The effect of physiologic hyperinsulinemia during an oral glucose tolerance test on the levels of dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) in healthy young adults born with low and with normal birth weight

Cardiovascular Risk Factors and Dehydroepiandrosterone Sulfate Among Latinos in the Boston Puerto Rican Health Study

Low blood dehydroepiandrosterone sulfate (DHEAS) levels have strong positive associations with stroke and coronary heart disease. However, it is unclear whether DHEAS is independently associated with cardiovascular risk factors. Therefore, we examined the association between cardiovascular risk factors and DHEAS concentration among a high-risk population of Latinos (Puerto Ricans aged 45 to 75 years at baseline) in a cross-sectional analysis of the Boston Puerto Rican Health Study. Of eligible participants, 72% completed baseline interviews and provided blood samples. Complete data were available for 1355 participants. Associations between cardiovascular risk factors (age, sex, total cholesterol, high-density lipid cholesterol, triglycerides, and glucose) and log-transformed DHEAS (μg/dL) were assessed. In robust multivariable regression analyses, DHEAS was significantly inversely associated with age (β = -12.4; 95% CI: -15.2, -9.7; per 5 years), being female (vs. male) (β = -46; 95% CI: -55.3, -36.6), and plasma triglyceride concentration (β = -0.2; 95% CI: -0.3, -0.1; per 10 mg/dL) and was positively associated with total cholesterol and plasma glucose levels (β = 1.8; 95% CI: 0.6, 3 and β = 0.2; 95% CI: 0.04, 0.3, respectively, per 10 mg/dL) after adjustment for smoking, alcohol, and physical activity and for postmenopausal hormone use in women. Estimates were unchanged after adjustment for measures of chronic disease and inflammation. Women exhibited a stronger age-related decline in DHEAS and a positive association with glucose in contrast to findings among men (P _interaction < 0.05). In conclusion, in this large study of Latinos with a heavy cardiovascular risk factor burden, we observed significant associations between cardiovascular disease (CVD) risk factors and DHEAS, with variations by sex. These findings improve our understanding of the role DHEAS may play in CVD etiology.

Soluble Receptor for Advanced Glycation End Products Improves Stromal Cell-Derived Factor-1 Activity in Model Diabetic Environments

Objective: In diabetes, hyperglycemia causes the accumulation of advanced glycation end products (AGEs) that trigger reactive oxygen species (ROS) generation through binding the receptor for AGEs (RAGE). Because exogenous growth factors have had little success in enhancing chronic wound healing, we investigated whether hyperglycemia-induced AGEs interfere with cellular responses to extracellular signals. We used stromal cell-derived factor-1 (SDF-1), an angiogenic chemokine also known to promote stem cell recruitment in skin wounds. Approach: Human leukemia-60 (HL-60) cells and mouse peripheral blood mononuclear cells (PBMCs), which express the SDF-1 receptor CXCR-4, were incubated for 24 h in medium supplemented with 25 mM d-glucose. Soluble RAGE (sRAGE) was used to block RAGE activation. Response to SDF-1 was measured in cellular migration and ROS assays. A diabetic murine excisional wound model measured SDF-1 liposome and sRAGE activity in vivo. Results: Hyperglycemia led to significant accumulation of AGEs, decreased SDF-1-directed migration, and elevated baseline ROS levels; it suppressed the ROS spike normally triggered by SDF-1. sRAGE decreased the ROS baseline and restored both the SDF-1-mediated spike and cell migration. Topically applied sRAGE alone promoted healing and enhanced the effect of exogenous SDF-1 on diabetic murine wounds. Innovation: While there is interest in using growth factors to improve wound healing, this strategy is largely ineffective in diabetic wounds. We show that sRAGE may restore signaling, thus potentiating the effect of exogenously applied growth factors. Conclusion: Blocking RAGE with sRAGE restores SDF-1-mediated cellular responses in hyperglycemic environments and may potentiate the effectiveness of SDF-1 applied in vivo.

Effect of sex steroids and insulin on dehydroepiandrosterone sulfate production by hepatoma G2 cells

OBJECTIVE

To test the hypothesis that DHEAS production from DHEA occurs in hepatic cells and that this production is augmented by the presence of sex steroids or insulin.

DESIGN

In vitro prospective experiment.

SETTING

Academic medical center.

INTERVENTION(S)

Hepatoma G2 cells cultured in media supplemented with [1] DHEA (10(-5) mol/L) only, [2] DHEA (10(-5) mol/L) + T (10(-6) mol/L), [3] DHEA (10(-5) mol/L) + E(2) (10(-6) mol/L), [4] DHEA (10(-5) mol/L) + dihydrotestosterone (10(-6) mol/L), [5] DHEA (10(-5) mol/L) + insulin (10 ng/mL), or [6] DHEA (10(-5) mol/L) + insulin (100 ng/mL).

MAIN OUTCOME MEASURE(S)

Levels of DHEAS in the media were measured at 0, 2, 4, 6, 8, 12, 24, 48, and 72 hours after adding treatments at time-point 0.

RESULT(S)

Dehydroepiandrosterone sulfate was first detected in the hepatoma G2 cell culture media at 12 hours of incubation. The cumulative production rate of DHEAS increased linearly until 72 hours of incubation. When compared with the effect of treatment with DHEA only, treatment with DHEA plus T, dihydrotestosterone, or E(2) delayed the cumulative DHEAS production; alternatively, the addition of insulin did not alter DHEAS production.

CONCLUSION(S)

These data suggest that although hepatic cells have the ability of converting DHEA to DHEAS, neither sex steroids nor insulin results in the increased hepatic production of DHEAS.