Influence of Molecular Structure on O2-Binding Properties and Blood Circulation of Hemoglobin‒Albumin Clusters

Abstract

A hemoglobin wrapped covalently by three human serum albumins, a Hb-HSA3 cluster, is an artificial O2-carrier with the potential to function as a red blood cell substitute. This paper describes the synthesis and O2-binding properties of new hemoglobin‒albumin clusters (i) bearing four HSA units at the periphery (Hb-HSA4, large-size variant) and (ii) containing an intramolecularly crosslinked Hb in the center (XLHb-HSA3, high O2-affinity variant). Dynamic light scattering measurements revealed that the Hb-HSA4 diameter is greater than that of either Hb-HSA3 or XLHb-HSA3. The XLHb-HSA3 showed moderately high O2-affinity compared to the others because of the chemical linkage between the Cys-93(β) residues in Hb. Furthermore, the blood circulation behavior of 125I-labeled clusters was investigated by assay of blood retention and tissue distribution after intravenous administration into anesthetized rats. The XLHb-HSA3 was metabolized faster than Hb-HSA3 and Hb-HSA4. Results suggest that the molecular structure of the protein cluster is a factor that can influence in vivo circulation behavior.

Comparison of the Pharmacokinetic Properties of Hemoglobin-Based Oxygen Carriers

“…HemoAct showed good blood compatibility in vitro, and it induced neither hypertension nor toxicity in vivo [89]. Komatsu and colleagues prepared three types of Hb-HSA clusters, Hb-HSA 3 (Hb was enclosed by three HSA molecules), Hb-HSA 4 (Hb was wrapped by four has molecules), and XLHb-HSA 3 (intramolecularly crosslinked Hb was enclosed by three HSA molecules), and compared their pharmacokinetic properties [89,90]. The half-lives of all types of Hb-HSA clusters were more than 20-times and 1.5 times longer than that of Hb and has, respecctively.…”

Artificial Blood for Dogs

“…demonstrated that the large-size proteins are cleared with predominant uptake by the liver49. Furthermore, we found that Hb-HSA 3 cluster were metabolized in the body and excreted into urine, which is the same excretion pathway of HSA48. The Hb-rCSA 3 cluster is likely to show high hepatic distribution after administration into dogs and to be excreted into urine.…”

“…We reported previously the tissue distribution and metabolism of Hb-HSA 3 cluster in rats3148. The cluster and HSA were similarly distributed in the major organs at 1 h after injection.…”

Protein-Cross-Linked Hydrogels with Tailored Swelling and Bioactivity Performance: A Comparative Study

“…Synthesis of Protein-Based Hydrogel. As reported, protein does not contain many free thiol groups in its natural form, for example, only 2 thiol groups are accessible on the Hb surface for functionalization, 27 and each BSA molecule carries only one free thiol group. 28 Although the 2 thiol groups are active for Hb hydrogel formation, the resulting gel disintegrated very quickly due to the low cross-link density (Figure S1 of the Supporting Information).…”