Purpose
Study of human lacrimal cell biology is limited by poor access to tissue samples, small tissue samples, heterogeneous cell composition of tissue samples and a lack of available cell lines. In order to develop lacrimal epithelial cell lines and further our understanding of lacrimal cell biology, we sought to find a better marker for lacrimal epithelial cells, compared to what is found in the literature. Previously, we demonstrated that Histatin-1 was highly and relatively specifically expressed in accessory lacrimal gland (ALG), using laser capture microdissection of ALG from muller’s muscle conjunctival resection specimens (MMCR), and Affymetrix ® microarray analysis.
Methods
We utilized human MMCR specimens and cadaveric main lacrimal gland (MLG) as sources of lacrimal tissue. These specimens were analyzed using immunofluorescence antibodies for Histatin-1, Lactoferrin and Aquaporin-5. Cells from MMCR and MLG were fixed, permeabilized and incubated with primary antibodies overnight then with secondary antibodies. Cells were then stained with mounting medium and analyzed using confocal microscopy.
Results
We found that Histatin-1 is more specific for lacrimal epithelium in MLG and MMCR compared to the relatively less specific Aquaporin-5 as we have previously shown. Lactoferrin is present in conjunctiva and lacrimal epithelium equally.
Conclusions
Histatin-1 is a good, and relatively specific marker for human lacrimal epithelium in ALG and MLG and can be used to identify lacrimal cells in future studies.