Decrease in circulating dendritic cell precursors in patients with peripheral artery disease

Autoimmune diseases and cardiovascular risk: Mendelian randomization analysis for the impact of 19 autoimmune diseases on 14 cardiovascular conditions

Backgroud

Autoimmune diseases (AIDs) have been associated with various cardiovascular diseases (CVDs) in observational data. However, the causality of these associations remains uncertain. Therefore, a systematic assessment of the impact of AIDS on cardiovascular risk is required.

Results

We assessed the impact of 19 common AIDs on 14 CVDs using bidirectional Mendelian randomization (MR). Celiac disease (odds ratio [OR] = 2.949, 95 % confidence interval [CI]: 1.111-7.827, P = 0.030) and type 1 diabetes mellitus (T1DM) (OR = 1.044, 95 % CI: 1.021-1.068, P = 1.82e-4) were associated with an increased risk of peripheral arterial disease (PAD). Additionally, celiac disease was linked to an increased risk of arrhythmia (OR = 1.008, 95 % CI: 1.002-1.013, P = 0.004), multiple sclerosis to venous thromboembolism (OR = 1.001, 95 % CI: 1.000-1.001, P = 0.010), and psoriasis to heart failure (OR = 1.048, 95 % CI: 1.021-1.077, P = 0.001). Sensitivity analyses were conducted to enhance the robustness of these findings. Predominantly, immune response and inflammation-related pathways were enriched in the aforementioned associations. Mediation analysis identified human leukocyte antigen-DR positive myeloid dendritic cells as partially mediating the effect of T1DM on PAD, with a mediated proportion of 16.61 % (P = 0.028). Potential therapeutic agents, such as tumor necrosis factor-alpha inhibitors and interferon, may have efficacy in treating AID-related CVDs.

Conclusions

This study presents genetic evidence of certain AIDs impacting specific CVDs and identifies potential mediators and drugs.

Insulin resistance and obesity affect monocyte-derived dendritic cell phenotype and function

AIM

Cardiovascular disease (CVD) is prevalent in women after menopause, which may be associated with obesity, insulin resistance and metaflammation. Despite the recognized role of immunological mechanisms in vascular remodeling, the role of dendritic cells (DCs) is still unclear. The aim was to characterize monocyte-derived DCs (Mo-DC) in post-menopausal patients with type 2 diabetes (T2DM) and obese woman, without clinical manifestations of atherosclerosis.

METHODS

Obese post-menopausal women with or without T2DM were enrolled and were compared to age-matched healthy women. DCs obtained from patients were phenotypically and functionally characterized by flow cytometry and mixed lymphocyte reaction. MRNA integrins expression was assessed by real time RT-PCR; circulating fetuin-A and adiponectin levels were measured by ELISA.

RESULTS

Phenotypic dysregulation of Mo-DC reported was related to a defective allogenic lymphocyte stimulation and to an increased mRNA of CD11c, CD18 and DC-SIGN/CD209 which regulate their adhesion to vascular wall cells. Fetuin-A and adiponectin levels were significantly altered and negatively correlated. Hyperglycaemia significantly impaired CD14+ transdifferentiation into Mo-DC.

CONCLUSIONS

These data show a dysfunction of Mo-DCs obtained from precursors isolated from T2DM obese post-menopausal woman without any documented clinical CV event. Association of obesity to diabetes seems to worsen DC's phenotype and function and increase vascular inflammation.

Cellular inflammation in pulmonary hypertension: Detailed analysis of lung and right ventricular tissue, circulating immune cells and effects of a dual endothelin receptor antagonist

Growing evidence suggests that inflammation is crucially involved in the pathogenesis of pulmonary hypertension (PH) and consecutive right heart failure. The present study analyzed the inflammatory response in lung and right ventricle in a rat model of PH and evaluated the effects of the dual endothelin receptor antagonist (ERA) Macitentan. PH was induced by monocrotalin (60 mg/kg body weight s.c.) in Sprague-Dawley rats (PH, n = 10) and compared to healthy controls (CON, n = 10) as well as monocrotalin-induced, macitentan-treated rats (THER, n = 10). Detection of Dendritic cells (DCs), regulatory T cells (Tregs) and others as well as RT-PCR based inflammatory gene expression analysis were performed. Circulating DCs and Tregs were quantified by flow cytometry in the rat model and in PH patients (n = 70) compared to controls (n = 52). Inflammatory cells were increased in lung and right ventricular tissue, whereas DCs and Tregs were decreased in blood. Expression of 17 genes in the lung and 20 genes in the right ventricle were relevantly (>2.0 fold) regulated in the PH group. These effects were, at least in part, attenuated in response to Macitentan treatment. In humans as well as rats, immune cells showed significant correlations to clinical, echocardiographic, and haemodynamic parameters. PH is accompanied by a distinct inflammatory response in lung and right but not left ventricular tissue attenuated by Macitentan. Correlations of circulating DCs as well as tissue resident immune cells with parameters reflecting right ventricular function raise the idea of both, promising biomarkers and novel treatment strategies.

