Functional and structural assessment of retinal sheet allograft transplantation in feline hereditary retinal degeneration.
OBJECTIVE
To investigate whether sheets of fetal retinal allografts can integrate into the dystrophic Abyssinian cat retina with progressive rod cone degeneration.


METHODS
Fetal retinal sheets (cat gestational day 42), incubated with BDNF microspheres, were transplanted to the subretinal space of four cats at an early disease stage. Cats were studied by fundus examinations, bilateral full-field flash ERGs, and indocyanine green and fluorescein angiograms up to 4 months following surgery. E42 donor and transplanted eyes were analyzed by histology and immunohistochemistry for retinal markers.


RESULTS
Funduscopy and angiography showed good integration of the transplants in two of four cats, including extension of host blood vessels into the transplant and some scarring in the host. In these two, transplants were found in the subretinal space with laminated areas, with photoreceptor outer segments in normal contacts with the host retinal pigment epithelium. In some areas, transplants appeared to be well-integrated within the host neural retina. Neither of these two cats showed functional improvement in ERGs. In the other two cats, only remnants of donor tissue were left. Transplants stained for all investigated cellular markers. No PKC immunoreactivity was detected in the fetal donor retina at E42, but developed in the 4-month-old grafts.


CONCLUSIONS
Fetal sheet transplants can integrate well within a degenerating cat retina and develop good lamination of photoreceptors. Functional improvement was not demonstrated by ERG in cats with well-laminated grafts. Transplants need to be further evaluated in cat host retinas with a more advanced retinal degeneration using longer follow-up times.
Seiler
Magdalene J
MJ
Department of Ophthalmology, Keck School of Medicine, University of South California, Los Angeles, CA, USA.
Aramant
Robert B
RB
Seeliger
Mathias W
MW
Bragadottir
Ragnheidur
R
Mahoney
Melissa
M
Narfstrom
Kristina
K
D000818:Animals; D002371:Cat Diseases / Q000235:genetics / Q000601:surgery*; D002415:Cats; D016332:Fetal Tissue Transplantation; D020022:Genetic Predisposition to Disease; D006085:Graft Survival; D012160:Retina / Q000473:pathology / Q000637:transplantation*; D012162:Retinal Degeneration / Q000235:genetics / Q000662:veterinary*