CD14 and toll-like receptor 4: a link between infection and acute coronary events?

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 C260T promoter polymorphism and the risk of cerebrovascular diseases: a meta-analysis

Cerebrovascular diseases (CVD) are dysfunctions of the brain, resulting from diseases of blood vessels supplying the brain. Atherosclerosis is one of the major underlying causes of CVD, in which inflammation plays a crucial role. One of the inflammatory mechanisms contributing to atherogenesis is the activation of monocytes and macrophages, which could be mediated by the bacterial endotoxin lipopolysaccharide (LPS) via its receptor CD14. The C260T (rs2569190) single-nucleotide polymorphism (SNP) in the promoter region of the CD14 gene was implicated in CVD. To assess the role of this SNP in CVD, a comprehensive meta-analysis of the available genetic data was conducted. All the case-control association studies evaluating the role of CD14 C260T in CVD were identified. Of these, 7 studies (comprising a total of 1488 patients and 1600 control subjects) were included in this meta-analysis. To measure the strength of genetic association for the gene variant, the odds ratios (ORs) were calculated using both fixed and random effects for comparisons of the alleles, the genotypes, and the dominant and recessive genotype models. The results showed there was no significant association between the T allele of C260T and the risk of CVD under the fixed effects model, OR = 0.99 (95% CI (0.89, 1.09)), P = 0.84; or the random effects model, OR = 0.99 (95% CI (0.88, 1.11)), P = 0.83. Similar results were obtained for the homozygotes and the dominant and recessive models. In conclusion, the results of this meta-analysis suggest the CD14 C260T polymorphism is not a risk factor for CVD. However, more studies in ethnically varied populations are needed to evaluate in a reliable manner the role of this SNP in CVD susceptibility.

The inflammatory status of the elderly: the intestinal contribution

A common finding in the elderly population is a chronic subclinical inflammatory status that coexists with immune dysfunction. These interconnected processes are of sufficient magnitude to impact health and survival time. In this review we discuss the different signals that may stimulate the inflammatory process in the aging population as well as the molecular and cellular components that can participate in the initiation, the modulation or termination of the said process. A special interest has been devoted to the intestine as a source of signals that can amplify local and systemic inflammation. Sentinel cells in the splanchnic area are normally exposed to more than one stimulus at a given time. In the intestine of the elderly, endogenous molecules produced by the cellular aging process and stress as well as exogenous evolutionarily conserved molecules from bacteria, are integrated into a network of receptors and molecular signalling pathways that result in chronic inflammatory activation. It is thus possible that nutritional interventions which modify the intestinal ecology can diminish the pro-inflammatory effects of the microbiota and thereby reinforce the mucosal barrier or modulate the cellular activation pathways.

Molecular or pharmacologic inhibition of the CD14 signaling pathway protects against burn-related myocardial inflammation and dysfunction

Signaling through toll-like receptor 4 (TLR4) plays an obligate role in burn-related myocardial dysfunction. We hypothesized that signaling through CD14, a cellular receptor for endotoxin that lacks a transmembrane domain but is coupled to TLR4, also plays a role in postburn myocardial inflammation and dysfunction. Burn covering 40% total body surface area (or sham burn for controls) was produced in wild-type (WT) and CD14 knockout (KO) as well as vehicle-treated and geldanamycin-treated WT mice (1 microg/g body weight) to inhibit CD14 signaling. Groups included (1) WT shams, (2) CD14 KO sham, (3) WT burns, (4) CD14 KO burns, (5) vehicle-treated WT shams, (6) geldanamycin-treated WT shams, (7) vehicle-treated WT burns, and (8) geldanamycin-treated WT burns. Twenty-four hours after burn, cardiac function (Langendorff) and cardiomyocyte secretion of inflammatory cytokines TNF-alpha, IL-1 beta, and IL-6 (in pg/mL; 5 x 10(4) myocytes) were studied in all groups. Relative to sham WT controls, burn trauma in increased cardiac myocyte secretion of inflammatory cytokines (TNF-alpha, IL-1 beta, and IL-6 rose from 59 +/- 10 to 171 +/- 8; 6 +/- 0.2 to 78 +/- 1; and 88 +/- 3 to 170 +/- 12 pg/mL, respectively; P < 0.05) and produced robust cardiac contractile dysfunction (left ventricular pressure and +dP/dt fell from 105 +/- 4 to 73 +/- 5 mmHg and 2,400 +/- 73 to 1,803 +/- 90 mmHg/s; P < 0.05). Inability to signal through the CD14/TLR4 pathway (induced by CD14/KO or inhibition of CD14 expression by administration of geldanamycin) attenuated TNF-alpha, IL-1 beta, and IL-6 production in response to burn injury and improved postburn myocardial contractile function. Our data suggest that signaling through the CD14 pathway plays an obligate role in cardiac inflammation/dysfunction which occurs after major burn injury.

