Mechanisms of disease: the evolving role of regulatory T cells in atherosclerosis. ACTA ACUST UNITED AC. 2008;5:531-540. [PMID: 18607396 DOI: 10.1038/ncpcardio1279]

The Impact of Exercise on Immunity, Metabolism, and Atherosclerosis

Physical exercise represents an effective preventive and therapeutic strategy beneficially modifying the course of multiple diseases. The protective mechanisms of exercise are manifold; primarily, they are elicited by alterations in metabolic and inflammatory pathways. Exercise intensity and duration strongly influence the provoked response. This narrative review aims to provide comprehensive up-to-date insights into the beneficial effects of physical exercise by illustrating the impact of moderate and vigorous exercise on innate and adaptive immunity. Specifically, we describe qualitative and quantitative changes in different leukocyte subsets while distinguishing between acute and chronic exercise effects. Further, we elaborate on how exercise modifies the progression of atherosclerosis, the leading cause of death worldwide, representing a prime example of a disease triggered by metabolic and inflammatory pathways. Here, we describe how exercise counteracts causal contributors and thereby improves outcomes. In addition, we identify gaps that still need to be addressed in the future.

Circulating Regulatory B-Lymphocytes in Patients with Acute Myocardial Infarction: A Pilot Study

Background: Inflammation plays on important role in plaque instability and acute coronary syndromes. The anti-inflammatory effects of B-regulatory lymphocytes (B-regs) in atherosclerosis was tested mainly in animal models with inconclusive results. Herein, we studied for the first time, levels of circulating B-regs in patients with acute myocardial infarction (MI). Methods: We examined circulating levels of B-regs by flow cytometry in 29 patients with recent ST-segment elevation MI and 18 patients with stable angina pectoris (SAP) and coronary artery disease. We re-assessed B-reg levels on average 4 months later. Results: The mean level of CD20+ cells was similar in patients with MI and patients with SAP (p = 0.60). The levels of CD24hiCD38hi cells among CD20+ cells were 5.7 ± 4% and 11.6 ± 6% in patients with MI and SAP, respectively, (p < 0.001). The level of CD24hiCD38hi B-regs remained related to acute MI after correcting for age, gender, and risk factors. Circulating levels of CD24hiCD38hi B-regs in patients with MI did not change significantly at follow-up in a small patient groups (p = 0.408). Conclusions: Circulating B-regs are reduced in patients with MI compared to patients with SAP. This finding may shed further light on the inflammatory pathophysiologic factors related to plaque rupture.

DNA methylation changes and inflammaging in aging-associated diseases

Aging as an inevitable phenomenon is associated with pervasive changes in physiological functions. There is a relationship between aging and the increase of several chronic diseases. Most age-related disorders are accompanied by an underlying chronic inflammatory state, as demonstrated by local infiltration of inflammatory cells and greater levels of proinflammatory cytokines in the bloodstream. Within inflammaging, many epigenetic events, especially DNA methylation, change. During the aging process, due to aberrations of DNA methylation, biological processes are disrupted, leading to the emergence or progression of a variety of human diseases, including cancer, neurodegenerative disorders, cardiovascular disease and diabetes. The focus of this review is on DNA methylation, which is involved in inflammaging-related activities, and how its dysregulation leads to human disorders.

The potential targets in immunotherapy of atherosclerosis

Cardiovascular disease is the most common cause of death, which has the highest mortality rate worldwide. Although a diverse range of inflammatory diseases can affect the cardiovascular system, however, heart failure and stroke occur due to atherosclerosis. Atherosclerosis is a chronic autoinflammatory disease of small to large vessels in which different immune mediators are involved in lipid plaque formation and inflammatory vascular remodeling process. A better understanding of the pathophysiology of atherosclerosis may lead to uncovering immunomodulatory therapies. Despite present diagnostic and therapeutic methods, the lack of immunotherapy in the prevention and treatment of atherosclerosis is perceptible. In this review, we will discuss the promising immunological-based therapeutics and novel preventive approaches for atherosclerosis. This study could provide new insights into a better perception of targeted therapeutic pathways and biological therapies.

Adaptive immune disorders in hypertension and heart failure: focusing on T-cell subset activation and clinical implications

: Hypertension is a growing health concern worldwide. Established hypertension is a causative factor of heart failure, which is characterized by increased vascular resistance and intractable uncontrolled blood pressure. Hypertension and heart failure have multiple causes and complex pathophysiology but cellular immunity is thought to contribute to the development of both. Recent studies showed that T cells play critical roles in hypertension and heart failure in humans and animals, with various stimuli leading to the formation of effector T cells that infiltrate the cardiovascular wall. Monocytes/macrophages also accumulate in the cardiovascular wall. Various cytokines (e.g. interleukin-6, interleukin-17, interleukin-10, tumor necrosis factor-α, and interferon-γ) released from immune cells of various subtypes promote vascular senescence and elastic laminal degradation as well as cardiac fibrosis and/or hypertrophy, leading to cardiovascular structural alterations and dysfunction. Recent laboratory evidence has defined a link between inflammation and the immune system in initiation and progression of hypertension and heart failure. Moreover, cross-talk among natural killer cells, adaptive immune cells (T cells and B cells), and innate immune cells (i.e. monocytes, macrophages, neutrophils, and dendritic cells) contributes to end-cardiovasculature damage and dysfunction in hypertension and heart failure. Clinical and experimental studies on the diagnostic potential of T-cell subsets revealed that blood regulatory T cells, CD4 cells, CD8 T cells, and the ratio of CD4 to CD8 T cells show promise as biomarkers of hypertension and heart failure. Therapeutic interventions to suppress activation of these cells may prove beneficial in reducing end-organ damage and preventing consequences of cardiovascular failure, including hypertension of heart failure.

