Tetsuo Yasutake

Inflammation provoked by Mycoplasma pneumoniae extract: implications for combination treatment with clarithromycin and dexamethasone

Recently, combination treatment with a macrolide and a steroid for Mycoplasma pneumoniae (Mp) pneumonia has been reported to be effective. Thus, the effect of this combination on a mouse model of lung inflammation associated with Mp extract (the LIMEX mouse) was studied. Interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) were induced in Mp extract-treated RAW264.7 cells, and this induction was inhibited by dexamethasone, parthenolide, SB203580 or LY294002. This suggested that Mp extract activates nuclear factor κB-, p38- and PI-3K-linked pro-inflammatory signals. The LIMEX mice were then either treated with or without clarithromycin and/or dexamethasone. Clarithromycin administration enhanced the production of IL-6, TNF-α, macrophage inflammatory protein-1α, monocyte chemotactic protein-1 and RANTES, while their production was perfectly suppressed by the combination of clarithromycin and dexamethasone. IL-17, IL-23, keratinocyte-derived chemokine (KC) and interferon-γ levels were not affected by clarithromycin treatment, but they were significantly suppressed by the combination of dexamethasone and clarithromycin. Collectively, some components of Mp extract provoked an inflammatory reaction in the RAW 264.7 cell line and LIMEX mice. Whereas the lung reaction in LIMEX mice was further exacerbated by clarithromycin treatment, it was resolved by the combinational treatment with clarithromycin and dexamethasone.

Erythromycin prevents the pulmonary inflammation induced by exposure to cigarette smoke

The effect of erythromycin on the inflammation caused by exposure to cigarette smoke was investigated in this study. Mice were exposed either to cigarette smoke or to environmental air (control), and some mice exposed to cigarette smoke were treated with oral erythromycin (100 mg/kg/day for 8 days). Pulmonary inflammation was assessed by determining the cellular content of bronchoalveolar lavage (BAL) fluid. The messenger RNA (mRNA) levels of various mediators, including keratinocyte-derived chemokine (KC), macrophage inflammatory protein (MIP)-2, surfactant protein (SP)-D, granulocyte macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor (TNF)-α, interleukin (IL)-6 in lung tissue were determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. The exposure to cigarette smoke increased significantly the numbers of neutrophils (P = 0.029), macrophages (P = 0.029), and lymphocytes (P = 0.029) recovered in BAL fluid. Moreover, mRNA levels of KC (P = 0.029), MIP-2 (P = 0.029), SP-D (P = 0.029), and GM-CSF (P = 0.057) in the lung tissue were higher in mice exposed to cigarette smoke than in mice exposed to environmental air. In the erythromycin-treated mice that were exposed also to cigarette smoke, both neutrophil and lymphocyte counts were significantly lower in the BAL fluid than those in the vehicle-treated mice (P = 0.029). Erythromycin-treated mice exposed to cigarette smoke showed a trend of lower mRNA levels of KC and TNF-α in the lung tissue than those in the vehicle-treated mice, although the statistical significance was not achieved (P = 0.057). Our data demonstrated that erythromycin prevented lung inflammation induced by cigarette smoke, in parallel to the reduced mRNA levels of KC and TNF-α.

Kinetics of c-reactive protein (CRP) and serum amyloid A protein (SAA) in patients with community-acquired pneumonia (CAP), as presented with biologic half-life times.

Context: In management of community-acquired pneumonia (CAP), excellent biomarkers for inflammation would be helpful in our practice. Objectives: Kinetics of c-reactive protein (CRP) and serum amyloid A (SAA) was characterized, using their biologic half-life times. Materials and methods: Time course of CRP and SAA levels in the successfully treated 36 CAP patients were investigated and their half-life times were determined and compared. Results & Discussions: SAA and CRP declined in an exponential mean and the biologic half-life times of SAA levels was 34.9 ± 28.7 h, significantly shorter than that of CRP, 46.4 ± 21.7 h (p = 0.0014). Conclusion: The kinetic evidence, presented as biologic half-life times of CRP and SAA, helps us make a clinical assessment of CAP patients.

Risk factors for bacteraemia attributable to Pseudomonas aeruginosa resistant to imipenem, levofloxacin, or gentamicin.

