Serum amyloid A and high density lipoprotein participate in the acute phase response of Kawasaki disease

Differential expression of long non-coding RNAs SRA, HCG22 and MHRT in children with Kawasaki disease

Kawasaki disease (KD) is an acute, self-limited inflammatory illness during childhood that may lead to thrombosis in the coronary arteries (CA). The major aims of the present study were to estimate the serum levels of long non-coding RNAs (lncRNAs) and the metabolic profiles of patients with KD. A total of 40 specimens were obtained from pediatric patients (40 specimens before and 40 specimens after treatment) who were diagnosed with KD (n=40). The controls comprised healthy children without KD (n=40). The serum levels of lncRNAs steroid receptor RNA activator (SRA), human leukocyte antigen complex group 22 (HCG22) and myosin heavy chain-associated RNA transcript (MHRT) were determined using reverse transcription-quantitative PCR. Subsequently, the correlation between the expression levels of lncRNAs and biochemical parameters of patients was assessed. Receiver operating characteristic curves were constructed to determine the diagnostic value of the lncRNAs. The results indicated that the serum levels of lncRNAs SRA and HCG22 were higher in patients with acute KD compared with those in healthy controls. B-type natriuretic peptide (BNP) and C-reactive protein were positively correlated with HCG22 in patients with acute KD, while total cholesterol and low-density lipoprotein were negatively correlated with HCG22 in patients with acute KD. The lncRNA MHRT was significantly upregulated in convalescent KD compared with acute KD following intravenous immunoglobulin therapy. In patients with convalescent KD, creatine kinase was positively correlated with MHRT, while BNP and adenosine deaminase were negatively correlated with MHRT. In conclusion, to the best of our knowledge, the present study was the first to identify that the serum levels of lncRNAs SRA and HCG22 in patients with acute KD were higher compared with those in control subjects. MHRT levels in patients with convalescent KD were higher than those in the acute phase. LncRNAs SRA and HCG22 may have crucial roles in KD and are potential novel diagnostic biomarkers for KD. LncRNA MHRT may be considered a novel biomarker for predicting the clinical prognosis of patients with KD.

Interaction between high-density lipoproteins and inflammation: Function matters more than concentration!

High-density lipoprotein (HDL) plays an important role in lipid metabolism and especially contributes to the reverse cholesterol transport pathway. Over recent years it has become clear that the effect of HDL on immune-modulation is not only dependent on HDL concentration but also and perhaps even more so on HDL function. This review will provide a concise general introduction to HDL followed by an overview of post-translational modifications of HDL and a detailed overview of the role of HDL in inflammatory diseases. The clinical potential of HDL and its main apolipoprotein constituent, apoA-I, is also addressed in this context. Finally, some conclusions and remarks that are important for future HDL-based research and further development of HDL-focused therapies are discussed.

Arterial stiffness late after Kawasaki disease in children: Assessment by performing brachial-ankle pulse wave velocity

BACKGROUND

Whether low-risk Kawasaki disease (KD) patients are at increased risk of cardiovascular disease later in life remains controversial. The purpose of this study is to examine the arterial stiffness and exercise performance of KD patients in chronic stage.

METHODS

This study included 158 subjects. They were divided into three groups: 37 KD patients with regressed coronary artery lesions (CALs) (M/F 23/14, 13.6 ± 6.5 years) (group I), 43 KD patients without CALs (M/F 26/17, 13.9 ± 6.2 years) (group II), and 78 age- and gender-matched normal controls (M/F 44/34, 13.2 ± 6.9 years) (group III). They all underwent brachial-ankle pulse wave velocity (baPWV), an exercise test, and blood sampling to measure the levels of high-sensitivity C-reactive protein (hs-CRP), triglycerides (TG), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and total cholesterol (TC). The differences among the groups were compared.

RESULTS

There were significant differences among the three groups in terms of right and left baPWV (p < 0.01 respectively), HDL level (p < 0.05), TC/HDL ratio (p < 0.05), and oxygen consumption (VO2) peak (p < 0.05). Moreover, group I subjects had significantly higher right and left baPWV (p < 0.05 respectively), lower HDL level (p < 0.05), and lower VO2 peak (p < 0.05) than group II subjects. Furthermore, baPWV was significantly correlated with TG level (r = 0.326, p < 0.05), TC/HDL ratio (r = 0.483, p < 0.01), LDL level (r = 0.386, p < 0.01), and VO2 peak (r = -0.385, p < 0.05) in group I subjects. Only the TC/HDL ratio was found to be a significant correlating factor for an increase of baPWV (beta = 0.68, p < 0.05) in KD patients after multiple linear regression.

CONCLUSION

Our results suggest that arterial stiffness is present late after KD and may adversely affect exercise performance, especially in patients with regressed CALs. Regular measurement of baPWV may be indicated in the long-term follow-up of KD patients.

Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association

BACKGROUND

Kawasaki disease is an acute vasculitis of childhood that leads to coronary artery aneurysms in ≈25% of untreated cases. It has been reported worldwide and is the leading cause of acquired heart disease in children in developed countries.

METHODS AND RESULTS

To revise the previous American Heart Association guidelines, a multidisciplinary writing group of experts was convened to review and appraise available evidence and practice-based opinion, as well as to provide updated recommendations for diagnosis, treatment of the acute illness, and long-term management. Although the cause remains unknown, discussion sections highlight new insights into the epidemiology, genetics, pathogenesis, pathology, natural history, and long-term outcomes. Prompt diagnosis is essential, and an updated algorithm defines supplemental information to be used to assist the diagnosis when classic clinical criteria are incomplete. Although intravenous immune globulin is the mainstay of initial treatment, the role for additional primary therapy in selected patients is discussed. Approximately 10% to 20% of patients do not respond to initial intravenous immune globulin, and recommendations for additional therapies are provided. Careful initial management of evolving coronary artery abnormalities is essential, necessitating an increased frequency of assessments and escalation of thromboprophylaxis. Risk stratification for long-term management is based primarily on maximal coronary artery luminal dimensions, normalized as Z scores, and is calibrated to both past and current involvement. Patients with aneurysms require life-long and uninterrupted cardiology follow-up.

CONCLUSIONS

These recommendations provide updated and best evidence-based guidance to healthcare providers who diagnose and manage Kawasaki disease, but clinical decision making should be individualized to specific patient circumstances.

