Generation of C-reactive protein and complement components in atherosclerotic plaques

Aspirin resistance following pediatric cardiac surgery

INTRODUCTION

Aspirin is often used to prevent thrombosis in pediatric cardiac surgery. The primary study aim was to assess aspirin resistance in this context. Secondary aims were to evaluate (1) the relationship between elevated inflammatory markers and thrombosis and (2) aspirin's effect on these levels.

MATERIALS AND METHODS

This was a prospective observational study of children undergoing cardiac surgery managed with and without aspirin. Aspirin response was assessed using the VerifyNow system and urinary 11-dehydrothromboxane B2 (uTxB2) measurements. Laboratory studies of inflammation were also obtained.

RESULTS

101 subjects were studied; 50 received aspirin. Six subjects (5.9%), 5 aspirin-treated, experienced symptomatic thrombosis. When measured by VerifyNow resistance was 43% after aspirin suppositories and 14% after additional days of oral aspirin. There was no correlation with thrombosis. Upper quartile post-operative day (POD) #5 uTxB2 was correlated with thrombosis in aspirin treated subjects (p<0.01). High risk aspirin-treated subjects who experienced thrombosis had higher POD#5 uTxB2. This finding did not reach statistical significance (p=0.07). Elevated pre-operative C-reactive protein (CRP) was independently associated with thrombosis (p<0.02) in all subjects and in high risk subjects (p=0.01). Inflammatory markers were not affected by aspirin.

CONCLUSIONS

Aspirin inhibited ex-vivo platelet function with a low incidence of resistance. Elevated POD#5 uTxB2 and pre-operative CRP were correlated with thrombosis in aspirin treated subjects. Further studies are needed to determine whether children with high levels of uTxB2 despite aspirin therapy and/or those with elevated preoperative CRP are at increased risk for thrombosis.

Angiotensin II induces C-reactive protein expression through ERK1/2 and JNK signaling in human aortic endothelial cells

BACKGROUND

Atherosclerosis is an inflammatory disease in the vessel. As an inflammatory cytokine, C-reactive protein (CRP) participates in atherogenesis. Although angiotensin II (AngII) is known to evoke inflammatory response in vascular endothelial cells (VECs), there is no direct evidence to demonstrate the proinflammatory effect of AngII on VECs through CRP. The present study focused on effect of AngII on CRP expression and the signal pathway in human aortic endothelial cells (HAECs).

METHODS AND RESULTS

mRNA and protein expression was identified by RT-PCR and Western blot, respectively. Reactive oxygen species (ROS) were observed by a fluorescence microscope. The results showed that AngII significantly increased mRNA and protein expression of CRP in HAECs in time- and concentration-dependent ways. Anti-IL-1beta and anti-IL-6 neutralizing antibodies did not affect AngII-induced CRP expression. Losartan reduced AngII-induced CRP expression in mRNA and protein levels in HAECs. Losartan and TIFA decreased AngII-stimulated ROS generation, and antioxidant NAC completely abolished AngII-induced CRP expression in HAECs. The further study indicated that losartan, NAC, PD98059, SP600125 significantly inhibited ERK1/2 and JNK phosphorylation, and PD98059, SP600125, PDTC completely antagonized AngII-induced CRP expression in HAECs.

CONCLUSIONS

The present study demonstrates that AngII has ability to induce CRP expression in HAECs through AT(1)-ROS-ERK1/2 and JNK-NF-kappaB signal pathway, which strengthens understanding of the proinflammatory and proathroscerotic actions of AngII.

High-sensitivity C-reactive protein predicts cardiovascular risk in diabetic and nondiabetic patients: effects of insulin-sensitizing treatment with pioglitazone

Systemic inflammatory activity has turned out to play a key pathogenic role in vascular atherosclerosis, insulin resistance, and type 2 diabetes mellitus. Inflammatory biomarkers may therefore be a valuable tool for risk evaluation. Among them, the best evidence to date supports the use of high-sensitivity C-reactive protein (hs-CRP) to monitor insulin resistance and cardiovascular risk in diabetic and nondiabetic individuals. Data suggest that hs-CRP may also participate directly in the process of atherogenesis. A growing number of clinical trials tested the hypothesis that antidiabetic drugs specifically targeting insulin resistance could benefit individuals by reducing inflammation, atherogenesis, and thus cardiovascular risk. One such class are the thiazolidinediones (pioglitazone and rosiglitazone). These agents act as selective ligands of the nuclear transcription factor peroxisome proliferator-activated receptor-gamma (PPARgamma). This article reviewed published data on hs-CRP changes with the thiazolidinedione agent pioglitazone. Here we found pronounced insulin-sensitizing and anti-inflammatory properties in different clinical settings, including diabetic and nondiabetic individuals. Coadministration of pioglitazone to antilipidemic statin therapy resulted in additional effects on low-grade inflammation, and hs-CRP reduction has been demonstrated to occur independently of glucose lowering. The anti-inflammatory effect appeared to be a rapid physiologic reaction on PPARgamma activation and could be observed within a short-term interval after starting pioglitazone therapy. In summary, clinical study results underline the benefit of an early insulin resistance treatment to oppose systemic vascular inflammation and cardiometabolic syndrome in patients with elevated levels of high-sensitivity C-reactive protein.

Preoperative C-reactive protein predicts long-term mortality and hospital length of stay after primary, nonemergent coronary artery bypass grafting

BACKGROUND

Preoperative C-reactive protein (CRP) levels more than 10 mg/l have been shown to be associated with increased morbidity and mortality after cardiac surgery. We examine the value of preoperative CRP levels less than 10 mg/l for predicting long-term, all-cause mortality and hospital length of stay in surgical patients undergoing primary, nonemergent coronary artery bypass graft-only surgery.

