Giant Cell Arteritis

Unraveling the Links between Chronic Inflammation, Autoimmunity, and Spontaneous Cervicocranial Arterial Dissection

Advances in imaging techniques have led to a rise in the diagnosis of spontaneous cervicocranial arterial dissection (SCCAD), which is now considered a common cause of stroke in young adults. However, our understanding of the pathophysiological mechanisms underlying SCCAD remains limited. Prior studies have proposed various factors contributing to arterial wall weakness or stress as potential causes for SCCAD. A combination of biopsies, case reports, and case-control studies suggests that inflammatory changes and autoimmunity may play roles in the cascade of events leading to SCCAD. In this review, we examine the close relationship between SCCAD, chronic inflammation, and autoimmune diseases, aiming to explore potential underlying pathophysiological mechanisms connecting these conditions. While some relevant hypotheses and studies exist, direct evidence on this topic is still relatively scarce. Further investigation of the underlying mechanisms in larger clinical cohorts is needed, and the exploration of animal models may provide novel insights.

Perspective for Discovery of Small Molecule IL-6 Inhibitors through Study of Structure–Activity Relationships and Molecular Docking

Interleukin-6 (IL-6) is a proinflammatory cytokine that plays a key role in the pathogenesis and physiology of inflammatory and autoimmune diseases, such as coronary heart disease, cancer, Alzheimer's disease, asthma, rheumatoid arthritis, and most recently COVID-19. IL-6 and its signaling pathway are promising targets in the treatment of inflammatory and autoimmune diseases. Although, anti-IL-6 monoclonal antibodies are currently being used in clinics, huge unmet medical needs remain because of the high cost, administration-related toxicity, lack of opportunity for oral dosing, and potential immunogenicity of monoclonal antibody therapy. Furthermore, nonresponse or loss of response to monoclonal antibody therapy has been reported, which increases the importance of optimizing drug therapy with small molecule drugs. This work aims to provide a perspective for the discovery of novel small molecule IL-6 inhibitors by the analysis of the structure-activity relationships and computational studies for protein-protein inhibitors targeting the IL-6/IL-6 receptor/gp130 complex.

Neurological complications of giant cell arteritis: A study of 15 cases and a review of the literature

BACKGROUND

Giant cell arteritis (GCA) is considered a neuro-ophthalmologic emergency. New-onset headache in patients aged 50 years and above with elevated erythrocyte sedimentation rate should prompt evaluation for GCA.

MATERIAL AND METHODS

Retrospective study of 15 patients presenting with GCA from 1991 to 2008 at the Mohamed V Military hospital at Rabat and Avicenne Military hospital of Marrakech.

RESULTS

Fifteen cases were recorded, with female predominance (male to female ratio 2:3) and a mean age of 63 years (range: 55-83 years). All patients (100%) presented with headache. The headache was isolated in 20% of cases and neuro-ophthalmic complications were found in 73% of cases. Biopsy was conclusive for GCA in 67% of cases and all of our patients were placed on steroids with spectacular improvement.

CONCLUSION

New-onset headache in patients aged 50 years and above should prompt evaluation for GCA. Steroids, especially during the acute phase, must be started urgently to avoid irreversible neurological impairment.

[Acute ischemic optic nerve disease: Pathophysiology, clinical features and management (French translation of the article)]

Ischemic optic neuropathies are among the leading causes of severe visual acuity loss in people over 50 years of age. They constitute a set of various entities that are clinically, etiologically and therapeutically different. Anatomically, it is necessary to distinguish anterior and posterior forms. From an etiological point of view, the diagnosis of the arteritic form due to giant cell arteritis requires emergent management to prevent blindness and even death in the absence of prompt corticosteroid treatment. When this diagnosis has been ruled out with certainty, non-arteritic ischemic optic neuropathies represent a vast etiological context that in the majority of cases involves a local predisposing factor (small optic nerves, disc drusen) with a precipitating factor (severe hypotension, general anesthesia or dialysis) in a context of vascular disease (sleep apnea syndrome, hypertension, diabetes, etc.). In the absence of specific available treatment, it is the responsibility of the clinician to identify the risk factors involved, in order to reduce the risk of contralateral recurrence that may occur even several years later. Due to their complexity, these pathologies are the subject of debates regarding both the pathophysiological and therapeutic perspectives; this review aims to provide a synthesis of validated knowledge while discussing controversial data.

