Atherosclerosis as an autoimmune disease: an update

Immunomodulation for accelerated atherosclerosis in rheumatoid arthritis and systemic lupus erythematosus

In the last decades, consisting evidence supported a close relationship between both innate and adaptive immune systems and the accelerated cardiovascular (CV) disease characterizing autoimmune diseases, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Indeed, several cell lines involved in the pathogenesis of these autoimmune diseases, such as macrophages and dendritic cells, as well as different T and B lymphocyte subsets, and inflammatory cytokines, have been demonstrated to be directly involved in the mechanisms underlying early atherosclerotic arterial wall damage. Traditional CV risk factors play a concomitant role but do not sufficiently account for the increased prevalence of CV disease in these patients. Indeed, the pathophysiological link between RA and SLE and atherosclerosis is based on complex inflammatory pathways that interconnect these conditions and may explain the significant morbidity and mortality rates demonstrated in these patients, with consequent significant negative effects on quality of life and long-term survival. Consequently, it is intriguing to hypothesize that immunosuppressive drugs commonly used in the treatment of these pathologies may also exert an immunomodulatory and anti-inflammatory effect in mitigating the atherosclerotic damage that has been demonstrated to occur early in the initial stages of the disease. Recognizing risk factors, predicting occurrences and early intervention to prevent CV disease development have emerged as critical objectives in RA and SLE treatment. In this review, we aimed to provide an updated overview of the atherogenic effects exerted by the immune and inflammatory pathways involved in the pathogenesis of RA and SLE. Moreover, we examined the available evidence which may support the potential effects of immunosuppressive therapies in reducing CV damage and, consequently, CV disease risk in these patients.

Immunosenescence, Inflammaging, and Frailty: Role of Myeloid Cells in Age-Related Diseases

The immune system is the central regulator of tissue homeostasis, ensuring tissue regeneration and protection against both pathogens and the neoformation of cancer cells. Its proper functioning requires homeostatic properties, which are maintained by an adequate balance of myeloid and lymphoid responses. Aging progressively undermines this ability and compromises the correct activation of immune responses, as well as the resolution of the inflammatory response. A subclinical syndrome of "homeostatic frailty" appears as a distinctive trait of the elderly, which predisposes to immune debilitation and chronic low-grade inflammation (inflammaging), causing the uncontrolled development of chronic and degenerative diseases. The innate immune compartment, in particular, undergoes to a sequela of age-dependent functional alterations, encompassing steps of myeloid progenitor differentiation and altered responses to endogenous and exogenous threats. Here, we will review the age-dependent evolution of myeloid populations, as well as their impact on frailty and diseases of the elderly.

Fusobacterium nucleatum and its associated systemic diseases: epidemiologic studies and possible mechanisms

Background

Fusobacterium nucleatum (F. nucleatum) is an anaerobic oral commensal and the major coaggregation bridge organism linking early and late colonisers. In recent years, a large number of studies suggest that F. nucleatum is closely related to the development of various systemic diseases, such as cardiovascular diseases, adverse pregnancy outcomes, inflammatory bowel diseases, cancer, Alzheimer's disease, respiratory infection, rheumatoid arthritis, etc.

Objective

To review the effect of F. nucleatum on systemic diseases and its possible pathogenesis and to open new avenues for prevention and treatment of F. nucleatum-associated systemic diseases.

Design

The research included every article published up to July 2022 featuring the keywords 'Systemic diseases' OR 'Atherosclerotic cardiovascular diseases' OR 'Atherosclerosis' OR 'Adverse pregnancy outcomes' OR 'Inflammatory bowel disease' OR 'Ulcerative colitis' OR 'Crohn’s disease' OR 'Cancers' OR 'Oral squamous cell carcinomas' OR 'Gastrointestinal cancers' OR 'Colorectal cancer' OR 'Breast cancer' OR 'Genitourinary cancers' OR 'Alzheimer’s disease ' OR 'Rheumatoid arthritis' OR 'Respiratory diseases' AND 'Fusobacterium nucleatum' OR 'Periodontal pathogen' OR 'Oral microbiota' OR 'Porphyromonas gingivalis' and was conducted in the major medical databases.

Results

F. nucleatum can induce immune response and inflammation in the body through direct or indirect pathways, and thus affect the occurrence and development of systemic diseases. Only by continuing to investigate the pathogenic lifestyles of F. nucleatum will we discover the divergent pathways that may be leveraged for diagnostic, preventive and therapeutic purposes.

Opinion: On the Way towards the New Paradigm of Atherosclerosis

Atherosclerosis is a multicausal disease characterized by the formation of cholesterol-containing plaque in the pronounced intima nearest to the heart's elastic-type arteries that have high levels of blood circulation. Plaques are formed due to arterial pressure-induced damage to the endothelium in areas of turbulent blood flow. It is found in the majority of the Western population, including young people. This denies the monogenic mechanism of atherogenesis. In 1988, Orekhov et al. and Kawai et al. discovered that the presence of atherogenic (modified, including oxidized ones) LDLs is necessary for atherogenesis. On the basis of our discovery, suggesting that the overloading of enterocytes with lipids could lead to the formation of modified LDLs, we proposed a new hypothesis explaining the main factors of atherogenesis. Indeed, when endothelial cells are damaged and then pass through the G2 phase of their cell cycle they secrete proteins into their basement membrane. This leads to thickening of the basement membrane and increases its affinity to LDL especially for modified ones. When the enterocyte transcytosis pathway is overloaded with fat, very large chylomicrons are formed, which have few sialic acids, circulate in the blood for a long time, undergo oxidation, and can induce the production of autoantibodies. It is the sialic acids that shield the short forks of the polysaccharide chains to which autoantibodies are produced. Here, these data are evaluated from the point of view of our new model.

The Pathophysiological Role of Heat Shock Response in Autoimmunity: A Literature Review

Within the last two decades, there has been increasing evidence that heat-shock proteins can have a differential influence on the immune system. They can either provoke or ameliorate immune responses. This review focuses on outlining the stimulatory as well as the inhibitory effects of heat-shock proteins 27, 40, 70, 65, 60, and 90 in experimental and clinical autoimmune settings.

Potential Benefits of Flavonoids on the Progression of Atherosclerosis by Their Effect on Vascular Smooth Muscle Excitability

Flavonoids are a group of secondary metabolites derived from plant-based foods, and they offer many health benefits in different stages of several diseases. This review will focus on their effects on ion channels expressed in vascular smooth muscle during atherosclerosis. Since ion channels can be regulated by redox potential, it is expected that during the onset of oxidative stress-related diseases, ion channels present changes in their conductive activity, impacting the progression of the disease. A typical oxidative stress-related condition is atherosclerosis, which involves the dysfunction of vascular smooth muscle. We aim to present the state of the art on how redox potential affects vascular smooth muscle ion channel function and summarize if the benefits observed in this disease by using flavonoids involve restoring the ion channel activity.