Immune Disorder in Atherosclerotic Cardiovascular Disease - Clinical Implications of Using Circulating T-Cell Subsets as Biomarkers

Atherosclerotic cardiovascular disease (ACVD) is an inflammatory phenomenon that leads to structural abnormality in the vascular lumen due to the formation of atheroma by the deposition of lipid particles and inflammatory cytokines. There is a close interaction between innate immune cells (neutrophils, monocyte, macrophages, dendritic cells) and adaptive immune cells (T and B lymphocytes) in the initiation and progression of atherosclerosis. According to novel insights into the role of adaptive immunity in atherosclerosis, the activation of CD4⁺T cells in response to oxidized low-density lipoprotein-antigen initiates the formation and facilitates the propagation of atheroma, whereas CD8⁺T cells cause the rupture of a developed atheroma by their cytotoxic nature. Peripheral CD4⁺and CD8⁺T-cell counts were altered in patients with other cardiovascular risk factors. Furthermore, on evaluation of the feasibility of immune cells as a diagnostic tool, the blood CD4⁺(helper), CD8⁺(cytotoxic), and CD4⁺CD25⁺Foxp3⁺(regulatory) T cells and the ratio of CD4 to CD8 cells hold promise as biomarkers of coronary artery disease and their subtypes. T cells also could be a therapeutic target for cardiovascular diseases. The goal of this review was therefore to summarize the available information regarding immune disorders in ACVD with a special focus on the clinical implications of circulating T-cell subsets as biomarkers.

Healthy Adult LDL-C Bears Reverse Association with Serum IL-17A Levels

Background:

Hypercholesterolemia is a modifiable risk factor in atherosclerosis with a complex association with inflammation.

Objective:

In the present study, the association between low-density lipoprotein cholesterol (LDL-C) and interleukin 17A (IL-17A), as an inflammatory cytokine, was investigated. In addition to IL-17A, serum levels of interleukin 23 (IL-23) and transforming growth factor β (TGF-β), as effective cytokines in T helper 17 cell (Th17) development, were also determined.

Method:

Cytokine levels were measured using enzyme-linked immunosorbent assay (ELISA) in healthy subjects with LDL-C<130 versus LDL-C=>130 mg/dL.

Results:

Although IL-17A is an inflammatory cytokine and a positive association between its levels and LDL-C is expected, the data obtained in this study provide support for a reverse association (p<0.05).

Conclusion:

Inflammation plays a major role in atherosclerosis development; however, various inflammatory components involved in atherosclerosis assert their own unique association with hypercholesterolemia.

Decreased Helios Expression in Regulatory T Cells in Acute Coronary Syndrome

Regulatory T cells (Tregs) play an essential role in acute coronary syndrome (ACS). However, there is debate about which Treg subsets are truly critical to ACS. Helios, a transcription factor, was recently reported to be a bona fide marker for natural Tregs or activated Tregs with a suppression function, but little is known about its role in ACS. We therefore examined Helios+ Tregs in patients with ACS, patients with stable angina, and control subjects. 73 patients with ACS, 30 patients with stable angina, and 48 control subjects were enrolled. The frequencies and estimated absolute numbers of different Treg subsets in peripheral blood were measured by flow cytometry. Plasma cytokine level was measured by ELISA. The mRNA expression of Foxp3 and Helios in purified CD4+ T cells was determined by RT-PCR. Helios+ Tregs was decreased significantly in patients with ACS. The frequency and estimated absolute numbers of CD4+Foxp3+Helios+ Tregs were negatively correlated with IL-6 and positively correlated with circulating level of TGF-beta1 and HDL-C. The mRNA expression of Foxp3 and Helios was decreased in CD4+ T cells from patients with ACS. In summary, Helios+ Tregs was downregulated in patients with ACS and may play a role in ACS.

Crosstalk Between Enzyme Matrix Metalloproteinases 2 and 9 and Regulatory T Cell Immunity in the Global Burden of Atherosclerosis

Changes in immune and inflammatory responses may play a crucial role in the development and progression of atherosclerosis, as an autoimmune, chronic and progressive inflammatory disease. Immunological activity and vascular inflammation during atherosclerosis can be modulated by autoimmune responses against self-antigens, according to changeable risk factors (cholesterol, oxidized low-density lipoprotein (ox-LDL) in the vascular wall, fatty acids, etc.), and accompanied by accumulation of leucocytes and proinflammatory cytokines, which stimulate the transcription of matrix metalloproteinases (MMPs), whose concentration are increased in foam cell-rich regions. Regulatory T cells (Tregs) represent a unique subpopulation of T cells specialized in the regulation of immune response and in the suppression of proatherogenic T cells. The aim of our study was to examine the interactions between the concentration of enzyme matrix metalloproteinases 2 and 9 (MMP-2 and 9) in urine and the percentage of Tregs in peripheral blood of two groups of patients: with carotid artery stenosis (CAS), undergoing surgery and with mild atherosclerosis (A) from general practice. The method of enzyme immunoassay (ELISA) was used to determine enzyme MMP expression, and Tregs was examined by flow cytometric analysis. Our data have showed a large increase in the enzyme MMP-2 and 9 in the urine of CAS and A patients in comparison with healthy controls and indicated this method as an easy marker for the monitoring of the development of atherosclerosis. Simultaneously, the diminished number of Tregs in the same patients pointed the importance of these regulatory mechanisms in the etiopathogenesis of atherosclerosis and possible Tregs-mediated therapy.

Stabilization of high-risk plaques

The prevalence of atherosclerotic cardiovascular diseases (ASCVDs) is increasing globally and they have become the leading cause of death in most countries. Numerous experimental and clinical studies have been conducted to identify major risk factors and effective control strategies for ASCVDs. The development of imaging modalities with the ability to determine the plaque composition enables us to further identify high-risk plaque and evaluate the effectiveness of different treatment strategies. While intensive lipid-lowering by statins can stabilize or even regress plaque by various mechanisms, such as the reduction of lipid accumulation in a necrotic lipid core, the reduction of inflammation, and improvement of endothelial function, there are still considerable residual risks that need to be understood. We reviewed important findings regarding plaque vulnerability and some encouraging emerging approaches for plaque stabilization.

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.

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.

