Hiroshi Moriuchi

Activation of polymorphonuclear leukocytes in oleic acid-induced lung injury

AbstractObjective: Oleic acid (OA) can produce a lung injury similar to the adult respiratory distress syndrome (ARDS). Elastase and superoxides are thought to have an effect in ARDS. However, the effect that elastase and superoxide have in OA lung injury is unclear. To examine their involvement in OA lung injury, we tested the effects of methoxysuccinyl-alanyl-alanyl-prolyl-valyl chloromethyl ketone (MAAPVCK), an elastase inhibitor, and N-acetyl-L-cysteine (NAC), an active oxygen scavenger, on the increase in pulmonary vascular permeability caused by OA. We also examined whether OA stimulated elastase and/or superoxide release from polymorphonuclear leukocytes (PMNs). Design: Prospective trial. Setting: University laboratory. Interventions: (1) Guinea pigs were anesthetized. MAAPVCK (2.5 mg/kg) or NAC (150 mg/kg) was infused over OA (15 µl/kg) injection. Evans blue was used to measure vascular permeability. (2) PMNs were isolated from the blood of guinea pigs and rats. Elastase release was measured with MeO-Suc-Ala-Ala-Pro-Val-7-amino-4-methyl-coumarin. Superoxide production was measured by the ferricyto-chrome c reduction method. Measurements and results: OA caused pulmonary hemorrhage and an increase in vascular permeability. MAAPVCK and NAC significantly attenuated the increase in vascular permeability in distal bronchus and trachea, respectively. OA induced superoxide production from PMNs in guinea pigs, but elastase release from PMNs was not detected. Conclusions: These results suggest that elastase and superoxide are involved in OA lung injury.

Involvement of thromboxane A2 (TXA2) in the early stages of oleic acid-induced lung injury and the preventive effect of ozagrel, a TXA2 synthase inhibitor, in guinea-pigs

An intravenous injection of oleic acid into animals can produce a lung injury with hypoxaemia and pulmonary vascular hyper‐permeability. Although oleic acid lung injury is used as a model of acute respiratory distress syndrome (ARDS), the precise mechanisms of the lung injury are still unclear. We have investigated whether thromboxane A2 (TXA2) participated in the lung injury and have evaluated the efficacy of ozagrel, a TXA2 synthase inhibitor, on the lung injury in guinea‐pigs. Oleic acid injection increased the plasma level of TXB2, a stable metabolite of TXA2, and the time‐course of plasma TXB2 was similar to that of the decreased partial oxygen pressure of arterial blood (Pao2) induced with oleic acid. Ozagrel administered intravenously 30 min before oleic acid injection prevented the decrease in Pao2 and pulmonary vascular hyper‐permeability. It also prevented increases in lactate dehydrogenase activity, a measure of lung cell injury, TXB2 and its weight ratio to 6‐keto prostaglandin F1 α in bronchoalveolar lavage fluid. Although ozagrel administered simultaneously with oleic acid ameliorated the decrease in Pao2, post treatment showed little effect. We suggest that TXA2 participated in the oleic acid lung injury, as an “early phase” mediator, and rapidly‐acting TXA2 synthase inhibitors were effective in the prevention of acute lung injury.

The exacerbating roles of CCAAT/enhancer-binding protein homologous protein (CHOP) in the development of bleomycin-induced pulmonary fibrosis and the preventive effects of tauroursodeoxycholic acid (TUDCA) against pulmonary fibrosis in mice.

The purpose of this study was to evaluate the role of CCAAT/enhancer-binding protein homologous protein (CHOP), an important transcription factor that regulates the inflammatory reaction during the endoplasmic reticulum (ER) stress response, in the development of pulmonary fibrosis induced by bleomycin (BLM) in mice. An intratracheal injection of BLM transiently increased the expression of CHOP mRNA and protein in an early phase (days 1 and 3) in mice lungs. BLM-induced pulmonary fibrosis was significantly attenuated in Chop gene deficient (Chop KO) mice, compared with wild-type (WT) mice. Furthermore, the inflammatory reactions evaluated by protein concentration, the total number of leucocytes and neutrophils in the bronchoalveolar lavage fluid (BALF), the mRNA expression of interleukin 1b and caspase 11, and the apoptotic cell death were suppressed in Chop KO mice compared with those in WT mice. In addition, administration of tauroursodeoxycholic acid (TUDCA), a pharmacological agent that can inhibit CHOP expression, inhibited the BLM-induced pulmonary fibrosis and inflammation, and the increase in Chop mRNA expression in WT mice in a dose-dependent manner. These results suggest that the ER stress-induced transcription factor, CHOP, at least in part, plays an important role in the development of BLM-induced pulmonary fibrosis in mice, and that the inhibition of CHOP expression by a pharmacological agent, such as TUDCA, may be a promising strategy for the prevention of pulmonary fibrosis.

