Cellular Stresses and Stress Responses in the Pathogenesis of Insulin Resistance

Exploring the therapeutic potential of Chinese herbs on comorbid type 2 diabetes mellitus and Parkinson's disease: A mechanistic study

ETHNOPHARMACOLOGICAL RELEVANCE

Type 2 diabetes mellitus (T2DM) and Parkinson's disease (PD) are chronic conditions that affect the aging population, with increasing prevalence globally. The rising prevalence of comorbidity between these conditions, driven by demographic shifts, severely impacts the quality of life of patients, posing a significant burden on healthcare resources. Chinese herbal medicine has been used to treat T2DM and PD for millennia. Pharmacological studies have demonstrated that medicinal herbs effectively lower blood glucose levels and exert neuroprotective effects, suggesting their potential as adjunctive therapy for concurrent management of T2DM and PD.

AIM OF THE STUDY

To elucidate the shared mechanisms underlying T2DM and PD, particularly focusing on the potential mechanisms by which medicinal herbs (including herbal formulas, single herbs, and active compounds) may treat these diseases, to provide valuable insights for developing therapeutics targeting comorbid T2DM and PD.

MATERIALS AND METHODS

Studies exploring the mechanisms underlying T2DM and PD, as well as the treatment of these conditions with medicinal herbs, were extracted from several electronic databases, including PubMed, Web of Science, Google Scholar, and China National Knowledge Infrastructure (CNKI).

RESULTS

Numerous studies have shown that inflammation, oxidative stress, insulin resistance, impaired autophagy, gut microbiota dysbiosis, and ferroptosis are shared mechanisms underlying T2DM and PD mediated through the NLRP3 inflammasome, NF-κB, MAPK, Keap1/Nrf2/ARE, PI3K/AKT, AMPK/SIRT1, and System XC--GSH-GPX4 signaling pathways. Thirty-four medicinal herbs, including 2 herbal formulas, 4 single herbs, and 28 active compounds, have been reported to potentially exert anti-T2DM and anti-PD effects by targeting these shared mechanisms.

CONCLUSIONS

Traditional Chinese medicine effectively combats T2DM and PD through shared pathological mechanisms, highlighting their potential for application in treating these comorbid conditions.

The protective effects of fisetin in metabolic disorders: a focus on oxidative stress and associated events

Abstract

Metabolic syndrome is increasingly recognized as a significant precursor to various chronic diseases, contributing to a growing public health concern. Its complex pathogenesis involves multiple interrelated mechanisms, with oxidative stress identified as a cornerstone that exacerbates other pathogenic pathways. This study elucidates the molecular mechanisms by which oxidative stress intensifies metabolic disturbances, particularly insulin resistance. Some recent research has focused on fisetin, a natural product known for its potential benefits in diabetes and its associated microvascular and macrovascular complications. This paper compiles a comprehensive collection of findings by reviewing studies conducted over the past decade, detailing dosages, investigated markers, and their respective outcomes. Notably, a recurrent finding was fisetin's ability to enhance Nrf2, a principal regulator of antioxidant defense, in both metabolic and non-metabolic diseases. Furthermore, intriguing results suggest that the effects of Nrf2 extend beyond oxidative stress modulation, demonstrating favorable impacts on tissue-specific functions in metabolic regulation. This highlights fisetin not only as an antioxidant but also as a potential therapeutic agent for improving metabolic health and mitigating the effects of metabolic syndrome. In conclusion, fisetin can enhance the body's antioxidant defenses by modulating the Nrf2 pathway while also improving metabolic health through its effects on inflammation, cell survival, and energy metabolism, offering a comprehensive approach to managing metabolic disorders.

Graphical Abstract

Research progress on the association of insulin resistance with type 2 diabetes mellitus and Alzheimer's disease

Type 2 diabetes mellitus (T2DM) is a metabolic disorder that is characterized by insulin resistance and hyperglycemia. It is also known to be a risk factor for Alzheimer's disease (AD). Insulin plays a crucial role in regulating the body's metabolism and is responsible for activating the Phosphoinotide-3-Kinase (PI3K)/Protein Kinase B (Akt) signaling pathway. This pathway is activated when insulin binds to the insulin receptor on nerve cells, and it helps regulate the metabolism of glucose and lipids. Dysfunction in the insulin signaling pathway can lead to a decrease in brain insulin levels and insulin sensitivity, thereby inducing disruptions in insulin signal transduction and leading to disorders in brain energy metabolism. Moreover, these dysfunctions also contribute to the accumulation of β-amyloid (Aβ) deposition and the hyperphosphorylation of Tau protein, both of which are characteristic features of AD. Therefore, this article focuses on insulin resistance to reveal the complex mechanism between brain insulin resistance and AD occurrence in T2DM. On this basis, this article further summarizes the biological effects and mechanisms of antidiabetic drugs on the two diseases, aiming to provide new ideas for the discovery of drugs for the treatment of T2DM combined with AD.

Relationship Between Serum Levels of Oxidized Lipoproteins, Circulating Levels of Myeloperoxidase and Paraoxonase 1, and Diet in Young Subjects with Insulin Resistance

Oxidized low-density lipoproteins (ox-LDLs) are involved in atherosclerotic plaque formation and progression and have been linked to insulin resistance (IR). Myeloperoxidase is a potent oxidant of lipoproteins related to atherogenic risk. High-density lipoproteins (HDLs) are considered antioxidants due to their association with paraoxonase 1 (PON1). However, HDL can also be oxidized (ox-HDL), and its relationship with IR has not been described. This study evaluated the relationship between circulating levels of myeloperoxidase and paraoxonase 1, diet, and serum levels of ox-LDL and ox-HDL in young people with IR. This cross-sectional study examined 136 young subjects (67 and 69 with and without insulin resistance, respectively). Serum levels of ox-LDL, ox-HDL, myeloperoxidase, and PON1 were quantified using an enzyme-linked immunosorbent assay. The nutritional dietary content of the foods was determined with a food frequency questionnaire, which was analyzed with Nutrimind 2013 software. Serum ox-HDL levels were higher in young subjects without IR than those with IR (p = 0.031). Women with IR presented increased ox-LDL levels compared with women without IR (p = 0.012) and men with IR (p < 0.001). In the IR group, serum ox-LDL levels were negatively correlated with total cholesterol, triglycerides, and LDL-C, whereas the correlation was positive in the insulin-sensitive group. Consumption of vitamins B1 and B2 was related to increased HDL-C levels, while higher ox-LDL levels were related to vitamin K intake. In addition, low energy consumption and phosphorus increased PON1 levels. The results suggest that insulin resistance in young women may promote lipoprotein oxidation, and the intake of B complex vitamins may have an antiatherogenic effect.

The triglyceride glucose related index is an indicator of Sarcopenia

The triglyceride glucose (TyG) related index, a metric used to evaluate assessing insulin resistance (IR), has received limited attention in its association with sarcopenia. Our study aims to explore the predictive potential of the TyG index for sarcopenia. This study utilized data from the China Health and Retirement Longitudinal Study, a nationally representative, community-based cohort study, including a sample size of 10,537 participants aged 45 years and older. Associations between TyG related index and sacopenia was explored using multivariate logistic regression. Analysis of the predictive value of TyG related index for sarcopenia using receiver-operating characteristic curve (ROC). We evaluated the correlation between the TyG related index and the risk of sarcopenia using Cox proportional hazards models. Additionally, we utilized restricted cubic spline (RCS) regression analyses to explore the connections between the TyG-related index and sarcopenia. Logistic regression analysis showed an association between TyG (OR 0.961[0.955,0.968], P < 0.001), TyG-body mass index (TyG-BMI) (OR 0.872[0.867,0.878], P < 0.001), TyG- waist circumference (TyG-WC) (OR 0.896[0.890,0.902], P < 0.001) and sarcopenia. The results of the ROC analysis indicated that the area under the curve values for TyG, TyG-BMI, and TyG-WC were 0.659, 0.903, and 0.819, respectively. Compared to those without sarcopenia, patients with sarcopenia had a 37.7% (HR 0.623[0.502,0.774], P < 0.001), 4.8% (HR 0.952[0.947,0.958], P < 0.001), and 0.4% (HR 0.996[0.995,0.996], P < 0.001) lower risk with increasing TyG, TyG-BMI, and TyG-WC, respectively. RCS results show nonlinear relationship between TyG-BMI (P < 0.001) and TyG-WC (P < 0.001) and risk of sarcopenia. We observed a correlation between the TyG-related index and sarcopenia, with the TyG-BMI index demonstrating strong predictive capability for sarcopenia.

