 2 Diabetes Patients

Glycaemic control is the main focus of managing diabetes and its complications. Hyperglycaemia induces oxidative stress favouring cellular damage and subsequent diabetic complications. The present study was conducted to compare the plasma total antioxidant capacity (TAC) and individual antioxidant marker antioxidant status of type 2 diabetics (T2D) with good ((+) GC) and poor ((-) GC) glycaemic control with prediabetic (PDM) and normoglycaemic (NG) individuals. T2D (n = 147), PDM (n = 47), and NGC (n = 106) were recruited as subjects. T2D and PDM had lower plasma TAG than NG subjects. T2D and PDM had significantly higher GPx activity and plasma MDA concentrations than NG. PDM showed the highest SOD activity. T2D (-) GC showed significantly elevated GPx activity and higher MDA level and significantly lower SOD activity among all study groups. Lower plasma TAC and higher plasma MDA indicate the presence of oxidative stress in T2D and PDM. Elevated GPx activity in T2D, PDM, and particularly in T2D (-) GC suggests a compensatory response to counteract excess lipid peroxidation in the hyperglycaemic state. Decline in SOD activity advocates the presence of glycation and excess lipid peroxidation in T2D.

The Impact of Glycemic Status and Metformin Administration on Red Blood Cell Indices and Oxidative Stress in Type 2 Diabetic Patients

BACKGROUND

Most guidelines all over the world recommended metformin as the first-line treatment for in type 2 diabetic patients. Therefore, the present study was suggested to assess the outcome of metformin administration and glycemic status on alterations in red blood cell (RBCs) indices as well as the oxidative stress in type 2 diabetic patients.

METHODS

Between December 2016 and October of 2017, a total of 158 eligible individuals were classified as 50 healthy subjects and 108 diabetic patients who were subdivided into six groups according to the type of anti-diabetic treatments.

RESULTS

Overall, the results elucidated that hemoglobin concentration was markedly diminished, while red cell distribution width (RDW) value was significantly (P < 0.001) elevated in all diabetic groups as compared to control. Moreover, in all diabetic groups, malondialdehyde (MDA) concentration was elevated noticeably (P < 0.001), while reduced glutathione (GSH) revealed a lower concentration (P < 0.001) than that of control.

CONCLUSION

The present study exhibited the amelioration effect of metformin administration on oxidative stress and glycemic status which reflected on some RBCs indices. However, hemoglobin concentration showed a noticeable diminution in all metformin-treated groups in spite of the improvement in glycemic and oxidative stress status which indicated that the metformin-induced anemia is independently from diabetic complications.

Higher oxidative balance score is associated with better glycemic control among Iranian adults with type-2 diabetes

The oxidative balance score (OBS) is a measure of combined pro- and anti-oxidant exposure status, with a higher OBS representing a predominance of anti- over pro-oxidant exposures. We aimed to examine the association of OBS and glycemic control among Iranian adults with type-2 diabetes. This cross-sectional study was conducted among 476 adults with type-2 diabetes (mean age 56.2 y; 66.6% female). Fasting glycosylated hemoglobin (HbA_1c) and serum glucose (FSG) levels were measured as markers of glycemic control. The OBS was calculated by combining information from a total of 18 a priori selected pro- and anti-oxidant components. These components were comprised of the following four categories: dietary anti-oxidants (i.e., dietary intakes of selenium, fiber, retinol, α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene, vitamin D, vitamin E, folate, and vitamin C); dietary pro-oxidants (i.e., dietary intakes of iron, saturated fatty acid, and poly-unsaturated fatty acid); non-dietary anti-oxidants (i.e., physical activity); and non-dietary pro-oxidants (i.e., smoking and obesity). After adjusting for several potential confounders in the analysis of covariance models, multivariable adjusted means of HbA_1c and FSG of subjects in the highest tertile of OBS were significantly lower than those in the lowest tertile (for HbA_1c: mean difference -0.73%; and for FSG: mean difference -10.2 mg/dL; both P < 0.050). The findings suggest that a higher OBS, indicating a predominance of anti- over pro-oxidant exposures, is associated with a better glycemic control among Iranian adults with type-2 diabetes. However, future prospective studies of adequate methodological quality are warranted to confirm these findings.

