IL-6/gp130 signaling in CD4+ T cells drives the pathogenesis of pulmonary hypertension.

Pulmonary arterial hypertension (PAH) is characterized by stenosis and occlusions of small pulmonary arteries, leading to elevated pulmonary arterial pressure and right heart failure. Although accumulating evidence shows the importance of interleukin (IL)-6 in the pathogenesis of PAH, the target cells of IL-6 are poorly understood. Using mice harboring the floxed allele of gp130, a subunit of the IL-6 receptor, we found substantial Cre recombination in all hematopoietic cell lineages from the primitive hematopoietic stem cell level in SM22α-Cre mice. We also revealed that a CD4+ cell-specific gp130 deletion ameliorated the phenotype of hypoxia-induced pulmonary hypertension in mice. Disruption of IL-6 signaling via deletion of gp130 in CD4+ T cells inhibited phosphorylation of signal transducer and activator of transcription 3 (STAT3) and suppressed the hypoxia-induced increase in T helper 17 cells. To further examine the role of IL-6/gp130 signaling in more severe PH models, we developed Il6 knockout (KO) rats using the CRISPR/Cas9 system and showed that IL-6 deficiency could improve the pathophysiology in hypoxia-, monocrotaline-, and Sugen5416/hypoxia (SuHx)-induced rat PH models. Phosphorylation of STAT3 in CD4+ cells was also observed around the vascular lesions in the lungs of the SuHx rat model, but not in Il6 KO rats. Blockade of IL-6 signaling had an additive effect on conventional PAH therapeutics, such as endothelin receptor antagonist (macitentan) and soluble guanylyl cyclase stimulator (BAY41-2272). These findings suggest that IL-6/gp130 signaling in CD4+ cells plays a critical role in the pathogenesis of PAH.

The real-world clinical decisions of physicians in the management of Takayasu arteritis and giant cell arteritis in Japan: A cross-sectional web-questionnaire survey.

OBJECTIVES: To access the real-world clinical management of physicians who treat Takayasu arteritis (TAK) and giant cell arteritis (GCA) after the publication of the Japanese Circulation Society (JCS) 2017 Guidelines for the Management of Vasculitis Syndrome. METHODS: This descriptive, cross-sectional study utilized self-administered electronic questionnaires, which were answered in February 2022 by physicians treating TAK or GCA and registered with Macromill Inc. RESULTS: The 329 survey respondents comprised 110 cardiologists, 110 rheumatologists, 34 cardiovascular surgeons, 24 surgeons, 35 internal medicine physicians, 13 nephrologists, and 7 pediatricians. The 2017 JCS Guidelines were the most commonly referenced information source for resolving clinical questions, accessed by 70% of respondents. Ophthalmoscopy was performed in only 50% of patients with TAK, and in 70% for GCA. The median percentages of patients who underwent 18F-fluorodeoxyglucose-positron emission tomography/computed tomography for TAK and GCA patients were 23% and 20% at diagnosis, respectively, and 10% each at follow-up within 12 months. Tocilizumab was the most frequently used medication in combination with glucocorticoids for both TAK and GCA, especially in remission induction therapy for relapsed patients. CONCLUSIONS: The majority of physician treating TAK and GCA referred to the 2017 JCS guidelines. This report clarified the current clinical practice for large vessel vasculitis in Japan, providing information for the next revision of the guidelines.

Demographic Traits, Clinical Status, and Comorbidities of Patients With Thromboangiitis Obliterans in Japan.

BACKGROUND: The latest demographics, clinical and living conditions, and comorbidities of patients with thromboangiitis obliterans (TAO) in Japan are unknown.Methods and Results: We conducted a retrospective cross-sectional survey using the annual database of the Japanese Ministry of Health, Labour and Welfare medical support system for patients with TAO between April 2013 and March 2014. This study included 3,220 patients (87.6% male), with current age ≥60 years in 2,155 patients (66.9%), including 306 (9.5%) patients aged ≥80 years. Overall, 546 (17.0%) had undergone extremity amputation. The median interval from onset to amputation was 3 years. Compared with never smokers (n=400), 2,715 patients with a smoking history had a higher amputation rate (17.7% vs. 13.0%, P=0.02, odds ratio [OR]=1.437, 95% confidence interval [CI]=1.058-1.953). A lower proportion of workers and students was seen among patients after amputation than among amputation-free patients (37.9% vs. 53.0%, P<0.0001, OR=0.542, 95% CI=0.449-0.654). Comorbidities, including arteriosclerosis-related diseases, were found even in patients in their 20-30 s. CONCLUSIONS: This large survey confirmed that TAO is not a life-threatening but an extremity-threatening disease that threatens patients' professional lives. Smoking history worsens patients' condition and extremity prognosis. Long-term total health support is required, including care of extremities and arteriosclerosis-related diseases, social life support, and smoking cessation.

