Glucocorticoid signature of preterm infants developing bronchopulmonary dysplasia

Systemic inflammation plays a key role in the development of bronchopulmonary dysplasia (BPD). Cortisol is known to dampen inflammation. However, adrenal function following preterm birth is characterized by insufficient cortisol levels for the degree of inflammation, and a relative abundancy of cortisol precursors. We investigated whether this pattern could contribute to the development of BPD in preterm infants born <30 weeks of gestation.

Cortisol, cortisone, 17-OH progesterone (17-OHP) and 11-deoxycortisol were measured in serum obtained at postnatal days 1, 3, 7, 14 and 28, using liquid-chromatography-tandem-mass-spectrometry. The presence of BPD was ascertained at 36 weeks postmenstrual age.

Sixty-five infants were included for analysis, of whom 32 (49%) developed BPD. Preterm infants developing BPD, as compared to those without BPD, had higher levels of 17-OHP, 11-deoxycortisol and cortisone relative to cortisol in their first week of life, but not at birth or beyond day 7.

Preterm infants developing BPD had higher levels of cortisol precursors and cortisone relative to cortisol in their first week of life than infants without BPD. These findings suggest that BPD is preceded by an activated hypothalamus-pituitary-adrenal axis that could not meet the high cortisol demands, which may predispose to inflammation and BPD.

Relative adrenal insufficiency is common in the first weeks after preterm birth, resulting in insufficient cortisol production for the degree of inflammation and a relative abundance of cortisol precursors; Whether this pattern contributes to the development of bronchopulmonary dysplasia (BPD) is not fully elucidated, since most studies focused on cortisol levels; Preterm infants developing BPD had higher levels of cortisol precursors and cortisone relative to cortisol in the first week of life, suggestive of a hypothalamus-pituitary-adrenal-axis activation during BPD development which cannot meet the high cortisol demands in tissues; This glucocorticoid pattern is likely to dispose to inflammation and BPD.