METHODS

We examined the association between preoperative CRP levels stratified into four categories (< 1, 1-3, 3-10, and > 10 mg/l), and 7-yr all-cause mortality and hospital length of stay in 914 prospectively enrolled primary, nonemergent coronary artery bypass graft-only surgical patients using a proportional hazards regression model.

RESULTS

Eighty-seven patients (9.5%) died during a mean follow-up period of 4.8 +/- 1.5 yr. After proportional hazards adjustment, the 3-10 and > 10 mg/l preoperative CRP groups were associated with long-term, all-cause mortality (hazards ratios [95% CI]: 2.50 [1.22-5.16], P = 0.01 and 2.66 [1.21-5.80], P = 0.02, respectively) and extended hospital length of stay (1.32 [1.07-1.63], P < 0.001 and 1.27 [1.02-1.62], P = 0.001, respectively).

CONCLUSION

We demonstrate that preoperative CRP levels as low as 3 mg/l are associated with increased long-term mortality and extended hospital length of stay in relatively lower-acuity patients undergoing primary, nonemergent coronary artery bypass graft-only surgery. These important findings may allow for more objective risk stratification of patients who present for uncomplicated surgical coronary revascularization.

Predictive value of C-reactive protein after drug-eluting stent implantation

During the last few decades, with the evolution of techniques and materials and the increasing experience of operators, percutaneous coronary interventions (PCI) have become an equally efficient alternative to coronary artery bypass grafts for the treatment of most coronary stenoses. Bare-metal stent implantation represented a major step forward, compared with plain old balloon angioplasty (POBA), by improving the immediate angiographic success. However, the incidence of in-stent restenosis (ISR) remained unacceptably high. Development of the drug-eluting stent (DES) significantly improved the outcome of PCI by dramatically abating the rate of ISR and reducing the incidence of target lesion revascularization. However, ISR has not been eliminated and the persistence of metal vessel scaffolding also raises concern regarding the occurrence of late or very late stent thrombosis. POBA and stent implantation have been shown to induce a local and systemic inflammatory response, whose magnitude is associated with worse clinical outcome, and they increase the risk of ISR. C-reactive protein, a marker of systemic inflammation, has been demonstrated to predict clinical and angiographic outcome after POBA or bare-metal stent implantation. However, conflicting data regarding the prognostic value of C-reactive protein following DES implantation are available. In this paper, we review the literature regarding the clinical and pathophysiological association between inflammation and prognosis after DES implantation and suggest some possible therapeutic approaches to reduce inflammatory burden with the aim to improve clinical and angiographic outcome after PCI.

Novel markers of peripheral arterial disease

Peripheral arterial disease (PAD), a relatively common manifestation of atherosclerotic vascular disease, is associated with significant morbidity and mortality. Although conventional risk factors contribute to the onset and progression of PAD, the role of 'novel' biomarkers in pathways of inflammation, thrombosis, lipoprotein metabolism, and oxidative stress in determining susceptibility to PAD is being increasingly recognized. Validation of novel risk factors for PAD may allow earlier detection, an improved understanding of disease etiology and progression, and the development of new therapies. In this review, we discuss available evidence for associations between novel circulating markers and several aspects of PAD including disease susceptibility, progression, functional limitation, and adverse outcomes.

Inflammatory markers in schizophrenia: comparing antipsychotic effects in phase 1 of the clinical antipsychotic trials of intervention effectiveness study

BACKGROUND

C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin are systemic inflammatory markers (IM) that positively correlate with cardiovascular (CV) risk. Despite the known CV effects of atypical antipsychotics, there is limited prospective data on IM changes during treatment.

METHODS

The IM outcomes were compared between antipsychotic treatment groups in the CATIE (Clinical Antipsychotic Trials of Intervention Effectiveness) schizophrenia trial phase 1 with subjects with laboratory assessments at baseline and 3 months (n = 789).

RESULTS

There were significant treatment differences in CRP, E-selectin, and ICAM-1 at 3 months, with a differential impact of baseline values on the CRP and ICAM-1 results. In overall comparisons, quetiapine and olanzapine had the highest median levels for CRP, and olanzapine for E-selectin and ICAM-1. Olanzapine was significantly different after baseline adjustment than perphenazine (p = .001) for E-selectin, and in those with low baseline CRP (<1 mg/L), olanzapine was significantly different than perphenazine (p < .001), risperidone (p < .001), and ziprasidone (p = .002) for CRP. Perphenazine had the lowest 3-month ICAM-1 levels in subjects with baseline ICAM-1 above the median, but the differences were not statistically significant versus olanzapine (p = .010), quetiapine (p = .010), and risperidone (p = .006) after controlling for multiple comparisons. The 18-month repeated measures CRP analysis confirmed the significantly higher values for olanzapine in those with low baseline CRP.

CONCLUSIONS

This analysis provides further evidence for differential antipsychotic metabolic liabilities as measured by changes in systemic inflammation. C-reactive protein might emerge as a useful target for CV risk outcomes in schizophrenia patients.

Change in high-sensitive C-reactive protein during abdominal aortic aneurysm formation

OBJECTIVES

We try to clear the relationship between high-sensitive C-reactive protein (hsCRP) release and abdominal aortic aneurysm formation.

METHODS AND RESULTS

A rabbit abdominal aortic aneurysm model was created by elastase perfusion. At days 10, 20, and 30 after elastase perfusion, mean serum hsCRP levels detected by ELISA increased over 200% over their basal level (n = 11, P < 0.05). Serum hsCRP levels were significantly higher in the aneurysm groups than in the sham controls by day 5 (n = 11, P < 0.05) and were positively correlated with percentage vessel diameter changes in the aneurysm group by day 10 (r = 0.8012, n = 33, P < 0.05). In the aneurysm group, increased serum CRP was derived from the liver in early stages, yet from dilated vessels in the later stages, as shown by immunostaining, western blot, and reverse transcriptase-PCR. Similar increased hsCRP levels were also observed in dissected rabbit aortic ring explants from the aneurysm model. Pretreatment with the stretch-activated channel blockers gadolinium or streptomycin, as well as nuclear factor-kappaB inhibitor SN50, blocked hsCRP production in the dilated aortic rings. Stretch-activated channel blockers also inhibited the activation of nuclear factor-kappaB.

