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

Identification of apoB-100 Peptide-Specific CD8+ T Cells in Atherosclerosis

Background

T cells are found in atherosclerotic plaques, with evidence supporting a potential role for CD8+ T cells in atherogenesis. Prior studies provide evidence of low‐density lipoprotein and apoB‐100 reactive T cells, yet specific epitopes relevant to the disease remain to be defined. The current study was undertaken to identify and characterize endogenous, antigen‐specific CD8+ T cells in atherosclerosis.

Methods and Results

A peptide fragment of apoB‐100 that tested positive for binding to the mouse MHC‐I allele H2K^b was used to generate a fluorescent‐labeled H2K^b pentamer and tested in apoE^−/− mice. H2K^b pentamer(+)CD8+ T cells were higher in apoE^−/− mice fed an atherogenic diet compared with those fed a normal chow. H2K^b pentamer (+)CD8+ T cells in atherogenic diet–fed mice had significantly increased effector memory phenotype with a shift in Vβ profile. H2K^b pentamer blocked lytic activity of CD8+ T cells from atherogenic diet–fed mice. Immunization of age‐matched apoE^−/− mice with the apoB‐100 peptide altered the immune‐dominant epitope of CD8+ T cells and reduced atherosclerosis.

Conclusions

Our study provides evidence of a self‐reactive, antigen‐specific CD8+ T‐cell population in apoE^−/− mice. Immune modulation using the peptide antigen reduced atherosclerosis in apoE^−/− mice.

Recent advances on CD4+ T cells in atherosclerosis and its implications for therapy

Atherosclerosis is an arterial inflammatory disease and the primary cause of cardiovascular disease. T helper (Th) cells are an important part in atherosclerotic plaque as they can be either disease promoting or protective. A body of evidence points to a pro-atherosclerotic role of Th1 cells, whereas the role of Th2, Th17 and iNKT cells seems more complex and dependent on surrounding factors, including the developmental stage of the disease. Opposed to Th1 cells, there is convincing support for an anti-atherogenic role of Tregs. Recent data identify the plasticity of Th cells as an important challenge in understanding the functional role of different Th cell subsets in atherosclerosis. Much of the knowledge of Th cell function in atherosclerosis is based on findings from experimental models and translating this into human disease is challenging. Targeting Th cells and/or their specific cytokines represents an attractive option for future therapy against atherosclerosis, although the benefits and the risk of modulation of Th cells with these novel drug targets must first be carefully assessed.

Obesity-Induced Metabolic Stress Leads to Biased Effector Memory CD4+ T Cell Differentiation via PI3K p110δ-Akt-Mediated Signals

Low-grade systemic inflammation associated to obesity leads to cardiovascular complications, caused partly by infiltration of adipose and vascular tissue by effector T cells. The signals leading to T cell differentiation and tissue infiltration during obesity are poorly understood. We tested whether saturated fatty acid-induced metabolic stress affects differentiation and trafficking patterns of CD4+ T cells. Memory CD4+ T cells primed in high-fat diet-fed donors preferentially migrated to non-lymphoid, inflammatory sites, independent of the metabolic status of the hosts. This was due to biased CD4+ T cell differentiation into CD44hi-CCR7lo-CD62Llo-CXCR3+-LFA1+ effector memory-like T cells upon priming in high-fat diet-fed animals. Similar phenotype was observed in obese subjects in a cohort of free-living people. This developmental bias was independent of any crosstalk between CD4+ T cells and dendritic cells and was mediated via direct exposure of CD4+ T cells to palmitate, leading to increased activation of a PI3K p110δ-Akt-dependent pathway upon priming.

Dysfunction of the thymus in mice with hypertension

The aim of this study was to evaluate thymus function in mice with hypertension. A total of 60 C57BL/6J mice were randomized into control, sham surgery and two-kidney, one-clip groups (n=20 in each). At 4 or 8 weeks after surgery, mice were sacrificed, and blood, spleens, kidneys and thymuses were harvested. The results of reverse transcription-quantitative polymerase chain reaction analysis revealed that the mRNA levels of Forkhead box protein N1 (Foxn1) and autoimmune regulator (AIRE) in the thymus tissue of mice from the HTN group were significantly lower than those from the control group at 4 and 8 weeks (P<0.05). Foxn1 and AIRE expression was also reduced in the sham surgery group at 4 weeks after surgery, but had recovered 4 weeks later. Similar results were observed for the expression of signal-joint T cell receptor excision circles and the percentages of T cell subsets. The present study indicates that impaired thymus function is associated with hypertension in mice, which suggests that thymus function may be a novel target for the treatment of patients with hypertension.

Readapting the adaptive immune response - therapeutic strategies for atherosclerosis

Cardiovascular diseases remain a major global health issue, with the development of atherosclerosis as a major underlying cause. Our treatment of cardiovascular disease has improved greatly over the past three decades, but much remains to be done reduce disease burden. Current priorities include reducing atherosclerosis advancement to clinically significant stages and preventing plaque rupture or erosion. Inflammation and involvement of the adaptive immune system influences all these aspects and therefore is one focus for future therapeutic development. The atherosclerotic vascular wall is now recognized to be invaded from both sides (arterial lumen and adventitia), for better or worse, by the adaptive immune system. Atherosclerosis is also affected at several stages by adaptive immune responses, overall providing many opportunities to target these responses and to reduce disease progression. Protective influences that may be defective in diseased individuals include humoral responses to modified LDL and regulatory T cell responses. There are many strategies in development to boost these pathways in humans, including vaccine-based therapies. The effects of various existing adaptive immune targeting therapies, such as blocking critical co-stimulatory pathways or B cell depletion, on cardiovascular disease are beginning to emerge with important consequences for both autoimmune disease patients and the potential for wider use of such therapies. Entering the translation phase for adaptive immune targeting therapies is an exciting and promising prospect.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Methylation of the FOXP3 upstream enhancer as a clinical indicator of defective regulatory T cells in patients with acute coronary syndrome

Atherosclerosis is an immune-mediated inflammatory process, which acts as the main cause of acute coronary syndrome (ACS). Regulatory CD4+CD25+FOXP3+T cells (Tregs) are thought to play a major role in inhibiting the formation and progression of atherosclerosis. However, the exact role played by Tregs in the pathogenesis of ACS is yet remained unclear. FOXP3 is a key regulator of Treg formation and function. Demethylation at the CpG-rich island of FOXP3 upstream enhancers can alter FOXP3 expression, and may affect Treg function during the development of ACS. This study investigated the immunosuppressive function and methylation status of a FOXP3 upstream enhancer in Tregs in ACS patients. Notably, Tregs from ACS patients exhibited a significantly lower immunosuppressive effect on Teffs. Furthermore, the methylation status of the FOXP3 upstream enhancer was significantly increased in ACS patients. Consistent with these observations, Tregs originated from ACS patients manifested significantly lower levels of FOXP3 mRNA. The immunosuppressive effect of Tregs on Teffs was compromised in ACS patients. Together, our data suggest that examination of the methylation status of the FOXP3 upstream enhancer might be a novel approach to diagnose ACS and to differentiate ACS subtypes.

Circulating CD14+ and CD14highCD16- classical monocytes are reduced in patients with signs of plaque neovascularization in the carotid artery

BACKGROUND AND AIMS

Monocytes are known to play a key role in the initiation and progression of atherosclerosis and contribute to plaque destabilization through the generation of signals that promote inflammation and neoangiogenesis. In humans, studies investigating the features of circulating monocytes in advanced atherosclerotic lesions are lacking.

