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S. Putano, S. Cavarretta, S. Lupo, L. Carlomusto, E. Perrotta, L. Petramala, D. Cotesta, C. Letizia, E.M. Vingolo; Angiotensin Plasma Levels and Retinitis Pigmentosa Patients . Invest. Ophthalmol. Vis. Sci. 2005;46(13):530.
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Purpose: To evaluate the relationship between angiotensin plasma levels and cellular damage in patients affected by Retinitis Pigmentosa (RP). Methods: Two groups of 18 subjects were selected for this study. The first group, aging from 27 to 55 y.rs., was selected among patient affected by Retinitis Pigmentosa (RP). excluding subjects with heart disease, hypertension, diabetes mellitus, liver troubles, lung disease and other ocular affections. The second group was selected as case–control. We performed a complete ophthalmological examination including: BCVA indirect ophthalmoscopy evaluating degree of RPE atrophy and severity pigmentation , visual field, ERG. The study group included 11 patients with typical RP and 7 patients with syndromic RP(2 patients with Cone–Roddystrophy, 5 Usher’s Syndrome). Patients were sampled from cubitail vein of 20 cc of blood in EDTA vacutainer. Angiotensin I (AGT I) and Angiotensin II (AGT II) levels were recorded. Results: RP patient presented AGT1 17±8,1 pg/ml and AGT2 15,33±6,5 pg/ml plasma concentration, while case–control subjects showed AGT1 6,2±1,7pg\ml and AGT2 7,5±1,96 pg\ml plasma concentration. Differences between two groups were evaluated with Student’s "T" test that demonstrated a high statistically significance for AGT1 (p=0,0342), for AGT2 (p=0,0001). Although the lack of data for some categories, we noted a very interesting increase of the average plasmatic level of AGT1 and AGT2 in all the categories: 5 US patients (AGT1 12.09 and AGT2 12.38), 11 RP patients (AGT1 17.31 and AGT2 10.93) and 2 CR patients (AGT1 22.40 and AGT2 25.9). Conclusions: RP is an inherited retinal disorder clinically characterized by a pale, waxy optic nerve head, bone spicule pigment and attenuated retinal blood vessels. Literature data underline a double function of angiotensin in retinal vessels: as vasoconstrictor and as indirect growth factor stimulating the production of VEGF and endothelin–1. Retinal vasoconstriction leads to a hypoxiemic condition that, probably induces a degeneration of retinal pigmented epithelium. Hence on the basis of our results, we can suppose an important pathogenetic role of angiotensin both in the reduction of retinal blood flow, and in the possible destructuration of vascular endothelium. Further studies would be usefull to investigate this hypothesis.
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