Bariatric surgery acutely changes the expression of inflammatory and lipogenic genes in obese adipose tissue

Background: Adipose tissue of obese subjects is known to exhibit increased inflammatory activity linked to altered expression of factors involved in glucose and lipid metabolism. The surgical procedure constitutes an injury per se, evoking a systemic inflammatory response.

Objective: To evaluate changes in the expression of key-genes in adipose tissue after common surgical procedures performed in obese patients.

Setting: A tertiary hospital.

Methods: Paired subcutaneous (SAT) and visceral (VAT) adipose tissue samples were collected at the beginning and the end of surgery in 33 obese patients that underwent laparoscopic Roux-en-Y gastric bypass (RYGB, n = 17) or laparoscopic vertical sleeve gastrectomy (SG, n = 16). The expression of genes involved in inflammation, glucose and lipid metabolism was assessed.

Results: The surgical procedure led to increased expression of interleukin 6, interleukin 8 (P<.0001 in both depots), tumor necrosis factor α (P = .001 in SAT), and lipopolysaccharide binding protein (P = .0004 in VAT). Surgery also induced concomitant decreased expression of GLUT4, IRS1 (P = .046 in VAT), and adiponectin, whereas the messenger RNA of lipogenic genes [fatty acid synthase (P = .024); sterol regulatory element binding transcription factor 1 (P = .011) and aquaporin 9 (P<.0001) in SAT; and PPARγ (P = .018) and solute carrier family 27 (fatty acid transporter), member 2 (P = .028) in VAT] increased in parallel to inflammation. Changes in gene expression during surgery were enhanced in patients following RYGB, when compared with SG.

Conclusions: Bariatric surgery acutely changes the expression of inflammatory and lipogenic genes in adipose tissue. This information should be considered cautiously when designing studies to assess adipose tissue gene expression in morbidly obese patients. The same timing of sampling is mandatory.