METHODS

Patients (mean age 69 years, 56% males) with intermediate asymptomatic carotid stenosis (40-70% in diameter) were evaluated for maximal stenosis in common carotid artery, carotid bulb and internal carotid artery, overall disease burden as estimated with total plaque area (TPA), greyscale and neovascularization in 244 advanced carotid plaques. Absolute counts of circulating CD14+ monocytes, of classical (CD14^highCD16-), intermediate (CD14^highCD16+) and non-classical (CD14^lowCD16+) monocytes and HLA-DR+ median fluorescence intensity for each subset were evaluated with flow cytometry.

RESULTS

No correlation was found between monocytes and overall atherosclerotic burden, nor with high sensitivity C-reactive protein (hsCRP) or interleukin-6 (IL-6). In contrast, plaque signs of neovascularization were associated with significantly lower counts of circulating CD14+ monocytes (297 versus 350 cells/mm³, p = 0.039) and of classical monocytes (255 versus 310 cells/mm³, p = 0.029).

CONCLUSIONS

Neovascularized atherosclerotic lesions selectively associate with lower blood levels of CD14+ and CD14^highCD16- monocytes independently of systemic inflammatory activity, as indicated by normal hsCRP levels. Whether the reduction of circulating CD14+ and CD14^highCD16- monocytes is due to a potential redistribution of these cell types into active lesions remains to be explored.

Innate Effector-Memory T-Cell Activation Regulates Post-Thrombotic Vein Wall Inflammation and Thrombus Resolution

RATIONALE

Immune cells play an important role during the generation and resolution of thrombosis. T cells are powerful regulators of immune and nonimmune cell function, however, their role in sterile inflammation in venous thrombosis has not been systematically examined.

OBJECTIVE

This study investigated the recruitment, activation, and inflammatory activity of T cells in deep vein thrombosis and its consequences for venous thrombus resolution.

METHODS AND RESULTS

CD4⁺ and CD8⁺ T cells infiltrate the thrombus and vein wall rapidly on deep vein thrombosis induction and remain in the tissue throughout the thrombus resolution. In the vein wall, recruited T cells largely consist of effector-memory T (T_EM) cells. Using T-cell receptor transgenic reporter mice, we demonstrate that deep vein thrombosis-recruited T_EM receive an immediate antigen-independent activation and produce IFN-γ (interferon) in situ. Mapping inflammatory conditions in the thrombotic vein, we identify a set of deep vein thrombosis upregulated cytokines and chemokines that synergize to induce antigen-independent IFN-γ production in CD4⁺ and CD8⁺ T_EM cells. Reducing the number of T_EM cells through a depletion recovery procedure, we show that intravenous T_EM activation determines neutrophil and monocyte recruitment and delays thrombus neovascularization and resolution. Examining T-cell recruitment in human venous stasis, we show that superficial varicose veins preferentially contain activated memory T cells.

CONCLUSIONS

T_EM orchestrate the inflammatory response in venous thrombosis affecting thrombus resolution.

Cytomegalovirus-Productive Infection Is Associated With Acute Coronary Syndrome

BACKGROUND

Although an association between human herpesvirus (HHV) infection and atherosclerosis has been suggested, the data supporting such an association are controversial and, in most cases, are based on serological evidence or on the presence of cell-associated HHV DNA, which do not report about actual viral replication. We quantified the DNA of all 8 types of HHVs in plasma, in which their presence is evidence of viral replication.

METHODS AND RESULTS

Using quantitative real-time polymerase chain reaction, we evaluated the presence of HHV DNA in blood samples obtained at the time of hospitalization from 71 patients with acute coronary syndrome, 26 patients with stable coronary artery disease, and 53 healthy volunteers and in atherosclerotic plaques of 22 patients with peripheral artery disease who underwent endarterectomy. HHV-5 (cytomegalovirus [CMV]) was the only HHV with a level that was higher in acute coronary syndrome patients than in the control group and that correlated with the level of high-sensitivity C-reactive protein. The numbers of effector memory T cells positively correlated with the numbers of CMV genome copies in carotid arteries plaques, whereas the numbers of central memory T cells negatively correlated with CMV copy numbers.

CONCLUSIONS

Of all HHV levels, only CMV was higher in patients with stable coronary artery disease and acute coronary syndrome than in the healthy group, and its load correlated with the level of high-sensitivity C-reactive protein. The level of CMV in atherosclerotic plaques correlated with the state of immunoactivation of lymphocytes in plaques, suggesting that the reactivation of CMV may contribute to the immune activation associated with the progression of atherosclerosis.

Psychoneuroimmunological aspects of cardiovascular diseases: a preliminary report

Aim of the study

Due to their prevalence and negative social effects, cardiovascular diseases belong to a group of civilization diseases. Previous research suggests comorbidity of heart diseases, mood disorders and impaired cognitive functioning. The aim of this study was to evaluate the psychoneuroimmunological aspects of functioning in patients diagnosed with cardiovascular diseases.

Material and methods

Ten persons, mean age 48.2 years old, diagnosed with primary hypertension, were studied. All of them were treated with beta blockers and ACE inhibitors with unsuccessful therapeutic effect. This group also included 4 subjects with heart rate disturbances. The control group included 10 clinically healthy volunteers in mean age 46.8. All participants had 24-hour ECG monitoring with Holter method in order to evaluate the autonomic activity with time and frequency domain analysis (heart rate variability). Patients also underwent neuropsychological assessment of quality of life and personality traits (EQ-5D, NEO-PI-R, PSS10, SWLS, MHLC). Quantitative evaluation of immune system parameters included: TCD3, TCD4, CD8, CD16/CD56, CD19, HLA-DR+.

Results

The cardiovascular disease group showed significantly lower time and frequency domain parameters (p < 0.05) except low/high frequency (LF/HF) power ratio. The heart rhythm disorder group demonstrated significant relationships such as: Quality of life with Total Power of HRV and day-time LF/HF ratio, pNN50 and rMSSD – negative correlation.

Conclusions

1. In cardiovascular disease patients, activity of the autonomic nervous system is significantly reduced. 2. Impaired modulation of the autonomic nervous system activity affects mood and decreases quality of life. 3. In patients with heart rhythm disturbances, increased sympathetic nervous system activity affects prolonged tension and the immune response.

Immune-inflammatory responses in atherosclerosis: Role of an adaptive immunity mainly driven by T and B cells

Adaptive immune response plays an important role in atherogenesis. In atherosclerosis, the proinflammatory immune response driven by Th1 is predominant but the anti-inflammatory response mediated mainly by regulatory T cells is also present. The role of Th2 and Th17 cells in atherogenesis is still debated. In the plaque, other T helper cells can be observed such as Th9 and Th22 but is little is known about their impact in atherosclerosis. Heterogeneity of CD4(+) T cell subsets presented in the plaque may suggest for plasticity of T cell that can switch the phenotype dependening on the local microenvironment and activating/blocking stimuli. Effector T cells are able to recognize self-antigens released by necrotic and apoptotic vascular cells and induce a humoral immune reaction. Tth cells resided in the germinal centers help B cells to switch the antibody class to the production of high-affinity antibodies. Humoral immunity is mediated by B cells that release antigen-specific antibodies. A variety of B cell subsets were found in human and murine atherosclerotic plaques. In mice, B1 cells could spontaneously produce atheroprotective natural IgM antibodies. Conventional B2 lymphocytes secrete either proatherogenic IgG, IgA, and IgE or atheroprotective IgG and IgM antibodies reactive with oxidation-specific epitopes on atherosclerosis-associated antigens. A small population of innate response activator (IRA) B cells, which is phenotypically intermediate between B1 and B2 cells, produces IgM but possesses proatherosclerotic properties. Finally, there is a minor subset of splenic regulatory B cells (Bregs) that protect against atherosclerotic inflammation through support of generation of Tregs and production of anti-inflammatory cytokines IL-10 and TGF-β and proapoptotic molecules.