CONCLUSION

During abdominal aortic aneurysm formation, increased serum hsCRP levels derive from aneurysmal arteries with degenerating elastic lamina. This process is mediated by mechanical stretch-activated channel-dependent nuclear factor-kappaB translocation to the nucleus.

Association of inflammatory markers with angiographic severity and extent of coronary artery disease

Inflammatory processes play a pivotal role in the pathogenesis of atherosclerosis and mediate many of the stages of atheroma development, from initial leukocyte recruitment to eventual rupture of the unstable atherosclerotic plaque. Several systemic inflammatory markers reflect different degrees of inflammation and have been indicated as independent risk factors in cardiovascular disease, especially in unstable coronary syndromes. However, whether elevated levels of circulating inflammatory markers play a role in the extent and severity of atherosclerosis remains controversial. The present review summarizes our current understanding of the relationship between inflammatory markers and the presence and extent of coronary atherosclerosis, in order to assess the potential utility of these markers in identifying patients with higher levels of atherosclerotic burden.

Monomeric CRP contributes to complement control in fluid phase and on cellular surfaces and increases phagocytosis by recruiting factor H

Complement forms the first defense line of innate immunity and has an important role in the non-inflammatory clearance of apoptotic and necrotic cells. Factor H is one essential complement inhibitor that binds to the acute phase reactant C-reactive protein (CRP). By using recombinant proteins, calcium-independent binding of Factor H to monomeric CRP (mCRP), but not to pentameric CRP (pCRP), was shown. In addition to the two known CRP-binding sites, a novel third site was localized within the C-terminus. This region is frequently mutated in the hemolytic uremic syndrome and the mutant proteins show reduced mCRP binding. In this study, we show that mCRP directs Factor H to the surface of apoptotic and necrotic endothelial cells and identify phosphocholine as one binding moiety for this complex. Factor H-mCRP complexes enhance C3b inactivation both in the fluid phase and on the surface of damaged cells and inhibit the production of pro-inflammatory cytokines. By recruiting the soluble complement inhibitor Factor H to the surface of damaged cells, mCRP blocks the progression of the complement cascade beyond the step of the C3 convertase, prevents the formation of inflammatory activation products, and thus contributes to the safe removal of opsonized damaged cells and particles.

Urinary proteins in children with urinary tract infection

The aim of this study was to test our hypothesis that the urinary excretion of C-reactive protein (CRP), alpha 1-microglobulin (A1M), retinol-binding protein (RBP) and Clara cell protein (CC16) is increased in children with urinary tract infection (UTI) and relates to renal damage as measured by acute dimercaptosuccinic acid (DMSA) scintigraphy. Fifty-two children <2 years of age with UTI were enrolled in the study, 44 of whom were febrile. The control group consisted of 23 patients with non-UTI infection and elevated serum CRP (s-CRP) levels. Thirty-six patients had abnormal DMSA uptake, classified as mild, moderate or severe damage (DMSA class 1, 2, 3, respectively). There was a significant association between DMSA class and the excretion of urinary RBP (u-RBP) and u-CC16. There was also a significant difference in u-CRP levels between children with UTI and control children with non-UTI infections, although u-CRP excretion was not significantly correlated to DMSA class. In conclusion, the urinary excretion of the low-molecular-weight proteins RBP and CC16 showed a strong association with uptake defects on renal DMSA scans. The urinary level of CRP seems to distinguish between children with UTI and other febrile conditions. A combination of these biomarkers may be useful in the clinical assessment of children with UTI.

Dissociation of Pentameric to Monomeric C-Reactive Protein on Activated Platelets Localizes Inflammation to Atherosclerotic Plaques

C-reactive protein (CRP) is a predictor of cardiovascular risk. It circulates as a pentamer (pentameric CRP) in plasma. The in vivo existence of monomeric (m)CRP has been postulated, but its function and source are not clear. We show that mCRP is deposited in human aortic and carotid atherosclerotic plaques but not in healthy vessels. pCRP is found neither in healthy nor in diseased vessels. As source of mCRP, we identify a mechanism of dissociation of pCRP to mCRP. We report that activated platelets, which play a central role in cardiovascular events, mediate this dissociation via lysophosphatidylcholine, which is present on activated but not resting platelets. Furthermore, the dissociation of pCRP to mCRP can also be mediated by apoptotic monocytic THP-1 and Jurkat T cells. The functional consequence is the unmasking of proinflammatory effects of CRP as demonstrated in experimental settings that are pathophysiologically relevant for atherogenesis: compared to pCRP, mCRP induces enhanced monocyte chemotaxis; monocyte activation, as determined by conformational change of integrin Mac-1; generation of reactive oxygen species; and monocyte adhesion under static and physiological flow conditions. In conclusion, we demonstrate mCRP generation via pCRP dissociation on activated platelets and H 2 O 2 -treated apoptotic THP-1 and Jurkat T cells, thereby identifying a mechanism of localized unmasking of the proinflammatory properties of CRP. This novel mechanism provides a potential link between the established cardiovascular risk marker, circulating pCRP, and localized platelet-mediated inflammatory and proatherogenic effects.

