The origins and drivers of insulin resistance

Eriodictyol regulates white adipose tissue browning and hepatic lipid metabolism in high fat diet-induced obesity mice via activating AMPK/SIRT1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Blossom of Citrus aurantium L. var. amara Engl. (CAVA) has been popularly consumed as folk medicine and dietary supplement owing to its various beneficial effects and especially anti-obesity potential. Our previous study predicted that eriodictyol was probably one of the key active compounds of the total flavonoids from blossom of CAVA. However, effects of eriodictyol in anti-obesity were still elusive.

AIM OF THE STUDY

This study was performed to explore the precise role of eriodictyol in white adipose tissue (WAT) browning and hepatic lipid metabolism, and simultaneously, to verify the impact of eriodictyol on the total flavonoids of CAVA in losing weight.

MATERIALS AND METHODS

The pancreas lipase assay was conducted and oleic acid-induced HepG2 cells were established to preliminarily detect the lipid-lowering potential of eriodictyol. Then, high fat diet-induced obesity (DIO) mouse model was established for in vivo studies. The biochemical indicators of mice were tested by commercial kits. The histopathological changes of WAT and liver in mice were tested by H&E staining, Oil Red O staining and Sirius Red staining. Immunohistochemical, Western blot assay, as well as RT-qPCR analysis were further performed. Additionally, molecular docking assay was used to simulate the binding of eriodictyol with potential target proteins.

RESULTS

In vitro studies showed that eriodictyol intervention potently inhibited pancreatic lipase activity and reversed hepatic steatosis in oleic acid-induced HepG2 cells. Consistently, long-term medication of eriodictyol also effectively prevented obesity and improved lipid and glucose metabolism in diet-induced obesity mice. Obesity-induced histopathological changes in iWAT, eWAT and BAT, and abnormal expression levels of IL-10, IL-6 and TNF-α in iWAT of DIO mice were also significantly reversed by eriodictyol treatment. Eriodictyol administration significantly and potently promoted browning of iWAT by increasing expression levels of thermogenic marker protein of UCP1, as well as brown adipocyte-specific genes of PGC-1α, SIRT1 and AMPKα1. Further assays revealed that eriodictyol enhanced mitochondrial function, as shown by an increase in compound IV activity and the expression of tricarboxylic acid cycle-related genes. Besides, eriodictyol addition markedly reversed hepatic damages and hepatic inflammation, and enhanced hepatic lipid metabolism in DIO mice, as evidenced by its regulation on p-ACC, CPT1-α, UCP1, PPARα, PGC-1α, SIRT1 and p-AMPKα expression. Molecular docking results further validated that AMPK/SIRT1 pathway was probably the underlying mechanisms by which eriodictyol acted.

CONCLUSION

Eriodictyol exhibited significant anti-obesity effect, which was comparable to that of the total flavonoids from blossom of CAVA. These findings furnished theoretical basis for the application of eriodictyol in weight loss.

PPARγ-dependent remodeling of translational machinery in adipose progenitors is impaired in obesity

Adipose tissue regulates energy homeostasis and metabolic function, but its adaptability is impaired in obesity. In this study, we investigate the impact of acute PPARγ agonist treatment in obese mice and find significant transcriptional remodeling of cells in the stromal vascular fraction (SVF). Using single-cell RNA sequencing, we profile the SVF of inguinal and epididymal adipose tissue of obese mice following rosiglitazone treatment and find an induction of ribosomal factors in both progenitor and preadipocyte populations, while expression of ribosomal factors is reduced with obesity. Notably, the expression of a subset of ribosomal factors is directly regulated by PPARγ. Polysome profiling of the epididymal SVF shows that rosiglitazone promotes translational selectivity of mRNAs that encode pathways involved in adipogenesis and lipid metabolism. Inhibition of translation using a eukaryotic translation initiation factor 4A (eIF4A) inhibitor is sufficient in blocking adipogenesis. Our findings shed light on how PPARγ agonists promote adipose tissue plasticity in obesity.

Multi-layered proteomics identifies insulin-induced upregulation of the EphA2 receptor via the ERK pathway which is dependent on low IGF1R level

Insulin resistance impairs the cellular insulin response, and often precedes metabolic disorders, like type 2 diabetes, impacting an increasing number of people globally. Understanding the molecular mechanisms in hepatic insulin resistance is essential for early preventive treatments. To elucidate changes in insulin signal transduction associated with hepatocellular resistance, we employed a multi-layered mass spectrometry-based proteomics approach focused on insulin receptor (IR) signaling at the interactome, phosphoproteome, and proteome levels in a long-term hyperinsulinemia-induced insulin-resistant HepG2 cell line with a knockout of the insulin-like growth factor 1 receptor (IGF1R KO). The analysis revealed insulin-stimulated recruitment of the PI3K complex in both insulin-sensitive and -resistant cells. Phosphoproteomics showed attenuated signaling via the metabolic PI3K-AKT pathway but sustained extracellular signal-regulated kinase (ERK) activity in insulin-resistant cells. At the proteome level, the ephrin type-A receptor 2 (EphA2) showed an insulin-induced increase in expression, which occurred through the ERK signaling pathway and was concordantly independent of insulin resistance. Induction of EphA2 by insulin was confirmed in additional cell lines and observed uniquely in cells with high IR-to-IGF1R ratio. The multi-layered proteomics dataset provided insights into insulin signaling, serving as a resource to generate and test hypotheses, leading to an improved understanding of insulin resistance.

Assessing the validity of METS-IR for predicting the future onset of diabetes: an analysis using time-dependent receiver operating characteristics

BACKGROUND

The Metabolic Insulin Resistance Score (METS-IR) is a non-invasive proxy for insulin resistance (IR) that has been newly developed in recent years and has been shown to be associated with diabetes risk. Our aim was to assess the predictive value of METS-IR for the future development of diabetes and its temporal differences in people of different sex, age, and body mass index (BMI).

METHODS

The current study included 15,453 baseline non-diabetic subjects in the NAGALA cohort and then grouped according to the World Health Organization's (WHO) recommended criteria for age and BMI. Multivariate Cox regression and time-dependent receiver operator characteristics (ROC) curves were used to analyze the value of METS-IR in assessing and predicting the risk of diabetes in people of different sexes, ages, and BMIs.

RESULTS

373 individuals developed diabetes during the observation period. By multivariate COX regression analysis, the development of future diabetes was significantly associated with increased METS-IR, and this positive association was stronger in women than in men and in individuals < 45 years than in individuals ≥ 45 years; while no significant differences were observed between non-obese and overweight/obesity individuals. Using time-dependent ROC analysis we also assessed the predictive value of METS-IR for future diabetes at a total of 11-time points between 2 and 12 years. The results showed that METS-IR had a higher predictive value for the future development of diabetes in women or individuals < 45 years of age compared to men or individuals ≥ 45 years of age for almost the entire follow-up period. Furthermore, across different BMI categories, we also found that in the short term (3-5 years), METS-IR had a higher predictive value for the development of diabetes in individuals with overweight/obesity, while in the medium to long term (6-12 years), METS-IR was more accurate in predicting the development of diabetes in non-obese individuals.

CONCLUSIONS

Our study showed that METS-IR was independently associated with the development of future diabetes in a non-diabetic population. METS-IR was a good predictor of diabetes, especially for women and individuals < 45 years old for predicting the future risk of developing diabetes at all times.

Multiomics of the intestine-liver-adipose axis in multiple studies unveils a consistent link of the gut microbiota and the antiviral response with systemic glucose metabolism

BACKGROUND

The microbiota is emerging as a key factor in the predisposition to insulin resistance and obesity.

OBJECTIVE

To understand the interplay among gut microbiota and insulin sensitivity in multiple tissues.

DESIGN

Integrative multiomics and multitissue approach across six studies, combining euglycaemic clamp measurements (used in four of the six studies) with other measurements of glucose metabolism and insulin resistance (glycated haemoglobin (HbA1c) and fasting glucose).

RESULTS

Several genera and species from the Proteobacteria phylum were consistently negatively associated with insulin sensitivity in four studies (ADIPOINST, n=15; IRONMET, n=121, FLORINASH, n=67 and FLOROMIDIA, n=24). Transcriptomic analysis of the jejunum, ileum and colon revealed T cell-related signatures positively linked to insulin sensitivity. Proteobacteria in the ileum and colon were positively associated with HbA1c but negatively with the number of T cells. Jejunal deoxycholic acid was negatively associated with insulin sensitivity. Transcriptomics of subcutaneous adipose tissue (ADIPOMIT, n=740) and visceral adipose tissue (VAT) (ADIPOINST, n=29) revealed T cell-related signatures linked to HbA1c and insulin sensitivity, respectively. VAT Proteobacteria were negatively associated with insulin sensitivity. Multiomics and multitissue integration in the ADIPOINST and FLORINASH studies linked faecal Proteobacteria with jejunal and liver deoxycholic acid, as well as jejunal, VAT and liver transcriptomic signatures involved in the actin cytoskeleton, insulin and T cell signalling. Fasting glucose was consistently linked to interferon-induced genes and antiviral responses in the intestine and VAT. Studies in Drosophila melanogaster validated these human insulin sensitivity-associated changes.

