Inhibition of adipose tissue PPARγ prevents increased adipocyte expansion after lipectomy and exacerbates a glucose-intolerant phenotype.

OBJECTIVES: Adipose tissue plays a fundamental role in glucose homeostasis. For example, fat removal (lipectomy, LipX) in lean mice, resulting in a compensatory 50% increase in total fat mass, is associated with significant improvement in glucose tolerance. This study was designed to further examine the link between fat removal, adipose tissue compensation and glucose homeostasis using a peroxisome proliferator-activated receptor γ (PPAR γ; activator of adipogenesis) knockout mouse. MATERIAL AND METHODS: The study involved PPARγ knockout (FKOγ) or control mice (CON), subdivided into groups that received LipX or Sham surgery. We reasoned that as the ability of adipose tissue to expand in response to LipX would be compromised in FKOγ mice, so would improvements in glucose homeostasis. RESULTS: In CON mice, LipX increased total adipose depot mass (~60%), adipocyte number (~45%) and changed adipocyte distribution to smaller cells. Glucose tolerance was improved (~30%) in LipX CON mice compared to Shams. In FKOγ mice, LipX did not result in any significant changes in adipose depot mass, adipocyte number or distribution. LipX FKOγ mice were also characterized by reduction of glucose tolerance (~30%) compared to shams. CONCLUSIONS: Inhibition of adipose tissue PPARγ prevented LipX-induced increases in adipocyte expansion and produced a glucose-intolerant phenotype. These data support the notion that adipose tissue expansion is critical to maintain and/or improvement in glucose homeostasis.

The role of visceral and subcutaneous adipose tissue fatty acid composition in liver pathophysiology associated with NAFLD.

Visceral adiposity is associated with type-2-diabetes, inflammation, dyslipidemia and non-alcoholic fatty liver disease (NAFLD), whereas subcutaneous adiposity is not. We hypothesized that the link between visceral adiposity and liver pathophysiology involves inherent or diet-derived differences between visceral and subcutaneous adipose tissue to store and mobilize saturated fatty acids. The goal of the present study was to characterize the fatty acid composition of adipose tissue triglyceride and portal vein fatty acids in relation to indices of liver dysregulation. For 8 weeks rats had free access to control (CON; 12.9% corn/safflower oil; 3.6 Kcal/g), high saturated fat (SAT; 45.2% cocoa butter; 4.5 Kcal/g) or high polyunsaturated fat (PUFA; 45.2% safflower oil; 4.5 Kcal/g) diets. Outcome measures included glucose tolerance, visceral and subcutaneous adipose tissue triglyceride, liver phospholipids and plasma (portal and systemic) free fatty acid composition, indices of inflammation and endoplasmic reticulum stress in the liver and adipose tissue depots and circulating adipo/cytokines. Hepatic triglycerides were significantly increased in both high fat diet groups compared to control and were significantly higher in PUFA compared to SAT. Although glucose tolerance was not different among diet groups, SAT increased markers of inflammation and ER stress in the liver and both adipose tissue depots. Fatty acid composition did not differ among adipose depots or portal blood in any dietary group. Overall, these data suggest that diets enriched in saturated fatty acids are associated with liver inflammation, ER stress and injury, but that any link between visceral adipose tissue and these liver indices does not involve selective changes to fatty acid composition in this depot or the portal vein.

Self-perception in elite collegiate female gymnasts, cross-country runners, and track-and-field athletes.

OBJECTIVE: To compare self-perception between a group of competitive, elite female collegiate athletes (participating in gymnastics, cross country, and track and field) and a group of female political science students (nonathletic control subjects). We hypothesized that the athletic group would rate athletics as more important than would the nonathletic group, that the perception of athletic competence would correlate positively with self-worth for athletes only, and that the perception of athletic competence would have a stronger influence on self-worth in the athletic group. SUBJECTS AND METHODS: The Self-perception Profile for College Students was completed by 32 athletes and 13 nonathletes. This profile measures 12 subscales plus Global Self-worth independently and generates scores that reflect the subject's perceived importance of and competence in each of the subscale areas. RESULTS: The athletes rated athletics as more important than did nonathletes, although this trend was nonsignificant when adjusted for age. As age increased, the importance of athletics decreased for both groups. There was a direct relationship between perceived athletic competence and self-worth for the athletes but not for the nonathletes. Variables that accounted for the Global Self-worth score in athletes were perceptions of Competence subscales for Appearance, Social Acceptance, Friendship, and Job. Variables that accounted for the Global Self-worth scores in the nonathletes were perceptions of Competence subscales for Romance, Morality, Humor, and Appearance. The athletic group had significantly lower Global Self-worth scores than the nonathletic group. CONCLUSIONS: The female athletes in this study derived a large component of their self-worth from their perceived athletic competence. Clinicians should bear in mind the relative importance of athletics to young female athletes and the relationship of perceived athletic ability to self-worth when treating these individuals.