Acute ischemic optic nerve disease: Pathophysiology, clinical features and management

Ischemic optic neuropathies are among the leading causes of severe visual acuity loss in people over 50 years of age. They constitute a set of various entities that are clinically, etiologically and therapeutically different. Anatomically, it is necessary to distinguish anterior and posterior forms. From an etiological point of view, the diagnosis of the arteritic form due to giant cell arteritis requires emergent management to prevent blindness and even death in the absence of prompt corticosteroid treatment. When this diagnosis has been ruled out with certainty, non-arteritic ischemic optic neuropathies represent a vast etiological context that in the majority of cases involves a local predisposing factor (small optic nerves, disc drusen) with a precipitating factor (severe hypotension, general anesthesia or dialysis) in a context of vascular disease (sleep apnea syndrome, hypertension, diabetes, etc.). In the absence of specific available treatment, it is the responsibility of the clinician to identify the risk factors involved, in order to reduce the risk of contralateral recurrence that may occur even several years later. Due to their complexity, these pathologies are the subject of debates regarding both the pathophysiological and therapeutic perspectives; this review aims to provide a synthesis of validated knowledge while discussing controversial data.

Cardiovascular magnetic resonance in the diagnosis and management of cardiac and vascular involvement in the systemic vasculitides

PURPOSE OF REVIEW

Cardiac manifestations in systemic vasculitides, either primary or secondary due to infection, malignancy or autoimmune rheumatic diseases may be life-threatening. Cardiovascular (CVD) magnetic resonance (CMR) has been recently proposed as an ideal noninvasive tool to evaluate systemic vasculitides. In the present article, we present an overview of CMR in the diagnosis and follow-up of cardiac involvement in systemic vasculitides.

RECENT FINDINGS

CMR is a noninvasive, nonradiating modality, capable to assess cardiac function, perfusion and tissue characterization that can be of great diagnostic value in both primary and secondary systemic vasculitides. It has been already documented that CMR is superior to other imaging modalities, because it has great versatility and higher spatial resolution that allows the detection of early CVD phenomena occurring during systemic vasculitides. Magnetic resonance angiography and oedema-fibrosis imaging detect early CVD involvement such as acute and/or chronic inflammation, coronary macro-micro-circulation abnormalities and/or small vessel vasculitis.

SUMMARY

CMR due to its great versatility gives valuable information about cardiac function, perfusion, type of fibrosis and vascular integrity that may significantly contribute to treatment decisions beyond vascular scores, other disease activity or severity indices or the acute phase response.

Giant cell arteritis: early diagnosis is key

Giant cell arteritis (GCA) is an inflammatory vasculitis typically affecting elderly that can potentially cause vision loss. Studies have demonstrated that early recognition and initiation of treatment can improve visual prognosis in patients with GCA. This review addresses the benefits of early diagnosis and treatment, and discusses the available treatment options to manage the disease.

Characterization of serological markers of healed/healing arteritis and giant cell arteritis

OBJECTIVE

Temporal artery biopsy (TAB) is the gold standard for confirming the diagnosis of giant cell arteritis (GCA) when positive. However, the clinical significance of healed/healing (HH) arterial injury on TAB is not well understood. The purpose of this study was to evaluate the clinical significance of this finding on TAB by determining its association with seromarkers typically predictive of GCA.

DESIGN

Single-centre, retrospective, investigational cohort study.