CONCLUSION

These data provide comprehensive insights into the microbiome-gut-adipose-liver axis and its impact on systemic insulin action, suggesting potential therapeutic targets.Cite Now.

Macrophage and chondrocyte phenotypes in inflammation

Inflammation is a complex biological process protecting the body from diverse external threats. Effectively performing this task requires an intricate, well-regulated interplay of different cells and tissues. Furthermore, several cells participating in inflammation can assume diverse phenotypes. A classic and relatively well-studied example of phenotypic diversity in inflammation is macrophage polarization. Based on the TH1/TH2 phenotypes of T helper cells, this scheme has proinflammatory "classical/M1" activation contrasted with the anti-inflammatory and healing-promoting "alternative/M2" phenotype. Some authors have extended the concept into an M17 phenotype induced by the classic TH17 cytokine IL-17. Phenotypic changes in chondrocytes have also been studied especially in the context of osteoarthritis (OA), and there are indications that these cells can also assume polarized phenotypes at least partly analogous to those of TH cells and macrophages. The therapeutic success of biological agents targeting TH1/TH2/TH17 inductor and/or effector cytokines displays the utility of the concept of polarization. The aim of this focused review is to survey the internal and external factors affecting macrophage and chondrocyte phenotypes (such as inflammatory cytokines, widely used medications and natural products) and to explore the possibility of ameliorating pathological states by modulating these phenotypes.

Aerobic Exercise Prevents High-Fat-Diet-Induced Adipose Tissue Dysfunction in Male Mice

BACKGROUND/OBJECTIVES

This study aimed to assess the effect of aerobic exercise on capillary density and vascular smooth muscle cell (VSMC) phenotype in the visceral and subcutaneous adipose tissue of high-fat-diet (HFD) mice in order to understand the mechanisms underlying improvements in insulin resistance (IR) and chronic inflammation in adipose tissue (AT).

METHODS

Male C57BL/6J mice were divided into HFD and normal diet groups for 12 weeks and then further split into sedentary and aerobic exercise subgroups for an additional 8 weeks. Various parameters including body weight, fat weight, blood glucose, lipid profile, insulin levels, glucose tolerance, and inflammatory cytokines were evaluated.

RESULTS

Aerobic exercise reduced HFD-induced weight gain, IR, and improved lipid profiles. HFD had a minimal effect on inflammatory cytokines except in visceral adipose tissue (VAT). IR was associated with capillary density in subcutaneous adipose tissue (SAT) and VSMC phenotype in VAT. Aerobic exercise promoted anti-inflammatory responses in VAT, correlating with VSMC phenotype in this tissue.

CONCLUSIONS

Aerobic exercise can alleviate HFD-induced IR and inflammation through the modulation of VSMC phenotype in AT.

Association Between Mycobacterium tuberculosis Sensitization and Insulin Resistance Among US Adults Screened for Type 2 Diabetes Mellitus

Background

Type 2 diabetes mellitus (T2DM) may be a long-term sequela of infection with Mycobacterium tuberculosis (Mtb) by mechanisms that remain to be fully explained. We evaluated the association between Mtb sensitization and T2DM and, via mediation analysis, the extent to which it is mediated by insulin resistance and/or β-cell failure.

Methods

Adults were assessed for T2DM by fasting plasma glucose, 2-hour oral glucose tolerance testing, and hemoglobin A1c; β-cell dysfunction and insulin resistance by homoeostasis model assessment 2; and Mtb sensitization by tuberculin skin testing. Associations between Mtb sensitization and T2DM were modeled with probit regression and decomposed into indirect effects of β-cell dysfunction and insulin resistance. Analyses were adjusted for sociodemographic, behavioral, and clinical characteristics.

Results

We included 1843 adults. Individuals with Mtb sensitization were older than those without Mtb (median [IQR], 54 [39-64] vs 47 [33-62] years). As compared with being uninfected, Mtb sensitization was associated with T2DM (adjusted absolute risk difference, 9.34% [95% CI, 2.38%-15.0%]; P < .001) and increased insulin resistance (adjusted median difference, 0.16 [95% CI, .03-.29]; P = .014) but not β-cell dysfunction (adjusted median difference, -3.1 [95% CI, -10.4 to 4.3]; P = .42). In mediation analyses, insulin resistance mediated 18.3% (95% CI, 3.29%-36.0%; P = .020) of the total effect of the association between Mtb sensitization and T2DM.

Conclusions

Definitive prospective studies examining incident T2DM following tuberculosis are warranted. Notwithstanding, our findings suggest that exposure to Mtb may be a novel risk factor for T2DM, likely driven by an increase in insulin resistance.

Obesity alters adipose tissue response to fasting and refeeding in women: A study on lipolytic and endocrine dynamics and acute insulin resistance

Fasting induces significant shifts in substrate utilization with signs of acute insulin resistance (IR), while obesity is associated with chronic IR. Nonetheless, both states substantially influence adipose tissue (AT) function. Therefore, in this interventional study (NCT04260542), we investigated if excessive adiposity in premenopausal women alters insulin sensitivity and AT metabolic and endocrine activity in response to a 60-h fast and a subsequent 48-h refeeding period. Using physiological methods, lipidomics, and AT explants, we showed that obesity partially modified AT endocrine activity and blunted the dynamics of AT insulin resistance in response to the fasting/refeeding challenge compared to that observed in lean women. AT adapted to its own excess by reducing lipolytic activity/free fatty acids (FFA) flux per mass. This adaptation persisted even after a 60-h fast, resulting in lower ketosis in women with obesity. This could be a protective mechanism that limits the lipotoxic effects of FFA; however, it may ultimately impede desirable weight loss induced by caloric restriction in women with obesity.

Mesenchymal Stem Cell-Derived Exosomes Attenuate Hepatic Steatosis and Insulin Resistance in Diet-Induced Obese Mice by Activating the FGF21-Adiponectin Axis

Exosomes derived from mesenchymal stem cells have shown promise in treating metabolic disorders, yet their specific mechanisms remain largely unclear. This study investigates the protective effects of exosomes from human umbilical cord Wharton's jelly mesenchymal stem cells (hWJMSCs) against adiposity and insulin resistance in high-fat diet (HFD)-induced obese mice. HFD-fed mice treated with hWJMSC-derived exosomes demonstrated improved gut barrier integrity, which restored immune balance in the liver and adipose tissues by reducing macrophage infiltration and pro-inflammatory cytokine expression. Furthermore, these exosomes normalized lipid metabolism including lipid oxidation and lipogenesis, which alleviate lipotoxicity-induced endoplasmic reticulum (ER) stress, thereby decreasing fat accumulation and chronic tissue inflammation in hepatic and adipose tissues. Notably, hWJMSC-derived exosomes also promoted browning and thermogenic capacity of adipose tissues, which was linked to reduced fibroblast growth factor 21 (FGF21) resistance and increased adiponectin production. This process activated the AMPK-SIRT1-PGC-1α pathway, highlighting the role of the FGF21-adiponectin axis. Our findings elucidate the molecular mechanisms through which hWJMSC-derived exosomes counteract HFD-induced metabolic dysfunctions, supporting their potential as therapeutic agents for metabolic disorders.

Unraveling the mechanisms of hepatogenous diabetes and its therapeutic perspectives

The review focused mainly on the pathogenesis of hepatogenous diabetes (HD) in liver cirrhosis (LC). This review reveals parallels between the mechanisms of metabolic dysfunction observed in LC and type II diabetes (T2DM), suggesting a shared pathway leading to HD. It underscores the role of insulin in HD pathogenesis, highlighting key factors such as insulin signaling, glucose metabolism, insulin resistance (IR), and the influence of adipocytes. Furthermore, the impact of adipose tissue accumulation, fatty acid metabolism, and pro-inflammatory cytokines like Tumor necrosis factor-α (TNF-α) on IR are discussed in the context of HD. Altered signaling pathways, disruptions in the endocrine system, liver inflammation, changes in muscle mass and composition, and modifications to the gut microbiota collectively contribute to the complex interplay linking cirrhosis and HD. This study highlights how important it is to identify and treat this complex condition in cirrhotic patients by thoroughly analyzing the link between cirrhosis, IR, and HD. It also emphasizes the vitality of targeted interventions. Cellular and molecular investigations into IR have revealed potential therapeutic targets for managing and preventing HD.

MicroRNAs in metabolic dysfunction-associated diseases: Pathogenesis and therapeutic opportunities

Metabolic dysfunction-associated diseases often refer to various diseases caused by metabolic problems such as glucose and lipid metabolism disorders. With the improvement of living standards, the increasing prevalence of metabolic diseases has become a severe public health problem, including metabolic dysfunction-associated steatotic liver disease (MASLD), alcohol-related liver disease (ALD), diabetes and obesity. These diseases are both independent and interdependent, with complex and diverse molecular mechanisms. Therefore, it is urgent to explore the molecular mechanisms and find effective therapeutic targets of these diseases. MicroRNAs (miRNAs) have emerged as key regulators of metabolic homoeostasis due to their multitargets and network regulatory properties within the past few decades. In this review, we discussed the latest progress in the roles of miRNA-mediated regulatory networks in the development and progression of MASLD, ALD, diabetes and obesity.