Oxidative stress markers in cognitively intact patients with diabetic neuropathy

Various forms of vascular injury are frequently associated with type-2 diabetes mellitus (DM2). Macro-angiopathy has alarming signs and symptoms such as those seen with stroke or heart attack, however the presentation of small vessel disease is generally more subtle and therefore usually unnoticed for a long period of time. While it may affect any organ, complications involving the nervous system such as diabetic poly-neuropathy (DPN) are especially debilitating, and it may also be a risk factor for other brain disorders such as dementia. The underlying mechanisms are likely to be multi-faceted, but piling evidence indicates oxidative stress as one of the crucial factors. Here we evaluate the oxidative profile of patients with DM2. The total anti-oxidant capacity appears to be reduced in DM2 with or without complications. Of the specific bio-markers studied, the levels of tissue-damage indicator malon-dialdehyde (MDA) were significantly lower in the DM2 + DPN population only. These results suggest that diabetic patients present with wavering oxidative status, and the low MDA concentrations in patients with complications such as DPN may represent either an exhausted anti-oxidative defense system or a response to anti-inflammatory medications. The findings may also support the use of anti-oxidants such as vitamins A and E.

Circulating Oxidative Stress Biomarkers in Clinical Studies on Type 2 Diabetes and Its Complications

Type 2 diabetes (T2DM) and its complications constitute a major worldwide public health problem, with high rates of morbidity and mortality. Biomarkers for predicting the occurrence and development of the disease may therefore offer benefits in terms of early diagnosis and intervention. This review provides an overview of human studies on circulating biomarkers of oxidative stress and antioxidant defence systems and discusses their usefulness from a clinical perspective. Most case-control studies documented an increase in biomarkers of oxidative lipid, protein, and nucleic acid damage in patients with prediabetes and in those with a diagnosis of T2DM compared to controls, and similar findings were reported in T2DM with micro- and macrovascular complications compared to those without. The inconsistence of the results regarding antioxidant defence systems renders difficulty to draw a general conclusion. The clinical relevance of biomarkers of oxidative lipid and protein damage for T2DM progression is uncertain, but prospective studies suggest that markers of oxidative nucleic acid damage such as 8-hydroxy-2'-deoxyguanosine and 8-hydroxyguanosine are promising for predicting macrovascular complications of T2DM. Emerging evidence also points out the relationship between serum PON1 and serum HO1 in T2DM and its complications. Overall, enhanced oxidative damage represents an underlying mechanism of glucose toxicity in T2DM and its related micro- and macrovascular complications suggesting that it may be considered as a potential additional target for pharmacotherapy. Therefore, further studies are needed to understand whether targeting oxidative stress may yield clinical benefits. In this view, the measurement of oxidative stress biomarkers in clinical trials deserves to be considered as an additional tool to currently used parameters to facilitate a more individualized treatment of T2DM in terms of drug choice and patient selection.

Association between Glycated Hemoglobin with the Levels of Serum Proinflammatory Cytokines and Antioxidants in Patients with Type 2 Diabetes Mellitus in Universitas Sumatera Utara Hospital

BACKGROUND:

Hyperglycemia condition in diabetes mellitus (DM) influences proinflammatory cytokine levels and disrupts antioxidant balances. Glycated Hemoglobin is used as a biomarker of glycemic control in DM.

AIM:

This study aimed to analyse the association between glycated Hemoglobin with the levels of serum proinflammatory cytokines (interleukin (IL)-6) and antioxidants (glutathione peroxidase (GPx) and glutathione (GSH)) in type 2 diabetes mellitus (T2DM) patients in Universitas Sumatera Utara (USU) Hospital.

