Effect of the Toll-like receptor 4 (TLR-4) variants on intima-media thickness and monocyte-derived macrophage response to LPS

Association of Intima-Media Thickness Measured at the Common Carotid Artery With Incident Carotid Plaque: Individual Participant Data Meta-Analysis of 20 Prospective Studies

Background The association between common carotid artery intima-media thickness (CCA-IMT) and incident carotid plaque has not been characterized fully. We therefore aimed to precisely quantify the relationship between CCA-IMT and carotid plaque development. Methods and Results We undertook an individual participant data meta-analysis of 20 prospective studies from the Proof-ATHERO (Prospective Studies of Atherosclerosis) consortium that recorded baseline CCA-IMT and incident carotid plaque involving 21 494 individuals without a history of cardiovascular disease and without preexisting carotid plaque at baseline. Mean baseline age was 56 years (SD, 9 years), 55% were women, and mean baseline CCA-IMT was 0.71 mm (SD, 0.17 mm). Over a median follow-up of 5.9 years (5th-95th percentile, 1.9-19.0 years), 8278 individuals developed first-ever carotid plaque. We combined study-specific odds ratios (ORs) for incident carotid plaque using random-effects meta-analysis. Baseline CCA-IMT was approximately log-linearly associated with the odds of developing carotid plaque. The age-, sex-, and trial arm-adjusted OR for carotid plaque per SD higher baseline CCA-IMT was 1.40 (95% CI, 1.31-1.50; I²=63.9%). The corresponding OR that was further adjusted for ethnicity, smoking, diabetes, body mass index, systolic blood pressure, low- and high-density lipoprotein cholesterol, and lipid-lowering and antihypertensive medication was 1.34 (95% CI, 1.24-1.45; I²=59.4%; 14 studies; 16 297 participants; 6381 incident plaques). We observed no significant effect modification across clinically relevant subgroups. Sensitivity analysis restricted to studies defining plaque as focal thickening yielded a comparable OR (1.38 [95% CI, 1.29-1.47]; I²=57.1%; 14 studies; 17 352 participants; 6991 incident plaques). Conclusions Our large-scale individual participant data meta-analysis demonstrated that CCA-IMT is associated with the long-term risk of developing first-ever carotid plaque, independent of traditional cardiovascular risk factors.

Investigating the multi-target pharmacological mechanism of danhong injection acting on unstable angina by combined network pharmacology and molecular docking

Background

Danhong injection (DHI), which is one of the most well-known Traditional Chinese Medicine (TCM) injections, widely used to treat unstable angina (UA). However, its underlying pharmacological mechanisms need to be further clarified.

Methods

In the present study, network pharmacology was adopted. Firstly, the relative compounds were obtained by a wide-scaled literatures-mining and potential targets of these compounds by target fishing were collected. Then, we built the UA target database by DisGeNET, DigSee, TTD, OMIM. Based on data, protein-protein interaction (PPI) analysis, GO and KEGG pathway enrichment analysis were performed and screen the hub targets by topology. Furthermore, evaluation of the binding potential of key targets and compounds through molecular docking.

Results

The results showed that 12 ingredients of DHI and 27 putative known therapeutic targets were picked out. By systematic analysis, identified 4 hub targets (TNF, TLR4, NFKB1 and SERPINE1) mainly involved in the complex treating effects associated with coagulation and hemostasis, cell membrane region, platelet alpha granule, NF-kappa B signaling pathway and TNF signaling pathway.

Conclusion

The results of this study preliminarily explained the potential targets and signaling pathways of DHI in the treatment of UA, which may help to laid a good foundation for experimental research and further clinical application.

Multilevel Models to Estimate Carotid Intima-Media Thickness Curves for Individual Cardiovascular Risk Evaluation

Background and Purpose- The value of carotid intima-media thickness (cIMT)-a marker of subclinical atherosclerosis-in defining the cardiovascular risk is still debated. The aim of this study was to estimate standard cIMT progression, adjusting values over time for the main cardiovascular risk factors, in a sample of low-to-moderate cardiovascular risk subjects, to identify normative cIMT progression values. Methods- From the progression of lesions in the intima of the carotid cohort, we selected subjects who underwent 4 planned serial clinical evaluations and ultrasound cIMT determinations, on average every 4 years. Subject taking glucose-lowering therapies in secondary cardiovascular prevention or with cardiovascular risk score >5 were excluded from the analysis. The growth of cIMT across the study period (12 years) was assessed by use of individual growth curve modeling within multilevel models. Results- A total of 1175 (36% men; mean age, 53±11 years at baseline) participants at low/intermediate cardiovascular risk have been included in this analysis. A significant and marked slope of the mean and maximum cIMT growth curves (β=0.009 and β=0.012, respectively) was observed, confirming that it is a function of age. A stratified analysis by decades of age highlighted a nonlinear cIMT progression over time. In addition, different patterns of cIMT development between sex were observed. Finally, different slopes in mean and maximum cIMT curves, with a significant spread since the fifth decade, were observed in the cIMT growth curve models of subjects developing multifocal carotid atherosclerosis compared with the rest of the population. Conclusions- These findings proved that the rate of change in cIMT over time is a sign of the development of atherosclerosis, which cannot be a priori assumed linear. These data, therefore, support the clinical relevance of these growth curve models for cIMT progression to be considered as useful tool to identify subjects with faster atherosclerosis progression and thus at increased cardiovascular risk.

Role of toll-like receptor 4 Asp299Gly polymorphism in the development of cardiovascular diseases in HIV-infected patients

OBJECTIVE

Cardiovascular diseases (CVDs) are one of the main causes of morbimortality in HIV-infected patients on suppressive antiretroviral therapy. The objective of this work was to evaluate the role of single nucleotide polymorphisms (SNPs) in lipopolysaccharide (LPS) Toll-like receptor 4 (TLR4) and CVDs occurrence in HIV-infected patients. Additionally, the functional consequences of carrying these SNPs were analyzed.

METHODS

The association of TLR4 SNPs, Asp299Gly/Thr399Ile with CVDs occurrence was analyzed using multivariate logistic regression models. Clinical, immunological, and traditional cardiovascular risk factors were used as covariates. The monocyte phenotype and response were assessed by multiparametric flow cytometry comparing carriers with noncarriers of this SNP.

RESULTS

Asp299Gly SNP, assayed in 253 HIV-infected patients, was independently associated with the occurrence of CVDs after adjusting for CD4+ T-cell nadir, HCV-coinfection, bacterial pneumonia, diabetes mellitus, and traditional cardiovascular risk factors [odds ratio (confidence interval 95%) = 3.672 (1.061-12.712), P = 0.04). Carriers of Asp299Gly SNP showed higher percentage of patrolling and intermediate monocytes producing a proinflammatory combination of cytokines compared with noncarriers (P = 0.037 and P = 0.046, respectively). Intermediate monocyte subset levels correlated with soluble interleukin-6 levels only in carriers (r = 0.89; P = 0.01).

CONCLUSION

TLR4 Asp299Gly polymorphism is independently associated with the occurrence of CVDs in HIV-infected patients. The proinflammatory profile associated to this variant could be involved in the development of atherosclerotic pathologies.

Disease trends over time and CD4+CCR5+ T-cells expansion predict carotid atherosclerosis development in patients with systemic lupus erythematosus

BACKGROUND AND AIM

Patients with Systemic Lupus Erythematosus (SLE) present increased cardiovascular mortality compared to the general population. Few studies have assessed the long-term development and progression of carotid atherosclerotic plaque in SLE patients. Our aim was to investigate the association of clinical and laboratory markers of disease activity and classical cardiovascular risk factors (CVRF) with carotid atherosclerosis development in SLE patients in a prospective 5-year study.