The role of perirenal adipose tissue deposition in chronic kidney disease progression: Mechanisms and therapeutic implications

Chronic kidney disease (CKD) represents a significant and escalating global health challenge, with morbidity and mortality rates rising steadily. Evidence increasingly implicates perirenal adipose tissue (PRAT) deposition as a contributing factor in the pathogenesis of CKD. This review explores how PRAT deposition may exert deleterious effects on renal structure and function. The anatomical proximity of PRAT to the kidneys not only potentially causes mechanical compression but also leads to the dysregulated secretion of adipokines and inflammatory mediators, such as adiponectin, leptin, visfatin, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and exosomes. Additionally, PRAT deposition may contribute to renal lipotoxicity through elevated levels of free fatty acids (FFA), triglycerides (TAG), diacylglycerol (DAG), and ceramides (Cer). PRAT deposition is also linked to the hyperactivation of the renin-angiotensin-aldosterone system (RAAS), which further exacerbates CKD progression. Recognizing PRAT deposition as an independent risk factor for CKD underscores the potential of targeting PRAT as a novel strategy for the prevention and management of CKD. This review further discusses interventions that could include measuring PRAT thickness to establish a baseline, managing metabolic risk factors that promote its deposition, and inhibiting key PRAT-induced signaling pathways.

Exercise as a tool to mitigate metabolic disease

Metabolic diseases, notably obesity and type 2 diabetes (T2D), have reached alarming proportions and constitute a significant global health challenge, emphasizing the urgent need for effective preventive and therapeutic strategies. In contrast, exercise training emerges as a potent intervention, exerting numerous positive effects on metabolic health through adaptations to the metabolic tissues. Here, we reviewed the major features of our current understanding with respect to the intricate interplay between metabolic diseases and key metabolic tissues, including adipose tissue, skeletal muscle, and liver, describing some of the main underlying mechanisms driving pathogenesis, as well as the role of exercise to combat and treat obesity and metabolic disease.

Buddleoside-rich Chrysanthemum indicum L. extract modulates macrophage-mediated inflammation to prevent metabolic syndrome induced by unhealthy diet

BACKGROUND

Metabolic syndrome (MetS) is a precursor to the development of many diseases (atherosclerosis, diabetes, etc.). It is marked by disruptions in glucose and lipid metabolism, along with hypertension. Numerous types of risk factors contribute to the development of the MetS, inflammation and insulin resistance are present throughout the metabolic abnormalities. Chrysanthemum indicum L. is a traditional Chinese plant used for both tea and medicine, known for its high content of total flavonoids, which are important secondary metabolites. Our research led to the extraction of a Buddleoside-Rich Chrysanthemum indicum L. extract (BUDE) which has demonstrated anti-inflammatory properties. Nonetheless, the specific role and mechanism of BUDE in preventing MetS remain unclear.

METHODS

The study initially evaluated the role of BUDE in preventing MetS. Subsequently, it investigated the anti-inflammatory properties of BUDE in the liver and pancreas in response to unhealthy diets. It then examined the level of insulin resistance and pancreatic β-cell function induced by inflammation. Additionally, an lipopolysaccharide (LPS)-induced macrophage inflammation model was used to further investigate the ameliorative effects of BUDE in inflammation.

RESULTS

BUDE has hypotensive, hypoglycemic and hypolipidemic effects. It can also resolve the imbalance between macrophage subpopulations, impede the triggering of the NF-κB signaling pathway, reduce the secretion of inflammatory mediators, ameliorate insulin resistance, and safeguard organs such as the liver and pancreas from inflammatory damage. These effects collectively contribute to preventing the development of MetS.

DISCUSSION

BUDE has the ability to modulate macrophage-mediated inflammation, leading to improved insulin resistance. Additionally, it delivers antihypertensive, hypoglycemic, and hypolipidemic effects, offering a potential for preventing MetS.

Unabsorbed Fecal Fat Content Correlates with a Reduction of Immunoglobulin a Coating of Gut Bacteria in High-Lard Diet-Fed Mice

SCOPE

Immunoglobulin A (IgA) selectively coats gut bacteria and contributes to regulatory functions in gastrointestinal inflammation and glucose metabolism. Excess intake of lard leads to decrease in the IgA coating of gut bacteria, although the underlying mechanisms remain unknown. This study validates how unabsorbed fat derived from a high-lard diet in the gut affects the IgA coating of bacteria, as assessed in mouse models using three types of dietary fat (lard, medium-, and long-chain triglycerides [MLCTs], and medium-chain triglycerides [MCTs]) exhibiting different digestibilities.

METHODS AND RESULTS

C57BL/6J mice are maintained on diets containing lard, MLCTs, or MCTs at 7% or 30% w/w for 10 weeks (n = 6 per group). The fecal fatty acid concentration is measured to quantify unabsorbed fat content. The ratio of IgA-coated bacteria to total bacteria (IgA coating ratio) in the feces is measured by flow cytometry. Compared to lard-fed mice, MLCT- and MCT-fed mice exhibit lower fecal concentrations of palmitic acid, stearic acid, and oleic acid and higher IgA coating ratios at both 7% and 30% dietary fat, and these parameters exhibit significant negative correlations.

CONCLUSION

Unabsorbed fat content in the gut may result in attenuated IgA coating of bacteria in high-lard diet-fed mice.

Inflammatory Bowel Disease Is an Independent Risk Factor for Metabolic Dysfunction-Associated Steatotic Liver Disease in Lean Individuals

BACKGROUND

Despite classical association between metabolic dysfunction-associated steatotic liver disease (MASLD) and obesity, there is increasing evidence on the development of MASLD in lean individuals. The aim of the study was to assess the prevalence and risk factors of MASLD and significant liver fibrosis in lean participants with inflammatory bowel disease (IBD).

METHODS

This was a cross-sectional, case-control study including 300 lean cases with IBD and 80 lean controls without IBD, matched by sex and age. All participants underwent a liver ultrasound, transient elastography, and laboratory tests.

RESULTS

The lean IBD group showed a significantly higher prevalence of MASLD compared with lean non-IBD group (21.3% vs 10%; P = .022), but no differences were observed in the prevalence of significant liver fibrosis (4.7% vs 0.0%; P = 1.000). No differences were found between the prevalence of MASLD in IBD and non-IBD participants who were overweight/obese (66.8% vs 70.8%; P = .442). In addition, the prevalence of MASLD was significantly higher in the overweight/obese IBD group compared with the lean IBD group (P < .001). IBD was an independent risk factor for MASLD in lean participants (odds ratio [OR], 2.71; 95% confidence interval [CI], 1.05-7.01; P = .04), after adjusting for classic metabolic risk factors and prior history of systemic steroid use. Nevertheless, no association between IBD related factors and MASLD was identified in lean IBD participants. When the overweight/obese and lean IBD groups with MASLD were compared, the overweight/obese IBD group with MASLD showed higher levels of the homeostatic model assessment of insulin resistance (OR, 1.49; 95% CI, 1.11-1.98; P = .007) and history of smoking (OR, 4.66; 95% CI, 1.17-18.49; P = .029).

CONCLUSIONS

MASLD prevalence was higher in the lean IBD group compared with lean non-IBD group, independent of classic metabolic risk factors.

Restoring SRSF3 in Kupffer cells attenuates obesity-related insulin resistance

BACKGROUND AND AIMS

In obesity, depletion of KCs expressing CRIg (complement receptor of the Ig superfamily) leads to microbial DNA accumulation, which subsequently triggers tissue inflammation and insulin resistance. However, the mechanism underlying obesity-mediated changes in KC complement immune functions is largely unknown.

APPROACH AND RESULTS

Using KC-specific deactivated Cas9 transgenic mice treated with guide RNA, we assessed the effects of restoring CRIg or the serine/arginine-rich splicing factor 3 (SRSF3) abundance on KC functions and metabolic phenotypes in obese mice. The impacts of weight loss on KC responses were evaluated in a diet switch mouse model. The role of SRSF3 in regulating KC functions was also evaluated using KC-specific SRSF3 knockout mice. Here, we report that overexpression of CRIg in KCs of obese mice protects against bacterial DNA accumulation in metabolic tissues. Mechanistically, SRSF3 regulates CRIg expression, which is essential for maintaining the CRIg+ KC population. During obesity, SRSF3 expression decreases, but it is restored with weight loss through a diet switch, normalizing CRIg+ KCs. KC SRSF3 is also repressed in obese human livers. Lack of SRSF3 in KCs in lean and obese mice decreases their CRIg+ population, impairing metabolic parameters. During the diet switch, the benefits of weight loss are compromised due to SRSF3 deficiency. Conversely, SRSF3 overexpression in obese mice preserves CRIg+ KCs and improves metabolic responses.

CONCLUSIONS

Restoring SRSF3 abundance in KCs offers a strategy against obesity-associated tissue inflammation and insulin resistance by preventing bacterial DNA accumulation.

