Modulation Of Insulin Resistance Research Articles

Long-Term Aerobic Exercise Enhances Hepatoprotection in MAFLD by Modulating Exosomal miR-324 via ROCK1.

Insulin resistance (IR) is central to the progression of non-alcoholic fatty liver disease (MAFLD). While aerobic exercise reduces hepatic fat and enhances insulin sensitivity, the specific mechanisms-particularly those involving exosomal pathways-are not fully elucidated. Exosomes were isolated from 15 MAFLD patients' plasma following the final session of a 12-week aerobic exercise intervention. Liver fat content was measured using MRI-PDFF, and metabolic parameters were assessed via OGTT, HOMA-IR, QUICKI, and VO2 max. Co-culture experiments evaluated the effects of exercise-derived exosomes on IR signaling pathways. miRNA microarray analysis identified miR-324, which was quantified in high-fat diet (HFD) mice with and without exercise and compared between athletes and sedentary controls. Functional assays assessed miR-324's role in glucose and lipid metabolism, while luciferase reporter and Western blot assays confirmed ROCK1 as its direct target. Aerobic exercise significantly reduced liver fat and improved insulin sensitivity in both MAFLD patients and HFD mice. Notably, exosomal miR-324 levels were lower in athletes than sedentary controls, indicating an inverse association with insulin sensitivity. Post-exercise, precursor and mature miR-324 increased in adipose tissue and decreased in muscle, suggesting its adipose origin and inverse regulation. Functional assays demonstrated that miR-324 modulates insulin resistance by targeting ROCK1. Exercise-induced exosomal miR-324 from adipose tissue targets ROCK1, revealing a novel mechanism by which aerobic exercise confers hepatoprotection against insulin resistance in MAFLD. These findings enhance our understanding of how exercise influences metabolic health and may inform future therapeutic strategies for managing MAFLD and related conditions.

Mangiferin ameliorates polycystic ovary syndrome in rats by modulating insulin resistance, gut microbiota, and ovarian cell apoptosis.

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder characterized by hyperandrogenism, prolonged anovulation and polycystic ovaries. However, there are no effective interventions to treat this disorder. As previously shown, mangiferin modulated the AMPK and NLRP3 signal pathways to alleviate nonalcoholic fatty liver disease (NAFLD). In recent years, mangiferin has emerged as a promising drug candidate for treating metabolic diseases. In this study, we evaluated the effects of mangiferin on a letrozole (LET) combined with high-fat diet (HFD)-induced PCOS rat model through estrous cycle detection, serum/tissue biochemical analysis, and hematoxylin and eosin (HE) staining of ovarian tissue. The mechanisms of mangiferin's effects on PCOS rats were analyzed using 16S rRNA sequencing, RNA-seq, western blotting (WB), and immunohistochemical (IHC) staining. Our results displayed that mangiferin showed a promising effect in PCOS rats. It improved lipid metabolism, glucose tolerance, insulin resistance, hormonal imbalance, ovarian dysfunction, and adipocyte abnormalities. RNA-seq analysis indicated that mangiferin may be involved in several signal pathways, including apoptosis, necrosis, and inflammation. Furthermore, western blot and immunohistochemical staining demonstrated that mangiferin regulates Caspase-3 and Cytc, exhibiting anti-apoptotic activity in the ovaries. Additionally, mangiferin significantly altered the gut microbiota community of PCOS rats, changing the abundance of firmicutes, bacteroidota, proteobacteria, and actinobacteria at the phylum level and the abundance of Blautia, Coprococcus, Roseburia, and Pseudomonas at the genus level. In conclusion, mangiferin is a promising and novel therapeutic agent for PCOS as it ameliorates insulin resistance, gut microbiota and ovarian cell apoptosis.

Biomolecules of Adipose Tissue in Atherosclerotic Plaques of Men With Coronary Atherosclerosis.

