ANGIOMYOGENESIS USING HUMAN MYOBLASTS CARRYING HVEGF165 FOR IMPROVED MYOCARDIAL PERFORMANCE
L. Ye1, H. Haider1, P.K. Law2, M. Teh3, T. Chua4, P. Wong4, Y.L. Lim4, E.K.W. Sim1, 1 Cardiothoracic Surgery, National University Hospital, Singapore, 2 Cell Transplantation Inc., Science Park-II, Singapore, 3 Department of Pathology, National University Hospital, Singapore, 4 National Heart Centre, Singapore General Hospital, Singapore.
Human myoblast (HM) transplantation has been used for the repair of damaged myocardium in animal models and human phase-I studies1,2. We hypothesize that HM expressing hVEGF165 would have the potential of concurrent angiogenesis and myogenesis in a failing heart. Human myoblasts transduced with retroviral and adenoviral vectors carrying lac-z and hVEGF165 genes respectively, were characterized for VEGF165 transduction and expression efficiency by immunostaining, ELISA, Immunoblotting and RT-PCR. The transduction efficiency for lac-z and VEGF165 was 75-80% and >95% respectively and the cells continued to secrete VEGF165 for longer than 18 days, significantly higher (37± 3ng/ml) than non-transduced HM (200 ±30 pg/ml). A porcine heart model of infarction was created by left circumflex artery ligation in 8 female swine, control n= 3 and cell transplanted n= 5. Angiography was performed to ensure complete occlusion of the blood vessel. Four weeks later, 5 ml basal DMEM without or with 3x108 HM carrying VEGF165 and lac-z genes, with >95% cell viability, were injected into the left ventricle endomyocardially. The animals were maintained on cyclosporine (5mg/kg body weight) for six weeks post cell transplantation. The heart function was confirmed prior to and 6 weeks after cell transplantation with Tc99m-MIBI SPECT scanning showed 44% improvement. Heart was explanted between 6 and 12 weeks post transplantation. Histochemical studies revealed extensive lac-z expressing donor cells in the host tissue in and around the infarct. The vascular density (mean ± SEM) counted in an average of 12 low power fields (x200) in control animals hearts was (4.18± 0.42) as compared to the cell transplanted group (28.31 ±1.84). We conclude that HM are potential therapeutic transgene carriers for the myocardium for concurrent angiogenesis and myogenesis.
(1) Taylor DA, Atkin BZ, Hungspecugs P, Jones TR, Reedy MC, Hutcheson KA, Glower DD, Kraus WE. Nature Medicine. 1998;4:929-933.
(2) Menache P, Hagege AA, Scorcin M, Pouzet B, Desnos M, Duboc D, Schwartz K, Vilquin JM, Marolleau JP. Lancet. 2001;357;279-280.
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