Heat shock protein 60 and cardiovascular diseases: An intricate love-hate story

Cardiovascular diseases (CVDs) are the result of complex pathophysiological processes in the tissues comprising the heart and blood vessels. Inflammation is the main culprit for the development of cardiovascular dysfunction, and it may be traced to cellular stress events including apoptosis, oxidative and shear stress, and cellular and humoral immune responses, all of which impair the system's structure and function. An intracellular chaperone, heat shock protein 60 (HSP60) is an intriguing example of a protein that may both be an ally and a foe for cardiovascular homeostasis; on one hand providing protection against cellular injury, and on the other triggering damaging responses through innate and adaptive immunity. In this review we will discuss the functions of HSP60 and its effects on cells and the immune system regulation, only to later address its implications in the development and progression of CVD. Lastly, we summarize the outcome of various studies targeting HSP60 as a potential therapeutic strategy for cardiovascular and other diseases.

Low frequency of IL-10+ B cells in patients with atherosclerosis is related with inflammatory condition

Background and aims

B cells involvement in animal models of atherosclerosis has been unequivocally established. However, the role of these cells in patients with atherosclerosis is almost unknown. Besides the production of antibodies, B cells can also exhibit regulatory functions mainly through IL-10. Here, we characterized human B cell subsets, their production of IL-10 in patients with atherosclerosis and their potential association with inflammation.

Methods

Patients with confirmed atherosclerotic events and controls with low cardiovascular risk were included. B cells subsets were determined in mononuclear cells (PBMC) using flow cytometry. PBMC were cultured ex vivo (5 h) and in vitro (48 h) to determine IL-10⁺ B cells and in some cases TNF-α⁺ and IFN-γ⁺ CD4⁺ T cells. The inflammatory state of the participants was determined through high sensitivity C reactive protein levels.

Results

Increase in percentage and number of plasmablasts was observed in patients with atherosclerosis compared with controls. A decreased frequency of IL-10⁺ B cells was observed in patients, both in ex vivo and in vitro cultures. This decrease was detected in transitional, memory, and plasmablast subsets. Interestingly, the reduction of IL-10⁺ B cells negatively and significantly correlated with the inflammatory condition of the studied subjects and associated with an increased frequency of TNF-α⁺ and IFN-γ⁺ CD4⁺ T cells. The blockade of IL-10R did not show further effect in T cells activation.

Conclusions

There is an association between the inflammatory state and a reduction of IL-10⁺ B cells that could contribute to the development of atherosclerosis.

Correlation between HSP-72 Expression and IL-8 Secretion in Human Mesothelial Cells

Background

Cytotoxicity of peritoneal dialysis fluid (PDF) and peritoneal inflammation are currently regarded as the two major culprits for chronic mesothelial injury and peritoneal membrane failure. In this study, we correlated induction of HSP-72, as a marker of the cellular stress response, to secretion of IL-8, as a marker for pro-inflammatory cytokines, in mesothelial cells upon sublethal PDF exposure.

Methods

Primary omental cell cultures of human mesothelial cells were subjected to sublethal PDF exposure times (CAPD2, Fresenius, Germany). At the end of a 24 hour recovery period, induction of HSP-72 in the cell homogenate and IL-8 secretion in the supernatant was assessed by immunodensitometry and ELISA, respectively.

Results

PDF exposure times from 15 min to 60 min resulted in progressively increased HSP-72 expression levels (267 vs 320 vs 419% of controls, p<0.05 vs controls) as well as increased IL-8 secretion (323 vs 528 vs 549% of controls, p<0.05 vs controls) with full cell viability (MTT unchanged to control). HSP-72 expression was statistically significantly correlated with IL-8 secretion. Conclusions: The significant correlation between HSP-72 expression and IL-8 secretion suggests that the regulation of pro-inflammatory pathways in mesothelial cells exposed to PDF may represent an integral part of their stress response. Future studies to investigate the cellular regulatory mechanism involved are warranted.

Human T cell immunosenescence and inflammation in aging

The aging process is driven by a finite number of inter-related mechanisms that ultimately lead to the emergence of characteristic phenotypes, including increased susceptibility to multiple chronic diseases, disability, and death. New assays and analytical tools have become available that start to unravel some of these mechanisms. A prevailing view is that aging leads to an imbalance between stressors and stress-buffering mechanisms that causes loss of compensatory reserve and accumulation of unrepaired damage. Central to this paradigm are changes in the immune system and the chronic low-grade proinflammatory state that affect many older individuals, even when they are apparently healthy and free of risk factors. Independent of chronological age, high circulating levels of proinflammatory markers are associated with a high risk of multiple adverse health outcomes in older persons. In this review, we discuss current theories about causes and consequences of the proinflammatory state of aging, with a focus on changes in T cell function. We examine the role of NF-κB activation and its dysregulation and how NF-κB activity differs among subgroups of T cells. We explore emerging hypotheses about immunosenescence and changes in T cell behavior with age, including consideration of the T cell antigen receptor and regulatory T cells (T_regs). We conclude by illustrating how research using advanced technology is uncovering clues at the core of inflammation and aging. Some of the preliminary work in this field is already improving our understanding of the complex mechanisms by which immunosenescence of T cells is intertwined during human aging.

Quantitative proteomic analysis of extracellular matrix extracted from mono- and dual-species biofilms of Fusobacterium nucleatum and Porphyromonas gingivalis

The Gram-negative bacteria Fusobacterium nucleatum and Porphyromonas gingivalis are members of a complex dental biofilm associated with periodontal disease. In this study, we cultured F. nucleatum and P. gingivalis as mono- and dual-species biofilms, and analyzed the protein composition of the biofilms extracellular polymeric matrix (EPM) by high-resolution liquid chromatography-tandem mass spectrometry. Label-free quantitative proteomic analysis was used for identification of proteins and sequence-based functional characterization for their classification and prediction of possible roles in EPM. We identified 542, 93 and 280 proteins in the matrix of F. nucleatum, P. gingivalis, and the dual-species biofilm, respectively. Nearly 70% of all EPM proteins in the dual-species biofilm originated from F. nucleatum, and a majority of these were cytoplasmic proteins, suggesting an enhanced lysis of F. nucleatum cells. The proteomic analysis also indicated an interaction between the two species: 22 F. nucleatum proteins showed differential levels between the mono and dual-species EPMs, and 11 proteins (8 and 3 from F. nucleatum and P. gingivalis, respectively) were exclusively detected in the dual-species EPM. Oxidoreductases and chaperones were among the most abundant proteins identified in all three EPMs. The biofilm matrices in addition contained several known and hypothetical virulence proteins, which can mediate adhesion to the host cells and disintegration of the periodontal tissues. This study demonstrated that the biofilm matrix of two important periodontal pathogens consists of a multitude of proteins whose amounts and functionalities vary largely. Relatively high levels of several of the detected proteins might facilitate their potential use as targets for the inhibition of biofilm development.

