Subcutaneous and Visceral Fat: Relation with Brown Adipose Tissue Activation in Women.

Brown adipose tissue (BAT) helps control body weight and is inversely correlated with body fat, but it is unclear whether it is subcutaneous adipose tissue (SAT) or visceral adipose tissue (VAT) that is related to BAT activation. The presented study aimed to verify the relation of SAT and VAT on BAT activation through infrared thermography (IRT) and cold stimulation in adult women. Forty women were evaluated in body composition and skin temperature (Tskin) acquisition by IRT. Student's independent t-test, Pearson's correlation, and two-way repeated measures ANOVA with Tukey post-hoc were applied. Women with low amounts of SAT and VAT had a significant increase in supraclavicular Tskin (SCVT). Medium negative degrees of linear variation were found before and after cold stimulation between SCVT, SAT and VAT. A significant effect of the moment factor and the group factor on the SCVT between subjects divided into the groups were pointed out. No difference was found in the relation between SAT, VAT, and BAT in adult women, pointing out that both types of fat are equally related. These results can help clinical practice understand clearly, through IRT, that the high accumulation of SAT and VAT can impair the activation of BAT and hinder the loss of weight in women.

Comparison of brown adipose tissue activation detected by infrared thermography in men with vs without metabolic syndrome.

BACKGROUND: Brown adipose tissue (BAT) high density of mitochondria and its thermogenic characteristics promote the dissipation of chemical energy in the form of heat, increasing body caloric expenditure, decreasing plasma levels of lipids and glucose (GL). This makes BAT a potential therapeutic target of Metabolic Syndrome (MetS). Position Emission Tomography Scanning (PET-CT) is the gold standard for estimating BAT, but it has several limitations, including high cost and high emission of radiation. On the other hand, Infrared Thermography (IRT) is considered a simpler, cheaper and non-invasive method to detect BAT. OBJECTIVE: The aim of this study was to compare BAT activation through IRT and cold stimulation in men diagnosed without and with MetS. METHODS: Sample of 124 (35.3 ± 9.4 years old) men was evaluated of body composition, anthropometric measurements and dual X-ray absorptiometry (DXA) hemodynamics, biochemical tests and body skin temperature acquisition. The Student t-test with subsequent effect size by (d) Cohen and two-way repeated measures ANOVA with Tukey post-hoc comparisons were conducted. Level of significance was p < 0.05. RESULTS: There was significant interaction between group factor (MetS) vs group moment (BAT activation) in supraclavicular skin temperatures right side (maximum (F(1,122) = 10.4, p < 0.002, η2 = 0.062), mean (F(1.122) = 13.0, p < 0.001, η2 = 0.081) and minimal (F(1,122) = 7.9, p < 0.006, η2 = 0.052)) and left side maximum (F(1,122) = 7.7, p < 0.006, η2 = 0.048), mean (F(1.122) = 13.0, p < 0.037, η2 = 0.007) and minimal (F(1,122) = 9.8, p < 0.002, η2 = 0.012)). The MetS risk factor group didn't present significant increase of SCV temperature BAT after cold stimulation. CONCLUSION: Men diagnosed with MetS risk factors seem to activate less BAT, when exposed to cold stimulation, compared to group without MetS risk factor.