During ARVO’s 2018 meeting in Honolulu, Hawaii, this week, investigators will share a newly discovered biomarker for keratoconus (KCN) called prolactin-induced protein (PIP) that is reduced in those with the disease.

The researchers collected saliva, tear and serum samples from 111 patients with KCN and 30 healthy controls, and found PIP protein expression was significantly down-regulated in all KCN samples compared with healthy controls, regardless of participant gender. Further analysis also revealed salivary DHEA-S levels were up-regulated in both men and women with KCN, while estrone and estriol levels were significantly down-regulated in KCN patients. Both estrone and estriol levels showed a female-dependent elevation compared with men.

“Our study shows that reduction in estrogen-based hormones and increase in androgen-based hormones, in correlation with reduced PIP levels in the human KC, may significantly alter the corneal homeostasis and exacerbate the underlying KC-corneal thinning,” researchers said in their ARVO abstract. “Hormone-PIP interdependency highlights the potential of PIP" as a KC biomarker.

“These investigators theorize that the reduced levels of this newly discovered biomarker, in conjunction with a reduction in estrogen-based hormones and an increase in androgen-based hormones, may exacerbate corneal thinning and alter corneal homeostasis,” explains Joseph Shovlin, OD, of Scranton, PA. “Along with other biomarkers already identified or yet to determined, PIP may aid in the management of this thinning disorder. For example, aquaporin-5 deficiencies have been identified in keratoconus patients in previous studies.”

Sharif R, Bak-Nielsen S, Sejersen H, et al. Novel biomarker for diagnosis, prognosis, and targeted therapy of keratoconus. ARVO 2018. Abstract 742.