Amann K, Breitbach M, Ritz E, Mall G
Department of Pathology, University of Heidelberg, Germany.
J Am Soc Nephrol. 1998 Jun;9(6):1018-22. doi: 10.1681/ASN.V961018.
Experiments indicate that capillary density is reduced in the hypertrophied left ventricle of rats with subtotal nephrectomy compared to control rats with similar BP and left ventricular hypertrophy, suggesting that in uremia, hypertrophying cardiomyocytes outgrow their capillary supply. No information on myocardial capillary supply in humans is currently available. The hearts of nine dialyzed patients, nine patients with essential hypertension, and 10 normotensive control subjects at postmortem were obtained. Subjects with stenosing coronary lesions and left ventricular pump failure were excluded. Special sampling procedures were used to exclude stereologic artefacts. Capillaries were specifically stained with ulex lectin and analyzed by stereologic techniques. Length density of myocardial capillaries (Lv; mm/mm3) was significantly (P < 0.001) lower in dialyzed patients (1483 +/- 238) than in patients with essential hypertension (1872 +/- 243) or in normotensive control patients (2898 +/- 456). In parallel, myocyte diameter and volume density of myocardial interstitial tissue were significantly (P < 0.001) increased in uremic patients compared to patients with essential hypertension and control patients, respectively. Diminished left ventricular capillary supply in renal failure must increase critical oxygen diffusion distance in the myocardium, thus exposing cardiomyocytes to the risk of hypoxia. It is unknown whether such reduced ischemia tolerance can be reversed by increasing oxygen supply (e.g., by reversing anemia).
实验表明，与血压和左心室肥厚情况相似的对照大鼠相比，次全肾切除大鼠肥厚的左心室中毛细血管密度降低，这表明在尿毒症中，肥大的心肌细胞生长超过了其毛细血管供应。目前尚无关于人类心肌毛细血管供应的信息。获取了9例透析患者、9例原发性高血压患者和10例血压正常对照者死后的心脏。排除有冠状动脉狭窄病变和左心室泵衰竭的受试者。采用特殊的采样程序以排除体视学假象。用荆豆凝集素对毛细血管进行特异性染色，并通过体视学技术进行分析。透析患者心肌毛细血管的长度密度（Lv；mm/mm³）（1483±238）显著低于原发性高血压患者（1872±243）或血压正常对照患者（2898±456）（P<0.001）。同时，与原发性高血压患者和对照患者相比，尿毒症患者的心肌细胞直径和心肌间质组织的体积密度分别显著增加（P<0.001）。肾衰竭时左心室毛细血管供应减少必然会增加心肌中的临界氧扩散距离，从而使心肌细胞面临缺氧风险。目前尚不清楚这种降低的缺血耐受性是否可以通过增加氧供应（如纠正贫血）来逆转。
