The role of pioglitazone in antioxidant, anti-inflammatory, and insulin sensitivity in a high fat-carbohydrate diet-induced rat model of insulin resistance

Pioglitazone mitigates acetic acid-induced colitis in rats via epigenetic-modulation and antioxidant mechanisms

Ulcerative colitis (UC) is one of the inflammatory bowel diseases characterized by colonic damage. Epigenetic mechanisms are suggested to play a role in the pathogenesis of UC. Pioglitazone has shown promise for the treatment of UC; however, the role of epigenetic pathways in this effect is unclear. The current study aimed to explore the therapeutic and protective effects of pioglitazone against acetic acid-induced colitis (AA-C) in rats and the role of epigenetic modulation and antioxidant mechanisms in this effect. Forty male albino rats were divided into four groups (n = 10/group): control (normal saline), acetic-acid-induced ulcerative colitis (AA-C) (3 days, 2 ml acetic acid 4%), pioglitazone-treated (AA, followed by 3-week oral pioglitazone 25 mg/kg/day), and pioglitazone-protected groups (3-day oral pioglitazone 25 mg/kg/day before AA, continued with AA, and 3 weeks later). After the experiment, the body weight, colon weight-to-length ratio, and colonic tissue were evaluated. The colonic expression of epigenetic markers (DNA methyltransferase- 1 and methylated E-cadherin), oxidative stress marker (malondialdehyde), antioxidant enzyme (superoxide dismutase), and angiotensin-converting enzyme- 2 (ACE- 2) was evaluated. The pioglitazone-protected and treated groups showed significant inhibition of DNA methyltransferase- 1 and methylated E-cadherin with improvement in colonic tissue macroscopic and microscopic signs of inflammation, improved weight, less oxidative stress, and less ACE- 2 expression. These beneficial actions were more pronounced among the pioglitazone-protected group. Pioglitazone could mitigate AA-C in rats by inhibiting epigenetic DNA methyltransferase- 1 and E-cadherin gene methylation. It also inhibits oxidative stress and prevents the overexpression of ACE- 2.

Comprehensive impact of PPARG mutations in familial partial lipodystrophy type 3: Diagnosis, therapeutic strategies

This article reviews a paper in the World Journal of Diabetes. The study uncovers the link between PPARG gene mutations and metabolic disorders, such as insulin resistance, diabetes, and hypertriglyceridemia, and emphasizes the crucial role of genetic testing in precise diagnosis and personalized treatment. This article further points out that in-depth investigation into the clinical heterogeneity of PPARG mutations and their underlying mechanisms can contribute to optimizing management strategies. Meanwhile, the development of more effective targeted therapies and the conduct of extensive genomic research are of great significance for understanding familial partial lipodystrophy type 3 and related metabolic syndromes.

Agomelatine Mitigates Kidney Damage in Obese Insulin-Resistant Rats by Inhibiting Inflammation and Necroptosis via the TNF-α/NF-ĸB/p-RIPK3 Pathway

Obesity is a risk factor for chronic kidney disease. The expansion of adipose tissues in obesity induces insulin resistance and low-grade systemic inflammation, promoting kidney damage. Our previous studies have demonstrated that agomelatine (AGOM) exerts renoprotective effects in experimental models of obesity and insulin resistance through various mechanisms, including the attenuation of ER stress and oxidative stress. This study aimed to further explore the effects of agomelatine on renal inflammation, insulin signaling, and necroptosis in obese, insulin-resistant rats. Obesity was induced in rats with a high-fat diet for 16 weeks, followed by 4 weeks of treatment with 20 mg kg-1 day-1 of AGOM or 10 mg kg-1 day-1 of pioglitazone (PIO). The results showed that insulin resistance was improved after treatment with AGOM and PIO, as demonstrated by the reduction in fasting plasma glucose, insulin, and HOMA-IR. Both treatments restored the levels of renal insulin signaling proteins. Moreover, AGOM inhibited TNFα, TNFR1, NF-ĸB, COX2, and IL1β, which attenuated the necroptosis-related proteins RIPK3 and MLKL. AGOM also prevented kidney DNA fragmentation, as detected by the TUNEL assay. In an obese condition, the level of the tight junction protein claudin-1 (CLDN1) was enhanced after being treated with AGOM. In conclusion, the novel mechanisms associated with AGOM and involved in limiting kidney injury were the inhibition of the TNFα/NF-ĸB/p-RIPK3 pathway and a reduction in inflammation and necroptosis. This suggested that AGOM could be an effective treatment for inhibiting kidney dysfunction in cases of obesity and insulin resistance. These findings open new avenues for the management of renal dysfunction, with implications for personalized medicine.