METHODS AND RESULTS

Clinical history and information on principal CVRFs were collected at baseline and after 5 years in 40 SLE patients (36 women, mean age 42 ± 9 years; 14.4 ± 7 years of mean disease duration) and 50 age-matched controls. Carotid Doppler ultrasonography was employed to quantify the atherosclerotic burden at baseline and at follow up. Clinimetrics were applied to assess SLE activity over time (SLEDAI). The association between basal circulating T cell subsets (including CD4⁺CCR5⁺; CD4⁺CXCR3⁺; CD4⁺HLADR⁺; CD4⁺CD45RA⁺RO^-, CD4⁺CD45RO⁺RA^- and their subsets) and atherosclerosis development was evaluated. During the 5-year follow up, 32% of SLE patients, developed carotid atherosclerosis compared to 4% of controls. Furthermore, considering SLEDAI changes over time, patients within the highest tertile were those with increased incidence of carotid atherosclerosis independently of CVRF. In addition, increased levels of CD4⁺CCR5⁺ T cells were independently associated with the development of carotid atherosclerosis in SLE patients.

CONCLUSION

Serial clinical evaluations over time, rather than a single point estimation of disease activity or CVRF burden, are required to define the risk of carotid atherosclerosis development in SLE patients. Specific T cell subsets are associated with long-term atherosclerotic progression and may further be of help in predicting vascular disease progression.

Differences in expression of genes in the MyD88 and TRIF signalling pathways and methylation of TLR4 and TRIF in Tibetan chickens and DaHeng S03 chickens infected with Salmonella enterica serovar enteritidis

Salmonella enterica serovar (S. enteritidis) is a pathogenic bacterium that can cause symptoms of food poisoning, leading to death of poultry, resulting in serious economic losses. The MyD88 and TRIF signalling pathways play important roles in activating innate and adaptive immunity in chickens infected with S. enteritidis. The objective of the present study was to characterize in vivo mRNA expressions, protein levels and methylation levels of genes in the above two pathways in both Tibetan chickens and DaHeng S03 chickens infected with S. enteritidis. MyD88-dependent and TRIF-dependent signalling pathway were activated by infection, and the MyD88 signalling pathway induced cytokines LITAF and IL-8 played important roles in fighting against the S. enteritidis infection in vivo. The TLR4 methylation might alter expression of genes involved in the MyD88 signalling pathway, and thus different breeds of chickens might show differences in susceptibility to the S. enteritidis. The increased expression of INF β was activated by S. enteritidis, but its expressions were different in levels of mRNA and protein in Tibetan chickens and DaHeng chickens, suggesting its functions on the resistance to S. enteritidis infection in chickens. This study contributes to the understanding of two pathways activated in response to S. enteritidis infection, and gives indications on the mechanisms underlying resistance of Tibetan chickens and DaHeng chickens to S. enteritidis.

Association of TLR and TREM-1 gene polymorphisms with atherosclerosis severity in a Russian population

Local vascular immune response is primarily initiated via Toll-like receptors (TLRs) and triggering receptor expressed on myeloid cells-1 (TREM-1). We previously showed that certain TLR and TREM-1 gene polymorphisms are associated with coronary artery disease (CAD). Therefore, we hypothesized that these gene polymorphisms are associated with atherosclerosis severity. This study included 292 consecutive patients with CAD who were admitted to the Research Institute for Complex Issues of Cardiovascular Diseases (Kemerovo, Russian Federation) during 2011–2012. Sample genotyping was performed in 96-well format using the TaqMan SNP genotyping assay. We found that C/C genotype of the rs3804099 polymorphism within TLR2 gene and T/T genotype of the rs4711668 polymorphism within TREM-1 gene were significantly associated with severe coronary atherosclerosis while C allele of the rs5743551 polymorphism within TLR1 gene, A/G genotype of the rs4986790 polymorphism and C/T genotype of the rs4986791 polymorphism within TLR4 gene, and C allele of the rs3775073 polymorphism within TLR6 gene were significantly associated with severe noncoronary atherosclerosis. However, A/A genotype of the rs5743810 polymorphism within TLR6 gene was significantly associated with mild noncoronary atherosclerosis. We conclude that certain TLR and TREM-1 gene polymorphisms are significantly associated with atherosclerosis severity in a Russian population.

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Rs3804099 polymorphism of TLR2 gene is associated with severe coronary atherosclerosis.

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Rs4711668 polymorphism of TREM-1 gene is associated with severe coronary atherosclerosis.

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Rs5743551 polymorphism of TLR1 gene is associated with severe noncoronary atherosclerosis.

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Rs4986790 and rs4986791 polymorphisms of TLR4 gene are associated with severe noncoronary atherosclerosis.

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Rs3775073 polymorphism of TLR6 gene is associated with severe noncoronary atherosclerosis.

Intensive Atorvastatin Therapy Attenuates the Inflammatory Responses in Monocytes of Patients with Unstable Angina Undergoing Percutaneous Coronary Intervention via Peroxisome Proliferator-Activated Receptor γ Activation

Periprocedural myocardial injury is a prognostically important complication of percutaneous coronary intervention (PCI). However, it still remains unclear whether and how intensive atorvastatin therapy attenuates the unfavorable inflammatory responses of monocytes associated with PCI. The aim of the study was to investigate the impact of intensive atorvastatin therapy on inflammatory responses of monocytes in Chinese patients with unstable angina who received PCI in order to explore the potential anti-inflammatory mechanism. Ninety-six patients with unstable angina were randomly assigned to atorvastatin 80 mg (intensive) or atorvastatin 20 mg (conventional) treatment at a 1:1 ratio. Creatine kinase MB (CK-MB), cTnI, hs-CRP, and IL-6 were assessed, and circulating CD14(+) monocytes were simultaneously obtained using CD14 MicroBeads 2 h before and 24 h after PCI. Plasma levels of CK-MB, cTnI, hs-CRP, and IL-6 were higher in the conventional dose group versus those in the intensive dose group following PCI. Furthermore, intensive atorvastatin treatment markedly reduced the expressions and responses of Toll-like receptor 2 (TLR2), TLR4, and CCR2 of CD14(+) monocytes versus the conventional dose group and significantly increased the activated peroxisome-proliferator-activated receptor (PPAR) γ in the CD14(+) monocytes post-PCI. Notably, the changes in responses of TLR2, TLR4, and CCR2 of CD14(+) monocytes between the two groups were all reversed by PPARγ antagonist and augmented by PPARγ agonist. In conclusion, a single high (80 mg) loading dose of atorvastatin reduced the inflammatory response in Chinese patients with unstable angina following PCI. The anti-inflammatory role of intensive atorvastatin was possibly due to attenuation of inflammatory response in monocytes via PPARγ activation.

Progression of carotid vascular damage and cardiovascular events in non-alcoholic fatty liver disease patients compared to the general population during 10 years of follow-up

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is associated not only with liver related morbidity and mortality but also with an increased risk of cardiovascular disease.

AIM

to evaluate in patients with NAFLD and in matched Controls after 10 years of follow-up 1 the incidence of major cardiovascular and cerebral events 2 the progression of vascular damage.

METHODS

Clinical and cardio-metabolic data were collected in 125 NAFLD patients and 250 age and gender matched Controls at baseline and 10 years later. Incidence of cardiovascular and cerebral events was recorded. By ultrasonography, carotid intima-media thickness (cIMT), presence of plaques and presence of fatty liver were evaluated.

RESULTS

25% of the overall series was lost to follow-up. Sixty-eight (37%) Controls developed steatosis. Major cardiovascular events were observed in thirty-five subjects (17/91 (19%) NAFLD and 18/182 (10%) Controls), with an estimated cumulative risk significantly higher in NAFLD than in Controls, log-rank test for equality of failure functions p = 0.007. At multivariate analysis, presence of plaques (hazard ratio 5.08 (95% C.I. 2.56-10.96) and of steatosis (hazard ratio 1.99 (1.01-3.94)) were the strongest predictors for cardiovascular events. Grade of steatosis, ALT and GGT levels were higher in NAFLD patients who developed cardiovascular events. cIMT value after 10 years was significantly higher in NAFLD than in Controls, but the mean progression rate was higher in Controls (0.015 and 0.006 mm/year, p = 0.001). In conclusion our results suggest that NAFLD has to be included among risk factors for cardiovascular damage and underline the utility to evaluate, once NAFLD is diagnosed, the presence of atherosclerotic lesions.

