Biological Sample Repository for Gastrointestinal Disorders

The prevalence of obesity in the U.S. has reached unacceptably high numbers over the past three decades. Approximately 68% of the American population over the age of 20 is overweight, while 35.7% meet criteria for obesity (CDC). Obesity has become a leading cause of morbidity, mortality and reduced quality of life; and places patients at high risk for several chronic conditions, including: diabetes (DM), hypertension (HTN), hyperlipidemia (HL), sleep apnea, GERD, musculoskeletal disorders and cancer. In addition, obesity imposes a major burden in the American healthcare system, with an estimated annual cost of 147 billion U.S. dollars.

Treatment of obesity is challenging. Preventive measures and medical therapy have not been effective in fighting this epidemic. Diet and exercise, though logical, are hindered by high recidivism and a propensity to regain weight to pre-weight loss levels. Anti-obesity drugs are largely ineffective and limited by safety and side-effects profile. Even bariatric surgery, which provides significant and rapid weight loss, is still followed by substantial weight regain over time. In addition, surgery is associated with a 1% mortality risk, 5-25% 1-year morbidity, and is not readily accessible. Fewer than 1% of eligible obese patients undergo surgery each year. In face of all these challenges, there is an urgent need to better understand the pathophysiology of obesity and the effects of current weight loss interventions. This knowledge will provide a new framework for the development of more effective preventive measures and therapies.

The pathophysiology of obesity is complex. Weight gain results from an energy imbalance; that is, when energy intake is higher than expenditure. In this context, obesity has been attributed to a shift in diet toward increased consumption of energy-dense foods, and to sedentary lifestyle. However, little is known about the physiological mechanisms underlying this trend, which are thought to be regulated by genetic, metabolic and neurobehavioral factors. Even less is understood on how increased adiposity leads to the development of many metabolic disorders, including DM. Surprisingly, these mechanisms can be reversed by bariatric procedures, which in addition to weight loss, have dramatic beneficial effects on metabolic disorders such as DM, HTN, and HL. Therefore, surgery has become an important study tool to enhance our understanding of the pathophysiology of obesity. The collection of biological samples from patients before and after weight loss therapies, including endoscopic and surgical procedures, will provide the basis for a series of studies that will focus on investigating:

• the mechanisms that lead to obesity, particularly appetite and gut regulatory peptides;
• the clinical, physiological, hormonal and metabolic changes imposed by medical, surgical and endoscopic procedures to treat obesity;
• the mechanisms of weight regain following bariatric surgery;
• the mechanism of failure to lose weight following endoscopic or surgical procedures;
• the effects of endoscopic procedures on weight regain following bariatric surgery;
• biomarkers that predict response to medical, endoscopic and surgical therapies;
• biomarkers that predict weight regain or therapeutic failures;
• novel therapeutic targets for the treatment of obesity.

Medical therapies include weight loss diets or anti-obesity medications. Bariatric endoscopic procedures include ablation techniques, intragastric balloons, submucosal tunneling procedures (PSAM, GEM, G-POEM), tissue plication platforms (POSE, ROSE), endoluminal sleeves and endoscopic suturing devices (ESG).