PD-1 Deficiency in Regulatory T Cells May be Involved in the Pathogenesis of Takayasu's Arteritis.

OBJECTIVES: This study aims to investigate whether PD-1 expressions are abnormal in patients with TAK. METHODS: PD-1 expression was analyzed by flow cytometry. Serum cytokines IL-10, IL-7, IL-2, IL-15, CCL2, CCL3, and CXCL10 were detected using a cytokine cytometric bead array. Immunohistochemistry staining analysis was used to test PD-1 and programmed death-ligand 1 (PD-L1) expression in the aorta of three patients with TAK and three patients with atherosclerosis as controls. RESULTS: The mean fluorescence intensity of PD-1 in CD4+PD-1+ cells was decreased in patients with TAK and the frequency of CD4+Foxp3-PD-1+ cells among CD4+T cells was also decreased in peripheral blood relative to healthy controls (P < .05). The percentage of CD4+CD25+Foxp3+PD-1+ cells in the CD4+CD25+T cell population was lower in patients with TAK than in healthy control and was lower in active TAK group (P < .05). Comparing PD-1 and PDL-1 expression in aorta tissue showed that patients with TAK tended to have lower levels than patients with atherosclerosis, but the difference was not significant (P > .05). Patients with TAK had higher serum levels of IL-10, IL-7, CCL2, and CCL3 (P < .05). CONCLUSIONS: Abnormal expression of PD-1 in serum and aorta tissue of patients with TAK may contribute to TAK pathogenesis. KEY POINTS: PD-1 expression in both peripheral blood and aorta tissue of TAK patients decreased relative to healthy controls, indicating that PD-1 might be involved in TAK pathogenesis.

Metabolic inflammatory volume and total inflammatory glycolysis: novel parameters to evaluate PET-CT disease activity in Takayasu arteritis.

OBJECTIVES: To evaluate diagnostic accuracy for active Takayasu arteritis (TAK) for two novel 18F-fluorodeoxyglucose PET-CT parameters, the inflammatory volume (MIV) and total inflammatory glycolysis (TIG), to quantitate volume of metabolically-active arterial tissue. METHODS: From a cohort of TAK (n = 36, 35 immunosuppressive-naïve), images of PET-CTs were reviewed for mean and maximum standardized uptake value (SUVmean and SUVmax), target-to-blood pool ratio (TBR), target-to-liver ratio (TLR), and PET Vasculitis Activity Score (PETVAS). Regions of interest were drawn to semiautomatically calculate MIV in areas of 18F-fluorodeoxyglucose uptake ≥ 1.5 SUVmean after excluding physiological tracer uptake. TIG was calculated by multiplying MIV with SUVmean. PET-CT parameters, ESR, CRP, and clinical disease activity scores were compared against the gold standard of physician global assessment of disease activity (PGA, active/inactive). RESULTS: Using dichotomized cut-offs for active TAK at SUVmax (≥ 2.21), SUVmean (≥ 1.58), TBR (≥ 2.31), TLR (≥ 1.22), PETVAS (various cut-offs), ESR (≥ 40 mm/hour), and CRP (≥ 6 mg/L), the novel indices MIV (≥ 1.8) and TIG (≥ 2.7) performed similar [area under the receiver operating characteristics curve (AUC) 0.873 for both] to SUVmax (AUC 0.841) and SUVmean (AUC 0.851), and better than TBR (AUC 0.773), TLR (AUC 0.773), PETVAS [≥ 5.5 (AUC 0.750), ≥ 10 (AUC 0.636), ≥ 15 (AUC 0.546)], ESR (AUC 0.748), or CRP (AUC 0.731). MIV and TIG had similar agreement with PGA or CRP as with SUVmax or SUVmean, and better agreement than TBR, TLR, or PETVAS cut-offs. CONCLUSIONS: MIV and TIG performed similarly, therefore, are viable alternatives to existing PET-CT parameters to assess TAK disease activity in this preliminary report. Key Points • MIV and TIG performed similar to SUVmax and SUVmax for disease activity assessment in TAK. • MIV and TIG distinguished active TAK better than TBR, TLR, PETVAS cut-offs, ESR, or CRP. • MIV and TIG had better agreement with PGA or CRP than TBR, TLR, or PETVAS cut-offs.

Neutrophil extracellular trap formation in anti-neutrophil cytoplasmic antibody-associated and large-vessel vasculitis.