Association of Elevations of Specific T Cell and Monocyte Subpopulations in Rheumatoid Arthritis With Subclinical Coronary Artery Atherosclerosis

OBJECTIVE

Coronary artery disease (CAD) is the leading cause of excess deaths in rheumatoid arthritis (RA). However, identification of features denoting patients with a risk of developing CAD is lacking. The composition of circulating peripheral blood mononuclear cell (PBMC) subsets in RA patients differs markedly from that in healthy controls with regard to the extent of T cell activation, with clonal expansion and differentiation to effector memory status, and presence of inflammatory monocytes. In this study, we sought to evaluate whether elevations in these PBMC subpopulations in RA patients could denote those with an increased risk of subclinical CAD, as determined by the presence of coronary artery calcification (CAC).

METHODS

The study cohort comprised 72 patients with RA who underwent cardiac computed tomography to assess CAC. PBMC subsets were determined by multiparameter flow cytometry. Multivariable logistic regression was used to determine the associations between PBMC subpopulations and the presence of CAC.

RESULTS

Among the 72 patients with RA, 33% had CAC and exhibited significant increases in the levels of circulating CD4 T cell subsets denoting activation and differentiation to the effector memory phenotypes. Analogous increases in the levels of CD8 T cell subsets, as well as in the CD14(high)CD16+ intermediate monocyte subset, were also present in these patients, as compared to those without CAC. The increases in the CD4 and CD8 T cell subsets were highly intercorrelated, whereas the increases in CD14(high)CD16+ monocytes were independent of elevations in the CD4 T cell subsets. After adjustments for relevant confounders, the levels of CD4+CD56+CD57+ T cells and CD14(high)CD16+ monocytes remained associated with the presence of CAC.

CONCLUSION

These findings indicate that PBMC subsets are markers for the presence of CAC and suggest that mechanisms of atherogenesis in RA may operate in part through the elevations in these subsets, raising further questions about the mechanisms underlying the presence of such alterations in cell composition in patients with RA and the potential for shared etiologic pathways between RA and cardiovascular disease.

Regulatory T cells in atherosclerosis: critical immune regulatory function and therapeutic potential

Atherosclerosis is a chronic inflammatory disease that is mediated by innate and adaptive immune responses. The disease is characterized by sub-endothelial accumulation and modification of lipids in the artery wall triggering an inflammatory reaction which promotes lesion progression and eventual plaque rupture, thrombus formation, and the respective clinical sequelae such as myocardial infarction or stroke. During the past decade, T-cell-mediated immune responses, especially control of pro-inflammatory signals by regulatory T cells (Tregs), have increasingly attracted the interest of experimental and clinical researchers. By suppression of T cell proliferation and secretion of anti-inflammatory cytokines, such as interleukin-10 (IL-10) and transforming growth factor-β, Tregs exert their atheroprotective properties. Atherosclerosis-prone, hyperlipidemic mice harbor systemically less Tregs compared to wild-type mice, suggesting an imbalance of immune cells which affects local and systemic inflammatory and potentially metabolic processes leading to atherogenesis. Restoring or increasing Treg frequency and enhancing their suppressive capacity by various modulations may pose a promising approach for treating inflammatory conditions such as cardiovascular diseases. In this review, we briefly summarize the immunological basics of atherosclerosis and introduce the role and contribution of different subsets of T cells. We then discuss experimental data and current knowledge pertaining to Tregs in atherosclerosis and perspectives on manipulating the adaptive immune system to alleviate atherosclerosis and cardiovascular disease.

Reduced T-Cell Thymic Export Reflected by sj-TREC in Patients with Coronary Artery Disease

AIM

Immunologic dysfunction was recently found to be one of the most important mechanisms underlying the initiation and development of atherosclerosis. Thymus involution can contribute to immune disturbance and disequilibrium of T-cell subsets. This study aimed to explore whether recent thymic emigration (RTE) is impaired in patients with coronary artery disease (CAD).

METHODS

Content of signal-joint T cell receptor excision circles (sj-TREC) in T lymphocytes, a molecular marker of RTE, was assessed among CAD patients and age-matched controls. Monochrome multiplex quantitative PCR method was used to assess the samples' telomere length in order to exclude the potential influence of T cell proliferation on the dilution of sj-TREC. Patients were grouped according to Gensini score (GS) (low, GS ＜18; intermediate, GS 18-41; high, GS ＞41). Ordinary logistic regression models were used to determine potential risk factors for CAD and GS tertiles.

RESULTS

Average copy numbers of sj-TREC per 10(6) T lymphocytes among patients with unstable angina, stable angina, and controls were 726±429, 1213±465, and 1795±838, respectively (P＜0.001). However, there was no significant difference in telomere length among groups. Moreover, the content of sj-TREC in the high GS group was most significantly reduced than the low GS group (P＜0.001). Multivariate logistic regression analysis revealed that lower sj-TREC was independently associated with the progression of CAD (OR=0.44, P＜0.001) and higher GS (OR=0.4, P＜0.001).

CONCLUSION

Impaired RTE could be partly responsible for CAD development. Mechanisms may be involved in the disturbance of T lymphocyte compartment and interruption of maintained immune tolerance resulting from thymus involution.

Functional and homeostatic defects of regulatory T cells in patients with coronary artery disease

OBJECTIVE

Regulatory T cells (Tregs) are considered atheroprotective, and low levels have been associated with the acute coronary syndrome (ACS), particularly non-ST elevation (NSTE)-ACS. However, the functional properties as well as homeostasis of Tregs are mainly unknown in coronary artery disease (CAD). Here, we investigated the composition and functional properties of naïve (n) and memory (m)Tregs in patients with NSTE-ACS and in patients 6-12 months post-ACS.

METHODS

Based on the expression of CD25, FOXP3, CD127, CD45RA, CD39 and CTLA-4, Treg subsets were defined by flow cytometry in whole blood or isolated CD4(+) T cells. The functional properties of nTregs and mTregs were examined in terms of proliferative capacity and modulation of cytokine secretion. To understand the potential consequences of Treg defects, we also investigated correlations with lipopolysaccharide (LPS)-induced cytokine secretion and ultrasound-defined carotid atherosclerosis.

RESULTS

Both NSTE-ACS and post-ACS patients exhibited reduced levels of nTregs (P < 0.001) compared with healthy control subjects, but without compensatory increases in mTregs. Both nTregs and mTregs from patients showed significantly lower replicative rates and impaired capacity to modulate T-cell proliferation and secretion of interferon-gamma and IL-10. The Treg defect was also associated with LPS-induced cytokine secretion and increased burden of carotid atherosclerosis.

CONCLUSION

Our results demonstrate a functional and homeostatic Treg defect in patients with NSTE-ACS and also in stabilized patients 6-12 months after ACS. Moreover, this defect was associated with a subclinical proinflammatory and atherogenic state. We believe that the failure to preserve Treg function and homeostasis reflects a need for immune-restoring strategies in CAD.

Age, atherosclerosis and type 2 diabetes reduce human mesenchymal stromal cell-mediated T-cell suppression

To this end human MSCs were isolated from adipose tissue and the MSC:CD4⁺ T-cell suppression was assessed in a co-culture system. In summary, this study demonstrates that advanced age, atherosclerosis and type 2 diabetes mellitus reduce the functional potency of MSCs. Optimizing the criteria for the selection of MSC donors could enhance the results of cell-based therapies.

