Shinichi Takatsuki

Efficacy of immunoglobulin plus prednisolone for prevention of coronary artery abnormalities in severe Kawasaki disease (RAISE study): a randomised, open-label, blinded-endpoints trial

BACKGROUND Evidence indicates that corticosteroid therapy might be beneficial for the primary treatment of severe Kawasaki disease. We assessed whether addition of prednisolone to intravenous immunoglobulin with aspirin would reduce the incidence of coronary artery abnormalities in patients with severe Kawasaki disease. METHODS We did a multicentre, prospective, randomised, open-label, blinded-endpoints trial at 74 hospitals in Japan between Sept 29, 2008, and Dec 2, 2010. Patients with severe Kawasaki disease were randomly assigned by a minimisation method to receive either intravenous immunoglobulin (2 g/kg for 24 h and aspirin 30 mg/kg per day) or intravenous immunoglobulin plus prednisolone (the same intravenous immunoglobulin regimen as the intravenous immunoglobulin group plus prednisolone 2 mg/kg per day given over 15 days after concentrations of C-reactive protein normalised). Patients and treating physicians were unmasked to group allocation. The primary endpoint was incidence of coronary artery abnormalities during the study period. Analysis was by intention to treat. This trial is registered with the University Hospital Medical Information Network clinical trials registry, number UMIN000000940. FINDINGS We randomly assigned 125 patients to the intravenous immunoglobulin plus prednisolone group and 123 to the intravenous immunoglobulin group. Incidence of coronary artery abnormalities was significantly lower in the intravenous immunoglobulin plus prednisolone group than in the intravenous immunoglobulin group during the study period (four patients [3%] vs 28 patients [23%]; risk difference 0·20, 95% CI 0·12-0·28, p<0·0001). Serious adverse events were similar between both groups: two patients had high total cholesterol and one neutropenia in the intravenous immunoglobulin plus prednisolone group, and one had high total cholesterol and another non-occlusive thrombus in the intravenous immunoglobulin group. INTERPRETATION Addition of prednisolone to the standard regimen of intravenous immunoglobulin improves coronary artery outcomes in patients with severe Kawasaki disease in Japan. Further study of intensified primary treatment for this disease in a mixed ethnic population is warranted. FUNDING Japanese Ministry of Health, Labour and Welfare.

A genome-wide association study identifies three new risk loci for Kawasaki disease

We performed a genome-wide association study (GWAS) of Kawasaki disease in Japanese subjects using data from 428 individuals with Kawasaki disease (cases) and 3,379 controls genotyped at 473,803 SNPs. We validated the association results in two independent replication panels totaling 754 cases and 947 controls. We observed significant associations in the FAM167A-BLK region at 8p22-23 (rs2254546, P = 8.2 × 10−21), in the human leukocyte antigen (HLA) region at 6p21.3 (rs2857151, P = 4.6 × 10−11) and in the CD40 region at 20q13 (rs4813003, P = 4.8 × 10−8). We also replicated the association of a functional SNP of FCGR2A (rs1801274, P = 1.6 × 10−6) identified in a recently reported GWAS of Kawasaki disease. Our findings provide new insights into the pathogenesis and pathophysiology of Kawasaki disease.

Clinical Safety, Pharmacokinetics, and Efficacy of Ambrisentan Therapy in Children With Pulmonary Arterial Hypertension

