[Retinitis pigmentosa--clinical, genetic and pathophysiologic aspects]

Preservation of photoreceptors in dystrophic RCS rats following allo- and xenotransplantation of IPE cells

PURPOSE

To examine whether iris pigment epithelial (IPE) cells transplanted into the subretinal space of Royal College of Surgeons (RCS) rats have the ability to rescue photoreceptors.

METHODS

Rat IPE (rIPE) or human IPE (hIPE) cells were transplanted subretinally in 23-day-old RCS rats. Sham injection and transplantation of ARPE-19 cells served as controls. After 12 weeks, eyes were evaluated for photoreceptor survival by morphometric analysis and electron microscopy.

RESULTS

Morphometric analysis showed photoreceptor rescue in all transplanted and sham-injected animals (number of photoreceptors/300 microm retina+/-sd: rIPE 41.67 +/- 28; hIPE 29.50 +/- 16; ARPE-19 36.12 +/- 21; sham 16.56 +/- 6) compared to age-matched, control rats (number of photoreceptors/300 microm retina+/-sd: 9.71 +/- 4). Photoreceptor rescue was prominent in IPE cell-transplanted rats and was significantly greater than sham-injected eyes (p = 0.02 for rIPE and p = 0.04 for hIPE).

CONCLUSION

Since IPE cells transplanted into the subretinal space have the ability to rescue photoreceptors from degeneration in the RCS rat without any harmful effects, IPE cells may represent an ideal cell to genetically modify and thus carry essential genetic information for the repair of defects in the subretinal space.

Perspectives on the management of the complications of senile retinoschisis

PURPOSE

To evaluate various published views regarding the management of complications of senile retinoschisis.

METHODS

To analyze and compare various reports of studies of natural history and prognosis, and comparative risks of non-intervention vs prophylactic surgery.

RESULTS

Although a number of recent techniques for treatment or prevention of complications of senile retinoschisis have been reported with generally satisfactory results, the numbers of cases have been small and no consensus can be said to have been achieved as to superiority of method. When compared to the extremely low likelihood of the natural occurrence of complications such as posterior progression to involve the macula, or of the development of progressive clinical retinal detachment, as well as the occurrence of risks of treatment, it appears preferable to postpone treatment until these complications actually make their appearance.

CONCLUSIONS

It is recommended that in cases of retinoschisis either without or with breaks, or retinoschisis with localized 'schisis-detachment', that prophylactic treatment be withheld except in a very few exceptional cases. In all cases of progressive, symptomatic rhegmatogenous retinal detachment however, prompt surgical treatment should be carried out.