Local C-reactive protein expression in obliterative lesions and the bronchial wall in posttransplant obliterative bronchiolitis

The local immunoreactivity of C-reactive protein (CRP) was studied in a heterotopic porcine model of posttranplant obliterative bronchiolitis (OB). Bronchial allografts and control autografts were examined serially 2–28 days after subcutaneous transplantation. The autografts stayed patent. In the allografts, proliferation of inflammatory cells (P < .0001) and fibroblasts (P = .02) resulted in occlusion of the bronchial lumens (P < .01). Influx of CD4+ (P < .001) and CD8+ (P < .0001) cells demonstrated allograft immune response. CRP positivity simultaneously increased in the bronchial walls (P < .01), in macrophages, myofibroblasts, and endothelial cells. Local CRP was predictive of features characteristic of OB (R = 0.456–0.879, P < .05−P < .0001). Early obliterative lesions also showed CRP positivity, but not mature, collagen-rich obliterative plugs (P < .05). During OB development, CRP is localized in inflammatory cells, myofibroblasts and endothelial cells probably as a part of the local inflammatory response.

CRP and the risk of atherosclerotic events

A large body of literature supports the idea that inflammation plays a pivotal role in all phases of atherosclerosis, from the fatty streak lesion formation to the acute coronary event due to vulnerable plaque rupture. Indeed, vascular inflammation contributes to the pathogenesis of atherosclerosis, and later in the disease process, it is a major determinant for the acute coronary syndromes. There are various inflammatory markers that have been shown to predict cardiovascular events. These include high-sensitivity C-reactive protein (hs-CRP), a simple downstream marker of inflammation, recently emerged as a major cardiovascular risk factor. Elevated baseline concentrations of hs-CRP are associated with the risk of atherosclerotic events in general populations and show a predictive value even in terms of secondary prevention, both in patients with chronic stable angina and acute coronary syndromes. In recent year, a lot of concerns have emerged about the experimental models used to study the role of CRP in atherosclerosis; moreover, the results of trials evaluating the clinical association between this molecules and outcome are still controversial. In this paper, we attempt to review the pathophysiological evidences about the link between CRP and atherosclerosis and, most notably, about its utility as a marker and risk predictor in various clinical settings. The identification of specific triggers and mechanisms of underlying inflammation and a better understanding of each step involved in this complex process might lead to new ways to manage patients with atherosclerosis, both in terms of primary and secondary prevention, and CRP still appears to be a suitable candidate for this purpose.

Multimarker approach predicts adverse cardiovascular events in women evaluated for suspected ischemia: results from the National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation

BACKGROUND

Inflammatory marker and hemoglobin levels (eg biomarkers) considered separately, predict adverse events in selected populations.

HYPOTHESIS

A multiple biomarker approach predicts adverse events in women referred for evaluation of ischemia.

METHODS

We investigated associations between biomarkers (high sensitivity C-reactive protein, interleukin-6, serum amyloid-A, and hemoglobin levels) with adverse outcomes in women referred for coronary angiography for suspected ischemia in the National Heart, Lung, and Blood Institute (NHLBI)-sponsored Women's Ischemia Syndrome Evaluation (WISE).

RESULTS

Among 595 women (mean age 58 years, ejection fraction [EF] 65%, majority without coronary stenosis >or= 50%) followed for 3.6 +/- 1.8 years (mean +/- SD), those without abnormal markers had fewer events (11.6%) compared to those with 1 (18.4%), 2 (20.9%), or 3 (37%) abnormal markers (p < 0.001 for trend). Women without abnormal markers had fewer deaths (1.6%) than women with 1 (6.1%), 2 (9.1%), or 3 (17%) abnormal markers (p < 0.001 for trend). Adding low hemoglobin was associated with higher adverse event and all-cause mortality rates. In multivariate analysis, as the number of abnormal biomarkers increased risk increased. Women with 3 or 4 abnormal biomarkers were approximately 10-20 times more likely to die (p < 0.05). Biomarkers added to the predictive information provided by the Framingham Risk Score.

CONCLUSIONS

Among women undergoing coronary angiography for suspected ischemia, a multibiomarker approach predicted adverse events. Biomarkers added prognostic information beyond that obtained from traditional risk factors.

Inflammation as a cardiovascular risk factor and pulse wave velocity as a marker of early-stage atherosclerosis in the Japanese population

Inflammation and pulse wave velocity (PWV) are a potential risk factor and marker, respectively, for atherosclerosis in the primary prevention setting. Atherosclerosis is now generally accepted to be an inflammatory disorder of the arterial wall, and the high-sensitivity C-reactive protein (hs-CRP) level has been reported to be a strong predictor of cardiovascular events. High-sensitivity-CRP is associated with two factors related to inflammation: (1) the local production of CRP by atheromatous tissue or coronary artery smooth muscle cells and (2) adipose tissue as a potent source of inflammatory cytokines. Based on studies in North America and Europe, hs-CRP has been established as a cardiovascular risk factor and a cut-off value has been recommended. However, Japanese have lower hs-CRP values than their Western counterparts, partly because Japanese have a lower body mass index (BMI), which correlates positively to hs-CRP, and partly because lifestyle and genetic factors can affect hs-CRP values. Therefore, a cut-off value needs to be established by cohort studies for the Japanese population. Carotid-femoral PWV is most commonly measured by applanation tonometry, particularly in Europe, but this method is critically dependent upon the accurate placing of transducers over the arteries and is both time-consuming and complex. A novel device has been recently developed in Japan that measures brachial-ankle PWV (baPWV) using a volume-rendering method. Brachian-ankle PWV is a suitable screening method because of its technical simplicity and shorter measurement time. It is associated not only with conventional cardiovascular risk factors but also with new risk factors, such as inflammation, gamma-glutamyltransferase, chronic kidney disease, and psychosocial factors. However, a suitable cut-off value has yet to be established.