To study metabolic molecules (adiponectin, adipsin, resistin, glucagon-like peptide-1 (GLP-1), glucagon, secretin) of adipose tissue in atherosclerotic plaques (AP) and their associations with AP instability in men with coronary atherosclerosis. Metabolic molecules (adipocytokines and metabolic hormones) of adipose tissue can act as enzymes, hormones or growth factors in modulating insulin resistance and lipid and glucose metabolism and indirectly influence the course of the atherosclerotic process. This study included 48 men from whom 139 coronary artery (CA) samples were collected during coronary artery bypass grafting, after obtaining the informed consent. According to the histological conclusion, 84 (60.4%) CA plaques were stable, 44 (31.7%) were unstable, and 11 histological samples had a conditionally unchanged CA intima (7.9%). The concentrations of adiponectin, adipsin, resistin, GLP-1, glucagon, and secretin were measured in AP homogenates by multiplex analysis using the Human Metabolic Hormone V3 panel (MILLIPLEX, Germany). During the study, demographic and anthropometric characteristics, medical history, and presence of chronic diseases were recorded. The glucagon concentration in the conditionally unchanged intima was 16.7% lower and in the fragments of unstable atherosclerotic plaques 41.2% lower than in fragments of stable APs. However, the glucagon concentration in stable APs was 28% higher than in unstable APs. The secretin concentration in the conditionally unchanged intima was also lower than in stable APs by 41.2%, while in stable APs, the secretin concentration was 20% higher than in unstable APs. The adiponectin concentrations were directly correlated with serum high-density lipoprotein cholesterol (HDL-C) concentrations (r=0.286; p=0.002), while the secretin concentrations were inversely correlated with serum HDL-C concentrations (r= -0.199; p=0.038). The probability of having an unstable AP (in relation to conditionally unchanged intima) increases by 35.8% with an increase in the AP glucagon concentration by 1 pg/mg protein. The probability of having a stable AP (in relation to unchanged intima) increases by 29.4% with an increase in the AP glucagon concentration by 1 pg/mg protein and by 10.1% with an increase in the AP secretin concentration by 1 pg/mg protein. The AP adiponectin concentration directly correlates and the AP secretin concentration inversely correlates with the serum concentration of HDL-C. The presence of both stable and unstable APs is directly associated with the AP glucagon concentration in men with coronary atherosclerosis. The AP secretin concentration is directly associated with plaque stability in men with coronary atherosclerosis. Further thorough study of the identified markers in atherosclerotic lesions will allow using them as potential targets for therapy.

RNA-binding protein GIGYF2 orchestrates hepatic insulin resistance through STAU1/PTEN-mediated disruption of the PI3K/AKT signaling cascade

BackgroundObesity is well-established as a significant contributor to the development of insulin resistance (IR) and diabetes, partially due to elevated plasma saturated free fatty acids like palmitic acid (PA). Grb10-interacting GYF Protein 2 (GIGYF2), an RNA-binding protein, is widely expressed in various tissues including the liver, and has been implicated in diabetes-induced cognitive impairment. Whereas, its role in obesity-related IR remains uninvestigated.MethodsIn this study, we employed palmitic acid (PA) exposure to establish an in vitro IR model in the human liver cancer cell line HepG2 with high-dose chronic PA treatment. The cells were stained with fluorescent dye 2-NBDG to evaluate cell glucose uptake. The mRNA expression levels of genes were determined by real-time qRT-PCR (RT-qPCR). Western blotting was employed to examine the protein expression levels. The RNA immunoprecipitation (RIP) was used to investigate the binding between protein and mRNA. Lentivirus-mediated gene knockdown and overexpression were employed for gene manipulation. In mice, an IR model induced by a high-fat diet (HFD) was established to validate the role and action mechanisms of GIGYF2 in the modulation of HFD-induced IR in vivo.ResultsIn hepatocytes, high levels of PA exposure strongly trigger the occurrence of hepatic IR evidenced by reduced glucose uptake and elevated extracellular glucose content, which is remarkably accompanied by up-regulation of GIGYF2. Silencing GIGYF2 ameliorated PA-induced IR and enhanced glucose uptake. Conversely, GIGYF2 overexpression promoted IR, PTEN upregulation, and AKT inactivation. Additionally, PA-induced hepatic IR caused a notable increase in STAU1, which was prevented by depleting GIGYF2. Notably, silencing STAU1 prevented GIGYF2-induced PTEN upregulation, PI3K/AKT pathway inactivation, and IR. STAU1 was found to stabilize PTEN mRNA by binding to its 3’UTR. In liver cells, tocopherol treatment inhibits GIGYF2 expression and mitigates PA-induced IR. In the in vivo mice model, GIGYF2 knockdown and tocopherol administration alleviate high-fat diet (HFD)-induced glucose intolerance and IR, along with the suppression of STAU1/PTEN and restoration of PI3K/AKT signaling.ConclusionsOur study discloses that GIGYF2 mediates obesity-related IR by disrupting the PI3K/AKT signaling axis through the up-regulation of STAU1/PTEN. Targeting GIGYF2 may offer a potential strategy for treating obesity-related metabolic diseases, including type 2 diabetes.Graphical

Liposomal quercetin: A promising strategy to combat hepatic insulin resistance and inflammation in type 2 diabetes mellitus