In Silico and In Vivo Evaluation of Novel 2-Aminobenzothiazole Derivative Compounds as Antidiabetic Agents

Currently, there are several drugs used for the treatment of type 2 diabetes (T2D); however, all of them have adverse effects. Benzothiazoles have a broad spectrum of biological activities such as antidiabetic. This study aimed to evaluate in silico and in vivo two series of 2-aminobenzothiazole derivatives linked to isothioureas (3a-w) or guanidines (4a-z) for the treatment of T2D. The ADMET properties were determined in silico, from which it was possible to select nine compounds (two isothioureas and seven guanidines), and, with molecular docking, it was shown that compounds methyl (E)-N'-(benzo[d]thiazol-2-yl)-N-methylcarbamimidothioate (3b) and 2-(benzo[d]thiazol-2-yl)-1,3-di-tert-butylguanidine (4y) showed a high affinity for PPARγ (ΔG = -7.8 and -8.4 kcal/mol, respectively). In vivo, the LD50 value was estimated in rats based on OECD Guideline 425, being >1750 mg/kg for both compounds. The pharmacological effect of 3b and 4y was evaluated in the T2D rat model, showing that after oral administration in an equimolar ratio to pioglitazone (15 mg/kg) for 4 weeks, both compounds were able to reduce blood glucose levels (<200 mg/dL) and improve the lipid profile. Therefore, 3b and 4y could be used in the future as antidiabetic agents.

Efficacy and Safety of Pioglitazone/Metformin Fixed-Dose Combination Versus Uptitrated Metformin in Patients with Type 2 Diabetes without Adequate Glycemic Control: A Randomized Clinical Trial

INTRODUCTION

We aim to evaluate the efficacy and safety of pioglitazone/metformin fixed-dose combination (FDC) versus uptitrated metformin in patients with type 2 diabetes mellitus (T2DM) without adequate glycemic control.

METHODS

A total of 304 patients were recruited from 15 hospitals in China and randomly assigned (1:1) to the test group (pioglitazone/metformin FDC, 15/500 mg) or the control group (uptitrated metformin, 2000-2500 mg/day). The primary endpoint was the proportion of patients with glycated hemoglobin A1c (HbA1c) ≤ 6.5% and ≤ 7.0% at week 16. The secondary outcomes included the change from baseline in glucose, serum lipids, and liver function. Full analysis set (FAS) and per-protocol set (PPS) were used for analyses.

RESULTS

In the test group, 103 (69.59%) patients reached HbA1c ≤ 7.0% (FAS, P = 0.009), with 68 (45.95%) patients achieved HbA1c ≤ 6.5 (FAS, P = 0.043). More reduction in HbA1c, homeostatic model assessment for insulin resistance, and diastolic pressure was found. Bodyweight, body mass index, and high-density lipoprotein cholesterol increased markedly. The changes of triglycerides, alanine transaminase, aspartate aminotransferase, and high-sensitivity C-reactive protein decreased noticeably. There were no significant differences in rates of adverse events between the two groups.

CONCLUSIONS

Pioglitazone/metformin FDC was superior to uptitrated metformin among patients with T2DM without adequate glycemic control.

TRIAL REGISTRATION NUMBER

This trial is registered with the Chinese Clinical Trial Registry (ChiCTR1900028606).

