Artificial Oxygen Carriers Research Articles

Artificial blood: where are we now?

Background. The creation of artificial blood (AB) and/or its components can change medicine, but currently available artificial oxygen carriers (AOC) do not perform other blood functions: vascular volume maintenance, coagulation, immunity, transport of neurotransmitters, nutrients and waste.
 Objective. To describe the current situation regarding AB.
 Materials and methods. Analysis of literature data on this issue.
 Results and discussion. The need to create an AB is justified by the high cost of collecting, processing and storing donor blood, low infectious safety of drugs received against HIV, viral hepatitis B and C, cytomegalovirus, etc., reduction of the number of donors, problems with blood incompatibility. Immunological effects of blood transfusions are associated with a higher frequency of infectious processes during surgery, slowing of wound healing and progression of malignant diseases. Requirements for an ideal AB preparation include adequate oxygen uptake and delivery under physiological conditions, no toxic or physiological effects, ability to be eliminated and excreted by the human body, sufficient intravascular half-life, ease of use and storage, stability at room temperature, universal compatibility, availability and low cost, ability to maintain blood pressure and pH, viscosity similar to real blood. Available AOC include oxygen-transport solutions based on hemoglobin and perfluorocarbon compounds (PFC) in the form of emulsions. Natural (human, bovine) or genetically modified hemoglobin is used for the production of the former, and hemoglobin of yeast or bacterial origin can also be used. The advantages of hemoglobin solutions include the increased erythropoietin production, adequate oxygen delivery at a hemoglobin level of 20 g/L without side effects, complete absence of virus transmission and 25 % better reperfusion recovery than with real blood. Potential fields of AOC use include shock, organ ischemia, erythrocyte incompatibility, acute lung injury, organ storage for transplantation, cardioplegia, sickle cell anemia, tumor treatment, and air embolism. The main problem is the release of pro-inflammatory cytokines in response to hemoglobin solution administration. Side effects of these solutions include neuro- and nephrotoxicity, immunosuppression, vasoconstriction, coagulopathy, release of free radicals, and errors in blood tests. In turn, PFC does not bind oxygen, but dissolves it in proportion to the partial pressure. PFC are eliminated by phagocytes and eventually excreted by the lungs during respiration. PFC particles are much smaller than natural erythrocytes (0.2 vs. 7 μm) and are easier to deform, which facilitates their delivery to ischemic areas. Side effects of PFC include transient face flushing, headache and back pain, nausea, fever, anaphylactoid reactions, bleeding tendency, pulmonary edema, and acute right ventricular failure. Because high partial pressures are required to achieve the desired PFC effects, artificial lung ventilation may be required. In addition to hemoglobin-based AOC and PFC, hemoglobin in liposomal erythrocyte form, hemoglobin in nanocapsules, nanoarchitectonic complexes of hemoglobin are under development.
 Conclusions. 1. The creation of AB may revolutionize medicine. 2. The need to create an AB is justified by the high cost of collection, processing and storage of donor blood, its low infectious safety, reduction of the number of donors, problems due to blood incompatibility. 3. AOC include hemoglobin-based oxygen-transporting solutions and PFC emulsions. 4. Further studies are needed to improve existing AB preparations and create new ones.

Determination of Methemoglobin in Hemoglobin Submicron Particles Using NMR Relaxometry.

Methemoglobin (MetHb) is a hemoglobin (Hb) derivative with the heme iron in ferric state (Fe3+), unable to deliver oxygen. Quantification of methemoglobin is a very important diagnostic parameter in hypoxia. Recently, novel hemoglobin microparticles (Hb-MP) with a narrow size distribution around 700 nm, consisting of cross-linked Hb were proposed as artificial oxygen carriers. The cross-linking of Hb by glutaraldehyde (GA) generates a certain amount of MetHb. Due to the strong light scattering, quantitative determination of MetHb in Hb-MP suspensions by common spectrophotometry is not possible. Here, we demonstrate that 1H2O NMR relaxometry is a perfect tool for direct measurement of total Hb and MetHb concentrations in Hb-MP samples. The longitudinal relaxation rate 1/T1 shows a linear increase with increasing MetHb concentration, whereas the transverse relaxation rate 1/T2 linearly increases with the total Hb concentration. In both linear regressions the determination coefficient (R2) is higher than 0.99. The method does not require time-consuming pretreatment or digestion of the particles and is not impaired by light scattering. Therefore, it can be established as the method of choice for the quality control of Hb-MP and similar hemoglobin-based oxygen carriers in the future.

