Katsuda Shin-ichiro, Miyashita Hiroshi, Takazawa Kenji, Machida Noboru, Kusanagi Masahiko, Miyake Masao, Hazama Akihiro
Department of Physiology, Fukushima Medical University School of Medicine, 1, Hikari-ga-oka, Fukushima 960-1295, Japan.
Physiol Meas. 2006 Dec;27(12):1361-71. doi: 10.1088/0967-3334/27/12/008. Epub 2006 Nov 10.
The coexistence of hypertension and hypercholesterolaemia from youth may increase the prevalence of and mortality from cardiovascular disease and stroke. We thus investigated haemodynamics of mild hypertension in young Kurosawa and Kusanagi-hypercholesterolaemic (KHC) rabbits aged 10-12 months old, as models of heritable hypercholesterolaemia. Pressure and flow waves were simultaneously recorded at the ascending aorta with a catheter-tip micromanometer and ultrasonic flow meter under pentobarbital anaesthesia, respectively. Systolic (119.3 +/- 6.5 and 138.4 +/- 7.4 mmHg (mean +/- SD) for control and KHC rabbit groups; p < 0.001), diastolic (95.7 +/- 6.1 and 109.8 +/- 5.2; p < 0.001), mean (105.8 +/- 6.5 and 122.5 +/- 4.9; p < 0.001) and pulse (23.7 +/- 2.5 and 28.6 +/- 4.0; p < 0.001) pressures as well as total peripheral vascular resistance (0.32 +/- 0.02 and 0.37 +/- 0.03 mmHg/ml/min; p < 0.001) were significantly greater in the KHC rabbit group than those in the age-matched control rabbit group, respectively, while there were no significant differences in the mean aortic flow, heart rate or stroke volume between the two rabbit groups. Aortic input impedance (p < 0.05) and reflection coefficient (p < 0.05) were significantly greater at lower frequency in the KHC rabbit group than in the control rabbit group, whereas there was no significant difference in the characteristic impedance between the two rabbit groups. Plasma angiotensin I (p < 0.01) and II (p < 0.01) levels and serum angiotensin converting enzyme activity (p < 0.05) were significantly greater in the KHC rabbit group than in the age-matched control rabbit group. Atheromatous plaque was in the early stage and composed mainly of abundant foam cells. Neither sclerotic lesions nor stenosis were observed in main peripheral arteries. The mild hypertension in young KHC rabbits was due partly to the increased activity of the renin-angiotensin system. These findings may be thought provoking in elucidating the mechanism and developing preventive and therapeutic strategies in young patients with coexistent hypertension and hypercholesterolaemia.
年轻时高血压与高胆固醇血症并存可能会增加心血管疾病和中风的患病率及死亡率。因此，我们以遗传性高胆固醇血症模型，研究了10至12个月大的黑泽和草薙高胆固醇血症（KHC）幼兔轻度高血压的血流动力学情况。在戊巴比妥麻醉下，分别用导管尖端微压计和超声流量计同时记录升主动脉的压力波和血流波。收缩压（对照组和KHC兔组分别为119.3±6.5和138.4±7.4 mmHg（均值±标准差）；p<0.001）、舒张压（95.7±6.1和109.8±5.2；p<0.001）、平均压（105.8±6.5和122.5±4.9；p<0.001）和脉压（23.7±2.5和28.6±4.0；p<0.001）以及总外周血管阻力（0.32±0.02和0.37±0.03 mmHg/ml/min；p<0.001）在KHC兔组均显著高于年龄匹配的对照组，而两组兔的平均主动脉血流量、心率或每搏输出量无显著差异。KHC兔组在较低频率时的主动脉输入阻抗（p<0.05）和反射系数（p<0.05）显著高于对照组，而两组的特性阻抗无显著差异。KHC兔组的血浆血管紧张素I（p<0.01）和II（p<0.01）水平以及血清血管紧张素转换酶活性（p<0.05）显著高于年龄匹配的对照组。动脉粥样斑块处于早期阶段，主要由大量泡沫细胞组成。主要外周动脉未观察到硬化病变或狭窄。幼龄KHC兔的轻度高血压部分归因于肾素-血管紧张素系统活性增加。这些发现可能会引发人们对年轻高血压与高胆固醇血症并存患者的发病机制及预防和治疗策略的思考。