We studied the risk factors associated with resistance to imipenem, levofloxacin and gentamicin in Pseudomonas aeruginosa isolated from blood cultures of 175 patients in a hospital in Japan. Imipenem resistance was associated with transfer from another hospital, and receiving antifungal medication. Gentamicin resistance was associated with previous administration of a penicillin. No specific risk factors were associated with levofloxacin resistance.

Pathological Evidence of Rhabdomyolysis-induced Acute Tubulointerstitial Nephritis Accompanying Legionella pneumophila Pneumonia

A case of Legionella pneumophila pneumonia with rhabdomyolysis-induced acute tubulointerstitial nephritis (ATIN) and prolonged renal dysfunction is presented. The patient was a 54-year-old man, admitted with high-grade fever, ataxia and muscle dysfunction; chest roentgenogram showed multilobular infiltrations. L pneumophila was detected in his sputum and urine, by PCR and by culture, and L pneumophila pneumonia was diagnosed. Despite antimicrobial treatment, he developed renal failure and rhabdomyolysis. Renal biopsy showed the presence of myoglobin casts that occluded the distal tubuli and tubulointerstitial nephritis, leading to the diagnosis of rhabdomyolysis-induced ATIN. Renal function subsequently normalised, and he was discharged. This is believed to be the first pathological evidence of involvement of rhabdomyolysis in legionellosis-associated ATIN.

Interleukin-10 modulates pulmonary neutrophilic inflammation induced by cigarette smoke exposure.

ABSTRACT Aim of the Study: Interleukin (IL)-10 is an anti-inflammatory cytokine, but its role in cigarette smoke (CS)-induced inflammation and chronic obstructive pulmonary disease (COPD) has not been fully elucidated. The purpose of this study was to investigate the effect of IL-10 deficiency on CS-induced pulmonary inflammation in mice in vivo and in vitro. Materials and Methods: IL-10-deficient and wild-type control mice with a C57BL6/J genetic background were exposed to CS, and inflammatory cells in bronchoalveolar lavage fluid (BALF) and mRNA of cytokines in lung were evaluated with enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR). Results: During 12 days of daily CS exposure to wild-type mice, neutrophil counts in BAL fluid and tumor necrosis factor (TNF)-α mRNA expression were increased, peaked at day 8, and then declined on day 12 when the level of IL-10 reached its peak. In IL-10-deficient mice, neutrophil recruitment and TNF-α mRNA levels induced by CS exposure were significantly greater than those in wild-type mice. Keratinocyte-derived chemokine (KC; murine ortholog of human CXCL8) and granulocyte macrophage colony-stimulating factor (GM-CSF) mRNA levels or matrix metalloproteinase(MMP)-9 protein levels were not correlated with neutrophil count. Conclusions: IL-10 had a modulatory effect on CS-induced pulmonary neutrophilic inflammation and TNF-α expression in mice in vivo and therefore appears to be an important endogenous suppressor of airway neutrophilic inflammation.

Anacardic acid, a histone acetyltransferase inhibitor, modulates LPS-induced IL-8 expression in a human alveolar epithelial cell line A549

Objective and design: The histone acetylation processes, which are believed to play a critical role in the regulation of many inflammatory genes, are reversible and regulated by histone acetyltransferases (HATs), which promote acetylation, and histone deacetylases (HDACs), which promote deacetylation. We studied the effects of lipopolysaccharide (LPS) on histone acetylation and its role in the regulation of interleukin (IL)-8 expression. Material: A human alveolar epithelial cell line A549 was used in vitro. Methods: Histone H4 acetylation at the IL-8 promoter region was assessed by a chromatin immunoprecipitation (ChIP) assay. The expression and production of IL-8 were evaluated by quantitative polymerase chain reaction and specific immunoassay. Effects of a HDAC inhibitor, trichostatin A (TSA), and a HAT inhibitor, anacardic acid, were assessed. Results: Escherichia coli-derived LPS showed a dose- and time-dependent stimulatory effect on IL-8 protein production and mRNA expression in A549 cells in vitro. LPS showed a significant stimulatory effect on histone H4 acetylation at the IL-8 promoter region by ChIP assay. Pretreatment with TSA showed a dose-dependent stimulatory effect on IL-8 release from A549 cells as compared to LPS alone. Conversely, pretreatment with anacardic acid inhibited IL-8 production and expression in A549 cells. Conclusion: These data suggest that LPS-mediated proinflammatory responses in the lungs might be modulated via changing chromatin remodeling by HAT inhibition.