Levels of neutrophil extracellular traps (NETs) were measured in plasma of healthy controls (HC, n = 30) and patients with granulomatosis with polyangiitis (GPA, n = 123), microscopic polyangiitis (MPA, n = 61), Takayasu's arteritis (TAK, n = 58), and giant cell arteritis (GCA, n = 68), at times of remission or activity and correlated with levels of the platelet-derived thrombospondin-1 (TSP-1). Levels of NETs were elevated during active disease in patients with GPA (p < 0.0001), MPA (p = 0.0038), TAK (p < 0.0001), and GCA (p < 0.0001), and in remission for GPA, p < 0.0001, MPA, p = 0.005, TAK, p = 0.03, and GCA, p = 0.0009. All cohorts demonstrated impaired NET degradation. Patients with GPA (p = 0.0045) and MPA (p = 0.005) had anti-NET IgG antibodies. Patients with TAK had anti-histone antibodies (p < 0.01), correlating with presence of NETs. Levels of TSP-1 were increased in all patients with vasculitis, and associated with NET formation. NET formation is a common process in vasculitides. Targeting NET formation or degradation could be potential therapeutic approaches for vasculitides.

A novel molecular mechanism of vascular fibrosis in Takayasu arteritis: macrophage-derived GPNMB promoting adventitial fibroblast extracellular matrix production in the aorta.

Takayasu arteritis (TAK) is a chronic large vessel disease characterized by aortic fibrotic thickening, which was mainly mediated by activation of aorta adventitial fibroblasts (AAFs). Our previous genetic study demonstrated that TAK-associated locus IL6 rs2069837 regulated glycoprotein non-metastatic melanoma protein B (GPNMB) expression. Thus, this study aimed to investigate the pathogenic role of GPNMB in TAK. Through pathological staining, we find that GPNMB was mainly expressed in vascular adventitia and positively correlated with adventitial extracellular matrix (ECM) expression in TAK vascular lesion. Specifically, GPNMB was increased in adventitial CD68+ macrophages, which were closely located with CD90+ adventitial fibroblasts. In in-vitro cell culture, THP-1-derived macrophages with GPNMB overexpression promoted ECM expression in AAFs. This effect was also confirmed in aortic tissue or AAFs culture with GPNMB overexpression or active GPNMB protein stimulation. Mechanistically, Co-IP assay and siRNA or inhibitor intervention demonstrated that integrin αVß1 receptor mediated GPNMB effect on AAFs, which also activated downstream Akt and Erk pathway in AAFs. Furthermore, we showed that leflunomide treatment inhibited GPNMB-mediated fibrosis in AAFs, as well as GPNMB expression in macrophages, which were also partially validated in leflunomide-treated patients. Taken together, these data indicated that macrophage-derived GPNMB promotes AAFs ECM expression via the integrin αVß1 receptor and Akt/Erk signaling pathway and leflunomide might play an anti-fibrotic role in TAK by interfering with the macrophage-derived GPNMB/AAFs axis. This study provides evidence that targeting GPNMB is a potential therapeutic strategy for treating vascular fibrosis in TAK.

The establishment and validation of reference intervals for plasma Pentraxin-3 in healthy volunteers and patients with Takayasu's arteritis.

BACKGROUND AND AIMS: To establish reference intervals (RIs) for PTX-3 and to validate the performance of these RIs in a population including healthy volunteers and Takayasu's arteritis (TAK) patients. MATERIALS AND METHODS: Plasma PTX-3 levels were determined in 166 healthy volunteers and 63 TAK patients. RIs were established in healthy volunteers according to guidelines from the Clinical and Laboratory Standards Institute (CLSI, C28-A3). Global assessment was used to quantitatively diagnose active/non-active TAK patients. Screening and monitoring performances were validated by identifying active TAK patients from the whole population or diagnosed TAK patients. RESULTS: The PTX-3 RI was calculated to be 0.87-2.78 ng/mL. For screening purposes, 1.55 ng/mL had a high sensitivity of 90.32 % and the RI upper limit (2.78 ng/mL) had a high specificity of 97.94 %. For monitoring purposes, the sensitivity/specificity of the cut-off value (1.55 ng/mL) and RI median were 90.32 %/90.63 % and 80.85 %/90.63 %, respectively. These screening and monitoring performances of PTX-3 were superior to those of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). CONCLUSION: The distribution of serum PTX-3 levels was stable and uniform across the population. The screening and monitoring performances of the cut-off value and RI-derived values of PTX-3 were higher than CRP and ESR.

