The present invention provides a system and method of maintaining and/or increasing cell viability by downregulating cellular metabolic rate under hypoxic conditions, wherein the availability of adenosine or derivatives thereof in the cell is increased and/or prolonged. The present invention also relates to a system and method of prolonging the survival of implanted cells that are under hypoxic condition until host neovascularization is achieved, wherein the availability of adenosine or derivatives thereof in the cell is increased and/or prolonged. The present invention also provides a system and method of maintaining and/or increasing cell viability by downregulating cellular metabolic rate under hypoxic conditions, wherein at least one purine metabolism enzyme inhibitor is applied to the cell.
