Analysis of Salivary Cytokines in Retinopathy of Prematurity

Abstract

Background/objectives: This cohort study aimed to establish a correlation between salivary cytokines and retinopathy of prematurity (ROP) in premature neonates. Additionally, we sought to identify a minimally invasive method for cytokine detection in this population.

Methods: We recruited premature neonates born at less than 34 weeks gestational age (GA), with no history of maternal or neonatal infections. Salivary samples were collected on their first (D1) and seventh (D7) days of life, and cytokine levels were measured using the MILLPLEXMAP Human multiplex assay.

Results: A total of 125 neonates were included in the study, categorized into two groups based on the severity of ROP: None to Mild and Moderate to Severe. The salivary levels of interleukin (IL)-6, IL-8, vascular endothelial growth factor (VEGF), and tumor necrosis factor (TNF)-α on D1 and D7 were significantly higher in the Moderate to Severe ROP group compared to the None to Mild ROP group (p = 0.005, 0.004, 0.026, 0.018, 0.001, 0.007, 0.025, and 0.002, respectively). After adjusting for GA, the levels of IL-6 and VEGF on D7 were significantly elevated in the Moderate to Severe ROP group compared to the None to Mild ROP group (p = 0.024 and 0.016, respectively).

Conclusions: This study establishes a novel, non-invasive method for the early prediction of ROP in premature neonates by correlating salivary cytokine levels in early life with the subsequent development of ROP.

Keywords: cytokines; retinopathy of prematurity; saliva.

Figure 1

Patient enrollment. A total of 186 neonates born at or less than 34 weeks’ GA were recruited. Of these, 43 were excluded due to infections, and 18 neonates died before discharge. Ultimately, 125 surviving neonates were enrolled and categorized into two groups based on the severity of their ROP.

Figure 2

Salivary cytokine levels in neonates with varying ROP severity. The blue boxplots represent cytokine concentrations in the two groups on D1 (A,C,E,G), while the purple boxplots represent concentrations on D7 (B,D,F,H). The horizontal black lines within the boxes indicate the median cytokine levels. Asterisks denote significant differences between the two groups (* p < 0.05).

Figure 3

Correlations between GA and VEGF Levels. Distribution plots illustrate salivary VEGF levels on D1 (A) and D7 (B) among neonates with varying GAs. Solid lines depict the correlations, along with the corresponding p values and r² values.