Telomerase activity in rat liver allografts

Background Telomerase activity in grafts may be involved in the alteration of cellular senescence after transplantation or its relevant immunological events. Methods. At the age of 20 weeks, donor livers harvested from DA (RT1(a)) we re orthotopically transplanted into PVG (RTIc) or LEW (RT1(1)) rats. Rats h aving undergone orthotopic liver transplantation (OLT; DA-PVG) naturally ov ercome rejection, whereas all OLT (DA-LEW) rats die from acute rejection wi thin 14 days. Telomerase activity in liver allografts was measured at vario us intervals post OLT. Results. At day 7 when the most severe rejection episode was observed in OL T (DA-LEW) and OLT (DA-PVG), the telomerase activity was significantly high er than in syngeneic OLT (DA-DA) rats, in which no rejection occurred. Telo merase activity in tolerogenic OLT (DA-PVG) livers remained elevated for at least 2 months. Conclusion. These results suggest that telomerase activity in allogeneic OL T livers may reflect regenerating hepatocytes or activation of lymphocytes and/or hematopoietic stem cells, associated with rejection or tolerance.