Therapeutic potential of targeting protein tyrosine phosphatases in liver diseases

Protein tyrosine phosphorylation is a post-translational modification that regulates protein structure to modulate demic organisms' homeostasis and function. This physiological process is regulated by two enzyme families, protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). As an important regulator of protein function, PTPs are indispensable for maintaining cell intrinsic physiology in different systems, as well as liver physiological and pathological processes. Dysregulation of PTPs has been implicated in multiple liver-related diseases, including chronic liver diseases (CLDs), hepatocellular carcinoma (HCC), and liver injury, and several PTPs are being studied as drug therapeutic targets. Therefore, given the regulatory role of PTPs in diverse liver diseases, a collated review of their function and mechanism is necessary. Moreover, based on the current research status of targeted therapy, we emphasize the inclusion of several PTP members that are clinically significant in the development and progression of liver diseases. As an emerging breakthrough direction in the treatment of liver diseases, this review summarizes the research status of PTP-targeting compounds in liver diseases to illustrate their potential in clinical treatment. Overall, this review aims to support the development of novel PTP-based treatment pathways for liver diseases.

Twin Strep-Tag Modified CPT1A Mitochondrial Membrane Chromatography in Screening Lipid Metabolism Regulators

Mitochondrial Membrane Chromatography (MMC) is a bioaffinity chromatography technique developed to study the interaction between target proteins embedded in the mitochondrial membrane and their ligand compounds. However, the MMC stationary phases (MMSP) prepared by chemical immobilization are prone to nonspecific binding in candidate agent screening inevitably. To address these challenges, Twin Strep-Tag/Strep Tactin was employed to establish a specific affinity system in the present study. We prepared a carnitine palmitoyltransferase 1A (CPT1A) MMSP by specifically linking Strep-tactin-modified silica gel with the Twin Strep-Tag on the CPT1A-oriented mitochondrial membrane. This Twin Strep-Tag/Strep Tactin modified CPT1A/MMC method exhibited remarkably better retention behavior, longer stationary phase lifespan, and higher screening specificity compared with previous MMC systems with glutaraldehyde immobilization. We adopted the CPT1A-specific MMC system in screening CPT1A ligands from traditional Chinese medicines, and successfully identified novel candidate ligands: ononin, isoliquiritigenin, and aloe-emodin, from Glycyrrhiza uralensis Fisch and Senna tora (L.) Roxb extracts. Biological assessments illustrated that the compounds screened promote CPT1A enzyme activity without affecting CPT1A protein expression, as well as effectively reduce the lipid droplets and triglyceride levels in the high fat induction HepG2 cells. The results suggest that we have developed an MMC system, which is promising for studying the bioaffinity of mitochondrial membrane proteins to candidate compounds. This system provides a platform for a key step in mitochondrial medicine discovery, especially for bioactive molecule screening from complex herbal extracts.

MicroRNA-721 regulates gluconeogenesis via KDM2A-mediated epigenetic modulation in diet-induced insulin resistance in C57BL/6J mice

BACKGROUND

Aberrant gluconeogenesis is considered among primary drivers of hyperglycemia under insulin resistant conditions, with multiple studies pointing towards epigenetic dysregulation. Here we examine the role of miR-721 and effect of epigenetic modulator laccaic acid on the regulation of gluconeogenesis under high fat diet induced insulin resistance.

RESULTS

Reanalysis of miRNA profiling data of high-fat diet-induced insulin-resistant mice model, GEO dataset (GSE94799) revealed a significant upregulation of miR-721, which was further validated in invivo insulin resistance in mice and invitro insulin resistance in Hepa 1-6 cells. Interestingly, miR-721 mimic increased glucose production in Hepa 1-6 cells via activation of FOXO1 regulated gluconeogenic program. Concomitantly, inhibition of miR-721 reduced glucose production in palmitate induced insulin resistant Hepa 1-6 cells by blunting the FOXO1 induced gluconeogenesis. Intriguingly, at epigenetic level, enrichment of the transcriptional activation mark H3K36me2 got decreased around the FOXO1 promoter. Additionally, identifying targets of miR-721 using miRDB.org showed H3K36me2 demethylase KDM2A as a potential target. Notably, miR-721 inhibitor enhanced KDM2A expression which correlated with H3K36me2 enrichment around FOXO1 promoter and the downstream activation of the gluconeogenic pathway. Furthermore, inhibition of miR-721 in high-fat diet-induced insulin-resistant mice resulted in restoration of KDM2A levels, concomitantly reducing FOXO1, PCK1, and G6PC expression, attenuating gluconeogenesis, hyperglycemia, and improving glucose tolerance. Interestingly, the epigenetic modulator laccaic acid also reduced the hepatic miR-721 expression and improved KDM2A expression, supporting our earlier report that laccaic acid attenuates insulin resistance by reducing gluconeogenesis.

CONCLUSION

Our study unveils the role of miR-721 in regulating gluconeogenesis through KDM2A and FOXO1 under insulin resistance, pointing towards significant clinical and therapeutic implications for metabolic disorders. Moreover, the promising impact of laccaic acid highlights its potential as a valuable intervention in managing insulin resistance-associated metabolic diseases.

Endothelial-Specific Reduction in Arf6 Impairs Insulin-Stimulated Vasodilation and Skeletal Muscle Blood Flow Resulting in Systemic Insulin Resistance in Mice

BACKGROUND

Much of what we know about insulin resistance is based on studies from metabolically active tissues such as the liver, adipose tissue, and skeletal muscle. Emerging evidence suggests that the vascular endothelium plays a crucial role in systemic insulin resistance; however, the underlying mechanisms remain incompletely understood. Arf6 (ADP ribosylation factor 6) is a small GTPase that plays a critical role in endothelial cell function. Here, we tested the hypothesis that the deletion of endothelial Arf6 will result in systemic insulin resistance.

METHODS

We used mouse models of constitutive endothelial cell-specific Arf6 deletion (Arf6f/- Tie2Cre+) and tamoxifen-inducible Arf6 knockout (Arf6f/f Cdh5CreER+). Endothelium-dependent vasodilation was assessed using pressure myography. Metabolic function was assessed using a battery of metabolic assessments including glucose and insulin tolerance tests and hyperinsulinemic-euglycemic clamps. We used a fluorescence microsphere-based technique to measure tissue blood flow. Skeletal muscle capillary density was assessed using intravital microscopy.

RESULTS

Endothelial Arf6 deletion impaired insulin-stimulated vasodilation in white adipose tissue and skeletal muscle feed arteries. The impairment in vasodilation was primarily due to attenuated insulin-stimulated nitric oxide bioavailability but independent of altered acetylcholine-mediated or sodium nitroprusside-mediated vasodilation. Endothelial cell-specific deletion of Arf6 also resulted in systematic insulin resistance in normal chow-fed mice and glucose intolerance in high-fat diet-fed obese mice. The underlying mechanisms of glucose intolerance were reductions in insulin-stimulated blood flow and glucose uptake in the skeletal muscle and were independent of changes in capillary density or vascular permeability.

CONCLUSIONS

Results from this study support the conclusion that endothelial Arf6 signaling is essential for maintaining insulin sensitivity. Reduced expression of endothelial Arf6 impairs insulin-mediated vasodilation and results in systemic insulin resistance. These results have therapeutic implications for diseases that are associated with endothelial cell dysfunction and insulin resistance such as diabetes.

Notch signaling in adipose tissue macrophages prevents diet-induced inflammation and metabolic dysregulation

The importance of macrophages in adipose tissue (AT) homeostasis and inflammation is well established. However, the potential cues that regulate their function remain incompletely understood. To bridge this important gap, we sought to characterize novel pathways involved using a mouse model of diet-induced obesity. By performing transcriptomics analysis of AT macrophages (ATMs), we found that late-stage ATMs from high-fat diet mice presented with perturbed Notch signaling accompanied by robust proinflammatory and metabolic changes. To explore the hypothesis that the deregulated Notch pathway contributes to the development of AT inflammation and diet-induced obesity, we employed a genetic approach to abrogate myeloid Notch1 and Notch2 receptors. Our results revealed that the combined loss of Notch1 and Notch2 worsened obesity-related metabolic dysregulation. Body and AT weight gain was higher, blood glucose levels increased and metabolic parameters were substantially worsened in deficient mice fed high-fat diet. Moreover, serum insulin and leptin were elevated as were triglycerides. Molecular analysis of ATMs showed that deletion of Notch receptors escalated inflammation through the induction of an M1-like pro-inflammatory phenotype. Our findings thus support a protective role of myeloid Notch signaling in adipose tissue inflammation and metabolic dysregulation.

Association Between Insulin Resistance Indices and Liver Function Parameters Among Women With Polycystic Ovary Syndrome

OBJECTIVE

This study aimed to investigate whether polycystic ovary syndrome (PCOS) status changes the association between insulin resistance (IR) indices and liver function parameters among women.

METHODS

This is a cross-sectional, population-based study. We selected 1101 subjects aged ≥20 years from participants of Tehran Lipid and Glucose Study (TLGS). All of them had known the status of PCOS, and all variables were related to the IR indices and liver function parameters. The main outcome measures were TG/HDL-C and triglyceride-glucose (TyG) and liver function parameters (hepatic steatosis index [HSI], alanine transaminase [ALT] and aspartate transaminase [AST]).

RESULT

In the present study, there was no significant difference between the PCOS and the non-PCOS regarding the presence of liver function abnormalities. A model adjusted by age and BMI showed that the upper tertile of TyG index was positively associated with high AST (OR = 3.04 [95% CI: 1.20-7.68], p < 0.05), high ALT (4.76 [3.07-7.36], p < 0.05) and high HSI (8.44 [1.82-39.17], p < 0.05). Although the history of diabetes had a positive impact on elevated AST (1.66 [1.15, 2.40], p < 0.05), the third tertile of TG/HDL-C was associated with increased odds of elevated ALT (3.35 [2.21-5.06]) and HSI (6.55 [1.17-36.46]), whereas the second tertile of TG/HDL-C (OR = 2.65, CI 95%: 1.74-4.03) was also positively associated with elevated ALT. PCOS had no significant association with elevated liver function tests.