Epitope Mapping of Porphyromonas gingivalis Heat-shock Protein and Human Heat-shock Protein in Human Atherosclerosis

To identify T- and/or cross-reactive B-cell epitopes of P. gingivalis and human heat-shock protein (HSP)60 in atherosclerosis patients, we synthesized 104 overlapping synthetic peptides spanning whole molecules of P. gingivalis HSP60 and human HSP60, respectively. T-cell epitopes of P. gingivalis HSP were identified with the use of previously established P. gingivalis HSP-reactive T-cell lines. B-cell epitopes of P. gingivalis HSP60 and human HSP60 were identified by the use of patients’ sera. Anti- P. gingivalis, anti- P. gingivalis HSP60, or anti-human HSP60 IgG antibody titers were higher in the atherosclerosis patients compared with the healthy subjects. Five immunodominant peptides of P. gingivalis HSP60, identified as T-cell epitopes, were also found to be B-cell epitopes. Moreover, 6 cross-reactive B-cell epitopes of human HSP60 were identified. It was concluded that P. gingivalis HSP60 might be involved in the immunoregulatory process of atherosclerosis, with common T- and/or B-cell epitope specificities and with cross-reactivity with human HSP60.

Nonorgan specific autoantibodies and heart damage

Heart damage, mediated by different autoantibodies can involve several anatomical heart structures: valves, arteries, conduction tissue. Verrucous endocarditis is frequently reported in patients with antiphospholipid syndrome (APS) with or without systemic lupus erythematosus (SLE), particularly if they suffer from central nervous system involvement. Antiphospholipid antibodies (aPL) were shown deposited at subendothelial level of the affected valves. According to several in vitro and in vivo experimental models, aPL, anti-oxidized LDL (oxLDL), anti-heat shock protein 65 (HSP65) and anti-endothelial cells antibodies (AECA) seem to be involved in the pathogenesis of the atherosclerosis phenomena described in systemic autoimmune disease and vasculitis. However, the observation of the association of the same antibodies with clinical and subclinical atherosclerosis in patients is still controversial. The children of anti-Ro/SSA positive mothers can be affected by the congenital heart block. Anti Ro/SS-A antibodies play a major pathogenic role in affecting the heart conduction tissue in this rare condition.

System-wide assembly of pathways and modules hierarchically reveal metabolic mechanism of cerebral ischemia

The relationship between cerebral ischemia and metabolic disorders is poorly understood, which is partly due to the lack of comparative fusing data for larger complete systems and to the complexity of metabolic cascade reactions. Based on the fusing maps of comprehensive serum metabolome, fatty acid and amino acid profiling, we identified 35 potential metabolic biomarkers for ischemic stroke. Our analyses revealed 8 significantly altered pathways by MetPA (Metabolomics Pathway Analysis, impact score >0.10) and 15 significantly rewired modules in a complex ischemic network using the Markov clustering (MCL) method; all of these pathways became more homologous as the number of overlapping nodes was increased. We then detected 24 extensive pathways based on the total modular nodes from the network analysis, 12 of which were new discovery pathways. We provided a new perspective from the viewpoint of abnormal metabolites for the overall study of ischemic stroke as well as a new method to simplify the network analysis by selecting the more closely connected edges and nodes to build a module map of stroke.

Infections and autoimmunity: role of human cytomegalovirus in autoimmune endothelial cell damage

Molecular mimicry between infectious agents and normal human host cell proteins represents one of the possible mechanisms responsible for autoimmunity. Among infectious agents, human cytomegalovirus (HCMV) is an ideal candidate for involvement in autoimmune disorders because of its lifelong persistence through periods of reactivation and latency and because of the extensive manipulation of innate and adaptive immunity. HCMV has been implicated in the pathogenesis of vascular damage in systemic sclerosis (SSc) and atherosclerosis. Based on our data, which demonstrate a cause-and-effect relationship between HCMV and endothelial cell aggression in SSc and atherosclerosis, we propose that immune responses to particular HCMV proteins may result in autoaggression through a mechanism of molecular mimicry of normally expressed endothelial cell surface molecules.

T cells in atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the artery wall. Atherosclerotic lesions contain monocytes, macrophages, smooth muscle cells and T lymphocytes. Here, we review the role of T-lymphocyte subsets in atherosclerosis. Among CD4⁺T cells, T(h)1 cells are pro-atherogenic, T(reg) cells are athero-protective and the role of T(h)2 and T(h)17 cells remains unclear. The role of follicular helper T cells in atherosclerosis remains unknown, as is the role of CD8⁺T cells. NKT cells bind glycolipid antigens and exert a pro-atherogenic role. The antigen specificity of T-cell responses in atherosclerosis is poorly understood. In order to enable antigen-specific prevention or therapy, a better understanding of these mechanisms is needed.

Mycobacterium leprae Hsp65 administration reduces the lifespan of aged high antibody producer mice

BACKGROUND

Aging process may result in immune modifications that lead to disruption of innate and acquired immunity mechanisms that may induce chronic-degenerative events. The heat shock proteins (Hsp), phylogeneticaly conserved among organisms, present as main function the ability of folding and refolding proteins, but they also are associated with chronic-degenerative disorders. Here were evaluated the role of M. leprae native Hsp65 (WT) and its point-mutated (K409A) on survival and anti-DNA and anti-Hsp65 antibody production of aged genetically selected mice for high (HIII) and low (LIII) antibody production; data from 120- and 270-days old mice (named "adult" or "aged", respectively) were compared.

RESULTS

WT Hsp65 administration induces reduction in the mean survival time of adult and aged female HIII mice, this effect being stronger in aged individuals. Surprisingly, the native protein administration increased the survival of aged female LIII when compared to K409A and control groups. No survival differences were observed in aged male mice after Hsp65 proteins inoculation. We observed increase in IgG1 anti-Hsp65 in WT and K409A aged HIII female mice groups and no marked changes in the anti-DNA (adult and aged HIII) and anti-Hsp65 IgG1 or IgG2a isotypes production in adult HIII female and aged male mice. LIII male mice presented increased anti-DNA and anti-Hsp65 IgG2a isotype production after WT or K409A injection, and LIII female groups showed no alterations.

CONCLUSIONS

The results revealed that the WT Hsp65 interferes with survival of aged HIII female mice without involvement of a remarkable IgG1 and IgG2a anti-DNA and anti-Hsp65 antibodies production. The deleterious effects of Hsp65 on survival time in aged HIII female mice could be linked to a gender-effect and are in agreement with those previously reported in lupus-prone mice.

