Expression of genes related to energy metabolism (osteocalcin, FOXO1, insulin receptor, and SOST) in bone cells of Goto-Kakizaki rats and response to bariatric surgery.

Objectives: The aim of this experimental study was to evaluate the expression of 4 genes (osteocalcin, sclerostin (SOST), insulin receptor, and transcription factor forkhead box protein (FOXO1) in the bone cells of Goto-Kakizaki (GK) rats and the expression of these genes in response to bariatric surgery. Methods: We designed an experimental study with 3 arms (Wistar rats, nonoperated GK rats, and GK rats with gastrojejunal bypass). Gene expression (osteocalcin, insulin receptor, FOXO1, SOST) was measured at baseline and after surgery. Plasma levels of glucose, insulin, homeostasis model assessment (HOMA), glucagon-like peptide 1 (GLP-1), and the production of insulin were measured at baseline and at 60 minutes by pancreatic islets. Results: GK rats had decreased levels of expression of osteocalcin (50.86 +/- 19.21 versus 16.78 +/- 22.11, P = .031), insulin receptor (1.45 +/-.44 versus .54 +/-.35, P = .020), and SOST (.92 +/-.05 versus .43 +/-.47, P = .048) compared with Wistar rats. Gene expression in GK rats, operated and nonoperated, was similar. In nonoperated GK rats, there was a negative correlation between the SOST gene and plasma insulin (r: -.786, P = .021) and the production of insulin by pancreatic islets at 60 minutes (r: -0.857, P = .014). GLP-1 increased after surgery. Conclusion: Diabetic GK rats presented a reduced expression of the osteocalcin, insulin receptor, and SOST genes. There was an inverse relationship between SOST and plasma and local insulin. We found no changes in the expression of bone genes that regulate energy metabolism after gastrojejunal bypass. (C) 2014 Published by Elsevier Inc. on behalf of American Society for Metabolic and Bariatric Surgery.