Th17.1 lymphocytes: emerging players in the orchestra of immune-mediated inflammatory diseases.

It is now well established that Th17 lymphocytes associate with myriad immune-mediated inflammatory diseases. Over the past one and a half decades, a subset of Th17 lymphocytes viz. Th17.1 lymphocytes has been identified in pre-clinical and clinical models of inflammatory rheumatic diseases. These lymphocytes secrete IL-17A (signature cytokine of Th17 lymphocytes) as well as IFN-γ (the signature cytokine of Th1 lymphocytes). They express the chemokine markers for Th1 (CXCR3) as well as Th17 (CCR6) lymphocytes. Th17.1 lymphocytes also express the drug efflux protein p-glycoprotein, which associates with resistance to corticosteroids and other immunosuppressive drugs. This narrative review overviews the evidence regarding Th17.1 lymphocytes in different inflammatory rheumatic diseases. It is now recognized that Th17.1 lymphocytes are increased in the synovial fluid of affected joints in rheumatoid arthritis (RA) and associate with poor treatment response to abatacept. Th17.1 lymphocytes from synovial fluid of RA are less responsive to immunosuppression than those from the peripheral blood. In sarcoidosis, Th17.1 lymphocytes are concentrated in mediastinal lymph nodes and alveolar lining. Such Th17.1 lymphocytes in sarcoidosis are the predominant source of IFN-γ in the sarcoid lung. Th17.1 lymphocytes are elevated in lupus and Takayasu arteritis and associate with disease activity. Future studies should evaluate isolated Th17.1 lymphocytes from peripheral blood or sites of pathology such as synovial fluid and assess their modulation with immunosuppressive therapy in vitro. The analysis of gene expression signature of isolated Th17.1 lymphocytes might enable the identification of newer therapeutic strategies specifically targeting these cell populations in inflammatory rheumatic diseases. Key Points • Th17.1 lymphocytes are a subset of Th17 lymphocytes secreting both IFN-γ and IL-17 • Th17.1 lymphocytes drive neutrophilic inflammation, granuloma formation, and corticosteroid resistance • Th17.1 lymphocytes are elevated in rheumatoid arthritis and sarcoidosis at sites of inflammation • Increased circulating Th17.1 lymphocytes have been identified in lupus and Takayasu arteritis and associate with active disease.

Critical Role of Notch-1 in Mechanistic Target of Rapamycin Hyperactivity and Vascular Inflammation in Patients With Takayasu Arteritis.

OBJECTIVE: Takayasu arteritis (TA) is a major type of large vessel vasculitis characterized by progressive inflammation in vascular layers. In our recent study we identified a central role of mechanistic target of rapamycin (mTOR) hyperactivity in proinflammatory T cell differentiation in TA. This study was undertaken to explore potential mechanisms underpinning T cell-intrinsic mTOR hyperactivity and vascular inflammation in TA, with a focus on Notch-1. METHODS: Notch-1 expression and activity was determined according to Notch-1, activated Notch-1, and HES-1 levels. We detected mTOR activity with intracellular expression of phosphorylated ribosomal protein S6. Differentiation of proinflammatory T cells was analyzed by detecting Th1 and Th17 lineage-determining transcription factors. The function of Notch-1 was evaluated using γ-secretase inhibitor DAPT and gene knockdown using a short hairpin RNA (shRNA) strategy. We performed our translational study using humanized NSG mouse chimeras in which human vasculitis was induced using immune cells from TA patients. RESULTS: CD4+ T cells from TA patients exerted Notch-1high , leading to mTOR hyperactivity and spontaneous maldifferentiation of Th1 cells and Th17 cells. Blockade of Notch-1 using DAPT and Notch-1 shRNA efficiently abrogated mTOR complex 1 (mTORC1) activation and proinflammatory T cell differentiation. Mechanistically, Notch-1 promoted mTOR expression, interacted with mTOR, and was associated with lysosomal localization of mTOR. Accordingly, systemic administration of DAPT and CD4+ T cell-specific gene knockdown of Notch-1 could alleviate vascular inflammation in humanized TA chimeras. CONCLUSION: Expression of Notch-1 is elevated in CD4+ T cells from TA patients, resulting in mTORC1 hyperactivity and proinflammatory T cell differentiation. Targeting Notch-1 is a promising therapeutic strategy for the clinical management of TA.

