Ana García-Martínez

Large vessel involvement in biopsy-proven giant cell arteritis: prospective study in 40 newly diagnosed patients using CT angiography

Background Necroscopic and surgical studies have suggested that giant cell arteritis (GCA) may target the aorta and its main branches. Imaging techniques are able to detect large vessel vasculitis (LVV) non-invasively in patients, but the prevalence of LVV in GCA has not been clearly established. Objective To assess prospectively the prevalence, characteristics and topography of LVV in patients with newly diagnosed GCA and to determine the associated clinical and laboratory features. Methods CT angiography (CTA) was performed in 40 consecutive patients with newly diagnosed biopsy-proven GCA. Patients were treatment-naïve or had been treated with corticosteroids for <3 days. Vessel wall thickness and vessel diameter (dilation or stenoses) at four aortic segments (ascending aorta, aortic arch, descending thoracic and abdominal aorta) and at the main aortic branches were evaluated. Results LVV was detected in 27 patients (67.5%). The vessels involved were as follows: aorta (26 patients, 65%), brachiocephalic trunk (19 patients, 47.5%), carotid arteries (14 patients, 35%), subclavian arteries (17 patients, 42.5%), axillary arteries (7 patients, 17.5%), splanchnic arteries (9 patients, 22.5%), renal arteries (3 patients, 7.5%), iliac arteries (6 patients, 15%) and femoral arteries (11 patients, 30%). Dilation of the thoracic aorta was already present in 6 patients (15%). Cranial ischaemic events were significantly less frequent in patients with LVV (p=0.029). Treatment-naïve patients had a higher frequency of LVV (77% vs 29%, p=0.005). Conclusions CTA-defined LVV occurs in two-thirds of patients with GCA at the time of diagnosis and aortic dilation is already present in 15%. Previous corticosteroid treatment may decrease CTA-detected LVV.

Elevated Production of Interleukin-6 Is Associated With a Lower Incidence of Disease-Related Ischemic Events in Patients With Giant-Cell Arteritis. Angiogenic Activity of Interleukin-6 as a Potential Protective Mechanism

Background—Patients with giant-cell arteritis (GCA) who develop a strong acute-phase response are at low risk of disease-related ischemic events. Methods and Results—To assess the potential protective role of proinflammatory cytokines in the development of ischemic events in GCA, we measured tissue expression (66 individuals) and/or circulating levels (80 individuals) of interleukin (IL)-1&bgr;, tumor necrosis factor-&agr; (TNF-&agr;), and IL-6 in patients with biopsy-proven GCA. Tissue expression was determined by quantitative real-time polymerase chain reaction and immunohistochemistry. Circulating cytokines were determined by enzyme-linked immunoassay. We found that patients with disease-related ischemic events had lower IL-6 mRNA levels (5.9±2.1 versus 27.6±7.8 relative units, P =0.013), lower IL-6 immunohistochemical expression scores (1.5±0.9 versus 2.7±1, P =0.001), and lower circulating levels of IL-6 (13.6±2.1 versus 24±2.4 pg/mL, P =0.002) than patients without ischemic complications. No significant differences were found for either IL-1&bgr; or TNF-&agr;. We subsequently investigated direct effects of IL-6 on vessel wall components. We found that IL-6 stimulates endothelial cell proliferation and differentiation into capillary-like structures and induces full angiogenic activity in both ex vivo (aortic ring) and in vivo (chick chorioallantoic membrane) assays. Conclusions—GCA patients with ischemic complications have lower tissue expression and circulating levels of IL-6 than patients with no ischemic events. IL-6 has relevant direct effects on vascular wall components that might be protective: IL-6 activates a functional program related to angiogenesis that may compensate for ischemia in patients with GCA.

