Current Perspectives in Giant Cell Arteritis: Can We Better Connect Pathogenesis and Treatment?

Giant cell arteritis (GCA) is a large-vessel vasculitis affecting elderly patients and targeting the aorta and its main branches, leading to cranial and extracranial manifestations. The mechanism behind the ischemia is a granulomatous-type inflammation with potentially critical lesions, including visual loss involving the ophthalmic artery. Despite significant progress in unraveling the pathophysiology of this disease, treatment options still rely on glucocorticoids (GCs) to overcome active vascular lesions and disease flares. However, uncertainty still revolves around the optimal dose and tapering rhythm. Few corticosteroid-sparing agents have proven useful in GCA, namely, methotrexate and tocilizumab, benefiting cumulative GC dose and relapse-free intervals. The future looks promising with regard to using other agents like abatacept and Janus-kinase inhibitors or blocking the granulocyte-macrophage colony-stimulating factor receptor.

Current Insights into Tissue Injury of Giant Cell Arteritis: From Acute Inflammatory Responses towards Inappropriate Tissue Remodeling.

Giant cell arteritis (GCA) is an autoimmune disease affecting large vessels in patients over 50 years old. It is an exemplary model of a classic inflammatory disorder with IL-6 playing the leading role. The main comorbidities that may appear acutely or chronically are vascular occlusion leading to blindness and thoracic aorta aneurysm formation, respectively. The tissue inflammatory bulk is expressed as acute or chronic delayed-type hypersensitivity reactions, the latter being apparent by giant cell formation. The activated monocytes/macrophages are associated with pronounced Th1 and Th17 responses. B-cells and neutrophils also participate in the inflammatory lesion. However, the exact order of appearance and mechanistic interactions between cells are hindered by the lack of cellular and molecular information from early disease stages and accurate experimental models. Recently, senescent cells and neutrophil extracellular traps have been described in tissue lesions. These structures can remain in tissues for a prolonged period, potentially favoring inflammatory responses and tissue remodeling. In this review, current advances in GCA pathogenesis are discussed in different inflammatory phases. Through the description of these-often overlapping-phases, cells, molecules, and small lipid mediators with pathogenetic potential are described.

Accuracy of self-reported diagnoses of polymyalgia rheumatica and giant cell arteritis in the French prospective E3N- EPIC cohort: A validation study.

OBJECTIVES: To assess the accuracy of self-reported giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) diagnoses in a large French population-based prospective cohort, and to devise algorithms to improve their accuracy. METHODS: The E3N-EPIC cohort study (Etude Epidémiologique auprès des femmes de la Mutuelle Générale de l'Education Nationale) includes 98,995 French women born between 1925 and 1950, recruited in 1990 to study risk factors of cancer and chronic diseases. They completed biennially mailed questionnaires to update their health-related information and lifestyle characteristics. In three questionnaires, women could self-report a diagnosis of GCA/PMR. Those women were additionally sent a specific questionnaire, designed to ascertain self-reported diagnoses of GCA/PMR. Four algorithms were then devised to improve their identification. Accuracies of self-reported diagnoses and of each algorithm were calculated by comparing the diagnoses with a blinded medical chart review. RESULTS: Among 98,995 participants, 1,392 women self-reported GCA/PMR. 830 women sent back the specific questionnaire, and 202 women provided medical charts. After independent review of the 202 medical charts, 87.6 % of the self-reported diagnoses of GCA/PMR were accurate. Using additional data from a specific questionnaire (diagnosis confirmation by a physician, and self-report of >3-month of glucocorticoids), and from a reimbursement database (at least two deliveries of glucocorticoids in less than 3 consecutive months) improved their accuracy (91.8 % to 92.8 %). CONCLUSION: The accuracy of self-reported diagnosis of GCA/PMR was high in the E3N-cohort but using additional data as a specific GCA/PMR questionnaire and/or corticosteroid reimbursement database further improved this accuracy. With nearly 600 detected cases of GCA/PMR, we will be able to investigate risk factors for GCA/PMR in women.

Giant Cell Arteritis after COVID-19 Vaccination with Long-Term Follow-Up: A Case Report and Review of the Literature.

