Signaling defects associated with insulin resistance in nondiabetic and diabetic individuals and modification by sex.
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SUBMITTER: Haider N
PROVIDER: S-EPMC8553553 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundInsulin resistance (IR) evolved from excessive energy intake and poor energy expenditure, affecting the patient's quality of life. Amino acid and acylcarnitine metabolomic profiles have identified consistent patterns associated with metabolic disease and insulin sensitivity. Here, we have measured a wide array of metabolites (30 acylcarnitines and 20 amino acids) with the MS/MS and investigated the association of metabolic profile with insulin resistance.MethodsThe study population (n = 403) was randomly chosen from non-diabetic participants of the Surveillance of Risk Factors of NCDs in Iran Study (STEPS 2016). STEPS 2016 is a population-based cross-sectional study conducted periodically on adults aged 18-75 years in 30 provinces of Iran. Participants were divided into two groups according to the optimal cut-off point determined by the Youden index of HOMA-IR for the diagnosis of metabolic syndrome. Associations were investigated using regression models adjusted for age, sex, and body mass index (BMI).ResultsPeople with high IR were significantly younger, and had higher education level, BMI, waist circumference, FPG, HbA1c, ALT, triglyceride, cholesterol, non-HDL cholesterol, uric acid, and a lower HDL-C level. We observed a strong positive association of serum BCAA (valine and leucine), AAA (tyrosine, tryptophan, and phenylalanine), alanine, and C0 (free carnitine) with IR (HOMA-IR); while C18:1 (oleoyl L-carnitine) was inversely correlated with IR.ConclusionsIn the present study, we identified specific metabolites linked to HOMA-IR that improved IR prediction. In summary, our study adds more evidence that a particular metabolomic profile perturbation is associated with metabolic disease and reemphasizes the significance of understanding the biochemistry and physiology which lead to these associations.
| S-EPMC9404631 | biostudies-literature
Project description:This study examined associations of thyroid hormone levels and insulin resistance (IR) in non-diabetic individuals. Using a cross-sectional design, 2007-2008 data from the National Health and Nutrition Examination Survey (NHANES) were analyzed. NHANES participants ≥20 years of age with complete data of interest were included. The homeostatic model assessment (HOMA) was used to quantify IR, and treated as a continuous variable. Self-reported diabetes or a fasting glucose ≥7 mmol/L were used as criteria to exclude diabetic subjects. Race, liver function, obesity, hypertension, dyslipidemia, smoking, physical activity, vigorous recreational activity, 2-hour glucose, hemoglobin A1C (HbA1C), high-density lipoprotein, triglyceride, vitamin D and C-reactive protein were covariates significantly associated with HOMA-IR. A total of 1,560 non-diabetic subjects were included in the analysis. When adjusted for all factors significant in the univariate analysis (race, liver function, obesity, hypertension, dyslipidemia, smoking, physical activity, vigorous recreational activity, 2-hour glucose, HbA1C, high-density lipoprotein, triglyceride, vitamin D, and CRP) low total triiodothyronine (TT3) and low free T3 (FT3) were significantly associated with decreased HOMA-IR (adjusted coefficient = -0.486, 95% confidence interval [CI]: -0.936, -0.036; adjusted coefficient = -1.151, 95% CI: -1.952, -0.350, respectively). Insulin resistance is associated with low thyroid hormone levels in non-diabetic individuals.
| S-EPMC6048097 | biostudies-literature
Project description:Type 2 diabetes is characterized by poor glucose uptake in metabolic tissues and manifests when insulin secretion fails to cope with worsening insulin resistance. In addition to its effects on skeletal muscle, liver, and adipose tissue metabolism, it is evident that insulin resistance also affects pancreatic β-cells. To directly examine the alterations that occur in islet morphology as part of an adaptive mechanism to insulin resistance, we evaluated pancreas samples obtained during pancreatoduodenectomy from nondiabetic subjects who were insulin-resistant or insulin-sensitive. We also compared insulin sensitivity, insulin secretion, and incretin levels between the two groups. We report an increased islet size and an elevated number of β- and α-cells that resulted in an altered β-cell-to-α-cell area in the insulin- resistant group. Our data in this series of studies suggest that neogenesis from duct cells and transdifferentiation of α-cells are potential contributors to the β-cell compensatory response to insulin resistance in the absence of overt diabetes.