Role of Akkermansia muciniphila in insulin resistance

Insulin resistance (IR) is a pathogenic factor in numerous metabolic diseases. The gut microbiota plays a crucial role in maintaining the function of the intestinal barrier and overall human health, thereby influencing IR. Dysbiosis of the gut microbiota can contribute to the development of IR. Therefore, it is essential to maintain a balanced and diverse gut microbiota for optimal health. Akkermansia muciniphila, a widely present microorganism in the human intestine, has been shown to regulate gastrointestinal mucosal barrier integrity, reduce endotoxin penetration, decrease systemic inflammation levels, and improve insulin sensitivity. Reduced abundance of A. muciniphila is associated with an increased risk of IR and other metabolic diseases, highlighting its correlation with IR. Understanding the role and regulatory mechanism of A. muciniphila is crucial for comprehending IR pathogenesis and developing novel strategies for preventing and treating related metabolic disorders. Individual variations may exist in both the gut microbiota composition and its impact on IR among different individuals. Further investigation into individual differences between A. muciniphila and IR will facilitate advancements in personalized medicine by promoting tailored interventions based on the gut microbiota composition, which is a potential future direction that would optimize insulin sensitivity while preventing metabolic disease occurrence. In this review, we describe the physiological characteristics of A. muciniphila, emphasize its roles in underlying mechanisms contributing to IR pathology, and summarize how alterations in its abundance affect IR development, thereby providing valuable insights for further research on A. muciniphila, as well as new drug development targeting diabetes.

Allantoin reduces glucotoxicity and lipotoxicity in a type 2 diabetes rat model by modulating the PI3K and MAPK signaling pathways

Objective

The current study aimed to investigate the potential therapeutic impact of allantoin on diabetes produced by a high-fat diet (HFD) and streptozotocin (STZ) in rats.

Subjects and methods

Male Sprague-Dawley rats were fed a high-fat diet to induce insulin resistance, followed by streptozotocin injection to induce diabetes. The effect of oral treatment of allantoin (200, 400 and 800 mg/kg/day) for 8 weeks was evaluated by calculating the alteration in metabolic parameters, biochemical indicators, the oral glucose tolerance tests (OGTT) and hyperinsulinemic-euglycemic clamp tests were performed. Histopathological studies were performed in the liver, kidney and pancreas. Next, the expressions of the MAPK and insulin signaling pathway were measured by Western blot analysis to elucidate the potential mechanism underlying these antidiabetic activities.

Results

The administration of allantoin resulted in a significant decrease in fasting blood glucose (FBG) levels, glycogen levels, and glycosylated hemoglobin levels in diabetic rats. Additionally, allantoin therapy led to a dose-dependent increase in body weight growth and serum insulin levels. In addition, the administration of allantoin resulted in a considerable reduction in lipid profile levels and amelioration of histological alterations in rats with diabetes. The administration of allantoin to diabetic rats resulted in a notable decrease in Malondialdehyde (MDA) levels, accompanied by an increase in the activity of antioxidant enzymes in the serum, liver, and kidney. The findings of oral glucose tolerance and hyperinsulinemic-euglycemic clamp tests demonstrated a significant rise in insulin resistance following the administration of allantoin. The upregulation of IRS-2/PI3K/p-Akt/GLUT expression by allantoin suggests a mechanistic relationship between the PI3K/Akt signaling pathway and the antihyperglycemic activity of allantoin. Furthermore, it resulted in a reduction in the levels of TGF-β1/p38MAPK/Caspase-3 expression in the aforementioned rat tissues affected by diabetes.

Conclusions

This study implies that allantoin treats type 2 diabetes by activating PI3K. Additionally, it reduces liver, kidney, and pancreatic apoptosis and inflammation-induced insulin resistance.re.

mTOR Dysregulation, Insulin Resistance, and Hypertension

Worldwide, diabetes mellitus (DM) and cardiovascular diseases (CVDs) represent serious health problems associated with unhealthy diet and sedentarism. Metabolic syndrome (MetS) is characterized by obesity, dyslipidemia, hyperglycemia, insulin resistance (IR) and hypertension. The mammalian target of rapamycin (mTOR) is a serine/threonine kinase with key roles in glucose and lipid metabolism, cell growth, survival and proliferation. mTOR hyperactivation disturbs glucose metabolism, leading to hyperglycemia and further to IR, with a higher incidence in the Western population. Metformin is one of the most used hypoglycemic drugs, with anti-inflammatory, antioxidant and antitumoral properties, having also the capacity to inhibit mTOR. mTOR inhibitors such as rapamycin and its analogs everolimus and temsirolimus block mTOR activity, decrease the levels of glucose and triglycerides, and reduce body weight. The link between mTOR dysregulation, IR, hypertension and mTOR inhibitors has not been fully described. Therefore, the main aim of this narrative review is to present the mechanism by which nutrients, proinflammatory cytokines, increased salt intake and renin-angiotensin-aldosterone system (RAAS) dysregulation induce mTOR overactivation, associated further with IR and hypertension development, and also mTOR inhibitors with higher potential to block the activity of this protein kinase.

Establish a noninvasive model to screen metabolic dysfunction-associated steatotic liver disease in children aged 6-14 years in China and its applications in high-obesity-risk countries and regions

Background

The prevalence of metabolic-associated steatotic liver disease (MASLD) is rising precipitously among children, particularly in regions or countries burdened with high prevalence of obesity. However, identifying those at high risk remains a significant challenge, as the majority do not exhibit distinct symptoms of MASLD. There is an urgent need for a widely accepted non-invasive predictor to facilitate early disease diagnosis and management of the disease. Our study aims to 1) evaluate and compare existing predictors of MASLD, and 2) develop a practical screening strategy for children, tailored to local prevalence of obesity.

Methods

We utilized a school-based cross-sectional survey in Beijing as the training dataset to establish predictive models for screening MASLD in children. An independent school-based study in Ningbo was used to validate the models. We selected the optimal non-invasive MASLD predictor by comparing logistic regression model, random forest model, decision tree model, and support vector machine model using both the Beijing and Ningbo datasets. This was followed by serial testing using the best performance index we identified and indices from previous studies. Finally, we calculated the potential MASLD screening recommendation categories and corresponding profits based on national and subnational obesity prevalence, and applied those three categories to 200 countries according to their obesity prevalence from 1990 to 2022.

Findings

A total of 1018 children were included (NBeijing = 596, NNingbo = 422). The logistic regression model demonstrated the best performance, identifying the waist-to-height ratio (WHtR, cutoff value ≥0.48) as the optimal noninvasive index for predicting MASLD, with strong performance in both training and validation set. Additionally, the combination of WHtR and lipid accumulation product (LAP) was selected as an optimal serial test to improve the positive predictive value, with a LAP cutoff value of ≥668.22 cm × mg/dL. Based on the obesity prevalence among 30 provinces, three MASLD screening recommendations were proposed: 1) "Population-screening-recommended": For regions with an obesity prevalence ≥12.0%, where MASLD prevalence ranged from 5.0% to 21.5%; 2) "Resources-permitted": For regions with an obesity prevalence between 8.4% and 12.0%, where MASLD prevalence ranged from 2.3% to 4.4%; 3) "Population-screening-not-recommended": For regions with an obesity prevalence <8.4%, where MASLD prevalence is difficult to detect using our tool. Using our proposed cutoff for screening MASLD, the number of countries classified into the "Population-screening-recommended" and "Resources-permitted" categories increased from one and 11 in 1990 to 95 and 28 in 2022, respectively.

Interpretation

WHtR might serve as a practical and accessible index for predicting pediatric MASLD. A WHtR value ≥0.48 could facilitate early identification and management of MASLD in areas with obesity prevalence ≥12.0%. Furthermore, combining WHtR ≥0.48 with LAP ≥668.22 cm × mg/dL is recommended for individual MASLD screening. Moreover, linking these measures with population obesity prevalence not only helps estimate MASLD prevalence but also indicates potential screening profits in regions at varying levels of obesity risk.

Funding

This study was supported by grants from Capital's Funds for Health Improvement and Research (Grant No. 2022-1G-4251), National Natural Science Foundation of China (Grant No. 82273654), Major Science and Technology Projects for Health of Zhejiang Province (Grant No. WKJ-ZJ-2216), Cyrus Tang Foundation for Young Scholar 2022 (2022-B126) and Sino-German Mobility Programme (M-0015).

Recent advances in the effect of adipose tissue inflammation on insulin resistance

Obesity is one of the major risk factors for diabetes. Excessive accumulation of fat leads to inflammation of adipose tissue, which can increase the risk of developing diabetes. Obesity-related chronic inflammation can result in anomalies in glucose-lipid metabolism and insulin resistance, and it is a major cause of β-cell dysfunction in diabetes mellitus. Thus, a long-term tissue inflammatory response is crucial for metabolic diseases, particularly type 2 diabetes. Chronic inflammation associated with obesity increases oxidative stress, secretes inflammatory factors, modifies endocrine variables, and interferes with insulin signalling pathways, all of which contribute to insulin resistance and glucose tolerance. Insulin resistance and diabetes are ultimately caused by chronic inflammation in the stomach, pancreas, liver, muscle, and fat tissues. In this article, we systematically summarize the latest research progress on the mechanisms of adipose tissue inflammation and insulin resistance, as well as the mechanisms of cross-talk between adipose tissue inflammation and insulin resistance, with a view to providing some meaningful therapeutic strategies for the treatment of insulin resistance by controlling adipose tissue inflammation.