PARTICIPANTS

A total of 385 consecutive TABs for clinical suspicion of GCA between January 2009 and January 2016.

METHODS

Elevations in erythrocyte sedimentation rate, C-reactive protein, and platelet count were compared between patients with negative TAB, GCA-positive TAB, and HH arterial injury using statistical trend testing. Odds ratios of seromarker elevations for HH arterial injury versus GCA were calculated.

RESULTS

Seventy-six GCA-positive, 69 HH, and 240 negative TABs were identified. Mantel-Haenszel tests of trend indicated that platelets >400 000/µL (p < 0.01), erythrocyte sedimentation rate ≥50 mm/hr (p < 0.01), and C-reactive protein ≥24.5 mg/L (p < 0.01) occurred with intermediate frequency in the HH TAB group. The odds of HH TAB were 3.6 times greater (95% CI 1.5-8.5) with platelets >400 000/µL.

CONCLUSION

HH arterial injury is a heterogenous group that requires treatment in the appropriate clinical setting. From our study, we found that the HH group is intermediate between GCA-positive and GCA-negative biopsy with respect to serology markers only. Thrombocytosis is an independent predictor of HH TAB. With further studies, this marker may be considered when making treatment decisions. Further studies are required to better understand this entity.

The Treatment of Giant Cell Arteritis

OPINION STATEMENT

Giant cell arteritis (GCA) is a systemic inflammatory vasculitis affecting medium and large vessels with potentially sight and life-threatening complications. Early diagnosis and prompt treatment are imperative in order to prevent vision loss and progression of the disease. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are inflammatory markers which are elevated in the majority of patients and support the diagnosis of GCA among patients who present with typical symptoms. GCA is confirmed with superficial temporal artery biopsy which demonstrates characteristic pathological findings. Treatment of suspected ophthalmic involvement must be initiated urgently, even when diagnostic studies are pending. High dose corticosteroid therapy is the mainstay of treatment and is administered either intravenously or orally to prevent further vision loss and treat systemic vasculitis. Oral corticosteroid therapy is required for months to years with careful follow-up and periodic laboratory evaluations with ESR and CRP. Corticosteroids are tapered gradually over months and may be associated with complications such as hypertension, diabetes mellitus, osteoporosis, psychosis, peptic ulcer disease, and infection. Supplementation with calcium, vitamin D, bisphosphonate therapy, antimicrobial prophylaxis, and initiation of a proton pump inhibitor or Histamine H2-receptor antagonist should be considered. Recurrence of inflammation is common in GCA and necessitates an escalation of corticosteroid dose. Adjunctive immunomodulatory therapy may be considered in patients experiencing relapsing inflammation despite high doses of corticosteroids or those with corticosteroid-induced complications. Emerging evidence for adjunctive therapy with tocilizumab, methotrexate, aspirin, angiotensin receptor blockers, and statins is encouraging and may lead to a more mainstream role for these therapies among patients with GCA.

The Role of Integrins αMβ2 (Mac-1, CD11b/CD18) and αDβ2 (CD11d/CD18) in Macrophage Fusion

The subfamily of β2 integrins is implicated in macrophage fusion, a hallmark of chronic inflammation. Among β2 family members, integrin Mac-1 (αMβ2, CD11b/CD18) is abundantly expressed on monocyte/macrophages and mediates critical adhesive reactions of these cells. However, the role of Mac-1 in macrophage fusion leading to the formation of multinucleated giant cells remains unclear. Moreover, the role of integrin αDβ2 (CD11d/CD18), a receptor with recognition specificity overlapping that of Mac-1, is unknown. We found that multinucleated giant cells are formed in the inflamed mouse peritoneum during the resolution phase of inflammation, and their numbers were approximately twofold higher in wild-type mice than in Mac-1(-/-) mice. Analyses of isolated inflammatory peritoneal macrophages showed that IL-4-induced fusion of Mac-1-deficient cells was strongly reduced compared with wild-type counterparts. The examination of adhesive reactions known to be required for fusion showed that spreading, but not adhesion and migration, was reduced in Mac-1-deficient macrophages. Fusion of αDβ2-deficient macrophages was also significantly decreased, albeit to a smaller degree. Deficiency of intercellular adhesion molecule 1, a counter-receptor for Mac-1 and αDβ2, did not alter the fusion rate. The results indicate that both Mac-1 and αDβ2 support macrophage fusion with Mac-1 playing a dominant role and suggest that Mac-1 may mediate cell-cell interactions with a previously unrecognized counter-receptor(s).

