Aetiological Significance of Infectious Stimuli in Kawasaki Disease.

Kawasaki disease (KD) is a pediatric vasculitis syndrome that is often involves coronary artery lesions (e. g., coronary artery aneurysms). Although its causal factors and entire pathogenesis remain elusive, the available evidence indicates that the pathogenesis of KD is closely associated with dysregulation of immune responses to various viruses or microbes. In this short review, we address several essential aspects of the etiology of KD with respect to the immune response to infectious stimuli: 1) the role of viral infections, 2) the role of bacterial infections and the superantigen hypothesis, 3) involvement of innate immune response including pathogens/microbe-associated molecular patterns and complement pathways, and 4) the influence of genetic background on the response to infectious stimuli. Based on the clinical and experimental evidence, we discuss the possibility that a wide range of microbes and viruses could cause KD through common and distinct immune processes.

Emergence and Characterization of Acute Coronary Syndrome in Adults After Confirmed or Missed History of Kawasaki Disease in Japan: A Japanese Nationwide Survey.

Background: Acute coronary syndrome (ACS), which is emerging in adults long after confirmed (followed-up or lost-to-follow), or missed Kawasaki disease (KD), is poorly characterized. Methods and Results: A Japanese retrospective nationwide hospital-based questionnaire survey of ACS during 2000-09 was conducted to characterize such patients. Among a total of 67 patients (median age 35, male 76%) recruited, low conventional coronary risks (≤1/6) was noted in 75%, a diagnosis of ST-elevation and myocardial infarction or cardiac arrest in 66%, medication before ACS in 22% (warfarin in 4%), and no prior history of acute myocardial infarction in 94%. One-month mortality was 19%. KD diagnosis was made in 32 during acute illness (Group A), in which 17 were lost to follow, and retrospectively in the other 35 from coronary imaging at ACS (Group B). Group A developed ACS at lower coronary risks (≤2/5 in 87 vs. 65% in group B, p = 0.043) at a younger age (26.5 vs. 40 yo, p < 0.001). In group A, followed-up patients developed ACS under medication before ACS (87 vs. 0% in lost-to-follow patients, p < 0.001) for giant aneurysm in culprit lesions (69 vs. 29%, p = 0.030). One-month mortality was comparable between groups A and B, and between patients followed-up and lost-to-follow in group A. The culprit lesion in group A was characterized by the association of an aneurysm ≥6 mm in acute KD (100%), lack of significant stenosis (61%) or giant aneurysm (50%) in the long-term (median interval 16 y), and the presence of intravascular ultrasound-derived calcification at ACS (86%). Conclusions: The present retrospective nationwide questionnaire survey demonstrated nationwide emergence of initial ACS in young adults at low coronary risks, who are followed-up or lost-to-follow after confirmed KD and initial coronary aneurysms ≥6 mm.

Acute encephalopathy with biphasic seizures and late reduced diffusion associated with Streptococcus sanguinis sepsis.

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) develops in association with systemic as well as central nervous system (CNS) viral or bacterial infections. AESD is most often noted with influenza or human herpesvirus 6 infection in previously healthy infants. However, AESD has also been reported in an infant with developmental retardation and in a mentally and motor-disabled adolescent. Here, we report the case of a 4- year-old female with significant development delay due to spinal muscular atrophy, who developed AESD during Streptococcus sanguinis sepsis with no apparent CNS infection. Although the patient had extremely high serum procalcitonin (45.84 ng/mL, reference; <0.4) on admission indicating a poor prognosis, she was successfully managed for sepsis and AESD.

Association of Severity of Coronary Artery Aneurysms in Patients With Kawasaki Disease and Risk of Later Coronary Events.