Preparation of an Oxygen-Releasing Capsule for Large-Sized Tissue Regeneration

Sufficient oxygenation for prevention of cellular damage remains a critical barrier to successful tissue engineering, especially in the construction of a large-sized tissue despite numerous attempts to resolve this issue in recent years. There have been a number of hypothetical solutions to this problem, including the use of artificial oxygen carriers, induction of vascularization, and fabrication of oxygen-generating biomaterials. All of these efforts have improved the efficiency of oxygen supply, but none have been able to support the large tissue mass required for clinical application. Necrosis, which often occurs during hypoxic stress, is one of the most significant limitations in large-sized tissue regeneration. In this study, we developed an oxygen producing capsule using hydrogen peroxide (H2O2), PLGA (poly (lactic-co-glycolic acid) and alginate, and also evaluated the capsule as a model of a large-sized tissue. Firstly, H2O2 was microencapsulated by PLGA, and subsequently the H2O2-PLGA microspheres were embedded into a catalase-immobilized alginate capsule of 5.0 mm in diameter. The alginate capsules of a fairly large size were characterized for their oxygenation capability to cells embedded such as human umbilical vein endothelial cells (HUVECs) by HIF-1α and VEGF expression. The results of this study confirmed that in the oxygen-releasing capsule composed of H2O2 polymeric microspheres and catalase-bound alginate, HUVEC cells successfully survived in the hypoxic state. These results demonstrated that our oxygen producing system containing H2O2-PLGA microspheres could be a useful oxygenating biomaterial for engineering large-sized tissue.

The need for an artificial oxygen carrier for disasters and pandemics, including COVID-19.

R.B. Weiskopf has consulted for sponsors of hemoglobin-based oxygen carriers in the past, but has not received any compensation from these entities in the past 3 years. M.F.M. James has consulted with sponsors of hemoglobin-based oxygen carriers in the past but has received no financial compensation for these activities at any time. P. Ness has consulted for sponsors of hemoglobin-based oxygen carriers in the past, but has not received any compensation from these entities in the past 3 years. E. Glassberg, N. Guinn, and A.E. Pusateri declare no conflicts of interest.

Efficacy of resuscitative infusion with hemoglobin vesicles in rabbits with massive obstetric hemorrhage

Hemoglobin vesicles have been developed as artificial oxygen carriers, and they have the potential to serve as a substitute for red blood cell transfusion. This study aimed to evaluate the efficacy of hemoglobin vesicle infusion for the initial treatment instead of red blood cell transfusion in rabbits with massive obstetric hemorrhage. Pregnant New Zealand white rabbits (28th day of pregnancy; normal gestation period, 29-35 days) underwent uncontrolled hemorrhage to induce shock by transecting the right midartery and concomitant vein in the myometrium. Subsequently, rabbits received isovolemic fluid resuscitation through the femoral vein with an equivalent volume of hemorrhage every 5 minutes. Resuscitative infusion regimens included 5% human serum albumin (n=6), stored washed red blood cells with plasma (vol/vol=1:1; n=5), and hemoglobin vesicle with 5% human serum albumin (vol/vol=4:1; n=5). A total of 60 minutes after the start of bleeding, rabbits underwent surgical hemostasis by ligation of the bleeding vessels and then were monitored for survival within 24 hours. During fluid resuscitation, hemoglobin vesicle infusion and red blood cell transfusion maintained a mean arterial pressure of >50 mm Hg and a hemoglobin concentration of >9 g/dL and prevented the elevation of plasma lactate. In contrast, resuscitation with 5% human serum albumin alone could not prevent hemorrhagic shock as evidenced by a low mean arterial pressure (40 mm Hg), a low hemoglobin concentration (2 g/dL), and a marked elevation of plasma lactate. All animals in the red blood cell group and the hemoglobin vesicle group survived more than 8 hours, whereas all animals in the 5% human serum albumin group died within 8 hours. Hemoglobin vesicle infusion may be effective in the initial management of massive obstetric hemorrhage.

