Abstract
Purpose :
As a measure of inflammation, inflammatory markers are less influenced by media opacity when compared to laser flare photometry and are more objective and sensitive but also more invasive than standard of care slit lamp cells and flare. This study evaluated the correlation of inflammatory markers in the aqueous humor and tear film using a rabbit model during sham cataract surgeries.
Methods :
Aqueous and tear samples were collected from the left eye of 9 female New Zealand white ~1 year old rabbits. Eight eyes received a sham phacoemulsification procedure, and 1 eye had uveitis induced with a Lipopolysaccharide anterior chamber injection to serve as positive control. The aqueous and tear samples were collected using a 25-gauge cannula and a glass syringe. A balanced salt solution sample served as negative control. Tumor Necrosis Factor Alpha (TNF-α), Interleukin-8 (IL-8), Interluekin-6 (IL-6) and Monocyte Chemoattractant Protein-1 (MCP-1) were selected as they are known to cause ocular tissue damage and be elevated after cataract surgery. Using Luminex Multiplex Assay, the concentration of the 4 markers was recorded in milligrams/deciliter (mg/dL). Regression analysis using Microsoft Excel provided the coefficient of determination (R2) for each marker or combination of markers in aqueous and tears.
Results :
The concentration of inflammatory markers was highest in the test and positive control samples and lowest in the negative control sample. Where the concentration was below the limit of detection, a conservative value of 0 mg/dL was assigned. The mean concentration in mg/dL of TNF-α was 115.15 and 106.17, IL-8 was 122.30 and 230.34, IL-6 was 35.43 and 48.08, MCP-1 was 33.76 and 26.14 in aqueous and tears, respectively. The best-fit curve that determined the relationship between the aqueous and tear marker concentration was a second-degree trinomial. An R2 of approximately 0.7 or greater was noted for IL-8 in aqueous and TNF-α in tears, IL-6 in both aqueous and tears as well as IL-6 in aqueous and MCP-1 in tears with R2 = 0.65, 0.78 and 0.95, respectively.
Conclusions :
It may be possible to use tear inflammatory marker concentration to evaluate intraocular inflammation. Further investigation is needed to confirm these findings as they have the potential to allow ophthalmic physicians to better manage uveitis as well as titrate postoperative treatment to match the patient’s specific inflammatory response.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.