Hemoglobin-based oxygen carriers: from mechanisms of toxicity and clearance to rational drug design

doi:10.1016/j.molmed.2010.07.006

Trends in Molecular Medicine

Volume 16, Issue 10, October 2010, Pages 447-457

https://doi.org/10.1016/j.molmed.2010.07.006 Get rights and content

Hemoglobin-based oxygen carriers (HBOCs) have been developed to support blood oxygen transport capacity during hemorrhagic shock, hemolysis and ischemic insult. Existing product candidates have demonstrated considerable efficacy in experimental animal models and in clinical trial subjects; however, severe adverse safety signals that appeared in recent phase II and phase III clinical trials involving certain HBOCs have in part hindered further development and licensing. Emerging insights into hemoglobin (Hb) toxicity as well as physiologic Hb scavengers such as haptoglobin and CD163 that are capable of detoxifying extracellular Hb in vivo suggest that alternative product candidates could be designed. Together with novel animal models and biomarkers tailored to monitor the effects of extracellular Hb, a new generation of HBOCs can be envisioned.

Section snippets

The current status of hemoglobin-based oxygen carriers (HBOCs)

HBOCs were developed as alternatives to blood transfusion, for use as oxygen-bridging agents and as oxygen therapeutics in ischemic conditions. Initial developmental efforts focused on preparations of native hemoglobin (Hb) from red blood cells (RBCs) as a universally transfusible oxygen carrying solution (see Glossary) [1]. However, subjects treated with these Hb preparations experienced hypertension and acute renal failure. Several years later it was realized that Hb could readily dimerize

Systemic hypertension

HBOCs are often described as problematic owing to vasoconstriction (increased systemic vascular resistance, SVR) and hypertension post-administration. The most accepted hypothesis suggests that Hb-induced hypertension is primarily caused by the reactions of nitric oxide (NO) with both oxy- and deoxyhemoglobin 6, 7. The depletion of NO impairs vasodilation and promotes vasoconstriction via reduction of cyclic GMP levels in vascular smooth muscle cells 8, 9. This physiologic response causes a

Antioxidant status of preclinical models

Animal species used for the prediction of human safety responses are typically chosen based on the likelihood that their pharmacokinetic, pharmacodynamic and certain physiologic parameters are related to humans. Lesser-studied areas with regard to HBOCs are the vasculature and tissue compartment parenchyma oxidative stress. The initiation of oxidative stress leading to toxicity might be acute or long-term and is probably disease-state driven. Circulating plasma as well as tissue antioxidant

Sensitive and specific markers of oxidative damage

The oxidation of extracellular Hb or HBOC products to methemoglobin (ferric, Fe³⁺), ferryl heme intermediate (Fe⁴⁺), hemichromes and free heme or iron can initiate or propagate oxidative damage to lipids, nucleic acids and proteins [35]. In vivo oxidative events could be evaluated by measuring the end products of oxidative damage. In recent years, biomarkers such as 4-hydroxy-2-nonenal (4-HNE) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) have gained wide acceptance as reliable and sensitive indices

Drug design strategies toward alternative HBOCs

Several innovative strategies have been proposed over the past few years to overcome the hurdles of extracellular Hb toxicity and to increase the safety of HBOCs. For example, attempts at attenuation of HBOC-induced hypertension have focused on means to increase NO bioavailability and to normalize vasoconstriction by either limiting NO–heme pocket interactions 6, 7, 64 or using pharmacologic methods of NO supplementation (e.g. through NO inhalation) 65, 66, 67. DeoxyHb has an intrinsic nitrite

Soluble and cell-based Hb scavenger pathways

The mammalian Hb scavenger system is a multicomponent pathway comprising several soluble proteins and receptors that protect against systemic Hb toxicity until heme is degraded into non-toxic metabolites by the heme oxygenases 71, 72 (Figure 3). The most extensively studied Hb scavengers are haptoglobin (Hp) and the Hb:Hp scavenger receptor CD163. Other plasma proteins such as hemopexin, α₁-microglobulin and albumin have a role as a second line defense to detoxify free heme 73, 74. Although the

