Oxidative stress and diabetes: what can we learn about insulin resistance from antioxidant mutant mouse models?

The Role of Overexpressed Apolipoprotein AV in Insulin-Resistant Hepatocytes

In this paper, we sought to explore the relationship between apolipoprotein AV (APOAV) overexpression and insulin resistance in hepatocytes. The insulin-resistant HepG2 cell model was constructed, and then, APOAV-overexpressed HepG2 cells (B-M) were induced by infecting with a recombinant adenovirus vector. Microarray data were developed from B-M samples compared with negative controls (A-con), and the microarray data were analyzed by bioinformatic methods. APOAV-overexpression induced 313 upregulated genes and 563 downregulated ones in B-M sample. The differentially expressed genes (DEGs) were significantly classified in fat digestion and absorption pathway. Protein-protein interaction network was constructed, and AGTR1 (angiotensin II receptor type 1) and P2RY2 (purinergic receptor P2Y, G-protein coupled 2) were found to be the significant nodes closely related with G-protein related signaling. Additionally, overexpression of APOAV could change the expression of Glut4 and release the insulin resistance of hepatic cells. Thus, APOAV overexpression may prevent the insulin resistance in liver cells by mediating the genes such as AGTR1 and P2RY2.

Serum albumin cysteine trioxidation is a potential oxidative stress biomarker of type 2 diabetes mellitus

Metabolic disorders in T2DM generate multiple sources of free radicals and oxidative stress that accelerate nonenzymatic degenerative protein modifications (DPMs) such as protein oxidation, disrupt redox signaling and physiological function, and remain a major risk factor for clinical diabetic vascular complications. In order to identify potential oxidative biomarkers in the blood plasma of patients with T2DM, we used LC-MS/MS-based proteomics to profile plasma samples from patients with T2DM and healthy controls. The results showed that human serum albumin (HSA) is damaged by irreversible cysteine trioxidation, which can be a potential oxidative stress biomarker for the early diagnosis of T2DM. The quantitative detection of site-specific thiol trioxidation is technically challenging; thus, we developed a sensitive and selective LC-MS/MS workflow that has been used to discover and quantify three unique thiol-trioxidized HSA peptides, ALVLIAFAQYLQQC_(SO3H)PFEDHVK (m/z 1241.13), YIC_(SO3H)ENQDSISSK (m/z 717.80) and RPC_(SO3H)FSALEVDETYVPK (m/z 951.45), in 16 individual samples of healthy controls (n = 8) and individuals with diabetes (n = 8). Targeted quantitative analysis using multiple reaction monitoring mass spectrometry revealed impairment of the peptides with m/z 1241.13, m/z 717.80 and m/z 951.45, with significance (P < 0.02, P < 0.002 and P < 0.03), in individuals with diabetes. The results demonstrated that a set of three HSA thiol-trioxidized peptides, which are irreversibly oxidatively damaged in HSA in the plasma of patients with T2DM, can be important indicators and potential biomarkers of oxidative stress in T2DM.

A Longitudinal Study of the Antioxidant Barrier and Oxidative Stress in Morbidly Obese Patients after Bariatric Surgery. Does the Metabolic Syndrome Affect the Redox Homeostasis of Obese People?

This is the first study to evaluate both the antioxidant barrier, glutathione metabolism, and oxidative damage to proteins and lipids in morbidly obese patients undergoing bariatric treatment. The study included 65 patients with class 3 obesity divided into two subgroups: morbidly obese patients without metabolic syndrome (OB) and obese patients with metabolic syndrome (OB + MS). Blood samples were collected before surgery as well as one, three, six, and twelve months after the bariatric treatment. Superoxide dismutase and reduced glutathione (GSH) were significantly decreased, whereas glutathione reductase and uric acid were enhanced in morbidly obese patients before bariatric surgery as compared to lean control. Moreover, in the OB group, we observed the increase of superoxide dismutase (SOD) and the decrease of uric acid (UA) after the bariatric treatment; however, these changes were not observed in the OB + MS group. The oxidative damage to proteins (advanced glycation end products, AGE; advanced oxidation protein products, AOPP) and lipids (8-isoprostanes, 8-isop; 4-hydroxynoneal) was higher in OB as well as OB + MS patients. We noticed that AGE and AOPP levels diminished after the bariatric treatment, whereas redox status (ratio of GSH to oxidized glutathione) was still reduced in the OB + MS group. Summarizing, morbid obesity is associated with disturbances in the antioxidant barrier and enhanced oxidative damage to proteins and lipids. Although bariatric surgery improves redox homeostasis in obese patients, those with metabolic syndrome show a continuous decrease in the antioxidant status. In patients undergoing bariatric treatment, antioxidant supplementation may be considered.

The Effects of Endoplasmic-Reticulum-Resident Selenoproteins in a Nonalcoholic Fatty Liver Disease Pig Model Induced by a High-Fat Diet

The present study aimed to investigate the intervention of selenium in the oxidative stress and apoptosis of pig livers, which were induced by a high-fat diet, and the effects of four endoplasmic reticulum (ER)-resident selenoproteins in the process. A 2 × 4 design trial was conducted that included two dietary fat levels (BD = basal diet and HFD = high-fat diet) and four dietary Se supplementation levels (0, 0.3, 1.0, and 3.0 mg/kg of the diet, in the form of sodium selenite (Na₂SeO₃)). Our results indicated that the HFD significantly increased the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum, as well as the degree of steatosis, the content of malondialdehyde (MDA), the apoptotic rate, and the level of mRNA caspase-3 in the liver compared to their BD counterparts (p < 0.05). Moreover, these parameters in the HFD groups were more significantly reduced (p < 0.05) for a Se concentration of 1.0 mg/kg than for the other concentrations. Further, for both the BD and HFD, the groups supplemented with 1.0 mg/kg Se showed the highest mRNA level of selenoprotein S. In conclusion, the consumption of an HFD can induce oxidative damage and apoptosis in the liver. This shows that the supplementation of Se at 1.0 mg/kg may be the optimum concentration against damage induced by HFD, and Sels may play a key role in this process.

The effect of intramuscular megadose of vitamin D injections on E-selectin, CRP and biochemical parameters in vitamin D-deficient patients with type-2 diabetes mellitus: A randomized controlled trial

BACKGROUND AND AIMS

Inflammatory processes has been shown to be associated with the development of type 2 diabetes mellitus (T2DM) in which vitamin D supplementation might exert beneficial outcomes. We examined the effects of vitamin D supplement on inflammatory and cell adhesion molecule in patients with T2DM.

METHODS

This study consisted of 50 patients with T2DM who had vitamin D deficiency. Participants were randomized into two groups of 25 in which the intervention group received two intramuscular injections of a 200000-IU vitamin D supplement, one at week 0 and another at week 4. The concentrations of fasting blood glucose (FBG), lipid profiles, liver enzymes, E-selectin, C-reactive protein (CRP), calcium, phosphorus, serum 25-hydroxyvitamin D [25(OH)D] and anthropometric indices were obtained before and after 8 weeks.

RESULTS

Vitamin D resulted in significant reductions in CRP(P = 0.01) and gamma glutamyl transferase (GGT) levels(P = 0.03) and significant increases in 25(OH)D concentrations(P = 0.01) in the intervention group compared with the control. Within-group comparisons showed that FBG decreased significantly in the intervention group(P = 0.04). No significant changes were observed regarding within- and between-group comparisons of the other markers.

CONCLUSION

Vitamin D had beneficial effects on the levels of CRP, serum 25(OH)D and GGT among vitamin D deficient patients with T2DM. (http://www.irct.ir: IRCT2017100336539N1).

