Tomoyo Yahata

Effects of HMG-CoA reductase inhibitors on continuous post-inflammatory vascular remodeling late after Kawasaki disease

BACKGROUND In Kawasaki disease (KD), it has been clinically and experimentally reported that post-inflammatory vascular remodeling would induce the development of arteriosclerosis or early onset of atherosclerosis in the future. The effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on continuous vascular remodeling late after Kawasaki disease were clinically evaluated. PATIENTS AND METHODS We enrolled and treated a total of 11 KD patients (age range, 7-25 years) with fluvastatin (0.5-0.7 mg/kg/day) for 12 months. All of them had significant coronary aneurysmal or stenotic lesions and more than 3 of the following 5 abnormal findings: reduced %flow-mediated dilatation (%FMD), reduced urinary NOx, elevated high-sensitivity C-reactive protein (hs-CRP), reduced urinary 8-isoprostane, and elevated brachial-ankle pulse wave velocity (baPWV; control, ≤1400 cm/s). RESULTS A statistically significant improvement was observed in each biomarker after fluvastatin treatment: %FMD, from 9.29% (3.41)% to 10.55% (3.27)% (p=0.003) after 3 months; NOx/creatinine (cre), from 1.16 (0.54) µmol/mg cre to 1.30 (0.50) µmol/mg cre (p=0.038) after 12 months; baPWV, from 1175.4 (277.3) cm/s to 1031.8 (155.6) cm/s (p=0.009) after 3 months; hs-CRP, from 0.073 (0.035) mg/dl to 0.028 (0.014) mg/dl (p=0.0002) after 3 months; and 8-iso/cre, from 751.8 (241.8) pg/mg cre to 660.0 (198.5) pg/mg cre (p=0.018) after 3 months. No adverse events were clinically observed in the patients. CONCLUSIONS The results of this study suggested that HMG-CoA reductase inhibitors are useful as an alternative therapeutic strategy for stabilizing continuous post-inflammatory vascular remodeling that results in the development of arteriosclerosis late after KD or early onset of atherosclerosis in the future.

The involvement of the vasa vasorum in the development of vasculitis in animal model of Kawasaki disease.

BackgroundKawasaki Disease (KD) involves a diffuse and systemic vasculitis of unknown etiology that mainly affects infants and children. Although a considerable number of analyses of the clinical, histopathological and molecular biological details underlying the mechanism responsible for the development of coronary arterial lesions, it is still poorly understood.The purpose of this study was to analyze the state of angiogenesis, vasculogenesis and the distribution of blood vessels using an animal model of KD like vasculitis. We investigated the involvement of the vasa vasorum from the adventitia in the vascular involvement and the development of the disease state by performing sequential histopathology, scanning electron microscopy (SEM) and micro computed tomography (CT) studies using a murine model of vasculitis induced by the Candida albicans water-soluble fraction (CAWS).MethodsTo prepare the animal model of KD like vasculitis, CAWS was intraperitoneally injected into C57BL/6N mice for five consecutive days as reported by Ohno et al. We observed the changes of the vasa vasorum at the aorta and the orifices of the coronary arteries by SEM and micro CT, and also compared the neovascularization at the media and adventitia of the aorta by an immunohistochemical analysis.ResultsAs previously reported, obvious inflammation was detected two weeks after the injection of CAWS, and also intimal thickening was observed three weeks after the injection. We found that the vasa vasorum in the adventitia of the aorta was increased in the model mice. The vasa vasorum started increasing one week after the injection of CAWS, before any obvious vasculitis was microscopically detected.ConclusionThe present results indicate that the vasculitis in Kawasaki disease starts as a disorder of the vasa vasorum.

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.

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.

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.

Rapidly progressive IgA nephropathy.

A 14-year-old boy presented with macroscopic hematuria and a rapid deterioration in renal function. Percutaneous renal biopsy demonstrated severe crescentic IgA nephropathy (IgAN) with extensive (88%) glomerular crescent formation. After started intravenous administration of high-dose pulse methylprednisolone, severe nausea and general malaise accompanied by a rapid increase in Blood Urea Nitrogen (BUN) and serum creatinine levels appeared, however, the renal function ameliorated rapidly and fully recovered by following oral administration of corticosteroid. The clinical presentation of our case seems to be very remarkable compared to previously reported cases of rapidly progressive IgAN.A 14-year-old boy presented with macroscopic hematuria and a rapid deterioration in renal function. Percutaneous renal biopsy demonstrated severe crescentic IgA nephropathy (IgAN) with extensive (88%) glomerular crescent formation. After started intravenous administration of high-dose pulse methylprednisolone, severe nausea and general malaise accompanied by a rapid increase in Blood Urea Nitrogen (BUN) and serum creatinine levels appeared, however, the renal function ameliorated rapidly and fully revovered by following oral administration of corticosteroid. The clinical presentation of our case seems to be very remarkable compared to previously reported cases of rapidly progressive IgAN.

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.

EXPERIMENTAL IMMUNOHISTOCHEMICAL STUDY ON PERSISTENT VASCULAR REMODELING RELATED TO DEVELOPMENT OF ARTERIOSCLEROSIS OR ATHEROSCLEROSIS IN CHRONIC KAWASAKI DISEASE PATIENTS

Atherosclerotic coronary heart disease has recently emerged as a clinical issue among young individuals with a history of Kawasaki disease (KD), which is a systemic vasculitis unique to children. However, whether or not and how KD promotes atherosclerosis remains unclear. We hypothesized that,

Oxidative Stress in Kawasaki Disease Vasculitis

Although the underlying mechanisms by which Kawasaki disease (KD) triggers vasculitis remain unclear, certain stimuli that release inflammatory substances trigger vasculitis during its acute phase, and may continue to cause vascular deterioration in subsequent phases of this disease. Cellular systems responsible for the generation and scavenging of reactive oxygen species (ROS) are clearly involved in the pathogenesis of KD vasculitis. In this manuscript, we discuss studies that illuminate the role of exudative stress in vascular pathology occurring during the acute phase, the interval following the acute phase, and the chronic phase of KD. We also discuss appropriate therapies and the potential role of antioxidant therapy in the treatment and prevention of KD vasculitis. We conclude there is no clear evidence that current antioxidant therapy can prevent the onset of arteriosclerosis and that administering current antioxidant therapy to children with a prior history of KD may not immediately improve prognosis. Future prospects should include research on specifically targeted antioxidant treatments and the development of reliable biomarkers for assessing vascular oxidative stress.

Oxidative Stress in Kawasaki Disease

Because inflammation and oxidative stress are closely related, oxidative stress cannot be ignored when considering pathologic conditions associated with inflammation-based Kawasaki disease (KD). KD pathogenesis is triggered by certain unknown infectious factors that activate one or multiple inflammation pathways via intricately intertwined cytokine cascades. Overproduction of reactive oxygen species from activated inflammation pathways increases oxidative stress in the body and results in an endless vicious cycle between inflammation reactions and reactive oxygen, which presumably underlies the diffuse vasculitis formed during acute KD. Although vascular inflammation and oxidative stress can be rapidly suppressed by treatment during the acute phase, they may persist in various forms for a long time. This has recently been identified as a concern in late KD. Generally, the presence of vascular inflammation and oxidative stress impairs blood vessels, leading to atherosclerosis onset, a widely recognized risk (Li et al., Atherosclerosis 237(1):208–219, 2014). This chapter will focus on determining whether the same is valid for blood vessels in late KD.