Abstract 16485: Reconstitution of Aged Bone Marrow With Young Sca-1 Cell Rejuvenates the Aged Heart

Aims: The mechanism responsible for the limited rejuvenation potential of the aged heart remain elusive. We previously reported that Sca-1+ cells are a key BM cell type for the rejuvenation of the aged heart. The present study was designated to identify the molecular mechanism of the aged heart rejuvenation by BM Sca-1+ cells. Methods and Results: BM Sca-1+ or Sca-1- cells from young (2-3 mos old) or aged (18-19 mos old) GFP transgenic mice were transplanted into lethally irradiated aged mice to generate 4 groups of chimeras: Young Sca-1+ /Sca-1- and old Sca-1+/ Sca-1- respectively. Four months after BM rejuvenation, the expression of rejuvenation-related genes (BMI1, Chromobox 8, PNUTS, Sirtuin 1[Sirt1], Sirt2, Sirt6) and proteins (Cyclin-dependent kinase 2 [Cdk2],Cdk4) was increased whereas the expression of senescence-related genes (P16, P19, P27) and proteins (p16, p27) was decreased in the Sca-1+ chimeric hearts, especially in the young Sca-1+ group (Pu003c0.05). Telomerase activity was increased (107.9±...