New Applications of HBOC-201: A 25-Year Review of the Literature

Nanomaterial-related hemoglobin-based oxygen carriers, with emphasis on liposome and nano-capsules, for biomedical applications: current status and future perspectives

Oxygen is necessary for life and plays a key pivotal in maintaining normal physiological functions and treat of diseases. Hemoglobin-based oxygen carriers (HBOCs) have been studied and developed as a replacement for red blood cells (RBCs) in oxygen transport due to their similar oxygen-carrying capacities. However, applications of HBOCs are hindered by vasoactivity, oxidative toxicity, and a relatively short circulatory half-life. With advancements in nanotechnology, Hb encapsulation, absorption, bioconjugation, entrapment, and attachment to nanomaterials have been used to prepare nanomaterial-related HBOCs to address these challenges and pend their application in several biomedical and therapeutic contexts. This review focuses on the progress of this class of nanomaterial-related HBOCs in the fields of hemorrhagic shock, ischemic stroke, cancer, and wound healing, and speculates on future research directions. The advancements in nanomaterial-related HBOCs are expected to lead significant breakthroughs in blood substitutes, enabling their widespread use in the treatment of clinical diseases.

Review of machine perfusion studies in vascularized composite allotransplant preservation

The applications of Vascularized composite allotransplantation (VCA) are increasing since the first successful hand transplantation in 1998. However, the abundance of muscle tissue makes VCA's vulnerable to ischemia-reperfusion injury (IRI), which has detrimental effects on the outcome of the procedure, restricting allowable donor-to-recipient time and limiting its widespread use. The current clinical method is Static cold storage (SCS) and this allows only 6 h before irreversible damage occurs upon reperfusion. In order to overcome this obstacle, the focus of research has been shifted towards the prospect of ex-vivo perfusion preservation which already has an established clinical role in solid organ transplants especially in the last decade. In this comprehensive qualitative review, we compile the literature on all VCA machine perfusion models and we aim to highlight the essentials of an ex vivo perfusion set-up, the different strategies, and their associated outcomes.

Overcoming challenges in managing a high-risk pregnancy with placenta previa and newly diagnosed Bombay phenotype

BACKGROUND

Bombay phenotype is rare and characterized by a lack of H antigen on the surface of red blood cells (RBCs) with naturally occurring anti-H antibodies. The presence of anti-H necessitates the exclusive use of Bombay phenotype RBCs for transfusion. We present a case of a pregnant woman with Bombay phenotype who required urgent cesarean section delivery due to high-risk placenta previa.

CASE DESCRIPTION

A 36-year-old G1P0 woman of Indian origin presented at 36 weeks and 4 days gestation for management of a high-risk pregnancy with complete placenta previa. Bombay phenotype was unexpectedly identified on routine testing. Given the rarity of the blood, advanced gestation, and risk of post-partum hemorrhage associated with complete placenta previa and spontaneous labor, prompt strategic planning commenced for a successful delivery. Two frozen allogeneic Bombay phenotype RBCs were available as part of a concise transfusion plan. Intraoperative cell salvage was successfully employed and allogeneic transfusion was not required.

CONCLUSION

Management of patients with rare blood types can be extremely challenging and guidance for those presenting later in pregnancy is scarce. Our patient's gestational age precluded the use of well-known effective strategies, including hemoglobin optimization, autologous and directed donation, and procurement of large quantities of rare blood. Rather, our approach utilized multidisciplinary expertise and strategic planning to yield a successful outcome.

Silk Fibroin Particles as Carriers in the Development of Hemoglobin-Based Oxygen Carriers

Oxygen therapeutics have a range of applications in transfusion medicine and disease treatment. Synthetic molecules and all-natural or semi-synthetic hemoglobin-based oxygen carriers (HBOCs) have seen success as potential circulating oxygen carriers. However, many early HBOC products stalled in development due to side effects from excess hemoglobin in the blood stream and hemoglobin entering the tissue. To overcome these issues, research has focused on increasing the molecular diameter of hemoglobin by polymerizing hemoglobin molecules or encapsulating hemoglobin in liposomal carriers. This work leverages the properties of silk fibroin, a cytocompatible and non-thrombogenic biopolymer, known to entrap protein-based cargo, to engineer a fully protein-based oxygen carrier. Herein, an all-aqueous solvent evaporation technique was used to form silk particles via phase separation from a bulk polyvinyl alcohol phase (PVA). Particles size was tuned, and particles were formed with and without hemoglobin. The encapsulation efficiency and ferrous state of hemoglobin were analyzed, resulting in 60% encapsulation efficiency and a maximum of 20% ferric hemoglobin, yielding 100 µg/mL active hemoglobin in certain sfHBOC formulations. The system did not elicit a strong inflammation response in vitro, demonstrating the potential for this particle system to serve as an injectable HBOC.