Establishing clinical remission criteria for giant cell arteritis: Results of a Delphi exercise carried out by an expert panel of the Japan Research Committee of the Ministry of Health, Labour, and Welfare for Intractable Vasculitis.

OBJECTIVE: To develop a proposal for giant cell arteritis remission criteria in order to implement a treat-to-target algorithm. METHODS: A task force consisting of 10 rheumatologists, 3 cardiologists, 1 nephrologist, and 1 cardiac surgeon was established in the Large-vessel Vasculitis Group of the Japanese Research Committee of the Ministry of Health, Labour and Welfare for Intractable Vasculitis to conduct a Delphi survey of remission criteria for giant cell arteritis. The survey was circulated among the members over four reiterations with four face-to-face meetings. Items with a mean score of ≥4 were extracted as items for defining remission criteria. RESULTS: An initial literature review yielded a total of 117 candidate items for disease activity domains and treatment/comorbidity domains of remission criteria, of which 35 were extracted as disease activity domains (systematic symptoms, signs and symptoms of cranial and large-vessel area, inflammatory markers, and imaging findings). For the treatment/comorbidity domain, ≤5 mg/day of prednisolone 1 year after starting glucocorticoids was extracted. The definition of achievement of remission was the disappearance of active disease in the disease activity domain, normalization of inflammatory markers, and ≤5 mg/day of prednisolone. CONCLUSION: We developed proposals for remission criteria to guide the implementation of a treat-to-target algorithm for giant cell arteritis.

Organ Damage and Quality of Life in Takayasu Arteritis　- Evidence From a National Registry Analysis.

BACKGROUND: Takayasu arteritis, affecting primarily young women, damages large arteries and organs. We examined the impact of disease duration and sex on organ damage and quality of life using Japan's Intractable Disease Registry.Methods and Results: After refining data, 2,013 of 2,795 patients were included in the study. Longer disease duration was related to a lower prevalence of disease activity symptoms, a higher prevalence of organ damage, and a higher proportion of patients requiring nursing care. Compared with men, women tended to have an earlier onset age, exhibiting longer disease duration. A higher proportion of women had aortic regurgitation and required nursing care. The proportion of female patients in employment was lower than that of the general female population, whereas no difference was observed between male patients and the general male population. Logistic regression analysis revealed that age at surveillance, brain ischemia, visual impairment/loss, and ischemic heart disease were significant factors associated with high nursing care needs (Level ≥2, with daily activity limitations). CONCLUSIONS: Early diagnosis and effective treatment, particularly to prevent brain ischemia, visual impairment, and ischemic heart disease, may improve the quality of life of patients with Takayasu arteritis, especially women.

Current Immunosuppressive Treatment for Takayasu Arteritis.

Takayasu arteritis (TAK) is a rare disease characterized by inflammation of large blood vessels, which results in vascular stenosis, occlusion, and aneurysm formation. The principal treatment has been glucocorticoids, but the recent emergence of biological disease-modifying anti-rheumatic drugs (bDMARDs), represented by tocilizumab (TCZ), has significantly changed the treatment landscape. Both cardiologists and cardiovascular surgeons will encounter patients receiving these drugs who require catheterization, other invasive procedures, or surgery. Several bDMARDs have shown promise against TAK in clinical studies and their use is expected to increase in the future. Janus kinase inhibitors may also be effective. Here, we review the evidence supporting the use of TCZ and other immunosuppressants in TAK and provides an update on their status as well as the relevant guidelines.

A multicentre, large-scale, observational study of tocilizumab in patients with giant cell arteritis in Japan.