Strenuous Acute Exercise Induces Slow and Fast Twitch-Dependent NADPH Oxidase Expression in Rat Skeletal Muscle

The enzymatic complex Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase (NOx) may be the principal source of reactive oxygen species (ROS). The NOX2 and NOX4 isoforms are tissue-dependent and are differentially expressed in slow-twitch fibers (type I fibers) and fast-twitch fibers (type II fibers) of skeletal muscle, making them different markers of ROS metabolism induced by physical exercise. The aim of this study was to investigate NOx signaling, as a non-adaptive and non-cumulative response, in the predominant fiber types of rat skeletal muscles 24 h after one strenuous treadmill exercise session. The levels of mRNA, reduced glycogen, thiol content, NOx, superoxide dismutase, catalase, glutathione peroxidase activity, and PPARGC1α and SLC2A4 gene expression were measured in the white gastrocnemius (WG) portion, the red gastrocnemius (RG) portion, and the soleus muscle (SOL). NOx activity showed higher values in the SOL muscle compared to the RG and WG portions. The same was true of the NOX2 and NOX4 mRNA levels, antioxidant enzymatic activities, glycogen content. Twenty-four hours after the strenuous exercise session, NOx expression increased in slow-twitch oxidative fibers. The acute strenuous exercise condition showed an attenuation of oxidative stress and an upregulation of antioxidant activity through PPARGC1α gene activity, antioxidant defense adaptations, and differential gene expression according to the predominant fiber type. The most prominent location of detoxification (indicated by NOX4 activation) in the slow-twitch oxidative SOL muscle was the mitochondria, while the fast-twitch oxidative RG portion showed a more cytosolic location. Glycolytic metabolism in the WG portion suggested possible NOX2/NOX4 non-regulation, indicating other possible ROS regulation pathways.

A Review on Free Radicals and Antioxidants

Free radicals are generated in our body by several systems. A balance among free radicals and antioxidants is an important matter for appropriate physiological function. If free radicals become greater than the ability of the body to control them, a case known as oxidative stress appears, as a result of that, a number of human diseases spread in the body. Antioxidants can contribute to facingthis oxidative stress. The present review provides a brief overview of free radicals, oxidative stress, some natural antioxidants and the relationship between them.

Impact of Alpha-Lipoic Acid Chronic Discontinuous Treatment in Cardiometabolic Disorders and Oxidative Stress Induced by Fructose Intake in Rats

Insulin resistance (IR) and cardiometabolic disorders are the main consequences of today’s alimentary behavior. This study evaluates the effects of a chronic-discontinuous treatment with alpha-lipoic acid (AL), an antioxidant substance that improves glycemic control associated with diabetes mellitus, on metabolic disorders and plasma oxidative stress induced by fructose intake, in rats. Sprague-Dawley rats (48 animals) were randomized into two series (n = 24): rats fed with standard chow or with standard chow supplemented with 60% fructose. In each of the two series, for 2 weeks/month over 12 weeks, a group of rats (n = 12) was intraperitoneally injected with NaCl 0.9%, and a second group (n = 12) received AL 50 mg/kg/day. Body weight, glycemia, and systolic blood pressure were monitored throughout the study. After 12 weeks, IR, plasma lipoproteins, uric acid, transaminase activities, and oxidative stress markers were assessed. The high fructose-enriched diet induced cardiometabolic disorders (hypertension, hyperglycemia, IR and dyslipidemia), an increase in uric acid concentration, transaminase activities and C-reactive protein level. This diet also enhanced plasma products of lipid and protein oxidation, homocysteine level, and decreased GSH/GSSG ratio. In this field, there is evidence to indicate that oxidative stress plays an important role in the etiology of diabetic complications. AL discontinuous treatment prevents the metabolic disorders induced by fructose intake, reduced plasma lipid and protein oxidation-products, and restored the GHS/GSSG ratio. Our study proves a promising potential of the chronic-discontinuous treatment of AL and highlights the pleiotropic effects of this antioxidant substance in metabolic disorders such as diabetes.

Germacrone cooperates with dexmedetomidine to alleviate high-fat diet-induced type 2 diabetes mellitus via upregulating AMPKα1 expression

The aim of the present study was to investigate the effects of germacrone (GM) and dexmedetomidine (DEX) in treating type 2 diabetes mellitus (T2DM). A high-fat diet (HFD)-induced T2DM rat model was established. The experimental rats were divided into the control group, HFD group, GM treatment group, DEX treatment group and GM + DEX treatment group. In addition, adenosine monophosphate-activated protein kinase (AMPK) inhibitor compound C (CC) was used to inhibit AMPKα1 expression. All rats received their respective treatment daily for 21 days. Blood glucose and lipid levels, apoptosis of hepatic cells, and levels of inflammatory factors and oxidative stress indicators in serum samples were evaluated. Protein expression of AMPKα1 and its downstream targets were also investigated. Results demonstrated that blood glucose concentration, blood lipid indicators (endothelin, total cholesterol, triglyceride and low density lipoprotein cholesterol), cell apoptosis in liver tissues, total oxidant status, malondialdehyde, interleukin (IL)-6, tumor necrosis factor-α (TNF-α) and IL-1β levels in serum were increased in the high-fat group compared to the control but decreased following GM and/or DEX treatment. By contrast, high-density lipoprotein cholesterol and antioxidative stress indicator superoxide dismutase (SOD) were decreased in the high-fat group but increased following GM and/or DEX treatment. Protein expression of AMPKα1 and the catabolic genes carnitine palmitoyltransferase-1, peroxisome proliferator-activated receptor-α and acyl coenzyme A were decreased whilst anabolic genes, including sterol regulatory element binding protein-1c, fatty acid synthase and diacylglycerol acyltransferase-2, were increased in the HFD group. These effects were attenuated by GM and/or DEX treatment. AMPKα1 inhibition resulted in decreased SOD and increased cell apoptosis in liver tissues as well as increased IL-6, TNF-α and IL-1β levels compared with the HFD group. However, these effects were abolished following treatment with CC, GM and DEX together. Taken together these results indicated that GM worked synergistically with DEX to attenuate symptoms of high-fat-induced T2DM, with the effect potentially involving an increase in AMPKα1 expression.

Selected elements of extracellular matrix of the skin in diabetes and insulin resistance

PURPOSE

Reconstruction of the skin extracellular matrix is a physiological phenomenon occurring on a continuous basis. The aim of this study is to evaluate the content of basic enzymes preventing oxidative stress: superoxide dismutase 2 and 3 as well as catalase, the content of hyaluronic acid, and the activity of N-acetyl-β-d-hexosaminidase and β-d-glucuronidase in the skin of rats used as animal models of diabetes and insulin resistance, before and after the treatment.

MATERIALS AND METHODS

The study was conducted on a group of sexually mature male Wistar rats divided into 7 groups of 10 animals. Insulin resistance was induced by feeding the rats with a high-fat diet, and diabetes was induced by a single injection of streptozotocin. Chosen groups of rats were treated with insulin or metformin. After 8 weeks, we excised a fragment of shaved dorsal skin from anesthetized rats in each group.

RESULTS

In the course of diabetes and insulin resistance, an intensified defensive activity of cells against the oxidative stress was observed in the undamaged skin, expressed by an increase in the relative content of superoxide dismutase 2 and 3, catalase and the activity of N-acetyl-β-d-hexosaminidase and β-d-glucuronidase. Diabetes and insulin resistance cause similar skin damage, as there are no differences in the relative contents or specific activities of the examined parameters.

CONCLUSIONS

Insulin and metformin improve the quality of the skin in rats with diabetes and insulin resistance, by restoring the content of hyaluronic acid to the healthy skin level.

