C-reactive protein (+1444C>T) polymorphism influences CRP response following a moderate inflammatory stimulus

Quantile-dependent expressivity of serum C-reactive protein concentrations in family sets

Background

“Quantile-dependent expressivity” occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g., C-reactive protein, CRP) is high or low relative to its distribution. We have previously shown that the heritabilities (h²) of coffee and alcohol consumption, postprandial lipemia, lipoproteins, leptin, adiponectin, adiposity, and pulmonary function are quantile-specific. Whether CRP heritability is quantile-specific is currently unknown.

Methods

Serum CRP concentrations from 2,036 sibships and 6,144 offspring-parent pairs were analyzed from the Framingham Heart Study. Quantile-specific heritability from full-sib (β_FS, h² ={(1 + 8r_spouseβ_FS)^0.5 − 1}/(2r_spouse)) and offspring-parent regression slopes (β_OP, h² = 2β_OP/(1 + r_spouse)) were estimated robustly by quantile regression with nonparametric significance determined from 1,000 bootstrap samples.

Results

Quantile-specific h² (±SE) increased with increasing percentiles of the offspring’s age- and sex-adjusted CRP distribution when estimated from β_OP (P_trend = 0.0004): 0.02 ± 0.01 at the 10th, 0.04 ± 0.01 at the 25th, 0.10 ± 0.02 at the 50th, 0.20 ± 0.05 at the 75th, and 0.33 ± 0.10 at the 90th percentile, and when estimated from β_FS (P_trend = 0.0008): 0.03±0.01 at the 10th, 0.06 ± 0.02 at the 25th, 0.14 ± 0.03 at the 50th, 0.24 ± 0.05 at the 75th, and 0.53 ± 0.21 at the 90th percentile.

Conclusion

Heritability of serum CRP concentration is quantile-specific, which may explain or contribute to the inflated CRP differences between CRP (rs1130864, rs1205, rs1800947, rs2794521, rs3091244), FGB (rs1800787), IL-6 (rs1800795, rs1800796), IL6R (rs8192284), TNF-α (rs1800629) and APOE genotypes following CABG surgery, stroke, TIA, curative esophagectomy, intensive periodontal therapy, or acute exercise; during acute coronary syndrome or Staphylococcus aureus bacteremia; or in patients with chronic rheumatoid arthritis, diabetes, peripheral arterial disease, ankylosing spondylitis, obesity or inflammatory bowel disease or who smoke.

Increased Baseline C-Reactive Protein Concentrations Are Associated with Increased Risk of Infections: Results from 2 Large Danish Population Cohorts

BACKGROUND

The acute-phase reactant C-reactive protein (CRP) increases rapidly during an infection. We tested the hypothesis that chronic low-level increases in CRP are associated with an increased risk of infectious disease.

METHODS

We studied 9660 individuals from a prospective general population cohort, including 3592 in whom infectious disease developed, and another 60 896 individuals from a cross-sectional general population study, of whom 13 332 developed infectious disease; 55% were women, and the mean age was 57 years. Hospital diagnoses of infections in 1977-2010 were based on International Classification of Diseases-coded discharge records from the national Danish Patient Registry. We measured CRP concentrations and conducted genotyping for 4 CRP polymorphisms that increase CRP. Individuals with CRP >10 mg/L were excluded because of possible ongoing infection at the time of testing.

RESULTS

Individuals with CRP >3 mg/L had 1.2 and 1.7 times increased risk of infectious disease, in the prospective general population cohort and the cross-sectional general population study, respectively, compared with individuals with CRP <1 mg/L. In the combined populations, individuals in the highest CRP tertile (compared with the lowest) had an increased risk of bacterial diseases (hazard ratio 1.7, 95% CI 1.6-1.8), but not viral, mycosis, and parasitic diseases. The increased risk was mainly carried by pneumonia, sepsis, and particularly gram-negative infections. None of the genotype combinations examined conferred an increased risk of infectious disease.

CONCLUSIONS

Chronic low-level CRP increases were associated with increased risk of bacterial infections, gram-negative infections in particular. Genotypes associated with increases in CRP were not associated with increased risk of infection.

Fibrinogen Degradation Products and Periodontitis: Deciphering the Connection

INTRODUCTION

Fibrinogen degradation products (e.g. D-dimer) arise from digested fibrin clots and fibrinogen. Elevated concentrations accompany activation of coagulation and fibrinolysis and indicate chronic inflammatory diseases. D-Dimer tests are a quick, noninvasive method to rule out abnormal clotting. Periodontitis strongly affects the haemostatic system and evokes a procoagulant state. Correlation of chronic periodontitis with early indicators of disease (biomarkers) might be useful.

AIM

The aim of the study was to examine whether the plasma D-dimer concentration reflects the progression of chronic periodontitis and the beneficial effect of periodontal therapy.

MATERIALS AND METHODS

Forty randomly selected subjects were divided into four groups, Group I: 10 healthy subjects, Group II: 10 with mild periodontitis, Group III: 10 with moderate periodontitis, Group IV: 10 with severe periodontitis. After thorough dental and periodontal examination, 3 mL of venous blood was collected for measurement of fibrinogen degradation products.

RESULTS

The patients with moderate and chronic periodontitis exhibited high concentrations of D-dimer (mean value 434.98-535.52 mcg/mL), whereas subjects with mild or no periodontitis exhibited values of 329.78-211.29 mcg/mL. Concentrations of D-dimer were significantly reduced after therapy of all classes of periodontitis.

CONCLUSION

Periodontal treatment can reduce amount of D-dimer in the plasma. A higher than normal concentration is observed in chronic periodontitis.

CRP genotype and haplotype associations with serum C-reactive protein level and DAS28 in untreated early rheumatoid arthritis patients

INTRODUCTION

Single-nucleotide polymorphisms (SNPs) in the CRP gene are implicated in the regulation of the constitutional C-reactive protein (CRP) expression and its response to proinflammatory stimuli. Previous reports suggest that these effects may have an impact on clinical decision-making tools based on CRP, such as the Disease Activity Score in 28 joints (DAS28). We aimed to investigate the possible association between seven CRP SNPs, their haplotypes and the serum levels of CRP, as well as DAS28 scores, in two cohorts of untreated active early rheumatoid arthritis (RA) patients followed during their initial treatment.

METHODS

Overall, 315 patients with RA from two randomized controlled trials (the CIMESTRA and OPERA trials) who were naïve to disease-modifying antirheumatic drugs and steroids with disease durations less than 6 months were included. Seven CRP SNPs were investigated: rs11265257, rs1130864, rs1205, rs1800947, rs2808632, rs3093077 and rs876538. The genotype and haplotype associations with CRP and DAS28 levels were evaluated using linear regression analysis adjusted for age, sex and treatment.

RESULTS

The minor allele of rs1205 C > T was associated with decreased CRP levels at baseline (P = 0.03), with the TT genotype having a 50% reduction in CRP from 16.7 to 8.4 mg/L (P = 0.005) compared to homozygosity of the major allele, but no association was observed at year 1 (P = 0.38). The common H2 haplotype, characterized by the T allele of rs1205, was associated with a 26% reduction in CRP at baseline (P = 0.043), although no effect was observed at year 1 (P = 0.466). No other SNP or haplotype was associated with CRP at baseline or at year 1 (P ≥ 0.09). We observed no associations between SNPs or haplotypes and DAS28 scores at baseline or at year 1 (P ≥ 0.10).

CONCLUSION

CRP genotype and haplotype were only marginally associated with serum CRP levels and had no association with the DAS28 score. This study shows that DAS28, the core parameter for inflammatory activity in RA, can be used for clinical decision-making without adjustment for CRP gene variants.

TRIAL REGISTRATION

The OPERA study is registered at Clinicaltrials.gov (NCT00660647). The CIMESTRA study is not listed in a clinical trials registry, because patients were included between October 1999 and October 2002.

