Masayuki Hanaoka

Genetics and genomics of pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a rare disorder that may be hereditable (HPAH), idiopathic (IPAH), or associated with either drug-toxin exposures or other medical conditions. Familial cases have long been recognized and are usually due to mutations in the bone morphogenetic protein receptor type 2 gene (BMPR2), or, much less commonly, 2 other members of the transforming growth factor-beta superfamily, activin-like kinase-type 1 (ALK1) and endoglin (ENG), which are associated with hereditary hemorrhagic telangiectasia. In addition, approximately 20% of patients with IPAH carry mutations in BMPR2. We provide a summary of BMPR2 mutations associated with HPAH, most of which are unique to each family and are presumed to result in loss of function. We review the finding of missense variants and variants of unknown significance in BMPR2 in IPAH/HPAH, fenfluramine exposure, and PAH associated with congenital heart disease. Clinical testing for BMPR2 mutations is available and may be offered to HPAH and IPAH patients but should be preceded by genetic counseling, since lifetime penetrance is only 10% to 20%, and there are currently no known effective preventative measures. Identification of a familial mutation can be valuable in reproductive planning and identifying family members who are not mutation carriers and thus will not require lifelong surveillance. With advances in genomic technology and with international collaborative efforts, genome-wide association studies will be conducted to identify additional genes for HPAH, genetic modifiers for BMPR2 penetrance and genetic susceptibility to IPAH. In addition, collaborative studies of BMPR2 mutation carriers should enable identification of environmental modifiers, biomarkers for disease development and progression, and surrogate markers for efficacy end points in clinical drug development, thereby providing an invaluable resource for trials of PAH prevention.

Airway inflammation during stable and acutely exacerbated chronic obstructive pulmonary disease

The aim of this study was to clarify the mechanism of increased airway inflammation during an acute exacerbation. A total of 68 chronic obstructive pulmonary disease patients in a stable phase were enrolled and followed-up for 2–3 yrs. Inflammatory cells were analysed, and interleukin (IL)-8, neutrophil elastase, eotaxin, tryptase and RANTES (regulated on activation, normal T-cell expressed and secreted) were measured in sputum, both in a stable phase and during acute exacerbation. Out of 68 patients, 30 (unstable group) developed an acute exacerbation and expectorated adequate sputum during exacerbation. Thirty-two patients (stable group) did not develop any exacerbation for 2–3 yrs. The number of neutrophils, lymphocytes and eosinophils, and the levels of IL-8, eosinophil cationic protein (ECP), eotaxin and tryptase in sputum obtained from patients in both groups during the stable phase were significantly higher than those from healthy nonsmokers. There were no significant differences in cell analysis and biomarkers between the two groups, but patients in the unstable group showed more severe airflow limitation. In the unstable group, total cells, lymphocytes, neutrophils and eosinophils, and IL-8, neutrophil elastase, ECP and RANTES levels were significantly increased during an exacerbation from values in a stable phase. These findings suggest that exacerbation of chronic obstructive pulmonary disease may associate with additional increases in airway inflammation mediated by neutrophils, lymphocytes, eosinophils, interleukin-8 and RANTES.

Positive Association of the Endothelial Nitric Oxide Synthase Gene Polymorphisms With High-Altitude Pulmonary Edema

Background—A defect of nitric oxide (NO) synthesis in the lung of high-altitude pulmonary edema (HAPE) has been suggested to contribute to its exaggerated pulmonary hypertension. Several polymorphisms have been identified in the gene encoding endothelial nitric oxide synthase (eNOS), which is a key enzyme responsible for NO synthesis, some of which were reported to be associated with vascular disorders. Methods and Results—We studied 41 HAPE-susceptible subjects (HAPE-s) and 51 healthy climbers (control group) in a Japanese population. We examined 2 polymorphisms of the eNOS gene, including the Glu298Asp variant and 27-base pair (bp) variable numbers of tandem repeats using polymerase chain reaction followed by restriction fragment length polymorphism. The Asp allelic frequency of the Glu298Asp variant was 25.6% in the HAPE-s and 9.8% in the controls, which was significantly different between the two groups (P =0.0044). The eNOS4a allelic frequency of 27-bp variable numbers of tandem repeats was 23.2% in the HAPE-s, significantly higher than that of 6.9% in the controls (P =0.0016). In HAPE-s group, 11 of 41 (26.8%) subjects possessed simultaneously both of the two significant alleles, but among the controls, none did, which showed a high statistical difference between the two groups (P =0.000059). Conclusions—Both polymorphisms of the eNOS gene were significantly associated with HAPE. A genetic background may underlie the impaired NO synthesis in the pulmonary circulation of HAPE-s. These polymorphisms could be genetic markers for predicting the susceptibility to HAPE.