Potency of Okra flour (Abelmoschus esculentus) in improving adiponectin level and total antioxidant capacity of high fat diet streptozotocin rat model

T2DM has increase in global-morbidity and mortality. Oxidative stress and adiponectin-levels are important for insulin-resistance and pancreatic-b-cell-dysfunction in T2DM. Okra fruit is rich of quercetin and phytosterol which have positive-effect for T2DM. Research aimed was to study the effect of okra-flour to adiponectin-levels and total-antioxidant-capacity (TAC) in T2DM. Thirty Wistar-rats were divided randomly in five groups. K1 and (X1, X2 and X3)-treated-groups were in T2DM-condition-induced by high-fat-diet-(HFD)-Streptozotochin-(STZ)-nicotinamid-(NA). Healthy-controls-(K2)-group was also used. Okra-flour was given orally for 28 days at doses of 0.1; 0.2 and 0.3 g/Kg-body-weight/d to X1, X2 and X3-groups, respectively. Statistical program was used to analyse the different between pre-post-intervention, and between groups. Correlations between variables were also analysed. The serum-adiponectin and TAC-levels were measured by ELISA and ABTS-methods, respectively. By comparing pre and post-intervention, adiponectin levels of all-intervention-(X1, X2, X3)-group were  increase (p = 0.027 for X1 and X2; p = 0.028 for X3), while in the same period the decrease were found in group K1 (p = 0.026) and K2 (p = 0.028). Increase-TAC-levels pre-post-intervention was observed in group all-intervention-groups (p = 0.027), while no change in K1 (p = 0.66) and the decrease in group K2 (p = 0.039). Reduce-fasting-blood-glucose-levels pre-post-intervention were shown in the all-intervention-groups (p = 0.028), while for the K1 groups was increase (p = 0.028). There were significant differences between the five-groups on fasting-blood-glucose-levels, adiponectin and TAC-levels, and X3-group showed the highest adiponectin and TAC-levels. Very-strong-correlations were found between glucose-adiponectin-TAC-levels-post-intervention. Okra-flour make better glucose-adiponectin and TAC-levels in T2DM-conditions. Okra dose of 0.30 g/Kg-body-weight/day is the best in increasing adiponectin and TAC-levels.

MicroRNA‑802 increases hepatic oxidative stress and induces insulin resistance in high‑fat fed mice

The expression of microRNA-802 (miR-802) is known to be associated with insulin resistance (IR); however, the mechanism remains unclear. The present study investigated how miR-802 contributes to the development of IR using C57BL/6J mice fed a high-fat diet (HFD) to establish a model of IR. Adeno-associated virus overexpressing miR-802 was administered to the mice via tail vein injection. The effects of miR-802 on reactive oxygen species (ROS), lipid peroxidation (LPO) and the activities of multiple ROS-related enzymes were investigated. Western blot analysis was used to estimate the protein levels of extracellular signal regulated kinase (ERK), p38mitogen-activated protein kinases (p38MAPK), c-Jun N-terminal kinase (JNK), insulin receptor substrate 1 (IRS-1) and protein kinase B (AKT1). The results demonstrated that the levels of ROS and LPO production were increased in the livers of the miR-802-treated group compared with the control group. The activities of the ROS-related enzymes were reduced. Furthermore, the expression of phosphorylated (phosphor)-p38MAPK and phosphor-JNK were upregulated in the miR-802 overexpression group, whereas there was no difference in the expression levels of phosphor-ERK. The expression levels of phosphor-AKT1 were reduced in the miR-802-treated group and these effects were reversed by miR-802 knockdown. In conclusion, the results demonstrate that miR-802 may cause IR by activating the JNK and p38MAPK pathways to increase hepatic oxidative stress.

Molecular aspects of pancreatic β-cell dysfunction: Oxidative stress, microRNA, and long noncoding RNA

Metabolic syndrome is known as a frequent precursor of type 2 diabetes mellitus (T2D). This disease could affect 8% of the people worldwide. Given that pancreatic β-cell dysfunction and loss have central roles in the initiation and progression of the disease, the understanding of cellular and molecular pathways associated with pancreatic β-cell dysfunction can provide more information about the underlying pathways involved in T2D. Multiple lines evidence indicated that oxidative stress, microRNA, and long noncoding RNA play significant roles in various steps of diseases. Oxidative stress is one of the important factors involved in T2D pathogenesis. This could affect the function and survival of the β cell via activation or inhibition of several processes and targets, such as receptor-signal transduction, enzyme activity, gene expression, ion channel transport, and apoptosis. Besides oxidative stress, microRNAs and noncoding RNAs have emerged as epigenetic regulators that could affect pancreatic β-cell dysfunction. These molecules exert their effects via targeting a variety of cellular and molecular pathways involved in T2D pathogenesis. Here, we summarized the molecular aspects of pancreatic β-cell dysfunction. Moreover, we highlighted the roles of oxidative stress, microRNAs, and noncoding RNAs in pancreatic β-cell dysfunction.

Ameliorative Effect and Mechanism of the Purified Anthraquinone-Glycoside Preparation from Rheum Palmatum L. on Type 2 Diabetes Mellitus

Rheum palmatum L. is a traditional Chinese medicine with various pharmacological properties, including anti-inflammatory, antibacterial, and detoxification effects. In this study, the mechanism of the hypoglycemic effect of purified anthraquinone-Glycoside from Rheum palmatum L. (PAGR) in streptozotocin (STZ) and high-fat diet induced type 2 diabetes mellitus (T2DM) in rats was investigated. The rats were randomly divided into normal (NC), T2DM, metformin (Met), low, middle (Mid), and high (Hig) does of PAGR groups. After six weeks of continuous administration of PAGR, the serum indices and tissue protein expression were determined, and the pathological changes in liver, kidney, and pancreas tissues were observed. The results showed that compared with the type 2 diabetes mellitus group, the fasting blood glucose (FBG), total cholesterol (TC), and triglyceride (TG) levels in the serum of rats in the PAGR treatment groups were significantly decreased, while superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) levels were noticeably increased. The expression of Fas ligand (FasL), cytochrome C (Cyt-c), and caspase-3 in pancreatic tissue was obviously decreased, and the pathological damage to the liver, kidney, and pancreas was improved. These indicate that PAGR can reduce oxidative stress in rats with diabetes mellitus by improving blood lipid metabolism and enhancing their antioxidant capacity, thereby regulating the mitochondrial apoptotic pathway to inhibitβ-cell apoptosis and improve β-cell function. Furthermore, it can regulate Fas/FasL-mediated apoptosis signaling pathway to inhibit β-cell apoptosis, thereby lowering blood glucose levels and improving T2DM.

Developmental programming: Changes in mediators of insulin sensitivity in prenatal bisphenol A-treated female sheep

Developmental exposure to endocrine disruptor bisphenol A (BPA) is associated with metabolic defects during adulthood. In sheep, prenatal BPA treatment causes insulin resistance (IR) and adipocyte hypertrophy in the female offspring. To determine if changes in insulin sensitivity mediators (increase in inflammation, oxidative stress, and lipotoxicity and/or decrease in adiponectin) and the intracrine steroidal milieu contributes to these metabolic perturbations, metabolic tissues collected from 21-month-old female offspring born to mothers treated with 0, 0.05, 0.5, or 5 mg/kg/day of BPA were studied. Findings showed prenatal BPA in non-monotonic manner (1) increased oxidative stress; (2) induced lipotoxicity in liver and muscle; and (3) increased aromatase and estrogen receptor expression in visceral adipose tissues. These changes are generally associated with the development of peripheral and tissue level IR and may explain the IR status and adipocyte hypertrophy observed in prenatal BPA-treated female sheep.

Heterogeneity of Metabolic Defects in Type 2 Diabetes and Its Relation to Reactive Oxygen Species and Alterations in Beta-Cell Mass

Type 2 diabetes (T2D) is a complex and heterogeneous disease which affects millions of people worldwide. The classification of diabetes is at an interesting turning point and there have been several recent reports on sub-classification of T2D based on phenotypical and metabolic characteristics. An important, and perhaps so far underestimated, factor in the pathophysiology of T2D is the role of oxidative stress and reactive oxygen species (ROS). There are multiple pathways for excessive ROS formation in T2D and in addition, beta-cells have an inherent deficit in the capacity to cope with oxidative stress. ROS formation could be causal, but also contribute to a large number of the metabolic defects in T2D, including beta-cell dysfunction and loss. Currently, our knowledge on beta-cell mass is limited to autopsy studies and based on comparisons with healthy controls. The combined evidence suggests that beta-cell mass is unaltered at onset of T2D but that it declines progressively. In order to better understand the pathophysiology of T2D, to identify and evaluate novel treatments, there is a need for in vivo techniques able to quantify beta-cell mass. Positron emission tomography holds great potential for this purpose and can in addition map metabolic defects, including ROS activity, in specific tissue compartments. In this review, we highlight the different phenotypical features of T2D and how metabolic defects impact oxidative stress and ROS formation. In addition, we review the literature on alterations of beta-cell mass in T2D and discuss potential techniques to assess beta-cell mass and metabolic defects in vivo.