A Novel Truncated Form of Serum Amyloid A in Kawasaki Disease

Background

Kawasaki disease (KD) is an acute vasculitis in children that can cause coronary artery abnormalities. Its diagnosis is challenging, and many cytokines, chemokines, acute phase reactants, and growth factors have failed evaluation as specific biomarkers to distinguish KD from other febrile illnesses. We performed protein profiling, comparing plasma from children with KD with febrile control (FC) subjects to determine if there were specific proteins or peptides that could distinguish the two clinical states.

Materials and Methods

Plasma from three independent cohorts from the blood of 68 KD and 61 FC subjects was fractionated by anion exchange chromatography, followed by surface-enhanced laser desorption ionization (SELDI) mass spectrometry of the fractions. The mass spectra of KD and FC plasma samples were analyzed for peaks that were statistically significantly different.

Results

A mass spectrometry peak with a mass of 7,860 Da had high intensity in acute KD subjects compared to subacute KD (p = 0.0003) and FC (p = 7.9 x 10⁻¹⁰) subjects. We identified this peak as a novel truncated form of serum amyloid A with N-terminal at Lys-34 of the circulating form and validated its identity using a hybrid mass spectrum immunoassay technique. The truncated form of serum amyloid A was present in plasma of KD subjects when blood was collected in tubes containing protease inhibitors. This peak disappeared when the patients were examined after their symptoms resolved. Intensities of this peptide did not correlate with KD-associated laboratory values or with other mass spectrum peaks from the plasma of these KD subjects.

Conclusions

Using SELDI mass spectrometry, we have discovered a novel truncated form of serum amyloid A that is elevated in the plasma of KD when compared with FC subjects. Future studies will evaluate its relevance as a diagnostic biomarker and its potential role in the pathophysiology of KD.

Levels of High-Density Lipoprotein Cholesterol are Associated With Biomarkers of Inflammation in Patients With Acute Coronary Syndrome

Pathologic conditions associated with inflammation show an inverse correlation between high-density lipoprotein cholesterol (HDL-C) and inflammatory biomarker levels. Our aim was to investigate, in patients with acute coronary syndrome (ACS), whether very low HDL-C levels are associated with inflammatory biomarkers. In a cross-sectional study, we included 6,134 patients with ACS; they were classified as having very low (<30 mg/dl), low (30 to 39.9 mg/dl), and normal HDL-C (≥ 40 mg/dl) levels. We analyzed the association of different categories of HDL-C levels with serum levels of inflammatory biomarkers, high-sensitivity C-reactive protein (hs-CRP), albumin, and white blood cell count at admission. Overall, 18.5% of patients had very low HDL-C levels. Patients with very low HDL-C levels, compared to patients with low or normal HDL-C levels, had the highest hs-CRP (median 17.8 [interquartile range 7.2 to 54.5] vs 12.6 [5.6 to 33.9] vs 12.0 [5.4 to 36.9] mg/L, respectively, p <0.001) and the lowest albumin levels (median 3.6 [IQR 3.3 to 4.0] vs 3.8 [3.5 to 4.0] vs 3.8 [3.5 to 4.1] g/dl, respectively, p <0.001). White blood cell count did not differ significantly (p = 0.40). The multivariate analysis showed that albumin ≤ 3.5 g/dl (odds ratio 2.16, 95% confidence interval 1.88 to 2.49, p <0.001) and hs-CRP ≥ 10 mg/L (odds ratio 1.35, 95% confidence interval 1.17 to 1.55, p <0.001) were independent predictors of very low HDL-C levels. Patients with very low HDL-C levels had the highest inhospital mortality rates compared with the other groups. In conclusion, in patients with ACS, hs-CRP and serum albumin were associated independently with very low HDL-C levels.

Impact of systemic inflammation and autoimmune diseases on apoA-I and HDL plasma levels and functions

The cholesterol of high-density lipoproteins (HDLs) and its major proteic component, apoA-I, have been widely investigated as potential predictors of acute cardiovascular (CV) events. In particular, HDL cholesterol levels were shown to be inversely and independently associated with the risk of acute CV diseases in different patient populations, including autoimmune and chronic inflammatory disorders. Some relevant and direct anti-inflammatory activities of HDL have been also recently identified targeting both immune and vascular cell subsets. These studies recently highlighted the improvement of HDL function (instead of circulating levels) as a promising treatment strategy to reduce inflammation and associated CV risk in several diseases, such as systemic lupus erythematosus and rheumatoid arthritis. In these diseases, anti-inflammatory treatments targeting HDL function might improve both disease activity and CV risk. In this narrative review, we will focus on the pathophysiological relevance of HDL and apoA-I levels/functions in different acute and chronic inflammatory pathophysiological conditions.

Functionality of HDL: antioxidation and detoxifying effects

High-density lipoproteins (HDL) are complexes of multiple talents, some of which have only recently been recognised but all of which are under active investigation. Clinical interest initially arose from their amply demonstrated role in atherosclerotic disease with their consequent designation as a major cardiovascular disease (CVD) risk factor. However, interest is no longer confined to vascular tissues, with the reports of impacts of the lipoprotein on pancreatic, renal and nervous tissues, amongst other possible targets. The ever-widening scope of HDL talents also encompasses environmental hazards, including infectious agents and environmental toxins. In almost all cases, HDL would appear to have a beneficial impact on health. It raises the intriguing question of whether these various talents emanate from a basic ancestral function to protect the cell.The following chapter will illustrate and review our current understanding of some of the functions attributed to HDL. The first section will look at the antioxidative functions of HDL and possible mechanisms that are involved. The second section will focus specifically on paraoxonase-1 (PON1), which appears to bridge the divide between the two HDL functions discussed herein. This will lead into the final section dealing with HDL as a detoxifying agent protecting against exposure to environmental pathogens and other toxins.

Vascular health late after Kawasaki disease: implications for accelerated atherosclerosis

Kawasaki disease (KD), an acute vasculitis that primarily affects young children, is the most common acquired paediatric cardiovascular disease in developed countries. While sequelae of arterial inflammation in the acute phase of KD are well documented, its late effects on vascular health are increasingly unveiled. Late vascular dysfunction is characterized by structural alterations and functional impairment in term of arterial stiffening and endothelial dysfunction and shown to involve both coronary and systemic arteries. Further evidence suggests that continuous low grade inflammation and ongoing active remodeling of coronary arterial lesions occur late after acute illness and may play a role in structural and functional alterations of the arteries. Potential importance of genetic modulation on vascular health late after KD is implicated by associations between mannose binding lectin and inflammatory gene polymorphisms with severity of peripheral arterial stiffening and carotid intima-media thickening. The changes in cholesterol and lipoproteins levels late after KD further appear similar to those proposed to be atherogenic. While data on adverse vascular health are less controversial in patients with persistent or regressed coronary arterial aneurysms, data appear conflicting in individuals with no coronary arterial involvements or only transient coronary ectasia. Notwithstanding, concerns have been raised with regard to predisposition of KD in childhood to accelerated atherosclerosis in adulthood. Until further evidence-based data are available, however, it remains important to assess and monitor cardiovascular risk factors and to promote cardiovascular health in children with a history of KD in the long term.

