Purchase this article with an account.
Nicholas W. DeKorver, Thomas V. Johnson, Natalie D. Bull, Keith R. Martin, Stanislav I. Tomarev; Elucidating Mechanisms of Retinal Ganglion Cell Neuroprotection by Mesenchymal Stem Cell Transplantation. Invest. Ophthalmol. Vis. Sci. 2011;52(14):2603.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Previously we reported that mesenchymal stem cells (MSCs) co-cultured with retinal explants protect against retinal ganglion cell (RGC) death. Here we investigate the mechanisms of this neuroprotection.
MSCs or fibroblasts were transplanted onto adult rat organotypic retinal explants and co-cultured for 7 days. Serum-free media was conditioned by 3 day cell culture incubation and concentrated roughly 40-fold. Retinal explants were treated twice daily with concentrated conditioned media (CCM). RGC survival was assessed as linear density of Islet-1+ and NeuN+ cells in the RGC layer. Concentrations of various factors in CCM were measured using multiplexed xMAP assays and ELISA.
Human MSC (hMSC) transplantation increased RGC survival (p<0.01 for all comparisons) compared to saline control (39.2±1.7 vs 21.4±0.8 Islet-1+ cells/mm; 42.0±2.1 vs 33.3±0.9 NeuN+ cells/mm) or human fibroblast transplantation (26.2±0.9 and 31.6±1.7 cells/mm, respectively). Similar effects were observed comparing rat MSCs to saline or murine fibroblasts. Treatment with rat MSC CCM increased RGC survival compared to controls (21.9±0.3 vs 13.8±0.6 Islet-1+ cells/mm; 79.6±1.9 vs 66.9±3.1 NeuN+ cells/mm; p<0.01 for both comparisons). Application of hMSC CCM did not improve RGC survival compared to saline, however treatment with fibroblast CCM significantly (p<0.05) reduced RGC survival (33.7±4.1 vs 44.8± 2.3 or 41.2±1.5 NeuN+ cells/mm) compared to hMSC CCM or saline, respectively. Among 27 factors analyzed, hMSCs secreted IL-2, IL-6, IL-13, IFN-γ, LIF, BDNF, NGF, PDGF-AA, TSP-1, and melatonin at levels 5-500 fold higher than fibroblasts. In contrast, human fibroblasts secreted EGF and bFGF at ≥50 fold higher levels than hMSCs.
Transplantation of MSCs evokes robust RGC neuroprotection that may be mediated by secreted factors. Reduced efficacy of hMSC CCM could be due to inadequate concentrations of survival promoting factors relative to inhibitors, or could suggest that cellular contact is important for neuroprotection. Continuing work aims to improve treatment protocols to maximize RGC neuroprotection and to determine the effects of MSC-specific secreted factors on RGCs.
This PDF is available to Subscribers Only