The therapeutic effects of resveratrol on hepatic steatosis in high-fat diet-induced obese mice by improving oxidative stress, inflammation and lipid-related gene transcriptional expression

So far, the majority of the previous animal studies have focused on the preventive effects of resveratrol (RSV) on non-alcoholic fatty liver disease (NAFLD) rather than the therapeutic effects. In this study, the therapeutic effects of RSV on hepatic oxidative stress (OS), inflammation, and lipid metabolism-related gene expression of obese mice induced by a high-fat diet (HFD) were investigated. Male C57BL/6 mice were fed a HFD for 8 weeks to induce obesity-related NAFLD model. And then, NAFLD mice were treated with daily RSV oral gavage at the dose of 100 mg/kg body weight for an additional 4 weeks. HFD-induced the elevation of serum total cholesterol, high-density lipoprotein cholesterol, glucose, insulin, aspartate aminotransferase and alanine aminotransferase levels, and homeostasis model assessment of insulin resistance, hepatic histology changes, the increases in hepatic triglyceride, malondialdehyde and tumor necrosis factor alpha concentrations, as well as the higher mRNA expression of hepatic toll-like receptor 4 and cluster of differentiation 36 in mice, were restored by RSV. The therapeutic effects of RSV against hepatic steatosis of HFD obese mice were attributed to the reduction of OS, inflammation and free fatty acid uptake.

Dynamic, Not Isometric Resistance Training Improves Muscle Inflammation, Oxidative Stress and Hypertrophy in Rats

This study aimed to compare the effects of dynamic (DRT) and isometric (IRT) resistance training on blood glucose, muscle redox capacity, inflammatory state, and muscle strength and hypertrophy. Fifteen 12-week-old male Wistar rats were randomly allocated into three groups: control group (CTL), DRT, and IRT, n = 5 animals per group. The animals were submitted to a maximal weight carried (MWC; every 15 days) and maximum isometric resistance (MIR; pre- and post-training) tests. Both training protocols were performed five times a week during 12 weeks, consisting of one set of eight uninterrupted climbs for 1 min with a 30% overload of MWC. The animals in the IRT group remained under isometry for 1 min. The DRT group experienced greater MWC from pre- to post-training compared to the CTL and IRT groups (p < 0.0001). The DRT and IRT groups displayed similar gains in MIR (p = 0.3658). The DRT group exhibited improved glycemic homeostasis (p = 0.0111), redox (p < 0.0001), and inflammatory (p < 0.0001) balance as compared with CTL and IRT groups. In addition, the improved glycemic profile was associated with an increase in muscle strength and hypertrophy, improvement in redox balance and inflammation status. We conclude that DRT was more effective than IRT on increasing cross-sectional area, but not muscle strength, in parallel to improved blood glucose, inflammatory status, and redox balance.

Oxidative Modifications in Tissue Pathology and Autoimmune Disease

SIGNIFICANCE

Various autoimmune syndromes are characterized by abnormalities found at the level of tissues and cells, as well as by microenvironmental influences, such as reactive oxygen species (ROS), that alter intracellular metabolism and protein expression. Moreover, the convergence of genetic, epigenetic, and even environmental influences can result in B and T lymphocyte autoimmunity and tissue pathology. Recent Advances: This review describes how oxidative stress to cells and tissues may alter post-translational protein modifications, both directly and indirectly, as well as potentially lead to aberrant gene expression. For example, it has been clearly observed in many systems how oxidative stress directly amplifies carbonyl protein modifications. However, ROS also lead to a number of nonenzymatic spontaneous modifications including deamidation and isoaspartate modification as well as to enzyme-mediated citrullination of self-proteins. ROS have direct effects on DNA methylation, leading to influences in gene expression, chromosome inactivation, and the silencing of genetic elements. Finally, ROS can alter many other cellular pathways, including the initiation of apoptosis and NETosis, triggering the release of modified intracellular autoantigens.

CRITICAL ISSUES

This review will detail specific post-translational protein modifications, the pathways that control autoimmunity to modified self-proteins, and how products of ROS may be important biomarkers of tissue pathogenesis.

FUTURE DIRECTIONS

A clear understanding of the many pathways affected by ROS will lead to potential therapeutic manipulations to alter the onset and/or progression of autoimmune disease.

Potency of Cape Gooseberry (Physalis Peruviana) Juice in Improving Antioxidant and Adiponectin Level of High Fat Diet Streptozotocin Rat Model

Background and aims: Quercetin belonging flavonoid has a role to improve diabetic condition. Research aimed to examine and to compare Cape Gooseberry (CG) juice and quercetin supplement on Total Antioxidant Capacity (TAC) and adiponectin level of high fat diet-Streptozotocin (HFD-STZ) induced rat.

Material and method: CG juice 5 ml/kg/d (X1) and 25 ml/kg/d (X2) groups; and quercetin supplement 2.2 mg/kg/d (X3) and 30 mg/kg/d (X4) groups were compared with both of positive (K+) and negative (K-) control. Treatments were given by orally gavage for 28 days to 36 Wistar rats which each group consisted of 6 rats. TAC and adiponectin level were measured by ABTS and ELISA method respectively.

Results: There was significantly increase of TAC in treatment groups compared with K(+) (p<0.05). X2 had TAC level significantly higher than X1 (p=0.025). Moreover, adiponectin level of treatment groups were significantly higher than K(+) (p<0.05). Furthermore, X2 had adiponectin level significantly higher than X3 (p<0.001).

Conclusion: CG juice 25 ml/kg/d presented better effect than CG juice 5 ml/kg/d, although quercetin 30 mg/kg/d showed the best effects toward both of TAC and adiponectin.

Radio-Protective Effects of Octopus ocellatus Meat Consisted of a Plentiful Taurine Against Damages Caused by Gamma Ray Irradiation

Gamma ray irradiation causes immune suppressive responses by inducing oxidative stress such as reduction of cell viability and damages in immune cells. In this present study, we investigated whether Octopus ocellatus meet (OM) consisted of a plentiful taurine has protective effects against damages caused by oxidative stress in murine splenocytes. First of all, we prepared the aqueous extract from OM (OMA) and identified it contained a plentiful taurine content. The result also showed that OMA exhibited the antioxidant activity by scavenging DPPH and ABTS+ radicals and hydrogen peroxide. In addition, OMA improved the cell viability without cytotoxicity in gamma ray-irradiated murine splenocytes. Moreover, OMA significantly reduced the production of reactive oxygen species (ROS) in gamma ray-irradiated splenocytes. In further study, we identified that OMA protected zebrafish embryo via improving the reduced survival rate and decreasing the formation of deformity caused by the exposure of gamma ray irradiation. Also, OMA decreased the production of NO and ROS in gamma ray-irradiated zebrafish embryos as well as the induction of cell death. In these results, this study suggests that the consumption of taurine-rich foods, such as O. ocellatus, may be useful for the useful material for the protection against oxidative stress.

Exploring the association between polycyclic aromatic hydrocarbons and diabetes among adults in the United States

OBJECTIVE

To explore the association between polycyclic aromatic hydrocarbons (PAHs) and diabetes and to determine whether effects are heterogeneous when examined by body mass index (BMI).

METHODS

Cross-sectional data from 8664 participants were analyzed from the National Health and Nutrition Examination Survey for years 2005-2014. Multivariable logistic regression was used to explore the association between urinary biomarkers of PAHs and diabetes. All models were adjusted for age, sex, race, poverty-income ratio, and serum cotinine.

RESULTS

When compared with the lowest quintiles of exposure, the highest quintiles of exposure to 2-hydroxynaphthalene, 2-hydroxyfluorene, 9-hydroxyfluorene, 2-hydroxyphenanthrene, and a summed variable of all low molecular weight PAHs (aOR = 1.73; 95% CI: 1.17-2.55) showed a positive association with diabetes. Stratified analyses by BMI indicated that the positive association between PAHs and diabetes was found among both normal weight and obese participants.