Giant cell arteritis (GCA) is a chronic vasculitis that primarily affects the elderly, and can cause visual impairment, requiring prompt diagnosis and treatment. The global impact of the coronavirus disease 2019 (COVID-19) pandemic has been substantial. Although vaccination programs have been a key defense strategy, concerns have arisen regarding post-vaccination immune-mediated disorders and related risks. We present a case of GCA after COVID-19 vaccination with 2 years of follow-up. A 69-year-old woman experienced fever, headaches, and local muscle pain two days after receiving the COVID-19 vaccine. Elevated inflammatory markers were observed, and positron emission tomography (PET) revealed abnormal uptake in the major arteries, including the aorta and subclavian and iliac arteries. Temporal artery biopsy confirmed the diagnosis of GCA. Treatment consisted of pulse therapy with methylprednisolone, followed by prednisolone (PSL) and tocilizumab. Immediately after the initiation of treatment, the fever and headaches disappeared, and the inflammation markers normalized. The PSL dosage was gradually reduced, and one year later, a PET scan showed that the inflammation had resolved. After two years, the PSL dosage was reduced to 3 mg. Fourteen reported cases of GCA after COVID-19 vaccination was reviewed to reveal a diverse clinical picture and treatment response. The time from onset of symptoms to GCA diagnosis varied from two weeks to four months, highlighting the challenge of early detection. The effectiveness of treatment varied, but was generally effective similarly to that of conventional GCA. This report emphasizes the need for clinical vigilance and encourages further data collection in post-vaccination GCA cases.

[Epidemiology and pathophysiology of giant cell arteritis]. / Épidémiologie et physiopathologie de l'artérite à cellules géantes.

EPIDEMIOLOGY AND PATHOPHYSIOLOGY OF GIANT CELL ARTERITIS. Giant cell arteritis (GCA) is a granulomatous vasculitis. It affects patients over 50 years of age, predominantly women. The pathophysiology of GCA involves genetic and environmental factors leading to the development of inflammation and subsequent large artery wall remodelling, the mechanisms of which are increasingly understood. The process is thought to begin with the activation of dendritic cells in the vessel wall. These then recruit and activate CD4 T cells, inducing their proliferation and polarisation into Th1 and Th17 cells, which produce interferon-gamma (IFN-γ) and interleukin-17 (IL-17) respectively. IFN-γ activates vascular smooth muscle cells, which produce chemokines that induce the recruitment of other mononuclear cells (CD4 and CD8 T cells and monocytes). This inflammatory infiltrate, the differentiation of monocytes into macrophages induce the production of other mediators that cause remodeling of the vascular wall based on destruction of the arterial wall, neoangiogenesis and intimal hyperplasia. This remodelling leads to the ischaemic manifestations of GCA by causing stenosis or even occlusion of the affected vessels. More recently, mechanisms have been identified that allow the perpetuation of inflammation and vascular remodelling, explaining the chronic evolution of GCA.

ÉPIDÉMIOLOGIE ET PHYSIOPATHOLOGIE DE L'ARTÉRITE À CELLULES GÉANTES. L'artérite à cellules géantes (ACG) est une vascularite granulomateuse affectant les patients de plus de 50 ans, préférentiellement les femmes. La physiopathologie de l'ACG fait intervenir des facteurs génétiques et environnementaux qui conduisent à l'apparition d'une inflammation, puis d'un remodelage de la paroi des artères de gros calibre dont les mécanismes sont de mieux en mieux compris. On pense que le processus débute par l'activation des cellules dendritiques de la paroi vasculaire qui recrutent ensuite les lymphocytes T CD4, les activent et induisent leur prolifération et leur polarisation en lymphocytes Th1 et Th17, qui produisent respectivement de l'interféron gamma (IFN-γ) et de l'interleukine 17 (IL-17). L'IFN-γ active les cellules musculaires lisses vasculaires qui produisent des chimiokines induisant le recrutement d'autres cellules mononucléées (lymphocytes T CD4 et CD8 ; monocytes). Cet infiltrat inflammatoire, la différenciation des monocytes en macrophages induisent la production d'autres médiateurs qui provoquent un remodelage de la paroi vasculaire reposant sur une destruction de la paroi artérielle, une néoangiogenèse et une hyperplasie intimale. Ce remodelage conduit à la sténose, voire à l'occlusion, des vaisseaux atteints et ainsi aux manifestations ischémiques de l'ACG. Plus récemment, des mécanismes permettant d'entretenir l'inflammation et le remodelage vasculaire ont été mis en évidence et permettent d'expliquer l'évolution chronique de l'ACG.