Albumin-derived perfluorocarbon-based artificial oxygen carriers can avoid hypoxic tissue damage in massive hemodilution

Artificial blood for clinical use is not yet available therefore, we previously developed artificial oxygen carriers (capsules) and showed their functionality in vitro and biocompatibility in vivo. Herein, we assessed the functionality of the capsules in vivo in a normovolemic hemodilution rat-model. We stepwise exchanged the blood of male Wistar-rats with medium either in the presence of capsules (treatment) or in their absence (control). We investigated tissue hypoxia thoroughly through online biomonitoring, determination of enzyme activity and pancreatic hormones in plasma, histochemical and immunohistochemical staining of small intestine, heart, liver and spleen as well as in situ hybridization of kidneys. After hemodilution, treated animals show higher arterial blood pressure and have a stable body temperature. Additionally, they show a more stable pH, a higher oxygen partial pressure (pO2), and a lower carbon dioxide partial pressure (pCO2). Interestingly, blood-glucose-levels drop severely in treated animals, presumably due to glucose consumption. Creatine kinase values in these animals are increased and isoenzyme analysis indicates the spleen as origin. Moreover, the small intestine of treated animals show reduced hypoxic injury compared to controls and the kidneys have reduced expression of the hypoxia-inducible erythropoietin mRNA. In conclusion, our capsules can prevent hypoxic tissue damage. The results provide a proof of concept for capsules as adequate erythrocyte substitute.

Use of Hemoglobin for Delivering Exogenous Carbon Monoxide in Medicinal Applications.

Carbon Monoxide (CO), at low concentrations, can have a variety of positive effects on the body including anti-apoptosis, anti-inflammatory, anti-oxidative and anti-proliferative effects. Although CO has great potential for use as a potent medical bioactive gas, for it to exist in the body in stable form, it must be associated with a carrier. Hemoglobin (Hb) represents a promising material for use as a CO carrier because most of the total CO in the body is stored associated with Hb in red blood cells (RBC). Attempts have been made to develop an Hb-based CO carrying system using RBC and Hb-based artificial oxygen carriers. Some of these have been reported to be safe and to have therapeutic value as a CO donor in preclinical and clinical studies. In the present review, we overview the potential of RBC and Hb-based artificial oxygen carriers as CO carriers based on the currently available literature evidence for their use in pharmaceutical therapy against intractable disorders.

Prevention of Decompression Sickness by Novel Artificial Oxygen Carriers.

Newly designed albumin-derived perfluorocarbon-based artificial oxygen carriers (A-AOC) are used in a rodent in vivo model as a preventive therapy for decompression sickness (DCS). Thirty-seven rats were treated with A-AOC (n = 12), albumin nanocapsules filled with neutral oil (A-O-N, n = 12), or 5% human serum albumin solution (A-0-0, n = 13) before a simulated dive. Eleven rats, injected with A-AOC, stayed at normal pressure (A-AOC surface). Clinical, laboratory, and histological evaluations were performed. The occurrence of DCS depended on the treatment group. A-AOC significantly reduced DCS appearance and mortality. Furthermore, a significant improvement of survival time was found (A-AOC compared with A-0-0). Histological assessment of A-AOC-dive compared with A-0-0-dive animals revealed significantly higher accumulation of macrophages, but less blood congestion in the spleen and significantly less hepatic circulatory disturbance, vacuolization, and cell damage. Compared with nondiving controls, lactate and myoglobin showed a significant increase in the A-0-0- but not in the A-AOC-dive group. Intravenous application of A-AOC was well tolerated and effective in reducing the occurrence of DCS, and animals showed significantly higher survival rates and less symptoms compared with the albumin group (A-0-0). Analysis of histological results and fast reacting plasma parameters confirmed the preventive properties of A-AOC.

Alternatives to Transfusion

We discuss two main categories of blood substitutes: perfluorocarbons and hemoglobin-based oxygen carriers. We provide a review of the notable products developed in both categories and include their attributes as well as their setbacks. We contribute a case report tothe growing literature of the successful use of Sanguinate. We find that artificial oxygen carriers are an attractive field of research because of the practical limitations and the multitude of potential complications that surround human blood transfusions.

Artificial oxygen carrier improves fatigue resistance in slow muscle but not in fast muscle in a rat in situ model.