Pioglitazone as a Possible Treatment for Ataxia-Telangiectasia

Ataxia-telangiectasia (AT) is a rare autosomal recessive disorder characterized by immunodeficiency, progressive cerebellar ataxia, and an increased malignancy risk. Cells derived from individuals with AT show multiple defects, including high oxidant and ionizing radiation sensitivities, poor DNA repair, low iron-sulfur cluster levels, and low reduced glutathione. The clinical course of AT is progressive and unrelenting, with most individuals having a survival time of approximately twenty-five years. Presently, AT has no effective treatments, and most patients receive supportive care only. Recently, pioglitazone, a thiazolidinedione class used to treat type 2 diabetes, has been demonstrated to exert beneficial effects on AT cells and on diabetic individuals with AT. Here, I will discuss the possible molecular mechanisms of pioglitazone's favorable effects on the AT phenotype and why it may have utility in treating some aspects of AT.

Metabolite Diversity and Carbohydrate Distribution in Brassica campestris ssp. chinensis L. Cultivars: A UPLC-MS/MS Approach

Pak choi exhibits a wide range of phenotypic and morphological variations, significantly impacting its carbohydrate composition. This study aimed to analyze these variations by employing UPLC-MS/MS technology on eight biological replicates of seven Pak choi cultivars. The untargeted metabolic analysis identified 513 metabolites, focusing on 16 key carbohydrates, including monosaccharides, disaccharides, and polysaccharides. Monosaccharides were the most prevalent, which were followed by di-, poly-, and oligosaccharides. Suzhouqing had the highest number of differentially accumulated metabolites (DAMs), while Xiangqingcai had the least. Notably, the cultivars Xiangqingcai, Suzhouqing, and Aijiaohuang showed significant metabolite differentiation. The study found 114 metabolites that differed significantly between Suzhouqing and Aijiaohuang, of which 69 were upregulated and 45 were downregulated. In Xiangqingcai and Aijiaohuang, 66 metabolites were upregulated and 49 were downregulated. Between Xiangqingcai and Suzhouqing, 80 metabolites were downregulated and 53 were upregulated. Key carbohydrate digestion and absorption pathways were identified alongside the most enriched flavonoid biosynthesis pathway in Xiangqingcai and Suzhouqing. The findings highlight the considerable carbohydrate variation among Pak choi cultivars, providing valuable insights for targeted carbohydrate extraction and improving nutritional and agricultural practices.

Pioglitazone ameliorates DOX-induced cognitive impairment by mitigating inflammation, oxidative stress, and apoptosis of hippocampal neurons in rats

Doxorubicin (DOX) is broadly used as a medication for cancer treatment. However, DOX has been connected with chemotherapy-related complications, for instance, cognitive impairment (chemobrain). Chemobrain developed in up to 70% of cancer patients; therapeutic is unavailable. This study investigated the preventive effect of pioglitazone (PIO) on neurotoxicity caused by (DOX) in the hippocampus. Forty rats were separated into four groups; control (normal saline 10 ml/kg), DOX (5 mg/kg, intraperitoneally every 3rd day, equivalent to 20 mg/kg cumulative dose), PIO (2 mg/kg in drinking water), and DOX+PIO (DOX, 5 mg/kg, intraperitoneally every 3rd day concurrently PIO, 2 mg/kg in drinking water) and duration of drug treatment lasted for 14 days. The animals were subjected to contextual fear memory tests to characterize the cognitive impairment following DOX treatment. ELISA assessed hippocampal protein expression related to inflammation, oxidative damage, and apoptosis. DOX-treatment produced significant reduction in freezing duration in contextual fear memory tests, which was reversed by PIO co-administration. DOX increased neuroinflammation, oxidative stress, apoptosis, and mitochondrial activity by increasing NF-κB and COX-2 levels, reducing SOD levels, and increasing Bax, caspase-3, and lipid peroxidation. However, DOX did not affect GSH or catalase levels. PIO co-administration reduces NF-κB, COX-2, MDA, Bax, and caspase-3 levels and improves mitochondrial activity and SOD expression. To sum up, DOX therapy accelerates cognitive decline in rats by increasing neuroinflammation, oxidative stress, mitochondrial dysfunction, lipid peroxidation, and apoptosis. PIO is a promising treatment for DOX-induced cognitive impairment.

