ABSTRACT: Transcription profiling of human skeletal muscle from morbidly obese patients before and after gastric bypass surgery to identify genes responsive to weight loss.
Project description:Obesity results from a chronic imbalance between energy intake and energy expenditure, with excess calories stored as fat. As such, weight loss has long been considered as a primary goal of treatment for obesity. A surgical treatment of severe obesity such as gastric bypass provides the most dramatic reductions in body weight, and a well-known effect of weight loss is an improvement in insulin sensitivity. However, the molecular mechanism underlying this association remains unclear. Thus, we profiled skeletal muscle of morbidly obese patients before and after gastric bypass surgery. Results from this project will provide global patterns of gene expression with weight loss, which help to understand the pathogenesis of obesity at the molecular level. Experiment Overall Design: To identify responsive genes to weight loss.
Project description:Obesity results from a chronic imbalance between energy intake and energy expenditure, with excess calories stored as fat. As such, weight loss has long been considered as a primary goal of treatment for obesity. A surgical treatment of severe obesity such as gastric bypass provides the most dramatic reductions in body weight, and a well-known effect of weight loss is an improvement in insulin sensitivity. However, the molecular mechanism underlying this association remains unclear. Thus, we profiled skeletal muscle of morbidly obese patients before and after gastric bypass surgery. Results from this project will provide global patterns of gene expression with weight loss, which help to understand the pathogenesis of obesity at the molecular level. Keywords: Time-Series
Project description:The mechanisms of weight loss and metabolic improvements following bariatric surgery in skeletal muscle are not well known, however epigenetic modifications are likely to contribute. The aim of our study was to investigate skeletal muscle DNA methylation after weight loss induced by Roux-en-Y gastric bypass (RYGB) surgery.
Project description:miRNA profiles were investigated in skeletal muscle in severely obese individuals with or without diabetes before and after Roux-en-Y gastric bypass surgery.
Project description:The mechanisms underlying improved insulin sensitivity after surgically-induced weight loss are still unclear. We monitored skeletal muscle metabolism in obese individuals before and over 52 weeks after metabolic surgery. Initial weight loss occurs in parallel with a decrease in muscle oxidative capacity and respiratory control ratio. Persistent elevation of intramyocellular lipid intermediates, likely resulting from unrestrained adipose tissue lipolysis, accompanies the lack of rapid changes in insulin sensitivity. Simultaneously, alterations in skeletal muscle expression of genes involved in calcium/lipid metabolism and mitochondrial function associate with subsequent distinct DNA methylation patterns at 52 weeks after surgery. Thus, initial unfavorable metabolic changes including insulin resistance of adipose tissue and skeletal muscle precede epigenetic modifications of genes involved in muscle energy metabolism and the long-term improvement of insulin sensitivity.
Project description:The mechanisms underlying improved insulin sensitivity after surgically-induced weight loss are still unclear. We monitored skeletal muscle metabolism in obese individuals before and over 52 weeks after metabolic surgery. Initial weight loss occurs in parallel with a decrease in muscle oxidative capacity and respiratory control ratio. Persistent elevation of intramyocellular lipid intermediates, likely resulting from unrestrained adipose tissue lipolysis, accompanies the lack of rapid changes in insulin sensitivity. Simultaneously, alterations in skeletal muscle expression of genes involved in calcium/lipid metabolism and mitochondrial function associate with subsequent distinct DNA methylation patterns at 52 weeks after surgery. Thus, initial unfavorable metabolic changes including insulin resistance of adipose tissue and skeletal muscle precede epigenetic modifications of genes involved in muscle energy metabolism and the long-term improvement of insulin sensitivity.
Project description:The mechanisms underlying improved insulin sensitivity after surgically-induced weight loss are still unclear. We monitored skeletal muscle metabolism in obese individuals before and over 52 weeks after metabolic surgery. Initial weight loss occurs in parallel with a decrease in muscle oxidative capacity and respiratory control ratio. Persistent elevation of intramyocellular lipid intermediates, likely resulting from unrestrained adipose tissue lipolysis, accompanies the lack of rapid changes in insulin sensitivity. Simultaneously, alterations in skeletal muscle expression of genes involved in calcium/lipid metabolism and mitochondrial function associate with subsequent distinct DNA methylation patterns at 52 weeks after surgery. Thus, initial unfavorable metabolic changes including insulin resistance of adipose tissue and skeletal muscle precede epigenetic modifications of genes involved in muscle energy metabolism and the long-term improvement of insulin sensitivity.
