The role of facilitated diffusion in oxygen transport by cell-free hemoglobins: implications for the design of hemoglobin-based oxygen carriers

McCarthy, Michael; Vandegriff, Kim D.; Winslow, Robert M.

doi:10.1016/s0301-4622(01)00194-6

Cited by 157 publications

(160 citation statements)

References 39 publications

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“…The regressed P 50 and cooperativity coefficient of human Hb is 12.83 torr and 2.96, respectively. Compared to values reported in the literature [29], the P 50 for purified hHb is similar. Hu et al [10] reported a P 50 of 14 torr and a cooperativity of 2.8 for hHb, whereas [29] reported a P 50 of 15.1 torr and a cooperativity of 2.97 for hHb.…”

Section: Purification Of Hbsupporting

confidence: 71%

“…Compared to values reported in the literature [29], the P 50 for purified hHb is similar. Hu et al [10] reported a P 50 of 14 torr and a cooperativity of 2.8 for hHb, whereas [29] reported a P 50 of 15.1 torr and a cooperativity of 2.97 for hHb. The difference between these published values and the values in this work are easily explained in terms of the different buffer conditions used for measuring the oxygen binding equilibria.…”

Section: Purification Of Hbsupporting

confidence: 71%

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Preparation of ultrapure bovine and human hemoglobin by anion exchange chromatography

Sun

Palmer²

2008

Journal of Chromatography B

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Bovine and human hemoglobin (Hb) form the basis for many different types of Hb-based O 2 carriers (HBOCs) ranging from chemically modified Hbs to particle encapsulated Hbs. Hence, the development of a facile purification method for preparing ultrapure Hb is essential for the reliable synthesis and formulation of HBOCs. In this work, we describe a simple process for purifying ultrapure solutions of bovine and human Hb. Bovine and human red blood cells (RBCs) were lyzed, and Hb was purified from the cell lysate by anion exchange chromatography. The initial purity of Hb fractions was analyzed by SDS-PAGE. Pure Hb fractions (corresponding to a single band on the SDS-PAGE gel) were pooled together and the overall purity and identity assessed by LC-MS. LC-MS analysis yielded two peaks corresponding to the calculated theoretical molecular weight of the α and β chains of Hb. The activity of HPLC pure Hb was assessed by measuring its oxygen affinity, cooperativity and methemoglobin level. These measures of activity were comparable to values in the literature. Taken together, our results demonstrate that ultrapure Hb (electrophoresis and HPLC pure) can be easily prepared via anion exchange chromatography. In general, this method can be more broadly applied to purify hemoglobin from any source of RBC. This work is significant, since it outlines a simple method for generating ultrapure Hb for synthesis and/or formulation of HBOCs.

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Section: Purification Of Hbsupporting

confidence: 71%

Section: Purification Of Hbsupporting

confidence: 71%

Preparation of ultrapure bovine and human hemoglobin by anion exchange chromatography

Sun

Palmer²

2008

Journal of Chromatography B

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“…The p50s of a PEG-conjugated Hb product (MP4), 5 mmHg, and a polymerized bovine Hb product (PolyBvHb), 54 mmHg, represent this range. An extensive series of in vivo experiments with HBOCs of varied p50s have shown increased efficacy for HBOCs with high O 2 affinities [3][4][5]; this data has led to the theory of autoregulatory vasoconstriction by arteriolar over supply of O 2 , which we discuss elsewhere [6,7]. More recently, there has been a general agreement that increasing the molecular size of Hb is advantageous; the estimated molecular weights of both MP4 (~95 kDa) [8] and PolyBvHb (~200 kDa) [9] are larger than unmodified or intramolecularly cross-linked Hbs (64 kDa) [10].…”

Section: Introductionmentioning

confidence: 96%

“…These models are well accepted, and have been extensively validated by gasexchange experiments in arteriolar-sized conduits [14,16,17]. Such models provide O 2 transport behavior to be quantified under dynamic flowing conditions in the absence of biological flow regulation, and these previous O 2 transport experiments [7,14,16,17] and simulations [13][14][15] considered only small values of extra-luminal resistance. To increase the relevance of this type of mathematical modeling, we have applied additional extra-luminal boundary conditions to in vitro studies.…”