Influence of C-159T SNP of the CD14 gene promoter on lung function in smokers

CD14, a co-receptor for endotoxin, plays a significant role in regulating the inflammatory response to this agent. The C-159T single nucleotide polymorphism (SNP) in the CD14 gene promoter is an important regulator of CD14 expression, with TT homozygotes having increased expression of CD14. This SNP has been linked to pathogenesis of asthma and with cardiovascular diseases in smokers. We hypothesize that CD14 also plays a role in the pathophysiology of COPD in smokers who are exposed to endotoxin contained in cigarette smoke as well as endotoxin derived from Gram-negative microbes colonizing their airways. To assess the effect of the C-159T SNP of the CD14 gene promoter on lung function, we recruited 246 smokers 40 years of age or older with a range of 10-156 pack-year smoking exposures. The TT genotype was associated with lower lung function in smokers with a moderate smoking history. However, the CC genotype was associated with decreased lung function in heavy smokers (>56 pack years). The effect of CC genotype on severity of COPD is analogous with the effect of this genotype in risk for asthma. CD14 may be a factor in the pathophysiology of COPD, as it is in asthma and smoking-related cardiovascular diseases.

Effects of wheat germ agglutinin on human gastrointestinal epithelium: insights from an experimental model of immune/epithelial cell interaction

Wheat germ agglutinin (WGA) is a plant protein that binds specifically to sugars expressed, among many others, by human gastrointestinal epithelial and immune cells. WGA is a toxic compound and an anti-nutritional factor, but recent works have shown that it may have potential as an anti-tumor drug and as a carrier for oral drugs. To quantitate the toxicity threshold for WGA on normal epithelial cells we previously investigated the effects of the lectin on differentiated Caco2 cells, and showed that in the micromolar range of concentrations WGA could alter the integrity of the epithelium layer and increase its permeability to both mannitol and dextran. WGA was shown to be uptaken by Caco2 cells and only approximately 0.1% molecules were observed to cross the epithelium layer by transcytosis. Here we show that at nanomolar concentrations WGA is unexpectedly bioactive on immune cells. The supernatants of WGA-stimulated peripheral blood mononuclear cells (PBMC) can alter the integrity of the epithelium layer when administered to the basolateral side of differentiated Caco2 cells and the effects can be partially inhibited by monoclonal antibodies against IL1, IL6 and IL8. At nanomolar concentrations WGA stimulates the synthesis of pro-inflammatory cytokines and thus the biological activity of WGA should be reconsidered by taking into account the effects of WGA on the immune system at the gastrointestinal interface. These results shed new light onto the molecular mechanisms underlying the onset of gastrointestinal disorders observed in vivo upon dietary intake of wheat-based foods.

The additive contribution from inflammatory genetic markers on the severity of cardiovascular disease

Inflammation plays a key role in the development of atherosclerosis. Genetic differences in molecules related to inflammation have therefore been linked to the susceptibility for and severity of atherosclerosis. We hypothesized that the additive contribution from different genes of importance for inflammation would enhance the severity of cardiovascular disease. Blood samples were collected from 230 adults admitted for elective coronary angiography. A total of 130 patients had significant (>50%) stenosis in at least one main coronary artery branch and 100 had not. Six polymorphisms in five different genes were analysed: myeloperoxidase (MPO) -129G/A and -463G/A, toll-like receptor 4 (TLR4) Asp299Gly, interleukin-6 (IL6) -174G/C, surfactant protein D (SFTPD) Met11Thr and regulated upon normal T-cell expressed and secreted (CCL5) -403G/A. The IL6 polymorphism was significantly associated (P = 0.017) to angiographic significant coronary artery disease, and this relation remained after adjustment for age, gender, smoking and hypercholesterolaemia (P = 0.007). The TLR4 (P = 0.050) and SFTPD (P = 0.058) polymorphisms were also associated with the presence of coronary stenosis in univariate but not in multivariate analyses. For MPO and CCL5 no associations were found. There was a significant linear association between the number of high-risk gene variants (IL6-174CC, SFTPD 11CC and TLR4 299AA) and the proportion of patients with coronary artery disease (P < 0.0005). Inherited factors related to inflammation may increase susceptibility for severe coronary artery disease. Furthermore, the additive contribution from different inflammatory genetic markers strongly enhances the individual severity of cardiovascular disease.