Importance: Few studies with sufficient statistical power have shown the association of the z score of the coronary arterial internal diameter with coronary events (CE) in patients with Kawasaki disease (KD) with coronary artery aneurysms (CAA). Objective: To clarify the association of the z score with time-dependent CE occurrence in patients with KD with CAA. Design, Setting, and Participants: This multicenter, collaborative retrospective cohort study of 44 participating institutions included 1006 patients with KD younger than 19 years who received a coronary angiography between 1992 and 2011. Main Outcomes and Measures: The time-dependent occurrence of CE, including thrombosis, stenosis, obstruction, acute ischemic events, and coronary interventions, was analyzed for small (z score, <5), medium (z score, ≥5 to <10; actual internal diameter, <8 mm), and large (z score, ≥10 or ≥8 mm) CAA by the Kaplan-Meier method. The Cox proportional hazard regression model was used to identify risk factors for CE after adjusting for age, sex, size, morphology, number of CAA, resistance to initial intravenous immunoglobulin (IVIG) therapy, and antithrombotic medications. Results: Of 1006 patients, 714 (71%) were male, 341 (34%) received a diagnosis before age 1 year, 501 (50%) received a diagnosis between age 1 and 5 years, and 157 (16%) received a diagnosis at age 5 years or older. The 10-year event-free survival rate for CE was 100%, 94%, and 52% in men (P < .001) and 100%, 100%, and 75% in women (P < .001) for small, medium, and large CAA, respectively. The CE-free rate was 100%, 96%, and 79% in patients who were not resistant to IVIG therapy (P < .001) and 100%, 96%, and 51% in patients who were resistant to IVIG therapy (P < .001), respectively. Cox regression analysis revealed that large CAA (hazard ratio, 8.9; 95% CI, 5.1-15.4), male sex (hazard ratio, 2.8; 95% CI, 1.7-4.8), and resistance to IVIG therapy (hazard ratio, 2.2; 95% CI, 1.4-3.6) were significantly associated with CE. Conclusions and Relevance: Classification using the internal diameter z score is useful for assessing the severity of CAA in relation to the time-dependent occurrence of CE and associated factors in patients with KD. Careful management of CE is necessary for all patients with KD with CAA, especially men and IVIG-resistant patients with a large CAA.

Urinary liver-type fatty acid-binding protein in pediatric nephrotic syndrome and tubular dysfunction.

BACKGROUND: Urinary liver-type fatty acid-binding protein (uL-FABP) has recently been identified as a biomarker for kidney injury. uL-FABP excretion in pediatric relapsing nephrotic syndrome and tubular dysfunction, however, has not been reported previously. METHODS: We measured uL-FABP level in children with steroid-sensitive nephrotic syndrome (SSNS), in those with tubular dysfunction, and in control subjects. RESULTS: uL-FABP was markedly increased in relapsing SSNS (median, 30.3 µg/gCr; range, 12.6-171.0 µg/gCr; n = 13), and also in the tubular dysfunction group (median, 164.8 µg/gCr; range, 41.6-834.5 µg/gCr; n = 7), compared with the control subjects (median, 3.0 µg/gCr; range, 1.1-13.9 µg/gCr; n = 21). uL-FABP level was significantly correlated with urinary protein excretion in the SSNS group, and in the total group. Additionally, in the SSNS group, elevated uL-FABP in the relapsing stage returned to a level similar to that in the control group on remission of NS. In the tubular dysfunction group, uL-FABP was significantly correlated with urinary ß2-microglobulin. CONCLUSION: Urinary protein amount, and the ability of the proximal tubules to reabsorb low-molecular-weight proteins, should also be considered when evaluating the clinical significance of uL-FABP as a biomarker for kidney injury in children.

Health-care transition after Kawasaki disease in patients with coronary artery lesion.

BACKGROUND: Discussion of health-care transition (HCT) for adults with a childhood history of coronary artery lesions (CAL) after Kawasaki disease (KD) is important. A nationwide questionnaire survey was performed with support by the Japanese Society of Kawasaki Disease. The purpose of this study was to clarify the reality of HCT and loss to follow-up in patients with CAL after KD. METHODS: The survey was emailed to 48 members of the Japanese Society of Kawasaki Disease from May to July 2014. RESULTS: Forty surveys were collected, giving a response rate of 83.3%. Sixty-five percent of the respondents belonged to a university hospital. Approximately 90% of the respondents dealt with patients who needed HCT, and 55% had patients who completed HCT. Approximately 70% of the respondents considered that pediatricians should continue sharing HCT information with cardiologists. More than 95% of the respondents had a favorable or average impression of HCT care provided by cardiologists. The percentage of respondents who had loss to follow up for HCT was >40%. CONCLUSION: Adult cardiologists began managing patients with CAL after KD in more than half of the institutes in this study. Pediatricians should construct a support program for better management of these patients and for cooperation with cardiologists to prevent loss to follow up.