Interaction of existing HBOC with Hb scavengers

Detailed knowledge of molecularly defined clearance pathways is essential for rational drug development as it allows for the prediction and eventually the modification of plasma half-life, duration of activity and potential drug interactions. In the case of HBOCs, knowledge of clearance and degradation mechanisms is astonishingly limited. Potential HBOC products are designed to limit renal clearance (e.g. to reduce toxic renal tissue exposure and to prolong half-life). Recently, HBOCs with

Concluding remarks

Controlled clinical trials on HBOCs have provided the most in depth information on the potentially harmful effects of extracellular Hb [5]. A causative role for HBOC-mediated vascular dysfunction characterized by hypertension, inflammation and oxidative stress has been proposed but awaits confirmation. It seems, therefore, that a more comprehensive understanding of Hb toxicity is needed to inform HBOC development initiatives.

Specifically, it will be important to reconcile the different

Acknowledgements

This work was supported a FDA Critical Path Initiative grant to (P.W.B and F.D). A Swiss National Science Foundation grant (# 31-120658) and Fonds für Akademische Nachwuchförderung (FAN) funding (University of Zurich) to (D.J.S.).

Glossary

F₂-isoprostane: is a prostaglandin-like peroxidation product of arachidonic acid with potent biologic activities.
Hemoglobin-based oxygen carriers (HBOCs): are a group of biologic therapeutics designed to support the oxygen carrier capacity of RBCs. HBOCs are usually derived from human or animal source Hb (i.e. outdated blood transfusion units). Diverse chemical modifications such as covalent Hb subunit crosslinking, polymerization and/or surface decoration (i.e. PEGylation) should optimize ligand

References (100)

J.S. Olson
No scavenging and the hypertensive effect of hemoglobin-based blood substitutes
Free Radic. Biol. Med.
(2004)
M.R. McCarthy
The role of facilitated diffusion in oxygen transport by cell-free hemoglobins: implications for the design of hemoglobin-based oxygen carriers
Biophys. Chem.
(2001)
R.J. Rohlfs
Arterial blood pressure responses to cell-free hemoglobin solutions and the reaction with nitric oxide
J. Biol. Chem.
(1998)
E. Schroder et al.
Hydrogen peroxide as an endogenous mediator and exogenous tool in cardiovascular research: issues and considerations
Curr. Opin. Pharmacol.
(2008)
K.P. Moore
A causative role for redox cycling of myoglobin and its inhibition by alkalinization in the pathogenesis and treatment of rhabdomyolysis-induced renal failure
J. Biol. Chem.
(1998)
C.C. Winterbourn
Biological reactivity and biomarkers of the neutrophil oxidant, hypochlorous acid
Toxicology
(2002)
C.C. Winterbourn et al.
Biomarkers of myeloperoxidase-derived hypochlorous acid
Free Radic. Biol. Med.
(2000)
A. Nandi
Evolutionary significance of vitamin C biosynthesis in terrestrial vertebrates
Free Radic. Biol. Med.
(1997)
C.E. Cooper
Peroxidase activity of hemoglobin towards ascorbate and urate: a synergistic protective strategy against toxicity of hemoglobin-based oxygen carriers (HBOC)
Biochim. Biophys. Acta
(2008)
D. Su
Human erythrocyte membranes contain a cytochrome b561 that may be involved in extracellular ascorbate recycling
J. Biol. Chem.
(2006)

F. D’Agnillo et al.

Redox cycling of diaspirin cross-linked hemoglobin induces G2/M arrest and apoptosis in cultured endothelial cells

Blood

(2001)

F. D’Agnillo et al.

A role for the myoglobin redox cycle in the induction of endothelial cell apoptosis

Free Radic. Biol. Med.

(2002)

W. Kaca

Hemoglobin, a newly recognized lipopolysaccharide (LPS)-binding protein that enhances LPS biological activity

J. Biol. Chem.

(1994)

R.J. Schaur

Basic aspects of the biochemical reactivity of 4-hydroxynonenal

Mol. Aspects Med.

(2003)

Y. Dou

Myoglobin as a model system for designing heme protein based blood substitutes

Biophys. Chem.

(2002)

B. Yu

Hemoglobin-based red blood cell substitutes and nitric oxide

Trends Cardiovasc. Med.

