Endogenous nitric oxide production in Kawasaki disease

Markers of Endothelial Dysfunction in Kawasaki Disease: An Update

Kawasaki disease (KD) is a medium vessel vasculitis that has a special predilection for coronary arteries. Cardiovascular complications include the development of coronary artery abnormalities (CAAs) and myocarditis. Endothelial dysfunction (ED) is now recognized to be a key component in the pathogenesis of KD and is believed to contribute to the development of CAAs. ED has been evaluated by several clinical parameters. However, there is paucity of literature on laboratory markers for ED in KD. The evaluation of ED can be aided by the identification of biomarkers such as oxidative stress markers, circulating cells and their progenitors, angiogenesis factors, cytokines, chemokines, cell-adhesion molecules, and adipokines. If validated in multicentric studies, these biomarkers may be useful for monitoring the disease course of KD. They may also provide a useful predictive marker for the development of premature atherosclerosis that is often a concern during long-term follow-up of KD. This review provides insights into the current understanding of the significance of ED in KD.

Roles of Oxidative Injury and Nitric Oxide System Derangements in Kawasaki Disease Pathogenesis: A Systematic Review

Kawasaki disease (KD) is an acute febrile vasculitis that occurs mostly in children younger than five years. KD involves multiple intricately connected inflammatory reactions activated by a cytokine cascade. Despite therapeutic advances, coronary artery damage may develop in some patients, who will be at risk of clinical cardiovascular events and even sudden death. The etiology of KD remains unclear; however, it may involve both genetic and environmental factors leading to aberrant inflammatory responses. Given the young age of onset, prenatal or perinatal exposure may be etiologically relevant. Multisystem inflammatory syndrome in children, a post-infectious hyper-inflammatory disorder associated with severe acute respiratory syndrome coronavirus 2, has features that overlap with those of KD. Available evidence indicates that vascular endothelial dysfunction is a critical step in the sequence of events leading to the development of cardiovascular lesions in KD. Oxidative stress and the dysregulation of the nitric oxide (NO) system contribute to the pathogenesis of inflammatory responses related to this disease. This review provides current evidence and concepts highlighting the adverse effects of oxidative injury and NO system derangements on the initiation and progression of KD and potential therapeutic strategies for cardiovascular pathologies in affected children.

Urinary Colorimetric Sensor Array and Algorithm to Distinguish Kawasaki Disease from Other Febrile Illnesses

Objectives

Kawasaki disease (KD) is an acute pediatric vasculitis of infants and young children with unknown etiology and no specific laboratory-based test to identify. A specific molecular diagnostic test is urgently needed to support the clinical decision of proper medical intervention, preventing subsequent complications of coronary artery aneurysms. We used a simple and low-cost colorimetric sensor array to address the lack of a specific diagnostic test to differentiate KD from febrile control (FC) patients with similar rash/fever illnesses.

Study Design

Demographic and clinical data were prospectively collected for subjects with KD and FCs under standard protocol. After screening using a genetic algorithm, eleven compounds including metalloporphyrins, pH indicators, redox indicators and solvatochromic dye categories, were selected from our chromatic compound library (n = 190) to construct a colorimetric sensor array for diagnosing KD. Quantitative color difference analysis led to a decision-tree-based KD diagnostic algorithm.

Results

This KD sensing array allowed the identification of 94% of KD subjects (receiver operating characteristic [ROC] area under the curve [AUC] 0.981) in the training set (33 KD, 33 FC) and 94% of KD subjects (ROC AUC: 0.873) in the testing set (16 KD, 17 FC). Color difference maps reconstructed from the digital images of the sensing compounds demonstrated distinctive patterns differentiating KD from FC patients.

Conclusions

The colorimetric sensor array, composed of common used chemical compounds, is an easily accessible, low-cost method to realize the discrimination of subjects with KD from other febrile illness.

