Suprachoroidal Spheroidal Mesenchymal Stem Cell Implantation in Retinitis Pigmentosa: Clinical Results of 6 Months Follow-up

A prospective clinical trial was conducted in patients with RP at the department of ophthalmology, Acibadem University, Medical school. The study was approved by the Review Board of Cell, Organ and Tissue Transplantation Department of Turkish Ministry of Health. The study was performed in accordance with the Declaration of Helsinki.

Patient Evaluation Fifteen patients with clinical and genetic diagnoses of RP were included in the study. Patients underwent ophthalmic examination including best corrected visual acuity (BCVA), intraocular pressure, anterior segment examination and dilated fundus examination (with topical tropicamide %1 and phenylephrine 2.5%). Each eye underwent spectral domain OCT scanning with Cirrus 5000 HD-OCT Angioplex (Carl Zeiss Meditec, Dublin, CA, USA), fundus autofluorescence and fundus fluorescein angiography (Heidelberg Engineering, Germany). MD (mean deviation) and PSD (pattern standard deviation) parameters of 10-2 and 30-2 visual field (VF) testing strategies with a Humphrey Field Analyzer model 750I (Carl Zeiss Meditec, Dublin, CA, USA) were obtained. The electrophysiological function was assessed with mfERG evaluation (Monpack 3, Metrovision, France) according to the International Society for Clinical Electrophysiology of Vision (ISCEV) guidelines [27]. BCVA was converted to the logarithm of the minimal angle of resolution (logMAR) equivalent.

The patients were excluded from the study, if they had 1) coexisting ocular pathology that may affect visual acuity, visual field and retinal morphology such as glaucoma, uveitis, previous vitreoretinal surgery, 2) coexisting cataract that may affect mfERG, visual field and/or ocular imaging, 3) refractive error that may affect measurements higher than +6.00D, lower than -6.00D 4) coexisting systemic diseases that may affect visual function such as diabetes, vasculitis, rheumatological diseases and chronic immunosuppressive use, 5) periocular injection of platelet-rich blood and transcorneal electrical stimulation in previous 6 months and 6) previous ocular surgery.

Electrophysiologic Testing After 30 minutes of dark adaptation and pupil dilatation with the application of one drop of tropicamide 1% (Tropamid, Bilim ˙Ilaç, Turkey), phenylephrine 2.5% (Mydfrin, Alcon), and proparacaine hydrochloride 0.5% (Alcaine, Alcon), ERG jet electrodes were placed. Multifocal electroretinographies were recorded after pupil dilatation. The stimulated retinal area was subtended in an area of 60° x 55°; 61 hexagon stimulants were used with alternating black (5 cd/m2) and white (100 cd/m2) stimulants. The concentric rings were analyzed according to International Society for Clinical Electrophysiology of Vision standards.13 The amplitude and latencies of P1, N1, and N2 components were recorded for every ring. The mean signal amplitudes (MSAs) of multifocal electroretinography (mfERG) in the macula (central 0°-2°) and the peripheral (2°-5°,5°-10°, 10°-15°, and >15°) signal amplitude changes were evaluated separately.

Spheroidal Stem Cell Preparation First passage umbilical cord-derived mesenchymal stem cell was obtained from Labcell Cellular Laboratory Center which provides GMP (good manufacturing practices) conditions.