title: Effect of serum lipoproteins and cholesterol on an exogenous pulmonary surfactant. ESR analysis of structural changes and their relation with surfactant activity.
abstract: The study of structural changes in the surfactant may help to understand the mechanisms by which the surfactant is inactivated by serum. Here, we compared the in vitro effects of serum, albumin, lipoproteins (VLDL, LDL, HDL) and cholesterol on the dynamic and structural properties of surfactant suspensions by electronic spin resonance and surface tension measurements. Our results showed that albumin seems to be responsible for macrostructure disaggregation and increased rigidity in the hydrophobic region, but it did not affect surfactant activity. Fluidity in the polar area seems to be critical for proper physiological activity, and the changes induced by serum observed in this area would be generated by HDL or cholesterol, but the amount of cholesterol transferred by serum is not significant. Statistical analysis showed that surfactant activity correlated with the fluidity in the polar area but not with that in the hydrophobic region. We obtained strong evidence that among all the serum components tested, HDL is the one that causes the structural changes that compromise surfactant performance.
authors.affiliation: Cátedra de Física, Departamento de Fisicomatemática, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina. Electronic address: marga@ffyb.uba.ar.
authors.forename: María
authors.initials: M
authors.lastname: Martínez Sarrasague
authors.forename: Alejandra
authors.initials: A
authors.lastname: Cimato
authors.forename: Lidia
authors.initials: L
authors.lastname: Piehl
authors.forename: Fernando
authors.initials: F
authors.lastname: Brites
authors.forename: Graciela
authors.initials: G
authors.lastname: Facorro
mesh_terms: D002784:Cholesterol / Q000097:blood*; D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D008074:Lipoproteins / Q000097:blood*; D011663:Pulmonary Surfactants / Q000737:chemistry* / Q000378:metabolism; D013500:Surface Tension / Q000187:drug effects
chemical_list: D008074:Lipoproteins; D011663:Pulmonary Surfactants; D002784:Cholesterol
keywords: Cholesterol; ESR; Exogenous pulmonary surfactant; Serum lipoproteins; Structural changes