Peak inflammation in atherosclerosis, primary biliary cirrhosis and autoimmune arthritis is counter-intuitively associated with regulatory T cell enrichment

Regulatory T cells (Treg) influence the development of autoimmunity and their use is increasingly proposed for clinical applications. The well-characterized suppressive potential of Treg frequently leads to the assumption that Treg presence in prevailing numbers is indicative of immunosuppression. We hypothesized that this assumption may be false. We examined models of three different diseases caused by organ-specific autoimmune responses: primary biliary cirrhosis, atherosclerosis and rheumatoid arthritis (RA). We examined indicators of relative abundance of Treg compared to pro-inflammatory T cells, during peak inflammation. In all cases, the results were compatible with a relative enrichment of Treg at the site of inflammation or its most proximal draining lymph node. Conversely, in healthy mice or mice successfully protected from disease via a Treg-mediated mechanism, the data did not suggest that any Treg accumulation was occurring. This counter-intuitive finding may appear to be at odds with the immunosuppressive nature of Treg. Yet extensive previous studies in RA show that an accumulation of Treg occurs at peak inflammation, albeit without resulting in suppression, as the Treg suppressive function is overcome by the cytokine-rich environment. We suggest that this is a ubiquitous feature of autoimmune inflammation. Treg abundance in patient samples is increasingly used as an indicator of a state of immunosuppression. We conclude that this strategy should be revisited as it may potentially be a source of misinterpretation.

T cell senescence and cardiovascular diseases

Age-related changes in the immune system, commonly termed "immunosenescence," contribute to deterioration of the immune response and fundamentally impact the health and survival of elderly individuals. Immunosenescence affects both the innate and adaptive immune systems; however, the most notable changes are in T cell immunity and include thymic involution, the collapse of T cell receptor (TCR) diversity, an imbalance in T cell populations, and the clonal expansion of senescent T cells. Senescent T cells have the ability to produce large quantities of proinflammatory cytokines and cytotoxic mediators; thus, they have been implicated in the pathogenesis of many chronic inflammatory diseases. Recently, an increasing body of evidence has suggested that senescent T cells also have pathogenic potential in cardiovascular diseases, such as hypertension, atherosclerosis, and myocardial infarction, underscoring the detrimental roles of these cells in various chronic inflammatory responses. Given that cardiovascular disease is the number one cause of death worldwide, there is great interest in understanding the contribution of age-related immunological changes to its pathogenesis. In this review, we discuss general features of age-related alterations in T cell immunity and the possible roles of senescent T cells in the pathogenesis of cardiovascular disease.

Fibronectin extra domain A stabilises atherosclerotic plaques in apolipoprotein E and in LDL-receptor-deficient mice

The primary transcript of fibronectin undergoes alternative splicing in the cassette-type EDA and EDB exons and in the IIICs segment to generate different protein isoforms. Human carotid atherosclerotic plaques with a more stable phenotype are enriched with EDA containing fibronectin (FN-EDA). The aim of this study was to investigate the role of EDA containing fibronectin during atherogenesis. Mice constitutively expressing or lacking the EDA domain of fibronectin (EDA+/+ or EDA-/-)were crossed with ApoE-/- or LDL-R-/- mice and fed with a western type diet for 12 weeks. Lack of FN-EDA resulted in reduced atherosclerosis and in a plaque phenotype characterised by decreased calponin positive VSMC's (-15 %) and increased macrophages (+20 %). This was paralleled by increased MMP2, MMP9, and reduced TIMP2, collagen 1A1, 1A2 and 3A1 gene expression compared to that of wild-type and EDA+/+ mice. In vitro, VSMCs and macrophages isolated from EDA-/- miceshowed increased MMPs expression and activity compared to wild-type or EDA+/+ mice. Albumin-Cre recombinase/EDA+/+/ApoE-/- mice, which produceEDA containing FN only in peripheral tissues, presented an extension, a composition and a gene expression pattern in the atherosclerotic lesions similar to that of controls. The inclusion of EDA in FN results in larger atherosclerotic plaques compared to mice lacking EDA but with a more favourable phenotype in two animals models of atherosclerosis. This effect depends on the EDA-containing fibronectin produced by cells in the vasculature but not in the liver. These observations set the stage for investigating the properties of circulating EDA containing FN in improving plaque stability.

If It's Not One Thing, It's Another: An Inverse Relationship of Malignancy and Atherosclerotic Disease

Atherosclerosis and malignancy are pervasive pathological conditions that account for the bulk of morbidity and mortality in developed countries. Our current understanding of the patholobiology of these fundamental disorders suggests that inflammatory processes may differentially affect them; thus, atherosclerosis can be largely driven by inflammation, where as cancer often flourishes as inflammatory responses are modulated. A corollary of this hypothesis is that cancer (or its treatment may significantly attenuate atherosclerotic disease by diminishing host inflammatory response, suggesting potential therapeutic approaches. To evaluate the relationship between cancer and cardiovascular atherosclerotic disease, we assessed 1,024 autopsy reports from Brigham and Women's Hospital and performed correlative analyses on atherosclerotic severity and cancer prevalence. In gender- and age-matched populations, there is a statistically significant inverse correlation between history of malignancy and autopsy-proven atherosclerotic disease. In a second analysis, we evaluated 147,779 patients through analysis of the Harvard Catalyst SHRINE database and demonstrated a reduced non-coronary atherosclerotic disease rate: control (27.40%), leukemia/lymphoma (12.57%), lung (17.63%), colorectal (18.17%), breast (9.79%), uterus/cervix (11.47%), and prostate (18.40%). We herein report that, based on two separate medical records analysis, an inverse correlation between cancer and atherosclerosis. Furthermore, this correlation is not uniformly associated with anti-neoplastic treatment, suggesting that the inverse relationship may be in part attributable to an individual's intrinsic inflammatory propensity, and/or to inflammation-modulatory properties of neoplasms.

IDOL N342S Variant, Atherosclerosis Progression and Cardiovascular Disorders in the Italian General Population

Inducible degrader of the low density lipoprotein receptor (IDOL), is an E3 ubiquitin ligase that negatively modulates low density lipoprotein receptor (LDL-R) expression. Genome-wide association studies (GWAS) indicated that genetic variants in IDOL gene contributes to variation in LDL-C plasma levels and the detailed analysis of a specific locus resulted in the identification of the functional common single nucleotide polymorphism (SNP) rs9370867 (c.G1025A, p.N342S) associates with increased LDL-R degradation and increased LDL-C levels. These findings, however, were not confirmed in two other independent cohorts and no data about the impact of this variant on atherosclerosis progression and cardiovascular risk are available. Aim of this study was to investigate the association between a functional variant in IDOL and atherosclerosis progression in an Italian general population. 1384 subjects enrolled in the PLIC study (Progression of Lesions in the Intima of Carotid) were genotyped by Q-PCR allelic discrimination and the association with anthropometric parameters, plasma lipids and the carotid intima media thickness (cIMT) and the impact on cardiovascular disease (CVD) incidence were investigated. The N342S variant was not associated with changes of the plasma lipid profile among GG, AG or AA carriers, including total cholesterol (249±21, 249±19 and 248±21 mg/dl respectively), LDL-C (158±25, 161±22 and 160±23 mg/dL), cIMT (0.74±0.14, 0.75±0.17 and 0.77±0.15 mm) and CVD incidence. In agreement, the expression of LDLR and the uptake of LDL was similar in macrophages derived from GG and AA carriers. Taken together our findings indicate that the N342S variant does not impact plasma lipid profile and is not associated with atherosclerosis progression and CVD in the general population, suggesting that other variants in the IDOL gene might be functionally linked with cholesterol metabolism.

