Matrix metalloproteinase haplotypes associated with coronary artery aneurysm formation in patients with Kawasaki disease

Pharmacogenomics of coronary artery response to intravenous gamma globulin in kawasaki disease

Kawasaki disease (KD) is a multisystem inflammatory illness of infants and young children that can result in acute vasculitis. The mechanism of coronary artery aneurysms (CAA) in KD despite intravenous gamma globulin (IVIG) treatment is not known. We performed a Whole Genome Sequencing (WGS) association analysis in a racially diverse cohort of KD patients treated with IVIG, both using AHA guidelines. We defined coronary aneurysm (CAA) (N = 234) as coronary z ≥ 2.5 and large coronary aneurysm (CAA/L) (N = 92) as z ≥ 5.0. We conducted logistic regression models to examine the association of genetic variants with CAA/L during acute KD and with persistence >6 weeks using an additive model between cases and 238 controls with no CAA. We adjusted for age, gender and three principal components of genetic ancestry. The top significant variants associated with CAA/L were in the intergenic regions (rs62154092 p < 6.32E-08 most significant). Variants in SMAT4, LOC100127, PTPRD, TCAF2 and KLRC2 were the most significant non-intergenic SNPs. Functional mapping and annotation (FUMA) analysis identified 12 genomic risk loci with eQTL or chromatin interactions mapped to 48 genes. Of these NDUFA5 has been implicated in KD CAA and MICU and ZMAT4 has potential functional implications. Genetic risk score using these 12 genomic risk loci yielded an area under the receiver operating characteristic curve (AUC) of 0.86. This pharmacogenomics study provides insights into the pathogenesis of CAA/L in IVIG-treated KD and shows that genomics can help define the cause of CAA/L to guide management and improve risk stratification of KD patients.

Pharmacogenomics of Coronary Artery Response to Intravenous Gamma Globulin in Kawasaki Disease

Background

Kawasaki disease (KD) is a multisystem inflammatory illness of infants and young children that can result in acute vasculitis. The pathological walls of afflicted coronary arteries show propensity for forming thrombosis and aneurysms. The mechanism of coronary artery aneurysms (CAA) despite intravenous gamma globulin (IVIG) treatment is not known.

Methods

We performed a Whole Genome Sequencing (WGS) association analysis in a racially diverse cohort of KD patients treated with IVIG, both using AHA guidelines. We defined coronary aneurysm (CAA) (N = 234) as coronary z>2.5 and large coronary aneurysm (CAA/L) (N = 92) as z>5.0. We conducted logistic regression models to examine the association of genetic variants with CAA/L during acute KD and with persistence >6 weeks using an additive model between cases and 238 controls with no CAA. We adjusted for age, gender and three principal components of genetic ancestry. We performed functional mapping and annotation (FUMA) analysis and further assessed the predictive risk score of genomic risk loci using the area under the receiver operating characteristic curve (AUC).

Results

The top significant variants associated with CAA/L were in the intergenic regions (rs62154092 p<6.32E-08 most significant). Variants in SMAT4, LOC100127 , PTPRD, TCAF2 and KLRC2 were the most significant non-intergenic SNPs. FUMA identified 12 genomic risk loci with eQTL or chromatin interactions mapped to 48 genes. Of these NDUFA5 has been implicated in KD CAA and MICU and ZMAT4 has potential functional implications. Genetic risk score using these 12 genomic risk loci yielded an AUC of 0.86.

Conclusions

This pharmacogenomics study provides insights into the pathogenesis of CAA/L in IVIG-treated KD patients. We have identified multiple novel SNPs associated with CAA/L and related genes with potential functional implications. The study shows that genomics can help define the cause of CAA/L to guide management and improve risk stratification of KD patients.

Bioinformatic analysis of underlying mechanisms of Kawasaki disease via Weighted Gene Correlation Network Analysis (WGCNA) and the Least Absolute Shrinkage and Selection Operator method (LASSO) regression model

BACKGROUND

Kawasaki disease (KD) is a febrile systemic vasculitis involvingchildren younger than five years old. However, the specific biomarkers and precise mechanisms of this disease are not fully understood, which can delay the best treatment time, hence, this study aimed to detect the potential biomarkers and pathophysiological process of KD through bioinformatic analysis.

METHODS

The Gene Expression Omnibus database (GEO) was the source of the RNA sequencing data from KD patients. Differential expressed genes (DEGs) were screened between KD patients and healthy controls (HCs) with the "limma" R package. Weighted gene correlation network analysis (WGCNA) was performed to discover the most corresponding module and hub genes of KD. The node genes were obtained by the combination of the least absolute shrinkage and selection operator (LASSO) regression model with the top 5 genes from five algorithms in CytoHubba, which were further validated with the receiver operating characteristic curve (ROC curve). CIBERSORTx was employed to discover the constitution of immune cells in KDs and HCs. Functional enrichment analysis was performed to understand the biological implications of the modular genes. Finally, competing endogenous RNAs (ceRNA) networks of node genes were predicted using online databases.

RESULTS

A total of 267 DEGs were analyzed between 153 KD patients and 92 HCs in the training set, spanning two modules according to WGCNA. The turquoise module was identified as the hub module, which was mainly enriched in cell activation involved in immune response, myeloid leukocyte activation, myeloid leukocyte mediated immunity, secretion and leukocyte mediated immunity biological processes; included type II diabetes mellitus, nicotinate and nicotinamide metabolism, O-glycan biosynthesis, glycerolipid and glutathione metabolism pathways. The node genes included ADM, ALPL, HK3, MMP9 and S100A12, and there was good performance in the validation studies. Immune cell infiltration analysis revealed that gamma delta T cells, monocytes, M0 macrophage, activated dendritic cells, activated mast cells and neutrophils were elevated in KD patients. Regarding the ceRNA networks, three intact networks were constructed: NEAT1/NORAD/XIST-hsa-miR-524-5p-ADM, NEAT1/NORAD/XIST-hsa-miR-204-5p-ALPL, NEAT1/NORAD/XIST-hsa-miR-524-5p/hsa-miR-204-5p-MMP9.