Association of TLR4 (D299G, T399I), TLR9 -1486T>C, TIRAP S180L and TNF-α promoter (-1031, -863, -857) polymorphisms with risk for systemic lupus erythematosus among South Indians

The rationale of this case-control study was to explore the association of Toll-like receptor 4 (TLR4) D299G, TLR4 T399I, TLR9 -1486 T>C, TIR-domain-containing adaptor protein (TIRAP) S180 L and tumor necrosis-α (TNF-α) promoter polymorphisms with susceptibility and phenotypic heterogeneity of systemic lupus erythematosus (SLE). PCR-RFLP, real-time PCR was used for the genetic analysis and expression studies and ELISA was used for the determination of specific autoantibodies. TLR4 D299G was associated with the risk for SLE (OR: 1.57, 95% CI: 1.08-2.28), while the TNF-α (-1031, -863, -857) CCC haplotype conferred protection. TLR4 and TIRAP polymorphisms were associated with reduced expression of HLA-DR. The presence of TLR4 and TLR9 polymorphisms increases the MHC2TA expression, while TIRAP polymorphism was associated with reduced expression. TLR4 D299 G showed an inverse association with pulmonary hypertension. TLR 4 T399I and TLR9 -1486 T>C showed a positive association with seizures and photosensitivity, respectively. TIRAP S180 L showed a positive association with alopecia and malar rashes, while an inverse association with psychosis was observed. TLR4 T399I (r = 0.14, p = 0.05) and TIRAP S180 L (r = 0.15, p = 0.03) showed a positive association with anti-Ro antibodies. On the other hand, TLR9 -1486 T>C showed an inverse association with anti-La antibodies (r = -0.20, p = 0.006). To conclude, TLR4 D299G increases the risk for SLE, while TNF-α CCC haplotype reduces the risk for SLE. All these polymorphisms contribute toward phenotypic heterogeneity. TLR4 T399I, TLR9 -1486 T>C and TIRAP S180 L influence specific autoantibody production in SLE.

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.

Associations of a TLR4 single-nucleotide polymorphism with H. pylori associated gastric diseases in Iranian patients

OBJECTIVE

Helicobacter pylori (H. pylori) is associated with gastric ulcer and gastric adenocarcinoma. Polymorphisms in the host genes coding for toll-like receptors (TLRs) may influence the innate and adaptive immune response to the infection, affecting the susceptibility to H. pylori or the disease outcomes. But the details and association to different polymorphisms and different clinical expressions in patients infected with H. pylori (different clinical expression of H. pylori infection) remain unclear.

METHODS

A case-control study consisting of 195 patients with H. pylori infection and 241 H. pylori uninfection was conducted. Genomic DNA was extracted and genotypes of TLR4Asp299Gly polymorphism were assessed through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Presence of cagA was evaluated using PCR.

RESULTS

TLR4 (Asp299Gly) G and DG alleles frequency in H. pylori infected population was significantly higher in the chronic gastritis group than in the chronic active gastritis group (P=0.021; OR, 2.409; 95% CI, 1.124-5.162). Grade mononuclear (MN) infiltration in H. pylori infected patients with DG genotype of TLR-4 Asp299Gly increased significantly. CagA positivity was more frequently associated with chronic active gastritis (P=0.017, OR=2.26, 95% CI=1.144-4.462) and grade polymorphonucler (PMN) infiltration.

CONCLUSION

TLR-4 Asp299Gly G allele substitution may be modified pattern of immune response in the gastric mucosa of H. pylori infected patients and may be H. pylori infected patients with gastritis have increased risk for the development of chronic gastritis. CagA positivity may be a risk factor for development of gastritis.

The Toll-like receptor 4 polymorphism Asp299Gly but not Thr399Ile influences TLR4 signaling and function

The common, co-segregating Toll-like receptor 4 (TLR4) non-synonymous single nucleotide polymorphisms (SNPs), Asp299Gly and Thr399Ile, are associated with hyporesponsiveness to inhaled lipopolysaccharide (LPS) and increased susceptibility to Gram negative pathogens in humans. The purpose of this study was to identify the relative contributions of the Asp299Gly and the Thr399Ile variants in inhibiting the function of TLR4. 293/hMD2-CD14 cell line was transfected with lentiviral constructs containing human wild type (WT) TLR4-EGFP or TLR4-EGFP with Asp299Gly, Thr399Ile or Asp299Gly/Thr399Ile complementary DNA (cDNA). Multiple stable cell lines were established for each construct: three for WT TLR4, Asp299Gly, and Thr399Ile, and only two for Asp299Gly/Thr399Ile mutants and EGFP control. We did not observe a significant effect of polymorphisms on cell surface and intracellular TLR4 expression nor were there any significant differences in TLR4 and EGFP protein levels assessed by Western blotting and confocal microscopy among the multiple cell lines of each of the constructs. All cell lines had a dose-dependent responsiveness to LPS stimulation. However, compared to the WT TLR4, cells expressing TLR4 with Asp299Gly but not Thr399Ile polymorphism produced significantly less (P<0.05) IL-8 following LPS stimulation. Similarly, cells expressing TLR4 Asp299Gly but not Thr399Ile allele had significantly lower percentage of phosphorylated and total NF-κB P65 following LPS stimulation. While we could not do statistics on the Asp299Gly/Thr399Ile group, we observed a reduced responsiveness to LPS compared to WT TLR4. Taken together, we observed that the TLR4 Asp299Gly variant, but not the Thr399Ile variant, is responsible for impaired responsiveness of TLR4 to LPS and corresponding activation of NF-κB.

Abdominal visceral fat measurement using dual-energy X-ray: association with cardiometabolic risk factors

OBJECTIVE

To examine the association between cardiometabolic risk factors and visceral adipose tissue (VAT) measurements using a dual-energy X-ray absorptiometry (DXA) based approach.

DESIGN AND METHODS

An analysis of cross-sectional relationships between DXA VAT measured using CoreScan (GE Healthcare) and cardiometabolic indicators was conducted on a sample of 939 subjects (541 females and 398 males; average age, 56 years; average BMI, 26 kg/m2) who had previously undergone a total body DXA scan as well as measurements of key cardiometabolic risk factors.

RESULTS

Sex-specific, age-adjusted multivariable regression analysis showed that for both men and women, DXA VAT was significantly associated with increased odds of hypertension, impaired fasting glucose, metabolic syndrome, and type 2 diabetes (P < 0.001). After additional model adjustment for BMI and waist circumference, the odds ratio (per SD change in VAT) for type 2 diabetes was 2.07 for women and 2.25 for men. Similarly, the odds ratio for metabolic syndrome for women was 3.46 and for men was 1.75.

CONCLUSIONS

VAT measured using DXA showed a significant association with cardiometabolic risk factors and disease. These relationships persist after statistical adjustment for age, BMI, and waist circumference. DXA VAT may provide a new accessible option for quantifying VAT-related cardiometabolic risk.