CONCLUSIONS

High levels of exposure to PAHs are positively associated with diabetes in the U.S. general population and these effects are modified by BMI. These findings suggest the importance of strong environmental regulation of PAHs to protect population health.

Molecular pathways associated with oxidative stress in diabetes mellitus

The role of oxidative stress in the occurrence and development of diabetes mellitus is both critical and pivotal. Several molecular event cascade in different metabolic pathways such as glycolytic, hexosamine, protein kinase C, polyol and advanced glycation end-product (AGE) pathways have been identified as pro-oxidative processes and are usually up-regulated in the diabetics. Inhibition of glyceraldehyde-3-P dehydrogenase by poly-ADP-ribose polymerase 1 and subsequent accumulation of the enzyme substrate (glyceraldehyde-3-P) appears to be central to diabetes-associated oxidative stress. Increased level of glyceraldehyde-3-P activates two major pro-oxidative pathways in diabetes: (i) It activates the AGE pathway, precisely the synthesis of methylglyoxal from non-enzymatic dephosphorylation of the triose phosphates (ii) It activates protein kinase C (PKC) pathway by promoting the synthesis of diacylglycerol. In addition, it causes the accumulation of glycolytic metabolites upstream, and this leads to excessive stimulation of other pro-oxidative pathways such as hexosamine and polyol pathways. This review tends to highlight the main oxidative processes associated with diabetes mellitus.

Oxidative status of cardinal ligament in pelvic organ prolapse

Pelvic organ prolapse (POP) is a common and distressing health problem in adult women, but the pathophysiological mechanism is yet to be fully elucidated. Previous studies have indicated that oxidative stress may be associated with POP. Thus, the aim of the present study was to investigate the oxidative status of pelvic supportive tissue in POP and further demonstrate that oxidative stress is associated with the pathogenesis of POP. A total of 60 samples were collected from females undergoing hysterectomy for POP or cervical intraepithelial neoplasia (CIN). This included 16 females with POP II, 24 females with POP III–IV (according to the POP-Q system) and 20 females with CIN II–III as the control group. Immunohistochemistry was utilized to measure the expression of oxidative biomarkers, 8-hydroxydeoxyguanosine (8-OHdG) and 4-hydroxynonenal (4-HNE). Major antioxidative enzymes, mitochondrial superoxide dismutase (MnSOD) and glutathione peroxidase 1 (GPx1) were measured through reverse transcription-quantitative polymerase chain reaction, western blotting and enzyme activity assays. The results demonstrated that in the cardinal ligament, the expression of 8-OHdG and 4-HNE was higher in the POP III–IV group compared with the POP II group and control group. The MnSOD and GPx1 protein level and enzyme activity were lower in the POP III–IV group compared with the POP II or the control group, while the mRNA expression level of MnSOD and GPx1 was increased. In conclusion, oxidative damage is increased in the pelvic supportive ligament of female patients with POP and the antioxidative defense capacity is decreased. These results support previous findings that oxidative stress is involved in the pathogenesis of POP.

The effects of vitamin D and probiotic co-supplementation on mental health parameters and metabolic status in type 2 diabetic patients with coronary heart disease: A randomized, double-blind, placebo-controlled trial

BACKGROUND

This study was carried out to evaluate the effects of vitamin D and probiotic co-supplementation on mental health parameters and metabolic status in diabetic people with coronary heart disease (CHD).

METHODS

This randomized, double-blind, placebo-controlled trial was carried out among 60 diabetic people with CHD, aged 45-85 years old. Subjects were randomly allocated into two groups to receive either 50,000 IU vitamin D every 2 weeks plus 8 × 10⁹ CFU/g probiotic of Lactocare Zisttakhmir Co (n = 30) or placebo (n = 30) for 12 weeks. Fasting blood samples were obtained at baseline and after the 12-week intervention to determine metabolic profiles.

RESULTS

After the 12-week intervention, compared with the placebo, vitamin D and probiotic co-supplementation resulted in significant improvements in beck depression inventory total score (-2.8 ± 3.8 vs. -0.9 ± 2.1, P = 0.01), beck anxiety inventory scores (-2.1 ± 2.3 vs. -0.8 ± 1.4, P = 0.009) and general health questionnaire scores (-3.9 ± 4.1 vs. -1.1 ± 3.4, P = 0.005). Compared with the placebo, vitamin D and probiotic co-supplementation resulted in significant reductions in serum insulin levels (-2.8 ± 3.8 vs. +0.2 ± 4.9 μIU/mL, P = 0.009), homeostasis model of assessment-estimated insulin resistance (-1.0 ± 1.6 vs. -0.1 ± 1.5, P = 0.02), and a significant increase in serum 25-OH-vitamin D (+11.8 ± 5.9 vs. +0.1 ± 1.4 ng/mL, P < 0.001), the quantitative insulin sensitivity check index (+0.03 ± 0.04 vs. -0.001 ± 0.01, P = 0.003) and serum HDL-cholesterol levels (+2.3 ± 3.5 vs. -0.5 ± 3.8 mg/dL, P = 0.004). In addition, changes in serum high sensitivity C-reactive protein (hs-CRP) (-950.0 ± 1811.2 vs. +260.5 ± 2298.2 ng/mL, P = 0.02), plasma nitric oxide (NO) (+1.7 ± 4.0 vs. -1.4 ± 6.7 μmol/L, P = 0.03) and plasma total antioxidant capacity (TAC) (+12.6 ± 41.6 vs. -116.9 ± 324.2 mmol/L, P = 0.03) in the supplemented group were significantly different from the changes in these indicators in the placebo group.

CONCLUSIONS

Overall, vitamin D and probiotic co-supplementation after 12 weeks among diabetic people with CHD had beneficial effects on mental health parameters, serum hs-CRP, plasma NO, TAC, glycemic control and HDL-cholesterol levels.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.irct.ir: IRCT2017073033941N4.

Ginkgo Biloba L. Extract Reduces H2O2-Induced Bone Marrow Mesenchymal Stem Cells Cytotoxicity by Regulating Mitogen-Activated Protein Kinase (MAPK) Signaling Pathways and Oxidative Stress

Background

The oxidative stress environment of pathological tissue has an adverse effect on the survival of bone marrow mesenchymal stem cells (BMSCs) transplantation. Ginkgo biloba L. extract (EGB) has a potent antioxidant effect. In this research, we assessed the protective effects of EGB and EGB-Containing Serum (EGB CS) on BMSCs against injury induced by hydrogen peroxide (H₂O₂).

Material/Methods

BMSCs were pretreated with EGB or EGB CS and treated with H₂O₂. The cell counting kit-8 (CCK-8) method was utilized to detect cell viability. The DCFH-DA Fluorescent Kit method was used to detect intracellular ROS level. Malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and (CAT) were determined. The Hoechst staining assay and qRT-PCR assay were utilized to evaluate the effect of EGB on cell apoptosis. Mitogen-activated protein kinases (MAPKs) signaling pathway were detected by western blot analysis.

Results

Compared to the H₂O₂ group, the number of apoptotic cells in the EGB and EGB CS pretreated groups significantly decreased. The mRNA expression ratio of Bax/Bcl-2 was also decreased. EGB and EGB CS can reduce the production of ROS in BMSCs exposed to H₂O₂. SOD, GSH-Px and CAT activities were significantly higher compared with those with H₂O₂ group. Furthermore, EGB or EGB CS pretreatment decreased the protein levels of p-p38MAPK and p-JNK in BMSCs compared to the H₂O₂ group.

Conclusions

Our findings suggested that EGB and EGB CS have protective effect on BMSCs against oxidative stress injury and increase the survival rate of BMSCs transplantation by regulating p38MAPK and JNK signaling.

Sources of free radicals and oxidative stress in the oral cavity

OBJECTIVE

An oral cavity is a place especially susceptible to oxidative damage. It is subjected to many environmental pro-oxidative factors or factors that have the ability to generate reactive oxygen species (ROS). The aim of this article is to present the main sources of ROS and oxidative stress in the oral environment.

DESIGN

A literature search was performed using the PubMed and Google Scholar databases.

