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Full text release has been delayed at the author's request until December 18, 2024

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Synthesis of High Molecular Weight Polymerized Human Hemoglobins and Evaluation of Vascular Extravasation in a Microfluidic Model

Wolfe, Savannah R
http://orcid.org/0000-0001-9806-9492
http://rave.ohiolink.edu/etdc/view?acc_num=osu166746995103041

Abstract Details

2022, Doctor of Philosophy, Ohio State University, Chemical Engineering.
Despite the underlying role of hypoxia and oxidative stress in vascular and inflammatory diseases, little is understood about its role in early disease progression and no therapeutics exist to combat it. Hypoxia is suspected to disrupt the function of the endothelium, the inner lining of cells in all vessels which is responsible for regulating exchange between nutrients and waste metabolites in the blood stream and tissues. Due to the vital and far-reaching functions of the endothelium in modulating vascular tone, inflammatory pathways, and the formation of new vessels, endothelial dysfunction often precedes and can be propagated in vascular disease. Consequently, studying the relationship between hypoxia and endothelial dysfunction is an area of great interest in identifying potential therapeutic targets for early intervention. A pathophysiology of particular interest in this work is preeclampsia (PE), a pregnancy disorder which is poorly understood. In PE, early vascular dysregulation leads to later appearance of clinical symptoms. Hypoxia is intimately involved in the progression of PE and its potentially devastating effects on fetal development. No therapeutic interventions currently exist for PE. As such, PE is an excellent environment in which to investigate whether oxygen (O2) modulation can rescue vascular dysregulation. One promising candidate for therapeutically alleviating hypoxia associated with the vascular disease state is hemoglobin-based O2 carriers (HBOCs). However, commercially available HBOCs contain low molecular weight (LMW) species which induce cytotoxicity due to extravasation. This work focused on synthesizing and characterizing high molecular weight (HMW) polymerized human hemoglobins (hHb)(PolyhHbs) in order to achieve a therapeutic O2 carrier with an improved safety profile. To this end, a tunable platform replicating human microvasculature was developed and used to evaluate HMW PolyhHb’s potential for extravasation and endothelial interaction in vivo. First, HMW PolyhHbs were synthesized, and an optimized purification scheme enabled the removal of most LMW species and native cell-free hHb (>90%) which were responsible for adverse cytotoxic events in previous clinical trials. This endeavor built upon the previous work completed in this lab which enabled a high level of control over PolyhHb MW and O2-carrying properties. These HMW PolyhHbs were fluorescently labeled so that they could be easily visualized and tracked in a microfluidic model. The PolyhHbs were then integrated into an on-chip endothelialized microvessel model to assess extravasation and endothelial toxicity. In this model, HMW PolyhHbs demonstrated decreased apparent vascular permeability compared to native cell-free hHb and 20 kDa dextran without adversely affecting endothelial cell viability. This work serves to establish this microfluidic platform as a tool for preclinical HBOC screening to predict in vivo safety and efficacy. Finally, this work integrates the areas of HBOCs and microfluidics in a novel collaboration, which generates new pathways to investigate the cellular-level interactions underlying the development of vascular disease states. The microfluidic platform established in this work may be modified to generate increasingly complex disease-specific models, and our HMW PolyhHbs may be used to examine the efficacy of therapeutically modulating hypoxia. We outline early directions of investigation for a microfluidic model of PE using these tools.
Andre Palmer (Advisor)
Eduardo Reategui (Committee Member)
Jeffrey Chalmers (Committee Member)
Jonathan Song (Advisor)
156 p.
Chemical Engineering
HBOCs; microfluidics; hypoxia; RBC substitutes; hemoglobin; extravasation; preeclampsia

Recommended Citations

Citations

  • Wolfe, S. R. (2022). Synthesis of High Molecular Weight Polymerized Human Hemoglobins and Evaluation of Vascular Extravasation in a Microfluidic Model [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu166746995103041

    APA Style (7th edition)

  • Wolfe, Savannah. Synthesis of High Molecular Weight Polymerized Human Hemoglobins and Evaluation of Vascular Extravasation in a Microfluidic Model . 2022. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu166746995103041.

    MLA Style (8th edition)

  • Wolfe, Savannah. "Synthesis of High Molecular Weight Polymerized Human Hemoglobins and Evaluation of Vascular Extravasation in a Microfluidic Model ." Doctoral dissertation, Ohio State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=osu166746995103041

    Chicago Manual of Style (17th edition)

osu166746995103041
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This open access ETD is published by The Ohio State University and OhioLINK.