FABP3 overexpression promotes vascular fibrosis in Takayasu's arteritis by enhancing fatty acid oxidation in aorta adventitial fibroblasts.

OBJECTIVE: To identify the role of fatty acid binding protein 3 (FABP3) in vascular fibrosis in Takayasu's arteritis (TAK) and to explore the underlying molecular mechanism. METHODS: The expression of FABP3 and extracellular matrix proteins (ECMs) were detected in aorta tissues from TAK patients (n = 12) and healthy controls (n = 8) by immunohistochemistry. The concentration of serum proteins was determined by ELISA. CCK8 and Ki67 staining were used to measure aorta adventitial fibroblast (AAF) proliferation. Widely targeted lipidomic profiling was used to screen for associated metabolic pathways. Changes in ECMs and fatty acid oxidation (FAO)-related enzymes were determined by RT-qPCR and Western blot. The interactions between FABP3 and these enzymes were explored with a co-immunoprecipitation (Co-IP) assay. RESULTS: The expression of FABP3 was increased in the thickened adventitia of TAK patients and was positively correlated with the serum expression of ECMs. FABP3 knockdown inhibited AAF proliferation and ECM production, whereas FABP3 overexpression enhanced these processes. Further analysis revealed that FABP3 upregulation promoted carnitine palmitoyltransferase 1A and carnitine/acylcarnitine carrier protein (CACT) expression, two key enzymes in FAO, as well as adenosine triphosphate (ATP) levels. FABP3 and CACT were co-localized in the adventitia and bound to each other in AAFs. Etomoxir reversed the enhanced FAO, ATP production, AAF proliferation and ECM production mediated by FABP3 upregulation. Treatment with 60 g/day curcumin granules for 3 months reduced the level of serum FABP3. Curcumin also inhibited vascular fibrosis by reducing FABP3-enhanced FAO in AAFs. CONCLUSION: Elevated FABP3 expression accelerated vascular fibrosis in TAK, which was likely mediated by promoting FAO in AAFs.

Mast cells drive pathologic vascular lesions in Takayasu arteritis.

BACKGROUND: Takayasu arteritis (TAK) is a large vessel vasculitis resulting in artery wall remodeling with segmental stenosis and/or aneurysm formation. Mast cells (MCs) are instrumental in bridging cell injury and inflammatory response. OBJECTIVES: This study sought to investigate the contribution of MCs on vessel permeability, angiogenesis, and fibrosis in patients with TAK. METHODS: MC activation and their tissue expression were assessed in sera and in aorta from patients with TAK and from healthy donors (HDs). In vivo permeability was assessed using a modified Miles assay. Subconfluent cultured human umbilic vein endothelial cells and fibroblasts were used in vitro to investigate the effects of MC mediators on angiogenesis and fibrogenesis. RESULTS: This study found increased levels of MC activation markers (histamine and indoleamine 2,3-dioxygenase) in sera of patients with TAK compared with in sera of HDs. Marked expression of MCs was shown in aortic lesions of patients with TAK compared with in those of noninflammatory aorta controls. Using Miles assay, this study showed that sera of patients with TAK significantly increased vascular permeability in vivo as compared with that of HDs. Vessel permeability was abrogated in MC-deficient mice. MCs stimulated by sera of patients with TAK supported neoangiogenesis (increased human umbilic vein endothelial cell proliferation and branches) and fibrosis by inducing increased production of fibronectin, type 1 collagen, and α-smooth muscle actin by fibroblasts as compared to MCs stimulated by sera of HD. CONCLUSIONS: MCs are a key regulator of vascular lesions in patients with TAK and may represent a new therapeutic target in large vessel vasculitis.

Assessment of Low Bone Mineral Density in Untreated Patients with Takayasu's Arteritis.

