Is vascular endothelial growth factor a useful biomarker in giant cell arteritis?

Takayasu's arteritis after a prolonged course of hypertrophic osteoarthropathy

A 71-year-old male with hypertrophic osteoarthropathy was referred to our hospital because of a nocturnal fever and tenderness stretching from the left parotid region to the left front neck, in which antibacterials were ineffective. He was diagnosed with Takayasu's arteritis following findings of contrast-enhanced computed tomography and neck ultrasound. This is the first report to describe the development of Takayasu's arteritis after a prolonged course of typical hypertrophic osteoarthropathy, and the proposed hypertrophic osteoarthropathy and Takayasu's arteritis have common underlying pathophysiological factors.

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.

Novel PET Imaging of Inflammatory Targets and Cells for the Diagnosis and Monitoring of Giant Cell Arteritis and Polymyalgia Rheumatica

Giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) are two interrelated inflammatory diseases affecting patients above 50 years of age. Patients with GCA suffer from granulomatous inflammation of medium- to large-sized arteries. This inflammation can lead to severe ischemic complications (e.g., irreversible vision loss and stroke) and aneurysm-related complications (such as aortic dissection). On the other hand, patients suffering from PMR present with proximal stiffness and pain due to inflammation of the shoulder and pelvic girdles. PMR is observed in 40-60% of patients with GCA, while up to 21% of patients suffering from PMR are also affected by GCA. Due to the risk of ischemic complications, GCA has to be promptly treated upon clinical suspicion. The treatment of both GCA and PMR still heavily relies on glucocorticoids (GCs), although novel targeted therapies are emerging. Imaging has a central position in the diagnosis of GCA and PMR. While [18F]fluorodeoxyglucose (FDG)-positron emission tomography (PET) has proven to be a valuable tool for diagnosis of GCA and PMR, it possesses major drawbacks such as unspecific uptake in cells with high glucose metabolism, high background activity in several non-target organs and a decrease of diagnostic accuracy already after a short course of GC treatment. In recent years, our understanding of the immunopathogenesis of GCA and, to some extent, PMR has advanced. In this review, we summarize the current knowledge on the cellular heterogeneity in the immunopathology of GCA/PMR and discuss how recent advances in specific tissue infiltrating leukocyte and stromal cell profiles may be exploited as a source of novel targets for imaging. Finally, we discuss prospective novel PET radiotracers that may be useful for the diagnosis and treatment monitoring in GCA and PMR.

Rho Kinase Expression in Giant Cell Arteritis: Validating pERM Intensity Score to Increase Sensitivity of Temporal Artery Biopsy

Objective

Aberrant rho-kinase (ROCK) activity is implicated in several vascular and immunologic disorders. We previously demonstrated increased ROCK activity in histopathologically negative temporal artery biopsies (TAB) in subjects with clinical Giant Cell Arteritis (GCA) compared to those without GCA. This current study aimed to examine ROCK activity in a larger cohort of biopsy-negative GCA subjects and to validate the prior findings.

Methods

Subjects were categorized into 2 groups based on clinical data 6-months after TAB: biopsy-negative GCA and controls without GCA. Paraffin-embedded TAB were stained for phosphorylated ezrin/radixin/moesin (pERM), a surrogate of ROCK activity, and scored by two pathologists blinded to clinical diagnosis using a previously derived scoring system measuring staining intensity in three areas of the vessel

Results

36 subjects with biopsy-negative GCA and 43 controls were analyzed. The mean pERM intensity score in non-GCA subjects was 3.9 – 1.4 (compared to 5.0 – 1.4 in those with GCA, p = 0.002). Using the predetermined cut-off of 4 to define high pERM intensity, subjects with GCA were significantly more likely to have a high pERM intensity score compared to non-GCA, OR 3.67, 95%CI :1.19,11.36; p= 0.019. The sensitivity of high pERM intensity score for diagnosis of GCA in histologically negative TAB was 86%, 95%CI: 70,95.

Conclusion

In this well-characterized cohort, those with biopsy-negative GCA had significantly higher pERM intensity scores compared to subjects without GCA. pERM staining has diagnostic significance in enhancing the sensitivity of TAB, and may help to define the clinically important group of biopsynegative GCA.

Interleukin-1 pathway in active large vessel vasculitis patients with a poor prognosis: a longitudinal transcriptome analysis

Objectives

Large vessel vasculitis (LVV) is characterised by a high relapse rate. Because accurate assessment of the LVV disease status can be difficult, an accurate prognostic marker for initial risk stratification is required. We conducted a comprehensive longitudinal investigation of next‐generation RNA‐sequencing data for patients with LVV to explore useful biomarkers associated with clinical characteristics.