OBJECTIVES: In clinical trials, tocilizumab (TCZ) is efficacious in patients with giant cell arteritis (GCA). This study evaluated the real-world tolerability and effectiveness of TCZ in Japanese patients with GCA. METHODS: In this multicentre, prospective, phase 4, large-scale, observational study, patients with GCA (with no TCZ treatment 6 months before the study) were recruited from 71 centres across Japan. Patients received subcutaneous TCZ 162 mg weekly (observation period, 52 weeks). RESULTS: Of the 117 patients (female, 70.1%; mean age, 74.2 years; mean disease duration, 1.4 years; treated for new-onset GCA, 71.8%; presence of large-vessel lesions [LVLs], 61.5%; previous immunosuppressant use, 28.2%; glucocorticoids at baseline, 95.7% [mean: 22.4 mg/day]), 38.5% reported adverse events. The most common adverse events of special interest were neutropenia and leukopenia (7.7%), followed by serious infection (6.0%). The relapse-free proportion was 85.0%; relapse after remission, 6.0%; and no remission, 9.0%. At the last observation, 94.2% of relapse-free patients received a concomitant glucocorticoid dose of <10 mg/day. Fatigue, headache, neck pain and absence of LVLs were positively associated with the relapse. CONCLUSIONS: TCZ was effective and well tolerated in Japanese patients with GCA and may be an effective treatment option combined with glucocorticoids.

Gut dysbiosis is associated with aortic aneurysm formation and progression in Takayasu arteritis.

BACKGROUND: Takayasu arteritis (TAK) is an autoimmune large vessel vasculitis that affects the aorta and its major branches, eventually leading to the development of aortic aneurysm and vascular stenosis or occlusion. This retrospective and prospective study aimed to investigate whether the gut dysbiosis exists in patients with TAK and to identify specific gut microorganisms related to aortic aneurysm formation/progression in TAK. METHODS: We analysed the faecal microbiome of 76 patients with TAK and 56 healthy controls (HCs) using 16S ribosomal RNA sequencing. We examined the relationship between the composition of the gut microbiota and clinical parameters. RESULTS: The patients with TAK showed an altered gut microbiota with a higher abundance of oral-derived bacteria, such as Streptococcus and Campylobacter, regardless of the disease activity, than HCs. This increase was significantly associated with the administration of a proton pump inhibitor used for preventing gastric ulcers in patients treated with aspirin and glucocorticoids. Among patients taking a proton pump inhibitor, Campylobacter was more frequently detected in those who underwent vascular surgeries and endovascular therapy for aortic dilatation than in those who did not. Among the genus of Campylobacter, Campylobacter gracilis in the gut microbiome was significantly associated with clinical events related to aortic aneurysm formation/worsening in patients with TAK. In a prospective analysis, patients with a gut microbiome positive for Campylobacter were significantly more likely to require interventions for aortic dilatation than those who were negative for Campylobacter. Furthermore, patients with TAK who were positive for C. gracilis by polymerase chain reaction showed a tendency to have severe aortic aneurysms. CONCLUSIONS: A specific increase in oral-derived Campylobacter in the gut may be a novel predictor of aortic aneurysm formation/progression in patients with TAK.

Nationwide clinical and epidemiological study of large-vessel vasculitis in Japan in 2017.

OBJECTIVE: We conducted a nationwide epidemiological study to estimate the number of patients with Takayasu arteritis (TAK) and giant cell arteritis (GCA) in Japan and to describe the clinical characteristics of these patients. METHODS: The first survey was designed to estimate the number of patients with TAK and GCA who were treated at medical institutions in Japan in 2017. The second survey was designed to collect data on the clinical characteristics of the patients who were reported in the first survey. RESULTS: Of the 3495 institutions selected for the first survey, 1960 (56.1%) responded. The number of patients with clinically diagnosed TAK and GCA was estimated to be 5320 (95% confidence interval, 4810-5820) and 3200 (95% confidence interval, 2830-3570), respectively. Aortic regurgitation was reported in 35% of patients with TAK, and eye-related comorbidities were observed in 30.4% of patients with GCA. The common carotid and internal carotid arteries were the most frequently involved in patients with TAK (62.7%). Subclavian artery lesions and thoracic or abdominal aorta lesions were reported in 31% and 42.6% of patients with GCA, respectively. CONCLUSIONS: The number of patients with TAK and GCA was estimated simultaneously, and significant differences in clinical characteristics were observed between the two diseases.

