TCF7L2 expression in diabetic patients undergoing bariatric surgery A. Katharine Hindle Æ Fred Brody Æ Rahul Tevar Æ Brian Kluk Æ Sarah Hill Æ Timothy McCaffrey Æ Sidney Fu Received: 21 September 2007 / Accepted: 3 May 2008 / Published online: 21 September 2008 Ó Springer Science+Business Media, LLC 2008 Abstract Introduction The cause of diabetes in morbidly obese patients is multifactorial, including genetic, social, and die- tary components. Transcription factor 7-like 2 (TCF7L2) is a gene that is related to the development of diabetes. This pilot study examines TCF7L2 expression in liver samples obtained from morbidly obese patients undergoing bariatric surgery. TCF7L2 expression is compared between diabetic and nondiabetic patients. Methods Liver samples were obtained from 20 morbidly obese patients undergoing bariatric surgery. Samples were flash frozen in liquid nitrogen. Total RNA was extracted from tissue samples using the TRIzol reagent (Invitrogen Inc, Carlsbad, CA). Using the iScript cDNA synthesis kit (Bio-Rad Laboratories, Hercules,CA), cDNA was synthe- sized. Quantitative polymerase chain reaction (qPCR) was done using SYBR Green qPCR Reagents (Stratagene, Cedar Creek TX) and the 7300 Real-Time PCR system (Applied Biosystems, Foster City CA). Preoperative demographic and gene expression data were correlated using univariate analysis and logistic regression models. Only associations with a p-value less than 0.05 were con- sidered significant. Results For the entire group, there was no correlation between body mass index (BMI) and TCF7L2 expression. In morbidly obese nondiabetic patients, there was a posi- tive correlation between TCF7L2 expression and BMI (R 2 = 0.21). In morbidly obese diabetic patients, there was an inverse correlation between TCF7L2 expression and BMI (R 2 = 0.58). There was no significant relationship between TCF7L2 expression and age or glycosylated hemoglobin (HbA1c). Conclusions The cause of diabetes is multifactorial but the data from our pilot study documents the relationship of TCF7L2 with type 2 diabetes in morbidly obese patients. Keywords Bariatric Á Obesity Several series document that bariatric surgery resolves type 2 diabetes [1, 2]. However, the mechanisms behind these changes are unclear. The dramatic changes in insulin resis- tance and/or secretion following weight-loss surgery may produce corresponding changes in the expression patterns of individual genes or sets of related or co-regulated genes. By identifying these genes, the pathophysiology of type 2 diabetes may be discerned. Clearly, obesity and its comor- bidities are related genetically in a variety of distinct pathways. Previous reports illustrate that obesity correlates with a decrease in the expression of peroxisome proliferators activated receptor gamma (PPARc) which causes adipocyte maturation and differentiation [3]. Moreover, recent data A. K. Hindle Á R. Tevar Department of Surgery, The George Washington University Medical Center, Washington, DC, USA F. Brody (&) Á S. Hill Department of General Surgery, The George Washington University Medical Center, Washington, DC, USA e-mail: fbrody@mfa.gwu.edu B. Kluk Á T. McCaffrey Á S. Fu Department of Biochemistry and Molecular Biology, The George Washington University Medical Center, Washington, DC, USA 123 Surg Endosc (2009) 23:700–704 DOI 10.1007/s00464-008-0001-2