The effect of lyophilization on graft acceptance in experimental xenotransplantation using porcine cornea.
ABSTRACT The immunogenicity of lyophilized porcine cornea is unknown. The purpose of this study was to examine the possibility of using lyophilized porcine cornea as a substrate for ocular surface reconstruction. A porcine cornea stromal button was freeze-dried and vacuum-packed. Lyophilized and fresh porcine corneas were examined histologically, and then implanted into intrastromal pockets in live rat corneas. Cytokine concentrations in plasma and protein extracts from the corneal buttons of rats were measured using the fluorokine multianalyte profiling assay, and histologic examination was performed. Immunoreactivity to the alpha-gal epitope was not found in lyophilized porcine corneas, whereas it was found in several keratocytes in fresh porcine corneas. The median survival time of rat corneas receiving lyophilized porcine transplants was 28.0 days, significantly longer than the 14.0-day survival of rat corneas that received fresh porcine transplants (P < 0.05). CD45RO(+) and CD68(+) cells were observed in rejected corneas, and interleukin-2 and interferon-gamma were elevated in rat plasma and corneal tissue. The lyophilized porcine corneal stroma, which is devoid of alpha-gal epitope, is less antigenic, and may be a useful biomaterial for ocular surface reconstruction and corneal collagen supplementation.
- SourceAvailable from: Andrea J Braakhuis[show abstract] [hide abstract]
ABSTRACT: Nonvascularized xenograft rejection is T cell mediated, but is dependent on initial macrophage (Mphi) infiltration. We developed an i.p. transplant model to define the roles of Mphi and T cells in xenograft rejection. Nonobese diabetic or BALB/c mice were injected i.p. with xenogeneic, allogeneic, or syngeneic cells, and the responding cells in subsequent lavages were assessed by flow cytometry and adoptive transfer. Neutrophils and monocytes/elicited Mphi were rapidly recruited in response to xenogeneic pig (PK15 or spleen) cells and, to a significantly lesser extent, allogeneic cells. These innate responses preceded T cell infiltration and occurred in their absence in SCID mice. Syngeneic cells induced negligible neutrophil or Mphi responses. Neutrophils and Mphi induced by xenogeneic cells in SCID mice stimulated T cell recruitment after transfer to immunocompetent mice. T cells in turn were required for Mphi activation and xenogeneic cell rejection. Thus, Mphi harvested from immunocompetent but not SCID mice injected with xenogeneic cells expressed activation markers and rejected xenogeneic cells when transferred into SCID mice. These findings demonstrate the interdependent roles of Mphi and T cells in xenograft rejection. The requirement for Mphi reflects their ability to mount a rapid, local innate response that stimulates T cell recruitment and, having received T cell help, to act as direct effectors of rejection.The Journal of Immunology 03/2001; 166(3):2133-40. · 5.52 Impact Factor
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ABSTRACT: This report presents for the first time the results of carrying out epikeratophakia with tissue lathed at room temperature. Using an experimental model of epikeratophakia in the rabbit, we evaluated tissue handling techniques for the preparation of donor lenticules. Details of the technique are described and the in-vivo and histopathological findings reported.British Journal of Ophthalmology 06/1988; 72(5):354-60. · 2.73 Impact Factor
- Transplantation 01/1996; 61(5):763-771. · 3.78 Impact Factor