Inflammatory environment and oxidized LDL convert circulating human proangiogenic cells into functional antigen-presenting cells

The function of human circulating PACs has been described extensively. However, little focus has been placed on understanding how these cells differ in their functions in the presence of microenvironments mimicking vascular inflammation. We hypothesized that exposure to proinflammatory cytokines or the oxLDL, an autoantigen abundant in advanced atherosclerotic plaques, converts PACs into immune-modulating/proinflammatory cells. Hence, we examined the effect of oxLDL and inflammatory stimuli on their phenotype by use of a functional genomics model based on secretome and whole genome transcriptome profiling. PACs obtained from culturing a PBMC fraction in angiogenic medium were primed with DC differentiation cytokines and then exposed to proinflammatory cytokines or oxLDL. Under these conditions, PACs converted into APCs, expressed maturation markers CD80 and CD83, and showed an increased up-regulation of CD86. APCcy and APCox induced a robust T cell BrdU incorporation. Despite a similar ability to induce lymphocyte proliferation, APCcy and APCox differed for the secretory pathway and mRNA expression. Analysis of the differentially expressed genes identified 4 gene "clusters," showing reciprocal modulation in APCcy vs. APCox, justifying, according to functional genomics analyses, a different putative function of the cells in antigen processing. Together, these data show that treatment with inflammatory cytokines or oxLDL converts human PAC phenotypes and functions into that of APCs with similar lymphocyte-activating ability but distinct maturation degree and paracrine functions.

Atherosclerosis and the role of immune cells

Atherosclerosis is a chronic inflammatory disease arising from lipids, specifically low-density lipoproteins, and leukocytes. Following the activation of endothelium with the expression of adhesion molecules and monocytes, inflammatory cytokines from macrophages, and plasmacytoid dendritic cells, high levels of interferon (IFN)-α and β are generated upon the activation of toll-like receptor-9, and T-cells, especially the ones with Th1 profile, produce pro-inflammatory mediators such as IFN-γ and upregulate macrophages to adhere to the endothelium and migrate into the intima. This review presents an exhaustive account for the role of immune cells in the atherosclerosis.

Decreased regulatory T cells in vulnerable atherosclerotic lesions: imbalance between pro- and anti-inflammatory cells in atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial wall in which presentation of autoantigens by dendritic cells (DCs) leads to the activation of T cells. Anti-inflammatory cells like Tregs counterbalance inflammation in atherogenesis. In our study, human carotid plaque specimens were classified as stable (14) and unstable (15) according to established morphological criteria. Vessel specimens (n = 12) without any signs of atherosclerosis were used as controls. Immunohistochemical staining was performed to detect different types of DCs (S100, fascin, CD83, CD209, CD304, and CD123), proinflammatory T cells (CD3, CD4, CD8, and CD161), and anti-inflammatory Tregs (FoxP3). The following results were observed: in unstable lesions, significantly higher numbers of proinflammatory cells like DCs, T helper cells, cytotoxic T cells, and natural killer cells were detected compared to stable plaques. Additionally, there was a significantly higher expression of HLA-DR and more T cell activation (CD25, CD69) in unstable lesions. On the contrary, unstable lesions contained significantly lower numbers of Tregs. Furthermore, a significant inverse correlation between myeloid DCs and Tregs was shown. These data suggest an increased inflammatory state in vulnerable plaques resulting from an imbalance of the frequency of local pro- and anti-inflammatory immune cells.

Effect of hyperlipidemia on Foxp3 expression in apolipoprotein E-knockout mice

BACKGROUND

The transcription factor forkhead box P3 (Foxp3) plays an essential role in the development and function of regulatory T cells.

AIMS

To examine the effect of hyperlipidemia on the expression of Foxp3 in mice.

METHODS

Twenty-four 8-week-old male apolipoprotein E (ApoE) mice on a C57BL/6 background were randomly divided into control group and high fat diet group, 12 mice per group. The blood-lipid levels, the number of Foxp3CD4 CD25 T cells, and the size of the atherosclerotic lesions in every group were measured. The expression levels of Foxp3 in different tissues were detected.

RESULTS

Compared with the control group, the level of plasma lipids was significantly higher in the high fat-fed group, but the number and function of Foxp3CD4 CD25 T cells, the levels of Foxp3 protein expression, and Foxp3 gene transcript in selected tissues were lower in the high fat-fed group.

CONCLUSION

Hyperlipidemia inhibits the expression and function of Foxp3 in various immune organs, which may be one of the mechanisms by which hyperlipidemia aggravates the formation of atherosclerosis.

Human sLZIP promotes atherosclerosis via MMP-9 transcription and vascular smooth muscle cell migration

Atherosclerosis is a chronic inflammatory response of the vascular wall, and immune responses are involved in every phase of atherosclerosis, from initiation, to progression, and finally to plaque rupture. Cytokines are the major atherogenic mediators that promote plaque formation and progression by activation of inflammatory cells. They induce expressions of matrix metalloproteinases (MMPs), leading to vascular smooth muscle cell (VSMC) migration in atherosclerotic lesions. Although chronic inflammatory mediators, including tumor necrosis factor α (TNF-α) and MMPs, exacerbate atherosclerosis, the molecular mechanism of atherogenesis remains unclear. In this study we investigated the role of a novel transcription factor the human small leucine zipper protein (sLZIP) in TNF-α-induced MMP expression, VSMC migration, and atherosclerosis progression. The proinflammatory cytokine TNF-α enhanced sLZIP expression by 3-fold via activation of NF-κB signaling. sLZIP induced MMP-9 transcription and the proteolytic activity of MMP-9 by 2.8- and 3.2-fold (P< 0.05), respectively, in macrophages, leading to enhancement of VSMC migration by 2.7-fold (P<0.005). sLZIP(OE/+) (sLZIP transgenic); LDLR(-/-) mice fed a high-cholesterol diet exhibited enhanced arterial plaque formation and increased VSMC migration from the media into the intima by 2.8- and 2.6-fold (P<0.01), respectively, compared with atherosclerosis-prone LDLR(-/-) mice. These results indicate that human sLZIP plays a critical role in development of atherosclerosis and can be used as a therapeutic target molecule for treatment of atherosclerosis.

Porphyromonas gingivalis infection enhances Th17 responses for development of atherosclerosis

OBJECTIVES

Porphyromonas gingivalis has been shown to associate with the development of atherosclerosis. Recent studies indicate that IL-17-producing T helper 17 (Th17) cells have been correlated with the emergence of atherosclerosis. Therefore, we investigated whether the Th17 cell response and expression of Th17-related molecules, in contrast with Th1- and Treg cells, are enhanced by P. gingivalis-challenge in Apolipoprotein E knockout (ApoE KO) mice.

