Platelet gel supernatant as a potential tool to repopulate acellular heart valves.
OBJECTIVE
The aim of this study was to repopulate decellularized heart valve matrices with ovine mesenchymal stem cells (oMSCs) by the use of platelet gel (PG) supernatant, a storage vehicle for growth factors.


METHODS
oMSCs were exposed to different concentrations of PG-released supernatant and cell proliferation was evaluated using the MTS assay. oMSC motility and invasiveness were assayed using a Boyden chamber. A quantitative sandwich enzyme immunoassay was used to examine amounts of bFGF and TGF-β1 in the PG supernatant. Repopulation of acellular heart valve matrices was stimulated by seeding matrices with oMSCs supplemented with the PG supernatant.


RESULTS
The most significant increase in proliferation induced by PG supernatant appeared at 1 × 10(5) plts/ml concentration. Higher concentrations evoked reduction of the stimulatory process. oMSC motility was most significantly stimulated at 1 × 10(6) plts/ml. Stimulating invasiveness of oMSCs needed the much higher concentration of 2 × 10(6) plts/ml. Immunoassays revealed that sheep PG supernatant contains 184.8 pg/ml bFGF and 60.5 ng/ml TGF-β1. Moreover, repopulation of acellular heart valve matrices was significantly enhanced by PG supernatant addition and resulted in upregulation of the myofibroblast marker alpha-smooth muscle actin.


CONCLUSIONS
Growth factors released from platelets had the potential to induce cell repopulation in a heart valve tissue engineering procedure, through stimulation of mesenchymal stem-cell migration and invasion.
Department of Basic Medical Sciences, Ghent University, Ghent, Belgium. pamela.somers@ugent.be
P
P
Somers
L
L
Robyns
E
E
Nollet
F
F
De Somer
M
M
Cornelissen
H
H
Thierens
G
G
Van Nooten
D000818:Animals; D001792:Blood Platelets; D049109:Cell Proliferation; D003470:Culture Media; D005260:Female; D005782:Gels; D006351:Heart Valves / Q000166:cytology*; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D059630:Mesenchymal Stem Cells / Q000166:cytology; D012756:Sheep
D003470:Culture Media; D005782:Gels