CONCLUSION

To conclude, the five-gene signature and three ceRNA networks constructed in our study are of great value in the early diagnosis of KD and might help to elucidate our understanding of KD at the RNA regulatory level.

Updated Genome-Wide Association Study of Intracranial Aneurysms by Genotype Correction and Imputation in Koreans

OBJECTIVE

Compared to European, Japanese, and Chinese populations, genetic studies on intracranial aneurysms (IAs) in Koreans are lacking. We conducted an updated genome-wide association study (GWAS) to more accurately identify candidate variations predicting IA by genotype correction and imputation than in the first Korean GWAS.

METHODS

We performed a high-throughput imputation of single-nucleotide polymorphisms (SNPs) and genotype missing values for 250 IA and 296 controls. Out of a total of 7,333,746 sites with an imputation R² score of ≥0.5, 6,105,212 SNPs were analyzed. A high-throughput GWAS was performed after adjusting for clinical variables and 4 principal component analysis values.

RESULTS

A total of 39 SNPs reached a significant genome-wide threshold (P < 5 × 10^-8). After pruning by pairwise linkage disequilibrium (r² < 0.8), 11 SNPs were consistently associated with IA. Six tagging SNPs, including rs3120004, rs1851347, rs1522095, rs7779989, rs12935558, rs3826442, and rs2440154, showed strong linkage disequilibrium tower tagging haplotype structures. Among them, rs3120004 tagged a large and strong haplotype structure between LOC440704 and RGS18 genes in 1q31.2 (odds ratio, 2.34; 95% confidence interval, 1.74-3.14; P = 1.4 × 10^-8). The rs2440154 (SLC47A1, 17p11.2) SNP increased the risk of IA most significantly (odds ratio, 2.90; 95% confidence interval, 2.07-4.08; P = 8.2 × 10^-10). The region encompassing rs3826442 (MYH13, 17p13.1) showed a high recombination rate of approximately 70 cM/Mbp.

CONCLUSIONS

Our updated GWAS using high-throughput imputation approaches can be an informative milestone in understanding IA formation via susceptibility loci in this stage before large-scale genome-wide association meta-analysis.

Identification of novel locus associated with coronary artery aneurysms and validation of loci for susceptibility to Kawasaki disease

Kawasaki disease (KD) is a paediatric vasculitis associated with coronary artery aneurysms (CAA). Genetic variants influencing susceptibility to KD have been previously identified, but no risk alleles have been validated that influence CAA formation. We conducted a genome-wide association study (GWAS) for CAA in KD patients of European descent with 200 cases and 276 controls. A second GWAS for susceptibility pooled KD cases with healthy paediatric controls from vaccine trials in the UK (n = 1609). Logistic regression mixed models were used for both GWASs. The susceptibility GWAS was meta-analysed with 400 KD cases and 6101 controls from a previous European GWAS, these results were further meta-analysed with Japanese GWASs at two putative loci. The CAA GWAS identified an intergenic region of chromosome 20q13 with multiple SNVs showing genome-wide significance. The risk allele of the most associated SNV (rs6017006) was present in 13% of cases and 4% of controls; in East Asian 1000 Genomes data, the allele was absent or rare. Susceptibility GWAS with meta-analysis with previously published European data identified two previously associated loci (ITPKC and FCGR2A). Further meta-analysis with Japanese GWAS summary data from the CASP3 and FAM167A genomic regions validated these loci in Europeans showing consistent effects of the top SNVs in both populations. We identified a novel locus for CAA in KD patients of European descent. The results suggest that different genes determine susceptibility to KD and development of CAA and future work should focus on the function of the intergenic region on chromosome 20q13.

Identification of Key Genes and Underlying Mechanisms in Acute Kawasaki Disease Based on Bioinformatics Analysis

Background

Kawasaki disease (KD) is a systemic vasculitis that predominantly occurs in children, but the pathogenesis of KD remains unclear. Here, we explored key genes and underlying mechanisms potentially involved in KD using bioinformatic analyses.

Material/Methods

The shared differentially expressed genes (DEGs) in KD compared to control samples were identified using the microarray data from the Gene Expression Omnibus Series (GSE) 18606, GSE68004, and GSE73461. Analyses of the functional annotation, protein-protein interaction (PPI) network, microRNA-target DEGs regulatory network, and immune cell infiltration were performed. The expression of hub genes before and after intravenous immunoglobulin (IVIG) treatment in KD was further verified using GSE16797.

Results

A total of 195 shared DEGs (164 upregulated and 31 downregulated genes) were identified between KD and healthy controls. These shared DEGs were mainly enriched in immune and inflammatory responses. Ten upregulated hub genes (ITGAX, SPI1, LILRB2, MMP9, S100A12, C3AR1, RETN, MAPK14, TLR5, MYD88) and the most significant module were identified in the PPI network. There were 309 regulatory relationships detected within 70 predicted microRNAs and 193 target DEGs. The immune cell infiltration analysis showed that monocytes, neutrophils, activated mast cells, and activated natural killer cells had relatively high proportions and were significantly more infiltrated in KD samples. Six hub genes of ITGAX, LILRB2, C3AR1, MAPK14, TLR5, and MYD88 were markedly downregulated after IVIG treatment for KD.

