Single nucleotide polymorphisms in surfactant protein A1 are not associated with a lack of responsiveness to antenatal steroid therapy in a pregnant sheep model. Issue 19 (5th October 2022)

• Record Type: Journal Article
• Authors: Takahashi, Tsukasa; Takahashi, Yuki; Fee, Erin L.; Usuda, Haruo; Furfaro, Lucy; Newnham, John P.; Jobe, Alan H.; Kemp, Matthew W.
• Is Part Of: Physiological reports. Volume 10:Issue 19(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-05
• Subjects: antenatal corticosteroids -- lung maturation -- preterm birth -- sheep -- single nucleotide polymorphisms; Physiology -- Periodicals; 571
• DOI: 10.14814/phy2.15477
• Languages: English
• ISSNs: 2051-817X

Abstract

Abstract: Treatment with antenatal steroids (ANS) is standard practice for reducing the risk of respiratory distress in the preterm infant. Despite clear overall benefits when appropriately administered, many fetuses fail to derive benefit from ANS therapies. In standardized experiments using a pregnant sheep model, we have demonstrated that around 40% of ANS‐exposed lambs did not have functional lung maturation significantly different from that of saline‐treated controls. Surfactant protein A is known to play an important role in lung function. In this genotyping study, we investigated the potential correlation between polymorphisms in SFTPA1, messenger RNA and protein levels, and ventilation outcomes in animals treated with ANS. 45 preterm lambs were delivered 48 h after initial ANS therapy and 44 lambs were delivered 8 days after initial ANS therapy. The lambs were ventilated for 30 min after delivery. SFTPA1 mRNA expression in lung tissue was not correlated with arterial blood PaCO2 values at 30 min of ventilation in lambs delivered 48 h after treatment. SFTPA1 protein in lung tissue was significantly correlated with PaCO2 at 30 min of ventilation in lambs ventilated both 48 h and 8 days after ANS treatment. Six different single nucleotide polymorphisms (SNPs) in the Ovis aries SFTPA1 sequence were detected by Sanger Sequencing. No individual SNPs or SNP haplotypes correlated with alterations in PaCO2 at 30 min of ventilation or SFTPA1 protein levels in the lung. For the subset of animals analyzed in the present study, variable lung maturation responses to ANS therapy were not associated with mutations in SFTPA1 . Abstract : In the sheep pregnant model, fetal lung SP‐A protein concentration but not mRNA expression was correlated to the fetal lung maturation after ANS treatment. However, none of the SNPs in the SP‐A gene were associated with fetal lung maturation or variability of ANS treatment responsiveness.