The Dry Eye Zone

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Abstract: Corneal nerve regeneration



LASIK dry eye patients, don't get too excited yet, it's only at the bunny-trial stage but I'll definitely be following this one closely as it appears very promising. And looky, we are even mentioned in the conclusions.

Emphases mine.

PEDF plus DHA Induces Neuroprotectin D1 Synthesis and Corneal Nerve Regeneration after Experimental Surgery.
Invest Ophthalmol Vis Sci. 2009 Sep 24. [Epub ahead of print]
Cortina M, He J, Li N, Bazan N, Bazan H.
Ophthalmology, LSU, Chicago, United States.

Purpose: Define whether pigment epithelial-derive growth factor (PEDF) together with docosahexaenoic acid (DHA) enhances synthesis of neuroprotectin D1 (NPD1) and regeneration of corneal nerves damaged post-surgery.

Methods: A corneal stromal dissection was performed in the left eye of adult New Zealand rabbits treated with DHA+PEDF, PEDF, or DHA for 6 weeks. In vivo confocal images of the corneas were obtained at 2, 4 and 8 weeks and nerve areas quantified. At 8 weeks post-treatment, corneas were stained with tubulin betaIII antibody, and epithelial nerve area, sub-basal and stromal nerve plexus were quantified. At 1 and 2 weeks post-treatment, lipids were extracted from corneas and synthesis of NPD1 was analyzed by mass spectrometry. Epithelial cell density was quantified by confocal microscopy 8 weeks post-surgery.

Results: In vivo confocal images at 2 and 4 weeks post-surgery showed a 2.5-fold increase in corneal nerve area in PEDF+DHA-treated animals, compared with control animals. Increased nerve surface area in epithelia, sub-epithelial and stroma was observed in rabbits treated for 8 weeks with PEDF+DHA. PEDF or DHA alone did not produce a significant increase. NPD1 synthesis peaked at 1 week and was four times higher in PEDF+DHA-treated group, compared with controls.

Conclusions: PEDF+DHA promotes regeneration of corneal nerves. Neurotrophin-mediated NPD1 synthesis is suggested to precede nerve regeneration by demonstration of its accumulation upon addition of DHA and PEDF at earlier time points. Therefore, this signaling mechanism upregulates cornea nerve regeneration and may be targeted in neurotrophic keratitis, dry eye after refractive surgery, and other corneal diseases.