Exploring Promising Therapies for Non-Alcoholic Fatty Liver Disease: A ClinicalTrials.gov Analysis

Background

Non-alcoholic fatty liver disease (NAFLD) is a common disease and has been increasing in recent years. To date, no FDA-approved drug specifically targets NAFLD.

Methods

The terms "Non-alcoholic Fatty Liver Disease" and "NAFLD" were used in a search of ClinicalTrials.gov on August 24, 2023. Two evaluators independently examined the trials using predetermined eligibility criteria. Studies had to be interventional, NAFLD focused, in Phase IV, and completed to be eligible for this review.

Results

The ClinicalTrials.gov database was searched for trials examining pharmacotherapeutics in NAFLD. The search revealed 1364 trials, with 31 meeting the inclusion criteria. Out of these, 19 were finalized for evaluation. The dominant intervention model was Parallel. The most prevalent studies were in Korea (26.3%) and China (21.1%). The most common intervention was metformin (12.1%), with others like Exenatide and Pioglitazone accounting for 9.1%.

Conclusion

Therapeutics used to manage NAFLD are limited. However, various medications offer potential benefits. Further investigations are definitely warranted.

Therapeutic potential of ginsenoside compound K in managing tenocyte apoptosis and extracellular matrix damage in diabetic tendinopathy

The prevalence of tendinopathy in patients with diabetes is well documented. Despite efforts to improve diabetes management, there is a lack of research on therapeutic agents targeting the core features of tendinopathy, namely, tenocyte apoptosis and extracellular matrix (ECM) damage. In this study, we investigated the potential of ginsenoside compound K (CK), known for its antidiabetic properties, to mitigate tenocyte apoptosis, inflammation, oxidative stress, and the metalloproteinase (MMP) system under hyperglycemic conditions. Our research also aimed to unravel the molecular mechanism underlying the effects of CK. The assessment of apoptosis involved observing intracellular chromatin condensation and measuring caspase 3 activity. To gauge oxidative stress, we examined cellular ROS levels and hydrogen peroxide and malondialdehyde concentrations. Western blotting was employed to determine the expression of various proteins. Our findings indicate that CK treatment effectively countered high glucose-induced apoptosis, inflammation, and oxidative stress in cultured tenocytes. Furthermore, CK normalized the expression of MMP-9, MMP-13, and TIMP-1. Notably, CK treatment boosted the expression of PPARγ and antioxidant enzymes. We conducted small interfering (si) RNA experiments targeting PPARγ, revealing its role in mediating CK's effects on tendinopathy features in hyperglycemic tenocytes. In conclusion, these in vitro results offer valuable insights into the potential therapeutic role of CK in managing tendinopathy among individuals with diabetes. By addressing crucial aspects of tendinopathy, CK presents itself as a promising avenue for future research and treatment development in this domain.

Relationship between TyG index and the degree of coronary artery lesions in patients with H-type hypertension

BACKGROUND

The TyG index, a prominent metric for assessing insulin resistance, has gained traction as a prognostic tool for cardiovascular disease. Nevertheless, the understanding of the prognostic significance of the extent of coronary artery stenosis in individuals afflicted with H-type hypertension remains limited.

METHODS

A retrospective study was conducted at Wuhan Third Hospital, including a cohort of 320 inpatients who were diagnosed with hypertension in combination with coronary artery disease. The study period spanned from January 1, 2021, to February 1, 2023. The study cohort was stratified based on the severity of stenosis into three distinct groups: low stenosis, medium stenosis, and high stenosis, as determined by the Gensini score derived from coronary angiography findings. The present study aimed to investigate the association between the severity of coronary stenosis and the number of lesion branches, utilizing the TyG index as a testing indicator. The predictive ability of TyG for coronary lesion severity was assessed using logistic regression analysis.