Nationwide Survey of Patients With Giant Coronary Aneurysm Secondary to Kawasaki Disease 1999-2010 in Japan.

BACKGROUND: Giant coronary aneurysm is the most severe sequela in Kawasaki disease, occurring in approximately 0.2% of patients in Japan. Regression is rare, while myocardial infarction (MI) and sudden death are relatively common. Herein, we reviewed patients with giant coronary aneurysm in a 10-year period.Methods and Results:A nationwide questionnaire survey was conducted based on a national epidemiological database from 1999 to 2010. We identified 355 giant coronary aneurysm patients, of whom 209 were analyzed. The 5- and 10-year total cardiac event-free rates were 0.72 and 0.68, respectively. Twelve patients died, and MI was observed in 32 patients (18.1%). Five and 6 deaths were due to coronary rupture and MI, respectively. All ruptures occurred within 1 month of onset, while most MI occurred within 18 months. There was no death beyond 2 years. Aneurysm size was significantly related to the occurrence of MI in both the right and left coronary arteries. At the time of writing, 55% of patients had no exercise limitations. And including patients who cannot perform strenuous exercises, 81% of patients were leading ordinary lives. CONCLUSIONS: Severe cardiac events are likely to occur within 2 years from onset of Kawasaki disease, while no deaths occurred beyond this time. Hence, careful monitoring is needed especially for the first 2 years. Most patients with giant coronary aneurysms can lead ordinary lives with appropriate management.

The Application of a Modified d-ROMs Test for Measurement of Oxidative Stress and Oxidized High-Density Lipoprotein.

Reactive oxygen species (ROS) are involved in the initiation and progression of atherosclerosis. ROS-derived hydroperoxides, as an indicator of ROS production, have been measured by using the diacron reactive oxygen metabolites (d-ROMs) test, which requires iron-containing transferrin in the reaction mixture. In this study we developed a modified d-ROMs test, termed the Fe-ROMs test, where iron ions were exogenously added to the reaction mixture. This modification is expected to exclude the assay variation that comes from different blood iron levels in individuals. In addition, this Fe-ROMs test was helpful for determining the class of plasma lipoproteins that are hydroperoxidized. Low-density lipoprotein/very low-density lipoprotein (LDL/VLDL) and high-density lipoprotein (HDL) were purified by use of an LDL/VLDL purification kit and the dextran sulfate-Mg2+ precipitation method, respectively; their hydroperoxide contents were assessed by performing the Fe-ROMs test. The majority of the hydroperoxides were detected only in the HDL fraction, not in the LDL/VLDL. Further detailed analysis of HDLs by size-exclusion high-performance liquid chromatography revealed that the hydroperoxide-containing molecules were small-sized HDLs. Because HDL was shown to be the principal vehicle for the plasma hydroperoxides, this Fe-ROMs test is a beneficial method for the assessment of oxidized-HDL levels. Indeed, Fe-ROMs levels were strongly associated with the levels of oxidized HDL, which were determined by performing the malondialdehyde-modified HDL enzyme immunoassay. In conclusion, the Fe-ROMs test using plasma itself or the HDL fraction after dextran sulfate-Mg2+ precipitation is useful to assess the functionality of HDL, because the oxidation of HDL impairs its antiatherogenic capacity.

Non-receptor type, proline-rich protein tyrosine kinase 2 (Pyk2) is a possible therapeutic target for Kawasaki disease.