| S-EPMC3931397 | biostudies-literature
Project description:The prevalence of insulin resistance (IR) is increasing worldwide because of increasing age, obesity, and physical inactivity. Emerging evidence supports a direct proatherogenic effect of IR on the coronary vasculature, but the relation between IR and angiographic atherosclerosis in a real-world clinical setting is uncertain. In this work, we assessed whether IR is independently associated with clinically significant angiographic atherosclerosis in nondiabetic individuals.We examined the association between IR and the extent of coronary atherosclerosis determined by angiography in 1073 nondiabetic patients surviving acute myocardial infarction. Patients were divided into quartiles on the basis of the homeostasis model assessment grading of IR, and associations between IR and multivessel coronary artery disease, defined as ? 2 arteries with ? 70% stenosis (or ? 50% left main stenosis), were analyzed in bivariate and multivariable modeling. Overall, the cohort had a median age of 56 years; 28.9% women and 21.8% nonwhite. The crude prevalence of multivessel coronary artery disease was 37.8%, 42.3%, 47.2%, and 48.0% for homeostasis model assessment grading of IR quartiles 1, 2, 3, and 4, respectively (P(trend) = 0.009). In multivariable modeling, compared with quartile 1, both quartile 3 (relative risk [95% confidence interval], 1.31 [1.07-1.60]) and quartile 4 (1.29 [1.03-1.60]) were independently associated with multivessel coronary artery disease. Covariates in the model included patient demographic and clinical characteristics and metabolic factors (low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, triglyceride, glycosylated hemoglobin, and high-sensitivity C-reactive protein).We demonstrate an independent association between IR and multivessel coronary artery disease in nondiabetic postmyocardial infarction patients. Our findings strengthen the experimental evidence for a direct atherogenic effect of IR independent of glucose control and other components of the metabolic syndrome.
| S-EPMC3855677 | biostudies-literature
Project description:OBJECTIVE:Human adenovirus type 36 (Ad-36) increases adiposity but improves insulin sensitivity in experimentally infected animals. We determined the ability of Ad-36 to increase glucose uptake by human primary skeletal muscle (HSKM) cells. RESEARCH DESIGN AND METHODS:The effect of Ad-36 on glucose uptake and cell signaling was determined in HSKM cells obtained from type 2 diabetic and healthy lean subjects. Ad-2, another human adenovirus, was used as a negative control. Gene expression and proteins of GLUT1 and GLUT4 were measured by real-time PCR and Western blotting. Role of insulin and Ras signaling pathways was determined in Ad-36-infected HSKM cells. RESULTS:Ad-36 and Ad-2 infections were confirmed by the presence of respective viral mRNA and protein expressions. In a dose-dependent manner, Ad-36 significantly increased glucose uptake in diabetic and nondiabetic HSKM cells. Ad-36 increased gene expression and protein abundance of GLUT1 and GLUT4, GLUT4 translocation to plasma membrane, and phosphatidylinositol 3-kinase (PI 3-kinase) activity in an insulin-independent manner. In fact, Ad-36 decreased insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation and IRS-1-and IRS-2-associated PI 3-kinase activities. On the other hand, Ad-36 increased Ras gene expression and protein abundance, and Ras siRNA abrogated Ad-36-induced PI 3-kinase activation, GLUT4 protein abundance, and glucose uptake. These effects were not observed with Ad-2 infection. CONCLUSIONS:Ad-36 infection increases glucose uptake in HSKM cells via Ras-activated PI 3-kinase pathway in an insulin-independent manner. These findings may provide impetus to exploit the role of Ad-36 proteins as novel therapeutic targets for improving glucose handling.