In type 2 diabetes mellitus, hepatic insulin resistance is intricately associated with oxidative stress and inflammation. Nonetheless, the lack of therapeutic interventions directly targeting hepatic dysfunction represents a notable gap in current treatment options. Flavonoids have been explored due to their potential antidiabetic effects. However, these compounds are associated with low bioavailability and high metabolization. In the present study, four flavonoids, kaempferol, quercetin, kaempferol-7-O-glucoside and quercetin-7-O-glucoside, were studied in a cellular model of hepatic insulin resistance using HepG2 cells. Quercetin was selected as the most promising flavonoid and incorporated into liposomes to enhance its therapeutic effect. Quercetin liposomes had a mean size of 0.12 µm, with an incorporation efficiency of 93 %. Quercetin liposomes exhibited increased efficacy in modulating insulin resistance. This was achieved through the modulation of Akt expression and the attenuation of inflammation, particularly via the NF-κB pathway, as well as the regulation of PGE2 and COX-2 expression. Furthermore, quercetin liposomes displayed a significant advantage over free quercetin in attenuating the production of reactive pro-oxidant species. These findings open new avenues for developing innovative therapeutic strategies to manage diabetes, emphasizing the potential of quercetin liposomes as a promising approach for targeting both hepatic insulin resistance and associated inflammation.

Diverse Strategies for Modulating Insulin Resistance: Causal or Consequential Inference on Metabolic Parameters in Treatment-Naïve Subjects with Type 2 Diabetes.

Bacground and Objectives: The objective of this study is to investigate how different therapies modulating insulin resistance, either causally or consequently, affect metabolic parameters in treatment-naïve subjects with T2DM. Subjects and Methods: A total of 212 subjects were assigned to receive either a tight Japanese diet (n = 65), pioglitazone at doses ranging from 15-30 mg/day (n = 70), or canagliflozin at doses ranging from 50-100 mg/day (n = 77) for a duration of three months. Correlations and changes (Δ) in metabolic parameters relative to insulin resistance were investigated. Results: Across these distinct therapeutic interventions, ΔHOMA-R exhibited significant correlations with ΔFBG and ΔHOMA-B, while demonstrating a negative correlation with baseline HOMA-R. However, other parameters such as ΔHbA1c, ΔBMI, ΔTC, ΔTG, Δnon-HDL-C, or ΔUA displayed varying patterns depending on the treatment regimens. Participants were stratified into two groups based on the median value of ΔHOMA-R: the lower half (X) and upper half (Y). Group X consistently demonstrated more pronounced reductions in FBG compared to Group Y across all treatments, while other parameters including HbA1c, HOMA-B, TC, TG, HDL-C, non-HDL-C, TG/HDL-C ratio, or UA exhibited distinct regulatory responses depending on the treatment administered. Conclusions: These findings suggest that (1) regression to the mean is observed in the changes in insulin resistance across these therapies and (2) the modulation of insulin resistance with these therapies, either causally or consequentially, results in differential effects on glycemic parameters, beta-cell function, specific lipids, body weight, or UA.

Beneficial Effects of Echinacoside on Cognitive Impairment and Diabetes in Type 2 Diabetic db/db Mice.

Cognitive dysfunction is an important comorbidity of diabetes. Insulin resistance may play a critical role in diabetes-related cognitive impairment. Echinacoside (ECH), a natural phenylethanoid glycoside, is the active component of anti-diabetes prescriptions in traditional Chinese medicine. Its effect on modulating insulin resistance has been confirmed but modulating neurodegenerative disease remains unclear. Db/db mice, a spontaneous type 2 diabetes mode, were intragastrically administered ECH by 300 mg/kg or an equivalent volume of saline. Weight, blood glucose, and insulin resistance index were measured. Morris water maze test was performed to observe the compound effects on cognition. Hippocampal lesions were observed by histochemical analysis. In db/db mice, ECH alleviated diabetes symptoms, memory loss, and hippocampal neuronal damage. Next, the expression of CD44 and phosphorylated tau was upregulated in diabetic mice. In addition, the insulin receptor substrate-1/phosphatidylinositol 3-kinase /protein kinase B signaling pathway was dysregulated in diabetic mice. All these dysregulations could be reversed by ECH. This study provides theoretical support and experimental evidence for the future application of ECH in diabetic cognition dysfunction treatment, promoting the development of traditional medicines.

