T cells in arteritis and atherosclerosis

Immune landscape and regulatory mechanisms in human atherosclerotic coronary plaques: Evidence from single-cell and bulk transcriptomics

Atherosclerosis is a chronic immuno-inflammatory disease, however, the immune landscape and regulatory mechanisms have not been clear. We detected seven principal immune cell clusters with distinct phenotypic and spatial characteristics using single-cell RNA-sequencing of aortic immune cells from patients with acute coronary syndrome and stable angina pectoris. Then we acquired 265 differentially expressed immune-related genes and the high scores were mainly found in T cells and monocytes, which were differentially regulated in atherosclerotic coronary plaques. The CCL signaling pathway was the most relevant pattern in the T cells and CCL5-CCR1 and CCL5-CCR5 ligand-receptor pairs played a vital role in the CCL signaling pathway. Further comparative analysis indicated MCH-I signaling was the most relevant pattern in the T cells and HLA ligand-related ligand-receptor pairs played a vital role. Functional analysis of the single-cell and bulk transcriptomics pointed to multiple pathways, such as antigen presentation and immune response. Nineteen common differentially expressed immune-related genes were found in both immune cells and the human peripheral blood mononuclear cells. Nine common differentially expressed transcription factors were differentially expressed in both T cell and monocyte clusters from the coronary plaques and human peripheral blood mononuclear cells and the network demonstrated that CEBPB might play an essential role in the transcriptional regulation of atherosclerosis as a hub transcription factor. The definition of immune cell diversity and heterogeneity by single-cell level analysis of aortic immune cell subsets not only unveils cell-type-specific pathways and new immune mechanisms but also discovers the functional correlation of immune cells in human atherosclerosis. Our findings provide great promise for the discovery of novel molecular mechanisms and precise therapeutic targets for atherosclerosis.

Combined Single-Cell RNA and Single-Cell α/β T Cell Receptor Sequencing of the Arterial Wall in Atherosclerosis

Although various pro- and anti-inflammatory T cell subsets have been observed in murine and human atherosclerosis, principal issues of T cell immunity remain unanswered: Is atherosclerosis progression critically affected by aberrant T cell responses? Are tolerance checkpoints compromised during atherosclerosis progression? Answers to these questions will determine if we are at the cusp of developing T cell-dependent therapeutic strategies. Rapid advances in single cell RNA sequencing (scRNA-seq) and single cell α/β T cell receptor (TCR) (scTCR) sequencing allows to address these issues in unprecedented ways. The majority of T cells recognize peptide antigen-MHC complexes presented by antigen-presenting cells which, in turn, trigger activation and proliferation (clonal expansion) of cognate TCR-carrying T cells. Thus, clonal expansion and their corresponding transcriptome are two similarly important sides of T cell immunity and both will-as hypothesized-affect the outcome of atherosclerosis. Here, we combined scRNA-seq and scTCR-seq in single cells. Moreover, we provide single T cell transcriptomes and TCR maps of three important tissues involved in atherosclerosis This approach is anticipated to address principal questions concerning atherosclerosis autoimmunity that are likely to pave the long sought way to T cell-dependent therapeutic approaches.

PD-1/PD-L1 immune checkpoints: Tumor vs atherosclerotic progression

Immunotherapy has become one of the most attraction cancer therapy strategies. The PD-1/PD-L1 pathway plays key roles in immune responses and autoimmunity by regulating T cell activity. Overactivation of this pathway dampens T cell and immune function, which allows tumor cells immune escape. Antibody or inhibitors of PD-1/PD-L1 immune targets have been implicated in clinic anti-cancer therapy and gain great clinic outcoming for their high efficiency. However, recent studies showed that the PD-1/PD-L1 immunotherapy in some tumor patients was found to accelerate T cell-driven inflammatory and the progression of atherosclerotic lesions. This article reviews the research progression of PD-1/PD-L1 in tumors and atherosclerosis, and the possible mechanisms of anti-PD-1/PD-L1 immunotherapy increasing the risk of atherosclerotic lesions.