(2009)

M.T. Gladwin et al.

The functional nitrite reductase activity of the heme-globins

Blood

(2008)

B.J. Reeder

Tyrosine residues as redox cofactors in human hemoglobin: implications for engineering nontoxic blood substitutes

J. Biol. Chem.

(2008)

B.J. Reeder

Tyrosine as a redox-active center in electron transfer to ferryl heme in globins

Free Radic. Biol. Med.

(2008)

L.J. Deterding

Identification of free radicals on hemoglobin from its self-peroxidation using mass spectrometry and immuno-spin trapping: observation of a histidinyl radical

J. Biol. Chem.

(2004)

M.J. Nielsen et al.

Receptor targeting of hemoglobin mediated by the haptoglobins: roles beyond heme scavenging

Blood

(2009)

F. Vinchi

Hemopexin prevents endothelial damage and liver congestion in a mouse model of heme overload

Am. J. Pathol.

(2008)

E. Tolosano

Enhanced splenomegaly and severe liver inflammation in haptoglobin/hemopexin double-null mice after acute hemolysis

Blood

(2002)

J.C. Wejman

Structure and assembly of haptoglobin polymers by electron microscopy

J. Mol. Biol.

(1984)

J.C. Wejman

Structure of haptoglobin and the haptoglobin-hemoglobin complex by electron microscopy

J. Mol. Biol.

(1984)

P.W. Buehler

Haptoglobin preserves the CD163 hemoglobin scavenger pathway by shielding hemoglobin from peroxidative modification

Blood

(2009)

A. Kapralov

Peroxidase activity of hemoglobin-haptoglobin complexes: covalent aggregation and oxidative stress in plasma and macrophages

J. Biol. Chem.

(2009)

S.K. Lim

Increased susceptibility in Hp knockout mice during acute hemolysis

Blood

(1998)

R.L. Nagel et al.

The binding of hemoglobin to haptoglobin and its relation to subunit dissociation of hemoglobin

J. Biol. Chem.

(1971)

M. Melamed-Frank

Structure-function analysis of the antioxidant properties of haptoglobin

Blood

(2001)

D.J. Schaer

CD163 is the macrophage scavenger receptor for native and chemically modified hemoglobins in the absence of haptoglobin

Blood

(2006)

J.J. Boyle

Coronary intraplaque hemorrhage evokes a novel atheroprotective macrophage phenotype

Am. J. Pathol.

(2009)

S.S. Damle

Hemoglobin-based oxygen carrier induces heme oxygenase-1 in the heart and lung but not brain

J. Am. Coll. Surg.

(2009)

W.R. Amberson

Mammalian life without red blood corpuscles

Science

(1933)

H.F. Bunn

The renal handling of hemoglobin. I. Glomerular filtration

J. Exp. Med.

(1969)

J.G. Riess

Oxygen carriers (“blood substitutes”) – raison d’etre, chemistry, and some physiology

Chem. Rev.

(2001)

C. Natanson

Cell-free hemoglobin-based blood substitutes and risk of myocardial infarction and death: a meta-analysis

J. Am. Med. Assoc.

(2008)

T.A. Silverman et al.

Hemoglobin-based oxygen carriers: current status and future directions

Anesthesiology

(2009)

D.H. Doherty

Rate of reaction with nitric oxide determines the hypertensive effect of cell-free hemoglobin

Nat. Biotechnol.

(1998)

R.F. Furchgott

Endothelial cells as mediators of vasodilation of arteries

J. Cardiovasc. Pharmacol.

(1984)

R.F. Furchgott et al.

The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine

Nature

(1980)

P.W. Buehler

Effects of endogenous ascorbate on oxidation, oxygenation and toxicokinetics of cell-free modified hemoglobin after exchange transfusion in rat and guinea pig

J. Pharmacol. Exp. Ther.

(2007)

B. Yu

Endothelial dysfunction enhances vasoconstriction due to scavenging of nitric oxide by a hemoglobin-based oxygen carrier

Anesthesiology

(2010)

Ballermann, B.J. et al. (1998) Shear stress and the endothelium. Kidney Int. 54 (Suppl. 67),...

