Gene Therapy Using Retroviral Vector Containing Rat Erythropoietin / 대한혈액학회지

ABSTRACT

BACKGROUND: Erythropoietin (EPO) is crucial to red blood cell regulation. Since the recombinant EPO was clinically available, it has been widely used in the treatment of anemia associated with disorders such as chronic renal failure, cancer and acquired immunodeficiency syndrome. Ex vivo therapy of recombinant EPO, however, requires large dose and frequent administration, which gives a financial impact to the patients. To make in vivo delivery system of EPO will be valuable to the patients who need EPO for a long time. METHODS: We have tried to make an in vivo EPO delivery system using transduced vascular smooth muscle cells with EPO gene in a rat model. Recombinant retroviral vector containing EPO gene was made employing LXSN and LNFX plasmid. Recombinant retrovirus was produced from PA317 packaging cell. Infection of the vascular smooth muscle cells with the virus and selection with G418 was done in vitro. These transduced cells were transplanted to the balloon-injured carotid artery, and hemoglobin and hematocrit as well as reticulocyte were measured in sequence. RESULTS: The virus titer was ten times greater in case of LNFEp than LEpSN, whereas EPO production from infected vascular smooth muscle cell was similar between LEpSN and LNFEp vectors (67mU/106cell/day and 68mU/106cell/day, respectively). The levels of hemoglobin and hematocrit increased gradually after transplantation of the transduced cells with LEpSN, reached to peak after 3 weeks (18.4+/-0.63gm/dL in case of hemoglobin and 50.7+/-0.62% in case of hematocrit) and remained thereafter. The percentage of reticulocyte was elevated from the 4th day to the 14th day after transplantation and returned to normal. CONCLUSION: The low dose required to the elevation of RBC mass and long sustained effect of transduced smooth muscle cell could make this gene therapy feasible to the clinical conditions.