DESIGN

Five mice were intravenously injected with P. gingivalis three times a week for 3 weeks and killed at 15 weeks of age. The proximal aorta lesion area, flow cytometry analysis and IL-17, IL-10, IFN-γ, and IL-1β levels in splenic cultures, and expression of Th17-related molecules in spleen and hearts were examined.

RESULTS

P. gingivalis-challenge showed notable accumulation of atherosclerotic plaques by Oil Red O-staining in ApoE KO mice. Intracellular cytokine staining revealed that significantly elevated CD4(+) interleukin (IL)-17A(+) T cells and slightly increased CD4(+) Foxp3(+) T cells was recognized in spleen cells of P. gingivalis-challenged mice compared with those from non-infected mice. P. gingivalis-challenge significantly increased IL-17 and IL-1β production and RORγt expression in splenic cells. Furthermore, the expression of Th17-related genes such as IL-6, TGF-β, RORγt and STAT3 were elevated in splenic cells as well as heart tissue of P. gingivalis-challenged mice.

CONCLUSION

These results suggest that P. gingivalis infection may enhance pro-inflammatory Th17 cell responses in lesion areas and spleen, thereby accelerating atherosclerosis.

Sublingual Vaccine with GroEL Attenuates Atherosclerosis

Autoimmune responses to heat-shock protein 60 (HSP60) contribute to the progression of atherosclerosis, whereas immunization with HSP60 may induce atheroprotective responses. We assessed the capacity of an atheroprotective vaccine that targeted a recombinant HSP60 from Porphyromonas gingivalis (rGroEL) to induce a protective mucosal immune response. Female apolipoprotein E-deficient spontaneously hyperlipidemic (Apoeshl) mice received sublingual delivery of rGroEL prior to P. gingivalis 381 injection. The animals were euthanized 16 weeks later. Sublingual immunization with rGroEL induced significant rGroEL-specific serum IgG responses. Antigen-specific cells isolated from spleen produced significantly high levels of IL-10 and IFN-γ after antigen re-stimulation in vitro. Flow cytometric analysis indicated that the frequencies of both IL-10+ and IFN-γ+ CD4+ Foxp3+ cells increased significantly in submandibular glands (SMG). Furthermore, sublingual immunization with rGroEL significantly reduced atherosclerosis lesion formation in the aortic sinus and decreased serum CRP, MCP-1, and ox-LDL levels. These findings suggest that sublingual immunization with rGroEL is associated with the increase of IFNγ+ or IL-10+ Foxp3+ cells in SMG and a systemic humoral response, which could be an effective strategy for the prevention of naturally occurring or P. gingivalis-accelerated atherosclerosis.

Psoriasis as a systemic disease

Psoriasis is an inflammatory immune-mediated disease that affects the skin and has pathogenic effects with systemic impact. The relationship between psoriasis and comorbidities remains controversial. The hypothesis of a causative role of psoriasis in its cardiovascular and metabolic comorbidities is based on pathophysiologic concepts establishing a link between chronic inflammation in psoriasis, endothelial dysfunction, formation of atherosclerotic plaques, and the different compounds of metabolic syndrome. Psoriasis management has to be multidisciplinary. It implicates identification and treatment of psychological disorders, addictions, and associated cardiovascular and metabolic diseases, together with improvement of quality of life of patients.

Molecular biology of atherosclerosis

At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.

Atherosclerosis in systemic lupus erythematosus

Accelerated atherosclerosis and its long-term sequelae are a major cause of late mortality among patients with systemic lupus erythematosus (SLE). Traditional Framingham risk factors such as hypertension, hypercholesterolemia, diabetes, and smoking do not account in entirety for this risk. SLE specific factors like disease activity and duration, use of corticosteroids, presence of antiphospholipid antibodies, and others are important risk factors. SLE is considered a coronary heart disease; equivalent and aggressive management of all traditional risk factors is recommended. Despite their role in primary and secondary prevention in the general population, statins seem to have no effect on cardiovascular outcomes in adult or pediatric SLE populations. The use of hydroxychloroquine has a cardioprotective effect, and mycophenolate mofetil may reduce cardiovascular events based on basic science data and data from the transplant population. The role of vitamin D supplementation and treatment of hyperhomocysteinemia remain controversial, but due to the safety of therapy and the potential benefit, they remain as optional therapies.

Methylation of FOXP3 in regulatory T cells is related to the severity of coronary artery disease

OBJECTIVES

Regulatory T (Treg) cells have been shown to play a protective role in experimental atherosclerosis. However, it is unclear whether Tregs can protect from rupture of vulnerable plaque in patients with atherosclerosis. Demethylation of the DNA encoding the transcription factor forkhead box P3 (FOXP3) was found to be essential for the stable maintenance of the suppressive properties of Tregs. We aimed to evaluate Treg levels in patients with acute coronary syndrome (ACS) using a method based on Treg-specific DNA demethylation within the FOXP3 gene.

METHODS AND RESULTS

Peripheral blood was collected to determine Treg levels by PCR-based DNA methylation analysis. We found that Treg levels were decreased in patients with ACS compared with normal coronary controls. The decrease in Tregs was associated with the severity of the ACS. Furthermore, up-regulation of DNA-methyltransferases was detected in CD4(+)CD25(+) Tregs obtained from ACS patients as compared to those from normal coronary controls. A dose-dependent increase in the methylation of the Treg-specific demethylated region in FOXP3 was observed in cultures of PBMCs with ox-LDL. Moreover, the ox-LDL-induced Treg effects could be restored by loading (-)-epigallocatechin-3-gallate, a methyltransferase inhibitor. Treatment of CD4(+)CD25(+) Tregs with ox-LDL resulted in a 41% increase in the methylation of FOXP3, a 66% of reduction in FOXP3 mRNA expression, and an increase in the expression of DNA methyltransferase 3a as well as 3b.

CONCLUSIONS

Our data demonstrate that reduction in Treg cells is associated with ACS in atherosclerotic patients. Epigenetic suppression of FOXP3 might lead to down-regulation of Treg cells, and in turn increase the risk of ACS.