Immunobiology of Atherosclerosis: A Complex Net of Interactions

Cardiovascular disease is the leading cause of mortality worldwide, and atherosclerosis the principal factor underlying cardiovascular events. Atherosclerosis is a chronic inflammatory disease characterized by endothelial dysfunction, intimal lipid deposition, smooth muscle cell proliferation, cell apoptosis and necrosis, and local and systemic inflammation, involving key contributions to from innate and adaptive immunity. The balance between proatherogenic inflammatory and atheroprotective anti-inflammatory responses is modulated by a complex network of interactions among vascular components and immune cells, including monocytes, macrophages, dendritic cells, and T, B, and foam cells; these interactions modulate the further progression and stability of the atherosclerotic lesion. In this review, we take a global perspective on existing knowledge about the pathogenesis of immune responses in the atherosclerotic microenvironment and the interplay between the major innate and adaptive immune factors in atherosclerosis. Studies such as this are the basis for the development of new therapies against atherosclerosis.

Deficiency of β-Arrestin 2 in Dendritic Cells Contributes to Autoimmune Diseases

Altered migration and immune responses of dendritic cells (DCs) lead to inflammatory and autoimmune diseases. Our studies demonstrated that β-arrestin 2 deficiency promoted migration and cytokine production of mouse bone marrow-derived DCs. We further found that β-arrestin 2 directly interacted with Zbtb46, a DC-specific transcription factor. What's more, our results suggested that the interaction between β-arrestin 2 and Zbtb46 might negatively regulate DC migration. Using RNA sequencing, we indicated that genes CD74, NR4A1, and ZFP36 might be the target genes regulated by the interaction between β-arrestin 2 and Zbtb46. Mice with selective deficiency of β-arrestin 2 in DCs developed severer experimental autoimmune encephalomyelitis with more DC infiltration in the CNS and increased IL-6 in serum. In the systemic lupus erythematosus mice model, Arrb2^fl/fl Itgax-cre⁺ mice were prone to exacerbation of lupus nephritis with a higher level of IL-6 and DC accumulation. Taken together, our study identified β-arrestin 2 as a new regulator of DC migration and immune properties, providing new insights into the mechanisms underlying the development of autoimmune disease.

Inflammation in Right Ventricular Failure: Does It Matter?

Right ventricular (RV) failure is a common consequence of acute and chronic RV overload of pressure, such as after pulmonary embolism and pulmonary hypertension. It has been recently realized that symptomatology and survival of patients with pulmonary hypertension are essentially determined by RV function adaptation to increased afterload. Therefore, improvement of RV function and reversal of RV failure are treatment goals. Currently, the pathophysiology and the pathobiology underlying RV failure remain largely unknown. A better understanding of the pathophysiological processes involved in RV failure is needed, as there is no proven treatment for this disease at the moment. The present review aims to summarize the current understanding of the pathogenesis of RV failure, focusing on inflammation. We attempt to formally emphasize the importance of inflammation and associated representative inflammatory molecules and cells in the primum movens and development of RV failure in humans and in experimental models. We present inflammatory biomarkers and immune mediators involved in RV failure. We focus on inflammatory mediators and cells which seem to correlate with the deterioration of RV function and also explain how all these inflammatory mediators and cells might impact RV function adaptation to increased afterload. Finally, we also discuss the evidence on potential beneficial effects of targeted anti-inflammatory agents in the setting of acute and chronic RV failure.

Analysis of novel cardiovascular biomarkers in patients with peripheral artery disease

BACKGROUND

Peripheral artery disease (PAD) is a common form of manifestation of atherosclerosis. PAD has a considerable impact on morbidity, hospitalization rates and health-care costs. Biomarkers have been introduced in many cardiovascular disease entities over the last years. However, an analysis on the correlation of biomarker levels and PAD is still lacking.

METHODS

A total of 106 patients were enrolled in this current study, 51 that were diagnosed with PAD and 55 with excluded coronary and peripheral artery disease as controls. During outpatient visits, plasma samples of all patients were obtained and analyzed for sST2 (hemodynamics and inflammation), galectin-3 (fibrosis and remodeling), GDF-15 (remodeling and inflammation), suPAR (inflammation), and fetuin-A (vascular calcification) by use of ELISA after informed consent.

RESULTS

Compared with controls, patients with PAD showed significantly higher levels of sST2 (5248 vs. 7503 pg/mL, P<0.001), suPAR (2267 vs. 2414 pg/mL, P=0.02), galectin-3 (2795 vs. 4494 pg/mL, P<0.001), and GDF-15 (549 vs. 767 pg/mL, P<0.001). Fetuin-A showed a trend towards lower levels in patients with PAD (117 vs. 100 ng/mL, P=0.119).

CONCLUSIONS

Circulating levels of sST2, suPAR, galectin-3, and GDF-15 were significantly elevated in PAD patients. In contrast, fetuin-A levels showed a decrease in PAD patients indicating increased vascular calcification. Thus, by incorporating different pathophysiological processes present in PAD, tested novel biomarkers facilitate a more precise diagnosis as well as a more accurate evaluation of disease severity and progression.

Dendritic cell migration in health and disease

Dendritic cells (DCs) are potent and versatile antigen-presenting cells, and their ability to migrate is key for the initiation of protective pro-inflammatory as well as tolerogenic immune responses. Recent comprehensive studies have highlighted the importance of DC migration in the maintenance of immune surveillance and tissue homeostasis, and also in the pathogenesis of a range of diseases. In this Review, we summarize the anatomical, cellular and molecular factors that regulate the migration of different DC subsets in health and disease. In particular, we focus on new insights concerning the role of migratory DCs in the pathogenesis of diseases of the skin, intestine, lung, and brain, as well as in autoimmunity and atherosclerosis.