Transplantation of mesenchymal stem cells for lacrimal gland regeneration in a dry eye mouse model

Abstract

Purpose : Regeneration of lacrimal gland (LG) tissue in situ seems to be a promising approach to curatively treat dry eye disease (DED). Mesenchymal stem cells (MSC) exhibit therapeutic effects in a variety of pathologic conditions. Therefore, this study aims to investigate the therapeutic effect of MSC transplantation into damaged LGs of mice with experimentally induced DED.

Methods : LG-MSC were isolated from male eGFP expressing mice (B6-eGFP) and characterized according to the defined criteria. To induce DED, duct ligation (DL) of the right LG was performed on female C57BL/6J mice (8-10 weeks). Re-opening of the duct and MSC transplantation (2.5x10^5 MSC/2µl saline) were performed after 3 days (d). Tear secretion, Fluorescein staining of the ocular surface and LG weight were measured 5 min, 5d and 21d after transplantation (n=12/time). Number of transplanted MSC was calculated on the basis of male DNA in female LGs by qPCR (n=6/time). In addition, samples were collected for (immuno)-histology and expression analysis (qPCR) to evaluate acinar structures, apoptosis, inflammation and MSC distribution (n=6/time). Saline injected mice were used as controls (n=6/time).

Results : eGFP-MSC isolated from LG showed the characteristic phenotype. Tear secretion was significantly reduced due to DL, from 5.0±2.4 to 0.9±0.3 mm, but recovered to 5.2±2.3 and 5.5±3.3 mm 21d after MSC or saline injection, respectively. Fluorescein staining was not affected. LG weight decreased significantly from 6.7±0.5 to 3.1±0.4 mg at d5 after re-opening of DL, but recovered in MSC transplanted LGs to 5.4±0.7 mg at d21. 5 min after transplantation 8x10⁴±4x10⁴ MSC were detected, which decreased to 8x10³±4x10³ MSC at d5 and to 5x10²±1.3x10³ MSC at d21. DL led to apoptosis of LG cells, as Caspase-3 staining increased significantly from 23.7±9.2 to 283.2±39.2 cells/mm². Vital acinar structures significantly decreased from 88.6±4.4 to 0.8±0.7% due to 3d of DL. 21d after re-opening, acinar structures increased to 62.3±5.9% in MSC transplanted LGs, which was significantly enhanced (p=0.0039) compared to saline injection (50.1±11.5%).

Conclusions : The results of the study show, that transplantation of MSC into injured LG significantly improved the regeneration of acinar structures in a DED mouse model. Thus, the application of MSC appears to be a promising therapeutic approach for LG regeneration in patients suffering from severe DED.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.