CONCLUSION

The highest tertile of TyG index and the TG/HDL-C ratio as a surrogate of IR might play a role in detecting abnormalities of liver function parameters among women. However, PCOS status cannot change the association between IR and liver dysfunction.

Genetic and Epigenetic Associations with Post-Transplant Diabetes Mellitus

Post-transplant diabetes mellitus (PTDM) is a common complication of solid organ transplantation. PTDM prevalence varies due to different diabetes definitions. Consensus guidelines for the diagnosis of PTDM have been published based on random blood glucose levels, glycated hemoglobin (HbA1c), and oral glucose tolerance test (OGTT). The task of diagnosing PTDM continues to pose challenges, given the potential for diabetes to manifest at different time points after transplantation, thus demanding constant clinical vigilance and repeated testing. Interpreting HbA1c levels can be challenging after renal transplantation. Pre-transplant risk factors for PTDM include obesity, sedentary lifestyle, family history of diabetes, ethnicity (e.g., African-Caribbean or South Asian ancestry), and genetic risk factors. Risk factors for PTDM include immunosuppressive drugs, weight gain, hepatitis C, and cytomegalovirus infection. There is also emerging evidence that genetic and epigenetic variation in the organ transplant recipient may influence the risk of developing PTDM. This review outlines many known risk factors for PTDM and details some of the pathways, genetic variants, and epigenetic features associated with PTDM. Improved understanding of established and emerging risk factors may help identify people at risk of developing PTDM and may reduce the risk of developing PTDM or improve the management of this complication of organ transplantation.

Highly crystalline cellulose microparticles from dealginated seaweed waste ameliorate high fat-sugar diet-induced hyperlipidemia in mice by modulating gut microbiota

The effects of seaweed cellulose (SC) on high fat-sugar diet (HFSD)-induced glucolipid metabolism disorders in mice and potential mechanisms were investigated. SC was isolated from dealginated residues of giant kelp (Macrocystis pyrifera), with a crystallinity index of 85.51 % and an average particle size of 678.2 nm. Administering SC to C57BL/6 mice at 250 or 500 mg/kg BW/day via intragastric gavage for six weeks apparently inhibited the development of HFSD-induced obesity, dyslipidemia, insulin resistance, oxidative stress and liver damage. Notably, SC intervention partially restored the structure and composition of the gut microbiota altered by the HFSD, substantially lowering the Firmicutes to Bacteroidetes ratio, and greatly increasing the relative abundance of Lactobacillus, Bifidobacterium, Oscillospira, Bacteroides and Akkermansia, which contributed to improved short-chain fatty acid (SCFA) production. Supplementing with a higher dose of SC led to more significant increases in total SCFA (67.57 %), acetate (64.56 %), propionate (73.52 %) and butyrate (66.23 %) concentrations in the rectal contents of HFSD-fed mice. The results indicated that highly crystalline SC microparticles could modulate gut microbiota dysbiosis and ameliorate HFSD-induced obesity and related metabolic syndrome in mice. Furthermore, particle size might have crucial impact on the prebiotic effects of cellulose as insoluble dietary fiber.

Potential Hepatoprotective Effect of Matricaria Pubescens on High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease in Rats

This study aimed to identify the phytochemical compounds of Matricaria pubescens by LC-MS/MS and evaluate the potential protective effect of its supplementation in high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) in adult rats through modulation of oxidative stress and histopathological changes. Twenty-four male rats were randomly divided into four groups. The first group served as control and received the standard diet. The second group (HFD) received a high-fat diet only (30 % of sheep fat). The third group's (control+MP) animals received a standard diet supplemented with 5 % M. pubescens (w/w). The fourth group (HFD+MP) received a high-fat diet supplemented with 5 % M. pubescens for 16 weeks. LC-MS/MS analysis showed that M. pubescens contains many phytochemical compounds. It was observed that the ethanolic extract of M. pubescens has a higher phenolic content than the aqueous extract. The supplementation of M. pubescens (5 % w/w) to HFD rats decreased significantly (p<0.01) body weight, liver and epididymal adipose tissue relative weights, glycemia, triglycerides (TG), insulin resistance, liver markers, TNF-α, malondialdehyde (MDA), protein carbonyl (PCO), advanced oxidation protein products (AOPP) level, and increased reduced glutathione (GSH) level, glutathione peroxidase (GPx), glutathione-S-transferase (GST), superoxide dismutase (SOD), and catalase activities as well as ameliorated histological alterations through the reduction hepatic lipid deposition and adipocytes hypertrophy compared to the HFD group. We conclude that M. pubescens powder may be effective for correcting hyperglycemia, hypertriglyceridemia, insulin resistance, and liver markers while decreasing inflammation and oxidative stress in the liver of high-fat diet-fed rats.

A Metabolomics Study of the Effects of Eleutheroside B on Glucose and Lipid Metabolism in a Zebrafish Diabetes Model

(1) Background: Diabetes is a common metabolic disease that seriously endangers human health. In the present study, we investigated the therapeutic effects of the active ingredient Eleutheroside B (EB) from the traditional Chinese medicine Eleutheroside on diabetes mellitus in a zebrafish model. Concomitant hepatic injury was also analysed, along with the study of possible molecular mechanisms using metabolomics technology. This work should provide some theoretical references for future experimental studies. (2) Methods: A zebrafish diabetes model was constructed by soaking in a 1.75% glucose solution and feeding a high-fat diet. The intervention drug groups were metformin (100 μg∙mL-1) and EB (50, 100, and 150 μg∙mL-1) via water-soluble exposure for 30 days. Glucose, TG, TC, LDL-C, and HDL-C were evaluated in different treatment groups. GLUT4 protein expression was also evaluated in each group, and liver injury was observed by HE staining. Metabolomics techniques were used to investigate the mechanism by which EB regulates endogenous markers and metabolic pathways during the development of diabetes. (3) Results: All EB treatment groups in diabetic zebrafish showed significantly reduced body mass index (BMI) and improved blood glucose and lipid profiles. EB was found to upregulate GLUT4 protein expression and ameliorate the liver injury caused by diabetes. Metabolomics studies showed that EB causes changes in the metabolic profile of diabetic zebrafish. These were related to the regulation of purine metabolism, cytochrome P450, caffeine metabolism, arginine and proline metabolism, the mTOR signalling pathway, insulin resistance, and glycerophospholipid metabolism. (4) Conclusions: EB has a hypoglycaemic effect in diabetic zebrafish as well as significantly improving disorders of glycolipid metabolism. The mechanism of action of EB may involve regulation of the mTOR signalling pathway, purine metabolism, caffeine metabolism, and glycerophospholipid metabolism.

Insulin resistance, and not β-cell impairment, mediates association between Mycobacterium tuberculosis sensitization and type II diabetes mellitus among US adults

Type 2 diabetes mellitus (T2DM) may be a long-term sequela of infection with Mycobacterium tuberculosis (M.tb) by mechanisms that remain to be fully explained. We evaluated association between M.tb sensitization and T2DM among U.S adults and, via formal mediation analysis, the extent to which this association is mediated by insulin resistance and/or β-cell failure. These evaluations accounted for demographic, socio-economic, behavioral and clinical characteristics. T2DM was assessed by fasting plasma glucose, 2-hour oral glucose tolerance testing and HbA1c; homoeostasis model assessment 2 (HOMA2) was used to estimate β-cell dysfunction (HOMA2-B) and insulin resistance (HOMA2-IR); while M.tb sensitization status was ascertained by tuberculin skin testing (TST). Exposure to M.tb was associated with increased risk for T2DM, likely driven by an increase in insulin resistance. Definitive prospective studies examining incident T2DM following tuberculosis are warranted.

Research in Context

What is already known about this subject?: Accumulating evidence suggests that pre-diabetes and new-onset type 2 diabetes mellitus (T2DM) may be a long-term complication of exposure to Mycobacterium tuberculosis ( M.tb ) via mechanisms that remain to be unraveled What is the key question?: To what extent do insulin resistance and β-cell failure mediate the association between M.tb sensitization with T2DM among US adults? What are the new findings?: M.tb sensitization is characterized by distinct glucose metabolic disturbances manifesting as increased risk of T2DM and isolated impaired fasting glucose (IFG) Insulin resistance, and not β-cell impairment, likely independently mediate the observed diabetogenic effects of M.tb sensitization How might this impact on clinical and/or public health practice in the foreseeable future?: If corroborated by prospective studies, both TB programs and individual clinical care must incorporate monitoring of serum glucose and long-term metabolic outcomesThis will be particularly urgent in sub-Saharan Africa and South-East Asia where scarce health resources coincide with overlapping endemic TB and epidemic T2DM.

