TLR4/Asp299Gly, CD14/C-260T, plasma levels of the soluble receptor CD14 and the risk of coronary heart disease: The PRIME Study

Soluble CD14 and Osteoprotegerin Associate with Ankle-Brachial Index as a Measure of Arterial Stiffness in Patients with Mild-to-Moderate Chronic Kidney Disease in a Five-Year Prospective Study

INTRODUCTION

Vascular lesions and arterial stiffness appear at early stages of chronic kidney disease (CKD) and follow an accelerated course with disease progression, contributing to high cardiovascular mortality. There are limited prospective data on mechanisms contributing to progression of arterial stiffness in mild-to-moderate CKD (stages 2-3).

METHODS

We applied an affinity proteomics approach to identify candidates of circulating biomarkers with potential impact on vascular lesions in CKD and selected soluble cluster of differentiation 14 (sCD14), angiogenin (ANG), and osteoprotegerin (OPG) for further analysis. We studied their association with ankle-brachial index (ABI) and carotid intima-media thickness, as measures of arteriosclerosis and atherosclerosis, respectively, in 48 patients with CKD stages 2-3, who were prospectively followed and intensively treated for 5 years, and 44 healthy controls.

RESULTS

Concentrations of sCD14 (p < 0.001), ANG (p < 0.001), and OPG (p < 0.05) were higher in patients with CKD 2-3 at baseline, and sCD14 (p < 0.001) and ANG (p < 0.001) remained elevated in CKD patients at follow-up. There were positive correlations between ABI and sCD14 levels (r = 0.36, p = 0.01) and between ABI and OPG (r = 0.31, p = 0.03) at 5 years. The changes in sCD14 during follow-up correlated to changes in ABI from baseline to 5 years (r = 0.41, p = 0.004).

CONCLUSION

Elevated levels of circulating sCD14 and OPG in patients with CKD 2-3 were significantly associated with ABI, a measure of arterial stiffness. An increase in sCD14 over time in CKD 2-3 patients was associated with a corresponding increase in ABI. Further studies are needed to examine if early intensive multifactorial medication to align with international treatment targets may influence cardiovascular outcomes.

Increased circulating levels of MIP-1α and CD14 are associated with the presence of severe stenosis and hypoechoic plaques in patients with carotid atherosclerosis

OBJECTIVE

Carotid atherosclerosis, a major cause of ischemic cerebrovascular events, is characterized by a pro-inflammatory and pro-oxidant vascular microenvironment. The current risk score models based on traditional risk factors for cardiovascular risk assessment have some limitations. The identification of novel blood biomarkers could be useful to improve patient management. The aim of the study was to evaluate the association of selected inflammation- and oxidative stress-related markers with the presence of severe stenosis and/or vulnerable plaques.

METHODS

Circulating levels of soluble CD40 ligand, interleukin-10, macrophage inflammatory protein (MIP)-1α, endoglin, CD163, CD14, E-selectin, tumor necrosis factor-α, monocyte chemoattractant protein-1, C-Reactive protein, CD40 L + T lymphocytes, total antioxidant capacity, glutathione reductase activity, and protein carbonyl content were determined in patients with carotid atherosclerosis.

RESULTS

Multiparametric analysis showed significantly higher levels of MIP-1α in patients with stenosis ≥70% than in patients with stenosis <70%, and significantly higher levels of CD14 in patients with hypoechoic (vulnerable) lesions compared to those with hyperechoic (stable) ones. The area under the curve obtained by the receiver operating characteristic curve analysis was 0.7253 for MIP-1α and 0.6908 for CD14.

CONCLUSIONS

Our data suggest that circulating MIP-1α and CD14 levels are associated with the presence of advanced stenosis and of vulnerable carotid plaques.

Association of TGFB1 rs1800469 and BCMO1 rs6564851 with coronary heart disease and IL1B rs16944 with all-cause mortality in men from the Northern Ireland PRIME study

BACKGROUND

Historically, high levels of morbidity and mortality have been associated with cardiovascular disease in the Northern Ireland population. Previously reported associations between single nucleotide polymorphisms (SNPs) and cardiovascular disease within other populations have not always been consistent.

OBJECTIVE

To investigate associations between 33 SNPs with fatal or non-fatal incident coronary heart disease (CHD) events and all-cause mortality in the Northern Irish participants of the Prospective Epidemiological Study of Myocardial Infarction (PRIME).

METHOD

Phase 2 of the PRIME study prospectively evaluated 2,010 men aged 58-74 years in Northern Ireland for more than 10 years for incident CHD events (myocardial infarction, percutaneous coronary intervention, coronary artery bypass, and cardiac death) and more than 15 years for all-cause mortality. SNPs previously reported in association with cardiovascular outcomes were evaluated against incident CHD events and all-cause mortality using Cox's proportional hazards models adjusted for established cardiovascular disease risk factors.

RESULTS

During the follow-up period, 177 incident CHD events were recorded, and 821 men died. Both BCMO1 rs6564851 (Hazard ratio [HR] = 0.76; 95% confidence intervals [CI]: 0.60-0.96; P = 0.02) and TGFB1 rs1800469 (HR = 1.30; CI: 1.02-1.65; P = 0.04) were significantly associated with incident CHD events in adjusted models. Only IL1B rs16944 was significantly associated with all-cause mortality (HR = 1.18; CI: 1.05-1.33; P = 0.005). No associations remained significant following Bonferonni correction for multiple testing.

CONCLUSION

We report a novel association between BCMO1 rs6564851 and risk of incident CHD events. In addition, TGFB1 rs1800469 and IL1B rs16944 were associated with the risk of incident CHD events and all-cause mortality outcomes respectively, supporting previously reported associations.

A Network Pharmacology Study to Explore the Underlying Mechanism of Safflower (Carthamus tinctorius L.) in the Treatment of Coronary Heart Disease

Safflower has long been used to treat coronary heart disease (CHD). However, the underlying mechanism remains unclear. The goal of this study was to predict the therapeutic effect of safflower against CHD using a network pharmacology and to explore the underlying pharmacological mechanisms. Firstly, we obtained relative compounds of safflower based on the TCMSP database. The TCMSP and PubChem databases were used to predict targets of these active compounds. Then, we built CHD-related targets by the DisGeNET database. The protein-protein interaction (PPI) network graph of overlapping genes was obtained after supplying the common targets of safflower and CHD into the STRING database. The PPI network was then used to determine the top ten most significant hub genes. Furthermore, the DAVID database was utilized for the enrichment analysis on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). To validate these results, a cell model of CHD was established in EAhy926 cells using oxidized low-density lipoprotein (ox-LDL). Safflower was determined to have 189 active compounds. The TCMSP and PubChem databases were used to predict 573 targets of these active compounds. The DisGeNET database was used to identify 1576 genes involved in the progression of CHD. The top ten hub genes were ALB, IL6, IL1B, VEGFA, STAT3, MMP9, TLR4, CCL2, CXCL8, and IL10. GO functional enrichment analysis yielded 92 entries for biological process (BP), 47 entries for cellular component (CC), 31 entries for molecular function (MF), and 20 signaling pathways, which were obtained from KEGG pathway enrichment screening. Based on these findings, the FoxO signaling pathway is critical in the treatment of CHD by safflower. The in vitro results showed that safflower had an ameliorating effect on ox-LDL-induced apoptosis and mitochondrial membrane potential. The western blot results showed that safflower decreased Bax expression and acetylation of FoxO1 proteins while increasing the expression of Bcl-2 and SIRT1 proteins. Safflower can be used in multiple pathways during CHD treatment and can exert anti-apoptotic effects by regulating the expression of Bax, Bcl-2, and SIRT1/FoxO1 signaling pathway-related proteins.

Immune correlates of cardiovascular co-morbidity in HIV infected participants from South India

BACKGROUND

Understanding the immune correlates of cardiovascular disease (CVD) risk in HIV infection is an important area of investigation in the current era of aging with HIV infection. Less is known about CVD risk and HIV infection in developing nations where additional risk factors may be playing a role in the CVD development. In this study, we assessed the effects of systemic inflammation, microbial translocation (MT), T cell immune activation (IA), and nadir CD4 counts on cardiac function and arterial stiffness as markers of subclinical atherosclerosis in HIV-infected individuals.

