Saeko Takahashi

Reversal of elastase-induced pulmonary emphysema and promotion of alveolar epithelial cell proliferation by simvastatin in mice

Besides lowering cholesterol, statins exert multiple effects, such as anti-inflammatory activity and improvement of endothelial cell function. We examined whether simvastatin (SS) protects against the development of elastase-induced pulmonary emphysema in mice by using mean linear intercepts of alveoli (Lm) as a morphometric parameter of emphysema. After injection of intratracheal elastase on day 0, C57BL/6 mice were treated daily with SS (SS+ group) or PBS (SS- group) for 2 wk. A 21% decrease in Lm on day 7 was observed in the SS+ group vs. the SS- group. Anti-inflammatory effects of SS were observed as a decrease in percentage of neutrophils up to day 3, and in hydroxyproline concentration on day 3, in bronchoalveolar lavage fluid (BALF). SS also increased the number of proliferating cell nuclear antigen (PCNA)-positive alveolar epithelial cells between days 3 and 14. To confirm the role of statins in promoting proliferation of alveolar cells, mice were treated with SS (SS+) vs. PBS (SS-) for 12 days, starting 3 wk after elastase administration. After SS treatment, Lm decreased by 52% and PCNA-positive alveolar epithelial cells increased compared with the SS- group. Concentrations of vascular endothelial growth factor in BALF and endothelial nitric oxide synthase protein expression in pulmonary vessels tended to be higher in the SS+ group vs. the SS- group in this protocol. In conclusion, SS inhibited the development of elastase-induced pulmonary emphysema in mice. This therapeutic effect was due not only to anti-inflammation but also to the promotion of alveolar epithelial cell regeneration, partly mediated by restoring endothelial cell functions.

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).

Limitation of cigarette consumption by CYP2A6*4, *7 and *9 polymorphisms

The whole gene deletion CYP2A6*4, the defect of the main nicotine oxidase, contributes to limiting lifelong and daily cigarette consumption. However, the effects on smoking habits of CYP2A6*7 and *9, two major functional polymorphisms common in Asian populations, have not been reported. The present study examined the relationship between polymorphisms *4, *7 and *9 with the smoking habits of 200 Japanese smokers who visited the Keio University Hospital (Tokyo, Japan). The allele frequencies of *1 (wild type), *4, *7 and *9 were 52, 17, 11 and 20%, respectively. When the three polymorphisms were considered simultaneously, the percentages of homozygous wild type, heterozygote, and homozygous mutants and compound heterozygotes were 26.0, 52.5 and 21.5%, respectively. Homozygous mutants and compound heterozygotes (n = 43) smoked fewer cigarettes daily than heterozygotes (n = 105) and homozygous wild-type individuals (n = 52). Smokers with *7/*7, *9/*9 or *7/*9 had lower daily cigarette consumption than smokers with *1/*1. In conclusion, polymorphisms *4, *7 and *9 of CYP2A6 were detected in approximately three out of four Japanese smokers, and their daily cigarette consumption was genetically modulated by these functional polymorphisms.

F-18 FDG PET imaging in a patient with granulocyte colony stimulating factor producing pulmonary pleomorphic carcinoma.

We studied the diffusely increased fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) in the vertebrae of a 74-year-old man with granulocyte colony stimulating factor (G-CSF) producing pulmonary pleomorphic carcinoma. The PET findings were due to bone marrow hyperplasia induced by G-CSF and indicate that we should be careful in differentiating these findings from bone metastases and complications with hematological disease. The Tc-99m HMDP bone scan was normal. PET image in another patient with lung cancer after treatment by rhG-CSF resembles that of the described case. PET imaging in a patient with G-CSF producing carcinoma is probably rare.

Polymorphism of LRP5 gene and emphysema severity are associated with osteoporosis in Japanese patients with or at risk for COPD

Osteoporosis is an important systemic comorbidity of chronic obstructive pulmonary disease (COPD). However, neither its mechanisms nor its risk factors have been fully elucidated. With regard to genetic factors, low‐density lipoprotein receptor‐related protein 5 (LRP5) A1330V is known to be associated with osteoporosis in the general population, but the influence of this polymorphism in COPD is unknown. The aim of this study was to investigate the potential risk factors of COPD‐related bone loss and fracture.

Evaluation of cigarette smoke-induced emphysema in mice using quantitative micro-computed tomography

Chronic cigarette smoke (CS) exposure provokes variable changes in the lungs, and emphysema is an important feature of chronic obstructive pulmonary disease. The usefulness of micro-computed tomography (CT) to assess emphysema in different mouse models has been investigated, but few studies evaluated the dynamic structural changes in a CS-induced emphysema mouse model. A novel micro-CT technique with respiratory and cardiac gating has resulted in high-quality images that enable processing for further quantitative and qualitative analyses. Adult female C57BL/6J mice were repeatedly exposed to mainstream CS, and micro-CT scans were performed at 0, 4, 12, and 20 wk. Emphysema was also histologically quantified at each time point. Air-exposed mice and mice treated with intratracheal elastase served as controls and comparisons, respectively. End-expiratory lung volume, corresponding to functional residual volume, was defined as the calculated volume at the phase of end-expiration, and it evaluated air trapping. The end-expiratory lung volumes of CS-exposed mice were significantly larger than those of air controls at 12 and 20 wk, which was in line with alveolar enlargement and destruction by histological quantification. However, CS exposure neither increased low attenuation volume nor decreased the average lung CT value at any time point, unlike the elastase-instilled emphysema model. CS-exposed mice had rather higher average lung CT values at 4 and 12 wk. This is the first study characterizing a CS-induced emphysema model on micro-CT over time in mice. Moreover, these findings extend our understanding of the distinct pathophysiology of CS-induced emphysema in mice.