Immune cell dysfunction and inflammation in end-stage renal disease

Uraemia causes inflammation and reduces immune system function as evidenced by an increased risk of viral-associated cancers, increased susceptibility to infections and decreased vaccination responses in patients with end-stage renal disease (ESRD). The substantially increased risk of atherosclerosis in these patients is also probably related to uraemia-associated inflammation. Uraemia is associated with a reduction in the number and function of lymphoid cells, whereas numbers of myeloid cells in uraemic patients are normal or increased with increased production of inflammatory cytokines and reactive oxygen species. Similar to healthy elderly individuals, patients with ESRD have increased numbers of specific proinflammatory subsets of T cells and monocytes, suggesting the presence of premature immunological ageing in these patients. These cells might contribute to inflammation and destabilization of atherosclerotic plaques, and have, therefore, been identified as novel nonclassical cardiovascular risk factors. The cellular composition of the immune system does not normalize after successful kidney transplantation despite a rapid reduction in inflammation and oxidative stress. This finding suggests that premature ageing of the immune system in patients with ESRD might be related to a permanent skewing of the haematopoetic stem cell population towards myeloid-generating subsets, similar to that seen in healthy elderly individuals.

Depletion of FOXP3+ regulatory T cells promotes hypercholesterolemia and atherosclerosis

Atherosclerosis is a chronic inflammatory disease promoted by hyperlipidemia. Several studies support FOXP3-positive regulatory T cells (Tregs) as inhibitors of atherosclerosis; however, the mechanism underlying this protection remains elusive. To define the role of FOXP3-expressing Tregs in atherosclerosis, we used the DEREG mouse, which expresses the diphtheria toxin (DT) receptor under control of the Treg-specific Foxp3 promoter, allowing for specific ablation of FOXP3+ Tregs. Lethally irradiated, atherosclerosis-prone, low-density lipoprotein receptor-deficient (Ldlr(-/-)) mice received DEREG bone marrow and were injected with DT to eliminate FOXP3(+) Tregs. Depletion of Tregs caused a 2.1-fold increase in atherosclerosis without a concomitant increase in vascular inflammation. These mice also exhibited a 1.7-fold increase in plasma cholesterol and an atherogenic lipoprotein profile with increased levels of VLDL. Clearance of VLDL and chylomicron remnants was hampered, leading to accumulation of cholesterol-rich particles in the circulation. Functional and protein analyses complemented by gene expression array identified reduced protein expression of sortilin-1 in liver and increased plasma enzyme activity of lipoprotein lipase, hepatic lipase, and phospholipid transfer protein as mediators of the altered lipid phenotype. These results demonstrate that FOXP3(+) Tregs inhibit atherosclerosis by modulating lipoprotein metabolism.

The influence of vitamin A supplementation on Foxp3 and TGF-β gene expression in atherosclerotic patients

The aim of this study was to investigate the role of vitamin A in Foxp3 and TGF-β gene expression in atherosclerotic patients. Patients and healthy controls in the vitamin A group received 25,000 IU retinyl palmitate per day, while patients in the placebo group took one capsule of placebo per day for 4 months. Gene expressions of regulatory T cells were studied by real-time PCR. The levels of Foxp3 expression in phytohemagglutinin-activated cells were much higher in the patients who received vitamin A than in placebo-treated patients and healthy controls, while Foxp3 gene expression in oxidized low-density lipoprotein-activated cells showed no significant differences between all groups (p=0.357). A significant difference in the expression level of TGF-β gene in fresh cells was observed between patients and healthy controls (p=0.009). TGF-β gene expression in oxidized low-density lipoprotein-activated cells increased in all groups; however, these changes were not statistically significant (p=0.65); the changes obtained were 2.8-, 2.2- and 3.9-fold in the vitamin A, placebo, and control groups, respectively. Based on suppressing actions of regulatory T cells on effector T cells and findings that show that vitamin A has the effect of increasing expression of regulatory T cells, it can be concluded that supplementation with vitamin A in atherosclerotic patients may be effective in slowing disease progression.

T lymphocyte autoreactivity in inflammatory mechanisms regulating atherosclerosis

Atherosclerosis has been clearly demonstrated to be a chronic inflammatory disease of the arterial wall. Both cells of the innate and the acquired immune system, particularly monocytes and T lymphocytes, are implicated in the atherogenic process, producing different cytokines with pro- and anti-inflammatory effects. The majority of pathogenic T cells involved in atherosclerosis are of the Th1 profile, that has been correlated positively with coronary artery disease. Many studies conducted to evaluate the molecular factors responsible for the activation of T cells have demonstrated that the main antigenic targets in atherosclerosis are modified endogenous structures. These self-molecules activate autoimmune reactions mainly characterized by the production of Th1 cytokines, thus sustaining the inflammatory mechanisms involved in endothelial dysfunction and plaque development. In this paper we will summarize the different T-cell subsets involved in atherosclerosis and the best characterized autoantigens involved in cardiovascular inflammation.

Neutrophil-lymphocyte ratio as a predictor of major adverse cardiac events among diabetic population: a 4-year follow-up study

The neutrophil-lymphocyte ratio (NLR) is an inflammatory marker of major adverse cardiac events (MACEs) in both acute coronary syndromes and stable coronary artery disease. The use of NLR as a predictive tool for MACEs among diabetic patients has not been elucidated. An observational study included 338 diabetic patients followed at our clinic between 2007 and 2011. Patients were arranged into equal tertiles according to the 2007 NLR. The MACEs included acute myocardial infarction, coronary revascularization, and mortality. The lowest NLR tertile (NLR < 1.6) had fewer MACEs compared with the highest NLR tertile (NLR > 2.36; MACEs were 6 of 113 patients vs 24 of 112 patients, respectively; P < .0001). In a multivariate model, the adjusted hazard ratio of third NLR tertile compared with first NLR tertile was 2.8 (95% confidence interval 1.12-6.98, P = .027). The NLR is a significant independent predictor of MACEs in diabetic patients. Further studies with larger numbers are needed.

A genome-wide association study of inflammatory biomarker changes in response to fenofibrate treatment in the Genetics of Lipid Lowering Drug and Diet Network

OBJECTIVE

Despite the evidence in support of the anti-inflammatory and triglyceride-lowering effects of fenofibrate, little is known about genetic determinants of the observed heterogeneity in treatment response. This study provides the first genome-wide examination of fenofibrate effects on systemic inflammation.

