The aortic valve after heart transplantation

Pathology Of Explanted Cryopreserved Allograft Heart Valves: Comparison With Aortic Valves From Orthotopic Heart Transplants

“…The present study shows that aortic valves from both short-term and long-term heart transplants have essentially normal gross and microscopic structure and intrinsic cellularity, in agreement with another recent report. 30 The valves we studied included those from patients with as many as 12 previous rejection episodes and from fatal myocardial rejection in which the allograft response had overwhelmed immunosuppression. Valves from transplants were also free of degenerative features, including calcification and the intimal thickening characteristic of graft arteriosclerosis.…”

Immune Privilege of Heart Valves

“…Contrary to organ transplants which require immediate and lifelong immunosuppression, allograft heart valve implants display long-term functionality without HLA and ABO matching and without immunosuppression of the recipient (26). Furthermore, even transplanted hearts that have failed due to rejection have been shown to have functionally and structurally intact semilunar valves, suggesting valves may be immunologically distinct from heart tissue (27)(28)(29). Several other studies have noted the aortic valve as a possible immune privileged site (30)(31)(32).…”

Cryopreservation and Freeze-Drying Protocols

“…It is relevant to vitrification in the sense that sufficiently concentrated cytoplasm undergoes a glass transition that contributes to the survival of organisms, cells, or seeds that are adapted to or prepared for preservation by drying [57,58]. Although it is of considerable potential applied and ecological significance [57][58][59][60], this chapter focuses primarily on low-temperature vitrification rather than on high-temperature anhydrobiosis or aestivation.…”

“…In the range of super-zero temperatures (e.g., 0-37 ∘ C) utilization of this model has been carried out in a very wide range of cell types [5,[51][52][53][54][55][56][57][58][59]. There are some criticisms of this model, however, including that there are other larger temperature dependent causes for changing parameter values [60-62], including membrane phase transitions [63].…”

“…Panel reactive antibody analysis was performed using serum obtained pre-implant and 10 and 20 weeks post implant. None of the Calcium-specifi c mineralization occurring in aortic allografts was quantifi ed using atomic absorption spectroscopy [ 59 ]. There were no signifi cant differences animals demonstrated MHC Class I antibodies.…”