Association between the patterns of large-vessel lesions and treatment outcomes in patients with large-vessel giant cell arteritis.

OBJECTIVES: We aimed to identify associations between patterns of large-vessel lesions of large-vessel giant cell arteritis (LV-GCA) and treatment outcomes. METHODS: We extracted data on 68 newly diagnosed patients with LV-GCA from a retrospective, multi-centric, nationwide registry of GCA patients treated with glucocorticoids between 2007 and 2014. Patients with aortic lesions were identified based on the findings from contrast-enhanced computed tomography, magnetic resonance imaging, or positron emission tomography-computed tomography (Group 2, n = 49). Patients without aortic lesions were subdivided into LV-GCA with or without subclavian lesions defined as Group 1 (n = 9) or Group 3 (n = 10), respectively. The primary outcome evaluation was failure to achieve clinical remission by Week 24 and/or relapse within 104 weeks. RESULTS: The mean age and proportion of patients with cranial lesions and polymyalgia rheumatica in Group 2 were numerically lower than in the other two groups. Large-vessel lesions in Group 3 included carotid, pulmonary, renal, hepatic, or mesenteric lesions. The cumulative rate of poor treatment outcomes >2 years was 11.1%, 55.3%, and 88.0% in Groups 1, 2, and 3, respectively (by Kaplan-Meier analysis). The mean time to poor outcome was significantly different between the groups. CONCLUSIONS: Classification by subclavian and aortic lesions may be useful to determine treatment strategy.

A multicentre, large-scale, observational study of tocilizumab in patients with Takayasu arteritis in Japan: The ACTEMRA® (ACT)-Bridge study.

OBJECTIVES: We evaluated the real-world tolerability and effectiveness of tocilizumab in Japanese patients with Takayasu arteritis (TAK). METHODS: Patients with TAK who had not received tocilizumab in the previous 6 months were enrolled in ACTEMRA® (ACT)-Bridge, a phase 4, observational study, from 66 Japanese institutions (enrolment period, September 2017 to September 2020) and received weekly subcutaneous tocilizumab 162 mg (observation period, 52 weeks). RESULTS: Among 120 patients included (mean age, 38.4 years; mean disease duration, 7.7 years; treated for relapse, 50.8%; previous immunosuppressant use, 57.5%; glucocorticoid use at baseline, 97.5%), 49 (40.8%) reported adverse events. The most common adverse event of special interest was serious infection (7.5%). Relapse was observed in 24 (20.0%) patients (0.8%, 2.5%, and 16.7% reporting ≥3, 2, and 1 relapses, respectively). The reasons for diagnosing relapse included chest and back pain (45.8%), neck pain (25.0%), fatigue (16.7%), fever and headache (12.5% each), abnormal imaging findings (50.0%), and elevated inflammatory markers (16.7%). At the last observation, 83.0% of relapse-free patients recorded a concomitant glucocorticoid dose (prednisolone equivalent) <10 mg/day. CONCLUSIONS: This study demonstrated the effectiveness of tocilizumab in patients with TAK, with no new safety concerns. Tocilizumab plus glucocorticoids may be considered a treatment option for TAK.