Conclusions

Our study identified the candidate genes and associated molecules that may be related to the KD process, and provided new insights into potential mechanisms and therapeutic targets for KD.

Kawasaki disease: pathophysiology and insights from mouse models

Kawasaki disease is an acute febrile illness and systemic vasculitis of unknown aetiology that predominantly afflicts young children, causes coronary artery aneurysms and can result in long-term cardiovascular sequelae. Kawasaki disease is the leading cause of acquired heart disease among children in the USA. Coronary artery aneurysms develop in some untreated children with Kawasaki disease, leading to ischaemic heart disease and myocardial infarction. Although intravenous immunoglobulin (IVIG) treatment reduces the risk of development of coronary artery aneurysms, some children have IVIG-resistant Kawasaki disease and are at increased risk of developing coronary artery damage. In addition, the lack of specific diagnostic tests and biomarkers for Kawasaki disease make early diagnosis and treatment challenging. The use of experimental mouse models of Kawasaki disease vasculitis has considerably improved our understanding of the pathology of the disease and helped characterize the cellular and molecular immune mechanisms contributing to cardiovascular complications, in turn leading to the development of innovative therapeutic approaches. Here, we outline the pathophysiology of Kawasaki disease and summarize and discuss the progress gained from experimental mouse models and their potential therapeutic translation to human disease.

This Review outlines the pathophysiology of Kawasaki disease and discusses the progress gained from experimental mouse models and their potential therapeutic translation to human disease.

Kawasaki disease is a childhood systemic vasculitis leading to the development of coronary artery aneurysms; it is the leading cause of acquired heart disease in children in developed countries.

The cause of Kawasaki disease is unknown, although it is suspected to be triggered by an unidentified infectious pathogen in genetically predisposed children.

Kawasaki disease might not be a normal immune response to an unusual environmental stimulus, but rather a genetically determined unusual and uncontrolled immune response to a common stimulus.

Although the aetiological agent in humans is unknown, mouse models of Kawasaki disease vasculitis demonstrate similar pathological features and have substantially accelerated discoveries in the field.

Genetic and transcriptomic analysis of blood samples from patients with Kawasaki disease and experimental evidence generated using mouse models have demonstrated the critical role of IL-1β in the pathogenesis of this disease and the therapeutic potential of targeting this pathway (currently under investigation in clinical trials).

A Comprehensive Update on Kawasaki Disease Vasculitis and Myocarditis

PURPOSE OF THE REVIEW

Kawasaki disease (KD) is a childhood systemic vasculitis of unknown etiology that causes coronary artery aneurysms (CAA), and if left undiagnosed can result in long-term cardiovascular complications and adult cardiac disease. Up to 20% of KD children fail to respond to IVIG, the mainstay of therapy, highlighting the need for novel therapeutic strategies. Here we review the latest findings in the field regarding specific etiology, genetic associations, and advancements in treatment strategies to prevent coronary aneurysms.

RECENT FINDINGS

Recent discoveries using the Lactobacillus casei cell wall extract (LCWE)-induced KD vasculitis mouse model have accelerated the study of KD pathophysiology and have advanced treatment strategies including clinical trials for IL-1R antagonist, Anakinra. KD remains an elusive pediatric vasculitis syndrome and is the leading cause of acquired heart disease among children in the USA and developed countries. Advancements in combination treatment for refractory KD with further understanding of novel genetic risk factors serve as a solid foundation for future research endeavors in the field.

Insights Into Coronary Artery Lesions in Kawasaki Disease

This review summarizes recent advances in understanding the development of coronary arteritis in Kawasaki disease. Kawasaki disease is the most common cause of acquired heart disease among children characterized with coronary artery abnormalities, which can cause myocardial ischemia, infarction, and even death. The pathogenic factors of Kawasaki disease and the pathological process of coronary artery disease are not clear at present, which brings challenges to the prevention and treatment of the disease. The treatment of Kawasaki disease focuses mainly on timely administration of intravenous high doses of immunoglobulin and aspirin. However, there are still some patients who do not respond well to this standard treatment, and its management remains a challenge. As a result, coronary artery lesions still occur in patients and affect their quality of life. In this review, we discuss updated research data of Kawasaki disease coronary artery lesions.

Phase I/IIa Trial of Atorvastatin in Patients with Acute Kawasaki Disease with Coronary Artery Aneurysm

OBJECTIVES

To determine the safety, tolerability, pharmacokinetics, and immunomodulatory effects of a 6-week course of atorvastatin in patients with acute Kawasaki disease with coronary artery (CA) aneurysm (CAA).

STUDY DESIGN

This was a Phase I/IIa 2-center dose-escalation study of atorvastatin (0.125-0.75 mg/kg/day) in 34 patients with Kawasaki disease (aged 2-17 years) with echocardiographic evidence of CAA. We measured levels of the brain metabolite 24(S)-hydroxycholesterol (24-OHC), serum lipids, acute-phase reactants, liver enzymes, and creatine phosphokinase; peripheral blood mononuclear cell populations; and CA internal diameter normalized for body surface area before atorvastatin treatment and at 2 and 6 weeks after initiation of atorvastatin treatment.

RESULTS

A 6-week course of up to 0.75 mg/kg/day of atorvastatin was well tolerated by the 34 subjects (median age, 5.3 years; IQR, 2.6-6.4 years), with no serious adverse events attributable to the study drug. The areas under the curve for atorvastatin and its metabolite were larger in the study subjects compared with those reported in adults, suggesting a slower rate of metabolism in children. The 24-OHC levels were similar between the atorvastatin-treated subjects and matched controls.