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.

Myocardial infarction after meningococcal infection: a potential inflammatory link or a challenging puzzle?

There is evidence that systemic inflammatory response and infectious diseases are associated with an increased risk of vascular events such as stroke and myocardial infarction in humans. However, the potential triggering effect of infectious diseases in carciovascular phenomena is typically underreported, overlooked and unexplored. The remarkable discovery of the link between cytokine networks and the pathophysiology of infectious diseases, together with studies of the CD14+ Toll-like receptor 4 (TLR4), has increased our knowledge of the inflammatory cascade within the vascular compartment as well as of coronary artery disease. In addition, meningococcal sepsis can trigger an important host inflammatory response characterized by systemic production of cytokines and chemokines, as well as activation of complement and nitric oxide pathways. However, the exact mechanism involved and the multiple pathogenic links by which infection influences acute cardiovascular events have not been explored, presenting a challenging puzzle for researchers. Determining cytokine concentrations could prove to be a valuable tool in evaluating the pathophysiology of myocardial infarction during infectious processes. The knowledge gained could guide the development of new strategies for reducing the occurrence of adverse cardiovascular events.

Second hit post burn increased proximal gut mucosa epithelial cells damage

Secondary infections after burn are common and are a major contributor to morbidity and mortality. We previously showed that burn disrupted proximal gut mucosal homeostasis through increased epithelial cell apoptosis. In the present study, we sought to determine whether proximal gut mucosal disruption is additively affected by secondary endotoxemia after a severe burn. C57BL/6 mice received 30% total body surface area full-thickness scald burns and were randomized to receive saline or LPS 1 mg/kg body weight given intraperitoneally 72 h after burn. Proximal small bowel was harvested 12 h after LPS injection. Mucosal height and epithelial cell number were assessed on hematoxylin-eosin sections, intestinal epithelial cell apoptosis was identified by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and cell proliferation by immunohistochemical staining for proliferating cell nuclear antigen. Results showed that proximal gut mucosa impairment occurred 12 h after injury, including significantly decreased proximal gut wet weight, gut mucosal height, and epithelial cell number associated with increased proximal gut epithelial apoptosis (P < 0.05). This impairment diminished 72 h after burn. Second-hit endotoxemia caused additional proximal gut mucosa damage with decreased proximal gut weight, cell number, and mucosal height (P < 0.05) and significantly increased small intestinal epithelial apoptosis and mucosal atrophy, even after the first event, indicating a second detrimental effect of endotoxemia after the initial injury.

Toll-like receptors, transduction-effector pathways, and disease diversity: evidence of an immunobiological paradigm explaining all human illness?

Membrane-bound Toll-like receptors (TLRs) are frontline guardians in the mammalian innate immune system. They primarily function to recognize pathogen-associated molecular patterns (PAMPs) of invading microorganisms and on activation mount rapid, nonspecific innate responses and trigger sequential delayed specific adaptive cellular responses, which are mediated by complex signal transduction pathways involving adaptor molecules, costimulatory ligands and receptors, kinases, transcription factors, and modulated gene expression. Increasing evidence of multiple functionality and diversity suggests TLRs play critical roles in noninfective medical conditions such as cardiovascular, gastrointestinal, neurologic, musculoskeletal, obstetric, renal, liver, and dermatologic diseases, allergy, autoimmunity, and tissue regeneration. The significance of TLR heterogeneity underscores the possibility for establishing a universal immunobiological model to explain all human disease. Novel immunomodulatory therapies targeting specific or multiple TLRs may in the future offer new tools to combat or eradicate pathogenesis potentially transforming the landscape of current medical treatments.