Persistent endothelial damage after intravenous immunoglobulin therapy in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute systemic vasculitis of unknown etiology. Although endothelial cell damage associated with vasculitis might lead to the hypercoagulability that is involved in coronary artery disease, the changes in coagulation after intravenous immunoglobulin therapy (IVIG) have not been well investigated in KD. The aims of this study were to address the changes in coagulation before and after IVIG in KD, and to further elucidate the coagulation-inflammation axis, with special attention to endothelial damage.

METHODS

We retrospectively collected the laboratory data before and after IVIG in 26 pediatric KD patients treated at the Nara Prefecture Western Medical Center between May 2010 and April 2012. Prothrombin time (PT), activated partial thromboplastin time (APTT) and levels of fibrin/fibrinogen degradation products (FDP) and D-dimer were assessed as coagulation markers. Fibrinogen, ferritin, serum amyloid A, procalcitonin and urine β2 microglobulin were assessed as inflammation markers. Thrombomodulin, antithrombin, factor VIII activity (FVIII:C), and von Willebrand factor antigen (VWF:Ag) were used to assess endothelial damage.

RESULTS

Prolonged PT and APTT before IVIG were significantly shortened after IVIG, and elevated levels of FDP and D-dimer were significantly decreased. Elevated levels of inflammation markers had decreased significantly after IVIG, but levels of FVIII:C and VWF:Ag remained high, even after IVIG.

CONCLUSIONS

Ameliorated inflammation by IVIG might improve the hypercoagulable state. Nevertheless, our results suggest that endothelial damage might be prolonged in IVIG-treated patients. Control of endothelial damage in KD is critical.

Cardiovascular risk factors of early atherosclerosis in school-aged children after Kawasaki disease

Purpose

The aim of this study was to determine whether school-aged children with Kawasaki disease (KD) have an increased risk for early atherosclerosis.

Methods

The study included 98 children. The children were divided into the following groups: group A (n=19), KD with coronary arterial lesions that persisted or regressed; group B (n=49), KD without coronary arterial lesions; and group C (n=30), healthy children. Anthropometric variables and the levels of biochemical markers, including total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A, apolipoprotein B, homocysteine, high-sensitivity C-reactive protein (hs-CRP), and brachial artery stiffness using pulse wave velocity were compared among the three groups.

Results

There were no significant differences in blood pressure and body index among the three groups. Additionally, there was no sex-specific difference. Moreover, the levels of triglyceride, HDL-C, apolipoprotein A, and hs-CRP did not differ among the three groups. However, the levels of total cholesterol (P=0.018), LDL-C (P=0.0003), and apolipoprotein B (P=0.029) were significantly higher in group A than in group C. Further, the level of homocysteine and the aortic pulse wave velocity were significantly higher in groups A and B than in group C (P=0.0001).

Conclusion

School-aged children after KD have high lipid profiles and arterial stiffness indicating an increased risk for early atherosclerosis.

Human apolipoprotein A-I is associated with dengue virus and enhances virus infection through SR-BI

Diseases caused by dengue virus (DV) infection vary in severity, with symptoms ranging from mild fever to life threatening dengue hemorrhage fever (DHF) and dengue shock syndrome (DSS). Clinical studies have shown that significant decrease in the level of lipoproteins is correlated with severe illness in DHF/DSS patients. Available evidence also indicates that lipoproteins including high-density lipoprotein (HDL) and low-density lipoprotein (LDL) are able to facilitate cell entry of HCV or other flaviviruses via corresponding lipoprotein receptors. In this study, we found that pre-incubation of DV with human serum leads to an enhanced DV infectivity in various types of cells. Such enhancement could be due to interactions between serum components and DV particles. Through co-immunoprecipitation we revealed that apolipoprotein A-I (ApoA-I), the major protein component in HDL, is associated with DV particles and is able to promote DV infection. Based on that observation, we further found that siRNA knockdown of the scavenger receptor class B type I (SR-BI), the cell receptor of ApoA-I, abolished the activity of ApoA-I in enhancement of DV infection. This suggests that ApoA-I bridges DV particles and cell receptor SR-BI and facilitates entry of DV into cells. FACS analysis of cell surface dengue antigen after virus absorption further confirmed that ApoA-I enhances DV infection via promoting initial attachment of the virus to cells. These findings illustrate a novel entry route of DV into cells, which may provide insights into the functional importance of lipoproteins in dengue pathogenesis.

AC13, a C-terminal fragment of apolipoprotein A-I, is a candidate biomarker for microscopic polyangiitis

OBJECTIVE

Microscopic polyangiitis (MPA) is necrotizing vasculitis of unknown etiology. We analyzed the serum peptide profile of MPA to find a biomarker for this disease.

METHODS

Serum peptides from 33 patients with MPA, 7 with granulomatosis with polyangiitis (Wegener's), 7 with Churg-Strauss syndrome, 6 with giant cell arteritis, and 25 with systemic lupus erythematosus (SLE) were comprehensively analyzed by mass spectrometry. Peptide function on human microvascular endothelial cells (HMVECs) was examined by enzyme-linked immunosorbent assay and real-time polymerase chain reaction.

RESULTS

A total of 102 serum peptides were detected from the 78 patients. One of the peptides, peptide 1,523, showed significantly higher ion intensity in MPA (mean ± SD 46.8 ± 39.3 arbitrary units [AU]) than in the other systemic vasculitides (14.1 ± 12.2 AU) (P < 0.05) or in SLE (17.0 ± 12.1 AU) (P < 0.05). In MPA, peptide 1,523 showed significantly higher ion intensity before treatment than 1 week (P < 0.05) and 6 weeks (P < 0.05) after the initiation of treatment. Peptide 1,523 was identified as 13 C-terminal amino acid residues of apolipoprotein A-I (Apo A-I) and was designated "AC13." Validation of AC13 ion intensity using another MPA cohort (n = 14) similarly showed significantly higher ion intensity (90.1 ± 167.9 AU) compared to 14 patients with rheumatoid arthritis (8.6 ± 5.4 AU) (P < 0.01) and 14 healthy subjects (11.8 ± 6.1 AU) (P < 0.01). Serum concentrations of Apo A-I and high-density lipoprotein cholesterol were down-regulated in MPA before treatment and returned to their normal ranges 6 weeks after the initiation of treatment (both P < 0.01). Stimulation of HMVECs with AC13 significantly up-regulated secretion of interleukin-6 (IL-6) (P < 0.05) and IL-8 (P < 0.01).