CONCLUSIONS

Atorvastatin was safe and well tolerated in our cohort of children with acute Kawasaki disease and CAA. A Phase III efficacy trial is warranted in this patient population, which may benefit from the known anti-inflammatory and immunomodulatory effects of this drug.

Refractory Kawasaki disease: diagnostic and management challenges

Kawasaki disease (KD), an acute, self-limiting, medium-sized arterial vasculitis, is now the most common cause of acquired heart disease in childhood in the developed world. In this review, we discuss the diagnosis of KD, predicting resistance to traditional therapy and treatment options in refractory or high-risk disease. We also highlight ongoing clinical trials and other potential avenues of research which may prove beneficial in managing children, especially those with resistant KD.

Adjunctive therapies in Kawasaki disease

Despite the administration of intravenous immunoglobulin (IVIg) at a dose of 2 g/kg, approximately 3-5% of children with acute Kawasaki disease (KD) may develop coronary artery aneurysms. IVIg-resistance, defined as recrudescence of fever more than 36 h after IVIg completion, is a risk factor for coronary artery abnormalities. Thus, several adjunctive therapies are being evaluated for use in IVIg-resistant KD patients and in patients with coronary artery abnormalities. In this review the role of some of these adjunctive therapies in treatment of children with KD is discussed.

Role of MMP-1 (-519A/G, -1607 1G/2G), MMP-3 (Lys45Glu), MMP-7 (-181A/G), and MMP-12 (-82A/G) Variants and Plasma MMP Levels on Obesity-Related Phenotypes and Microvascular Reactivity in a Tunisian Population

Aims

The impact of MMP-1 (-519A/G, -1607 1G/2G), MMP-3 Lys45Glu (A/G), MMP-7 -181A/G, and MMP-12 -82A/G variants and plasma MMP levels on obesity and microvascular reactivity in Tunisians.

Methods

Our population included 202 nonobese and 168 obese subjects. Anthropometric, biochemical, and microvascular parameters were determined according to standard protocols. PCR-RFLP and ELISA were used to determine the genetic variants and levels of MMPs, respectively.

Results

The MMP-3 45Glu (G) allele associates with higher anthropometric values and MMP-3 levels compared to AA genotype carriers (BMI (kg/m²): 30 ± 0.51 versus 27.33 ± 0.8, P = 0.004; MMP-3 levels: 7.45 (4.77–11.91) versus 5.21 (3.60–10.21) ng/ml, P = 0.006). The MMP-12 -82G allele was also associated with higher BMI values when compared to subjects carrying the AA genotype (31.41 ± 0.85 versus 28.76 ± 0.43, P < 0.001). Individuals carrying the MMP-3 45G or MMP-12 -82G variants were also associated with a higher risk for severe forms of obesity (MMP-3: OR = 1.9, P = 0.002; MMP-12: OR = 2.63, P = 0.003). Similarly, the MMP-7 -181G allele was associated with a higher MMP-7 level and an increased risk for morbid obesity when compared to AA genotype carriers (0.32 (0.31–0.60) versus 0.18 (0.17–0.24) ng/ml, P = 0.01; OR = 1.67, P = 0.02, resp.).

Conclusion

MMP-3, MMP-7, and MMP-12 polymorphisms associate with obesity risk and its severity.

Matrix Metalloproteinases, Vascular Remodeling, and Vascular Disease

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that degrade various proteins in the extracellular matrix (ECM). Typically, MMPs have a propeptide sequence, a catalytic metalloproteinase domain with catalytic zinc, a hinge region or linker peptide, and a hemopexin domain. MMPs are commonly classified on the basis of their substrates and the organization of their structural domains into collagenases, gelatinases, stromelysins, matrilysins, membrane-type (MT)-MMPs, and other MMPs. MMPs are secreted by many cells including fibroblasts, vascular smooth muscle (VSM), and leukocytes. MMPs are regulated at the level of mRNA expression and by activation through removal of the propeptide domain from their latent zymogen form. MMPs are often secreted in an inactive proMMP form, which is cleaved to the active form by various proteinases including other MMPs. MMPs degrade various protein substrates in ECM including collagen and elastin. MMPs could also influence endothelial cell function as well as VSM cell migration, proliferation, Ca²⁺ signaling, and contraction. MMPs play a role in vascular tissue remodeling during various biological processes such as angiogenesis, embryogenesis, morphogenesis, and wound repair. Alterations in specific MMPs could influence arterial remodeling and lead to various pathological disorders such as hypertension, preeclampsia, atherosclerosis, aneurysm formation, as well as excessive venous dilation and lower extremity venous disease. MMPs are often regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP ratio often determines the extent of ECM protein degradation and tissue remodeling. MMPs may serve as biomarkers and potential therapeutic targets for certain vascular disorders.

Epigenetic hypomethylation and upregulation of matrix metalloproteinase 9 in Kawasaki disease

Background

Kawasaki disease (KD) is a type of febrile coronary vasculitis occurring in children. Some researchers have suggested that changes in genetic signatures, such as matrix metalloproteinases (MMPs), are critical markers for cardiovascular diseases. This study aims to provide a comprehensive survey of global DNA methylation levels and MMP transcripts of KD patients compared to control subjects.

Materials and Methods

For chips studies, we recruited a total of 18 KD patients, prior to receiving intravenous immunoglobulin (IVIG) and at least 3 weeks after IVIG treatment, as well as 18 healthy and 18 febrile control subjects. We applied Illumina HumanMethylation450 BeadChip and Affymetrix GeneChip® Human Transcriptome Array 2.0 to evaluate their CpG markers and expression levels, respectively. Then we used a separate cohort to carry out real-time quantitative PCR validations of mRNA levels.