Insulin resistance as the molecular link between diabetes and Alzheimer's disease

Diabetes mellitus (DM) and Alzheimer's disease (AD) are two major health concerns that have seen a rising prevalence worldwide. Recent studies have indicated a possible link between DM and an increased risk of developing AD. Insulin, while primarily known for its role in regulating blood sugar, also plays a vital role in protecting brain functions. Insulin resistance (IR), especially prevalent in type 2 diabetes, is believed to play a significant role in AD's development. When insulin signalling becomes dysfunctional, it can negatively affect various brain functions, making individuals more susceptible to AD's defining features, such as the buildup of beta-amyloid plaques and tau protein tangles. Emerging research suggests that addressing insulin-related issues might help reduce or even reverse the brain changes linked to AD. This review aims to explore the rela-tionship between DM and AD, with a focus on the role of IR. It also explores the molecular mechanisms by which IR might lead to brain changes and assesses current treatments that target IR. Understanding IR's role in the connection between DM and AD offers new possibilities for treatments and highlights the importance of continued research in this interdisciplinary field.

Adipose-derived extracellular vesicles - a novel cross-talk mechanism in insulin resistance, non-alcoholic fatty liver disease, and polycystic ovary syndrome

Obesity is the best described risk factor for the development of non-alcoholic fatty liver disease (NAFLD)/metabolic dysfunction associated steatotic liver disease (MASLD) and polycystic ovary syndrome (PCOS) while the major pathogenic mechanism linking these entities is insulin resistance (IR). IR is primarily caused by increased secretion of proinflammatory cytokines, adipokines, and lipids from visceral adipose tissue. Increased fatty acid mobilization results in ectopic fat deposition in the liver which causes endoplasmic reticulum stress, mitochondrial dysfunction, and oxidative stress resulting in increased cytokine production and subsequent inflammation. Similarly, IR with hyperinsulinemia cause hyperandrogenism, the hallmark of PCOS, and inflammation in the ovaries. Proinflammatory cytokines from both liver and ovaries aggravate IR thus providing a complex interaction between adipose tissue, liver, and ovaries in inducing metabolic abnormalities in obese subjects. Although many pathogenic mechanisms of IR, NAFLD/MASLD, and PCOS are known, there is still no effective therapy for these entities suggesting the need for further evaluation of their pathogenesis. Extracellular vesicles (EVs) represent a novel cross-talk mechanism between organs and include membrane-bound vesicles containing proteins, lipids, and nucleic acids that may change the phenotype and function of target cells. Adipose tissue releases EVs that promote IR, the development of all stages of NAFLD/MASLD and PCOS, while mesenchymal stem cell-derived AVs may alleviate metabolic abnormalities and may represent a novel therapeutic device in NAFLD/MASLD, and PCOS. The purpose of this review is to summarize the current knowledge on the role of adipose tissue-derived EVs in the pathogenesis of IR, NAFLD/MASLD, and PCOS.

J-shaped association of the triglyceride glucose-body mass index with new-onset diabetes

The triglyceride glucose-body mass index (TyG-BMI) is a convenient and clinically significant indicator of insulin resistance. This study aims to investigate the correlation between TyG-BMI and the onset of new-onset diabetes and determine an optimal reflection point for TyG-BMI. An analysis was conducted on 1917 participants from the risk evaluation of cancers in Chinese diabetic individuals: a lONgitudinal (REACTION) study. Participants were categorized based on their TyG-BMI, and the relationship between TyG-BMI and the incidence of new-onset diabetes was explored through logistic regression models, smoothed curve fitting with restricted cubic spline, and a two-piecewise logistic regression model. The mean age of the participants was 57.60 ± 8.89 years, with 66.5% being females. The mean TyG-BMI was 223.3 ± 32.8. Ultimately, 137 individuals (7.1%) progressed to diabetes after three years. After adjusting for covariates, TyG-BMI exhibited a positive correlation with new-onset diabetes (odd ratios (OR) for each standard deviation increase = 1.330, 95% CI 1.110-1.595). The relationship between TyG-BMI and new-onset diabetes was non-linear, with a inflcetion point at 202.9. This study reveals a positive non-linear relationship between TyG-BMI and the risk of new-onset diabetes in Chinese middle-aged and elderly individuals. When TyG-BMI exceeds 202.9, there is a significantly heightened risk of new-onset diabetes. These findings offer valuable insights for preventing new-onset diabetes.

Oxidative Stress, Endothelial Dysfunction, and N-Acetylcysteine in Type 2 Diabetes Mellitus

Significance: Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality globally. Endothelial dysfunction is closely associated with the development and progression of CVDs. Patients with diabetes mellitus (DM) especially type 2 DM (T2DM) exhibit a significant endothelial cell (EC) dysfunction with substantially increased risk for CVDs. Recent Advances: Excessive reactive oxygen species (ROS) and oxidative stress are important contributing factors to EC dysfunction and subsequent CVDs. ROS production is significantly increased in DM and is critically involved in the development of endothelial dysfunction in diabetic patients. In this review, efforts are made to discuss the role of excessive ROS and oxidative stress in the pathogenesis of endothelial dysfunction and the mechanisms for excessive ROS production and oxidative stress in T2DM. Critical Issues: Although studies with diabetic animal models have shown that targeting ROS with traditional antioxidant vitamins C and E or other antioxidant supplements provides promising beneficial effects on endothelial function, the cardiovascular outcomes of clinical studies with these antioxidant supplements have been inconsistent in diabetic patients. Future Directions: Preclinical and limited clinical data suggest that N-acetylcysteine (NAC) treatment may improve endothelial function in diabetic patients. However, well-designed clinical studies are needed to determine if NAC supplementation would effectively preserve endothelial function and improve the clinical outcomes of diabetic patients with reduced cardiovascular morbidity and mortality. With better understanding on the mechanisms of ROS generation and ROS-mediated endothelial damages/dysfunction, it is anticipated that new selective ROS-modulating agents and effective personalized strategies will be developed for the management of endothelial dysfunction in DM.

Obesity Is Associated with Oxidative Stress Markers and Antioxidant Enzyme Activity in Mexican Children

The relationship between metabolic disorders and oxidative stress is still controversial in the child population. The present cross-sectional study aimed to analyze the associations between obesity, cardiometabolic traits, serum level of carbonylated proteins (CPs), malondialdehyde (MDA), and the enzyme activity of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in children from Mexico City (normal weight: 120; obesity: 81). Obesity resulted in being positively associated with CAT (β = 0.05 ± 0.01, p = 5.0 × 10-3) and GPx (β = 0.13 ± 0.01, p = 3.7 × 10-19) enzyme activity. A significant interaction between obesity and sex was observed in MDA and SOD enzymatic activity (PMDA = 0.03; PSOD = 0.04). The associations between obesity, MDA level, and SOD enzyme activity were only significant in boys (boys: PMDA = 3.0 × 10-3; PSOD = 7.0 × 10-3; girls: p ≥ 0.79). In both children with normal weight and those with obesity, CP levels were positively associated with SOD enzyme activity (PNormal-weight = 2.2 × 10-3; PObesity = 0.03). In conclusion, in Mexican children, obesity is positively associated with CAT and GPx enzyme activity, and its associations with MDA levels and SOD enzyme activity are sex-specific. Therefore, CP level is positively related to SOD enzyme activity independently of body weight.

Metabolic Alteration Bridging the Prediabetic State and Colorectal Cancer

Prediabetes and colorectal cancer (CRC) represent compelling health burdens responsible for high mortality and morbidity rates, sharing several modifiable risk factors. It has been hypothesized that metabolic abnormalities linking prediabetes and CRC are hyperglycemia, hyperinsulinemia, and adipokines imbalance. The chronic stimulation related to these metabolic signatures can favor CRC onset and development, as well as negatively influence CRC prognosis. To date, the growing burden of prediabetes and CRC has generated a global interest in defining their epidemiological and molecular relationships. Therefore, a deeper knowledge of the metabolic impairment determinants is compelling to identify the pathological mechanisms promoting the onset of prediabetes and CRC. In this scenario, this review aims to provide a comprehensive overview on the metabolic alterations of prediabetes and CRC as well as an overview of recent preventive and therapeutic approaches for both diseases, focusing on the role of the metabolic state as a pivotal contributor to consider for the development of future preventive and therapeutic strategies.

Predictive value of insulin resistance surrogates for the development of diabetes in individuals with baseline normoglycemia: findings from two independent cohort studies in China and Japan

BACKGROUND

Insulin resistance (IR) plays a crucial role in the occurrence and progression of diabetes. This study aimed to evaluate and compare the predictive value of four IR surrogates, including the triglycerides glucose (TyG) index, TyG and body mass index (TyG-BMI), triglycerides/high-density lipoprotein cholesterol (TG/HDL-C) ratio, and the metabolic score for IR (MetS-IR) for diabetes in two large cohorts.

METHODS

A total of 116,661 adult participants from the China Rich Healthcare Group and 15,464 adult participants from the Japanese NAGALA cohort were included in the study. Multivariable Cox proportional hazards models were used to assess the standardized hazard ratio (HR) of the TyG index, TyG-BMI, TG/HDL-C ratio, and MetS-IR directly associated with diabetes. Receiver operating characteristic (ROC) curve and time-dependent ROC curve analysis were performed to evaluate and compare the predictive value of the four IR surrogates for diabetes.