Periodontitis as a risk factor of atherosclerosis

Over the last two decades, the amount of evidence corroborating an association between dental plaque bacteria and coronary diseases that develop as a result of atherosclerosis has increased. These findings have brought a new aspect to the etiology of the disease. There are several mechanisms by which dental plaque bacteria may initiate or worsen atherosclerotic processes: activation of innate immunity, bacteremia related to dental treatment, and direct involvement of mediators activated by dental plaque and involvement of cytokines and heat shock proteins from dental plaque bacteria. There are common predisposing factors which influence both periodontitis and atherosclerosis. Both diseases can be initiated in early childhood, although the first symptoms may not appear until adulthood. The formation of lipid stripes has been reported in 10-year-old children and the increased prevalence of obesity in children and adolescents is a risk factor contributing to lipid stripes development. Endothelium damage caused by the formation of lipid stripes in early childhood may lead to bacteria penetrating into blood circulation after oral cavity procedures for children as well as for patients with aggressive and chronic periodontitis.

Antibodies against Hsp60 and Hsp65 in the sera of women with ovarian cancer

Background

The aim of this study was to evaluate the concentrations of IgG antibodies against Hsp60 and Hsp65 in sera of patients with ovarian cancer at various stages of clinical progress and for different histopathological types of disease.

Methods

Serum samples from 149 patients with ovarian carcinoma and 80 healthy women were investigated. The concentrations of anti-Hsp60 and anti-Hsp65 antibodies were determined using the enzyme-linked immunosorbent assay technique.

Results

The mean concentrations of anti-Hsp60 and anti-Hsp65 antibodies in the patients with ovarian cancer did not differ significantly from the mean levels in healthy women. Analysis in relation to the clinical progression stage showed that the concentrations of these antibodies were higher when the neoplastic process was less advanced and at early stages significantly higher than in control group. Mean concentrations of both antibodies were not significantly different in relation to the histological type of the ovarian cancer. The use of chemotherapy as a primary anticancer treatment did not cause a significant change in the concentration of anti-Hsp60 antibodies, but the mean level of anti-Hsp65 after this treatment was significantly higher than in control group.

Conclusions

The immunological response to Hsp60/65 is increased in early clinical stages of ovarian cancer and the level of anti-hsp60/65 antibodies may be then a helpful diagnostic marker. Even antibodies against highly homologous Hsps may be cross-reactive only partially and differ by some functional properties.

Atheroprotective Vaccination with MHC-II Restricted Peptides from ApoB-100

BACKGROUND

Subsets of CD4(+) T-cells have been proposed to serve differential roles in the development of atherosclerosis. Some T-cell types are atherogenic (T-helper type 1), while others are thought to be protective (regulatory T-cells). Lineage commitment toward one type of helper T-cell versus another is strongly influenced by the inflammatory context in which antigens are recognized. Immunization of atherosclerosis-prone mice with low-density lipoprotein (LDL) or its oxidized derivative (ox-LDL) is known to be atheroprotective. However, the antigen specificity of the T-cells induced by vaccination and the mechanism of protection are not known.

METHODS

Identification of two peptide fragments (ApoB3501-3516 and ApoB978-993) from murine ApoB-100 was facilitated using I-Ab prediction models, and their binding to I-Ab determined. Utilizing a vaccination scheme based on complete and incomplete Freund's adjuvant (CFA and IFA) [1 × CFA + 4 × IFA], we immunized Apoe(-/-)mice with ApoB3501-3516 or ApoB978-993 emulsified in CFA once and subsequently boosted in IFA four times over 15 weeks. Spleens, lymph nodes, and aortas were harvested and evaluated by flow cytometry and real time RT-PCR. Total atherosclerotic plaque burden was determined by aortic pinning and by aortic root histology.

RESULTS

Mice immunized with ApoB3501-3516 or ApoB978-993 demonstrated 40% reduction in overall plaque burden when compared to adjuvant-only control mice. Aortic root frozen sections from ApoB3501-3516 immunized mice showed a >60% reduction in aortic sinus plaque development. Aortas from both ApoB3501-3516 and ApoB978-993 immunized mice contained significantly more mRNA for IL-10. Both antigen-specific IgG1 and IgG2c titers were elevated in ApoB3501-3516 or ApoB978-993 immunized mice, suggesting helper T-cell immune activity after immunization.

CONCLUSION

Our data show that MHC Class II restricted ApoB-100 peptides can be atheroprotective, potentially through a mechanism involving elevated IL-10.

The way of self-defence of the organism: inflammation

The acute and chronic constitutional reactions of the organism elicited by sterile causes and pathogenic structures threatening the soundness of the organism are surveyed by the author. It is emphasized that depending on causes which can be very different, there are various syndromes occurring in the clinical practice. On the basis of multitudiness of pathogenic factors and individual differences, the infammatory reactions are clinically, pathologically and pathobiochemically can be hugely variable. The acute inflammatory response may be sterile. It is often difficult to recognize in these processes whether the inflammation is harmful or beneficial for the organism as a whole. It is possible that the inflammatory response itself is the defending resource of the individual. The non-sterile acute inflammation is evoked by pathogenic microorganisms. The variety of clinical syndromes are explained by the high diversity of pathogenic microbes, the individualities of the defending organisms, and the natural and adaptive immunity of the organism which may be intact or possibly defective. In the latter case the inflammation itself is the disease, as a consequence of a pathological process conducted by the cortico-hypothalamo-adernal axis. The acute inflammation is a defending, preventing and repairing process, constituting an important part of the natural innate immune response. It is inseparable from the natural innate immune response, which is in close cooperation with the adaptive, specific immune response with mutual effects on each of the other. The conductor and the response reactions of the two immune responses are also the same. There are alterations in serum proteins/glycoproteins synthesized mostly by the hepatocytes. Because the concentration of almost all proteins/glycoproteins may change, the use of the discriminative term “acute phase reactant” is hardly relevant. For example, the HDL molecule is a negative “acute phase reactant”. On the gound of clinical, pathological and biochemical caracteristics, the chronic sterile inflammation is a very different entity. It has been established that atherosclerosis is one of the ab origine chronic inflammatory syndrome. It is a long-lasting pathological entity progressing, rather than resolving with different celerity, namely a unique vasculitis syndrome. We are speaking about risk factors instead of causes, which constitute larger or smaller groups to elicite the preventing reaction of the host. The propagations and final outcomes are quite different from that of the acute process. The disadvantages or benefits for the organism are scarcely predictable, albeit the chronic process may have roles in its prolonged nature. Orv. Hetil., 2013, 154, 1247–1255.