METHODS

People with HIV (PWH) who were ART naïve (n = 102) or virally suppressed on ART (n = 172) were stratified on nadir CD4 counts and compared to HIV-uninfected controls (n = 64). Determination was made of cardiac function via radial pulse wave and carotid intima thickness (C-IMT) measurements. Plasma biomarkers of inflammation and MT by ELISA or multiplex assays, and immune activation (IA) of T cells based HLA-DR and CD38 expression were investigated by flow cytometry. T-test, Mann-Whitney U test, and Spearman correlation were used to analyze study parameters.

RESULTS

Reduction in cardiac function with lower cardiac ejection time (p < 0.001), stroke volume (p < 0.001), cardiac output (p = 0.007), higher arterial stiffness (p < 0.05) were identified in ART-naïve participants, compared to PWH on ART (p < 0.05). No significant difference in C-IMT values were noted. Higher inflammatory and MT markers were found in the ART-naïve group compared to treated group who were comparable to uninfected participants, except for having higher TNF-α (p < 0.001) and sCD14 (p < 0.001). Immune activation of CD4 and CD8 T-cells was greater in ART-naïve participants compared to ART-treated and uninfected controls (p < 0.05). Lower nadir CD4 counts, higher inflammation, and higher MT predicted poor cardiac measures in the ART-naïve with nadir CD4 < 200cells/mm³ manifesting the highest arterial stiffness, and lowest cardiac function, whereas ART-treated, even with nadir < 200 cells/mm³ were similar to uninfected in these measures.

CONCLUSIONS

In HIV-infected individuals, initiation of ART even at nadir of < 200 cells/mm³ may prevent or reverse cardiovascular disease outcomes that are easily measurable in low income countries.

Polymorphism of CD14 Gene Is Associated with Adverse Outcome among Patients Suffering from Cardiovascular Disease

Background

The biological link between severe periodontitis and cardiovascular disease is well established. Both complex inflammatory diseases are influenced by genetic background. Therefore, the impact of genetic variations of receptors of the innate immune system-(Toll-like receptors (TLRs)) TLR2, TLR4, cluster of differentiation 14 (CD14), and the transcription factor nuclear factor-κΒ (NF-κB)-was investigated.

Materials and Methods

In this study (ClinicalTrials.gov identifier: NCT01045070), 1002 cardiovascular (CV) patients were included. In a 3-year follow-up period, new vascular events were assessed. SNPs in CD14 (rs2569190), NF-κΒ (rs28362491), TLR2 (rs5743708), and TLR4 (rs4986790) were genotyped. The impact of these genetic variants on severe periodontitis as well as on CV outcome was assessed.

Results

All investigated genetic variants were not associated with preexisting CV events or severe periodontitis in CV patients. In Kaplan-Meier survival analyses, the CT genotype of CD14 single-nucleotide polymorphism (SNP) rs2569190 was shown to be an independent predictor for combined CV endpoint (log rank: p = 0.035; cox regression; hazard ratio: 1.572; p = 0.044) as well as cardiovascular death (log rank: p = 0.019; cox regression; hazard ratio: 1.585; p = 0.040) after three years of follow-up.

Conclusions

SNPs in CD14, NF-κΒ, TLR2, and TLR4 are no risk modulators for preexisting CV events or severe periodontitis in CV patients. The CT genotype of CD14 SNP rs2569190 provides prognostic value for further CV events within 3 years of follow-up.

Soluble CD14 Levels in the Jackson Heart Study: Associations With Cardiovascular Disease Risk and Genetic Variants

[Figure: see text].

Anti-inflammatory Action of Statins in Cardiovascular Disease: the Role of Inflammasome and Toll-Like Receptor Pathways

Atherosclerosis is one type of cardiovascular disease (CVD) in which activation of the NLRP3 inflammasome and toll-like receptor (TLR) pathways is implicated. One of the most effective treatments for atherosclerosis is the use of statin medications. Recent studies have indicated that statins, in addition to their lipid-lowering effects, exert inhibitory and/or stimulatory effects on the NLRP3 inflammasome and TLRs. Some of the statins lead to activation of the inflammasome and subsequently cause secretion of IL-1β and IL-18. Thus, these actions may further aggravate the disease. On the other hand, some statins cause inhibition of the inflammasome or TLRs and along with lipid-lowering, help to improve the disease by reducing inflammation. In this article, we discuss these contradictory studies and the mechanisms of action of statins on the NLRP3 inflammasome and TLR pathways. The dose-dependent effects of statins on the NLRP3 complex are related to their chemistry, pharmacokinetic properties, and danger signals. Lipophilic statins have more pleiotropic effects on the NLRP3 complex in comparison to hydrophilic statins. Statins can suppress TLR4/MyD88/NF-ĸB signaling and cause an immune response shift to an anti-inflammatory response. Furthermore, statins inhibit the NF-ĸB pathway by decreasing the expression of TLRs 2 and 4. Statins are cost-effective drugs, which should have a continued future in the treatment of atherosclerosis due to both their immune-modulating and lipid-lowering effects.

Soluble CD14, Ischemic Stroke, and Coronary Heart Disease Risk in a Prospective Study: The REGARDS Cohort

Background

Soluble CD14 (sCD14), a circulating pattern recognition receptor, has been suggested as a cardiovascular disease risk factor. Prospective studies evaluating sCD14 with incident cardiovascular disease events are limited, particularly among racially diverse populations.

Methods and Results

Between 2003 and 2007, the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study recruited 30 239 black and white participants across the United States. In a nested case–cohort study, sCD14 was measured in baseline serum from 548 cases of incident ischemic stroke, 612 cases of incident coronary heart disease (CHD), and a cohort random sample (n=1039). Cox models estimated hazards ratios (HR) of incident ischemic stroke or CHD per 1 SD higher sCD14, adjusting for cardiovascular disease risk factors. There was a differential association of sCD14 with ischemic stroke and CHD risk by race. Among blacks, the adjusted HR of stroke per SD increment of sCD14 was 1.42 (95% CI: 1.12, 1.80), with no association among whites (HR 1.02 [95% CI: 0.82, 1.27]). Higher sCD14 was associated with increased CHD risk in blacks but not whites, and relationships between sCD14 and CHD were stronger at younger ages. Adjusted for risk factors, the HR of CHD per SD higher sCD14 among blacks at age 45 years was 2.30 (95% CI: 1.45, 3.65) compared with 1.56 (95% CI: 0.94, 2.57) among whites. At age 65 years, the CHD HR was 1.51 (95% CI: 1.20, 1.91) among blacks and 1.02 (95% CI: 0.80, 1.31) among whites.

Conclusions

sCD14 may be a race‐specific stroke and CHD risk marker.

Effect of CD14 polymorphisms on the risk of cardiovascular disease: evidence from a meta-analysis

Background

CD14 polymorphisms are associated with an increased risk of cardiovascular events. So far, many studies have been conducted, whereas the results were not always consistent.

Materials and methods

Twenty-six articles involving thirty-seven datasets were recruited to evaluate the association between rs2569190 (9413 patients and 7337 controls), C-159T (4813 patients and 2852 controls) polymorphisms and cardiovascular diseases in a meta-analysis. The random or fixed effect models were used to evaluate the pooled odds ratios (ORs) and their corresponding 95% confidence intervals.

Results

The strongest association was observed between rs2569190 and CVD in overall population (T vs. C, OR = 1.169, 95% CI: 1.087–1.257, p = 2.44 × 10^− 5). Analysis after stratification by ethnicity indicated that rs2569190 was related to CVD in East Asian population (T vs. C, OR = 1.370, 95% CI; 1.226–1.531, p = 2.86 × 10^− 8) and a potential relationship in European (T vs. C, OR = 1.100, 95% CI: 1.019–1.189, p = 0.015). In the stratification of endpoints, the associations were found in CHD subgroup (T vs. C, OR = 1.357, 95% CI: 1.157–1.592, p = 2.47 × 10^− 7) and in AMI subgroup (T vs. C, OR = 1.152, 95% CI: 1.036–1.281, p = 0.009). However, we did not find any association between C-159T polymorphism with cardiovascular disease under any model.