Chronic inflammation affects bone metabolism and accelerates bone loss. This study is aimed at analyzing the prevalence of low bone mineral density (LBMD) in patients with untreated Takayasu's arteritis (TA) and risk factors. Forty untreated TA patients were enrolled, including 38 premenopausal women and 2 men before 50 years old. The control group included 60 age- and gender-matched healthy persons. Bone mineral density (BMD) of lumbar vertebrae and hip in patients with TA and the control group was measured by the dual-energy X-ray method. Serum 25OHD and ß-CTX were also measured. The lumbar BMD of TA patients (0.89 ± 0.11 g/cm2) was significantly lower than that of the healthy control (0.97 ± 0.11 g/cm2). The prevalence of LBMD at the lumbar spine (17.50%) was significantly higher than that of the control group (3.33%). However, there was no significant difference at the hip. The 25OHD of TA patients was lower than that of healthy controls, while the level of ß-CTX was higher. The levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) in patients with LBMD were higher than those in patients with normal BMD. According to univariate correlation analysis, there was a significant negative correlation between LDL-C and lumbar BMD. Binary logistic regression analysis showed that LDL-C was an important factor affecting the occurrence of LBMD in patients with TA (OR = 25.269, P = 0.02). Our result reveals bone loss in TA patients, which hints the relationship among inflammation, lipid metabolism, and bone metabolism.

The Immunopathology of Giant Cell Arteritis Across Disease Spectra.

Giant cell arteritis (GCA) is a granulomatous systemic vasculitis of large- and medium-sized arteries that affects the elderly. In recent years, advances in diagnostic imaging have revealed a greater degree of large vessel involvement than previously recognized, distinguishing classical cranial- from large vessel (LV)- GCA. GCA often co-occurs with the poorly understood inflammatory arthritis/bursitis condition polymyalgia rheumatica (PMR) and has overlapping features with other non-infectious granulomatous vasculitides that affect the aorta, namely Takayasu Arteritis (TAK) and the more recently described clinically isolated aortitis (CIA). Here, we review the literature focused on the immunopathology of GCA on the background of the three settings in which comparisons are informative: LV and cranial variants of GCA; PMR and GCA; the three granulomatous vasculitides (GCA, TAK, and CIA). We discuss overlapping and unique features between these conditions across clinical presentation, epidemiology, imaging, and conventional histology. We propose a model of GCA where abnormally activated circulating cells, especially monocytes and CD4+ T cells, enter arteries after an unknown stimulus and cooperate to destroy it and review the evidence for how this mechanistically occurs in active disease and improves with treatment.

Specific microbiome profile in Takayasu's arteritis and giant cell arteritis.

Recent studies have provided evidence of a close link between specific microbiota and inflammatory disorders. While the vessel wall microbiota has been recently described in large vessel vasculitis (LVV) and controls, the blood microbiome in these diseases has not been previously reported (LVV). We aimed to analyse the blood microbiome profile of LVV patients (Takayasu's arteritis [TAK], giant cell arteritis [GCA]) and healthy blood donors (HD). We studied the blood samples of 13 patients with TAK (20 samples), 9 patients with GCA (11 samples) and 15 HD patients. We assessed the blood microbiome profile by sequencing the 16S rDNA blood bacterial DNA. We used linear discriminant analysis (LDA) coupled with linear discriminant effect size measurement (LEfSe) to investigate the differences in the blood microbiome profile between TAK and GCA patients. An increase in the levels of Clostridia, Cytophagia and Deltaproteobacteria and a decrease in Bacilli at the class level were found in TAK patients compared with HD patients (LDA > 2, p < 0.05). Active TAK patients had significantly lower levels of Staphylococcus compared with inactive TAK patients. Samples of GCA patients had an increased abundance of Rhodococcus and an unidentified member of the Cytophagaceae family. Microbiota of TAK compared with GCA patients was found to show higher levels of Candidatus Aquiluna and Cloacibacterium (LDA > 2; p < 0.05). Differences highlighted in the blood microbiome were also associated with a shift of bacterial predicted metabolic functions in TAK in comparison with HD. Similar results were also found in patients with active versus inactive TAK. In conclusion, patients with TAK were found to present a specific blood microbiome profile in comparison with healthy donors and GCA subjects. Significant changes in the blood microbiome profiles of TAK patients were associated with specific metabolic functions.

The relationships of serum homocysteine levels and traditional lipid indicators with disease activity and coronary artery involvement in Takayasu arteritis.