Identifying the susceptibility genes for coronary artery disease: from hyperbole through doubt to cautious optimism

The genetic basis of coronary artery disease (CAD) is complex, and the fact that an alarmingly high proportion of reported associations between genetic variants and CAD are not replicated has generated uncertainty as to whether molecular genetics is ever going to deliver on the promises delivered in the late 1990s. However, during 2007, the first generation of large-scale genome-wide association studies using high-density, single nucleotide polymorphism genotyping arrays have revealed genetic variants that are robustly associated with CAD and CAD-related traits such as type 2 diabetes and obesity. In particular, a robust susceptibility locus for CAD has been identified on chromosome 9p21. Also, evidence has been obtained that multiple rare alleles with fairly strong phenotypic effects may contribute to the genetic heritability of CAD, in addition to common variants with a modest impact on risk. Furthermore, new mechanistic connections have been discovered between different common complex diseases including CAD. This review focuses on the challenges and recent advances of molecular genetics in dissecting the molecular pathophysiology of atherothrombosis and defining novel targets for treatment.

Human adipose tissue stromal vascular fraction cells differentiate depending on distinct types of media

OBJECTIVES

Angiogenesis, the process of formation of blood vessels, is essential for many physiological as well as pathological processes. It has been shown that human adipose tissue contains a population of non-characterized cells, called stromal-vascular fraction (SVF) cells, which are able to differentiate into several lineages. The aim of this study was to determine conditions for promoting differentiation of human adipose tissue progenitors towards endothelial cells, as well as to show that SVF cells cooperate with differentiated endothelium in capillary network formation.

MATERIALS AND METHODS

Stromal vascular fraction cells were isolated according to modified Hauner's method and after adaptation they were cultured in pro-angiogenic or pro-adipogenic medium. Cells were characterized by presence of surface antigens by flow cytometry, and by expression of genes characteristic for endothelial cells or for adipocytes, quantitative real-time polymerase chain reaction. A number of tests were performed to verify their differentiation.

RESULTS

Differentiation of human SVF cells towards endothelium was stimulated by the presence of serum and absence of adipogenic factors, documented by the pattern of gene expression as well as different functional in vitro assays. SVF cells were found to work together with human umbilical vein endothelial cells to form capillary networks.

CONCLUSIONS

Here, we show that differentiation of SVF cells to endothelial cells or adipocyte-like cells depended on the medium used. Our work provides a clear model for analysing the differentiation capacity of SVF cells.

Discovering susceptibility genes for asthma and allergy

Asthma and asthma-related traits are complex diseases with strong genetic and environmental components. Rapid progress in asthma genetics has led to the identification of several candidate genes that are associated with asthma-related traits. Typically the phenotypic impact of each of these genes, including the ones most often replicated in association studies, is mild, but larger effects may occur when multiple variants synergize within a permissive environmental context. Despite the achievements made in asthma genetics formidable challenges remain. The development of novel, powerful tools for gene discovery, and a closer integration of genetics and biology, should help to overcome these challenges.

Synergistic contribution of CD14 and HLA loci in the susceptibility to Buerger disease

Buerger disease (BD) is an occulusive vascular disease of unknown etiology. Although cigarette smoking is a well-known risk factor of BD, genetic factors may also play a role in the etiology. Because chronic bacterial infection such as oral periodontitis is suggested to be involved in the pathogenesis of BD, gene polymorphisms involved in the infectious immunity might be associated with BD as the genetic factor(s). We have previously reported that HLA-DRB1*1501 and B54 was associated with BD in Japanese. In this study, polymorphisms in HLA-DPB1, DRB1 and B were analyzed in 131 Japanese BD patients and 227 healthy controls. In addition, we investigated a functional promoter polymorphism, -260 C > T, of CD14 that is a main receptor of bacterial lipopolysaccharide. It was found that the frequencies of CD14 TT genotype [37.4 vs. 24.2%, P = 0.008 OR = 1.87, 95% confidence interval (CI); 1.18, 2.97], DRB1*1501 (34.4 vs. 13.2%, P (c) = 4.4 x 10(-5), OR = 3.44, 95%CI; 2.06, 5.73) and DPB1*0501 (79.4 vs. 55.1%, P (c) = 4.7 x 10(-5), OR = 3.14, 95%CI; 1.93, 5.11) were significantly higher in the patients than in the controls, demonstrating that at least three genetic markers were associated with BD. Stratification analyses of these associated markers suggested synergistic roles of the genetic factors. Odds ratios ranged from 4.72 to 12.57 in individuals carrying any two of these three markers. These findings suggested that the susceptibility to BD was in part controlled by genes involved in the innate and adaptive immunity.