Kawasaki disease (KD) is a paediatric vasculitis whose pathogenesis remains unclear. Based on experimental studies using a mouse model for KD, we report here that proline-rich protein tyrosine kinase 2 (Pyk2) plays a critical role in the onset of KD-like murine vasculitis. The mouse model for KD was prepared by administrating a Candida albicans water-soluble fraction (CAWS). Unlike CAWS-treated WT mice, CAWS-treated Pyk2-Knockout (Pyk2-KO) mice did not develop apparent vasculitis. A sustained increase in MIG/CXCL9 and IP-10/CXCL10, both of which have potent angiostatic activity, was observed in CAWS-treated Pyk2-KO mice. CAWS-induced activation of STAT3, which negatively regulates the expression of these chemokines, was also attenuated in macrophages derived from Pyk2-KO mice. The present study suggests that defects in Pyk2 suppress KD-like experimental vasculitis, presumably through CXCL9- and CXCL10-dependent interference with neo-angiogenesis. Since Pyk2-KO mice show no life-threatening phenotype, Pyk2 may be a promising therapeutic molecular target for KD.

Oxidative stress and Kawasaki disease: how is oxidative stress involved from the acute stage to the chronic stage?

Inflammation and oxidative stress are closely related. Further, oxidative stress plays an important role in the pathology of inflammation-based Kawasaki disease. An excessive in vivo production of reactive oxygen species increases oxidative stress in the body, which triggers an endless vicious spiral of inflammation reactions and reactive oxygen metabolites. This presumably forms diffuse vasculitis in the acute phase. Acute inflammation and oxidative stress can be rapidly controlled by treatments; however, they may remain for a long time. This has recently been identified as a problem in the chronic phase of Kawasaki disease. Generally, the presence of vascular inflammation and oxidative stress impairs blood vessels, leading to the onset of atherosclerosis, which is a widely recognized risk. The current discussion focuses on whether the same is valid for blood vessels in the chronic phase of Kawasaki disease.

Transcriptional Analysis of Intravenous Immunoglobulin Resistance in Kawasaki Disease Using an Induced Pluripotent Stem Cell Disease Model.

BACKGROUND: Approximately 10-20% of Kawasaki disease (KD) patients are resistant to intravenous immunoglobulin (IVIG) treatment. Further, these patients are at a particularly high risk of having coronary artery abnormalities. The mechanisms of IVIG resistance in KD have been analyzed using patient leukocytes, but not patient vascular endothelial cells (ECs). The present study clarifies the mechanisms of IVIG resistance in KD using an induced pluripotent stem cell (iPSC) disease model.Methods and Results:Dermal fibroblasts or peripheral blood mononuclear cells from 2 IVIG-resistant and 2 IVIG-responsive KD patients were reprogrammed by the episomal vector-mediated transduction of 6 reprogramming factors. KD patient-derived iPSCs were differentiated into ECs (iPSC-ECs). The gene expression profiles of iPSC-ECs generated from IVIG-resistant and IVIG-responsive KD patients were compared by RNA-sequencing analyses. We found that the expression ofCXCL12was significantly upregulated in iPSC-ECs from IVIG-resistant KD patients. Additionally, Gene Set Enrichment Analysis (GSEA) revealed that gene sets involved in interleukin (IL)-6 signaling were also upregulated. CONCLUSIONS: The first iPSC-based model for KD is reported here. Our mechanistic analyses suggest thatCXCL12, which plays a role in leukocyte transmigration, is a key molecule candidate for IVIG resistance and KD severity. They also indicate that an upregulation of IL-6-related genes may be involved in this pathogenesis.

A New Z Score Curve of the Coronary Arterial Internal Diameter Using the Lambda-Mu-Sigma Method in a Pediatric Population.

