Willinger C C, Schramek H, Pfaller K, Joannidis M, Deetjen P, Pfaller W
Institute of Physiology, University of Innsbruck, Austria.
Ren Physiol Biochem. 1995 Nov-Dec;18(6):288-305. doi: 10.1159/000173929.
Since it became evident that organ dysfunctions after acute hemolysis are not induced by hemoglobin per se, but by stroma-contaminated hemoglobin, solutions of ultrapure stroma-free hemoglobins were regarded to be possible substitutes for blood in transfusion medicine. We tested one of the recently developed modified bovine hemoglobins (Ultrapure polymerized bovine hemoglobin 1; UPPBHb1) in the isolated perfused rat kidney (IPRK) model, using a recirculating system. Control kidneys were perfused with a substrate-enriched Ringer solution containing hydroxyethyl starch (HES) to produce isoncotic conditions. In the experimental group HES was substituted in part by UPPBHb1 (34 g/l). For determination of functional parameters, the kidneys were perfused for 180 min. A separate set of kidneys of both groups was perfusion fixed after 80 min of perfusion which is the period of optimal function. Light and electron microscopic analysis revealed major alterations only for the outer medulla of HES kidneys. Only these suffered from a considerable extent of proximal tubular S3 damage, exhibiting condensed tubular epithelia. In the inner stripe of the outer medulla, which is the zone of greatest sensitivity to damage in the isolated perfused kidney, severe hydropic degeneration, cell detachment, and necrotic destruction of the medullary thick ascending limb were seen in the HES-perfused group, too. In the UPPBHb1 group, the medullary thick ascending limb was well preserved, and S3 showed only a minor degree of damage. UPPBHB1 kidneys were further characterized by the occurrence of intracapillary and interstitial precipitates of UPPBHb1 in inner stripe of the outer medulla and inner medulla. The glomerular filtration rate was significantly higher in UPPBHb1-perfused kidneys (870 +/- 80 vs. 630 +/- 55 microliters/min/g kidney weight for HES). Absolute reabsorption of sodium paralleled the behavior of the glomerular filtration rate. The values for renal perfusate flow and urinary flow rate did not differ significantly between both groups. Renal autoregulation was better preserved in UPPBHb1-perfused kidneys (74 +/- 6% of full autoregulatory response) than in HES-perfused controls (42 +/- 4%). Our results suggest that perfusion of isolated rat kidneys with UPPBHb1 improves kidney function and morphology, providing better oxygenation than in control kidneys. UPPBHb1 does not exert additional nephrotoxic effects on the IPRK that will exceed the noxious potential of the method itself. Thus, it must be concluded that UPPBHb1 may be an oxyphoretic blood substitute with nephroprotective characteristics when compared with nonoxyphoretic substitutes. At least, UPPBHb1 seems to be a promising candidate as oxyphoretic additive to perfusates for the IPRK model.
由于急性溶血后器官功能障碍显然并非由血红蛋白本身引起，而是由受基质污染的血红蛋白所致，因此超纯无基质血红蛋白溶液被视为输血医学中血液的可能替代品。我们在离体灌注大鼠肾脏（IPRK）模型中，使用循环系统对最近开发的一种改良牛血红蛋白（超纯聚合牛血红蛋白1；UPPBHb1）进行了测试。对照肾脏用含有羟乙基淀粉（HES）的富含底物的林格溶液灌注以产生等渗条件。在实验组中，HES部分被UPPBHb1（34 g/l）替代。为了测定功能参数，肾脏灌注180分钟。两组的另一组肾脏在灌注80分钟后进行灌注固定，这是最佳功能期。光镜和电镜分析显示仅HES组肾脏的外髓质有主要改变。只有这些肾脏近端肾小管S3段有相当程度的损伤，表现为肾小管上皮细胞浓缩。在外髓质的内带，即离体灌注肾脏中对损伤最敏感的区域，HES灌注组也可见严重的水样变性、细胞脱落以及髓袢升支粗段的坏死性破坏。在UPPBHb1组中，髓袢升支粗段保存良好，S3段仅显示轻微损伤。UPPBHB1组肾脏的特征还在于在外髓质内带和内髓质出现UPPBHb1 的毛细血管内和间质沉淀。UPPBHb1灌注的肾脏肾小球滤过率显著更高（870±80 vs. HES组630±55微升/分钟/克肾脏重量）。钠的绝对重吸收与肾小球滤过率的变化趋势一致。两组之间的肾脏灌注液流量和尿流率值无显著差异。UPPBHb1灌注的肾脏肾自动调节功能比HES灌注的对照组保存更好（完全自动调节反应的74±6%）。我们的结果表明，用UPPBHb1灌注离体大鼠肾脏可改善肾脏功能和形态，比对照肾脏提供更好的氧合。UPPBHb1对IPRK不会产生超过该方法本身潜在有害作用的额外肾毒性作用。因此，可以得出结论，与非携氧替代品相比，UPPBHb1可能是一种具有肾保护特性的携氧血液替代品。至少，UPPBHb1似乎是IPRK模型灌注液中有前景的携氧添加剂候选物。