| S-EPMC2453622 | biostudies-literature
Project description:Insulin resistance (IR) and the consequences of compensatory hyperinsulinemia are pathogenic factors for a set of metabolic abnormalities, which contribute to the development of diabetes mellitus and cardiovascular diseases. We compared traditional lipid levels and ratios and combined them with fasting plasma glucose (FPG) levels or adiposity status for determining their efficiency as independent risk factors for IR.We enrolled 511 Taiwanese individuals for the analysis. The clinical usefulness of various parameters--such as traditional lipid levels and ratios; visceral adiposity indicators, visceral adiposity index (VAI), and lipid accumulation product (LAP); the product of triglyceride (TG) and FPG (the TyG index); TyG with adiposity status (TyG-body mass index [BMI]) and TyG-waist circumference index [WC]); and adipokine levels and ratios--was analyzed to identify IR.For all lipid ratios, the TG/high-density lipoprotein cholesterol (HDL-C) ratio had the highest additional percentage of variation in the homeostasis model assessment of insulin resistance (HOMA-IR; 7.0% in total); for all variables of interest, TyG-BMI and leptin-adiponectin ratio (LAR) were strongly associated with HOMA-IR, with 16.6% and 23.2% of variability, respectively. A logistic regression analysis revealed similar patterns. A receiver operating characteristic (ROC) curve analysis indicated that TG/HDL-C was a more efficient IR discriminator than other lipid variables or ratios. The area under the ROC curve (AUC) for VAI (0.734) and TyG (0.708) was larger than that for TG/HDL-C (0.707). TyG-BMI and LAR had the largest AUC (0.801 and 0.801, respectively).TyG-BMI is a simple, powerful, and clinically useful surrogate marker for early identification of IR.
| S-EPMC4773118 | biostudies-other
Project description:ObjectiveIt is unclear whether monocyte/macrophage insulin signaling in humans is affected by type 2 diabetes (T2DM), systemic insulin sensitivity, and other unknown factors.Research design and methodsFifty-three adult volunteers (control group) not taking any medication and without cardiovascular risk factors, and 59 patients with T2DM (T2DM group) were included. Monocytes were isolated and cultured from all participants.ResultsIn cultured monocytes, insulin-stimulated AKT and FOXO3 phosphorylation was significantly suppressed in T2DM compared with that in the control group. Insulin-stimulated phosphorylation of AKT was significantly correlated with body mass index and serum insulin level only in the control group. In both groups, significant negative correlation between age and insulin-stimulated phosphorylation of AKT and FOXO3 was commonly observed. In the control group, lipopolysaccharide (LPS)-stimulated induction of TNFA, and NOS2 was significantly and negatively correlated with insulin-stimulated AKT phosphorylation. Age was also significantly correlated with LPS-stimulated induction of TNFA.DiscussionAging plays an important role in the development of monocyte insulin resistance, not only in patients with T2DM but also in healthy participants. Monocyte insulin sensitivity is negatively correlated with inflammatory responses and may be helpful for subclinical risk assessment of CVDs and/or insulin resistance in participants without risk factors.
| S-EPMC8481716 | biostudies-literature
Project description:A hyperglycemic and hyperinsulinemic environment characteristic of type 2 diabetes causes insulin resistance. In adipocytes, defects in both insulin sensitivity and maximum response of glucose transport have been demonstrated. To investigate the molecular mechanisms, freshly isolated rat adipocytes were incubated in control (5.6 mM glucose, no insulin) and high glucose (20 mM)/high insulin (100 nM) (HG/HI) for 18 hours to induce insulin resistance. Insulin-resistant adipocytes manifested decreased sensitivity of glucose uptake associated with defects in insulin receptor substrate (IRS)-1 Tyr phosphorylation, association of p85 subunit of phosphatidylinositol-3-kinase, Akt Ser473 and Thr308 phosphorylation, accompanied by impaired glucose transporter 4 translocation. In contrast, protein kinase C (PKC)-? activity was augmented by chronic HG/HI. Inhibition of PKC-? with a specific cell-permeable peptide reversed the signaling defects and insulin sensitivity of glucose uptake. Transfection of dominant-negative, kinase-inactive PKC-? blocked insulin resistance, whereas constitutively active PKC-? recapitulated the defects. The HG/HI incubation was associated with stimulation of IRS-1 Ser318 and Akt Thr34 phosphorylation, targets of PKC-?. Transfection of IRS-1 S318A and Akt T34A each partially corrected insulin signaling, whereas combined transfection of both completely normalized insulin signaling. In vivo hyperglycemia/hyperinsulinemia in rats for 48 hours similarly resulted in activation of PKC-? and increased phosphorylation of IRS-1 Ser318 and Akt Thr34. These data indicate that impairment of insulin signaling by chronic HG/HI is mediated by dual defects at IRS-1 and Akt mediated by PKC-?.
