Comment on Gastaldelli et al. Short-term Effects of Laparoscopic Adjustable Gastric Banding Versus Roux-en-Y Gastric Bypass. Diabetes Care 2016;39:1925–1931

We read with interest the article by Gastaldelli et al. (1), and we commend the authors on their findings. They studied obese patients without diabetes and demonstrated a difference in insulin sensitivity between the two surgical approaches. Specifically, they note an improvement in insulin sensitivity of adipose and muscle tissue in the Roux-en-Y group.

We would like to share with you that the authors’ findings corroborate our observations on the impact of the weight-loss surgeries on obesity and obesity-related metabolic and cardiovascular markers of disease (2–5). In our series, which included patients with diabetes and with insulin resistance, we found that weight-loss surgery led to correction of metabolic derangements that persisted up to 9 months after surgery (2). At 2 years, patients who underwent Roux-en-Y had lower leptin levels that correlated with weight loss, loss of fat mass, insulin levels, and insulin resistance (5). In the same study, adiponectin levels were also inversely correlated with insulin levels and insulin resistance in the Roux-en-Y group. In both surgical groups, the improvement in insulin sensitivity and correction of other metabolic derangements translated into improved cardiac function. We noted this in two other studies, which demonstrated dramatic changes in gene expression of fatty acid metabolism and progressive reversal of left ventricular mass and contractile dysfunction (2,4).

Put together with our observations, the article by Gastaldelli et al. (1) demonstrates the impact of rapid weight loss on metabolic markers of obesity, which is noted as early as 1 week and is more pronounced and sustained with Roux-en-Y. This difference, when compared with gastric banding, is likely a function of both the physiological and anatomical changes to the gastrointestinal tract innate in the Roux-en-Y technique. Nonetheless, meaningful weight loss over the long term by either surgical method or caloric restriction will correct metabolic derangements, albeit to varying degrees and at a different rate. This ultimately has important implications for metabolic and end-organ function involving adipose tissue, muscle, liver, pancreas, and the heart.