Kenichiro Yamamura

Kawasaki Disease-Specific Molecules in the Sera Are Linked to Microbe-Associated Molecular Patterns in the Biofilms

Background Kawasaki disease (KD) is a systemic vasculitis of unknown etiology. The innate immune system is involved in its pathophysiology at the acute phase. We have recently established a novel murine model of KD coronary arteritis by oral administration of a synthetic microbe-associated molecular pattern (MAMP). On the hypothesis that specific MAMPs exist in KD sera, we have searched them to identify KD-specific molecules and to assess the pathogenesis. Methods We performed liquid chromatography-mass spectrometry (LC-MS) analysis of fractionated serum samples from 117 patients with KD and 106 controls. Microbiological and LC-MS evaluation of biofilm samples were also performed. Results KD samples elicited proinflammatory cytokine responses from human coronary artery endothelial cells (HCAECs). By LC-MS analysis of KD serum samples collected at 3 different periods, we detected a variety of KD-specific molecules in the lipophilic fractions that showed distinct m/z and MS/MS fragmentation patterns in each cluster. Serum KD-specific molecules showed m/z and MS/MS fragmentation patterns almost identical to those of MAMPs obtained from the biofilms formed in vitro (common MAMPs from Bacillus cereus, Yersinia pseudotuberculosis and Staphylococcus aureus) at the 1st study period, and from the biofilms formed in vivo (common MAMPs from Bacillus cereus, Bacillus subtilis/Bacillus cereus/Yersinia pseudotuberculosis and Staphylococcus aureus) at the 2nd and 3rd periods. The biofilm extracts from Bacillus cereus, Bacillus subtilis, Yersinia pseudotuberculosis and Staphylococcus aureus also induced proinflammatory cytokines by HCAECs. By the experiments with IgG affinity chromatography, some of these serum KD-specific molecules bound to IgG. Conclusions We herein conclude that serum KD-specific molecules were mostly derived from biofilms and possessed molecular structures common to MAMPs from Bacillus cereus, Bacillus subtilis, Yersinia pseudotuberculosis and Staphylococcus aureus. Discovery of these KD-specific molecules might offer novel insight into the diagnosis and management of KD as well as its pathogenesis.

Variations in ORAI1 Gene Associated with Kawasaki Disease

Kawasaki disease (KD; MIM#61175) is a systemic vasculitis syndrome with unknown etiology which predominantly affects infants and children. Recent findings of susceptibility genes for KD suggest possible involvement of the Ca(2+)/NFAT pathway in the pathogenesis of KD. ORAI1 is a Ca(2+) release activated Ca(2+) (CRAC) channel mediating store-operated Ca(2+) entry (SOCE) on the plasma membrane. The gene for ORAI1 is located in chromosome 12q24 where a positive linkage signal was observed in our previous affected sib-pair study of KD. A common non-synonymous single nucleotide polymorphism located within exon 2 of ORAI1 (rs3741596) was significantly associated with KD (P = 0.028 in the discovery sample set (729 KD cases and 1,315 controls), P = 0.0056 in the replication sample set (1,813 KD cases vs. 1,097 controls) and P = 0.00041 in a meta-analysis by the Mantel-Haenszel method). Interestingly, frequency of the risk allele of rs3741596 is more than 20 times higher in Japanese compared to Europeans. We also found a rare 6 base-pair in-frame insertion variant associated with KD (rs141919534; 2,544 KD cases vs. 2,414 controls, P = 0.012). These data indicate that ORAI1 gene variations are associated with KD and may suggest the potential importance of the Ca(2+)/NFAT pathway in the pathogenesis of this disorder.

Thrombocytosis in asplenia syndrome with congenital heart disease: A previously unrecognized risk factor for thromboembolism

BACKGROUND Thrombocytosis and thromboembolic complications occur after splenectomy. However, there is no previous report investigating the presence of thrombocytosis and its association with thromboembolic events in patients having asplenia syndrome with congenital heart disease. METHODS Enrolled were 161 consecutive patients with functionally single ventricle who underwent cardiac catheterization between 1997 and 2010. They were divided into two groups: patients having asplenia (Group A, n=46) and patients having no asplenia (Group B, n=115). Aspirin therapy was employed in all patients after surgical interventions except for pulmonary artery banding. We retrospectively reviewed the platelet counts at each seven stage of cardiac catheterization (for pre- and postoperative evaluation of the first palliation, Glenn operation, and Fontan operation, and for late evaluation after Fontan operation), incidence of thromboembolic events, and other possible risk factors for thromboembolism. RESULTS The median platelet counts in Group A were consistently higher than those in Group B at any of the seven stages of cardiac catheterizations (p<0.002). The incidence of thromboembolic complications was also higher in Group A than that in Group B (28% vs. 10%, p=0.030). Univariate and multivariate logistic regression analyses showed that a platelet count of more than 550 × 10(9)/L at the first cardiac catheterization was associated with thromboembolic complications (Odds ratio 3.17; p=0.046). CONCLUSIONS Persistent thrombocytosis is present in patients with asplenia syndrome. It may greatly contribute to the development of thromboembolism during the management of congenital heart disease than expected.