RESULTS

One of the most important ROS sources in the oral cavity is periodontal inflammation. Other sources of ROS include: xenobiotics (ethanol, cigarette smoke, drugs), food (high-fat diet, high-protein diet, acrolein), dental treatment (ozone, ultrasound, non-thermal plasma, laser light, ultraviolet light), and dental materials (fluorides, dental composites, fixed orthodontic appliances, and titanium fixations). It has been shown that excessive production of ROS in the oral cavity may cause oxidative stress and oxidative damage to cellular DNA, lipids, and proteins, thus predisposing to many oral and systemic diseases.

CONCLUSIONS

Recognition of the exogenous sources of ROS and limitation of exposure to the ROS generating factors can be one of the prophylactic measures preventing oral and systemic diseases. It is suggested that antioxidant supplementation may be helpful in people exposed to excessive production of ROS in the oral cavity system.

Coumarins improved type 2 diabetes induced by high-fat diet and streptozotocin in mice via antioxidation

Coumarins extensively exist in plants and are utilized against diabetes in some folk medicines. Recent studies have demonstrated that oxidative stress plays a crucial role in the etiology and pathogenesis of diabetes mellitus. We investigated the antioxidant ability of 3 coumarins (osthole, esculin, and fraxetin) in type 2 diabetes. After being fed a high-fat diet, ICR mice were exposed to low doses of streptozotocin and then treated with experimental coumarins for 5 weeks. We found osthole, esculin, and metformin significantly lowered fasting blood glucose, HOMA-IR, and 3 blood lipids (total cholesterol, total triglyceride, free fatty acids), and increased insulin levels, while fraxetin only enhanced insulin levels and lessened free fatty acids. Both osthole and esculin had antioxidative effects in pancreas through elevating the activities of glutathione peroxidase, catalase, and superoxide dismutase; fraxetin, however, merely heightened catalase activity. By contrast, 3 coumarins significantly increased those antioxidase activities in liver. Hematoxylin and eosin staining revealed 3 coumarins, especially osthole, attenuated cellular derangement, blurry fringes of hepatic sinusoid and extensive vacuolization due to hepatocellular lipid accumulation, and lessened inflammatory infiltration in pancreas. The glomerular and islet structure of diabetic mice were improved, with reduced mesangial matrix and glomerular basement membrane thickening. Therefore, our study supports that coumarins could be promising candidates against type 2 diabetes through antioxidative mechanisms.

A Positive Feedback Loop of Profilin-1 and RhoA/ROCK1 Promotes Endothelial Dysfunction and Oxidative Stress

Vascular endothelial dysfunction is considered critical development in the progression of cardiovascular events and is associated with vascular damage and oxidative stress. Previous studies have shown that profilin-1 could be induced by advanced glycation end products (AGEs) and contributes to vascular hyperpermeability; however, the mechanisms are not fully understood. In this study, we sought to assess whether reactive oxygen species (ROS) were involved in profilin-1-mediated RhoA/ROCK1 signaling. Treatment with AGEs significantly induced the expression of profilin-1 and ROS production in human umbilical vein endothelial cells (HUVECs), whereas knockdown of profilin-1 diminished AGE-induced RhoA and ROCK1 activation and ROS production. Moreover, ectopic overexpression of profilin-1 also increased RhoA and ROCK1 activation and ROS production under low AGE concentration. Furthermore, blockage of RhoA/ROCK1 with the inhibitors CT04 and Y27632 significantly attenuated the profilin-1-mediated cell damage and ROS production. Additionally, ROS inhibition resulted in a significant decrease in profilin-1-mediated RhoA/ROCK1 expression, suggesting that the regulation of RhoA/ROCK1 signaling was partly independent of ROS. Taken together, these results suggested that the RhoA/ROCK1 pathway activated by excessive ROS is responsible for profilin-1-mediated endothelial damage.

(-)-Epicatechin and its metabolites prevent palmitate-induced NADPH oxidase upregulation, oxidative stress and insulin resistance in HepG2 cells

While diets rich in fruit and vegetables can decrease the risk for type 2 diabetes (T2D), diets rich in fat and carbohydrates can increase it. The flavanol-3-ol (-)-epicatechin (EC) can improve insulin sensitivity both in humans and animal models of T2D. NADPH oxidases and oxidative stress can contribute to the development of insulin resistance. This study investigated the capacity of EC and EC metabolites (ECM) to downregulate NADPH oxidases and oxidative stress, and its association to an improvement of insulin sensitivity. This was studied in in vivo (high fat-fed mice) and in vitro (HepG2 cells) conditions of hepatic lipid overload. EC decreased NOX3/NOX4 liver expression and mitigated oxidative stress in high fat-fed mice. In HepG2 cells, incubation with palmitate increased: i) lipid deposition, ii) NOX3/NOX4 expression, iii) NADPH oxidase activity, and iv) oxidative stress; promoting v) the activation of redox-sensitive kinases (JNK and IKK), and vi) impaired insulin responses. Physiological concentrations of EC and ECM, and NADPH oxidase inhibitors (apocynin, VAS2870) prevented all those deleterious effects of palmitate. The obtained results points to NADPH oxidases as an important target in the capacity of EC to improve insulin sensitivity in conditions of liver lipid overload, as those associated with Western-style diets.

Insulin-like growth factor receptor signaling regulates working memory, mitochondrial metabolism, and amyloid-β uptake in astrocytes

Objective

A decline in mitochondrial function and biogenesis as well as increased reactive oxygen species (ROS) are important determinants of aging. With advancing age, there is a concomitant reduction in circulating levels of insulin-like growth factor-1 (IGF-1) that is closely associated with neuronal aging and neurodegeneration. In this study, we investigated the effect of the decline in IGF-1 signaling with age on astrocyte mitochondrial metabolism and astrocyte function and its association with learning and memory.

Methods

Learning and memory was assessed using the radial arm water maze in young and old mice as well as tamoxifen-inducible astrocyte-specific knockout of IGFR (GFAP-Cre^TAM/igfr^f/f). The impact of IGF-1 signaling on mitochondrial function was evaluated using primary astrocyte cultures from igfr^f/f mice using AAV-Cre mediated knockdown using Oroboros respirometry and Seahorse assays.

Results

Our results indicate that a reduction in IGF-1 receptor (IGFR) expression with age is associated with decline in hippocampal-dependent learning and increased gliosis. Astrocyte-specific knockout of IGFR also induced impairments in working memory. Using primary astrocyte cultures, we show that reducing IGF-1 signaling via a 30–50% reduction IGFR expression, comparable to the physiological changes in IGF-1 that occur with age, significantly impaired ATP synthesis. IGFR deficient astrocytes also displayed altered mitochondrial structure and function and increased mitochondrial ROS production associated with the induction of an antioxidant response. However, IGFR deficient astrocytes were more sensitive to H₂O₂-induced cytotoxicity. Moreover, IGFR deficient astrocytes also showed significantly impaired glucose and Aβ uptake, both critical functions of astrocytes in the brain.

Conclusions

Regulation of astrocytic mitochondrial function and redox status by IGF-1 is essential to maintain astrocytic function and coordinate hippocampal-dependent spatial learning. Age-related astrocytic dysfunction caused by diminished IGF-1 signaling may contribute to the pathogenesis of Alzheimer's disease and other age-associated cognitive pathologies.

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Altered mitochondrial structure and function with IGFR deficiency in astrocytes is proposed.

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Increased reactive oxygen species production and susceptibility to peroxide induced cytotoxicity.

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Decreased Aβ uptake and impairment in spatial working memory.

Nutrients and Oxidative Stress: Friend or Foe?

There are different types of nutritionally mediated oxidative stress sources that trigger inflammation. Much information indicates that high intakes of macronutrients can promote oxidative stress and subsequently contribute to inflammation via nuclear factor-kappa B- (NF-κB-) mediated cell signaling pathways. Dietary carbohydrates, animal-based proteins, and fats are important to highlight here because they may contribute to the long-term consequences of nutritionally mediated inflammation. Oxidative stress is a central player of metabolic ailments associated with high-carbohydrate and animal-based protein diets and excessive fat consumption. Obesity has become an epidemic and represents the major risk factor for several chronic diseases, including diabetes, cardiovascular disease (CVD), and cancer. However, the molecular mechanisms of nutritionally mediated oxidative stress are complex and poorly understood. Therefore, this review aimed to explore how dietary choices exacerbate or dampen the oxidative stress and inflammation. We also discussed the implications of oxidative stress in the adipocyte and glucose metabolism and obesity-associated noncommunicable diseases (NCDs). Taken together, a better understanding of the role of oxidative stress in obesity and the development of obesity-related NCDs would provide a useful approach. This is because oxidative stress can be mediated by both extrinsic and intrinsic factors, hence providing a plausible means for the prevention of metabolic disorders.