Regnase-1 Prevents Pulmonary Arterial Hypertension Through mRNA Degradation of Interleukin-6 and Platelet-Derived Growth Factor in Alveolar Macrophages.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a type of pulmonary hypertension (PH) characterized by obliterative pulmonary vascular remodeling, resulting in right-sided heart failure. Although the pathogenesis of PAH is not fully understood, inflammatory responses and cytokines have been shown to be associated with PAH, in particular, with connective tissue disease-PAH. In this sense, Regnase-1, an RNase that regulates mRNAs encoding genes related to immune reactions, was investigated in relation to the pathogenesis of PH. METHODS: We first examined the expression levels of ZC3H12A (encoding Regnase-1) in peripheral blood mononuclear cells from patients with PH classified under various types of PH, searching for an association between the ZC3H12A expression and clinical features. We then generated mice lacking Regnase-1 in myeloid cells, including alveolar macrophages, and examined right ventricular systolic pressures and histological changes in the lung. We further performed a comprehensive analysis of the transcriptome of alveolar macrophages and pulmonary arteries to identify genes regulated by Regnase-1 in alveolar macrophages. RESULTS: ZC3H12A expression in peripheral blood mononuclear cells was inversely correlated with the prognosis and severity of disease in patients with PH, in particular, in connective tissue disease-PAH. The critical role of Regnase-1 in controlling PAH was also reinforced by the analysis of mice lacking Regnase-1 in alveolar macrophages. These mice spontaneously developed severe PAH, characterized by the elevated right ventricular systolic pressures and irreversible pulmonary vascular remodeling, which recapitulated the pathology of patients with PAH. Transcriptomic analysis of alveolar macrophages and pulmonary arteries of these PAH mice revealed that Il6, Il1b, and Pdgfa/b are potential targets of Regnase-1 in alveolar macrophages in the regulation of PAH. The inhibition of IL-6 (interleukin-6) by an anti-IL-6 receptor antibody or platelet-derived growth factor by imatinib but not IL-1ß (interleukin-1ß) by anakinra, ameliorated the pathogenesis of PAH. CONCLUSIONS: Regnase-1 maintains lung innate immune homeostasis through the control of IL-6 and platelet-derived growth factor in alveolar macrophages, thereby suppressing the development of PAH in mice. Furthermore, the decreased expression of Regnase-1 in various types of PH implies its involvement in PH pathogenesis and may serve as a disease biomarker, and a therapeutic target for PH as well.

Establishing clinical remission criteria and the framework of a treat-to-target algorithm for Takayasu arteritis: Results of a Delphi exercise carried out by an expert panel of the Japan Research Committee of the Ministry of Health, Labour and Welfare for intractable vasculitis.

OBJECTIVES: To develop a proposal for remission criteria and a framework for a treat-to-target (T2T) algorithm for Takayasu arteritis (TAK). METHODS: A study group of the large-vessel vasculitis group of the Japanese Research Committee of the Ministry of Health, Labour and Welfare for Intractable Vasculitis consists of 10 rheumatologists, 5 cardiologists, 1 nephrologist, 1 vascular surgeon, 1 cardiac surgeon, and 2 paediatric rheumatologists. A Delphi survey of remission criteria items was circulated among the study group over four reiterations. To develop the T2T algorithm, the study group conducted four face-to-face meetings and two rounds of Delphi together with three patients. RESULTS: Initial literature review resulted in a list of 117 candidate items for remission criteria, of which 56 items with a mean score of ≥4 (0-5) were extracted including disease activity domains and treatment/comorbidity domains. The study group provided six overarching principles for the T2T algorithm, two recommendations on treatment goals, five on evaluation of disease activity and imaging findings including positron emission tomography-computed tomography, and two on treatment intensification. CONCLUSIONS: We developed a T2T algorithm and proposals for standardised remission criteria by means of a Delphi exercise. These will guide future evaluation of different TAK treatment regimens.

Vascular imaging of patients with refractory Takayasu arteritis treated with tocilizumab: post hoc analysis of a randomized controlled trial.

OBJECTIVES: Tocilizumab, an anti-IL-6 receptor antibody, was investigated in patients with refractory Takayasu arteritis (TAK) in a phase 3 randomized controlled trial. In this post hoc analysis, we investigated whether tocilizumab treatment inhibited the progression of vascular lesions caused by TAK in these patients. METHODS: Included patients received at least one dose of tocilizumab and underwent CT at baseline and at week 48 after tocilizumab initiation. Three radiologists not involved in the original trial independently evaluated the CT images. Twenty-two arteries from each patient were assessed for change from baseline in wall thickness (primary endpoint), dilatation/aneurysm, stenosis/occlusion or wall enhancement for at least 96 weeks after tocilizumab initiation. Patient-level assessments were also conducted. RESULTS: In 28 patients, 86.7% of 22 arteries had improved or stable wall thickness at week 96. Proportions of patients with improved or stable, partially progressed or newly progressed lesions were 57.1%, 10.7% and 28.6%, respectively, for wall thickness; proportions with improved or stable lesions were 92.9% for dilatation/aneurysm, and 85.7% for stenosis/occlusion. Patients with newly progressed lesions, reflecting more refractory disease, were prescribed glucocorticoids at dosages that could not be reduced below 0.1 mg/kg/day at week 96. CONCLUSIONS: Approximately 60% of patients with TAK did not experience progression in wall thickness within 96 weeks after initiation of tocilizumab treatment. Few patients experienced progressed dilatation/aneurysm, or stenosis/occlusion. Wall thickness progression likely resulted from refractory TAK. Patients who experience this should be monitored regularly by imaging, and additional glucocorticoid or immunosuppressive treatment should be considered to avoid vascular progression. TRIAL REGISTRATION: Japan Pharmaceutical Information Centre number, JapicCTI-142616.