Methods

Key molecular pathways relevant to LVV pathogenesis were identified by examining the whole blood RNA from patients with LVV and healthy controls (HCs). The data were examined by pathway analysis and weighted gene correlation network analysis (WGCNA) to identify functional gene sets that were differentially expressed between LVV patients and HCs, and associated with clinical features. We then compared the expression of the selected genes during week 0, week 6, remission and relapse.

Results

The whole‐transcriptome gene expression data for 108 samples obtained from LVV patients (n = 27) and HCs (n = 12) were compared. The pathway analysis and WGCNA revealed that molecular pathway related to interleukin (IL)‐1 was significantly upregulated in LVV patients compared with HCs, which correlated with the positron emission tomography vascular activity score, a disease‐extent score based on the distribution of affected arteries. Further analysis revealed that the expression levels of genes in the IL‐1 signalling pathway remained high after conventional treatment and were associated with disease relapse.

Conclusion

Upregulation of the IL‐1 signalling pathway was a characteristic of LVV patients and was associated with the extent of disease and a poor prognosis.

Limited utility of novel serological biomarkers in patients newly suspected of having giant cell arteritis

AIM

Diagnosing and monitoring vascular activity in giant cell arteritis (GCA) is difficult due to the paucity of specific serological biomarkers. We assessed the utility of 8 novel biomarkers in an inception cohort of newly suspected GCA patients.

METHOD

Consecutive patients were enrolled between May 2016 and December 2017. Serum was collected within 72 hours of commencing corticosteroids and at 6 months. It was analyzed for levels of intra-cellular adhesion molecule 1, vascular endothelial growth factor (VEGF), pentraxin 3, von Willebrand factor and procalcitonin (5-plex R&D Systems multiplex assay) and interleukin (IL)6, IL12 and interferon-γ (high-sensitivity 3-plex ProcartaPlex multiplex assay). A GCA specific positron emission tomography / computed tomography (PET/CT) scan was performed at enrolment with uptake in each vascular territory graded and summed to derive a total vascular score (TVS).

RESULTS

For the 63 patients enrolled, 12 (19%) had a final diagnosis of biopsy-positive GCA and a further 9 had a clinical diagnosis of biopsy-negative GCA. None of the 8 biomarkers was significantly higher in GCA patients compared with those with alternative diagnoses, or demonstrated a positive correlation with the PET/CT TVS. This was in contrast to the C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) which were higher in the biopsy-positive GCA cohort (P < .04) and showed weak positive correlations with the TVS (correlation coefficient 0.34, P < .01). Procalcitonin did not distinguish between GCA and infection. Concentrations of CRP, ESR, VEGF and pentraxin 3 decreased between diagnosis and 6 months in GCA patients.

CONCLUSION

This study did not identify new serological biomarkers to assist in diagnosing or assessing the vasculitis burden in GCA.

High expression of pro-inflammatory cytokine genes IL-1β and IL-1R2 upon TLR4 activation in Takayasu arteritis

Toll-like receptors (TLR) 4 and its endogenous ligands are highly expressed in aorta. In the present study, we have explored the effect of TLR-4 activation by pro-inflammatory and angiogenic factors in PBMCs of patients with Takayasu Arteritis (TA). In the screening cohort, PBMCs of TA (n = 6) and healthy controls (n = 6) were stimulated with LPS and cultured. mRNA expression of 84 genes were quantitated by RT2 Profiler™ PCR Array kit in PBMCs. Validation set of additional PBMCs from TA (n = 7) and healthy controls [HC) (n = 7) were then stimulated with LPS to study expression of selected genes with delta Ct > 0.1 in the screening cohort. Significant gene expressions were correlated with Indian Takayasu arteritis activity scores (ITAS 2010). Increased expression of CCL2 was observed only in unstimulated PBMCs of patients with TA [median relative difference (RD) of 2.37] as compared to HC (RD 1.37, p < 0.03) in validation cohort, while stimulation with TLR4 ligand led to increased mRNA expression of IL-1β (RD 7.9, p < 0.028) and IL-1R2 (RD 0.08 p < 0.013) genes as compared to that of HC [RD of 5.32 for IL-1β and 0.01 for IL-1R2, respectively] in validation cohort. TLR4 activation also led to significantly higher expression of HPSE, TIMP1 and low expression of VEGFB, S1PR1, SERPINF1, ANGPLT4, ANGPT2, TIE1 and NOS3 genes in the screening cohort. But expression of VEGFB was not significant in validation cohort. The significant gene expressions, however, did not correlate with ITAS [ITAS2010 and ITAS-A (CRP)]. TLR4 activation leads to increased expression of IL-1β and IL-1R2 genes in PBMCs of patients with TA.

