ELOVL6 deficiency aggravates allergic airway inflammation through the ceramide-S1P pathway in mice.

BACKGROUND: Elongation of very-long-chain fatty acids protein 6 (ELOVL6), an enzyme regulating elongation of saturated and monounsaturated fatty acids with C12 to C16 to those with C18, has been recently indicated to affect various immune and inflammatory responses; however, the precise process by which ELOVL6-related lipid dysregulation affects allergic airway inflammation is unclear. OBJECTIVES: This study sought to evaluate the biological roles of ELOVL6 in allergic airway responses and investigate whether regulating lipid composition in the airways could be an alternative treatment for asthma. METHODS: Expressions of ELOVL6 and other isoforms were examined in the airways of patients who are severely asthmatic and in mouse models of asthma. Wild-type and ELOVL6-deficient (Elovl6-/-) mice were analyzed for ovalbumin-induced, and also for house dust mite-induced, allergic airway inflammation by cell biological and biochemical approaches. RESULTS: ELOVL6 expression was downregulated in the bronchial epithelium of patients who are severely asthmatic compared with controls. In asthmatic mice, ELOVL6 deficiency led to enhanced airway inflammation in which lymphocyte egress from lymph nodes was increased, and both type 2 and non-type 2 immune responses were upregulated. Lipidomic profiling revealed that the levels of palmitic acid, ceramides, and sphingosine-1-phosphate were higher in the lungs of ovalbumin-immunized Elovl6-/- mice compared with those of wild-type mice, while the aggravated airway inflammation was ameliorated by treatment with fumonisin B1 or DL-threo-dihydrosphingosine, inhibitors of ceramide synthase and sphingosine kinase, respectively. CONCLUSIONS: This study illustrates a crucial role for ELOVL6 in controlling allergic airway inflammation via regulation of fatty acid composition and ceramide-sphingosine-1-phosphate biosynthesis and indicates that ELOVL6 may be a novel therapeutic target for asthma.

Has2 Regulates the Development of Ovalbumin-Induced Airway Remodeling and Steroid Insensitivity in Mice.

HAS2 is a member of the gene family encoding the hyaluronan synthase 2, which can generate high-molecular-weight hyaluronan (HMW-HA). Our previous study identified HAS2 as a candidate gene for increased susceptibility to adult asthma. However, whether HAS2 dysfunction affects airway remodeling and steroid insensitivity is still limited. Therefore, this study aimed to clarify the Has2 dysfunction, triggering severe airway remodeling and steroid insensitivity in a murine model of asthma. Has2 heterozygous-deficient (Has2+/-) mice and their wild-type littermates have been evaluated in a model of chronic ovalbumin (OVA) sensitization and challenge. Mice present a higher sensitivity to OVA and higher IL-17 release as well as eosinophilic infiltration. RNA sequencing demonstrated the downregulation of EIF2 signaling pathways, TGF-ß signaling pathways, and heat shock proteins with Th17 bias in Has2+/--OVA mice. The combined treatment with anti-IL-17A antibody and dexamethasone reduces steroid insensitivity in Has2+/--OVA mice. Has2 attenuation worsens eosinophilic airway inflammation, airway remodeling, and steroid insensitivity. These data highlight that HAS2 and HMW-HA are important for controlling intractable eosinophilic airway inflammation and remodeling and could potentially be exploited for their therapeutic benefits in patients with asthma.

Transcription Factor T-bet Attenuates the Development of Elastase-induced Emphysema in Mice.

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by peripheral airways inflammation and emphysema. Emerging evidence indicates a contribution of both innate and adaptive immune cells to the development of COPD. Transcription factor T-bet modulates the function of immune cells and therefore might be involved in the pathogenesis of COPD. To elucidate the role for T-bet in elastase-induced emphysema, pathological phenotypes were compared between wild-type and T-bet-/- mice. T-bet-/- mice demonstrated enhanced emphysema development on histological analyses, with higher values of mean linear intercept and dynamic compliance relative to wild-type mice. The number of neutrophils in BAL fluids, lung IL-6 and IL-17 expression, and the proportion of CD4+ T cells positive for IL-17 or retinoic acid receptor-related orphan receptor-γt were higher in T-bet-/- mice than in wild-type mice. Although T-bet downregulates cytokine expression in bone marrow-derived macrophages and MH-S cells, a murine alveolar cell line, depending on the surrounding environment, IL-6 expression in alveolar macrophages isolated from elastase-treated mice was not dependent on T-bet. Coculture of bone marrow-derived macrophages and CD4+ T cells revealed that T-bet regulation of IL-17 expression was dependent on CD4+ T cells. Neutralizing antibodies against IL-6R or IL-17 ameliorated the development of emphysema in T-bet-/- mice. In conclusion, we demonstrate that T-bet ameliorates elastase-induced emphysema formation by modulating the host immune response in the lungs.

