Mg. Hazekamp et al., IN-SITU HYBRIDIZATION - A NEW TECHNIQUE TO DETERMINE THE ORIGIN OF FIBROBLASTS IN CRYOPRESERVED AORTIC HOMOGRAFT VALVE EXPLANTS, Journal of thoracic and cardiovascular surgery, 110(1), 1995, pp. 248-257
Tissue degeneration reduces the durability of cryopreserved homografts
. Earlier studies indicated that the presence of fibroblasts in homogr
aft leaflets may contribute to increased valve longevity, These fibrob
lasts may be of recipient origin or represent surviving donor cells. W
e developed a method, based on in situ hybridization, to determine the
origin of fibroblasts in homograft explants. In young pigs we perform
ed aortic valve replacement with a cryopreserved porcine aortic homogr
aft, A male homograft was implanted in a female pig, whereas two male
recipients received a female homograft. After 3 to 4 months the homogr
afts were explanted, Frozen sections were made and alternately examine
d with hematoxylin-eosin staining and in situ hybridization. With a bi
otinylated porcine Y chromosome-specific deoxyribonucleic acid probe,
male fibroblasts could be clearly distinguished from female fibroblast
s. In all leaflets we observed both donor and recipient fibroblasts. T
he distribution of these populations was marked in schematic drawings.
Recipient fibroblasts mostly spread onto the leaflet surface but also
penetrated the leaflet tissue. Remaining donor fibroblasts did not sh
ow morphologic signs of decreased viability on hematoxylin-eosin stain
ing. In situ hybridization may become a useful technique in homograft
research, In this porcine model, the fibroblasts in the aortic homogra
ft explants were of both donor and recipient origin.