Phase I study of the safety and pharmacologic effects of diaspirin cross-linked hemoglobin solution.

OBJECTIVE: To evaluate the safety, pharmacokinetics, and pharmacodynamics of diaspirin cross-linked hemoglobin solution (DCLHb) in normal, healthy volunteers. DESIGN: Randomized, double-blind, controlled, crossover study. SETTING: Phase I research facility of a contract research organization. PATIENTS: Twenty-four healthy adult volunteers. INTERVENTIONS: Diaspirin cross-linked hemoglobin solution (25, 50, or 100 mg/kg) or equal volume of lactated Ringer's solution was infused on day 1; the alternate solution was infused 6 days later. Laboratory analyses, electrocardiograms, and Holter and telemetry monitoring were performed to assess organ function, pharmacokinetics, and potential toxicity. Vital signs, pulse oximetry, laser Doppler flowmetry, and toe temperature were measured to evaluate diaspirin cross-linked hemoglobin solution's pharmacodynamic effects. MEASUREMENTS AND MAIN RESULTS: There were no serious adverse events associated with diaspirin cross-linked hemoglobin solution infusion. Abdominal pain occurred in three subjects after control infusion and in six subjects after diaspirin cross-linked hemoglobin solution infusion; no treatment was required. A dose-related increase in lactic dehydrogenase (LDH)-5 isoenzyme concentrations was observed in 12 subjects after diaspirin cross-linked hemoglobin solution infusion. There were no associated increases in the circulating concentrations of total LDH, aspartate aminotransferase, alanine aminotransferase, or alkaline phosphatase. Total serum creatine kinase concentrations increased significantly after infusion of 100 mg/kg of diaspirin cross-linked hemoglobin solution; the isoenzyme creatine kinase-myocardial band (CK-MB) was not increased, nor were there any abnormal electrocardiogram findings. There were no differences in laser Doppler, pulse oximetry, or toe temperature measurements during or after either infusion. The half-life of diaspirin cross-linked hemoglobin solution was 2.5 hrs for the 25- and 50-mg/kg doses and 3.3 hrs for the 100-mg/kg dose. A dose-related increase in blood pressure occurred with diaspirin cross-linked hemoglobin solution. CONCLUSIONS: Diaspirin cross-linked hemoglobin solution doses of 25, 50, and 100 mg/kg are well tolerated, without evidence of organ dysfunction or toxicity. Diaspirin cross-linked hemoglobin solution's pressor effect is without evidence of decreased peripheral perfusion. Further investigations of its use in certain patient populations are warranted.

The effects of alpha-alpha cross-linked hemoglobin on the feeding and locomotor activity of rats.

The feeding and locomotor activities of rats were used as an assay for the potentially toxic effects of an oxygen-carrying blood substitute. Rats lived in individual cages where they could feed ad lib by pressing a lever once for each small food pellet, drink water, or run in a wheel; a 12-h light/dark cycle was continuously in effect. After being anesthetized and hemorrhaged one-third of their total blood volume, individual rats were resuscitated with one of the following fluids: their own shed blood (OB), bis(3,5-dibromosalicylfumarate) alpha-alpha cross-linked hemoglobin (HbXL), human serum albumin (HSA), or Ringer's lactate (RL). Rats in a fifth group were not resuscitated (NR). During the dark period on the day of hemorrhage, the food intake and running activity of rats in all groups decreased. Food intake and locomotor activity of rats in the HbXL, NR and OB groups were more suppressed than the HSA or RL groups. The food intake of rats in the HbXL and NR groups remained significantly more suppressed during the dark period of the first recovery day; running continued to be suppressed in the HbXL group on the first recovery day, but not the second recovery day. In an effort to determine the extent to which the rats in the HbXL group were impaired, an increasing number of lever presses was required for each food pellet beginning with recovery day number 3 for all treatment groups. As the ratio of presses per pellet was increased, food intake decreased and running increased for all groups; no differences between groups were significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Rat maze performance after resuscitation with cross-linked hemoglobin solution.

Unmodified stroma-free hemoglobin has been found to produce neurotoxicity and behavioral impairment in rats. In contrast, a recent assessment of a modified (diaspirin alpha-alpha cross-linked) hemoglobin (HbXL) solution found normal memory, learning, and brain histology after infusion of a clinically relevant dose of a 14% HbXL solution. The current study examined this potential resuscitation fluid for evidence of neurobehavioral toxicity under clinical conditions. Rats were trained to complete a water alley maze, had 50% of their total blood volume (30 ml/kg) withdrawn, were resuscitated with 14% HbXL solution (45 ml/kg), Ringer's lactate (60 ml/kg), or autologous shed blood, and were subsequently retested in the water maze. Rats resuscitated with HbXL or autologous shed blood survived resuscitation, while 20% of those resuscitated with Ringer's lactate died during treatment. No significant performance degradation was observed in the HbXL rats following resuscitation, and no brain pathology was observed at necropsy 10 days after treatment. Ischemic brain lesions were observed in three (25%) of the surviving rats resuscitated with Ringer's lactate solution. Renal tubule regeneration indicative of an earlier insult was observed in animals from all three groups. A significant correlation between the total pathology in the five organs examined and maze errors was observed (p less than 0.001). The survival, maze performance, and histology results suggest that resuscitation with 14% HbXL solution does not cause neurotoxicity, as assessed in this lethal hemorrhage model.

Rat maze performance after infusion of cross-linked hemoglobin solution.

Neurotoxicity and behavioral performance degradation have previously been observed in rats after exchange transfusions with unmodified stroma-free hemoglobin solutions. We evaluated a diaspirin cross-linked stroma-free hemoglobin solution (HbXL) for evidence of neurotoxicity. Rats that were trained to complete a water alley maze received a clinically-relevant dose (20 ml/kg) of the 14% HbXL solution on top of their normal blood volume. After post-treatment memory testing in the water maze, the same rats were challenged to learn an elevated radial-arm maze. The HbXL and control groups showed no water maze performance degradation after treatment, and all groups demonstrated learning of the radial-arm maze as shown by decreased errors and times to completion. The brains, heart, and livers presented normal histology thirty days after infusion, but six of fifteen animals showed marked renal tubular regeneration. The normal memory and learning performance and brain histology after infusion with HbXL suggests that this hemoglobin solution is not neurotoxic to unhemorrhaged rats.