Aryl hydrocarbon receptor is essential for the pathogenesis of pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a devastating disease characterized by arteriopathy in the small to medium-sized distal pulmonary arteries, often accompanied by infiltration of inflammatory cells. Aryl hydrocarbon receptor (AHR), a nuclear receptor/transcription factor, detoxifies xenobiotics and regulates the differentiation and function of various immune cells. However, the role of AHR in the pathogenesis of PAH is largely unknown. Here, we explore the role of AHR in the pathogenesis of PAH. AHR agonistic activity in serum was significantly higher in PAH patients than in healthy volunteers and was associated with poor prognosis of PAH. Sprague-Dawley rats treated with the potent endogenous AHR agonist, 6-formylindolo[3,2-b]carbazole, in combination with hypoxia develop severe pulmonary hypertension (PH) with plexiform-like lesions, whereas Sprague-Dawley rats treated with the potent vascular endothelial growth factor receptor 2 inhibitors did not. Ahr-knockout (Ahr-/- ) rats generated using the CRISPR/Cas9 system did not develop PH in the SU5416/hypoxia model. A diet containing Qing-Dai, a Chinese herbal drug, in combination with hypoxia led to development of PH in Ahr+/+ rats, but not in Ahr-/- rats. RNA-seq analysis, chromatin immunoprecipitation (ChIP)-seq analysis, immunohistochemical analysis, and bone marrow transplantation experiments show that activation of several inflammatory signaling pathways was up-regulated in endothelial cells and peripheral blood mononuclear cells, which led to infiltration of CD4+ IL-21+ T cells and MRC1+ macrophages into vascular lesions in an AHR-dependent manner. Taken together, AHR plays crucial roles in the development and progression of PAH, and the AHR-signaling pathway represents a promising therapeutic target for PAH.

Pathological and clinical effects of interleukin-6 on human myocarditis.

BACKGROUND: Numerous basic studies have shown a relationship between interleukin-6 (IL-6) and the development or severity of myocarditis. However, there has been no study in which the effect of IL-6 levels in patients with myocarditis was evaluated. METHODS: We enrolled control patients (n = 12) and consecutive patients with acute myocarditis (n = 13), including lymphocytic, eosinophilic, and giant cell myocarditis, and investigated the pathological and clinical effects of IL-6 on human myocarditis. RESULTS: The serum IL-6 level in patients with myocarditis (16.7 [9.9, 103.8] pg/mL) was significantly higher than that in the control patients (1.4 [1.0, 1.9] pg/mL) (P<0.001). Immunohistochemical analysis showed that IL-6 was expressed in infiltrating inflammatory cells of endomyocardial biopsy samples from all patients with myocarditis. Moreover, the log-transformed value of serum IL-6 level showed significant positive correlations with serum creatine kinase (CK) level, CK-MB level, peak CK level, peak CK-MB level and C-reactive protein level (all P ≤ 0.005) and a negative correlation with the left ventricular (LV) ejection fraction (p = 0.014). We divided the patients with myocarditis into a low IL-6 group (9.9 [4.5, 14.2] pg/dL, n = 7) and a high IL-6 group (108.9 [51.1, 130.9] pg/dL, n = 6). The degree of infiltration of IL-6-expressing inflammatory cells in myocardial samples obtained from patients in the high IL-6 group was significantly more severe than that in samples obtained from patients in the low IL-6 group. Furthermore, patients in the high IL-6 group significantly more frequently received catecholamine therapy (P = 0.005), venoarterial extracorporeal membrane oxygenation (P = 0.029), and artificial respirator support (P = 0.021) in the acute phase of myocarditis. CONCLUSION: The results suggest that there is a strong impact of IL-6 on cardiac injury and dysfunction in patients with myocarditis.