Conclusions

The SNP rs2569190 significantly contribute to susceptibility and development of cardiovascular disease, particularly in the East Asian population and in the subtype CHD group, in addition, a potential association was observed in the AMI group, T allele acts as a risk factor for cardiovascular disease.

Electronic supplementary material

The online version of this article (10.1186/s12944-019-1018-3) contains supplementary material, which is available to authorized users.

Association of CD14 and macrophage migration inhibitory factor gene polymorphisms with inflammatory microRNAs expression levels in ankylosing spondylitis and polyarthralgia

This study aimed to investigate the genetic basis of ankylosing spondylitis (AS) and polyarthralgia (PA) conditions among Indian subjects through genotyping two immune regulatory genes CD14 (-159C>T) and MIF (-173G>C) and find their association with the expression levels of three circulating inflammatory miRNAs. This investigation may provide early genetic cause of these two forms of arthritis and more optimal biological targets to predict early therapeutic outcomes. A total of 140 patients (AS: 70 and PA: 70) and 156 controls were recruited from Indian population. CD14 and MIF genotyping was performed using ARMS-PCR. Expression level of three inflammatory miRNAs (miRNA-146a, miRNA-155 and miRNA-181) was quantified using RT-qPCR. C/T genotype of CD14 gene was found to cause 2.06-fold risk of developing AS (CI 1.06-5.98, p = .04) as compared to others and G/C genotype in MIF also shown significant variation between AS and control subjects. In PA subjects, CD14 genotypes (C/T) was found to be associated with disease susceptibility and G/C genotype of MIF gene polymorphism showed 4.71-fold risk of developing PA (CI 2.58-8.62, p = .0001). The study also revealed significant upregulation of miRNA-155 expression in AS subjects (p = .0001) with more than 1.3-fold difference between AS and PA as compared to the control subjects. miRNA-155 had strong association with AS patients with CD14 genotypes (p < .05) than PA and control subjects. This study provides better understanding of the mechanisms and disease susceptibility for MIF and CD14 genetic variants and inflammatory miRNAs networks involved in AS and PA.

Association between Toll-like receptor 4 Asp299Gly polymorphism and coronary heart disease susceptibility

Published data on the association between Toll-like receptor 4 (TLR4) Asp299Gly polymorphism and coronary heart disease (CHD) susceptibility are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis was performed. English-language studies were identified by searching PubMed and Embase databases (up to November 2016). All epidemiological studies were regarding Caucasians because no TLR4 Asp/Gly and Gly/Gly genotypes have been detected in Asians. A total of 20 case-control studies involving 14,416 cases and 10,764 controls were included in the meta-analysis. Overall, no significant associations were found between TLR4 Asp299Gly polymorphism and CHD susceptibility in the dominant model (OR=0.89; 95%CI=0.74 to 1.06; P=0.20) pooled in the meta-analysis. In the subgroup analysis by CHD, non-significant associations were found in cases compared to controls. When stratified by control source, no significantly decreased risk was found in the additive model or dominant model. The present meta-analysis suggests that the TLR4 Asp299Gly polymorphism was not associated with decreased CHD risk in Caucasians.

Single Nucleotide Polymorphisms in CD14 and Toll-like Receptor 4 Genes in Patients with Polycystic Ovarian Syndrome

Introduction

Polycystic ovary syndrome (PCOS) is a complex disease having genetic, immunologic, and environmental components, and candidate genes on innate immunity have been hypothesized to be involved in its etiology. We examined the possible association of CD14 and toll-like receptor 4 (TLR4) polymorphisms with PCOS.

Materials and methods

A total of 219 women with PCOS and 272 healthy women were recruited in the study. Their samples were genotyped for the polymorphism of CD14 and TLR4 genes.

Results

The distributions of genotypes of both polymorphisms were found to be significant in women with PCOS compared with controls. The distributions of alleles were also found to be predominant in PCOS compared with controls.

Conclusion

Polymorphisms in CD14-159C>T and TLR4-299A>G significantly increased susceptibility to PCOS. Further studies with larger sample sizes are warranted to confirm these findings.

How to cite this article

Allauddin N, Rozati R. Single Nucleotide Polymorphisms in CD14 and Toll-like Receptor 4 Genes in Patients with Polycystic Ovarian Syndrome. J South Asian Feder Obst Gynae 2017;9(4):304-307.

Genetic association of Toll-like receptor 4 gene and coronary artery disease in a Chinese Han population

PURPOSE

Toll-like receptor 4 (TLR4) is known to be involved in innate immunity and inflammatory responses that play important roles in the pathogenesis of coronary artery disease (CAD). But the relationship between TLR4 gene and CAD has yet to be investigated. The present study aimed to evaluate the association of TLR4 gene polymorphisms with CAD susceptibility in a Chinese Han population.

METHODS

A total of 1094 subjects (577 unrelated patients with CAD and 517 controls) were recruited between 2008 and 2012. Three tag SNPs (rs1927907, rs1927911 and rs11536889) present in the TLR4 gene were genotyped using Sequenom Mass-ARRAY system.

RESULTS

The genotypic distributions of the three SNPs were not deviate from Hardy-Weinberg equilibrium. There was no significant difference in distributions of allelic frequencies of each SNPs between healthy controls and CAD patients (P > 0.05). Genotype frequencies of TLR4 gene did not show any statistically significant difference between the two groups in co-dominant, dominant or recessive genetic models (P > 0.05). The frequency of haplotypes in the case group was similar to that in the control group (P > 0.05).

CONCLUSION

TLR4 gene do not relate to genetic susceptibility of CAD in the Chinese Han population.

CD14 Receptor Gene Promoter Polymorphism: Awakening Maternal Immunity during Pregnancy

We investigated whether monocyte CD14 receptor gene promoter polymorphisms were associated with the development and severity of pre-eclampsia. We genotyped the CD14-260 C/T polymorphism in 36 preeclamptic patients and 52 healthy pregnant controls. A total of 30.6% and 69.4% of pre-eclamptic patients had the C and T alleles, respectively, and 48.0% and 52.0% of the controls, respectively. More pre-eclamptic patients were TT homozygotes compared with controls (50.0% versus 13.5%). In pre-eclamptic patients, the TT homozygotes exhibited a significantly higher mean systolic blood pressure compared with the non-TT homozygotes (173 ± 28 mmHg versus 153 ± 22 mmHg). We also noted a tendency towards increased proteinuria and placental abruption in the TT homozygotes compared with the non-TT homozygotes. We conclude that CD14 gene promoter polymorphisms appear to be a risk factor for pre-eclampsia. With further research, these findings might form the basis of a prognostic tool for pre-eclampsia.

The Link Between Inflammatory Disorders and Coronary Heart Disease: a Look at Recent Studies and Novel Drugs in Development

Inflammation is a critical component in the development of coronary heart disease (CHD), specifically in the process of atherogenesis. Human translational and preclinical studies have demonstrated that inflammation contributes to the development, sustainment, and progression of atherosclerosis, and epidemiological studies demonstrate that human diseases associated with increased systemic inflammation increase the risk of CHD-related events. Therefore, over the last decade, multiple clinical studies were designed to target the inflammatory cascade in order to reduce the risk of CHD and to identify which populations may benefit from these preventative treatment strategies. This review briefly summarizes inflammation as a risk factor in atherosclerosis, human disease states associated with accelerated atherosclerosis, and current treatment strategies for CHD targeting the inflammatory cascade.

TLR-4 and CD14 Genotypes and Soluble CD14: Could They Predispose to Coronary Atherosclerosis?

