Validation of virus inactivation by heat treatment in the manufacture of diaspirin crosslinked hemoglobin

The impact of thermal pasteurization on viral load and detectable live viruses in human milk and other matrices: a rapid review

Holder pasteurization (62.5 °C, 30 min) of human milk is thought to reduce the risk of transmitting viruses to an infant. Some viruses may be secreted into milk - others may be contaminants. The effect of thermal pasteurization on viruses in human milk has yet to be rigorously reviewed. The objective of this study is to characterize the effect of common pasteurization techniques on viruses in human milk and non-human milk matrices. Databases (MEDLINE, Embase, Web of Science) were searched from inception to April 20th, 2020, for primary research articles assessing the impact of pasteurization on viral load or detection of live virus. Reviews were excluded, as were studies lacking quantitative measurements or those assessing pasteurization as a component of a larger process. Overall, of 65 131 reports identified, 109 studies were included. Pasteurization of human milk at a minimum temperature of 56-60 °C is effective at reducing detectable live virus. In cell culture media or plasma, coronaviruses (e.g., SARS-CoV, SARS-CoV-2, MERS-CoV) are highly susceptible to heating at ≥56 °C. Although pasteurization parameters and matrices reported vary, all viruses studied, except parvoviruses, were susceptible to thermal killing. Future research important for the study of novel viruses should standardize pasteurization protocols and should test inactivation in human milk. Novelty In all matrices, including human milk, pasteurization at 62.5 °C was generally sufficient to reduce surviving viral load by several logs or to below the limit of detection. Holder pasteurization (62.5 °C, 30 min) of human milk should be sufficient to inactivate nonheat resistant viruses, including coronaviruses, if present.

Effects of Diaspirin Crosslinked Hemoglobin (DCLHb) on microcirculation and local tissue pO2 of striated skin muscle following resuscitation from hemorrhagic shock

The hemoglobin based oxygen carrier (HBOC) Diaspirin Crosslinked Hemoglobin (DCLHb) has been developed to substitute not only the blood volume, but also to restore the oxygen-carrying properties of blood during hemorrhagic shock. However, it has been suggested that HBOCs may enhance the formation of free oxygen radicals through the release of free iron ions via the Haber-Weiss reaction. The aim of this study was to investigate the effects of DCLHb on the microcirculation, leukocyte-endothelial cell interaction and local tissue oxygenation in striated skin muscle of Syrian golden hamsters during and after resuscitation from hemorrhagic shock. In particular we focused on the local tissue oxygenation after resuscitation with DCLHb (hemoglobin content 10 g%) compared to resuscitation using autologous blood diluted to a hemoglobin content of 10 g%. Hemorrhagic shock was induced for 45 minutes by bleeding the animals at a rate of 33 ml/kg BW maintaining a mean arterial pressure of 30 +/- 5 mmHg. Animals were resuscitated either with 33 ml/kg BW 6% Dextran-60.000 or with 10 g% DCLHb. The control group received shed blood diluted with Ringers to a hemoglobin content of 10 g%. Intravital microscopy was used for investigation of the microcirculatory parameters and a multiwire platinum surface electrode for measurement of local tissue pO2 in striated skin muscle in the dorsal skinfold chamber of Syrian golden hamsters. Resuscitation from hemorrhagic shock with 10 g% AUB revealed significant increase of leukocytes rolling in postcapillary venules at 30 to 120 minutes after resuscitation compared to baseline values. DCLHb turned out to reduce the number of firmly adherent leukocytes after resuscitation compared to 10 g% AUB. Microvascular permeability as an indicator for functional endothelial integrity revealed no significant differences between the groups. DCLHb and 10 g% AUB led to a significant increase in local tissue oxygenation after resuscitation from hemorrhagic shock. However, 10 g% AUB turned out to be most effective to restore the local tissue pO2 compared to Dx-60. Our findings indicate that DCLHb restores microvascular perfusion after critical hemorrhagic shock as efficient as Dx-60 and 10 g% AUB. The absence of enhanced leukocyte-endothelium interaction after resuscitation with DCLHb implies that this HBOC does not exacerbate formation of oxygen free radicals during reperfusion. DCLHb effectively increases local tissue pO2 after resuscitation from hemorrhagic shock; however, not as effectively as 10 g% AUB.