Development of giant cell arteritis after vaccination against SARS-CoV2: A case report and literature review.

RATIONALE: Giant cell arteritis (GCA) is an autoimmune vasculitis that affects large and medium-sized blood vessels. The mRNA vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has been associated with the development of immune-mediated diseases. In this article, we present a case of GCA that developed after vaccination against SARS-CoV2. PATIENT CONCERNS: A 77-year-old man developed fever, general fatigue, and headache 1 day after the third dose of vaccination against SARS-CoV2. Nodular swelling and tenderness of the bilateral temporal arteries were observed. DIAGNOSES: Although right temporal artery biopsies were negative, the patient was diagnosed with GCA based on criteria established by the American College of Rheumatology for the classification of GCA. INTERVENTIONS: The patient received methylprednisolone 1000 mg for 3 days. This was followed by prednisolone 1 mg/kg/d, which was decreased by 10 mg every week to 30 mg. From day 16 of hospitalization, the patient received tocilizumab 162 mg/wk every other week. OUTCOMES: There was no occurrence of acute side effects. After 38 days of treatment, the condition improved and the patient was discharged from the hospital; as stated above, the dose of prednisolone was tapered to 30 mg/d. LESSONS: We experienced a case of GCA that occurred immediately after vaccination against SARS-CoV2 with an mRNA vaccine. Early signs of GCA include fever, fatigue, and headache, and often resemble those noted after vaccination against SARS-CoV2. The potential presence of GCA should be determined in individuals with persistent fever and headache after vaccination against SARS-CoV2.

Giant cell arteritis and innovative treatments.

PURPOSE OF REVIEW: Giant cell arteritis (GCA) is an idiopathic and persistent condition characterized by granulomatous vasculitis of the medium and large vessels with overlapping phenotypes, including conventional cranial arteritis and extra-cranial GCA, also known as large-vessel GCA. Vascular problems linked with large vessel involvement may partly be caused by delayed diagnosis, emphasizing the necessity of early detection and the fast beginning of appropriate therapy. Glucocorticoids are the cornerstone of treatment for GCA, but using them for an extended period has numerous, often severe, side effects. RECENT FINDINGS: clinical practice and novel discoveries on the pathogenic pathways suggest that steroid-free biologic treatments may be efficient and safe for GCA patients. SUMMARY: since now, only Tocilizumab is approved for GCA treatment, but several drugs are currently used, and ongoing trials could give both researchers and patients novel therapeutic strategies for induction, maintenance, and prevention of relapse of GCA. The aims of this work is to synthesize evidence from current studies present in scientific literature about innovative treatment of Giant cell artheritis.

Metabolic features and glucocorticoid-induced comorbidities in patients with giant cell arteritis and polymyalgia rheumatica in a Dutch and Danish cohort.

OBJECTIVES: Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are age-associated inflammatory diseases that frequently overlap. Both diseases require long-term treatment with glucocorticoids (GCs), often associated with comorbidities. Previous population-based cohort studies reported that an unhealthier metabolic profile might prevent the development of GCA. Here, we report metabolic features before start of treatment and during treatment in patients with GCA and PMR. METHODS: In the Dutch GCA/PMR/SENEX (GPS) cohort, we analysed metabolic features and prevalence of comorbidities (type 2 diabetes, hypercholesterolaemia, hypertension, obesity and cataract) in treatment-naïve patients with GCA (n=50) and PMR (n=42), and compared those with the population-based Lifelines cohort (n=91). To compare our findings in the GPS cohort, we included data from patients with GCA (n=52) and PMR (n=25) from the Aarhus cohort. Laboratory measurements, comorbidities and GC use were recorded for up to 5 years in the GPS cohort. RESULTS: Glycated haemoglobin levels tended to be higher in treatment-naïve patients with GCA, whereas high-density lipoprotein, low-density lipoprotein and cholesterol levels were lower compared with the Lifelines population. Data from the Aarhus cohort were aligned with the findings obtained in the GPS cohort. Presence of comorbidities at baseline did not predict long-term GC requirement. The incidence of diabetes, obesity and cataract among patients with GCA increased upon initiation of GC treatment. CONCLUSION: Data from the GCA and PMR cohorts imply a metabolic dysregulation in treatment-naïve patients with GCA, but not in patients with PMR. Treatment with GCs led to the rise of comorbidities and an unhealthier metabolic profile, stressing the need for prednisone-sparing targeted treatment in these vulnerable patients.

