A comparison of a personal series of biliopancreatic diversion and literature data on gastric bypass help to explain the mechanisms of resolution of type 2 diabetes by the two operations.

BACKGROUND: Roux-en-Y gastric bypass (RYGBP) and biliopancreatic diversion (BPD) are highly beneficial operations for type 2 diabetes mellitus (T2DM) in obese patients, leading to complete T2DM resolution in 75-90 and 97-99% of cases, respectively. In both RYGBP and BPD, the foregut is excluded from the food stream and the distal small bowel receives the food stimulation, while following BPD fat intestinal absorption is also extremely limited. This study was carried out to identify clinical features that could give insight on the different mechanisms of action on diabetes resolution. METHODS: The files of 443 severely obese patients with T2DM undergoing BPD from May 1976 to May 2007 were examined, and the presence of T2DM (fasting serum glucose >125 mg/ml) at 1-2 months, at 1 year, at 10 years, and at > or =20 years following the operation was recorded. RESULTS: The percentage of patients cured (fasting serum glucose reduced to < or =110 mg/dl, on free diet and with no therapy) was 74% at 1 month, 97% at 1 and 10 years, and 91% at > or =20 years, the 26% of uncured patients at 1 month being those with most severe preoperative T2DM. CONCLUSIONS: As the early results after BPD resemble those reported after RYGBP, it can be hypothesized that the duodenal exclusion and the distal small bowel stimulation are the first mechanisms acting in BPD, immediately after the operation, that only subsequently the myocellular fat depletion, which cannot be immediate, takes over, and that the minimal fat absorption is the mechanism accounting for the long-term results of BPD.

Relationships of serum leptin to clinical and anthropometric findings in obese patients.

BACKGROUND: The authors evaluated the relationship between leptin and the clinical, anthropometric and metabolic variables connected to the metabolic syndrome in obese individuals. METHODS: A large group of patients with different degrees of obesity was investigated: body mass index (BMI) values, serum leptin, fasting glucose and insulin, triglycerides and HDL-cholesterol concentrations, insulin resistance index and blood pressure were measured. RESULTS: On multiple regression analysis, serum leptin levels appeared to be positively correlated to the BMI and to the serum HDL-cholesterol concentration. Principal component factor analysis revealed three factors, explaining 61.3% of the total variance of the sample. General features of these factors were: factor 1--BMI values and serum leptin and fasting glucose concentration; factor 2--systolic and diastolic blood pressure and serum triglycerides and HDL-cholesterol concentration; factor 3--fasting serum insulin concentration and insulin resistance index. CONCLUSIONS: In obese subjects multiple factors underlie the metabolic syndrome and therefore more than one mechanism may account for the clustering characteristics. In obese patients leptin loads only one factor, and therefore leptin does not appear to be a key feature in the metabolic syndrome. On the contrary, multiple correlation and factor analysis data give rise to the hypothesis that in obese patients, leptin may play a protective role against cardiovascular risk.

Leptin and insulin action in severely obese women.

BACKGROUND: The authors investigated the interrelationships between the components of the metabolic syndrome in severe obesity. METHODS: In non-diabetic, severely obese women, the degree of obesity (BMI), the insulin sensitivity (from the Homeostatic Model of Assessment, HOMA), the serum leptin concentration and the presence of dyslipidemia and arterial hypertension were evaluated. RESULTS: In insulin-resistant patients, an overall impaired metabolic status and a greater cardiovascular risk were observed, while serum leptin concentration was higher than in the insulin-sensitive ones. Leptin levels and HOMA data correlated independent of BMI findings, while the presence of dyslipidemia and hypertension was unrelated to the other metabolic syndrome factors. CONCLUSION: In severely obese women, although other factors independently intervene, serum leptin has a role in developing the metabolic syndrome.