ABSTRACT
I. Introduction 359
II. Physiological Function of Pulmonary Surfactant 360
III. Surfactant Composition 362
IV. Surfactant Metabolism 363
V. Acute Lung Injury 363
VI. Alterations of Surfactant During ALI 365
VII. Mechanisms by Which Alterations of Surfactant Occur 366
VIII. Mechanisms by Which Alterations of Surfactant
Lead to a Loss in Function 368
IX. Exogenous Surfactant Administration in ALI 368
X. Conclusions and Future Directions 371
Acknowledgments 372
References 372
I. Introduction
Pulmonary surfactant is essential for normal lung function (1). This physiological
importance is obvious from the observed lung dysfunction in premature babies
deficient in lung surfactant and the subsequent improvement in lung function fol-
lowing exogenous surfactant supplementation (2,3). In fact, the clinical term for
lung impairment in premature neonates due to surfactant deficiency is neonatal
respiratory distress syndrome (NRDS). The association of surfactant deficiency
with this clinical syndrome has been the main rationale for the extensive
studies on various aspects of the pulmonary surfactant system over the last 40
years (4,5). However, surfactant deficiency is not the only clinical situation in
which the pulmonary surfactant contributes to physiological abnormalities.
Several clinical conditions have been associated with alterations of the pulmon-
ary surfactant system including acute lung injury (ALI) (6,7). In this chapter, we
will focus on the role of surfactant in the development and treatment of ALI.
First, we will briefly review the pulmonary surfactant system and ALI. This
will be followed by a description of the alterations of surfactant in ALI. The
rest of the chapters will then focus on the consequences of surfactant impairment
in ALI, the mechanisms by which surfactant impairment occurs, and the potential
of surfactant therapy for ALI. These discussions will be presented from a broad
physiological-biochemical perspective. For further details on specific aspects,
the reader will be referred to a number of recent review articles as well as
other chapters in the current volume.
