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Date of Award
Bachelor of Science (BS)
Department of Integrated Science and Technology
Robert L. McKown
Keratoconjunctivitis sicca (KCS), also known as dry-eye disease, causes a deficiency of tears in both humans and canines. Due to the lack of effective therapeutics for the treatment of dry-eye disease, there is a market potential for a novel secretion enhancing factor. Lacritin, a naturally occurring tear glycoprotein, increases basal tearing in rabbits when topically applied to the ocular surface and shows potential as a dry-eye therapeutic. This study aims to characterize Lacritin as a biomarker of dry-eye disease in canines with KCS. A total of 46 canine tear samples, 24 normal and 22 diagnosed with KCS, were obtained through a collaboration with the Virginia-Maryland College of Veterinarian Medicine and transported to James Madison University (JMU) for analysis. A bicinchoninic acid assay (BCA) was used to determine total tear protein in the samples. An indirect enzyme-linked immunosorbent assay (ELISA) was then used to determine the total tear Lacritin concentration in each sample using previously cloned and purified canine Lacritin as a standard. Total tear protein of the samples was normalized and the proteins were separated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Western blot analysis with canine Lacritin antibodies was used to visualize Lacritin proteins and densitometry was used to determine the amount of the active Lacritin monomer (~18 kDa) band present. This study demonstrated that dry-eye samples had a significantly higher total protein concentration than normal samples, but a significantly lower relative intensity of the monomeric Lacritin band than normal samples. There was no significant difference in total Lacritin concentration between dry-eye and normal canines, as determined by the ELISA. Thus, the lower relative intensity of monomeric Lacritin present in canines with dry-eye suggests that monomeric Lacritin has potential as a biomarker of KCS, and should researched further in the future.
Gaylord, Eliza A., "Topical administration of lacritin peptide for the treatment of canine Keratoconjunctivitis sicca" (2017). Senior Honors Projects, 2010-current. 317.