Genetic variants in C-reactive protein and ischemic stroke susceptibility

Considerable discrepancies in the previously reported associations of the C-reactive protein (CRP) gene variants and ischemic stroke (IS) risk prompted us to perform this meta-analysis. We selected the fixed effects Mantel-Haenszel method to estimate the risk of IS [OR (odds ratio) along with its 95 % CI (confidence interval)] in relation to the CRP variants (-717 A > G, 1444 C > T). Heterogeneity test, influence analysis and publication bias test were appropriately performed using respective methods. We analyzed 1,926 IS patients and 2,678 controls and found the -717 A > G variant was not significantly associated with overall IS risk. Subsequent analysis of the 1444 C > T variant involving 3,278 samples similarly revealed no significant association with IS. There was no substantial heterogeneity or publication bias in this analysis. Our meta-analysis may provide first evidence showing that genetic variants within the CRP locus are unlikely to modulate risk of IS.

A novel haplotype within C-reactive protein gene influences CRP levels and coronary heart disease risk in Northwest Indians

According to several epidemiological and clinical studies, the concentration of C-reactive protein (CRP) in blood is associated with the risk of coronary heart disease (CHD). However, these studies are limited in high incidence and prevalence area of North-West India. The present case control study investigated the contribution of three relevant CRP single nucleotide polymorphisms: -717A>G located in the promoter region (rs2794521), +1059G>C on exon2 (rs1800947) and +1444C>T in the 3' UTR (rs1130864) in 180 angiographically verified CHD cases and 175 control subjects. Minor allele frequencies (G, C and T) of rs2794521, rs1800947 and rs1130864 are observed to be 21.1, 11.7, 29.4 and 11.4, 10.0, 19.7 % in CHD cases and controls respectively. AA genotype of -717A>G and TT genotype of +1444C>T were significantly associated (P = 0.02 & 0.03 respectively) with the risk of CHD whereas, +1059G and +1444T were found to be strongly related (P = 0.023 & P = 0.008 respectively) with multivariable adjusted CRP levels. AGT Haplotype was significantly associated with the adjusted CRP levels (P < 0.05). Disease association analysis revealed that haplotype AGT influences CHD risk (OR 2.4, 95 % CI 1.23-4.84, P = 0.006) which exacerbates after correcting the confounding effects of risk variables (OR 2.5, 95 % CI 1.27-4.99, P = 0.004). With the global index of Akaike information criterion, it has been observed that the carrying each single unit of this susceptibility haplotype increases CHD risk by a value of 2.41 ± 0.439 (β ± SE) in the recessive mode.

Pro-inflammatory interleukin-1 genotypes potentiate the risk of coronary artery disease and cardiovascular events mediated by oxidized phospholipids and lipoprotein(a)

OBJECTIVES

The aim of this study was to assess the influence of pro-inflammatory interleukin (IL)-1 genotype status on the risk for coronary artery disease (CAD), defined as >50% diameter stenosis, and cardiovascular events mediated by oxidized phospholipids (OxPLs) and lipoprotein (Lp) (a).

BACKGROUND

OxPLs are pro-inflammatory, circulate on Lp(a), and mediate CAD. Genetic variations in the IL-1 region are associated with increased inflammatory mediators.

METHODS

IL-1 genotypes, OxPL on apolipoprotein B-100 (OxPL/apoB), and Lp(a) levels were measured in 499 patients undergoing coronary angiography. The composite genotype termed IL-1(+) was defined by 3 single-nucleotide polymorphisms in the IL-1 gene cluster associated with higher levels of pro-inflammatory cytokines. All other IL-1 genotypes were termed IL-1(-).

RESULTS

Among IL-1(+) patients, the highest quartile of OxPL/apoB was significantly associated with a higher risk for CAD compared with the lowest quartile (odds ratio [OR]: 2.84; p = 0.001). This effect was accentuated in patients age ≤60 years (OR: 7.03; p < 0.001). In IL-1(-) patients, OxPL/apoB levels showed no association with CAD. The interaction was significant for OxPL/apoB (OR: 1.99; p = 0.004) and Lp(a) (OR: 1.96; p < 0.001) in the IL-1(+) group versus the IL-1(-) group in patients age ≤60 years but not in those age >60 years. In IL-1(+) patients age ≤60 years, after adjustment for established risk factors, high-sensitivity C-reactive protein, and Lp(a), OxPL/apoB remained an independent predictor of CAD. IL-1(+) patients above the median OxPL/apoB presented to the cardiac catheterization laboratory a mean of 3.9 years earlier (p = 0.002) and had worse 4-year event-free survival (death, myocardial infarction, stroke, and need for revascularization) compared with other groups (p = 0.006).

CONCLUSIONS

Our study suggests that IL-1 genotype status can stratify population risk for CAD and cardiovascular events mediated by OxPL. These data suggest a clinically relevant biological link between pro-inflammatory IL-1 genotype, oxidation of phospholipids, Lp(a), and genetic predisposition to CAD and cardiovascular events.

Correlation of C-reactive protein haplotypes with serum C-reactive protein level and response to anti-tumor necrosis factor therapy in UK rheumatoid arthritis patients: results from the Biologics in Rheumatoid Arthritis Genetics and Genomics Study Syndicate cohort

INTRODUCTION

In many European countries, restrictions exist around the prescription of anti-tumor necrosis factor (anti-TNF) treatments for rheumatoid arthritis (RA). Eligibility and response to treatment is assessed by using the disease activity score 28 (DAS28) algorithm, which incorporates one of two inflammatory markers, erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP). Although DAS28-CRP provides a more reliable measure of disease activity, functional variants exist within the CRP gene that affect basal CRP production.

METHODS

DNA samples from the Biologics in Rheumatoid Arthritis Genetics and Genomics Study Syndicate (BRAGGSS) were genotyped for rs1205, rs1800947, and rs3091244 by using either TaqMan or the Sequenom MassARRAY iPLEX system.

RESULTS

Baseline CRP measurements were available for 599 samples with 442 also having data 6 months after treatment with an anti-TNF. For these 442 samples, the study had > 80% power to detect a clinically meaningful difference of 0.6 DAS28 Units for an allele frequency of 5%. Estimated haplotype frequencies corresponded with previous frequencies reported in the literature. Overall, no significant association was observed between any of the markers investigated and baseline CRP levels. Further, CRP haplotypes did not correlate with baseline CRP (P = 0.593), baseline DAS28-CRP (P = 0.540), or change in DAS28-CRP after treatment with an anti-TNF over a 6-month period (P = 0.302).

CONCLUSIONS

Although CRP genotype may influence baseline CRP levels, in patients with very active disease, no such association was found. This suggests that genetic variation at the CRP locus does not influence DAS28-CRP, which may continue to be used in determining eligibility for and response to anti-TNF treatment, without adjusting for CRP genotype.

CRP and CD14 polymorphisms correlate with coronary plaque volume in patients with coronary artery disease--IVUS substudy of the ENCORE trials

BACKGROUND

Several proinflammatory single-nucleotide polymorphisms (SNPs) have been linked to the progression of atherosclerosis and coronary artery disease (CAD). Plaque size and its destabilization by inflammatory processes are major determinants of ischemia and acute coronary syndromes. Intravascular ultrasound (IVUS) allows for quantification of plaque size in vivo. We therefore investigated the relation of plaque size with mutations of proinflammatory genes in patients with CAD.

METHODS

In 196 patients with stable CAD enrolled in the ENCORE trials coronary plaque and vessel volume was assessed by IVUS. 173 patients were successfully genotyped for polymorphisms of proinflammatory genes CD14 C(-260)T and CRP C(+1444)T using the single-nucleotide polymorphism polymerase chain reaction (SNP PCR) approach.

RESULTS

Baseline characteristics were comparable for all genotype groups. Higher ratios of plaque volume/vessel volume were observed in patients with the CRP 1444TT (n=11) and CD14 260TT (n=33) genotypes (p=0.016 and p=0.026, respectively).

CONCLUSION

In patients with stable coronary artery disease the CRP 1444TT and CD14 260TT variants are associated with larger coronary plaque volume independently of concomitant cardiovascular risk factors.

