Relationship between pressure-volume curve and markers for collagen turn-over in early acute respiratory distress syndrome.
OBJECTIVE
In acute respiratory distress syndrome, the relationships between changes in the elastic behavior of the respiratory system and biological markers of extra-cellular matrix or surfactant turn-over could give some insights into its pathophysiological determinants.


METHODS
In 17 patients with acute respiratory distress syndrome, we assessed the relationship between chord compliance measured on pressure-volume curves obtained at two levels of positive end-expiratory pressure (0 and 10[Symbol: see text]cm[Symbol: see text]H(2)O) and biological markers of collagen turn-over or surfactant degradation in bronchoalveolar lavage fluid obtained simultaneously in the early phase of the disease (first 4 days).


RESULTS
The compliance of the respiratory system obtained from the pressure-volume curves was significantly correlated with markers for collagen turn-over (type III procollagen peptide and matrix metalloproteinase 2) and with markers of surfactant degradation (type-IIA secretory phospholipase A2). The correlations were stronger when the curve was traced from positive end-expiratory pressure, suggesting that this condition may improve the assessment of tissue mechanics. A logarithmic relationship best described the correlation between compliance and type III procollagen peptide, in agreement with a collagen-dependent model of maximal distension. The marker for surfactant degradation was associated with ongoing alveolar inflammation (cellularity of bronchoalveolar lavage fluid and tumor necrosis factor-alpha concentration). Interleukin-10, an anti-inflammatory mediator, showed no correlation with compliance.


CONCLUSIONS
These preliminary data suggest that a severe reduction in compliance in the early phase of acute respiratory distress syndrome is associated with both collagen deposition and surfactant degradation.
Unité INSERM U615-Université Paris 12, Faculté de Médecine de Créteil, Paris, France.
Alexandre
A
Demoule
François
F
Decailliot
Bjorn
B
Jonson
Christo
C
Christov
Bernard
B
Maitre
Lhousseine
L
Touqui
Laurent
L
Brochard
Christophe
C
Delclaux
D000328:Adult; D000368:Aged; D000399:Air Pressure; D015415:Biomarkers; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D024043:Collagen Type II / Q000032:analysis* / Q000378:metabolism; D024061:Collagen Type III / Q000032:analysis* / Q000378:metabolism; D005260:Female; D005602:France; D006801:Humans; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012128:Respiratory Distress Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D015656:Respiratory Mechanics / Q000502:physiology
D015415:Biomarkers; D024043:Collagen Type II; D024061:Collagen Type III