Abstract
Background: Bronchial muscle tone and hyperresponsiveness (BHR) are essential features of asthma and lung disease after preterm birth. Methacholine (Mtc) is a direct parasympathetic airway smooth muscle (ASM) constrictor. Nitric oxide (NO) relaxes ASM, is synthesized from arginine and inhibited by the arginine metabolite ADMA which is negatively correlated to birth weight (BW) and higher in asthma.
Aim: Study lung function and NO metabolites vs gestational age at birth (GA), bronchopulmonary dysplasia (BPD) and BW appropriate or <10th centile for GA (AGA or SGA) in preterm children.
Methods: Lung function, Mtc-BHR, FeNO, Arginine, ADMA, SDMA were determined in a population-based sample of 57 preterm-born 11 year old children and matched normal BW term-controls.
Results: Growth restricted children born preterm had markedly increased Mtc-BHR and higher levels of arginine, ADMA and SDMA, which may affect NO production. Mtc-BHR and ADMA correlated significantly.
Conclusion: If BHR and NO metabolism are similarly linked to SGA in the general population, it can be an inborn cause rather than a consequence of asthma.
Termborn AGA | Preterm born | |||
n=54 | AGA (n=37) | SGA (n=20) | P value | |
GA, weeks | 26.1 (1.1) | 28.0 (1.7) | <0.001 | |
BW, g | 3701 (434) | 918 (152) | 724 (143) | <0.001 |
BPD, n (%) | NA | 23 (62%) | 8 (40%) | 0.11 |
zFEV1 | -0.31 (0.97) | -0.49 (0.89) | -0.96 (0.96) | 0.03 |
Mtc dose response | 3.5 | 8.7 | 28.8 | <0.001 |
Arginine µmol/L | 90.3 (15.6) | 97.8 (18.4) | 103.0 (23.5) | 0.03 |
ADMA, mg/L* | 0.65 (0.07) | 0.66 (0.07) | 0.71 (0.07) | 0.003 |
SDMA, mg/L** | 0.55 (0.08) | 0.56 (0.07) | 0.61 (0.09) | 0.01 |
Arg/ADMA ratio | 140.9 (24.1) | 147.9 (23.1) | 143.8 (23.5) | 0.46 |
FeNO# | 16.2 (17.6) | 12.8 (11.1) | 10.7 (5.4) | 0.32 |
*Asymmetric **Symmetric dimethyl arginine; #Fractional exhaled NO
- Copyright ©the authors 2016