Protective Effect of Modified Hemoglobin on Rabbits and Goats in High-Altitude Sickness

The prevalence and severity of high-altitude sickness increases with increasing altitude. Prevention of hypoxia caused by high-altitude sickness is an urgent problem. As a novel oxygen-carrying fluid, modified hemoglobin can carry oxygen in a full oxygen partial pressure environment and release oxygen in a low oxygen partial pressure environment. It is unclear whether modified hemoglobin can improve hypoxic injury on a plateau. Using hypobaric chamber rabbit (5000 m) and plateau goat (3600 m) models, general behavioral scores and vital signs, hemodynamic, vital organ functions, and blood gas are measured. The results show that the general behavioral scores and vital signs decrease significantly in the hypobaric chamber or plateau, and the modified hemoglobin can effectively improve the general behavioral scores and vital signs in rabbits and goats, and reduce the degree of damage to vital organs. Further studies reveal that arterial partial pressure of oxygen (PaO2 ) and arterial oxygen saturation (SaO2 ) on the plateau decrease rapidly, and the modified hemoglobin could increase PaO2 and SaO2 ; thus, increasing the oxygen-carrying capacity. Moreover, modified hemoglobin has few side effects on hemodynamics and kidney injury. These results indicate that modified hemoglobin has a protective effect against high-altitude sickness.

Silk Fibroin Particles as Carriers in the Development of All-Natural Hemoglobin-Based Oxygen Carriers (HBOCs)

Oxygen therapeutics have a range of applications in transfusion medicine and disease treatment. Synthetic molecules and all-natural or semi-synthetic hemoglobin-based oxygen carriers (HBOCs) have seen success as potential circulating oxygen carriers. However, many early HBOC products were removed from the market due to side effects from excess hemoglobin in the blood stream and hemoglobin entering the tissue. To overcome these issues, research has focused on increasing the molecular diameter of hemoglobin by polymerizing hemoglobin molecules or encapsulating hemoglobin in liposomal carriers, where immune responses and circulation times remain a challenge. This work looks to leverage the properties of silk fibroin, a cytocompatible and non-thrombogenic biopolymer, known to entrap protein-based cargo, to engineer a silk fibroin-hemoglobin-based oxygen carrier (sfHBOC). Herein, an all-aqueous solvent evaporation technique was used to form silk fibroin particles with and without hemoglobin to tailor the formulation for specific particle sizes. The encapsulation efficiency and ferrous state of hemoglobin were analyzed, resulting in 60% encapsulation efficiency and a maximum of 20% ferric hemoglobin, yielding 100 µg/mL active hemoglobin in certain sfHBOC formulations. The system did not elicit a strong inflammation response in vitro, demonstrating the potential for this particle system to serve as an injectable HBOC.

Controls of Central and Peripheral Blood Pressure and Hemorrhagic/Hypovolemic Shock

The pressure exerted on the heart and blood vessels because of blood flow is considered an essential parameter for cardiovascular function. It determines sufficient blood perfusion, and transportation of nutrition, oxygen, and other essential factors to every organ. Pressure in the primary arteries near the heart and the brain is known as central blood pressure (CBP), while that in the peripheral arteries is known as peripheral blood pressure (PBP). Usually, CBP and PBP are correlated; however, various types of shocks and cardiovascular disorders interfere with their regulation and differently affect the blood flow in vital and accessory organs. Therefore, understanding blood pressure in normal and disease conditions is essential for managing shock-related cardiovascular implications and improving treatment outcomes. In this review, we have described the control systems (neural, hormonal, osmotic, and cellular) of blood pressure and their regulation in hemorrhagic/hypovolemic shock using centhaquine (Lyfaquin^®) as a resuscitative agent.

Neurointerventional infusion of hemoglobin oxygen carrier prevents brain damage from acute cerebral ischemia in rats

Aim

To save brain cells in acute cerebral infarction by injecting hemoglobin oxygen carrier (HBOC) into the blood vessel blockage of the cerebral infarction site through a microcatheter.

