Maternal dietary deuterated docosahexaenoic acid protects against hyperoxia induced retinal vascular arrest

Abstract

Purpose : Advances in neonatal care have led to viability at lower gestational ages, but hyperoxia remains a critical driver of redox imbalance in developing organs e.g. the retina, increasing risk of retinopathy of prematurity (ROP). Pro-resolving mediators derived from docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)can attenuate ROP, but are highly susceptible to lipid peroxidation. Isotope-reinforced deuterium labeled DHA (D-DHA) protects against retinal pathologies in adult mice. We hypothesize that dietary D-DHA supplementation in mouse dams will protect offspring against retinal vascular arrest (VA) by modulation of redox homeostasis in oxygen-induced retinopathy (OIR).

Methods : C57BL/6J female mice were divided into room air control (RA) and hyperoxia groups. They were then fed diet with either a) no DHA, b) control H-DHA, or c) D-DHA for seven days prior to conception continuing through delivery of offspring and maternal feeding of breastmilk. Enrichment of D-DHA in breast milk was confirmed in P0 mouse pups in gastric milk pellets and retinal tissue at P7 by GC-MS. Mouse pups were then exposed to 75% hyperoxia from P7-P12, followed by room air from P12-P17. Retinal flat mounts were analyzed for VA (P12) and NV (P17). Retina and serum were collected at P17 for fatty acid analysis by GC-MS and lipid peroxidation by thiobarbituric acid assay (TBA). HO-1, SOD-2, and VEGF protirn were analyzed by western blots.

Results : Dietary D-DHA passed through breastmilk to offspring incorporating into retinal tissue at P7 (88%, p-value<0.0001). D-DHA pups had less retinal VA at P12 (12.7%) vs no DHA (15.1%) p =0.0021 after hyperoxia. At P17 there was no improvement in NV, but D-DHA increased total DHA in serum (p=0.0067) and retina (p=0.0182). D-DHA retinas also had lower TBA and HO-1 expression. Differences in SOD-2 and VEGF were not significant.

Conclusions : Maternal dietary D-DHA protects against hyperoxia-induced retinal VA. Preservation of early normal vascular development is critical in preventing ROP. D-DHA also increased total DHA levels in serum and retina at P17, and attenuated redox markers. Despite protecting early vessel growth and redox homeostasis, it is unclear why D-DHA did not reduce NV. We are now analyzing retinal gene expression of vascular, oxidative, and immune markers at P12, P17, and 3 mo age. Protective effect on visual acuity is being assessed by ERG.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.