Development of aortic aneurysm/dilatation during the followup of patients with giant cell arteritis: A cross‐sectional screening of fifty‐four prospectively followed patients

OBJECTIVE Giant cell arteritis (GCA) may involve the aorta. Retrospective studies have demonstrated a higher prevalence of aortic aneurysm among patients with GCA compared with the general population. We investigated the prevalence of aortic aneurysm in a cohort of patients with biopsy-proven GCA using a defined protocol and assessed whether persisting low-grade disease activity is associated with higher risk of developing aortic aneurysm. METHODS Fifty-four patients with GCA (14 men and 40 women) were cross-sectionally evaluated after a median followup of 5.4 years (range 4.0-10.5 years). The screening protocol included a chest radiograph, abdominal ultrasonography scan, and computed tomography scan when aortic aneurysm was suspected or changes with respect to the baseline chest radiograph were observed. Clinical and laboratory data, corticosteroid requirements, and relapses were prospectively recorded. RESULTS Twelve patients (22.2%) had significant aortic structural damage (aneurysm/dilatation), 5 of them candidates for surgical repair. Aortic aneurysm/dilatation was more frequent among men (50%) than women (12.5%; relative risk 3.5, 95% confidence interval 1.53-8.01, P = 0.007). At the time of screening, patients with aneurysm/dilatation had lower serum acute-phase reactants, lower relapse rate, and needed shorter periods to withdraw prednisone than patients without aortic structural damage. CONCLUSION There is a substantial risk of developing aortic aneurysm/dilatation among patients with GCA. Our data do not support that aneurysm formation mainly results from persistent detectable disease activity. Additional factors including characteristics of the initial injury or the target tissue may also determine susceptibility to aortic aneurysm/dilatation.

Positron emission tomography assessment of large vessel inflammation in patients with newly diagnosed, biopsy-proven giant cell arteritis: a prospective, case–control study

Background Positron emission tomography (PET) scan is emerging as a promising imaging technique to detect large-vessel inflammation in giant cell arteritis (GCA). However, the lack of a standardised definition of arteritis based on 18fluorodeoxyglucose (FDG) uptake is an important limitation to the use of PET scan for diagnostic purposes. Objective To prospectively assess the intensity and distribution of FDG uptake at different vascular territories in patients with newly diagnosed GCA compared with controls. Methods 32 consecutive, biopsy-proven, GCA patients treated with glucocorticoids for ≤3 days were included. The control group consisted of 20 individuals, who underwent PET/CT for cancer staging. Maximal standardised uptake value (SUVm) was calculated at four aortic segments, supraaortic branches and iliac-femoral territory. Sensitivity and specificity was calculated by receiver–operator characteristic curves (ROC) analysis. Results Mean SUVm was significantly higher in patients than in controls in all vessels explored and correlated with acute-phase reactants and serum IL-6. Mean of the SUVm at all the vascular territories had an area under the curve (AUC) of 0.830, and a cut-off of 1.89 yielded a sensitivity of 80% and a specificity of 79% for GCA diagnosis. There were no significant differences in AUC among the vascular beds examined. Conclusions FDG uptake by large vessels has a substantial sensitivity and specificity for GCA diagnosis.

Small‐vessel vasculitis surrounding a spared temporal artery: Clinical and pathologic findings in a series of twenty‐eight patients

OBJECTIVE Occasionally, a temporal artery biopsy reveals small-vessel vasculitis (SVV) surrounding a spared temporal artery, the significance of which is unclear. We analyzed the final diagnosis in a series of patients with this condition and tried to identify histopathologic features with potential usefulness in predicting the ultimate diagnosis. METHODS We performed a clinical and histopathologic review of 28 patients in whom SVV surrounding a spared temporal artery was the first histologic finding that led to the diagnosis of vasculitis. For comparison purposes, we analyzed the pattern of small vessel involvement in 30 patients with biopsy-proven giant cell arteritis (GCA). RESULTS GCA was considered the most likely diagnosis in 12 patients, based on the absence of clinical evidence of additional organ involvement and normal findings on muscle biopsy and electrophysiologic study. Three patients had systemic necrotizing vasculitis (SNV), based on the demonstration of typical lesions on subsequent muscle, nerve, or kidney biopsy. After extensive evaluation, 4 patients remained unclassifiable. Nine patients were incompletely studied. Fibrinoid necrosis was significantly more frequent in patients with SNV (P = 0.0022), whereas involvement of vasa vasorum was more frequent in patients classified as having GCA (P = 0.022). No differences in the pattern of small vessel involvement were found in patients with SVV surrounding a spared temporal artery who were classified as having GCA compared with patients with biopsy-proven GCA. Granulocytes were observed at similar frequency in all conditions. CONCLUSION SVV may be the only abnormal feature in a temporal artery biopsy and the only histologic evidence of vasculitis. The diagnosis of GCA can be reasonably established in most of these patients when there is no apparent evidence of additional organ involvement. However, when fibrinoid necrosis is observed or the temporal artery vasa vasorum are not involved, SNV must be extensively excluded.