Project description:The mechanisms underlying improved insulin sensitivity after surgically-induced weight loss are still unclear. We monitored skeletal muscle metabolism in obese individuals before and over 52 weeks after metabolic surgery. Initial weight loss occurs in parallel with a decrease in muscle oxidative capacity and respiratory control ratio. Persistent elevation of intramyocellular lipid intermediates, likely resulting from unrestrained adipose tissue lipolysis, accompanies the lack of rapid changes in insulin sensitivity. Simultaneously, alterations in skeletal muscle expression of genes involved in calcium/lipid metabolism and mitochondrial function associate with subsequent distinct DNA methylation patterns at 52 weeks after surgery. Thus, initial unfavorable metabolic changes including insulin resistance of adipose tissue and skeletal muscle precede epigenetic modifications of genes involved in muscle energy metabolism and the long-term improvement of insulin sensitivity.
Project description:Roux-en-Y gastric bypass (RYGB) is the most effective therapy for morbid obesity, but it has a ~20% failure rate. We used our established RYGB model in diet-induced obese (DIO) Sprague-Dawley rats, which reproduces human bi-phasic body weight (BW) loss pattern, to determine mechanisms contributing to success (RGYB-S) or failed (RYGB-F) RYGB. DIO rats were randomized to RYGB, sham operated Obese, and sham operated obese pair fed-linked to RYGB (PF) groups. BW, caloric intake (CI) and fecal output (FO) were recorded daily for 90 days, food efficiency (FE) was calculated, and morphologic changes were determined. Gut, adipose and thyroid hormones were measured in plasma. Mitochondrial respiratory complexes in skeletal muscle, expression of energy-related hypothalamic and fat peptides, receptors and enzymes were quantified. A 25% failure rate occurred. RYGB-S, RYGB-F and PF rats vs. Obese showed rapid BW decrease, followed by sustained BW loss in RYGB-S. RYGB-F and PF gradually increased BW. Expression profiling of both CNS (hypothalamus) and peripheral tissues (subcutaneous abdominal fat) strongly supported the involvement of a number of metabolic and feeding-related genes in the differential outcomes. Experiment Overall Design: 3 biological replicate RNA samples were prepared from 2 tissues (the subcutaneous abdominal fat or the hypothalamus) from rats in 3 treatment groups (rats losing weight successfully after gastric bypass surgery, rats gaining weight, and rats that were fed the same amount as the treated rats)
Project description:Low-grade chronic inflammation plays an important role in the development of obesity and obesity-associated disorders such as insulin resistance, type 2 diabetes, the metabolic syndrome and atherosclerosis. One possible link between obesity and inflammation is the enhanced activation of circulating monocytes making them more prone to infiltration into the adipose and vascular tissues of obese persons. Furthermore, weight loss after bariatric surgery is associated with less inflammation. Transcriptome analysis of circulating monocytes from control and obese patients before and after bariatric surgery will potentially provide insights into the pathophysiology of obesity and associated disorders and supply biomarkers for diagnostic purpose. The cohort comprised 6 lean age-matched controls (BMI: 20.3±0.5 kg/m2, mean±SEM) and 18 obese individuals without clinical symptoms of cardiovascular disease (BMI: 45.1±1.4 kg/m2, P<0.001 compared with lean controls). These 18 morbidly obese subjects were referred to our hospital for bariatric surgery. Before they were included, individuals were evaluated by an endocrinologist, an abdominal surgeon, a psychologist and a dietician. Only after multidisciplinary deliberation, the selected patients received a laparoscopic Roux-en-Y gastric bypass. CD14+ monocytes were collected before and three months after bariatric surgery (BMI: 37.5±1.3 kg/m2, P<0.001 compared with before weight loss), total RNA was extracted and subjected to genome-wide expression analysis. Samples consisted of CD14+ monocytes from 6 lean controls and 18 morbidly obese patients before and three months after bariatric surgery. The 6 lean controls were also used to make 6 control pools.