Cytosolic phospholipase A2 and arachidonic acid metabolites modulate ventilator-induced permeability increases in isolated mouse lungs.

We previously reported that the cytosolic phospholipase A(2) (cPLA2) pathway is involved in ventilator-induced lung injury (VILI) produced by high peak inflation pressures (PIP) (J Appl Physiol 98: 1264-1271, 2005), but the relative contributions of the various downstream products of cPLA2 on the acute permeability response were not determined. Therefore, we investigated the role of cPLA2 and the downstream products of arachidonic acid metabolism in the high-PIP ventilation-induced increase in vascular permeability. We perfused isolated mouse lungs and measured the capillary filtration coefficient (K(fc)) after 30 min of ventilation with 9, 25, and 35 cmH2O PIP. In high-PIP-ventilated lungs, K(fc) increased significantly, 2.7-fold, after ventilation with 35 cmH2O PIP compared with paired baseline values and low-PIP-ventilated lungs. Also, increased phosphorylation of lung cPLA2 suggested enzyme activation after high-PIP ventilation. However, treatment with 40 mg/kg arachidonyl trifluoromethyl ketone (an inhibitor of cPLA2) or a combination of 30 microM ibuprofen [a cyclooxygenase (COX) inhibitor], 100 microM nordihydroguaiaretic acid [a lipoxygenase (LOX) inhibitor], and 10 microM 17-octadecynoic acid (a cytochrome P-450 epoxygenase inhibitor) prevented the high-PIP-induced increase in K(fc). Combinations of the inhibitors of COX, LOX, or cytochrome P-450 epoxygenase did not prevent significant increases in K(fc), even though bronchoalveolar lavage levels of the COX or LOX products were significantly reduced. These results suggest that multiple mediators from each pathway contribute to the acute ventilator-induced permeability increase in isolated mouse lungs by mutual potentiation.

Clinical analysis of patients treated with afatinib for advanced non-small cell lung cancer: A Nagano Lung Cancer Research Group observational study.

BACKGROUND: Afatinib has been available in Japan for the treatment of epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) since May 2014. We conducted an observational study in patients treated with afatinib in Nagano prefecture, focusing on response and associated toxicities. METHODS: We analyzed the clinical records of NSCLC patients treated with afatinib between May 2014 and February 2015. RESULTS: The records of a total of 73 patients (27 men, 46 women) with a median age of 69 years (range: 42-85 years) were analyzed. Afatinib was administered to 11 patients as a first-line therapy, but it was predominantly administered as a fifth-line or beyond therapy (32 cases, 43.8%). The overall response rates for afatinib as a first-line therapy and beyond second-line therapy were 80% (95% confidence interval [CI]: 55.2-100.0%) and 27.1% (95% CI: 14.5-39.7%), respectively. The main toxicities grade >3 included diarrhea (8.2%), skin rash (6.8%), nausea (6.8%), and appetite loss (6.8%). A low body surface area (BSA) (<1.5m2) was significantly associated with a higher frequency of diarrhea grade >2, compared with a higher BSA (≥ 1.5m2). Forty-eight patients (63.0%) were treated without a dose reduction of afatinib. CONCLUSIONS: Although the survival benefit with afatinib remains unclear, our observational analysis demonstrated the feasibility of using afatinib for EGFR-mutated NSCLC in clinical practice. In particular, a relatively high level of drug delivery is possible. In addition, a lower BSA may be a predictor of diarrhea in patients treated with afatinib.

Clara cell secretory protein and phospholipase A2 activity modulate acute ventilator-induced lung injury in mice.

Lung vascular permeability is acutely increased by high-pressure and high-volume ventilation. To determine the roles of mechanically activated cytosolic PLA2 (cPLA2)and Clara cell secretory protein (CCSP), a modulator of cPLA2 activity, we compared lung injury with and without a PLA2 inhibitor in wild-type mice and CCSP-null mice (CCSP-/-) ventilated with high and low peak inflation pressures (PIP) for 2- or 4-h periods. After ventilation with high PIP, we observed significant increases in the bronchoalveolar lavage albumin concentrations, lung wet-to-dry weight ratios, and lung myeloperoxidase in both genotypes compared with unventilated controls and low-PIP ventilated mice. All injury variables except myeloperoxidase were significantly greater in the CCSP-/- mice relative to wild-type mice. Inhibition of cPLA2 in wild-type and CCSP-/- mice ventilated at high PIP for 4 h significantly reduced bronchoalveolar lavage albumin and total protein and lung wet-to-dry weight ratios compared with vehicle-treated mice of the same genotype. Membrane phospho-cPLA2 and cPLA2 activities were significantly elevated in lung homogenates of high-PIP ventilated mice of both genotypes but were significantly higher in the CCSP-/- mice relative to the wild-type mice. Inhibition of cPLA2 significantly attenuated both the phospho-cPLA2 increase and increased cPLA2 activity due to high-PIP ventilation. We propose that mechanical activation of the cPLA2 pathway contributes to acute high PIP-induced lung injury and that CCSP may reduce this injury through inhibition of the cPLA2 pathway and reduction of proinflammatory products produced by this pathway.

