Impact of SMOFLipid on Pulmonary Alveolar Development in Newborn Guinea Pigs

Abstract

Background: Parenteral nutrition (PN) is associated with bronchopulmonary dysplasia in premature infants. In animals, PN leads to alveolar loss following stimulation of apoptosis by oxidative stress (oxidized redox potential). Peroxides and aldehydes generated in PN can induce hypo-alveolarization. The implication of peroxides, which is reduced by light protection, is demonstrated. The implication of aldehydes from omega-6 fatty acids oxidation is expected. The hypothesis is that composition and light exposure of PN influences bronchopulmonary dysplasia development. Since SMOFLipid (SMOF) contains a lower amount of omega-6 fatty acids than Intralipid (IL), the aim was to compare, the impacts of PN compounded with SMOF or IL, photo-protected or not, on alveolar development.

Materials and methods: Three-day-old Guinea pigs received PN, photo-protected or not, made with SMOF or IL through a jugular vein catheter. After 4 days, lungs were sampled for determinations of redox potential of glutathione, apoptosis (caspase-3, caspase-8, and caspase-9) and alveolarization index (histology: number of intercepts/mm).

Results: Compared with IL, SMOF induces a greater oxidation of redox potential (-200 ± 1 versus [vs] -205 ± 1 mV), apoptosis (caspase-3: 0.27 ± 0.04 vs 0.16 ± 0.02; caspase-9: 0.47 ± 0.03 vs 0.30 ± 0.03), and a lower alveolarization index (27.2 ± 0.8 vs 30.0 ± 0.9). Photo-protection prevented activation of caspase-9 and was statistically without effect on redox potential, caspase-3, and alveolarization index.

Conclusion: In our model, SMOF is pro-oxidant and induces hypo-alveolarization following exaggerated apoptosis. These results highlight the need for further studies before introducing SMOFLipid in standard neonatal care.

Keywords: alveolarization; apoptosis; bronchopulmonary dysplasia; guinea pig; lipid emulsion; oxidative stress; parenteral nutrition; preterm infants.