Study of C-reactive protein and myocardial infarction in the Indian population

To analyse the association of high sensitivity C-reactive (hsCRP) protein levels and -717A/G single nucleotide polymorphism of CRP with acute myocardial infarction (AMI) in the Indian population. Study population included 100 MI cases wherein 32 patients had experienced previous MI (MI-Group-1), 68 MI cases were recruited at presentation (MI-Group-2) and equal number of age and gender matched healthy individuals. hsCRP levels were determined by ELISA and genotyping of -717A/G was carried out by polymerase chain reaction-based restriction digestion method. The -717A/G genotypes did not influence hsCRP level and their distribution did not differ between groups. However, in the present study hsCRP demonstrated significant correlation with BMI in controls of both the genders and with triglycerides in females of AMI at presentation who otherwise are with low risk profile. Identifying traditional risk factors associated with inflammation may help in controlling the acute event.

Mechanisms involved in the association between periodontal diseases and cardiovascular disease

It is now well accepted that besides the cholesterol associated mechanisms of atherogenesis, inflammation plays a crucial role in all stages of the development of the atherosclerotic lesion. This 'inflammation hypothesis' raises the possibility that through systemic elevations of pro-inflammatory cytokines, periodontal diseases might also contribute to systemic inflammation and, therefore, to atherogenesis. In fact, there is evidence that periodontal diseases are associated with higher systemic levels of high-sensitivity C-reactive protein and a low grade systemic inflammation. This phenomenon has been explained based on mechanisms associated with either the infectious or the inflammatory nature of periodontal diseases. The purposes of this article were to review (1) the evidence suggesting a role for oral bacterial species, particularly periodontal pathogens, in atherogenesis; (2) the potential mechanisms explaining an etiological role for oral bacteria in atherosclerosis; (3) the evidence suggesting that periodontal infections are accompanied by a heightened state of systemic inflammation; (4) the potential sources of systemic inflammatory biomarkers associated with periodontal diseases; and (5) the effects of periodontal therapy on systemic inflammatory biomarkers and cardiovascular risk.

Novel Endothelial Biomarkers: Implications for Periodontal Disease and CVD

Endothelial cells are actively involved in various aspects of vascular biology and different stages of atherosclerosis. Endothelial function is increasingly used as an important outcome measure in cardiovascular research. Endothelial progenitor cells (EPCs) are closely linked to endothelial function, and their biomarkers have received much attention. EPCs may not only serve as a pool of progenitor cells and possess the capacity to repair the damaged vasculature, but also act as potent effectors in systemic inflammation, suggesting that EPCs may play a critical role in maintaining endothelial function and the progression of cardiovascular disease (CVD). Emerging evidence shows an association of periodontal infections (gingivitis and periodontitis) with endothelial dysfunction, while the relevant mechanisms remain unknown. Our recent finding of the association of periodontitis with EPCs warrants their utilization as additional biomarkers in future studies on periodontal medicine. This review starts with a brief account on the current understanding of the nature of periodontal infections and their link with systemic inflammation and endothelial dysfunction. The paper also provides an update on endothelial biology and function as well as the novel biomarkers of EPCs and concludes with clinical studies on periodontal diseases and CVD.

Comparison Between Serum hsCRP and LDL Cholesterol for Search of a Better Predictor for Ischemic Heart Disease

Acute myocardial Infarction is one of the major causes of morbidity & mortality in world and atherosclerosis is the major cause of ischemic heart disease. In order to determine the better clinical marker of atherosclerosis, we estimated serum low-density lipoprotein (LDL-C) and high sensitivity C-reactive protein (hsCRP). Hundred patients of myocardial infarction and 100 controls irrespective of age and sex were studied for these parameters over a period of 2 years. The statistical analysis showed that the serum hsCRP was significantly raised in myocardial infarction cases than controls (P < 0.01) but LDL-C was not (P > 0.05). We conclude that the serum hsCRP has better predictive value for risk of atherosclerosis.

Effect of periodontal treatment on circulating CD34(+) cells and peripheral vascular endothelial function: a randomized controlled trial

AIM

periodontal disease is associated with endothelial dysfunction and increased circulating progenitor cell (CPC) count. This study sought to investigate the effect of periodontal treatment on CPC count and vascular endothelial function.

MATERIALS AND METHODS

a single-blind, randomized controlled trial was conducted in 50 otherwise healthy subjects with moderate-to-severe chronic periodontitis. They were randomly assigned into Treatment group (n=25), in whom periodontal treatment was conducted immediately, and Control group (n=25), in whom periodontal treatment was postponed until the completion of this 3-month study. CPCs and peripheral endothelial function were evaluated at baseline and 3-month follow-up using flow cytometry and peripheral arterial tonometry, respectively.

RESULTS

based on the intention-to-treat analysis, periodontal treatment exhibited neutral effects on endothelial function [treatment effect: 0.03, 95% confidence interval (CI): -0.29 to 0.35, p=0.85]. However, circulating CD34(+) cells count significantly decreased in the Treatment group compared with the controls (treatment effect: -29.85 cells/μl, 95% CI: -52.62 to -7.08, p=0.011). The reduction of circulating CD34(+) count was positively correlated with the decrease in sites% with bleeding on probing or periodontal pockets 4 mm.

CONCLUSIONS

this study suggests that treatment of periodontitis has neutral effects on peripheral endothelial function but significantly decreases circulating CD34(+) cell count.

Combined effect of C-reactive protein gene SNP +2147 A/G and interleukin-6 receptor gene SNP rs2229238 C/T on anthropometric characteristics among school children in Taiwan

OBJECTIVE

The purpose of this study was to explore the combined effect of the C-reactive protein (CRP) +2147 A/G (rs1205) and interleukin (IL)-6R rs2229238 C/T single-nucleotide polymorphisms (SNPs) on the anthropometric variables of school children in Taiwan.

SUBJECTS AND DESIGN

Cross-sectional analyses were performed using the data from the Taipei Children Heart Study-II. After multi-stage sampling, we selected 430 boys and 463 girls with an average age of 13.1 years. We genotyped these individuals for the CRP +2147 A/G and IL-6R rs2229238 C/T SNPs using a TaqMan 5' nuclease assay. Anthropometric characteristics, which included body height, body weight (BW), body mass index (BMI), waist circumference (WC), hip circumference (HC), body fat percentage (BF), and waist circumference to height ratio (WHtR), were measured/calculated.

RESULTS

When considering the CRP +2147 A/G polymorphism, GG genotype boys were heavier and had larger BMI, WC, HC, BF and WHtR than A allele carriers. The odds ratio (OR) of larger WHtR in GG genotype boys was 2.14 (95% CI: 1.09-4.21). For the IL-6R rs2229238 C/T polymorphism, T allele carrier girls had larger WC and WHtR than those carrying the CC genotype. The OR of a larger HC for T allele carrier boys was 2.33 (95% CI: 1.16-4.68). Boys with the GG genotype of CRP +2147 A/G and the CC genotype of IL-6R rs2229238 C/T had higher OR for BW, BMI, WC, HC, BF and WHtR than boys who were carriers of the A allele of CRP +2147 A/G and had the CC genotype of IL-6R rs2229238 C/T (OR range=3.86-8.04, all P<0.05).

CONCLUSION

Boys who carry the GG genotype of CRP +2147 A/G and the CC genotype of IL-6R rs2229238 C/T have a greater risk of having abnormal BW, BMI, WC, HC, BF and WHtR and of developing obesity than individuals who do not have these genotypes.

A genetic association study of serum acute-phase C-reactive protein levels in rheumatoid arthritis: implications for clinical interpretation

BACKGROUND

The acute-phase increase in serum C-reactive protein (CRP) is used to diagnose and monitor infectious and inflammatory diseases. Little is known about the influence of genetics on acute-phase CRP, particularly in patients with chronic inflammation.