Effect of N-Acetylcysteine on Antioxidant Defense, Oxidative Modification, and Salivary Gland Function in a Rat Model of Insulin Resistance

Oxidative stress plays a crucial role in the salivary gland dysfunction in insulin resistance (IR). It is not surprising that new substances are constantly being sought that will protect against the harmful effects of IR in the oral cavity environment. The purpose of this study was to evaluate the effect of N-acetylcysteine (NAC) on oxidative stress and secretory function of salivary glands in a rat model of insulin resistance. Rats were divided into 4 groups: C-normal diet, C + NAC-normal diet + NAC, HFD-high-fat diet, and HFD + NAC. We have demonstrated that NAC elevated enzymatic (superoxide dismutase, catalase, and peroxidase) and nonenzymatic antioxidants (reduced glutathione (GSH) and total antioxidant capacity (TAS)) in the parotid glands of HFD + NAC rats, while in the submandibular glands increased only GSH and TAS levels. NAC protects against oxidative damage only in the parotid glands and increased stimulated salivary secretion; however, it does not increase the protein secretion in the both salivary glands. Summarizing, NAC supplementation prevents the decrease of stimulated saliva secretion, seen in the HFD rats affected. NAC improves the antioxidative capacity of the both glands and protects against oxidative damage to the parotid glands of IR rats.

Testosterone Deficiency Causes Endothelial Dysfunction via Elevation of Asymmetric Dimethylarginine and Oxidative Stress in Castrated Rats

BACKGROUND

Testosterone is believed to mediate the penile erectile response by producing adequate nitric oxide; therefore, testosterone deficiency results in erectile dysfunction through decreased nitric oxide bioavailability. However, the mechanisms underlying endothelial dysfunction in testosterone deficiency remain unclear.

AIM

To investigate the mechanism of endothelial dysfunction in a rat model of testosterone deficiency.

METHODS

Rats were distributed into 3 groups: castrated (Cast), castrated and supplemented with testosterone (Cast + T), and sham (Sham). In the Cast + T group, castrated rats were treated daily with subcutaneous testosterone (3 mg/kg daily) for 4 weeks; Sham and Cast rats received only the vehicle.

OUTCOMES

Erectile function using intracavernosal pressure and mean arterial pressure measurements after electrical stimulation of the cavernous nerve, endothelial function using isometric tension, asymmetric dimethylarginine (ADMA) levels using ultra-performance liquid chromatography and tandem mass spectrometry, and inflammatory biomarker expression were performed 4 weeks after the operation.

RESULTS

In the Cast group, the ratio of intracavernosal pressure to mean arterial pressure significantly decreased, acetylcholine-induced relaxation was lower, and serum ADMA, oxidative stress, and inflammation biomarker levels were significantly increased (P < .01). Testosterone injection significantly improved each of these parameters (P < .01).

CLINICAL TRANSLATION

The present results provide scientific evidence of the effect of testosterone deficiency on erectile function and the effect of testosterone replacement therapy.

STRENGTHS AND LIMITATIONS

This study provides evidence of the influence of testosterone deficiency on endothelial function by investigating ADMA and oxidative stress. A major limitation of this study is the lack of a direct link of increased ADMA by oxidative stress to inflammation.

CONCLUSION

Testosterone deficiency increased not only ADMA levels but also oxidative stress and inflammation in castrated rats, which can cause damage to the corpus cavernosum, resulting in erectile dysfunction. Kataoka T, Hotta Y, Maeda Y, Kimura K. Testosterone Deficiency Causes Endothelial Dysfunction via Elevation of Asymmetric Dimethylarginine and Oxidative Stress in Castrated Rats. J Sex Med 2017;14:1540-1548.

The effects of probiotic supplementation on metabolic status in type 2 diabetic patients with coronary heart disease

BACKGROUND

This study was conducted to evaluate the effects of probiotic supplementation on metabolic profiles in diabetic patients with coronary heart disease (CHD).

METHODS

This randomized, double-blind, placebo-controlled trial was performed among 60 diabetic patients with CHD, aged 40-85 years at a cardiology clinic in Kashan, Iran, from October 2017 through January 2018. Patients were randomly divided into two groups to take either probiotic supplements (n = 30) or placebo (n = 30) for 12 weeks. Fasting blood samples were taken at the beginning of the study and after the 12-week intervention to determine related markers.

RESULTS

After 12-week intervention, probiotic supplementation significantly decreased fasting plasma glucose (β - 20.02 mg/dL; 95% CI - 33.86, - 6.17; P = 0.005), insulin (β - 2.09 µIU/mL; 95% CI - 3.77, - 0.41; P = 0.01), insulin resistance (β - 0.50; 95% CI - 0.96, - 0.03; P = 0.03) and total-/HDL-cholesterol ratio (β - 0.27; 95% CI - 0.52, - 0.03; P = 0.02), and significantly increased insulin sensitivity (β 0.008; 95% CI 0.001, 0.01; P = 0.02) and HDL-cholesterol levels (β 2.52 mg/dL; 95% CI 0.04, 5.00; P = 0.04) compared with the placebo. Moreover, probiotic supplementation led to a significant reduction in serum high sensitivity C-reactive protein (β - 0.88 mg/L; 95% CI - 1.39, - 0.38; P = 0.001), and a significant elevation in total antioxidant capacity (β 108.44 mmol/L; 95% CI 47.61, 169.27; P = 0.001) and total glutathione levels (β 45.15 µmol/L; 95% CI 5.82, 84.47; P = 0.02) compared with the placebo. Probiotic supplementation did not affect other metabolic profiles.

CONCLUSIONS

Overall, we found that probiotic supplementation for 12 weeks had beneficial effects on glycemic control, HDL-cholesterol, total-/HDL-cholesterol ratio, biomarkers of inflammation and oxidative stress in diabetic patients with CHD.Trial registration Clinical trial registration number http://www.irct.ir: IRCT2017082733941N5.

Effects of calcium dobesilate on Nrf2, Keap1 and HO-1 in the lenses of D-galactose-induced cataracts in rats

This study investigated the effects of calcium dobesilate on Nrf2, Keap1 and HO-1 in the lenses of D-galactose-induced cataracts in rats. Thirty Sprague-Dawley rats were randomly divided into three groups: a blank control group, a model control group and a model administration group. A normal diet was given to the rats in the blank control group and the rats with D-galactose-induced cataracts of the model control group. Calcium dobesilate was also given to the rats with D-galactose-induced cataracts of the model administration group. A slit lamp microscope was used to check the degree of lens opacity. RT-PCR and western blot analysis were used to detect the mRNA and protein expression of Nrf2, Keap1 and HO-1 in the lenses of the three groups. There was a significant difference in the degree of lens opacity among the three groups (P<0.05). The model control group was the most turbid of the three groups, followed by the model administration group. Moreover, the mRNA and protein expression of Nrf2, Keap1 and HO-1 in the lenses of the three groups were also significantly different (P<0.05). The mRNA levels of Nrf2 and HO-1 were the highest in the model control group, followed by the model administration group, and were the lowest in the blank control group. However, the mRNA expression level of Keap1 among the three groups had an opposite trend. In conclusion, calcium dobesilate can effectively increase the levels of Nrf2 and HO-1 in the lenses of diabetic cataract rats and inhibit the level of Keap1. Therefore, the therapeutic effect of calcium dobesilate against cataracts is related to the improvement of the Nrf2-Keap1 signaling pathway.