Sulforaphane ameliorates steroid insensitivity through an Nrf2-dependent pathway in cigarette smoke-exposed asthmatic mice.

Oxidative stress induced by cigarette smoke and other environmental pollutants contributes to refractory asthma. To better understand the role of smoking in asthma, we investigated the effects of cigarette smoke on allergic airway responses in mice and examined expression of nuclear factor-E2-related factor-2 (Nrf2) and its downstream factors, because Nrf2 is known to play a pivotal role in antioxidant responses. OVA-sensitized and challenged BALB/c mice were exposed to cigarette smoke and then treated with dexamethasone, sulforaphane (an activator of Nrf2), or their combination. Upon exposure to cigarette smoke, Nrf2 and associated transcripts were upregulated in response to oxidative stress, and asthmatic responses were steroid resistant. In OVA-sensitized and challenged mice exposed to cigarette smoke and treated with sulforaphane, Nrf2-mediated antioxidant responses were upregulated to a greater extent, and steroid sensitivity of asthmatic responses was restored. Moreover, the expression and activity of histone deacetylase 2 (HDAC2), a key regulator of steroid responsiveness, was reduced in mice exposed to cigarette smoke, but restored by sulforaphane treatment. No effects of sulforaphane were observed in Nrf2-deficient mice. These findings indicate that cigarette smoke induces steroid unresponsiveness in asthmatic airways, and that sulforaphane restores steroid sensitivity via upregulation of Nrf2 and enhancement of HDAC2 expression and activity. Thus, Nrf2 may serve as a potential molecular target for cigarette smoke-related refractory asthma resistant to steroid therapy.

Paraneoplastic limbic encephalitis with late-onset magnetic resonance imaging findings: A case report.

Paraneoplastic limbic encephalitis (PLE), a paraneoplastic neurological syndrome (PNS), is a rare nervous system disorder that results from the indirect effects of tumors and is commonly associated with small-cell lung cancer (SCLC). Previous studies have reported that magnetic resonance imaging (MRI) may be useful for diagnosing LE. Temporal lobe abnormalities are observed using T2-weighted and fluid-attenuated inversion recovery sequences; however, such abnormalities are detected in only 60% of patients with PLE. The present study describes a case of PLE associated with SCLC, in which LE was observed using MRI 26 days after the first convulsive seizure. Although the serum and cerebrospinal fluid analyses for onconeural antibodies were negative, the findings of this case indicate that PLE should be considered in the differential diagnosis, and that repeated brain MRI may be more helpful for diagnosis, as the brain MRI findings may be normal during the early stages of PLE.

Limited value of transbronchial lung biopsy for diagnosing Mycobacterium avium complex lung disease.

BACKGROUND AND AIMS: It remains unclear whether transbronchial lung biopsy (TBLB) is useful for diagnosing Mycobacterium avium complex (MAC) lung disease. METHODS: Thirty-eight consecutive patients with MAC lung disease, who were evaluated with TBLB tissue culture between June 2006 and May 2010, were included. Bronchial washing (BW) and histopathological evaluation were performed in all patients. The positivity rates of BW and TBLB tissue culture, and typical histopathological findings for MAC disease were investigated. Furthermore, all patients were divided into two groups according to the presence of intrabronchial purulent or mucopurulent secretion and the clinical, bacteriological and pathological characteristics were compared between the two groups. RESULTS: The positive culture rates of BW and TBLB specimens for MAC were 100% (38 patients) and 28.9% (11 patients). BW materials were much more sensitive for culture positivity than TBLB specimens (P < 0.0001). Typical pathological findings for MAC disease were present in the TBLB specimens of only 11 patients (28.9%). Intrabronchial secretion was identified in 15 patients (39.5%, secretion-positive group) and absent in 23 patients (60.5%, secretion-negative group). Typical histopathological findings for MAC disease were more common in the secretion-positive group than in the secretion-negative group (53.3% vs 13.0%, P = 0.01), although the radiological classification and smear positivity of BW were not different between the two groups. CONCLUSION: TBLB for pathological and bacterial investigations would provide only a limited value for MAC diagnosis. Moreover, the presence of intrabronchial secretion may be an important manifestation of ongoing airway damage, which would require early treatment.

Landiolol hydrochloride ameliorates acute lung injury in a rat model of early sepsis through the suppression of elevated levels of pulmonary endothelin-1.