Correlation of Asp299Gly and Thr399Ile polymorphisms in toll-like receptor 4 gene with digestive cancer risk: A meta-analysis

The aim of this meta-analysis was to evaluate the correlation between the Asp299Gly and Thr399Ile polymorphisms in the toll-like receptor 4 (TLR4) gene and the risk of digestive cancer. A comprehensive search in PubMed, Web of Science (ISI), the China National Knowledge Infrastructure (CNKI), the Database of Chinese Scientific and Technical Periodicals (VIP) and the China Biology Medical (CBM) literature databases, including all the studies until May 25 2012, was conducted in order to investigate the abovementioned correlation. Statistical analysis was performed using STATA version 10.1. A total of 12 case-control studies were identified comprising 1,877 cancer patients and 3,181 controls for Asp299Gly polymorphism, and 8 case-control studies with 1,062 cancer patients and 1,867 controls for Thr399Ile polymorphism. Following sensitivity analysis and excluding studies that deviated from the Hardy-Weinberg equilibrium (HWE) in the controls, this meta-analysis demonstrated a significant correlation between the G allele of the Asp299Gly polymorphism and increased risk of gastric cancer in dominant [fixed-effect model (FEM): odds ratio (OR), 1.772; 95% confidence interval (CI), 1.340-2.343] and codominant (FEM: OR, 1.761, CI, 1.347-2.301) models. However, no significant correlation was detected for overall digestive and colorectal cancer. Furthermore, following the sensitivity analysis and exclusion of studies deviating from HWE in controls, no significant effect of the T allele of Thr399Ile polymorphism on overall digestive, gastric and colorectal cancer risk was demonstrated. This study suggests that the G allele of the TLR4 Asp299Gly polymorphism might be correlated with an increased risk of gastric cancer. However, this result needs to be further investigated by future studies.

Effector Memory T cells Are Associated With Atherosclerosis in Humans and Animal Models

BACKGROUND#ENTITYSTARTX02014;: Adaptive T-cell response is promoted during atherogenesis and results in the differentiation of naïve CD4(+)T cells to effector and/or memory cells of specialized T-cell subsets. Aim of this work was to investigate the relationship between circulating CD4(+)T-cell subsets and atherosclerosis. METHODS AND RESULTS#ENTITYSTARTX02014;: We analyzed 57 subsets of circulating CD4(+)T cells by 10-parameter/8-color polychromatic flow cytometry (markers: CD3/CD4/CD45RO/CD45RA/CCR7/CCR5/CXCR3/HLA-DR) in peripheral blood from 313 subjects derived from 2 independent cohorts. In the first cohort of subjects from a free-living population (n=183), effector memory T cells (T(EM): CD3(+)CD4(+)CD45RA(-)CD45RO(+)CCR7(-) cells) were strongly related with intima-media thickness of the common carotid artery, even after adjustment for age (r=0.27; P<0.001). Of note, a significant correlation between T(EM) and low-density lipoproteins was observed. In the second cohort (n=130), T(EM) levels were significantly increased in patients with chronic stable angina or acute myocardial infarction compared with controls. HLA-DR(+)T(EM) were the T(EM) subpopulation with the strongest association with the atherosclerotic process (r=0.37; P<0.01). Finally, in animal models of atherosclerosis, T(EM) (identified as CD4(+)CD44(+)CD62L(-)) were significantly increased in low-density lipoprotein receptor and apolipoprotein E deficient mice compared with controls and were correlated with the extent of atherosclerotic lesions in the aortic root (r=0.56; P<0.01). CONCLUSIONS#ENTITYSTARTX02014;: Circulating T(EM) cells are associated with increased atherosclerosis and coronary artery disease in humans and in animal models and could represent a key CD4(+)T-cell subset related to the atherosclerotic process. (J Am Heart Assoc. 2012;1:27-41.).

Association between OLR1 K167N SNP and intima media thickness of the common carotid artery in the general population

BACKGROUND AND PURPOSE

The lectin-like oxidised LDL receptor-1 (OLR1) gene encodes a scavenger receptor implicated in the pathogenesis of atherosclerosis. Although functional roles have been suggested for two variants, epidemiological studies on OLR1 have been inconsistent.

METHODS

We tested the association between the non-synonymous substitution K167N (rs11053646) and intima media thickness of the common carotid artery (CCA-IMT) in 2,141 samples from the Progression of Lesions in the Intima of the Carotid (PLIC) study (a prospective population-based study).

RESULTS

Significantly increased IMT was observed in male carriers of the minor C (N) allele compared to GC and GG (KN and KK) genotype. Functional analysis on macrophages suggested a decreased association to Ox-LDL in NN carriers compared to KN and KK carriers which is also associated with a reduced OLR1 mRNA expression. Macrophages from NN carriers present also a specific inflammatory gene expression pattern compared to cells from KN and KK carriers.

CONCLUSIONS

These data suggest that the 167N variant of LOX-1 receptor affects the atherogenic process in the carotid artery prior to evidence of disease through an inflammatory process.

Differential expression of Toll-like receptor 4 and human monocyte subsets in acute myocardial infarction

OBJECTIVE

To investigate the involvement of Toll-like receptor 4 (TLR4) expression on two monocyte subsets in the pathologic processes related to acute coronary syndrome. How monocytes, which have recently been shown to comprise two distinct subsets, mediate the process of coronary plaque rupture remains to be fully elucidated. Recent studies have shown that TLR4 is involved in monocyte activation of patients with accelerated forms of atherosclerosis.

METHODS

We enrolled 65 patients with acute myocardial infarction (AMI, n=22), unstable angina pectoris (UAP, n=16), and stable angina pectoris (SAP, n=27) who underwent coronary angiography and 15 healthy controls. The expression of TLR4 on two monocyte subsets (CD14(+)CD16(-) and CD14(+)CD16(+)) was measured by flow cytometry.

RESULTS

In patients with AMI, TLR4 was more expressed on circulating CD14(+)CD16(+) monocytes than on CD14(+)CD16(-) monocytes (p<0.001). The expression levels of TLR4 on CD14(+)CD16(+) monocytes were significantly elevated in patients with AMI compared with other 3 groups. TLR4 expression levels on CD14(+)CD16(+) monocytes were significantly elevated at the culprit site compared with the systemic level (p=0.044). The up-regulation of TLR4 on admission was remarkably decreased 12 days after AMI (p<0.001). In addition, plasma levels of tumor necrosis factor-α were positively correlated with TLR4 expression levels on monocytes in patients with AMI (r=0.47, p=0.027).

CONCLUSION

TLR overexpression on CD14(+)CD16(+) monocytes in AMI, as demonstrated both in the circulation and at the coronary culprit site, might be associated with the pathogenesis of AMI.

Coactivation of TLR4 and TLR2/6 coordinates an additive augmentation on IL-6 gene transcription via p38MAPK pathway in U937 mononuclear cells

Studies have demonstrated that TLR4 and TLR2 expression by monocytes and the blood levels of TLR4 and TLR2 ligand in diabetic patients are significantly incased compared to nondiabetic patients, indicating that more monocytes in diabetic patients may have coactivation of TLR4 and TLR2. Although it has been shown that either TLR4 or TLR2 activation leads to increased expression of proinflammatory cytokines, the effect of coactivation of TLR2 and TLR4 in mononuclear cells on proinflammatory cytokine expression and the underlying molecular mechanisms remain largely unknown. In this study, we found that while TLR1, TLR2, TLR4 and TLR6 were expressed by U937 mononuclear cells, TLR4 was expressed at the highest level. Interestingly, results showed that while activation of either TLR4 or TLR2/6 (TLR2dimerized with TLR6), but not TLR2/1 (TLR2dimerized with TLR1), significantly increased IL-6 expression by U937 mononuclear cells, coactivation of TLR4 and TLR2/6, but not TLR4 and TLR2/1, led to a further augmentation on IL-6 expression by increasing IL-6 transcriptional activity, but not mRNA stability. To explore the signaling mechanisms involved in the augmentation, we found that p38MAPK and NFκB pathways, but not ERK and JNK pathways, were required for the augmentation of IL-6 expression by coactivation of TLR4 and TLR2/6. Furthermore, we found that coactivation of TLR4 and TLR2/6 increased p38 phosphorylation, but not NFkB activity, as compared to activation of TLR4or TLR2/6 alone. Taken together, this study showed that coactivation of TLR4 and TLR2/6 coordinates an additive augmentation of IL-6 gene transcription via p38MAPK pathway in U937 mononuclear cells.