RESULTS

In the two independent cohorts, the average follow-up time was 3.1 years in the China cohort, with 2681(2.30%) incident cases of diabetes recorded, and 6.13 years in the Japan cohort, with 373 incident cases (2.41%) of diabetes recorded. After adjusting for potential confounding factors, we found that among the four IR surrogates, TyG-BMI and MetS-IR showed stronger associations with diabetes. The stronger associations persisted even after further stratification by age, sex, hypertension, and obese subgroups. In terms of diabetes prediction, based on ROC analysis, TyG-BMI demonstrated the highest predictive accuracy for diabetes in the Chinese population, while both TyG-BMI and MetS-IR showed the highest predictive accuracy in the Japanese population. The results of further subgroup ROC analysis confirmed the robustness of these findings. Furthermore, the time-dependent ROC results indicated that among the four IR surrogates, MetS-IR exhibited the highest accuracy in predicting future diabetes at various time intervals in the Japanese population.

CONCLUSION

Our findings suggest that evaluating TyG-BMI and MetS-IR as IR surrogates may be the most useful for predicting diabetes events and assessing the risk of developing diabetes in East Asian populations.

Gallic Acid-Based Hydrogels for Phloretin Intestinal Release: A Promising Strategy to Reduce Oxidative Stress in Chronic Diabetes

Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia caused by abnormalities in insulin secretion and/or action. In patients with diabetes, complications such as blindness, delayed wound healing, erectile dysfunction, renal failure, heart disease, etc., are generally related to an increase in ROS levels which, when activated, trigger hyperglycemia-induced lesions, inflammation and insulin resistance. In fact, extensive cell damage and death occurs mainly due to the effect that ROS exerts at the level of cellular constituents, causing the deterioration of DNA and peroxidation of proteins and lipids. Furthermore, elevated levels of reactive oxygen species (ROS) and an imbalance of redox levels in diabetic patients produce insulin resistance. These destructive effects can be controlled by the defense network of antioxidants of natural origin such as phloretin and gallic acid. For this reason, the objective of this work was to create a nanocarrier (hydrogel) based on gallic acid containing phloretin to increase the antioxidant effect of the two substances which function as fundamental for reducing the mechanisms linked to oxidative stress in patients suffering from chronic diabetes. Furthermore, since the bioavailability problems of phloretin at the intestinal level are known, this carrier could facilitate its release and absorption. The obtained hydrogel was characterized using Fourier transform infrared spectroscopy (FT-IR). Its degree of swelling (a%) and phloretin release were tested under pH conditions simulating the gastric and intestinal environment (1.2, 6.8 and 7.4). The antioxidant activity, inhibiting lipid peroxidation in rat liver microsomal membranes induced in vitro by a free radical source, was evaluated for four hours. All results showed that gallate hydrogel could be applied for releasing intestinal phloretin and reducing the ROS levels.

SREBPs as the potential target for solving the polypharmacy dilemma

The phenomenon of polypharmacy is a common occurrence among older people with multiple health conditions due to the rapid increase in population aging and the popularization of clinical guidelines. The prevalence of metabolic syndrome is growing quickly, representing a serious threat to both the public and the worldwide healthcare systems. In addition, it enhances the risk of cardiovascular disease as well as mortality and morbidity. Sterol regulatory element binding proteins (SREBPs) are basic helix-loop-helix leucine zipper transcription factors that transcriptionally modulate genes that regulate lipid biosynthesis and uptake, thereby serving an essential role in biological systems regulation. In this article, we have described the structure of SREBPs and explored their activation and regulation of signals. We also reveal that SREBPs are intricately involved in the modulation of metabolic diseases and thus have tremendous potential as the novel target for single-drug therapy for multiple diseases.

Dioscin: Therapeutic potential for diabetes and complications

Diabetes mellitus is a widespread metabolic disorder with increasing incidence worldwide, posing a considerable threat to human health because of its complications. Therefore, cost-effective antidiabetic drugs with minimal side effects are urgently needed. Dioscin, a naturally occurring compound, helps to reduce the complications of diabetes mellitus by regulating glucose and lipid metabolism, protecting islet β cells, improving insulin resistance, and inhibiting oxidative stress and inflammatory response. Plant-derived dioscin reduces the risk of toxicity and side effects associated with chemically synthesized drugs. It is a promising option for treating diabetes mellitus because of its preventive and therapeutic effects, which may be attributed to a variety of underlying mechanisms. However, data compiled by current studies are preliminary. Information about the molecular mechanism of dioscin remains limited, and no high-quality human experiments and clinical trials for testing its safety and efficacy have been conducted. As a resource for research in this area, this review is expected to provide a systematic framework for the application of dioscin in the treatment of diabetes mellitus and its complications.

Gut Microbiota and Insulin Resistance: Understanding the Mechanism of Better Treatment of Type 2 Diabetes Mellitus

Gut microbiota refers to the population of trillions of microorganisms present in the human intestine. The gut microbiota in the gastrointestinal system is important for an individual's good health and well-being. The possibility of an intrauterine colonization of the placenta further suggests that the fetal environment before birth may also affect early microbiome development. Various factors influence the gut microbiota. Dysbiosis of microbiota may be associated with various diseases. Insulin regulates blood glucose levels, and disruption of the insulin signaling pathway results in insulin resistance. Insulin resistance or hyperinsulinemia is a pathological state in which the insulin-responsive cells have a diminished response to the hormone compared to normal physiological responses, resulting in reduced glucose uptake by the tissue cells. Insulin resistance is an important cause of type 2 diabetes mellitus. While there are various factors responsible for the etiology of insulin resistance, dysbiosis of gut microbiota may be an important contributing cause for metabolic disturbances. We discuss the mechanisms in skeletal muscles, adipose tissue, liver, and intestine by which insulin resistance can occur due to gut microbiota's metabolites. A better understanding of gut microbiota may help in the effective treatment of type 2 diabetes mellitus and metabolic syndrome.

NADPH Dynamics: Linking Insulin Resistance and β-Cells Ferroptosis in Diabetes Mellitus

This review offers an in-depth exploration of Nicotinamide Adenine Dinucleotide Phosphate (NADPH) in metabolic health. It delves into how NADPH affects insulin secretion, influences insulin resistance, and plays a role in ferroptosis. NADPH, a critical cofactor in cellular antioxidant systems and lipid synthesis, plays a central role in maintaining metabolic homeostasis. In adipocytes and skeletal muscle, NADPH influences the pathophysiology of insulin resistance, a hallmark of metabolic disorders such as type 2 diabetes and obesity. The review explores the mechanisms by which NADPH contributes to or mitigates insulin resistance, including its role in lipid and reactive oxygen species (ROS) metabolism. Parallelly, the paper investigates the dual nature of NADPH in the context of pancreatic β-cell health, particularly in its relation to ferroptosis, an iron-dependent form of programmed cell death. While NADPH's antioxidative properties are crucial for preventing oxidative damage in β-cells, its involvement in lipid metabolism can potentiate ferroptotic pathways under certain pathological conditions. This complex relationship underscores the delicate balance of NADPH homeostasis in pancreatic health and diabetes pathogenesis. By integrating findings from recent studies, this review aims to illuminate the nuanced roles of NADPH in different tissues and its potential as a therapeutic target. Understanding these dynamics offers vital insights into the development of more effective strategies for managing insulin resistance and preserving pancreatic β-cell function, thereby advancing the treatment of metabolic diseases.

Emerging therapeutic options in the management of diabetes: recent trends, challenges and future directions

Diabetes is a serious health issue that causes a progressive dysregulation of carbohydrate metabolism due to insufficient insulin hormone, leading to consistently high blood glucose levels. According to the epidemiological data, the prevalence of diabetes has been increasing globally, affecting millions of individuals. It is a long-term condition that increases the risk of various diseases caused by damage to small and large blood vessels. There are two main subtypes of diabetes: type 1 and type 2, with type 2 being the most prevalent. Genetic and molecular studies have identified several genetic variants and metabolic pathways that contribute to the development and progression of diabetes. Current treatments include gene therapy, stem cell therapy, statin therapy, and other drugs. Moreover, recent advancements in therapeutics have also focused on developing novel drugs targeting these pathways, including incretin mimetics, SGLT2 inhibitors, and GLP-1 receptor agonists, which have shown promising results in improving glycemic control and reducing the risk of complications. However, these treatments are often expensive, inaccessible to patients in underdeveloped countries, and can have severe side effects. Peptides, such as glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), are being explored as a potential therapy for diabetes. These peptides are postprandial glucose-dependent pancreatic beta-cell insulin secretagogues and have received much attention as a possible treatment option. Despite these advances, diabetes remains a major health challenge, and further research is needed to develop effective treatments and prevent its complications. This review covers various aspects of diabetes, including epidemiology, genetic and molecular basis, and recent advancements in therapeutics including herbal and synthetic peptides.