Indices of insulin resistance and glucotoxicity are not associated with bipolar disorder or major depressive disorder, but are differently associated with inflammatory, oxidative and nitrosative biomarkers

BACKGROUND

Insulin resistance (IR) is a key factor in diabetes mellitus, metabolic syndrome (MetS) and obesity and may occur in mood disorders and tobacco use disorder (TUD), where disturbances of immune-inflammatory, oxidative and nitrosative stress (IO&NS) pathways are important shared pathophysiological pathways.

METHODS

This study aimed to a) examine IR and β-cell function as measured by the homeostasis model assessment of insulin resistance (HOMA-IR) and insulin sensitivity and β cell function (HOMA-B) and glucotoxicity (conceptualized as increased glucose levels versus lowered HOMA-B values) in 74 participants with major depressive disorder (MDD) and bipolar disorder, with and or without MetS and TUD, versus 46 healthy controls, and b) whether IR is associated with IO&NS biomarkers, including nitric oxide metabolites (NOx), lipid hydroperoxides (LOOH), plasma advanced oxidation protein products (AOPP), C-reactive protein (CRP), haptoglobin (Hp) and uric acid.

RESULTS

Mood disorders are not associated with changes in IR or glucotoxicity, although the number of mood episodes may increase IR. 47.8% of the variance in HOMA-IR is explained by AOPP and body mass index (BMI, both positively) and NOx, Hp and TUD (all inversely). 43.2% of the variance in HOMA-B is explained by NOx, Hp and age (all inversely associated) and higher BMI and sex. The glucotoxic index is strongly associated with NOx, Hp and BMI (positively), male gender and lower education.

LIMITATIONS

This is a cross-sectional study and therefore we cannot draw firm conclusions on causal associations.

CONCLUSIONS

Activated IO&NS pathways (especially increased Hp and NOx) increase glucotoxicity and exert very complex effects modulating IR. Mood disorders are not associated with increased IR.

DHEA supplementation to dexamethasone-treated rabbits alleviates oxidative stress in kidney-cortex and attenuates albuminuria

Our recent study has shown that dehydroepiandrosterone (DHEA) administered to rabbits partially ameliorated several dexamethasone (dexP) effects on hepatic and renal gluconeogenesis, insulin resistance and plasma lipid disorders. In the current investigation, we present the data on DHEA protective action against dexP-induced oxidative stress and albuminuria in rabbits. Four groups of adult male rabbits were used in the in vivo experiment: (1) control, (2) dexP-treated, (3) DHEA-treated and (4) both dexP- and DHEA-treated. Administration of dexP resulted in accelerated generation of renal hydroxyl free radicals (HFR) and malondialdehyde (MDA), accompanied by diminished superoxide dismutase (SOD) and catalase activities and a dramatic rise in urinary albumin/creatinine ratio. Treatment with DHEA markedly reduced dexP-induced oxidative stress in kidney-cortex due to a decline in NADPH oxidase activity and enhancement of catalase activity. Moreover, DHEA effectively attenuated dexP-evoked albuminuria. Surprisingly, dexP-treated rabbits exhibited elevation of GSH/GSSG ratio, accompanied by a decrease in glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities as well as an increase in glucose-6-phosphate dehydrogenase (G6PDH) activity. Treatment with DHEA resulted in a decline in GSH/GSSG ratio and glutathione reductase (GR) activity, accompanied by an elevation of GPx activity. Interestingly, rabbits treated with both dexP and DHEA remained the control values of GSH/GSSG ratio. As the co-administration of DHEA with dexP resulted in (i) reduction of oxidative stress in kidney-cortex, (ii) attenuation of albuminuria and (iii) normalization of glutathione redox state, DHEA might limit several undesirable renal side effects during chronic GC treatment of patients suffering from allergies, asthma, rheumatoid arthritis and lupus. Moreover, its supplementation might be particularly beneficial for the therapy of patients with glucocorticoid-induced diabetes.

Functional and therapeutic potential of inulin: A comprehensive review

Inulin as a heterogeneous blend of fructose polymers is diversely found in nature primarily as storage carbohydrates in plants. Besides, inulin is believed to induce certain techno-functional and associated properties in food systems. Inulin owing to its foam forming ability has been successfully used as fat replacer in quite a wide range of products as dairy and baked products. Furthermore, it is known to impart certain nutritional and therapeutic benefits that extend apart to improve health and reduce the risk of many lifestyle related diseases. Additionally, as a functional ingredient, Inulin has been adopted in various efficacy studies involving animal and human studies to function as a prebiotic, in promoting good digestive health, influencing lipid metabolism and has some beneficial roles in ensuring optimum levels of glucose and insulin. This review article is an attempt to present a comprehensive overview on both techno-functional and therapeutic potential of inulin.

Exposure to polycyclic aromatic hydrocarbons and central obesity enhanced risk for diabetes among individuals with poor lung function

Some studies have shown an association between obesity or exposure to polycyclic aromatic hydrocarbons (PAHs) and the risk of diabetes. This study aimed to investigate the interaction of obesity and urinary monohydroxy-PAHs (OH-PAHs) on diabetes. Individuals (n = 2716) were drawn from the baseline survey of the Wuhan-Zhuhai Cohort Study. They completed the physical examination, measurements of lung function, biochemical indices and urinary OH-PAHs levels. Additive effect of obesity and urinary ΣOH-PAHs levels on diabetes was assessed by calculating the relative excess risk due to interaction (RERI) and the attributable proportion (AP) due to interaction. Several urinary OH-PAHs were positively associated with diabetes in individuals with central obesity or normal weight (p < 0.05 for all). Among individuals with poor lung function, the RERI between urinary ΣOH-PAHs and waist circumstance (WC, RERI: 0.866, 95% CI: -0.431, 2.164, p = 0.192) or waist-to-height ratio (WHtR, RERI: 1.091, 95% CI: -0.124, 2.305, p = 0.078) was found; the AP due to the interaction between urinary ΣOH-PAHs and WC or WHtR was 0.383 (95% CI: -0.07, 0.80, p = 0.086) or 0.465 (95% CI: 0.019, 0.912, p = 0.04). The results indicated that central obesity may enhance the effect of exposure to background PAHs on diabetes in individuals with poor lung function.

Effect of styrene exposure on plasma parameters, molecular mechanisms and gene expression in rat model islet cells

Styrene is an aromatic hydrocarbon compound present in the environment and have primary exposure through plastic industry. The current study was designed to evaluate styrene-induced toxicity parameters in rat plasma fasting blood glucose (FBG) level, oral glucose tolerance, insulin secretion, oxidative stress, and inflammatory cytokines in cellular and molecular levels. Styrene was dissolved in corn oil and administered at different doses (250, 500, 1000, 1500, 2000mg/kg/day and control) to each rat, for 42days. In treated groups, styrene significantly increased fasting blood glucose, plasma insulin (p<0.001) and glucose tolerance. Glucose tolerance, insulin resistance and hyperglycemia were found to be the main consequences correlating gene expression of islet cells. Styrene caused a significant enhancement of oxidative stress markers (p<0.001) and inflammatory cytokines in a dose and concentration-dependent manner in plasma (p<0.001). Moreover, the activities of caspase-3 and -9 of the islet cells were significantly up-regulated by this compound at 1500 and 2000mg/kg/day styrene administrated groups (p<0.001). The relative fold change of GLUD1 was downregulated (p<0.05) and upregulated at 1500 and 2000mg/kg, respectively (p<0.01). The relative fold changes of GLUT2 were down regulated at 250 and 1000mg/kg and up regulated in 500, 1500 and 2000mg/kg doses of styrene (p<0.01). The expression level of GCK indicated a significant upregulation at 250mg/kg and downregulation of relative fold changes in the remaining doses of styrene, except for no change at 2000mg/kg of styrene for GCK. Targeting genes (GLUD1, GLUT2 and GCK) of the pancreatic islet cells in styrene exposed groups, disrupted gluconeogenesis, glycogenolysis pathways and insulin secretory functions. The present study illustrated that fasting blood glucose, insulin pathway, oxidative balance, inflammatory cytokines, cell viability and responsible genes of glucose metabolism are susceptible to styrene, which consequently lead to other abnormalities in various organs.