Genetics of inflammation in age-related atherosclerosis: its relevance to pharmacogenomics

In response to tissue injury elicited by trauma or infection, the inflammatory response, as a complex network of molecular and cellular interactions, sets an answer directed to facilitate a return to physiological homeostasis and tissue repair. The role of the genetic background and the subsequent predisposition toward the extent of the inflammatory response is determined by gene variability encoding endogenous mediators involved in the inflammatory pathway. Due to its clinical relevance, the genetics of inflammation in aging will be studied using an inflammatory disease like atherosclerosis as an example. Several studies have reported a significant difference in distribution, between patients and controls, of genes involved in inflammation. So, the proinflammatory alleles are underrepresented in control subjects and overrepresented in patients affected by atherosclerosis. These studies will allow building a risk profile that potentially enables the early identification of individuals susceptible to disease and the possible design or use of drug at the right dose for a desired effect, that is, a pharmacogenomic approach for this disease.

Age-related inflammatory diseases: role of genetics and gender in the pathophysiology of Alzheimer's disease

Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease which in Western societies mainly accounts for clinical dementia. A high proportion of women are affected by this disease, especially at a very advanced age, which might to a large extent be associated with the fact that women live longer. However, some studies suggest that incidence rates may be really increased in women. For this reason the influence of estrogens on the brain and the decrease of it during menopause are of special interest. After menopause, circulating levels of estrogens markedly decline, influencing several brain processes predicted to influence AD risk. The control of estrogens on oxidative stress, inflammation, and the cerebral vasculature might also be expected to increase AD risk. During the Women's Health Initiative Memory Study--a randomized, placebo-controlled trial of women 65-79 years of age--oral estrogen plus progestin was seen to double the rate of developing dementia, with risk appearing soon after the treatment was initiated. On the basis of current evidence, hormone therapy (HT) is thus not indicated for the prevention of AD. Inflammation clearly occurs in pathologically vulnerable regions of the AD brain and the search for genetic factors influencing the pathogenesis of AD has led to the identification of numerous gene polymorphisms that act as susceptibility modifiers. Accordingly, several reports have indicated that the risk of AD is substantially influenced by several genetic polymorphisms in the promoter region, or other untranslated regions, of genes encoding inflammatory mediators. Here we review several data suggesting that inflammatory genetic variation may contribute to higher AD susceptibility in women too. All together this information may represent the basis both for future recognition of individuals at risk as well as for a pharmacogenomic approach in achieving drug responsiveness.

Polymorphisms of pro-inflammatory genes and Alzheimer's disease risk: A pharmacogenomic approach

Clinically and pathologically Alzheimer's disease (AD) represents a sequential progressive neurodegenerative disorder. AD is etiologically heterogeneous and accounts for a majority of dementia in western societies. Inflammation clearly occurs in pathologically vulnerable regions of the AD brain and the search for genetic factors influencing the pathogenesis of AD has lead to the identification of numerous gene polymorphisms that might act as susceptibility modifiers. Accordingly, several reports have indicated that the risk of AD is substantially influenced by several genetic polymorphisms in the promoter region, or other untranslated regions, of genes encoding inflammatory mediators, although not all the studies were replied. Here, we review several data suggesting that inflammatory genetic variation may contribute to AD susceptibility. All together this information may represent the basis both for future recognition of individuals at risk and for the pharmacogenomic driving of drug responsiveness.