METHODS AND FINDINGS

We studied two independent sets of patients with chronic inflammation due to rheumatoid arthritis (total 695 patients). A tagSNP approach captured common variation at the CRP locus and the relationship between genotype and serum CRP was explored by linear modelling. Erythrocyte sedimentation rate (ESR) was incorporated as an independent marker of inflammation to adjust for the varying levels of inflammatory disease activity between patients. Common genetic variants at the CRP locus were associated with acute-phase serum CRP (for the most associated haplotype: p = 0.002, p<0.0005, p<0.0005 in patient sets 1, 2, and the combined sets, respectively), translating into an approximately 3.5-fold change in expected serum CRP concentrations between carriers of two common CRP haplotypes. For example, when ESR = 50 mm/h the expected geometric mean CRP (95% confidence interval) concentration was 43.1 mg/l (32.1-50.0) for haplotype 1 and 14.2 mg/l (9.5-23.2) for haplotype 4.

CONCLUSIONS

Our findings raise questions about the interpretation of acute-phase serum CRP. In particular, failure to take into account the potential for genetic effects may result in the inappropriate reassurance or suboptimal treatment of patients simply because they carry low-CRP-associated genetic variants. CRP is increasingly being incorporated into clinical algorithms to compare disease activity between patients and to predict future clinical events: our findings impact on the use of these algorithms. For example, where access to effective, but expensive, biological therapies in rheumatoid arthritis is rationed on the basis of a DAS28-CRP clinical activity score, then two patients with identical underlying disease severity could be given, or denied, treatment on the basis of CRP genotype alone. The accuracy and utility of these algorithms might be improved by using a genetically adjusted CRP measurement.

Human gingiva is another site of C-reactive protein formation

OBJECTIVES

C-reactive protein (CRP) is primarily synthesized in the liver. It is hypothesized that human gingiva per se may produce CRP and its expression could be associated with IL-6. This study elucidated the CRP expression profile in human gingiva and its possible association with IL-6.

MATERIALS AND METHODS

Ninety-four gingival biopsies were collected from 44 subjects with chronic periodontitis and 18 periodontally healthy subjects. CRP protein was detected by immunohistochemistry and Western blotting, while CRP and IL-6 mRNAs were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR. CRP protein expression in the reconstituted human gingival epithelia (RHGE) was examined by the particle-enhanced immunoturbidimetric assay and Western blotting.

RESULTS

CRP protein was detected in gingival tissues from patients and healthy subjects by immunohistochemistry and confirmed by Western blotting. Its expression pattern and level at 16 pairs of periodontal pocket tissues and the adjacent clinically healthy tissues from 16 patients were significantly interrelated (r(s)=0.693, p<0.01). CRP mRNA expression was strongly correlated with IL-6 (r=0.694, p<0.001). Both CRP protein and mRNA were detected in the RHGE.

CONCLUSIONS

The present study shows for the first time that human gingiva is able to produce CRP in situ that may be associated with IL-6 activity.

Association of MCP-1 -2518 A/G single nucleotide polymorphism with the serum level of CRP in Slovak patients with ischemic heart disease, angina pectoris, and hypertension

The aim of our work was to find if MCP-1 -2518 (A/G) single nucleotide polymorphism (SNP) influences somehow the serum concentrations of high-sensitive CRP (hsCRP) both in patients suffering from ischemic heart disease (IHD), myocardial infarction (MI), angina pectoris (AP), and hypertension (HT) and in control group of healthy subjects. Totally, 263 patients with the diagnosis of IHD, out of them 89 with MI, 145 with AP, 205 with HT, and also 67 healthy subjects were included in the study. First, we estimated the serum levels of hsCRP. We found that patients with AP had significantly higher serum level of hsCRP than both control group of healthy subjects (P = .043) and IHD patients without AP (P = .026). The presence of the mutant G allele statistically significantly correlated with the higher serum levels of hsCRP in patients with IHD (P = .016), AP (P = .004), and HT (P = .013). Higher correlations were found in men (AP: P = .019; HT: P = .047). In all cases the highest levels of hsCRP were found both in patients and healthy controls with homozygous GG genotype.

Periodontitis-associated up-regulation of systemic inflammatory mediator level may increase the risk of coronary heart disease

BACKGROUND AND OBJECTIVE

Although an elevation in the concentration of high-sensitivity C-reactive protein (hs-CRP) as a result of periodontal infection may account for an increased risk of developing coronary heart disease (CHD), the effect of periodontal infection on the level of hs-CRP in an otherwise healthy Japanese population has not yet been reported. The aim of the present study was to confirm, on a larger scale, our previous pilot study findings that both chronic periodontitis and subsequent periodontal treatment alter the serum levels of C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha).

MATERIAL AND METHODS

The concentrations of serum hs-CRP, IL-6 and TNF-alpha were measured in 78 periodontitis patients at baseline and at re-assessment, and in 40 periodontally healthy subjects at the time of examination.

RESULTS

The concentrations of hs-CRP and IL-6 in the sera of periodontitis patients were significantly higher than those in control subjects. By contrast, the concentration of TNF-alpha was significantly lower in periodontitis patients than in control subjects. Whereas periodontal treatment decreased the levels of serum hs-CRP and IL-6, no such effect was observed for TNF-alpha. When the patients were subdivided into four groups according to their initial concentration of hs-CRP, only the CRP and IL-6 concentrations of the highest quartile group showed a significant reduction following periodontal treatment. No significant difference in the initial clinical parameters was observed in any quartile.

CONCLUSION

Although periodontal infection does affect the concentration of hs-CRP and IL-6 in serum, a subgroup of patients exist who are highly susceptible to an increased risk of CHD associated with periodontitis, suggesting that there may be subjects who have an elevated risk of CHD independent of susceptibility to periodontal tissue destruction per se.

C-reactive protein and coronary heart disease: predictive test or therapeutic target?

BACKGROUND

The hepatocyte-derived acute-phase reactant C-reactive protein (CRP) has been the subject of intense research over the last 2 decades for its possible role in the pathogenesis of cardiovascular diseases. This research has spawned interest in the use of the blood concentration of CRP for predicting a first coronary heart disease (CHD) event, which has been made possible with the development of high-sensitivity CRP (hsCRP) assays that can measure the typically low concentrations of CRP that circulate in the absence of an overt infective or inflammatory episode, and as a potential causal factor that might be targeted therapeutically. The research has encompassed observational and genetic epidemiology, basic science studies with cells and tissues, experiments with animal models and humans, and randomized trials (although not of specific CRP-lowering therapies as yet).

CONTENT

We focus on investigations of the potential role of small differences in basal hsCRP concentration seen in healthy individuals and the relationship of such differences to the long-term risk of a first CHD event, rather than on research devoted to the high acute-phase CRP concentrations, which occur after acute atherothrombotic events and can influence the severity of ischemic tissue damage and the subsequent prognosis. We concentrate mainly on research findings at the translational interface and draw on evidence from human observational and genetic epidemiology, as well as from randomized trials.

CONCLUSIONS

As the field matures from one of discovery to an evaluative science, the development of possible clinical applications requires a sharpening of focus on and a critical appraisal of the strengths and deficiencies of the accumulated evidence. Such assessments require attention to both the current state of affairs and the design of future research, so that the existing uncertainties about the utility of CRP in predicting CHD and its role in causing this disease can be resolved.

Impact of genetic and environmental factors on hsCRP concentrations and response to therapeutic agents

BACKGROUND

Inflammation plays an instrumental role in all stages of atherosclerosis. High-sensitivity C-reactive protein (hsCRP), a systemic inflammatory marker, has been gaining recognition as an independent risk factor for cardiovascular disease (CVD). Both baseline hsCRP concentrations and drug-induced hsCRP changes are highly variable and potentially subject to genetic regulation.

CONTENT

This review summarizes the current studies examining the effect of genetic and environmental factors on baseline plasma hsCRP concentrations, with a main focus on C-reactive protein, pentraxin-related (CRP) genetic polymorphisms and various dietary components that affect hsCRP concentrations. We also address the association of CRP genetic variations with CVD risk, a relationship that may support or refute the causality of CRP in the atherosclerotic process. Moreover, we discuss the impact of CRP genetic polymorphisms on hsCRP changes in response to 3-week fenofibrate treatment in the genetic intervention of the Genetics of Lipid Lowering Drugs and Diet Network study.