Interventricular Dyssynchrony Using Tagging Magnetic Resonance Imaging Predicts Right Ventricular Dysfunction in Adult Congenital Heart Disease

PURPOSE Right ventricular (RV) failure and ventricular dyssynchrony are strong determinants of prognosis in patients with adult congenital heart disease (ACHD). The aim of this study was to investigate the relationship between interventricular dyssynchrony (IVD) using cine-tagged magnetic resonance imaging (MRI) and RV dysfunction in ACHD patients. MATERIALS AND METHODS Sixty-seven patients with ACHD (38 with repaired tetralogy of Fallot; 22 with atrial septal defect; seven with ventricular septal defect) underwent tagging MRI. Time curves of myocardial circumferential strains for RV and left ventricular (LV) free walls were delivered from short-axis cine-tagging images. Contraction delay between RV and LV free walls was computed by cross-correlation analysis of the two strain time curves and was defined as the IVD time (msec). RESULTS IVD was significantly greater for patients with RV ejection fraction (RVEF) <40% (116 ± 58 msec) than for patients with RVEF ≥ 40% (65 ± 54 msec) and was significantly greater for patients with RV systolic pressure ≥ 40 mm Hg (112 ± 59 msec) than for patients with RV systolic pressure <40 mm Hg (49 ± 28 msec). Receiver operating characteristic analysis revealed optimal IVD thresholds for detecting patients with RVEF <40% with C-statistics of 0.76 and patients with RV systolic pressure ≥ 40 mm Hg with C-statistics of 0.81. CONCLUSION Quantification of IVD was possible using RV and LV strains derived from tagging MRI. IVD, represented as the time difference between LV and RV contractions, correlates with RV dysfunction. IVD may thus offer an indicator for RV failure in ACHD.

Bacterial pericarditis caused by Lactobacillus iners in an infant

We report the case of a 6-month-old male infant with bacterial pericarditis due to Lactobacillus iners. Although the culture of pericardial fluid was negative, L. iners was identified by 16S rRNA gene amplification by polymerase chain reaction and a subsequent sequence analysis. This weakly pathogenic bacterium could develop a severe infection in infants.

A novel SCN5A mutation associated with the linker between III and IV domains of Nav1.5 in a neonate with fatal long QT syndrome

A male newborn weighing 2334 g was delivered at 37 weeks of gestation by caesarean section because of prenatal ultrasound findings of fetal hydrops with atrioventricualr block, ventriucular tachycardia (VT), and impaired ventricular function. In spite of the intravenous administration of lidocaine, VT continued. He developed poor perfusion and systemic hypotension. After the intravenous administration of amiodarone, VT was terminated. The electrocardiogram revealed an extremely prolonged corrected QT interval (860 ms) with 2:1 atrioventricular block. Unfortunately, he died 18 h after birth in spite of the administration of lidocaine, beta-blocker and magnesium. Mutational analysis identified a novel heterozygous de novo mutation (F1486del) in SCN5A. This mutation is associated with the IFM motif in the linker between III and IV domains of Na(v)1.5, which serves as an inactivation particle binding within the pore of sodium channels. This report demonstrates an interesting relationship between the clinical phenotype and the location of the mutation in long QT syndrome.

Systemic vascular phenotypes of Loeys-Dietz syndrome in a child carrying a de novo R381P mutation in TGFBR2: A case report

BackgroundLoeys–Dietz syndrome, also known as Marfan syndrome type II, is a rare connective tissue disorder caused by dominant mutations in transforming growth factor-beta receptors (TGFBR1 and 2).Case presentationWe report a 7-year-old Japanese boy with Loeys–Dietz syndrome who carried a novel, de novo missense mutation in TGFBR2 (c.1142g > c, R381P). He showed dysmorphic faces and skeletal malformations that were typical in previous cases with Loeys-Dietz syndrome. The cardiac studies disclosed the presence of markedly dilated aortic root and patent ductus aorteriosus. The cranial magnetic resonance imaging (MRI) and angiography (MRA) detected the tortuous appearances of the bilateral middle cerebral and carotid arteries.ConclusionThis study depicts the systemic vascular phenotypes of a child with Loeys–Dietz syndrome that were caused by a novel heterozygous mutation of TGFR2. A large cohort with serial imaging studies for vascular phenotypes will be useful for delineating the genotype-phenotype correlations of Loeys–Dietz syndrome.

