Antigenicity and fate of cellular components of heart valve allografts

Yankah, A. C.; Wottge, H.-U.; Müller-Ruchholtz, W

doi:10.1007/978-3-642-72420-6_16

Cited by 10 publications

(9 citation statements)

References 7 publications

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“…AVA tissue was harvested as previously described 8, 16. In brief, under general anesthesia (isoflorane) and using an operating microscope a midline laparotomy was made, the animal was exsanguinated by transecting the inferior vena cava, and the incision was then extended as a median sternotomy.…”

Section: Methodsmentioning

confidence: 99%

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Comparison of aortic valve allograft decellularization techniques in the rat

Meyer

Chiu

Churchill

et al. 2006

J Biomedical Materials Res

151

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Rodent models have been essential to understanding the immune-mediated failure of aortic valve allografts (AVAs). Decellularization has been proposed to reduce the immunogenicity of AVAs. The objective of this study was to determine the most effective method to decellularize AVAs for use in a rat model. Three different decellularization techniques were compared in Lewis aortic valves. Detergent decellularization involved a series of hypotonic and hypertonic Tris buffers at 4 degrees C for 48 h/buffer containing 0.5% Triton X-100 followed by a 72 h washout in phosphate-buffered saline. Osmotic decellularization was performed in similar manner to the detergent-based technique except without the addition of Triton X-100. Enzymatic decellularization consisted of trypsin/EDTA at 37 degrees C for 48 h. Assessment was performed with light microscopy (H&E, Movat's pentachrome), immunohistochemistry for residual cellular elements, and hydroxyproline assays. Detergent-based methodology effected near-complete decellularization of both the leaflets and aortic wall in addition to preservation of the extracellular matrix (ECM). Osmotic lysis was associated with preservation of ECM and moderate decellularization. Enzymatic decellularization resulted in complete decellularization but extensive degeneration and fragmentation of the ECM. When implanted into the infrarenal aorta of allogeneic rats for 1 week, valves decellularized with detergent-based and osmotic methodology failed to stimulate an allogeneic immune response as evidenced by an absence of T cell infiltrates. Osmotic lysis protocols with low dose detergent appear to be most effective at both removing antigenic cellular elements and preserving ECM.

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Section: Methodsmentioning

confidence: 99%

“…Brown Norway rat (150 g) AVAs were implanted into recipient Lewis rats (250 g) using an infrarenal implantation model 8, 16. Aortic valves were harvested under general anesthesia as described above.…”

Section: Methodsmentioning

confidence: 99%

Comparison of aortic valve allograft decellularization techniques in the rat

Meyer

Chiu

Churchill

et al. 2006

J Biomedical Materials Res

151

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“…The technique of aortic valve allograft transplantation was performed as first described by Yankah et al 16 An intraperitoneal injection of 65 mg/kg sodium pentobarbital was used to anesthetize the rats.…”

Section: Aortic Valve Allograft Implantationmentioning

confidence: 99%

Cryopreservation of Rat Aortic Valves Results in Increased Structural Failure

Légaré

Lee²

2000

Circulation

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Background-The cause of valve allograft failure is most likely multifactorial and may include mechanical, immunological, and other factors. Cryopreservation of these valves is often used to extend storage times. However, there has been considerable confusion as to the effects of cryopreservation on valve durability. Our objective was to determine the effects of cryopreservation on histopathological changes in rat aortic valve grafts. Methods and Results-Syngeneic rat aortic valve grafts (Lewis to Lewis; nϭ24) and allogeneic rat aortic valve grafts (Brown Norway to Lewis; nϭ24) were implanted infrarenally, either fresh or after cryopreservation. At 7, 14, and 28 days, the valves were explanted, and histological and immunohistochemical examinations were performed in a blinded fashion. Fresh syngeneic graft leaflets retained their normal structure for the 28-day period of observation. Cryopreserved syngeneic grafts showed retrovalvar thrombus formation, with leaflet destruction at 7, 14, and 28 days. Fresh allogeneic graft leaflets showed significant leaflet thickening and progressive destruction at 14 and 28 days. Cryopreserved allogeneic grafts had evidence of retrovalvar thrombus formation with leaflet destruction at 7, 14, and 28 days. Cryopreserved syngeneic grafts resulted in significant infiltration of mononuclear (ED1 ϩ ) cells not seen with fresh syngeneic grafts but similar to fresh allogeneic grafts. All allogeneic grafts resulted in significant infiltration of T-lymphocytes (CD3 ϩ , CD8 ϩ , CD43 ϩ ). Conclusions-Cryopreservation appears to predispose syngeneic and allogeneic rat aortic valve leaflets to accelerated injury and destruction.

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“…Evidence suggesting an immunologic basis has been presented by numerous authors. [12][13][14][15][16] This study describes the pathologic changes in rats, over time, after transplantation of syngeneic versus allogeneic and fresh versus cryopresetved valves and identifies changes indicative of rejection. These changes could be in the form of either an acute or chronic rejection process.…”

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confidence: 99%