| S-EPMC5939637 | biostudies-literature
Project description:BackgroundLipoprotein insulin resistance (LPIR) score is a composite biomarker representative of atherogenic dyslipidemia characteristic of early insulin resistance. It is elevated in obesity and may provide information not captured in glycosylated hemoglobin and homeostatic model assessment for insulin resistance. While bariatric surgery reduces diabetes incidence and resolves metabolic syndrome, the effect of bariatric surgery on LPIR is untested.ObjectivesWe sought to assess the effects of Roux-en-Y gastric bypass and sleeve gastrectomy on LPIR in nondiabetic women with obesity.SettingNonsmoking, nondiabetic, premenopausal Hispanic women, age ≥18 years, undergoing Roux-en-Y gastric bypass or sleeve gastrectomy at Bellevue Hospital were recruited for a prospective observational study.MethodsAnthropometric measures and blood sampling were performed preoperatively and at 6 and 12 months postoperatively. LPIR was measured by nuclear magnetic resonance spectroscopy.ResultsAmong 53 women (Roux-en-Y gastric bypass, n = 22; sleeve gastrectomy, n = 31), mean age was 32 ± 7 years and body mass index 44.1 ± 6.4 kg/m2. LPIR was reduced by 35 ± 4% and 46 ± 4% at 6 and 12 months after surgery, respectively, with no difference by procedure. Twenty-seven of 53 patients met International Diabetes Federation criteria for metabolic syndrome preoperatively and had concomitant higher homeostatic model assessment for insulin resistance, glycosylated hemoglobin, nonhigh-density lipoprotein-cholesterol and LPIR. Twenty-five of 27 patients experienced resolution of metabolic syndrome postoperatively. Concordantly, the preoperative differences in homeostatic model assessment for insulin resistance, glycosylated hemoglobin, and nonhigh-density lipoprotein-cholesterol between those with and without metabolic syndrome resolved at 6 and 12 months. In contrast, patients with metabolic syndrome preoperatively exhibited greater LPIR scores at 6 and 12 months postoperatively.ConclusionThis is the first study to demonstrate improvement in insulin resistance, as measured by LPIR, after bariatric surgery with no difference by procedure. This measure, but not traditional markers, was persistently higher in patients with a preoperative metabolic syndrome diagnosis, despite resolution of the condition.
| S-EPMC7541552 | biostudies-literature
Project description:Aims/hypothesisObesity is the dominant cause of insulin resistance. In adult humans it is characterised by a combination of adipocyte hypertrophy and, to a lesser extent, adipocyte hyperplasia. As hypertrophic adipocytes secrete more leptin and less adiponectin, the plasma leptin:adiponectin ratio (LAR) has been proposed as a potentially useful measure of insulin resistance and vascular risk. We sought to assess the usefulness of the LAR as a measure of insulin resistance in non-diabetic white adults.MethodsLeptin and adiponectin levels were measured in 2,097 non-diabetic individuals from the Ely and European Group for the Study of Insulin Resistance (EGIR) Relationship between Insulin Sensitivity and Cardiovascular Risk (RISC) study cohorts. LAR was compared with fasting insulin and HOMA-derived insulin sensitivity (HOMA-S) in all individuals and with the insulin sensitivity index (M/I) from hyperinsulinaemic-euglycaemic clamp studies in 1,226 EGIR RISC participants.ResultsThe LAR was highly correlated with HOMA-S in men (r = -0.58, p = 4.5 x 10(-33) and r = -0.65, p = 1.1 x 10(-66) within the Ely and EGIR RISC study cohorts, respectively) and in women (r = -0.51, p = 2.8 x 10(-36) and r = -0.61, p = 2.5 x 10(-73)). The LAR was also strongly correlated with the clamp M/I value (r = -0.52, p = 4.5 x 10(-38) and r = -0.47, p = 6.6 x 10(-40) in men and women, respectively), similar to correlations between HOMA-S and the M/I value.Conclusions/interpretationThe leptin:adiponectin ratio is a useful measure of insulin resistance in non-diabetic white adults. These data highlight the central role of adipocyte dysfunction in the pathogenesis of insulin resistance. Given that variations between fasting and postprandial leptin and adiponectin levels tend to be small, the leptin to adiponectin ratio might also have potential value in assessing insulin sensitivity in the non-fasted state.
| S-EPMC2759015 | biostudies-literature