Relationship of adipokines with insulin sensitivity in African Americans.

INTRODUCTION: Cytokines produced by adipose tissue, including adiponectin, have been associated with metabolic abnormalities. The purpose of this study was to examine the relationship of insulin sensitivity measured by euglycemic hyperinsulinemic insulin clamp with plasma adiponectin and other adipokines in young adult African Americans. METHODS: Participants were healthy African Americans. Anthropometric measures, blood pressure, an oral glucose tolerance test and an euglycemic hyperinsulinemic insulin clamp were performed. Insulin sensitivity measurements were adjusted for percentage of fat mass. Plasma concentrations of adiponectin, plasminogen activator inhibitor-1 (PAI-1) and interleukin-6 (IL-6) were assayed on plasma from fasting blood samples. Pearson correlation coefficients and multiple regression models were fitted to assess the association between glucose sensitivity and cytokines. RESULTS: In univariate analysis, there were statistically significant correlations of plasma adiponectin level (r = 0.19, P = 0.004), PAI-1 (r = -0.19, P = 0.020) and IL-6 (r = -0.24, P \u3c 0.001) with measures of insulin sensitivity after adjustment for both fat mass and insulin clamp concentration. In multivariate analysis, adiponectin [geometric mean ratios (GMR) 1.15, P = 0.007], PAI-1 (GMR 0.998, P = 0.021) and body mass index (GMR 0.95, P \u3c 0.001) were each independently associated with insulin sensitivity. For IL-6, there was no significant association with insulin sensitivity independent of obesity. CONCLUSION: These data show a significant and independent positive correlation of adiponectin with insulin sensitivity. The relationship of IL-6 with insulin sensitivity seems to be dependent on adiposity

Associations of cardiac structure with obesity, blood pressure, inflammation, and insulin resistance in African-American adolescents.

To determine if obesity, blood pressure (BP), markers of inflammation, and insulin resistance are associated with cardiac structure in African-American adolescents, a cross-sectional study was performed on a cohort oversampled for high BP and obesity. Measurements included the following: anthropometrics, BP, homeostasis model assessment (HOMA) to assess insulin resistance, high-sensitivity C-reactive protein, and plasma adipokines (adiponectin, interleukin-6, plasminogen activator inhibitor-1). Echocardiogram measurements were left-ventricular mass index (LVMI) (g/m(2.7)), LV relative wall thickness (LVRWT), left-atrial diameter index [LADI (mm/m)], and LV diastolic time intervals. LADI (r (2) = 0.25) was associated with body mass index (BMI) systolic BP (SBP) and female sex. LVMI (r (2) = 0.35) variation was associated with BMI SBP, heart rate, age, and male sex. LVRWT (r (2) = 0.05) was associated with HOMA. Tissue diastolic intervals were not associated with any risk factor. Inflammatory markers and adipokines were associated with BMI but were not independently associated with any echocardiographic measures. In African-American adolescents, BMI and SBP, but not inflammatory markers or adipokines, are important correlates of LA size and LVM

Associations of cardiac structure with obesity, blood pressure, inflammation, and insulin resistance in African-American adolescents.

To determine if obesity, blood pressure (BP), markers of inflammation, and insulin resistance are associated with cardiac structure in African-American adolescents, a cross-sectional study was performed on a cohort oversampled for high BP and obesity. Measurements included the following: anthropometrics, BP, homeostasis model assessment (HOMA) to assess insulin resistance, high-sensitivity C-reactive protein, and plasma adipokines (adiponectin, interleukin-6, plasminogen activator inhibitor-1). Echocardiogram measurements were left-ventricular mass index (LVMI) (g/m(2.7)), LV relative wall thickness (LVRWT), left-atrial diameter index [LADI (mm/m)], and LV diastolic time intervals. LADI (r (2) = 0.25) was associated with body mass index (BMI) systolic BP (SBP) and female sex. LVMI (r (2) = 0.35) variation was associated with BMI SBP, heart rate, age, and male sex. LVRWT (r (2) = 0.05) was associated with HOMA. Tissue diastolic intervals were not associated with any risk factor. Inflammatory markers and adipokines were associated with BMI but were not independently associated with any echocardiographic measures. In African-American adolescents, BMI and SBP, but not inflammatory markers or adipokines, are important correlates of LA size and LVM

Variants in genes involved in functional pathways associated with hypertension in African Americans.

Essential hypertension (HBP) is a complex trait with a substantial heritable component. The purpose of this study was to determine if variants in the G-protein coupled receptor Kinase-4 (GRK4), nitric oxide synthase-3 (NOS3), or angiotensin converting enzyme (ACE) genes are associated singly or through complex interactions, with HBP in African Americans aged 18-49 years. TaqMan Assays were used for genotyping the GRK4 and NOS3 variants. The ACE I/D variant was obtained by polymerase chain reaction and electrophoresis. Allelic association tests were performed for the five markers using PLINK. Logistic regression models were fitted to investigate associations between HBP status and the genetic markers. Multilocus analyses were also conducted. The study included 173 hypertensives and 239 normotensives, with stratification into obese and nonobese groups. The GRK4 A486V variant was negatively associated with HBP in the nonobese group (p = 0.048). The TT/CT genotype of GRK4 A486V was associated with decreased risk for HBP relative to the CC genotype after adjusting for age, sex, and body mass index (p = 0.028). Individuals having at least one NOS3 A allele and GRK4 R65L genotype GG had odds of HBP of 2.97 relative to GG homozygotes for NOS3 and GRK4 R65L. These results show very modest effects and do not fully replicate previous studies. © 2010 Wiley Periodicals, Inc