Markers of inflammation associated with plaque progression and instability in patients with carotid atherosclerosis

Atherosclerosis is the focal expression of a systemic disease affecting medium- and large-sized arteries, in which traditional cardiovascular risk factor and immune factors play a key role. It is well accepted that circulating biomarkers, including C-reactive protein and interleukin-6, reliably predict major cardiovascular events, including myocardial infarction or death. However, the relevance of biomarkers of systemic inflammation to atherosclerosis progression in the carotid artery is less established. The large majority of clinical studies focused on the association between biomarkers and subclinical atherosclerosis, that is, carotid intima-media thickening (cIMT), which represents an earlier stage of the disease. The aim of this work is to review inflammatory biomarkers that were associated with a higher atherosclerotic burden, a faster disease progression, and features of plaque instability, such as inflammation or neovascularization, in patients with carotid atherosclerotic plaque, which represents an advanced stage of disease compared with cIMT. The association of biomarkers with the occurrence of cerebrovascular events, secondary to carotid plaque rupture, will also be presented. Currently, the degree of carotid artery stenosis is used to predict the risk of future cerebrovascular events in patients affected by carotid atherosclerosis. However, this strategy appears suboptimal. The identification of suitable biomarkers could provide a useful adjunctive criterion to ensure better risk stratification and optimize management.

The role of T and B cells in human atherosclerosis and atherothrombosis

Far from being merely a passive cholesterol accumulation within the arterial wall, the development of atherosclerosis is currently known to imply both inflammation and immune effector mechanisms. Adaptive immunity has been implicated in the process of disease initiation and progression interwined with traditional cardiovascular risk factors. Although the body of knowledge regarding the correlation between atherosclerosis and immunity in humans is growing rapidly, a relevant proportion of it derives from studies carried out in animal models of cardiovascular disease (CVD). However, while the mouse is a well-suited model, the results obtained therein are not fully transferrable to the human setting due to intrinsic genomic and environmental differences. In the present review, we will discuss mainly human findings, obtained either by examination of post-mortem and surgical atherosclerotic material or through the analysis of the immunological profile of peripheral blood cells. In particular, we will discuss the findings supporting a pro-atherogenic role of T cell subsets, such as effector memory T cells or the potential protective function of regulatory T cells. Recent studies suggest that traditional T cell-driven B2 cell responses appear to be atherogenic, while innate B1 cells appear to exert a protective action through the secretion of naturally occurring antibodies. The insights into the immune pathogenesis of atherosclerosis can provide new targets in the quest for novel therapeutic targets to abate CVD morbidity and mortality.

Cardiovascular disease risk in an aging HIV population: not just a question of biology

PURPOSE OF REVIEW

The objective of this review is to appraise recently published literature that describes the relationship between HIV, biologic and environmental risk factors, and cardiovascular disease (CVD) risk with particular emphasis on the aging HIV population and to demonstrate that these biologic and environmental factors may interact to increase the risk of CVD in the HIV population.

RECENT FINDINGS

The mechanisms linking HIV and CVD are multifactorial and encompass biological and 'environmental' modalities including multimorbid conditions that co-occur with HIV, immunologic alterations associated with HIV, polypharmacy (which affects adherence and increases likelihood of adverse drug-drug interactions) and healthcare disparities in CVD risk reduction by HIV status.

SUMMARY

Data regarding optimal treatment strategies that balance immunological restoration and CVD risk reduction are needed.

Association of chronic hepatitis C infection with T-cell phenotypes in HIV-negative and HIV-positive women

BACKGROUND

Hepatitis C virus (HCV) viremia is thought to have broad systemic effects on the cellular immune system that go beyond its impact on just those T cells that are HCV specific. However, previous studies of chronic HCV and circulating T-cell subsets (activation and differentiation phenotypes) in HIV negatives used general population controls, rather than a risk-appropriate comparison group. Studies in HIV positives did not address overall immune status (total CD4⁺ count).

METHODS

We used fresh blood from HIV-positive and at-risk HIV-negative women, with and without chronic HCV, to measure percentages of activated CD4⁺ and CD8⁺ T cells, Tregs, and T-cell differentiation phenotypes (naive, central memory, effector memory (EM), and terminally differentiated effector). This included 158 HIV negatives and 464 HIV positives, of whom 18 and 63, respectively, were HCV viremic.

RESULTS

In multivariate models of HIV negatives, HCV viremia was associated with 25% fewer naive CD4⁺ (P = 0.03), 33% more EM CD4⁺ (P = 0.0002), and 37% fewer central memory CD8⁺ (P = 0.02) T cells. Among HIV positives, we observed only 1 of these 3 relationships: higher percentage of EM CD4⁺ among HCV viremic women. Furthermore, the association with EM CD4⁺ among HIV positives was limited to individuals with diminished immune status (total CD4⁺ count ≤500 cells/μL), as were associations of HCV viremia with higher percentages of activated CD4⁺ and Tregs. Among HIV positives with high CD4⁺ count, no significant associations were observed.

CONCLUSIONS

These data suggest that HCV viremia in HIV negatives is associated with accelerated T-cell differentiation, but among HIV positives, the impact of HCV viremia is less straightforward and varies by total CD4v count.

Circulating naive and memory CD4+ T cells and metabolic syndrome in patients with systemic lupus erythematosus: data from a primarily Mestizo population

OBJECTIVE

The aim of this study was to determine whether the proportions of naive and memory CD4(+) T cell are independently associated with the metabolic syndrome (MetS) in patients with SLE.

METHODS

This cross-sectional study was conducted in SLE patients seen at our rheumatology department between September 2013 and April 2014. CD4(+) T cell subpopulations were examined by flow cytometry. The association of MetS and CD4(+) T cell subpopulations was examined by Mann-Whitney U-test and by multivariable analysis, adjusting for all possible confounding variables.

RESULTS

One hundred and seventeen patients were evaluated. Their mean age was 44.6 years (S.D. 12.6), 109 (93.2%) were female and all patients were Mestizo (mixed Caucasian and Amerindian ancestry). Fifty-two patients (44.4%) presented with MetS. Disease duration was 7.6 years (S.D. 6.8). The percentage of naive CD4(+) T cells was 25.0 (S.D. 12.7) and memory CD4(+) T cells was 66.7 (S.D. 13.2) and the memory:naive CD4(+) T cell ratio was 4.3 (S.D. 5.6). In multivariable analysis, the percentage of naive CD4(+) T cells was negatively associated with the presence of MetS [odds ratio (OR) 0.959 (95% CI 0.923, 0.997), P = 0.033], whereas the percentage of memory CD4(+)T cells and the memory:naive CD4(+) T cell ratio were positively associated with its presence [OR 1.040 (95% CI 1.003, 1.078), P = 0.031 and OR 1.238 (95% CI 1.041, 1.472), P = 0.016, respectively].

CONCLUSION

In the SLE patients studied, a lower percentage of naive CD4(+) T cells, a higher percentage of memory CD4(+) T cells and the memory:naive CD4(+) T cell ratio were independently associated with the presence of MetS. This association could reflect the impact of immunosenescence among SLE patients with cardiovascular morbidity.

T cells in vascular inflammatory diseases

Inflammation of the human vasculature is a manifestation of many different diseases ranging from systemic autoimmune diseases to chronic inflammatory diseases, in which multiple types of immune cells are involved. For both autoimmune diseases and chronic inflammatory diseases several observations support a key role for T lymphocytes in these disease pathologies, but the underlying mechanisms are poorly understood. Previous studies in several autoimmune diseases have demonstrated a significant role for a specific subset of CD4⁺ T cells termed effector memory T (T_EM) cells. This expanded population of T_EM cells may contribute to tissue injury and disease progression. These cells exert multiple pro-inflammatory functions through the release of effector cytokines. Many of these cytokines have been detected in the inflammatory lesions and participate in the vasculitic reaction, contributing to recruitment of macrophages, neutrophils, dendritic cells, natural killer cells, B cells, and T cells. In addition, functional impairment of regulatory T cells paralyzes anti-inflammatory effects in vasculitic disorders. Interestingly, activation of T_EM cells is uniquely dependent on the voltage-gated potassium Kv1.3 channel providing an anchor for specific drug targeting. In this review, we focus on the CD4⁺ T cells in the context of vascular inflammation and describe the evidence supporting the role of different T cell subsets in vascular inflammation. Selective targeting of pathogenic T_EM cells might enable a more tailored therapeutic approach that avoids unwanted adverse side effects of generalized immunosuppression by modulating the effector functions of T cell responses to inhibit the development of vascular inflammation.

