Differences between men and women in the regulation of adipose 11β-HSD1 and in its association with adiposity and insulin resistance

This study explored sex differences in 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity and gene expression in isolated adipocytes and adipose tissue (AT), obtained via subcutaneous biopsies from non-diabetic subjects [58 M, 64 F; age 48.3 ± 15.3 years, body mass index (BMI) 27.2 ± 3.9 kg/m²]. Relationships with adiposity and insulin resistance (IR) were addressed. Males exhibited higher 11β-HSD1 activity in adipocytes than females, but there was no such difference for AT. In both men and women, adipocyte 11β-HSD1 activity correlated positively with BMI, waist circumference, % body fat, adipocyte size and with serum glucose, triglycerides and low-density lipoprotein:high-density lipoprotein (LDL:HDL) ratio. Positive correlations with insulin, HOMA-IR and haemoglobin A1c (HbA1c) and a negative correlation with HDL-cholesterol were significant only in males. Conversely, 11β-HSD1 activity in AT correlated with several markers of IR and adiposity in females but not in males, but the opposite pattern was found with respect to 11β-HSD1 mRNA expression. This study suggests that there are sex differences in 11β-HSD1 regulation and in its associations with markers of obesity and IR.

Hydrochlorothiazide compared to candesartan treatment increases adipose tissue gene expression and circulating levels of serum amyloid A in hypertensive patients

Treatment of hypertension with angiotensin receptor blockers has been shown to reduce the risk of developing type 2 diabetes in comparison to thiazide diuretics and beta adrenergic blockers. Therefore, we wanted to study the effect of antihypertensive drugs on adipose tissue with respect to insulin resistance. In the MEDICA (MEchanisms for the DIabetes preventing effects of CAndesartan) study, 22 hypertensive, nondiabetic patients with abdominal obesity (10 men, 12 women) were randomized into 12-week treatment periods with candesartan, hydrochlorothiazide, and placebo according to a 3-way cross-over design. Subcutaneous adipose tissue biopsies were taken after 8 weeks treatment to analyze gene expression, glucose uptake capacity, insulin-signaling, and adipocyte size. Adipose tissue gene expression of serum amyloid A (SAA) was higher after hydrochlorothiazide treatment compared to candesartan (p=0.036), and this was in accordance with our previous finding on circulating SAA levels. Serum levels of E selectin were increased after hydrochlorothiazide compared to candesartan treatment (p=0.002) and lower after candesartan compared to placebo (p=0.002). In adipocytes, there were no significant differences between the treatments with respect to cell size, glucose uptake capacity, or insulin-signaling. In comparison to candesartan, hydrochlorothiazide raised the adipose tissue gene expression of SAA and the serum level of SAA as well as E selectin in hypertensive patients. Less adipose and systemic inflammation may be one explanation why candesartan is favorable in comparison to thiazide diuretics with respect to development of insulin resistance and type 2 diabetes.

Repeated measurements of 11β-HSD-1 activity in subcutaneous adipose tissue from lean, abdominally obese, and type 2 diabetes subjects--no change following a mixed meal

The aim of this study was to measure 11β-HSD-1 activity in subcutaneous adipose tissue by an ex vivo method in three subgroups; lean, obese, and type 2 diabetes subjects, both in the fasting state and after a mixed meal and to determine the variability and reproducibility of this method. Eighteen subjects were investigated; 6 lean, 6 abdominally obese, and 6 type 2 diabetes subjects (BMI 22 ± 1, 30 ± 3 and 31 ± 3 kg/m², respectively). Needle biopsies were taken repeatedly and an index of 11β-HSD-1 activity was measured as percent conversion of (3)H-cortisone to (3)H-cortisol/100 mg tissue. For two separate biopsies taken in the fasting state on the same day, the within subjects CV was 16% and the between CV was 36% for 11β-HSD-1 activity for all subjects. For two biopsies taken in the fasting state at two different days, the total within subjects CV was 38% and the between subjects CV was 46%. Lean subjects had lower 11β-HSD-1 activity (4.8 ± 1.5% conversion of ³H-cortisone to ³H-cortisol/100 mg tissue) than both obese (14.4 ± 1.6% conversion, p<0.01) and type 2 diabetes subjects (11.7 ± 1.9% conversion, p<0.05) in the fasting state. There was no effect of a meal on 11β-HSD-1 activity in any of the three groups. The conclusions from this study are: 1) the variation coefficient for the ex vivo adipose tissue 11β-HSD-1 activity method was ∼25% for repeat measures within subjects; 2) food intake had no major impact on enzyme activity; and 3) 11β-HSD-1 activity in subcutaneous adipose tissue was significantly increased in obese subjects with or without T2DM compared to lean subjects without diabetes.