Metabolomic profile at birth, bronchiolitis and recurrent wheezing

Understanding whether and how genetic and environmental factors in the pre- and post-natal period influence the development of respiratory and allergic diseases in the first years of life represents an open field of research, of growing interest in recent years.

The "omics" sciences are one of the most innovative approaches in this area, and among them is metabolomics, which studies the differences in metabolic profiles between different populations.

In this prospective longitudinal study conducted by the Hospital - University of Padua together with the Pediatric Research Institute - Città della Speranza Foundation, the urinary metabolomic profile of 205 healthy term newborns was analyzed by mass spectrometry. They were followed up to the age of 3 years, with regard to the development of bronchiolitis or wheezing episodes (defined as recurrent if in number greater than or equal to 3).

35 of 205 patients (17%) presented with bronchiolitis in the first year of life, and of these, 11 (31%) had episodes of recurrent wheezing in the following years. In the group of children who did not have bronchiolitis (83%), 41 of 170 had at least one episode of wheezing in the first 3 years (in 13 of them wheezing was recurrent).

There were no significant differences in the urinary metabolomic profile at birth between patients who developed bronchiolitis and those who did not, nor between those who did or did not develop recurrent wheezing following the first episode of bronchiolitis.

However, comparing the profiles of patients who presented recurrent wheezing (not preceded by bronchiolitis) with those who did not register any episode of wheezing in the first three years of life, it emerged that in the latter the levels of xanthine, uric acid, leucine, L-tyrosine, L-pyroglutamic acid and L-ornithine were significantly higher.

The pathophysiological cause for these differences is not yet clear. Neither it’s defined whether high levels of these metabolites represent a protective factor for the development of wheezing or if their reduction is a risk factor.

However, these results underline that there could be a specific metabolic background, present since birth and still being studied, which predisposes to the development of recurrent wheezing not associated with bronchiolitis in the first years of life.

Bibliography
Carraro S, Ferraro VA, Maretti M, Giordano G, Pirillo P, Stocchero M, Zanconato S, Baraldi E. Metabolomic Profile at Birth, Bronchiolitis and Recurrent Wheezing: A 3-Year Prospective Study. Metabolites. 2021 Nov 30;11(12):825. doi: 10.3390/metabo11120825. PMID: 34940583; PMCID: PMC8706329.