Protein-containing lipososomes and their distribution among the organs

A comparative study was made of the distribution of creatine phosphokinase (CPK) among the organs of rats after its intravenous injection of the enzyme in liposomes and in the unencapsulated state. Uptake of CPK-¹²⁵I was found to be 5.5 times higher in the liver and spleen after lyosomal injection than after injection of the free enzyme. In the kidneys and lungs on the first day the enzyme level was higher after free injection, on account of its rapid elimination and high blood level. In all organs the enzyme remained detectable for much longer (from 4 to 6 days) in the tissues, whereas after free injection of the label none could be found after 24 h. The intracellular localization of the label above vacuoles of hepatocytes when the enzyme was injected in liposomes, and the absence of both label and vacuoles after free injection of the enzyme, were demonstrated autoradiographically. The enzyme activity was found to be preserved after liposomal injection in liver homogenates. Prospects for the use of liposomes as a transport medium for supplying proteins for the treatment of hereditary diseases are discussed.Academic Group of Corresponding Member of the Academy of Medical Sciences of the USSR Professor E. F. Davidenkova, Laboratory of Experimental Histology, Research Institute of Experimental Medicine, Leningrad. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 6, pp. 673–675, June, 1978.