SUMMARY

Genetic variants on the CRP locus and other loci and dietary and lifestyle factors are responsible for the interindividual variability of plasma hsCRP concentrations. CRP genetic variants further influence differing plasma hsCRP response after 3-week fenofibrate treatment in patients with metabolic syndrome. Future studies focusing on the influence and interaction of genetic variation on the hsCRP response to dietary and other behavior modification as well as drug treatment could have important implications for the development of more personalized preventive and therapeutic approaches to reduce CVD.

Association between the AGTR1 polymorphism +1166A>C and serum levels of high-sensitivity C-reactive protein

Genetic factors have been shown to influence high-sensitivity C-reactive protein (hsCRP) levels, however, which genes that are involved in this process remains to be clarified. The renin-angiotensin system (RAS) is of importance for the regulation of inflammation, and blockade of angiotensin II type 1 receptors (AGTR1) influences hsCRP levels. These findings prompted us to investigate whether a polymorphism in the AGTR1 gene may influence hsCRP levels. Additionally, a polymorphism in the CRP gene that has previously been shown to influence hsCRP levels was genotyped. Serum levels of hsCRP were measured in 270 42-year-old women recruited from the population registry. Two single nucleotide polymorphisms were analysed: +1166A>C and +1444C>T of the AGTR1 and CRP gene, respectively. The A allele of the AGTR1 polymorphism +1166A>C was dose-dependently associated with higher hsCRP levels (p=0.014, adjusted for confounding factors and multiple comparisons). hsCRP levels were not significantly influenced by the CRP +1444C>T genotype; however, an interaction between the two studied polymorphisms with respect to hsCRP levels was observed (p=0.018). The significant association between the AGTR1 polymorphism and hsCRP levels, which appears to be independent of anthropometric and metabolic traits, is yet another indication of a direct influence of RAS on inflammation.

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.

The association of C-reactive protein and CRP genotype with coronary heart disease: findings from five studies with 4,610 cases amongst 18,637 participants

Background

It is unclear whether C-reactive protein (CRP) is causally related to coronary heart disease (CHD). Genetic variants that are known to be associated with CRP levels can be used to provide causal inference of the effect of CRP on CHD. Our objective was to examine the association between CRP genetic variant +1444C>T (rs1130864) and CHD risk in the largest study to date of this association.

Methods and Results

We estimated the association of CRP genetic variant +1444C>T (rs1130864) with CRP levels and with CHD in five studies and then pooled these analyses (N = 18,637 participants amongst whom there were 4,610 cases). CRP was associated with potential confounding factors (socioeconomic position, physical activity, smoking and body mass) whereas genotype (rs1130864) was not associated with these confounders. The pooled odds ratio of CHD per doubling of circulating CRP level after adjustment for age and sex was 1.13 (95%CI: 1.06, 1.21), and after further adjustment for confounding factors it was 1.07 (95%CI: 1.02, 1.13). Genotype (rs1130864) was associated with circulating CRP; the pooled ratio of geometric means of CRP level among individuals with the TT genotype compared to those with the CT/CC genotype was 1.21 (95%CI: 1.15, 1.28) and the pooled ratio of geometric means of CRP level per additional T allele was 1.14 (95%CI: 1.11, 1.18), with no strong evidence in either analyses of between study heterogeneity (I² = 0%, p>0.9 for both analyses). There was no association of genotype (rs1130864) with CHD: pooled odds ratio 1.01 (95%CI: 0.88, 1.16) comparing individuals with TT genotype to those with CT/CC genotype and 0.96 (95%CI: 0.90, 1.03) per additional T allele (I²<7.5%, p>0.6 for both meta-analyses). An instrumental variables analysis (in which the proportion of CRP levels explained by rs1130864 was related to CHD) suggested that circulating CRP was not associated with CHD: the odds ratio for a doubling of CRP level was 1.04 (95%CI: 0.61, 1.80).

Conclusions

We found no association of a genetic variant, which is known to be related to CRP levels, (rs1130864) and having CHD. These findings do not support a causal association between circulating CRP and CHD risk, but very large, extended, genetic association studies would be required to rule this out.

Systemic host immuno-inflammatory response to dental extractions and periodontitis

OBJECTIVES

Little is known about the host immuno-inflammatory response to dental extractions. The purpose of this pilot clinical study was to explore the effect of both periodontitis and dental extractions on the host systemic immuno-inflammatory response.

STUDY DESIGN

We recruited and collected baseline blood samples on 41 essentially healthy patients. A subset of 22 subjects underwent single (n = 11) or multiple (n = 11) tooth extractions with additional blood samples taken at 1 hour following single tooth extraction and at 8 and 24 hours following multiple tooth extractions. Samples were used for determination of an array of 12 cytokines known to play key roles in innate and adaptive immunity.

RESULTS

There was no significant difference in cytokine levels between the pre- and post-tooth extraction samples for either extraction group for the time points measured. Nor was there a positive relationship between the level of any of the cytokines and periodontal disease status as measured by mean probing depths and other periodontal disease parameters.

CONCLUSION

Our pilot data suggest that the body is well adjusted to deal with the inflammation and bacteremia associated with dental extractions and periodontal disease.

Association of common C-reactive protein (CRP) gene polymorphisms with baseline plasma CRP levels and fenofibrate response: the GOLDN study

OBJECTIVE

C-reactive protein (CRP) is an inflammatory marker that contributes to the prediction of cardiovascular disease. We investigated the influences of CRP polymorphisms on baseline CRP levels and fenofibrate-induced CRP changes in subjects with the metabolic syndrome.

RESEARCH DESIGN AND METHODS

We examined the association of CRP single nucleotide polymorphisms (SNPs) (m772A>G, m301G>A >T, i178T>A, 3u1273C>T, and 3u2131C>T) with baseline plasma CRP levels among 1,123 white U.S. participants in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) Study and the modulating effect of these SNPs on CRP response to a 3-week fenofibrate treatment among 290 participants with the metabolic syndrome.

RESULTS

There were strong associations of m301G>A>T (rs3091244; P = 0.003), i178T>A (rs1417938; P = 0.001), 3u1273C>T (rs1130864; P = 0.001), and 3u2131C>T (rs1205; P < 0.001) with baseline CRP levels. Moreover, among subjects with the metabolic syndrome, fenofibrate induced the greatest reduction in CRP levels for TT subjects of the i178T>A compared with TA and AA subjects (-30 for TT, -19 for TA, and -11% for AA; P = 0.004). Similarly, for the m301G>A>T, major allele carriers displayed maximal reduction of CRP over noncarriers (-20 for GG, -15 for GA and GT, and -0.3% for TA and AA; P = 0.020).

CONCLUSIONS

Our results demonstrate that common genetic variants within the CRP gene affect baseline CRP levels and further modulate CRP response in subjects with the metabolic syndrome treated with fenofibrate. This knowledge could contribute to a better prediction of therapeutic success.

Association between serum levels of C-reactive protein and personality traits in women

BACKGROUND

While low-grade inflammation has consistently been observed in subjects with depression, studies on the possible relationship between inflammation and other aspects of brain function are as yet sparse. In this study, we aimed to investigate the possible association between serum levels of the inflammation marker C-reactive protein (CRP) and personality traits.

METHODS

In this study, serum levels of high-sensitivity CRP were determined by ELISA in a population of 270 42-year-old women recruited from the population registry who had been assessed using the Temperament and Character Inventory. Self-reported previous or ongoing depression was also recorded. Unpaired two-tailed t-tests were used for comparison between two groups and correlations were evaluated by the calculation of Pearson's r-coefficient.

RESULTS

The temperament trait harm avoidance was positively (r = 0.227, p < 0.05) and the character trait self-directedness was negatively (r = -0.261, p < 0.01) associated with serum levels of CRP (p-values corrected for multiple comparisons). The correlations between the personality traits and CRP were observed also after exclusion of subjects reporting ongoing depression (n = 26). Whereas women reporting ongoing depression showed significantly increased levels of CRP as compared to non-depressed women (n = 155), women reporting a history of depression displayed no significant difference in CRP levels as compared to women that reported that they had never been depressed.