Background: Inflammatory mechanisms are key to the pathogenesis of atherosclerosis. Functional polymorphisms of TLR-4, Asp299Gly and Thr399Ile, CD14 promoter area C260T polymorphism and plasma levels of soluble CD14 are studied in subjects with Coronary Artery Disease (CAD). Methods: DNA was obtained from 100 human paraffin-embedded aortic specimens, from cadavers with known coronary atheromatosis (Group A) and 100 blood samples from patients with CAD, as detected by cardiac Multi-Detector-row-Computed-Tomography (MDCT) (Group B). Our control group consisted of 100 healthy individuals (Group C). Genotyping was performed by Restriction Fragment Length Polymorphism-Polymerase Chain Reaction (RFLP-PCR). Plasma levels of sCD14 were measured with ELISA. Results: For TLR-4 Asp299Gly and Thr399Ile polymorphisms, no statistically significant differences were observed. Regarding the C260T polymorphism, frequencies of T allele were significantly higher in the control group compared to the case group (p = 0.05). The Odds Ratio (OR) showed statistically significant association of TT genotype with healthy individuals (OR 0.25, 95% Confidence Interval CI 0.10–0.62, p = 0.0017). Plasma levels of sCD14 in patients with CAD (mean value = 1.35 μg/mL) were reduced when compared to reference value. Conclusions: The studied polymorphisms ofTLR-4 showed no association with CAD. Conversely, the functional polymorphism of CD14 has a statistically significant difference in expression between healthy and affected by CAD individuals.

TLR4 Asp299Gly (rs4986790) polymorphism and coronary artery disease: a meta-analysis

Background. Previous studies have shown conflicting results on the association between toll-like receptor 4 (TLR4) Asp299Gly (rs4986790) polymorphism and coronary artery disease (CAD). The aim of this study was to evaluate the influence of TLR4 Asp299Gly polymorphism on CAD risk, CRP level and the number of stenotic coronary arteries, as well as to investigate whether G allele carriers would benefit more from statin treatment. Methods. PubMed, EMBASE, and CNKI databases were searched until May 2015. All the statistical tests were performed using R version 3.1.2. Odds ratio (OR) and 95% confidence interval (CI) were used to assess the association between TLR4 Asp299Gly polymorphism and CAD risk, the number of stenotic vessels, and the incidence of cardiovascular events according to statin-treated patients. Weighted mean difference (WMD) was calculated for the association between Asp299Gly and CRP level. Results. Overall, 12 case-control studies with 10,258 cases and 5,891 controls were included, and no association of TLR4Asp299Gly polymorphism with CAD was found (G allele vs. A allele: OR = 0.97, 95% CI [0.81-1.17], P = 0.75; AA vs. GG + AG: OR = 0.97, 95% CI [0.80-1.18], P = 0.76; GG vs. AG + AA: OR = 1.08, 95% CI [0.57-2.02], P = 0.82; AG vs. AA + GG: OR = 1.03, 95% CI [0.85-1.25], P = 0.74). Also, no association was noted between Asp299Gly and CRP level (WMD = -0.10, 95% CI [-0.62, 0.41], P = 0.69). Furthermore, no synergistic effect of statin and 299Gly was reported (Statin_AA vs. Statin_

AG/GG

OR = 1.12, 95% CI [0.41-3.09], P = 0.82). Discussion. This meta-analysis suggests no association of TLR4 Asp299Gly polymorphism with CAD and CRP level. It is further indicated that the G allele carriers may not benefit more from statin treatment. Further studies should include large sample size and high-quality literature to understand this issue in depth.

The CD14 C-260T single nucleotide polymorphism (SNP) modulates monocyte/macrophage activation in treated HIV-infected individuals

Background

HIV-infected individuals have an increased risk of cardiovascular disease (CVD). T-allele carriers of the CD14 C-260T single-nucleotide polymorphism (SNP) have reported increased expression of the LPS-binding receptor, CD14 and inflammation in the general population. Our aim was to explore the relationship of this SNP with monocyte/macrophage activation and inflammation and its association with sub-clinical atherosclerosis in HIV-infected individuals.

Methods

Patients with no pre-existing CVD risk factors on suppressive antiretroviral therapy were recruited from University Malaya Medical Centre, Malaysia (n = 84). The CD14 C-260T and TLR4 SNPs, Asp299Gly and Thr399Ile were genotyped and soluble(s) CD14 and sCD163 and high-sensitivity C-reactive protein, hsCRP were measured in plasma. Subclinical atherosclerosis was assessed by measuring carotid intima media thickness (cIMT). The association between CD14 C-260T SNP carriage and cIMT was assessed in a multivariable quantile regression model where a p-value of <0.05 was considered significant.

Results

We found the CD14 C-260T T-allele in 56% of the cohort and evidence of subclinical atherosclerosis in 27%. TT genotype was associated with higher sCD163 (p = 0.009) but only marginally higher sCD14 (p = 0.209) and no difference in hsCRP (p = 0.296) compared to CC/CT. In multivariable analysis, only Framingham risk score was independently associated with higher cIMT while lower sCD163 was trending towards significance. No association was found in TT-genotype carriers and cIMT measurements.

Conclusion

The CD14 C-260T SNP was associated with increased monocyte activation but not systemic inflammation or cIMT in this HIV-infected cohort with low CVD risk profile.

Differential levels of soluble inflammatory markers by human immunodeficiency virus controller status and demographics

Background. Human immunodeficiency virus (HIV)-1 elite controllers (ECs) represent an ideal population to study the effects of HIV persistence on chronic inflammation in the absence of antiretroviral therapy (ART).

Methods. Twenty inflammatory markers measured in cohorts of ECs, HIV suppressed noncontrollers, and HIV-uninfected controls were compared using rank-based tests and partial least squares discriminant analysis (PLSDA). Spearman correlations were determined among the inflammatory markers, residual viremia by the single-copy assay, and CD4⁺ T cell slope.

Results. Significant differences were seen between cohorts in 15 of the soluble inflammatory markers. Human immunodeficiency virus-1 ECs were found to have the highest levels for all of the markers with the exception of RANTES. In particular, median levels of 7 inflammatory markers (soluble CD14 [sCD14], interferon [IFN]-γ, IFN-γ-inducible protein [IP]-10, interleukin [IL]-4, IL-10, sCD40L, and granulocyte-macrophage colony-stimulating factor) were twice as high in the HIV-1 ECs compared with either of the HIV-suppressed or uninfected groups. Multivariate PLSDA analysis of inflammatory markers improved differentiation between the patient cohorts, discerning gender differences in inflammatory profile amongst individuals on suppressive ART. Soluble markers of inflammation in ECs were not associated with either levels of residual HIV-1 viremia or CD4⁺ T cell decline.

Conclusions. Despite maintaining relatively low levels of viremia, HIV-1 ECs had elevated levels of a set of key inflammatory markers. Additional studies are needed to determine whether ECs may benefit from ART and to further evaluate the observed gender differences.

Association of TLR and TREM-1 gene polymorphisms with risk of coronary artery disease in a Russian population

Atherosclerosis, manifesting itself as acute coronary syndrome, stroke, and peripheral arterial diseases, is a chronic progressive inflammatory disease which is driven by responses of both innate and adaptive immunity. Toll-like receptors (TLRs) and Triggering Receptor Expressed on Myeloid Cells-1 (TREM-1) are important effectors of the innate immune system, and polymorphisms within genes encoding them may increase risk of occurrence of various pathologies including cardiovascular disorders. Thus, we carried out a genetic association study on the sample of 702 consecutive Caucasian (Russian) patients with coronary artery disease (CAD) and 300 age-, sex-, and ethnicity-matched healthy controls. We revealed that the C/C genotype of the TLR1 rs5743551 polymorphism was significantly associated with a reduced risk of CAD according to the recessive model (OR=0.41, 95% CI=0.20-0.84, P=0.017, adjusted by age and gender). Concerning TREM-1 gene polymorphisms, we found that A/A genotype of the rs2234237 polymorphism, the G/G genotype of the rs6910730 polymorphism, the C/C genotype of the rs9471535 polymorphism, and the T/T genotype of the rs4711668 polymorphism were significantly associated with elevated CAD risk according to the recessive model (OR=5.52, 95% CI=1.17-25.98, P=0.011; OR=4.28, 95% CI=1.09-16.81, P=0.021; OR=5.55, 95% CI=1.18-26.09, P=0.011, and OR=1.66, 95% CI=1.10-2.52, P=0.014, respectively, adjusted by age and gender). Conversely, the G allele of the rs1817537 polymorphism, the T allele of the rs2234246 polymorphism, and the T allele of the rs3804277 polymorphism significantly correlated with similarly decreased risk of CAD according to the dominant model (OR=0.57, 95% CI=0.40-0.81, P=0.0013; OR=0.59, 95% CI=0.42-0.84, P=0.003, and OR=0.58, 95% CI=0.41-0.81, P=0.0014, respectively, adjusted by age and gender). We conclude that certain TLR and TREM-1 gene polymorphisms may be associated with CAD in Russian population; however, their significance as predictive and pathogenic markers of CAD should be interpreted with caution in other populations.