The number and function of circulating endothelial progenitor cells in patients with Kawasaki disease

Kawasaki disease (KD) is associated with coronary artery injury. Studies have shown that the endothelial progenitor cell (EPC) participates in the process of arterial repair. Data have been reported that the number of EPC increased significantly in the subacute phase of KD. However, until now, there are no data about the functions of EPC in KD patients. The present study was designed to further investigate the number and functions of EPC in KD. Ten KD patients in the acute phase and ten healthy volunteers were recruited and attributed to the KD group and control group, respectively. The circulating CD34/kinase insert domain-containing receptor double positive cells were evaluated in the two groups using flow cytometry. In vitro assays were used to measure the functions of EPC, including proliferation, adhesion, and migration activities. The plasma levels of nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), and high sensitivity C-reactive protein (hs-CRP) were also assessed in both groups. The number of EPC in the KD group was significantly higher than that of the control group (0.021 +/- 0.007% vs. 0.014 +/- 0.003%, P < 0.05). The migratory response of EPC was significantly decreased in the KD group, compared with that of the control group (5.50 +/- 1.78 vs. 3.40 +/- 1.35 cells/high power field, P < 0.01). Similarly, the proliferative and adhesive activities of EPC in the KD group were also decreased (0.47 +/- 0.08 vs. 0.66 +/- 0.07, P < 0.01; 6.5 +/- 2.12 vs. 11.2 +/- 2.04 cells/high power field, P < 0.01). The plasma NO, TNF-alpha, and hs-CRP levels in the KD group were higher than those of the control group (54.10 +/- 11.78 vs. 38.80 +/- 11.10 mumol/l, P < 0.01; 48.20 +/- 7.42 vs. 37.00 +/- 11.12 pg/ml, P < 0.05; 87.10 +/- 30.18 vs. 5.30 +/- 3.37 mg/l, P < 0.01). The number of circulating EPC positively correlated with the level of NO (r = 0.92, P < 0.001), and the functions of EPC negatively correlated with the levels of TNF-alpha and hs-CRP, respectively. In Kawasaki disease, the number of EPC was enhanced and the functions of EPC were attenuated. The two-way regulation of circulating EPC in KD patients may be associated with the disorders of cytokines or messengers in KD patients.

Leptin levels in Henoch–Schönlein purpura

The objective of this paper is to assess the possible role of nitric oxide (NO) and leptin in Henoch-Schönlein purpura (HSP). We investigated the serum leptin and total nitrite levels in 22 children with HSP in the acute phase and after remission and in 20 age- and sex-matched healthy control. Serum leptin levels (nanograms per milliliter; median, min-max) were statistically higher in the acute phase (12.9, 9.1-19.5) than those in the remission phase (6.1, 3.7-10.5, p<0.001) and in the control group (4.9, 3.8-7.5, p<0.001). Also, serum nitrite levels (micromole per liter; median, min-max) were higher in children in the acute phase (45.0, 32.0-60.0) compared to those in remission phase (30.5, 23.0-48.0) and in the control group (29.5, 18.0-38.0) (p<0.001, p<0.001, respectively). There was a positive correlation between serum leptin and total nitrite levels (r=0.65, p<0.001). We have demonstrated that serum leptin and NO levels were increased during the acute phase in children with HSP, and returned to normal levels in remission. We suggest that leptin and NO may have a role in the immunoinflammatory process of HSP, especially in the acute phase. Further studies are needed to clearly establish the roles of leptin and NO in the pathogenesis of HSP.