Histo-blood group gene polymorphisms as potential genetic modifiers of the development of coronary artery lesions in patients with Kawasaki disease

Abnormal immunological responses to certain microbial agents may play a crucial role in the pathogenesis of Kawasaki disease (KD). The association studies between histo‐blood group genes (Lewis and ABO blood types) and various types of infectious diseases or vasculopathy have been carried out based on the fact that glycosylated antigens could directly mediate microbial infections. We attempted to clarify the role of blood type antigens in the development of KD and coronary artery lesions in KD patients. The subjects included 164 KD patients enrolled from 1998 to 2003 (1st group), 232 patients from 2004 to 2009 (2nd group), and 223 healthy children and 118 patients with growth hormone deficiency as controls. The genotyping of the FUT2 and FUT3 genes, and ABO genotypes, was determined with the TaqMan SNP assay and allele‐specific polymerase chain reaction. No significant differences were observed in the genotypes and allele frequencies of the FUT2 and FUT3 genes between the groups. The frequency of the BB blood genotype was significantly higher in KD patients with coronary artery lesions in the 1st and 2nd groups than in the controls (17% and 14% vs. 5%, P = 0.0020). This is the first report to investigate the roles of ABO and Lewis blood types in the development of KD, and in the formation of coronary artery lesions in KD patients. These data suggest that the ABO blood type may play a role in the development of coronary artery lesions in KD patients.

Recurrent atrial fibrillation after high-dose methylprednisolone therapy in a girl with lupus-associated hemophagocytic syndrome

Hemophagocytic syndrome (HPS) is a serious complication of systemic lupus erythematosus (SLE). A 15-year-old female with lupus-nephritis developed HPS. Bone marrow study showed florid thrombophagocytosis. There was no associated infection. High-dose methylprednisolone therapy ameliorated HPS. However, atrial fibrillation (Af) repeated after the infusion and required direct-current cardioversion. No underlying diseases were found in the heart and endocrine system. Chest roentgenogram and echocardiography were normal. Electrocardiogram showed slightly prolonged PR interval in sinus rhythm. Af occurred at high circulating levels of interferon-γ and interleukin (IL)-10, but not IL-6, IL-2, tumor necrosis factor-α, C-reactive protein or catecholamines. This is the first observation that high-dose corticosteroid induced Af in a case of lupus-HPS. Af is unusual in SLE children without cardiac disease, while conduction defect occurs associated with lupus-myocarditis. Lupus-HPS may be an aggressive SLE subset with cardiac involvement. High-dose corticosteroid infusion controls lupus activity, but could disclose the cardiac stress in lupus-HPS patients.

One-stop shop assessment for atrial septal defect closure using 256-slice coronary CT angiography.

ObjectivesTo investigate the feasibility and accuracy of measurement of the pulmonary to systemic blood flow ratio (Qp/Qs) and defect and rim sizes in secundum atrial septal defects (ASDs) using 256-slice CT, compared to the reference transoesophageal echocardiography (TEE) and right heart catheterization (RHC) measurements.MethodsTwenty-three consecutive adult patients with secundum ASDs who underwent retrospective ECG-gated coronary CT angiography (CCTA), TEE and RHC were enrolled in this study. Right ventricular (RV) and left ventricular (LV) stroke volumes (SV) were calculated by biventricular volumetry of CCTA. Qp/Qs-CT was defined as RVSV/LVSV. The sizes of the defect and rim were measured by multi-planar reconstruction CT images. Correlations between Qp/Qs-CT and Qp/Qs–RHC and between the defect diameter obtained by CT and TEE were analyzed by Pearson’s coefficient analysis. Rim sizes by CT and TEE were compared by paired t-test.ResultsQp/Qs-CT was significantly correlated with Qp/Qs-RHC (r = 0.83, p < 0.0001), and the defect diameter by CT was significantly correlated with that by TEE (r = 0.95, p < 0.0001). There was no significant difference between CT and TEE in measurements of rim size.Conclusions256-slice CCTA allows measuring Qp/Qs and size of defects and rims in patients with secundum ASDs, accomplishing pretreatment evaluation non-invasively and comprehensively.Key Points• Quantification of left-to-right shunting can be performed reliably and accurately by CT.• The sizes of defects and rims can be measured accurately using 256-slice CT.• 256-slice CT permits pretreatment evaluation of ASD non-invasively and comprehensively.