Histatin-1 is present in normal human tears and reduced in aqueous deficient dry eye disease

Abstract

Purpose : Histatin peptides are critical elements of the salivary anti-microbial and wound healing apparatus. Histatin-1 was recently found to improve corneal epithelial wound healing and be present in the lacrimal apparatus. We sought to determine whether histatin-1 (H1) is present in normal human tears. In addition, we sought to determine whether tear levels of H1 varied between normal patients and those with aqueous deficiency dry eye disease (ADDE).

Methods : Patient data and clinical samples were obtained from 9 normal patients (18 eyes) and 8 ADDE patients (16 eyes). Relevant patient characteristics, including age, sex, and dry eye disease (DED) diagnostic parameters were also collected. Multiple protein detection methods, including immuno-dot-blotting (IDB), Western immunoblotting (WB) and Multiple Reaction Monitoring (MRM), were used to detect H1 in samples,. Enzyme linked immunosorbent assay (ELISA) was used to compare concentrations of H1 between groups. Standard statistical methods were used to compare H1 levels and other parameters between groups, and diagnostic performance was tested using the receiver operating characteristic (ROC).

Results : H1 was detected in normal tears, using IDB, WB and MRM methods. ADDE patients had significantly lower H1 concentrations (118.11±86.20 ng/ml) than the normal group (866.42±240.18 ng/ml) (p=0.005), while controlling for age and sex. ROC analysis indicated that H1 concentration is potentially a biomarker for ADDE (area under curve = 0.93). Reclassification of patients by DED parameters, Ocular Surface Disease Index (OSDI) (≤13, >13) and Schirmer I (<10mm, ≥10mm) showed significant differences in H1 level (OSDI, p=0.014) and marginal significance of Schirmer I (p = 0.078)

Conclusions : This is the first demonstartion that H1 is present in normal human tears. H1 concentrations are lower in ADDE patients and H1 may have diagnostic potential in evaluation of patients with ADDE.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

Fig. 1 Detection of H1 in Human Tears using Western blotting. Results demonstrate the presence of a band at the appropriate size for H1 detected by anti-H1 antibody in tears of a normal patient, saliva of two normal patients and Syn. H1.