Postprandial Glucose Spikes Research Articles

The features of postprandial glucose state in type 2 diabetes mellitus

To study the features of postprandial glucose state in individuals with normal glucose regulation (NGR) and type 2 diabetes (T2DM) and the relations between hemoglobin A1c (HbA1c) and postprandial glucose in T2DM. 41 NGR individuals and 60 newly diagnosed T2DM patients without previous management in Shanghai were measured by continuous glucose monitoring system for 3 days. The postprandial glucose spike (PGS), time to PGS (Deltat), postprandial glucose excursion (PPGE), duration of postprandial glucose (DUR) and incremental area under the curve of postprandial glucose (IAUC) were calculated in each individual. (1) The levels of PGS and Deltat in the T2DM group were significantly higher than those of the NGR group (all P < 0.01). The levels of PPGE, DUR and IAUC of the T2DM group were 5.87 mmol/L +/- 0.19 mmol/L, 14.1 h +/- 0.3 h and 2.04 mmol.L(-1).d +/- 0.09 mmol.L(-1).d respectively, all significantly higher than those of the NGR group (2.10 mmol/L +/- 0.12 mmol/L, 8.3 h +/- 0.4 h and 0.43 mmol.L(-1).d +/- 0.03 mmol.L(-1).d respectively, all P < 0.01). The breakfast had higher PGS and lower Deltat than those of lunch and dinner in the T2DM group (both P < 0.01). The PPGE was arranged from high to low in the order of breakfast, dinner and lunch. The highest IAUC appeared during dinner. (2) There was a significantly correlation between PPGE and IAUC (r = 0.93, P < 0.01) in the T2DM group. After being adjusted by preprandial glucose, the partial correlation of HbA1c and IAUC disappeared (before r = 0.29, P = 0.03, after P = 0.05). (3) The relative contribution of postprandial glucose to overall glucose levels in the T2DM group was significantly higher than that of the NGR group (18.1% +/- 0.8% vs 8.0% +/- 0.7%, P < 0.01), but both were significantly lower than those of preprandial glucose. (4) Relative contribution of postprandial hyperglycemia to overall diurnal hyperglycemia decreased progressively from the lowest to the highest quarter of HbA1c. By contrast, the relative contribution of preprandial hyperglycemia showed a significant increase with increasing levels of HbA1c. Postprandial hyperglycemia played a major role when the HbA1c level below 7.5% (P < 0.05). (1) The features of postprandial glucose state in T2DM is representative in the delay of PGS and excessive glucose excursion for a long time after the ingestion of a meal. (2) HbA1c can't reflect postprandial glucose excursions. PPGE can be used as a simple clinic index to evaluate the amplitude of postprandial glucose excursions. (3) Postprandial glucose excursions play a major role in T2DM suffering from mild or moderate hyperglycemia. The present results suggest that postprandial hyperglycemia is an important target for intervention when T2DM patients are approaching the ideal glycemic control.

Significance of postprandial glucose peaks for development of diabetic macroangiopathy

Type-2 diabetes is associated with an excessively high mortality and morbidity due to cardiovascular disease. Numerous studies have demonstrated the relevance of postprandial hyperglycemia for atherosclerosis. Moreover, the form of isolated postprandial diabetes seems to be much more common than expected. Even mild postprandial hyperglycemia in the form of impaired glucose tolerance was shown to be associated with an increased rate of cardiovascular disease. This indicates the necessity of using OGTT in the screening of high-risk populations in order to detect asymptomatic diabetic subjects and enable appropriate treatment in time. Not using the OGTT would mean missing a large cohort of undiagnosed diabetic subjects, particularly among older people. Since an OGTT cannot be generally conducted, we recommend its performance in risk subjects and especially in elderly women. This would make it possible to institute preventive measures.

Nateglinide: A structurally novel, short-acting, hypoglycemic agent.

Nateglinide is a short-acting, pancreatic, beta-cell-selective, K(ATP) potassium channel blocker that improves overall glycemic control in type 2 diabetes. Although nateglinide's mechanism of action is related to that of sulphonyl-ureas and repaglinide, important differences do exist. Nateglinide binds rapidly to the sulfonylurea SUR1 receptor with a relatively low affinity, and it dissociates from it extremely rapidly in a manner of seconds. This rapid association and dissociation gives nateglinide a unique "fast on-fast off" effect. Thus, nateglinide has a rapid onset and short duration of action stimulating insulin secretion in vivo and providing good control of postprandial hyperglycemia when taken immediately prior to meals. The rapid action of nateglinide on the beta cells stimulates and restores the normal physiological first and early phase of insulin secretion, consequently reducing postprandial hyperglycemia. This hypoglycemic effect of nateglinide leads to improved glycemic control, while the short duration avoids delayed hyperinsulinemia and hypoglycemia after meals. Nateglinide is not a sulfonylurea, but it shares the mechanism of action of commonly used oral hypoglycemic agents such as glibenclamide and glipizide. Like the recently introduced, short-acting agent, repaglinide, it does not incorporate a sulfonylurea moiety. However, nateglinide's effects on insulin secretion and glycemic control differ significantly from the sulfonylureas and repaglinide in that it preferentially stimulates acute phase insulin, better controls postprandial glucose excursions and spikes, and causes less hyperinsulinemia and hypoglycemia. Compounds with such a profile should not only achieve improved overall glucose control, but also reduce the risk of vascular complications which is the most important feature of nateglinide. Clinical studies with nateglinide have confirmed that it acts rapidly and both restores insulin release and attenuates the postprandial glucose spike. Nateglinide is both effective and well tolerated in the treatment of type 2 diabetes. The reported overall profile of adverse effects appears to be superior to that of other K(ATP) potassium channel blockers, the glucose modulator metformin and PPARgamma agonists such as troglitazone. Clinical comparisons of these agents have shown nateglinide to be more effective in attenuating postprandial glucose than any other oral hypoglycemic agent, and that treatment with both nateglinide and metformin provides additive effects that afford improved control of plasma glucose levels. The administration regimen for nateglinide, immediately prior to meals, also facilitates patient compliance. (c) 2001 Prous Science. All rights reserved.

Postprandial glucose and vascular disease.

The high plasma glucose concentrations in patients with diabetes are associated with an increased risk of vascular disease. In patients with non-insulin-dependent diabetes mellitus, vascular changes often predate clinical diagnosis of hyperglycaemia. Impaired glucose tolerance precedes diabetes and may therefore be an important phase in the development of vascular changes. There is evidence to suggest that hyperglycaemia interferes with the activity and function of endothelial cells. In vitro data show that high glucose concentrations can activate protein kinase C (PKC) in endothelial cells, specifically PKC alpha. This activation appears to stimulate expression of adhesion molecules on endothelial cells, facilitating the adhesion and uptake of leukocytes into the endothelium. In addition, high glucose concentrations affect the permeability of tight junctions between endothelial cells, which also seems to be mediated by PKC. Thus, PKC activation may be central to the effects of glucose-stimulated vascular changes. Evidence for direct stimulation of endothelial cells by glucose may support the hypothesis that postprandial glucose spikes are important in the early development of micro- and macrovascular disease.