Annexin V decreases PS-mediated macrophage efferocytosis and deteriorates elastase-induced pulmonary emphysema in mice

Efferocytosis is believed to be a key regulator for lung inflammation in chronic obstructive pulmonary disease. In this study we pharmacologically inhibited efferocytosis with annexin V and attempted to determine its impact on the progression of pulmonary emphysema in mouse. We first demonstrated in vitro and in vivo efferocytosis experiments using annexin V, an inhibitor for phosphatidylserine-mediated efferocytosis. We then inhibited efferocytosis in porcine pancreatic elastase (PPE)-treated mice. PPE-treated mice were instilled annexin V intranasally starting from day 8 until day 20. Mean linear intercept (Lm) was measured, and cell apoptosis was assessed in lung specimen obtained on day 21. Cell profile, apoptosis, and mRNA expression of matrix metalloproteinases (MMPs) and growth factors were evaluated in bronchoalveolar lavage (BAL) cells on day 15. Annexin V attenuated macrophage efferocytosis both in vitro and in vivo. PPE-treated mice had a significant higher Lm, and annexin V further increased that by 32%. More number of macrophages was found in BAL fluid in this group. Interestingly, cell apoptosis was not increased by annexin V treatment both in lung specimens and BAL fluid, but macrophages from mice treated with both PPE and annexin V expressed higher MMP-2 mRNA levels and had a trend for higher MMP-12 mRNA expression. mRNA expression of keratinocyte growth factor tended to be downregulated. We showed that inhibited efferocytosis with annexin V worsened elastase-induced pulmonary emphysema in mice, which was, at least partly, attributed to a lack of phenotypic change in macrophages toward anti-inflammatory one.

The reasons for triple therapy in stable COPD patients in Japanese clinical practice

Background Triple combination therapy involving long-acting muscarinic antagonists long-acting β2 agonists, and inhaled corticosteroids has recently become an option for maintenance treatment of COPD. Some add-on clinical trials have reported the benefits of these combinations. However, the process to step up to triple therapy varies for individual cases. Methods Keio University and affiliated hospitals conducted an observational COPD cohort study, recruiting patients diagnosed as having COPD by pulmonary physicians and those referred for investigation of possible COPD. Their prescription history and clinical course were retrospectively analyzed based on the physicians’ medical records and patient questionnaires. This study was registered with UMIN (UMIN000003470, April 10, 2010). Results A total of 95 of the 445 COPD patients (21%) were treated with inhaled corticosteroids/long-acting β2 agonists/long-acting muscarinic antagonists as maintenance therapy, including 12 in COPD Grade I, 31 in Grade II, 38 in Grade III, and 14 in Grade IV, based on the Global Initiative for Chronic Obstructive Lung Disease spirometric grading. For more than half of the patients on triple therapy, the treatment had been intensified due to unsatisfactory improvement of symptoms, and 32% were treated with triple therapy due to comorbid asthma. In contrast, there were COPD patients whose therapy was maintained after starting with triple therapy because of their serious conditions or concurrent exacerbation at diagnosis (8%). Conclusion Triple therapy was often prescribed in the real-life management of COPD, even in patients whose airflow limitation was not severe. To better control symptoms was the major reason for choosing triple therapy, regardless of the severity of COPD, in Japan.

Common functional polymorphisms in the cathepsin S promoter in Japanese subjects: Possible contribution to pulmonary emphysema

Background and objective:  Cathepsin S is involved in the pathogenesis of COPD in murine models overexpressing interferon (IFN)‐γ and IL‐13. It is widely accepted that genetic factors partly influence susceptibility to COPD; however, the association of genetic polymorphisms in the cathepsin S gene with COPD has not been reported previously. In this study, functional polymorphisms in the 5′‐flanking region of the human cathepsin S gene were identified and their association with COPD phenotypes was investigated.

Pneumococcal Infection Aggravates Elastase-Induced Emphysema via Matrix Metalloproteinase 12 Overexpression

BACKGROUND Acute exacerbation of chronic obstructive pulmonary disease (COPD)--typically caused by bacterial or viral infection--is associated with poor prognosis and emphysema progression through unknown mechanisms. We aimed to elucidate the mechanisms responsible for the poor prognosis and emphysema progression associated with COPD exacerbation. METHODS We established a mouse model mimicking acute human COPD exacerbation, wherein mice with elastase-induced emphysema were intranasally infected with Streptococcus pneumoniae. RESULTS In mice with elastase-induced emphysema, infection with S. pneumoniae resulted in increased mortality, an increased number of inflammatory cells in bronchoalveolar lavage fluid (BALF), and increased matrix metalloproteinase 12 (MMP-12) production in the lungs, as well as enhanced emphysema progression. The increased MMP-12 production was mostly due to alveolar type II cells, alveolar macrophages, and lymphocytes that aggregated around vessels and bronchioles. Dexamethasone treatment suppressed the mortality rate and number of inflammatory cells in BALF but not emphysema progression, possibly owing to the failure of MMP-12 suppression in the lungs, whereas treatment with the MMP inhibitor ONO-4817 dramatically suppressed both mortality rate and emphysema progression. CONCLUSIONS These results suggest that MMP-12 production during COPD exacerbation results in increased mortality and emphysema progression. Our study identifies MMP-12 as a target to prevent further aggravation of COPD.