METHODS:

A total of eighty-nine T2DM patients were recruited at USU Hospital. Glycated Hemoglobin levels were measured using routine laboratory tests at USU Hospital. The IL-6, GPx, and GSH levels were measured using enzyme-linked immunosorbent (ELISA) method. The statistical significance was determined using the Kruskal Wallis test, followed by Mann-Whitney test (p < 0.05).

RESULTS:

The mean of glycated hemoglobin (%), IL-6 (pg/ml), GPx (ng/ml), and GSH (ng/ml) levels in T2DM patients were 8.96 ± 2.28, 59.27 ± 16.04, 32.13 ± 12.10, and 7.42 ± 3.50, respectively. Regarding the glycated Hemoglobin levels, 28.09% of patients had controlled diabetes, 24.72% of patients had poorly controlled diabetes, and 47.19% of patients had uncontrolled diabetes. The IL-6 levels of the three study groups based on glycated Hemoglobin levels were related significantly (p < 0.05), but there was no statistically significant difference observed between the GPx and GSH levels (p > 0.05).

CONCLUSION:

The present study suggests that the glycated Hemoglobin was associated with the levels of serum IL-6 levels but not GPx and GSH levels in T2DM patients in USU Hospital.

The effects of resveratrol on markers of oxidative stress in patients with type 2 diabetes: a randomized, double-blind, placebo-controlled clinical trial

AIMS

Oxidative stress plays a pivotal role in the pathogenesis of type 2 diabetes (T2D). In vitro and animal studies have shown that resveratrol exerts an antioxidant effect, but clinical trials addressing this effect in patients with T2D are limited. The aim of this study was to determine whether resveratrol supplementation affects oxidative stress markers in a randomized, placebo-controlled, double-blind clinical trial.

METHODS

A total of 48 patients with T2D randomly were assigned to receive 800 mg/day resveratrol or placebo for 2 months. Plasma total antioxidant capacity, malondialdehyde concentration, protein carbonyl and total thiol contents, intracellular superoxide anion (O₂^-·) and hydrogen peroxide (H₂O₂) in PBMCs, the expression of genes involved in oxidative stress responses (Nrf2, SOD, Cat, HO-1, RAGE, NOS) in PBMCs, and metabolic and anthropometric parameters were measured at the baseline and at the trial end.

RESULTS

Compared with the placebo group, resveratrol reduced plasma protein carbonyl content and PBMCs O₂^-· level and significantly increased plasma total antioxidant capacity and total thiol content. Furthermore, the expression of Nrf2 and SOD was significantly increased after resveratrol consumption. Resveratrol had no significant effects on the metabolic and anthropometric parameters except for a significant reduction in weight, BMI, and blood pressure levels. Resveratrol was well tolerated, and no serious adverse event was occurred.

CONCLUSIONS

Our study demonstrated that 8 weeks of supplementation with 800 mg/day resveratrol has an antioxidant effect in the blood and PBMCs of patients with T2D. Clinical Trial Registry number and website IRCT registration number: IRCT2015072523336N1 and http://en.search.irct.ir/view/24752 .

Selected serum oxidative stress biomarkers in dogs with non-food-induced and food-induced atopic dermatitis

BACKGROUND

Oxidative stress (OS) has been shown to be involved in the pathogenesis of human and canine atopic dermatitis (AD) through several distinct mechanisms. Selected serum biomarkers of OS (sbOS) have been validated in normal dogs and studied in several canine diseases. To the best of the authors' knowledge, the sbOS evaluated in this study have not previously been described in canine AD.

HYPOTHESIS/OBJECTIVES

The aims of the study were to evaluate a panel of sbOS in dogs with food-induced (FIAD) and non-food-induced (NFIAD) AD: cupric reducing antioxidant capacity (CUPRAC), ferrous oxidation-xylenol orange (FOX), ferric reducing ability of the plasma (FRAP), paraoxonase-1 (PON1), trolox equivalent antioxidant capacity (TEAC) and serum total thiol (THIOL). The aim was to compare these metabolites with those in healthy control dogs, and to correlate sbOS with validated pruritus and CADESI-04 severity scales in dogs with AD.

