Abstract
Purpose :
We previously have showed that intracamerally injected trabecular meshwork stem cells (TMSC) can reduce the intraocular pressure (IOP) and rescue the retinal ganglion cells in a transgenic mutant MyocY437H (Tg-MyocY437H) glaucoma mouse model (Xiong et al. eLife 2021). The purpose of this study was to discover a stem cell-free therapy using TMSC-derived trophic factors and explore the mechanisms of TM regeneration by stem cell trophic factors.
Methods :
TMSC secretome was collected and concentrated after culturing in serum-free and growth factor-free basal medium for 48 hrs. Four-month-old Tg-MyocY437H mice were periocularly injected with 20-ml human TMSC secretome weekly. Sham injection, untreated Tg-MyocY437H mice, and WT mice served as controls. IOP was measured weekly. TM cellularity and TM extracellular matrix component changes were examined by staining. Myoc expression in the TM tissue and secreted in the aqueous humor was detected by Western Blotting. The retinal ganglion cell (RGC) protection effect was evaluated by Optical Coherence Tomography (OCT) for the RNFL thickness and by retinal wholemount staining. Activated endogenous stem cells were identified by immunofluorescent staining on OCT4, ABCB5, and ki67. Statistical differences were analyzed by one-way ANOVA followed by Tukey multiple comparisons test using GraphPad Prism 9. P<0.05 was considered statistically significant.
Results :
Tg-MyocY437H mouse IOP was reduced after TMSC secretome injection and TM cellularity was increased. TM extracellular matrix component fibronectin was reduced after secretome treatment. Myoc in the TM tissue was reduced and secreted Myoc in the aqueous humor was increased after TMSC secretome treatment. RGC were significantly protected with increased RNFL thickness and RGC counts, similar to age-matched WT controls. Endogenous TMSC were activated after TMSC treatment with increased ki67 staining and increased OCT4 and ABCB5 staining.
Conclusions :
This study suggests that concentrated TMSC-secreted trophic factors (secretome) can reduce mouse IOP, promote TM regeneration, and prevent RGC damage. This could be partially related to endogenous TMSC activation.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.