Notoginsenoside-R1 ameliorates palmitic acid-induced insulin resistance and oxidative stress in HUVEC via Nrf2/ARE pathway

Panax notoginseng, a Chinese traditional food and herb medicine, possesses notable cardiovascular health-promoting properties, with notoginsenoside (NG)-R1 being a key active compound. Insulin resistance represents a global health concern associated with various metabolic disorders. This study investigated the effects of NG-R1 on palmitic acid (PA)-induced insulin resistance and oxidative stress in human umbilical vein endothelial cells (HUVECs). Our findings demonstrate that NG-R1 significantly alleviated impaired glucose uptake, enhanced the phosphorylation of protein kinase B (PKB/Akt) at Ser473, and reduced the phosphorylation of insulin receptor substrate 1 (IRS-1) at Ser307 in PA-treated HUVECs. Furthermore, NG-R1 treatment significantly lowered the levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), while increasing the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). Additionally, NG-R1 activated the Nrf2/ARE signaling pathway, leading to a substantial increase in the expression of antioxidant enzymes. Notably, knockdown of Nrf2 attenuated the beneficial effects of NG-R1 on PA-induced insulin resistance and oxidative stress in HUVECs, suggesting that NG-R1 exerts its effects through the Nrf2/ARE pathway. In summary, our study reveals that NG-R1 ameliorated PA-induced insulin resistance in HUVECs via Nrf2/ARE pathway, providing novel insights into its potential for alleviating metabolic disorders and cardiovascular disease.

Research progress of NLRP3 inflammasome and its inhibitors with aging diseases

In recent years, a new target closely linked to a variety of diseases has appeared in the researchers' vision, which is the NLRP3 inflammasome. With the deepening of the study of NLRP3 inflammasome, it was found that it plays an extremely important role in a variety of physiological pathological processes, and NLRP3 inflammasome was also found to be associated with some age-related diseases. It is associated with the development of insulin resistance, Alzheimer's disease, Parkinson's, cardiovascular aging, hearing and vision loss. At present, the only clinical approach to the treatment of NLRP3 inflammasome-related diseases is to use anti-IL-1β antibodies, but NLRP3-specific inhibitors may be better than the IL-1β antibodies. This article reviews the relationship between NLRP3 inflammasome and aging diseases: summarizes some of the relevant experimental results reported in recent years, and introduces the biological signals or pathways closely related to the NLRP3 inflammasome in a variety of aging diseases, and also introduces some promising small molecule inhibitors of NLRP3 inflammasome for clinical treatment, such as: ZYIL1, DFV890 and OLT1177, they have excellent pharmacological effects and good pharmacokinetics.

Physiological Mechanisms Inherent to Diabetes Involved in the Development of Dementia: Alzheimer's Disease

Type 2 diabetes mellitus (T2D) is a metabolic disease reaching pandemic levels worldwide. In parallel, Alzheimer's disease (AD) and vascular dementia (VaD) are the two leading causes of dementia in an increasingly long-living Western society. Numerous epidemiological studies support the role of T2D as a risk factor for the development of dementia. However, few basic science studies have focused on the possible mechanisms involved in this relationship. On the other hand, this review of the literature also aims to explore the relationship between T2D, AD and VaD. The data found show that there are several alterations in the central nervous system that may be promoting the development of T2D. In addition, there are some mechanisms by which T2D may contribute to the development of neurodegenerative diseases such as AD or VaD.

The functions of SID1 transmembrane family, member 2 (Sidt2)

The SID1 transmembrane family, member 2, namely, Sidt2, is a highly glycosylated multichannel lysosomal transmembrane protein, but its specific physiological function remains unknown. Lysosomal membrane proteins are very important for the executive functioning of lysosomes. As an important part of the lysosomal membrane, Sidt2 can maintain the normal morphology of lysosomes and help stabilize them from the acidic pH environment within. As a receptor/transporter, it binds and transports nucleic acids and mediates the uptake and degradation of RNA and DNA by the lysosome. During glucose metabolism, deletion of Sidt2 can cause an increase in fasting blood glucose and the impairment of grape tolerance, which is closely related to the secretion of insulin. During lipid metabolism, the loss of Sidt2 can cause hepatic steatosis and lipid metabolism disorders and can also play a role in signal regulation and transport. Here, we review the function of the lysosomal membrane protein Sidt2, and focus on its role in glucose and lipid metabolism, autophagy and nucleotide (DNA/RNA) transport.

HM-chromanone alleviates hyperglycemia and inflammation in mice with endotoxin-induced insulin resistance

This study was designed to investigate whether (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone alleviates inflammation and hyperglycemia in mice with endotoxin-induced insulin resistance. (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone (10, 30, and 50 mg/kg bodyweight) was orally pre-administered to C57BL/6 J mice. An hour later, lipopolysaccharides (20 mg/kg bodyweight) was administered intraperitoneally to induce endotoxins. Blood samples were collected from the tail vein of the mice every 0, 30, and 90 min. The results indicated that (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone effectively regulated blood glucose levels in mice with endotoxin-induced insulin resistance. Furthermore, (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone significantly reduced the phosphorylation of mammalian target of rapamycin, ribosomal protein S6 kinase 1, and protein kinase C θ. Additionally, (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone suppressed the phosphorylation of c-Jun-NH2-terminal kinase and IkB kinase β, thereby decreasing the phosphorylation of inhibitor of nuclear factor kappa-B α and activating the nuclear factor-κB and activator protein-1 in the liver. Therefore, the expression of tumor necrosis factor-α, interleukin-6, and interleukin-1β was significantly reduced by suppressing the nuclear factor-κB and activator protein 1 activity. Suppression of mammalian target of rapamycin, S6 kinase 1, protein kinase C θ, c-Jun-NH2-terminal kinase, and IkB kinase β also ameliorated insulin resistance by reducing the phosphorylation of insulin receptor substrate-1 serine 307, thereby decreasing hyperglycemia. These findings suggest that (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone can alleviate hyperglycemia and inflammation in mice with endotoxin-induced insulin resistance.

Transcriptional Modulation Reveals Physiological Responses to Temperature Adaptation in Acrossocheilus fasciatus

In order to explore the molecular regulatory mechanism of temperature acclimation under long-term temperature stress in Acrossocheilus fasciatus, this study used high-throughput sequencing technology to analyze 60 days of breeding under five temperature conditions (12 °C, 16 °C, 20 °C, 24 °C, 28 °C). Compared with 20 °C, 9202, 4959 differentially expressed genes (DEGs) were discovered in low-temperature groups (12 °C, 16 °C), whereas 133 and 878 DEGs were discovered in high-temperature groups (24 °C, 28 °C), respectively. The KEGG functional enrichment analysis revealed that DEGs were primarily enriched in tight junction, PI3 K-Akt signaling pathway and protein digestion and absorption in low-temperature groups, and mainly enriched in proximal tubule bicarbonate reclamation, protein digestion and absorption, and HIF-1 signaling pathway in high-temperature groups. The viability of transcriptome sequencing-based screening of DEGs for temperature adaptation in A. fasciatus was shown by the selection of eight DEGs for further validation by quantitative real-time PCR (qRT-PCR), the findings of which were consistent with the RNA-seq data. According to the findings, protein digestion and absorption were primarily regulated by temperature variations, physiological stress was a significant regulator in regulation under high-temperature stress, and the immune system was a significant regulator in regulation under low-temperature stress. The transcriptional patterns of A. fasciatus under temperature stress are revealed in this study. This knowledge is crucial for understanding how A. fasciatus adapts to temperature and can help us better comprehend the environmental difficulties that A. fasciatus adaptation faces.

Assessing temporal differences in the predictive power of baseline TyG-related parameters for future diabetes: an analysis using time-dependent receiver operating characteristics

BACKGROUND

It is known that measuring the triglyceride glucose (TyG) index and TyG-related parameters [triglyceride glucose-body mass index (TyG-BMI), triglyceride glucose-waist circumference (TyG-WC), and triglyceride glucose-waist to height ratio (TyG-WHtR)] can predict diabetes; this study aimed to compare the predictive value of the baseline TyG index and TyG-related parameters for the onset of diabetes at different future periods.

METHODS

We conducted a longitudinal cohort study involving 15,464 Japanese people who had undergone health physical examinations. The subject's TyG index and TyG-related parameters were measured at the first physical examination, and diabetes was defined according to the American Diabetes Association criteria. Multivariate Cox regression models and time-dependent receiver operating characteristic (ROC) curves were constructed to examine and compare the risk assessment/predictive value of the TyG index and TyG-related parameters for the onset of diabetes in different future periods.

RESULTS

The mean follow-up period of the current study cohort was 6.13 years, with a maximum of 13 years, and the incidence density of diabetes was 39.88/10,000 person-years. In multivariate Cox regression models with standardized hazard ratios (HRs), we found that both the TyG index and TyG-related parameters were significantly and positively associated with diabetes risk and that the TyG-related parameters were stronger in assessing diabetes risk than the TyG index, with TyG-WC being the best parameter (HR per SD increase: 1.70, 95% CI 1.46, 1.97). In addition, TyG-WC also showed the highest predictive accuracy in time-dependent ROC analysis for diabetes occurring in the short-term (2-6 years), while TyG-WHtR had the highest predictive accuracy and the most stable predictive threshold for predicting the onset of diabetes in the medium- to long-term (6-12 years).