Inflammatory networks in ageing, age-related diseases and longevity

Inflammation is considered a response set by the tissues in response to injury elicited by trauma or infection. It is a complex network of molecular and cellular interactions that facilitates a return to physiological homeostasis and tissue repair. The individual response against infection and trauma is also determined by gene variability. Ageing is accompanied by chronic low-grade inflammation state clearly showed by 2-4-fold increase in serum levels of inflammatory mediators. A wide range of factors has been claimed to contribute to this state; however, the most important role seems to be played by the chronic antigenic stress, which affects immune system thorough out life with a progressive activation of macrophages and related cells. This pro-inflammatory status, interacting with the genetic background, potentially triggers the onset of age-related inflammatory diseases as atherosclerosis. Thus, the analysis of polymorphisms of the genes that are key nodes of the natural immunity response might clarify the patho-physiology of age-related inflammatory diseases as atherosclerosis. On the other hand, centenarians are characterized by marked delay or escape from age-associated diseases that, on average, cause mortality at earlier ages. In addition, centenarian offspring have increased likelihood of surviving to 100 years and show a reduced prevalence of age-associated diseases, as cardiovascular disease (CVD) and less prevalence of cardiovascular risk factors. So, genes involved in CVD may play an opposite role in human longevity. Thus, the model of centenarians can be used to understand the role of these genes in successful and unsuccessful ageing. Accordingly, we report the results of several studies in which the frequencies of pro-inflammatory alleles were significantly higher in patients affected by infarction and lower in centenarians whereas age-related controls displayed intermediate values. These findings point to a strong relationship between the genetics of inflammation, successful ageing and the control of cardiovascular disease at least in men, in which these studies were performed. These data are also briefly discussed in the light of antagonistic pleiotropy theory and in order to pursuit a pharmacogenomics approach.

Polymorphisms within inflammatory genes and colorectal cancer

Background

Chronic inflammation is a risk factor for colorectal cancer and polymorphisms in the inflammatory genes could modulate the levels of inflammation. We have investigated ten single nucleotide polymorphisms (SNPs) in the following inflammation-related genes: TLR4 (Asp299Gly), CD14 (-260 T>C), MCP1 (-2518 A>G), IL12A (+7506 A>T, +8707 A>G, +9177 T>A, +9508 G>A), NOS2A (+524T>C), TNF (-857C>T), and PTGS1 (V444I) in 377 colorectal (CRC) cancer cases and 326 controls from Barcelona (Spain).

Results

There was no statistically significant association between the SNPs investigated and colorectal cancer risk.

Conclusion

The lack of association may show that the inflammatory genes selected for this study are not involved in the carcinogenic process of colorectum. Alternatively, the negative results may derive from no particular biological effect of the analysed polymorphisms in relation to CRC. Otherwise, the eventual biological effect is so little to go undetected, unless analysing a much larger sample size.

Inflammation, longevity, and cardiovascular diseases: role of polymorphisms of TLR4

The total burden of infection at various sites may affect the progression of atherosclerosis, the risk being modulated by host genotype. The role of lipopolysaccaride receptor TLR4 is paradigmatic. It initiates the innate immune response against gram-negative bacteria; and TLR4 polymorphisms, as ASP299GLY, suggested to attenuate receptor signaling, have been described. We demonstrated that TLR4 ASP299GLY polymorphism shows a significantly lower frequency in patients affected by myocardial infarction compared to controls, whereas centenarians show a higher frequency. Thus, people genetically predisposed to developing weak inflammatory activity, seem to have fewer chances of developing cardiovascular diseases (CVD) and, subsequently, live longer if they do not become affected by serious infectious diseases. These results are in agreement with our other data demonstrating how genetic background may exert the opposite effect with respect to inflammatory components in CVD and longevity. In the present report, to validate this hypothesis, the levels of interleukin (IL)-6, a pro-inflammatory cytokine involved in atherosclerosis and longevity, were determined by an enzyme-linked immuno-sorbent assay (ELISA) in supernatants from a whole blood assay after stimulation with subliminal doses of lipopolysaccaride (LPS) from Escherichia coli (E. coli). The samples, genotyped for the ASP299GLY polymorphism, were challenged with LPS for 4, 24, and 48 h. What we found was that Il-6 values were significantly lower in carriers bearing TLR4 mutation. Therefore, the pathogen burden, by interacting with host genotype, determines the type and intensity of the immune-inflammatory responses accountable for pro-inflammatory status, CVD, and unsuccessful aging. On the other hand, our present data seem to explain the inconclusive results obtained in case-control studies taking into account the role of functional IL-6 polymorphisms in successful and unsuccessful aging. In fact, IL6 levels seem to depend, in addition, on IL-6 polymorphisms and on innate immunity gene polymorphisms as well.