Deletion of Irisin Mitigates HDAC4 Inhibitor-Elicited Protective Effect in Hemorrhage

Introduction: Histone deacetylate inhibition contributes critically to modulating insulin resistance and cardiovascular function. It remains unknown whether inhibition of specific HDAC isoform 4 could improve cardiac function and attenuates inflammatory response and whether HDAC4 inhibition-induced protection is related to irisin. The objective of this study is to investigate whether HDAC4 inhibition induced protective effect against hemorrhage-induced detrimental effects would be diminished by deletion of irisin. Method: Irisin knockout (irisin−/−) mice was generated by using the CRISPR/Cas-9 genome-editing system. Hemorrhage was induced in mice by achieving a mean arterial blood pressure of 35-45 mmHg for one hour, followed by two hours of resuscitation. Experimental groups were divided as followings: I) Wild type (WT)+Hemorrhage (control) (N=7): WT mice were subjected to hemorrhage for 60 minutes followed by resuscitation; II) NVS-HD-1+Hemorrhage (n=7): The same as the group I except that NVS-HD1, a selective HDAC inhibitor (3mg/kg) was infused during resuscitation; III) Irisin −/− +Hemorrhage (n=6): Irisin −/− mice underwent hemorrhage and resuscitation; IV) NVS-HD-1 + Irisin−/−+Hemorrhage (n=6): The same as the groups III except that NVS-HD-1 was given to Irisin −/− during resuscitation. Myocardial function and hemodynamics were assessed using echocardiography and femoral artery catheterization, respectively. Cytokine releases from serum were measured using Enzyme-linked immunosorbent assay (ELISA). Histological assessment was performed to determine tissue damage in both myocardium and skeletal muscles. TUNEL was carried out to assess apoptotic signal in tissues. Results: As compared to control group, HDAC4 inhibitor significantly improved the cardiac function and recovery of hemodynamics, which was associated with the decreased release of IL6 and TNF-α in hemorrhage. The infiltration of inflammatory cells and TUNEL positive apoptosis in muscles were mitigated by inhibition of HDAC4. However, HDAC4 inhibitor-induced myocardial protection and suppression of inflammation against hemorrhage was lost by genetic deletion of irisin. Conclusion: Selective inhibition of HDAC4 produced protective effects with an improvement in myocardial function and attenuation of inflammation against hemorrhage, which is dependent on irisin. The work is supported by the National Institute of General Medical Sciences (R01GM 141339), United States; the National Heart, Lung, and Blood Institute Grants (R01 HL089405), United States. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

TRIB2-Mediated Modulation of AMPK Promotes Hepatic Insulin Resistance.

Insulin resistance and its linked health complications are increasing in prevalence. Recent work has caused the role of Tribbles2 (TRIB2) in metabolism and cellular signaling to be increasingly appreciated, but its role in the progression of insulin resistance has not been elucidated. Here, we explore the functions of TRIB2 in modulating insulin resistance and the mechanism involved in insulin resistance mice and palmitic acid (PA) treated HepG2 cells. We demonstrate that whole-body knockout and hepatic-specific TRIB2 deficiency protect against diet-induced insulin resistance, inflammation and ER stress. Accordingly, upregulation of TRIB2 in the liver aggravates these metabolic disturbances in HFD-induced mice and ob/ob mice. Mechanistically, TRIB2 directly binds to the αγ-SBS domain of PRKAB through its pseudokinase domain, subsequently inhibiting the formation and activity of the AMPK complex. Moreover, the results of intervention against AMPK suggest that the effects of TRIB2 depend on AMPK. Our findings reveal that TRIB2 is a novel target for the treatment of insulin resistance and its associated metabolic complications and clarify the function of TRIB2 as a regulatory component of AMPK activity.

Melanoxetin: A Hydroxylated Flavonoid Attenuates Oxidative Stress and Modulates Insulin Resistance and Glycation Pathways in an Animal Model of Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus (DM) continues to escalate, necessitating innovative therapeutic approaches that target distinct pathways and address DM complications. Flavonoids have been shown to possess several pharmacological activities that are important for DM. This study aimed to evaluate the in vivo effects of the flavonoid melanoxetin using Goto-Kakizaki rats. Over a period of 14 days, melanoxetin was administered subcutaneously to investigate its antioxidant, anti-inflammatory, and antidiabetic properties. The results show that melanoxetin reduced insulin resistance in adipose tissue by targeting protein tyrosine phosphatase 1B. Additionally, melanoxetin counteracted oxidative stress by reducing nitrotyrosine levels and modulating superoxide dismutase 1 and hemeoxygenase in adipose tissue and decreasing methylglyoxal-derived hydroimidazolone (MG-H1), a key advanced glycation end product (AGE) implicated in DM-related complications. Moreover, the glyoxalase 1 expression decreased in both the liver and the heart, correlating with reduced AGE levels, particularly MG-H1 in the heart. Melanoxetin also demonstrated anti-inflammatory effects by reducing serum prostaglandin E2 levels, and increasing the antioxidant status of the aorta wall through enhanced acetylcholine-dependent relaxation in the presence of ascorbic acid. These findings provide valuable insights into melanoxetin's therapeutic potential in targeting multiple pathways involved in type 2 DM, particularly in mitigating oxidative stress and glycation.

