Link between Insulin Resistance and Obesity—From Diagnosis to Treatment

Epicardial fat and insulin resistance in healthy older adults: a cross-sectional analysis

Insulin resistance (IR) and cardiovascular diseases (CVD) are relevant concerns in the elderly population; as the world's population ages, IR and CVD are two universal public health problems. While a link between IR a CVD has been established, the mediating mechanisms are uncertain and rigorous investigations are needed to fully elucidate them. The study aimed at assessing the relationship between epicardial fat (EF), an indicator of cardiovascular risk, and IR in Italian free-living elderly (n = 89). Baseline data from a previous cohort was used. Anthropometric measurements, EF, and IR-related variables, including the HOMA-IR index and other biochemical parameters were obtained. The correlation between EF and IR was explored. Further analysis was conducted to identify significant differences regarding IR variables among EF quartiles. EF correlated positively with glucose levels in females, males and the total population. The pairwise comparison among EF quartiles showed significant differences in glucose levels, HOMA-IR index, triglycerides, and total cholesterol levels. To our knowledge, this is the only study assessing the relationship between EF and IR in healthy elderly, while most of the studies have investigated EF and IR in diseased populations. Further research with a longitudinal approach should be conducted to design concrete conclusions about this relationship.

Weight Gain from Birth to Adolescence and TyG Index at Age 18 Years: A Cohort Study in Northeast Brazil

BACKGROUND

Developmental models suggest that the phenotypes may arise from an immediate or mediated adaptive metabolic response of the perinatal growth. Evidence on the cumulative effects of growth and factors associated with risk of insulin resistance in adolescents is lacking.

OBJECTIVE

To investigate the association between birthweight, weight gain during infancy, childhood and adolescence and the triglyceride-glucose index in adolescents.

METHODS

This is a cohort of 217 children born at term, followed for the first six months, and reassessed at 8 and 18 years of age. The variables of interest were birthweight, postnatal growth defined as rapid postnatal growth when the weight gain from birth to six months of age was greater than 0.67 z-score, and the same criterion was used for high BMI gain from ages 6 months to 8 years, and from 8 to 18 years. Socioeconomic condition, nutritional status, practice of physical exercises and consumption of ultra-processed foods were verified. Multivariate linear regression analysis was used to verify the effect of the variables on the triglyceride-glucose index.

RESULTS

Birthweight was not associated with triglyceride-glucose index in adolescence. Rapid postnatal growth during the first 6 months, higher BMI gain from 8 to 18 years and higher waist circumference contributed significantly to explain higher triglyceride-glucose index.

CONCLUSION FOR PRACTICE

Our findings suggest that rapid postnatal growth may be one of the first signs of a higher triglyceride-glucose index in adolescence and that attention should be paid to the greater gain in body mass between childhood and adolescence for the risk of a higher triglyceride-glucose index.

Influence of Sociodemographic Variables and Healthy Habits on the Values of Insulin Resistance Indicators in 386,924 Spanish Workers

BACKGROUND

Insulin resistance (IR) is an alteration of the action of insulin in cells, which do not respond adequately to this action, leading to an increase in blood glucose levels. IR produces a very diverse clinical picture and increases the cardiometabolic risk of the population that suffers from it. Among the factors that influence IR are genetics, unhealthy lifestyle habits, overweight, and obesity. The objective of this work was to determine how different sociodemographic variables and healthy habits influence the values of different scales that assess the risk of presenting IR in a group of Spanish workers.

METHODS

An observational, cross-sectional, descriptive study was carried out in 386,924 workers from different Spanish regions. Different sociodemographic variables and lifestyle habits were studied (age, social class, educational level, smoking, Mediterranean diet, physical exercise) along with their association with four scales to evaluate the risk of insulin resistance (TyG index, TyG-BMI, METS-IR, TG/HDL-c). To analyse the quantitative variables, Student's t test was used, while the Chi-squared test was used for the qualitative variables. A multinomial logistic regression analysis was performed, calculating the odds ratio with its 95% confidence intervals. The accepted level of statistical significance was set at p < 0.05.

RESULTS

In the multivariate analysis, all variables, except educational level, increased the risk of presenting high values on the IR risk scales, especially a sedentary lifestyle and low adherence to the Mediterranean diet.

CONCLUSIONS

Our results demonstrate an association between the practice of regular physical exercise and a reduction in the risk of IR; a strong role of the Mediterranean diet as a protective factor for IR; an association between aging and increased IR, which has also been suggested in other studies; and, finally, a relationship between a low socioeconomic level and an increase in IR.

Relationship between Abdominal Volume Index and Body Adiposity Index and Scales of Insulin Resistance and Metabolic Syndrome

Introduction, objectives: Obesity is a global health problem with a great negative impact on health. Among the pathologies caused by obesity are insulin resistance and metabolic syndrome, which constitute an increasingly common health problem in both developed and developing countries. The aim of this study was to examine the relationship between two scales that assess obesity-based on hip circumference-and metabolic syndrome (MetS) and insulin resistance risk scales as predictors of these alterations.