Cardiometabolic and immune factors associated with increased common carotid artery intima-media thickness and cardiovascular disease in patients with systemic lupus erythematosus

BACKGROUND AND AIM

Patients with systemic lupus erythematosus (SLE) have a higher prevalence of subclinical atherosclerosis and higher risk of cardiovascular (CV) events compared to the general population. The relative contribution of CV-, immune- and disease-related risk factors to accelerated atherogenesis in SLE is unclear.

METHODS AND RESULTS

Fifty SLE patients with long-lasting disease (mean age 44 ± 10 years, 86% female) and 50 sex- and age-matched control subjects were studied. Common carotid artery intima-media thickness (CCA-IMT) was used as a surrogate marker of atherosclerosis. We evaluated traditional and immune- and disease-related factors, assessed multiple T-cell subsets by 10-parameter-eight-colour polychromatic flow cytometry and addressed the effect of pharmacological therapies on CCA-IMT. In SLE patients, among several cardiometabolic risk factors, only high-density lipoprotein levels (HDL) and their adenosine triphosphate-binding cassette transporter 1 (ABCA-1)-dependent cholesterol efflux capacity were markedly reduced (p < 0.01), whereas the CCA-IMT was significantly increased (p = 0.03) compared to controls. CCA-IMT correlated with systolic blood pressure, low-density lipoprotein (LDL) cholesterol and body mass index (BMI), but not with disease activity and duration. The activated CD4(+)HLA-DR(+) and CCR5(+) T-cell subsets were expanded in SLE patients. Patients under hydroxychloroquine (HCQ) therapy showed lower CCA-IMT (0.62 ± 0.08 vs. 0.68 ± 0.10 mm; p = 0.03) and better risk-factor profile and presented reduced circulating pro-atherogenic effector memory T-cell subsets and a parallel increased percentage of naïve T-cell subsets.

CONCLUSION

HDL represents the main metabolic parameter altered in SLE patients. The increased CCA-IMT in SLE patients may represent the net result of a process in which 'classic' CV risk factors give a continuous contribution, together with immunological factors (CD4(+)HLA-DR(+) T cells) which, on the contrary, could contribute through flares of activity of various degrees over time. Patients under HCQ therapy present a modified metabolic profile, a reduced T-cell activation associated with decreased subclinical atherosclerosis.

HDL in innate and adaptive immunity

During infections or acute conditions high-density lipoproteins cholesterol (HDL-C) levels decrease very rapidly and HDL particles undergo profound changes in their composition and function. These changes are associated with poor prognosis following endotoxemia or sepsis and data from genetically modified animal models support a protective role for HDL. The same is true for some parasitic infections, where the key player appears to be a specific and minor component of HDL, namely apoL-1. The ability of HDL to influence cholesterol availability in lipid rafts in immune cells results in the modulation of toll-like receptors, MHC-II complex, as well as B- and T-cell receptors, while specific molecules shuttled by HDL such as sphingosine-1-phosphate (S1P) contribute to immune cells trafficking. Animal models with defects associated with HDL metabolism and/or influencing cell cholesterol efflux present features related to immune disorders. All these functions point to HDL as a platform integrating innate and adaptive immunity. The aim of this review is to provide an overview of the connection between HDL and immunity in atherosclerosis and beyond.

Dual opposing roles of adaptive immunity in hypertension

Hypertension involves remodelling and inflammation of the arterial wall. Interactions between vascular and inflammatory cells play a critical role in disease initiation and progression. T effector and regulatory lymphocytes, members of the adaptive immune system, play contrasting roles in hypertension. Signals from the central nervous system and the innate immune system antigen-presenting cells activate T effector lymphocytes and promote their differentiation towards pro-inflammatory T helper (Th) 1 and Th17 phenotypes. Th1 and Th17 effector cells, via production of pro-inflammatory mediators, participate in the low-grade inflammation that leads to blood pressure elevation and end-organ damage. T regulatory lymphocytes, on the other hand, counteract hypertensive effects by suppressing innate and adaptive immune responses. The present review summarizes and discusses the adaptive immune mechanisms that participate in the pathophysiology in hypertension.

Natural killer (NK) cell deficit in coronary artery disease: no aberrations in phenotype but sustained reduction of NK cells is associated with low-grade inflammation

Although reduced natural killer (NK) cell levels have been reported consistently in patients with coronary artery disease (CAD), the clinical significance and persistence of this immune perturbation is not clarified. In this study we characterized the NK cell deficit further by determining (i) differentiation surface markers and cytokine profile of NK cell subsets and (ii) ability to reconstitute NK cell levels over time. Flow cytometry was used to analyse NK cell subsets and the intracellular cytokine profile in 31 patients with non-ST elevation myocardial infarction (non-STEMI), 34 patients with stable angina (SA) and 37 healthy controls. In blood collected prior to coronary angiography, the proportions of NK cells were reduced significantly in non-STEMI and SA patients compared with controls, whereas NK cell subset analyses or cytokine profile measurements did not reveal any differences across groups. During a 12-month follow-up, the proportions of NK cells increased, although not in all patients. Failure to reconstitute NK cell levels was associated with several components of metabolic syndrome. Moreover, interleukin (IL)-6 levels remained high in patients with sustained NK cell deficit, whereas a decline in IL-6 (P < 0·001) was seen in patients with a pronounced increase in NK cells. In conclusion, we found no evidence that reduction of NK cells in CAD patients was associated with aberrations in NK cell phenotype at any clinical stage of the disease. Conversely, failure to reconstitute NK cell levels was associated with a persistent low-grade inflammation, suggesting a protective role of NK cells in CAD.

Bone marrow-specific knock-in of a non-activatable Ikkα kinase mutant influences haematopoiesis but not atherosclerosis in Apoe-deficient mice

Background

The Ikkα kinase, a subunit of the NF-κB-activating IKK complex, has emerged as an important regulator of inflammatory gene expression. However, the role of Ikkα-mediated phosphorylation in haematopoiesis and atherogenesis remains unexplored. In this study, we investigated the effect of a bone marrow (BM)-specific activation-resistant Ikkα mutant knock-in on haematopoiesis and atherosclerosis in mice.

Methods and Results

Apolipoprotein E (Apoe)-deficient mice were transplanted with BM carrying an activation-resistant Ikkα gene (Ikkα^AA/AAApoe^−/−) or with Ikkα^+/+Apoe^−/− BM as control and were fed a high-cholesterol diet for 8 or 13 weeks. Interestingly, haematopoietic profiling by flow cytometry revealed a significant decrease in B-cells, regulatory T-cells and effector memory T-cells in Ikkα^AA/AAApoe^−/− BM-chimeras, whereas the naive T-cell population was increased. Surprisingly, no differences were observed in the size, stage or cellular composition of atherosclerotic lesions in the aorta and aortic root of Ikkα^AA/AAApoe^−/− vs Ikkα^+/+Apoe^−/− BM-transplanted mice, as shown by histological and immunofluorescent stainings. Necrotic core sizes, apoptosis, and intracellular lipid deposits in aortic root lesions were unaltered. In vitro, BM-derived macrophages from Ikkα^AA/AAApoe^−/− vs Ikkα^+/+Apoe^−/− mice did not show significant differences in the uptake of oxidized low-density lipoproteins (oxLDL), and, with the exception of Il-12, the secretion of inflammatory proteins in conditions of Tnf-α or oxLDL stimulation was not significantly altered. Furthermore, serum levels of inflammatory proteins as measured with a cytokine bead array were comparable.