Gelatinase expression and proteolytic activity in giant-cell arteritis

Objectives: Gelatinases (MMP2 and MMP9) are expressed in giant-cell arteritis (GCA) and are thought to play a role in vessel disruption. However, their activation status and enzymatic activity have not been evaluated. Our aim was to investigate the distribution and proteolytic activity of gelatinases in GCA lesions at different stages. Methods: Expression of MMP2, MMP9, MMP2-activator MMP14 and their natural inhibitors TIMP1 and TIMP2 was determined by real-time PCR and immunohistochemistry in temporal artery sections from 46 patients and 12 controls. MMP activation status and enzymatic activity were assessed by gelatin and film in situ zymography. Results: Vascular smooth muscle cells from normal specimens constitutively expressed pro-MMP2 and its inhibitor TIMP2 with no resulting proteolytic activity. In GCA MMP2, MMP9 and MMP14 were strongly expressed in their active form by infiltrating leucocytes. Inflamed arteries also expressed TIMP1 and TIMP2. However, the MMP9/TIMP1 and MMP2/TIMP2 ratios were higher in patients compared with controls, indicating an increased proteolytic balance in GCA which was confirmed by in situ zymography. Maximal gelatinase expression and activity occurred at the granulomatous areas surrounding the internal elastic lamina (IEL). Myointimal cells also expressed MMPs and exhibited proteolytic activity, suggesting a role for gelatinases in vascular remodelling and repair. Conclusions: GCA lesions show intense expression of gelatinases. Activators and inhibitors are regulated to yield enhanced gelatinase activation and proteolytic activity. Distribution of expression and proteolytic activity suggests that gelatinases have a major role not only in the progression of inflammatory infiltrates and vessel destruction but also in vessel repair.

Tissue and serum markers of inflammation during the follow-up of patients with giant-cell arteritis—a prospective longitudinal study

Objective. To evaluate the association between inflammatory markers and relapse in GCA patients longitudinally assessed in a clinical trial of infliximab and glucocorticosteroids. Methods. Forty-four newly diagnosed GCA patients in glucocorticosteroid-induced remission were randomized to receive infliximab 5 mg/kg or placebo plus daily glucocorticosteroids, tapered using a standardized schedule. Sera were analysed for inflammatory markers at multiple, pre-defined time points. Temporal artery biopsies were performed in four patients before and after treatment to analyse changes in inflammatory and vascular remodelling marker expression. Results. Thirteen of 44 patients relapsed. Similar proportions of relapsed patients were present in both treatment arms. ESR, CRP, intercellular adhesion molecule (ICAM)-1, TNF-α, and IL-12p40 were significantly elevated near relapse. In post-treatment biopsies, mRNA expression of pro-inflammatory cytokines decreased, while vascular remodelling factors increased relative to baseline biopsies. Tissue IL-12p40 and IFN-γ mRNA remained elevated in relapsing vs remitting patients. Conclusion. Despite prior findings of high concentrations of TNF-α in temporal artery biopsies of GCA patients, infliximab plus glucocorticosteroids did not result in improved clinical outcomes. Increased measures of this biomarker did not provide useful insight into the relative importance of TNF-α in the pathogenesis of GCA. Gene expression analysis in paired temporal artery biopsies pre- and post-treatment revealed decreased inflammatory activity and active vascular remodelling following treatment. In relapsing patients, increased expression of IFN-γ and IL-12p40 in post-treatment biopsies suggests a role in sustaining disease and setting the stage for relapse during treatment withdrawal. Trial registration. ClinicalTrials.gov; http://www.clinicaltrials.gov; NCT00076726.