Results

The expressions of mRNA levels of MMP-8, -9, and -25 were significantly upregulated in KD patients compared to the healthy and febrile controls. Once KD patients underwent IVIG treatment, these MMPs considerably decreased. In particular, the methylation status of CpG sites of MMP-9 indicated a significant opposite tendency between both stages of not only the KD samples but also the controls. We also observed the mRNA level of MMP-9 to be higher in KD patients with coronary arterial lesion formation.

Conclusion

This study is the first to report epigenetic hypomethylation, an increased MMP-9 transcript, and the upregulation of MMP-9 in KD patients who had formed coronary arterial lesions.

Matrix Metalloproteinase Inhibitors as Investigational and Therapeutic Tools in Unrestrained Tissue Remodeling and Pathological Disorders

Matrix metalloproteinases (MMPs) are zinc-dependent proteolytic enzymes that degrade various proteins in the extracellular matrix (ECM). MMPs may also regulate the activity of membrane receptors and postreceptor signaling mechanisms and thereby affect cell function. The MMP family includes collagenases, gelatinases, stromelysins, matrilysins, membrane-type MMPs, and other MMPs. Inactive proMMPs are cleaved by other MMPs or proteases into active MMPs, which interact with various protein substrates in ECM and cell surface. MMPs regulate important biological processes such as vascular remodeling and angiogenesis and may be involved in the pathogenesis of cardiovascular disorders such as hypertension, atherosclerosis, and aneurysm. The role of MMPs is often assessed by measuring their mRNA expression, protein levels, and proteolytic activity using gel zymography. MMP inhibitors are also used to assess the role of MMPs in different biological processes and pathological conditions. MMP activity is regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP balance could determine the net MMP activity, ECM turnover, and tissue remodeling. Also, several synthetic MMP inhibitors have been developed. Synthetic MMP inhibitors include a large number of zinc-binding globulins (ZBGs), in addition to non-ZBGs and mechanism-based inhibitors. MMP inhibitors have been proposed as potential tools in the management of osteoarthritis, cancer, and cardiovascular disorders. However, most MMP inhibitors have broad-spectrum actions on multiple MMPs and could cause undesirable musculoskeletal side effects. Currently, doxycycline is the only MMP inhibitor approved by the Food and Drug Administration. New generation biological and synthetic MMP inhibitors may show greater MMP specificity and fewer side effects and could be useful in targeting specific MMPs, reducing unrestrained tissue remodeling, and the management of MMP-related pathological disorders.

Review: Found in Translation: International Initiatives Pursuing Interleukin-1 Blockade for Treatment of Acute Kawasaki Disease

The decision to move forward with three clinical trials of IL-1 blockade for treatment of acute Kawasaki disease is a case study in translational science. These trials were born on the one hand from transcriptome studies of host response during the acute disease coupled with animal model investigations of key immune signaling pathways and, on the other hand, out of clinical desperation to intervene in patients with severe inflammation in the setting of acute Kawasaki disease. The convergence of laboratory science and clinical observations led to the clinical trials described here and serves as a model for how such observations can be translated into new therapies.

Role of Interleukin-1 Signaling in a Mouse Model of Kawasaki Disease-Associated Abdominal Aortic Aneurysm

OBJECTIVE

Kawasaki disease (KD) is the most common cause of acquired cardiac disease in US children. In addition to coronary artery abnormalities and aneurysms, it can be associated with systemic arterial aneurysms. We evaluated the development of systemic arterial dilatation and aneurysms, including abdominal aortic aneurysm (AAA) in the Lactobacillus casei cell-wall extract (LCWE)-induced KD vasculitis mouse model.

METHODS AND RESULTS

We discovered that in addition to aortitis, coronary arteritis and myocarditis, the LCWE-induced KD mouse model is also associated with abdominal aorta dilatation and AAA, as well as renal and iliac artery aneurysms. AAA induced in KD mice was exclusively infrarenal, both fusiform and saccular, with intimal proliferation, myofibroblastic proliferation, break in the elastin layer, vascular smooth muscle cell loss, and inflammatory cell accumulation in the media and adventitia. Il1r(-/-), Il1a(-/-), and Il1b(-/-) mice were protected from KD associated AAA. Infiltrating CD11c(+) macrophages produced active caspase-1, and caspase-1 or NLRP3 deficiency inhibited AAA formation. Treatment with interleukin (IL)-1R antagonist (Anakinra), anti-IL-1α, or anti-IL-1β mAb blocked LCWE-induced AAA formation.

CONCLUSIONS

Similar to clinical KD, the LCWE-induced KD vasculitis mouse model can also be accompanied by AAA formation. Both IL-1α and IL-1β play a key role, and use of an IL-1R blocking agent that inhibits both pathways may be a promising therapeutic target not only for KD coronary arteritis, but also for the other systemic arterial aneurysms including AAA that maybe seen in severe cases of KD. The LCWE-induced vasculitis model may also represent an alternative model for AAA disease.

Regulation and involvement of matrix metalloproteinases in vascular diseases

Matrix metalloproteinases (MMPs) are a family of zinc dependent endopeptidases whose main function is to degrade and deposit structural proteins within the extracellular matrix (ECM). A dysregulation of MMPs is linked to vascular diseases. MMPs are classified into collagenases, gelatinases, membrane-type, metalloelastase, stromelysins, matrilysins, enamelysins, and unclassified subgroups. The production of MMPs is stimulated by factors such as oxidative stress, growth factors and inflammation which lead to its up- or down-regulation with subsequent ECM remodeling. Normally, excess activation of MMPs is controlled by their endogenous inhibitors, tissue inhibitors of metalloproteinases (TIMPs). An imbalance of MMPs and TIMPs has been implicated in hypertension, atherosclerotic plaque formation and instability, aortic aneurysms and varicose vein wall remodeling. Also, recent evidence suggests epigenetic regulation of some MMPs in angiogenesis and atherosclerosis. Over the years, pharmacological inhibitors of MMPs have been used to modify or prevent the development of the disease with some success. In this review, we discuss recent advances in MMP biology, and their involvement in the manifestation of vascular disease.