CONCLUSION

Serum levels of CRP in women was found to be associated with the personality traits harm avoidance and self-directedness. In addition, moderately elevated levels may be a state dependent marker of depression.

Association of serum interleukin-6 concentration with a functional IL6 -6331T>C polymorphism

BACKGROUND

Interleukin-6 (IL-6) concentrations vary substantially among individuals. This study aimed to identify novel genetic markers to explain these differences.

METHODS

We sequenced a region 6-kb upstream of the IL6 [interleukin 6 (interferon, beta 2)] transcription start site in a search for functional variants and detected 3 common variants: -6331T>C, -6101A>T, and -5617/-5616C/A>T/G. IL6 -6331T>C (C allele frequency, 0.20; 95% confidence interval, 0.16-0.24) showed strong negative linkage disequilibrium with -174G>C (D' = -0.97) and was studied further in 309 individuals who underwent coronary artery bypass grafting.

RESULTS

Patients with the TT genotype had higher IL-6 concentrations 6 h after surgery than those with the CC genotype (mean, 199.4 ng/L vs 114.9 ng/L; P = 0.02). A similar association was seen in a cohort of 173 patients who underwent intensive periodontal therapy: Individuals with the CC genotype had significantly lower IL-6 concentrations 24 h after therapy than TT patients (mean, 0.78 ng/L vs 5.00 ng/L; P < 0.0001). A similar trend was observed in 203 healthy individuals from northern Europe (1.29 ng/L for the TT genotype vs 0.89 ng/L for the CC genotype; P = 0.07). Reporter assays that used a sequence flanking the -6331 single-nucleotide polymorphism spliced upstream to the IL-6 minimal promoter driving luciferase gene expression demonstrated a 1.3-fold increase in promoter activity (P < 0.01) for constructs containing -6331T. Electrophoretic mobility shift assays revealed enhanced binding of transcription factor Oct-1 to the T allele.

CONCLUSIONS

IL6 -6331T is associated with increased IL-6 concentrations in an acute inflammatory state via a mechanism involving binding of the Oct-1 transcription factor. This finding may help resolve conflicting studies based on the IL6 -174G>C variant.

1059G/C polymorphism within the exon 2 of the C-reactive protein gene: relationship to C-reactive protein levels and prognosis in unstable angina

OBJECTIVE

Patients with unstable angina (UA) and high C-reactive protein (CRP) have increased cardiovascular risk. Whether genetic factors such as the synonymous 1059G/C polymorphism within the exon 2 of the human CRP gene determine CRP levels and outcome is unclear.

METHODS

In 105 consecutive patients with UA, we assessed the CRP 1059G/C polymorphism, CRP plasma levels and interleukin-6 production after in-vitro stimulation of whole blood with lipopolysaccharide (1 ng/ml). Coronary events during a 24-month follow-up were recorded.

RESULTS

CRP levels (median, range) were significantly lower among C-allele carriers (2.3 mg/l, 0.5-26.9) than among GG homozygotes (5.9 mg/l, 0.8-72.12, P=0.009). Interleukin-6 production was lower in C-allele carriers (1645 pg/ml, 832.0-9522) than in GG homozygotes (3929 pg/ml, 670.8-10 582), (P=0.085). At follow-up, 1059C-allele carriers experienced fewer coronary events than 1059GG homozygotes (13 vs. 47%, P=0.021). At multivariable analysis, a CRP level >3 mg/l, but not the 1059G/C polymorphism, was an independent predictor of coronary events (odds ratio 10.04, 95% confidence interval 2.84-35.44, P=0.0002).

CONCLUSION

This study shows that the CRP synonymous 1059G/C polymorphism affects CRP levels. No independent association was, however, observed between this polymorphism and clinical outcome in UA.

Genome-wide association with select biomarker traits in the Framingham Heart Study

BACKGROUND

Systemic biomarkers provide insights into disease pathogenesis, diagnosis, and risk stratification. Many systemic biomarker concentrations are heritable phenotypes. Genome-wide association studies (GWAS) provide mechanisms to investigate the genetic contributions to biomarker variability unconstrained by current knowledge of physiological relations.

METHODS

We examined the association of Affymetrix 100K GeneChip single nucleotide polymorphisms (SNPs) to 22 systemic biomarker concentrations in 4 biological domains: inflammation/oxidative stress; natriuretic peptides; liver function; and vitamins. Related members of the Framingham Offspring cohort (n = 1012; mean age 59 +/- 10 years, 51% women) had both phenotype and genotype data (minimum-maximum per phenotype n = 507-1008). We used Generalized Estimating Equations (GEE), Family Based Association Tests (FBAT) and variance components linkage to relate SNPs to multivariable-adjusted biomarker residuals. Autosomal SNPs (n = 70,987) meeting the following criteria were studied: minor allele frequency > or = 10%, call rate > or = 80% and Hardy-Weinberg equilibrium p > or = 0.001.

RESULTS

With GEE, 58 SNPs had p < 10(-6): the top SNPs were rs2494250 (p = 1.00*10(-14)) and rs4128725 (p = 3.68*10(-12)) for monocyte chemoattractant protein-1 (MCP1), and rs2794520 (p = 2.83*10(-8)) and rs2808629 (p = 3.19*10(-8)) for C-reactive protein (CRP) averaged from 3 examinations (over about 20 years). With FBAT, 11 SNPs had p < 10(-6): the top SNPs were the same for MCP1 (rs4128725, p = 3.28*10(-8), and rs2494250, p = 3.55*10(-8)), and also included B-type natriuretic peptide (rs437021, p = 1.01*10(-6)) and Vitamin K percent undercarboxylated osteocalcin (rs2052028, p = 1.07*10(-6)). The peak LOD (logarithm of the odds) scores were for MCP1 (4.38, chromosome 1) and CRP (3.28, chromosome 1; previously described) concentrations; of note the 1.5 support interval included the MCP1 and CRP SNPs reported above (GEE model). Previous candidate SNP associations with circulating CRP concentrations were replicated at p < 0.05; the SNPs rs2794520 and rs2808629 are in linkage disequilibrium with previously reported SNPs. GEE, FBAT and linkage results are posted at http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?id=phs000007 webcite.

CONCLUSION

The Framingham GWAS represents a resource to describe potentially novel genetic influences on systemic biomarker variability. The newly described associations will need to be replicated in other studies.

C-Reactive Protein Gene Polymorphisms, C-Reactive Protein Blood Levels, and Cardiovascular Disease Risk

C-reactive protein (CRP), a blood marker of inflammation and a hallmark of the acute-phase response, has been shown to be a powerful and specific predictor of cardiovascular event risk in populations of otherwise healthy persons. Here we review what is known about CRP gene polymorphisms, discuss how these might affect the epidemiology of CRP and our understanding of CRP's contribution to cardiovascular disease, and examine their potential clinical usefulness. Evidence shows that certain subtle variations in the CRP gene sequence, mostly single nucleotide polymorphisms, predictably and strongly influence the blood level of CRP. Some of these variations are associated with clinical correlates of cardiovascular disease. If future studies can establish with certainty that CRP influences cardiovascular biology, then CRP gene profiling could have clinical utility.

The relationship between gene polymorphism and CRP level in a Chinese Han population

We investigated the relationships among the +1444C/T polymorphism in the C-reactive protein (CRP) gene and the concentration of CRP and the risk of coronary heart disease. Using polymerase chain reaction-restriction fragment length polymorphism, we analyzed the frequency distribution of genotypes and alleles of the +1444C/T polymorphism in samples from 128 patients with coronary heart disease (coronary stenosis more than 50%) and 119 unrelated normal individuals. The plasma levels of CRP and lipids in the subjects were also measured. The frequencies of the genotypes were CC 89.1%, CT 10.9%, and TT 0% in patients and CC 89.9%, CT 10.1%, and TT 0% in controls. The frequency of allele C was 94.5% in patients and 95.0% in controls, and allele T was 5.5% in patients and 5.1% in controls. The distribution of genotypes and alleles in the Chinese Han population was significantly different from that of the Caucasian population. There were no significant differences between frequencies of genotype and allele of controls and those of patients (P>0.05), but in controls the concentrations of CRP in the CC genotype subgroup were significantly higher than those in the CT genotype subgroup (P<0.05). This suggests that the +1444C/T variant in the CRP gene influences the basal CRP level in normal people. These findings imply that there may eventually be a need to establish genotype-specific risk thresholds of the CRP level.