Duck hepatitis B photoinactivation bydimethylmethylene blue in RBC suspensions

BACKGROUND

Dimethylmethylene blue (DMMB) has been used to photoinactivate a number of model viruses, including VSV, in RBC suspensions under conditions that preserve in vitro RBC properties during storage. The relative sensitivity of duck HBV (DHBV) and VSV to photoinactivation by DMMB was investigated by performing an indirect immunofluorescence assay (IFA) using primary duck hepatocyte (PDH) cultures or a standard plaque assay for the respective viruses.

STUDY DESIGN AND METHODS

DMMB was added to 45-percent Hct, WBC-reduced, oxygenated AS-3 RBCs at 10-, 1-, and 0.1-microM concentrations. Samples (1-mm thick) were illuminated with 5.4-mW per cm(2) of red light for 2 or 9 seconds. Unilluminated samples without DMMB or with 10 microM DMMB served as control.

RESULTS

DHBV and VSV were rapidly photoinactivated by DMMB in a concentration and light-dose-dependent fashion. Neither virus was substantially inactivated by incubation with DMMB in the dark. For a given light exposure, DHBV required a concentration of DMMB one-one hundredth that of VSV to achieve approximately the same level of inactivation.

CONCLUSION

DHBV appears to be considerably more sensitive than VSV to DMMB photoinactivation. Photoinactivation in 45-percent Hct RBCs can be achieved in seconds by using micromolar quantities of dye.

Controlled safety study of a hemoglobin-based oxygen carrier, DCLHb, in acute ischemic stroke

BACKGROUND AND PURPOSE

Diaspirin cross-linked hemoglobin (DCLHb) is a purified, cell-free human hemoglobin solution. In animal stroke models its use led to a significant reduction in the extent of brain injury. The primary objective of this study was to evaluate the safety of DCLHb in patients with acute ischemic stroke.

METHODS

DCLHb or saline was administered to 85 patients with acute ischemic stroke in the anterior circulation, within 18 hours of onset of symptoms, in a multicenter, randomized, single-blind, dose-finding, controlled safety trial, consisting of 3 parts: 12 doses of 25, 50, and 100 mg/kg DCLHb over 72 hours.

RESULTS

DCLHb caused a rapid rise in mean arterial blood pressure. The pressor effect was not accompanied by complications or excessive need for antihypertensive treatment. Two patients in the 100 mg/kg group had adverse events that were possibly drug related: one suffered fatal brain and pulmonary edema, the other transient renal and pancreatic insufficiency. Multivariate logistic regression analysis showed that a severe stroke at baseline and treatment with DCLHb (OR, 4.0; CI, 1.4 to 12.0) were independent predictors of a worse outcome (Rankin Scale score of 3 to 6) at 3 months.

CONCLUSIONS

Outcome scale scores were worse in the DCLHb group, and more serious adverse events and deaths occurred in DCLHb-treated patients than in control patients. We recommend that additional safety studies be performed, preferably with a second generation, genetically engineered hemoglobin.