Mechanism and biomarkers in aortitis--a review

Aortitis can be the manifestation of an underlying infectious or noninfectious disease process. An autoimmune cause is suggested in a large proportion of noninfectious causes. Similar to other autoimmune diseases, the pathophysiology of aortitis has been investigated in detail, but the etiology remains unknown. Most cases of aortitis often go undetected for a long time and are often identified at late stages of the disease. Recent advances in imaging techniques have significantly improved the diagnosis of aortitis. However, significant challenges associated with the imaging techniques limit their use. Several routine inflammation-based markers, such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and inflammatory cytokines, are nonspecific and, therefore, have limited use in the diagnosis of aortitis. The search for more specific serum biomarkers, which can facilitate detection and progression is under progress. Several autoantibodies have been identified, but assigning their role in the pathogenesis as well as their specificity remains a challenge. The current review addresses some of these issues in detail. KEY MESSAGES: • Noninfectious aortitis is an autoimmune disease. • Several biomarkers, including cytokines and autoantibodies, are increased in aortitis. • Imaging techniques, commonly used to detect aortitis, are associated with the high cost and technical challenges. • There is a need to develop low-cost biomarker-based detection tools. • The knowledge of biomarkers in aortitis detection is discussed.

Markers of angiogenesis and macrophage products for predicting disease course and monitoring vascular inflammation in giant cell arteritis

OBJECTIVE

GCA, a systemic vasculitis, is characterized by an IL-6-dependent acute-phase response. This response is typically suppressed by treatment rendering CRP/ESR unreliable for monitoring vascular inflammation. Also, there are no accurate biomarkers predicting a non-favourable disease course. Here we investigated macrophage products and markers of angiogenesis as biomarkers for prognosis and monitoring of vascular inflammation.

METHODS

Forty-one newly diagnosed, glucocorticoid-naive GCA patients were prospectively followed for relapses and glucocorticoid requirement for a median of 30 months (range 0-71). Serum markers at baseline and during follow-up were compared with 33 age-matched healthy controls and 13 infection controls. Concentrations of IL-6, serum amyloid A, soluble CD163, calprotectin, YKL-40, VEGF, angiopoietin-1 and -2 and sTie2 were determined by ELISA/Luminex assay.

RESULTS

Serum concentrations of all markers, but not angiopoietin-1, were elevated in GCA patients at baseline when compared with healthy controls. High VEGF (P = 0.0025) and angiopoietin-1 (P = 0.0174) and low YKL-40 (P = 0.0369) levels at baseline were predictive of a short time to glucocorticoid-free remission. Elevated angiopoietin-2 levels were associated with an imminent relapse during treatment (P < 0.05). IL-6 correlated strongly with acute-phase markers and soluble CD163 but not with markers of angiogenesis, YKL-40 or calprotectin. Glucocorticoid treatment down-modulated all markers except for calprotectin and YKL-40. Tissue expression of markers in temporal arteries was confirmed.

CONCLUSION

Markers of angiogenesis at baseline and during treatment predict GCA disease course, suggesting utility in patient stratification for glucocorticoid-sparing therapy. Calprotectin and YKL-40 are candidate markers for monitoring vessel wall inflammation.

Biomarkers in vasculitis

PURPOSE OF REVIEW

Biomarkers are considered to be helpful in diagnosing, monitoring, predicting treatment response, and prognosis in clinical practice and as outcomes in clinical trials. In this article, we review the recent literature on new biomarkers and the expanding use of older ones in vasculitic conditions.

RECENT FINDINGS

In antineutrophil cytoplasmic antibody-associated vasculitis patients antineutrophil cytoplasmic antibody type may be useful as a predictor of relapse and response to rituximab. Moreover, serial measurements of proteinase-3 titer may help to predict relapse. Urinary soluble CD163 levels are promising for identifying active renal vasculitis. Imaging modalities such as positron emission tomography, computerized angiography tomography, and temporal artery ultrasound maintain their role in diagnosis and disease assessment in large vessel vasculitis. Fecal calprotectin is a useful marker of active gastrointestinal involvement in Behçet's syndrome.

SUMMARY

The publications reviewed here potentially may help to move the field of biomarkers in vasculitis management. However, more work toward understanding the underlying pathophysiology and effects of an intervention on the disease process are needed before true biomarkers can be realized. Further studies with appropriate control groups, using good definitions for disease states such as activity and remission are needed to guide our use of these markers correctly in the management of our patients.