Massive weight loss does not restore normal insulin secretory pulses in obese patients with type 2 (non-insulin-dependent) diabetes mellitus.

To study the effects of massive weight loss on insulin secretion, we analysed the oscillations of fasting peripheral insulin levels in obese patients who underwent vertical banded gastroplasty as treatment for morbid obesity. Patients were studied before and 6 months after surgery. Serial measurements of plasma free insulin levels were obtained in duplicates from 0 to 60 min at one-minute intervals. Insulin levels were then analysed by autocorrelation and Fourier transformation. In normal controls and obese patients, the first oscillatory insulin component was detected between 10 and 14 min. Compared to obese controls (n = 4), overt Type 2 diabetic patients (n = 4) had reduced amplitudes of insulin pulses and no oscillatory component. These defects were not as pronounced in patients with impaired glucose tolerance (IGT) after an oral glucose tolerance test (OGTT) (n = 5). When detected, the periodicity of the oscillations occurred at different periods. In 3/5 IGT patients, the first positive peak of correlation was found at 13.3 +/- 2.3 min. Weight loss (mean +/- SD) after 6 months was 24.3 +/- 3.7 for subjects with normal glucose tolerance (NGT), 37.9 +/- 9 for those with IGT and 29.8 +/- 5 kgs for Type 2 diabetic subjects. After weight loss, insulin oscillatory activity was detected in 4/5 IGT patients, with a period of 13 +/- 3 min. Weight loss did not reverse the defects observed in obese diabetic patients despite a significant reduction in peripheral insulin levels from 28.6 +/- 6 to 15.6 +/- 6 mU/l (p < 0.05). Insulin values remained higher than in obese controls (7.82 +/- 2, p < 0.05), and Type 2 patients remained mildly hyperglycaemic. These findings indicate that beta-cell activity is abnormal in Type 2 diabetic patients. The absence of modification after weight loss suggests that inherent beta-cell defects may contribute to hyperglycaemia.

[Treatment of severe obesity by calibrated vertical gastroplasty. 55 cases]. / Traitement de l'obésité sévère par gastroplastie verticale calibrée. 55 observations.

OBJECTIVES: Evaluate short-term outcome of calibrated vertical gastroplasty in obese subjects. METHODS: Calibrated vertical gastroplasty was performed in 55 obese subjects (BMI 43 +/- 1; age range 20-59 year). There were no post-operative complications. All the subjects were followed for 6 months and thirty one for a year. RESULTS: Weight loss reached 28 kg at 6 months and 36 kg at 1 year with an improvement in functional manifestations, especially for dyspnoea and, in half of the subjects, for signs of depression. New or worsened psychiatric problems were observed in 4 subjects. Post-prandial vomiting persisted for 1 year in 28 patients. Dietary intake was lowered (946 +/- 61 kcal/day) as was protein intake (43 +/- 3 g/24 hr). Impaired glucose tolerance, raised serum insulin, triglyceride and androgen levels were corrected in patients with abnormal levels before surgery. Serum vitamin B1 declined. CONCLUSION: These favourable results in the weight curve, functional problems and metabolic data should not mask the disadvantages and potential risks involved. Long-term prospective studies are required to determine the precise indications for this technique.