Investigation of hypothermosol® as a delivery medium for cardiomyocyte progenitor cells

Cell preservation is an important issue in cell therapy trials. Cell growth rescue after thawing is an important consideration to avoid functional impairment or cell growth aberrations. PharmaCell participates in the Dutch Bio-Medical Materials program SmartCare that investigates the potential of cardiomyocyte progenitor cells (CMPCs) on bioactive microtissues for heart tissue regeneration. PharmaCell investigated the use of HypoThermosol® (BioLife solutions) to deliver cells of both fetal and adult origin for in vivo trials that would preserve these cells from the time of harvesting, preparation and transportation to the time of surgery. Cell number, viability, morphology and cell marker expression (FACS) were tested at different time points (0, 4, 8, 24, 48, 72 hrs). In addition, cells were grown after 72 or 96 h suspension in HypoThermosol® to test if their proliferative capacity was maintained. Cell numbers remained stable for both cell types. A modest (15% decrease) in cell viability was noted for fetal cells (after 96hrs) and 16% (after 72 hrs) for the adult cells. Protein expression in fetal cells remained within our specifications for cardiac markers NKX2.5, Gata-4, α-Actinin, while adult cells presented a substantial decrease in α-Actinin after 48hrs. Both type of cells were able to proliferate after HypoThermosol® exposure, but their population doubling times increased. The results support the use of HypoThermosol® as a preservation medium for fresh cells and addresses differences between CMPCs of different origins. This research forms part of the Project P1.04 SMARTCARE of the research program of the BioMedical Materials institute, co-funded by the Dutch Ministry of Economic Affairs. The financial contribution of the Netherlands Heart Foundation is gratefully acknowledged.