BACKGROUND: Several coronary artery Z score models have been developed. However, a Z score model derived by the lambda-mu-sigma (LMS) method has not been established. METHODS: Echocardiographic measurements of the proximal right coronary artery, left main coronary artery, proximal left anterior descending coronary artery, and proximal left circumflex artery were prospectively collected in 3,851 healthy children ≤18 years of age and divided into developmental and validation data sets. In the developmental data set, smooth curves were fitted for each coronary artery using linear, logarithmic, square-root, and LMS methods for both sexes. The relative goodness of fit of these models was compared using the Bayesian information criterion. The best-fitting model was tested for reproducibility using the validation data set. The goodness of fit of the selected model was visually compared with that of the previously reported regression models using a Q-Q plot. RESULTS: Because the internal diameter of each coronary artery was not similar between sexes, sex-specific Z score models were developed. The LMS model with body surface area as the independent variable showed the best goodness of fit; therefore, the internal diameter of each coronary artery was transformed into a sex-specific Z score on the basis of body surface area using the LMS method. In the validation data set, a Q-Q plot of each model indicated that the distribution of Z scores in the LMS models was closer to the normal distribution compared with previously reported regression models. Finally, the final models for each coronary artery in both sexes were developed using the developmental and validation data sets. A Microsoft Excel-based Z score calculator was also created, which is freely available online (http://raise.umin.jp/zsp/calculator/). CONCLUSIONS: Novel LMS models with which to estimate the sex-specific Z score of each internal coronary artery diameter were generated and validated using a large pediatric population.

Tolerance to ischemia reperfusion injury in a congenital heart disease model.

BACKGROUND: Open heart surgery-associated ischemia/reperfusion (I/R) injury affects postoperative outcome, and a leading cause of this is lipid peroxidation. Congenital heart disease (CHD) patients, however, are less sensitive to I/R injury. Although little is known about the underlying molecular mechanisms, CHD-associated hypoxia alters the polyunsaturated fatty acid (PUFA) composition of membranes, which are the preferential targets for reactive oxygen species (ROS) generated during I/R. Here, using an animal model, we investigated the molecular mechanisms underlying I/R tolerance in CHD. METHODS: In order to reproduce I/R injury in vitro, we used a working heart perfusion model, isolated from juvenile control and CHD model rats (CHD rats), and examined the recovery of cardiac function during a period of I/R. PUFA composition of the plasma membrane was determined on gas chromatography/mass spectrometry. Oxidative stress-related cellular responses were investigated on immunoblotting, using antibodies against nuclear factor erythroid 2-related factor (Nrf-2), hemeoxygenase-1 (HO-1), and 4-hydroxy-2-hexanal (4-HHE)-modified protein. RESULTS: Ischemia/reperfusion-induced cardiac dysfunction was markedly suppressed in CHD rats, compared with the control rats. n-3/n-6 PUFA ratio was significantly increased in both the pre- and post-I/R phase in CHD rats, but not in the controls. Four-HHE-modified protein, Nrf-2, and HO-1 were significantly increased in CHD rats as well, compared with the controls. CONCLUSIONS: Following open heart surgery in CHD patients, the increased n-3/n-6 PUFA ratio may lead to the upregulation of cellular antioxidative system components through the oxidation product, 4-HHE, resulting in an increased tolerance to I/R injury.

Histopathological Characteristics of Post-inflamed Coronary Arteries in Kawasaki Disease-like Vasculitis of Rabbits.

Kawasaki disease (KD) is a systemic vasculitis in infants that develops predominantly in the coronary arteries. Despite the clinically transient nature of active inflammation in childhood albeit rare complications (e.g., coronary artery aneurysm), KD has recently been suggested to increase the incidence of ischemic heart diseases in young adulthood. However, little is known about the histopathology of the coronary artery long after development of the acute KD vasculitis. To address this, we conducted histological studies of rabbit coronary arteries in adolescent phase after induction of the KD-like vasculitis induced by horse serum administration. After a transmural infiltration of inflammatory cells in acute phase at day 7, the artery exhibited a gradual decrease in the number of inflammatory cells and thickening of the intima during the chronic phase up to day 90, where proteoglycans were distinctly accumulated in the intima with abundant involvement of α-smooth muscle actin (α-SMA)-positive cells, most of which accompanied expression of VCAM-1 and NF-κB. Distinct from classical atherosclerosis, inflammatory cells, e.g., macrophages, were barely detected during the chronic phase. These observations indicate that the KD-like coronary arteritis is followed by intimal thickening via accumulation of proteoglycans and proliferation of α-SMA-positive cells, reflecting aberrant coronary artery remodeling.

Combined Alport syndrome and Klinefelter syndrome.

