Background: Retinopathy of prematurity (ROP) is a potentially blinding, retinal neovascular disease. Systemic prolactin accesses the retina to regulate blood vessels. Prolactin is proangiogenic and can be cleaved to antiangiogenic vasoinhibins. We investigated whether circulating prolactin and vasoinhibins associate with incidence and progression of ROP.
Methods: A prospective, longitudinal, case-control study covering postnatal weeks 1 to 9 measured serum prolactin, vasoinhibins, and vascular endothelial growth factor (VEGF) weekly in 90 premature infants diagnosed as ROP or control.
Results: Prolactin levels were higher in ROP than in control patients before (106.2 ± 11.3 (SEM) vs. 64.7 ± 4.9 ng/ml, postnatal week 1) and during (120.6 ± 10 vs. 84.7 ± 7.5ng/ml, postnatal week 5) ROP diagnosis. Prolactin, but not gestational age, birth weight, Apgar score, sepsis, or ventilation time, correlated with ROP. The relative risk (RR) of developing ROP increased if Prolactin (PRL) levels were higher than thresholds of 80 ng/ml (RR = 1.55, 95% CI: 1.06-2.28), 100 ng/ml (RR = 1.63, 95% CI: 1.14-2.34), or 120 ng/ml (RR = 1.95, 95% CI: 1.41-2.68). Vasoinhibin levels were 39.7% higher (95% CI: 4.5-77.5) in the circulation of ROP than in control patients at postnatal week 1 and similar thereafter, whereas VEGF serum levels were always similar.
Conclusion: High serum prolactin and vasoinhibin levels predict and may impact ROP progression.