CONCLUSIONS

These results suggest that the TyG index combined with BMI, WC, and WHtR can further improve its ability to assess/predict the risk of diabetes in different future periods, where TyG-WC was not only the best parameter for assessing diabetes risk but also the best risk marker for predicting future diabetes in the short-term, while TyG-WHtR may be more suitable for predicting future diabetes in the medium- to long-term.

Mulberry extract ameliorates T2DM-related symptoms via AMPK pathway in STZ-HFD-induced C57BL/6J mice

ETHNOPHARMACOLOGICAL RELEVANCE

Mulberry (Morus alba L.) is not only a tasty food but also a beneficial medicinal substance that has been historically used to treat diabetes, as recorded in Tang Ben Cao. Recent research on animal models has shown that the ethyl acetate extract of Morus alba L. fruits (EMF) has hypoglycemic and hypolipidemic properties. However, there is a lack of documentation on the specific mechanisms through which EMF exerts its hypoglycemic effects.

OBJECTIVE OF THE STUDY

This study aimed to investigate the impact of EMF on L6 cells and C57/BL6J mice and to elucidate the potential mechanisms underlying its effects. The findings of this study can contribute to the existing evidence for the application of EMF as a therapeutic drug or dietary supplement in the management of type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

The UPLC-Q-TOF-MS technique was utilized to gather MS data. Masslynx 4.1 software in conjunction with the SciFinder database and other relevant references were used to analyze and identify the chemical composition of EMF. A series of in vitro investigations including MTT assay, glucose uptake assay and Western blot analysis were performed using an L6 cell model stably expressing IRAP-mOrange after EMF treatment. In vivo investigations were performed on a STZ-HFD co-induced T2DM mouse model, which included assessments of body composition, biochemical tests, histopathological analysis, and Western blot analysis.

RESULTS

MTT results revealed that EMF had no toxic effects on the cells at various concentrations. When EMF was administered to L6 cells, there was an increase in glucose transporter type 4 (GLUT4) translocation activity and a significant dose-dependent enhancement of glucose uptake by L6 myotubes. EMF treatment led to a marked increase in P-AMPK levels and GLUT4 expression in the cells, but these effects were reversed by an AMPK inhibitor (Compound C). In diabetic mice with STZ-HFD-induced diabetes, EMF treatment improved oral glucose tolerance, hyperglycemia, and hyperinsulinemia. Furthermore, EMF supplementation significantly reduced insulin resistance (IR) in diabetic mice, as evaluated using a steady-state model of the insulin resistance index. Histopathological sections demonstrated that acute EMF treatment reduced hepatic steatosis, pancreatic damage, and adipocyte hypertrophy. Western blot analysis demonstrated that EMF treatment also reduced abnormally high PPARγ expression, elevated the level of p-AMPK and p-ACC, and augmented the abundance of GLUT4 in insulin-sensitive peripheral tissues.

SUMMARY

The results suggest that EMF may exert beneficial effects on T2DM through the AMPK/GLUT4 and AMPK/ACC pathways, as well as by regulating PPARγ expression.

Stress and Diabetes Mellitus: Pathogenetic Mechanisms and Clinical Outcome

Evidence suggests that psychological and physical stress are relevant triggering factors for the onset of type 1 diabetes (T1D) and type 2 diabetes (T2D). The underlying mechanisms involve a complex neuroendocrine structure, involving the central nervous system and the periphery. Psychological stress leads to an increase of serum glucocorticoid concentrations and catecholamines release increasing the insulin need and the insulin resistance. According to the β-cell stress hypothesis, also causes of increased insulin demand, such as rapid growth, overweight, puberty, low physical activity, trauma, infections, and glucose overload, are potentially relevant factors in development of T1D. It has also been demonstrated that chronic stress and obesity form a vicious circle which leads to a definitive metabolic failure, increasing the risk of developing T2D. In this review, we will provide the most recent data concerning the role of stress in the outcomes of T1D and T2D, with a focus on the role of physical and psychological stress on the onset of T1D.

Molecular Genetics of Abnormal Redox Homeostasis in Type 2 Diabetes Mellitus

Numerous studies have shown that oxidative stress resulting from an imbalance between the production of free radicals and their neutralization by antioxidant enzymes is one of the major pathological disorders underlying the development and progression of type 2 diabetes (T2D). The present review summarizes the current state of the art advances in understanding the role of abnormal redox homeostasis in the molecular mechanisms of T2D and provides comprehensive information on the characteristics and biological functions of antioxidant and oxidative enzymes, as well as discusses genetic studies conducted so far in order to investigate the contribution of polymorphisms in genes encoding redox state-regulating enzymes to the disease pathogenesis.

Protein persulfidation: Rewiring the hydrogen sulfide signaling in cell stress response

The past few decades have witnessed significant progress in the discovery of hydrogen sulfide (H₂S) as a ubiquitous gaseous signaling molecule in mammalian physiology, akin to nitric oxide and carbon monoxide. As the third gasotransmitter, H₂S is now known to exert a wide range of physiological and cytoprotective functions in the biological systems. However, endogenous H₂S concentrations are usually low, and its potential biologic mechanisms responsible have not yet been fully clarified. Recently, a growing body of evidence has demonstrated that protein persulfidation, a posttranslational modification of cysteine residues (RSH) to persulfides (RSSH) elicited by H₂S, is a fundamental mechanism of H₂S-mediated signaling pathways. Persulfidation, as a biological switch for protein function, plays an important role in the maintenance of cell homeostasis in response to various internal and external stress stimuli and is also implicated in numerous diseases, such as cardiovascular and neurodegenerative diseases and cancer. In this review, the biological significance of protein persulfidation by H₂S in cell stress response is reviewed providing a framework for understanding the multifaceted roles of H₂S. A mechanism-guided perspective can help open novel avenues for the exploitation of therapeutics based on H₂S-induced persulfidation in the context of diseases.

Role of ceramides in diabetic foot ulcers (Review)

Diabetes mellitus (DM) is a metabolic disorder, which if not managed properly, can lead to serious health problems over time and impose significant financial burden on the patient, their family and society as a whole. The study of this disease and the underlying biological mechanism is gaining momentum. Multiple pieces of conclusive evidence show that ceramides are involved in the occurrence and development of diabetes. The present review focuses on the function of ceramides, a type of sphingolipid signaling molecule, to provide a brief description of ceramides and their metabolism, discuss the significant roles of ceramides in the healthy skin barrier, and speculate on the potential involvement of ceramides in the pathogenesis and development of diabetic foot ulcers (DFUs). Understanding these aspects of this disease more thoroughly is crucial to establish how ceramides contribute to the etiology of diabetic foot infections and identify possible therapeutic targets for the treatment of DFUs.

Structural Characterization and Hypoglycemic Function of Polysaccharides from Cordyceps cicadae

The polysaccharides isolated and purified from different parts of the medicinal fungus Cordyceps cicadae were identified, and three extracts displaying significant biological activities were selected for further study. The bacterium substance polysaccharides (BSP), spore powder polysaccharides (SPP), and pure powder polysaccharides (PPP) were separated, purified, and collected from the sclerotia, spores, and fruiting bodies of Cordyceps cicadae, respectively. The structures of Cordyceps cicadae polysaccharides were analyzed using gas chromatography, Fourier-transform infrared spectroscopy, methylation analysis, and one-dimensional (¹H and ¹³C) nuclear magnetic resonance spectroscopy. Moreover, the hypoglycemic effect of Cordyceps cicadae polysaccharides was examined in both in vitro and in vivo models. BSP, SPP, and PPP significantly increased glucose absorption in HepG2 cells, and alleviated insulin resistance (IR) in the in vitro model. SPP was the most effective, and was therefore selected for further study of its hypoglycemic effect in vivo. SPP effectively improved body weight and glucose and lipid metabolism in type 2 diabetes model mice, in addition to exerting a protective effect on liver injury. SPP regulated the mRNA expression of key PI3K/Akt genes involved in the insulin signaling pathway. The hypoglycemic mechanism of SPP may reduce hepatic insulin resistance by activating the PI3K/Akt signaling pathway. Spore powder polysaccharides (SPP) extracted from Cordyceps cicadae effectively improved body weight and glucose and lipid metabolism in type 2 diabetes model mice, in addition to exerting a protective effect on liver injury. The mechanism underlying the hypoglycemic effect of SPP regulates the mRNA expression of key PI3K/Akt genes involved in the insulin signaling pathway to alleviate insulin resistance. Our results provide a theoretical basis for research into the hypoglycemic effect of Cordyceps cicadae, and lay the foundation for the development of functional products.