Genetics of C-reactive protein and complement factor H have an epistatic effect on carotid artery compliance: the Cardiovascular Risk in Young Finns Study

Atherosclerosis is characterized by a prominent inflammatory component and C-reactive protein (CRP) has been implicated to modulate the complement activity in atherosclerotic arteries via complement factor H (CFH) binding. In this study, we examined whether the gene-gene interactions between CRP haplotypes and CFH Tyr402His functional polymorphism exerted an effect on early atherosclerosis. Single nucleotide polymorphisms (SNPs) in CFH (Tyr402His) and CRP (-717A>G, -286C >T>A, +1059G>C, +1444C>T and +1846G>A) were genotyped in the participants of the Cardiovascular Risk in Young Finns Study (n=1698, aged 24-39 years). The CRP SNPs were further constructed into haplotypes and their interactive effects with the CFH Tyr402His polymorphism on the early atherogenic vascular changes [i.e. carotid artery compliance (CAC) and intima-media thickness (IMT)] were examined. After risk factor adjustment, a significant gene-gene interaction (P=0.007) on CAC was observed between CRP haplotype ATGTG and CFH Tyr402His polymorphism in males. Furthermore, logistic regression analysis verified the risk-modifying interactive effect on CAC between these loci (OR 3.70, 95% CI 1.37-10.02, P=0.010). No effects on CAC were observed in females and no effects on IMT were detected in either sex. We conclude that the combined presence of CRP haplotype ATGTG and CFH 402His allele may be disadvantageous to carotid artery elasticity in males.

C-reactive protein (CRP) up-regulates expression of receptor for advanced glycation end products (RAGE) and its inflammatory ligand EN-RAGE in THP-1 cells: inhibitory effects of atorvastatin

BACKGROUND

Receptor for advanced glycation end products (RAGE) may play an important role in inflammatory processes and endothelial activation. Extracellular newly identified RAGE binding protein (EN-RAGE), natural pro-inflammatory ligand for RAGE. The role of C-reactive protein (CRP) as a mediator in inflammation and atherosclerosis is the subject of recent investigations worldwide. In the present study, we investigated the effect of CRP on RAGE and EN-RAGE gene expression in THP-1 monocytic cell line. MAP kinases (ERK, p38 and JNK) were exploited as possible signaling pathways involved in the signal transduction by CRP. Further, atorvastatin was used as a therapeutic modality for modulation of these genes in the presence of CRP.

MATERIALS AND METHODS

Time and dose-dependent experiments were carried out in the presence of CRP. Specific MAPK pathways inhibitors were used to elucidate the signaling pathways involved. Effect of atorvastatin was also determined in the presence of CRP on the expression of these genes.

RESULTS

Time and dose-dependent experiments revealed that, treatment of THP-1 cells with 100 microg of CRP/ml/10(6) cells for 24 h, augmented the expression of RAGE and EN-RAGE genes by 2.5-3.5 folds and 3.5-4.5 folds respectively. CRP acted via FcgammaRII and utilized ERK, p38 and JNK pathways to transduce signals. Atorvastatin in a dose of 20 muM, was able to attenuate up-regulation of CRP-induced genes (p<0.01) and effects were both dose and time-dependent.

CONCLUSION

Our data strongly suggests that blockade of RAGE-EN-RAGE by statins at an early stage may prevent inflammation in atherosclerosis and counteract the harmful effects mediated by CRP.

The evolving role of C-reactive protein in atherothrombosis

BACKGROUND

Inflammation is pivotal in all phases of atherosclerosis. Among the numerous inflammatory biomarkers, the largest amount of published data supports a role for C-reactive protein (CRP) as a robust and independent risk marker in the prediction of primary and secondary adverse cardiovascular events. In addition to being a risk marker, there is much evidence indicating that CRP may indeed participate in atherogenesis.

CONTENT

In this review, we focus on the role of CRP in promoting atherothrombosis by discussing its effects on endothelial cells, endothelial progenitor cells, monocyte-macrophages, and smooth muscle cells.

CONCLUSIONS

CRP is clearly a risk marker for cardiovascular disease and is recommended for use in primary prevention. In addition, CRP appears also to contribute to atherogenesis. However, much further research is needed, especially in appropriate animal models, to confirm the possible role of CRP in promoting atherothrombosis.

C-reactive protein stimulates myeloperoxidase release from polymorphonuclear cells and monocytes: implications for acute coronary syndromes

BACKGROUND

C-reactive protein (CRP), the prototypic marker of inflammation, is present in atherosclerotic plaques and appears to promote atherogenesis. Also, CRP has been localized to monocytes and tissue macrophages, which are present in the necrotic core of lesions prone to plaque rupture. Leukocyte-derived myeloperoxidase (MPO), primarily hosted in human polymorphonuclear cells (PMNs), has also been shown to be present in human atherosclerotic lesions. Because MPO and CRP concentrations are increased in acute coronary syndrome (ACS) patients and predict poor outcomes, we tested the effect of CRP on MPO release from PMNs and monocytes.

METHODS

We treated human PMNs and monocytes with CRP (25 and 50 mg/L for 6 h) and measured MPO release as total mass and activity in culture supernatants. We also measured nitro-tyrosinylation (NO(2)-Tyr) of LDL as an indicator of biological activity of CRP-mediated MPO release. Furthermore, we explored the effect of human CRP on MPO release in the rat sterile pouch model.

RESULTS

CRP treatment significantly increased release of MPO (both mass and activity) from human PMNs as well as monocytes (P < 0.05) and caused NO(2)-Tyr of LDL. Human CRP injection in rats resulted in increased concentrations of MPO in pouch exudates (P < 0.05), thus confirming our in vitro data.

CONCLUSIONS

CRP stimulates MPO release both in vitro and in vivo, providing further cogent data for the proinflammatory effect of CRP. These results might further support the role of CRP in ACS.