CONCLUSION

AC13, a candidate biomarker for MPA, may be useful for monitoring disease activity and may exacerbate vascular inflammation through up-regulation of proinflammatory cytokines.

The role of atorvastatin in regulating the immune response leading to vascular damage in a model of Kawasaki disease

Superantigens have been implicated in a number of diseases including Kawasaki disease (KD), a multi-system vasculitis resulting in coronary artery aneurysms. We have characterized a murine disease model in which coronary arteritis is induced by a novel superantigen found in Lactobacillus casei cell wall extract (LCWE). Using this animal model of KD, we have identified three pathogenic steps leading to coronary artery aneurysm formation. These steps include T cell activation and proliferation, production of the proinflammatory cytokine tumour necrosis factor (TNF)-α and up-regulation of matrix metalloproteinase 9 (MMP-9), an elastolytic protease. In addition to their cholesterol-lowering effects, 3-hydroxy-3-methylglutaryl (HMG) coenzyme A (CoA) reductase inhibitors (statins) have pleotropic immunomodulatory properties. Thus, we examined the effect of atorvastatin in modulating each of these three critical pathogenic processes leading to aneurysm formation in the disease model. Atorvastatin inhibited lymphocyte proliferation in response to superantigen stimulation in a dose-dependent manner. This inhibition was also observed for production of soluble mediators of inflammation including interleukin (IL)-2 and TNF-α. The inhibitory effect on proliferation was rescued completely by mevalonic acid, confirming that the mechanism responsible for this inhibitory activity on immune activation was inhibition of HMG-CoA reductase. Similarly, TNF-α-induced MMP-9 production was reduced in a dose-dependent manner in response to atorvastatin. Inhibition of extracellular-regulated kinase (ERK) phosphorylation appears to be the mechanism responsible for inhibition of MMP-9 production. In conclusion, atorvastatin is able to inhibit critical steps known to be important in the development of coronary aneurysms, suggesting that statins may have therapeutic benefit in patients with KD.

Acute-phase reactants and a supplemental diagnostic aid for Kawasaki disease

The diagnosis of acute Kawasaki disease (KD) is based on characteristic clinical signs and not on a specific diagnostic test. The authors performed a comprehensive evaluation of acute-phase reactants in KD to determine which of the acute-phase reactants would most accurately distinguish KD from other febrile illnesses. Blood was collected from 218 cases of febrile children with KD (64 cases); bacterial pneumonia (74 cases); hand, foot, and mouth disease (31 cases); and upper respiratory tract infection (49 cases) in acute-stage illness before any therapy. The demographics, body temperature, and laboratory markers including white blood cell count, red blood cell count, and levels of hemoglobin, platelets, C-reactive protein, haptoglobin, apolipoprotein A-I, and apolipoprotein B were evaluated. Using post hoc analysis, the platelet count (10(3)/μl) and haptoglobin/apolipoprotein A-I ratio were significantly higher for the KD patients (404.64 ± 161.68, P = 0.004; 4.74 ± 2.73, P < 0.001) than for the other groups including patients with pneumonia (272.76 ± 115.07, 2.03 ± 1.88); hand, foot, and mouth disease (274 ± 105.9, 2.24 ± 1.19); and upper respiratory tract infection (282.06 ± 107.72, 1.4 ± 0.98). The best cutoff value of the haptoglobin/apolipoprotein A-I ratio obtained from receiver operating characteristics (ROC) curves for KD was 2 (area under the ROC curve, 0.88; 95% confidence interval, 0.801-0.955), with a sensitivity of 89.7% and a specificity of 85.6% for detecting KD. Our data indicate that the serum haptoglobin/apolipoprotein A-I ratio could be a useful supplemental laboratory marker for the acute phase of KD.

Plasma clusterin levels in predicting the occurrence of coronary artery lesions in patients with Kawasaki disease

Kawasaki disease (KD) is the leading cause of acquired heart disease during childhood in the developed countries. Coronary artery lesions (CAL) are the major complications of KD. A unique proteomic profiling with increased or decreased fibrinogen, alpha-1-antitrypsin, clusterin, and immunoglobulin free light chains were noted in KD in our previous study. The purpose of this study was to evaluate relations between these biomarkers and CAL in KD and to establish within the markers the appropriate cut-off value with which to predict the occurrence of CAL. A total of 47 KD patients were enrolled, including 14 with CAL and 33 without CAL. Plasma samples from patients with KD before intravenous immunoglobulin administration were indicated for measurement of these biomarkers. A potential relation among CAL, clinical characteristics, and these biomarkers was investigated, and a receiver operating characteristic curve was used to identify a cut-off value of the significant marker that best predicated the occurrence of CAL. Among these biomarkers, only plasma clusterin level was associated with the occurrence of CAL. Using a cut-off value of clusterin <12.0 mg/l, the relative risk for CAL was 4.53-fold (95% confidence interval [CI] 1.060-19.347%, P = 0.014). Results from this study suggest that plasma clusterin level <12.0 mg/l in KD is significantly associated with the occurrence of CAL. Results from this study provide a potential biomarker of KD that may help predict the occurrence of CAL.

Kawasaki disease: a review with emphasis on cardiovascular complications

Kawasaki disease (KD) is an acute systemic vasculitis that is currently the leading cause of acquired heart disease in childhood in the United States. Cardiovascular complications are the major cause of morbidity, are responsible for virtually all deaths from KD and should be evaluated as soon as possible after the acute phase to establish the baseline status, in order to predict disease progression and determine adequate treatment. In selected patients, electrocardiography (ECG)-gated cardiac computed tomography (CT) and magnetic resonance (MR) imaging are valuable non-invasive techniques that can be used to help diagnose the cardiovascular complications associated with KD. In this article, we review the epidemiology, aetiology and pathogenesis, histopathology, clinical features, cardiovascular complications and imaging, focusing on the role of cardiac CT and MR on the initial assessment and follow-up of the cardiovascular complications of KD.

