Nitric oxide and aneurysm formation 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.

Percutaneous treatment of a coronary aneurysm by stent graft and drug-eluting stent implantation: a potential method to reduce stent graft restenosis

Coronary artery aneurysms (CAAs) can occur congenitally or secondary to specific disorders such as Kawasaki disease or atherosclerosis. Apart from a surgical approach, CAA can be treated by coronary stent graft (CSG) implantation. However, restenosis is frequent after CSG placement, precluding a wider use of this technique. We hypothesized that implantation of a drug-eluting stent (DES) within a CSG could be of use to avoid CSG restenosis. We report the case of a patient with a large aneurysm of the right coronary artery who underwent CSG implantation followed by DES placement. The immediate angiographic result showed complete exclusion of the aneurysm. Intravascular ultrasound confirmed good apposition of both the CSG and DES. Follow-up angiography after 23 weeks demonstrated a good long-term result without restenosis. The patient has remained asymptomatic during 12 months of follow-up. In conclusion, the present case suggests that CSG placement followed by DES implantation is a safe and effective approach to treat coronary aneurysms interventionally.

High-Flow-Induced Arterial Remodeling in Rats with Different Susceptibilities to Cerebral Aneurysms

BACKGROUND

The higher incidence of cerebral aneurysms (CAs) induced by enhanced arterial blood flow in Long Evans (LE) compared to Brown Norway (BN) rats suggests that intrinsic differences in high-flow arterial remodeling may be involved in determining CA susceptibility. Some aspects of this remodeling were compared in LE and BN rats after creation of an abdominal aortocaval fistula (ACF).

METHODS AND RESULTS

At 4 days with ACF, aortic luminal cross-sectional area (LCSA) determined by morphometry was increased by 20% in LE but not in BN rats. mRNA levels, determined by RT-PCR, were higher in LE than in BN rats for collagen alpha1(I), collagen alpha1(III), MMP2 and its inhibitor TIMP1 at 19 days with ACF. Nitric oxide synthase (NOS) mRNA levels were higher in LE rats at 4 days for the inducible (NOS2) isoform and at 4 and 19 days for the neuronal (NOS1) isoform. Aortic LCSA and NOS1 mRNA levels were tightly correlated and NOS inhibition prevented ACF-induced aortic remodeling in the LE rat. MMP2 and MMP7 activity, evaluated by zymography at 4 days with ACF, did not greatly differ between BN and LE.

CONCLUSIONS

These data suggest that a higher intrinsic ability for high-flow-induced arterial enlargement associated with NOS gene overexpression may be a possible genetic determinant in CA susceptibility.

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.

Nitric oxide metabolities in acute rheumatic fever

Acute rheumatic fever (ARF), is a systemic inflammatory disease etiologically related to infection with group A beta hemolytic streptococcus, characterized by a broad spectrum of disorders in cellular immunity. To estimate the activity of the immunopathological process in patients with ARF, plasma nitric oxide metabolities (NOx) concentrations, IL-1alpha and IL-2 levels were investigated in 22 patients with ARF at the time on admission, and after 3 months, in children with chronic rheumatic heart disease (CRHD). Plasma NOx concentrations, IL-1alpha and IL/2 levels in patients with ARF on admission were significantly higher than in the same patients 3 months later, and higher than in CRHD, or controls. Increased plasma NO may be a useful index for the quantitative assessment of the activity during immunological challenge. This information may be useful for the prognosis and monitoring of ARF.

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.

Nitric oxide metabolites in the urine of full-term and preterm infants

BACKGROUND

In newborn full-term and preterm infants the urine nitrites and nitrates (NOx) were measured, in order to investigate the effects of different pathological conditions (infection, hypoxia) on systemic nitric oxide production.

METHODS

Urine nitrites and nitrates were determined by means of the Griess reaction, after reduction of nitrates to nitrites with nitrate reductase.

RESULTS

The NOx level was higher in preterm (278 nmol/mL) than full-term (176 nmol/mL) infants. Low NOx (115 nmol/mL) levels accompanied generalized infections, while its high contents (650 nmol/mL) was found in cytomegalovirus and one case of Pneumocystis carinii infection. Moderate increase of NOx production was observed in infants with local pulmonary infections and encephalopathies.

CONCLUSIONS

The results indicate urinary NOx level is lowered in infants with life-threatening generalized infection. A possibility of a rapid test based on newborn urinary NOx level determination is considered.

Inhibition of inducible nitric oxide synthase limits nitric oxide production and experimental aneurysm expansion

PURPOSE

Nitric oxide (NO), frequently cited for its protective role, can also generate toxic metabolites known to degrade elastin. Both abdominal aortic aneurysms (AAAs) and inducible nitric oxide synthase (iNOS) are associated with inflammatory states, yet the relationship between NO production by iNOS and AAA development is unknown. The current study examines iNOS expression, NO production, and the effects of selective inhibition of iNOS by aminoguanidine in experimental AAA.

METHODS

An intra-aortic elastase infusion model was used. Control rats received intra-aortic saline infusion and postoperative intraperitoneal saline injections (Group 1). In the remaining groups, intra-aortic elastase infusion was used to induce aneurysm formation. These rats were treated with intraperitoneal injections of saline postoperatively (Group 2), aminoguanidine postoperatively (Group 3), or aminoguanidine preoperatively and postoperatively (Group 4). Aortic diameter and plasma nitrite/nitrate levels were measured on the day of surgery and postoperative day 7. Aortas were harvested for biochemical and histologic analysis on postoperative day 7.