Recent trials in adult PAH revealed the efficacy of ambrisentan. However, in children with PAH, the clinical safety and pharmacokinetics of ambrisentan has not been well studied. Our aim was to investigate the clinical safety, pharmacokinetics, tolerability, and efficacy of endothelin receptor antagonist therapy with ambrisentan in children with pulmonary arterial hypertension (PAH). This retrospective cohort study provides clinical data from pediatric patients with PAH receiving ambrisentan as add‐on therapy or transition from bosentan. Safety included evaluation of adverse events including aminotransferase abnormalities. The clinical impact was evaluated by improvement from baseline in clinical variables. A total of 38 pediatric patients with PAH received ambrisentan. Fifteen of 38 patients were switched from bosentan to ambrisentan. The remaining 23 children were treated with ambrisentan as an add‐on therapy due to disease progression. In both transition and add‐on cases, mean pulmonary artery pressure significantly improved (transition; 55 ± 18 vs. 45 ± 20 mmHg, n = 13, P = 0.04, add‐on; 52 ± 17 vs. 45 ± 19 mmHg, n = 13, P = 0.03) during the follow‐up. World Health Organization functional class improved in 31% of patients, but one patient required an atrial septostomy due to disease progression during the follow‐up period (median, range; 20, 4–44 months). Five patients (13%) discontinued ambrisentan due to severe headache, lack of clinical efficacy, or near syncope. Ten patients (26%) had side effects associated with ambrisentan treatment, including nasal congestion, headache, and flushing. However, no patients had aminotransferase abnormalities and there were no deaths after initiation of ambrisentan during follow‐up. Pharmacokinetics were evaluated in sixteen children treated with ambrisentan from 2.5 mg to 10.0 mg; the mean peak plasma concentration was 738 ± 452 ng/ml, mean time to peak plasma concentration was 3.2 ± 2.1 hours, and mean area under the curve plasma concentration was 6657 ± 4246 ng·hour/ml. In conclusion, initial experience with ambrisentan in children suggests that treatment is safe with similar pharmacokinetics to those in adults and may improve PAH in some children. Pediatr Pulmonol. 2013; 48:27–34.

Circulating Fibrocytes Are Increased in Children and Young Adults with Pulmonary Hypertension

Chronic inflammation is an important component of the fibroproliferative changes that characterise pulmonary hypertensive vasculopathy. Fibrocytes contribute to tissue remodelling in settings of chronic inflammation, including animal models of pulmonary hypertension (PH). We sought to determine whether circulating fibrocytes were increased in children and young adults with PH. 26 individuals with PH and 10 with normal cardiac anatomy were studied. Fresh blood was analysed by flow cytometry for fibrocytes expressing CD45 and procollagen. Fibrocyte numbers were correlated to clinical and haemodynamic parameters, and circulating CC chemokine ligand (CCL)2 and CXC chemokine ligand (CXCL)12 levels. We found an enrichment of circulating fibrocytes among those with PH. No differences in fibrocytes were observed among those with idiopathic versus secondary PH. Higher fibrocytes correlated to increasing mean pulmonary artery pressure and age, but not to length or type of treatment. Immunofluorescence analysis confirmed flow sorting specificity. Differences in plasma levels of CCL2 or CXCL12, which could mobilise fibrocytes from the bone marrow, were not found. We conclude that circulating fibrocytes are significantly increased in individuals with PH compared with controls. We speculate that these cells might play important roles in vascular remodelling in children and young adults with pulmonary hypertension.

Effectiveness and Safety of Inhaled Treprostinil for the Treatment of Pulmonary Arterial Hypertension in Children

The introduction of prostanoid therapy has revolutionized the treatment of pulmonary arterial hypertension (PAH). However, continuous intravenous prostacyclin infusion poses significant risks and challenges, particularly in children. Inhaled treprostinil has been shown to be safe and efficacious in adults. This study describes the safety and efficacy of inhaled treprostinil in children with PAH. A retrospective analysis of 29 children treated with inhaled treprostinil for ≥6 weeks was performed. Effects of inhaled treprostinil on exercise capacity, functional class, and echocardiographic and hemodynamic data were evaluated. Adverse events were documented. Patients received 3 to 9 breaths (6 μg/breath) of inhaled treprostinil 4 times/day. All were receiving background PAH therapy; 12 had previously received parenteral prostanoid. Inhaled treprostinil was discontinued in 4 patients because of symptoms including cough and bronchospasm (n = 3) and progression of PAH (n = 1). Mild side effects including cough (n = 9) and sore throat (n = 6) did not require discontinuation of therapy. World Health Organization functional class improved in 19 and was unchanged in 10; exercise capacity significantly improved with the 6-minute walk distance, improving on follow-up from 455.7 ± 71.5 to 498 ± 70 m (p = 0.01) and peak oxygen consumption increasing from 25.5 ± 10.2 to 27.4 ± 10 (p = 0.04). In conclusion, inhaled treprostinil was associated with improvement in exercise capacity and World Health Organization functional class when added to background targeted PAH therapy in children and had an acceptable safety profile. Based on these early data, further study of inhaled treprostinil appears warranted in pediatric patients with PAH.