Inflammatory Activities in Type 2 Diabetes Patients With Co-morbid Angiopathies and Exploring Beneficial Interventions: A Systematic Review

Background: Diabetes is a long-term condition that can be treated and controlled but do not yet have a cure; it could be induced by inflammation and the goal of managing it is to prevent additional co-morbidities and reduce glycemic fluctuations. There is a need to examine inflammatory activities in diabetes-related angiopathies and explore interventions that could reduce the risk for future outcome or ameliorate its effects to provide insights for improved care and management strategies.

Method: The study was conducted in Embase (1946–2020), Ovid Medline (1950–2020), and PubMed databases (1960–2020) using the PICO framework. Primary studies (randomized controlled trials) on type 2 diabetes mellitus and inflammatory activities in diabetes-related angiopathies were included. Terms for the review were retrieved from the Cochrane library and from PROSPERO using its MeSH thesaurus qualifiers. Nine articles out of 454 total hits met the eligibility criteria. The quality assessment for the selected study was done using the Center for Evidence-Based Medicine Critical Appraisal Sheet.

Results: Data analysis showed that elevated CRP, TNF-α, and IL-6 were the most commonly found inflammatory indicator in diabetes-related angiopathies, while increased IL-10 and soluble RAGE was an indicator for better outcome. Use of drugs such as salsalate, pioglitazone, simvastatin, and fenofibrate but not glimepiride or benfotiamine reported a significant decrease in inflammatory events. Regular exercise and consumption of dietary supplements such as ginger, hesperidin which have anti-inflammatory properties, and those containing prebiotic fibers (e.g., raspberries) revealed a consistent significant (p < 0.05) reduction in inflammatory activities.

Conclusion: Inflammatory activities are implicated in diabetes-related angiopathies; regular exercise, the intake of healthy dietary supplements, and medications with anti-inflammatory properties could result in improved protective risk outcome for diabetes patients by suppressing inflammatory activities and elevating anti-inflammatory events.

Clinical and pathological evolution of giant cell arteritis: a prospective study of follow-up temporal artery biopsies in 40 treated patients

Although clinical signs and symptoms of giant cell arteritis improve promptly after starting glucocorticoid therapy, reports have suggested that the vascular inflammation may persist. To assess the duration and quality of histopathologic changes in treated patients, we prospectively obtained second temporal artery biopsies in patients treated for 3 to 12 months after their first diagnostic biopsy. Forty patients (28 women, 12 men, median age 77 years) agreed to have a second temporal artery biopsy randomly assigned to 3, 6, 9, or 12 months subsequent to the first. Clinical and laboratory evaluation of the patient cohort revealed a typical rapid response and continued suppression of clinical manifestations as a result of glucocorticoid treatment. Histopathologic findings, evaluated in a blinded manner by a cardiovascular pathologist, showed unequivocal findings of vasculitis in 7/10 patients with second temporal artery biopsy at 3 months, 9/12 at 6 months, 4/9 at 9 months, and 4/9 at 12 months. Lymphocytes were present in all positive initial biopsies and remained the dominant cell population in chronically treated patients. Granulomatous inflammation decreased in a time-dependent manner from 78 to 100% at initial biopsy to 50% at 9 months and 25% at 12 months. The increased medial fibrosis noted in the second biopsies (60 vs 33% in primary temporal artery biopsies) suggested that the finding may represent a chronic finding in arteritis. In summary, the response to glucocorticoids in giant cell arteritis was frequently discordant. Clinical manifestations were readily suppressed, but vascular changes were gradual and often incomplete.

Dysfunction of the ubiquitin-proteasome system in atherosclerotic cardiovascular disease

The ubiquitin-proteasome system (UPS) is an integral part of the protein metabolism and protein quality control in eukaryotic cells. It is involved in a number of biological processes of significance for vascular biology and pathology such as oxidative stress, inflammation, foam cell formation, and apoptosis. This review summarizes both indirect and direct lines of evidence for a role of the UPS in atherosclerosis from the initiation to the progression and complication stage and concludes with a future perspective.

