PPAR-γ Gene Expression in Human Adipose Tissue Is Associated with Weight Loss After Sleeve Gastrectomy

Abstract

Background: The peroxisome proliferator-activated receptor (PPAR)-γ plays a key role in adipose tissue differentiation and fat metabolism. However, it is unclear which factors may regulate its expression and whether obese patients have changes in adipose tissue expression of PPAR-γor potential regulators such as miR-27. Thus, our aims were to analyze PPAR-γ and miR-27 expression in adipose tissue of obese patients, and to correlate their levels with clinical variables.

Subjects and methods: We included 43 morbidly obese subjects who underwent sleeve gastrectomy (31 of them completed 1-year follow-up) and 19 non-obese subjects. mRNA expression of PPAR-γ1 and PPAR-γ2, miR-27a, and miR-27b was measured by qPCR in visceral and subcutaneous adipose tissue. Clinical variables and serum adipokine and hormone levels were correlated with PPAR-γ and miR-27 expression. In addition, a systematic review of the literature regarding PPAR-γ expression in adipose tissue of obese patients was performed.

Results: We found no differences in the expression of PPAR-γ and miR-27 in adipose tissue of obese patients vs. controls. The literature review revealed discrepant results regarding PPAR-γ expression in adipose tissue of obese patients. Of note, we described a significant negative correlation between pre-operative PPAR-γ1 expression in adipose tissue of obese patients and post-operative weight loss, potentially linked with insulin resistance markers.

Conclusion: PPAR-γ1 expression in adipose tissue is associated with weight loss after sleeve gastrectomy and may be used as a biomarker for response to surgery.

Keywords: Bariatric surgery; Obesity; PPAR gamma; miR-27.

Fig. 1

Relative mRNA expression in adipose tissue of obese patients and controls. A) PPAR-γ1 and PPAR-γ2 mRNA expression in visceral and subcutaneous adipose tissue in non-obese (n = 19) and obese (n = 43) subjects. B) PPAR-γ1 mRNA expression in non-obese women (n = 11) and obese women (n = 34). Results are expressed as a fold-change relative to the control group (AU: arbitrary unit; mean ± SEM; * P < 0.05)

Fig. 2

Relative microRNA expression in adipose tissue of obese patients and controls. miR-27a-3p and miR-27a-3p microRNA expression in visceral and subcutaneous adipose tissue in non-obese (n = 19) and obese (n = 43) subjects. Results are expressed as a fold-change relative to the control group (AU: arbitrary unit; mean ± SEM)

Fig. 3

Relationship between baseline mRNA expression of PPAR-γ1 and weight loss after surgery. A) Correlation of mRNA expression in visceral adipose tissue and percentage of weight loss (ρ =  − 0.460; P = 0.009). B) Correlation of mRNA expression in subcutaneous adipose tissue and percentage of weight loss in subcutaneous adipose tissue (ρ =  − 0.404; P = 0.024). C) Relative mRNA expression of PPAR-γ1 in visceral and subcutaneous adipose tissue in patients who lost less than 33% of bodyweight (n = 15) and patients who lost more than 33% of bodyweight (n = 16). Results are expressed relative to values of the control group (AU: arbitrary unit; mean ± SEM; * P < 0.05)