Influence of meal ingestion on insulin profiles following intraperitoneal delivery.

This study evaluated the effect of meal ingestion on intraperitoneal insulin absorption in type I diabetic patients with an implanted pump for long-term intraperitoneal insulin delivery. On four separate occasions, patients (n = 7) were administered 15 IU insulin as a 20-minute square-wave infusion using their implanted device; hypoglycemia was prevented by intravenous infusion of 10% dextrose at a variable rate. Two studies were performed during fasting conditions (n = 2 fasting tests) and two studies after the administration of an 800-kcal standard meal (n = 2 postprandial tests). An insulin peak of 630 +/- 545.4 pmol/L (mean +/- SD) in fasting tests and 696 +/- 420.5 pmol/L in postprandial tests was reached in the peripheral circulation after 45 +/- 11.7 and 45 +/- 14.7 minutes, respectively, with no significant difference between the two experimental conditions. Areas under the insulin curves were not significantly different in fasting and postprandial tests (51,500 +/- 34,278 v 50,916 +/- 20,558 pmol/L.min-1, respectively; NS). In type I diabetic patients receiving long-term intraperitoneal insulin therapy, the increase in splanchnic blood flow following ingestion of a standard meal does not accelerate the appearance of insulin in the peripheral circulation.

Apolipoprotein (a) levels in type 1 and type 2 diabetes mellitus.

Type 1 and type 2 diabetes mellitus are both characterized by increased cardiovascular mortality and morbidity. Since several reports have indicated that apolipoprotein (a) [apo(a)] levels are positively associated with an increased risk of macrovascular disease, we investigated whether apo(a) levels are elevated in both types of diabetes mellitus and may thus represent an independent risk factor for atherosclerotic disease. Apo(a) concentrations in type 1 diabetic patients were not significantly different from matched controls (276 +/- 78 vs 149 +/- 46 units/l). Type 2 diabetic patients had considerably higher levels of apo(a) than matched controls (471 +/- 89 vs 221 +/- 61 units/l, P = 0.06), though the difference was not statistically significant. However, concentrations of apo(a) were above 300 units/l in 36% of type 1 and 67% of type 2 diabetic patients, but in only 14% and 25% respectively of matched control subjects. Plasma triglycerides were positively and independently correlated with apo(a) levels in both diabetic and non-diabetic subjects. On the other hand, no significant correlation was found between apo(a) levels and glycosylated haemoglobin, total cholesterol or high density lipoprotein cholesterol in any of the groups studied. In conclusion, apo(a) levels are not significantly elevated either in type 1 or type 2 diabetic patients without proteinuria and in moderate metabolic control; however, levels above 300 units/l were 2.6 times more frequent in both types of diabetes mellitus than in carefully age-, sex-, and weight-matched control subjects.