Laboratory of Biochemistry and Vascular Biology, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
Biomaterials. 2010 May;31(13):3723-35. doi: 10.1016/j.biomaterials.2010.01.072. Epub 2010 Feb 10.
Hemoglobin-based oxygen carriers (HBOC) are currently being developed as red blood cell (RBC) substitutes for use in transfusion medicine. Despite significant commercial development, late stage clinical results of polymerized hemoglobin (PolyHb) solutions hamper development. We synthesized two types of PolyHbs with ultrahigh molecular weights: tense (T) state PolyHb (M(W)=16.59 MDa and P(50)=41 mmHg) and relaxed (R) state PolyHb (M(W)=26.33 MDa and P(50)=0.66 mmHg). By maintaining Hb in either the T- or R-state during the polymerization reaction, we were able to synthesize ultrahigh molecular weight PolyHbs in distinct quaternary states with no tetrameric Hb, high viscosity, low colloid osmotic pressure and the ability to maintain O(2) dissociation, CO association and NO dioxygenation reactions. The PolyHbs elicited some in vitro RBC aggregation that was less than 6% dextran (500 kDa) but more than 5% human serum albumin. In vitro, T-state PolybHb autoxidized faster than R-state PolybHb as expected from previously reported studies, conversely, when administered to guinea pigs as a 20% exchange transfusion, R-state PolybHb oxidized faster and to a greater extent than T-state PolybHb, suggesting a more complex oxidative processes in vivo. Our findings also demonstrate that T-state PolybHb exhibited a longer circulating half-life, slower clearance and longer systemic exposure time compared to R-state PolybHb.
血红蛋白基氧载体（HBOC）目前正在被开发为用于输血医学的红细胞（RBC）替代品。尽管已经进行了大量的商业开发，但聚合血红蛋白（PolyHb）溶液的后期临床结果阻碍了其发展。我们合成了两种超高分子量的 PolyHb：紧张（T）态 PolyHb（M(W)=16.59 MDa 和 P(50)=41 mmHg）和松弛（R）态 PolyHb（M(W)=26.33 MDa 和 P(50)=0.66 mmHg）。通过在聚合反应过程中使血红蛋白保持在 T-或 R-状态，我们能够在不同的四级状态下合成超高分子量的 PolyHb，其中没有四聚体血红蛋白、高粘度、低胶体渗透压，并且能够维持 O(2)的解离、CO 的结合和 NO 的双氧键化反应。PolyHb 引起了一些体外 RBC 聚集，其聚集程度小于 6%的葡聚糖（500 kDa）但大于 5%的人血清白蛋白。在体外，T-态 PolyHb 的自氧化速度比 R-态 PolyHb 快，这与之前报道的研究结果一致，相反，当作为 20%的交换输血给予豚鼠时，R-态 PolyHb 的氧化速度更快，程度更大，表明体内存在更复杂的氧化过程。我们的研究结果还表明，与 R-态 PolyHb 相比，T-态 PolyHb 表现出更长的循环半衰期、更慢的清除率和更长的全身暴露时间。