An explanation for the paradoxical induction and suppression of an acute phase response by ethanol

Binge ethanol (EtOH) consumption suppresses inflammatory responses and resistance to infection, but paradoxically it is associated with increased levels of acute phase proteins (which are indicators of inflammation) and an increased risk of inflammation-mediated pathologies such as cardiovascular disease and cirrhosis of the liver. The latter effect may be mediated by increased translocation of bacteria leading to activation of toll-like receptor 4 (TLR4). In this study, the dose-response and time course of the effects of EtOH alone or EtOH in conjunction with a TLR4 agonist (lipopolysaccharide [LPS]) were evaluated in mice. EtOH alone at a dosage of 6 g/kg induced an acute phase response (as indicated by enzyme-linked immunosorbent assay for serum amyloid A and serum amyloid P) that was maximal 24 h after dosing. Lower dosages of EtOH did not have this effect but did suppress the acute phase response to LPS and the production of interleukin-6 up to 3 h after dosing. EtOH at 6 g/kg did not induce an acute phase response in C3H/HeJ (TLR4 mutant) mice, indicating that this response is mediated through TLR4. These results provide a resolution for the apparently paradoxical pro- and anti-inflammatory actions of EtOH with regard to acute phase responses.

Opposite Role of Pro-Inflammatory Alleles in Acute Myocardial Infarction and Longevity: Results of Studies Performed in a Sicilian Population

The major trait characterizing offspring in centenarians is a reduction in the prevalence of cardiovascular disease. Because a pro-inflammatory genotype seems to contribute significantly to the risk of coronary heart disease, alleles associated with disease susceptibility would not be included in the genetic background favoring longevity, as suggested by our previous studies on inflammatory cytokines. To confirm whether genotypes of inflammatory molecules play an opposite role in atherosclerosis and longevity, we are studying the role of other proinflammatory alleles, such as pyrin and CCR5, in acute myocardial infarction and longevity. The results support the hypothesis that the genetic background favoring cardiovascular diseases is detrimental to longevity. In addition, they suggest that the centenarian genetic background may be useful for investigating genetic key components of age-associated diseases that are characterized by a multifactorial etiology.

Polymorphism at position +896 of the toll-like receptor 4 gene interferes with rapid response to treatment in rheumatoid arthritis

The aim of this study was to determine whether the +896 A-->G substitution of the Toll-like receptor 4 (TLR4) gene, causing the Asp299-->Gly change in the extracellular domain of TLR4, influences treatment response in recent-onset rheumatoid arthritis. 169 patients with rheumatoid arthritis were genotyped from the Finnish Rheumatoid Arthritis Combination Therapy trial, in which they were treated either with only one disease-modifying antirheumatic drug (DMARD) with or without prednisolone (single group), or with three DMARDs and prednisolone (combination group). Patients homozygotic for the wild-type +896A allele were compared with those having the polymorphic G allele in terms of early clinical response (at 6 months) by the 28-joint Disease Activity Score (DAS28). 1 of 20 (5%; (95% (confidence interval (CI) 1 to 5)) patients of the single group with TLR4 +896AG or GG and 29 of 67 (43%; (95% CI 31 to 56)) patients with AA were in remission (p = 0.001). DAS28 of the single group with TLR4 +896AG or GG was higher than with AA (p = 0.019). In the combination group, remission rates and DAS28 values were comparable between the genotypes. The polymorphic TLR4 +896G allele may impair treatment response to single DMARD treatment in recent-onset rheumatoid arthritis.

Genetic susceptibility to coronary artery disease: from promise to progress

Family history is an important independent risk factor for coronary artery disease (CAD), and identification of susceptibility genes for this common, complex disease is a vital goal. Although there has been considerable success in identifying genetic variants that influence well-known risk factors, such as cholesterol levels, progress in unearthing novel CAD genes has been slow. However, advances are now being made through the application of large-scale, systematic, genome-wide approaches. Recent findings particularly highlight the link between CAD and inflammation and immunity, and highlight the biological insights to be gained from a genetic understanding of the world's biggest killer.