Polymorphisms in Toll-like receptor 4 are associated with factors of the metabolic syndrome and modify the association between dietary saturated fat and fasting high-density lipoprotein cholesterol

Toll-like receptor 4 (TLR4) is a protein of the innate immune system hypothesized to mediate some of the effects of a high-fat diet on inflammation and insulin resistance. As both these factors are associated with the metabolic syndrome (MetS), genetic variation in TLR4 may affect the relationship between dietary lipids and MetS. The objective of the study was to determine whether 2 polymorphisms in TLR4 (rs4986790 Asp299Gly and rs5030728 G>A) modify the relationship between dietary fat and markers of the MetS. Participants were healthy young men and women of various ethnocultural backgrounds. Dietary intake was estimated using a 1-month semiquantitative food frequency questionnaire, and fasting blood samples were taken for genotyping and biomarker measurement. The Asp299Gly polymorphism in TLR4 was associated with increased insulin, homeostasis model assessment of insulin resistance (P < .05), and homeostasis model assessment of β-cell function (P < .05) and family history of diabetes (P = .0002). The intronic polymorphism rs5030728 modified the relationship between dietary saturated fatty acids (SFAs) and high-density lipoprotein (HDL) cholesterol (P = .003 for interaction). The SFA intake was inversely associated with HDL cholesterol among individuals homozygous for the G allele (β = -0.015 ± 0.007 mmol/L, P = .04), whereas a positive relationship was observed for heterozygotes (β = 0.025 ± 0.01 mmol/L, P = .02). There was no association between dietary SFAs and HDL cholesterol among individuals homozygous for the A allele. These observations suggest that both diet and innate immunity may interact to influence components of the MetS.

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.

Genetic variants in TLR2 and TLR4 are associated with markers of monocyte activation: the Atherosclerosis Risk in Communities MRI Study

Markers of monocyte activation play a critical role in atherosclerosis, but little is known about the genetic influences on cellular levels. Therefore, we investigated the influence of genetic variants in monocyte differentiation antigen (CD14), toll-like receptor-4 (TLR4), toll-like receptor-2 (TLR2), and myeloperoxidase (MPO) on monocyte surface receptor levels. The study sample consisted of 1,817 members of a biracial cohort of adults from the Atherosclerosis Risk in Communities Carotid MRI Study. Monocyte receptors were measured using flow cytometry on fasting whole blood samples. TLR2 rs1816702 genotype was significantly associated with CD14+/TLR2+ percent of positive cells (%) and median fluorescence intensity (MFI) in whites but not in blacks (p < 0.001). Specifically, the presence of the minor T-allele was associated with increased receptor levels. In blacks, TLR4 rs5030719 was significantly associated with CD14+/TLR4+ monocytes (MFI) with mean ± SE intensities of 16.7 ± 0.05 and 16.0 ± 0.14 for GG and GT/TT genotypes, respectively (p < 0.001). Variants in TLR2 and TLR4 were associated with monocyte receptor levels of TLR2 and TLR4, respectively, in a biracial cohort of adults. To our knowledge, this is the first study to look at associations between variants in the toll-like receptor family and toll-like receptor levels on monocytes.

Carotid plaque and candidate genes related to inflammation and endothelial function in Hispanics from northern Manhattan

BACKGROUND AND PURPOSE

The genetic influence on carotid atherosclerotic plaque is mostly unknown. This study examines the association between carotid plaque and single nucleotide polymorphisms in selected genes implicated in inflammation and endothelial function.

METHODS

A total of 43 genes (197 single nucleotide polymorphisms) involved in inflammation and endothelial function were interrogated in 287 Dominicans from the Northern Manhattan Study (mean age, 64±7 years; 58% women) who had undergone high-resolution B-mode ultrasound for examination of carotid plaque. Using an additive genetic model, multiple logistic regression analyses were conducted, a within-gene haplotype analysis was performed, and interactions between genes were examined. Results were validated in an independent set of 301 Dominicans.

RESULTS

Carotid plaque was present in 143 (47%) participants. Nine genes had at least 1 single nucleotide polymorphism associated (P≤0.01) with carotid plaque phenotypes: TNF, NOS2A, IL6R, TNFSF4, PPARA, IL1A, TLR4, ITGA2, and HABP2. Single nucleotide polymorphisms in TNFSF4, PPARA, TLR4, ITGA2, and HABP2 were also implicated with the same carotid phenotype in the validation analysis. Haplotype analysis revealed an additional gene of interest, VCAM1.

CONCLUSIONS

We report novel associations between variations in 10 genes involved in inflammation and endothelial function and carotid plaque phenotypes in a Dominican sample, with replication for 5 genes in an independent Dominican sample.

LPS-mediated production of pro/anti-inflammatory cytokines and eicosanoids in whole blood samples: biological effects of +896A/G TLR4 polymorphism in a Sicilian population of healthy subjects

Toll-like receptors (TLRs) are the principal mediators of rapid microbial recognition: the lipopolysaccharide (LPS) receptor TLR4 seems to have a paradigmatic role. Single nucleotide polymorphisms (SNPs) in the TLR4 gene, such as +896A/G, known to attenuate receptor signaling, have been described. The +896A/G SNP is significantly less frequent in patients with myocardial infarction, Alzheimer's disease or prostate cancer, whereas it is overrepresented in centenarians. To clarify and confirm the biological effects of +896A/G SNP and its role in the pathophysiology of age-related diseases and longevity, we assessed the levels of IL-6, TNF-α, IL-10 and eicosanoids (LTB4 and PGE2) in LPS-stimulated whole blood samples in vitro of 50 young healthy Sicilians, screened for the presence of this SNP. To evaluate the possible influence of SNPs in PTGS2 and 5-Lo genes on eicosanoid production, the enrolled individuals were also genotyped for -765G/C PTGS2 and -1708G/A 5-Lo SNPs. Both pro-inflammatory cytokines and eicosanoids were significantly lower in carriers bearing the TLR4 mutation, whereas the anti-inflammatory IL-10 values were higher. On the basis of data reported herein, some suggestions can be drawn. First, pathogen load, by interacting with the host genotype, determines the type and intensity of inflammatory responses, according to the pro-inflammatory status and tissue injury, implicated in the pathophysiology of major age-related diseases. Second, adequate control of inflammatory response might reduce the risk of these diseases, and, reciprocally, might increase the chance of extended survival in an environment with reduced antigen (that is, pathogen) load.

Biomarkers of vulnerable plaque: the missing link with ischemia

The initial evaluation of chest pain in the emergency department is based on the patient’s clinical history, changes in the ECG and necrosis biomarkers. Although management of patients with ST-elevation myocardial infarction or non-ST-elevation myocardial infarction with positive markers of myocardial damage is well defined, exclusion of coronary artery disease or myocardial ischemia in the remaining patients is more challenging. This group represents the majority of patients admitted for chest pain syndromes and that have a substantial risk of an adverse outcome. Given that troponin, as a marker of myocardial damage, detects terminal events in the cascade of acute coronary syndrome, there is a need to search for biomarkers that are able to identify patients at high risk, allowing rapid, bedside stratification. Data suggest that clinical events are prone to occur more frequently in patients with coronary artery stenosis associated with myocardial ischemia. Accordingly, identification of systemic biomarkers of ischemia could facilitate identification of high-risk patients with a high burden of coronary atherosclerosis and plaque rupture. We describe six biomarkers that have been linked to myocardial ischemia. Until now, these biomarkers of ischemia are relevant in order to exclude ischemic heart disease (high negative predictive value) but still lack specificity. Future prospective studies should be performed in larger and more diverse sets of patients presenting with ischemia, and in a complementary fashion in order to provide valuable tools for clinical decision making.