Pentoxifylline prevents a decrease in arterial oxygen tension in oleic acid-induced lung injury

OBJECTIVES a) To determine whether pentoxifylline has a preventive effect on the decrease in PaO2 that is caused by oleic acid, and whether pentoxifylline facilitates normalization of PaO2 from the decreased state. b) To examine whether pentoxifylline can attenuate an increase in pulmonary vascular permeability that is induced by oleic acid. DESIGN Prospective trial. SETTING University laboratory. SUBJECTS a) A total of 48 guinea pigs (700 to 1100 g) for blood gas analysis. b) A total of 28 guinea pigs (390 to 670 g) for measurement of pulmonary vascular permeability. INTERVENTIONS a) For blood gas analysis, the guinea pigs were mechanically ventilated. Oleic acid (15 microL/kg) was injected into the guinea pigs to decrease PaO2. Pentoxifylline (5 or 20 mg/kg) was administered 40 or 3 mins before oleic acid injection or 13 mins after oleic acid injection. b) For measurement of pulmonary vascular permeability, the guinea pigs were anesthetized with pentobarbital and catheterized via the external jugular vein for drug administration. Pentoxifylline (20 mg/kg) plus Evans blue (30 mg/kg) or theophylline (20 mg/kg) plus Evans blue (30 mg/kg) were administered at 40- and 1-min intervals before oleic acid (15 microL/kg) injection, respectively. Perfusion with saline was performed through the aorta 90 mins after the oleic acid injection. The airways were removed and separated into the trachea, the main bronchus, the proximal bronchus, and the distal bronchus. Evans blue was extracted from the airways with formamide for 18 hrs and measured. MEASUREMENTS AND MAIN RESULTS a) We measured PaO2, PaCO2, and pH, and recorded airway pressure and systemic blood pressure at 15, 10, and 5 mins before oleic acid injection and at 6, 10, 15, 35, 55, and 75 mins after oleic acid injection. Compared with the control groups, a decrease in PaO2 by oleic acid was significantly prevented when pentoxifylline (5 or 20 mg/kg) was administered 40 mins before oleic acid injection. However, a decrease in PaO2 by oleic acid was not significantly reduced when pentoxifylline was administered 3 mins before oleic acid injection. Pentoxifylline administered 13 mins after oleic acid injection did not affect the recovering course of PaO2 significantly. b) An increase in pulmonary vascular permeability by oleic acid was significantly attenuated by both pentoxifylline and theophylline. The effect of theophylline was significantly stronger than the effect of pentoxifylline in the main bronchi. The effect of theophylline was not significantly different from the effect of pentoxifylline in other areas. CONCLUSION Pentoxifylline is a noteworthy drug that could be a candidate as a therapy to help prevent hypoxemia in lung injuries that share a common mechanism with oleic acid-induced lung injury.

The effect of Maimendongtang on airway clearance and secretion

We investigated the effect of Maimendongtang on airway clearance and secretion in anaesthetized quails. The oral application of 1 g/kg of Maimendongtang significantly increased tracheal mucociliary transport velocity (MCTV), whereas 100 or 300 mg/kg of Maimendongtang failed to do so. Moreover, 300 mg/kg or 1 g/kg of Maimendongtang markedly attenuated human neutrophil elastase (HNE) or DNA‐induced decrease in MCTV although 100 mg/kg of Maimendongtang had little effect. Furthermore, we found that Maimendongtang significantly restored HNE‐induced increases in DNA, fucose and protein contents of airway surface fluid (ASF), whereas only Maimendongtang itself significantly decreased the protein content. These results indicate that Maimendongtang increases MCTV and the increase may be, at least in part, ascribed to the amelioration of ASF in the trachea. Copyright

Preclinical Investigation of the Topical Administration of Phenserine: Transdermal Flux, Cholinesterase Inhibition, and Cognitive Efficacy