Section: Introductionmentioning

confidence: 99%

A quantitative framework for the design of acellular hemoglobins as blood substitutes: Implications of dynamic flow conditions

Cole

Vandegriff²,

Szeri

et al. 2007

Biophysical Chemistry

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The delivery of oxygen to tissue by cell-free carriers eliminates intraluminal barriers associated with red blood cells. This is important in arterioles, since arteriolar tone controls capillary perfusion. We describe a mathematical model for O 2 transport by hemoglobin solutions and red blood cells flowing through arteriolar-sized tubes to optimize values of p50, Hill number, hemoglobin molecular diffusivity and concentration. Oxygen release is evaluated by including an extra-luminal resistance term to reflect tissue oxygen consumption. For low consumption (i.e., high resistance to O 2 release) a hemoglobin solution with p50=15 mmHg, Hill n=1, D HBO2 =3×10 −7 cm 2 /s delivers O 2 at a rate similar to that of red blood cells. For high consumption, the p50 must be decreased to 5 mmHg. The model predicts that regardless of size, hemoglobin solutions with higher p50 will present excess O 2 to arteriolar walls. Oversupply of O 2 to arteriolar walls may cause constriction and paradoxically reduced capillary perfusion.

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“…In contrast, cell-free Hb increases the solubility of oxygen in the plasma and decreases the resistance for oxygen diffusion as long as exchange of oxygen between the HBOC and dissolved oxygen is constantly occurring [23,25,36]. Thus, the movement of HBOCs within plasma facilitates the diffusion of oxygen from the red blood cell to the endothelium [6,37,38]. Although HBOCs with a P 50 of 3 Torr (and low off-rate constant kinetics) exchange less oxygen per unit time with plasma than do those with high P 50 , the amount of Hb in the plasma necessary to facilitate oxygen transport from the red cell to the endothelium may be relatively small, especially if transit times across the microcirculatory exchange site are of long duration, as expected during ischemia.…”

Section: Interpretation Of Results With Hboc Possessing Different Oxymentioning

confidence: 99%

Insensitivity of cerebral oxygen transport to oxygen affinity of hemoglobin-based oxygen carriers

Koehler

Fronticelli

Bucci

2008

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

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The cerebrovascular effects of exchange transfusion of various cell-free hemoglobins that possess different oxygen affinities are reviewed. Reducing hematocrit by transfusion of a non-oxygencarrying solution dilates pial arterioles on the brain surface and increases cerebral blood flow to maintain a constant bulk oxygen transport to the brain. In contrast, transfusion of hemoglobins with P 50 of 4-34 Torr causes constriction of pial arterioles that offsets the decrease in blood viscosity to maintain cerebral blood flow and oxygen transport. The autoregulatory constriction is dependent on synthesis of 20-HETE from arachidonic acid. This oxygen-dependent reaction is apparently enhanced by facilitated oxygen diffusion from the red cell to the endothelium arising from increased plasma oxygen solubility in the presence of low or high-affinity hemoglobin. Exchange transfusion of recombinant hemoglobin polymers with P 50 of 3 and 18 Torr reduces infarct volume from experimental stroke. Cell-free hemoglobins do not require a P 50 as high as red blood cell hemoglobin to facilitate oxygen delivery.

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The role of facilitated diffusion in oxygen transport by cell-free hemoglobins: implications for the design of hemoglobin-based oxygen carriers

Cited by 157 publications

References 39 publications

Preparation of ultrapure bovine and human hemoglobin by anion exchange chromatography

Preparation of ultrapure bovine and human hemoglobin by anion exchange chromatography

A quantitative framework for the design of acellular hemoglobins as blood substitutes: Implications of dynamic flow conditions

Insensitivity of cerebral oxygen transport to oxygen affinity of hemoglobin-based oxygen carriers

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