Abstract
Abstract: :
Purpose: To establish the morphology of full-thickness neuroretinal grafts, transplanted to hosts with degenerative photoreceptor disease. Methods: Eighteen Pro 347 Leu rhodopsin transgenic pigs, aged 68-71 days, in one eye received a 2x3 mm neuroretinal sheet from a neonatal normal pig. Following vitrectomy and retinotomy with bleb formation, the grafts were positioned inside the bleb between the host neuroretina and retinal pigment epithelium (RPE). Proper polarity was kept throughout the procedure, and the grafts were flattened using gentle pressure on the overlying host retina. After a survival time of 4 months, eye specimens were studied in the light microscope. Results: One eye developed endophthalmitis in the immediate postoperative period and was terminated. Laminated grafts were found in 12 of the remaining 17 eyes. Two grafts developed into rosettes, and in three eyes, the graft could not be found. The laminated grafts measured from 1.0 - 3.3 mm, and displayed well developed photoreceptors with outer segments apposed to the host RPE. Inner layers of the graft had degenerated, leaving only parts of the inner nuclear layer. Both eyes of the hosts displayed a reduction of photoreceptor cells to 2 - 3 rows of cells in the outer nuclear layer in most of the retina. Photoreceptor degeneration of the host was in most cases not increased in the graft area, but in areas where no host photoreceptors remained, fusion of graft and host retinal layers was evident. Conclusion: Full-thickness grafts can be transplanted into a host featuring photoreceptor degeneration. The transplantation procedure, is relatively atraumatic to both graft and host tissue and does not provoke any adverse immune response. In the majority of cases, the grafts display well developed photoreceptors, organized as in the normal retina. Inner retinal layers are less pronounced, and as a result, the grafts integrate well with the host inner retinal layers when host photoreceptors are completely absent.
Keywords: 607 transplantation • 554 retina