Tissue Doppler Imaging Predicts Adverse Outcome in Children with Idiopathic Pulmonary Arterial Hypertension

OBJECTIVE To evaluate the clinical utility of tissue Doppler imaging (TDI) in assessment of disease severity and prognostic value in children with idiopathic pulmonary arterial hypertension (PAH). STUDY DESIGN A prospective study was performed to evaluate TDI velocities (systolic myocardial velocity, early diastolic myocardial relaxation velocity [Em], late diastolic myocardial velocity associated with atrial contraction), brain natriuretic peptide, New York Heart Association (NYHA) functional class, and hemodynamics in 51 children (mean age; 11.6 years) with idiopathic PAH. Fifty-one healthy children with comparable demographics served as controls. RESULTS Em, Em/late diastolic myocardial velocity associated with atrial contraction ratio, and systolic myocardial velocity at mitral annulus, septum, and tricuspid annulus in PAH were significantly reduced compared with controls. Tricuspid Em had significant inverse correlations with plasma brain natriuretic peptide levels (r = -0.60, P < .001), right ventricular end-diastolic pressure (r = -0.79, P < .001), and mean pulmonary arterial pressure (r = -0.67, P < .001). Statistically significant differences were observed in tricuspid Em between NYHA functional class II vs combined III and IV (mean and SD; 11.9 ± 4.2 cm/s vs 8.2 ± 3.6 cm/s, respectively, P = .002). Cumulative event-free survival rate was significantly lower when tricuspid Em was ≤8 cm/s (log-rank test, P < .001) CONCLUSIONS Tricuspid Em velocity correlated with NYHA functional class as disease severity and may serve as a useful prognostic marker in children with idiopathic PAH. The present study is the initial report to evaluate TDI velocities against midterm outcome variables in a relatively large pediatric PAH population.

B-type Natriuretic Peptide and Amino-terminal Pro-B-type Natriuretic Peptide in Pediatric Patients with Pulmonary Arterial Hypertension

OBJECTIVES B-type natriuretic peptide (BNP) and the amino-terminal fragment (NTproBNP) correlate with clinical variables, but have not been simultaneously studied in a large number of pediatric patients with pulmonary arterial hypertension (PAH). The purpose of our investigation was to compare BNP and NTproBNP with clinical indicators of disease in a pediatric PAH population for which biomarkers are much needed. DESIGN We retrospectively compared BNP and NTproBNP levels with exercise capacity, echocardiographic data, and hemodynamics in PAH patients under 21 years old. Two hundred sixty-three blood samples from 88 pediatric PAH patients were obtained, with BNP and NTproBNP drawn at the same time. RESULTS There was a correlation between BNP and NTproBNP with mean pulmonary arterial pressure/mean systemic arterial pressure ratio (r= 0.40, P < .01; r= 0.45, P < .01; respectively), mean right atrial pressure (r= 0.48, P < .01; r= 0.48, P < .01), and tricuspid regurgitant velocity (r= 0.36, P < .01; r= 0.41, P < .01). BNP and NTproBNP are associated with 6-minute walk distance, mean pulmonary arterial pressure, mean pulmonary arterial pressure/mean systemic arterial pressure ratio, mean right atrial pressure, pulmonary vascular resistance index, and tricuspid regurgitant velocity when investigated longitudinally. On the average, a 1-unit increase in log BNP or NTproBNP was associated with 4.5 units × m(2) or 3.4 units × m(2) increase in pulmonary vascular resistance index, respectively. There was a strong correlation between log BNP and log NTproBNP measurements (r= 0.87, P < .01). CONCLUSION In pediatric PAH, BNP and NTProBNP are strongly correlated and predict changes in clinical variables and hemodynamics. In a cross-sectional analysis, NTproBNP correlated with echocardiographic and exercise data better than BNP; NTproBNP showed less within patient variability over time; therefore, NTproBNP can add additional information toward predicting these clinical measurements.

Coronary artery outcomes among children with Kawasaki disease in the United States and Japan.