Associations of HIV and prevalent type 2 diabetes mellitus in the context of obesity in South Africa

It is unclear how rising obesity among people with HIV (PWH) in sub-Saharan Africa (SSA) impacts their risk of type 2 diabetes mellitus (diabetes). Using a South African national cross-sectional sample of adult PWH and their peers without HIV (PWOH), we examined the associations between HIV and prevalent diabetes across the spectrum of body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WtHR). Analyses were sex stratified, and adjusted for age, sociodemographic and behavioral factors. The prevalence of diabetes among males was similar between PWH and PWOH, overall and at all levels of adiposity. In contrast, overall diabetes prevalence was higher among female PWOH than female PWH. However, there were differences according to adiposity such that, compared to female PWOH, relative diabetes prevalence in female PWH was reduced with obesity but accentuated with leanness. These differences in the relationship between adiposity and diabetes by HIV serostatus call for better mechanistic understanding of sex-specific adipose tissue biology in HIV in South Africa, and possibly in other HIV endemic settings in SSA.

Screening of CPT1A-Targeting Lipid Metabolism Modulators Using Mitochondrial Membrane Chromatography

Carnitine palmitoyltransferase 1A (CPT1A), which resides on the mitochondrial outer membrane, serves as the rate-limiting enzyme of fatty acid β-oxidation. Identifying the compounds targeting CPT1A warrants a promising candidate for modulating lipid metabolism. In this study, we developed a CPT1A-overexpressed mitochondrial membrane chromatography (MMC) to screen the compounds with affinity for CPT1A. Cells overexpressing CPT1A were cultured, and subsequently, their mitochondrial membrane was isolated and immobilized on amino-silica gel cross-linked by glutaraldehyde. After packing the mitochondrial membrane column, retention components of MMC were performed with LC/MS, whose analytic peaks provided structural information on compounds that might interact with mitochondrial membrane proteins. With the newly developed MMC-LC/MS approach, several Chinese traditional medicine extracts, such as Scutellariae Radix and Polygoni Cuspidati Rhizoma et Radix (PCRR), were analyzed. Five noteworthy compounds, baicalin, baicalein, wogonoside, wogonin, and resveratrol, were identified as enhancers of CPT1A enzyme activity, with resveratrol being a new agonist for CPT1A. The study suggests that MMC serves as a reliable screening system for efficiently identifying modulators targeting CPT1A from complex extracts.

Gut microbiota affects obesity susceptibility in mice through gut metabolites

Introduction

It is well-known that different populations and animals, even experimental animals with the same rearing conditions, differ in their susceptibility to obesity. The disparity in gut microbiota could potentially account for the variation in susceptibility to obesity. However, the precise impact of gut microbiota on gut metabolites and its subsequent influence on susceptibility to obesity remains uncertain.

Methods

In this study, we established obesity-prone (OP) and obesity-resistant (OR) mouse models by High Fat Diet (HFD). Fecal contents of cecum were examined using 16S rDNA sequencing and untargeted metabolomics. Correlation analysis and MIMOSA2 analysis were used to explore the association between gut microbiota and intestinal metabolites.

Results

After a HFD, gut microbiota and gut metabolic profiles were significantly different between OP and OR mice. Gut microbiota after a HFD may lead to changes in eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), a variety of branched fatty acid esters of hydroxy fatty acids (FAHFAs) and a variety of phospholipids to promote obesity. The bacteria g_Akkermansia (Greengene ID: 175696) may contribute to the difference in obesity susceptibility through the synthesis of glycerophosphoryl diester phosphodiesterase (glpQ) to promote choline production and the synthesis of valyl-tRNA synthetase (VARS) which promotes L-Valine degradation. In addition, gut microbiota may affect obesity and obesity susceptibility through histidine metabolism, linoleic acid metabolism and protein digestion and absorption pathways.

Research Progress on the Effect and Mechanism of Tea Products with Different Fermentation Degrees in Regulating Type 2 Diabetes Mellitus

A popular non-alcoholic beverage worldwide, tea can regulate blood glucose levels, lipid levels, and blood pressure, and may even prevent type 2 diabetes mellitus (T2DM). Different tea fermentation levels impact these effects. Tea products with different fermentation degrees containing different functional ingredients can lower post-meal blood glucose levels and may prevent T2DM. There are seven critical factors that shed light on how teas with different fermentation levels affect blood glucose regulation in humans. These factors include the inhibition of digestive enzymes, enhancement of cellular glucose uptake, suppression of gluconeogenesis-related enzymes, reduction in the formation of advanced glycation end products (AGEs), inhibition of dipeptidyl peptidase-4 (DPP-4) activity, modulation of gut flora, and the alleviation of inflammation associated with oxidative stress. Fermented teas can be used to lower post-meal blood glucose levels and can help consumers make more informed tea selections.

Pathogenesis and comprehensive treatment strategies of sarcopenia in elderly patients with type 2 diabetes mellitus

Sarcopenia and diabetes are two age-related diseases that are common in the elderly population, and have a serious effect on their general health and quality of life. Sarcopenia refers to the progressive loss of muscle mass, strength and function, whereas diabetes is a chronic disease characterized by elevated blood sugar levels. The comorbidity of sarcopenia and diabetes is particularly concerning, as people with diabetes have a higher risk of developing sarcopenia due to the combination of insulin resistance, chronic inflammation and reduced physical activity. In contrast, sarcopenia destroyed blood sugar control and exacerbated the development of people with diabetes, leading to the occurrence of a variety of complications. Fortunately, there are a number of effective treatment strategies for sarcopenia in people with diabetes. Physical exercise and a balanced diet with enough protein and nutrients have been proved to enhance the muscular quality and strength of this population. Additionally, pharmacological therapies and lifestyle changes can optimize blood sugar control, which can prevent further muscle loss and improve overall health outcomes. This review aims to summarize the pathogenesis and comprehensive treatment strategies of sarcopenia in elderly patients with type 2 diabetes, which help healthcare professionals recognize their intimate connection and provide a new vision for the treatment of diabetes and its complications in this population. Through early identification and comprehensive treatment, it is possible to improve the muscle function and general quality of life of elderly with diabetes and sarcopenia.

Associations of HIV and prevalent type 2 diabetes mellitus in the context of obesity in South Africa

Background

It is unclear how rising obesity among people with HIV (PWH) impacts their risk of type 2 diabetes mellitus (diabetes). We examined associations between HIV, prevalent diabetes and adiposity among South African PWH and their peers without HIV (PWOH).

Methods

HIV status was ascertained by antibody testing. Diabetes was defined as current use of oral hypoglycemics, insulin, and/or HbA1c ≥6.5%. Adiposity was measured by body mass index (BMI), waist circumference and waist-to-height ratio. Their associations were examined using sex-stratified multivariable fractional polynomial generalized linear models, reporting adjusted prevalence and prevalence ratios (adjPR).

Results

The mean age among 1,254 PWH and 4,381 PWOH was 41 years (95%CI 28, 56). The prevalence of diabetes among males was similar between PWH [11.3% (7.1, 15.5)] and PWOH [9.8% (8.5, 11.1); p=0.740]. By contrast, diabetes prevalence was higher among female PWOH [15.7% (14.4, 17.0)] than female PWH [10.5 (8.3, 12.8)%; adjPR: 0.67 (0.51, 0.82); p<0.001]. This difference was accentuated with obesity but reversed with leanness. At BMI ≥25 kg/m2, female PWH had lower diabetes prevalence [adjPR: 0.58 (0.41, 0.76); p<0.001] than female PHIV. In contrast, at BMI <18 kg/m2, female PWH had higher prevalence [adjPR: 1.72 (-1.53, 4.96); p=0.756] than female PWOH.

Conclusion

We found sex-specific differences in the relationship between adiposity and diabetes prevalence by HIV serostatus in South Africa. Notably, females living with obesity and HIV had lower prevalence of diabetes than females living with obesity and without HIV, which may have particular implications for diabetes prevention programs in the region.

Insight into the Predictive Power of Surrogate Diagnostic Indices for Identifying Individuals with Metabolic Syndrome

BACKGROUND

This study aimed to assess the diagnostic capability of insulin surrogate measurements in identifying individuals with metabolic syndrome (MetS) and propose applicable indices derived from fasting values, particularly in large study populations.

METHODS

Data were collected from the datasets of the Surveillance of Risk Factors of NCDs in Iran Study (STEPS). MetS was defined based on the National Cholesterol Education Program (NCEP) criteria. Various insulin surrogate indices, including Homeostasis Model Assessment (HOMA), Quantitative Insulin Sensitivity Check Index (QUICKI), Fasting glucose to insulin ratio (FGIR), Reynaud, Reciprocal insulin, McAuley, Metabolic Score for Insulin Resistance (METS-IR), Triglyceride-glucose index (TyG), TG/ HDL-C, TG/ BMI, and TG/ WC ratio were assessed. Receiver Operating Characteristic (ROC) curves were used to assess pathologic conditions and determine the optimal cut-off through the highest score of the Youden index. Also, Area Under the Curve (AUC) values were established for each index totally and according to sex, age, and BMI differences.

RESULTS

The study population consisted of 373 individuals (49.9% women; 75.1% middle age, 39.1% obese, and 27.3% overweight), of whom 117 (31.4%) had MetS. The METS-IR (AUC: 0.856; 95% CI: 0.817-0.895), TG/ HDL-C (AUC: 0.820; 95% CI: 0.775-0.886), TyG (AUC: 0.808; 95% CI: 0.759-0.857), and McAuley (AUC: 0.804; 95% CI: 0.757-0.852) indices provided the greatest AUC respectively for detection of MetS. The values of AUC for all the indices were higher in men than women. This trend was consistent after data stratification based on BMI categories, middle age, and senile individuals.

