Investigation of histatin-1, histatin-3, and histatin-5 peptide levels in corneal epithelial cells obtained from patients with keratoconus

Purpose The aim of this research was to investigate the contribution of histatin peptides in the pathophysiology of keratoconus. Methods This prospective study investigated the presence of histatin peptides in corneal epithelial samples taken from 66 adult patients with keratoconus (stage 1, n = 22; stage 2, n = 21; and stage 3, n = 23) and 20 postmortem controls. The histatin-1, −3, and −5 levels were measured using the ELISA method. Results Histatin-3 significantly increased in stage 1 (control, 274.05 ± 15.72 ng/mg total protein, vs. patients, 528.17 ± 47.45 ng/mg total protein, p < 0.001) and stage 2 (374.33 ± 15.05 ng/mg total protein, p < 0.05), but no changes for histatin-1 and −5 levels were observed. Histopathological analysis showed that corneal epithelial cell thickness increased in keratoconus, and this increase augmented proportionally with the stages. The histopathological scores were significantly elevated in stages 2 and 3. Interestingly, positive correlations were observed between histatin-1 and histatin-3 levels in all stages. Conclusion These preliminary data suggest that histatin-3 may be involved in the early stages of keratoconus. These findings are preliminary and should be confirmed in larger, prospective cohorts.