Inflammatory Cell Composition and Immune-Related microRNA Signature of Temporal Artery Biopsies From Patients With Giant Cell Arteritis

Is Giant Cell Arteritis Associated with Increased Risk of Cardiovascular Disease? A Meta-Analysis

Giant cell arteritis (GCA) is the most common form of vasculitis in individuals aged >50 years. While it has been hypothesized that GCA increases the risk of adverse cardiovascular events, existing literature presents conflicting findings. This meta-analysis aims to examine the risks of myocardial infarction (MI), stroke, and peripheral arterial disease (PAD) in patients with GCA. A comprehensive search of major bibliographic databases, including PubMed, EMBASE, Google Scholar, SCOPUS, and Web of Science, was conducted to identify studies on cardiovascular risks in GCA patients up to November 1, 2024. The RevMan (version 5.4) software was used with a random-effects model to calculate pooled hazard ratios (HR) with 95% confidence intervals (CI), using Der-Simonian and Laird's inverse-variance random-effects method. The meta-analysis included 10 studies with 518,402 participants (28,707 GCA patients and 489,695 controls). GCA was associated with a significantly increased risk of MI (HR, 1.74; 95% CI, 1.34-2.25; P < 0.0001), stroke (HR, 1.43; 95% CI, 1.33-1.54; P < 0.00001), and PAD (HR, 1.98; 95% CI, 1.53-2.57; P < 0.00001). This meta-analysis shows that GCA patients are at a significantly higher risk of MI, stroke, and PAD compared with controls. Further prospective studies are needed to confirm these findings, as early cardiovascular risk management could reduce the risk of major adverse cardiovascular events.

Current state of epigenetics in giant cell arteritis: Focus on microRNA dysregulation

Giant cell arteritis (GCA) is a primary systemic vasculitis affecting the elderly, characterized by a granulomatous vessel wall inflammation of large- and medium-sized arteries. The immunopathology of GCA is complex, involving both the innate and adaptive arms of the immune system, where a maladaptive inflammatory-driven vascular repair process ultimately results in vessel wall thickening, intramural vascular smooth muscle cell proliferation, neovascularization and vessel lumen occlusion, which can lead to serious ischemic complications such as visual loss and ischemic stroke. Over the past decade, microRNA (miRNA) dysregulation has been highlighted as an important contributing factor underlying the pathogenesis of GCA. Since current understanding of miRNA involvement in GCA remains largely based on extrapolation of previously determined miRNA functions in vitro or in loss- or gain-of-function studies, an overall insight into the role of miRNA alteration in GCA pathophysiology remains limited. In this narrative review, we summarize the current knowledge on aberrantly expressed miRNAs in GCA and thoroughly discuss the impact of their altered regulatory role in the context of GCA setting. Furthermore, we address challenges and future perspectives in utilization of miRNA-based diagnostic and prognostic biomarkers of GCA in clinical settings.

Use of high-plex data provides novel insights into the temporal artery processes of giant cell arteritis

Objective

To identify the key coding genes underlying the biomarkers and pathways associated with giant cell arteritis (GCA), we performed an in situ spatial profiling of molecules involved in the temporal arteries of GCA patients and controls. Furthermore, we performed pharmacogenomic network analysis to identify potential treatment targets.

Methods

Using human formalin-fixed paraffin-embedded temporal artery biopsy samples (GCA, n = 9; controls, n = 7), we performed a whole transcriptome analysis using the NanoString GeoMx Digital Spatial Profiler. In total, 59 regions of interest were selected in the intima, media, adventitia, and perivascular adipose tissue (PVAT). Differentially expressed genes (DEGs) (fold-change > 2 or < -2, p-adjusted < 0.01) were compared across each layer to build a spatial and pharmacogenomic network and to explore the pathophysiological mechanisms of GCA.

Results

Most of the transcriptome (12,076 genes) was upregulated in GCA arteries, compared to control arteries. Among the screened genes, 282, 227, 40, and 5 DEGs were identified in the intima, media, adventitia, and PVAT, respectively. Genes involved in the immune process and vascular remodeling were upregulated within GCA temporal arteries but differed across the arterial layers. The immune-related functions and vascular remodeling were limited to the intima and media.

Conclusion

This study is the first to perform an in situ spatial profiling characterization of the molecules involved in GCA. The pharmacogenomic network analysis identified potential target genes for approved and novel immunotherapies.