CONCLUSION

The present study indicated that indices of insulin, including METS-IR, TG/HDLC, TyG, and McAuley, have an equal or better capacity in determining the risk of MetS than HOMA-IR, are capable of identifying individuals with MetS and may provide a simple approach for identifying populations at risk of insulin resistance.

The Effects of 1-Kestose on the Abundance of Inflammation-Related Gene mRNA in Adipose Tissue and the Gut Microbiota Composition in Rats Fed a High-Fat Diet

Chronic inflammation in adipose tissue is thought to contribute to insulin resistance, which involves the gut microbiota. Our previous studies have demonstrated that ingestion of 1-kestose can alter the gut microbiota composition, increase cecal butyrate levels, and improve insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Additionally, we found that 1-kestose supplementation ameliorated insulin resistance in obese rat models fed a high-fat diet (HFD), although the effects of 1-kestose on the abundance of inflammation-related gene in adipose tissue and gut microbiota composition in these rats were not explored. This study aimed to investigate the impact of 1-kestose on these parameters in HFD-fed rats, compared to OLETF rats. Male Sprague-Dawley rats were divided into two dietary groups, control or HFD, for 19 wk. Each group was further subdivided to receive either tap water or tap water supplemented with 2% (w/v) 1-kestose throughout the study. We evaluated gene expression in adipose tissue, as well as short-chain fatty acids (SCFAs) levels and microbial composition in the cecum contents. 1-Kestose intake restored the increased relative abundance of tumor necrosis factor (Tnf) mRNA in adipose tissue and the reduced level of butyrate in the cecum contents of HFD-fed rats to those observed in control diet-fed rats. Additionally, 1-kestose consumption changed the composition of the gut microbiota, increasing Butyricicoccus spp., decreasing UGC-005 and Streptococcus spp., in the cecum contents of HFD-fed rats. Our findings suggest that 1-kestose supplementation reduces adipose tissue inflammation and increases butyrate levels in the gut of HFD-fed rats, associated with changes in the gut microbiota composition, distinct from those seen in OLETF rats.

Post-stroke immunosuppression: Exploring potential implications beyond infections

Stroke is a leading cause of mortality and disability. It occurs when cerebral blood flow is disrupted via vascular occlusion or rupture, causing tissue damage. Research has extensively examined the role of the immune response in stroke pathophysiology, focusing on infiltrated immune cells and inflammatory molecules. However, the stroke's impact on immune physiology remains underexplored. While initially stroke triggers the activation of peripheral inflammation, a subsequent profound immunosuppression occurs in a matter of hours/days. This response, potentially shielding the brain from excessive inflammation, significantly affects stroke patients. Beyond rendering patients more susceptible to infections, immunosuppression generates diverse consequences by disrupting immune system functions that are crucial for organ homeostasis. This review explores the effects of immunosuppression on stroke patients, shedding light on potential issues in immune organs such as the spleen and bone marrow, as well as non-immune organs like the small intestine, liver and heart. By synthesizing existing literature and offering additional insights, this manuscript highlights the multifaceted impact of post-stroke immunosuppression.

Value of C-Reactive Protein-Triglyceride Glucose Index in Predicting Cancer Mortality in the General Population: Results from National Health and Nutrition Examination Survey

BACKGROUND

Cancer is one of the leading causes of death. The current work aims to investigate the association between C-reactive protein-triglyceride glucose index (CTI) and the risk of incident cancer mortality and to evaluate the usefulness of CTI to refine the risk stratification of cancer mortality.

METHODS

The study enrolled 19,957 subjects from American National Health and Nutrition Examination Survey. CTI was defined as 0.412*Ln(CRP) + ln[T.G. (mg/dL) × FPG (mg/dL)/2]. Cox regression was performed to investigate the association.

RESULTS

During a follow-up of 215417.52 person-years, 736 subjects died due to malignant tumors, and the incidence of cancer mortality was 3.42 per 1,000 person-years. Kaplan-Meier curve revealed that the fourth quartile group had the lowest cancer mortality-free rate (Log-Rank p < 0.001). After full adjustment, each SD increase of CTI cast a 32.7% additional risk of incident cancer mortality. Furthermore, cancer mortality risk elevated proportionally with the increase of CTI. Finally, ROC and reclassification analyses supported the usefulness of CTI in improving the risk stratification of incident cancer mortality.

CONCLUSION

The study revealed a significant association between CTI and cancer mortality risk, suggesting the value of CTI in improving the risk stratification of incident cancer mortality. KEY MESAGESC-reactive protein-triglyceride glucose index (CTI) is positively associated with cancer mortality risk in the general population.The association was linear in the whole range of CTI.CTI could improve the risk prediction of cancer mortality in the general population.

Parabacteroides distasonis ameliorates insulin resistance via activation of intestinal GPR109a

Gut microbiota plays a key role in insulin resistance (IR). Here we perform a case-control study of Chinese adults (ChiCTR2200065715) and identify that Parabacteroides distasonis is inversely correlated with IR. Treatment with P. distasonis improves IR, strengthens intestinal integrity, and reduces systemic inflammation in mice. We further demonstrate that P. distasonis-derived nicotinic acid (NA) is a vital bioactive molecule that fortifies intestinal barrier function via activating intestinal G-protein-coupled receptor 109a (GPR109a), leading to ameliorating IR. We also conduct a bioactive dietary fiber screening to induce P. distasonis growth. Dendrobium officinale polysaccharide (DOP) shows favorable growth-promoting effects on P. distasonis and protects against IR in mice simultaneously. Finally, the reduced P. distasonis and NA levels were also validated in another human type 2 diabetes mellitus cohort. These findings reveal the unique mechanisms of P. distasonis on IR and provide viable strategies for the treatment and prevention of IR by bioactive dietary fiber.

Association of adiposity indices with cardiometabolic multimorbidity among 101,973 chinese adults: a cross-sectional study

BACKGROUND

Cardiometabolic multimorbidity (CMM) and obesity represent two major health problems. The relationship between adiposity indices and CMM, however, remains understudied. This study aimed to investigate the associations of body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), a body shape index (ABSI), body roundness index (BRI), and conicity index (CI) with CMM among Chinese adults.

METHODS

Data of 101,973 participants were collected from a population-based screening project in Southern China. CMM was defined as having two or more of the following diseases: coronary heart disease, stroke, hypertension, and diabetes. The relationship between the six adiposity indices and CMM was investigated by multivariate logistic regression and restricted cubic splines. Receiver operator characteristic curve, C-statistic and net reclassification index were used to estimate the discriminative and incremental values of adiposity indices on CMM.

RESULTS

Logistic regression models showed the six adiposity indices were all significantly associated with the odds of CMM with non-linear relationships. For per SD increment, WC (Odds ratio [OR]: 1.66; 95% confidence interval (CI): 1.62-1.70) and WHtR (OR, 1.61; 95% CI, 1.58-1.65) were more significantly associated with a higher prevalence of CMM than BMI (OR, 1.55; 95% CI, 1.52-1.58) (all P < 0.05). In addition, WC, WHtR, and BRI displayed significantly better performance in detecting CMM compared with BMI (all P < 0.05). Their respective area under the curve (AUC) values were 0.675 (95% CI: 0.670-0.680), 0.679 (95% CI: 0.675-0.684), and 0.679 (95% CI: 0.675-0.684), while BMI yielded an AUC of 0.637 (95% CI: 0.632-0.643). These findings hold true across all subgroups based on sex and age. When Adding WC, WHtR, or BRI to a base model, they all provided larger incremental values for the discrimination of CMM compared with BMI (all P < 0.05).

CONCLUSIONS

Adiposity indices were closely associated with the odds of CMM, with WC and WHtR demonstrating stronger associations than BMI. WC, WHtR, and BRI were superior to BMI in discriminative ability for CMM. Avoidance of obesity (especially abdominal obesity) may be the preferred primary prevention strategy for CMM while controlling for other major CMM risk factors.

Ube2L6 Promotes M1 Macrophage Polarization in High-Fat Diet-Fed Obese Mice via ISGylation of STAT1 to Trigger STAT1 Activation

INTRODUCTION

In obesity-related type 2 diabetes mellitus (T2DM), M1 macrophages aggravate chronic inflammation and insulin resistance. ISG15-conjugation enzyme E2L6 (Ube2L6) has been demonstrated as a promoter of obesity and insulin resistance. This study investigated the function and mechanism of Ube2L6 in M1 macrophage polarization in obesity.

METHODS

Obesity was induced in Ube2L6AKO mice and age-matched Ube2L6flox/flox control mice by high-fat diet (HFD). Stromal vascular cells were isolated from the epididymal white adipose tissue of mice. Polarization induction was performed in mouse bone marrow-derived macrophages (BMDMs) by exposure to IFN-γ, lipopolysaccharide, or IL-4. F4/80 expression was assessed by immunohistochemistry staining. Expressions of M1/M2 macrophage markers and target molecules were determined by flow cytometry, RT-qPCR, and Western blotting, respectively. Protein interaction was validated by co-immunoprecipitation (Co-IP) assay. The release of TNF-α and IL-10 was detected by ELISA.