[A case of acute eosinophilic pneumonia with a disassociation between the KL-6 level and SP-A and SP-D levels in the serum and BAL fluid].

A 45-year-old Japanese electrical engineer was admitted to our department of internal medicine on August 12, 2003, because of a sudden high fever and severe hypoxic respiratory failure. At a barbecue with his family on August 3 beside a nearby river, he had been exposed to the smoke. From August 4 to 11, he had suffered fatigue, fever, dry cough and progressive dyspnea. On admission, his SpO2 was 84%, and computed tomography scanning showed patchy ground glass opacity, thickened bronchial walls, and bilateral pleural effusions. The eosinophil count in the bronchoalveolar lavage fluid (BALF) was increased to 52.4%. Noticeably, the KL-6, SP-A and SP-D levels in the serum were elevated to 197 U/ml, 188 ng/ml and 137 ng/ml, and their levels in BALF had also increased to 225 U/ml, 890 ng/ml and 1110 ng/ml, respectively. The lymphocyte stimulation test was negative, and the cultures of blood and BALF did not grow any pathogens. The patient had smoked 1 pack of per cigarettes day for 25 years and showed no sign of atopic illness. Acute eosinophilic pneumonia (AEP) was diagnosed, and responded dramatically to treatment with oxygen and corticosteroids. The dissociation between the normal KL-6 levels and the elevated SP-A and SP-D levels in the serum and BAL fluid may play an important role in cases of AEP.

Phosphoinositide 3-kinase, Src, and Akt modulate acute ventilation-induced vascular permeability increases in mouse lungs.

To determine the role of phosphoinositide 3-OH kinase (PI3K) pathways in the acute vascular permeability increase associated with ventilator-induced lung injury, we ventilated isolated perfused lungs and intact C57BL/6 mice with low and high peak inflation pressures (PIP). In isolated lungs, filtration coefficients (K(f)) increased significantly after ventilation at 30 cmH(2)O (high PIP) for successive periods of 15, 30 (4.1-fold), and 50 (5.4-fold) min. Pretreatment with 50 microM of the PI3K inhibitor, LY-294002, or 20 microM PP2, a Src kinase inhibitor, significantly attenuated the increase in K(f), whereas 10 microM Akt inhibitor IV significantly augmented the increased K(f). There were no significant differences in K(f) or lung wet-to-dry weight (W/D) ratios between groups ventilated with 9 cmH(2)O PIP (low PIP), with or without inhibitor treatment. Total lung beta-catenin was unchanged in any low PIP isolated lung group, but Akt inhibition during high PIP ventilation significantly decreased total beta-catenin by 86%. Ventilation of intact mice with 55 cmH(2)O PIP for up to 60 min also increased lung vascular permeability, indicated by increases in lung lavage albumin concentration and lung W/D ratios. In these lungs, tyrosine phosphorylation of beta-catenin and serine/threonine phosphorylation of Akt, glycogen synthase kinase 3beta (GSK3beta), and ERK1/2 increased significantly with peak effects at 60 min. Thus mechanical stress activation of PI3K and Src may increase lung vascular permeability through tyrosine phosphorylation, but simultaneous activation of the PI3K-Akt-GSK3beta pathway tends to limit this permeability response, possibly by preserving cellular beta-catenin.

Differential responses of pulmonary endothelial phenotypes to cyclical stretch.

Endothelial phenotypes derived from different pulmonary vascular segments have markedly different permeability response to inflammatory agonists, but their responses to mechanical strain have not been characterized. Therefore, we evaluated the effect of cyclical stretch on cell shape, cell membrane wounding, and junctional beta-catenin in rat pulmonary artery (RPAEC) and microvascular (RPMVEC) endothelial cell monolayers. After 24 h of 24% uniaxial strain at 40 cycles/min, RPAEC but not RPMVEC reoriented transverse to the axis of strain. Total beta-catenin increased in RPAEC but decreased in RPMVEC. Transient plasma membrane wounding was produced by cyclical biaxial strain of 34% or by scratching of monolayers with a needle and was indicated by retention of lysine fixable fluorescent 70 kDa dextran. Junctional beta-catenin was quantified by fluorescence intensity and image analysis. beta-catenin fluorescence was significantly lower in wounded cells than in adjacent uninjured cells in both phenotypes, and the decrease was significantly greater in RPAEC compared to RPMVEC in both scratched (57% vs. 30%) and stretched (55% vs. 37%) cells. Using immunoprecipitation, VE-cadherin-associated beta-catenin decreased significantly in RPAEC (61%) but E-cadherin-associated beta-catenin was not significantly decreased in RPMVEC after 34% biaxial cyclical strain. These data suggest that RPAEC more readily remodel cell-cell adhesions during cyclical stretch than RPMVEC and that a reduced intercellular adhesion adjacent to wounded cells could serve as transvascular leak sites in both phenotypes.