Resistin levels decrease as insulin resistance increases in a Mexican-American cohort

The Association of Resistin with Metabolic Health and Obesity in a Mexican-American Population

Research on the relationship between resistin levels, metabolic health, and obesity has produced inconsistent findings across different ethnic groups, making it unclear whether lower resistin levels are associated with these conditions in Mexican-Americans. This cross-sectional study investigated the relationship between resistin, metabolic health, and obesity in an adult Mexican-American cohort (n = 1511) using multivariable linear regression analysis. Related adipokines (leptin and adiponectin) were measured simultaneously. Participants were categorized into four groups by metabolic health (healthy/unhealthy) and obesity (obese/non-obese) status. "Metabolically unhealthy" was defined as ≥2 cardiometabolic abnormalities. Obesity was defined as a BMI ≥ 30 kg/m2. We also investigated the associations of related proinflammatory cytokines, demographic/anthropometric variables, and medications with each outcome variable of interest. The results showed no statistically significant differences in resistin levels between the groups. Leptin was higher and adiponectin was lower in groups with obesity and/or metabolically unhealthy status. The resistin findings contrast studies in other populations, while other leptin and adiponectin findings confirm those seen in many ethnic groups. Thiazolidinedione use was associated with lower resistin, confirming earlier research. These findings suggest that resistin's role in metabolic health may be different in Mexican-Americans compared to other populations.

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

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

Sex-specific associations between adipokine profiles and carotid-intima media thickness in the Cameron County Hispanic Cohort (CCHC)

BACKGROUND

Adipokines are hormones secreted from adipose tissue and are associated with cardiometabolic diseases (CMD). Functional differences between adipokines (leptin, adiponectin, and resistin) are known, but inconsistently reported associations with CMD and lack of studies in Hispanic populations are research gaps. We investigated the relationship between subclinical atherosclerosis and multiple adipokine measures.

METHODS

Cross-sectional data from the Cameron County Hispanic Cohort (N = 624; mean age = 50; Female = 70.8%) were utilized to assess associations between adipokines [continuous measures of adiponectin, leptin, resistin, leptin-to-adiponectin ratio (LAR), and adiponectin-resistin index (ARI)] and early atherosclerosis [carotid-intima media thickness (cIMT)]. We adjusted for sex, age, body mass index (BMI), smoking status, cytokines, fasting blood glucose levels, blood pressure, lipid levels, and medication usage in the fully adjusted linear regression model. We conducted sexes-combined and sex-stratified analyses to account for sex-specificity and additionally tested whether stratification of participants by their metabolic status (metabolically elevated risk for CMD as defined by having two or more of the following conditions: hypertension, dyslipidemia, insulin resistance, and inflammation vs. not) influenced the relationship between adipokines and cIMT.

RESULTS

In the fully adjusted analyses, adiponectin, leptin, and LAR displayed significant interaction by sex (p < 0.1). Male-specific associations were between cIMT and LAR [β(SE) = 0.060 (0.016), p = 2.52 × 10-4], and female-specific associations were between cIMT and adiponectin [β(SE) = 0.010 (0.005), p = 0.043] and ARI [β(SE) = - 0.011 (0.005), p = 0.036]. When stratified by metabolic health status, the male-specific positive association between LAR and cIMT was more evident among the metabolically healthy group [β(SE) = 0.127 (0.015), p = 4.70 × 10-10] (p for interaction by metabolic health < 0.1). However, the female-specific associations between adiponectin and cIMT and ARI and cIMT were observed only among the metabolically elevated risk group [β(SE) = 0.014 (0.005), p = 0.012 for adiponectin; β(SE) = - 0.015 (0.006), p = 0.013 for ARI; p for interaction by metabolic health < 0.1].

CONCLUSION

Associations between adipokines and cIMT were sex-specific, and metabolic health status influenced the relationships between adipokines and cIMT. These heterogeneities by sex and metabolic health affirm the complex relationships between adipokines and atherosclerosis.