耐糖能異常者における小粒子径低比重リポ蛋白と血中脂質, 肥満およびインスリン感受性との関係

Abstract

We examined plasma LDL particle size in 55 patients (35 males, 20 females) with NIDDM (diet alone) or IGT (WHO), and investigated the relationship between LDL particle size and plasma lipids, obesity, and peripheral insulin sensitivity. 55 healthy adults of similar sex, age, and body mass index (BMI) were used as a control group. Peak LDL particle size was measured by nondenaturing 2% to 16% polyacrylamide gradient gel electrophoresis and oil red O staining. In this study any LDL particle size less than 25.7nm was defined as “small LDL”, and anything over 25.7nm was defined as “normal LDL”. The mean peak LDL particle sizes of the patients and controls were 25.81±0.79 and 26.66±0.75nm, respectively. The frequency of small LDL in the patients was significantly higher than that in the control group (43.6% vs. 5.5%). In the patients, there was no difference in the blood pressure in the small LDL group and the normal LDL group. The total cholesterol, triglyceride, and apo B levels in both male and female patients were significantly higher in the small LDL group than in the normal LDL group. By contrast, the HDL-C level in male patients was significantly lower in the small LDL group. The BMI and the ratio of waist-to-hip circumference in both male and female patients tended to be higher in the small LDL groups than those in the normal LDL groups (female: 27.1±4.2vs. 22.4±5.4, 1.004±0.041vs. 0.911±0.066; male: 26.1±2.5vs. 23.7±3.6, 0.956±0.036vs. 0.931±0.043). Moreover the ratio of intra-abdominal visceral fat to subcutaneous fat, which was measured using an abdominal CT scan, was higher in the small LDL group of male patients (0.549±0.135vs. 0.382±0.069). The fasting IRI levels of both male and female patients were significantly higher in the small LDL groups than those in the normal LDL groups (female: 19.38±16.80vs. 9.17±4.84μU/ml; male: 12.45±7.67vs. 7.14±3.22μU/ml). A euglycemic insulin clamp study showed that the glucose disposable rate in the small LDL group was significantly lower than that in the healthy control group (female: 2.34±0.04vs. 7.90±1.57mg/min/kg; male: 3.61±1.79vs. 7.11±1.38mg/min/kg). These results suggest that glucose intolerance in the small LDL group is closely related to hypertriglyceridemia, low HDL-C, visceral obesity and peripheral insulin resistance.