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Surfactant proteins (SPs) are important lipoprotein complex components, expressed in alveolar epithelial cells type II (AEC-II), and playing an essential role in maintenance of alveolar integrity and host defence. Because expressions of SPs are regulated by cyclic adenosine monophosphate (cAMP), we hypothesized that phosphodiesterase (PDE) inhibitors, influence SP expression and release. Analysis of PDE activity of our AEC-II preparations revealed that PDE4 is the major cAMP hydrolysing PDE in human adult AEC-II. Thus, freshly isolated human AEC-II were stimulated with two different concentrations of the PDE4 inhibitor roflumilast-N-oxide (3 nM and 1 µM) to investigate the effect on SP expression. SP mRNA levels disclosed a large inter-individual variation. Therefore, the experiments were grouped by the basal SP expression in low and high expressing donors. AEC-II stimulated with Roflumilast-N-oxide showed a minor increase in SP-A1, SP-C and SP-D mRNA mainly in low expressing preparations. To overcome the effects of different basal levels of intracellular cAMP, cyclooxygenase was blocked by indomethacin and cAMP production was reconstituted by prostaglandin E2 (PGE2). Under these conditions SP-A1, SP-A2, SP-B and SP-D are increased by roflumilast-N-oxide in low expressing preparations. Roflumilast-N-oxide fosters the expression of SPs in human AEC-II via increase of intracellular cAMP levels potentially contributing to improved alveolar host defence and enhanced resolution of inflammation.

Flush perfusion of the pulmonary artery with organ protection solution is a standard procedure before lung explantation. However, rapid flush perfusion may cause pulmonary oedema which is deleterious in the lung transplantation setting. In this study we tested the hypotheses that high pulmonary perfusion pressure contributes to the development of pulmonary oedema and positive end-expiratory pressure (PEEP) counteracts oedema formation. We expected oedema formation to increase weight and decrease compliance of the lungs on the basis of a decrease in alveolar volume as fluid replaces alveolar air spaces. The pulmonary artery of 28 isolated porcine lungs was perfused with a low-potassium dextrane solution at low (mean 27 mmHg) or high (mean 40 mmHg) pulmonary artery pressure (PAP) during mechanical ventilation at low (4 cmH(2)O) or high (8 cmH(2)O) PEEP, respectively. Following perfusion and storage, relative increases in lung weight were smaller (p0.05) during perfusion at low PAP (62 +/- 32% and 42 +/- 26%, respectively) compared to perfusion at high PAP (133 +/- 54% and 87 +/- 30%, respectively). Compared to all other PAP-PEEP combinations, increases in lung weight were smallest (44 +/- 9% and 27 +/- 12%, respectively), nonlinear intratidal lung compliance was largest (46% and 17% respectively, both p0.05) and lung histology showed least infiltration of mononuclear cells in the alveolar septa, and least alveolar destruction during the combination of low perfusion pressure and high PEEP. The findings suggest that oedema formation during pulmonary artery flush perfusion in isolated and ventilated lungs can be reduced by choosing low perfusion pressure and high PEEP. PAP-PEEP titration to minimize pulmonary oedema should be based on lung mechanics and PAP monitoring.

Recruitment/Derecruitment of alveoli during mechanical ventilation plays an important role in the development of ventilator induced lung injury (VILI).

Cladosporium is the fungal genus most frequently encountered in both outdoor and indoor air. However it is also one of the most common pathogens of phaeohyphomycosis. Phaeohyphomycosis has become increasingly recognized in a wide variety of clinical syndromes.

Stretch during mechanical ventilation induces stress on alveolar epithelial cells (AEC). Experimental mechanostimulation of AEC mimics this stress and helps to understand fundamental processes in consequence of stretch.

The optimal setting of positive end-expiratory pressure (PEEP) during mechanical ventilation in the ICU is still an open problem [1]. Recruitment processes are important influence factors that are difficult to measure in patients [2,3]. It is proposed to use lung sound analysis to identify recruitment during mechanical ventilation.