Effect of Cryopreservation of Human Heart Cells on Cell Proliferation

Abstract

Preservation is essential for successful cell transplantation. 1) Control group (n=13); Cells isolated from human right atrial tissues were cultured for 15 days. 2) Cell-cryopreservation (C. P.) group (n=23), Tissue-C. P. group (n=29); Human heart cells and minced tissues were cryopreserved in freezing medium containing 70% IMDM, 20% FBS, and 10% DMSO at a rate of 1°C/min. to -80°C by a programmed freezer and stored in liquid nitrogen (-196°C) for 1 week. After cryapreservation, the tissues and cells were thawed rapidly at 37°C. The cells, cryopreserved cells and cells isolated from cryopreserved tissues were cultured as passage 1, 2, and 3 for 15 days each. Cell proliferation was compared with a control group by determining growth curves, and 2-day proliferation rates. A growth factor, biochemical features and cell cycle were measured pre and post-cryopreservation. The cryopreserved group proliferated much more than the control group within 15 days at passage 1, 2, and 3 (1.7, 2.1, and 3.1 times, p<0.0001) respectively. The 2-day proliferation rates of cryopreservation group were higher than the control group in 15 days (p<0.05). The bFGF release after cryopreservation was on average 46.8 and 6.8 times greater than before cryopreservation for the Cell-C. P. and Tissue-C. P. groups, respectively. The TGF-β1 release was also accelerated by cryopreservation (Cell-C.P. group: 1.78 times, Tissue-C. P. group: 1.45 times in average) after cryopreservation. The cell cycle of human heart cells shifted to G2+M from the G1+G0 period by cryopreservation. Human atrial tissues and cells can be cultured and cryopreserved. The cryopreserved cells and cells isolated from cryopreserved tissue proliferate much more than non-cryopreserved cells at all cell ages. Cryopreservation enables human tissues and cells to proliferate more because of the greater release of growth factors and changing cell cycle.