The effects of liposome-encapsulated hemoglobin with high O2 affinity (h-LEH), an artificial O2 carrier in skeletal muscle, were studied by in situ fatigue resistance test in fast-type plantaris (PLT) and slow-type soleus (SOL) muscles with or without ischemia in the rat. The distal tendons of PLT and SOL muscles were isolated in situ and individually attached to the force transducers to record the developed tension in response to stimuli (80Hz tetanus train, 1.5minutes) to the ipsilateral sciatic nerve. The fatigue resistance test (five sets separated by 2-minute rests) was evaluated in terms of tension attenuation (fatigue) from the initial to the last tension (A) during each set, attenuation of the initial (B) or last tension (C) in each set, as compared to the first set in the presence or absence of ischemia or h-LEH (10mL/kg). While ischemia significantly enhanced fatigue only in PLT, h-LEH showed no effect regardless of the perfusion pattern (normal/ischemia) or muscle-type (PLT/SOL) during each set (A). In parameter (B), set-by-set fatigue development was observed in PLT, whereas h-LEH-SOL showed a trend of advanced fatigue resistance. Such trends became clear in the parameter C (last tension), because h-LEH-SOL exerted, rather than decreased, the tension enhancement regardless of the presence or absence of ischemia, whereas there were no h-LEH effects in PLT. In addition, faster recovery of the nicotinamide adenine dinucleotide content in the muscle after 10minutes of all fatigue tests was observed in h-LEH-SOL, while saline-SOL still showed a significantly higher value than that of control. These results suggested that additional O2 supply by h-LEH may accelerate the tricarboxylic acid cycle/electron transport chain in slow-type aerobic SOL muscle containing abundant mitochondria and contribute to the faster removal of muscle fatigue substances such as lactate.

Inhibiting Hypoxia and Chemotherapy-Induced Cancer Cell Metastasis under a Valid Therapeutic Effect by an Assistance of Biomimetic Oxygen Delivery.

Tumor metastasis is the most dangerous stage in tumorigenesis and its evolution, which causes about 80% clinical death. However, common therapies including chemotherapy may increase the risk of tumor metastasis while killing cancer cells. Tumor metastasis is closely related to many factors in the tumor microenvironment, especially hypoxia. As one of the characteristics of a malignant tumor microenvironment, hypoxia plays an important role in the growth, metabolism, and metastasis of tumors. Upregulation of the hypoxia-inducible factor (HIF) would stimulate the metastasis and migration of cancer cells. In this study, we developed an artificial oxygen carrier system, a hemoglobin-loaded liposome (Hb@lipo), which was capable of effectively delivering oxygen to tumor. The way of providing oxygen not only alleviated tumor hypoxia but also downregulated the expression of HIF, which is conducive to reducing tumor malignancy. Alleviating the tumor hypoxic microenvironment alone is not enough to inhibit tumor metastasis; thus, we prepared the liposome containing a chemotherapeutic agent cabazitaxel (CBZ@lipo). Our data indicated that the combination therapy of Hb@lipo and CBZ@lipo can efficiently kill cancer cells and inhibit tumor growth. At the same time, it can effectively entrap cancer cells in tumor sites by relieving the hypoxic microenvironment of tumors and reduce the metastasis of cancer cells during and after the chemotherapy. Our research may provide a clinical cancer chemotherapy reference that reduces the risk of cancer cell metastasis while inhibiting tumor growth.

Mini-review: Perfluorocarbons, Oxygen Transport, and Microcirculation in Low Flow States: in Vivo and in Vitro Studies.

The in vivo study of microvascular oxygen transport requires accurate and challenging measurements of several mass transfer parameters. Although recommended, blood flow and oxygenation are typically not measured in many studies where treatments for ischemia are tested. Therefore, the aim of this communication is to briefly review cardinal aspects of oxygen transport, and the effects of perfluorocarbon (PFC) treatment on blood flow and oxygenation based mostly on studies performed in our laboratory. As physiologically relevant events in oxygen transport take place at the microvascular level, we implemented the phosphorescence quenching technique coupled with noninvasive intravital videomicroscopy for quantitative evaluation of these events in vivo. Rodent experimental models and various approaches have been used to induce ischemia, including hemorrhage, micro- and macroembolism, and microvessel occlusion. Measurements show decrease in microvascular blood flow as well as intravascular and tissue oxygen partial pressure (PO2) after these procedures. To minimize or reverse the effects of ischemia and hypoxia, artificial oxygen carriers such as different PFCs were tested. Well-defined endpoints such as blood flow and tissue PO2 were measured because they have significant effect on tissue survival and outcome. In several cases, enhancement of flow and oxygenation could be demonstrated. Similar results were found in vitro: PFC emulsion mixed with blood (from healthy donors and sickle cell disease patients) enhanced oxygen transport. In summary, PFCs may provide beneficial effects in these models by mechanisms at the microvascular level including facilitated diffusion and bubble reabsorption leading to improved blood flow and oxygenation.

Pharmaceutical design and development of perfluorocarbon nanocolloids for oxygen delivery in regenerative medicine.