METHODS

Biomarkers of inflammation were measured in participants of the Genetics of Lipid Lowering Drugs and Diet Network (n=1092) before and after a 3-week daily treatment with 160 mg of fenofibrate. Two inflammatory patterns [high-sensitivity C-reactive protein-interleukin-6 and monocyte chemoattractant protein-1-tumor necrosis factor (MCP1-TNF-α)] were derived using principal component analysis. Associations between single nucleotide polymorphisms on the Affymetrix 6.0 chip and phenotypes were assessed using mixed linear models, adjusted for age, sex, study center, and ancestry as fixed effects and pedigree as a random effect.

RESULTS

Before fenofibrate treatment, the strongest evidence for association was observed for polymorphisms near or within the IL2RA gene with the high-sensitivity C-reactive protein-interleukin-6 (IL6) pattern (rs7911500, P=5×10 and rs12722605, P=5×10). Associations of the MCP1-TNF-α pattern with loci in several biologically plausible genes [CYP4F8 (rs3764563), APBB1IP (rs1775246), COL13A1 (rs2683572), and COMMD10 (rs1396485)] approached genome-wide significance (P=3×10, 5×10, 6×10, and 7×10, respectively) before fenofibrate treatment. After fenofibrate treatment, the rs12722605 locus in IL2RA was also associated with the MCP1-TNF-α pattern (P=3×10). The analyses of individual biomarker response to fenofibrate did not yield genome-wide significant results, but the rs6517147 locus near the immunologically relevant IFNAR2 gene was suggestively associated with IL6 (P=7×10).

CONCLUSION

We have identified several novel biologically relevant loci associated with systemic inflammation before and after fenofibrate treatment.

Role of Peroxisome Proliferator-Activated Receptor-γ in Vascular Inflammation

Vascular inflammation plays a crucial role in atherosclerosis, and its regulation is important to prevent cerebrovascular and coronary artery disease. The inflammatory process in atherogenesis involves a variety of immune cells including monocytes/macrophages, lymphocytes, dendritic cells, and neutrophils, which all express peroxisome proliferator-activated receptor-γ (PPAR-γ). PPAR-γ is a nuclear receptor and transcription factor in the steroid superfamily and is known to be a key regulator of adipocyte differentiation. Increasing evidence from mainly experimental studies has demonstrated that PPAR-γ activation by endogenous and synthetic ligands is involved in lipid metabolism and anti-inflammatory activity. In addition, recent clinical studies have shown a beneficial effect of thiazolidinediones, synthetic PPAR-γ ligands, on cardiovascular disease beyond glycemic control. These results suggest that PPAR-γ activation is an important regulator in vascular inflammation and is expected to be a therapeutic target in the treatment of atherosclerotic complications. This paper reviews the recent findings of PPAR-γ involvement in vascular inflammation and the therapeutic potential of regulating the immune system in atherosclerosis.

Increased Th17 cell frequency concomitant with decreased Foxp3+ Treg cell frequency in the peripheral circulation of patients with carotid artery plaques

OBJECTIVE AND DESIGN

We investigated a possible imbalance between T helper (Th)17 and CD4+ CD25+ forkhead/winged helix transcription factor (Foxp3) T regulatory (Treg) cells in patients with carotid artery plaques.

MATERIAL OR SUBJECTS

From November 2009 to September 2010, we enrolled 126 males and 104 females with mean age 68.24 ± 6.71 years.

TREATMENT

Based on carotid artery sonography, the 230 subjects were categorized into three groups: plaque negative; stable plaques; and unstable plaques.

METHODS

Th17 and Treg cell frequencies, relevant plasma cytokines (IL-17, IL-6, IL-23, and TNF-α), and RORγt mRNA levels were determined.

RESULTS

Compared to plaque negative, Th17 cells, Th17-related cytokines (IL-17, IL-6, IL-23, and TNF-α), and RORγt mRNA levels were higher with stable plaques, and highest with unstable plaques. The opposite trend was found for Treg cells, Treg-related cytokines (IL-10 and TGF-β1), and Foxp3 mRNA. Th17 cell frequencies were significantly negatively correlated with Treg cell frequencies.

CONCLUSIONS

Our investigation demonstrated that there is a Th17/Treg functional imbalance in patients with unstable carotid atherosclerotic plaques. Th17 cells may promote atherogenesis, while Treg cells may have a protective role against atherosclerosis plaques. An imbalance of Th17/Treg cells may offer a new direction for the treatment of atherosclerosis.

Telomere length in cardiovascular disease: new challenges in measuring this marker of cardiovascular aging

Atherosclerosis is an age-related systemic disease characterized by systemic oxidative stress and low grade chronic inflammation. Various types of leukocytes play an important role within this process. Telomeres, the ends of chromosomes, shorten during each and every cell division and have therefore been regarded as a cellular clock. Telomere dysfunction has been implicated in aging and senescence, and shorter leukocyte telomere length (LTL) has been demonstrated to predict cardiovascular disease and mortality. However, although LTL can predict cardiovascular events in population studies, a number of factors have prevented its broad use as a surrogate end point, such as serum levels of LDL cholesterol. In this article we will provide an overview of telomere biology and telomere dynamics of different leukocyte populations, and we will also discuss pitfalls in the methodology of LTL quantification, in context with landmark studies, which measured LTL in cardiovascular disease. Finally, we will attempt to critically assess and explain the shortcomings of LTL as a biomarker and identify further research avenues that require further investigation before telomere length can be implemented as an individual biomarker for cardiovascular aging. From this it becomes evident that LTL can be susceptible to methodological errors affecting longitudinal reproducibility. LTL is generally confounded at least by genetic factors, population variation and leukocyte composition.

