Abstract
Purpose: :
To investigate if PEDF as secretory protein and component of human corrneal epithelium does occur in tear fluid of human healthy individuals in measurable concentrations.
Methods: :
Tear fluid samples prior and after stimulation were collected with blunted capillaries as reported before from 20 healthy individuals from both eyes. Due to the very little volume of individual samples collected prior to stimulation even pooled samples of unstimualted tears were created and analyzed. An ELISA assay, specific for PEDF was used for the analysis. Samples were analysed in duplicate whenever possible. As control served human recombinant PEDF.
Results: :
All samples turned out to be negative within the detection range. Even the pooled samples collected prior to induction of reflex tearing did not reveal the presence of any significant amount of PEDF.
Conclusions: :
The presence of PEDF in superficial layers of ocular surface tissues such as conjunctiva and cornea does most likely reflect a local production of PEDF in these tissues. The hypothesis that the PEDF localized in these tissues could derive from tear fluid can, according to our preliminary results, not be supported.
Keywords: cornea: tears/tear film/dry eye • lacrimal gland • cytokines/chemokines