Perfluorocarbons (PFCs) have been investigated as oxygen carriers for several decades in varied biomedical applications. PFCs are chemically and biologically inert, temperature and storage stable, pose low to no infectious risk, can be commercially manufactured, and have well established gas transport properties. In this review, we highlight design and development strategies for their successful application in regenerative medicine, transplantationand organ preservation. Effective tissue preservation strategies are key to improving outcomes of extremity salvage and organ transplantation. Maintaining tissue integrity requires adequate oxygenation to support aerobic metabolism. The use of whole blood for oxygen delivery is fraught with limitations of poor shelf stability, infectious risk, religious exclusionsand product shortages. Other agents also face clinical challenges in their implementation. As a solution, we discuss new ways of designing and developing PFC-based artificial oxygen carriers by implementing modern pharmaceutical quality by design and scale up manufacturing methodologies.

Prolonged functional life span of artificial red cells in blood circulation by repeated methylene blue injections

Hemoglobin-vesicles (HbVs) are artificial oxygen carriers encapsulating purified and concentrated hemoglobin solution in phospholipid vesicles (liposomes) and their safety and efficacy as a transfusion alternative have been evaluated. Because of the absence of enzymatic methemoglobin reduction system in HbV, the level of ferric methemoglobin (metHb) increases gradually after intravenous administration. Our previous studies clarified that the glycolytic electron energies, charged as NAD(P)H in red blood cells (RBC), are donated to reduce metHb compartmentalized in HbV via a water-soluble electron mediator such as methylene blue [MB; 3,7-bis(dimethylamino)phenothiazinium chloride], which freely shuttle across both RBC biomembrane and HbV lipid membrane. Herein, we tried to test repeated injections of MB after the massive HbV administration (28 mL/kg) to hemorrhagic shocked Wistar rats (n = 3). MB was injected (3.1 mg/kg) at 7, 24 and 48 h after HbV administration. Every MB injection showed rapid reduction of metHb and gradual reversal increase. As a result, the functional life span of HbV was significantly extended over 60 h. It is expected that further optimization of injection scheduling will decrease the total amount of MB and prolong the functional life span of HbV.

Blood Substitutes and Oxygen Therapeutics: A Review.

Despite the exhaustive search for an acceptable substitute to erythrocyte transfusion, neither chemical-based products such as perfluorocarbons nor hemoglobin-based oxygen carriers have succeeded in providing a reasonable alternative to allogeneic blood transfusion. However, there remain scenarios in which blood transfusion is not an option, due to patient's religious beliefs, inability to find adequately cross-matched erythrocytes, or in remote locations. In these situations, artificial oxygen carriers may provide a mortality benefit for patients with severe, life-threatening anemia. This article provides an up-to-date review of the history and development, clinical trials, new technology, and current standing of artificial oxygen carriers as an alternative to transfusion when blood is not an option.

Artificial oxygen carriers and red blood cell substitutes: A historic overview and recent developments toward military and clinical relevance.

Packed red blood cells are a critical component in the resuscitation of hemorrhagic shock. The availability of donor-derived blood products, however, suffers from issues of supply, immunogenicity, and pathogenic contamination. Deployment in remote or austere environments, such as the battlefield, is further hindered by the inherent perishability of blood products. To address the significant limitations of allogenic packed red blood cells and the urgent medical need for better resuscitative therapies for both combat casualties and civilians, there has been significant research invested in developing safe, effective, and field deployable artificial oxygen carriers. This article provides a comprehensive review of the most important technologies in the field of artificial oxygen carriers including cell-free and encapsulated hemoglobin-based oxygen carriers, perfluorocarbon emulsions, natural hemoglobin alternatives, as well as other novel technologies. Their development status, clinical, and military relevance are discussed. LEVEL OF EVIDENCE: Systematic review.

Artificial Oxygen Carriers—Past, Present, and Future—a Review of the Most Innovative and Clinically Relevant Concepts

