Extracellular matrix and mechanical ventilation in healthy lungs: back to baro/volotrauma?
OBJECTIVE
The extracellular matrix plays an important role in the biomechanical behaviour of the lung parenchyma. The matrix is composed of a three-dimensional fibre mesh filled with different macromolecules, including proteoglycans which have important functions in many lung pathophysiological processes, as they regulate tissue hydration, macromolecular structure and function, response to inflammatory agents, and tissue repair and remodelling. The aim of this review is to describe the role of mechanical ventilation on pulmonary extracellular matrix structure and function.


RESULTS
Recent experimental and clinical data suggest that in healthy lungs, mechanical ventilation with tidal volume ranging between 7 and 12 ml/kg in the absence of positive end-expiratory pressure may lead to endothelial, extracellular matrix and peripheral airways damage without major inflammatory response. Several mechanisms may explain damage to the lung structure induced by mechanical ventilation: regional overdistension, 'low lung volume' associated with tidal airway closure, and inactivation of surfactant.


CONCLUSIONS
Tidal volume reduction to 6 ml/kg may be useful during mechanical ventilation of healthy lungs. The study of the extracellular matrix may be useful to better understand the pathophysiology of ventilator-induced lung injury in healthy and diseased lungs.
Pelosi
Paolo
P
Department of Environment, Health, and Safety, University of Insubria-Circolo and Fondazione Macchi Hospital, Varese, Italy. ppelosi@hotmail.com
Negrini
Daniela
D
D000818:Animals; D001469:Barotrauma / Q000503:physiopathology / Q000517:prevention & control*; D002986:Clinical Trials as Topic; D005109:Extracellular Matrix / Q000502:physiology* / Q000648:ultrastructure*; D006801:Humans; D008168:Lung / Q000502:physiology*; D011175:Positive-Pressure Respiration; D011509:Proteoglycans / Q000378:metabolism; D012121:Respiration, Artificial / Q000009:adverse effects*; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D013990:Tidal Volume
D011509:Proteoglycans