Proteína surfactante pulmonar tipo B en circulación periférica y deterioro funcional en pacientes con insuficiencia cardiaca crónica

Fetal and neonatal samples of a precursor surfactant protein B inversely related to gestational age

Background

Alveolar–capillary membrane leaks can increase the amount of surfactant protein B (SP-B) in the bloodstream. The purpose of this study was to measure the concentration of C-proSP-B, a SP-B precursor that includes C-terminal domains, in various body fluids of newborn infants and determine its dependence on gestational age.

Methods

C-pro-SPB was measured in amniotic fluid and umbilical cord blood at birth, and in peripheral blood and urine on postnatal day 3 in 137 newborn infants with a median birth weight of 2015 g (range, 550–4475 g) and gestational age of 34 weeks (range, 23–42 weeks).

Results

C-proSP-B levels differed more than 100-fold among samples. The levels (median; interquartile range) were highest in peripheral blood (655.6 ng/mL; 419.0-1467.0 ng/mL) and lowest in urine (3.08 ng/mL; 2.96-3.35 ng/mL). C-proSP-B levels in amniotic fluid (314.9 ng/mL; 192.7–603.6 ng/mL) were approximately half of those in peripheral blood. In cord blood C-proSP-B was slightly lower (589.1 ng/mL; 181.2-1129.0 ng/mL) compared with peripheral blood. C-proSP-B levels significantly increased in all the fluids sampled except urine with decreasing gestational age (p < 0.001).

Conclusions

This novel assay allows for the quantitative measurement of C-proSP-B in blood and amniotic fluid. The dependence of C-proSP-B on gestational age may hamper its use for the detection of alveolar leaks in preterm newborns.

Unifying thoracic biomarkers: surfactant protein-D and beyond

Chronic obstructive pulmonary disease (COPD) is a progressive disorder that affects 300 million people worldwide and is responsible for 3 million deaths annually. Currently, there are no accepted biomarkers of COPD, which has impaired drug development and management of patients with COPD. Pneumoproteins, which are proteins synthesized predominantly in the lungs, are promising blood biomarkers because they have high specificity for lung disease. The most promising is surfactant protein-D, which is synthesized largely in Type 2 pneumocytes, and its blood concentrations have been associated with COPD and with certain clinical end points such as mortality. In this paper, we discuss surfactant protein-D and other pneumoproteins as promising biomarkers of COPD.