C-reactive protein predicts ischaemic stroke in haemodialysis patients

Dialysis patients have a higher incidence of cerebrovascular events compared with the general population. However, the value of C-reactive protein (CRP) in predicting stroke in chronic haemodialysis patients is unknown. The aim of this study was to determine the association between serum CRP levels and ischaemic stoke in chronic haemodialysis patients. We retrospectively reviewed 391 chronic haemodialysis patients between November 2001 and November 2004. Patients who developed acute ischaemic stroke within 36-month were recorded. Patients who had lacunar infarction discovered accidentally during brain computed tomography or magnetic resonance imaging scans were recorded for subgroup analysis. The relation of predialysis serum CRP levels, measured via the nephelometric method, to the development of acute ischaemic stroke was analysed using Kaplan-Meier analysis. Factors related to lacunar infarctions were analysed by multivariate logistic regression. Of the 391 patients, 21 developed acute stroke and 24 had lacunar infarction. Kaplan-Meier analysis showed that patients with a serum CRP > 0.8 mg/dl were at risk of developing acute infarction (p = 0.002). In the Cox regression model adjusted for age, cardiovascular disease, hypertension and diabetes, patients with serum CRP > 0.8 mg/dl are at risk of developing acute ischaemic stroke (p = 0.03). In multivariate logistic regression with adjusted for age, hypertension and diabetes, serum CRP levels significantly associated with lacunar infarction (p = 0.05). Serum CRP levels, independent of cardiovascular disease, age, hypertension and diabetes, are associated with the development of acute ischaemic stroke and lacunar infarct in chronic haemodialysis patients.

Value of serial C-reactive protein measurements in non ST-segment elevation acute coronary syndromes

BACKGROUND

Elevated C-reactive protein (CRP) levels at admission are associated with adverse outcomes in patients with non ST-segment elevation acute coronary syndromes (NSTE-ACS).

HYPOTHESIS

C-reactive protein measurement not only at admission, but also after admission, may be useful for predicting adverse outcomes in NSTE-ACS.

METHODS

We measured high-sensitivity CRP levels at admission and at 24 h in 215 patients with NSTE-ACS. An elevated CRP level at admission (admission elevation) was defined as a CRP level of >or=0.300 mg/dL. An increase in the CRP level after admission (increase at 24 h) was considered present when the CRP level at 24 h was higher than the level at admission. Patients were divided into 4 groups according to the presence or absence of admission elevation and increase at 24 h. Coronary angiography was performed at a mean of 3 d after admission.

RESULTS

There were no significant differences among the 4 groups in age, sex, coronary risk factors, or multivessel disease. Patients with both admission elevation and increase at 24 h had higher rates of ST-segment depression and positive troponin T at admission. Multivariate analysis showed that admission elevation (odds ratio [OR] 1.50, p<0.05) and increase at 24 h (OR 6.56, p=0.03) were independent predictors of 30-d events (e.g., death, myocardial infarction, or refractory angina). The highest risk of 30-d events was associated with both admission elevation and increase at 24 h.

CONCLUSIONS

Serial CRP measurements are useful for predicting the risk of subsequent ischemic complications in patients with NSTE-ACS.

Prevalence of risk factors, coronary and systemic atherosclerosis in abdominal aortic aneurysm: comparison with high cardiovascular risk population

Background:

Abdominal aortic aneurysm (AAA) is considered a manifestation of atherosclerosis, however there are epidemiologic, biochemical, and structural differences between occlusive atherosclerosis and AAA. The pathogenesis of AAA involves several factors, first of all destruction of collagen and elastin in the aortic wall. Classical risk factors may influence the evolution and development of AAA, though no consistent association has been found. Aims of the study were to evaluate associations between risk factors and to establish the prevalence of carotid, peripheral vascular and coronary atherosclerosis in patients with AAA.

Methods:

We studied 98 patients with AAA (Group 1) awaiting surgery compared with high cardiovascular risk population having two or more risk factors (n = 82 Group 2). We evaluated traditional risk factors and we studied by eco-doppler and echocardiography the presence of carotid peripheral and coronaric atherosclerosis in two groups.

Results:

We found a higher incidence of AAA in males (p < 0.01). The prevalence of infrarenal AAA was significantly higher than suprarenal AAA (81 vs 17 p < 0.001). No differences in total cholesterol (199 ± 20 vs. 197 ± 25 mg/dl), low-density lipoprotein (142 ± 16 vs. 140 ± 18 mg/dl), triglycerides (138 ± 45 vs. 144 ± 56 mg/dl), glycemia (119 ± 15 vs. 122 ± 20 mg/dl), and fibrinogen (388 ± 154 vs. 362 ± 92 mg/dl) were found between groups. We demonstrated significant differences for cigarette smoking (p < 0.002), systolic and diastolic blood pressure (150 ± 15 vs. 143 ± 14 mmHg and 88 ± 6 vs. 85 ± 7 mmHg, p < 0.0001 and p < 0.05, respectively) and high sensititivity C reactive protein (2.8 ± 1.3 vs. 1.3 ± 0.7 mg/dl, p < 0.001). High-density lipoprotein (HDL) cholesterol levels were significant greater in Group 1 than Group 2 (p < 0.003). Subgroups of patients with AAA and luminal thrombus showed higher fibrinogen levels (564 ± 235 vs. 341 ± 83 mg/dl, p < 0.001) and lower HDL than in controls (46.6 ± 6.5 vs. 52.1 ± 7.8 mg/dl, p < 0.01). We did not find any difference in body mass index, or prevalence of coronary and peripheral atherosclerosis between groups. Conversely, we found higher prevalence of carotid atherosclerosis in Group 2 (9% vs. 25%, p < 0.004).

Conclusion:

Our AAA patients had fewer and different risk factors respect to patients with atherosclerosis. Only elevated blood pressure, C reactive protein, and smoking showed a significant association with AAA. Atherosclerosis in other arterial districts did not differ respect to subjects with high cardiovascular risk. Our results confirm the hypothesis that AAA and atherosclerosis are two different pathological entities with different risk profiles.

C-Reactive Protein: How Has JUPITER Impacted Clinical Practice?

