Hidefumi Koh

New bronchoscopic microsample probe to measure the biochemical constituents in epithelial lining fluid of patients with acute respiratory distress syndrome

ObjectiveA noninvasive bronchoscopic microsampling (BMS) probe was developed to sample biochemical constituents of the epithelial lining fluid in small airways. DesignObservational, controlled study. SettingIntensive care unit of academic medical center. Patients and Procedure BMS was applied in a control group of seven patients who had hemoptysis or small solitary peripheral nodules but no hypoxemia or other signs of acute inflammation and in four patients with acute respiratory distress syndrome (ARDS), to test whether BMS can ascertain the presence of acute pulmonary inflammation without complications. Measurements and Results Complications, including a significant decrease in arterial oxygen saturation, were observed neither during nor after BMS. In the ARDS group, albumin, lactate dehydrogenase, interleukin-6, basic fibroblast growth factor, and neutrophil elastase concentrations in epithelial lining fluid were significantly higher (p < .0001, p = .012, p < .0001, p < .0001, and p < .0001, respectively) than in the control group. Serial BMS was safely performed in one patient with ARDS, allowing us to observe a correlation between changes in the concentration of inflammation-related biochemical markers and clinical course of the disease. ConclusionsThese results suggest that BMS is safe and useful to monitor pulmonary biochemical events in ARDS.

Analysis of comorbid factors that increase the COPD assessment test scores

BackgroundThe chronic obstructive pulmonary disease (COPD) Assessment Test (CAT) is a concise health status measure for COPD. COPD patients have a variety of comorbidities, but little is known about their impact on quality of life. This study was designed to investigate comorbid factors that may contribute to high CAT scores.MethodsAn observational study at Keio University and affiliated hospitals enrolled 336 COPD patients and 67 non-COPD subjects. Health status was assessed by the CAT, the St. Georges Respiratory Questionnaire (SGRQ), and all components of the Medical Outcomes Study Short-Form 36-Item (SF-36) version 2, which is a generic measure of health. Comorbidities were identified based on patients’ reports, physicians’ records, and questionnaires, including the Frequency Scale for the Symptoms of Gastro-esophageal reflux disease (GERD) and the Hospital Anxiety and Depression Scale. Dual X-ray absorptiometry measurements of bone mineral density were performed.ResultsThe CAT showed moderate-good correlations with the SGRQ and all components of the SF-36. The presence of GERD, depression, arrhythmia, and anxiety was significantly associated with a high CAT score in the COPD patients.ConclusionsSymptomatic COPD patients have a high prevalence of comorbidities. A high CAT score should alert the clinician to a higher likelihood of certain comorbidities such as GERD and depression, because these diseases may co-exist unrecognized.Trial registrationClinical trial registered with UMIN (UMIN000003470).

Transforming Growth Factor β1 Inhibits Cystic Fibrosis Transmembrane Conductance Regulator-dependent cAMP-stimulated Alveolar Epithelial Fluid Transport via a Phosphatidylinositol 3-Kinase-dependent Mechanism

Exogenous or endogenous β2-adrenergic receptor agonists enhance alveolar epithelial fluid transport via a cAMP-dependent mechanism that protects the lungs from alveolar flooding in acute lung injury. However, impaired alveolar fluid clearance is present in most of the patients with acute lung injury and is associated with increased mortality, although the mechanisms responsible for this inhibition of the alveolar epithelial fluid transport are not completely understood. Here, we found that transforming growth factor β1 (TGF-β1), a critical mediator of acute lung injury, inhibits β2-adrenergic receptor agonist-stimulated vectorial fluid and Cl− transport across primary rat and human alveolar epithelial type II cell monolayers. This inhibition is due to a reduction in the cystic fibrosis transmembrane conductance regulator activity and biosynthesis mediated by a phosphatidylinositol 3-kinase (PI3K)-dependent heterologous desensitization and down-regulation of the β2-adrenergic receptors. Consistent with these in vitro results, inhibition of the PI3K pathway or pretreatment with soluble chimeric TGF-β type II receptor restored β2-adrenergic receptor agonist-stimulated alveolar epithelial fluid transport in an in vivo model of acute lung injury induced by hemorrhagic shock in rats. The results demonstrate a novel role for TGF-β1 in impairing the β- adrenergic agonist-stimulated alveolar fluid clearance in acute lung injury, an effect that could be corrected by using PI3K inhibitors that are safe to use in humans.