Methods

120 male rats were divided into four groups: control (CTRL), ischemia (I), ischemia + low perfusion (I + LP), and ischemia + high perfusion (I + HP). Perfusion groups (ischemia, I + LP, and I + HP) underwent MCAO surgery with intraluminal monofilament. These groups were subdivided into 6 h, 12 h, and 24 h (n = 10/group). RT-PCR, Western-Blot, immunohistochemistry, and apoptosis assays were used to detect apoptosis, hypoxia range and extent, and ischemia.

Results

Compared with the I group, the neurological deficit sign scores of the I + HP group were statistically significant at 12 h. Compared with the I group, the neurological deficit sign scores of the I + LP group and the I + HP group were statistically significant at 24 h. At all time points, compared with the I group and the I + LP group, Caspase-3, HIF-1α, and Cytochrome C protein levels were significantly decreased in the I + HP group. Bcl-2 and BAX mRNA levels were also significantly decreased in the same group. TNF-α, IL-6, and IL-1β cytokines were significantly decreased in the I + HP group as well. The infarct size of rats in the I + HP group was smaller than that of the I + LP group, which was smaller than ischemia alone. Time of perfusion had an obvious effect as infarct size was smaller with longer perfusion. The number of Nissl stained cells in the I + HP group was increased compared with the ischemia and the I + LP group, and was proportional to the time of perfusion.

Conclusion

Time- and rate-controlled perfusion of HBOC to acutely occluded cerebral vascular regions through microcatheters can effectively protect ischemic brain tissue in rats.

Use of cell salvage and HBOC-201 in a pregnant Jehovah's Witness with sickle beta+thalassaemia undergoing emergency caesarean section

Patients with severe anaemia who refuse or cannot safely receive red cell transfusion present challenges during pregnancy, delivery and the postpartum period. Strategies including HBOC-201 (Hemopure) and intraoperative use of cell salvage have been used in non-pregnant patients to improve oxygen carrying capacity; however, these products pose unique risks in pregnant patients, those with sickle cell disease (SCD) and those undergoing caesarean section (C-section). We describe a case of a pregnant sickle beta+thalasasaemia patient who presented at 27 weeks gestation with pre-eclampsia and severe anaemia. As a Jehovah's Witness, she declined allogenic blood transfusion. The patient successfully underwent emergent C-section with cell salvage and received HBOC-201 immediately after delivery, during the operative procedure. To our knowledge, this is the first published report documenting a Jehovah's Witness patient with SCD who successfully received cell salvage and then HBOC-201 immediately postdelivery.

HBOC-301 in Porcine Kidney Normothermic Machine Perfusion and the Effect of Vitamin C on Methemoglobin Formation

Normothermic machine perfusion (NMP) of kidneys in combination with an optimized perfusate composition may increase donor organ preservation quality, especially in the case of marginal donor grafts. Optimization of currently employed perfusates is still a subject of present research. Due to the advantages of being cell-free, easy to store, and having minimal antigenicity, hemoglobin-based oxygen carriers, such as HBOC-301 (Oxyglobin^®, Hemoglobin Oxygen Therapeutics LLC, Souderton, PA, USA), offer an alternative to the commonly used perfusates based on packed red blood cells (pRBC). As previously described, using HBOC results in formation of methemoglobin (metHb) as an adverse effect, inducing hypoxic conditions during the perfusion. As a potential counterpart to metHb formation, the application of the antioxidant ascorbic acid (VitC) is of high interest. Therefore, this study was conducted in four experimental groups, to compare the effect of NMP with (1) HBOC or (3) pRBC, and additionally examine a beneficial effect of VitC in both groups (2) HBOC + VitC and (4) pRBC + VitC. All groups were subjected to NMP for 6 h at a pressure of 75 mmHg. Kidneys in the HBOC groups had a significantly lower renal blood flow and increasing intrarenal resistance, with reduced renal function in comparison to the pRBC groups, as demonstrated by significantly lower creatinine clearance and higher fractional sodium excretion rates. Clinical chemistry markers for tissue damage (LDH, lactate) were higher in the HBOC groups, whereas no significant histological differences were observed. Although the application of VitC decreased oxidative stress levels, it was not able to significantly increase the outcome parameters mentioned above in either group. This study demonstrated that HBOC-301 is inferior to pRBCs in our porcine kidney NMP model, independent of additional VitC administration. Oxidative stress and fragmentation of the hemoglobin polymers could be detected as a possible reason for these results, hence further research, focusing on the use of cell-free oxygen carriers that do not exhibit this complex of issues, is required.