Inflammation plays a pivotal role in all phases of atherosclerosis. High-sensitivity C-reactive protein (hsCRP), the best characterized biomarker of inflammation, is an independent predictor of future cardiovascular (CV) events and can add further insight to risk stratification. Assessment of hsCRP levels in clinical practice is feasible and inexpensive. Justification for the Use of Statins in Primary Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) was a landmark primary prevention trial that enrolled 17,802 apparently healthy men and women with low-density lipoprotein cholesterol levels of less than 130 mg/dL and hsCRP levels of 2 mg/L or higher and randomly assigned them to rosuvastatin, 20 mg daily, or placebo. The trial demonstrated that treatment with statin was associated with significant lowering of hsCRP (37%), with 44% reduction in incident CV and 20% reduction in all-cause mortality. These compelling data from the JUPITER trial should encourage changes in our approach toward primary prevention of CV disease and lipid-lowering therapy, as these data shift the focus toward a link between inflammation, statin therapy, and prevention of atherosclerotic CV diseases.

Expansion of small-diameter abdominal aortic aneurysms is not reflected by the release of inflammatory mediators IL-6, MMP-9 and CRP in plasma

OBJECTIVES

The aim of this study was to evaluate a possible correlation between plasma levels of interleukin-6 (IL-6), metalloproteinase-9 (MMP-9) and C-reactive protein (CRP) and the expansion of small abdominal aortic aneurysms (AAAs).

DESIGN

Patients were selected from a prospective randomised clinical trial and categorised in two groups, in which one group received active treatment (azithromycin) and the other received placebo. No statistical difference in the expansion rate of AAAs between the groups was found and the two groups were considered as one cohort in the present study.

MATERIAL AND METHODS

In this study, 213 patients with AAAs between 35 and 49 mm were followed-up with ultrasound examination every 6th month. Blood samples were taken on two occasions (6 months apart). IL-6 and MMP-9 were analysed on one occasion using Quantikine analysing kits (R&D Systems, Inc., USA). CRP was analysed using sensitive-CRP method.

RESULTS

Levels of IL-6, MMP-9 and CRP did not correlate with AAA expansion. Neither was there any correlation between statin medication and changes in MMP-9 levels over the 6-month period. Patients on statins had a lower expansion rate than those not taking statins: 0.16 versus 0.25 cm per year.

CONCLUSION

No correlation was found between levels of circulating IL-6, MMP-9, CRP and the expansion of small-diameter AAAs, indicating no clinical use of these markers in AAA surveillance.

Derivatives of reactive oxygen metabolites correlates with high-sensitivity C-reactive protein

AIM

High-sensitivity C-reactive protein (hsCRP) is a predictor of cardiovascular events. Although oxidative stress may also be related to cardiovascular disease, there are few studies comparing the two. We therefore examined the association of hsCRP, serum lipids, and derivatives of reactive oxygen metabolites (D-ROMs) in coronary artery disease.

METHODS

We measured the levels of serum lipids, hsCRP, plasma brain natriuretic peptides (BNP) and D-ROMs in 131 consecutive patients undergoing cardiac catheterization. We divided these subjects into three groups according to their levels of hsCRP.

RESULTS

In group C (hsCRP>3.0 mg/L), mean levels of serum D-ROMs were significantly higher than in groups A (hsCRP<1.0 mg/L) and B (hsCRP 1.0 to 3.0 mg/L). Serum levels of D-ROMs and log (hsCRP) correlated in the total population (r=0.479, p<0.0001), and D-ROMs, HDL-C, LDL-C and log-transformed plasma BNP were independent predictors of hsCRP (p<0.0001).

CONCLUSION

We concluded that oxidative stress increases in patients at high risk for cardiovascular events based on their hsCRP.

C-reactive protein in acute coronary syndromes: A perfect trigger or an excellent indicator?

Recent researches have shown that active inflammation is considered a crucial step in the pathogenesis of acute coronary syndromes. C-reactive protein has long been utilized as a nonspecific clinical marker of inflammation, with the advent of high-sensitivity assays, has emerged as one of the most powerful independent predictors of cardiovascular disease. However, it is not clear whether C-reactive protein is only an excellent indicator or a perfect trigger in acute coronary syndromes. In this paper, we discussed the role of C-reactive protein in the pathogenesis of acute coronary syndromes.

Present and Future Biochemical Markers for Detection of Acute Coronary Syndrome

The use of biochemical markers in the diagnosis and management of patients with acute coronary syndrome has increased continually in recent decades. The development of highly sensitive and cardiac-specific troponin assays has changed the view on diagnosis of myocardial infarction and also extended the role of biochemical markers of necrosis into risk stratification and guidance for treatment. The consensus definition of myocardial infarction places increased emphasis on cardiac marker testing, with cardiac troponin replacing creatine kinase MB as the "gold standard" for diagnosis of myocardial infarction. Along with advances in the use of more cardiac-specific markers of myocardial necrosis, biochemical markers that are involved in the progression of atherosclerotic plaques to the vulnerable state or that signal the presence of vulnerable plaques have recently been identified. These markers have variable abilities to predict the risk of an individual for acute coronary syndrome. The aim of this review is to provide an overview of the well-established markers of myocardial necrosis, with a special focus on cardiac troponin I, together with a summary of some of the potential future markers of inflammation, plaque instability, and ischemia.

C-reactive protein and coronary heart disease: a critical review

Modestly elevated baseline concentrations of C-reactive protein (CRP), the classical acute phase protein, are associated with the long-term risk of coronary heart disease in general populations, whilst the major acute phase response of CRP following myocardial infarction is associated with death and cardiac complications. The pathogenic and clinical significance of these associations is controversial. Here we critically review the evidence and describe large-scale epidemiological studies, novel experiments and possible specific therapies which will rigorously inform the debate. We distinguish between the potential pathogenicity of high acute phase circulating CRP concentrations in individuals with substantial tissue damage and modest but persistent increases in baseline values in generally healthy subjects.

Inflammatory gene polymorphisms and susceptibility to kawasaki disease and its arterial sequelae

OBJECTIVE

We tested the hypothesis that single-nucleotide polymorphisms of inflammatory genes C-reactive protein (CRP) and tumor necrosis factor alpha (TNF-alpha) may exert influence on susceptibility to Kawasaki disease and its arterial sequelae.