Serpin treatment suppresses inflammatory vascular lesions in temporal artery implants (TAI) from patients with giant cell arteritis

Giant cell arteritis (GCA) and Takayasu’s disease are inflammatory vasculitic syndromes (IVS) causing sudden blindness and widespread arterial obstruction and aneurysm formation. Glucocorticoids and aspirin are mainstays of treatment, predominantly targeting T cells. Serp-1, a Myxomavirus-derived serpin, blocks macrophage and T cells in a wide range of animal models. Serp-1 also reduced markers of myocardial injury in a Phase IIa clinical trial for unstable coronary disease. In recent work, we detected improved survival and decreased arterial inflammation in a mouse Herpesvirus model of IVS. Here we examine Serp-1 treatment of human temporal artery (TA) biopsies from patients with suspected TA GCA arteritis after implant (TAI) into the aorta of immunodeficient SCID (severe combined immunodeficiency) mice. TAI positive for arteritis (GCA^pos) had significantly increased inflammation and plaque when compared to negative TAI (GCA^neg). Serp-1 significantly reduced intimal inflammation and CD11b⁺ cell infiltrates in TAI, with reduced splenocyte Th1, Th17, and Treg. Splenocytes from mice with GCA^pos grafts had increased gene expression for interleukin-1beta (IL-1β), IL-17, and CD25 and decreased Factor II. Serp-1 decreased IL-1β expression. In conclusion, GCA^pos TAI xenografts in mice provide a viable disease model and have increased intimal inflammation as expected and Serp-1 significantly reduces vascular inflammatory lesions with reduced IL-1β.

Stimulatory interactions between human coronary smooth muscle cells and dendritic cells

Despite inflammatory and immune mechanisms participating to atherogenesis and dendritic cells (DCs) driving immune and non-immune tissue injury response, the interactions between DCs and vascular smooth muscle cells (VSMCs) possibly relevant to vascular pathology including atherogenesis are still unclear. To address this issue, immature DCs (iDCs) generated from CD14+ cells isolated from healthy donors were matured either with cytokines (mDCs), or co-cultured (ccDCs) with human coronary artery VSMCs (CASMCs) using transwell chambers. Co-culture induced DC immunophenotypical and functional maturation similar to cytokines, as demonstrated by flow cytometry and mixed lymphocyte reaction. In turn, factors from mDCs and ccDCs induced CASMC migration. MCP-1 and TNFα, secreted from DCs, and IL-6 and MCP-1, secreted from CASMCs, were primarily involved. mDCs adhesion to CASMCs was enhanced by CASMC pre-treatment with IFNγ and TNFα ICAM-1 and VCAM-1 were involved, since the expression of specific mRNAs for these molecules increased and adhesion was inhibited by neutralizing antibodies to the counter-receptors CD11c and CD18. Adhesion was also inhibited by CASMC pre-treatment with the HMG-CoA-reductase inhibitor atorvastatin and the PPARγ agonist rosiglitazone, which suggests a further mechanism for the anti-inflammatory action of these drugs. Adhesion of DCs to VSMCs was shown also in vivo in rat carotid 7 to 21 days after crush and incision injury. The findings indicate that DCs and VSMCs can interact with reciprocal stimulation, possibly leading to perpetuate inflammation and vascular wall remodelling, and that the interaction is enhanced by a cytokine-rich inflammatory environment and down-regulated by HMGCoA-reductase inhibitors and PPARγ agonists.

Lymphocyte-suppressing action of simvastatin in patients with isolated hypertriglyceridemia

BACKGROUND

No previous study examined whether statins affect lymphocyte cytokine release in patients with isolated hypertriglyceridemia.

METHODS

The study included 46 patients with elevated triglyceride levels and peripheral artery stenosis, randomly assigned to receive simvastatin or placebo. Plasma lipids, glucose homeostasis markers, plasma C-reactive protein and lymphocyte cytokine release were measured at baseline and at the end of the treatment.

RESULTS

Ninety-day simvastatin treatment reduced lymphocyte release of TNF-α, interleukin-2 and interferon-γ, which was accompanied by a decrease in plasma C-reactive protein.

CONCLUSION

The obtained results suggest that statins produce lymphocyte-suppressing and systemic anti-inflammatory effects in patients with isolated hypertriglyceridemia.

