The relationship of endocan and plasma amino acid levels with retinopathy of prematurity

Retinopathy of prematurity (ROP) is a multifactorial vasculopathy that may lead to severe visual impairment in preterm infants. Endothelial dysfunction, inflammation, and oxidative stress are considered central mechanisms in its pathogenesis. However, the potential contribution of biochemical markers such as endocan—an indicator of endothelial activation— and alterations in amino acid metabolism has not been fully elucidated. This prospective observational study aimed to evaluate serum endocan levels and plasma amino acid profiles in preterm infants with ROP and to investigate their possible roles in the pathogenesis of the disease. A total of 38 preterm infants diagnosed with ROP and 40 gestational age–matched healthy preterm infants were included in the study. Detailed demographic and clinical data, neonatal intensive care unit (NICU) parameters, and biochemical measurements were recorded. Serum endocan levels were analyzed using enzyme-linked immunosorbent assay (ELISA), and plasma amino acid levels were assessed via high-performance liquid chromatography (HPLC). Our results demonstrated that infants in the ROP group had significantly longer NICU stay, increased need for oxygen therapy, and prolonged mechanical ventilation compared with the control group (p<0.001 for all). Serum endocan levels were markedly higher in the ROP group (163.78±39.22 vs. 92.61±23.24; p<0.001), supporting the involvement of endothelial activation and vascular inflammation in ROP development. Amino acid analysis revealed significantly lower levels of taurine and cysteine, and significantly higher levels of alloisoleucine in infants with ROP (all p<0.05). These alterations may reflect metabolic responses associated with oxidative stress and impaired cellular homeostasis, both of which are known to contribute to ROP pathophysiology. In conclusion, our study demonstrates that elevated serum endocan levels and distinct alterations in amino acid metabolism are associated with the development of ROP in preterm infants. These biomarkers may have potential value for early risk stratification, disease severity assessment, or adjunctive monitoring in ROP. Further large-scale prospective studies are needed to validate their diagnostic and clinical utility