Influence of genetic variation in the C-reactive protein gene on the inflammatory response during and after acute coronary ischemia

The aim of this research was to assess whether common genetic variants within the C-reactive protein gene (CRP) are related to the degree of acute rise in plasma C-reactive protein (CRP) levels following an acute coronary syndrome (ACS). While polymorphisms within CRP are associated with basal CRP levels in healthy men and women, less is known about the relationship of such genetic variants and the degree of CRP rise during and after acute ischemia. Plasma CRP is associated with increased rates of recurrent coronary events. We evaluated seven common genetic variants within CRP and assessed their relationship to the degree of rise in CRP levels immediately following an acute coronary syndrome in 1827 European American patients. Variants in the putative promoter region, -757T > C and -286C > T > A, were associated with the highest CRP elevations after ACS. Patients with two copies of the A allele of SNP -286C > T > A had median CRP values of 76.6 mg/L, compared to 11.1 mg/L in patients with no copies of the rare variant (p-value <0.0001), post ACS. The lowest CRP values were found for patients with minor alleles of the exonic 1059G > C and the 3'untranslated region 1846G > A SNPs. For example, patients homozygous for the minor allele of 1059G > C had 71% lower median CRP values than those homozygous for the major allele [3.5 vs 12.0 mg/L, p < 0.0001]. These trends persisted in the chronic stable phase after ischemia had resolved, and after adjustment for infarct size by peak creatinine kinase levels and clinical status by Killip class. Assessment of CRP genetic variants identified patients with higher and lower CRP elevation after acute coronary syndrome.

Additive effect of interleukin-6 and C-reactive protein (CRP) single nucleotide polymorphism on serum CRP concentration and other cardiovascular risk factors

BACKGROUND

Serum C-reactive protein (CRP) levels, closely associated with cardiovascular disease (CVD) risk are influenced by CRP or interleukin-6 (IL-6) single nucleotide polymorphism (SNPs). However, it is still controversial. Therefore, we investigated the association of IL-6/CRP SNPs and serum CRP levels or other CVD risk factors in healthy adult Korean men.

METHODS

In healthy adult men (age>or=20 years, n=677), we genotyped IL-6-572C>G and CRP SNPs (-717G>A, 1444C>T, 2147A>G) and measured anthropometric parameters, lipid profile, serum levels of CRP and IL-6 and insulin resistance.

RESULTS

At IL-6-572C>G (n=677), subjects with G/G genotype (n=42) showed higher concentrations of CRP (P=0.027) and IL-6 (P=0.028) as compared with C allele carriers after age-adjustment (C/C: n=371, C/G: n=264). Fasting insulin and homeostatis model assessment insulin resistance (HOMA-IR) were also higher in G/G genotype. However, there were no significant differences in other metabolic biomarkers. Among 677 study subjects, 676 were genotyped at CRP-717G>A (G/G: n=513, G/A: n=150, A/A: n=13), 672 at CRP+1444C>T (C/C: n=580, C/T: n=85, T/T: n=7), and 668 at CRP+2147A>G (A/A: n=273, A/G: n=296, G/G: n=99). There were no significant differences in CRP concentrations and other markers related to CVD risk according to each CRP SNP genotype. However, we could find the additive gene-gene interaction between IL-6-572C>G and CRP SNPs on CRP concentration; subjects with the 'G/G' at IL-6-572 showed the highest CRP levels when they have variant allele at CRP SNPs after adjusted for age, body mass index, cigarette smoking and alcohol drinking (-717G>A: F=7.806, P=0.005; CRP+1444C>T: F=8.398, P=0.004; and CRP+2147A>G: F=7.564, P=0.006, respectively) Particularly, G allele carriers at CRP+2147A>G in subjects with IL-6-572G/G showed highest HOMA-IR (F=9.092, P=0.003).

CONCLUSION

The present data showed that serum CRP levels and other CVD risk factors appeared more influenced by IL-6-572C>G rather than CRP SNPs (-717G>A, 1444C>T, and 2147A>G), however CRP levels and insulin resistance may be additively affected by IL-6-572 and CRP SNP, particularly when subjects with G/G genotype at IL-6-572 have allele variant at CRP SNPs.

C-reactive protein 3′ UTR +1444C>T polymorphism in patients with spontaneous venous thromboembolism

OBJECTIVE

Data on C-reactive protein (CRP) as a risk indicator of venous thromboembolism are conflicting. A recent study reported higher CRP levels in homozygous carriers of a novel CRP gene polymorphism at the 3' UTR (CRP +1444C>T). We investigated, whether homozygosity for CRP +1444C>T is associated with an increased risk of spontaneous venous thromboembolism (VTE).

METHODS AND RESULTS

CRP +1444C>T genotype and plasma levels were assessed in 128 patients with deep venous thrombosis (DVT, 70 females/58 males), 105 with pulmonary embolism (PE, 58 females/47 males) and 122 healthy individuals (60 females/62 males). CRP +1444TT was significantly associated with increased CRP plasma levels in healthy individuals. CRP +1444TT was more frequent (14%) among controls than DVT patients (9%, p=0.26) or PE patients (6%, p=0.05), respectively. No significant deviation from Hardy-Weinberg equilibrium was observed in patients (p=0.8) or controls (p=0.3), respectively. CRP +1444C>T was not significantly associated with CRP levels in patients with VTE.

CONCLUSIONS

Homozygous carriers of the CRP 3' UTR +1444C>T polymorphism do not have a significantly increased risk of VTE. Our data support the assumption that a clinically relevant association between CRP and VTE is missing.

The C-reactive protein (+)1444C/T alteration modulates the inflammation and coagulation response in human endotoxemia

BACKGROUND

C-reactive protein (CRP) plays a major role in the immune system and is an independent risk marker of cardiovascular disease. However, CRP's role in atherogenesis as innocent bystander, causative, or even protective agent, remains unresolved. The (+)1444C/T alteration in the CRP gene has been reported to determine basal CRP concentrations. We hypothesized that this alteration may also be associated with the degree of inflammatory response and coagulation activation in a well-standardized model of systemic inflammation.

METHODS

We administered 2 ng/kg endotoxin [Escherichia coli bacterial lipopolysaccharide (LPS)] intravenously to stimulate inflammation in 91 healthy young Caucasian male paid volunteers (age range, 19-40 years). Participants were confined to bed rest and fasted for 8.5 h after LPS infusion. We collected blood samples before LPS infusion and at 0, 2, 6, and 24 h after LPS infusion to measure inflammation markers [interleukin 6 (IL6), tumor necrosis factor-alpha (TNFalpha)], temperature, and coagulation markers (prothrombin fragment F(1+2), D-dimer). We analyzed the CRP 3' untranslated variant with a mutagenic separated PCR assay.

RESULTS

Basal concentrations of high-sensitivity CRP were approximately 40% lower in (+)1444CC alteration carriers than in T homozygous (TT) allele carriers (P = 0.04). In contrast, basal IL6 concentrations were 2-fold higher in wild-type C homozygous (CC) than in TT individuals (P = 0.01). In response to the LPS challenge, CC individuals had 4-fold higher peak TNFalpha concentrations (P <0.01), >2.5-fold higher peak IL6 concentrations (P <0.01), and increased temperature (P <0.01). Twenty-four hours after LPS challenge, prothrombin fragment F(1+2) concentrations were 75% higher and D-dimer concentrations 50% higher in CC than in TT individuals (P <0.05).

CONCLUSIONS

Genetic factors regulating CRP concentrations also modulate the individual response to endotoxin-stimulated inflammation.

