Is the long term degeneration only due to physiological aging and calcification or is there a component of host-versus-graft reaction?
Some links related to topic are posted below.
http://www.ncbi.nlm.nih.gov/pubmed/24700229
http://www.ncbi.nlm.nih.gov/pubmed/27026750
http://www.ncbi.nlm.nih.gov/pubmed/24618389
hi,
as I know, most of the time there would be immune response for allograft transplants which could happen very slowly.
Definitely immunological component, although different preservation techniques may decrease immunogeneity. We did a study in rats quite a few years ago: (I unfortunately do not have full text access to this journal). BW
J Heart Valve Dis. 2002 May;11(3):326-34.
Frequencies of donor-reactive helper T lymphocytes correlate with rejection of aortic valve allografts in rats.
Dor FJ1, Oei FB, Vaessen LM, Marquet RL, Bogers AJ, Weimar W.
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Abstract
BACKGROUND AND AIMS OF THE STUDY:
Human valve allografts are commonly used in cardiac surgery for congenital and acquired valve diseases. Particularly in the pediatric population, these allografts are prone to fail in the long term, and require replacement. In part, this failure may be due to immunological phenomena. The frequency of helper T lymphocytes (HTLf) measured in peripheral blood and spleen serves as a parameter for acute rejection in organ transplantation. The value of this parameter in valve transplantation was studied using the 'Rotterdam' implantation model in rats.
METHODS:
HTLf were determined in peripheral blood and spleen at seven and 21 days after allogeneic (WAG-->DA) and syngeneic (DA-->DA) implantation of an aortic valved conduit. Valve competence was tested pre-implantation, at days 7 and 21 after implantation, and after explantation using a retrograde saline injection. Explanted valves were examined histologically.
RESULTS:
At seven days after allogeneic valve transplantation, HTLf in spleen (median 71/10(6)), but not in peripheral blood (median 26/106) were significantly elevated. At 21 days after allogeneic transplantation, a significant increase in HTLf was seen in both peripheral blood (median 10(9)/10(6)) and spleen (median 92/10(6)). All five (100%) syngeneic grafts and five of seven (71%) allografts were competent at day 7. At day 21, all five syngeneic grafts (100%) and zero allografts (0%) remained competent (p = 0.01). Histologically, mononuclear cell infiltration into the allogeneic valve leaflets and in the vascular wall was observed at day 7. At day 21, valve leaflets appeared to be acellular and deformed. All syngeneic valve grafts retained normal morphology.
CONCLUSION:
After aortic valve allografting in the rat, HTLf correlate with valve dysfunction and histopathological signs of rejection. Therefore, HTLf-analysis may be a useful tool in monitoring the cellular immune response as an indicator for early graft dysfunction due to rejection in clinical valve transplantation.
Many interesting data exists about the role humoral rejection directed toward alpha-Gal epitope in heart valve bioprostheses.
Xenotransplantation. 2013 Jul-Aug;20(4):252-61. doi: 10.1111/xen.12044. Epub 2013 Jul 19.
First quantification of alpha-Gal epitope in current glutaraldehyde-fixed heart valve bioprostheses.
Naso F1, Gandaglia A, Bottio T, Tarzia V, Nottle MB, d'Apice AJ, Cowan PJ, Cozzi E, Galli C, Lagutina I, Lazzari G, Iop L, Spina M, Gerosa G.
Thorac Cardiovasc Surg. 2009 Jun;57(4):191-5. doi: 10.1055/s-0029-1185395. Epub 2009 May 20.
Alpha-Gal specific IgG immune response after implantation of bioprostheses.
Mangold A1, Szerafin T, Hoetzenecker K, Hacker S, Lichtenauer M, Niederpold T, Nickl S, Dworschak M, Blumer R, Auer J, Ankersmit HJ.
Degeneration is a known problem with cryopreserved arterial vascular allografts, such that use in practice tends to be restricted to patients in whom there are no other options for vascular reconstruction.
This article provides a concise summary-
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4481033/
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