Age-related acceleration of endothelial dysfunction and subclinical atherosclerosis in subjects with coronary artery lesions after Kawasaki disease

The objective of this study was to test the hypothesis that accelerated endothelial dysfunction and the development of premature atherosclerosis are associated with age in subjects with coronary artery lesions after Kawasaki disease (KD). A case-control study was performed at a university hospital that included 35 post-KD subjects across a wide age range (range, 8-42 years) without traditional cardiovascular risk factors and 35 age- and sex-matched healthy control subjects (Cont). Flow-mediated dilatation (FMD) of the brachial artery-induced by reactive hyperemia, intima media thickness (IMT), and elastic modulus (Ep) of the common carotid artery were compared between KD and Cont subjects assessed against age. KD subjects had slightly higher levels of body mass index, lipid profile, and HbA1c than Cont subjects, but the differences were not significant. The mean IMT (p < 0.001), age-adjusted percentage normal IMT (%N IMT; p < 0.0001), and Ep (p < 0.001) were significantly higher in KD than Cont subjects, and the peak FMD% (p < 0.01) was significantly lower in KD than Cont subjects. There were significant correlations between FMD% and age (r = -0.51 p < 0.0001), IMT and age (r = 0.68, p < 0.001), and Ep and age (r = 0.58, p < 0.01) in KD but not Cont subjects. When the difference in FMD% between KD and matched Cont subjects (DeltaFMD%) was plotted against age, no significant relationship was found, although significant correlations between DeltaIMT and age (r = 0.52, p < 0.01) as well as between DeltaEp and age (r = 0.46, p < 0.05) were observed. When we defined values that were +2.0 SD over the mean control values (i.e., %N IMT >or= 120% and/or Ep >or= 50 kPa) as markers of subclinical atherosclerosis, 15 subjects met the criteria. Subjects over the age of 22 years were more likely to have (OR = 16.54, p = 0.0001) subclinical atherosclerosis in this cohort. Our results suggest that endothelial dysfunction and the development of premature atherosclerosis were accelerated in adult post-KD compared to Cont subjects.

Cardiovascular risk reduction in high-risk pediatric patients: a scientific statement from the American Heart Association Expert Panel on Population and Prevention Science; the Councils on Cardiovascular Disease in the Young, Epidemiology and Prevention, Nutrition, Physical Activity and Metabolism, High Blood Pressure Research, Cardiovascular Nursing, and the Kidney in Heart Disease; and the Interdisciplinary Working Group on Quality of Care and Outcomes Research

Although for most children the process of atherosclerosis is subclinical, dramatically accelerated atherosclerosis occurs in some pediatric disease states, with clinical coronary events occurring in childhood and very early adult life. As with most scientific statements about children and the future risk for cardiovascular disease, there are no randomized trials documenting the effects of risk reduction on hard clinical outcomes. A growing body of literature, however, identifies the importance of premature cardiovascular disease in the course of certain pediatric diagnoses and addresses the response to risk factor reduction. For this scientific statement, a panel of experts reviewed what is known about very premature cardiovascular disease in 8 high-risk pediatric diagnoses and, from the science base, developed practical recommendations for management of cardiovascular risk.

Kawasaki disease

Kawasaki disease is an acute febrile, systemic vasculitic syndrome of an unknown etiology that primarily occurs in children younger than five years of age. The principal presentations of Kawasaki disease include fever, bilateral nonexudative conjunctivitis, erythema of the lips and oral mucosa, changes in the extremities, rash, and cervical lymphadenopathy. Coronary artery aneurysms or ectasia develops in 15% to 25% of untreated children with the disease, which may later lead to myocardial infarction, sudden death, or ischemic heart disease. Treatment with intravenous gamma globulin (IVIG) is effective, but the mode of action is still unclear. The development of a diagnostic test, a more specific therapy, and ultimately the prevention of this potentially fatal illness in children are all dependent upon the continued advances in determining the etiopathogenesis of this fascinating disorder.

Cardiovascular Risk Reduction in High-Risk Pediatric Patients

Although for most children the process of atherosclerosis is subclinical, dramatically accelerated atherosclerosis occurs in some pediatric disease states, with clinical coronary events occurring in childhood and very early adult life. As with most scientific statements about children and the future risk for cardiovascular disease, there are no randomized trials documenting the effects of risk reduction on hard clinical outcomes. A growing body of literature, however, identifies the importance of premature cardiovascular disease in the course of certain pediatric diagnoses and addresses the response to risk factor reduction. For this scientific statement, a panel of experts reviewed what is known about very premature cardiovascular disease in 8 high-risk pediatric diagnoses and, from the science base, developed practical recommendations for management of cardiovascular risk.

The concentration of apolipoprotein A-I decreases during experimentally induced acute-phase processes in pigs

In this work, apolipoprotein A-I (ApoA-I) was purified from pig sera. The responses of this protein after sterile inflammation and in animals infected with Actinobacillus pleuropneumoniae or Streptococcus suis were investigated. Decreases in the concentrations of ApoA-I, two to five times lower than the initial values, were observed at 2 to 4 days. It is concluded that ApoA-I is a negative acute-phase protein in pigs.

Diagnosis, treatment, and long-term management of Kawasaki disease: a statement for health professionals from the Committee on Rheumatic Fever, Endocarditis and Kawasaki Disease, Council on Cardiovascular Disease in the Young, American Heart Association

BACKGROUND

Kawasaki disease is an acute self-limited vasculitis of childhood that is characterized by fever, bilateral nonexudative conjunctivitis, erythema of the lips and oral mucosa, changes in the extremities, rash, and cervical lymphadenopathy. Coronary artery aneurysms or ectasia develop in approximately 15% to 25% of untreated children and may lead to ischemic heart disease or sudden death.

METHODS AND RESULTS

A multidisciplinary committee of experts was convened to revise the American Heart Association recommendations for diagnosis, treatment, and long-term management of Kawasaki disease. The writing group proposes a new algorithm to aid clinicians in deciding which children with fever for > or =5 days and < or =4 classic criteria should undergo echocardiography, receive intravenous gamma globulin (IVIG) treatment, or both for Kawasaki disease. The writing group reviews the available data regarding the initial treatment for children with acute Kawasaki disease, as well for those who have persistent or recrudescent fever despite initial therapy with IVIG, including IVIG retreatment and treatment with corticosteroids, tumor necrosis factor-alpha antagonists, and abciximab. Long-term management of patients with Kawasaki disease is tailored to the degree of coronary involvement; recommendations regarding antiplatelet and anticoagulant therapy, physical activity, follow-up assessment, and the appropriate diagnostic procedures to evaluate cardiac disease are classified according to risk strata.

CONCLUSIONS

Recommendations for the initial evaluation, treatment in the acute phase, and long-term management of patients with Kawasaki disease are intended to assist physicians in understanding the range of acceptable approaches for caring for patients with Kawasaki disease. The ultimate decisions for case management must be made by physicians in light of the particular conditions presented by individual patients.

