Miller A, Mujumdar V, Shek E, Guillot J, Angelo M, Palmer L, Tyagi S C
Department of Physiology and Biophysics, School of Medicine, The University of Mississippi Medical Center, Jackson 39216-4505, USA.
Heart Vessels. 2000;15(3):135-43. doi: 10.1007/s003800070030.
Hyperhomocyst(e)inemia has been associated with the development of hypertension, stroke, and cardiovascular, cerebral/neuronal, renal, and liver diseases. To test the hypothesis that homocyst(e)ine plays an integrated role in multiorgan injury in hypertension, we employed: (1) spontaneously hypertensive rats (SHR) in which endogenous homocyst(e)ine levels are moderately high (18.1 +/- ().5 microM); (2) control age- and sex-matched Wistar Kyoto (WKY) rats in which homocyst(e)ine levels are normal (3.7 +/- 0.3 microM). To create the pathophysiological condition of hyperhomocyst(e)inemia, 20 mg/day homocyst(e)ine was administered for 12 weeks in (3) SHR (SHR-H) and in (4) WKY (WKY-H) rats. (5) Endogenous homocyst(e)ine levels were reduced slightly but not significantly from 18.1 +/- 0.5 microM to 12.5 +/- 0.7 microM in SHR by folic acid administration (SHR-F). Plasma and tissue levels of homocyst(e)ine were determined by HPLC and spectrophotometric methods. Plasma and sympathetic ganglion (neuronal) matrix metalloproteinase (MMP) activity was measured by zymography. Activity of neuronal MMP was increased in hyperhomocyst(e)inemic rats as compared with controls. Mean arterial pressure (mmHg) was 95 +/- 5, 126 +/- 8,157 +/- 10, 188 +/- 5, and 165 +/- 12 in WKY, WKY-H, SHR, SHR-H, and SHR-F, respectively. Urinary protein (mg/day) was 0.11 +/- 0.03, 0.88 +/- 0.22, 0.47 +/- 0.10, 0.89 +/- 0.21, and 0.81 +/- 0.21 in WKY, WKY-H. SHR, SHR-H, and SHR-F, respectively, as measured by the Bio-Rad dye binding assay. The relationships between increased arterial pressure, plasma homocyst(e)ine, and urinary protein were delineated. Plasma and neuronal creatinine phosphokinase (CK) isoenzymes were measured by agarose gel electrophoresis. All three CK isoenzymes, i.e., MM, MB, and BB, specific for skeletal, cardiac, and nerve tissue, respectively, were induced following 12 weeks' hyperhomocyst(e)inemia, suggesting multiorgan injury by homocyst(e)ine. Homocyst(e)ine induces endocardial endothelial cell (capillary) apoptosis and may reduce capillary cell density. Structural damage to aorta, myocardium, kidney, and renalureter was analyzed by histology. Results suggested an integrated physiological role of homocyst(e)ine in injury to the endothelial/epithelial cell lining in the respective organs.
高同型半胱氨酸血症与高血压、中风以及心血管、脑/神经元、肾脏和肝脏疾病的发生有关。为了验证同型半胱氨酸在高血压多器官损伤中起综合作用这一假说，我们采用了：（1）内源性同型半胱氨酸水平中度升高（18.1±0.5微摩尔/升）的自发性高血压大鼠（SHR）；（2）同型半胱氨酸水平正常（3.7±0.3微摩尔/升）的年龄和性别匹配的Wistar Kyoto（WKY）对照大鼠。为了制造高同型半胱氨酸血症的病理生理状况，分别对（3）SHR（SHR-H）和（4）WKY（WKY-H）大鼠每日给予20毫克同型半胱氨酸，持续12周。（5）通过给予叶酸（SHR-F），SHR的内源性同型半胱氨酸水平从18.1±0.5微摩尔/升略有降低但不显著，降至12.5±0.7微摩尔/升。采用高效液相色谱法和分光光度法测定血浆和组织中的同型半胱氨酸水平。通过酶谱法测量血浆和交感神经节（神经元）基质金属蛋白酶（MMP）活性。与对照组相比，高同型半胱氨酸血症大鼠的神经元MMP活性增加。WKY、WKY-H、SHR、SHR-H和SHR-F的平均动脉压（毫米汞柱）分别为95±5、126±8、157±10、188±5和165±12。采用Bio-Rad染料结合法测定，WKY、WKY-H、SHR、SHR-H和SHR-F的尿蛋白（毫克/天）分别为0.11±0.03、0.88±0.22、0.47±0.10、0.89±0.21和0.81±0.21。明确了动脉压升高、血浆同型半胱氨酸和尿蛋白之间的关系。采用琼脂糖凝胶电泳法测量血浆和神经元肌酸磷酸激酶（CK）同工酶。在12周的高同型半胱氨酸血症后，分别对骨骼肌、心脏和神经组织特异的所有三种CK同工酶，即MM、MB和BB均有诱导，提示同型半胱氨酸导致多器官损伤。同型半胱氨酸诱导心内膜内皮细胞（毛细血管）凋亡，并可能降低毛细血管细胞密度。通过组织学分析主动脉、心肌、肾脏和肾盂输尿管的结构损伤。结果提示同型半胱氨酸在各器官内皮/上皮细胞内衬损伤中起综合生理作用。
