Definition and Use
The obesity epidemic represents an emerging public health crisis, because obesity promotes the development of various diseases, such as cardiovascular disease and diabetes, that greatly increase mortality. Although body weight reduction improves metabolic status and decreases the risk of co-morbidities, weight control is difficult for most patients. Currently, the most effective long-term weight-loss treatment is bariatric (weight-loss) surgery.
Types of Bariatric Procedures
Bariatric surgical procedures are traditionally characterized by the primary mechanism of weight-loss, namely intestinal malabsorption or gastric restriction. There are procedures that combine gastric restriction and malabsorption, such as Roux-en-Y gastric bypass (RYGB), and there are purely restrictive maneuvers, such as gastric banding. Combined procedures promote superior and longer lasting weight-loss and elimination of co-morbidities compared to purely restrictive maneuvers.
Roux-en-Y Gastric Bypass (RYGB)
RYGB emerged as a gold standard of bariatric surgery, because it surpasses purely restrictive procedures by promoting greater and longer-lasting weight-loss and elimination of obesity complications. Although gastric restriction and intestinal malabsorption are obvious mechanisms of weight loss after RYGB, it is increasingly recognized that hormonal changes may also play a major role. Multiple studies suggest that RYGB lowers levels of ghrelin, the appetite-stimulant enteric hormone which is mainly secreted by the gastric fundus. Chronic blockade of ghrelin decreases body weight in adult animals, thus it is plausible that decreased ghrelin levels contribute to patients eating fewer and smaller meals after RYGB. Furthermore, RYGB has been reported to increase the levels of appetite-suppressant hindgut hormones, such as peptide YY (PYY) and glucagon-like peptide-1 (GLP-1), which may also contribute to decreased food intake. Besides its effects on weight-loss and appetite, RYGB also dramatically reduces type 2 diabetes. RYGB patients exhibit increased levels of the insulin sensitizing adipocyte peptide adiponectin, which may contribute to the amelioration of insulin resistance.
Thus, it appears that RYGB became the bariatric procedure of choice, because its restrictive and malabsorptive effects are supported by complex endocrine changes to promote effective and long-term weight loss and elimination of co-morbidities. However, RYGB is an invasive procedure with multiple anastomoses which makes it less suitable for high-risk patients. For example, super-obese patients (Body Mass Index - BMI > 60kg/m2), who would benefit the most from RYGB procedure, represent the greatest perioperative risk which often limits their surgical treatment options. Given that the accelerating obesity epidemic continues to elevate the number of super-obese patients, it is increasingly important to identify safe bariatric surgical procedures for this high-risk patient population that effectively promote long-term weight-loss and elimination of co-morbidities.
Recently, sleeve gastrectomy emerged as a novel weight-loss surgical procedure, which seems to hold the potential of becoming an effective alternative stand alone procedure for weight control in high-risk super-obese patients.
Bariatric surgery in rats
The Integrative Core Laboratory investigators are in the process of adapting the human sleeve gastrectomy procedure to rats. This project is led by Dr. Peter Lopez, a young academic surgeon who recently joined the Integrative Core Laboratory team. Please, check back later for details.