OBJECTIVE It has been claimed that the aneurysm rate for Kawasaki disease (KD) patients in Japan is lower than in the U.S. However it has been difficult to compare coronary artery (CA) outcomes between the two countries because of different definitions for CA abnormalities. Therefore, we compared CA internal diameters between Japanese and U.S. KD patients using standard definitions and methods. STUDY DESIGN We retrospectively reviewed CA outcomes in 1082 KD patients from 2 centers in the U.S. and 3 centers in Japan and compared Z-max scores (maximum internal diameter for the left anterior descending or right coronary artery expressed as standard deviation units from the mean (Z-score) normalized for body surface area) obtained within 12 weeks after onset and calculated using two different regression equations from Canada (Dallaire) and Japan (Fuse). We defined a Z-max of < 2.5 as normal and a Z-max of ≥ 10 as giant aneurysm. RESULT The median Z-max for the U.S. and Japanese subjects was 1.9 and 2.3 SD units, respectively (p < 0.001). There was no significant difference in rates of patients with Z-max ≥ 5.0 between the countries. In a multivariable model adjusting for age, sex, and treatment response, being Japanese was still associated with a higher Z-max score. CONCLUSION Previously reported differences in aneurysm rates between Japan and the U.S. likely resulted from use of different definitions and nomenclature. Adoption of Z-scores as a standard for reporting CA internal diameters will allow meaningful comparisons among different countries and will facilitate international, collaborative clinical trials.

Circulating Myeloid-Derived Suppressor Cells Are Increased and Activated in Pulmonary Hypertension

BACKGROUND Myeloid-derived suppressor cells (MDSCs) are increased in inflammatory and autoimmune disorders and orchestrate immune cell responses therein. Pulmonary hypertension (PH) is associated with inflammation, autoimmunity, and lung vascular remodeling. Immature myeloid cells are found in the lungs of humans and animals with PH, and we hypothesized that they would be increased in the blood of patients with PH compared with control subjects. METHODS Twenty-six children with PH and 10 undergoing cardiac catheterization for arrhythmia ablation were studied. Five milliliters of fresh blood were analyzed using flow cytometry. Results were confirmed using magnetic bead sorting and immunofluorescence, while quantitative polymerase chain reaction and intracellular urea concentration assays were used as measures of MDSC arginase-1 activation. RESULTS Flow cytometry demonstrated enrichment of circulating MDSCs among patients with PH (n = 26; mean, 0.271 × 10(6) cells/mL ± 0.17; 1.86% of CD45(+) population ± 1.51) compared with control subjects (n = 10; mean, 0.176 × 10(6) cells/mL ± 0.05; 0.57% of CD45(+) population ± 0.29; P < .05). Higher numbers of circulating MDSCs correlated to increasing mean pulmonary artery pressure (r = 0.510, P < .05). Among patients with PH, female patients had a twofold increase in MDSCs compared with male patients. Immunofluorescence analysis confirmed the results of flow cytometry. Quantitative reverse transcription polymerase chain reaction assay results for arginase-1 and measurement of intracellular urea concentration revealed increased activity of MDSCs from patients with PH compared with control subjects. CONCLUSIONS Circulating activated MDSCs are significantly increased in children with PH compared with control subjects. Further investigation of these cells is warranted, and we speculate that they might play significant immunomodulatory roles in the disease pathogenesis of PH.

Severe pulmonary emphysema in a girl with interstitial deletion of 2q24.2q24.3 including ITGB6

Owing to the large size of chromosome 2, partial monosomy of the long arm of this chromosome gives rise to many specific phenotypes. We report on a 2‐month‐old girl with an interstitial deletion of 2q24.2q24.3, which was confirmed by microarray‐based comparative genomic hybridization analysis. The patient showed delayed growth and mental retardation, early myoclonic seizures, and characteristic dysmorphic features including thick arched eyebrows, upslanting palpebral fissures, long eyelashes, depressed nasal bridge, short nose, long philtrum, small mouth, micrognathia, and low set ears. Her early myoclonic seizures were likely due to haploinsufficiency of SCN1A and SCN2A, which are included in the deletion region. When she experienced acute bronchopneumonia, she showed severe pulmonary emphysema. The deletion region of 2q24.2 includes the integrin β6 gene (ITGB6), which may prevent acute lung injury and pulmonary emphysema. Many previously reported patients with deletions of 2q24.2 showed poor outcomes because of respiratory failure. These observations suggest the possibility of a strong relationship between haploinsufficiency of ITGB6 and pulmonary dysfunction.