TY - JOUR
T1 - In vivo biodistribution of a radiolabeled blood substitute:99mTc-labeled liposome-encapsulated hemoglobin in an anesthetized rabbit
AU - Rudolph, Alan S.
AU - Klipper, Robert W.
AU - Goins, Beth
AU - Phillips, William T.
PY - 1991
Y1 - 1991
N2 - Liposome-encapsulated hemoglobin (LEH) is an erythrocyte substitute that is a potential resuscitative fluid for the in vivo delivery of oxygen. We have noninvasively imaged radiolabeled LEH in vivo with technetium-99m (99mTc) to study the biodistribution in an anesthetized rabbit. Rabbits (2.5 kg, n = 8) were infused with 30 ml of LEH (200 mg of phospholipid, 2.5 g of hemoglobin per kg of body weight) and imaged with a γ camera continuously for 2 hr. At 20 hr postinfusion, the animals were imaged again and sacrificed; the organs were weighed and their radioactivity was determined for autopsy organ distribution. Organ uptake from the images was corrected for organ-associated blood pool, which was determined by infusion of 99mTc-labeled rabbit erythrocytes. Blood pool and decay-corrected biodistribution data reveal the kinetics of LEH distribution, with an initial rapid uptake by the liver, 8% at 30 min and 15% at 2 hr. The spleen accumulates less LEH initially, 3% at 30 min and 7% at 2 hr, with an apparent linear uptake of LEH over this time period. Image biodistribution data was also validated at 20 hr by tissue sampling. At 20 hr postinfusion, autopsy biodistribution data reveals approximately 42.6% of the total counts remaining in the blood, 15.4% in the liver, 18.1% in spleen, 3.2% in the lungs, 2.4% in muscle, 1.6% in urine, and trace levels in the kidney, brain, and heart (<1%). There is no evidence of hemoglobin release from LEH or kidney dysfunction (normal creatinine and blood urea nitrogen) at any time over the course of the study.
AB - Liposome-encapsulated hemoglobin (LEH) is an erythrocyte substitute that is a potential resuscitative fluid for the in vivo delivery of oxygen. We have noninvasively imaged radiolabeled LEH in vivo with technetium-99m (99mTc) to study the biodistribution in an anesthetized rabbit. Rabbits (2.5 kg, n = 8) were infused with 30 ml of LEH (200 mg of phospholipid, 2.5 g of hemoglobin per kg of body weight) and imaged with a γ camera continuously for 2 hr. At 20 hr postinfusion, the animals were imaged again and sacrificed; the organs were weighed and their radioactivity was determined for autopsy organ distribution. Organ uptake from the images was corrected for organ-associated blood pool, which was determined by infusion of 99mTc-labeled rabbit erythrocytes. Blood pool and decay-corrected biodistribution data reveal the kinetics of LEH distribution, with an initial rapid uptake by the liver, 8% at 30 min and 15% at 2 hr. The spleen accumulates less LEH initially, 3% at 30 min and 7% at 2 hr, with an apparent linear uptake of LEH over this time period. Image biodistribution data was also validated at 20 hr by tissue sampling. At 20 hr postinfusion, autopsy biodistribution data reveals approximately 42.6% of the total counts remaining in the blood, 15.4% in the liver, 18.1% in spleen, 3.2% in the lungs, 2.4% in muscle, 1.6% in urine, and trace levels in the kidney, brain, and heart (<1%). There is no evidence of hemoglobin release from LEH or kidney dysfunction (normal creatinine and blood urea nitrogen) at any time over the course of the study.
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U2 - 10.1073/pnas.88.23.10976
DO - 10.1073/pnas.88.23.10976
M3 - Article
C2 - 1961766
AN - SCOPUS:0025719010
VL - 88
SP - 10976
EP - 10980
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 23
ER -