Serum homocysteine (HCY) levels have been associated with the occurrence of coronary stenosis and disease activity in large-vessel vasculitis. However, whether increases in serum HCY levels and traditional lipid indicators are associated with coronary artery involvement and disease activity in Chinese Han Takayasu arteritis (TA) patients is unknown. This study aims to investigate the clinical and laboratory features of TA by assessing their association with disease activity in TA patients, and to explore the risk factors associated with coronary artery involvement in these patients. Serum HCY levels and traditional lipid indicators were tested in one hundred ninety TA patients and one hundred fifty-four healthy controls. We analyzed the relationships of serum HCY levels and traditional lipid indicators with disease activity and analyzed the risk factors for coronary artery involvement. Twenty-one TA patients were found to have coronary artery stenosis (≥ 50%). TA patients had significantly higher levels of HCY than did healthy controls (p < 0.0001). Serum levels of HCY and low-density lipoprotein cholesterol (LDL-C); the ratios of LDL-C to high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC) to HDL-C, and triglycerides (TG) to HDL-C; and the values of atherogenic index of plasma (AIP) were significantly higher in patients with active TA than in patients with inactive TA and in TA patients with coronary artery involvement than in TA patients without coronary artery involvement. By contrast, the serum levels of HDL-C were significantly lower in patients with active TA than in patients with inactive TA and in TA patients with coronary artery involvement than in TA patients without coronary artery involvement (p < 0.05). In addition, the serum levels of TC and TG were significantly higher in TA patients with coronary artery involvement than those in TA patients without coronary artery involvement. Elevated serum HCY levels increased the risk of coronary artery involvement by 1.3-fold (p = 0.011, odds ratio [OR] = 1.275, 95% confidence interval [CI]: 1.056-1.539), and the cutoff value for serum HCY was 9.55 µmol/L. Elevated serum TG levels increased the risk of coronary artery involvement by 3.5-fold (p < 0.0001, OR = 3.534, 95% CI: 1.907-6.547), and the cutoff value for serum TG was 1.215 mmol/L. The risk of coronary artery involvement was 2.5-fold higher when an elevated TG/HDL-C ratio was present (p < 0.0001, OR = 2.513, 95% CI: 1.567-4.032). This study showed that serum HCY and TG levels and the TG/HDL-C ratio are independent risk factors for coronary artery involvement in TA patients.

Identification of two major autoantigens negatively regulating endothelial activation in Takayasu arteritis.

The presence of antiendothelial cell antibodies (AECAs) has been documented in Takayasu arteritis (TAK), a chronic granulomatous vasculitis. Here, we identify cell-surface autoantigens using an expression cloning system. A cDNA library of endothelial cells is retrovirally transfected into a rat myeloma cell line from which AECA-positive clones are sorted with flow cytometry. Four distinct AECA-positive clones are isolated, and endothelial protein C receptor (EPCR) and scavenger receptor class B type 1 (SR-BI) are identified as endothelial autoantigens. Autoantibodies against EPCR and SR-BI are detected in 34.6% and 36.5% of cases, respectively, with minimal overlap (3.8%). Autoantibodies against EPCR are also detected in ulcerative colitis, the frequent comorbidity of TAK. In mechanistic studies, EPCR and SR-BI function as negative regulators of endothelial activation. EPCR has also an effect on human T cells and impair Th17 differentiation. Autoantibodies against EPCR and SR-BI block the functions of their targets, thereby promoting pro-inflammatory phenotype.

T-614 inhibits human aortic adventitial fibroblast proliferation and promotes interleukin-8 production in vitro.

OBJECTIVES: The effect and underlying mechanism of T-614 (iguratimod) on Takayasu's arteritis (TA) are unknown. Here, we report the effects of T-614 on cell proliferation and interleukin-8 (IL-8) production in human aortic adventitial fibroblasts (HAAFs) in vitro and explore its initial benefit in terms of vascular wall inflammation and remodeling for patients with TA. METHODS: HAAFs were cultured with 0, 5, 50, 100, or 250 µg/ml T-614 in the absence or presence of tumor necrosis factor-α (TNF-α) in vitro. Cell viability was determined by a modified MTT assay. Supernatant IL-8 levels were measured by enzyme-linked immunosorbent assays. RESULTS: In the presence of TNF-α, compared to that in the control group, cell viability of HAAFs significantly decreased in the 50, 100, and 250 µg/ml T-614 treatment groups (OD value: P < 0.01, P < 0.001, P < 0.001, respectively; survival fraction (SF): P < 0.05, P < 0.001, P < 0.001, respectively). However, there was no significant difference in cell viability between TNF-α-stimulated and unstimulated groups at the same concentration of T-614. In the absence or presence of TNF-α, T-614 suppressed HAAF cell viability dose-dependently (OD value: r = -0.915, P = 0.000; r = -0.926, P = 0.000, respectively; SF: r = -0.897, P = 0.000; r = -0.885, P = 0.000, respectively). Compared to that in the control group, in the absence of TNF-α, IL-8 levels in the 5 and 100 µg/ml T-614-treated groups were significantly higher (P < 0.05); in the presence of TNF-α, IL-8 levels in the 5, 50, and 100 µg/ml T-614-treated groups were significantly higher (P < 0.001, P < 0.001, P < 0.01, respectively). Further, there was a negative correlation between supernatant IL-8 levels and T-614 concentration in groups stimulated with TNF-α (r = -0.670, P = 0.000), but there was no significant correlation between these parameters in groups that were not stimulated with TNF-α. CONCLUSIONS: In the absence or presence of TNF-α, T-614 can inhibit HAAF proliferation and promote IL-8 production in vitro; therefore, it could be used to prevent adventitial thickening of the aorta and improve vascular remodeling in inflammatory environments in vitro and might provide a new immunotherapeutic intervention for TA.

