Tompkins R G
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge 02139.
Am J Physiol. 1991 Apr;260(4 Pt 2):H1194-204. doi: 10.1152/ajpheart.1991.260.4.H1194.
A mathematical transport model was derived to analyze in vivo low-density lipoprotein (LDL) transport across the aorta, peripheral muscular arteries, and major veins of squirrel monkeys (primates that develop diet-induced atherosclerosis similar to humans). Parameters determining the relative magnitudes of intimal permeability and diffusion within the vascular wall were optimized by nonlinear regression methods. Transmural LDL concentrations demonstrating discrete spatial resolution along the endothelial surface were previously obtained after 30 min of tracer circulation using quantitative autoradiography. In this study, intimal mass transfer coefficient (k1) was determined in 87 vascular regions representing 280 transmural profiles. As a result of this analysis, the value of k1 was 1.7 +/- 0.4 x 10(-9) cm/s for arteries, 2.9 +/- 0.3 x 10(-9) cm/s for veins, and 60 +/- 120 x 10(-9) cm/s for enhanced LDL uptake regions, which was a significant increase (P less than 0.01). The effective diffusion coefficient was 6.2 +/- 3.7 x 10(-10) cm2/s for all vascular regions examined. As a result of this analysis, focal regions of enhanced LDL uptake were explained solely on the basis of intimal permeability.
推导了一个数学转运模型，以分析松鼠猴（一种与人类一样会因饮食诱导发生动脉粥样硬化的灵长类动物）体内低密度脂蛋白（LDL）在主动脉、外周肌性动脉和大静脉中的转运情况。通过非线性回归方法优化了决定血管壁内膜通透性和扩散相对大小的参数。使用定量放射自显影技术，在示踪剂循环30分钟后，先前已获得沿内皮表面具有离散空间分辨率的跨壁LDL浓度。在本研究中，在代表280个跨壁剖面的87个血管区域测定了内膜传质系数（k1）。分析结果显示，动脉的k1值为1.7±0.4×10⁻⁹ cm/s，静脉为2.9±0.3×10⁻⁹ cm/s，LDL摄取增强区域为60±120×10⁻⁹ cm/s，后者有显著增加（P<0.01）。在所检查的所有血管区域，有效扩散系数为6.2±3.7×10⁻¹⁰ cm²/s。分析结果表明，LDL摄取增强的局部区域仅基于内膜通透性来解释。
