251 - Oxygen Desaturations Are Associated with Elevated Lipid Peroxidation Products in Premature Neonates

Intermittent hypoxemia (IH) events are common in premature neonates. Elevated IH are associated with adverse outcomes such as retinopathy of prematurity, intraventricular hemorrhage, bronchopulmonary dysplasia, neurodevelopmental impairment, and mortality.  IH induces oxidative stress in laboratory models and may be a mechanistic pathway in morbidities of prematurity. Urine lipid peroxidation products are the result of polyunsaturated fatty acid oxidation in the eye, brain, and various cell membranes.

Objective:

Explore associations between IH and urine lipid peroxidation products.

Design/Methods:

A cohort of premature neonates (< 31 weeks gestation) had urine samples collected at 7 ±3 days of age. Oxygen saturation (SpO2) was continuously archived during hospitalization. Time in hypoxemia (percent time with SpO2< 80%) and frequency of IH/day (SpO2< 80% for >10 seconds and < 5 minutes) were assessed during the 24-hour period preceding urine collection. Urine samples were processed by solid phase extraction and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry for total lipid peroxidation products (Isofurans, Neurofurans, and Di-homo-Isofurans) [doi: 10.1089/ars.2021.0168]. Adjusted multiple quantile regression (QR) was performed at the 25^th, 50^th, and 75^th quantile for each lipid peroxidation product outcome with the IH predictor and a priori co-variants.

Results:

Patient characteristics of the 154 subjects are reported in Table 1. After adjustments, positive associations between percent time hypoxic and Isofurans at the 25^th and 50^th quantiles, and Neurofurans at the 25^th quantile in QRs were detected (Table 2). For IH frequency, positive associations with Isofurans and Di-homo-Isofurans were detected at the 75^th quantile (Table 3). Maternal tobacco use during pregnancy was positively associated with Isofurans and Neurofurans at 25^th, 50^th and 75^th quantiles and Di-homo-Isofurans at 50^th and 75^th quantiles. Intubation status was positively associated with Isofurans at 50^th and 75^th quantiles. Chorioamnionitis was positively associated with Di-homo-Isofurans at 50^th and 75^th quantiles. Small for gestational age was positively associated with Isofurans and Di-homo-Isofurans at the 75^th quantile.

Conclusion(s): These new data suggests that specific markers of oxidative stress may increase in relation to early IH exposure. This exploratory analysis also identifies patient characteristics associated with elevated lipid peroxidation. Future studies are needed to better understand mechanisms and relationships to morbidities of prematurity.

Funding: NIH U01HL133643 and U01HL133708.