The C-Reactive Protein/Albumin Ratio and Complete Blood Count Parameters as Indicators of Disease Activity in Patients with Takayasu Arteritis.

BACKGROUND This study aimed to evaluate the ratio of C-reactive protein (CRP) to albumin, inflammatory markers, and parameters from the complete blood count (CBC) in patients with Takayasu arteritis and the association with disease activity. MATERIAL AND METHODS A retrospective study included thirty-two patients with Takayasu arteritis and 32 healthy controls. Clinical and demographic characteristics of patients with Takayasu arteritis were recorded at baseline, before medication and on remission. Similar data were obtained for the controls at recruitment. Remission was defined as more than six months of stable disease without new vascular lesions in patients who previously had active disease. Kerr's criteria were used to define active Takayasu arteritis. RESULTS In patients with Takayasu arteritis, the erythrocyte sedimentation rate (ESR), CRP, CRP/albumin ratio, red cell distribution width (RDW), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and monocyte-lymphocyte ratio (MLR) were significantly higher, and albumin and MPV were significantly lower compared with controls. The ESR, CRP, CRP/albumin ratio, NLR, PLR, and MLR were decreased in remission, whereas MPV was increased. CRP and the CRP/albumin ratio were positively correlated and albumin and MPV were negatively correlated with disease activity. The CRP/albumin ratio had the highest correlation with disease activity in Takayasu arteritis. The CRP/albumin ratio, RDW, NLR, PLR, and MLR were positively correlated with CRP and ESR. CONCLUSIONS The CRP/albumin ratio, RDW, NLR, PLR, MLR, and MPV were markers of remission of active disease, and the CRP/albumin ratio, total albumin, and MPV were markers of disease activity in Takayasu arteritis.

Cytokines, growth factors and proteases in medium and large vessel vasculitis.

Giant cell arteritis and Takayasu arteritis are autoimmune vasculitides that cause aneurysm formation and tissue infarction. Extravascular inflammation consists of an intense acute phase response. Deeper understanding of pathogenic events in the vessel wall has highlighted the loss of tissue protective mechanisms, the intrusion of immune cells into "forbidden territory", and the autonomy of self-renewing vasculitic infiltrates. Adventitial vasa vasora critically control vessel wall access and drive differentiation of tissue-invasive T cells. Selected T cells establish tissue residency and build autonomous, self-sufficient inflammatory lesions. Pathogenic effector T cells intrude and survive due to failed immune checkpoint inhibition. Vasculitis-sustaining T cells and macrophages provide a broad portfolio of effector functions, involving heterogeneous populations of pro-inflammatory T cells and diverse macrophage subsets that ultimately induce wall capillarization and intimal hyperplasia. Redirecting diagnostic and therapeutic strategies from control of extravascular inflammatory markers to suppression of vascular inflammation will improve disease management.

Autophagy promotes aortic adventitial fibrosis via the IL-6/Jak1 signaling pathway in Takayasu's arteritis.