Blood transfusions are a daily practice in hospitals. Since these products are limited in availability and have various, harmful side effects, researchers have pursued the goal to develop artificial blood components for about 40 years. Development of oxygen therapeutics and stem cells are more recent goals. Medline (https://www.ncbi.nlm.nih.gov/pubmed/?holding=ideudelib), ClinicalTrials.gov (https://clinicaltrials.gov), EU Clinical Trials Register (https://www.clinicaltrialsregister.eu), and Australian New Zealand Clinical Trials Registry (http://www.anzctr.org.au) were searched up to July 2018 using search terms related to artificial blood products in order to identify new and ongoing research over the last 5 years. However, for products that are already well known and important to or relevant in gaining a better understanding of this field of research, the reader is punctually referred to some important articles published over 5 years ago. This review includes not only clinically relevant substances such as heme-oxygenating carriers, perfluorocarbon-based oxygen carriers, stem cells, and organ conservation, but also includes interesting preclinically advanced compounds depicting the pipeline of potential new products. In- depth insights into specific benefits and limitations of each substance, including the biochemical and physiologic background are included. "Fancy" ideas such as iron-based substances, O2 microbubbles, cyclodextranes, or lugworms are also elucidated. To conclude, this systematic up-to-date review includes all actual achievements and ongoing clinical trials in the field of artificial blood products to pursue the dream of artificial oxygen carrier supply. Research is on the right track, but the task is demanding and challenging.

Size-Controlled Preparation of Microsized Perfluorocarbon Emulsions as Oxygen Carriers via the Shirasu Porous Glass Membrane Emulsification Technique.

We have developed microsized perfluorocarbon (PFC) emulsions with different sizes as artificial oxygen carriers (OCs) via Shirasu porous glass membrane emulsification. Monodispersed PFC emulsions with narrow size distribution were obtained. By changing the membrane pore size, we were able to precisely control the size of emulsions and fabricate emulsions similar in size to human red blood cells. Behaviors of Pluronics with different physiochemical properties (F127, F68, P85, and P103) as surfactants were also investigated, which evidenced that the type and concentration of Pluronics have a major impact on the size of emulsions and the response to different thermal conditions. The F127-stabilized microsized PFC emulsions were stable even during autoclave sterilization. The emulsions were loaded with Ru(ddp)-an oxygen-sensitive probe-on their surfaces to indicate oxygen concentration. Finally, incubations with HeLa cells that show fluorescence in response to hypoxia cultured in 2D and 3D suggested promising potential of our emulsions for OCs.

Ring-Opening Polymerization of Hemoglobin.

Hemoglobin (Hb), an oxygen-carrying protein, has an α2β2 tetrameric structure that dissociates reversibly into two αβ dimers (α2β2 ⇄ 2αβ). We synthesized a cyclic Hb-ring monomer with two β subunits bound through a 10 kDa polyethylene glycol (PEG) chain. The monomer induced ring-opening polymerization to produce a supramolecular polymer via intersubunit interaction of αβ dimers of an Hb molecule at the PEG terminals. Both the ring-closed monomer and the ring-opened supramolecular polymer were then fixed covalently by intramolecular cross-linking of two β subunits. Quantification of fixed products at various monomer concentrations revealed the equilibrium constant ( K), a ratio of propagation and depropagation rate constants, as 5.68 mM-1. The average degree of polymerization ([Formula: see text]) increased proportionally, concomitantly with the initial monomer concentration. Hb polymer with [Formula: see text] = 13.2 ( Mn = ca. 1 MDa) was obtained by cross-linking at 2.33 mM. Our novel strategy of ring-opening polymerization of Hb will eventually realize a highly aligned and efficiently polymerized Hb for creating artificial oxygen carriers for a clinical use.

PEGylated carboxyhemoglobin bovine (SANGUINATE) ameliorates myocardial infarction in a rat model.

Artificial oxygen (O2) carriers were reported to be protective in ischemia/reperfusion (I/R) in various organs including the heart. In the current study, 20 rats underwent ligation (MI) of the left anterior descending artery, were treated with 10 mL/kg of PEGylated carboxyhemoglobin bovine (SANGUINATE, S+, n = 10) or saline (S−, n = 10) 10 minutes after MI and daily thereafter for 3 days, and were followed by weekly echocardiography for 4 weeks, when they had left ventricular pressure volume relationship (PVR) analyses followed by necropsy. Echocardiography showed an increase in end‐systolic dimension rather than end‐diastolic dimension, preserved fractional shortening (36 vs. 26%, P < .01), and milder mitral regurgitation in S+ compared with S‐ rats. PVR revealed a milder increase in end‐systolic volume, larger stroke volume (101 vs. 74 μL, P < .005) and cardiac output (33.4 vs. 23.8 mL/min, P = .004) in S+ rats in actual determination and under a wide range of standardized loading conditions 4 weeks after MI. Excised heart showed significantly limited area of MI (8.9 vs. 13.3%, P = .028). The results suggest that SANGUINATE in short‐term repeated doses may accelerate weight recovery, preserving the myocardium, mitral competence, and cardiac function after MI. The mechanism of action and optimal treatment for MI remain to be studied.