Chlamydia pneumoniae infection acts as an endothelial stressor with the potential to initiate the earliest heat shock protein 60-dependent inflammatory stage of atherosclerosis

We identified increased expression and redistribution of the intracellular protein 60-kDa human heat shock protein (hHSP60) (HSPD1) to the cell surface in human endothelial cells subjected to classical atherosclerosis risk factors and subsequent immunologic cross-reactivity against this highly conserved molecule, as key events occurring early in the process of atherosclerosis. The present study aimed at investigating the role of infectious pathogens as stress factors for vascular endothelial cells and, as such, contributors to early atherosclerotic lesion formation. Using primary donor-matched arterial and venous human endothelial cells, we show that infection with Chlamydia pneumoniae leads to marked upregulation and surface expression of hHSP60 and adhesion molecules. Moreover, we provide evidence for an increased susceptibility of arterial endothelial cells for redistribution of hHSP60 to the cellular membrane in response to C. pneumoniae infection as compared to autologous venous endothelial cells. We also show that oxidative stress has a central role to play in endothelial cell activation in response to chlamydial infection. These data provide evidence for a role of C. pneumoniae as a potent primary endothelial stressor for arterial endothelial cells leading to enrichment of hHSP60 on the cellular membrane and, as such, a potential initiator of atherosclerosis.

Local and systemic cellular immunity in early renal artery atherosclerosis

BACKGROUND AND OBJECTIVES

Modern imaging techniques have increased the incidental detection of renal atherosclerotic disease (RAD). Because immune activation may hasten RAD progression, identifying cellular immune markers might provide clues to clinical activity. In this study, cellular immune markers were assessed in early RAD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Immune cell markers in peripheral blood of two groups of hypertensive patients with normal carotid and coronary arteries were evaluated: 28 patients had incidental RAD and 22 patients had normal renal arteries; 21 renal arteries obtained at necropsy from individuals with history of hypertension and tissue evidence of RAD were examined and matched with 21 individuals with normal renal arteries. Cell subpopulations were measured by flow cytometry in peripheral blood and direct cell count, respectively, using T and dendritic cells monoclonal antibodies.

RESULTS

Peripheral blood of RAD patients showed increased numbers of cells expressing CD3, CD4, CD83, and CD86. CD4 to CD8 ratio was 8.3 ± 1.4 (RAD) to 3.4 ± 0.9 (normal; P<0.001). No differences were found in CD25, CD8, and S100 among groups. Postmortem samples from RAD showed increased CD3+, CD4+, CD86+, and S100+ cells, whereas CD25+ and CD8+ were unmodified between groups. CD4+ to CD8+ ratio was higher in the RAD(PM) group.

CONCLUSIONS

These results are consistent with an increased expression of immune cell markers in early RAD. Additional studies will explore if they may potentially turn into treatment targets to prevent disease progression.

Identification of mono- or poly-specific monoclonal antibody to Porphyromonas gingivalis heat-shock protein 60

Purpose

The aim of this study was to define the immunoreactive specificity of Porphyromonas gingivalis (P. gingivalis) heat shock protein (HSP) 60 in periodontitis and atherosclerosis.

Methods

In an attempt to define the cross-reactive bacterial heat-shock protein with human self-antigen at molecular level, we have introduced a novel strategy for cloning hybridoma producing anti-P. gingivalis HSP 60 which is polyreactive to bacterial HSPs or to the human homolog.

Results

Five cross-reactive clones were obtained which recognized the #19 peptide (TLVVNRLRGSLKICAVKAPG) among 37 synthetic peptides (20-mer, 5 amino acids overlapping) spanning the whole molecule of P. gingivalis HSP 60. We have also established three anti-P. gingivalis HSP 60 monoclonal antibodies demonstrating mono-specificity. These clones recognized the #29 peptide (TVPGGGTTYIRAIAALEGLK).

Conclusions

Peptide #19 and #29 of P. gingivalis HSP 60 might be important immunoreactive epitopes in the immunopathogenic mechanism of bacterial antigen-triggered autoimmune diseases.

Atypical mycobacteria in a superficial femoral artery occlusion

There is indirect evidence that atherosclerosis may occur in association with bacterial infection. The authors report the case of a young woman who presented with right calf claudication caused by a short occlusion of the superficial femoral artery. Histological examination of the excised segment of artery revealed atheroma and atypical mycobacteria within adventitial caseating granulomata. The possible causes are discussed.

Why should a doctor be interested in oral disease?

Oral health has been implicated in systemic disease throughout the ages; however, the understanding of the relationship between oral disease and systemic diseases such as cardiovascular disease and Type 2 diabetes mellitus is still emerging today. Chronic periodontal disease is widespread in the general population and a significant proportion of adults suffer from the most severe form of the disease. Dental plaque biofilm is necessary for the development of chronic periodontal disease with genetic and environmental factors contributing towards the pathogenesis. The putative biological mechanisms of the association between oral disease and atherogenesis are discussed, although there is insufficient evidence to establish causality at this time. Regardless of a direct causal relationship between oral disease and cardiovascular disease, treatment of oral disease leads to both a reduction in the systemic inflammatory burden as reflected in inflammatory markers and an improvement in endothelial function and hence improved overall health outcomes. A brief overview of periodontal disease including etiology, pathogenesis, screening and therapeutic implications is presented.

Identification of immunoreactive epitopes of the Porphyromonas gingivalis heat shock protein in periodontitis and atherosclerosis

BACKGROUND AND OBJECTIVE

Heat shock protein 60 (HSP60) of Porphyromonas gingivalis, a major periodontal pathogen, might be a trigger molecule linking infectious periodontitis and autoimmune atherosclerosis. The aim of this study was to identify the peptide specificity of anti-P. gingivalis HSP60 monoclonal antibodies and their cross-reactivity with bacterial and human HSPs. Their specific immunoreactivity to periodontal or atherosclerotic lesions was also investigated.

METHODS

Twenty patients with chronic periodontitis and 20 atherosclerosis patients who had undergone surgical intervention for atheromatous plaques with evidence of ongoing periodontal disease, were selected. Synthetic peptide 19 ((TLVVNRLRGSLKICAVKAPG)-specific T-cell lines were established from inflamed gingiva and atheromatous plaque and the phenotypes and cytokine profiles were characterized.

RESULTS

Thirty per cent of periodontitis patients and 100% of atherosclerosis patients reacted positively to cross-reactive peptide 19 from both P. gingivalis and human HSP60. The peptide 19-specific T-cell lines demonstrated the phenotype characteristic of helper T cells (CD4(+)) but did not express CD25 or FOXP3. The interleukin-10 levels were elevated significantly in the peptide 19 T-cell line.

CONCLUSION

Synthetic peptide 19 of P. gingivalis HSP60 is an immunoreactive epitope in the periodontitis-atherosclerosis axis.