Adrenomedullin and total nitrite levels in children with Henoch-Schönlein purpura

Nitric oxide (NO) is synthesized from endothelium and has an important role in the control of vascular tonus. Adrenomedullin (AM) is a potent vasodilator, and cytoprotective peptide is produced not only in adrenal medulla, but also in the vascular smooth muscle and endothelial cells. To investigate the endothelial synthesis of AM and NO, and endothelial injury in Henoch-Schönlein purpura (HSP), we measured their levels in 16 children with HSP, who were evaluated during the acute and remission phases, and compared with 12 healthy controls. Plasma AM levels (pmol/ml) were significantly higher in acute phase children (46.87+/-11.49) than in those in remission (35.59+/-12.39, p<0.01) and controls (30.70+/-9.12, p<0.001). Similarly, plasma total nitrite levels (mumol/l) were higher in acute phase patients (47.50+/-12.30) than in those in remission (35.94+/-10.08, p<0.005) and controls (34.56+/-11.51, p<0.05). Urinary excretion of AM (pmol/mg creatinine) was higher in acute phase patients (53.85+/-23.22) than in remission patients (29.97+/-9.33, p<0.01) and controls (37.43+/-15.78, p<0.05). Patients had increased urinary nitrite excretion (mumol/mg creatinine) in acute phase (2.39+/-1.18) compared to those in remission (1.53+/-0.90, p<0.05) and controls (1.05+/-0.61, p<0.005). There was no significant difference between remission phase and controls in AM and nitrite levels ( p>0.05). This study concluded that AM and NO may have a role in the immunoinflammatory process of HSP, especially in the active stage, although whether this perpetuates, or protects against, further vascular injury is not clear. Further studies are needed to clearly establish the roles of AM and NO in the pathogenesis of HSP.

Serial changes of plasma nitrate in the acute phase of Kawasaki disease

BACKGROUND

Endogenous nitric oxide (NO) production increases with clinical conditions associated with immune stimulation. In Kawasaki disease (KD), various cytokines play a role in inflammatory reactions in the cardiovascular system. The authors hypothesized that elevated concentrations of nitrate was related to the severity of vasculitis. The aim of the present study was to evaluate serial changes of plasma nitrate concentrations in the acute phase of KD and to consider how NO is related to the inflammatory process of KD and to the coronary artery lesion (CAL).

METHODS

Thirty patients with KD and 20 age-matched healthy controls were enrolled in the present study. Blood samples were obtained weekly for the first and second months. The patients were divided into two groups: one with CAL (n = 11) and another without CAL (n = 19). Plasma nitrate was measured by high-performance liquid chromatography.

RESULTS

In both groups, plasma nitrate increased remarkably from the first week to the third week. Peak concentrations of nitrate (mean +/- SD, micro mol/L) in each group were as follows: 56.9 +/- 23.8 in the CAL(+) group and 68.2 +/- 33.8 in the CAL(-) group. Plasma nitrate decreased from the third week to the second month but was still elevated in both groups in comparison with the age-matched healthy controls. There was no correlation between plasma nitrates and white blood cell count or C-reactive protein, respectively (r = 0.013, 0.075).

CONCLUSIONS

The results suggest that NO production may not be related to the severity of vascular inflammation and that elevated nitrate during the first month of illness may not be associated with a higher risk of CAL.

Inducible and endothelial constitutive nitric oxide synthase gene polymorphisms in Kawasaki disease

BACKGROUND

Nitric oxide (NO) is secreted by immune and vascular endothelial cells, and appears to play important roles in the pathophysiology of Kawasaki disease (KD). Thus, genetic variations in NO synthase (NOS) genes may be involved in the development of coronary artery lesions (CAL) in KD.

METHODS

The present study investigated the association of endothelial constitutive NOS (ecNOS) and inducible NOS (iNOS) gene polymorphisms with the development of CAL in KD in a Japanese population.

RESULTS

The genotype distributions of 27-bp tandem repeat polymorphism within intron 4 of ecNOS gene did not show any significant difference between controls and KD patients with or without CAL. In addition, there was no significant association between whole-allele distribution of iNOS gene promoter (penta-repeat CCTTT) polymorphism and KD with or without CAL.

CONCLUSION

These results did not support any association of ecNOS and iNOS gene polymorphisms to the development of CAL in KD patients in a Japanese population.