Physical Activity, Insulin Resistance and Cancer: A Systematic Review

Introduction: Insulin resistance (IR), a key aspect of type 2 diabetes and a defining characteristic of obesity and its associated conditions, emerges as a mechanistic pathway potentially implicated in cancer pathophysiology. This presents an appealing intervention target for cancer patients. The objective of this study is to conduct a systematic review, examining the scientific evidence regarding the impact of physical activity on modifying insulin resistance in individuals with cancer. Methods: The selection criteria were specific: only randomized controlled clinical trials published in the last 13 years and written in English or Spanish were included. The databases utilized for the search included PubMed, Scopus, Cochrane Library, EBSCO, and WEB OF SCIENCE. The protocol for this review was duly registered in the International Register of Systematic Reviews (CRD42023435002). The final search was conducted on 14 May 2023. Results: The outcomes were assessed using the tool proposed by the Cochrane Handbook to evaluate the risk of bias in the included studies. Among the 12 studies incorporated, 8 demonstrated a low risk of bias, two had an unclear risk of bias, and the remaining two showed a high risk of bias. The variety of exercise types used across all studies was extensive, making definitive conclusions challenging. Physical activity was linked to enhanced insulin sensitivity in seven studies, while five studies showed no significant changes in insulin resistance between the intervention and control groups. Importantly, none of the interventions employed in the included studies exhibited adverse effects on the study participants. Conclusions: The role of exercise as a medicine against insulin resistance has been evidenced in many different studies, mostly related to obesity and cardiovascular diseases. Engaging in physical activity could be a healthy option to combat the effects of insulin resistance in cancer patients, although evidence is weak and limited, according to the results of our systemic review. We further found that literature is lacking at the level of optimal doses, timing, and type of exercise. More studies are needed with more defined PA programs in type and length.

Examining the molecular mechanisms of topiramate in alleviating insulin resistance: A study on C2C12 myocytes and 3T3L-1 adipocytes.

Migraine, a severely debilitating condition, may be effectively managed with topiramate, known for its migraine prevention and weight loss properties due to changes in body muscle and fat composition and improved insulin sensitivity. However, the mechanism of topiramate in modulating insulin response in adipocytes and myocytes remains elusive. This study aims to elucidate these molecular mechanisms, offering insights into its role in weight management for migraine sufferers and underpinning its clinical application. Insulin resistance improvements were evaluated through glucose uptake measurements in C2C12 muscle cells and 3T3L-1 adipocytes, with Oil red O staining conducted on adipocytes. RNA-seq transcriptome analysis was used to identify the regulatory target genes of topiramate in these cells. The involvement of key genes and pathways was further validated through western blot analysis. Topiramate effectively reduced insulin resistance in C2C12 and 3T3L-1 cells. In C2C12 cells, it significantly lowered SORBS1 gene and protein levels. In 3T3L-1 cells, topiramate upregulated CTGF and downregulated MAPK8 and KPNA1 genes. Changes were notable in nuclear cytoplasmic transport and circadian signaling pathways. Furthermore, it caused downregulation of MKK7, pJNK1/ JNK1, BMAL1, and CLOCK proteins compared to the insulin-resistant model. This study provides preliminary insights into the mechanisms through which topiramate modulates insulin resistance in C2C12 myocytes and 3T3L-1 adipocytes, enhancing our understanding of its therapeutic potential in managing weight and insulin sensitivity in migraine patients.

Inulin-type fructans with different degrees of polymerization improve insulin resistance, metabolic parameters, and hormonal status in overweight and obese women with polycystic ovary syndrome: A randomized double-blind, placebo-controlled clinical trial.

Polycystic ovary syndrome (PCOS) is associated with reproductive disorders and adverse cardiometabolic risk factors that can negatively impact the general health of women. Inulin-type fructans (ITFs) are proposed to beneficially affect risk factors associated with metabolic disorders. Whether ITFs can help with the management of PCOS by modifying insulin resistance (IR) and androgen levels has not yet been explored. The aim of this study was to investigate the effects of ITFs with different degrees of polymerization on insulin resistance, blood lipids, anthropometric measures, and hormonal status in overweight and obese women with PCOS. In a randomized double-blind placebo-controlled trial, seventy-five women with PCOS aged 18-40 years old were randomly assigned to receive 10 g/day of high-performance inulin (HPI) or oligofructose-enriched inulin (OEI) or maltodextrin for 12 weeks. Biochemical and clinical outcomes were measured at baseline and after the intervention. Participants in the HPI and OEI groups experienced improvements in waist circumference, total testosterone, free androgen index, sex hormone-binding globulin, and triglycerides compared to the placebo group. Also, the number of women with irregular menses or oligomenorrhoea decreased significantly in both ITF groups. Participants in the HPI group reported lower body mass, fasting insulin, and HOMA-IR, as well as a higher quantitative insulin sensitivity check index. ITF supplementation, especially with long-chain ITFs, when given for 12 weeks may improve metabolic outcomes, androgen status and clinical manifestations in women with PCOS.