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.

Plasma adiponectin levels in chronic kidney disease patients: relation with molecular inflammatory profile and metabolic status

BACKGROUND AND AIM

Adiponectin (ADPN) exerts anti-inflammatory and cardio protective effects and is associated with decreased cardiovascular risk, however its role in patients with chronic kidney disease is unclear.

METHODS AND RESULTS

We investigated the correlation between plasma ADPN levels, the progression of CVD and CKD and the inflammatory gene expression profile of peripheral blood mononuclear cells in patients from the NephroPLIC study (a prospective study aimed at addressing the progression of cardiovascular damage in relation to kidney dysfunction). Plasma ADPN levels were directly correlated with age, HDL-C and creatinine, and inversely with BMI, triglycerides and glomerular filtration rate (GFR). Multiple regression analysis identified plasma creatinine and HDL as the independent factors associated with ADPN plasma levels. In peripheral blood mononuclear cells (PBMC), the mRNA expression of MCP-1, CD40, Cox-2, TLR4, PAI-1, TNF alpha, resistin and RAGE was up-regulated in the group with higher GFR and higher ADPN plasma levels compared to that with low GFR and ADPN plasma levels. Patients with similar GFR values showed no differences in the gene expression profile of PBMC although ADPN levels were associated with decreased CRP and IL-6 plasma levels and decreased IMT and heart left ventricular mass.

CONCLUSION

In CKD patients who are not in dialysis ADPN plasma levels are associated with a reduced renal excretory function, but correlate inversely with the determinants of the metabolic syndrome such as glucose, triglycerides and BMI, and directly with HDL. Furthermore, in patients with a similar degree of renal impairment, ADPN plasma levels are associated with a better cardiometabolic profile, despite no significant difference being observed in the gene expression pattern of PBMC.

Effects of PCSK9 variants on common carotid artery intima media thickness and relation to ApoE alleles

BACKGROUND

PCSK9 plays a key role in plasma cholesterol metabolism by modulating the expression of LDL receptors.

OBJECTIVE AND METHODS

In this study we investigated the effects of two common polymorphism of the PCSK9 gene (E670G and I474V) on the intima media thickness of the common carotid artery and the possible relation with polymorphisms of apolipoprotein E in 1541 middle aged subjects selected from the general population enrolled in the PLIC study and confirmed the major findings in a second free-living population enrolled in the Ventimiglia study.

RESULTS

670G carriers showed significantly increased plasma total cholesterol, LDL-cholesterol, and Apo levels B while no significant differences were observed between carriers of the I474V SNP. IMT was significantly increased in 670G carriers compared to individuals homozygous for the E allele (0.640+/-0.102mm vs. 0.652+/-0.092mm, P<0.05). The presence of the 670G allele was also significantly associated with a greater progression of IMT compared to 670EE subjects. Plasma total cholesterol, LDL-cholesterol, apolipoprotein B, and IMT significantly increased from ApoE2;PCSK9-670EE carriers to ApoE4-PCSK9-670G carriers, while no significant differences were observed when the presence of the ApoE alleles was combined with that of the PCSK9 I474V SNP. In silico analysis on wild type and 670G variant showed several structural differences on the interactions of the loops of the "V" domain.

CONCLUSIONS

The E670G polymorphism of the PCSK9 gene is associated with increased IMT progression in the general population. When the presence of 670G allele is stratified according to the ApoE gene alleles, ApoE2;PCSK9-670EE carriers show a more favorable plasma lipid profile and decreased IMT compared to ApoE4-PCSK9-670G carriers.

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.

Small dense LDL and VLDL predict common carotid artery IMT and elicit an inflammatory response in peripheral blood mononuclear and endothelial cells

OBJECTIVE

The presence of small dense LDL has been associated with increased cardiovascular risk and with the progression of coronary and carotid atherosclerosis in case-control and prospective studies. The aim of this study was to investigate the relation between different lipoprotein subfractions with intima-media thickness of the common carotid artery in a free-living, healthy population, and to evaluate whether in patients with comparable LDL-C, the different lipoprotein subclasses differently affected the expression of chemokines, cytokines and adhesion molecules in peripheral blood mononuclear and endothelial cells.

METHODS AND RESULTS

The lipoprotein cholesterol profile and the LDL buoyancy (LDL-RF) were evaluated in a cohort of 156 healthy subjects randomly selected from the PLIC (Progressione Lesione Intimale Carotidea) study. The LDL-RF was directly and significantly correlated to weight, body mass index, waist, hip, waist/hip ratio, triglycerides, fasting glycemia and intima media thickness (IMT) of the common carotid artery and inversely related to HDL-C. After multivariate statistical analysis, IMT was independently associated with age, LDL-RF and HDL-C and among the lipoprotein subclasses, only those corresponding to triglyceride-rich lipoproteins (TGRL) and small dense LDL (sdLDL) independently predicted IMT variance. Peripheral blood mononuclear cells (PBMC) isolated from patients with the predominance of sdLDL (pattern B) had an increased mRNA expression of pro-inflammatory molecules compared to PBMC from patients with the predominance of large LDL (pattern A); in endothelial cells TGRL from pattern B subjects and much less those from pattern A induced the expression of pro-inflammatory genes while sdLDL from either pattern A or B subjects were less effective and showed comparable effects.

CONCLUSION

LDL-relative flotation rate significantly correlates with several cardiometabolic parameters. Furthermore cholesterol levels lipoprotein subfractions within the TGRL and sdLDL density range are independent predictors of IMT variance and are associated with a pro-inflammatory activation of PBMC and endothelial cells.

Circulating soluble receptor for advanced glycation end products is inversely associated with body mass index and waist/hip ratio in the general population

Advanced glycation end products, AGEs, and its specific receptor, RAGE, are involved in vascular complications. A role for the soluble form of RAGE (sRAGE), which acts as a decoy for AGE, has been documented in patients with diabetes but no information is available in non-diabetic subjects. The aim of this study was to investigate the association of plasma levels of sRAGE with cardiometabolic risk factors in the general population. In addition we evaluated the relation of the common -374A/T polymorphism of RAGE with plasma levels of sRAGE. One hundred and seventy-six healthy subjects free of diabetes or coronary artery disease untreated for hypertension, dyslipidemia or cardiometabolic related diseases were randomly selected for this study from the general population. Plasma sRAGE were negatively and significantly correlated with BMI, waist/hip circumference ratio and fasting glycemia, while a positive correlation was observed with apolipoprotein A-I. These correlations were observed mainly in women who showed significantly higher sRAGE levels (1744+/-660 pg/mL vs 1414+/-649 pg/mL; P<0.05). In a stepwise regression analysis waist circumference was independently associated with sRAGE and, when waist circumference was excluded, BMI was independently associated with sRAGE. Finally in overweight subjects (BMI>25 kg/m(2)) plasma sRAGE was significantly lower compared to lean subjects (1460+/-640 pg/mL vs 1710+/-693 pg/mL; P<0.05). In healthy subjects plasma levels of sRAGE were negatively correlated with BMI and waist/hip ratio supporting a possible protective role for these proteins before any evidence of diabetic or vascular complications.

Toll-like receptor modulation: a novel therapeutic strategy in cardiovascular disease?

BACKGROUND

Toll-like receptors (TLRs) have been recently recognised as primary receptors in the innate immune system. Apart from initiating a prompt immune response against invading pathogens, TLRs are also considered to be an important link between innate immunity, inflammation and a variety of clinical disorders, including cardiovascular diseases. TLR signalling manipulation with novel drugs could offer important opportunities for cardiovascular disease modification.

