Interindividual variability in the expression of surfactant protein A and B in the human lung during development

  • F. Cau | flacau@tiscali.it Hospital Nostra Signora di Bonaria, Italy.
  • E. Pisu Hospital Nostra Signora di Bonaria, Italy.
  • C. Gerosa University of Cagliari, Italy.
  • G. Senes University of Cagliari, Italy.
  • F. Ronchi Hospital Nostra Signora di Bonaria, Italy.
  • C. Botta Hospital Nostra Signora di Bonaria, Italy.
  • E. Di Felice University of Cagliari, Italy.
  • F. Uda University of Cagliari, Italy.
  • V. Marinelli University of Cagliari, Italy.
  • G. Faa University of Cagliari, Italy.
  • V. Fanos University of Cagliari, Italy.
  • C. Moretti Sapienza University of Rome, Italy.
  • D. Fanni University of Cagliari, Italy.

Abstract

The surfactant complex, thanks to its multiple actions including decrease of surface- tension and antimicrobial activity, plays a fundamental role in newborn survival, lowering the risk of respiratory distress syndrome. The aim of this work was to determine if the synthesis of two surfactant proteins (SP), SPA and pro-SPB, shows some inter-individual variability during lung development in the intrauterine life. Immunoreactivity for SPA and pro-SPB was investigated in the lungs of  40 subjects, including 15 fetuses, ranging from 14 to 22 weeks of gestation, and 25 neonates, from 24 to 41 weeks. Lung samples were formalin fixed, paraffin-embedded and routinely processed. SPA and pro-SPB were detected utilizing commercial antibodies.  A semi-quantitative grading system (1 to 4) was applied, based on the number of reactive cells and the intensity of immunostaining. Surfactant protein immunostaining was found in  three compartments: bronchi, bronchioles and alveoli, starting from 14 weeks of gestation in the bronchial epithelium and from the 21st week in the alveolar spaces. Differences were found regarding SPA and pro-SPB expression in the vast majority of subjects: in some lungs, SPA was more expressed whereas in others pro-SPB showed an higher degree of immunoreactivity. The expression of both surfactant proteins was not strictly correlated with gestational age. Whereas the highest levels of reactivity were detected in at term neonates, on the other hand one case with grade 3 was detected at 22 weeks and one negative case for both proteins was observed at 31 weeks. Our data clearly show a marked inter-individual variability regarding the production of SPA and pro-SPB and suggest the existence of other epigenetic factors, acting during gestation, that might influence surfactant production and, consequently, the survival potential of  neonates at birth. 

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Published
2016-09-26
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Original Papers
Keywords:
Surfactant, lung, immunohistochemistry, development.
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How to Cite
Cau, F., Pisu, E., Gerosa, C., Senes, G., Ronchi, F., Botta, C., Di Felice, E., Uda, F., Marinelli, V., Faa, G., Fanos, V., Moretti, C., & Fanni, D. (2016). Interindividual variability in the expression of surfactant protein A and B in the human lung during development. European Journal of Histochemistry, 60(3). https://doi.org/10.4081/ejh.2016.2678