Hemoglobin solutions

Abstract

Today, we are aware of the effects of the first generation of blood substitutes. Further research is ongoing into newer solutions. One area of interest is the development of new molecular structures to decrease nitric oxide binding, thus minimizing any adverse events and maximizing potential benefits. Nevertheless, possible adverse effects need to be carefully evaluated before these agents can be widely administered.

Artificial oxygen carriers as a possible alternative to red cells in clinical practice

“…21 The hemoglobin used for manufacturing HBOCs originates from out-of-date human red cells or from bovine blood, or is genetically engineered. 2,5,7,17 Once the hemoglobin moiety has been removed from the protective environment of the RBC membrane, low concentrations of 2,3-diphosphoglycerate (2,3-DPG) are present. These cause the oxyhemoglobin dissociation curve to left-shift (decrease in P 50 ).…”

“…7 Based on techniques for improving molecular stability, four groups of hemoglobin solution are currently available: surface-modified hemoglobin, intramolecular cross-linked hemoglobin, polymerized hemoglobin and liposome-encapsulated hemoglobin. 5 These products do not have antigenic features and do not require compatibility testing. 4 The HBOCs under development all have vascular half-lives in the range of 18 to 24 hours, which is adequate for most acute care applications.…”

“…The hemoglobin tetramers dissociate into their component αβ dimers, which undergo rapid elimination by the kidneys, from which renal toxicity may result. 5 Purified hemoglobin molecules are chemically modified to increase their stability and to modulate oxygen affinity. 6 These chemical modifications include intramolecular cross-linking, polymerization using glutaraldehyde or o-raffinose, conjugation of polyethylene glycol, insertion of 2,3-DPG analogues or embedding of hemoglobin molecules into phospholipid vesicles.…”

“…3 The ideal characteristics for blood substitutes are: nonantigenic properties; similarity to natural hemoglobin in terms of oxygen and carbon dioxide transport and delivery; absence of renal toxicity; stability at room temperature; sufficient half-life in circulation; long shelf life; ease of use; no overloading of the reticuloendothelial system; and low cost. [4][5][6] The development of modified hemoglobin solutions in the 1980s was an improvement, in which the products showed stability and fewer side effects. 5 Arterial oxygen carriers based on perfluorocarbons or hemoglobin-based oxygen carriers (HBOCs) are alternatives to allogenic red blood cells (RBCs).…”

“…[4][5][6] The development of modified hemoglobin solutions in the 1980s was an improvement, in which the products showed stability and fewer side effects. 5 Arterial oxygen carriers based on perfluorocarbons or hemoglobin-based oxygen carriers (HBOCs) are alternatives to allogenic red blood cells (RBCs). 7 …”