OBJECTIVES: The objective of this study was to determine the impact of insulin and glucose on myocardial vasodilator function in patients with type 1 diabetes mellitus(T1DM). BACKGROUND: The relative importance of pla...OBJECTIVES: The objective of this study was to determine the impact of insulin and glucose on myocardial vasodilator function in patients with type 1 diabetes mellitus(T1DM). BACKGROUND: The relative importance of plasma insulin and glucose levels on the abnormal vasodilator function observed in T1DM is unknown. METHODS: Twenty T1DM patients underwent positron emission tomography studies to measure myocardial blood flow(MBF)(in ml/g/min) at rest(MBFr) and during adenosine(MBFa), both under baseline metabolic conditions and then during either hyperinsuline-miceuglycemic clamp(HE)(n=10; 40±9 years, 8 female subjects, hemoglobin A1c HbA1c 7.8±1.1%) or hyperinsulinemic-hyperglycemic clamp(HH)(n=10; 44±12 years, 8 female subjects, hemoglobin A1c 7.7±0.6%). RESULTS: Both groups showed similar MBFr and MBFa under baseline metabolic conditions(p=NS). Compared with baseline conditions, MBFr increased in the HH group(p< 0.005), whereas it did not change in the HE group. Compared with baseline conditions, MBFa decreased in the HH group(p< 0.05) but did not change in the HE group. Myocardial perfusion reserve(MPR)(MBFa /MBFr) was similar between the HE and HH groups at baseline(p=NS). During clamp, MPR tended to decrease in the HH group(p< 0.1) but did not change in the HE group(p=NS) when compared with baseline conditions. However, during the clamp MPR was significantly lower in the HH group when compared with the HE group(p< 0.0001). CONCLUSIONS: In the short term, hyperglycemia has a deleterious effect on myocardial vasodilator function, which outweighs the beneficial effect of hyperinsulinemia.展开更多
文摘OBJECTIVES: The objective of this study was to determine the impact of insulin and glucose on myocardial vasodilator function in patients with type 1 diabetes mellitus(T1DM). BACKGROUND: The relative importance of plasma insulin and glucose levels on the abnormal vasodilator function observed in T1DM is unknown. METHODS: Twenty T1DM patients underwent positron emission tomography studies to measure myocardial blood flow(MBF)(in ml/g/min) at rest(MBFr) and during adenosine(MBFa), both under baseline metabolic conditions and then during either hyperinsuline-miceuglycemic clamp(HE)(n=10; 40±9 years, 8 female subjects, hemoglobin A1c HbA1c 7.8±1.1%) or hyperinsulinemic-hyperglycemic clamp(HH)(n=10; 44±12 years, 8 female subjects, hemoglobin A1c 7.7±0.6%). RESULTS: Both groups showed similar MBFr and MBFa under baseline metabolic conditions(p=NS). Compared with baseline conditions, MBFr increased in the HH group(p< 0.005), whereas it did not change in the HE group. Compared with baseline conditions, MBFa decreased in the HH group(p< 0.05) but did not change in the HE group. Myocardial perfusion reserve(MPR)(MBFa /MBFr) was similar between the HE and HH groups at baseline(p=NS). During clamp, MPR tended to decrease in the HH group(p< 0.1) but did not change in the HE group(p=NS) when compared with baseline conditions. However, during the clamp MPR was significantly lower in the HH group when compared with the HE group(p< 0.0001). CONCLUSIONS: In the short term, hyperglycemia has a deleterious effect on myocardial vasodilator function, which outweighs the beneficial effect of hyperinsulinemia.