RESULTS

Infusion of elastase produced AAAs (P <.001) with significant production of iNOS (P <.05) and nitrite/nitrate (P <.003) compared with controls. Selective inhibition of iNOS with aminoguanidine in elastase-infused aortas significantly reduced aneurysm size (P <.01) compared with elastase infusion alone. Aminoguanidine-treated rats displayed suppression of iNOS expression and plasma nitrite/nitrate production not significantly different from the control group. Histologic evaluation revealed equivalent inflammatory infiltrates in elastase-infused groups.

CONCLUSION

Expression of iNOS is induced and plasma nitrite/nitrate levels are increased in experimental AAA. Inhibition of iNOS limits NO production and iNOS expression, resulting in smaller aneurysm size. NO production by iNOS plays an important role with detrimental effects during experimental aneurysm development.

Kawasaki disease

Kawasaki disease is a leading cause of acquired heart disease in children in the USA. An acute vasculitis of unknown etiology, it occurs predominantly in infancy and early childhood, and more rarely in teenagers. Coronary artery aneurysms or ectasia develop in approximately 15-25% of children with the disease. Treatment with intravenous gamma globulin, 2 g per kg, in the acute phase reduces this risk three- to fivefold. Angiographic resolution occurs in approximately one-half of aneurysmal arterial segments, but these show persistent histologic and functional abnormalities. The remainder continue to be aneurysmal, often with development of progressive stenosis or occlusion. The worst prognosis occurs in children with so-called 'giant aneurysms', i.e. those with a maximum diameter greater than 8 mm, because thrombosis is promoted both by sluggish blood flow within the massively dilated vascular space and by the frequent development of stenotic lesions. Serial stress tests with myocardial imaging are mandatory in the management of patients with Kawasaki disease and significant coronary artery disease to determine the need for coronary angiography and transcatheter interventions or coronary bypass surgery. Continued long-term surveillance in patients with and without detected coronary abnormalities is necessary to determine the natural history of Kawasaki disease.

Relation between plasma nitrate and mean pulmonary arterial pressure in ventricular septal defect

BACKGROUND

Nitric oxide (NO) is known to modulate myocardial contraction and coronary tone, and its inhalation reduces pulmonary vascular resistance in patients with pulmonary hypertension.

OBJECTIVES

To evaluate the pathophysiological role of NO in patients with a ventricular septal defect (VSD).

PATIENTS

Twenty-nine children with VSD, nine of whom had undergone VSD closure surgery, and 14 patients with Kawasaki disease. The mean age of the VSD patients was 3.1 years (range, 2 months to 9 years).

METHODS

Using high performance liquid chromatography, nitrate (a more stable NO oxidation product) was measured in plasma specimens of the patients undergoing cardiac catheterisation.

RESULTS

Nitrate concentrations in the pulmonary artery bore a significant relation to mean pulmonary artery pressure, pulmonary to systemic systolic pressure ratio, and pulmonary to systemic flow ratio.

CONCLUSIONS

The concentration of nitrate was in proportion to the increment in intravascular or cardiac pressure, indicating that endogenous NO is upregulated as a compensatory homeostatic attempt to reduce pulmonary pressure and blood flow.

Increased serum levels of vascular endothelial growth factor in Kawasaki disease

Vascular endothelial growth factor (VEGF) is an angiogenic mitogen that specifically targets vascular endothelial cells. The objective of this study was to evaluate the role of VEGF in Kawasaki disease (KD), the most common cause of systemic vasculitis in childhood. Serum VEGF levels were measured by ELISA in 22 patients with KD, 22 febrile children with infection, and 19 healthy children. Samples from KD patients were divided into three groups: acute stage (n = 20), subacute stage (n = 13), and convalescent stage (n = 15). The results showed that KD patients in the acute and subacute stages had significantly higher levels of VEGF than did patients with infectious diseases and the healthy control subjects. When compared with the VEGF levels of patients with and without coronary artery lesions (CAL), significantly higher levels of VEGF were observed in the subacute stage in patients with CAL and in patients without CAL in the acute stage. Serial examination revealed that the serum VEGF levels in KD patients with CAL increased from a relatively low level in the acute stage to an extremely high level in the subacute stage. In contrast, patients without CAL were found to have extremely high levels of VEGF only in the acute stage of KD. In KD patients, the serum VEGF levels did not correlate with the inflammatory markers and clinical symptoms. Our results raise the possibility that VEGF is involved in the pathogenesis of KD, especially in the development of CAL. Further study is needed to clarify the biologic effect of VEGF on coronary arteries in 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).

Nitric oxide may trigger lactation in humans

OBJECTIVE

To determine whether nitric oxide is synthesized in the breast and plays a role in lactation.

DESIGN

Concentrations of biopterin, neopterin, and the total concentration of nitrite plus nitrate, a marker for nitric oxide generation were measured in 242 samples of breast milk obtained from 39 women during postpartum days 1 to 30. The total concentration of nitrite plus nitrate was measured in 17 sets of breast milk and serum obtained from 17 women on postpartum day 4 or 5.

RESULTS

(1) The total concentration of nitrite plus nitrate rose and peaked just before an increase in the volume of milk secreted was observed. (2) The total concentration of nitrite plus nitrate in breast milk was not correlated with that in the serum. (3) High levels of neopterin and biopterin were found in breast milk. (4) The volume of breast milk on day 5 was correlated with the total concentration of nitrite plus nitrate observed in breast milk on days 1 to 3. (5) The total concentration of nitrite plus nitrate in the breast milk of the high secretors significantly exceeded that seen in the low secretors.

CONCLUSIONS

We suggest that nitric oxide is synthesized in the breast and may trigger lactation in humans.