Surfactant protein A in the course of respiratory distress syndrome

Abstract

Abstract. Surfactant-associated protein (SP-A) was measured in tracheal aspirates of ventilated infants with (n = 51) and without (n = 21) respiratory distress syndrome (RDS). SP-A concentrations in samples collected after birth were significantly lower in RDS than in infants ventilated for other reasons than RDS (median 0.03 vs. 1.60 gg/ml). As a biochemical test to diagnose RDS early after birth, the sensitivity of measuring SP-A in tracheal aspirates was 87% and specificity 81%. SP-A content in tracheal aspirates of infants with RDS was monitored during the first 7 days of life. A significant (P < 0.001) increase within the first 4 days was found in those infants who survived, whereas no such change was found in those infants who died.

Bronchoalveolar Lavage Surfactant Protein A, B, and D Concentrations in Preterm Infants Ventilated for Respiratory Distress Syndrome Receiving Natural and Synthetic Surfactants

“…BAL SP-A concentrations rose significantly during the first postnatal week in these infants, in keeping with reports using a more proximal tracheal aspirate method (13,15,16,19,21). Just two reports have previously described postnatal changes in BAL SP-B concentration in RDS (14,16).…”

“…Infants dying of RDS appear to show a failure in the normal postnatal rise in lavage SP-A concentrations (13), and a low SP-A to phospholipid ratio is associated with poor outcome (7). However, all existing reports of lavage SP-A concentrations in preterm infants with RDS (7,(13)(14)(15)(16)(17)(18)(19)(20)(21) have used a technique of tracheal aspiration known to sample proximal airways within the bronchial tree (22). In addition, several of these studies (14 -16, 20, 21) standardized for dilutional effects of lavage using unconventional markers of dilution (23).…”

Increased expression of apoptosis signalling receptors by alveolar macrophages in sarcoidosis

“…In neonates with RDS, the most striking and consistent finding is a lack, or a greatly reduced amount, of phosphatidylglycerol [76,78,80,120] in addition to increased surface tension [120,121] and decreased amounts of total phospholipid and SP-A (table 4) [77,79]. In contrast to most other diseases investigated, studies in neonates have primarily used tracheobronchial aspirates or small-volume lavages instead of BAL.…”

“…The lack of SP-A in infants with RDS increases their susceptibility to surfactant inhibitors [129,133]. With recovery from RDS, the amount of SP-A [77,134,135] and the hydrophobic surfactant proteins increased [135]. The SP-A in infants with RDS exhibited a lesser degree of post-translational modifications than that from controls [134].…”

“…Lastly, the sensitivity and specificity of only a few of the potential variables (e.g. phosphatidylglycerol, lecithin/ sphingomyelin (L/S)-ratio, SP-A) are known for only some specific disease processes [77,129]. Without doubt, an impaired surfactant system will be functionally deficient, but the tools to precisely diagnose this in a noninvasive manner are currently lacking.…”