Fenofibrate enhances the in vitro differentiation of foxp3(+) regulatory T cells in mice

Foxp3⁺ regulatory T cells (Tregs) play a critical role in maintaining immune self-tolerance. Reduced number and activity of Tregs are usually found in autoimmune and inflammatory diseases, and enhancing the differentiation of Tregs may be a promising therapeutic strategy. Some reports suggested an anti-inflammatory and anti-autoimmune potential for fenofibrate, a hypolipidemic drug used worldwide, whose lipid effects are mediated by the activation of peroxisome proliferator-activated receptor α (PPARα). In the present paper, we found that fenofibrate dose-dependently increased transforming growth factor-β and interleukin-2-induced Treg differentiation in vitro, by 1.96-fold from 0 to 20 μM (12.59 ± 1.34% to 24.69 ± 3.03%, P < 0.05). Other PPARα activators, WY14643 (100 μM), gemfibrozil (50 μM), and bezafibrate (30 μM), could not enhance Treg differentiation. In addition, PPARα could not upregulate the promoter activity of the Treg-specific transcription factor Foxp3. Fenofibrate might exert its function by enhancing Smad3 phosphorylation, a critical signal in Treg differentiation, via Akt suppression. Our work reveals a new PPARα independent anti-inflammatory mechanism of fenofibrate in up-regulating mouse Treg differentiation.

Role of adaptive immunity in alcoholic liver disease

Stimulation of innate immunity is increasingly recognized to play an important role in the pathogenesis of alcoholic liver disease (ALD), while the contribution of adaptive immunity has received less attention. Clinical and experimental data show the involvement of Th-1 and Th-17 T-lymphocytes in alcoholic hepatitis. Nonetheless, the mechanisms by which alcohol triggers adaptive immunity are still incompletely characterized. Patients with advanced ALD have circulating IgG and T-lymphocytes recognizing epitopes derived from protein modification by hydroxyethyl free radicals and end products of lipid-peroxidation. High titers of IgG against lipid peroxidation-derived antigens are associated with an increased hepatic production of proinflammatory cytokines/chemokines. Moreover, the same antigens favor the breaking of self-tolerance towards liver constituents. In particular, autoantibodies against cytochrome P4502E1 (CYP2E1) are evident in a subset of ALD patients. Altogether these results suggest that allo- and autoimmune reactions triggered by oxidative stress might contribute to hepatic inflammation during the progression of ALD.

Orally Administered Eicosapentaenoic Acid Induces Rapid Regression of Atherosclerosis Via Modulating the Phenotype of Dendritic Cells in LDL Receptor-Deficient Mice

Objective—

Eicosapentaenoic acid (EPA) has been shown to have beneficial effects on cardiovascular diseases, although the precise mechanism is unknown. We investigated the effect of EPA on the regression of atherosclerosis.

Methods and Results—

LDL-receptor–deficient mice were fed a high-cholesterol diet for 8 weeks to build up aortic sinus atherosclerotic lesions and then were fed a normal diet with or without 5% EPA for 4 weeks. Atherosclerotic lesions were histologically assessed, and immunologic assays were performed. EPA treatment significantly regressed atherosclerosis (−22.7%, P <0.05) and decreased the content of macrophages, CD4 + T cells, and dendritic cells (DCs) in atherosclerotic lesions, though only changing the chow never induced the regression. Flow cytometric analysis revealed that EPA increased immature DCs (CD11c + CD80 − CD86 − ), increased the indoleamine 2,3-dioxygenase (IDO) in DCs, and decreased the number of CD4 + T cells. In the presence of the IDO inhibitor, the beneficial effects of EPA on regression were inhibited, suggesting that the effect of EPA was mainly mediated through IDO.

Conclusion—

In addition to lowering plasma cholesterol, EPA regressed atherosclerosis probably due to modulation of DC phenotype and reduction in T cell numbers. The present findings might partly explain the beneficial effects of EPA in clinics and support clinical evidence.

Tumor necrosis factor superfamily molecules in acute coronary syndromes

Accumulating evidence suggests that inflammatory pathways play an essential role in all stages of atherogenesis. Inflammatory processes are not only involved in plaque progression, but seem also to play a critical role in plaque rupture. Members of the tumor necrosis factor (TNF) superfamiliy are potent regulators of inflammation and cell survival and consist of 20 ligands that signal through 29 different receptors. Several lines of evidence suggest that TNF-related molecules are involved in the development of acute coronary syndromes (ACS). Most, convincing evidence exists for CD40 ligand-CD40 interaction, but several other members of the TNF superfamily seem also to be involved in this immune-mediated promotion of plaque instability, including LIGHT, receptor activator of nuclear factor κB ligand, and TNF-α. These plaque destabilization pathways involve the bidirectional interaction between platelets and endothelial cells/monocytes, activation of vascular smooth muscle cells, and co-stimulatory effects on T cells, promoting inflammation, thrombus formation, matrix degradation, and apoptosis. TNF-related pathways could contribute to the non-resolving inflammation that characterizes atherosclerosis, representing pathogenic loops that are operating during plaque rupture and the development of ACS. These TNF-related molecules could also represent attractive new targets for therapy in this disorder.

An antioxidant probiotic reduces postprandial lipemia and oxidative stress

Reducing postprandial oxidative stress (OxS), decreasing postprandial blood triglyceride level (TG) and improving lipoprotein status is likely to have a preventive impact on the development of cardiovascular disease (CVD). Previously we have shown that the antioxidant probiotic Lactobacillus fermentum ME-3 (DSM14241) is characterized by antiatherogenic effects. This randomized double-blind placebo-controlled study evaluated the influence of kefir enriched with an antioxidative probiotic L. fermentum ME-3 (LfKef) on postprandial OxS, blood TG response and lipoprotein status. 100 clinically healthy subjects were recruited into the study. Blood parameters of postprandial OxS, TG and lipoprotein status were determined by oxidized LDL, baseline diene conjugation in LDL (BDC-LDL), oxidized LDL complex with beta-2 glycoprotein (Beta2-GPI-oxLDL), paraoxonase (PON) activity, LDL-Chol, HDL-Chol and TG. To evaluate general body postprandial OxS-load we measured 8-isoprostanes (8-EPI) in the urine. Consumption of LfKef significantly reduced the postprandial level of oxidized LDL, BDC-LDL, Beta2-GPI-oxLDL, urinary 8-isoprostanes and postprandial TG and caused a significant increase in HDL-Chol and PON activity. This is the first evidence that kefir enriched with an antioxidant probiotic may have a positive effect on both postprandial OxS and TG response as well as on lipoprotein status.

