Anti-angiogenic found in tears

Pigment-epithelium-derived factor (PEDF), which is known for its importance in the prevention of neovascularization of the retina, can be found in measurable amounts in the human tear fluid of healthy subjects. It may therefore be important in the regulation of corneal vascularization, according to a report published online ahead of print by Ophthalmic Research.

Oran Abdiu, MD and co-workers from St Erik's Eye Hospital, Karolinska Institutet, Stockholm, Sweden collected tear fluid samples from 18 healthy individuals and analysed them using a commercial ELISA. Samples were also collected from five patients with pterygium and, as a positive control, two samples were taken from the subretinal fluid of patients following retinal detachment surgery.

The researchers found that PEDF concentrations were below the detection limit (i.e. <0.1 ng/ml) in the majority of samples from healthy subjects. However, PEDF was discovered in three of the samples with significant concentrations of 2, 32 and 53 ng/ml. There were no detectable concentrations among the group with pterygium.

The researchers were therefore able to confirm that PEDF can be found in measurable amounts in human tear fluid of healthy individuals and it may play a role in the effects and regulation of vascularization at the ocular surface.