Impact of physical inactivity on adipose tissue low-grade inflammation in first-degree relatives of type 2 diabetic patients.

OBJECTIVE: First-degree relatives (FDRs) of patients with type 2 diabetes may exhibit a disproportionately elevated risk of developing insulin resistance, obesity, and type 2 diabetes when exposed to physical inactivity, which to some unknown extent may involve low-grade inflammation. We investigated whether subjects who are nonobese FDRs show signs of low-grade inflammation before or after exposure to short-term physical inactivity. RESEARCH DESIGN AND METHODS: We studied 13 healthy FDR subjects and 20 control (CON) subjects matched for age, sex, and BMI before and after 10 days of bed rest (BR). Insulin sensitivity was measured by the hyperinsulinemic euglycemic clamp. Key low-grade inflammation mediators were measured in arterial blood and microdialysate from subcutaneous abdominal (SCAAT) and femoral adipose tissue. Adipokine mRNA expression was determined in SCAAT. RESULTS: Before BR, FDR subjects displayed insulin resistance, elevated plasma C-reactive protein, leptin, and monocyte chemoattractant protein (MCP)-1, high interleukin (IL)-6, and MCP-1 expressions, as well as low adiponectin and leptin expressions. FDR subjects responded to BR by decreasing plasma adiponectin and IL-10 expression and increasing plasma expression of IL-10 and tumor necrosis factor-α. In contrast, CON subjects responded to BR by increasing plasma adiponectin and adiponectin expression and by decreasing SCAAT microdialysate leptin. CONCLUSIONS: Young and nonobese FDR of patients with type 2 diabetes exhibit low-grade inflammation, which is further and disproportionately aggravated when exposed to physical inactivity. The study provides support for the notion that people at increased risk of type 2 diabetes should avoid even short periods of physical inactivity.

Interstitial concentrations of adipokines in subcutaneous abdominal and femoral adipose tissue.

Adipokines play important regulatory roles in the pathophysiology of obesity and insulin resistance. We measured plasma and interstitial concentrations of the adipokines adiponectin, resistin, leptin, monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6) and interleukin-8 (IL-8) in subcutaneous, abdominal and femoral adipose tissue using calibrated, large-pore microdialysis technique in 8 healthy, lean men on 2 experimental days. The interstitial leptin concentration was 2.5-fold higher in subcutaneous, femoral than abdominal adipose tissue (P<0.05), but no regional differences were found for the remaining adipokines (P>0.05). Adiponectin and leptin concentrations were higher in plasma than subcutaneous adipose tissue (approximately 25-fold and approximately 2-fold, respectively, P<0.05), whereas MCP-1, IL-6 and IL-8 concentrations were higher in subcutaneous adipose tissue than plasma (approximately 100-fold, approximately 200-fold and approximately 1000-fold, respectively, P<0.05). Resistin concentrations did not differ significantly between compartments. Adipose tissue blood flow (ATBF) showed no regional difference (P>0.05). The intra- and inter-subject variations of all investigated adipokines as well as of ATBF were substantial (coefficient of variation: 4-177%). In conclusion, interstitial leptin concentrations are approximately 2.5-fold higher in subcutaneous, femoral than abdominal adipose tissue, which might be a potential mechanism behind the health-benefits of "pear-shape". Furthermore, subcutaneous adipose tissue has a marked production of pro-inflammatory adipokines.

Effects of physical training on endothelial function and limb blood flow in type 2 diabetes.

The term "endothelial dysfunction" refers to the inability or attenuated effect of the endothelial cells in participating in the relaxation of the adjacent smooth muscle, thus causing less vasodilation. Although endothelial dysfunction is often seen in patients with type 2 diabetes, it does not necessarily follow that insulin resistance and (or) hyperglycemia is causing the inability to respond properly to vasodilatory stimuli. Rather, this could be related to the impact of concomitant cardiovascular risk factors that are almost invariably present in patients with type 2 diabetes. The impact of physical training - or the opposite, inactivity - on endothelial function is not fully elucidated. Some studies have shown positive effects of physical training, whereas others have not. In general, physical training can improve endothelial function when this is impaired. However, physical training does not seem to have any effect on endothelial function when this is normal.