The sphingosine-1-phosphate receptor agonist FTY720 dose dependently affected endothelial integrity in vitro and aggravated ventilator-induced lung injury in mice

Holger Christian Müller (1) , Andreas Christian Hocke (1) , Katharina Hellwig (1) , Birgitt Gutbier (1) , Harm Peters (2) , Stefanie Maria Schönrock (1) , Thomas Tschernig (3) , Andreas Schmiedl (4) , Stefan Hippenstiel (1) , Philippe Dje N'Guessan (1) , Simone Rosseau (1) , Norbert Suttorp (1) , Martin Witzenrath (1)

1 Department of Infectious Diseases and Pulmonary Medicine
2 Department of Nephrology
3 Saarland University Faculty of Medicine
4 MHH - Medizinische Hochschule Hannover = Hannover Medical School

Lung barrier protection by Sphingosine-1 Phosphate (S1P) has been demonstrated experimentally, but recent evidence suggests barrier-disruptive properties of high systemic S1P concentrations. The S1P analog FTY720 recently gained an FDA approval for treatment of multiple sclerosis. In case of FTY720 treated patients experiencing multiple organ dysfunction syndrome the drug may accumulate due to liver failure, and the patients may receive ventilator therapy. Whereas low doses of FTY720 enhanced endothelial barrier function, data on effects of increased FTY720 concentrations are lacking. We measured transendothelial resistance (TER) of human umbilical vein endothelial cell (HUVEC) monolayers, performed morphologic analysis and measured apoptosis by TUNEL staining and procaspase-3 degradation in HUVECs stimulated with FTY720 (0.01-100 μM). Healthy C57BL/6 mice and mice ventilated with 17ml/kg tidal volume and 100% oxygen for 2 h were treated with 0.1 or 2 mg/kg FTY720 or solvent, and lung permeability, oxygenation and leukocyte counts in BAL and blood were quantified. Further, electron microscopic analysis of lung tissue was performed. We observed barrier protective effects of FTY720 on HUVEC cell layers at concentrations up to 1 μM while higher concentrations induced irreversible barrier breakdown accompanied by induction of apoptosis. Low FTY720 concentrations (0.1 mg/kg) reduced lung permeability in mechanically ventilated mice, but 2 mg/kg FTY720 increased pulmonary vascular permeability in ventilated mice accompanied by endothelial apoptosis, while not affecting permeability in non-ventilated mice. Moreover, hyperoxic mechanical ventilation sensitized the pulmonary vasculature to a barrier disrupting effect of FTY720, resulting in worsening of ventilator induced lung injury. In conclusion, the current data suggest FTY720-induced endothelial barrier dysfunction, which was probably caused by proapoptotic effects and enhanced by mechanical ventilation.

Mots clés: Ventilator-induced lung injury; FTY720; Vascular permeability; acute lung injury; apoptosis

Domaines: Pneumologie et système respiratoire

Holger Christian Müller, Andreas Christian Hocke, Katharina Hellwig, Birgitt Gutbier, Harm Peters, et al.. The sphingosine-1-phosphate receptor agonist FTY720 dose dependently affected endothelial integrity in vitro and aggravated ventilator-induced lung injury in mice. Pulmonary Pharmacology & Therapeutics, 2011, ⟨10.1016/j.pupt.2011.01.017⟩. ⟨hal-00753947⟩