Wang Aizhou, Singh Serena, Yu Binglan, Bloch Donald B, Zapol Warren M, Kluger Ronald
Davenport Chemistry Research Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada.
Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
Transfusion. 2019 Jan;59(1):359-370. doi: 10.1111/trf.15003. Epub 2018 Nov 15.
Hemoglobin-based oxygen carriers (HBOCs) are potential alternatives to red blood cells in transfusions. Clinical trials using early versions of HBOCs noted adverse effects that appeared to result from removal of the vasodilator nitric oxide (NO). Previous reports suggest that size-enlarged HBOCs may avoid NO-rich regions along the vasculature and therefore not cause vasoconstriction and hypertension.
Hemoglobin (Hb) bis-tetramers (bis-tetramers of hemoglobin that are prepared using CuAAC chemistry [BT-Hb] and bis-tetramers of hemoglobin that are specifically acetylated and prepared using CuAAC chemistry [BT-acHb]) can be reliably produced by a bio-orthogonal cyclo-addition approach. We considered that an HBOC derived from chemical coupling of two Hbs would be sufficiently large to avoid NO scavenging and related side effects. The ability of intravenously infused BT-Hb and BT-acHb to remain in the circulation without causing hypertension were determined in wild-type (WT) and diabetic (db/db) mouse models.
In WT mice, the coupled oxygen-carrying proteins retained their function over several hours after administration. No significant changes in systolic blood pressure from baseline were observed after intravenous infusion of BT-Hb or BT-acHb in awake WT and db/db mice. In contrast, infusion of native Hb or cross-linked Hb tetramers in both animal models induced systemic hypertension.
The results of this study indicate that bis-tetrameric HBOCs derived from the bio-orthogonal cyclo-addition process are likely to overcome clinical issues that arise from NO scavenging by Hb derivatives.
基于血红蛋白的氧载体（HBOCs）是输血中红细胞的潜在替代品。使用早期版本HBOCs的临床试验发现了一些不良反应，这些反应似乎是由于血管舒张剂一氧化氮（NO）的清除所致。先前的报道表明，尺寸增大的HBOCs可能会避开血管系统中富含NO的区域，因此不会引起血管收缩和高血压。
血红蛋白（Hb）双四聚体（使用铜催化的叠氮化物-炔烃环加成反应（CuAAC）化学方法制备的血红蛋白双四聚体[BT-Hb]以及经过特定乙酰化并使用CuAAC化学方法制备的血红蛋白双四聚体[BT-acHb]）可以通过生物正交环加成方法可靠地生产。我们认为，由两个Hb化学偶联得到的HBOC将足够大，以避免NO清除及相关副作用。在野生型（WT）和糖尿病（db/db）小鼠模型中，测定了静脉注射BT-Hb和BT-acHb后在循环中留存且不引起高血压的能力。
在WT小鼠中，给药后数小时内，偶联的载氧蛋白仍保持其功能。在清醒的WT和db/db小鼠中静脉注射BT-Hb或BT-acHb后，收缩压与基线相比无显著变化。相比之下，在两种动物模型中输注天然Hb或交联Hb四聚体均会诱发全身性高血压。
本研究结果表明，通过生物正交环加成过程得到的双四聚体HBOCs可能会克服由Hb衍生物清除NO所引发的临床问题。