Conclusion

Our data reveal an important and previously unrecognized role of haematopoietic Ikkα kinase activation in the homeostasis of B-cells and regulatory T-cells. However, transplantation of Ikkα^AA mutant BM did not affect atherosclerosis in Apoe^−/− mice. This suggests that the diverse functions of Ikkα in haematopoietic cells may counterbalance each other or may not be strong enough to influence atherogenesis, and reveals that targeting haematopoietic Ikkα kinase activity alone does not represent a therapeutic approach.

Decreased naive and increased memory CD4(+) T cells are associated with subclinical atherosclerosis: the multi-ethnic study of atherosclerosis

Background

Adaptive immunity has been implicated in atherosclerosis in animal models and small clinical studies. Whether chronic immune activation is associated with atherosclerosis in otherwise healthy individuals remains underexplored. We hypothesized that activation of adaptive immune responses, as reflected by higher proportions of circulating CD4⁺ memory cells and lower proportions of naive cells, would be associated with subclinical atherosclerosis.

Methods and Findings

We examined cross-sectional relationships of circulating CD4⁺ naive and memory T cells with biomarkers of inflammation, serologies, and subclinical atherosclerosis in 912 participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Circulating CD4⁺ naive cells were higher in women than men and decreased with age (all p-values <0.0001). European-Americans had higher levels of naive cells and lower levels of memory cells compared with African-Americans and Hispanic-Americans (all p-values ≤0.0005). Lower naive/higher memory cells were associated with interleukin-6 levels. In multivariate models, cytomegalovirus (CMV) and H. Pylori titers were strongly associated with higher memory and lower naive cells (all p-values <0.05). Higher memory cells were associated with coronary artery calcification (CAC) level in the overall population [β-Coefficient (95% confidence interval (CI))  = 0.20 (0.03, 0.37)]. Memory and naive (inversely) cells were associated with common carotid artery intimal media thickness (CC IMT) in European-Americans [memory: β =  0.02 (0.006, 0.04); naive: β = −0.02 (−0.004, −0.03)].

Conclusions

These results demonstrate that the degree of chronic adaptive immune activation is associated with both CAC and CC IMT in otherwise healthy individuals, consistent with the known role of CD4⁺ T cells, and with innate immunity (inflammation), in atherosclerosis. These data are also consistent with the hypothesis that immunosenescence accelerates chronic diseases by putting a greater burden on the innate immune system, and suggest the importance of prospective studies and research into strategies to modulate adaptive immune activation in chronic disease states such as atherosclerosis.

The CD1d-natural killer T cell axis in atherosclerosis

A key role for 'lipid-sensing' CD1-restricted natural killer T (NKT) cells in the pathogenesis of atherosclerosis has been suggested. However, the biology of NKT cells remains poorly characterized, as in different experimental settings their activation was reported to both stimulate and suppress innate and adaptive immune responses. Most of the data from experimental models suggest that NKT cells are proatherogenic; however, it is debated whether the increase in atherosclerosis observed following NKT cell stimulation is a consequence of the inability to induce functional NKT cells rather than the proatherogenic nature of NKT cells. CD1d-expressing antigen-presenting cells and NKT cells were detected in mouse and human atherosclerotic lesions. Furthermore, several lysophospholipids and glycosphingolipids, known to accumulate in atherosclerotic plaques, are antigenic for human NKT cell clones. Lipid transfer proteins, such as apolipoprotein E and microsomal triglyceride transfer protein, are central to NKT cell responses. All these data suggest a profound relation between lipid metabolism, CD1d-NKT cell axis activation and atherosclerosis. In this review, we summarize the advances and gaps in our knowledge of NKT cell biology in the context of atherosclerosis as well as the possibility of influencing NKT cell polarization toward an atheroprotective phenotype.

Targeting oxidized LDL improves insulin sensitivity and immune cell function in obese Rhesus macaques

Oxidation of LDL (oxLDL) is a crucial step in the development of cardiovascular disease. Treatment with antibodies directed against oxLDL can reduce atherosclerosis in rodent models through unknown mechanisms. We demonstrate that through a novel mechanism of immune complex formation and Fc-γ receptor (FcγR) engagement, antibodies targeting oxLDL (MLDL1278a) are anti-inflammatory on innate immune cells via modulation of Syk, p38 MAPK phosphorylation and NFκB activity. Subsequent administration of MLDL1278a in diet-induced obese (DIO) nonhuman primates (NHP) resulted in a significant decrease in pro-inflammatory cytokines and improved overall immune cell function. Importantly, MLDL1278a treatment improved insulin sensitivity independent of body weight change. This study demonstrates a novel mechanism by which an anti-oxLDL antibody improves immune function and insulin sensitivity independent of internalization of oxLDL. This identifies MLDL1278a as a potential therapy for reducing vascular inflammation in diabetic conditions.

T-helper type 1 bias in healthy people is associated with cytomegalovirus serology and atherosclerosis: the Multi-Ethnic Study of Atherosclerosis

Background

Although T‐helper type 1 (Th1) cells are considered important in atherosclerosis, the relationships between Th1 and Th2 cells and atherosclerosis have not been examined in population‐based studies.

Methods and Results

We measured Th cells as a percentage of lymphocytes by flow cytometry using CD4 staining (%CD4) in 917 participants of the Multi‐Ethnic Study of Atherosclerosis. We also measured interferon gamma–positive and interleukin‐4‐positive CD4⁺ cells, representing Th1 and Th2 subpopulations (%Th1 and %Th2), respectively. We found that %CD4 was 1.5% lower per 10 years of age (P<0.0001). Whites had higher %CD4 and lower %Th1 and %Th2 values than other race/ethnic groups. Body mass index (BMI) and blood pressure were associated with %CD4, but no traditional cardiovascular disease (CVD) risk factors were associated with %Th1 or %Th2. In multivariable models, the major independent variable associated with %Th1 was cytomegalovirus (CMV) antibody titer, with minor contributions from age, sex, seasonality, and interleukin‐6. In models with coronary artery calcification level as the outcome, significant independent variables included age, sex, smoking status, and %Th1 (β=0.25; P≤0.01). Both %Th1 and %Th2 were associated with common carotid intimal media thickness (β=0.02 and −0.02, respectively; both P<0.05), as were age, sex, race/ethnicity, blood pressure, and BMI.

Conclusions

Th1 bias is associated with subclinical atherosclerosis in a multiethnic population. The main Th1 correlate was CMV infectious burden. These findings are consistent with a role of Th1 cells in atherosclerosis and suggest the importance of prospective studies of T‐helper cell biasing in CVD.

FOXP3 demethylation as a means of identifying quantitative defects in regulatory T cells in acute coronary syndrome

OBJECTIVE

The contribution of regulatory T cells (Tregs) to the pathogenesis of acute coronary syndrome (ACS) remains poorly understood. One core obstacle is the lack of Treg-specific markers. A highly conserved CpG enriched element in forkhead box P3 intron 1 (FOXP3 i l) is unmethylated only in Tregs, and measuring the unmethylation of FOXP3 i l can be used to identify the role of Tregs in clinical diseases. This study investigated whether analyzing the demethylation status of FOXP3 i 1 is a more reliable means than using Treg-specific surface markers in ACS.