Among the dysfunctions and pathologies associated with sepsis, the underlying molecular mechanisms of sepsis-induced acute lung injury (ALI) are poorly understood. Endothelin (ET)-1, a potent vasoconstrictor and pro-inflammatory peptide, is known to be involved in the pathogenesis of ALI in a rat model of sepsis. Here, we investigated whether landiolol hydrochloride, an ultra-short-acting ß-blocker, plays a crucial role in ameliorating and attenuating LPS-induced ALI through modulation of the ET-1 system. Male Wistar rats at 8weeks of age were administered with either saline or lipopolysaccharide (LPS) for three hours (3h) and some of the LPS-administered rats were continuously treated with landiolol for 3h. ALI was induced by LPS, including levels of both circulatory and pulmonary TNF-α and IL-6 but [PaO2] was significantly decreased. LPS also induced a significant increase in levels of pulmonary ET-1 and ET-A receptor, but levels of ET-B receptor, which has vasodilating effects, were remarkably diminished. Further, LPS administration upregulated the pulmonary expression of HIF-1α. Finally, the treatment of LPS-administered rats with landiolol for 3h ameliorated and prevented ALI, normalized the altered levels of pulmonary ET-1 and ET-A receptors. Landiolol also induced significant down-regulation of ET-B receptor in lung tissues in the early hours (phase) of sepsis. However, Landiolol treatment had no effect on the up-regulated inflammatory mediators (TNF-α, IL-6) in both plasma and lung tissues during sepsis, and expression of pulmonary HIF-1α also remained unchanged after landiolol treatment. Collectively, these data led us to conclude that landiolol may ameliorate sepsis-induced ALI via the pulmonary ET system.

[MYCOBACTERIUM ABSCESSUS PULMONARY DISEASE: IMPORTANT PATHOGEN INVOLVED IN MICROBIAL SUBSTITUTION DURING THE TREATMENT OF NON-ABSCESSUS MYCOBACTERIAL DISEASE].

INTRODUCTION: Mycobacterium abscessus pulmonary disease is common in patients with bronchiectasis. However, the underlying disease that is more likely to be present in patients with M. abscessus pulmonary disease remains poorly understood. METHOD: From 2001 through 2010, all patients, whose sputum or bronchoscopic lavage cultures yielded M. abscessus, were included in the study. RESULTS: Among the 11 patients included (male/female: 4/7), 4 male patients had a history of smoking. All 11 patients presented with bronchiectasis on computed tomography before the detection of M. abscessus, and most patients demonstrated nodular bronchiectasis on chest computed tomography. Six patients (54.5%) developed M. abscessus pulmonary disease during treatment for non-abscessus non-tuberculous mycobacterial disease: M. avium complex pulmonary disease in 5 and M. kansasii infection in 1. Although laboratory examination yielded negative findings for non-abscessus mycobacterium when M. abscessus was detected, radiographic deterioration was observed in 4 of 6 patients. Five patients received drug therapy, 3 of whom were treated with multi-drug therapy including clarithromycin, ethambutol, and rifampicin, and the remaining 2 patients received low-dose macrolide therapy. However, M. abscessus was detected consistently in all patients, and deteriorated chest CT findings were observed in 4. Among the remaining 6 patients untreated with drugs, sputum cultures yielded. M. abscessus with radiographic deterioration in 4 patients. CONCLUSION: Our results indicated that M. abscessus infection developed during the treatment for non-abscessus mycobacterial disease, which was mainly due to M. avium complex pulmonary disease in most patients. M. abscessus infection thus occurred via microbial substitution. This phenomenon should be considered an important issue during the treatment for non-abscessus mycobacterial disease, which requires long-term medication.

Lung cancer with spontaneous regression of primary and metastatic sites: A case report.

Partial or complete spontaneous cancer regression is a rare phenomenon, particularly in patients with lung cancer. This is the case report of a patient with lung cancer who exhibited spontaneous regression of the primary as well as metastatic lesions, without receiving any treatment. Spontaneous regression commenced within a week of obtaining pathological specimens by transbronchial and percutaneous biopsies from the primary lesion and metastatic lymph nodes of the left side of the neck. The reason for this phenomenon is unknown; however, we hypothesized that there may be an immunological association between the stimulus of the biopsies and the spontaneous regression. This patient should be closely followed up to monitor the clinical course of this unusual case.

Central nervous system manifestations of tuberculosis-associated immune reconstitution inflammatory syndrome during adalimumab therapy: a case report and review of the literature.

A 64-year-old neurologically asymptomatic woman with rheumatoid arthritis who was treated with the tumor necrosis factor (TNF)-α antagonist adalimumab developed disseminated tuberculosis (TB). After receiving anti-TB therapy and discontinuing adalimumab, she exhibited paradoxical worsening due to immune reconstitution inflammatory syndrome (IRIS) with the appearance of meningitis and brain tuberculomas. This case indicates that continuing anti-TNF therapy may be necessary to prevent IRIS in patients who develop TB, particularly disseminated TB, during the course of anti-TNF therapy. In addition, careful screening for central nervous system (CNS) TB should be performed prior to the initiation of therapy, as even neurologically asymptomatic patients can develop CNS manifestations of IRIS.