General health screening as part of a periodontal examination

Cardiovascular disease (CVD) and type 2 diabetes are common systemic illnesses with reliable, predictive risk factors. CVD is the number one killer worldwide accounting for nearly 30% of deaths and type 2 diabetes has reached epidemic proportions in many western industrialized countries. Both of these illnesses can go undiagnosed in an alarming number of people for significant periods of time. The relationship between oral health and systemic health has become the focus of much discussion and research in recent times. It is now widely accepted that periodontal disease is associated with systemic illnesses such as CVD and type 2 diabetes. Cigarette smoking and obesity are major risk factors accounting for a large portion of the global disease burden. Many periodontal patients may be at risk of systemic conditions but be asymptomatic and undiagnosed. With an aging population who are mostly retaining their natural dentition, the need for periodontal management will continue to rise in the future. Dental professionals are well placed to perform general health screening for their patients. Therefore, risk assessment during the periodontal examination may facilitate the early identification of the large proportion of people who are unaware of their risk status. As identification and intervention of patients with increased risk factors is key to lowering the systemic disease burden, general health screening during periodontal examinations may present an important opportunity for many patients.

Periodontal disease and systemic health: current status

The relationship between poor oral health and systemic diseases has been increasingly recognized over the past two decades. Indeed, the clichés "You cannot have good general health without good oral health", "The mouth is part of the body" and "Floss or die", are gaining an increasing momentum. A large number of epidemiological studies have now linked poor oral health with cardiovascular diseases, poor glycaemic control in diabetics, low birthweight preterm babies and a variety of other conditions. The majority have shown an association, although not always strong. As a result, a number of meta-analyses have been conducted and have confirmed the associations and at the same time cautioned that further studies are required, particularly with regard to the effect of periodontal treatment in reducing risk. A number of biologically plausible mechanisms have been put forward to explain the association and there is accumulating evidence in support of them, although at this stage, insufficient to establish causality. Nevertheless, the relationship between poor oral health and systemic diseases has become a significant issue, such that adult oral health can no longer be ignored in overall health strategies. This review provides an update on current understanding of the contribution of poor oral health to systemic diseases, the possible mechanisms involved and the relevance of this for general dental practitioners.

Chlamydophila pneumoniae infection leads to smooth muscle cell proliferation and thickening in the coronary artery without contributions from a host immune response

Chlamydophila pneumonia (C. pneumonia) infection has been associated with the progression of atherosclerosis. It remains unclear, however, whether C. pneumoniae in the absence of an immune response can alone initiate atherogenic events within a complex vessel environment. Left anterior descending coronary arteries isolated from porcine hearts were dissected and placed in culture medium for 72 hours before infection with C. pneumoniae. C. pneumoniae replicated within the arterial wall for the duration of the experiment (up to 10 days). A significant increase in chlamydial-HSP60 protein expression from day 2 to 10 post-infection (pi) indicated the presence of metabolically active C. pneumonia within infected vessels. Significant arterial thickening in infected coronary segments was observed by a considerable decrease in the ratio of lumen to total vessel area (48 +/- 3% at day 4 pi versus 23 +/- 3% at day 10 pi) and a significant increase in the ratio of media to luminal area (113 +/- 16% at day 4 pi versus 365 +/- 65% at day 10 pi). Structural changes were accompanied by an up-regulation of host HSP60 and proliferating cell nuclear antigen expression levels. Immunohistochemical staining confirmed proliferating cell nuclear antigen expression to be primarily localized within smooth muscle cells of the medial area. These results demonstrate that C. pneumoniae infection can stimulate arterial thickening in a complex vessel environment without the presence of a host immune response and further supports the involvement of HSP60 in this action.

Elevated heat shock protein 60 levels are associated with higher risk of coronary heart disease in Chinese

BACKGROUND

Although heat shock protein 60 (Hsp60) is implicated in the pathogenesis of atherosclerosis, its role in coronary heart disease (CHD) is uncertain. This study explored the influence of circulating Hsp60 on CHD in a large case-control study, as well as the impact of acute myocardial infarction on Hsp60 levels in a prospective study.

METHODS AND RESULTS

Plasma Hsp60 and anti-Hsp60 antibody levels were determined by immunoassay. In the case-control study (1003 patients with CHD, 1003 matched control subjects), Hsp60 levels were higher in patients with CHD and were related to CHD (OR comparing extreme quartiles=4.14, P<0.0001). This association remained after adjustment for traditional risk factors (P for trend <0.0001). Individuals having high levels of Hsp60 (greater than the median of 160.24 ng/mL) and anti-Hsp60 antibody (greater than the median of 38.42 U/mL) were at a greater risk of CHD than those with low levels (OR 2.30, P<0.0001). Stronger additive effects (OR 14.04, P<0.0001) were apparent at higher Hsp60 and anti-Hsp60 antibody levels (>1000 ng/mL and greater than the median of 38.42 U/mL, respectively). The simultaneous presence of high Hsp60 and anti-Hsp60 antibody levels, current smoking, hypertension, and diabetes were cumulatively associated with CHD. Individuals who had any 4 or more of these 5 factors had an OR of 38.61 for CHD (P<0.0001) compared with individuals who had none of these factors. For the prospective study, blood was drawn from 20 patients immediately after admission for acute myocardial infarction and 2, 3, and 7 days thereafter. Hsp60 levels were significantly higher on the day of and the day after arrival than 7 days after an acute myocardial infarction (P=0.011 and P=0.026, respectively).

CONCLUSIONS

Elevated Hsp60 levels are associated with an increased risk for CHD, and Hsp60 and anti-Hsp60 antibody levels combine to increase this risk. In addition, acute myocardial infarction induces Hsp60 release.

T cells in arteritis and atherosclerosis

PURPOSE OF REVIEW

Inflammatory vasculopathies, spanning from atherosclerosis to vasculitides, are driven by innate and adaptive immune responses. Instructed by antigen-presenting cells, T cells have unsurpassed skills to orchestrate protective and pathogenic immunity. Pro-inflammatory and anti-inflammatory T cells regulate master pathogenic pathways, providing a framework for novel immunotherapeutic strategies.

RECENT FINDINGS

The multilayered wall of macrovessels creates a unique tissue niche; professional antigen-presenting cells, specifically dendritic cells, are superior in triggering and maintaining T-cell responses in this tissue milieu. Plaque-residing dendritic cells sense pathogen-derived motifs and edit inflammatory responses. T cells respond to antigen but antigen-nonspecific factors setting cellular response thresholds may be equally important. Dysregulated signal transduction pathways emerge as highly relevant in biasing T cells toward hyperresponsiveness. In the inflamed atheroma and in arteritic lesions, pathogenic T cells coordinate multiple injury pathways. Besides inducing tissue-damaging macrophage functions, they directly inflict cellular injury within the arterial wall. Distinctively, selected T cells induce smooth muscle cell apoptosis, most prominently by upregulating the death-receptor ligand TRAIL.

SUMMARY

Innate sentinels, specifically dendritic cells, populate normal arteries, intramural vasculitic lesions, and the inflamed atheroma. They sense microbial motifs and instruct T cells toward pro-inflammatory and tissue-destructive effector functions. Microenvironmental factors imposed by the unique structure of the arterial wall appear to be highly conserved across disease entities, modulating inflammation in atherosclerosis and arteritis.

