The presence of stem cells in the human lacrimal drainage system: A proof of principle study

PurposeTo investigate the presence of stem cells within the lacrimal drainage system.MethodsA prospective interventional case series where human lacrimal sac tissue biopsies were obtained from patients undergoing endoscopic dacryocystorhinostomy or a dacryocystectomy surgery at a tertiary care Dacryology Services. Histopathology, immunohistochemistry, and gene expression studies were performed to check the expression of several basic stem/progenitor specific genes - <i>Cd90, Cd105, Cd73</i>, <i>Abcb5, Abcg2,</i> and <i>P63α.</i>ResultsThe lacrimal sac showed positive expression of general stem cell markers (ABCB5, ABCG2, and P63<i>α)</i> and mesenchymal stem cell-specific markers <i>(CD73, CD90, CD105)</i> using transcriptional and immunolocalization studies<i>.</i> Interestingly, CD73 and CD105 double-positive cells and CD73 and CD90 double-positive cells (specific markers for mesenchymal stem cells) were noted in the lacrimal sac stroma and were confirmed not to be vascular endothelial cells.ConclusionThe present study is proof of the principle of the presence of a wide range of stem cell markers within the human lacrimal sac. This study could serve as a foundation for investigating the stem cells and characterizing them further to better understand the lacrimal drainage disorders.