METHODS

We analyzed the CRP +1444 C-->T and TNF-alpha -308 G-->A polymorphisms in 167 patients aged 8.9 +/- 4.1 years with a history of Kawasaki disease (73 with and 94 without coronary aneurysms) and 124 healthy control subjects. For patients with Kawasaki disease, we further determined whether these single-nucleotide polymorphisms were associated with coronary aneurysms, carotid arterial stiffening, and intima-media thickness.

RESULTS

Genotypic and allelic frequencies of CRP +1444 for T carrier and TNF-alpha -308 for A carrier were significantly higher in patients than in control subjects. The genotypic and allelic distributions did not differ between patients with and those without coronary aneurysms; however, patients with CRP +1444 CT/TT genotype compared with those with a CC genotype and patients with TNF-alpha -308 GA/AA genotype compared with those with a GG genotype had significantly greater carotid arterial stiffness and intima-media thickness. Carriers of both CRP +1444 T allele and TNF-alpha -308 A allele had the highest susceptibility to Kawasaki disease and a significant trend of increased arterial stiffness and intima-media thickness compared with those who carried either 1 or none of the rare alleles. Multiple linear regression analysis identified CRP +1444 allele carrier as a significant determinant of both carotid stiffness and carotid intima-media thickness and TNF-alpha -308 A allele carrier as a determinant of only intima-media thickness.

CONCLUSIONS

Our findings suggest that CRP +1444 C-->T and TNF-alpha -308 G-->A polymorphisms are associated with predisposition to Kawasaki disease and, in patients with Kawasaki disease, increased carotid arterial stiffness and intima-media thickness in the long-term.

C-reactive protein and vein graft disease: evidence for a direct effect on smooth muscle cell phenotype via modulation of PDGF receptor-beta

Plasma C-reactive protein (CRP) concentration is a biomarker of systemic atherosclerosis and may also be associated with vein graft disease. It remains unclear whether CRP is also an important modulator of biological events in the vessel wall. We hypothesized that CRP influences vein graft healing by stimulating smooth muscle cells (SMCs) to undergo a phenotypic switch. Distribution of CRP was examined by immunohistochemistry in prebypass human saphenous veins (HSVs, n = 21) and failing vein grafts (n = 18, 25-4,400 days postoperatively). Quiescent HSV SMCs were stimulated with human CRP (5-50 microg/ml). SMC migration was assessed in modified Boyden chambers with platelet-derived growth factor (PDGF)-BB (5-10 ng/ml) as the chemoattractant. SMC viability and proliferation were assessed by trypan blue exclusion and reduction of Alamar Blue substrate, respectively. Expression of PDGF ligand and receptor (PDGFR) genes was examined at RNA and protein levels after 24-72 h of CRP exposure. CRP staining was present in 13 of 18 diseased vein grafts, where it localized to the deep media and adventitia, but it was minimally detectable in most prebypass veins. SMCs pretreated with CRP demonstrated a dose-dependent increase in migration to PDGF-BB (P = 0.02), which was inhibited by a PDGF-neutralizing antibody. SMCs treated with CRP showed a dose-dependent increase in PDGFRbeta expression and phosphorylation after 24-48 h. Exogenous CRP had no effect on SMC viability or proliferation. These data suggest that CRP is detectable within the wall of most diseased vein grafts, where it may exert local effects. Clinically relevant levels of CRP can stimulate SMC migration by a mechanism that may involve upregulation and activation of PDGFRbeta.

Regular exercise training compared with percutaneous intervention leads to a reduction of inflammatory markers and cardiovascular events in patients with coronary artery disease

BACKGROUND

Chronic vascular inflammation may trigger ischemic events whereas regular physical exercise training (ET) has shown to be cardioprotective in patients with coronary artery disease (CAD). We investigated the impact of 2 years regular ET versus percutaneous intervention (PCI) on chronic inflammation and cardiovascular events.

METHODS AND RESULTS

A total of 101 male patients with stable CAD and an indication for revascularization were prospectively randomized to regular ET (n=51) or PCI with stentimplantation (n=50). High-sensitive C-reactive protein and interleukin-6, exercise capacity and ischemic endpoints were analyzed at baseline and after 2 years. At 2 years maximal oxygen consumption (VO2 max) increased by 10% in the ET group (23.3+/-0.6 to 25.7+/-1.0 ml O2/kg/min; P=0.0171 versus baseline) versus 7% in the PCI group (22.3+/-0.8 to 23.9+/-1.2 ml O2/kg/min; P=0.4248). In a subgroup of patients, high-sensitive C-reactive protein levels and interleukin-6 levels were significantly reduced after ET by 41 and 18%, respectively, whereas no relevant changes were observed in the PCI group. Event-free survival rates after 24 months were 78% (ET) versus 62% (PCI) (P=0.039).

CONCLUSION

In patients with stable coronary artery disease, regular physical exercise is associated with a reduction of inflammatory markers and ischemic events.

Local and Systemic Mechanisms of Plaque Rupture

Mechanisms at the basis of coronary plaque instability are still elusive. On the one hand, accumulating data, from clinical and postmortem studies, suggest the role of systemic factors, in particular inflammation, in plaque rupture. On the other hand, local factors, in particular plaque composition, such as a large lipid-rich core and a thin fibrous cap, presence of activated inflammatory cells, presence of plaque neovascularization, and specific apoptotic processes, may contribute to plaque susceptibility to rupture. In addition, other cofactors, such as platelet activation and clotting factors, are involved in the transition from stable to unstable plaque. The authors discuss the possibility that all these factors have a role in the development of acute coronary syndrome: a systemic inflammatory condition with an enhanced coagulation state may activate local hemodynamic, mechanical, and immune reactions leading to intraplaque cells activation, fibrous cap lysis, and thrombus formation.