RESULTS

The polarization of pro-inflammatory M1 macrophages together with an increase in macrophage infiltration was observed in HFD-fed mice, which could be restrained by Ube2L6 knockdown. Additionally, Ube2L6 deficiency triggered the repolarization of BMDMs from M1 to M2 phenotypes. Mechanistically, Ube2L6 promoted the expression and activation of signal transducer and activator of transcription 1 (STAT1) through interferon-stimulated gene 15 (ISG15)-mediated ISGlylation, resulting in M1 macrophage polarization.

CONCLUSION

Ube2L6 exerts as an activator of STAT1 via post-translational modification of STAT1 by ISG15, thereby triggering M1 macrophage polarization in HFD-fed obese mice. Overall, targeting Ube2L6 may represent an effective therapeutic strategy for ameliorating obesity-related T2DM.

The Intestinal Microbiome and the Metabolic Syndrome-How Its Manipulation May Affect Metabolic-Associated Fatty Liver Disease (MAFLD)

Metabolic-associated fatty liver disease (MAFLD) is now the predominant liver disease worldwide consequent to the epidemic of obesity. The intestinal microbiome (IM), consisting of the bacteria, fungi, archaea, and viruses residing in the gastrointestinal tract, plays an important role in human metabolism and preserving the epithelial barrier function. Disturbances in the IM have been shown to influence the development and progression of MAFLD and play a role in the development of metabolic syndrome (MS). The main treatment for MAFLD involves lifestyle changes, which also influence the IM. Manipulation of the IM by fecal microbial transplantation (FMT) has been approved for the treatment of recurrent Closteroides difficile infection. This may be administered by endoscopic administration from the lower or upper GI tract. Other methods of administration include nasogastric tube, enema, and oral capsules of stool from healthy donors. In this narrative review, we elaborate on the role of the IM in developing MS and MAFLD and on the current experience with IM modulation by FMT on MAFLD.

Connecting the dots in the associations between diet, obesity, cancer, and microRNAs

The prevalence of obesity has reached pandemic levels worldwide, leading to a lower quality of life and higher health costs. Obesity is a major risk factor for noncommunicable diseases, including cancer, although obesity is one of the major preventable causes of cancer. Lifestyle factors, such as dietary quality and patterns, are also closely related to the onset and development of obesity and cancer. However, the mechanisms underlying the complex association between diet, obesity, and cancer remain unclear. In the past few decades, microRNAs (miRNAs), a class of small non-coding RNAs, have been demonstrated to play critical roles in biological processes such as cell differentiation, proliferation, and metabolism, highlighting their importance in disease development and suppression and as therapeutic targets. miRNA expression levels can be modulated by diet and are involved in cancer and obesity-related diseases. Circulating miRNAs can also mediate cell-to-cell communications. These multiple aspects of miRNAs present challenges in understanding and integrating their mechanism of action. Here, we introduce a general consideration of the associations between diet, obesity, and cancer and review the current knowledge of the molecular functions of miRNA in each context. A comprehensive understanding of the interplay between diet, obesity, and cancer could be valuable for the development of effective preventive and therapeutic strategies in future.

From Xiaoke to diabetes mellitus: a review of the research progress in traditional Chinese medicine for diabetes mellitus treatment

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemia resulting from insulin secretion defects or insulin resistance. The global incidence of DM has been gradually increasing due to improvements in living standards and changes in dietary habits, making it a major non-communicable disease that poses a significant threat to human health and life. The pathogenesis of DM remains incompletely understood till now, and current pharmacotherapeutic interventions are largely inadequate, resulting in relapses and severe adverse reactions. Although DM is not explicitly mentioned in traditional Chinese medicine (TCM) theory and clinical practice, it is often classified as "Xiaoke" due to similarities in etiology, pathogenesis, and symptoms. With its overall regulation, multiple targets, and personalized medication approach, TCM treatment can effectively alleviate the clinical manifestations of DM and prevent or treat its complications. Furthermore, TCM exhibits desirable therapeutic effects with minimal side effects and a favorable safety profile. This paper provides a comprehensive comparison and contrast of Xiaoke and DM by examining the involvement of TCM in their etiology, pathogenesis, treatment guidelines, and other relevant aspects based on classical literature and research reports. The current TCM experimental research on the treatment of DM by lowering blood glucose levels also be generalized. This innovative focus not only illuminates the role of TCM in DM treatment, but also underscores the potential of TCM in DM management.

Islr regulates insulin sensitivity by interacting with Psma4 to control insulin receptor alpha levels in obese mice

Insulin resistance is the leading cause of type 2 diabetes (T2D), and dysfunctional insulin receptor signaling is a major manifestation of this insulin resistance. In T2D, the corresponding insulin receptor levels are aberrantly down-regulated, which is one of the major factors underlying obesity-induced insulin resistance in adipose tissue. However, the precise mechanism of insulin receptor impairment in obese individuals remains unclear. In the current study, we established that immunoglobulin superfamily containing leucine-rich repeat (Islr) is highly expressed in adipocytes of mice fed a high-fat diet. We further demonstrated that Islr mediates the ubiquitin-independent proteasomal degradation of insulin receptor alpha (Insrα) by specifically interacting with proteasome subunit alpha type 4 (Psma4). Islr knockout increased the corresponding Insrα subunit levels and enhanced insulin sensitivity in adipocytes, ultimately improving systemic metabolism. Further, siRNA-mediated down-regulation of Islr expression in the white adipose tissue of obese mice increased insulin sensitivity. Overall, Islr regulates insulin sensitivity by interacting with Psma4 to control the ubiquitin-independent proteasomal degradation of Insrα in obese mice, indicating that Islr may be a potential therapeutic target for ameliorating insulin resistance.

Signaling pathways and intervention for therapy of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) represents one of the fastest growing epidemic metabolic disorders worldwide and is a strong contributor for a broad range of comorbidities, including vascular, visual, neurological, kidney, and liver diseases. Moreover, recent data suggest a mutual interplay between T2DM and Corona Virus Disease 2019 (COVID-19). T2DM is characterized by insulin resistance (IR) and pancreatic β cell dysfunction. Pioneering discoveries throughout the past few decades have established notable links between signaling pathways and T2DM pathogenesis and therapy. Importantly, a number of signaling pathways substantially control the advancement of core pathological changes in T2DM, including IR and β cell dysfunction, as well as additional pathogenic disturbances. Accordingly, an improved understanding of these signaling pathways sheds light on tractable targets and strategies for developing and repurposing critical therapies to treat T2DM and its complications. In this review, we provide a brief overview of the history of T2DM and signaling pathways, and offer a systematic update on the role and mechanism of key signaling pathways underlying the onset, development, and progression of T2DM. In this content, we also summarize current therapeutic drugs/agents associated with signaling pathways for the treatment of T2DM and its complications, and discuss some implications and directions to the future of this field.

Endothelial specific reduction in Arf6 impairs insulin-stimulated vasodilation and skeletal muscle blood flow resulting in systemic insulin resistance

Background

Much of what we know about insulin resistance is based on studies from metabolically active tissues such as liver, adipose tissue, and skeletal muscle. Emerging evidence suggests that the vascular endothelium plays a crucial role in systemic insulin resistance, however, the underlying mechanisms remain incompletely understood. ADP ribosylation factor 6 (Arf6) is a small GTPase that plays a critical role in endothelial cell (EC) function. Here, we tested the hypothesis that the deletion of endothelial Arf6 will result in systemic insulin resistance.

Methods

We used mouse models of constitutive EC-specific Arf6 deletion (Arf6 f/- Tie2Cre) and tamoxifen inducible Arf6 knockout (Arf6 f/f Cdh5Cre). Endothelium-dependent vasodilation was assessed using pressure myography. Metabolic function was assessed using a battery of metabolic assessments including glucose- and insulin-tolerance tests and hyperinsulinemic-euglycemic clamps. A fluorescence microsphere-based technique was used to measure tissue blood flow. Intravital microscopy was used to assess skeletal muscle capillary density.

Results

Endothelial Arf6 deletion impaired insulin-stimulated vasodilation in white adipose tissue (WAT) and skeletal muscle feed arteries. The impairment in vasodilation was primarily due to attenuated insulin-stimulated nitric oxide (NO) bioavailability but independent of altered acetylcholine- or sodium nitroprusside-mediated vasodilation. In vitro Arf6 inhibition resulted in suppressed insulin stimulated phosphorylation of Akt and endothelial NO synthase. Endothelial cell-specific deletion of Arf6 also resulted in systematic insulin resistance in normal chow fed mice and glucose intolerance in high fat diet fed obese mice. The underlying mechanisms of glucose intolerance were reductions in insulin-stimulated blood flow and glucose uptake in the skeletal muscle and were independent of changes in capillary density or vascular permeability.

Conclusion

Results from this study support the conclusion that endothelial Arf6 signaling is essential for maintaining insulin sensitivity. Reduced expression of endothelial Arf6 impairs insulin-mediated vasodilation and results in systemic insulin resistance. These results have therapeutic implications for diseases that are associated with endothelial cell dysfunction and insulin resistance such as diabetes.