ANIMALS

Forty six healthy, nine NFIAD and three FIAD client-owned dogs were included.

METHODS

The study was designed as a cohort study.

RESULTS

There were significant differences in atopic dogs when compared to healthy dogs for all of the sbOS analysed.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings suggest that OS could play a role in the pathogenesis of canine NFIAD and FIAD. In addition, the evaluation of sbOS could be useful for precision medicine to help to detect atopic dogs that might benefit from antioxidant-targeted therapies.

The postpartum effect of maternal diabetes on the circulating levels of sirtuins and superoxide dismutase

Gestational diabetes mellitus (GDM) is a glucose intolerance disorder which occurs during pregnancy as a result of insulin insensitivity; it usually disappears after delivery. However, some women with GDM can develop type 2 diabetes (T2D) after delivery, and the mechanisms by which this occurs remain unknown. This study compared the levels of sirtuins (NAD‐dependent deacetylases) and antioxidative enzymes in postpartum women with previous GDM (pGDM) or T2D and in postpartum women with a previous healthy pregnancy (controls). Women with pGDM showed upregulated levels of sirtuin 1 (SIRT1) mRNA and protein, with reduced expression levels of sirtuin 3 (SIRT3) and superoxide dismutase 2 (SOD2), relative to the controls. Women with T2D similarly showed a lower level of SIRT3 mRNA than the controls. Lipid peroxidation (malondialdehyde) was higher in women with pGDM than in the controls. These data show that in women with pGDM, the reduced level of SIRT3 may play a role in the reduced SOD2 level, possibly leading to oxidative stress, which, in turn, upregulates the level of SIRT1. These results might confer the risk of future diabetes development in women with pGDM, as a similar reduction in SIRT3 was found in women with T2D.

Can Antioxidative Status Be Involved in Type 1 Diabetes?

Background

Type 1 diabetes mellitus (T1DM) is an autoimmune disease with beta-cell destruction, resulting in insulin deficiency. It is now clear that environmental factors also play a role in disease development. The prevalence of type 1 diabetes in children and young people in Portugal is 0.16% between 0 and 19 years of age. The main cause of death in T1DM is cardiovascular disease, and early endothelial dysfunction is its pathophysiologycal precursor. Hyperglycemia is associated with increased production of free radicals and increased oxidative stress. The aim of this study was to analyze the antioxidant status in a pediatric portuguese diabetic population.

Methods

The study was conducted to characterize and compare the antioxidant status in children aged 2 - 10 years old, with type 1 diabetes and healthy children. Plasmatic profile of total phenolic content (TPC), ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) in children with diabetes and controls, pre-pubescent, and with BMI < 85th centile were evaluated.

Results

FRAP values were significantly lower in diabetic children compared with healthy controls (P < 0.001). There was not any statistical significant difference in the TPC and the TEAC determinations.

Conclusions

Young Portuguese diabetic children have a lower antioxidant status than healthy children.

Measurement and Clinical Significance of Biomarkers of Oxidative Stress in Humans

Oxidative stress is the result of the imbalance between reactive oxygen species (ROS) formation and enzymatic and nonenzymatic antioxidants. Biomarkers of oxidative stress are relevant in the evaluation of the disease status and of the health-enhancing effects of antioxidants. We aim to discuss the major methodological bias of methods used for the evaluation of oxidative stress in humans. There is a lack of consensus concerning the validation, standardization, and reproducibility of methods for the measurement of the following: (1) ROS in leukocytes and platelets by flow cytometry, (2) markers based on ROS-induced modifications of lipids, DNA, and proteins, (3) enzymatic players of redox status, and (4) total antioxidant capacity of human body fluids. It has been suggested that the bias of each method could be overcome by using indexes of oxidative stress that include more than one marker. However, the choice of the markers considered in the global index should be dictated by the aim of the study and its design, as well as by the clinical relevance in the selected subjects. In conclusion, the clinical significance of biomarkers of oxidative stress in humans must come from a critical analysis of the markers that should give an overall index of redox status in particular conditions.