Glucocorticoid use and serum lipid levels in US adults: The third national health and nutrition examination survey

OBJECTIVE

It has been generally perceived that glucocorticoids adversely affect serum lipid levels, although results of prospective studies have suggested the contrary. In this study, we sought to examine the relationship between glucocorticoid use and lipid profiles in a nationally representative sample of subjects.

METHODS

Using data from 15,004 participants ages 20 years and older in The Third National Health and Nutrition Examination Survey (1988-1994), we examined the relationship between glucocorticoid use and serum lipid profiles. Glucocorticoid use was determined from the household interview regarding prescription medication use. We used multivariate linear regression to adjust for age, sex, race or ethnicity, education, smoking status, body mass index, physical activity, alcohol consumption, energy fraction from protein and carbohydrates, and total energy intake.

RESULTS

Glucocorticoid use was associated with a higher serum high-density lipoprotein (HDL) cholesterol level and a lower ratio of total cholesterol-to-HDL cholesterol among subjects ages 60 years or older (multivariate difference 9.0 mg/dl [95% confidence interval (95% CI) 3.9, 14.1] and -0.6 mg/dl [95% CI -0.9, -0.3], respectively) but not among those younger than age 60 years (multivariate difference -1.5 mg/dl [95% CI -5.4, 2.5] and 0.1 mg/dl [95% CI -0.3, 0.5], respectively). Correspondingly, glucocorticoid use was associated with a higher serum apolipoprotein A-I (Apo A-I) level and a lower Apo A-I:Apo B ratio (multivariate difference 12.1 mg/dl [95% CI 2.9, 21.3] and 0.16 mg/dl [95% CI 0.03, 0.29], respectively) only among subjects ages 60 years or older. Inhalation/intranasal glucocorticoid use was also associated with a higher serum HDL cholesterol level (multivariate difference 4.9 mg/dl [95% CI 0.3, 9.5]) only among subjects ages 60 years or older.

CONCLUSION

Our results suggest that glucocorticoid use is not associated with an adverse lipid profile in the US population and may be associated with a favorable lipid profile among persons ages 60 years or older, in concordance with previous prospective studies.

Serum amyloid A binding to CLA-1 (CD36 and LIMPII analogous-1) mediates serum amyloid A protein-induced activation of ERK1/2 and p38 mitogen-activated protein kinases

Serum amyloid A protein (SAA) is an acute-phase reactant, known to mediate pro-inflammatory cellular responses. This study reports that CLA-1 (CD36 and LIMPII Analogous-1; human orthologue of the Scavenger Receptor Class B Type I (SR-BI)) mediates SAA uptake and downstream SAA signaling. Flow cytometry experiments revealed more than a 5-fold increase of Alexa-488 SAA uptake in HeLa cells stably transfected with CLA-1. Alexa 488-HDL uptake directly correlated with SAA uptake when determined in several CLA-1 stably transfected HeLa cell clones expressing various levels of CLA-1. SAA directly binds to CLA-1 as determined by cross-linking and colocalization of anti-CLA-1 antibody with SAA. SAA was co-internalized with transferrin to the endocytic recycling compartment pointing to a potential site of SAA metabolism. Alexa-488 SAA uptake in the CLA-1-overexpressing HeLa cells, as well as in THP-1 monocyte cell line, can be efficiently blocked by unlabeled SAA, high density lipoprotein, and other CLA-1 ligands. At the same time, markedly enhanced levels of phosphorylation of the mitogen-activated protein kinases (MAPKs), ERK1/2, and p38, were observed in cells stably transfected with CLA-1 cells following SAA stimulation when compared with mock transfected cells. The levels of the SAA-induced interleukin-8 (IL-8) secretion by CLA-1-overexpressing cells also significantly exceeded (5- to 10-fold) those detected for control cells. Synthetic amphipathic peptides possessing a structural alpha-helical motif inhibited SAA-induced activation of both MAPKs and IL-8 secretion in THP-1 cells. The results of this study demonstrate for the first time that CLA-1 functions as an endocytic SAA receptor and is involved in SAA-mediated cell signaling events associated with the immune-related and inflammatory effects of SAA.

Diagnosis, treatment, and long-term management of Kawasaki disease: a statement for health professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, American Heart Association

BACKGROUND

Kawasaki disease is an acute self-limited vasculitis of childhood that is characterized by fever, bilateral nonexudative conjunctivitis, erythema of the lips and oral mucosa, changes in the extremities, rash, and cervical lymphadenopathy. Coronary artery aneurysms or ectasia develop in approximately 15% to 25% of untreated children and may lead to ischemic heart disease or sudden death.

METHODS AND RESULTS

A multidisciplinary committee of experts was convened to revise the American Heart Association recommendations for diagnosis, treatment, and long-term management of Kawasaki disease. The writing group proposes a new algorithm to aid clinicians in deciding which children with fever for > or =5 days and < or =4 classic criteria should undergo echocardiography [correction], receive intravenous gamma globulin (IVIG) treatment, or both for Kawasaki disease. The writing group reviews the available data regarding the initial treatment for children with acute Kawasaki disease, as well for those who have persistent or recrudescent fever despite initial therapy with IVIG, including IVIG retreatment and treatment with corticosteroids, tumor necrosis factor-alpha antagonists, and abciximab. Long-term management of patients with Kawasaki disease is tailored to the degree of coronary involvement; recommendations regarding antiplatelet and anticoagulant therapy, physical activity, follow-up assessment, and the appropriate diagnostic procedures to evaluate cardiac disease are classified according to risk strata.

CONCLUSIONS

Recommendations for the initial evaluation, treatment in the acute phase, and long-term management of patients with Kawasaki disease are intended to assist physicians in understanding the range of acceptable approaches for caring for patients with Kawasaki disease. The ultimate decisions for case management must be made by physicians in light of the particular conditions presented by individual patients.

Low apolipoprotein A-I level at intensive care unit admission and systemic inflammatory response syndrome exacerbation*

OBJECTIVE

Examine whether a low serum level of apolipoprotein A-I at intensive care unit (ICU) admission is associated with a further increase of the number of systemic inflammatory response syndrome (SIRS) criteria.

DESIGN

Prospective observational study.

SETTING

A 20-bed, university-affiliated, surgical ICU.

PATIENTS

Patients admitted after major surgery, multiple trauma, or acute pancreatitis without septic shock.

