Human stem cells home to and repair laser-damaged trabecular meshwork in a mouse model

Abstract

Glaucoma is the leading cause of irreversible vision loss, and reducing elevated intraocular pressure is currently the only effective clinical treatment. The trabecular meshwork is the main resistance site for aqueous outflow that maintains intraocular pressure. In this study, we transplanted human trabecular meshwork stem cells (TMSCs) intracamerally into mice that received laser photocoagulation over a 180° arc of the trabecular meshwork. TMSCs preferentially homed and integrated to the laser-damaged trabecular meshwork region and expressed differentiated cell markers at 2 and 4 weeks. Laser-induced inflammatory and fibrotic responses were prevented by TMSC transplantation with simultaneous ultrastructure and function restoration. Cell affinity and migration assays and elevated expression of CXCR4 and SDF1 in laser-treated mouse trabecular meshwork suggest that the CXCR4/SDF1 chemokine axis plays an important role in TMSC homing. Our results suggest that TMSCs may be a viable candidate for trabecular meshwork refunctionalization as a novel treatment for glaucoma.

Adipose‐derived stem cells integrate into trabecular meshwork with glaucoma treatment potential

“…All experimental procedures were reviewed and approved by the University of Pittsburgh Institutional Animal Care and Use Committee and carried out according to guidelines of the Association for Research in Vision and Ophthalmology Resolution on the Use of Animals in Ophthalmic and Vision Research. Intracameral injection followed the procedures previously described, with transplanted cells being prelabeled with DiO 34,35 . About 10 000 cells (ADSC‐TM cells, primary ADSCs, fibroblasts, n = 25 in each group) in 2‐µL DMEM/F12 were injected.…”

“…Outflow facility measurement followed existing procedures 35,57 with minor modifications. The perfusion system consisted of a computer‐controlled syringe pump (Harvard Apparatus) that delivered a variable flow rate (Q) to the anterior chamber to maintain a desired IOP, as monitored by a pressure transducer (Honeywell) connected to a computer control system (Labview).…”

“…Primary TM cells; TM cells treated with SDF1α and SDF1β (Millipore) at 80 ng/mL each (TM‐SDF1αβ) to increase the TM cell expression of SDF1; or TM cells treated with SDF1 antibody (Millipore) at 1 µg/mL (TM‐SDF1Ab) for 72 hours to block the TM cell surface SDF1 expression were seeded at the bottom of 24‐well culture plates as chemoattractant. ADSCs, ADSC‐TM cells, or the cells treated with the CXCR4 antagonist II IT1t 35,63 at 44 nM for 72 hours were labeled with DiO and seeded in the cell culture inserts with 8‐µm pores. After 24‐hours incubation, the Transwell membranes of the culture inserts were fixed, stained with DAPI, and mounted.…”

“…After injection in the normal mouse anterior chamber, these stem cells can home to TM tissue and maintain IOP in the normal range 34 . After injection into the anterior chamber of mice with partially damaged TM tissue due to laser photocoagulation, TM stem cells can specifically home to laser‐damaged TM regions and repair the tissue 35 …”

“…It has been reported that chemokine stromal cell‐derived factor 1 (SDF1) and its receptor C‐X‐C chemokine receptor type 4 (CXCR4) play important roles in bone marrow hematopoietic stem cell homing 47 and in TM stem cell homing to the TM 35 . Here, we compared the specific integration of primary ADSC and ADSC‐TM cell grafts into mouse TM tissue and explored possible mechanisms of cell homing.…”