Soluble CD14 is independently associated with coronary calcification and extent of subclinical vascular disease in treated HIV infection

OBJECTIVE

To use multimodality imaging to explore the relationship of biomarkers of inflammation, T-cell activation and monocyte activation with coronary calcification and subclinical vascular disease in a population of HIV-infected patients on antiretroviral therapy (ART).

DESIGN

Cross-sectional.

METHODS

A panel of soluble and cellular biomarkers of inflammation and immune activation was measured in 147 HIV-infected adults on ART with HIV RNA less than 1000 copies/ml and low-density lipoprotein cholesterol (LDL-C) 130  mg/dl or less. We examined the relationship of biomarkers to coronary calcium (CAC) score and multiple ultrasound measures of subclinical vascular disease.

RESULTS

Overall, median (interquartile range, IQR) age was 46 (40-53) years; three-quarters of participants were male and two-thirds African-American. Median 10-year Framingham risk score was 6%. Participants with CAC more than 0 were older, less likely to be African-American and had higher current and lower nadir CD4 T-cell counts. Most biomarkers were similar between those with and without CAC; however, soluble CD14 was independently associated with CAC after adjustment for traditional risk factors. Among those with a CAC score of zero, T-cell activation and systemic inflammation correlated with carotid intima-media thickness and brachial hyperemic velocity, respectively. Compared with normal participants and those with CAC only, participants with increasing degrees of subclinical vascular disease had higher levels of sCD14, hs-CRP and fibrinogen (all P<0.05).

CONCLUSION

Soluble CD14 is independently associated with coronary artery calcification, and, among those with detectable calcium, predicts the extent of subclinical disease in other vascular beds. Future studies should investigate the utility of multimodality imaging to characterize vascular disease phenotypes in this population.

Toll-like receptors and damage-associated molecular patterns: novel links between inflammation and hypertension

Low-grade systemic inflammation is a common manifestation of hypertension; however, the exact mechanisms that initiate this pathophysiological response, thereby contributing to further increases in blood pressure, are not well understood. Aberrant vascular inflammation and reactivity via activation of the innate immune system may be the first step in the pathogenesis of hypertension. One of the functions of the innate immune system is to recognize and respond to danger. Danger signals can arise from not only pathogenic stimuli but also endogenous molecules released following cell injury and/or death [damage-associated molecular patterns (DAMPs)]. In the short-term, activation of the innate immune system is beneficial in the vasculature by providing cytoprotective mechanisms and facilitating tissue repair following injury or infection. However, sustained or excessive immune system activation, such as in autoimmune diseases, may be deleterious and can lead to maladaptive, irreversible changes to vascular structure and function. An initial source of DAMPs that enter the circulation to activate the innate immune system could arise from modest elevations in peripheral vascular resistance. These stimuli could subsequently lead to ischemic- or pressure-induced events aggravating further cell injury and/or death, providing more DAMPs for innate immune system activation. This review will address and critically evaluate the current literature on the role of the innate immune system in hypertension pathogenesis. The role of Toll-like receptor activation on somatic cells of the vasculature in response to the release of DAMPs and the consequences of this activation on inflammation, vasoreactivity, and vascular remodeling will be specifically discussed.

Determinants of serum concentrations of lipopolysaccharide-binding protein (LBP) in the adult population: the role of obesity

Background and Aim

Assessment of serum concentration of lipopolysaccharide (LPS)-binding protein (LBP) has been suggested as a useful biomarker to indicate activation of innate immune responses to microbial products. We investigated LBP concentrations and associations with demographics, lifestyle factors, and common metabolic abnormalities in adults. We also examined if LBP concentrations were associated with common polymorphisms in genes coding for LBP (rs2232618), CD14 (rs2569190), and TLR4 (rs4986790), the molecules responsible for the innate immune response to LPS, or serum levels of soluble CD14 (sCD14) and proinflammatory cytokines.

Methods

Serum LBP was measured with a commercial immunoassay in a random sample of the adult population (n = 420, 45% males, age 18–92 years) from a single municipality.

Results

Serum LBP concentrations increased with age (P<0.001) and were higher in individuals who were overweight or obese than in normal-weight individuals (P<0.001). Similarly, LBP concentrations were higher in individuals with metabolic syndrome than in individuals without it (P<0.001). Among metabolic syndrome components, LBP concentrations were independently associated with abdominal obesity (P = 0.002) and low concentrations of HDL-cholesterol (P<0.001). Serum LBP concentrations tended to be independently associated with smoking (P = 0.05), but not with alcohol consumption. Likewise, there was not significant association between LBP concentrations and gene polymorphisms. Concentrations of LBP significantly correlated with serum levels of proinflammatory cytokines (IL-6 and IL-8), sCD14, and with liver enzymes.

Conclusions

Serum LBP concentrations increased with age. Overweight, obesity, and having metabolic syndrome (particularly, low HDL cholesterol levels) were associated with higher LBP concentrations. These findings are consistent with microbial exposure playing a role in these inflammatory, metabolic abnormalities.

The association between CD14 gene C-260T polymorphism and coronary heart disease risk: a meta-analysis

Monocyte differentiation antigen CD14 is considered an important cell-activating mediator of inflammatory responses that may result in atherosclerosis, coronary heart disease (CHD), thrombus formation, and myocardial infarction (MI). A common C-260T polymorphism in the promoter of the CD14 gene, the trans-membrane receptor of lipopolysaccharides, has been inconsistently associated with CHD. To investigate this inconsistency, we performed a meta-analysis of 28 studies involving a total of 13,335 CHD cases and 7,979 controls for C-260T of the CD14 gene to evaluate the effect of CD14 on genetic susceptibility for CHD. An overall random effects odds ratio of 1.24 (95 % CI: 1.12-1.36, P < 10(-5)) was found for T allele. Significant results were also observed using dominant (OR = 1.34, 95 % CI: 1.17-1.54, P < 10(-4)) or recessive genetic model (OR = 1.25, 95 % CI: 1.10-1.41, P = 0.0004). There was strong evidence of heterogeneity (P < 10(-5)), which largely disappeared after stratification by ethnicity. After stratified by ethnicity, significant results were found in East Asians; whereas no significant associations were found among Caucasians and other ethnic populations in all genetic models. In the stratified analysis according to sample size, CHD endpoints, and HWE status, significantly increased risks for the polymorphism were found in all genetic models. In conclusion, our results indicate that the CD14 C-260T polymorphism is a risk factor of CHD, especially in East Asians. However, additional very large-scale studies are warranted to confirm our results.

Soluble CD14: genomewide association analysis and relationship to cardiovascular risk and mortality in older adults

OBJECTIVE

CD14 is a glycosylphosphotidylinositol-anchored membrane glycoprotein expressed on neutrophils and monocytes/macrophages that also circulates as a soluble form (sCD14). Despite the well-recognized role of CD14 in inflammation, relatively little is known about the genetic determinants of sCD14 or the relationship of sCD14 to vascular- and aging-related phenotypes.

METHODS AND RESULTS

We measured baseline levels of sCD14 in >5000 European-American and black adults aged 65 years and older from the Cardiovascular Health Study, who were well characterized at baseline for atherosclerotic risk factors and subclinical cardiovascular disease, and who have been followed for clinical cardiovascular disease and mortality outcomes up to 20 years. At baseline, sCD14 generally showed strong positive correlations with traditional cardio-metabolic risk factors and with subclinical measures of vascular disease such as carotid wall thickness and ankle-brachial index (independently of traditional cardiovascular disease risk factors), and was also inversely correlated with body mass index. In genomewide association analyses of sCD14, we (1) confirmed the importance of the CD14 locus on chromosome 5q21 in European-American; (2) identified a novel African ancestry-specific allele of CD14 associated with lower sCD14 in blacks; and (3) identified a putative novel association in European-American of a nonsynonymous variant of PIGC, which encodes an enzyme required for the first step in glycosylphosphotidylinositol anchor biosynthesis. Finally, we show that, like other acute phase inflammatory biomarkers, sCD14 predicts incident cardiovascular disease, and strongly and independently predicts all-cause mortality in older adults.