IL-1 Signaling Is Critically Required in Stromal Cells in Kawasaki Disease Vasculitis Mouse Model: Role of Both IL-1α and IL-1β

OBJECTIVE

Kawasaki disease (KD) is the most common cause of acute vasculitis and acquired cardiac disease among US children. We have previously shown that both TLR2/MyD88 and interleukin (IL)-1β signaling are required for the Lactobacillus casei cell wall extract-induced KD vasculitis mouse model. The objectives of this study were to investigate the cellular origins of IL-1 production, the role of CD11c(+) dendritic cells and macrophages, and the relative contribution of hematopoietic and stromal cells for IL-1 responsive cells, as well the MyD88 signaling, in Lactobacillus casei cell wall extract-induced KD mouse model of vasculitis.

APPROACH AND RESULTS

Using mouse knockout models and antibody depletion, we found that both IL-1α and IL-1β were required for Lactobacillus casei cell wall extract-induced KD. Both dendritic cells and macrophages were necessary, and we found that MyD88 signaling was required in both hematopoietic and stromal cells. However, IL-1 response and signaling were critically required in nonendothelial stromal cells, but not in hematopoietic cells.

CONCLUSIONS

Our results suggest that IL-1α and IL-1β, as well as CD11c(+) dendritic cells and macrophages, are essential for the development of KD vasculitis and coronary arteritis in this mouse model. Bone marrow chimera experiments suggest that MyD88 signaling is important in both hematopoietic and stromal cells, whereas IL-1 signaling and response are required only in stromal cells, but not in endothelial cells. Determining the role of IL-1α and IL-1β and of specific cell types in the KD vasculitis mouse model may have important implications for the design of more targeted therapies and understanding of the molecular mechanisms of KD immunopathologies.

Evaluating a novel treatment for coronary artery inflammation in acute Kawasaki disease: A Phase I/IIa trial of atorvastatin

INTRODUCTION

Since the 1980s, the primary treatment of acute Kawasaki disease (KD) has been intravenous immunoglobulin and aspirin. However, 5-10% of children with acute KD will develop coronary artery abnormalities despite treatment within the first ten days after fever onset. There is no approved adjunctive therapy to prevent progression of coronary artery damage in these patients.

AREAS COVERED

The rationale and study design of a Phase I/IIa trial of atorvastatin in children with acute KD and coronary artery inflammation is presented. The studies of host genetics and KD pathogenesis leading up to this trial are reviewed.

EXPERT OPINION

The repurposing of well-studied drugs used in the adult population is a cost-effective and efficient strategy to identify new therapies for pediatric diseases. Exploiting the anti-inflammatory, non-lipid-lowering effects of statins may open up new applications for this class of drugs for the pediatric age group.

Central Pulse Pressure and Variability in Matrix Metalloproteinases Genes and Their Inhibitors in Patients With Ischemic Heart Disease

Matrix metalloproteinases (MMPs) as well as their inhibitors (TIMPs) play a crucial role in controlling extracellular matrix turnover and have recently been associated with atherosclerosis, myocardial and vascular injury. Moreover, the genetic variability of MMP genes has been suggested to play an important role in vascular remodeling and age-related arterial stiffening. This study aims to describe associations of 14 selected polymorphisms in genes for MMPs and TIMPs with selected cardiovascular parameters (including central pulse pressure), clinical conditions and drug treatment profiles in 411 stable ischemic patients with preserved systolic function of the left ventricle. The genotyping of 14 single-nucleotide polymorphisms in 8 genes was carried out either using 5′ exonuclease (TaqMan®) reagents or by restriction analysis. Numerous associations of the investigated polymorphisms with systolic and diastolic blood pressure, maximum left ventricular end diastolic pressure and ejection fraction were observed. While some of the observed effects were found to be age-dependent, associations with clinical conditions (hypertension, diabetes mellitus, angina pectoris) were only observed in women and associations with four groups of drugs (statins, nitrates, calcium channel blockers, anti-aggregation drugs) were only observed in men. The results of this study indicate that the genetic variability of MMPs and TIMPs is an important factor which influences cardiovascular functions and may have important consequences for individual therapy customization in the future.

Update on Kawasaki disease: epidemiology, aetiology and pathogenesis

Kawasaki disease is an acute systemic vasculitis predominantly affecting young children. It is due to an abnormal host response to as yet unidentified infectious trigger(s). Kawasaki disease may cause coronary artery damage, long-term cardiovascular morbidity and occasionally mortality, especially if the diagnosis is missed or timely treatment is not given. This is the first of two updates on Kawasaki disease. Here we review recent advances in epidemiology, possible aetiologies, host susceptibility and pathogenesis of this fascinating condition.

Inference of human continental origin and admixture proportions using a highly discriminative ancestry informative 41-SNP panel

Background

Accurate determination of genetic ancestry is of high interest for many areas such as biomedical research, personal genomics and forensics. It remains an important topic in genetic association studies, as it has been shown that population stratification, if not appropriately considered, can lead to false-positive and -negative results. While large association studies typically extract ancestry information from available genome-wide SNP genotypes, many important clinical data sets on rare phenotypes and historical collections assembled before the GWAS area are in need of a feasible method (i.e., ease of genotyping, small number of markers) to infer the geographic origin and potential admixture of the study subjects. Here we report on the development, application and limitations of a small, multiplexable ancestry informative marker (AIM) panel of SNPs (or AISNP) developed specifically for this purpose.