Phenserine (PS) was designed as a selective acetylcholinesterase (AChE) inhibitor, with a tartrate form (PST) for oral administration in mild to moderate Alzheimers disease (AD). Recent phase 3 trials of PST in Europe indicate that any clinically relevant activity of PST may be limited by its duration of action. Like many oral drugs, bioavailability and plasma concentrations of PST are regulated by hepatic and gastrointestinal first-pass effects. To minimize the kinetic limitations of first-pass metabolism, transdermal formulations of PS and PST (ointment/patch) were developed and characterized in vitro and in vivo. Initial in vitro kinetic characterization of PS or PST formulations used a diffusion cell chamber and skin samples isolated from hairless mice. Liquid paraffin and fatty alcohol/propylene glycol (FAPG) were found to be suitable vehicles for ointment formulation. Addition of a penetration enhancer, 1-[2-(decylthio)ethyl]-azacyclopentane-2-one (HPE-101), improved stratum corneum permeability. Application of the optimal formulation of PS/HPE-101/FAPG to the shaved back of rats resulted in significantly lowered plasma and brain AChE activities and improved cognitive performance in animals with scopolamine-induced cognitive impairment. These results suggest that the transdermal application of AChE inhibitors may represent an effective therapeutic strategy for AD. Particular benefits over oral therapies might include avoiding first-pass metabolic effects and improved dosing compliance.

Protection afforded by a herbal medicine, Sho-seiryu-to (TJ-19), against oleic acid-induced acute lung injury in guinea-pigs.

Objectives The effect of a herbal medicine, Sho‐seiryu‐to (TJ‐19), on oleic acid‐induced lung injury, an animal model of acute respiratory distress syndrome or acute lung injury (ARDS/ALI), was examined.

Possible false-negative results on therapeutic drug monitoring of phenytoin using a particle enhanced turbidimetric inhibition immunoassay in a patient with a high level of IgM.

: In this report, the authors described the unusual case of a patient in whom the plasma phenytoin concentration was unexpectedly not detected on a particle-enhanced turbidimetric inhibition immunoassay (PETINIA) technique, a typical immunoassay for phenytoin. The plasma concentration was measured using PETINIA and high-performance liquid chromatography in a 69-year-old male patient treated with fosphenytoin intravenously at the standard dose for 7 days. Although the plasma concentration of phenytoin was below the limit of detection (<0.5 mcg/mL) on PETINIA after the administration of fosphenytoin, the trough plasma concentration was estimated to be between 5 and 10 mg/L on high-performance liquid chromatography. When the plasma concentrations of IgM and IgG were measured using an enzyme-linked immunosorbent assay, the plasma IgG level was within the reference range, whereas the plasma IgM level was 2-3 times higher than the upper limit of the reference range. We concluded that the PETINIA method yielded a possible false-negative result regarding the phenytoin level in this patient, perhaps because of some hindrance to the measurement process by IgM. This case suggests that false-negative results should be considered when therapeutic drug monitoring reveals abnormally low values using PETINIA and that it is necessary to evaluate the plasma IgM level.

Tranexamic acid attenuates oleic-acid-induced pulmonary extravasation

ObjectiveActivation of fibrinolysis is implicated in the development of vascular injury in certain lung injuries. It has yet to be reported that activation of plasmin is involved in extravasation caused by oleic acid (OA). We examined whether or not plasmin is involved in pulmonary extravasation by OA.DesignProspective trial.SettingUniversity laboratory.SubjectsA total of 78 guinea pigs (498.9±10.6 g).InterventionsEvans blue (EB) was administered to anesthetized guinea pigs. Subsequently four protocols were followed: (1) After 1 min, 60 μl/kg of OA was injected. Perfusion was performed 30, 60 or 90 min after OA injection to wash out intravascular EB. (2) After 1 min, 15, 30 or 60 μl/kg of OA was injected. (3) Tranexamic acid (TA) (2 g/kg) or saline was administered 30 min before OA (15 μl/kg) injection. (4) Diphenhydramine hydrochloride (2.9 mg/kg) or saline was administered 7 min before OA (15 μl/kg) injection.Measurement and resultsExcept in protocol 1, the chest cavity was opened 90 min after OA injection. Perfusion was then performed. Airway was separated into four parts from trachea to distal bronchus. EB was extracted from the tissues and measured. OA caused an extravasation throughout airways in a time-and dose-dependent manner. Extravasation was more conspicuous in peripheral tissues. TA significantly attenuated extravasation, while diphenhydramine hydrochloride did not.ConclusionsIt is suggested that plasmin, but not histamine, is involved in extravasation by OA. Inhibition of plasmin can be an effective strategy for treatment of this kind of lung injury.

Aminophylline, administered at usual doses for rodents in pharmacological studies, induces hippocampal neuronal cell injury under low tidal volume hypoxic conditions in guinea-pigs.

Objectives  To establish whether aminophylline, administered at usual doses for rodents in pharmacological studies, induces brain injury in systemic hypoxaemia in guinea‐pigs.