Unravelling Novel Roles of Salivary Exosomes in the Regulation of Human Corneal Stromal Cell Migration and Wound Healing

Salivary exosomes have demonstrated vast therapeutic and diagnostic potential in numerous diseases. This study pioneers previously unexplored roles of SE in the context of corneal wound healing by utilizing primary corneal stromal cells from healthy (HCFs), type I diabetes mellitus (T1DMs), type II DM (T2DMs), and keratoconus (HKCs) subjects. Purified, healthy human SEs carrying tetraspanins CD9+, CD63+, and CD81+ were utilized. Scratch and cell migration assays were performed after 0, 6, 12, 24, and 48 h following SE stimulation (5 and 25 mu g/mL). Significantly slower wound closure was observed at 6 and 12 h in HCFs with 5 mu g/mL SE and T1DMs with 5 and 25 mu g/mL SE. All wounds were closed by 24-hour, post-wounding. HKCs, T1DMs, and T2DMs with 25 mu g/mL SE exhibited a significant upregulation of cleaved vimentin compared to controls. Throm-bospondin 1 was significantly upregulated in HCFs, HKCs, and T2DMs with 25 mu g/mL SE. Lastly, HKCs, T1DMs, and T2DMs exhibited a significant downregulation of fibronectin with 25 mu g/mL SE. Whether SEs can be utilized to clinical settings in restoring corneal defects is unknown. This is the first-ever study exploring the role of SEs in corneal wound healing. While the sample size was small, results are highly novel and provide a strong foundation for future studies.

Automated summary

This study explores the role of salivary exosomes in corneal wound healing for the first time. The results show that stimulation with salivary exosomes can slow down wound closure in healthy individuals and diabetic patients, and it affects the expression of certain proteins. However, it is still unclear whether salivary exosomes can be used in clinical settings to restore corneal defects.