Relationship of five inflammatory gene polymorphisms with morbidity and mortality in 533 patients admitted to an ICU

BACKGROUND

The aim of this study was to analyze the association of polymorphisms of five candidate genes with the outcome of consecutive patients admitted to a medical ICU.

MATERIALS AND METHODS

The study population was prospectively recruited. Inclusion criteria were admission to the ICU and written informed consent by the patients or their relatives. A total of 533 patients were recruited. The morbidity was assessed by SAPS II Score. Outcome data of in hospital mortality and length of ICU and hospital stay were obtained. Genotyping for genetic polymorphisms (CRP 1059, IL1B -511, CTGF -477, CCR2 64VI, IL6 -174) were performed by allele-specific fluorogenic oligonucleotide probes (TaqMan analysis).

RESULTS

All of the investigated polymorphisms were not associated with an altered outcome. There was no difference in morbidity and ICU or in-hospital mortality (neither in cross tabs analysis nor in Kaplan Meier or Cox regression analysis including age, gender and diagnosis as covariates) between the different genotypes.

CONCLUSIONS

Genotyping of the investigated polymorphism for risk stratification of patients admitted to ICU does not seem to be appropriated.

C-reactive protein in patients with coexistent periodontal disease and acute coronary syndromes

AIM

To evaluate periodontal disease (PD) influence on changes in high-sensitivity C-reactive protein (hsCRP) concentrations in patients with acute coronary syndromes and coexistent PD.

MATERIALS AND METHODS

Dental examinations were carried out in a group of 50 consecutive patients, less than 60 years old, hospitalized as a result of acute coronary syndromes. The patients were divided into two groups on the basis of own-constructed combined PD score (group 2: more advanced; and group 1: less advanced PD) as well as clinical attachment loss (CAL) - group 4: CAL >3 mm; group 3: CAL <or=3 mm. Blood samples for hsCRP estimation were taken at admission, after 10/12 days and long term after acute coronary syndromes.

RESULTS

A statistically significant decrease in hsCRP was observed among three consecutive blood sample examinations in groups 2 and 4, whereas it was only seen between examination 1 and examination 2 in groups 1 and 3.

CONCLUSIONS

Although no statistically significant difference of hsCRP was found between studied groups, patients with less advanced PD, either estimated with the use of own-constructed combined score or on the basis of CAL, have significantly longer diminution of inflammatory response monitored with hsCRP concentrations.

C-reactive protein gene haplotypes and risk of coronary heart disease: the Rotterdam Study

AIMS

C-reactive protein is associated with risk of cardiovascular disease. However, whether C-reactive protein is a marker of severity of cardiovascular disease or actually is involved in its pathogenesis remains unknown. We investigated the relation between C-reactive protein haplotypes, representing the comprehensive variation of the C-reactive protein gene, and coronary heart disease.

METHODS AND RESULTS

The Rotterdam Study is a prospective population-based study among men and women aged 55 years and older. C-reactive protein was associated with risk of coronary heart disease, with a multivariable adjusted hazard ratio of 1.9 (95% CI 1.5-2.4) for the highest vs. the lowest quartile. Four C-reactive protein haplotypes were present with overall frequencies of 32.8, 31.7, 29.5, and 5.9%. C-reactive protein serum levels were significantly different according to C-reactive protein haplotypes. C-reactive protein haplotypes were not associated with coronary heart disease.

CONCLUSION

Steady-state C-reactive protein serum level is influenced by C-reactive protein gene haplotypes. Although elevated C-reactive protein level has lately been found to be a consistent and relatively strong risk factor for cardiovascular disease, our study does not support that the common variation in the C-reactive protein gene has a large effect on the occurrence of coronary heart disease.

Insight into the nature of the CRP-coronary event association using Mendelian randomization

BACKGROUND

It is unclear wheather the association between C-reactive protein (CRP) and incident coronary events is free from bias and confounding. Individuals homozygous for a +1444C>T polymorphism in the CRP gene have higher circulating concentrations of CRP. Since the distribution of this polymorphism occurs at random during gamete formation, its association with coronary events should not be biased or confounded.

METHODS

We calculated the weighted mean difference in CRP between individuals with variants of the +1444C>T polymorphism in the CRP gene among 4,659 European men from six studies (genotype-intermediate phenotype studies). We used this difference together with data from previous observational studies to compute an expected odds ratio (OR) for non-fatal myocardial infarction (MI) among individuals homozygous for the T allele. We then performed four new genetic association studies (6,201 European men) to obtain a summary OR for the association between the +1444C>T polymorphism and non-fatal MI (genotype-disease studies).

RESULTS

CRP was 0.68 mg/l [95% confidence interval (95% CI) 0.31-1.10; P = 0.0001] higher among subjects homozygous for the +1444-T allele, with no confounding by a range of covariates. The expected ORs among TT subjects for non-fatal MI corresponding to this difference in CRP was 1.20 (95% CI 1.07-1.38) using the Reykjavik Heart study data and 1.25 (1.09-1.43) for all observational studies to 2004. The estimate for the observed adjusted-OR for non-fatal MI among TT subjects was 1.01 (95% CI 0.74-1.38), lower than both expected ORs.

CONCLUSIONS

A common CRP gene polymorphism is associated with important differences in CRP concentrations, free from confounding. The null association of this variant with coronary events suggests possible residual confounding (or reverse causation) in the CRP-coronary event association in observational studies, though the confidence limits are still compatible with a modest causal effect. Additional studies of genotype (or haplotype) and coronary events would help clarify whether or not the link between CRP and coronary events in observational studies is causal.

C-reactive protein and cardiovascular disease: a critical appraisal

PURPOSE OF REVIEW

C-reactive protein, a nonspecific marker of inflammation, has recently been proposed both as a marker of low-grade inflammation involved in atherogenesis and as a predictor of disease progression.

RECENT FINDINGS

The physiologic functions of C-reactive protein as an anti-inflammatory scavenger molecule have begun to emerge. For example, C-reactive protein binds to damaged lipoproteins and facilitates their removal by phagocytes without full complement activation. Increased levels of C-reactive protein may result in direct effects on vascular cells, including induction of cytokines and prothrombotic factors. Several sources of biologic variation in the levels of C-reactive protein have been identified, chief among which are abdominal obesity and the metabolic syndrome. Although previous studies showed a potent independent association of C-reactive protein levels with cardiac events, the strength of association was shown to be much weaker than previously reported in recent large meta-analyses. Therapy with nonspecific anti-inflammatory agents such as statins in patients with coronary artery disease has been found to reduce adverse outcomes in association with reductions in C-reactive protein, on the basis of retrospective analysis of stored blood specimens.

SUMMARY

Despite a relatively strong epidemiologic association with future adverse cardiovascular events, the great majority of apparently healthy individuals with elevated C-reactive protein will not experience cardiovascular disease. Even though more than 15 000 articles in PubMed mention C-reactive protein, current knowledge is insufficient to implicate C-reactive protein as a causative factor in atherothrombosis or to enable the recommendation of C-reactive protein testing to guide preventive or therapeutic interventions in cardiovascular diseases.

Periodontal diseases

The periodontal diseases are highly prevalent and can affect up to 90% of the worldwide population. Gingivitis, the mildest form of periodontal disease, is caused by the bacterial biofilm (dental plaque) that accumulates on teeth adjacent to the gingiva (gums). However, gingivitis does not affect the underlying supporting structures of the teeth and is reversible. Periodontitis results in loss of connective tissue and bone support and is a major cause of tooth loss in adults. In addition to pathogenic microorganisms in the biofilm, genetic and environmental factors, especially tobacco use, contribute to the cause of these diseases. Genetic, dermatological, haematological, granulomatous, immunosuppressive, and neoplastic disorders can also have periodontal manifestations. Common forms of periodontal disease have been associated with adverse pregnancy outcomes, cardiovascular disease, stroke, pulmonary disease, and diabetes, but the causal relations have not been established. Prevention and treatment are aimed at controlling the bacterial biofilm and other risk factors, arresting progressive disease, and restoring lost tooth support.