CONCLUSIONS

CD14 independently predicts risk mortality in older adults.

Biomarkers of microbial translocation and macrophage activation: association with progression of subclinical atherosclerosis in HIV-1 infection

BACKGROUND

The relationships between soluble CD14 (sCD14), endotoxin (lipopolysaccharide [LPS]), and progression of atherosclerosis have not been defined in human immunodeficiency virus (HIV) infection.

METHODS

We retrospectively assessed serum sCD14 and LPS levels of 91 subjects in a prospective 3-year study of carotid artery intima-media thickness (CIMT) (AIDS Clinical Trials Group [ACTG] 5078), where subjects were enrolled as risk factor-controlled triads of HIV-uninfected (n = 36) and HIV-infected individuals with (n = 29) or without (n = 26) protease inhibitor (PI)-based therapy for ≥2 years. The primary end point was the yearly rate of change of CIMT (ΔCIMT).

RESULTS

In multivariate analysis of the HIV-infected subjects, each 1 µg/mL above the mean of baseline serum sCD14 corresponded to an additional 1.52 µm/y (95% confidence interval, .07-2.98; P = .04) in the ΔCIMT. Every 100 pg/mL above the mean of baseline serum LPS corresponded to an additional 0.49 µm/y (95% confidence interval, .18-.81; P = .003) in the ΔCIMT. However, in univariate analysis in the HIV-uninfected group sCD14 (P = .33) and LPS (P = .27) levels were not associated with higher ΔCIMT. HIV infection and PI therapy were not associated with baseline serum LPS and sCD14 levels (P > .1).

CONCLUSIONS

Our data are among the first to suggest that serum biomarkers of microbial translocation (LPS) and macrophage activation (sCD14) predict subclinical atherosclerosis progression in HIV-infected persons.

Lack of association between TLR4 Asp299Gly polymorphism and atherosclerosis: evidence from meta-analysis

INTRODUCTION

Toll like receptor 4 (TLR4) expression was found to increase markedly in human atherosclerotic lesions, notably on macrophages and endothelial cells. TLR4 Asp299Gly polymorphism was associated with a blunted receptor activity and a subsequently diminished inflammatory response, and may subsequently reduce atherosclerosis (AS) risk. However, the results of molecular epidemiological studies remained inconsistent.

MATERIALS AND METHODS

The PubMed, CNKI databases were searched for all articles available. The OR corresponding to the 95% confidence interval (95% CI) was used to assess the association between TLR4 Asp299Gly polymorphism and risk of AS.

RESULTS

15 case-control studies with 9,989 cases and 6,746 controls were available for this analysis. For control subjects, G allele frequency of TLR4 Asp299Gly polymorphism was ranging from 0.045 to 0.085. The G allele and the AG/GG genotypes were not associated with significantly risk of AS (OR=1.02, 95% CI=0.83 - 1.26 for G versus A and OR=0.96, 95% CI=0.80 - 1.15 for AG/GG versus AA, respectively) by random effects model.

CONCLUSION

These findings indicated that TLR4 Asp299Gly polymorphism may not play a role in AS development.

Association studies of Toll-like receptor gene polymorphisms with allograft survival in renal transplant recipients of North India

Organ transplantation itself inevitably activates the innate immune system by Toll-like receptors (TLRs), potentially leading to allograft rejection and graft failure. We evaluated the possible association of TLR2, TLR3, and TLR9 polymorphisms of donor-recipient pairs and acute rejection in renal transplant patients of North India. TLR2 (-196 to -174 del), TLR3 (c.1377C/T; rs 3775290), and TLR9 (+2848 G/A; rs 352140) were genotyped using DNA samples from 200 donor-recipient pairs of live donor kidney transplantation by applying Restriction Fragment Length Polymorphism (RFLP) methodology. The variant allele frequency of TLR2 (-196 to -174 del) was significantly different between recipients and donors (7.5% vs. 5.0%; p = 0.049; OR = 3.9; 95% CI = 1.01-15.32). However, no significant association for allograft rejection was observed in transplant recipients for TLR3 and TLR9. Interestingly, a low prevalence of AA genotype of TLR9 + 2848 G>A was observed in rejecters when compared with non-rejecters, demonstrating protective association with allograft rejection (OR = 0.30, 95% CI = 0.12-0.88, p = 0.028). An allele in patients was also observed to be associated with higher rejection-free survival (log-rank = 0.044). These TLR gene polymorphisms, upon further evaluation, may be helpful in elucidation of immunobiological mechanisms associated with renal graft rejection.

Macrophage migration inhibitory factor, Toll-like receptor 4, and CD14 polymorphisms with altered expression levels in patients with ulcerative colitis

Ulcerative colitis is a multifactorial disease in which genetic factors play a major role. Functional mutations in the genes related to innate immune response exacerbate mucosal damage coupled with persistent inflammation. The cytokine macrophage migration inhibitory factor (MIF), CD14, and Toll-like receptor 4 (TLR4) are the central players with clearly defined roles in inflammation. The aim of this study was to investigate the association between MIF-173G > C, CD14-159C > T, and TLR4-299A > G polymorphisms and mononuclear cell expression in patients with ulcerative colitis (UC). Genotyping of MIF-173G > C, CD14-159C > T, and TLR4-299A > G polymorphisms was performed by amplification refractory mutation system-polymerase chain reaction and allele-specific amplification in 139 and 176 patients with UC and controls, respectively. Simultaneously, the expression levels of intracellular MIF, mCD14, and mTLR4 were determined in mononuclear cells using a flow cytometer. Polymorphisms in CD14-159C > T and TLR4-299A > G significantly affected mCD14 and mTLR4 expression levels and also increased susceptibility to UC. Although intracellular MIF expression levels differed among patient and control groups, the polymorphism in MIF 173G > C was not observed to be associated with a risk of UC.

TLR4 gene polymorphisms: evidence for protection against type 2 diabetes but not for diabetes-associated ischaemic heart disease

OBJECTIVE

Several factors either predisposing or protecting from the onset of diabetes mellitus type 2 (DM2) have been proposed. Two specific polymorphisms of toll-like receptor 4 (TLR4; Asp299Gly and Thr399Ile) have recently been identified either as candidate protector genes against DM2 and associated neuropathy or risk alleles for the manifestation of diabetic retinopathy. The impact of these alleles on the risk for ischaemic heart disease (IHD) is controversial while their role in diabetes-associated IHD has never been studied.

DESIGN AND METHODS

In order to clarify the potential impact of TLR4 polymorphisms on the predisposition for DM2 as well as on diabetes-related IHD vulnerability, the distribution of the mutant TLR4 Asp299Gly and Thr399Ile alleles in 286 DM2 patients and 413 non-DM2 controls with or without IHD, was examined.

RESULTS

Mutant alleles were predominantly detected in 79/413 non-diabetic individuals versus 15/286 DM2 patients (P<0.0001). The rates of positivity for mutant alleles were similar among diabetic patients with or without IHD (7/142 vs 8/144, P>0.1), whereas they proved different among non-diabetic individuals with or without IHD (39/145 vs 40/268, P=0.004). Following multivariate analysis, the difference between diabetic and non-diabetic subjects, with regard to TLR4 mutations alone, remained significant (P=0.04).

CONCLUSIONS

Mutant TLR4 alleles confer protection against DM2. However, their presence does not seem to play any role, protective or aggravating, in the manifestation of IHD either in diabetic or in non-diabetic individuals.