RESULTS

The results of our study indicate a positive correlation between elevated levels of TyG and an increased susceptibility to severe stenosis in individuals diagnosed with H-type hypertension. Upon careful consideration of potential confounding variables, it has been observed that the TyG index exhibits a robust association with the likelihood of severe stenosis in individuals with H-type hypertension (odds ratio [OR] = 4000, 95% confidence interval CI 2.411-6.635, p = 0.0001), as well as the prevalence of multivessel disease (OR = 1.862, 95% CI 1.036-3.348, p < 0.0001). The TyG index demonstrated superior predictive ability for severe coronary stenosis in patients with H-type hypertension compared to those without H-type hypertension (area under the curve [AUC] = 0.888, 95% confidence interval CI 0.838-0.939, p < 0.0001, versus AUC = 0.615, 95% CI 0.494-0.737, p < 0.05).

CONCLUSION

The TyG index is an independent risk factor for the degree of coronary stenosis and a better predictor in patients with H-type hypertension combined with coronary artery disease.

The Safety and Efficacy of Combining Saxagliptin and Pioglitazone Therapy in Streptozocin-Induced Diabetic Rats

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a chronic progressive disease due to insulin resistance. Oxidative stress complicates the etiology of T2DM. Saxagliptin is a selective dipeptidyl peptidase-4 (DPP-4) inhibitor, while Pioglitazone is a thiazolidinedione insulin sensitizer. This study aimed to assess the effect of Saxagliptin and Pioglitazone monotherapy and combination therapy on the biochemical and biological parameters in streptozotocin (STZ)-induced diabetic rats.

METHODS

The study included thirty-five male albino rats. Diabetes mellitus was induced by intraperitoneal STZ injection (35 mg/kg). For a 1-month duration, rats were divided into five groups. Glucose homeostasis traits, lipid profiles, kidney functions, liver enzymes, and oxidative stress markers were measured. Gene expression of miRNA-29a, phosphoenolpyruvate carboxykinase (PEPCK), phosphoinositide-3-kinase (PI3K), and interleukin 1 beta (IL-1β) was assessed using qRT-PCR.

RESULTS

At a 1-month treatment duration, combination therapy improves oxidative stress markers more than either drug alone. The combination therapy had significantly higher levels of SOD, catalase, and GSH and lower levels of MDA compared to the monotherapy. Additionally, the diabetic group showed a significant increase in the expression levels of miRNA-29a, PEPCK, and IL-1β and a significant decrease in PI3K compared to the normal control group. However, combination therapy of Saxagliptin and Pioglitazone was more effective than either Saxagliptin or Pioglitazone alone in reversing these results, especially for PEPCK and IL-1β.

CONCLUSIONS

Our findings revealed that combining Saxagliptin and Pioglitazone improves glycemic control and genetic and epigenetic expression profiles, which play an essential regulatory role in normal metabolism.

Restoring autophagic function: a case for type 2 diabetes mellitus drug repurposing in Parkinson's disease

Parkinson's disease (PD) is a predominantly idiopathic pathological condition characterized by protein aggregation phenomena, whose main component is alpha-synuclein. Although the main risk factor is ageing, numerous evidence points to the role of type 2 diabetes mellitus (T2DM) as an etiological factor. Systemic alterations classically associated with T2DM like insulin resistance and hyperglycemia modify biological processes such as autophagy and mitochondrial homeostasis. High glucose levels also compromise protein stability through the formation of advanced glycation end products, promoting protein aggregation processes. The ability of antidiabetic drugs to act on pathways impaired in both T2DM and PD suggests that they may represent a useful tool to counteract the neurodegeneration process. Several clinical studies now in advanced stages are looking for confirmation in this regard.

Lean nonalcoholic fatty liver disease and sarcopenia

Nonalcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases in the world. The risk factor for NAFLD is often considered to be obesity, but it can also occur in people with lean type, which is defined as lean NAFLD. Lean NAFLD is commonly associated with sarcopenia, a progressive loss of muscle quantity and quality. The pathological features of lean NAFLD such as visceral obesity, insulin resistance, and metabolic inflammation are inducers of sarcopenia, whereas loss of muscle mass and function further exacerbates ectopic fat accumulation and lean NAFLD. Therefore, we discussed the association of sarcopenia and lean NAFLD, summarized the underlying pathological mechanisms, and proposed potential strategies to reduce the risks of lean NAFLD and sarcopenia in this review.