Environmental Triggers for Vasculitis.

Systemic vasculitides are autoimmune diseases characterized by vascular inflammation. Most types of vasculitis are thought to result from antigen exposure in genetically susceptible individuals, suggesting a likely role for environmental triggers in these conditions. Seasonal and geographic variations in incidence provide insight into the potential role of environmental exposures in these diseases. Many data support infectious triggers in some vasculitides, whereas other studies have identified noninfectious triggers, such as airborne pollutants, silica, smoking, and heavy metals. We review the known and suspected environmental triggers in giant cell arteritis, Takayasu arteritis, polyarteritis nodosa, Kawasaki disease, and antineutrophil cytoplasmic antibody-associated vasculitis.

Endovascular Therapy for Intracranial Giant Cell Arteritis : Systematic Review, Technical Considerations and the Effect of Intra-arterial Calcium Channel Blockers.

BACKGROUND: Giant cell arteritis (GCA) is a systemic vasculitis that may cause ischemic stroke. Rarely, GCA can present with aggressive intracranial stenoses, which are refractory to medical therapy. Endovascular treatment (EVT) is a possible rescue strategy to prevent ischemic complications in intracranial GCA but the safety and efficacy of EVT in this setting are not well-described. METHODS: A systematic literature review was performed to identify case reports and series with individual patient-level data describing EVT for intracranial GCA. The clinical course, therapeutic considerations, and technique of seven endovascular treatments in a single patient from the authors' experience are presented. RESULTS: The literature review identified 9 reports of 19 treatments, including percutaneous transluminal angioplasty (PTA) with or without stenting, in 14 patients (mean age 69.6 ± 6.3 years). Out of 12 patients 8 (66.7%) with sufficient data had > 1 pre-existing cardiovascular risk factor. All patients had infarction on MRI while on glucocorticoids and 7/14 (50%) progressed despite adjuvant immunosuppressive agents. Treatment was PTA alone in 15/19 (78.9%) cases and PTA + stent in 4/19 (21.1%). Repeat treatments were performed in 4/14 (28.6%) of patients (PTA-only). Non-flow limiting dissection was reported in 2/19 (10.5%) of treatments. The indications, technical details, and results of PTA are discussed in a single illustrative case. We report the novel use of intra-arterial calcium channel blocker infusion (verapamil) as adjuvant to PTA and as monotherapy, resulting in immediate improvement in cerebral blood flow. CONCLUSION: Endovascular treatment, including PTA with or without stenting or calcium channel blocker infusion, may be effective therapies in medically refractory GCA with intracranial stenosis.

Need and value of targeted immunosuppressive therapy in giant cell arteritis.

Despite the heterogeneity of the giant cell arteritis (GCA) at the level of clinical manifestations and the cellular and molecular players involved in its pathogenesis, GCA is still treated with standardised regimens largely based on glucocorticoids (GC). Long-term use of high dosages of GC as required in GCA are associated with many clinically relevant side effects. In the recent years, the interleukin-6 receptor blocker tocilizumab has become available as the only registered targeted immunosuppressive agent in GCA. However, immunological heterogeneity may require different pathways to be targeted in order to achieve a clinical, immunological and vascular remission in GCA. The advances in the targeted blockade of various molecular pathways involved in other inflammatory and autoimmune diseases have catalyzed the research on targeted therapy in GCA. This article gives an overview of the studies with targeted immunosuppressive treatments in GCA, with a focus on their clinical value, including their effects at the level of vascular inflammation.

Myeloproliferative neoplasms and clonal haematopoiesis in patients with giant cell arteritis: a case-control and exploratory study.