Clinical experience with pirfenidone in five patients with scleroderma-related interstitial lung disease.

Interstitial lung disease is the most common complication and cause of death among patients with scleroderma. Scleroderma-related interstitial lung disease has usually been treated with cyclophosphamide; however, its effect was evaluated to be modest and long-term administration of this drug is associated with adverse effects. Herein, we report our clinical experience of administering pirfenidone, which is an antifibrotic agent, in five patients with scleroderma-related interstitial lung disease. All patients demonstrated an increase in vital capacity.

Benign myoepithelioma in the intrathoracic trachea.

A 67-year-old woman who was followed as a patient with bronchial asthma for 1.5 years visited our hospital with progressive dyspnea. Although the chest radiography findings were normal, a chest computed tomography scan revealed a mass obliterating the intrathoracic tracheal lumen. The patient's symptoms disappeared immediately after tumor excision, and no recurrence was observed during a 1.5-year follow-up period. Microscopically, the tumor was composed of densely packed polygonal-, oval- and spindle-shaped cells that were positive for pan-cytokeratin, α-smooth muscle actin and p63. These pathological findings confirmed the diagnosis of benign myoepithelioma. Chest physicians should recognize that benign myoepithelioma can develop in the trachea, although it is very rare.

Spontaneous coronary artery dissection in a patient with bacterial meningitis.

A 40-year-old man was admitted to our hospital because of the acute onset of fever and headache, which were attributed to bacterial meningitis. Antibiotic treatment was initiated and his condition gradually improved. On day 5 after admission, immediately after masturbation, he developed abrupt onset of severe chest pain and cold sweat and the ECG suggested acute anterior myocardial infarction. Immediate coronary angiography revealed spontaneous dissection of the left anterior descending artery. After conservative management, his cardiac function improved. Acute coronary syndrome may be rarely caused by spontaneous coronary artery dissection. Sepsis was considered as a probable trigger for spontaneous coronary artery dissection, possibly through vascular damage from increased nitric oxide and sympathetic nervous over-activation.

Prevalence of underlying lung disease in smokers with epidermal growth factor receptor-mutant lung cancer.

The prevalence of underlying lung diseases, such as emphysema and interstitial lung disease in smokers with epidermal growth factor receptor (EGFR)-mutant lung cancer remains unclear. This study aimed to clarify the correlation between the EGFR mutation status and the prevalence of underlying lung disease in smokers with lung cancer. A total of 88 consecutive smokers with non-small cell or non-squamous cell lung cancer who underwent surgical resection at our hospital from January 2007 through December 2010 were included in this study. The patients were divided into two groups on the basis of the EGFR mutation status: the mutation-positive group (n=19) and the wild-type group (n=69). The results of radiographic assessment via computed tomography (CT) and pulmonary function analysis were compared between the two groups. In the radiological evaluation, CT images at three levels were evaluated by two reviewers. Radiographic assessment revealed that the mutation-positive group tended to have milder emphysematous changes and a lower prevalence of interstitial changes compared with the wild-type group (P=0.13, 0.06). When the analysis was limited to the ipsilateral lung at the nearest CT level to the tumor, emphysematous changes were found to be less common in the mutation-positive group (P=0.02). The prevalence of the emphysematous and/or interstitial changes in the ipsilateral lung at the nearest CT level to the tumor was lower in the mutation-positive group compared to the wild-type group (P=0.005). In the pulmonary function test, the results were comparable between the two groups. In conclusion, according to our results, EGFR-mutant lung cancer was commonly observed in the areas where emphysematous and interstitial changes were absent. EGFR-mutant lung cancer may develop in radiographically normal areas of the lungs, even in smokers. It would be of importance to evaluate the EGFR mutation status in patients with no emphysematous or interstitial changes in the ipsilateral lung near the tumor, regardless of their smoking history. These results should be confirmed in a future prospective study.

Two cases of tuberculosis with multiple drug hypersensitivity after drug-induced hypersensitivity syndrome.

Here, we report 2 cases of drug-induced hypersensitivity syndrome (DIHS) caused by salazosulfapyridine and allopurinol during tuberculosis treatment. Both patients also developed multiple drug hypersensitivity (MDH) to several antituberculosis drugs that were used at around the period of DIHS onset, and thus, the treatment could not be successfully completed. Our cases show that MDH can easily occur after development of DIHS. Considering that treatment for tuberculosis requires long-term management with several drugs, it is important to refrain from administering drugs that can cause DIHS during tuberculosis treatment.