What is causing my arthritis, doctor? A glimpse beyond the usual suspects in the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA) is a common, but heterogeneous, disease. Usually, when it comes to the pathogenesis of RA the physician faces a complex network of cytokines and cells of the immune system-the so-called effector level. However, is this network 'the cause' of the disease? Or is this rather the level most physicians are somewhat familiar with, as modern anti-rheumatic medications are having their targets there? In this review, we are looking beyond the usual culprits from the physician's perspective and discuss how other factors, such as genes, epigenetics, environmental factors, local joint characteristics or processes of aging might influence the clinical phenomenon RA.

CTLA4-IgG ameliorates homocysteine-accelerated atherosclerosis by inhibiting T-cell overactivation in apoE(-/-) mice

AIMS

Cytotoxic T lymphocyte antigen 4 (CTLA4) exerts inhibitory effects on T-cell activation by competition with CD28. In this study, we investigated the effect of CTLA4-IgG on homocysteine (Hcy)-induced T-cell activation and potential signal pathways involved in atherosclerotic formation.

METHODS AND RESULTS

The CD28 signal was significantly amplified by Hcy treatment in splenic T cells and hyperhomocysteinaemia (HHcy)-accelerated plaques in apolipoprotein E-deficient (apoE(-/-)) mice. As a major competitor of CD28, CTLA4-IgG (abatacept) pretreatment, 100 μg/week, in apoE(-/-) mice could reverse 2- and 4-week HHcy-accelerated atherosclerosis. Furthermore, the membrane level of CTLA4 was decreased and the endocytosis level was increased by HHcy. Endocytosed CTLA4 molecules by Hcy were in large vesicles, colocalized with lysosomes and endosomes. Hcy-increased CTLA4 endocytosis and secretion of inflammatory cytokines in T cells were blocked by CTLA4-IgG and the PI3K inhibitor LY294002. Blocking the CD28 signal pathway in T cells significantly decreased Hcy-promoted macrophage migration.

CONCLUSION

These results illustrate a novel mechanism of CD28-dependent T-cell costimulation involved in HHcy-accelerated atherosclerosis, which extends the pharmacological application of CTLA4-IgG for atherosclerosis.

The immunopathology of giant cell arteritis: diagnostic and therapeutic implications

Giant cell arteritis (GCA) is an important cause of preventable blindness, most commonly due to anterior ischemic optic neuropathy. Ischemic tissue injury is the end result of a process that begins within the walls of susceptible arteries in which local dendritic cells (DCs) recruit and activate CD4 T cells that, in turn, direct the activity of effector macrophages. In response to the immune attack, the blood vessel forms lumen-stenosing intima. Multiple cascades of excessive T-cell reactivity contribute to the autoimmune features of giant cell arteritis with TH1 and TH17 immunity responsible for the early phase and TH1 immunity promoting chronic-smoldering inflammation. These cascades are only partially overlapping, supporting the concept that a multitude of instigators induce and sustain vascular inflammation. The artery actively participates in the abnormal immune response through endogenous immune sentinels, so-called vascular DCs embedded in the adventitia. Advancing age, the strongest of all risk factors for GCA, contributes to both, the dysfunction of the immune system and the vascular system. Expansion of the therapeutic armamentarium for GCA needs to focus on approaches that mitigate the impact of the aging artery and adapt to the needs of the immunosenescent host.

The effect of ezetimibe, administered alone or in combination with simvastatin, on lymphocyte cytokine release in patients with elevated cholesterol levels

OBJECTIVE

Studies assessing the extra-lipid effects of ezetimibe have provided contrasting results. In the present study, we compared the effects of ezetimibe and simvastatin, administered alone or in combination, on the secretory function of human lymphocytes, systemic inflammation and endothelial function in subjects with elevated cholesterol levels.

METHODS

A prospective study involving a group of 178 ambulatory patients with isolated hypercholesterolaemia who were randomly assigned in a double-blind fashion to 90days of treatment with ezetimibe (10mg), simvastatin (40mg), ezetimibe (10mg) plus simvastatin (4mg) or placebo. A total of 170 patients completed the study.

MAIN OUTCOME MEASURES

Lymphocyte cytokine release and plasma levels of high-sensitivity C-reactive protein (hsCRP) and intercellular adhesion molecule 1 (ICAM-1).

