Roux-en-Y Gastric Bypass Modulates Gene Expression in Hypothalamus and Heart

Strategic Insights -

Researchers have discovered that Roux-en-Y gastric bypass surgery (RYGB) regulates the expressions of microRNA-122 (miR-122) in the hypothalamus, heart, and liver, which may modulate the activities of adenosine monophosphate-activated protein kinase (AMPK), the master regulator of metabolism. The study, conducted at Keimyung University in Daegu, South Korea, used microarray analyses to identify changes in gene expression in the brains and hearts of rats after RYGB surgery. The results suggest that RYGB stimulates the expression of miR-122 in the hypothalamus, while inhibiting its expression in the heart and liver. This may lead to changes in AMPK activity, which plays a crucial role in regulating metabolism.

Key Takeaways:

  • RYGB surgery regulates the expressions of miR-122 in the hypothalamus, heart, and liver, which may modulate the activities of AMPK.
  • Microarray analyses revealed that miR-122 was predominantly found in the liver, and its expression increased 35-fold in the hypothalamus and decreased 4-fold in the heart following RYGB surgery.
  • Quantitative polymerase chain reaction analysis confirmed that the expression of miR-122 was induced in the hypothalamus but attenuated in the heart and liver of rats after RYGB surgery.
  • The activities of AMPK were decreased in the hypothalamus but increased in the heart and liver following RYGB surgery.
  • Knockdown of miR-122 in hepatocellular carcinoma cells stimulated phosphorylation levels of AMPK, indicating that miR-122 may play a role in regulating AMPK activity.
  • The study suggests that RYGB may be a potential therapeutic strategy for modulating gene expression and metabolism in connection with various diseases, including cancer and metabolic disorders.
  • The researchers collected blood samples from 20 healthy individuals and 20 individuals with obesity and/or type 2 diabetes and used them to validate the results of their animal study.

Statistics:

  • The study observed changes in food intake and body weight in rats after RYGB surgery, with body weights decreasing in the RYGB group compared to those in the sham group.
  • The researchers identified 350 miRNAs that were investigated, and miR-122 was found to be predominantly expressed in the liver.
  • The expression of miR-122 increased 35-fold in the hypothalamus and decreased 4-fold in the heart following RYGB surgery.
  • Quantitative polymerase chain reaction analysis revealed that the expression of miR-122 was induced in the hypothalamus (2.5-fold) but attenuated in the heart (-2.5-fold) and liver (-2-fold) of rats after RYGB surgery.
  • The activities of AMPK were decreased in the hypothalamus (2.5-fold) but increased in the heart (2.5-fold) and liver (2-fold) following RYGB surgery.

Sources:

  • Roux-en-Y gastric bypass stimulates hypothalamic miR-122 and inhibits cardiac and hepatic miR-122 expressions. Journal of Surgical Research, 2015;199(2):371-377.
  • Academic Press Inc Elsevier Science, 525 B St, Ste 1900, San Diego, CA 92101-4495, USA.