MATERIALS, METHODS

A descriptive, cross-sectional study was carried out on 193,462 workers from different Spanish regions and work groups between January 2019 and September 2021. Abdominal volume index (AVI) and body adiposity index (BAI) were evaluated to assess obesity and its association with insulin resistance using three risk scales (TyG index, Triglycerides/HDL, and METS-IR), while their association with metabolic syndrome was determined using the NCEP ATP III, IDF, and JIS models.

RESULTS

The results of the ROC curves to determine the predictive value of BAI and AVI in relation to the three criteria evaluated to calculate MetS in all instances presented a higher area under the curve (AUC) for AVI. The high values of AVI stand out for predicting MetS when applying the IDF criteria. The cut-off point in women was 13.70 with a Youden index of 0.802, whereas in men, the cut-off point was set at 17.59 with a Youden index of 0.672. Regarding the relationship of BAI and AVI with insulin resistance risk scales for both sexes, the AUC only revealed high values when using the METS-IR formula for both AVI and BAI. The AVI cut-off points to predict high values of insulin resistance risk scales in women were established at 13.12 with a Youden index of 0.722. In men, the cut-off point was 17.59, with a Youden index of 0.626. The BAI cut-off points in women were set at 33.88 with a Youden index of 0.748. In men, the cut-off point was 27.91, with a Youden index of 0.598.

CONCLUSIONS

AVI demonstrated its value as a predictor of metabolic syndrome while exclusively applying the IDF criteria. AVI and BAI demonstrated their value as predictors of high values of insulin resistance risk scales only in the case of METS-IR. This predictive value is also higher in women.

Aging Affects Insulin Resistance, Insulin Secretion, and Glucose Effectiveness in Subjects with Normal Blood Glucose and Body Weight

AIM

Several studies have demonstrated that factors including diabetes, including insulin resistance (IR), glucose effectiveness (GE), and the first and second phase of insulin secretion (FPIS, SPIS) could easily be calculated using basic characteristics and biochemistry profiles. Aging is accompanied by deteriorations of insulin resistance (IR) and insulin secretion. However, little is known about the roles of aging in the different phases of insulin secretion (ISEC), i.e., the first and second phase of insulin secretion (FPIS, SPIS), and glucose effectiveness (GE).

METHODS

In total, 169 individuals (43 men and 126 women) recruited from the data bank of the Meei-Jaw (MJ) Health Screening Center and Cardinal Tien Hospital Data Access Center between 1999 and 2008, with a similar fasting plasma glucose (FPG: 90 mg/dL) and BMI (men: 23 kg/m², women 22 kg/m²) were enrolled. The IR, FPIS, SPIS, and GE were estimated using our previously developed equations shown below. Pearson correlation analysis was conducted to assess the correlations between age and four diabetes factors (DFs: IR, FPIS, SPIS, and GE). The equations that are used to calculate the DF in the present study were built and published by our group.

RESULTS

The age of the participants ranged from 18 to 78 years. Men had higher FPIS but lower HDL-C levels than women (2.067 ± 0.159, 1.950 ± 0.186 μU/min and 1.130 ± 0.306, 1.348 ± 0.357 mmol/dl, accordingly). The results of the Pearson correlation revealed that age was negatively related to the IR and GE in both genders (IR: r = -0.39, p < 0.001 for men, r = -0.24, p < 0.003 for women; GE: r = 0.66, p < 0.001 for men, r = 0.78, p < 0.001 for women). At the same time, the FPIS was also only found to be negatively correlated with age in females (r = -0.238, p = 0.003), but there was no difference in the SPIS and age among both genders.

CONCLUSIONS

We have found that in Chinese subjects with a normal FPG level (90 mg/dL) and body mass index (men: 23 kg/m², women: 22: kg/m²), age is negatively related to the IR and GE among both genders. Only the FPIS was found to be negatively related to age in women. The tightness of their relationships, from the highest to the lowest, are GE, FPIS, and IR. These results should be interpreted with caution because of the small sample size.

Mechanistic insights into the beneficial effects of curcumin on insulin resistance: opportunities and challenges

The past couple of decades in particular have seen a rapid increase in the prevalence of type 2 diabetes mellitus (T2DM), a debilitating metabolic disorder characterised by insulin resistance. The insufficient efficacy of current management strategies for insulin resistance calls for additional therapeutic options. The preponderance of evidence suggests potential beneficial effects of curcumin on insulin resistance, while modern science provides a scientific basis for its potential applications against the disease. Curcumin combats insulin resistance by increasing the levels of circulating irisin and adiponectin, activating PPARγ, suppressing Notch1 signalling, and regulating SREBP target genes, among others. In this review, we bring together the diverse areas pertaining to our current understanding of the potential benefits of curcumin on insulin resistance, associated mechanistic insights, and new therapeutic possibilities. Teaser: Current approaches to manage insulin resistance are not highly efficacious, which necessitates additional therapeutic options; curcumin combats insulin resistance by improving the levels of circulating irisin and adiponectin, upregulating and activating PPARγ, and suppressing Notch‑1 signalling.

