Endothelium-dependent relaxant responses to bradykinin of cryostored  human coronary arteries were markedly diminished by 70%. 

This was reflected morphologically by marked endothelial denudation in cryostored arteries. After cryopreservation at least 50% of the endothelium was detached [19] 




In human internal mammary arteries prefreezing removal of surplus cryomedium immediately before starting the freezing process did not change the contractile responses but improved considerably the endothelium-dependent relaxation to acetylcholine [24].  



Scanning electron micrographs of the endothelium of human IMAs performed after the organ bath experiments reflected the functional findings. In unfrozen arteries the endothelial layer was well preserved. 

Freezing without surrounding medium resulted in well-preserved endothelium. 

When frozen in medium exfoliation of the endothelium was significant. Areas of de-endothelialization and exposure of the subendothelial surface were most extensive [24].