INTERVENTIONS

We defined as the SIRS Exacerb group patients who presented a further increase of the number of SIRS criteria during their ICU stay or, in the presence of four SIRS criteria at ICU admission, those who presented a further aggravation of organ failure. Other patients were attributed to the SIRS No Exacerb group. From day 1 to 6, we measured apolipoprotein A-I, high-density lipoprotein and total cholesterol, triglycerides, C-reactive protein, procalcitonin, serum amyloid A, interleukin 6, interleukin-1 receptor antagonist, albumin, and other nutrition-linked variables. We looked at laboratory values or factors present at ICU admission according to the two groups.

MEASUREMENTS AND MAIN RESULTS

From 63 patients analyzed, 29 (46%) were assigned to the SIRS Exacerb group. Age, sex, and SAPS II and SIRS scores at ICU admission did not differ between the groups. Patients in the SIRS Exacerb group presented more often a septic event (5/29 vs. 0/34, p =.02), had a higher hospital mortality (6/29 vs. 0/34, p =.007), and had a longer ICU stay (p =.0023). At admission, inflammatory variables such as the C-reactive protein, serum amyloid A, interleukin 6, interleukin-1 receptor antagonist plasma levels, and other lipid or nutrition-linked variables were similar between the two groups. Apolipoprotein A-I levels were lower in the SIRS Exacerb group (median [interquartile range]: 68 [56-81] vs. 84 [69-94] mg/dL, p =.028).

CONCLUSION

A low serum level of apolipoprotein A-I at ICU admission is associated with an increase of the number of SIRS criteria during the ICU stay.

Novel and traditional cardiovascular risk factors in children after Kawasaki disease

OBJECTIVES

We determined the profile of cardiovascular risk factors in children late after Kawasaki disease (KD) and compared it with that of age-matched healthy children.

BACKGROUND

Concerns have been raised regarding the possibility of a predisposition of KD to premature atherosclerosis later in life.

METHODS

A cohort of 102 subjects were studied: 37 KD patients with coronary aneurysms (group I), 29 KD patients with normal coronary arteries (group II), and 36 healthy age-matched children (group III). The fasting total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein (apo) A-I, apoB, and homocysteine levels were compared among the three groups. In addition, blood pressure and brachioradial arterial stiffness, as determined by pulse wave velocity (PWV), were measured and compared.

RESULTS

Group I subjects had lower HDL cholesterol (p = 0.016) and apoA-I levels (p = 0.044) and higher apoB levels (p = 0.029) and PWV (p = 0.001) than group III control subjects. Likewise, the apoB levels (p = 0.007) and PWV (p = 0.042) were higher in group II than in III subjects, although their HDL cholesterol (p = 0.54) and apoA-I (p = 0.52) levels were similar. The LDL cholesterol levels were higher in group I and II patients than in controls, although not statistically significant (p = 0.17). Blood pressure and homocysteine levels did not differ among the groups.

CONCLUSIONS

An adverse cardiovascular risk profile, as characterized by a proatherogenic alteration of the lipid profile and increased arterial stiffness, occurs in children after KD. The profile is worse in those with than in those without coronary aneurysms.

Effects of antirheumatic therapy on serum lipid levels in patients with rheumatoid arthritis: a prospective study

BACKGROUND

Patients with newly diagnosed rheumatoid arthritis have adverse serum lipid profiles. We sought to determine the effects of treating rheumatoid arthritis with antirheumatic drugs on these abnormal lipid levels.

SUBJECTS AND METHODS

We studied 42 patients with newly diagnosed rheumatoid arthritis who had not been treated with corticosteroids or disease-modifying antirheumatic drugs. We measured serum lipid profiles at baseline and 1 year later, and determined whether there were differences in the changes in lipid levels between patients who met the American College of Rheumatology criteria for a 20% improvement in rheumatoid arthritis and those who did not.

RESULTS

Of the 42 patients, 27 (64%) met the criteria for a 20% improvement in rheumatoid arthritis during the 12-month study. In these patients, mean high-density lipoprotein (HDL) cholesterol levels increased by 21% (P <0.001), apolipoprotein A-I levels increased by 23% (P <0.001), and the ratio of low-density lipoprotein (LDL) cholesterol to HDL cholesterol level decreased by 13% (P = 0.10). There were significant between-group differences (responders-nonresponders) in the mean 12-month changes in HDL cholesterol levels (8.0 mg/dL; 95% confidence interval [CI]: 3 to 13 mg/dL; P = 0.002), apolipoprotein A-I levels (21 mg/dL; 95% CI: 8 to 33 mg/dL; P = 0.003), and the LDL cholesterol to HDL cholesterol ratio (-0.6; 95% CI: -0.1 to -1.0; P = 0.03), but not in LDL cholesterol, apolipoprotein B-100, or lipoprotein(a) levels.

CONCLUSION

Active rheumatoid arthritis is associated with an adverse lipid profile that improves substantially following effective treatment of rheumatoid arthritis. This improvement may reduce the risk of cardiovascular disease.

Serum amyloid A and high-density lipoprotein cholesterol: serum markers of inflammation in sarcoidosis and other systemic disorders

Hypocholesterolemia has been observed in several inflammatory diseases such as rheumatoid arthritis, myeloproliferative disorders, systemic lupus erythematosus and sarcoidosis. Serum amyloid A is an acute-phase reactant that is related to the high-density lipoprotein cholesterol. This review discusses the relationship between the activation of the cells of the monocyte-macrophage system, determined by the serum amyloid A levels, and the lipid metabolism, measured as alterations in plasma lipoprotein concentrations. The mechanisms of this association during acute inflammation are also discussed in this review.

Cardiovascular risk factors after Kawasaki disease: a case-control study

OBJECTIVES

To determine cardiovascular risk profiles of patients with Kawasaki disease and to relate them to a noninvasive measure of endothelial function.

STUDY DESIGN

Case-control study. Cardiovascular risk assessment including brachial artery reactivity was performed in 24 patients 11.3 +/- 1.8 (mean +/- SD) years after Kawasaki disease and in 11 subjects in a normal control group.

RESULTS

The case versus control groups were similar regarding age, sex, race, body mass index, and percentage of ideal body weight, although cases had a higher mean z score of body mass index than normal (+1.00 +/- 1.18; P <.001). Cases had normal fasting total cholesterol levels but a higher mean z score of triglyceride levels (+1.35 +/- 2.04; P <.004). The case group had significantly higher mean systolic and diastolic resting blood pressure z scores (+0.76 +/- 1.06; P <.01 and +0.96 +/- 1.19; P <.01, respectively) than the control group and population norms. Endothelial function as indicated by brachial artery reactivity was not significantly different between the case versus control groups. In the case group higher blood pressure, increasing adiposity, and higher fasting triglyceride levels were significantly interrelated but did not relate to brachial artery reactivity or coronary artery abnormalities.

