Role of Caspase-1 as a Biomarker of Ocular Surface Damage

Abstract

To examine the potential of caspase-1 as a biomarker for ocular surface damage. Cross-sectional study. A total of 113 tear samples (64 subjects) were analyzed. Sixty-one samples were from individuals with dry eye disease (DED), defined as Ocular Surface Disease Index (OSDI) ≥13 and/or corneal staining (CS) ≥3; 32 were from individuals who used glaucoma medication, irrespective of DED metrics; and 20 were from controls (CS <3 and OSDI <13). All individuals completed a medical history form and underwent an ocular surface assessment. Protein levels of caspase-1 were determined by enzyme-linked immunosorbent assay off Schirmer's strips. The primary analysis compared caspase-1 levels in individuals with signs of ocular surface damage (CS ≥3) in both case groups and controls. Secondary correlational analyses were conducted to examine relationships between caspase-1 levels and ocular signs and symptoms. Finally, area under the curve (AUC) analyses were performed to examine relationships between inflammatory markers and CS. The mean age of the population was 58±18 years; 70% were female. Tear samples from individuals with ocular surface damage presented higher caspase-1 levels than the control group. Caspase-1 levels showed a moderate positive correlation with CS (Spearman r=0.31; P=.001) and eye redness (Spearman r=0.39; P=.004), and a negative correlation with Schirmer's (Spearman r=-0.46; P < .001) and tear break-up time (Spearman r=-0.33; P=.0006). Caspase-1 showed higher sensitivity and AUC for detecting ocular surface damage than InflammaDry, and its expression was not affected by anti-inflammatory agents. Caspase-1 levels were higher in the tears of individuals with ocular surface damage, suggesting its potential to be used as a biomarker and/or therapeutic target.