Roles of ERK and NF-kappaB in Interleukin-8 Expression in Response to Heat Shock Protein 22 in Vascular Smooth Muscle Cells

Heat shock proteins (HSPs) serve as molecular chaperones and play a role in cell protection from damage in response to stress stimuli. The aim of this article is to investigate whether HSP22 affects IL-8 expression in vascular smooth muscle cells (VSMCs), and which cellular factors are involved in the HSP-mediated IL-8 induction in that cell type in terms of mitogen activated protein kinase (MAPK) and transcription element. Exposure of aortic smooth muscle cells (AoSMCs) to HSP22 not only enhanced IL-8 release but also induced IL-8 transcript via promoter activation. HSP22 activated ERK and p38 MAPK in AoSMCs. HSP22-induced IL-8 release was inhibited by U0126, but not by SB202190. A mutation in the IL-8 promoter region at the binding site of NF-kappaB, but not AP-1 or C/EBP, impaired promoter activation in response to HSP22. Delivery of IkappaB, but not dominant negative c-Jun, lowered HSP22-induced IL-8 release from AoSMCs. These results suggest that HSP22 induces IL-8 in VSMCs via ERK1/2, and that transcription factor NF-kB may be required for the HSP22-induced IL-8 up-regulation.

Administration of M. leprae Hsp65 interferes with the murine lupus progression

The heat shock protein [Hsp] family guides several steps during protein synthesis, are abundant in prokaryotic and eukaryotic cells, and are highly conserved during evolution. The Hsp60 family is involved in assembly and transport of proteins, and is expressed at very high levels during autoimmunity or autoinflammatory phenomena. Here, the pathophysiological role of the wild type [WT] and the point mutated K⁴⁰⁹A recombinant Hsp65 of M. leprae in an animal model of Systemic Lupus Erythematosus [SLE] was evaluated in vivo using the genetically homogeneous [NZBxNZW]F₁ mice. Anti-DNA and anti-Hsp65 antibodies responsiveness was individually measured during the animal's life span, and the mean survival time [MST] was determined. The treatment with WT abbreviates the MST in 46%, when compared to non-treated mice [p<0.001]. An increase in the IgG2a/IgG1 anti-DNA antibodies ratio was also observed in animals injected with the WT Hsp65. Incubation of BALB/c macrophages with F₁ serum from WT treated mice resulted in acute cell necrosis; treatment of these cells with serum from K⁴⁰⁹A treated mice did not cause any toxic effect. Moreover, the involvement of WT correlates with age and is dose-dependent. Our data suggest that Hsp65 may be a central molecule intervening in the progression of the SLE, and that the point mutated K⁴⁰⁹A recombinant immunogenic molecule, that counteracts the deleterious effect of WT, may act mitigating and delaying the development of SLE in treated mice. This study gives new insights into the general biological role of Hsp and the significant impact of environmental factors during the pathogenesis of this autoimmune process.

Genetic variation in heat shock protein 60 gene and coronary heart disease in China: tagging-SNP haplotype analysis in a case-control study

BACKGROUND

High levels of circulating heat shock protein 60 (Hsp60) and antibody to human Hsp60 have been associated with greater risk of coronary heart disease (CHD) in several studies, but associations between polymorphisms of the hsp60 gene and CHD risk have not been investigated.

METHODS

By resequencing DNA from 30 unrelated Han Chinese and using HapMap Phase I Chinese data of hsp60 gene, we selected four tagging single nucleotide polymorphisms (tagSNPs) named rs2340690, rs788016, rs2305560, and rs2565163, and determined their frequencies in 1,003 Chinese CHD patients and 1,003 age- and sex-frequency-matched controls. Furthermore, we used PHASE 2.0 software to reconstruct haplotypes and logistic regression to control for potential confounders in multivariate analyses.

RESULTS

We found 13 SNPs in hsp60 gene (including four novel SNPs) in Han Chinese subjects. Our results showed no significant differences in four selected SNPs in patients with CHD and controls after adjusting for other conventional risk factors and stratifying by age, sex, smoking status, past history of hypertension and DM; however, our results showed that subjects with the GCTC haplotype had about twofold higher risk of CHD than those with the GTTC haplotype (OR = 1.91, 95%CI: 1.26-2.89, P = 0.002).

CONCLUSIONS

Our results suggest that the GCTC haplotype in the hsp60 gene is significantly associated with higher CHD risk in a Chinese population.

Relationship between periodontal infections and systemic disease

Oral conditions such as gingivitis and chronic periodontitis are found worldwide and are among the most prevalent microbial diseases of mankind. The cause of these common inflammatory conditions is the complex microbiota found as dental plaque, a complex microbial biofilm. Despite 3000 years of history demonstrating the influence of oral status on general health, it is only in recent decades that the association between periodontal diseases and systemic conditions such as coronary heart disease and stroke, and a higher risk of preterm low birth-weight babies, has been realised. Similarly, recognition of the threats posed by periodontal diseases to individuals with chronic diseases such as diabetes, respiratory diseases and osteoporosis is relatively recent. Despite these epidemiological associations, the mechanisms for the various relationships remain unknown. Nevertheless, a number of hypotheses have been postulated, including common susceptibility, systemic inflammation with increased circulating cytokines and mediators, direct infection and cross-reactivity or molecular mimicry between bacterial antigens and self-antigens. With respect to the latter, cross-reactive antibodies and T-cells between self heat-shock proteins (HSPs) and Porphyromonas gingivalis GroEL have been demonstrated in the peripheral blood of patients with atherosclerosis as well as in the atherosclerotic plaques themselves. In addition, P. gingivalis infection has been shown to enhance the development and progression of atherosclerosis in apoE-deficient mice. From these data, it is clear that oral infection may represent a significant risk-factor for systemic diseases, and hence the control of oral disease is essential in the prevention and management of these systemic conditions.

Inflammation — a lifelong companion

Inflammation is a key component of the immune system. It has important functions in both defense and pathophysiological events maintaining the dynamic homeostasis of a host organism including its tissues, organs and individual cells. On the cellular level it is controlled by more than 400 currently known genes. Their polymorphisms and environmental conditions give rise to different genotypes in human population. Pro-inflammatory genotype, which dominates in the present population, may be advantageous in childhood but not in elderly people because it is characterized by an increased vulnerability to, and intensity of, inflammatory reactions. These reactions may be the possible reasons of chronic inflammatory diseases, especially in old age. Better understanding of complex molecular and cellular inflammatory mechanisms is indispensable for detailed knowledge of pathogenesis of many diseases, their prevention and directed drug therapy. Here we summarize the basic current knowledge on these mechanisms.