Effect of Rosiglitazone, the Peroxisome Proliferator-Activated Receptor (PPAR)-γ Agonist, on Apoptosis, Inflammatory Cytokines and Oxidative Stress in pentylenetetrazole-Induced Seizures in Kindled Mice

A growing body of evidence has shown that seizure can trigger inflammatory cascades through increasing the expression of several inflammatory cytokines. It has been proved that peroxisome proliferator-activated receptor-γ agonists have immunomodulatory, anti-inflammatory, and neuroprotective effects beyond the putative hypoglycemic effects. Thus, we investigated the inhibitory effect of rosiglitazone on the development of pentylenetetrazol (PTZ)-induced kindling via affecting the inflammatory pathway. Male C57BL/6 mice were randomly divided into vehicle group (0.1% DMSO), PTZ-group and rosiglitazone-PTZ-group. Kindling was induced by the administration of PTZ (40 mg/kg, i.p) every other day and mice were observed for 20 min after each PTZ injection. Twenty-four hours after the last dose, animals were euthanized and hippocampus was isolated. The level of Malondialdehyde (MDA), Superoxide Dismutase (SOD), and Catalase (CAT) activity were quantified in hippocampus by biochemical methods. The protein levels of IL-1β, IL-6, IL-10, IFN-γ, TNF-α, caspase-3, iNOS, PPAR-γ, Bcl-2, or Bax factors were measured with western blotting. Also, the quantitative real-time PCR were used to evaluate the mRNA expression of those factors. Pretreatment with rosiglitazone significantly prevented the progression of kindling in comparison with control group. The rosiglitazone significantly decreased the MDA level and increased the CAT, and SOD levels in the rosiglitazone treated mice compared to those in the PTZ group (P < 0.01). Using real-time PCR and Western blotting assay, similar results were obtained. The expression levels of IL-1β, IL-6, IL-10, IFN-γ, TNF-α, Bax or PPAR-γ were significantly changed in the brain. The results of this study suggest that effect of rosiglitazone may be crucial in its ability to protect against the neuronal damage caused by PTZ induced seizure.

Effects of Gold Nanoparticles Functionalized with Cornus mas L. Fruit Extract on the Aorta Wall in Rats with a High-Fat Diet and Experimental-Induced Diabetes Mellitus-An Imaging Study

Diabetes mellitus and high-fat diets trigger the mechanisms that alter the walls of blood vessels. Gold nanoparticles, as new pharmaceutical drug delivery systems, may be used in the treatment of different diseases. In our study, the aorta was investigated via imaging after the oral administration of gold nanoparticles functionalized with bioactive compounds derived from Cornus mas fruit extract (AuNPsCM) in rats with a high-fat diet and diabetes mellitus. Sprague Dawley female rats that received a high-fat diet (HFD) for 8 months were injected with streptozotocin to develop diabetes mellitus (DM). The rats were randomly allocated into five groups and were treated, for one additional month with HFD, with carboxymethylcellulose (CMC), insulin, pioglitazone, AuNPsCM solution or with Cornus mas L. extract solution. The aorta imaging investigation consisted of echography, magnetic resonance imaging and transmission electron microscopy (TEM). Compared to the rats that received only CMC, the oral administration of AuNPsCM produced significant increases in aorta volume and significant decreases in blood flow velocity, with ultrastructural disorganization of the aorta wall. The oral administration of AuNPsCM altered the aorta wall with effects on the blood flow.