Treatment of giant cell arteritis

PURPOSE OF REVIEW

Giant cell arteritis (GCA) remains a potentially blinding inflammatory vasculitis of the elderly. Because prolonged doses of corticosteroids remain the best established treatment, side-effects during treatment are common and potentially serious. This review addresses the challenges clinicians face in managing this disease.

RECENT FINDINGS

High-dose corticosteroids with slow tapering and close monitoring are the mainstay of treatment. Investigations into adjunctive treatment have yet to establish other agents as beneficial, but further research is ongoing with some promising results.

SUMMARY

GCA represents a challenging illness to clinicians because of its potential for causing blindness and the need for prolonged high doses of corticosteroids with their many complications.

Cardiac manifestations of rheumatological conditions: a narrative review

Cardiovascular diseases are common in systemic rheumatologic diseases. They can be presented at the time of diagnosis or after diagnosis. The cardiac involvements can be the first presentation of rheumatologic conditions. It means that a patient with rheumatologic disease may go to a cardiologist when attacked by this disease at first. These manifestations are very different and involve different structures of the heart, and they can cause mortality and morbidity of patients with rheumatologic diseases. Cardiac involvements in these patients vary from subclinical to severe manifestations. They may need aggressive immunosuppressive therapy. The diagnosis of these conditions is very important for choosing the best treatment. Premature atherosclerosis and ischemic heart disease are increased in rheumatoid arthritis and systemic lupus erythematosus, and may be causes of mortality among them. The aggressive control of systemic inflammation in these diseases can reduce the risk of cardiovascular disease especially ischemic heart disease. Although aggressive treatment of primary rheumatologic diseases can decrease mortality rate and improve them, at this time, there are no specific guidelines and recommendations, to include aggressive control and prevention of traditional risk factors, for them.

Cholate-containing high-fat diet induces the formation of multinucleated giant cells in atherosclerotic plaques of apolipoprotein E-/- mice

OBJECTIVE

To determine the role of multinucleated giant cells (MGCs) in cardiovascular diseases.

METHODS AND RESULTS

MGCs are a hallmark of giant cell arteritis. They are also described in atherosclerotic plaques from aortic aneurysms and carotid and coronary arteries. Herein, we demonstrate that the cholate-containing Paigen diet yields many MGCs in atherosclerotic plaques of apolipoprotein E-/- mice. These mice revealed a 4-fold increase in MGC numbers when compared with mice on a Western or Paigen diet without cholate. Most of the MGCs stained intensively for cathepsin K and were located at fibrous caps and close to damaged elastic laminae, with associated medial smooth muscle cell depletion. During in vitro experiments, MGCs demonstrated a 6-fold increase in elastolytic activity when compared with macrophages and facilitated transmigration of smooth muscle cells through a collagen-elastin matrix. An elastin-derived hexapeptide (Val-Gly-Val-Ala-Pro-Gly [VGVAPG]) significantly increased the rate of macrophage fusion, providing a possible mechanism of in vivo MGC formation. Comparable to the mouse model, human specimens from carotid arteries and aortic aneurysms contained cathepsin K-positive MGCs.

CONCLUSIONS

Apolipoprotein E-/- mice fed a Paigen diet provide a model to analyze the tissue-destructive role of MGCs in vascular diseases.

