Selected predictors of apoptosis in retinitis pigmentosa

ABSTRACT

The genetics of non syndromic retinitis pigmentosa [RP] is complex with numerous gene mutations. An attempt to overcome each individual mutation provides an overwhelming challenge. However targeting apoptosis which represents a final common pathway to photoreceptor cell death may provide a more practical approach. This study focused on some predictors of apoptosis in RP and their potential usefulness for patients' management and relatives' early diagnosis. Forty nine RP patients with thirty controls were evaluated genetically and ophthalmologicaly with assessment of plasma total nitrite and nitrate [as an index for nitric oxide], Plasma sFas as an index of apoptosis and plasma fatty acids levels. Autosomal recessive RP was the most common type of inheritance and the levels of plasma sFas and nitric oxide [NO] were significantly higher in retinitis pigmentosa compared to controls. Retinitis pigmentosa patients had significantly lower percentage of plasma omega3 fatty acids especially docosahexaenoic acid [DHA] relative to controls. sFas, NO, and DHA could differentiate between RP patients and control subjects with 100%, 100%, 97% sensitivity and 90%, 90%, 100% specificity respectively. sFas and nitric oxide levels were higher in cases of autosomal recessive [AR] type followed by X-linked, autosomal dominant, then simplex cases relative to the control group this may explain why AR and X-Linked forms are clinically more severe. In conclusion; diagnosis and treatment of RP could be aided by systemic markers or predictors of retinal degeneration. The consistent decrease in the plasma omega 3 fatty acids especially DHA, and increase sFas and nitric oxide levels may draw the attention upon the use of these markers as laboratory tests for relatives of affected patients who are at high risk for having retinitis pigmentosa. Also, omega 3 fatty acids in the form of DHA were recommended as possible supplements for the patients and their relatives