Natural regulatory T cells control coronary arteriolar endothelial dysfunction in hypertensive mice

Coronary artery disease in patients with hypertension is increasing worldwide and leads to severe cardiovascular complications. The cellular and molecular mechanisms that underlie this pathologic condition are not well understood. Experimental and clinical research indicates that immune cells and inflammation play a central role in the pathogenesis of cardiovascular diseases. Recently, it has been reported that CD4(+)CD25(+) regulatory T cells (Tregs) regulate heart fibrosis in hypertension. In this study, we determined the role of Tregs in coronary arteriolar endothelial dysfunction in angiotensin II-dependent hypertensive mice. Mice infused with angiotensin II had significantly increased blood pressure, as determined using telemetry, and apoptotic Treg numbers, as measured using flow cytometry. The mice displayed inflammation, assessed by macrophage activation/infiltration into coronary arterioles and the heart, and increased local tumor necrosis factor-α release, which participates in reduced coronary arteriolar endothelial-dependent relaxation in response to acetylcholine using an arteriograph. Hypertensive mice injected with Tregs isolated from control mice had significantly reduced macrophage activation and infiltration, reduced tumor necrosis factor-α release, and improved coronary arteriolar endothelium-dependent relaxation. Our novel data indicate that Tregs are important in the development of coronary arteriolar endothelial dysfunction in hypertension. These results suggest a new direction in the investigation of vascular disease in hypertension and could lead to a therapeutic strategy that involves immune system modulation using Tregs.

Identification of IP-10 and IL-5 as proteins differentially expressed in human complicated and uncomplicated carotid atherosclerotic plaques

Inflammation plays a crucial role in the development and progression of atherosclerotic plaques. The aim of this study is to compare culture supernatants from uncomplicated and complicated carotid atherosclerotic plaques by a multiplex approach, to assess the molecular mediators associated with a plaque complicated phenotype. Atherosclerotic plaques were obtained from 17 patients undergoing carotid endarterectomy. Supernatants from plaque cultures were evaluated by Bio-Plex cytokine assay to determine 27 pro- and anti-inflammatory cytokines, chemokines and growth factors. Complicated plaques secreted higher levels of IP-10 (p = 0.027) and lower levels of IL-5 (p = 0.045) than did uncomplicated ones. Distinctive secretory patterns of cytokines, chemokines and growth factors were present in the two types of plaque. Our study identifies IP-10 and IL-5 as proteins differentiating complicated and uncomplicated plaques from human carotid arteries and provides new insights into the interplay of molecular mediators with atherosclerotic plaque progression.

Neuropeptides: keeping the balance between pathogen immunity and immune tolerance

Various neuropeptides have emerged recently as potent immunomodulatory factors with potential for their therapeutic use in immune disorders. Here we highlight the most recent data relevant in the field and we offer our opinion on how neuropeptide therapy might impact clinical immune diseases, and the challenges in this field that must be overcome before achieving medical progress. We also review recent reports describing the antimicrobial effects showed by some neuropeptides and the therapeutic, physiological, and evolutionary consequences of this new finding. Finally, we discuss how a physiologically functional neuropeptide system contributes to general health and how neuropeptides educate our immune system to be tolerant.

Th 17 cells interplay with Foxp3+ Tregs in regulation of inflammation and autoimmunity

T helper 17 cells (Th17) are a new CD4+ T helper subset that has been implicated in inflammatory and autoimmune diseases. Th17, along with CD4(+)CD25(high) Foxp3(+) regulatory T cells (Tregs) and other new T helper subsets, have expanded the Th1-Th2 paradigm. Although this new eight-subset paradigm significantly improved our understanding on the differentiation and regulation of CD4+ T helper subsets, many questions remain to be answered. Here we will briefly review the following issues: a) Old Th1-Th2 paradigm versus new multi-subset paradigm; b) Structural features of IL-17 family cytokines; c) Th17 cells; d) Effects of IL-17 on various cell types and tissues; e) IL-17 receptor and signaling pathways; f) Th17-mediated inflammations; and g) Protective mechanisms of IL-17 in infections. Lastly, we will examine the interactions of Th17 and Treg in autoimmune diseases and inflammation: Th17 cells interplay with Tregs. Regulation of autoimmunity and inflammation lies in the interplays of the different T helper subsets, therefore, better understanding of these subsets' interactions would greatly improve our approaches in developing therapy to combat inflammatory and autoimmune diseases.

Effect of 3 months of doxazosin therapy on T-cell subsets in type 2 diabetic patients

Doxazosin, an alpha(1)-adrenergic receptor inhibitor, is commonly administered to patients with type 2 diabetes, hypertension and nephropathy. The impact of 3 months' doxazosin therapy on the prevalence of activated and regulatory T lymphocytes was analysed in this pilot study of men with type 2 diabetes (n = 10) who received doxazosin 4 mg/day in addition to their ongoing therapy. The prevalence of CD4(+), CD8(+), CD25(+) and CD69(+) cells at baseline and after 3 months of add-on therapy was determined. The prevalence of regulatory T-cells was detected by two different approaches: forkhead box P3 (FoxP3) positivity; and the number of CD4(+)CD25(+high) cells. During 3 months of doxazosin therapy, patients' blood pressure, blood glucose control and lipid profiles all significantly improved. Simultaneously, the prevalence of activated T-cells (CD4(+)CD69(+) and CD8(+)CD69(+) cells) decreased, whereas that of regulatory T-cells increased. These results indicate an immunomodulatory action of doxazosin in type 2 diabetic patients.

Immunomodulation of vascular diseases: atherosclerosis and autoimmunity

The autoimmune disease atherosclerosis contributes to several vascular complications. Besides vascular cells, inflammatory cells occur prominently in atherosclerotic lesions; lymphocytes play a detrimental role in the initiation and progression of this common vascular disease. Recent discoveries have led to the identification of several important lymphocyte types within the atherosclerotic lesions. However, peripheral lymphocytes and those in the lymphoid organs both figure critically in the regulation of atherosclerotic lesion growth. Although the concept of atherosclerosis as an autoimmune disease is well known, the ways in which autoantigens and autoantibodies contribute to atherogenesis in human or even in animal models remains largely unknown. For example, autoantigen immunisation can either promote or attenuate atherogenesis in animals, depending on the antigen types and the routes and carriers of immunisation. This article summarises recent findings regarding lesion inflammatory cell types, autoantigens and autoantibody isotypes that can affect the initiation and progression of atherosclerosis from both human and animal studies.