Results

Based on worldwide populations from the HGDP, a 41-AIM AISNP panel for multiplex application with the ABI SNPlex and a subset with 31 AIMs for the Sequenome iPLEX system were selected and found to be highly informative for inferring ancestry among the seven continental regions Africa, the Middle East, Europe, Central/South Asia, East Asia, the Americas and Oceania. The panel was found to be least informative for Eurasian populations, and additional AIMs for a higher resolution are suggested. A large reference set including over 4,000 subjects collected from 120 global populations was assembled to facilitate accurate ancestry determination. We show practical applications of this AIM panel, discuss its limitations for admixed individuals and suggest ways to incorporate ancestry information into genetic association studies.

Conclusion

We demonstrated the utility of a small AISNP panel specifically developed to discern global ancestry. We believe that it will find wide application because of its feasibility and potential for a wide range of applications.

Understanding the pathogenesis of Kawasaki disease by network and pathway analysis

Kawasaki disease (KD) is a complex disease, leading to the damage of multisystems. The pathogen that triggers this sophisticated disease is still unknown since it was first reported in 1967. To increase our knowledge on the effects of genes in KD, we extracted statistically significant genes so far associated with this mysterious illness from candidate gene studies and genome-wide association studies. These genes contributed to susceptibility to KD, coronary artery lesions, resistance to initial IVIG treatment, incomplete KD, and so on. Gene ontology category and pathways were analyzed for relationships among these statistically significant genes. These genes were represented in a variety of functional categories, including immune response, inflammatory response, and cellular calcium ion homeostasis. They were mainly enriched in the pathway of immune response. We further highlighted the compelling immune pathway of NF-AT signal and leukocyte interactions combined with another transcription factor NF- κ B in the pathogenesis of KD. STRING analysis, a network analysis focusing on protein interactions, validated close contact between these genes and implied the importance of this pathway. This data will contribute to understanding pathogenesis of KD.

The Molecular Biology and Treatment of Systemic Vasculitis in Children

Primary systemic vasculitides are rare in childhood but are associated with significant morbidity and mortality. The cause of the majority of vasculitides is unknown, although it is likely that a complex interaction between environmental factors, such as infections and inherited host responses, triggers the disease and determines the vasculitis phenotype. Several genetic polymorphisms in vasculitides have now been described, which may be relevant in terms of disease predisposition or development of disease complications. Treatment regimens continue to improve with the use of different immunosuppressive medications and newer therapeutic approaches such as biologic agents. This chapter reviews recent studies shedding light on the pathogenesis of vasculitis with emphasis on molecular biology where known, and summarizes current treatment strategies. We discuss new emerging challenges particularly with respect to the long-term cardiovascular morbidity for children with systemic vasculitis and emphasize the importance of future international multicenter collaborative studies to further increase and standardize the scientific base investigating and treating childhood vasculitis.

Circulating markers of vascular injury and angiogenesis in antineutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE

To identify biomarkers that distinguish between active antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and remission in a manner superior or complementary to established markers of systemic inflammation.

METHODS

Markers of vascular injury and angiogenesis were measured before and after treatment in a large clinical trial in AAV: 163 subjects enrolled in the Rituximab in ANCA-Associated Vasculitis trial were screened for the present study. Serum levels of E-selectin, intercellular adhesion molecule 3 matrix metalloproteinase protein 1 (MMP-1), MMP-3, MMP-9, P-selectin, thrombomodulin, and vascular endothelial growth factor were measured at study screening (time of active disease) and at month 6. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels had been measured at the time of the clinical visit. The primary outcome measure was the difference in marker level between screening and month 6 among patients whose disease was in remission (Birmingham Vasculitis Activity Score for Wegener's granulomatosis [BVAS/WG] score of 0) at month 6.

RESULTS

All patients had severe active vasculitis at screening (mean ± SD BVAS/WG score 8.6 ± 3.2). Among the 123 patients whose disease was clinically in remission at month 6, levels of all markers except E-selectin showed significant declines. MMP-3 levels were also higher among the 23 patients with active disease at month 6 than among the 123 patients whose disease was in remission. MMP-3 levels correlated weakly with ESR and CRP levels.

CONCLUSION

Many markers of vascular injury and angiogenesis are elevated in severe active AAV and decline with treatment, but MMP-3 appears to distinguish active AAV from remission better than the other markers studied. Further study of MMP-3 is warranted to determine its clinical utility in combination with conventional markers of inflammation and ANCA titers.

Matrix metalloproteinase inhibitors as investigative tools in the pathogenesis and management of vascular disease

Matrix metalloproteinases (MMPs) are proteolytic enzymes that degrade various components of the extracellular matrix (ECM). MMPs could also regulate the activity of several non-ECM bioactive substrates and consequently affect different cellular functions. Members of the MMPs family include collagenases, gelatinases, stromelysins, matrilysins, membrane-type MMPs, and others. Pro-MMPs are cleaved into active MMPs, which in turn act on various substrates in the ECM and on the cell surface. MMPs play an important role in the regulation of numerous physiological processes including vascular remodeling and angiogenesis. MMPs may also be involved in vascular diseases such as hypertension, atherosclerosis, aortic aneurysm, and varicose veins. MMPs also play a role in the hemodynamic and vascular changes associated with pregnancy and preeclampsia. The role of MMPs is commonly assessed by measuring their gene expression, protein amount, and proteolytic activity using gel zymography. Because there are no specific activators of MMPs, MMP inhibitors are often used to investigate the role of MMPs in different physiologic processes and in the pathogenesis of specific diseases. MMP inhibitors include endogenous tissue inhibitors (TIMPs) and pharmacological inhibitors such as zinc chelators, doxycycline, and marimastat. MMP inhibitors have been evaluated as diagnostic and therapeutic tools in cancer, autoimmune disease, and cardiovascular disease. Although several MMP inhibitors have been synthesized and tested both experimentally and clinically, only one MMP inhibitor, i.e., doxycycline, is currently approved by the Food and Drug Administration. This is mainly due to the undesirable side effects of MMP inhibitors especially on the musculoskeletal system. While most experimental and clinical trials of MMP inhibitors have not demonstrated significant benefits, some trials still showed promising results. With the advent of new genetic and pharmacological tools, disease-specific MMP inhibitors with fewer undesirable effects are being developed and could be useful in the management of vascular disease.