Evaluation of right coronary vascular dysfunction in severe pulmonary hypertensive rats using synchrotron radiation microangiography.

Pulmonary hypertension (PH) causes cardiac hypertrophy in the right ventricle (RV) and eventually leads to RV failure due to persistently elevated ventricular afterload. We hypothesized that the mechanical stress on the RV associated with increased afterload impairs vasodilator function of the right coronary artery (RCA) in PH. Coronary vascular response was assessed using microangiography with synchrotron radiation (SR) in two well-established PH rat models, monocrotaline injection or the combined exposure to chronic hypoxia and vascular endothelial growth factor receptor blockade with Su5416 (SuHx model). In the SuHx model, the effect of the treatment with the nonselective endothelin-1 receptor antagonist (ERA), macitentan, was also examined. Myocardial viability was determined in SuHx model rats, using 18F-FDG Positron emission tomography (PET) and magnetic resonance imaging (MRI). Endothelium-dependent and endothelium-independent vasodilator responses were significantly attenuated in the medium and small arteries of severe PH rats. ERA treatment significantly improved RCA vascular function compared with the untreated group. ERA treatment improved both the decrease in ejection fraction and the increased glucose uptake, and reduced RV remodeling. In addition, the upregulation of inflammatory genes in the RV was almost suppressed by ERA treatment. We found impairment of vasodilator responses in the RCA of severe PH rat models. Endothelin-1 activation in the RCA plays a major role in impaired vascular function in PH rats and is partially restored by ERA treatment. Treatment of PH with ERA may improve RV function in part by indirectly attenuating right heart afterload and in part by associated improvements in right coronary endothelial function.NEW & NOTEWORTHY We demonstrated for the first time the impairment of vascular responses in the right coronary artery (RCA) of the dysfunctional right heart in pulmonary hypertensive rats in vivo. Treatment with an endothelin-1 receptor antagonist ameliorated vascular dysfunction in the RCA, enabled tissue remodeling of the right heart, and improved cardiac function. Our results suggest that impaired RCA function might also contribute to the early progression to heart failure in patients with severe pulmonary arterial hypertension (PAH). The endothelium of the coronary vasculature might be considered as a potential target in treatments to prevent heart failure in severe patients with PAH.

Current Trends in Epidemiology and Clinical Features of Thromboangiitis Obliterans in Japan　- A Nationwide Survey Using the Medical Support System Database.

BACKGROUND: The epidemiology and clinical features of thromboangiitis obliterans (TAO) in Japan have not been updated extensively.Methods and Results:This retrospective study used the Japanese Ministry of Health, Labour and Welfare (JMHLW) medical support system database and associated health insurance data. The number of medical financial support recipients registered as TAO patients and estimated prevalence of TAO decreased from fiscal year (FY) 2000 (10,089 and 7.95 [95% confidence interval, CI: 7.79-8.10] per 100,000 population) to FY 2010 (7,147 and 5.58 [95% Cl: 5.45-5.71] per 100,000) and leveled off until 2014. The prevalence of TAO among patients with peripheral arterial occlusive diseases declined from 7.15% (95% Cl: 7.00-7.31) in FY 2008 to 6.12% (95% Cl: 5.98-6.26) in FY 2014. Clinicodemographic features were obtained from 89 new recipients in FY 2013 and 2014: 12 (13%) women, 36 (40%) aged ≥50 years, 26 (29%) had probable onset age ≥50 years, 7 (8%) were non-smokers, and 12 (13%) had arteriosclerosis-related comorbidities. The symptoms were similar regardless of registration age, smoking history, or sex. Although 40 (45%) had digit ulcers, only 12 (13%) fulfilled Shionoya's criteria. They rarely had infrapopliteal lesions combined with upper extremity involvement or phlebitis. CONCLUSIONS: The prevalence of TAO has decreased in Japan. In the current diagnosis of TAO, various clinical characteristics including late onset, arteriosclerotic factors, non-smoking, or mild symptoms should be considered.