Obesity-related differential gene expression in the visceral adipose tissue

Background: This study investigates the expression patterns in human adipose tissue, and identifies genes that may be involved in the abnormal energy homeostasis. Methods: Subjects were prospectively recruited from morbidly obese patients undergoing bariatric surgery and from non-obese organ donors. Extensive clinical data and visceral fat specimens were obtained from each subject at the time of surgery. A group of 50 obese patients and 9 non-obese controls were selected for further study. Two custom two-color cDNA microarrays were produced with 40,173 human individual cDNA clones. Microarray experiments were performed for each sample, and a selected group of gene expression values were confirmed with real-time RT-PCR. Results: A comparison of gene expression profiles from obese and non-obese patients identified 1,208 genes with statistically significant differential expression between the 2 groups. Most prominent among these genes are multiple glycolysis enzyme encoding genes; others are involved in oxysterol biosynthesis and signaling, or are ATP-binding transporters and solute carriers. Conclusion: Differential gene expression in the adipose tissue of morbidly obese patients includes genes related to lipid and glucose metabolism, membrane transport, and genes promoting the cell cycle. These findings are a first step toward clarifying the molecular pathogenesis of obesity and identifying potential targets for therapeutic intervention.