Blood substitutes. Haemoglobin therapeutics in clinical practice

Early approaches to the development of oxygen carriers involved the use of stroma-free hemoglobin solutions. These solutions did not require blood typing or crossmatching and could be stored for long periods. In addition, a variety of methods have been developed in chemically modifying and stabilizing the hemoglobin molecule. Several hemoglobin therapeutics are now in clinical trials as temporary alternatives to blood or as therapeutic agents for ischemia. The various hemoglobin products under development are derived from three principal sources: human, bovine and genetically engineered hemoglobin. Diaspirin cross-linked hemoglobin (DCLHb), administered at doses ranging from approximately 20-1000 ml, has been investigated in a number of clinical trials in patients undergoing orthopedic, abdominal aortic repair, major abdominal surgery, cardiac surgery and in critically ill patients with septic shock. In several studies, DCLHb was effective in avoiding the transfusion. However, Baxter Healthcare Corporation (Chicago, Illinois, USA) stopped the development of DCLHb after two unsuccessful trials in trauma patients. Bovine polymerized hemoglobin has also been extensively studied. Several phase II and phase III trials have been performed with this product in hemorrhagic surgery, cardiac surgery and vascular surgery, but data have not yet been published. Hemoglobin therapeutics could provide an important new option as an alternative to blood transfusion. Furthermore, they may be able to provide an immediate on-site replacement for traumatic blood loss, prevent global ischemia and organ failure, treat focal ischemia, and provide effective hemodynamic support for septic shock-induced hypotension.

Effects of diaspirin-cross-linked hemoglobin (DCLHb) on the microcirculation of striated skin muscle in the hamster: a study on safety and toxicity

Hemoglobin-based oxygen-carrying solutions are reported to exert vasoconstrictor effects and to enhance oxygen radical formation, particularly during ischemia-reperfusion. This study investigates whether diaspirin-cross-linked hemoglobin (DCLHb) affects the microvascular integrity of striated skin muscle. The microcirculation model in the hamster and intravital fluorescence microscopy were applied for investigation of the microvascular changes in striated skin muscle. Hypervolemic infusion (500 mg x kg(-1), I.V.) and isovolemic exchange transfusion (3.3 gm x kg(-1) I.V.; hematocrit 30%) with DCLHb (1) led to a short-lasting (0 to 2 minutes) arteriolar constriction (approximately 20% reduction in baseline diameter), (2) significantly influenced arteriolar vasomotion, (3) increased venular red blood cell velocity by 1.5-fold (p < 0.05 vs dextran, Mr 60,000), and (4) did not enhance microvascular leukocyte-endothelium interaction or endothelial permeability. Resuscitation from severe hemorrhagic shock with autologous blood (AuB) or DCLHb (33 ml x kg(-1), I.V.) immediately restored mean arterial pressure and heart rate, whereas 6% dextran (60 kd)(Dx-60) did not return these parameters to baseline. Venular red blood cell velocity was restored to 110% of baseline after DCLHb, to 90% of baseline after AuB, and to 45% of baseline after Dx-60. Leukocyte-endothelium interaction was significantly enhanced after resuscitation with AuB and Dx-60, whereas this phenomenon was absent after DCLHb. These data demonstrate that DCLHb increases venular red blood cell velocity under both nonischemic and postischemic conditions without inducing enhanced leukocyte-endothelium interaction in the microcirculation of striated skin muscle.

Production and characteristics of an infusible oxygen-carrying fluid based on hemoglobin intramolecularly cross-linked with sebacic acid

Research on red cell substitutes requires the availability of oxygen-carrying fluids for physiologic experiments. This article describes the procedure for in-house production of such a fluid. It contains a hemoglobin-based oxygen carrier obtained by reacting human hemoglobin with bis-(3,5-dibromosalicyl) sebacate. This reagent produces intramolecular cross-links between the beta 82 lysines and between the alpha 99 lysines, respectively. The oxygen half-saturation pressure (P50) of the fluid is near 34 mm Hg at 37 degrees C, with a Hill's parameter of n = 2.2. The half-time of intravascular retention is near 3.0 hours in the rat and 6.5 hours in the cat. Spectrophotometric analyses of arterial and venous plasma from an infused rat reveal an efficient oxygen delivery to the tissues by the oxygen carrier. Therefore, this new cross-linked human hemoglobin can be produced in quantities sufficient for in vivo evaluation and with an oxygen affinity and cooperativity adequate for oxygen unloading in plasma.