Network pharmacology-based elucidation of bioactive compounds and experimental exploration of antidiabetic mechanisms of Hydrolea zeylanica

This investigation systematically explored the underlying antidiabetic mechanism of Hydrolea zeylanica (HZH) by the approach of network pharmacology and experimental validation in restoring glucose homeostasis, and inflammation in high fat diet fed-streptozotocin (HFD/STZ)-induced type II diabetes (T2DM) rats. Network pharmacology analysis was conducted on 32 bioactive components of HZH. In silico ADME prediction, and physicochemical analysis of 32 compounds were used to assess their drug-likeness. Common targets between selected compounds, and T2DM were subjected for GO enrichment. Compound-target-pathway network was predicted with selected compounds and targets. HZH (300 and 400 mg/kg) were considered for GLUTs expression, and inflammation cytokines in T2DM rats. Network pharmacology showed the core relationship between 13 selected compounds, and 194 key target genes in insulin resistance, type II diabetes mellitus, insulin signaling pathways in T2DM. AKT1, AKT2, GSK3B, IL6, INSR, MAPK8, PPARA, GLUT1, GLUT2, GLUT4 were observed as the key targets in PPI network. HZH-400 significantly restored glucose homeostasis, and inflammatory markers in T2DM rats. It altered GLUT2, GLUT4 expression in liver, and skeletal muscle to normal. Bioactive compounds of HZH were found to control blood sugar level by modulating insulin resistance, type II diabetes mellitus, insulin signaling pathways, and glucose homeostasis, which in turn improved glucose uptake, insulin production in diabetes as shown in network pharmacology and glucose transporter expression studies.

Periostin acts as a bridge between gestational diabetes mellitus (GDM) and chronic inflammation to modulate insulin resistance by modulating PPARα/NF-κB/TNF-α signaling pathway.

Gestational diabetes mellitus (GDM) is considered an imbalance of glucose metabolism and insulin resistance during pregnancy. To evaluate the levels of periostin (POSTN) in patients with GDM and investigate the association between POSTN and GDM. A total of 30 pregnant women (NC group) and 30 pregnant women with GDM (GDM group) were involved. The GDM mouse model was established by intraperitoneally injecting streptozotocin. The oral glucose tolerance test (OGTT), insulin, and insulin resistance indices were tested. An immunohistochemical and Western blot assay was conducted to determine the expression of POSTN, PPARα, TNF-α, and NF-kB. HE staining was performed to evaluate inflammation in the placental tissues of women with GDM and GDM mice. POSTN-siRNA was transfected into glucose-pretreated HTR8 cells, and pAdEasy-m-POSTN shRNA was infected in GDM mice. The RT-PCR assay determined the gene transcription of POSTN, TNF-α, NF-kB, and PPARα. Pregnant women in the GDM group demonstrated significantly higher OGTT (p<0.05), insulin levels (p<0.05) and insulin resistance (p<0.05) compared to those of the NC group. The serum levels of POSTN in pregnant women of the GDM group were significantly higher than that of the NC group (p<0.05). The obvious inflammation was activated in pregnant women in the GDM group. POSTN-siRNA significantly enhanced the cell viability of glucose-treated HTR8 cells compared to that without glucose treatment (p<0.05). POSTN-siRNA (pAdEasy-m-POSTN shRNA) markedly reduced the glucose level of glucose-treated HTR8 cells (GDM mice) compared to that without treatment (p<0.05). POSTN-siRNA (pAdEasy-m-POSTN shRNA) promoted PPARα gene transcription (p<0.05) and inhibited NF-kB/TNF-α gene transcription (p<0.05) in glucose-treated HTR8 cells (GDM mice) compared to those without treatment. POSTN-siRNA modulated NF-kB/TNF-α pathway mediated inflammation by regulating PPARα in HTR8 cells and GDM mice. PPARα participated in POSTN-associated inflammation. pAdEasy-m-POSTN shRNA inhibited T-CHO/TG levels in GDM mice compared to those without treatment (p<0.05). All the effects of POSTN-siRNA (pAdEasy-m-POSTN shRNA) were obviously blocked by PPARα inhibitor treatment. POSTN levels were significantly higher in pregnant women with GDM and were associated with chronic inflammation and PPARα expression. POSTN may act as a bridge between GDM and chronic inflammation to modulate insulin resistance by modulating PPARα/NF-κB/TNF-α signaling pathway.

Woman’s microbiome and obstetrical and perinatal risks: what do they have in common?

