Effects of multiple daily injection therapy with Humalog mixtures versus separately injected insulin lispro and NPH insulin in adults with type I diabetes mellitus.

BACKGROUND: Injection of insulin lispro (LP) before meals provides a more physiologic insulin activity profile than regular human insulin, but the relatively short duration of action of LP may allow the blood glucose (BG) level to increase during the late postprandial period (4-7 hours after meals) unless basal insulin is optimally replaced. One approach to basal insulin optimization has been to combine small doses of NPH with LP before meals. When used in a similar fashion, premixed, fixed-ratio insulin preparations containing LP and NPL (an LP-based intermediate-acting insulin) may provide the basis for an optimized basal-bolus insulin regimen. OBJECTIVE: This study assessed mean late postprandial glycemic control during treatment with a premixed formulation consisting of a high proportion of LP (75% LP/25% NPL; H) and a premixed formulation consisting of a medium proportion of LP (50% LP/50% NPL; M). The H/M formulation was given before meals and was compared with treatment with preprandial LP + NPH (LP + N) in patients with type 1 diabetes mellitus (DM). METHODS: This multicenter, randomized, open-label, 2-period crossover study was conducted at 4 centers in Italy and 1 center in France. Patients eligible for the study had type 1 DM, were > or = 18 years of age, and had a glycosylated hemoglobin (HbA(1c)) <150% of the upper limit of normal. Patients were randomly assigned to 1 of 2 treatment sequences: LP self-mixed with NPH before meals plus NPH alone at bedtime for 8 weeks (LP + N) followed by preprandial H or M, plus NPH alone at bedtime for 8 weeks (H/M), or the opposite sequence. Assessments included 8-point self-monitored BG profiles, HbA(1c), and hypoglycemia (any sign or symptom of hypoglycemia or BG < 3.0 mmol/L [<54.0 mg/dL]). The primary outcome measure was the late postprandial BG value, calculated as the mean of the combined prelunch (late postbreakfast), predinner (late postlunch), and bedtime (late postdinner) values. RESULTS: A total of 89 patients with type 1 DM were enrolled (44 men, 45 women; mean [SD] age, 38.3 [12.8] years; mean [SD] body weight, 70.8 [11.6] kg; mean [SD] body mass index, 24.6 [3.0] kg/m(2); mean [SD] duration of diabetes, 17.8 [10.5] years; mean HbA(1c), 7.9% [0.88%]). The mean (SD) late postprandial BG values were similar between treatments (8.9 [2.1] mmol/L [160.3 (37.8) mg/dL] for H/M vs 9.0 [1.8] mmol/L [162.1 (32.4) mg/dL] for LP + N), as were the end point HbA(1c) values (7.8% [0.9%] for H/M vs 7.9% [0.8%] for LP + N). The rate of hypoglycemia was significantly higher during treatment with H/M, primarily because of episodes occurring between 12 PM and 6 PM, but was relatively low in both groups (mean/median rate per patient per 30 days: 2.87/2.14 for H/M and 2.11/1.07 for LP + N; P < 0.05). CONCLUSIONS: In this population of patients with type 1 DM, preprandial H/M provided an effective alternative regimen for prandial and basal insulin replacement. Late postprandial BG control, an indicator of basal insulin sufficiency, was similar to that achieved with an intensified regimen of LP + N injected separately before meals, and the end point HbA(1c) was similar between the 2 treatments.

Evidence for an independent and cumulative effect of postprandial hypertriglyceridemia and hyperglycemia on endothelial dysfunction and oxidative stress generation: effects of short- and long-term simvastatin treatment.

BACKGROUND: Postprandial hypertriglyceridemia and hyperglycemia are considered risk factors for cardiovascular disease. Evidence suggests that postprandial hypertriglyceridemia and hyperglycemia induce endothelial dysfunction through oxidative stress; however, the distinct role of these two factors is a matter of debate. METHODS AND RESULTS: Thirty type 2 diabetic patients and 20 normal subjects ate 3 different meals: a high-fat meal; 75 g glucose alone; and high-fat meal plus glucose. Glycemia, triglyceridemia, nitrotyrosine, and endothelial function were assayed during the tests. Subsequently, diabetics took 40 mg/d simvastatin or placebo for 12 weeks. The 3 tests were performed again at baseline, between 3 to 6 days after the start, and at the end of each study. High-fat load and glucose alone produced a decrease of endothelial function and an increase of nitrotyrosine in normal and diabetic subjects. These effects were more pronounced when high fat and glucose were combined. Short-term simvastatin treatment had no effect on lipid parameters but reduced the effect on endothelial function and nitrotyrosine observed during each different test. Long-term simvastatin treatment was accompanied by a lower increase in postprandial triglycerides, which was followed by smaller variations of endothelial function and nitrotyrosine during the tests. CONCLUSIONS: This study shows an independent and cumulative effect of postprandial hypertriglyceridemia and hyperglycemia on endothelial function, suggesting oxidative stress as common mediator of such effect. Simvastatin shows a beneficial effect on oxidative stress and endothelial dysfunction, which may be ascribed to a direct effect as well as the lipid-lowering action of the drug.

Role of hyperglycemia in nitrotyrosine postprandial generation.

OBJECTIVE: Recently, much attention has been paid to the possibility that postprandial hyperglycemia may be a cardiovascular risk factor in diabetes. Oxidative stress has been involved in the pathogenesis of diabetic complications, and increased plasma levels of nitrotyrosine, a product of peroxynitrite action, have been found in the plasma of diabetic subjects. The aim of the present study was to evaluate whether postprandial hyperglycemia is accompanied by nitrotyrosine generation and, if so, to explore a possible direct role of hyperglycemia in such a phenomenon. RESEARCH DESIGN AND METHODS: A total of 23 type 2 diabetic patients and 15 matched normal healthy subjects were recruited for this study. Two different tests were performed in diabetic patients: a standard meal preceded by regular insulin (0.15 units/kg body wt) or insulin aspart (0.15 units/kg body wt) to achieve different levels of postprandial hyperglycemia. The meal test was also performed in healthy control subjects. At 0 min and 1, 2, 4, and 6 h after each meal, blood glucose, triglyceride, and nitrotyrosine levels were measured. RESULTS: Fasting nitrotyrosine was significantly increased in diabetic patients and was further increased during both meal tests in diabetic subjects but not normal subjects. As compared with regular insulin, aspart administration significantly reduced the area under the curve of both glycemia (P < 0.04) and nitrotyrosine (P < 0.03), whereas that of triglycerides was not significantly affected by the treatment. CONCLUSIONS: This study shows a direct correlation between postprandial hyperglycemia and the production of nitrotyrosine, a marker of oxidative stress, in patients with type 2 diabetes.