Decreased nitric oxide production after intravenous immunoglobulin treatment in patients with Kawasaki disease

OBJECTIVE

To assess nitric oxide (NO) production and different displays of NO synthase (NOS) isoforms in patients with Kawasaki disease (KD) before and after intravenous immunoglobulin (IVIG) treatment.

STUDY DESIGN

Blood and urine samples were collected from patients with KD before IVIG treatment and 3 days afterward. Age-matched febrile patients with various diseases served as control patients. Plasma NOx (NO3- + NO2-) levels were measured as NO production. Real-time reverse transcriptase-polymerase chain reaction and immunohistochemical staining were used to detect differential NOS isoform expression in mononuclear leukocytes (MNCs).

RESULTS

Patients with KD (n = 40) had higher levels of NOx than the non-KD febrile control patients. The elevated NOx levels in patients with KD were significantly associated with the occurrence of coronary artery dilation (>3 mm). These elevated NOx levels significantly decreased after IVIG treatment (157.8 +/- 15.9 micromol/L vs 57.0 +/- 4.27 micromol/L, P <.01). However, excretion of urinary NOx levels was not changed after IVIG treatment. Inducible but not constitutive NOS mRNA and protein in MNCs were prominently expressed but significantly decreased after IVIG treatment.

CONCLUSIONS

IVIG may suppress iNOS expression of MNCs in patients with KD, thus decreasing NO-mediated inflammatory responses and coronary artery dilation.

Methylenetetrahydrofolate reductase polymorphism in Kawasaki disease

BACKGROUND

A genetic aberration in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene (677 C to T substitution) has been shown to result in reduced enzyme activity. The hypothesis tested in the present study was that a higher proportion of Kawasaki disease (KD) patients with coronary artery lesions (CAL) would have the T677 allele compared with patients without CAL and healthy subjects.

METHODS

Genotypes for MTHFR were determined in 75 KD patients (male:female ratio 52:23) and 238 healthy subjects (male:female ratio, 110:128) by the polymerase chain reaction and restriction fragment length polymorphism method.

RESULTS

The results indicated that female KD patients had a significantly higher frequency of the TT genotype compared with female control subjects. In the female population, the frequency of the TT genotype in patients with initial coronary aneurysm was significantly lower than in patients without this manifestation. Analysis of the data for the male population showed that the frequency of the TT genotype in KD patients developing coronary stenosis, occlusion or myocardial infarction was higher than that in those without these manifestations, although the difference was statistically insignificant.

CONCLUSIONS

The TT genotype may protect female KD patients against initial aneurysm formation and predispose male KD patients to severe coronary complications. Further large-scale studies may be required to confirm the contribution of homocysteine in the coronary sequelae of KD.

Nitrite and nitrate analyses: a clinical biochemistry perspective

OBJECTIVE

To review the assays available for measurement of nitrite and nitrate ions in body fluids and their clinical applications.

DESIGN AND METHODS

Literature searches were done of Medline and Current Contents to November 1997.

RESULTS

The influence of dietary nitrite and nitrate on the concentrations of these ions in various body fluids is reviewed. An overview is presented of the metabolism of nitric oxide (which is converted to nitrite and nitrate). Methods for measurement of the ions are reviewed. Reference values are summarized and the changes reported in various clinical conditions. These include: infection, gastroenterological conditions, hypertension, renal and cardiac disease, inflammatory diseases, transplant rejection, diseases of the central nervous system, and others. Possible effects of environmental nitrite and nitrate on disease incidence are reviewed.

CONCLUSIONS

Most studies of changes in human disease have been descriptive. Diagnostic utility is limited because the concentrations in a significant proportion of affected individuals overlap with those in controls. Changes in concentration may also be caused by diet, outside the clinical investigational setting. The role of nitrite and nitrate assays (alongside direct measurements of nitric oxide in breath) may be restricted to the monitoring of disease progression, or response to therapy in individual patients or subgroups. Associations between disease incidence and drinking water nitrate content are controversial (except for methemoglobinemia in infants).