Ulinastatin, a urinary trypsin inhibitor, for the initial treatment of patients with Kawasaki disease: a retrospective study

BACKGROUND

Markedly activated neutrophils or higher plasma levels of neutrophil elastase are involved in the poor response to intravenous immunoglobulin (IVIG) and the formation of coronary artery lesions (CAL) in patients with acute Kawasaki disease. We hypothesized that ulinastatin (UTI), by both direct and indirect suppression of neutrophils, would reduce the occurrence of CAL.

METHODS AND RESULTS

We retrospectively analyzed the clinical records of patients with Kawasaki disease between 1998 and 2009. Three hundred sixty-nine patients were treated with a combination of UTI, aspirin, and IVIG as an initial treatment (UTI group), and 1178 were treated with a conventional initial treatment, and IVIG with aspirin (control group). The baseline characteristics did not demonstrate notable differences between the two groups. The occurrence of CAL was significantly lower in the UTI group than in the control group (3% versus 7%; crude odds ratio [OR], 0.46; 95% confidence interval [CI], 0.25-0.86; P=0.01). The OR adjusted for sex, Gunma score (the predictive score for IVIG unresponsiveness), and dosage of initial IVIG (1 or 2 g/kg) was 0.32 (95% CI, 0.17-0.60; P<0.001). In addition, most CAL occurred in patients requiring additional rescue treatment and the proportion of those patients was significantly lower in the UTI group than in the control group (13% versus 22%; crude OR, 0.52; 95% CI, 0.38-0.73; P<0.001). The adjusted OR was 0.30 (95% CI, 0.20-0.44; P<0.001).

CONCLUSIONS

UTI was associated with fewer patients requiring additional rescue treatment and reduction of CAL in this retrospective study.

Epigenetic regulation of matrix metalloproteinases and their collagen substrates in cancer

Our review covers the recent epigenetic data that are focused on matrix metalloproteinases (MMPs), their inhibitors (tissue inhibitors of MMPs; TIMPs) and collagen substrates. Twenty-four MMPs, four TIMPs and at least 28 collagen types are known in humans. The MMP activity regulates the functionality of multiple extracellular matrix proteins, cytokines, growth factors and cell signaling and adhesion receptors. Aberrantly enhanced MMP proteolysis affects multiple cell functions, including proliferation, migration and invasion. This aberrant MMP proteolysis is frequently recorded in cancer. Recent evidence, however, indicates that several MMPs function as tumor suppressors in cancer. Their inhibition could have pro-tumorigenic effects (making them anti-targets), counterbalancing the benefits of target inhibition and leading to adverse effects in cancer patients. The current epigenetic data suggest that there are distinct multi-layered epigenetic mechanisms that regulate MMPs, TIMPs and collagens. We show that in certain cancer types, epigenetic signatures of selected MMPs exhibit stem cell-like characteristics. Epigenetic mechanisms appear to play an especially important role in glioblastoma multiforme. Glioblastomas/gliomas synthesize de novo and then deposit collagens into the brain parenchyma. The collagen deposition, combined with an enhanced MMP activity in glioblastomas/gliomas, facilitates rapid invasion of tumor cells through the brain. It is tempting to hypothesize that the epigenetic mechanisms which control MMPs, TIMPs and collagens and, consequently, tumor cell invasion, represent promising drug targets and that in the near future these targets will be challenged pharmacologically.

ITPKC single nucleotide polymorphism associated with the Kawasaki disease in a Taiwanese population

Kawasaki disease (KD) is characterized by systemic vasculitis with unknown etiology. Previous studies from Japan indicated that a gene polymorphism of ITPKC (rs28493229) is responsible for susceptibility to KD. We collected DNA samples from 1,531 Taiwanese subjects (341 KD patients and 1,190 controls) for genotyping ITPKC. In this study, no significant association was noted for the ITPKC polymorphism (rs28493229) between the controls and KD patients, although the CC genotype was overrepresented. We further combined our data with previously published case/control KD studies in the Taiwanese population and performed a meta-analysis. A significant association between rs28493229 and KD was found (Odds Ratio:1.36, 95% Confidence Interval 1.12-1.66). Importantly, a significant association was obtained between rs28493229 and KD patients with aneurysm formation (P = 0.001, under the recessive model). Taken together, our results indicated that C-allele of ITPKC SNP rs28493229 is associated with the susceptibility and aneurysm formation in KD patients in a Taiwanese population.

[What's new in paediatric dermatology?]

This paper summarizes a review of the medical literature focused on the field of pediatric dermatology from December 2009 to November 2010. Our objective was to select the papers published in the main journals of dermatology, internal medicine, pediatrics, infectious diseases and allergy that bring new information and significant advances concerning skin diseases in children. Recent advances in the field of infantile hemangiomas and atopic dermatitis are particularly detailed. This review also covers the main the following topics: psoriasis, Kawasaki disease, head lice and warts management, lichen, rare diseases such as epidermolyses bullosae.