METHODS AND RESULTS

We evaluated circulating Tregs percentages on different levels including cell frequencies (CD4(+)CD25(hi)FOXP3(+)Tregs and CD4(+)CD25(hi)CD45(+)naïve Tregs) or FOXP3 mRNA, FOXP3 i 1 demethylation status and related cytokine secretion in 89 patients with ACS and 35 controls. FOXP3 i 1 demethylation assay showed that the amount of Tregs in ACS patients was significantly reduced than that in controls (p = 0.0005). However, flow cytometry analysis did not identify any reduction of CD4(+)CD25(hi)FOXP3(+)Tregs in ACS patients. Notably, younger patients had higher percentage of CD4(+)CD25(hi)FOXP3(+)Tregs but decreased percentage of CD4(+)CD25(hi)CD45(+)naïve Tregs than either controls or older patients. Furthermore, a DNA hypomethylation agent increased the amount of CD4(+)CD25(hi)FOXP3(+)Tregs and Tregs related cytokine IL-10 and suppressed the production of pro-inflammatory cytokine interferon-γ by inducing FOXP3 i 1 demethylation in vitro.

CONCLUSIONS

A quantitative defect of Tregs, suggestive of decreased peripheral tolerance, could be a potential hallmark of ACS disease. Targeting FOXP3 i l demethylation might elevate the inhibitory activity of Tregs in ACS.

Redox regulation of T-cell function: from molecular mechanisms to significance in human health and disease

Reactive oxygen species (ROS) are thought to have effects on T-cell function and proliferation. Low concentrations of ROS in T cells are a prerequisite for cell survival, and increased ROS accumulation can lead to apoptosis/necrosis. The cellular redox state of a T cell can also affect T-cell receptor signaling, skewing the immune response. Various T-cell subsets have different redox statuses, and this differential ROS susceptibility could modulate the outcome of an immune response in various disease states. Recent advances in T-cell redox signaling reveal that ROS modulate signaling cascades such as the mitogen-activated protein kinase, phosphoinositide 3-kinase (PI3K)/AKT, and JAK/STAT pathways. Also, tumor microenvironments, chronic T-cell stimulation leading to replicative senescence, gender, and age affect T-cell susceptibility to ROS, thereby contributing to diverse immune outcomes. Antioxidants such as glutathione, thioredoxin, superoxide dismutase, and catalase balance cellular oxidative stress. T-cell redox states are also regulated by expression of various vitamins and dietary compounds. Changes in T-cell redox regulation may affect the pathogenesis of various human diseases. Many strategies to control oxidative stress have been employed for various diseases, including the use of active antioxidants from dietary products and pharmacologic or genetic engineering of antioxidant genes in T cells. Here, we discuss the existence of a complex web of molecules/factors that exogenously or endogenously affect oxidants, and we relate these molecules to potential therapeutics.

Long pentraxin 3: experimental and clinical relevance in cardiovascular diseases

Pentraxin 3 (PTX3) is an essential component of the humoral arm of innate immunity and belongs, together with the C-reactive protein (CRP) and other acute phase proteins, to the pentraxins' superfamily: soluble, multifunctional, pattern recognition proteins. Pentraxins share a common C-terminal pentraxin domain, which in the case of PTX3 is coupled to an unrelated long N-terminal domain. PTX3 in humans, like CRP, correlates with surrogate markers of atherosclerosis and is independently associated with the risk of developing vascular events. Studies addressing the potential physiopathological role of CRP in the cardiovascular system were so far inconclusive and have been limited by the fact that the sequence and regulation have not been conserved during evolution between mouse and man. On the contrary, the conservation of sequence, gene organization, and regulation of PTX3 supports the translation of animal model findings in humans. While PTX3 deficiency is associated with increased inflammation, cardiac damage, and atherosclerosis, the overexpression limits carotid restenosis after angioplasty. These observations point to a cardiovascular protective effect of PTX3 potentially associated with the ability of tuning inflammation and favor the hypothesis that the increased levels of PTX3 in subjects with cardiovascular diseases may reflect a protective physiological mechanism, which correlates with the immunoinflammatory response observed in several cardiovascular disorders.

-374 T/A RAGE polymorphism is associated with chronic kidney disease progression in subjects affected by nephrocardiovascular disease

BACKGROUND

Chronic kidney disease (CKD) patients present elevated advanced glycation end products (AGEs) blood levels. AGEs promote inflammation through binding to their receptor (RAGE), located on the membrane of mesangial cells, endothelial cells and macrophages. Several genetic polymorphisms influence RAGE transcription, expression and activity, including the substitution of a thymine with an adenine (T/A) in the position -374 of the gene promoter of RAGE. Our study investigates the role of -374 T/A RAGE polymorphism in CKD progression in subjects affected by nephrocardiovascular disease.

METHODS

174 patients (119 males (68.4%) mean age 67.2±0.88 years; 55 females (31.6%): mean age 65.4±1.50 years) affected by mild to moderate nephrocardiovascular CKD were studied. Each subject was prospectively followed for 84 months, every 6-9 months. The primary endpoint of the study was a rise of serum creatinine concentrations above 50% of basal values or end stage renal disease.

RESULTS

Carriers of the A/A and T/A genotype presented higher plasma levels of interleukin 6 (A/A 29.5±15.83; T/A 30.0±7.89, vs T/T 12.3±5.04 p = 0.01 for both) and Macrophages chemoattractant protein 1 (A/A 347.1±39.87; T/A 411.8±48.41, vs T/T 293.5±36.20, p = 0.04 for both) than T/T subjects. Carriers of the A allele presented a faster CKD progression than wild type patients (Log-Rank test: Chi square = 6.84, p = 0,03). Cox regression showed that -374 T/A RAGE polymorphism (p = 0.037), albuminuria (p = 0.01) and LDL cholesterol (p = 0.038) were directly associated with CKD progression. HDL cholesterol (p = 0.022) and BMI (p = 0.04) were inversely related to it. No relationship was found between circulating RAGE and renal function decline.

CONCLUSIONS

-374 T/A RAGE polymorphism could be associated with CKD progression and inflammation. Further studies should confirm this finding and address whether inhibiting RAGE downstream signalling would be beneficial for CKD progression.

T-helper 2 immunity is associated with reduced risk of myocardial infarction and stroke

OBJECTIVE

Experimental studies in mice have attributed T-helper (Th) 1 and Th2 cells important roles in atherosclerosis, but the clinical importance of these cells in cardiovascular disease (CVD) remains to be clarified. Here, we investigated associations between Th1 and Th2 cells, carotid intima-media thickness, and cardiovascular risk.

METHODS AND RESULTS

Blood drawn at baseline and incident cardiovascular events during 15-year follow-up were assessed in 700 participants. Baseline Th1 (CD3(+)CD4(+)interferon-γ(+)) and Th2 (CD3(+)CD4(+)interleukin-4(+)) cells were analyzed by flow cytometry, and cytokine-release from activated mononuclear leukocytes was measured by multiplex technology. High numbers of Th2 cells were independently associated with decreased mean common carotid intima-media thickness. High numbers of Th2 cells were also independently associated with a reduced risk of acute myocardial infarction in women (hazard ratio, 0.19; 95% confidence interval, 0.06-0.56; P=0.002 for the highest versus the lowest tertile of Th2 cells). Moreover, release of the Th2 cytokine interleukin-4 from activated mononuclear leukocytes was independently associated with a reduced risk of CVD. No independent associations between Th1 cells and carotid intima-media thickness or CVD risk were found.

CONCLUSIONS

Our observations provide the first clinical evidence for a protective role of Th2 immunity in CVD. They also suggest this protection is more prominent in women than in men. In spite of convincing evidence from experimental studies, we found no support for a role of Th1 immunity in CVD.