RESULTS

Although both drugs reduced lymphocyte release of tumour necrosis factor-α, interferon-γ and interleukin-2 in a lipid-independent manner, only the effect of simvastatin was statistically significant (P<0.001). This lymphocyte-suppressing effect, which was accompanied by a decrease in plasma levels of hsCRP and ICAM-1 (P<0.001), was strongest in patients receiving both simvastatin and ezetimibe. There were no differences in lymphocyte-suppressing, systemic anti-inflammatory and endothelial protective effects of simvastatin between insulin-resistant and insulin-sensitive subjects, whereas the effects of ezetimibe and the combined treatment were greater in the former group of patients (P<0.01 and P<0.001, respectively).

CONCLUSIONS

The results of this study indicate that simvastatin is superior to ezetimibe in producing lymphocyte-suppressing, systemic anti-inflammatory and endothelial protective effects in patients with elevated cholesterol levels. Hypercholesterolaemic patients with high cardiovascular risk may receive the greatest benefits from concomitant treatment with a statin and ezetimibe.

The ubiquitin-proteasome system and cardiovascular disease

Over the past decade, the role of the ubiquitin-proteasome system (UPS) has been the subject of numerous studies to elucidate its role in cardiovascular physiology and pathophysiology. There have been many advances in this field including the use of proteomics to achieve a better understanding of how the cardiac proteasome is regulated. Moreover, improved methods for the assessment of UPS function and the development of genetic models to study the role of the UPS have led to the realization that often the function of this system deviates from the norm in many cardiovascular pathologies. Hence, dysfunction has been described in atherosclerosis, familial cardiac proteinopathies, idiopathic dilated cardiomyopathies, and myocardial ischemia. This has led to numerous studies of the ubiquitin protein (E3) ligases and their roles in cardiac physiology and pathophysiology. This has also led to the controversial proposition of treating atherosclerosis, cardiac hypertrophy, and myocardial ischemia with proteasome inhibitors. Furthering our knowledge of this system may help in the development of new UPS-based therapeutic modalities for mitigation of cardiovascular disease.

Giant cell arteritis: immune and vascular aging as disease risk factors

Susceptibility for giant cell arteritis increases with chronological age, in parallel with age-related restructuring of the immune system and age-induced remodeling of the vascular wall. Immunosenescence results in shrinkage of the naïve T-cell pool, contraction of T-cell diversity, and impairment of innate immunity. Aging of immunocompetent cells forces the host to take alternative routes for protective immunity and confers risk for pathogenic immunity that causes chronic inflammatory tissue damage. Dwindling immunocompetence is particularly relevant as the aging host is forced to cope with an ever growing infectious load. Immunosenescence coincides with vascular aging during which the arterial wall undergoes dramatic structural changes and medium and large arteries lose their pliability and elasticity. On the molecular level, elastic fibers deteriorate and matrix proteins accumulate biochemical modifications. Thus, the aging process impacts the two major biologic systems that liaise to promote giant cell arteritis; the immune system and the vessel wall niche.

Polymyalgia rheumatica and giant cell arteritis: management of two diseases of the elderly

Both polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) present with a broad spectrum of clinical manifestations and almost exclusively occur in the population aged over 50 years. After rheumatoid arthritis, PMR is the second most common autoimmune rheumatic disorder. Visual loss is the most feared complication in temporal arteritis, and extracranial arteries and/or aorta are more often involved in GCA than previously estimated. No specific laboratory parameter exists for diagnosis of PMR. Imaging techniques such as ultrasonography, MRI or 18F-fluorodeoxyglucose PET may be helpful in the diagnosis and evaluation of the extent of vascular involvement in these diseases. This article highlights upcoming new classification criteria for PMR, recent advances of diagnostic and therapeutic procedures as well as ongoing research on biomarkers and corticosteroid-sparing medications, which should improve management of PMR and GCA.

Peroxisome proliferator-activated receptor-γ agonists prevent in vivo remodeling of human artery induced by alloreactive T cells

BACKGROUND

Ligands activating the transcription factor peroxisome proliferator-activated receptor-γ (PPARγ) have antiinflammatory effects. Vascular rejection induced by allogeneic T cells can be responsible for acute and chronic graft loss. Studies in rodents suggest that PPARγ agonists may inhibit graft vascular rejection, but human T-cell responses to allogeneic vascular cells differ from those in rodents, and the effects of PPARγ in human transplantation are unknown.