Poliartritis secundaria a instilaciones intravesicales de BCG, a propósito de un caso

Immunotherapy with intravesical instillation of Bacillus Calmette is the best complementary after TUR treatment against T1 grade 2- 3 and CIS bladder cancer. However, this therapy is associated with several side- effects, incluiding joint symptoms. In this article we describe a case of polyarthritis associated with intravesical instillation, a rare complication. We review the clinical features, the pathogenic mechanisms and treatments described previously in the medical literature. Finally, we expose our brief experience and our final result.

Expression of heat shock protein 27 in human atherosclerotic plaques and increased plasma level of heat shock protein 27 in patients with acute coronary syndrome

BACKGROUND

We intended to identify proteins that are differentially expressed in human atherosclerotic plaques.

METHODS AND RESULTS

Comparative 2-dimensional electrophoretic analysis on carotid atherosclerotic endarterectomy specimens (n = 10) revealed that heat shock protein 27 (Hsp27) expression was significantly increased in the nearby normal-appearing area compared with the plaque core area from the same vessel specimen, which was further confirmed by Western blot analysis. The Hsp27 expression in the adjacent normal-appearing vessel areas was much higher than that in nonatherosclerotic reference arteries. The phosphorylation of Hsp27 showed a gradation in the degree of phosphorylation: greatest in the reference arteries, intermediate in the adjacent normal-appearing area, and lowest in plaque core area. Immunohistochemical analysis showed that the phosphorylation of Hsp27 of smooth muscle cells in the carotid endarterectomy specimens was decreased compared with that in the reference artery specimen. The mean plasma level of Hsp27 was significantly higher in patients with acute coronary syndrome (ACS) (n = 27; 106.1 +/- 74.1 ng/mL) than in the normal reference subjects (n = 29; 45.8 +/- 29.5 ng/mL; P < 0.005). The plasma levels of Hsp27 were significantly correlated with those of heat shock protein 70 (Hsp70) (r = 0.422, P < 0.0005), with adjustment for ACS/reference status.

CONCLUSIONS

In the atherosclerotic lesion, Hsp27 expression is increased in the normal-appearing vessel adjacent to atherosclerotic plaque, whereas levels in the plaque itself are significantly decreased. Both plaque and adjacent artery show decreased Hsp27 phosphorylation compared with reference vessel. In ACS, plasma Hsp27 and Hsp70 are increased, and levels of Hsp27 correlate with Hsp70, C-reactive protein, and CD40L levels.

Dysregulation of T-cell function in the elderly : scientific basis and clinical implications

The function of the immune system is to maintain body integrity by defending against infections, cancers, autoimmune diseases and inflammation-related chronic diseases. The immune response is known to become defective with aging, leading to decreased longevity and appearance of age-related disease. The most important changes occur in T-cell immunity, and are manifested particularly as altered clonal expansion of cells of limited antigen specificity. The causes of these alterations are multifactorial, and include thymic involution, T-cell subset changes and signal transduction alterations. The clinical consequences of these changes are not well defined, except for their extremely important negative impact on defence against infections, especially by new pathogens, and decreased responses to vaccination. Considering the public health consequences of decreased immune competence in old age, strategies for immune response modulation are desirable to decrease the health burden for the elderly and improve their quality of life.

Decrease in Circulating Myeloid Dendritic Cell Precursors in Coronary Artery Disease

OBJECTIVES

We analyzed the frequency of myeloid dendritic cell (mDC) and plasmacytoid dendritic cell (pDC) precursors in blood of patients with coronary artery disease (CAD) and in atherosclerotic carotid plaques of patients with cerebrovascular disease (CVD).

BACKGROUND

Circulating DC precursors are reduced in several autoimmune diseases. Atherosclerosis has features of an autoimmune disease, such as the presence of autoantibodies or autoreactive T cells. Tissue-resident DCs were previously described in atheromata, and it is assumed that they are important for the activation of T cells against autoantigens there.

METHODS

Circulating mDC and pDC precursors were flow cytometrically detected in healthy controls (n = 19), CAD patients with stable (n = 20) and unstable angina pectoris (n = 19), and acute myocardial infarction (n = 17). In human carotid plaques (n = 65), mDC and pDC precursors were identified immunohistochemically.

RESULTS

Circulating mDC precursors were significantly reduced in patients with stable angina pectoris (0.19%, p = 0.04), unstable angina pectoris (0.16%, p = 0.004), and acute myocardial infarction (0.08%, p < 0.001) compared with control patients (0.22% of peripheral blood mononuclear cells). In contrast, pDC numbers were not significantly altered. Circulating mDC precursors inversely correlated with high-sensitivity C-reactive protein (r = -0.38, p = 0.001) or interleukin-6 (r = -0.42, p < 0.001). In contrast to pDC, significantly more mDC precursors were observed in vulnerable carotid plaques (24, 0.25 mm2; n = 31; p = 0.003) than in stable ones (6.4, 0.25 mm2; n = 34).

CONCLUSIONS

Similar to autoimmune diseases, circulating mDC precursors were significantly reduced in patients with CAD. The emergence of mDC precursors in vulnerable plaques suggests their recruitment into atheromata as a possible reason for their decrease in blood. In contrast, no significant association of circulating pDC precursors with atherosclerosis was observed.

Anti-HSP60 immunity is already associated with atherosclerosis early in life

In this review, we first briefly introduce the reader to our autoimmune hypothesis for the development of atherosclerosis based on experimental and clinical data. This hypothesis postulates that humoral and cellular immunity against heat-shock protein 60 (HSP60), a phylogenetically highly conserved stress protein, is the mechanism that initiates atherogenesis. We then turn to our investigations of arterial specimens from children and young adults. These clearly show that mononuclear cell infiltrations of the intimal layer already occur before the emergence of clear-cut atherosclerotic lesions, a phenomenon we have termed vascular-associated lymphoid tissue (VALT). In early lesions analyzed within the framework of the Pathological Determinants of Atherosclerosis in Youth (PDAY) study, T lymphocytes proved to be a major cellular constituent. In the Bruneck Study, a large, prospective atherosclerosis-prevention study in adults aged 40 years and older, we found a highly significant correlation between serum anti-HSP60 antibody titers and the occurrence and extent of sonographically demonstrable atherosclerotic lesions. However, no such correlation emerged with respect to HSP60-reactive T cells in the peripheral blood. In contrast, the similar Atherosclerosis Risk-Factors in Male Youngsters (ARMY) study, performed on 17- to 18-year-old volunteers, showed a highly statistically significant correlation between arterial intima-media thickening and HSP60 reactivity among peripheral T cells and (less pronounced) anti-HSP60 antibodies, even at this young age. We take this as indirect evidence that both T cell and B cell immunity against HSP60 plays a major role in the earliest stages of the disease. Because VALT can already be observed in healthy children and young adults, we hypothesize that T cells initiate the disease and that humoral antibodies play a facilitating, accelerating role. Finally, we provide initial evidence that smoking, as the most important risk factor for atherogenesis, also exerts its disease-inducing and disease-promoting effects by inducing HSP60 expression by vascular endothelial cells.