Effects of Thyroid Hormones on Lipid Metabolism Pathologies in Non-Alcoholic Fatty Liver Disease

The typical modern lifestyle contributes to the development of many metabolic-related disorders, as exemplified by metabolic syndrome. How to prevent, resolve, or avoid subsequent deterioration of metabolic disturbances and the development of more serious diseases has become an important and much-discussed health issue. Thus, the question of the physiological and pathological roles of thyroid hormones (THs) in metabolism has never gone out of fashion. Although THs influence almost all organs, the liver is one of the most important targets as well as the hub of metabolic homeostasis. When this homeostasis is out of balance, diseases may result. In the current review, we summarize the common features and actions of THs, first focusing on their effects on lipid metabolism in the liver. In the second half of the review, we turn to a consideration of non-alcoholic fatty liver disease (NAFLD), a disease characterized by excessive accumulation of fat in the liver that is independent of heavy alcohol consumption. NAFLD is a growing health problem that currently affects ~25% of the world’s population. Unfortunately, there are currently no approved therapies specific for NAFLD, which, if left uncontrolled, may progress to more serious diseases, such as cirrhosis or liver cancer. This absence of effective treatment can also result in the development of non-alcoholic steatohepatitis (NASH), an aggressive form of NAFLD that is the leading cause of liver transplantation in the United States. Because THs play a clear role in hepatic fat metabolism, their potential application in the prevention and treatment of NAFLD has attracted considerable research attention. Studies that have investigated the use of TH-related compounds in the management of NAFLD are also summarized in the latter part of this review. An important take-home point of this review is that a comprehensive understanding of the physiological and pathological roles of THs in liver fat metabolism is possible, despite the complexities of this regulatory axis—an understanding that has clinical value for the specific management of NAFLD.

Oxidative stress in obesity and insulin resistance

Since obesity is one of the main factors in the development of insulin resistance (IR) and is also associated with increased oxidative stress (OxS) rate, this study aims to review the published literature to collate and provide a comprehensive summary of the studies related to the status of the OxS in the pathogenesis of obesity and related IR. OxS represents an imbalance between the production of reactive oxygen and nitrogen species (RONS) and the capacity of the antioxidant defense system (AOS) to neutralize RONS. A steady-state of RONS level is maintained through endogenous enzymatic and non-enzymatic AOS components. Three crucial enzymes, which suppress the formation of free radicals, are superoxide dismutases, catalases, and glutathione peroxidases. The second line of AOS includes non-enzymatic components such as vitamins C and E, coenzyme Q, and glutathione which neutralizes free radicals by donating electrons to RONS. Emerging evidence suggests that high RONS levels contribute to the progression of OxS in obesity by activating inflammatory pathways and thus leading to the development of pathological states, including IR. In addition, decreased level of AOS components in obesity increases the susceptibility to oxidative tissue damage and further progression of its comorbidities. Increased OxS in accumulated adipose tissue should be an imperative target for developing new therapies in obesity-related IR.

In Vivo and Ex Vivo Evaluation of 1,3-Thiazolidine-2,4-Dione Derivatives as Euglycemic Agents

Thiazolidinediones (TZDs), used to treat type 2 diabetes mellitus, act as full agonists of the peroxisome proliferator-activated receptor gamma. Unfortunately, they produce adverse effects, including weight gain, hepatic toxicity, and heart failure. Our group previously reported the design, synthesis, in silico evaluation, and acute oral toxicity test of two TZD derivatives, compounds 40 (C40) and 81 (C81), characterized as category 5 and 4, respectively, under the Globally Harmonized System. The aim of this study was to determine whether C40, C81, and a new compound, C4, act as euglycemic and antioxidant agents in male Wistar rats with streptozotocin-induced diabetes. The animals were randomly divided into six groups (n = 7): the control, those with diabetes and untreated, and those with diabetes and treated with pioglitazone, C40, C81, or C4 (daily for 21 days). At the end of the experiment, tissue samples were collected to quantify the level of glucose, insulin, triglycerides, total cholesterol, and liver enzymes, as well as enzymatic and nonenzymatic antioxidant activity. C4, without a hypoglycemic effect, displayed the best antioxidant activity. Whereas C81 could only attenuate the elevated level of blood glucose, C40 generated euglycemia by the end of the treatment. All compounds produced a significant decrease in triglycerides.