Neutrophil depletion attenuates interleukin-8 production in mild-overstretch ventilated normal rabbit lung

ObjectiveAcute lung injury induced by lung overstretch is associated with neutrophil influx, but the pathogenic role of neutrophils in overstretch-induced lung injury remains unclear. DesignTo assess the contribution of neutrophils, we compared the effects of noninjurious large tidal volume (Vt) ventilation on lungs in normal and neutrophil-depleted animals. SettingResearch animal laboratory. SubjectsTwenty-six male Japanese white rabbits. InterventionsAnimals were mechanically ventilated for 4 hrs with one of the three following protocols: large Vt (20 mL/kg), small Vt (8 mL/kg), and large Vt (20 mL/kg) with neutrophil depletion achieved by a single dose of vinblastine injection (0.75 mg/kg) intravenously 4 days before the experiment. Measurements and Main ResultsLarge Vt ventilation produced alveolar neutrophil influx compared with low Vt (p = .002) without evidence of edema or increased epithelial permeability. The neutrophil influx was accompanied by increases in interleukin-8 in bronchoalveolar lavage fluid (p = .04). Immunohistochemistry of large Vt lungs showed increased interleukin-8 staining in bronchial epithelial cells, alveolar epithelium, alveolar macrophages, and smooth muscles of pulmonary vessels. Neutrophil depletion attenuated the interleukin-8 increase in the lung. Large Vt did not increase plasma interleukin-8 or tumor necrosis factor-&agr; in plasma and bronchoalveolar lavage fluid. No expression of p-selectin or intercellular adhesion molecule-1 was observed. ConclusionsCyclic overstretching of normal rabbit lungs with noninjurious large Vt produced neutrophil influx and interleukin-8 increase in bronchoalveolar lavage fluid. Production of pulmonary interleukin-8 by lung overstretch might require the interaction between resident lung cells and migrated neutrophils. This study suggests that large Vt ventilation potentiates the predisposed, subclinical lung injury, such as nosocomial pneumonia or aspiration of gastric contents.

Vascular endothelial growth factor in epithelial lining fluid of patients with acute respiratory distress syndrome

Background and objective:  Vascular endothelial growth factor (VEGF) is known to contribute to the development of pulmonary oedema, and has been suggested to have a protective role against lung injury. To determine the role of VEGF in acute lung injury (ALI) and ARDS, VEGF levels were measured in lung epithelial lining fluid (ELF) collected from patients with ALI/ARDS.

HMGB1 Accelerates Alveolar Epithelial Repair via an IL-1β- and αvβ6 Integrin-dependent Activation of TGF-β1

High mobility group box 1 (HMGB1) protein is a danger-signaling molecule, known to activate an inflammatory response via TLR4 and RAGE. HMGB1 can be either actively secreted or passively released from damaged alveolar epithelial cells. Previous studies have shown that IL-1β, a critical mediator acute lung injury in humans that is activated by HMGB1, enhances alveolar epithelial repair, although the mechanisms are not fully understood. Herein, we tested the hypothesis that HMGB1 released by wounded alveolar epithelial cells would increase primary rat and human alveolar type II cell monolayer wound repair via an IL-1β-dependent activation of TGF-β1. HMGB1 induced in primary cultures of rat alveolar epithelial cells results in the release of IL-1β that caused the activation of TGF-β1 via a p38 MAPK-, RhoA- and αvβ6 integrin-dependent mechanism. Furthermore, active TGF-β1 accelerated the wound closure of primary rat epithelial cell monolayers via a PI3 kinase α-dependent mechanism. In conclusion, this study demonstrates that HMGB1 released by wounded epithelial cell monolayers, accelerates wound closure in the distal lung epithelium via the IL-1β-mediated αvβ6-dependent activation of TGF-β1, and thus could play an important role in the resolution of acute lung injury by promoting repair of the injured alveolar epithelium.

Effects Of Tnf-α-converting Enzyme Inhibition On Acute Lung Injury Induced By Endotoxin In The Rat

We studied the effects of TNF-converting enzyme inhibition with Y-41654, which down-regulates the production of soluble TNF-&agr; (sTNF-&agr;), on acute lung injury induced by intratracheal administration of LPS. We first verified in vitro that pretreatment of isolated alveolar macrophages from Sprague-Dawley male rats with 20 &mgr;L of 0.1-mM Y-41654, decreased significantly (P < 0.05) the concentration of sTNF-&agr; in cell supernatants induced by 10 &mgr;g/mL of LPS. We then studied four groups of rats (each n = 10) including 1) a control group, 2) an LPS group (300 &mgr;g /kg, instilled intratracheally), 3) a Y-41654 group, and 4) a treatment group treated with Y-41654 after LPS instillation. Y-41654, 10 mg/kg in 0.7 mL of phosphate-buffered saline, was administered (i.v.), 15 min before and 0.5, 1.5, 2.5, and 3.5 h after saline or LPS instillation. The animals were observed for 4 h. In the animals treated with Y-41654, the concentrations of sTNF-&agr; and protein in bronchoalveolar lavage fluid, and the number of neutrophils in lung tissue and bronchoalveolar lavage fluid were significantly lower at 4 h than in the LPS group (P < 0.05). In conclusion, sTNF-&agr; plays an important role in the development of acute lung injury induced by intratracheal administration of LPS, in part modulating neutrophil kinetics.