METHODS AND RESULTS

We tested the effects of PPARγ agonists on human vascular graft rejection using a model in which human artery is interposed into the abdominal aorta of immunodeficient mice, followed by adoptive transfer of allogeneic (to the artery donor) human peripheral blood mononuclear cells. Interferon-γ-dependent rejection ensues within 4 weeks, characterized by intimal thickening, T-cell infiltrates, and vascular cell activation, a response resembling clinical intimal arteritis. The PPARγ agonists 15-deoxy-prostaglandin-J(2), ciglitazone, and pioglitazone reduced intimal expansion, intimal infiltration of CD45RO(+) memory T cells, and plasma levels of inflammatory cytokines. The PPARγ antagonist GW9662 reversed the protective effects of PPARγ agonists, confirming the involvement of PPARγ-mediated pathways. In vitro, pioglitazone inhibited both alloantigen-induced proliferation and superantigen-induced transendothelial migration of memory T cells, indicating the potential mechanisms of PPARγ effects.

CONCLUSION

Our results suggest that PPARγ agonists inhibit allogeneic human memory T cell responses and may be useful for the treatment of vascular graft rejection.

The effect of bezafibrate and omega-3 fatty acids on lymphocyte cytokine release and systemic inflammation in patients with isolated hypertriglyceridemia

PURPOSE

The aim of this study was to compare the effects of fibrates and omega-3 fatty acids on lymphocyte secretory function and systemic inflammation in patients with isolated hypertriglyceridemia.

METHODS

The study included 107 patients with isolated hypertriglyceridemia who received bezafibrate (200 mg twice daily), omega-3 fatty acids (1 g twice daily) or placebo for 12 weeks. The lipid profile, fasting and 2-h post-glucose load plasma glucose levels, homeostasis model assessment index (HOMA), plasma high-sensitivity C-reactive protein (hsCRP) levels and lymphocyte release of interleukin-2, interferon-γ and tumor necrosis factor-α were assessed at baseline, on the day of randomization, and after 4 and 12 weeks of treatment.

RESULTS

Both bezafibrate and omega-3 fatty acids reduced plasma triglyceride levels. Bezafibrate additionally decreased total and low-density lipoprotein-cholesterol levels and the HOMA and insignificantly decreased post-glucose load plasma glucose, as well as increased high-density lipoprotein-cholesterol. Bezafibrate treatment was associated with a reduction in lymphocyte release of interleukin-2, interferon-γ and tumor necrosis factor-α, which was accompanied by a reduction in plasma hsCRP levels. Omega-3 fatty acid did not significantly reduce lymphocyte cytokine release and plasma hsCRP. The anti-inflammatory effects of both drugs did not correlate with their action on plasma lipids, but in the case of the former the effect was related to the improvement in insulin sensitivity.

CONCLUSION

Our results indicate that bezafibrate is superior to omega-3 fatty acid in inhibiting systemic inflammation and lymphocyte secretory function.

Effect of simvastatin and fenofibrate on cytokine release and systemic inflammation in type 2 diabetes mellitus with mixed dyslipidemia

The aim of our study was to compare the effect of simvastatin and fenofibrate treatment on the secretory function of human monocytes and lymphocytes and on systemic inflammation in type 2 diabetes and to assess whether their coadministration is superior to treatment with only 1 of these drugs. One hundred ninety-six adult patients with recently diagnosed and previously untreated type 2 diabetes and mixed dyslipidemia, complying throughout the study with lifestyle intervention and treated with metformin, were randomized in a double-blind fashion to receive simvastatin (40 mg), fenofibrate (200 mg), simvastatin plus fenofibrate, or placebo for 90 days. Main outcome measurements were monocyte and lymphocyte release of proinflammatory cytokines and plasma levels of C-reactive protein. One hundred ninety patients completed the study. Simvastatin and fenofibrate decreased monocyte release of tumor necrosis factor-α, interleukin-1β, interleukin-6, and monocyte chemoattractant protein-1 and lymphocyte release of interleukin-2, interferon-γ, and tumor necrosis factor-α, which was accompanied by a decrease in plasma C-reactive protein levels. Anti-inflammatory effects of fenofibrate partly correlated with the improvement in insulin sensitivity. Lymphocyte-suppressing, but not monocyte-suppressing, effect was stronger if these 2 agents were administered together. In conclusion, simvastatin and fenofibrate exhibit a similar effect on the secretory function of human monocytes and lymphocytes and on systemic inflammation in type 2 diabetic subjects with mixed dyslipidemia. This effect may be clinically relevant in the prevention of vascular complications in metformin- and diet-treated subjects with newly diagnosed diabetic dyslipidemia.

