Biocompatibility of the oxygen carrier polymerized human hemoglobin towards HepG2/C3A cells.

Hemoglobin (Hb) based oxygen carriers (HBOCs) are designed to minimize the toxicity of extracellular Hb, while preserving its high oxygen-carrying capacity for oxygen delivery to cells. Polymerized human Hb (PolyHb) is a novel type of nanosized HBOC synthesized via glutaraldehyde-mediated crosslinking of free Hb, and which preserves the predominant quaternary state during the crosslinking reaction (low oxygen affinity tense (T) quaternary state PolyHb is synthesized at 0% Hb oxygen saturation, and high oxygen affinity relaxed (R) quaternary state PolyHb is synthesized at 100% Hb oxygen saturation). Major potential applications for PolyHbs, and HBOCs in general, include oxygenation of bioreactor systems containing large liver cell masses, and ex-vivo perfusion preservation of explanted liver grafts.

Novel Polymerized Human Serum Albumin For Ex Vivo Lung Perfusion.

Ex vivo lung perfusion (EVLP) is a method of organ preservation to expand the donor pool by allowing organ assessment and repair. Perfusion solution composition is crucial to maintaining and improving organ function during EVLP. EVLP compared perfusates supplemented with either polymeric human serum albumin (PolyHSA) or standard human serum albumin (HSA).

Pilot scale production and characterization of next generation high molecular weight and tense quaternary state polymerized human hemoglobin.

Polymerized human hemoglobin (PolyhHb) is being studied as a possible red blood cell (RBC) substitute for use in scenarios where blood is not available. While the oxygen (O ) carrying capacity of PolyhHb makes it appealing as an O therapeutic, the commercial PolyhHb PolyHeme® (Northfield Laboratories Inc.) was never approved for clinical use due to the presence of large quantities of low molecular weight (LMW) polymeric hemoglobin (Hb) species (<500 kDa), which have been shown to elicit vasoconstriction, systemic hypertension, and oxidative tissue injury in vivo.

Attenuating ischemia-reperfusion injury with polymerized albumin.

Ischemia-reperfusion injury increased vascular permeability, resulting in fluid extravasation from the intravascular compartment into the tissue space. Fluid and small protein extravasation lead to increased interstitial fluid pressure and capillary collapse, impairing capillary exchange. Polymerized human serum albumin (PolyHSA) has an increased molecular weight (MW) compared with unpolymerized human serum albumin (HSA) and can improve intravascular fluid retention and recovery from ischemia-reperfusion injury.

Polymerized albumin restores impaired hemodynamics in endotoxemia and polymicrobial sepsis.

Fluid resuscitation following severe inflammation-induced hypoperfusion is critical for the restoration of hemodynamics and the prevention of multiorgan dysfunction syndrome during septic shock. Fluid resuscitation with commercially available crystalloid and colloid solutions only provides transient benefits, followed by fluid extravasation and tissue edema through the inflamed endothelium. The increased molecular weight (M.

Polymerized human hemoglobin increases the effectiveness of cisplatin-based chemotherapy in non-small cell lung cancer.

Cisplatin is a promising therapeutic for the treatment of non-small cell lung cancer (NSCLC). Unfortunately, a significant portion of NSCLC patients relapse due to cisplatin chemoresistance. This chemoresistance is thought to be primarily associated with hypoxia in the tumor microenvironment.

Tumor vascular status controls oxygen delivery facilitated by infused polymerized hemoglobins with varying oxygen affinity.

Oxygen (O2) delivery facilitated by hemoglobin (Hb)-based O2 carriers (HBOCs) is a promising strategy to increase the effectiveness of chemotherapeutics for treatment of solid tumors. However, the heterogeneous vascular structures present within tumors complicates evaluating the oxygenation potential of HBOCs within the tumor microenvironment. To account for spatial variations in the vasculature and tumor tissue that occur during tumor growth, we used a computational model to develop artificial tumor constructs.

Polymerized human hemoglobin facilitated modulation of tumor oxygenation is dependent on tumor oxygenation status and oxygen affinity of the hemoglobin-based oxygen carrier.

