Retrovirus-Mediated Herpes Simplex Virus Thymidine Kinase Gene Therapy for the Prevention of Stenosis in Rat Carotid Artery Injury Model

Kim, Dong Woon; Kim, Young Gyu; Oh, Tae Geun; Cho, Myeong Chan; Kim, Seung Taik

Abstract

BACKGROUND
Herpes simplex virus thymidine kinase (HSVtk) phosphorylates the prodrug ganciclovir to a nucleoside analog that inhibits DNA synthesis, causing cell death. Neighbouring nontransfected cells may be affected through a 'bystander effect', thereby amplifying the antiproliferative actions. This study was carried out to determine whether retrovirus-mediated HSVtk gene therapy could reduce intimal hyperplasia and prevent stenosis following balloon injury of the rat carotid artery.
METHODS
A replication-defective recombinant retroviral vector containing HSVtk cDNA (LtkSN) was constructed. Cultured primary rat smooth muscle cells (SMCs) infected with this vector (SMC/LtkSN) were transplanted to the balloon injured rat right carotid artery. One week after transplantation, HSVtk gene therapy group was administered a 2-week treatment of ganciclovir (30 mg/kg/d). Three weeks after balloon injury and SMC/LtkSN transplantation, carotid arteriography was performed and carotid arteries were perfusion-fixed for histologic examination.
RESULTS
Carotid arteriographic evaluation comparing with the uninjured left carotid artery showed that the mean luminal diameter of HSVtk gene therapy group (n=5, 85+/-3%) was significantly larger than that of balloon injury only group (n=5, 65+/-5%). The neointimal mass of HSVtk gene therapy group was less than that of balloon injury only group. SMC/LtkSN transplantation without ganciclovir treatment group (n=3) showed asymmetric intimal proliferation probably because of gravitational pooling of seeding. There were inflammatory cell infiltrations at the gravity dependent portion of HSVtk gene therapy group.
CONCLUSION
Retrovirus-mediated HSVtk gene therapy following balloon injury of the rat carotid artery reduced neointimal expansion and arteriographic stenosis.