Immune aging and rheumatoid arthritis

Immunologic models of rheumatoid arthritis (RA) have to take into account that the disease occurs at an age when immunocompetence is declining and in a host whose immune system shows evidence of accelerated immune aging. By several immune aging biomarkers, the immune system in patients with RA is prematurely aged by more than 20 years. One major pathogenetic mechanism is a defect in telomere maintenance and DNA repair that causes accelerated cell death. These findings in RA are reminiscent of murine autoimmunity models, in which lymphopenia was identified as a major risk factor for autoimmunity. Progress in the understanding of how accelerated immune aging is pathogenetically involved in RA may allow development of new therapeutic approaches that go beyond the use of anti-inflammatory agents and eventually could open new avenues for preventive intervention.

The effect of fenofibrate on lymphocyte cytokine release in patients with impaired fasting glucose and impaired glucose tolerance: a preliminary report

OBJECTIVE

The aim of our study was to investigate the effect of fenofibrate on lymphocyte secretory function in patients with isolated early glucose metabolism abnormalities.

METHODS

Fifty-eight patients with impaired fasting glucose (IFG), fifty-six subjects with impaired glucose tolerance (IGT) and fifty-five normolipidemic control subjects with asymptomatic atherosclerosis, were treated for 90 days with either micronized fenofibrate (200 mg/day) or placebo.

RESULTS

Compared to control subjects, lymphocytes of both IGF and IGT patients released more amounts of interleukin-2, interferon-γ and TNF-α, and exhibited higher plasma levels of hsCRP. Despite improving glucose metabolism markers in both IFG and IGT subjects, fenofibrate reduced lymphocyte cytokine release only in the latter group of patients.

CONCLUSIONS

Our results show for the first time that lymphocyte secretory function is disturbed at early stages of glucose metabolism disturbances and that IGT- but not IFG-induced abnormal function of T cells is corrected by fenofibrate administration.

Telmisartan: a different angiotensin II receptor blocker protecting a different population?

The ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET()) showed that the angiotensin II receptor blocker (ARB) telmisartan was as protective as the reference-standard ramipril in a broad cross-section of patients at increased cardiovascular risk, but was better tolerated. Telmisartan has a unique profile among ARBs, with a high affinity for the angiotensin II type 1 receptor, a long duration of receptor binding, a high lipophilicity and a long plasma half life. This leads to sustained and powerful blood pressure lowering when compared with the first marketed ARBs, such as losartan and valsartan. Some pharmacological properties of telmisartan clearly distinguish it from other members of the ARB class and may contribute to the clinical effects seen with telmisartan. A class effect for ARBs cannot be assumed. To date, telmisartan is the only ARB that has been shown to reduce cardiovascular risk in at-risk cardiovascular patients.

Th17 and Th1 T-cell responses in giant cell arteritis

BACKGROUND

In giant cell arteritis (GCA), vasculitic damage of the aorta and its branches is combined with a syndrome of intense systemic inflammation. Therapeutically, glucocorticoids remain the gold standard because they promptly and effectively suppress acute manifestations; however, they fail to eradicate vessel wall infiltrates. The effects of glucocorticoids on the systemic and vascular components of GCA are not understood.

METHODS AND RESULTS

The immunoprofile of untreated and glucocorticoid-treated GCA was examined in peripheral blood and temporal artery biopsies with protein quantification assays, flow cytometry, quantitative real-time polymerase chain reaction, and immunohistochemistry. Plasma interferon-gamma and interleukin (IL)-17 and frequencies of interferon-gamma-producing and IL-17-producing T cells were markedly elevated before therapy. Glucocorticoid treatment suppressed the Th17 but not the Th1 arm in the blood and the vascular lesions. Analysis of monocytes/macrophages in the circulation and in temporal arteries revealed glucocorticoid-mediated suppression of Th17-promoting cytokines (IL-1beta, IL-6, and IL-23) but sparing of Th1-promoting cytokines (IL-12). In human artery-severe combined immunodeficiency mouse chimeras, in which patient-derived T cells cause inflammation of engrafted human temporal arteries, glucocorticoids were similarly selective in inhibiting Th17 cells and leaving Th1 cells unaffected.

