Hypervolemic infusion of Lumbricus terrestris erythrocruorin purified by tangential-flow filtration.
BACKGROUND
The hemoglobin of the earthworm Lumbricus terrestris (also known as erythrocruorin, or LtEc) is a naturally occurring high-molecular-weight protein assembly (3.6 MDa) that is extremely stable, resistant to oxidation, and transports oxygen similarly to human whole blood. Therefore, LtEc may serve as an alternative to donated human red blood cells. However, a suitable purification process must be developed to produce highly pure LtEc on a large scale that can be evaluated in an animal model to determine the safety and efficacy of LtEc.


METHODS
We used tangential-flow filtration (TFF), an easily scalable and affordable technique, to produce highly pure LtEc from earthworms. The purity, yield, methemoglobin level, viscosity, colloid osmotic pressure, O(2) binding equilibria, and ligand-binding kinetics of the purified LtEc were measured in vitro. The purified LtEc product was then evaluated in hamsters using a hypervolemic infusion model to establish its basic biocompatibility and detect any changes in microcirculatory and systemic variables.


RESULTS
TFF was able to produce LtEc with high purity and yield (5-10 g/1000 worms). The purified LtEc product did not elicit hypertension or vasoconstriction when infused into hamsters.


CONCLUSIONS
LtEc may be easily purified and safely transfused into hamsters in small amounts (0.5-1.5 g/dL final concentration in blood) without any noticeable side effects. Therefore, LtEc may serve as a very promising oxygen carrier for use in transfusion medicine.
William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio 43210, USA.
Jacob
J
Elmer
Katie
K
Zorc
Shahid
S
Rameez
Yipin
Y
Zhou
Pedro
P
Cabrales
Andre F
AF
Palmer
D000818:Animals; D001160:Arterioles / Q000502:physiology; D001802:Blood Substitutes / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology; D002417:Cattle; D002853:Chromatography, Liquid; D006224:Cricetinae; D004195:Disease Models, Animal; D004591:Electrophoresis, Polyacrylamide Gel; D005374:Filtration / Q000295:instrumentation / Q000379:methods*; D006454:Hemoglobins / Q000032:analysis / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D008297:Male; D008647:Mesocricetus; D008706:Methemoglobin / Q000032:analysis / Q000302:isolation & purification; D008954:Models, Biological; D008970:Molecular Weight; D009835:Oligochaeta / Q000737:chemistry*; D009997:Osmotic Pressure; D010100:Oxygen / Q000737:chemistry; D012039:Regional Blood Flow / Q000502:physiology; D012769:Shock / Q000097:blood / Q000628:therapy*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014783:Viscosity
D001802:Blood Substitutes; D006454:Hemoglobins; C064665:erythrocruorin; D008706:Methemoglobin; D010100:Oxygen