Oxidative stress and increased type-IV collagenase levels in bronchoalveolar lavage fluid from newborn babies.
Oxidative stress may increase lung permeability by up-regulation of matrix-metalloproteinase-9 (MMP-9), a type-IV collagenase that can disrupt alveolar basement membranes. We have compared a marker of oxidative stress (protein carbonyl residues) with levels of MMP-9 and its inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1), in bronchoalveolar lavage samples from newborn babies. Bronchoalveolar lavage samples (n = 87, two from each time point) were taken in the first 6 postnatal days from 41 ventilated babies: 18 of <29 wk gestation, 10 of 29-36 wk, 9 term with persistent fetal circulation, and 4 term without lung disease. Respiratory disease severity at the time of bronchoalveolar lavage was assessed using the arterial-alveolar oxygen tension ratio. One sample from each time point was used for the measurement of MMP-9 by zymography and TIMP-1 by ELISA. The second sample was used to measure carbonyl group concentrations, also using an ELISA. Correlations were calculated between protein carbonyls, arterial-alveolar oxygen tension ratio, and MMP-9 and TIMP-1 concentrations. Significant correlations were found between carbonyl concentrations and arterial-alveolar oxygen tension ratio (r = -0.325, p = 0.0031, n = 81), MMP-9 (r = 0.331, p < 0.0029, n = 79), and TIMP-1 (r = 0.436, p < 0.0001, n = 87). Worsening respiratory disease in newborn babies is associated with increased carbonyl concentrations in neonatal bronchoalveolar lavage fluid, and these correlated with MMP-9 and TIMP-1 levels. Increased oxidative stress may damage the lung by increasing type-IV collagenase activity, causing disruption of the extracellular matrix.
Schock
B C
BC
Department of Clinical Biochemistry, Institute of Clinical Science, The Queen's University of Belfast, Belfast BT12 6BJ, Northern Ireland, UK.
Sweet
D G
DG
Ennis
M
M
Warner
J A
JA
Young
I S
IS
Halliday
H L
HL
D001992:Bronchoalveolar Lavage Fluid; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007231:Infant, Newborn; D008315:Malondialdehyde / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D018384:Oxidative Stress; D011446:Prospective Studies; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism
D019715:Tissue Inhibitor of Metalloproteinase-1; D008315:Malondialdehyde; D020780:Matrix Metalloproteinase 9