CONCLUSIONS

Two pathogenic pathways mediated by Th17 and Th1 cells contribute to the systemic and vascular manifestations of GCA. IL-17-producing Th17 cells are sensitive to glucocorticoid-mediated suppression, but interferon-gamma-producing Th1 responses persist in treated patients. Targeting steroid-resistant Th1 responses will be necessary to resolve chronic smoldering vasculitis. Monitoring Th17 and Th1 frequencies can aid in assessing disease activity in GCA.

Inflammation in atherosclerosis: from pathophysiology to practice

Until recently, most envisaged atherosclerosis as a bland arterial collection of cholesterol, complicated by smooth muscle cell accumulation. According to that concept, endothelial denuding injury led to platelet aggregation and release of platelet factors which would trigger the proliferation of smooth muscle cells in the arterial intima. These cells would then elaborate an extracellular matrix that would entrap lipoproteins, forming the nidus of the atherosclerotic plaque. Beyond the vascular smooth muscle cells long recognized in atherosclerotic lesions, subsequent investigations identified immune cells and mediators at work in atheromata, implicating inflammation in this disease. Multiple independent pathways of evidence now pinpoint inflammation as a key regulatory process that links multiple risk factors for atherosclerosis and its complications with altered arterial biology. Knowledge has burgeoned regarding the operation of both innate and adaptive arms of immunity in atherogenesis, their interplay, and the balance of stimulatory and inhibitory pathways that regulate their participation in atheroma formation and complication. This revolution in our thinking about the pathophysiology of atherosclerosis has now begun to provide clinical insight and practical tools that may aid patient management. This review provides an update of the role of inflammation in atherogenesis and highlights how translation of these advances in basic science promises to change clinical practice.

Vascular damage in giant cell arteritis

Immune-mediated damage to medium-sized arteries results in wall remodeling with intimal hyperplasia, luminal stenosis and tissue ischemia. In the case of the aorta, vasculitis may result in dissection, aneurysm or rupture. The response-to-injury program of the blood vessel is a concerted action between the immune system and wall-resident cells, involving the release of growth and angiogenic factors from macrophages and giant cells and the migration and hyperproliferation of vascular smooth muscle cells. Innate immune cells, specifically, dendritic cells (DC) positioned in the vessel wall, have been implicated in the earliest steps of vasculitis. Pathogen-derived molecular patterns are capable of activating vascular DC and initiating adaptive immune responses. The pattern of the emerging vessel wall inflammation is ultimately determined by the initial insult. Ligands to toll-like receptor (TLR) 4, such as lipopolysaccharides, facilitate the recruitment of CD4 T cells that invade deep into the wall and distribute in a panarteritic pattern. Conversely, ligands for TLR5 condition vascular DC to support perivasculitic infiltrates. In essence, both innate and adaptive immune reactions collaborate to render the arterial wall susceptible to inflammatory damage. Unique features of the tissue microenvironment, including specialized DC, shape the course of the inflammatory response. Differences in vascular damage pattern encountered in different patients may relate to distinct instigators of vasculitis.

On to the road to degradation: atherosclerosis and the proteasome

Protein metabolism is a central element of every living cell. The ubiquitin-proteasome system (UPS) is an integral part of the protein metabolism machinery mediating post-transcriptional processing and degradation of the majority of intracellular proteins. Over the past few years, remarkable progress has been made in our understanding of the role of the UPS in vascular biology and pathobiology, particularly atherosclerosis. This review reflects on the recent developments from the effects on endothelial cells and the initial stage of atherosclerosis to the effects on vascular smooth muscle and the progression stage of atherosclerosis and finally to the effects on cell viability and the complication stage of atherosclerosis. It will conclude with the integration of the available information in a synoptic view of the involvement of the UPS in atherosclerosis.