Administration of hemoglobin-based oxygen carriers (HBOCs) into the systemic circulation is a potential strategy to relieve solid tumor hypoxia in order to increase the effectiveness of chemotherapeutics. Previous computational analysis indicated that the oxygen (O) status of the tumor and HBOC O affinity may play a role in increased O delivery to the tumor. However, no study has experimentally investigated how low- and high-affinity HBOCs would perform in normoxic and hypoxic tumors.

Apohemoglobin-haptoglobin complexes attenuate the hypertensive response to low-molecular-weight polymerized hemoglobin.

Polymerized hemoglobin (PolyHb) is a promising hemoglobin (Hb)-based oxygen carrier currently undergoing development as a red blood cell substitute. Unfortunately, commercially developed products are composed of low-molecular-weight (LMW) PolyHb molecules, which extravasate, scavenge nitric oxide, and result in vasoconstriction and hypertension. The naturally occurring Hb-scavenging species haptoglobin (Hp), combined with the purified heme-scavenging species apohemoglobin (apoHb), is a potential candidate to alleviate the pressor effect of PolyHb.

Comprehensive characterization of tense and relaxed quaternary state glutaraldehyde polymerized bovine hemoglobin as a function of cross-link density.

Previously, our lab developed high molecular weight (MW) tense (T) quaternary state glutaraldehyde polymerized bovine hemoglobins (PolybHbs) that exhibited reduced vasoactivity in several small animal models. In this study, we prepared PolybHb in the T and relaxed (R) quaternary state with ultrahigh MW (>500 kDa) with varying cross-link densities, and investigated the effect of MW on key biophysical properties (i.e.

Polymerized Hemoglobin With Increased Molecular Size Reduces Toxicity in Healthy Guinea Pigs.

Hemoglobin (Hb)-based oxygen (O) carriers (HBOCs) have been developed as an alternative to red blood cells (RBCs) for use in transfusion medicine. HBOCs have many benefits over RBCs; however, previous generations of HBOCs failed in clinical trials due to unanticipated cardiotoxicity. These problems likely originated from vasoconstriction, hypertension, oxidative stress, and the presence of low-molecular-weight (MW) Hb species in the HBOC formulation.

Controlled Polymerization and Ultrafiltration Increase the Consistency of Polymerized Hemoglobin for Use as an Oxygen Carrier.

Polymerized human hemoglobins (PolyhHbs) are a promising class of red blood cell substitute for use in transfusion medicine. Unfortunately, the application of the commonly used glutaraldehyde cross-linking chemistry to synthesize these materials results in a complex mixture of PolyhHb molecules with highly varied batch-to-batch consistency. We implemented a controlled method of gas exchange and reagent addition that results in a homogeneous PolyhHb product.

Novel manufacturing method for producing apohemoglobin and its biophysical properties.

Apohemoglobin (apoHb) is a dimeric globular protein with two vacant heme-binding pockets that can bind heme or other hydrophobic ligands. Purification of apoHb is based on partial hemoglobin (Hb) unfolding to facilitate heme extraction into an organic solvent. However, current production methods are time consuming, difficult to scale up, and use highly flammable and toxic solvents.

The quaternary state of polymerized human hemoglobin regulates oxygenation of breast cancer solid tumors: A theoretical and experimental study.

A major constraint in the treatment of cancer is inadequate oxygenation of the tumor mass, which can reduce chemotherapeutic efficacy. We hypothesize that polymerized human hemoglobin (PolyhHb) can be transfused into the systemic circulation to increase solid tumor oxygenation, and improve chemotherapeutic outcomes. By locking PolyhHb in the relaxed (R) quaternary state, oxygen (O2) offloading at low O2 tensions (<20 mm Hg) may be increased, while O2 offloading at high O2 tensions (>20 mm Hg) is facilitated with tense (T) state PolyhHb.

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

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.

Quantification of Active Apohemoglobin Heme-Binding Sites via Dicyanohemin Incorporation.

Apohemoglobin (apoHb) is produced by removing heme from hemoglobin (Hb). However, preparations of apoHb may contain damaged globins, which render total protein assays inaccurate for active apoHb quantification. Fortunately, apoHb heme-binding sites react with heme via the proximal histidine-F8 (His-F8) residue, which can be monitored spectrophotometrically.