Neurologic presentations of systemic vasculitides

Vasculitis or angiitis refers to a group of inflammatory disorders of the blood vessels that cause structural damage to the affected vessel, including thickening and weakening of the vessel wall, narrowing of its lumen, and, usually, vascular necrosis. Systemic vasculitis is classified according to the vessel size and histopathologic and clinical features. Vasculitides with small vessel involvement typically include Henoch-Schönlein purpura and cryoglobulinemia. Polyarteritis nodosa and Wegener granulomatosis are small- and medium-sized vessel vasculitides, whereas temporal arteritis and Takayasu arteritis involve large vessels. In this article, the authors provide a review of the neurologic presentations of the major systemic vasculitides.

Isolated superficial temporal artery dissection masquerading as giant cell arteritis

A 79-year-old male presented with symptoms suggesting giant cell arteritis (GCA) and elevation of acute-phase reactants. Bilateral superficial temporal artery (STA) biopsies were negative for GCA. However, the right-sided biopsy showed a STA dissection. Spontaneous isolated STA dissection has never been reported previously. The pertinent available literature is also discussed.

The clinical utility of high resolution magnetic resonance imaging in the diagnosis of giant cell arteritis: a critically appraised topic

BACKGROUND

Giant cell arteritis (GCA) is a relatively common form of systemic vasculitis, known for its predisposition to affect extracranial branches of the carotid artery and associated potential for causing visual loss and stroke. Neurologists need to be vigilant for this disorder, diagnose it early, and institute effective corticosteroid therapy. The differential diagnosis can be broad. Unfortunately, all clinical and laboratory features of GCA are limited by either low sensitivity or low specificity. Temporal artery biopsy remains the gold standard, but it has its own limitations. Noninvasive imaging techniques, like magnetic resonance imaging (MRI), may be capable of detecting the occurrence of GCA.

OBJECTIVE

How useful is high resolution MRI as a diagnostic test in establishing the diagnosis of GCA?

METHODS

We addressed the question through development of a structured critically appraised topic. Participants included consultant and resident neurologists, clinical epidemiologists, medical librarian, and clinical content experts in the field of neuroradiology, rheumatology, and vascular neurology. Participants started with a clinical scenario and a structured question, devised search strategies, located and compiled the best evidence, performed critical appraisals, synthesized the results, summarized the evidence, provided commentary, and declared bottom-line conclusions.

RESULTS

A single study which assessed the diagnostic value of MRI against a reference standard in GCA was appraised. For the MRI, the estimated sensitivity was 81% (95% CI 67-95), specificity was 97% (91-100), positive likelihood ratio (LR) was 26.6 (95% CI 3.8-184.8), negative LR was 0.20 (95% CI 0.10-0.41). The study exhibited several methodological weaknesses which interfered with its validity.

CONCLUSIONS

The specificity and positive LR of high resolution MRI are sufficiently high that a positive MRI combined with other clinical and laboratory data consistent with GCA may be useful in diagnosing GCA. Given the relatively low sensitivity of the test, a negative MRI would not be sufficient to rule out the diagnosis of GCA.

Giant cell arteritis: an updated review

Giant cell arteritis (GCA) is the most common primary vasculitis of adults. The incidence of this disease is practically nil in the population under the age of 50 years, then rises dramatically with each passing decade. The median age of onset of the disease is about 75 years. As the ageing population expands, it is increasingly important for ophthalmologists to be familiar with GCA and its various manifestations, ophthalmic and non-ophthalmic. A heightened awareness of this condition can avoid delays in diagnosis and treatment. It is well known that prompt initiation of steroids remains the most effective means for preventing potentially devastating ischaemic complications. This review summarizes the current concepts regarding the immunopathogenetic pathways that lead to arteritis and the major phenotypic subtypes of GCA with emphasis on large vessel vasculitis, novel modalities for disease detection and investigative trials using alternative, non-steroid therapies.