Nutri-stress, mitochondrial dysfunction, and insulin resistance-role of heat shock proteins

Excess nutrient flux into the cellular energy system results in a scenario of cellular metabolic stress in diseases involving insulin resistance, such as type 2 diabetes, referred to as nutri-stress and results in cellular bioenergetic imbalance, which leads to insulin resistance and disease. Under nutri-stress, the heat shock response system is compromised due to metabolic abnormalities that disturb energy homeostasis. Heat shock proteins (HSPs) are the chief protectors of intracellular homeostasis during stress. Heat shock response (HSR) impairment contributes to several metabolic pathways that aggravate chronic hyperglycaemia and insulin resistance, highlighting a central role in disease pathogenesis. This article discusses the role of nutri-stress-related molecular events in causing insulin resistance and the nature of the roles played by heat shock proteins in some of the crucial checkpoints of the molecular networks involved in insulin resistance. Ample evidence suggests that the heat shock machinery regulates critical pathways in mitochondrial function and energy metabolism and that cellular energy status highly influences it. Weakening of HSPs, therefore, leads to loss of their vital cytoprotective functions, propagating nutri-stress in the system. Further research into the mechanistic roles of HSPs in metabolic homeostasis will help widen our understanding of lifestyle diseases, their onset, and complications. These inducible proteins may be crucial to attenuating lifestyle risk factors and disease management.

Energy Crisis Links to Autophagy and Ferroptosis in Alzheimer's Disease: Current Evidence and Future Avenues

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases worldwide. The occult nature of the onset and the uncertainty of the etiology largely impede the development of therapeutic strategies for AD. Previous studies revealed that the disorder of energy metabolism in the brains of AD patients appears far earlier than the typical pathological features of AD, suggesting a tight association between energy crisis and the onset of AD. Energy crisis in the brain is known to be induced by the reductions in glucose uptake and utilization, which may be ascribed to the diminished expressions of cerebral glucose transporters (GLUTs), insulin resistance, mitochondrial dysfunctions, and lactate dysmetabolism. Notably, the energy sensors such as peroxisome proliferators-activated receptor (PPAR), transcription factor EB (TFEB), and AMP-activated protein kinase (AMPK) were shown to be the critical regulators of autophagy, which play important roles in regulating beta-amyloid (Aβ) metabolism, tau phosphorylation, neuroinflammation, iron dynamics, as well as ferroptosis. In this study, we summarized the current knowledge on the molecular mechanisms involved in the energy dysmetabolism of AD and discussed the interplays existing between energy crisis, autophagy, and ferroptosis. In addition, we highlighted the potential network in which autophagy may serve as a bridge between energy crisis and ferroptosis in the progression of AD. A deeper understanding of the relationship between energy dysmetabolism and AD may provide new insight into developing strategies for treating AD; meanwhile, the energy crisis in the progression of AD should gain more attention.

The Common Single Cause of Chronic Multi-Hormonal Resistance in Oxidative Stress

In diseases with concomitant oxidative stress, chronic multi-hormonal resistances could be detected. The most conspicuous component of these resistances is insulin resistance, but also leptin, erythropoietin, acetylcholine, triiodothyronine and glucagon-like peptide-1 resistances also occur. On the other hand, in oxidative stress, abnormal tyrosines, for instance, meta- and ortho-tyrosine are also produced and incorporated into the proteins through the translational process. In case these modified proteins are components of the intracellular signalling pathways, a hormonal resistance may develop. The above-mentioned hormones, owning overlapping signalling pathways at the insulin receptor substrate, develop an abnormal tyrosine phosphorylation dependent chronic multi-hormonal resistance. A few weeks free of oxidative stress or the use of antioxidant therapy are required to provide a return from this resistance, which return may be further supported by the supplementation of physiological para-tyrosine and by the add-on therapy of a pharmacological dose of glucagon-like peptide-1 receptor agonist, which is able to bypass the critical insulin receptor substrate signalling.

Association between blood selenium levels and gestational diabetes mellitus: A systematic review and meta-analysis

Introduction

The association between blood (serum or plasma) selenium concentrations and gestational diabetes mellitus (GDM) has been evaluated in some studies. However, the reported findings are debatable, and only case-control and cross-sectional studies were included.

Objective

This research aimed to assess the association between blood selenium levels and GDM by analyzing existing literature. To provide a reference for the prevention and treatment of GDM, we included prospective studies which are not included in previous studies to collate more high-quality evidence and better test the etiological hypothesis between blood Se concentrations and GDM.

Methods

The PubMed, EMBASE, and Web of Science databases were retrieved for literature up to September 2022, and relevant references were manually searched. Raw data from relevant studies were extracted, and a random effect model was adopted for meta-analysis. The total effects were reported as weighted mean differences. All data were analyzed using Stata 16.0 software.

Results

Fourteen studies involving 890 pregnant women with GDM and 1618 healthy pregnant women were incorporated in the meta-analysis. Pregnancies with GDM had significantly lower blood selenium levels than those with normal glucose tolerance (weighted mean difference = -8.11; 95% confidence interval: -12.68 to -3.54, P = 0.001). Subgroup analyses showed that the association between blood selenium levels and GDM was consistent in the residents of Asia and Africa, but not in European. This trend was significant in the second and third trimester subgroups, but not in the first trimester subgroup. Articles published in 2006-2015 also showed this trend, but those published before 2005 and 2016-2019 did not show significant results. This difference was evident in non-prospective studies, but not significant in prospective studies. Studies using the Carpenter and Coustan diagnostic criteria were consistent with this trend, whereas studies using other diagnostic criteria found no differences. In addition, in terms of blood selenium measurement methods, atomic absorption spectrometry showed more significant differences than other methods. In the subgroup analysis based on the sample size of included studies and the quality of the studies, each subgroup showed statistical differences.

Conclusion

Lower blood selenium concentrations are associated with GDM as shown in our study. Therefore, supplementing an appropriate amount of selenium may be helpful for GDM prevention and treatment.

Low-Carbohydrate High-Fat Diet: A SWOC Analysis

Insulin resistance (IR) plays a role in the pathogenesis of many diseases, such as type 2 diabetes mellitus, cardiovascular disease, non-alcoholic fatty liver disease, obesity, and neurodegenerative diseases, including Alzheimer's disease. The ketogenic diet (KD) is a low-carbohydrate/high-fat diet that arose in the 1920s as an effective treatment for seizure control. Since then, the KD has been studied as a therapeutic approach for various IR-related disorders with successful results. To date, the use of the KD is still debatable regarding its safety. Some studies have acknowledged its usefulness, while others do not recommend its long-term implementation. In this review, we applied a SWOC (Strengths, Weaknesses, Opportunities, and Challenges) analysis that revealed the positive, constructive strengths of the KD, its potential complications, different conditions that can make used for it, and the challenges faced by both physicians and subjects throughout a KD. This SWOC analysis showed that the KD works on the pathophysiological mechanism of IR-related disorders such as chronic inflammation, oxidative stress and mitochondrial stress. Furthermore, the implementation of the KD as a potential adjuvant therapy for many diseases, including cancer, neurodegenerative disorders, polycystic ovary syndrome, and pain management was proven. On the other hand, the short and long-term possible undesirable KD-related effects, including nutritional deficiencies, growth retardation and nephrolithiasis, should be considered and strictly monitored. Conclusively, this review provides a context for decision-makers, physicians, researchers, and the general population to focus on this dietary intervention in preventing and treating diseases. Moreover, it draws the attention of scientists and physicians towards the opportunities and challenges associated with the KD that requires attention before KD initiation.

Stress-Induced Diabetes: A Review

It has long been established that stress has a significant impact on metabolic function. Type 2 diabetes may be initiated by psychological and physical stress. The central and peripheral nervous systems are both involved in the neuroendocrine framework that underlies the underlying processes. The release of catecholamines and a rise in serum glucocorticoid concentrations caused by psychological stress enhance the requirement for insulin and insulin resistance. Experiencing persistent hyperglycemia in people with diabetes may be influenced by stress. Blood sugar levels may rise due to hormones being released in response to stress. Although this has adaptive significance in a healthy patient, in the long run, it can cause insulin resistance and lead to diabetes. Additionally, diabetes may cause abnormalities in the regulation of these stress hormones.

Associations of Serum Total 25OHD, 25OHD3, and epi-25OHD3 with Insulin Resistance: Cross-Sectional Analysis of the National Health and Nutrition Examination Survey, 2011–2016

Background: Vitamin D may have a role in insulin sensitivity. However, the data on the association between various metabolites of Vitamin D and insulin-related parameters have been limited. Methods: We identified 6026 adults aged 20–80 years who participated in the 2011–2016 National Health and Nutrition Examination Survey (NHANES). Serum total 25OHD, 25OHD3, and epi-25OHD3, fasting glucose, insulin, and HOMA2-IR were obtained from the NHANES data. The association between serum Vitamin D-related values and insulin resistance was analyzed using a generalized linear model. For risk analysis, multifactorial logistic regression was used. Results: The median total 25-hydroxyvitamin D level, 25-hydroxyvitamin D3 level, and 3-epi-25-hydroxyvitamin D3 level were 62.5 nmol/L, 58.8 nmol/L, and 3.3 nmol/L, respectively. After adjustment for sex, age, race, ethnicity, and education status, the ORs for the insulin resistance of participants of total 25-hydroxyvitamin D, 25-hydroxyvitamin D3, and 3-epi-25-hydroxyvitamin D3 were 0.32 (95% CI 0.24, 0.43), 0.34 (95% CI 0.26, 0.44), and 0.64 (95% CI 0.53, 0.77), respectively. After an adjustment for body mass index, diabetes, and drinking and smoking, the ORs for the insulin resistance of the participants for total 25-hydroxyvitamin D, 25-hydroxyvitamin D3, and 3-epi-25-hydroxyvitamin D3 were 0.56 (95% CI 0.40, 0.78), 0.63 (95% CI 0.46, 0.85), and 0.99 (95% CI 0.80, 1.24), respectively. Conclusions: Our study provides suggestive evidence for the association between Vitamin D concentrations and a lower risk of insulin resistance. Evidence from larger and more adequately powered cohort studies is needed to confirm our results.