Protective role of vascular endothelial growth factor in endotoxin-induced acute lung injury in mice.

BackgroundVascular endothelial growth factor (VEGF), a substance that stimulates new blood vessel formation, is an important survival factor for endothelial cells. Although overexpressed VEGF in the lung induces pulmonary edema with increased lung vascular permeability, the role of VEGF in the development of acute lung injury remains to be determined.MethodsTo evaluate the role of VEGF in the pathogenesis of acute lung injury, we first evaluated the effects of exogenous VEGF and VEGF blockade using monoclonal antibody on LPS-induced lung injury in mice. Using the lung specimens, we performed TUNEL staining to detect apoptotic cells and immunostaining to evaluate the expression of apoptosis-associated molecules, including caspase-3, Bax, apoptosis inducing factor (AIF), and cytochrome C. As a parameter of endothelial permeability, we measured the albumin transferred across human pulmonary artery endothelial cell (HPAEC) monolayers cultured on porous filters with various concentrations of VEGF. The effect of VEGF on apoptosis HPAECs was also examined by TUNEL staining and active caspase-3 immunoassay.ResultsExogenous VEGF significantly decreased LPS-induced extravascular albumin leakage and edema formation. Treatment with anti-VEGF antibody significantly enhanced lung edema formation and neutrophil emigration after intratracheal LPS administration, whereas extravascular albumin leakage was not significantly changed by VEGF blockade. In lung pathology, pretreatment with VEGF significantly decreased the numbers of TUNEL positive cells and those with positive immunostaining of the pro-apoptotic molecules examined. VEGF attenuated the increases in the permeability of the HPAEC monolayer and the apoptosis of HPAECs induced by TNF-α and LPS. In addition, VEGF significantly reduced the levels of TNF-α- and LPS-induced active caspase-3 in HPAEC lysates.ConclusionThese results suggest that VEGF suppresses the apoptosis induced by inflammatory stimuli and functions as a protective factor against acute lung injury.

Endothelin‐1 level in epithelial lining fluid of patients with acute respiratory distress syndrome

Background and objectives:  Endothelin‐1 (ET‐1), a potent vasoconstrictor peptide produced by endothelial cells, has been implicated in the dysfunction of various organs. To determine the role of ET‐1 in acute lung injury (ALI) and ARDS, ET‐1 levels were measured in epithelial lining fluid (ELF) and plasma obtained from patients with ALI/ARDS.

Effects of initial passage of endotoxin through the liver on the extent of acute lung injury in a rat model

ABSTRACT We hypothesized that the extent of acute lung injury (ALI) caused by lipopolysaccharide (LPS) is modified with its initial passage through the liver. We tested this hypothesis by administering LPS, 5 mg/kg, or saline to 120 male Wistar rats via the portal vein (PV) or the inferior vena cava (IVC) over 1 h. Four experimental groups of rats were administered saline into the PV, saline into the IVC, LPS into the PV (LPS-PV group), and LPS into the IVC (LPS-IVC group), respectively. At 15 and 30 min after onset of 51Chromium-LPS infusion, the &ggr; counts in the liver were higher in the LPS-PV group than that in the LPS-IVC group. The ratio of 125Iodine-albumin counts in lung tissue to that in plasma per unit of weight (as an assessment of pulmonary microvascular permeability) at 240 min after onset of LPS stimulation, the accumulation of polymorphonuclear cell (assessed by myeloperoxidase activity) and the concentration of tumor necrosis factor &agr; in the lung at 60 and 240 min after onset of LPS infusion, were higher in the LPS-IVC group than in the LPS-PV group. Significant differences in several factors indicative of inflammation and in the extent of LPS-induced ALI were observed after the onset of LPS infusion, depending on whether it was delivered via the PV or the IVC. These observations suggest that the entrapping of LPS during its initial passage through the hepatic circulation may attenuate LPS-induced ALI within 4 h of initiation of LPS stimulation.