CONCLUSIONS

Patients after Kawasaki disease tend to have a more adverse cardiovascular risk profile potentially indicative of an increased predisposition to premature atherosclerotic changes.

Influence of serum amyloid A on the decrease of high density lipoprotein-cholesterol in active sarcoidosis

OBJECTIVE

We have previously observed low levels of high density lipoprotein (HDL) cholesterol in active sarcoidosis. The aim of this study was to analyze the role of serum amyloid A (SAA) on this lipid disorder.

METHODS

Eighty five untreated sarcoid patients, 40 with active disease and 45 with inactive disease, were recruited. Sarcoidosis activity was evaluated by means of clinical, chest X-ray, gallium-67 scan, serum angiotensin converting enzyme (peptidyl-dipeptidase A) values, and pulmonary function tests. Analysis of lipoprotein metabolism included: serum cholesterol, low density lipoprotein (LDL)-cholesterol, HDL-cholesterol, HDL(2)-cholesterol, HDL(3)-cholesterol, apolipoprotein A-I (apo A-I), apolipoprotein B (apo B), and triglyceride concentrations. Serum amyloid A protein and lecithin-cholesterol acyltransferase (LCAT) activity were measured.

RESULTS

In active sarcoidosis we found significantly reduced levels of HDL-cholesterol (1.17+/-0.36 vs. 1. 44+/-0.39 mmol/l, P=0.002), HDL(3)-cholesterol (0.78+/-0.23 vs. 1. 02+/-0.21 mmol/l, P<0.0001), and apo A-I (1.36+/-0.29 vs. 1.61+/-0. 27 g/l, P<0.0001) and significantly increased levels of triglyceride (1.51+/-0.64 vs. 1.03+/-0.46 mmol/l, P<0.0001), and apo B (1.14+/-0. 25 vs. 0.99+/-0.27 g/l, P=0.012) versus inactive sarcoidosis. Serum amyloid A concentrations were significantly increased in the patients with active disease (155.45+/-154.01 mg/ml) compared to the inactive sarcoid patients (89.70+/-65.36 mg/ml) (P=0.011). There were no significant differences in cholesterol, LDL-cholesterol, HDL(2)-cholesterol or LCAT values between groups. Multivariate logistic regression analysis showed that HDL-cholesterol (regression coefficient b=-1.96; S.E.=0.87; P=0.02) and SAA (regression coefficient b=0.01; S.E.=0.004; P=0.01) were the two variables independently associated with disease activity. Moreover, a significant negative correlation was observed between SAA levels and both HDL-cholesterol (r=-0.39; P=0.01) and apo A-I (r=-0.35; P=0.03) levels, in the active sarcoid group. Conversely, no correlation was found in the inactive sarcoid group.

CONCLUSION

The low HDL-cholesterol and apo A-I concentrations seen in active sarcoid patients are associated with a significant increase of SAA levels. We suggest that the displacement of apo A-I by SAA on HDL accounts for the lower level of HDL-cholesterol seen in active sarcoidosis.

Role of serum amyloid A during metabolism of acute-phase HDL by macrophages

The serum amyloid A (SAA) family of proteins is encoded by multiple genes that display allelic variation and a high degree of homology in mammals. Triggered by inflammation after stimulation of hepatocytes by lymphokine-mediated processes, the concentrations of SAA may increase during the acute-phase reaction to levels 1000-fold greater than those found in the noninflammatory state. In addition to its role as an acute-phase reactant, SAA (104 amino acids, 12 kDa) is considered to be the precursor protein of secondary reactive amyloidosis, in which the N-terminal portion is incorporated into the bulk of amyloid fibrils. However, the association with lipoproteins of the high-density range and subsequent modulation of the metabolic properties of its physiological carrier appear to be the principal role of SAA. Because SAA may displace apolipoprotein A-I, the major protein component of native high density lipoprotein (HDL), during the acute-phase reaction, the present study was aimed at (1) investigating binding properties of native and acute-phase (SAA-enriched) HDL by J774 macrophages, (2) elucidating whether the presence of SAA on HDL particles affects selective uptake of HDL-associated cholesteryl esters, and (3) comparing cellular cholesterol efflux mediated by native and acute-phase HDL. Both the total and the specific binding at 4 degrees C of rabbit acute-phase HDL were approximately 2-fold higher than for native HDL. Nonlinear regression analysis revealed K(d) values of 7.0 x 10(-7) mol/L (native HDL) and 3.1 x 10(-7) mol/L (acute-phase HDL), respectively. The corresponding B(max) values were 203 ng of total lipoprotein per milligram of cell protein (native HDL) and 250 ng of total lipoprotein per milligram of cell protein (acute-phase HDL). At 37 degrees C, holoparticle turnover was slightly enhanced for acute-phase HDL, a fact reflected by 2-fold higher degradation rates. In contrast, the presence of SAA on HDL specifically increased (1. 7-fold) the selective uptake of HDL cholesteryl esters from acute-phase HDL by J774 macrophages, a widely used in vitro model to study foam cell formation and cholesterol efflux properties. Although ligand blotting experiments with solubilized J774 membrane proteins failed to identify the scavenger receptor-BI as a binding protein for both native and acute-phase HDL, 2 binding proteins with molecular masses of 100 and 72 kDa, the latter comigrating with CD55 (also termed decay-accelerating factor), were identified. During cholesterol efflux studies, it became apparent that the ability of acute-phase HDL with regard to cellular cholesterol removal was considerably lower than that for native HDL. This was reflected by a 1.7-fold increase in tau/2 values (22 versus 36 hours; native versus acute-phase HDL). Our observations of increased HDL cholesteryl ester uptake and reduced cellular cholesterol efflux (acute-phase versus native HDL) suggest that displacement of apolipoprotein A-I by SAA results in considerable altered metabolic properties of its main physiological carrier. These changes in the apolipoprotein moieties appear (at least in the in vitro system tested) to transform an originally antiatherogenic into a proatherogenic lipoprotein particle.

Kawasaki syndrome

Kawasaki syndrome is a fascinating worldwide illness of young children. This acute self-limited vasculitis has become the most common cause of acquired heart disease in children in the United States and Japan. KS causes significant coronary artery disease that may lead to myocardial infarction and sudden death. Clinical and epidemiologic features of KS support an infectious cause, but the etiology remains unknown. Clearly, additional research on the cause of KS and its pathogenesis is needed urgently to allow for improved diagnosis; more specific therapy; and, ultimately, prevention of the disorder.