ET-1 plasma levels, choroidal thickness and multifocal electroretinogram in retinitis pigmentosa

AimTo assess the relationship between both photoreceptor function and choroidal thickness and endothelin-1 (ET-1) plasma levels in patients with early stage retinitis pigmentosa (RP).Main methodsWe compared 24 RP patients (14 males and 10 females), 25 to 42 years of age (mean age: 34 ± 7 years) with 24 healthy controls (12 males and 12 females) aged between 28 and 45 years (mean 36 ± 6.8 years). All patients underwent visual field test, electroretinogram and multifocal-electroretinogram and choroidal thickness measurement by using spectral domain optical coherence tomography.Key findingsRP patients had a visual acuity of 0.95, a mean defect of the visual field of − 7.90 ± 1.75 dB, a pattern standard deviation index of 6.09 ± 4.22 dB and a b-wave ERG amplitude of 45.08 ± 8.24 μV. Notably RP subjects showed significantly increased ET-1 plasma levels and reduced choroidal thickness compared with controls: respectively, 2.143 ± 0.258 pg/ml vs. 1.219 ± 0.236 pg/ml; p < 0.002 and 226.75 ± 76.37 μm vs. 303.9 ± 39.87 μm; p < 0.03. Spearman's correlation test highlighted that the increase of ET-1 plasma levels was related with the decrease of choroidal thickness (r = − 0.702; p < 0.023) and the increase of implicit time in both ring 2 (r = − 0.669; p < 0.034) and ring 3 (r = − 0.883; p < 0.007) of mfERG.SignificanceIncreased ET-1 plasma levels may play a key role in the impairment of retinal and choroidal blood flow due to the vasoconstriction induced by ET-1. This could lead to worsening of the abiotrophic process of the macular photoreceptors.

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