Phospholipids studies in human corneal epithelial cells from Climatic Droplet Keratopathy patients

Abstract

Purpose : Climatic droplet keratopathy (CDK) is an acquired degenerative disease of the cornea of unknown etiology, characterized by progressive opalescence of cornea’s most anterior layers. CDK is highly prevalent in certain rural communities around the world living under harsh environmental conditions (low humidity, constant winds and lack of protection to chronic exposure of ultraviolet radiation). To increase our knowledge about CDK’s etiology, we performed a pilot study to evaluate phospholipids profile (phosphatidylcholine-PC- and phosphatidylserine-PS) in corneal epithelial cells from 3 CDK patients

Methods : Corneal epithelial cells from CDK areas (inter palpebral aperture) and from non affected areas (corneal epithelium covered by eye lids) were obtained from patients diagnosed with CDK who did not presented any other surface eye disease. After reading a summary of the project, a consent form was signed by the patients. All procedures were in accordance to a protocol approved by institutional review process and the tenets of the Declaration of Helsinki. Corneal cells were subjected to lipid extraction using a modified Bligh and Dyer method; protein concentrations were determined using the Bradford’s method. Lipids were identified and subjected to ratiometric quantification using TSQ Quantum Access Max triple quadrupole mass spectrometer, using appropriate class specific lipid standards

Results : We obtained lipid profiles for two classes of phospholipids: PC and PS. The phospholipid classes showed lower total amounts (pmol/µg protein) in affected areas compared to control areas from corneas of CDK patients: PC and PS control values were 5 times and 34 times higher than in CDK affected areas, respectively. Comparative profiles between CDK areas and control areas showed several common species between them. Unique lipids were also identified in the two classes of phospholipids, in control areas that were absent in CDK areas and vice versa

Conclusions : It was possible to quantify and identify phospholipids in control and CDK affected areas in corneal epithelial cells from patients with CDK. The fact that we found lower amount of lipids in CDK areas compared to control areas could be attributed to the lipid peroxidation that takes place as a consequence of oxidative stress. More studies need to be done to confirm and extend these results

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.