The article is devoted to the review of modern scientific publications about the microbiome of a woman and its importance in obstetric and perinatal practice. The composition of the microbiome is changed both in the process of human evolution and personally and in different periods of a person’s life. However, on the other hand, the microbiome is influenced by the specific environment in which a person lives. It consists of a certain collection of genomes of all microorganisms. Complications during pregnancy occur frequently, according to statistics – in every sixth pregnant woman, and pose a danger to the health of the mother and child.During pregnancy, the richness and diversity of the vaginal microbiome decreases, and different species of Lactobacillus play a dominant role. The microbiome stability is hypothesized to be associated with higher levels of estrogen concentration, absence of menstruation, and modification of cervical and vaginal fluids. During an uncomplicated pregnancy, the taxonomic composition of the vaginal microbiota remains stable with the exception of the period before labor, when there is an increase in microbial diversity. This makes the vaginal microbiome similar to that of a non-pregnant woman and is believed to be a trigger for the labor process to begin.The recent studies have determined a relationship between changes in the microbiome during pregnancy and the occurrence of complications in these women. Any change or disturbance in the microbiome balance can be involved in inflammatory processes, which can potentially have adverse effects on the course of pregnancy. A major interaction between the oral microbiome and preeclampsia involves the production of nitrogen derivatives, especially nitric oxide (NO). NO is produced from L-arginine via NO synthases (NOS), and is involved in vascular processes, especially vasodilation and tissue protection. Also, NO is indirectly involved in the processes that occur in the presence of chronic cardiovascular diseases, including hypertension and preeclampsia.In recent years, scientists have begun actively to study a correlation between changes in the gut microbiome and various nosologies regarding gestational diabetes. There is not much of this data at the moment. The gut microbiome is known to modulate insulin resistance and the inflammatory response, and changes in the microbiome may be associated with metabolic diseases. It is hypothesized that changes in the gut microbiome may lead to metabolic diseases through several mechanisms: abnormal intestinal permeability, increased absorption of lipopolysaccharide, abnormal production of short-chain fatty acids, altered conversion of primary bile acids, and enhanced production of bacterial toxins (e.g., trimethylamine-N-oxide).During full-term pregnancy, the “dynamic stability” of the vaginal microbiome is described as a higher concentration of Lactobacillus species starting at 20 weeks of gestation due to increased glycogen availability and a less complex and diverse microflora. This condition may be due to the lack of cyclical hormonal changes during pregnancy. Lactobacillus and small bacterial diversity are thought to be critical factors for the initiation of labor at the end of the pregnancy.Future therapeutic strategies are likely to be applied to modulate the composition of the microbiome, including the use of pro- and prebiotics and dietary modification. However, further research is needed to identify specific tools that can be used to develop personalized therapeutic approaches for individualized prevention and treatment.

Irisin deficiency exacerbates diet-induced insulin resistance and cardiac dysfunction in type II diabetes in mice.

Irisin is involved in the regulation of a variety of physiological conditions, metabolism, and survival. We and others have demonstrated that irisin contributes critically to modulation of insulin resistance and the improvement of cardiac function. However, whether the deletion of irisin will regulate cardiac function and insulin sensitivity in type II diabetes remains unclear. We utilized the CRISPR/Cas-9 genome-editing system to delete irisin globally in mice and high-fat diet (HFD)-induced type II diabetes model. We found that irisin deficiency did not result in developmental abnormality during the adult stage, which illustrates normal cardiac function and insulin sensitivity assessed by glucose tolerance test in the absence of stress. The ultrastructural analysis of the transmission electronic microscope (TEM) indicated that deletion of irisin did not change the morphology of mitochondria in myocardium. Gene expression profiling showed that several key signaling pathways related to integrin signaling, extracellular matrix, and insulin-like growth factors signaling were coordinately downregulated by deletion of irisin. However, when mice were fed a high-fat diet and chow food for 16 wk, ablation of irisin in mice exposed to HFD resulted in much more severe insulin resistance, metabolic derangements, profound cardiac dysfunction, and hypertrophic response and remodeling as compared with wild-type control mice. Taken together, our results indicate that the loss of irisin exacerbates insulin resistance, metabolic disorders, and cardiac dysfunction in response to HFD and promotes myocardial remodeling and hypertrophic response. This evidence reveals the molecular evidence and the critical role of irisin in modulating insulin resistance and cardiac function in type II diabetes.NEW & NOTEWORTHY By utilizing the CRISPR/Cas-9 genome-editing system and high-fat diet (HFD)-induced type II diabetes model, our results provide direct evidence showing that the loss of irisin exacerbates cardiac dysfunction and insulin resistance while promoting myocardial remodeling and a hypertrophic response in HFD-induced diabetes. This study provides new insight into understanding the molecular evidence and the critical role of irisin in modulating insulin resistance and cardiac function in type II diabetes.