S.R. Fischer

Plasma volume expansion with solutions of hemoglobin, albumin, and Ringer lactate in sheep

Am. J. Physiol.

(1999)

A. Gulati

Role of endothelin in the cardiovascular effects of diaspirin crosslinked and stroma reduced hemoglobin

Crit. Care Med.

(1996)

A. Koller

Role of shear stress and endothelial prostaglandins in flow- and viscosity-induced dilation of arterioles in vitro

Circ. Res.

(1993)

J. Simoni

Evaluation of angiotensin converting enzyme (ACE)-like activity of acellular hemoglobin

Artif. Cells Blood Substit. Immobil. Biotechnol.

(2007)

H.W. Farber et al.

Pulmonary arterial hypertension

N. Engl. J. Med.

(2004)

B. Yu

Prevention of the pulmonary vasoconstrictor effects of HBOC-201 in awake lambs by continuously breathing nitric oxide

Anesthesiology

(2009)

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Trends in Molecular Medicine

ReviewHemoglobin-based oxygen carriers: from mechanisms of toxicity and clearance to rational drug design

Section snippets

The current status of hemoglobin-based oxygen carriers (HBOCs)

Systemic hypertension

Antioxidant status of preclinical models

Sensitive and specific markers of oxidative damage

Drug design strategies toward alternative HBOCs

Soluble and cell-based Hb scavenger pathways

Interaction of existing HBOC with Hb scavengers

Concluding remarks

Acknowledgements

Glossary

Free Radic. Biol. Med.

Biophys. Chem.

J. Biol. Chem.

Curr. Opin. Pharmacol.

J. Biol. Chem.

Toxicology

Free Radic. Biol. Med.

Free Radic. Biol. Med.

Biochim. Biophys. Acta

J. Biol. Chem.

Blood

Free Radic. Biol. Med.

J. Biol. Chem.

Mol. Aspects Med.

Biophys. Chem.

Trends Cardiovasc. Med.

Blood

J. Biol. Chem.

Free Radic. Biol. Med.

J. Biol. Chem.

Blood

Am. J. Pathol.

Blood

J. Mol. Biol.

J. Mol. Biol.

Blood

J. Biol. Chem.

Blood

J. Biol. Chem.

Blood

Blood

Am. J. Pathol.

J. Am. Coll. Surg.

Mammalian life without red blood corpuscles

Science

The renal handling of hemoglobin. I. Glomerular filtration

J. Exp. Med.

Oxygen carriers (“blood substitutes”) – raison d’etre, chemistry, and some physiology

Chem. Rev.

Cell-free hemoglobin-based blood substitutes and risk of myocardial infarction and death: a meta-analysis

J. Am. Med. Assoc.

Hemoglobin-based oxygen carriers: current status and future directions

Anesthesiology

Rate of reaction with nitric oxide determines the hypertensive effect of cell-free hemoglobin

Nat. Biotechnol.

Endothelial cells as mediators of vasodilation of arteries

J. Cardiovasc. Pharmacol.

The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine

Nature

Effects of endogenous ascorbate on oxidation, oxygenation and toxicokinetics of cell-free modified hemoglobin after exchange transfusion in rat and guinea pig

J. Pharmacol. Exp. Ther.

Endothelial dysfunction enhances vasoconstriction due to scavenging of nitric oxide by a hemoglobin-based oxygen carrier

Anesthesiology

Plasma volume expansion with solutions of hemoglobin, albumin, and Ringer lactate in sheep

Am. J. Physiol.

Role of endothelin in the cardiovascular effects of diaspirin crosslinked and stroma reduced hemoglobin

Crit. Care Med.

Role of shear stress and endothelial prostaglandins in flow- and viscosity-induced dilation of arterioles in vitro

Circ. Res.

Evaluation of angiotensin converting enzyme (ACE)-like activity of acellular hemoglobin

Artif. Cells Blood Substit. Immobil. Biotechnol.

Pulmonary arterial hypertension

N. Engl. J. Med.

Prevention of the pulmonary vasoconstrictor effects of HBOC-201 in awake lambs by continuously breathing nitric oxide

Anesthesiology

Review
Hemoglobin-based oxygen carriers: from mechanisms of toxicity and clearance to rational drug design