P2C245: Erythrocyte Polyunsaturated Fatty Acid Content and Chronic Lung Disease

Background: Chronic lung disease (CLD), a common complication of prematurity, is associated with decreased lung function, pulmonary hypertension, and poor neurodevelopment. While the pathogenesis of CLD is multifactorial, inflammation plays a major role in CLD. Polyunsaturated fatty acids (PUFAs) are precursors to eicosanoids that regulate inflammation and angiogenesis. Although multiple studies have evaluated the role of PUFAs in the prevention of CLD, results are conflicting. This single-site, prospective, observational study aimed to investigate the association of CLD severity and PUFA percentage (%) in the red blood cell membrane (RBCM).

Methods: Inclusion criteria included: < 32 weeks gestational age (GA), < 1.5 kg birth weight, and at least one PUFA RBCM measurement in the first month of life. CLD was defined as the need for supplemental oxygen at 36 weeks corrected GA. Subjects were also grouped by CLD severity [no CLD (no respiratory support), Grade 1 CLD ( < 2L nasal cannula), Grade 2 CLD (>/= 2L nasal cannula or non-invasive positive pressure), and Grade 3 CLD (invasive mechanical ventilation)]. RBCM PUFAs were measured using gas chromatography-mass spectrometry. Generalized estimating models were used to test for group differences over time. Pairwise means with comparisons between groups were extracted from the models.

Results: Compared to the no-CLD cohort (n=29), the CLD cohort (all grades, n=41) were more premature, required more days of intubation, and were more likely to receive a RBC transfusion in the first month of life (p < 0.001 for all) (Table 1). Similar results were observed when comparing groups by CLD severity. Despite an increase in the RBCM % of the essential fatty acid linoleic acid, its metabolite arachidonic acid was significantly lower in the CLD cohort compared to the no-CLD cohort over time (p=0.004). Similar results were noted when investigating CLD by severity. When compared to the no-CLD cohort, the Grade 2 and Grade 3 CLD cohorts had a higher linoleic acid % in their RBCM but less arachidonic acid over time (p < 0.05 for all). While there was a significant increase over time in the RBCM % of α-linolenic acid in the CLD cohorts compared to no-CLD cohort, its downstream PUFA, docosahexaenoic acid, was unchanged (Table 2).

Conclusion: A greater RBCM % of linoleic acid, yet lower RBCM % of arachidonic acid was associated with CLD and CLD severity. Future studies elucidating how PUFAs and their downstream eicosanoids contribute CLD are warranted.