Micronutrients in High-Fat Diet Modify Insulin Resistance and Its Regulatory Genes in Adult Male Mice.

Obesity and insulin resistance (IR) are associated with epigenetic changes of gene expression. However, the relationship between micronutrients, epigenetic regulation of gene expression, and IR during development of diet-induced obesity has yet to be defined. Our objective is to describe the effect of micronutrient addition to diets on IR and its related genes during obesity development. Male C57BL/6J mice are fed a high-fat (HFD) or low-fat (LFD) diets with or without a multi-vitamin mineral mix (MVM) addition containing vitamins A, B1, B6, B12, and Zn, and Se for 9 weeks. Compared to LFD mice, HFD mice have higher body weight, IR, fasting glucose, insulin, C-peptide, leptin, and hepatic triglyceride concentrations, and dysregulated gene expression in liver, muscle, pancreas, and fat tissues (p < 0.05). The addition of MVM reduces these HFD-induced effects. HFD downregulates 27 genes associated with insulin regulation and adipose tissue function across all tissues by an average of 47% and upregulates five genes by 230% (p < 0.001). Adding MVM downregulates five genes and upregulates one in HFD-fed mice. Both HFD and MVM alter one-carbon metabolites. Addition of micronutrients to the HFD decreases IR and modifies associated gene expression in obese and lean mice.

A Descriptive Review of the Action Mechanisms of Berberine, Quercetin and Silymarin on Insulin Resistance/Hyperinsulinemia and Cardiovascular Prevention.

Insulin resistance (IR) and the associated hyperinsulinemia are early pathophysiological changes which, if not well treated, can lead to type 2 diabetes, endothelial dysfunction and cardiovascular disease. While diabetes care is fairly well standardized, the prevention and treatment of IR lacks a single pharmaceutical approach and many lifestyle and dietary interventions have been proposed, including a wide range of food supplements. Among the most interesting and well-known natural remedies, alkaloid berberine and the flavonol quercetin have particular relevance in the literature, while silymarin-the active principle of the Silybum marianum thistle-was traditionally used for lipid metabolism disorders and to sustain liver function. This review describes the major defects of insulin signaling leading to IR and the main properties of the three mentioned natural substances, their molecular targets and synergistic action mechanisms. The actions of berberine, quercetin and silymarin are partially superimposable as remedies against reactive oxygen intermediates generated by a high-lipid diet and by NADPH oxidase, which is triggered by phagocyte activation. Furthermore, these compounds inhibit the secretion of a battery of pro-inflammatory cytokines, modulate intestinal microbiota and are especially able to control the various disorders of the insulin receptor and post-receptor signaling systems. Although most of the evidence on the effects of berberine, quercetin and silymarin in modulating insulin resistance and preventing cardiovascular disease derive from experimental studies on animals, the amount of pre-clinical knowledge strongly suggests the need to investigate the therapeutic potential of these substances in human pathology.

Baseline level and change trajectory of the triglyceride-glucose index in relation to the development of NAFLD: a large population-based cohort study.

Insulin resistance (IR) and nonalcoholic fatty liver disease (NAFLD) are closely related. The triglyceride-glucose index (TyG index) has been proposed as a new indicator of IR. It remains unclear whether the triglyceride-glucose (TyG) index is prospectively associated with incident nonalcoholic fatty liver disease (NAFLD). This large-scale study comprised 1 prospective cohort totaling 22,758 subjects without NAFLD at baseline who underwent repeated health examinations and 1 subcohort totaling 7,722 subjects with more than three visits. The TyG index was ascertained mathematically by ln (fasting triglycerides [mg/dL] × fasting glucose [mg/dL]/2). NAFLD was diagnosed by ultrasound without other concomitant liver diseases. A combinatorial Cox proportional hazard model and latent class growth mixture modeling method were used to identify the association of the TyG index and its transition trajectories with NAFLD risk. During 53,481 person-years of follow-up, there were 5319 incident cases with NAFLD. Compared with those in the lowest quartile of the baseline TyG index, participants in the highest quartile had 2.52-fold (95% confidence interval, 2.21-2.86) higher odds of incident NAFLD. Similarly, restricted cubic spline analysis showed a dose-response relationship (p nonlinearity<0.001). Subgroup analyses showed a more significant association in the female and normal body size populations (p for interaction<0.001). Three distinct trajectories of changes in the TyG index were identified. Compared with the continued low group, the moderately increasing and highly increasing groups conferred 1.91-fold (1.65-2.21) and 2.19-fold (1.73-2.77) higher NAFLD risk, respectively. Participants with a higher baseline TyG index or a higher excessive TyG exposure were associated with an increased NAFLD risk. The findings imply that lifestyle interventions and modulation of IR might be considered to both reduce TyG index levels and prevent NAFLD development.