Objective
To determine the frequency of Melanocortin4 Receptor (MC4R) mutations in morbidly obese adolescents undergoing bariatric surgery and compare weight loss outcomes in patients with and without mutations.
Design and Methods
In this prospective cohort study, 135 adolescent patients evaluated for bariatric surgery were screened for MC4R mutations; 56 had 12 month postoperative data available for analysis.
Results
MC4R mutations were detected in five of the 135 patients (3.7%); four underwent restrictive bariatric surgery. For the three patients with gastric banding, percent excess weight loss (%EWL) postoperatively was 36.0% at 5 years in one, 47% at 4 years in the second, and 85% at 1 year in the third. For the patient with gastric sleeve resection, %EWL of 96% was attained at 1 year postoperatively. The four MC4R cases had a higher, although non-significant, %EWL compared to 52 non-matched controls at 12 months postoperatively (48.6% vs. 23.4%; p<0.37). When matched by age, sex, and race to 14 controls, there was no significant difference in %EWL (p < 0.31), BMI change (p< 0.27), or absolute weight loss (p <0.20).
Conclusion
The frequency of MC4R mutations is similar to prior studies, with affected patients showing beneficial weight loss outcomes.
Objective
Obese individuals have high levels of circulating leptin and are resistant to the weight-reducing effect of leptin administration at physiological doses. Although Roux-en-Y gastric bypass (RYGB) is an effective weight loss procedure, there is a plateau in weight loss and most individuals remain obese. This plateau may be partly due to the decline in leptin resulting in a state of relative leptin insufficiency. The main objective of this study was to determine whether leptin administration to post-RYGB patients would promote further weight reduction.
Design and Methods
This was a randomized, double-blind, placebo-controlled cross-over study of 27 women who were at least 18 months post-RYGB and lost on average 30.8% of their pre-surgical body weight. Subjects received either leptin or placebo via subcutaneous injection twice daily for 16 weeks, then crossed over to receive the alternate treatment for 16 weeks.
Results
Weight change after 16 weeks of placebo was not significantly different from that after 16 weeks of leptin. No changes were observed in percent fat mass, resting energy expenditure, thyroid hormones, or cortisol levels.
Conclusions
Contrary to our hypothesis, we did not observe a significant effect of leptin treatment on body weight in women with relative hypoleptinemia after RYGB.
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