Clinical relevance of persistently elevated circulating cytokines (tumor necrosis factor α and interleukin‐6) in the long‐term followup of patients with giant cell arteritis

To assess the clinical relevance of increased circulating cytokines in patients with giant cell arteritis (GCA) after long‐term followup.

Prospective long term follow-up of a cohort of patients with giant cell arteritis screened for aortic structural damage (aneurysm or dilatation)

Background Aortic structural damage (ASD) may complicate the course of patients with giant cell arteritis (GCA). However the frequency and outcome of ASD has not been assessed in long term prospective studies. Methods In a previous screening of 54 biopsy proven GCA patients, significant ASD was detected in 12 (22.2%) after a median follow-up of 5.4 years. These patients were periodically evaluated (every 4 years) over a median of 10.3 years (range 4–16.6 years) in order to investigate the development of new ASD and the outcome of previously detected abnormalities. Results 18 of the 54 patients abandoned the study due to death or other reasons. The remaining 36 patients were subjected to a second screening and 14 to a third screening. 12 (33.3%) of the 36 patients re-screened and 16 (29.6%) of the initial cohort developed ASD, all but one in the thoracic aorta. Aortic diameters at the ascending and descending aorta significantly increased over time. One patient (1.9% of the initial cohort) died from aortic dissection. Surgery was advised in eight (50%) patients with ASD but could only be performed in three patients (37.7%). The development of ASD was not associated with persistence of detectable disease activity. Conclusions The incidence of ASD is maximal within the first 5 years after diagnosis but continues developing over time, affecting up to 33.3% of individuals after long term follow-up. Once ASD occurs, dilatation increases over time, underlining the need for periodic evaluation. Surgical repair is feasible in about one-third of candidates.

Increased IL-17A expression in temporal artery lesions is a predictor of sustained response to glucocorticoid treatment in patients with giant-cell arteritis

Background Interleukin 17A (IL-17A) exerts pivotal proinflammatory functions in chronic inflammatory and autoimmune diseases. Objective To investigate IL-17A expression in temporal artery lesions from patients with giant-cell arteritis (GCA), and its relationship with disease outcome. Methods Fifty-seven patients with biopsy-proven GCA were prospectively evaluated, treated and followed for 4.5 years (52–464 weeks). Relapses, time (weeks) required to achieve a maintenance prednisone dose <10 mg/day, and time (weeks) to complete prednisone withdrawal were prospectively recorded. IL-17A mRNA was measured by real-time quantitative RT-PCR in temporal arteries from all patients and 19 controls. IL-17 protein expression was assessed by immunohistochemistry/immunofluorescence. Results IL-17A expression was significantly increased in temporal artery samples from GCA patients compared with controls (6.22±8.61 vs 2.50±3.9 relative units, p=0.016). Surprisingly, patients with strong IL-17A expression tended to experience less relapses, and required significantly shorter treatment periods (median 25 vs 44 weeks to achieve <10 mg prednisone/day, p=0.0079). There was no correlation between IL-17A and RORc or RORα expression suggesting that these transcription factors may not exclusively reflect Th17 differentiation, and that cells other than Th17 cells might contribute to IL-17 expression in active patients. Accordingly, FoxP3+IL-17A+ cells were identified in lesions by confocal microscopy and were dramatically reduced in specimens from treated patients. Conclusions IL-17A expression is increased in GCA lesions, and is a predictor of response to glucocorticoid treatment. The contribution of FoxP3+ cells to IL-17A production in untreated patients suggests that induced-Tregs may facilitate disease remission when proinflammatory cytokine production is downregulated by glucocorticosteroids.