The purpose of this study was to evaluate change in glycosylated hemoglobin (HbA1c), side effects, and quality of life (QOL) after a 16-week treatment period with Biphasic insulin aspart 30/70 (BIasp30) in patients with type 2 diabetes mellitus (T2DM) who had been suboptimally controlled with oral antidiabetic drugs (OADs).

The study consisted of a 4-week titration period when concurrent OAD(s) were replaced with BIasp30 and followed by a 12-week maintenance period. All patients completed the Diabetes Treatment Satisfaction Questionnaire at the beginning and the end of the trial. Hypoglycemic episodes were recorded by the patient throughout the trial.

Sixty patients were included, of whom 55 patients (92%) completed the full 16-week treatment period. Seven-point blood glucose was significantly improved as compared with the baseline, except for the postlunch blood glucose level. HbA1c at the end of period was significantly improved from 9.2% to 8.2% (P<0.001). Eleven percent (n=6) of patients achieved HbA1c values ≤6.5% and 22% (n=12) of patients achieved <7.0%. There were 3.4 episodes/patients-year of minor hypoglycemia and 0.05 episodes/patients-year of major hypoglycemia. QOL showed significant changes only in the acceptability of high blood glucose category (P=0.003).

Treatment with once or twice daily BIasp30 may be an option for the patients with T2DM suboptimally controlled with OADs in Korea. However, considering the low number of patients achieving the HbA1c target and the high postlunch blood glucose levels, additional management with another modality may be required for optimal control.

Insulin-mediated glucose uptake in insulin target tissues is correlated with interstitial insulin concentration, rather than plasma insulin concentration. Therefore, insulin delivery to the interstitium of target tissues is very important, and the endothelium may also play an important role in the development of insulin resistance.

After treating bovine aortic endothelial cells with angiotensin II (ATII), we observed the changes in insulin binding capacity and the amounts of insulin receptor (IR) on the cell membranes and in the cytosol.

After treatment of 10^-7M ATII, insulin binding was decreased progressively, up to 60% at 60 minutes (P<0.05). ATII receptor blocker (eprosartan) dose dependently improved the insulin binding capacity which was reduced by ATII (P<0.05). At 200 µM, eprosartan fully restored insulin binding capacity, althogh it resulted in only a 20% to 30% restoration at the therapeutic concentration. ATII did not affect the total amount of IR, but it did reduce the amount of IR on the plasma membrane and increased that in the cytosol.

ATII decreased the insulin binding capacity of the tested cells. ATII did not affect the total amount of IR but did decrease the amount of IR on the plasma membrane. Our data indicate that ATII decreases insulin binding by translocating IR from the plasma membrane to the cytosol. The binding of insulin to IR is important for insulin-induced vasodilation and transendothelial insulin transport. Therefore, ATII may cause insulin resistance through this endothelium-based mechanism.