OBJECTIVES: GCA is a large vessel vasculitis for which triggering factors remain unknown. Clonal haematopoiesis (CH) was associated with atherosclerosis through the induction of inflammation in myeloid cells, and data suggest that CH expansion and inflammation may support each other to induce a pro-inflammatory loop. Our objective was to describe the impact of JAK2p.V617F-mutated myeloproliferative neoplasms (MPNs) on GCA and to screen MPN-free patients for CH mutations. METHODS: We performed a retrospective case-control study comparing the characteristics of 21 GCA patients with MPN and 42 age- and gender-matched GCA patients without MPN. Also, 18 GCA patients were screened for CH through next-generation sequencing (NGS). RESULTS: The most frequent associated MPN was essential thrombocythaemia (ET; n = 11). Compared with controls, GCA patients with MPN had less-frequent cephalic symptoms (71.4 vs 97.6%; P = 0.004) and higher platelet counts at baseline [485 × 109/l (interquartile range 346-586) vs 346 (296-418); P = 0.02]. There was no difference between groups for other clinical features. Overall survival was significantly shorter in patients with MPN compared with controls [hazard ratio 8.2 (95% CI 1.2, 56.6); P = 0.03]. Finally, screening for CH using NGS in 15 GCA patients without MPN revealed CH in 33%. CONCLUSION: GCA patients with MPN display higher platelet counts and shorter overall survival than controls. This association is not fortuitous, given the possible pathophysiological relationship between the two diseases. CH was found in one-third of GCA patients, which may be higher than the expected prevalence for a similar age, and should be confirmed in a larger cohort.

A Case of Post-COVID-19-Associated Paracentral Acute Middle Maculopathy and Giant Cell Arteritis-Like Vasculitis.

ABSTRACT: A 47-year-old man with a history of COVID-19 infection 2 months before presentation, presented with a scotoma of the paracentral visual field of the right eye. After thorough testing and evaluation, a diagnosis of paracentral acute middle maculopathy (PAMM) was established. Two months later, the patient developed temporal headache and jaw claudication. High-dose steroids were initiated, and workup for giant cell arteritis (GCA) was undertaken. The patient experienced resolution of the symptoms within 24 hours of steroid initiation. ESR, CRP, and temporal artery biopsy results were normal, although all were obtained more than 2 weeks after steroid initiation. To the best of our knowledge, our patient represents the first individual to date to potentially implicate COVID-19 in both small and large vessel vasculitis in the ophthalmic setting.

Dysregulated Expression of Arterial MicroRNAs and Their Target Gene Networks in Temporal Arteries of Treatment-Naïve Patients with Giant Cell Arteritis.

In this study, we explored expression of microRNA (miR), miR-target genes and matrix remodelling molecules in temporal artery biopsies (TABs) from treatment-naïve patients with giant cell arteritis (GCA, n = 41) and integrated these analyses with clinical, laboratory, ultrasound and histological manifestations of GCA. NonGCA patients (n = 4) served as controls. GCA TABs exhibited deregulated expression of several miRs (miR-21-5p, -145-5p, -146a-5p, -146b-5p, -155-5p, 424-3p, -424-5p, -503-5p), putative miR-target genes (YAP1, PELI1, FGF2, VEGFA, KLF4) and matrix remodelling factors (MMP2, MMP9, TIMP1, TIPM2) with key roles in Toll-like receptor signaling, mechanotransduction and extracellular matrix biology. MiR-424-3p, -503-5p, KLF4, PELI1 and YAP1 were identified as new deregulated molecular factors in GCA TABs. Quantities of miR-146a-5p, YAP1, PELI1, FGF2, TIMP2 and MMP9 were particularly high in histologically positive GCA TABs with occluded temporal artery lumen. MiR-424-5p expression in TABs and the presence of facial or carotid arteritis on ultrasound were associated with vision disturbances in GCA patients. Correlative analysis of miR-mRNA quantities demonstrated a highly interrelated expression network of deregulated miRs and mRNAs in temporal arteries and identified KLF4 as a candidate target gene of deregulated miR-21-5p, -146a-5p and -155-5p network in GCA TABs. Meanwhile, arterial miR and mRNA expression did not correlate with constitutive symptoms and signs of GCA, elevated markers of systemic inflammation nor sonographic characteristics of GCA. Our study provides new insights into GCA pathophysiology and uncovers new candidate biomarkers of vision impairment in GCA.