Effects of antioxidant intervention in patients with polycystic ovarian syndrome: A systematic review and meta-analysis

BACKGROUND

The role of antioxidant intervention in polycystic ovary syndrome (PCOS) patients has been increasingly investigated in recent years. In order to further clarify whether antioxidant therapy is beneficial for PCOS patients and the emphasis of its effects, this study provides a systematic review and meta-analysis of randomized controlled trials examining the effect of antioxidant intervention on PCOS.

METHODS

Enrolled study designs related to antioxidant interventions and PCOS, published from 1999 to 2020, were searched from EMBASE, PubMed, and Web of Science databases to sort out proven studies on antioxidant interventions and PCOS. Data were reported as weighted mean difference (WMD) or standard mean difference with associated confidence intervals of 95%. The analysis was conducted using Stata version 16.0.

RESULTS

Twenty-three studies were included in total. Antioxidant intervention had a positive impact on homeostasis model assessment of insulin resistance (WMD = -0.37, P = .011) and Triglycerides (WMD = -25.51, P < .001). And antioxidant intervention did not improve testosterone levels significantly (WMD = -0.20, P = .2611). Subgroup analysis showed that except for the D-chiro-inosito subgroup, no difference in body mass index was observed between the intervention group and the control group.

CONCLUSIONS

This meta-analysis demonstrates the efficacy of antioxidant intervention in patients with PCOS, demonstrating that antioxidant intervention has a significant effect on insulin resistance and lipid metabolism improvement. However, antioxidant intervention therapy has no discernible impact on testosterone levels or body mass index. Omega-3 may be a more effective antioxidant intervention for PCOS. In addition, this meta-analysis provides important reference opinions and treatment recommendations for PCOS.

Redox signaling at the crossroads of human health and disease

Redox biology is at the core of life sciences, accompanied by the close correlation of redox processes with biological activities. Redox homeostasis is a prerequisite for human health, in which the physiological levels of nonradical reactive oxygen species (ROS) function as the primary second messengers to modulate physiological redox signaling by orchestrating multiple redox sensors. However, excessive ROS accumulation, termed oxidative stress (OS), leads to biomolecule damage and subsequent occurrence of various diseases such as type 2 diabetes, atherosclerosis, and cancer. Herein, starting with the evolution of redox biology, we reveal the roles of ROS as multifaceted physiological modulators to mediate redox signaling and sustain redox homeostasis. In addition, we also emphasize the detailed OS mechanisms involved in the initiation and development of several important diseases. ROS as a double-edged sword in disease progression suggest two different therapeutic strategies to treat redox-relevant diseases, in which targeting ROS sources and redox-related effectors to manipulate redox homeostasis will largely promote precision medicine. Therefore, a comprehensive understanding of the redox signaling networks under physiological and pathological conditions will facilitate the development of redox medicine and benefit patients with redox-relevant diseases.

Social isolation triggers oxidative status and impairs systemic and hepatic insulin sensitivity in normoglycemic rats

Drug-naïve psychotic patients show metabolic and hepatic dysfunctions. The rat social isolation model of psychosis allows to investigate mechanisms leading to these disturbances to which oxidative stress crucially contributes. Here, we investigated isolation-induced central and peripheral dysfunctions in glucose homeostasis and insulin sensitivity, along with redox dysregulation. Social isolation did not affect basal glycemic levels and the response to glucose and insulin loads in the glucose and insulin tolerance tests. However, HOMA-Index value were increased in isolated (ISO) rats. A hypothalamic reduction of AKT phosphorylation and a trend toward an increase in AMPK phosphorylation were observed following social isolation, accompanied by reduced GLUT-4 levels. Social isolation also induced a reduction of phosphorylation of the insulin receptor, of AKT and GLUT-2, and a decreased phosphorylation of AMPK in the liver. Furthermore, a significant reduction in hepatic CPT1 and PPAR-α levels was detected. ISO rats also showed significant elevations in hepatic ROS amount, lipid peroxidation and NOX4 expression, whereas no differences were detected in NOX2 and NOX1 levels. Expression of SOD2 in the mitochondrial fraction and SOD1 in the cytosolic fraction was not altered following social isolation, whereas SOD activity was increased. Furthermore, a decrease of hepatic CAT and GSH amount was observed in ISO rats compared to GRP animals. Our data suggest that the increased oxidant status and antioxidant capacity modifications may trigger hepatic and systemic insulin resistance, by altering signal hormone pathway and sustaining subsequent alteration of glucose homeostasis and metabolic impairment observed in the social isolation model of psychosis.

Role of Oxidative Stress in Diabetic Cardiomyopathy

Type 2 diabetes is a redox disease. Oxidative stress and chronic inflammation induce a switch of metabolic homeostatic set points, leading to glucose intolerance. Several diabetes-specific mechanisms contribute to prominent oxidative distress in the heart, resulting in the development of diabetic cardiomyopathy. Mitochondrial overproduction of reactive oxygen species in diabetic subjects is not only caused by intracellular hyperglycemia in the microvasculature but is also the result of increased fatty oxidation and lipotoxicity in cardiomyocytes. Mitochondrial overproduction of superoxide anion radicals induces, via inhibition of glyceraldehyde 3-phosphate dehydrogenase, an increased polyol pathway flux, increased formation of advanced glycation end-products (AGE) and activation of the receptor for AGE (RAGE), activation of protein kinase C isoforms, and an increased hexosamine pathway flux. These pathways not only directly contribute to diabetic cardiomyopathy but are themselves a source of additional reactive oxygen species. Reactive oxygen species and oxidative distress lead to cell dysfunction and cellular injury not only via protein oxidation, lipid peroxidation, DNA damage, and oxidative changes in microRNAs but also via activation of stress-sensitive pathways and redox regulation. Investigations in animal models of diabetic cardiomyopathy have consistently demonstrated that increased expression of the primary antioxidant enzymes attenuates myocardial pathology and improves cardiac function.

Clinical investigation of lipopolysaccharide in the persistence of metabolic syndrome (MS) through the activation of GRP78-IRE1α-ASK1 signaling pathway

OBJECTIVE

Endoplasmic reticulum stress (ERS) might play a pivotal role in the persistence of metabolic syndrome (MS). Lipopolysaccharide (LPS) derived from various gram-negative bacteria could result in the ERS. Therefore, we aimed to investigate the association between LPS and ERS in MS.

METHOD

We enrolled 86 patients with MS and 42 healthy people aged 35-65 years. Body weight, waist circumference, blood pressure were measured. LPS, LBP and inflammation factors, fasting plasma glucose (FPG), insulin, total cholesterol (TC), triglyceride, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), free fatty acid (FFA) were analyzed in blood plasma of patient's cohort. Body mass index (BMI) and HOMA-IR were calculated. The mRNA and protein expression of ERS GRP78, IRE1α, ASK1 and IKKβ, JNK1 were measured in blood plasma of patient's cohort by RT-PCR and Elisa. MS was defined by the updated National Cholesterol Education Program Adult Treatment Panel III criterion for Asian Americans.

RESULTS

BMI, waist circumference, blood pressure, FPG, insulin, HOMA-IR, TC, triglyceride, HDL-C, LDL-C, FFA and LPS, LBP, TNF-α, CRP, IL-1, IL-6, MCP-1 were significantly higher in patients with MS than healthy people (P < 0.001). The correlation analysis suggested that LPS were associated with TNF-α, IL-1, IL-6, MCP-1, LBP, FFA, HOMA-IR potently (P < 0.05). The marker gene and protein expressions of ERS (GRP78, IRE1α, ASK1, IKKβ and JNK) were significantly overexpressed in patients with MS and were positive correlation with LPS (P < 0.05).

CONCLUSION

LPS may play an important role in mediating chronic low-grade inflammation by activating the ERS GRP78-IRE1α-ASK1 signaling pathway, contributing to the persistence of MS.

Research progress of coumarins and their derivatives in the treatment of diabetes

Diabetes is a group of metabolic diseases characterised by chronic hyperglycaemia caused by multiple causes, which is caused by insulin secretion and/or utilisation defects. It is characterised by increased fasting and postprandial blood glucose levels due to insulin deficiency or insulin resistance. It is reported that the harm of diabetes mainly comes from its complications, and the cardiovascular disease caused by diabetes is the primary cause of its harm. China has the largest number of diabetic patients in the world, and the prevention and control of diabetes are facing great challenges. In recent years, many kinds of literature have been published abroad, which have proved that coumarin and its derivatives are effective in the treatment of diabetic complications such as nephropathy and cardiovascular disease. In this paper, the types of antidiabetic drugs and the anti-diabetic mechanism of coumarins were reviewed.