Biology of Longevity: Role of the Innate Immune System

Genetic factors play a relevant role in the attainment of longevity because they are involved in cell maintenance systems, including the immune system. In fact, longevity may be correlated with optimal functioning of clonotypic and natural immunity. The aging of the immune system, known as immunosenescence, is the consequence of the continuous attrition caused by chronic antigenic overload. The antigenic load results in the progressive generation of inflammatory responses involved in age-related diseases. Most of the parameters influencing immunosenescence appear to be under genetic control, and immunosenescence fits with the basic assumptions of evolutionary theories of aging, such as antagonistic pleiotropy. In fact, by neutralizing infectious agents the immune system plays a beneficial role until reproduction and parenting. However, by determining chronic inflammation, it can be detrimental later in life, a period largely unforeseen by evolution. In particular, the data coming from the long-lived male population under study show that genetic polymorphisms responsible for a low inflammatory response might result in an increased chance of long lifespan in an environment with a reduced pathogen burden. Such a modern and healthy environment also permits a lower grade of survivable atherogenic inflammatory response.

Density of Chlamydia pneumoniae is increased in fibrotic and calcified areas of degenerative aortic stenosis

BACKGROUND

The process of aortic degeneration associated with calcified aortic stenosis shares many similarities with coronary artery atherosclerosis. Inflammation and infection are involved in both diseases. Chlamydia pneumoniae has been identified in atherosclerotic plaques. However, the studies about the presence of C. pneumoniae in degenerative aortic stenotic valves are not conclusive.

OBJECTIVE

We investigated whether an association exists between the density of C. pneumoniae and fibrosis or calcification in aortic stenosis.

DESIGN

Autopsy and surgical specimens were divided into 3 groups: Normal, 11 normal autopsy valves Atherosclerosis, 10 autopsy valves from patients with systemic atherosclerosis and no aortic stenosis and Aortic stenosis, 14 surgical specimens of aortic valves replaced due to aortic stenosis.

SETTING

Heart Institute (InCor), University of São Paulo Medical School.

PATIENTS

Aortic valves from patients aged 52+/-16 years, 69+/-9 years, and 71+/-8 years.

INTERVENTION

Specimens were evaluated by immunohistochemical technique (to detect C. pneumoniae antigens), in situ hybridization, and electron microscopy (to quantify the density of C. pneumoniae in the valves).

MEASUREMENTS

The aortic stenosis group was analyzed according to 3 subregions: aortic stenosis-preserved, peripheral preserved regions; aortic stenosis-fibrosis, peri-calcified fibrotic tissue; and aortic stenosis-calcification, calcified nodules.

RESULTS

The median values of C. pneumoniae antigens were 0.09, 0.30, 0.18, 1.33, and 3.3 in groups Normal, Atherosclerosis, Aortic stenosis-preserved, Aortic stenosis-fibrosis, and Aortic stenosis-calcification, respectively. The amount of C. pneumoniae was greater in the Atherosclerosis and Aortic stenosis-calcification groups than in the Normal group (P<0.05). C. pneumoniae was greater in the Aortic stenosis group in the calcified and fibrotic regions than in preserved region (P<0.05).

CONCLUSION

An association was found between the higher density of C. pneumoniae and fibrosis/calcification in stenotic aortic valves.

Single nucleotide polymorphisms of Toll-like receptors and susceptibility to infectious disease

Toll-like receptors (TLRs) play an important part in the innate immune recognition of invading microorganisms, initiating sufficient immune responses. Growing amounts of data suggest that the ability of certain individuals to respond properly to TLR ligands may be impaired by single nucleotide polymorphisms (SNPs) within TLR genes, resulting in an altered susceptibility to, or course of, infectious or inflammatory disease. Most studies have focused on two cosegregating SNPs-Asp299gly and Thr399Ile-within the gene encoding TLR4, the receptor for bacterial lipopolysaccharide. These SNPs are present in approximately 10% of white individuals, and have been found to be positively correlated with several infectious diseases. However, these SNPs seem to protect from atherosclerosis and related diseases, which is reviewed in this article also. Meanwhile, SNPs of genes encoding other TLRs-eg, TLR2, which recognises a wide variety of microbial ligands-have been reported, and preliminary studies indicate an impact on susceptibility to infectious and inflammatory diseases as well. This review summarises and discusses the results obtained, and draws conclusions from these data.