From: Surfactant alteration and replacement in acute respiratory distress syndrome
Mediator | Effects |
---|---|
Phospholipases | Â |
   PL-A2, PL-C | Generation of lysophospholipids [94] |
 | Generation of free fatty acids [95] |
 | Loss of surface activity [94] |
 | Higher sensitivity towards inhibition by plasma proteins [96] |
Cytokines | Â |
   TNF-α | Pretranslational inhibitory effect on the expression of SP-A and SP-B [97] |
Proteases | Â |
   Elastase | Degradation of SP-A, indirect evidence for degradation of SP-B and SP-C; loss of surface activity [98] |
 | Degradation of SP-A, SP-B, SP-C [99] |
   Trypsin | Degradation of SP-A [99] |
   Surfactant 'convertase' | Increased conversion of large to small surfactant aggregates [32] |
Oxygen radicals | Â |
   ROS, ozone | |
 | Induction of lipid peroxidation [101] |
 | Inhibition of SP-A self-aggregation [102] |
Lipid mediators | Â |
   Arachidonic acid | Decrease in surface activity [101] |
   Activated neutrophils (PMNs) | Decrease in surface activity [100] |
 | Degradation of SP-A [100] |