Toll-like receptors and myocardial ischemia/reperfusion, inflammation, and injury

Cardiac ischemia/reperfusion (I/R) injury occurs in several important clinical contexts including percutaneous coronary interventions for acute myocardial ischemia, cardiac surgery in the setting of cardiopulmonary bypass, and cardiac transplantation. While the pathogenesis of I/R injury in these settings is multifactorial, it is clear that activation of the innate immune system and the resultant inflammatory response are important components of I/R injury. Toll-like receptor 4 (TLR4), originally identified as the sensor for bacterial lipopolysaccharide (LPS), has also been shown to serve as a sensor for endogenous molecules released from damaged or ischemic tissues. Accordingly, recent findings have demonstrated that TLR4 not only plays a central role as a mediator of cardiac dysfunction in sepsis, but also serves as a key mediator of myocardial injury and inflammation in the setting of I/R. Furthermore, TLR4 may play a role in the development of atherosclerotic lesions. Other studies have implicated TLR4 in the adverse remodeling that may occur after ischemic myocardial injury. This emerging body of literature, which is reviewed here, has provided new insight into the early molecular events that mediate myocardial injury and dysfunction in the setting of I/R injury.

The emerging role of innate immunity in the heart and vascular system: for whom the cell tolls

Recent studies suggest that the heart possesses an innate immune system that is intended to delimit tissue injury, as well as orchestrate homoeostatic responses, within the heart. The extant literature suggests that this intrinsic stress response system is mediated, at least in part, by a family of pattern recognition receptors, most notably the Toll-like receptors. Although the innate immune system provides a short-term adaptive response to tissue injury, the beneficial effects of this phylogenetically ancient system may be lost if innate immune signaling becomes sustained and/or excessive; in which case, the salutary effects of activation of these pathways are contravened by the known deleterious effects of inflammatory signaling. Herein, the biology of innate immune signaling in the heart is reviewed, as well as the literature suggesting that the innate immune system is involved in the pathogenesis of atherosclerosis, acute coronary syndromes, stroke, viral myocarditis, sepsis, ischemia/reperfusion injury, and heart failure. The review concludes by discussing new therapies that are being developed to modulate the innate immune system.

Role of toll-like receptors in cardiovascular diseases

The discovery and characterization of the TLR (Toll-like receptor) family has led to a better understanding of the innate immune system. The strategy of innate immune recognition is based on the detection of constitutive and conserved products of micro-organisms. However, host molecules that are released during injury can also activate TLRs. Engagement of TLRs by microbial or host-derived molecules induces the expression of pro-inflammatory cytokines, which may have both beneficial and detrimental effects on the host. In addition to being expressed in immune cells, TLRs are expressed in other tissues such as those of the cardiovascular system. In the present review, the role of TLRs in septic cardiomyopathy, viral myocarditis, atherosclerosis, ischaemia/reperfusion injury and cardiac remodelling after myocardial infarction are outlined, with attention paid to genetically modified murine models. Although much has been learned about stress-induced TLR activation in the tissues of the cardiovascular system, the role of individual TLRs in initiating and integrating homoeostatic responses within the heart remains to be defined. Accumulating evidence indicates that TLRs may play an important role in the pathogenesis of atherosclerosis, viral myocarditis, dilated cardiomyopathy, cardiac allograft rejection and sepsis-induced left ventricular dysfunction. Moreover, heart failure of diverse aetiology is also now recognized to have an important immune component, with TLR signalling influencing the process of cardiac remodelling and prognosis. In the present review, we outline the biology of TLRs as well as the current experimental and clinical evidence for the role of TLRs in cardiovascular diseases.

Lipopolysaccharide, CD14 and Toll-like receptors: an emerging link between innate immunity and atherosclerotic disease

Atherosclerosis and its clinical complications are now understood to be an inflammatory syndrome in which an ongoing systemic inflammatory response is combined with the accumulation of immune cells in the atherosclerotic plaque. Both arms of the immune system, innate and adaptive, have been implicated in contributing to essentially all stages of atherosclerosis, from initiation to progression and, ultimately, atherothrombotic complications. Innate immunity is the first line of defense against invading microorganisms. The recognition units of the innate immune system are designed to respond to molecular patterns shared by a variety of infectious microorganisms, such as bacterial lipopolysaccharide. Numerous basic and clinical studies have provided evidence that responsiveness to lipopolysaccharide may be correlated to the risk of atherosclerotic disease. The molecular basis of this connection appears to lie in Toll-like receptors that are expressed on cells of the innate immune system, bind to lipopolysaccharide, and thus determine the strength of antibacterial immune responses in the host. Variations in the function of Toll-like receptors and their signaling pathways are now suspected to play a critical role in determining the risk of atherosclerosis. This review summarizes recent research advances exploring the role of innate immunity, particularly lipopolysaccharide, CD14 and Toll-like receptors, in the initiation and development of atherosclerotic disease.

Toll-like receptors and atherosclerosis: oxidized LDL as an endogenous Toll-like receptor ligand

The oxidation hypothesis of atherosclerosis suggests that oxidative modification of low-density lipoprotein (LDL) is a prerequisite for LDL atherogenicity. Recent studies demonstrate that upon oxidative modification, LDL becomes enriched with pathogen-associated molecular patterns recognized by natural (inborn) antibodies and innate immune receptors. This review focuses on recent findings showing that Toll-like receptors (TLRs)--which sense microbial pathogens and initiate immediate inflammatory responses--are potentially involved in the pathogenesis of atherosclerosis. In addition to the data that bacterial agonists of TLR4 and TLR2 accelerate atherosclerosis, new evidence suggests that minimally oxidized LDL and specific oxidized phospholipids signal via TLRs to induce cytoskeletal changes and inflammatory cytokine secretion by macrophages and endothelial cells. Identifying the signaling mechanisms by which oxidized LDL induces chronic inflammation in atherosclerotic lesions may lead to novel therapeutic targets for the treatment of atherosclerotic cardiovascular disease.

Single-nucleotide polymorphisms in genes encoding toll-like receptor -2, -3, -4, and -9 in case-control study with breast cancer

BACKGROUND

Genetic susceptibility to cancer is multifactorial, and it is known that impairment of the immune system could contribute to risk for getting cancer.

AIM OF THE STUDY

Single-nucleotide polymorphisms (SNPs) of Toll-like receptor (TLR) 2, TLR3, TLR4, and TLR9 genes, which are important for innate immunity, were analyzed for the association with breast cancer.

METHODS

The SNPs comprised TLR2 (c.597T>C), TLR2 (c.1350T>C), TLR3 (c.1377C>T), TLR4 (c.896A>G), and TLR9 (c.1635A>G). The allelic and genotypic frequencies of these TLR SNPs were compared between patients (n = 130) and controls (n = 101) in a case-control study from Croatia.

RESULTS

TLR SNPs were not significantly different. From the population genetics viewpoint, we found that a hypomorphic variant of TLR4 (p.Asp299Gly) allele has no specific allelic frequency (8.4%) in the Croatian population (n = 496) compared to other Caucasians (6.5-10%).

CONCLUSION

These results suggest that polymorphisms in tested TLR genes are not likely to be associated with increased risk for developing breast cancer.

Impact of polymorphisms of TLR4/CD14 and TLR3 on acute rejection in kidney transplantation

BACKGROUND

Organ transplantation itself inevitably activates the innate immune system by toll-like receptors (TLRs), potentially leading to allograft rejection and graft failure. We evaluated the possible association between the TLR4/CD14 and TLR3 polymorphisms of donor-recipient pairs, and acute rejection after living donor kidney transplantation.

METHODS

TLR4 -1607T/C (rs10759932), -2026A/G (rs1927914); CD14 -159C/T (rs2569190); and TLR3 rs3775290, rs3775291, and rs3775296 were genotyped using DNA samples from 216 donor-recipient pairs of adult living donor kidney transplantation between January 1996 and July 2006. Dual luciferase reporter assay was performed to determine the functional significance of promoter single-nucleotide polymorphisms (SNPs) of TLR4.

RESULTS

Acute rejection occurred in 42 recipients (19.4%) of 216 adult transplant patients within 1 year. The genotype distributions of both recipient and donor TLR4 rs10759932 differed significantly between the control (no rejection) and acute rejection groups. For recipient rs10759932, the adjusted odds ratio for the TC+CC over TT genotype was 0.25 (95% confidence interval, 0.11-0.57; P =0.001). When the rs10759932 CC genotype was present in the recipient or donor, no episode of acute rejection occurred (Fisher's exact test, P =0.023). The presence of the rs10759932 C allele was associated with higher rejection-free survival rates (log-rank test, P =0.0053). However, there was no difference in transcriptional activity between wild-type and variant promoters of TLR4. In contrast to TLR4, SNPs of TLR3 or CD14 had no influence on acute rejection.

