Purpose
Adult human bone marrow contains stem cells that play an important role in tissue repair and maintenance. A subpopulation of these stem cells, characterized as CD34+, has the ability to home into damaged tissue, including degenerating retina. This study explored the safety and feasibility of intravitreal injection of autologous CD34+ cells from bone marrow as a potential therapy for degenerative macular disease.
Methods
Patients with hereditary or dry age-related macular degeneration (AMD) with best corrected visual acuity (BCVA) of 20/100 to 20/400 in the worse eye were enrolled. Bone marrow aspiration from the iliac crest was performed under local anesthesia. The CD34+ cells were isolated from the aspirate under GMP- (Good Manufacturing Practice)-conditions using a magnetic cell-sorter and injected intravitreally. Patients were followed for 6 months with serial eye examination, ETDRS BCVA, microperimetry, fluorescein angiography, multifocal and full-filed electroretinography (ERG), spectral-domain OCT and adaptive optics-OCT imaging.
Results
Three eyes (three subjects) were enrolled (one with dry atrophic age-related macular degeneration (AMD); two with Stargardt’s disease). The bone marrow aspiration and intravitreal injection of cells were well-tolerated and without any adverse effects during the follow-up period. A total of 3 to 7 million CD34+ cells were isolated and injected intravitreally per eye. BCVA improved 1.5 to 4 lines in the study eye during the follow-up period. No funduscopic or angiographic changes were noted during the follow-up except for some mild progression of geographic atrophy extrafoveally in both eyes of the AMD subject. Multifocal ERG showed a trend toward stabilization in the study eye compared to the contralateral eye. Full-field ERG showed stable or enhanced amplitude in the study eye. AO-OCT imaging showed new punctuate hyperreflectivity within the retinal layers suggestive of intraretinal incorporation of the stem cells in the eye with Stargardt’s disease.
Conclusions
In this initial exploratory study, intravitreal injection of autologous CD34+ stem cells from bone marrow appears feasible and well-tolerated in eyes with degenerative macular disease. A larger study with longer follow-up is planned to further explore this therapy.
Keywords: 466 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials •
721 stem cells •
696 retinal degenerations: hereditary