OBJECTIVE

To present the latest knowledge supporting the involvement of TLRs in the pathogenesis and progress of cardiovascular diseases and explore the role of TLRs as potential targets for therapeutic intervention in cardiovascular territory.

METHODS

A review of the literature documenting implication of TLR signalling in cardiovascular disorders. Current progress in TLR-targeting drug development and the potential role of such a treatment strategy in cardiovascular disorders are discussed.

CONCLUSIONS

A growing body of evidence supports a role for TLRs in cardiovascular disease initiation and progression. Altering TLR signalling with novel drugs could be a beneficial therapeutic strategy for patients with cardiovascular disorders.

[Polymorphisms of the Toll-like receptor 4 gene and their potential role in infectious diseases and chronic inflammatory disorders]

The Toll-like receptor 4 is a key mediator of the innate immune response. Besides its main ligand, the Gram-negative bacterial lipopolysaccharides, other molecules such as heat-shock protein 60, oxidized low density lipoprotein and fibronectin can also bind to the receptor. Activation of the Toll-like receptor induces the production of proinflammatory cytokines. There is increasing evidence showing that the Toll-like receptor 4 plays a role not only in the immune reaction against infectious agents but also in chronic non-infectious inflammatory diseases, such as atherosclerosis, diabetes mellitus and inflammatory bowel disease. This review briefly summarizes recent knowledge on the Toll-like receptor 4, its common co-segregation polymorphisms and the impact of these polymorphisms on various human diseases.

TLR4 single-nucleotide polymorphisms alter mucosal cytokine and chemokine patterns in Mexican patients with Helicobacter pylori-associated gastroduodenal diseases

Helicobacter pylori is associated with peptic ulcer and gastric adenocarcinoma. Toll-like receptors (TLRs) participate in H. pylori recognition, and single-nucleotide polymorphisms (SNPs) in TLRs are associated with impaired immune response. We aimed to evaluate the association of TLR2/R753Q and TLR4/D299G/T399I SNPs with gastroduodenal diseases; and study the effect of SNPs on cytokine and chemokine expression in the gastric mucosa. Study included 450 Mexican patients with gastroduodenal diseases. SNPs in TLRs 2 and 4 genes were analyzed by allele-specific PCR. Cytokines and chemokines were assessed by qRT-PCR and immunoassay. TLR4/D299G/T399I polymorphisms were more frequent in duodenal ulcer and showed a trend in gastric cancer, when compared with non-atrophic gastritis. Patients with TLR4 polymorphisms expressed significantly lower levels of IL-1beta, IL-6, IL-8 and GRO-alpha; and higher levels of TNF-alpha, IL-10, MCP-1 and MIP-1alpha . SNPs in TLR4 gene had an association with severe H. pylori-associated disease and with modified pattern of inflammatory cytokines and chemokines in the gastric mucosa. These results suggest that TLR4 SNPs contributes importantly to the clinical outcome of H. pylori infection.

Functional consequences of toll-like receptor 4 polymorphisms

Toll-like receptor 4 (TLR4) is an important pathogen recognition receptor that recognizes mainly lipopolysaccharide (LPS) of Gram-negative bacteria, but also structures from fungal and mycobacterial pathogens, as well as endogenous ligands. Two nonsynonymous polymorphisms of TLR4, Asp299Gly and Thr399Ile, have been suggested to alter the function of the receptor. Some, but not all, studies have proposed that these polymorphisms lead to reduced cytokine response and increased susceptibility to Gram-negative infections. In this review, we compare studies that assessed the effect of the Asp299Gly and Thr399Ile polymorphisms on susceptibility to Gram-negative infections and examine the phenotypic consequences of these polymorphisms. In addition, we review the geographical distribution of TLR4 polymorphisms and present a model for evolutionary pressures on the TLR4 genetic make-up.

Cholesterol ester transfer protein, interleukin-8, peroxisome proliferator activator receptor alpha, and Toll-like receptor 4 genetic variations and risk of incident nonfatal myocardial infarction and ischemic stroke

Variations in candidate genes participating in oxidative stress, inflammation, and their interactions are potentially associated with diseases of atherosclerotic origin. We investigated independent and joint associations of variations in cholesterol ester transfer protein (CETP), interleukin-8 (IL8), peroxisome proliferator activator receptor-alpha (PPARA), and Toll-like receptor 4 (TLR4) genes with incident nonfatal myocardial infarction (MI) or ischemic stroke. In a population-based case-control study, patients (848 with MI and 368 with ischemic stroke) and controls (2,682) were recruited from postmenopausal women and hypertensive men/women who were members of Group Health in western Washington State. Common tag single-nucleotide polymorphisms (SNPs; n=34) representing gene-wide variations were selected from gene sequencing data using pairwise linkage disequilibrium. Haplotypes were inferred using a modified expectation maximization algorithm. Multivariate logistic regression evaluated individual haplotype and SNP-disease associations in log-additive models. Global haplotype tests assessed overall gene-disease associations. Logic regression was used to evaluate gene-gene interactions. False discovery rates and permutation tests were used for multiple testing adjustment in evaluating independent associations and interactions, respectively. Overall, gene-wide variations in PPARA and TLR4 genes were associated with MI. The minor allele of the PPARA SNP, rs4253623, was associated with a higher risk of MI (odds ratio 1.25, 95% confidence interval 1.08 to 1.46), whereas the minor allele of the TLR4 SNP, rs1927911, was associated with a lower risk of MI (odds ratio 0.88, 95% confidence interval 0.77 to 0.99). No within-gene or gene-gene interaction was associated with MI or ischemic stroke risk. In conclusion, potential SNP-disease associations identified in the present study are novel and need further investigation.

Carotid artery intima-media thickness in nonalcoholic fatty liver disease

PURPOSE

To evaluate, in patients with nonalcoholic fatty liver disease with no or mild alterations of liver function tests, carotid artery intima-media thickness and the presence of plaques and to define determinants of vascular damage.

METHODS

A paired-sample case-control study: 125 patients with nonalcoholic fatty liver disease and 250 controls, without a prior diagnosis of diabetes, hypertension, and cardiovascular disease, matched for sex, age, and body mass index. B-mode ultrasound was used for evaluation of carotid intima-media thickness and presence of small plaques.

RESULTS

A significant difference in mean values of intima-media thickness (0.89+/-0.26 and 0.64+/-0.14 mm, P = .0001) and prevalence of plaques (26 [21%] and 15 [6%], P < .001) was observed in nonalcoholic fatty liver disease patients and controls. Variables significantly associated with intima-media thickness higher than 0.64 mm (median value in controls), in both patients and controls were: age (P = .0001), systolic blood pressure (P = .004), total and low-density lipoprotein cholesterol (P < or = .02 and P = .01, respectively), fasting glucose (P = .0001), and cardiovascular risk (P = .0001) and, only in controls, metabolic syndrome (P = .0001), HOMA-insulin resistance (P = .01), and body mass index (P = .0003). At multivariate logistic regression performed in the overall series of subjects, independent risk predictors of intima-media thickness higher than 0.64 mm were presence of steatosis (odds ratio [OR] = 6.9), age (OR 6.0), and systolic blood pressure (OR 2.3).

CONCLUSION

Patients with nonalcoholic fatty liver disease, even with no or mild alterations of liver tests, should be considered at high risk for cardiovascular complications.

Toll-like receptor 4 gene (Asp299Gly) polymorphism associates with carotid artery elasticity. The cardiovascular risk in young Finns study

OBJECTIVE

Early subclinical markers of atherosclerosis, such as carotid artery intima media thickness (IMT) and elasticity predict future coronary events. The G allele of the Toll-like receptor 4 (TLR-4) gene Asp299Gly polymorphism has been previously associated with decreased development of atherosclerosis and with lower risk of myocardial infractions. We wanted to examine the association of this polymorphism with carotid IMT and compliance in a population of young Finnish Caucasian adults.

