Effects of the Magenstrasse and Mill operation for obesity on plasma leptin and insulin resistance

Background: We evaluated the effect of the Magenstrasse and Mill (M & M) operation-a new form of non-banded vertical gastroplasty-on weight loss, plasma leptin levels and insulin resistance. Methods: Fasting plasma glucose, leptin and insulin levels were measured in 12 normal controls, 39 morbidly obese patients and 39 patients a median 3 years after the M & M procedure. Insulin resistance was calculated by the homeostasis model insulin resistance index. Results: Body mass index mean (s.d.) decreased significantly (p < 0.0001), from 48(7) to 33(5) kg/m(2), after the M & M procedure. Fasting plasma leptin concentration in the morbidly obese group was 37.9(15.4) ng/ml, significantly (p < 0.0001) higher than the control group (12.2(8.4)) and the M & M group (19.1(12.7)) ng/ml. Fasting plasma insulin concentrations were also significantly (p < 0.0001) higher in the morbidly obese group compared with than in the M & M group or in the control group: 35.5(22.3) mU/l, 15.5(7.1) mU/l and 13.6(3.4) mU/l, respectively. Insulin resistance was 9.6(7.2) in the morbidly obese group and 3.5(1.9) in the M & M group (p < 0.0001). Conclusion: This is one of the first studies to show that the decrease in insulin resistance after weight loss achieved by anti-obesity surgery is associated with significantly lower levels of plasma leptin.