Inflammatory cytokines in BAL fluid and pulmonary hemodynamics in high-altitude pulmonary edema.

To evaluate the pathogenesis of high-altitude pulmonary edema (HAPE), we performed bronchoalveolar lavage (BAL) and pulmonary hemodynamic studies in seven patients with HAPE at its early stage. We measured cell counts, biochemical contents, and concentrations of pro-inflammatory cytokines including interleukin (IL)-1, IL-6, IL-8 and tumor necrosis factor (TNF)-alpha and of anti-inflammatory cytokines including IL-1 receptor antagonist (ra) and IL-10 in the BAL fluid (BALF). All patients showed increased counts for total cells, alveolar macrophages, neutrophils and lymphocytes, and markedly elevated concentrations of proteins, lactate dehydrogenase, IL-1beta, IL-6, IL-8, TNF-alpha and IL-1ra. The levels of IL-1alpha and IL-10 were not increased. Patients also showed pulmonary hypertension with normal wedge pressure. Both the driving pressure obtained as pulmonary arterial pressure minus wedge pressure and the PaO2 under room air were significantly correlated with the concentrations of IL-6 and TNF-alpha in the BALF. These findings suggest that the inflammatory cytokines play a role at the early stage of HAPE and might be related to pulmonary hypertension.

Clinical characteristics of combined pulmonary fibrosis and emphysema

Background and objective:  Patients with combined pulmonary fibrosis and emphysema (CPFE) are sometimes seen, and we speculate that these patients have some different clinical characteristics from COPD patients. This study clarifies the clinical characteristics of CPFE patients.

Sputum eosinophilia can predict responsiveness to inhaled corticosteroid treatment in patients with overlap syndrome of COPD and asthma

Background Chronic obstructive pulmonary disease (COPD) and asthma may overlap and converge in older people (overlap syndrome). It was hypothesized that patients with overlap syndrome may have different clinical characteristics such as sputum eosinophilia, and better responsiveness to treatment with inhaled corticosteroid (ICS). Methods Sixty-three patients with stable COPD (forced expiratory volume in 1 second [FEV1] ≤80%) underwent pulmonary function tests, including reversibility of airflow limitation, arterial blood gas analysis, analysis of inflammatory cells in induced sputum, and chest high-resolution computed tomography. The inclusion criteria for COPD patients with asthmatic symptoms included having asthmatic symptoms such as episodic breathlessness, wheezing, cough, and chest tightness worsening at night or in the early morning (COPD with asthma group). The clinical features of COPD patients with asthmatic symptoms were compared with those of COPD patients without asthmatic symptoms (COPD without asthma group). Results The increases in FEV1 in response to treatment with ICS were significantly higher in the COPD with asthma group. The peripheral eosinophil counts and sputum eosinophil counts were significantly higher. The prevalence of patients with bronchial wall thickening on chest high-resolution computed tomography was significantly higher. A significant correlation was observed between the increases in FEV1 in response to treatment with ICS and sputum eosinophil counts, and between the increases in FEV1 in response to treatment with ICS and the grade of bronchial wall thickening. Receiver operating characteristic curve analysis revealed 82.4% sensitivity and 84.8% specificity of sputum eosinophil count for detecting COPD with asthma, using 2.5% as the cutoff value. Conclusion COPD patients with asthmatic symptoms had some clinical features. ICS should be considered earlier as a potential treatment in such patients. High sputum eosinophil counts and bronchial wall thickening on chest high-resolution computed tomography might therefore be a good predictor of response to ICS.

Cytokines in bronchoalveolar lavage fluid in patients with high altitude pulmonary oedema at moderate altitude in Japan.

BACKGROUND: The precise mechanism of high altitude pulmonary oedema (HAPE) remains unclear. The purpose of this study was to evaluate the role of cytokines and P-selectin in the development of HAPE which occurred at moderate altitude in Japan. METHODS: The following cellular and biochemical markers and chemotactic cytokines were measured in the bronchoalveolar (BAL) fluid from four patients with HAPE at 2857-3180 m in the Japanese Alps: total proteins, albumin, lactate dehydrogenase (LDH), and interleukin (IL)-1 alpha, IL-1 beta, IL-1 receptor antagonist (ra), IL-6, IL-8, IL-10, tumour necrosis factor (TNF)-alpha, and the soluble form of P-selectin. RESULTS: At admission there were significant increases in the levels of total cells, especially macrophages and neutrophils, total protein, albumin and LDH when compared with 13 healthy individuals. Furthermore, the levels of IL-1 beta, IL-6, IL-8, and TNF-alpha were also considerably increased but returned quickly to the normal ranges or were not detected after recovery. The levels of IL-1 alpha, IL-10, and P-selectin did not change. CONCLUSIONS: These results suggest that an inflammatory process almost identical with acute respiratory distress syndrome (ARDS) may occur in HAPE, but that these changes are transient and are not associated with any increase in P-selectin levels in the BAL fluid.