FGF1 ameliorates obesity-associated hepatic steatosis by reversing IGFBP2 hypermethylation

Obesity is a major contributing factor for metabolic-associated fatty liver disease (MAFLD). Fibroblast growth factor (FGF) 1 is the first paracrine FGF family member identified to exhibit promising metabolic regulatory properties capable of conferring glucose-lowering and insulin-sensitizing effect. This study explores the role and molecular underpinnings of FGF1 in obesity-associated hepatic steatosis. In a mouse high-fat diet (HFD)-induced MAFLD model, chronic treatment with recombinant FGF1(rFGF1) was found to effectively reduce the severity of insulin resistance, hyperlipidemia, and inflammation. FGF1 treatment decreased lipid accumulation in the mouse liver and palmitic acid-treated AML12 cells. These effects were associated with decreased mature form SREBF1 expression and its target genes FASN and SCD1. Interestingly, we uncovered that rFGF1 significantly induced IGFBP2 expression at both mRNA and protein levels in HFD-fed mouse livers and cultured hepatocytes treated with palmitic acid. Adeno-associated virus-mediated IGFBP2 suppression significantly diminished the therapeutic benefit of rFGF1 on MAFLD-associated phenotypes, indicating that IGFBP2 plays a crucial role in the FGF1-mediated reduction of hepatic steatosis. Further analysis revealed that rFGF1 treatment reduces the recruitment of DNA methyltransferase 3 alpha to the IGFBP2 genomic locus, leading to decreased IGFBP2 gene methylation and increased mRNA and protein expression. Collectively, our findings reveal FGF1 modulation of lipid metabolism via epigenetic regulation of IGFBP2 expression, and unravel the therapeutic potential of the FGF1-IGFBP2 axis in metabolic diseases associated with obesity.

Pancreatic β-cell dysfunction in type 2 diabetes: Implications of inflammation and oxidative stress

Insulin resistance and pancreatic β-cell dysfunction are major pathological mechanisms implicated in the development and progression of type 2 diabetes (T2D). Beyond the detrimental effects of insulin resistance, inflammation and oxidative stress have emerged as critical features of T2D that define β-cell dysfunction. Predominant markers of inflammation such as C-reactive protein, tumor necrosis factor alpha, and interleukin-1β are consistently associated with β-cell failure in preclinical models and in people with T2D. Similarly, important markers of oxidative stress, such as increased reactive oxygen species and depleted intracellular antioxidants, are consistent with pancreatic β-cell damage in conditions of T2D. Such effects illustrate a pathological relationship between an abnormal inflammatory response and generation of oxidative stress during the progression of T2D. The current review explores preclinical and clinical research on the patho-logical implications of inflammation and oxidative stress during the development of β-cell dysfunction in T2D. Moreover, important molecular mechanisms and relevant biomarkers involved in this process are discussed to divulge a pathological link between inflammation and oxidative stress during β-cell failure in T2D. Underpinning the clinical relevance of the review, a systematic analysis of evidence from randomized controlled trials is covered, on the potential therapeutic effects of some commonly used antidiabetic agents in modulating inflammatory makers to improve β-cell function.

Role of Insulin Resistance as a Mediator of the Relationship between Body Weight, Waist Circumference, and Systolic Blood Pressure in a Pediatric Population

Excess weight and high waist circumference (WC) are associated with increased blood pressure (BP), starting from the pediatric age. Insulin resistance is associated with elevated BP in childhood. The aim of the study was to assess the role of insulin resistance in mediating the relationship between body mass index (BMI), WC, and BP values in a pediatric population referred to a cardio-pediatric center for the presence of one or more cardiovascular risk factors. In 419 children (mean age 10.7 [standard deviation, SD 2.5] years), the following parameters were collected both in basal conditions and after 18.6 (SD 9.3) months of follow-up during which a treatment based on lifestyle and dietary modifications was given: systolic and diastolic BP (SBP and DBP), WC, plasma glucose, and insulin values. The HOMA (Homeostasis Model Assessment)-index was considered as an expression of insulin resistance. At baseline there was a significant correlation between HOMA-index and SBP z-score (β = 0.081, p = 0.003), and insulin resistance was a mediator of the relationship between BMI and SBP z-score (p = 0.015), and between waist circumference to height (WtHr) and SBP z-score (p = 0.008). The effect of BMI z-score modifications on SBP z-score changes from baseline to follow-up was totally mediated by HOMA-index changes (p = 0.008), while HOMA-index only partially mediated the effect of WtHr modifications on SBP z-score changes (p = 0.060). Our study strongly suggests that, in a pediatric population at cardiovascular risk, the HOMA-index is an important mediator of the relationship between BMI, WC and SBP.

From New Endocrine Entities Requiring New Approaches to New Approaches Leading to New Endocrine Entities

The dynamics pace of modern society is reflected by the medical community, the public health concerns, the quality of life, as well as the specific spectrum of various disorders [...].