METHODS

Carotid artery IMT and elasticity indices of 2201 study subjects who participated in a randomized multicenter study (cardiovascular risk in young Finns study) were measured with ultrasound. The genotyping was performed using the TaqMan 5'-nuclease assay.

RESULTS

According to multivariate linear regression analysis adjusted with potential confounders, the G allele carriers had significantly higher carotid arterial compliance, measured in increase of luminal diameter percentage in response to blood pressure rise of 10 mmHg, than did the AA homozygotes (beta=0.099 with 95% CI 0.029-0.169 and p=0.006). The difference between AA homozygotes and GG homozygotes was even more pronounced (beta=0.382 with 95% CI 0.119-0.644 and p=0.004). Variation in the TLR-4 genotype was not related with IMT. The results of the two independent study cohorts of Eastern and Western Finland were in accordance with the results of the whole combined study population.

CONCLUSION

The G allele of the TLR-4 gene Asp299Gly polymorphism is associated with increased carotid artery compliance in young adults. This beneficial effect of the G allele may reduce the risk of future cardiovascular events.

Deficiency of Cbl-b gene enhances infiltration and activation of macrophages in adipose tissue and causes peripheral insulin resistance in mice

OBJECTIVE

c-Cbl plays an important role in whole-body fuel homeostasis by regulating insulin action. In the present study, we examined the role of Cbl-b, another member of the Cbl family, in insulin action.

RESEARCH DESIGN AND METHODS

C57BL/6 (Cbl-b(+/+)) or Cbl-b-deficient (Cbl-b(-/-)) mice were subjected to insulin and glucose tolerance tests and a hyperinsulinemic-euglycemic clamp test. Infiltration of macrophages into white adipose tissue (WAT) was assessed by immunohistochemistry and flow cytometry. We examined macrophage activation using co-cultures of 3T3-L1 adipocytes and peritoneal macrophages.

RESULTS

Elderly Cbl-b(-/-) mice developed glucose intolerance and peripheral insulin resistance; serum insulin concentrations after a glucose challenge were always higher in elderly Cbl-b(-/-) mice than age-matched Cbl-b(+/+) mice. Deficiency of the Cbl-b gene significantly decreased the uptake of 2-deoxyglucose into WAT and glucose infusion rate, whereas fatty liver was apparent in elderly Cbl-b(-/-) mice. Cbl-b deficiency was associated with infiltration of macrophages into the WAT and expression of cytokines, such as tumor necrosis factor-alpha, interleukin-6, and monocyte chemoattractant protein (MCP)-1. Co-culture of Cbl-b(-/-) macrophages with 3T3-L1 adipocytes induced leptin expression and dephosphorylation of insulin receptor substrate 1, leading to impaired glucose uptake in adipocytes. Furthermore, Vav1, a key factor in macrophage activation, was highly phosphorylated in peritoneal Cbl-b(-/-) macrophages compared with Cbl-b(+/+) macrophages. Treatment with a neutralizing anti-MCP-1 antibody improved peripheral insulin resistance and macrophage infiltration into WAT in elderly Cbl-b(-/-) mice.

CONCLUSIONS

Cbl-b is a negative regulator of macrophage infiltration and activation, and macrophage activation by Cbl-b deficiency contributes to the peripheral insulin resistance and glucose intolerance via cytokines secreted from macrophages.

Mechanisms of disease: Toll-like receptors in cardiovascular disease

The innate immune system detects highly conserved, relatively invariant structural motifs of pathogens. Toll-like receptors (TLRs) have been identified as the primary innate immune receptors. TLRs distinguish between different patterns of pathogens and activate a rapid innate immune response; however, TLRs can also be activated by host-derived molecules. In addition to being expressed in immune cells, TLRs are expressed in other tissues, such as those of the cardiovascular system. TLRs could, therefore, be a key link between cardiovascular disease development and the immune system. Indeed, evidence that TLR activation contributes to the development and progression of atherosclerosis, cardiac dysfunction in sepsis, and congestive heart failure, is convincing. Although much has been learned about TLR activation in cellular components of the cardiovascular system, the role individual TLR family members have in the pathophysiology of cardiovascular diseases and hence in clinical practice remains to be defined. Here we review the rapid progress that has been made in this field, which has improved our understanding of vascular as well as myocardial TLR function in basic and clinical science.

Leptin:adiponectin ratio is an independent predictor of intima media thickness of the common carotid artery

BACKGROUND AND PURPOSE

The evaluation of the leptin:adiponectin ratio (L:A) has been suggested as an atherosclerotic index in patients with type 2 diabetes and a useful parameter to assess insulin resistance in patients with and without diabetes.

METHODS

We investigated, therefore, the relationship between L:A ratio and intima media thickness (IMT), an independent predictor of cardiovascular disease, in 110 healthy males.

RESULTS

L:A ratio was significantly correlated to body mass index, waist, hip, waist-to-hip ratio, systolic blood pressure, IMT, high-density lipoprotein, apolipoprotein A-I, glucose, and the homeostasis model of insulin resistance-revised. No significant correlation was observed with age, diastolic blood pressure, low-density lipoprotein, triglycerides, apolipoprotein B, ApoB/ApoA-I ratio, insulin, alanine transaminase, gamma-glutamyl-transferase, and resistin. In addition, when the relationship between IMT and adiponectin or leptin alone was analyzed, only leptin plasma levels significantly associated with IMT (r=0.301, P<0.01). In a multiple regression analysis including in the statistical model the risk factors known to affect IMT (age, systolic blood pressure, diastolic blood pressure, high-density lipoprotein cholesterol, triglycerides, total cholesterol, body mass index, glucose, and L:A ratio), we observed that only age, L:A, and glucose were independent predictors of IMT. As expected, obese subjects (body mass index >30 kg/m(2)) showed a significantly higher L:A ratio compared with nonobese subjects (1.20 versus 0.42, respectively, P<0.001); in addition, subjects with the metabolic syndrome showed a significantly higher L:A ratio level (0.79) compared with subjects without (0.52) (P<0.01).

CONCLUSIONS

We show here that the L:A ratio is a powerful independent predictor of IMT in healthy subjects and correlates with several anthropometric, metabolic, and clinical parameters better than each single adipokine.

Effect of the -420C/G variant of the resistin gene promoter on metabolic syndrome, obesity, myocardial infarction and kidney dysfunction

OBJECTIVE

Resistin is an adipokine that has been suggested to be correlated with markers of inflammation and to be predictive of coronary atherosclerosis and type II diabetes in humans. A common single nucleotide polymorphism (SNP) (-420C/G) in the promoter of resistin is associated with increased resistin plasma levels and susceptibility to type II diabetes. The aim of this study was to investigate the association of the -420C/G polymorphism with metabolic syndrome, obesity, myocardial infarction and kidney disease.

DESIGN AND RESULTS

First we studied 1542 subjects from the PLIC study (a population based cohort). GG carriers showed an higher prevalence of obesity and metabolic syndrome as well as increased plasma triglycerides levels, BMI, systolic and diastolic blood pressure and cardiovascular risk according to Framingham algorithm (P < 0.05 for all). Next we investigated the presence of the -420C/G resistin polymorphism in a case-control study that included 300 subject with myocardial infarction and 300 age and sex matched controls and then we studied the role of the -420C/G SNP in 88 patients with mild to moderate renal dysfunction. No statistically significant differences in allele frequencies between the PLIC study, the myocardial infarction (MI) cases and the subjects with renal dysfunction were observed. Pro-inflammatory gene expression profiling of peripheral blood mononuclear cells failed to detect any difference between wild type subjects and carriers of the rare allele.

CONCLUSION

Our data suggest that the presence of the -420C/G SNP of the resistin gene is associated with increased obesity and metabolic syndrome, although it is not different in subjects at high cardiovascular risk such as patients with myocardial infarction or patients with renal dysfunction compared with controls.