CONCLUSION

These findings suggest the importance of TLR4 in the pathogenesis of acute rejection in kidney transplantation.

CD14 C-260T gene polymorphism and ischemic heart disease susceptibility: a HuGE review and meta-analysis

The CD14 gene C-260T polymorphism has been reported to be associated with ischemic heart disease, but results were conflicting. To evaluate the role of the CD14 C-260T polymorphism in ischemic heart disease, we performed meta-analyses of all available data. Comprehensive searches for studies on the association between the genotypes (CC, CT, TT) distributions and ischemic heart disease risk were performed. Patients with acute coronary syndrome, prior myocardial infarction, stable angina pectoris, or angiographic coronary artery stenosis were included. Potential sources of heterogeneity were explored by meta-regression. Analyses were performed under European, East Asian, and Indian studies, respectively. Data were available for 19 studies involving 11,813 cases and 6,196 controls. The summary odds ratio under the recessive model was 1.53 (95% confidence interval: 1.20-1.96) for East Asian studies published in English language journals on overall ischemic heart disease. Pooled odds ratios under the codominant model were about 1.81 (95% confidence interval: 1.36-2.40) and 1.70 (95% confidence interval: 1.26-2.29) for Chinese studies on overall ischemic heart disease and other ischemic heart disease (angina pectoris and angiographic coronary artery stenosis), respectively. No significant association was found in a European population, an Indian population, or the vulnerable plaque ischemic heart disease (acute coronary syndrome and prior myocardial infarction) subgroup of an East Asian population. It is probable that T allele and TT genotype are associated with ischemic heart disease in the East Asian population but not in the European or Indian populations. Further studies are warranted to assess these associations in greater details, especially in East Asian and Indian populations.

TLR4 polymorphisms and ageing: implications for the pathophysiology of age-related diseases

INTRODUCTION

Innate immunity provides a first line of host defense against infection by recognizing and killing microbes while simultaneously activating an instructive immune response. Toll-like receptors (TLRs) are principal mediators of rapid microbial recognition and function mainly by detection of pathogen-associated molecular patterns that do not exist in the host. Recognition of their ligands leads to a series of signaling events resulting in acute host responses, involved in killing pathogens.

DISCUSSION

We describe the involvement of TLR4 polymorphisms in ageing, and in particular in age-related diseases, suggesting the crucial role of molecules of innate immunity in pathophysiology of these diseases. Hence, we observed that pro-inflammatory alleles may be related to unsuccessful ageing, such as Alzheimer's disease, prostate cancer, and atherosclerosis; in contrast, the control of inflammation by anti-inflammatory alleles may result in increased longevity and successful ageing. Finally, a possible therapeutic approach to delay age-related diseases is outlined.

Toll-like receptors: new therapeutic targets for the treatment of atherosclerosis, acute coronary syndromes, and myocardial failure

The toll-like receptors (TLRs) are a class of transmembrane molecules that have important functions in both innate and acquired immunity. As part of the body's normal immune defense against microbial pathogens, stimulation of these receptors will trigger the inflammatory response cascade and the release of cytokines. Activation of these receptors also plays a role in a variety of systemic inflammatory diseases such as asthma, sepsis, atherosclerosis, acute coronary artery disease, and left ventricular remodeling. Pharmacologic approaches to modify the actions of TLRs are now under consideration as potential treatments for inflammatory systemic diseases that include atherosclerosis. At the same time, it is essential to characterize the benefits and risks of modifying such an important part of the body's innate immune system.

Risk factor correlates of platelet and leukocyte markers assessed by flow cytometry in a population-based sample

BACKGROUND

Platelet and leukocyte products are involved in atherothrombosis. However, the determinants of platelet and leukocyte markers assessed by flow cytometry have not been documented in a population-based sample.

METHODS AND RESULTS

We performed flow cytometry on blood from participants (n=1894) in the Atherosclerosis Risk in Communities (ARIC) Carotid MRI Study. Cellular aggregates and multiple platelet and leukocyte markers, such as myeloperoxidase in granulocytes and toll-like receptor-4, CD14, and CD45 in monocytes, were quantified. Their cross-sectional associations with demographic and risk factors were assessed using multiple linear regression. Mean values of most cellular markers and aggregates were considerably higher in blacks than whites (p<0.01). There were some differences in cellular markers between men and women, but little association with age. LDL-cholesterol was associated positively with several markers (toll-like receptor-4 and myeloperoxidase in granulocytes and CD162 in lymphocytes). Cholesterol-lowering therapy tended to show opposite associations. Smokers had much higher granulocyte myeloperoxidase than nonsmokers. However, most other correlations between risk factors and cellular markers were nonsignificant.

CONCLUSIONS

Race/ethnicity, sex, and to a lesser degree LDL-cholesterol and cholesterol-lowering therapy, but few other risk factors, were correlated with markers of cellular activation in this population-based study.

Gene-environment interactions between CD14 C-260T and endotoxin exposure on Foxp3+ and Foxp3- CD4+ lymphocyte numbers and total serum IgE levels in early childhood

BACKGROUND

Innate immune system stimuli, such as endotoxin, seem to affect allergy risk. Previously, we described gene-environment interactions between the endotoxin receptor polymorphism C-260T of the CD14 gene and endotoxin exposure on total serum IgE level; however, the mechanism of this interaction is not known.

OBJECTIVE

To examine whether this gene-environment interaction affects early CD4(+)Foxp3(-) or CD4(+)Foxp3(+) lymphocyte numbers.

METHODS

Participating children were part of a birth cohort in the Detroit metropolitan area. Participants were genotyped for the CD14 C-260T polymorphism. Endotoxin exposure was estimated from dust measured in the home when children were 6 months old. Intracellular Foxp3 protein expression, a regulatory T-cell marker, was used to characterize CD4(+) lymphocytes in blood samples collected at the age of 12 months; total serum IgE level was also measured at this time. Because race/ethnicity may confound or modify genetic associations, all analyses were stratified by race/ethnicity.

RESULTS

We observed a significant gene-environment interaction between CD14 C-260T genotype and endotoxin exposure on CD4(+) lymphocyte numbers, particularly CD4(+)Foxp3(-) lymphocytes. Stratified analyses suggest effect modification by race/ ethnicity on CD4(+)Foxp3(+) lymphocyte numbers, with a significant interaction in African American children but not in white children. The interaction between CD14 C-260T genotype and endotoxin exposure on total IgE levels was opposite that observed for CD4(+) lymphocyte numbers, suggesting reciprocal relationships.

CONCLUSIONS

A gene-environment interaction between endotoxin and CD14 C-260T genotype on IgE levels may be the result of an upstream, opposing effect on CD4(+)Foxp3(+) and CD4(+)Foxp3(-) lymphocyte numbers. Race/ethnicity may affect which of these cell populations is affected by this gene-environment interaction.

Review: variability of host-pathogen interaction

The course of every infection is different. The same pathogen can lead to subclinical, mild, severe or lethal infections in individuals. But is this just chance or determined by individual differences--on the side of the host as well as on the side of the pathogen? If so, we might need to consider these variations for treatment decisions. Indeed, we now understand that genetic polymorphisms and health status represent inborn and acquired risk factors. Similarly, pathogens impress with an increasing number of already identified virulence factors and host response modifiers. The emerging, more complex, view of the factors determining course and outcome of infections promises to enable more tailored and thus, hopefully, more effective treatment decisions.

Toll-like receptor polymorphisms and susceptibility to human disease

Although several lines of evidence suggest that variation in human inflammation is genetically controlled, the genes which regulate these responses are largely unknown. TLRs (Toll-like receptors) mediate recognition of microbes, regulate activation of the innate immune response and influence the formation of adaptive immunity. Cellular and molecular studies over the past several years have identified a number of common TLR polymorphisms that modify the cellular immune response and production of cytokines in vitro. In addition, human genetic studies suggest that some of these polymorphisms are associated with susceptibility to a spectrum of diseases. In this review, we summarize studies of common TLR polymorphisms and how this work is beginning to illuminate the influence of human variation on inflammation and disease susceptibility.