Failure to prolong rat renal allograft survival time by photochemical donor kidney pretreatment during hypothermic pulsatile kidney preservation.

Systemic photochemical pretreatment of a rat kidney donor with the photosensitizer 8-methoxypsoralen (8-MOP; 0.06 mg/kg intravenously, 10 min before graft removal) plus ex vivo longwave ultraviolet (UVA) irradiation of the kidney graft during simple hypothermic storage significantly prolonged survival time in allogeneic recipients. In contrast to these results, the present use of UVA irradiation during hypothermic pulsatile kidney perfusion using Euro-Collins solution containing 8-MOP (0.06 mg/ml) did not prolong graft survival compared with untreated controls. Systemic application of 8-MOP to the kidney donor may be necessary for effective action of the combined photochemical treatment as a method of immunoalteration. The extended UVA irradiation time and the local use of 8-MOP in the preservation fluid had no effect on graft survival possibly because of inadequate tissue distribution of 8-MOP during both hypothermia and perfusion.