Enhanced levels of prostaglandin E2 and matrix metalloproteinase-2 correlate with the severity of airflow limitation in stable COPD.

Background and objective:  Cyclooxygenase‐2 (COX‐2) and its product prostaglandin E2 (PGE2) have been demonstrated to play critical roles in inflammation in respiratory diseases. However, the role of COX‐2 in airway remodelling in COPD remains to be elucidated. Matrix metalloproteinase‐2 (MMP‐2) is associated with both inflammation and airway remodelling in COPD. The objective of this study was to measure the expression of COX‐2 and the concentrations of PGE2 and MMP‐2, and to investigate the role of COX‐2 and PGE2 in airflow limitation mediated by MMP‐2, in the pathogenesis of COPD.

Association of High-Altitude Pulmonary Edema With the Major Histocompatibility Complex

BACKGROUND A constitutional susceptibility has been suggested in the development of high-altitude pulmonary edema (HAPE) because HAPE generally affects healthy young people, some of whom suffer recurrent episodes. We examined whether immunogenetic susceptibility is present in HAPE-susceptible subjects. METHODS AND RESULTS The frequencies of human leukocyte antigen (HLA) alleles in 28 male and 2 female subjects with a history of HAPE were compared with those in 100 healthy volunteers. We assayed the HLA-A, -B, -C, -DR, and -DQ antigens serologically. The pulmonary hemodynamics on admission to the hospital and the ventilatory response to hypoxia and hypercapnia were retrospectively examined in 10 of the HAPE-susceptible subjects. HLA-DR6 was positive in 14 (46.7%) of the subjects with HAPE but only 16.0% of the control subjects (P=.0005), and HLA-DQ4 was positive in 12 (40.0%) of the subjects with HAPE but only 10.0% of the control subjects (P=.0001). HLA-DR6 or HLA-DQ4 was positive in 8 (100%) of the subjects with recurrent HAPE. The pulmonary arterial pressure on admission of the HLA-DR6-positive subjects with HAPE was significantly higher than that of the HLA-DR6-negative subjects with HAPE. CONCLUSIONS There were significant associations of HAPE with HLA-DR6 and HLA-DQ4 and of pulmonary hypertension with HLA-DR6. An immunogenetic susceptibility, which is associated with HLA class II alleles located within the major histocompatibility complex, may underlie the development of HAPE, at least in some of its forms.

Consensus statement for the diagnosis and treatment of drug-induced lung injuries.

Keishi Kubo, Arata Azuma, Minoru Kanazawa, Hideto Kameda, Masahiko Kusumoto, Akihiko Genma, Yasuo Saijo, Fumikazu Sakai, Yukihiko Sugiyama, Koichiro Tatsumi, Makoto Dohi, Hitoshi Tokuda, Shu Hashimoto, Noboru Hattori, Masayuki Hanaoka, Yuh Fukuda, the Japanese Respiratory Society Committee for formulation of Consensus statement for the diagnosis and treatment of drug-induced lung injuries Nagano Prefectural Hospital Organization, Japan Division of Pulmonary Medicine, Infections Diseases, and Oncology, Department of Internal Medicine, Nippon Medical School, Japan Department of Respiratory Medicine, Saitama Medical University, Japan Division of Rheumatology, Department of Internal Medicine, School of Medicine, Keio University, Japan Department of Diagnostic Radiology, National Cancer Center Hospital, Japan Department of Medical Oncology, Niigata University Graduate School of Medical and Dental Sciences, Japan Department of Diagnostic Radiology, Saitama International Medical Center, Saitama Medical University, Japan Division of Pulmonary Medicine, Department of Internal Medicine, Jichi Medical University, Japan Department of Respirology, Chiba University Graduate School of Medicine, Japan Department of Allergy and Rheumatology, Tokyo University Graduate School of Medicine, Japan Department of Respiratory Medicine, Social Insurance Central General Hospital, Japan Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Japan Department of Molecular and Internal Medicine, Hiroshima University Graduate School of Biomedical & Health Sciences, Japan Department of Analytic Human Pathology, Graduate School of Medicine, Nippon Medical School, Japan