To date, there have been a very limited number of case reports on combined Alport syndrome (AS) and Klinefelter syndrome (KS). We herein describe the case of a 9-month-old boy diagnosed with concomitant AS and KS. KS was detected on chromosomal analysis of the amniotic fluid, and hematuria/proteinuria was identified in urinary screening at 6 months of age. Renal biopsy indicated AS, with complete deficit of the α5 chain of type IV collagen in the glomerular basement membranes. On genetic analysis for AS, de novo homozygote mutation (c.3605-2a > c) was seen in the gene encoding α5 chain of type IV collagen (COL4A5) on the X chromosomes of maternal origin. This is the first case report of combined AS and KS diagnosed during infancy, and it indicates the need to consider the concurrent existence of these two disorders in infants with urine abnormalities, even in the absence of a family history.

Genetic mutation analysis in Japanese patients with non-syndromic congenital heart disease.

Congenital heart disease (CHD) is the most common birth defect occurring in humans and some transcriptional factors have been identified as causative. However, additional mutation analysis of these genes is necessary to develop effective diagnostic and medical treatment methods. We conducted sequence analysis of the coding regions of NKX2.5, GATA4, TBX1, TBX5, TBX20, CFC1 and ZIC3 in 111 Japanese patients with non-syndromic CHD and 9 of their relatives. All patient samples were also analyzed by multiplex ligation-dependent probe amplification using probes involved in chromosome deletion related to CHD. Five novel variations of TBX5, GATA4 and TBX20 were detected in 6 of the patients, whereas none were found in 200 controls. The TBX5 variation p.Pro108Thr, located in the T-box domain, was identified in a patient with tricuspid atresia, an exon-intron boundary variation of GATA4 (IVS4+5G>A) was detected in a Tetralogy of Fallot patient and an 8p23 microdeletion was detected in one patient with atrioventricular septal defect and psychomotor delay. A total of seven non-synonymous polymorphisms were found in the patients and controls. Accumulation of novel variations of genes involving the cardiac development may be required for better understanding of CHD.

Asymptomatic spinal arteriovenous fistula presenting only as continuous murmur.

Spinal arteriovenous fistula is extremely rare in children. Weakness and sensory disturbance in the lower extremities are the specific clinical presentations. Children, however, commonly have no subjective symptoms; in rare cases, a continuous murmur is the only physical finding. An 18-month-old boy was referred for evaluation of a continuous murmur audible at the back. He had no motor or sensory disorder; only a Levine 3/6 continuous murmur audible at the back was found. Echocardiography showed a structurally normal heart but indicated ascending continuous blood flow behind the aortic arch and dilatation of the innominate vein. We suspected spinal arteriovenous fistula, and it was visualized on computed tomography angiography. Spinal arteriovenous fistula was detected using only auscultation and echocardiography. Suspicion of this anomaly on careful auscultation and simple examination, and confirmation on detailed examination, even in the absence of motor or sensory disturbance, is important.

Coexisting Membranous Nephropathy and IgA Nephropathy.

We herein present a case of a 14-year-old boy with the histological features of coexisting membranous nephropathy (MN) and IgA nephropathy (IgAN). Asymptomatic hematuria/proteinuria was initially detected in school urinary screening, with treatments including oral corticosteroids leading to complete remission. Cases of coexisting MN and IgAN are very rare among the pediatric population; however, the overlap of these two nephropathies does not always imply a deleterious clinical outcome in pediatric cases.

IgA nephropathy in a girl with mitochondrial disease.

Mitochondrial renal disease is one of the important causes of end-stage renal disease in children and its incidence may be underestimated. We here describe the case of a 13-year-old girl who was diagnosed with mitochondrial disease (MD) accompanied by IgA nephropathy (IgAN). She presented with persistent proteinuria, short stature, and hearing defect, and her younger sister had the same symptoms. Renal biopsy indicated mild focal segmental mesangial proliferation with dominant mesangial IgA deposition on immunofluorescence. Electron microscopy showed marked proliferation of abnormal mitochondria in the proximal tubular cells. Enzyme activity of the mitochondrial respiratory chain complex I and IV in cultured skin fibroblasts was significantly decreased. This case indicated the possible co-occurrence of IgAN and MD. Underlying MD should be considered in patients with urine abnormalities, especially in those with multiple organ involvement.