BioProject

Gallstone disease is a major contributor to health care costs in the United States. More...

Gallstone disease is a major contributor to health care costs in the United States. Approximately 12 % of the U.S. population has gallstones. As a result, more than 700,000 cholecystectomies are performed in this country each year. Many of these patients are obese and have a positive family history; but surprisingly, little is known about the link between obesity, genetics and gallstone formation. Obese individuals have been shown to have supersaturated bile, larger gallbladder fasting volumes and impaired gallbladder emptying. We have recently demonstrated that leptin plays a role in gallbladder motility. In an effort to understand the genetic basis for these observations, we tested the hypothesis that leptin would alter gallbladder gene expression. Methods: Affymetrix oligonucleotide microarrays 430 2.0 were used to compare gallbladder gene expression profiles from 12 week old control saline-treated leptin-deficient (Lep ob) and from leptin-treated Lep ob female mice. Analyses were performed on pooled RNA (n=4) from the gallbladders of 12 saline-treated Lep ob mice and from 12 Lep ob mice which were administered daily IP 5 ug/g of recombinant murine leptin for 4 weeks. Resulting data were analyzed utilizing Gene Chip Operating Software or MAS 5.0. Results: Of the genes analyzed 314 were upregulated and 108 were downregulated by leptin administration. Numerous genes related to gallstone pathogenesis, gallbladder absorption/secretion, inflammatory cytokines, and insulin resistance were altered by leptin. Keywords: comparitive response to leptin Overall design: Female B6.V-lepob obese mice (n=24) aged 7 weeks were obtained from The Jackson Laboratory (Bar Harbor, ME). Upon arrival, mice were placed on a standard chow diet and were allowed to acclimate for 1 week before starting the experiment. For leptin treatments, mice received daily intraperitoneal injections of either recombinant mouse leptin (R&D Systems, Minneapolis, MN) (n=12) at a dose of 5 µg/g body weight or with saline as a control (n=12) for 4 weeks. At 12 weeks of age, mice were fasted overnight with free access to water. The following morning the mice underwent cholecystectomy. Three gallbladders were pooled to create 4 pools in each treatment and total RNA was isolated. Affymetrix murine 430 2.0 arrays were utilized to examine altered gallbladder gene expression as a result of leptin administration. The resulting data was analyzed utlizing Gene Chip Operating Software or MAS 5.0. Less...