Mixtures of tense and relaxed state polymerized human hemoglobin regulate oxygen affinity and tissue construct oxygenation.

Donald Andrew Belcher,Uddyalok Banerjee,Christopher Michael Baehr,Pedro Cabrales,Andre Francis Palmer,François Berthiaume,Kristopher Emil Richardson

doi:10.1371/journal.pone.0185988

Donald Andrew Belcher, Uddyalok Banerjee + Show 5 more

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https://doi.org/10.1371/journal.pone.0185988

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Abstract

Pure tense (T) and relaxed (R) quaternary state polymerized human hemoglobins (PolyhHbs) were synthesized and their biophysical properties characterized, along with mixtures of T- and R-state PolyhHbs. It was observed that the oxygen affinity of PolyhHb mixtures varied linearly with T-state mole fraction. Computational analysis of PolyhHb facilitated oxygenation of a single fiber in a hepatic hollow fiber (HF) bioreactor was performed to evaluate the oxygenation potential of T- and R-state PolyhHb mixtures. PolyhHb mixtures with T-state mole fractions greater than 50% resulted in hypoxic and hyperoxic zones occupying less than 5% of the total extra capillary space (ECS). Under these conditions, the ratio of the pericentral volume to the perivenous volume in the ECS doubled as the T-state mole fraction increased from 50 to 100%. These results show the effect of varying the T/R-state PolyhHb mole fraction on oxygenation of tissue-engineered constructs and their potential to oxygenate tissues.

Highlights

A major challenge in tissue engineering is provision of physiologically relevant oxygenation to cells cultured within tissue-engineered constructs [1]
To assess the ability of the polymerized human Hb (PolyhHb) mixtures to oxygenate tissue engineered constructs, we developed a computational model of a single hollow fiber (HF) in a HF bioreactor housing hepatocytes, where the inlet partial pressure of O2, mixture fraction, and total PolyhHb concentration were varied to assess oxygenation within the device
It is necessary to measure the biophysical properties of 35:1 T-state PolyhHb, 30:1 R-state PolyhHb, and various mixtures of these two types of hemoglobin facilitate tissue construct oxygenation carriers (HBOCs) to evaluate their O2 transport potential in transfusion and tissue engineering applications

Summary

Introduction

A major challenge in tissue engineering is provision of physiologically relevant oxygenation to cells cultured within tissue-engineered constructs [1]. RBC perfusion may be plagued with issues ranging from short ex vivo storage shelflife (i.e. 42 days) [3], limited supply [4,5], risk of transmission of unidentified pathogens [6], and RBC hemolysis [7]. In light of these challenges, hemoglobin (Hb)-based oxygen (O2).

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