The role of autoimmunity and autoinflammation in giant cell arteritis: A systematic literature review

Giant cell arteritis is the most common form of large vessel vasculitis and preferentially involves large and medium-sized arteries in patients over the age of 50. Aggressive wall inflammation, neoangiogenesis and consecutive remodeling processes are the hallmark of the disease. Though etiology is unknown, cellular and humoral immunopathological processes are well understood. Matrix metalloproteinase-9 mediated tissue infiltration occurs through lysis of basal membranes in adventitial vessels. CD4+ cells attain residency in immunoprotected niches, differentiate into vasculitogenic effector cells and enforce further leukotaxis. Signaling pathways involve the NOTCH1-Jagged1 pathway opening vessel infiltration, CD28 mediated T-cell overstimulation, lost PD-1/PD-L1 co-inhibition and JAK/STAT signaling in interferon dependent responses. From a humoral perspective, IL-6 represents a classical cytokine and potential Th-cell differentiator whereas interferon-γ (IFN- γ) has been shown to induce chemokine ligands. Current therapies involve glucocorticoids, tocilizumab and methotrexate application. However, new agents, most notably JAK/STAT inhibitors, PD-1 agonists and MMP-9 blocking substances, are being evaluated in ongoing clinical trials.

Evaluation of Arterial Histopathology and microRNA Expression That Underlie Ultrasonography Findings in Temporal Arteries of Patients with Giant Cell Arteritis

The aim of this study was to assess the interrelation between vascular ultrasonography (US) findings, histopathological data, and the expression of selected dysregulated microRNAs (miRNAs) in giant cell arteritis (GCA). The study included data on the clinical parameters, US measurements, and temporal artery biopsies (TABs) of 46 treatment-naïve patients diagnosed with GCA and 22 age-matched non-GCA patient controls. We performed a comprehensive comparative and correlation analysis along with generation of receiver operating characteristic (ROC) curves to ascertain the diagnostic performance of US examination parameters and selected miRNAs for GCA diagnosis. We showed significant differences in the US-measured intima-media thickness of the temporal arteries, the presence of a halo sign, and the presence of luminal stenosis between GCA-positive/TAB-positive, GCA-positive/TAB-negative, and non-GCA patients. Correlation analysis revealed significant associations between several histopathological parameters, US-measured intima-media thickness, and the halo sign. We found that the significant overexpression of miR-146b-5p, miR-155-5p, miR-511-5p, and miR-21-5p, and the under-expression of the miR-143/145 cluster, miR-30a-5p, and miR-125a-5p, coincides and is associated with the presence of a halo sign in patients with GCA. Notably, we determined a high diagnostic performance of miR-146b-5p, miR-21-3p, and miR-21-5p expression profiles in discriminating GCA patients from non-GCA controls, suggesting their potential utilization as putative biomarkers of GCA. Taken together, our study provides an insight into the US-based diagnostic evaluation of GCA by revealing the complex interrelation of clearly defined image findings with underlying vascular immunopathology and altered arterial tissue-specific miRNA profiles.

An Updated Review of Cardiovascular Events in Giant Cell Arteritis

Giant cell arteritis (GCA) is a systemic vasculitis with a direct and indirect increased risk of acute and chronic vascular events, affecting large and medium vessels, and responsible for most of the morbidity and mortality of this disease. We aimed in this review to provide an updated synthesis of knowledge regarding cardiovascular events observed in GCA. By definition, GCA patients are over 50 and often over 70 years old, and subsequently also present age-related cardiovascular risk factors. In addition, the systemic and vascular inflammation as well as glucocorticoids (GC) probably contribute to an accelerated atherosclerosis and to vascular changes leading to arterial stenoses and aortic dilations and/or dissections. GCA-related ischemic complications, especially ophthalmologic events, stroke or myocardial infarcts are mostly observed within the first months after the diagnosis, being mainly linked to the vasculitic process. Conversely, aortic complications, including dilations or dissections, generally occur several months or years after the diagnosis, mainly in patients with large-vessel vasculitis. In these patients, other factors such as atherosclerosis, GC-related endothelial damage and vascular wall remodeling/healing probably contribute to the vascular events. GCA management includes the detection and treatment of these previous and newly induced cardiovascular risk factors. Hence, the use of cardiovascular treatments (e.g., aspirin, anticoagulation, statins, anti-hypertensive treatments) should be evaluated individually. Aortic structural changes require regular morphologic evaluations, especially in patients with previous aortitis. The initial or secondary addition of immunosuppressants, especially tocilizumab, an anti-IL-6 receptor antibody, is discussed in patients with GCA-related cardiovascular complications and, more consensually, to limit GC-mediated comorbidities.