Structural integrity of collagen and elastin in SynerGraft® decellularized-cryopreserved human heart valves

SynerGraft® (SG) decellularized-cryopreserved cardiac valve allografts have been developed to provide a valve replacement option that has reduced antigenicity, retained structural integrity, and the ability to be stored long-term until needed for implantation. However, it is critical to ensure that both the SG processing and cryopreservation of these allografts do not detrimentally affect the extracellular matrix architecture within the tissue. This study evaluates the effects of SG decellularization and subsequent cryopreservation on the extracellular matrix integrity of allograft heart valves. Human aortic and pulmonary valves were trisected, with one-third of each either left fresh (no further processing after dissection), decellularized, or decellularized and cryopreserved. Two-photon laser scanning confocal microscopy was used to visualize collagen and elastin in leaflets and conduits. The optimized percent laser transmission (OPLT) required for full dynamic range imaging of each site was determined, and changes in OPLT were used to infer changes in collagen and elastin signal intensity. Collagen fiber crimp period and collagen and elastin fiber diameter were measured in leaflet tissue. Statistically significant differences in OPLT and the dimensional characteristics of collagen and elastin in study groups were determined through single factor ANOVA. The majority of donor-aggregated average OPLT observations showed no statistically significant differences among all groups, indicating no difference in collagen or elastin signal strength. Morphometric analysis of collagen and elastin fibers revealed no significant alterations in treated leaflet tissues relative to fresh tissues. Collagen and elastin structural integrity within allograft heart valves are maintained through SynerGraft® decellularization and subsequent cryopreservation.