BACKGROUND: Autophagy is a ubiquitous and evolutionarily conserved self-rescue process. Studies have shown that autophagy is involved in the pathogenesis of multiple diseases; however, whether autophagy is associated with the pathogenesis of Takayasu's arteritis (TA), a large vessel idiopathic inflammatory disease characterized by vascular fibrosis, remains unclear. Moreover, although IL-6 is believed to be a direct target for TA treatment, anti-IL-6 treatment could not block TA-associated fibrosis in some cases, which impairs the aortic function of patients and can result in death. Thus, identify the mechanisms associated with TA is extremely important. Based on the relationship between autophagy and IL-6, we investigated the role of autophagy in the vascular fibrosis of TA induced by IL-6. METHODS: Autophagy proteins (LC3 and Atg3), IL-6, and markers of fibrosis (collagen 1 and α-SMA) were detected in tissues with TA lesions via immunochemistry, immunofluorescence, and Western blot, respectively. Different stages of autophagy were analyzed by the specific inhibitors, 3-methyladenosine (early stage), hydroxychloroquine sulfate (late stage), and bafilomycin A1 (late stage). Autophagosomes were detected using electron microscopy and a viral-vector transfection assay. The fibrosis profiles induced by IL-6-dependent autophagy was assessed with an ELISA. RESULTS: The expression of autophagy, IL-6, and fibrosis markers were elevated and correlated with each other in the adventitia tissues of TA patients. Furthermore, exogenous IL-6/IL-6Rα could significantly increase autophagy and fibrosis in vitro. An autophagy inhibitor was found to significantly block both autophagy and fibrosis induced by IL-6. Finally, IL-6 was found to significantly promote autophagy-induced fibrosis through the activation of the Jak1 pathway. CONCLUSIONS: IL-6-induced autophagy plays an important role in vascular fibrosis of TA. Targeting autophagy pathways might represent a novel therapeutic option for the treatment of TA.

Novel Biomarkers for the Precisive Diagnosis and Activity Classification of Takayasu Arteritis.

BACKGROUND: Establishing the diagnosis and determining disease activity of Takayasu arteritis (TA) remains challenging. Novel biomarkers might help to solve this problem. METHODS: In the screening phase, by using large-scale protein arrays detecting samples from 90 subjects (TA active, 29; TA inactive 31; and controls, 30). In the validation phase, by using enzyme-linked immunosorbent assay (ELISA), potential biomarkers for TA diagnosis, and activity classification were measured in independent cohorts, respectively. RESULTS: In the screening phase, 18 cytokines significantly differentially enriched between TA patients and controls and another 15 cytokines significantly differentially enriched between TA patient in active and inactive status were identified (adjusted P<0.05). In the validation phase, TIMP (tissue inhibitor of metalloproteinases)-1 was identified as a specific biomarker for TA diagnosis that a cutoff value of 221.86 µg/L could provide a specificity of 89.58% and a positive predictive value of 0.92. Meanwhile, we found it unreliable to use a single biomarker for TA activity classification. Considering this, we further built a logistic regression model based on multiple cytokines, including CA (cancer antigen) 125, FLRG (follistatin-related protein), IGFBP (insulin-like growth factor-binding protein)-2, CA15-3, GROa (growth-regulated alpha protein), LYVE (lymphatic vessel endothelial hyaluronic acid receptor)-1, ULBP (UL16-binding protein)-2, and CD (cluster of differentiation) 99, with an area under the curve reaching 0.909 for discriminating TA activity status. CONCLUSIONS: This study suggested TIMP-1 as a specific biomarker for TA diagnosis with a cutoff value of 221.86 µg/L. Furthermore, we provided a logistic regression model based on 8 biomarkers for the precisive activity classification of TA with an area under the curve of 0.909.

Microparticles from Endothelial Cells and Immune Cells in Patients with Takayasu Arteritis.

AIM: This study was designed to analyze microparticles (MPs) from endothelial cells (EMPs) and immune cells from healthy individuals and paitents with Takayasu arteritis (TA), and any possible relationships between MPs and TA acitivity. METHODS: MPs derived from the plasma of 51 subjects were analyzed, including 32 patients with TA and 19 healthy individuals. Flow cytometry was performed with Annexin (Anx)-V and antibodies against surface markers of endothelial cells (CD144), T cells (CD3), B cells (CD19), and monocytes (CD14). RESULTS: The concentrations of total EMPs, AnxV＋ EMPs and AnxV- EMPs were significantly increased when comparing patients with TA and healthy controls (54×103 vs. 32×103 MPs /ml, P=0.0004; 22×103 vs. 12×103 MPs /ml, P=0.0006; and 31×103 vs. 19×103 MPs /ml, P=0.0005), and comparing active TA patients with remission ones (85×103 vs. 45×103 MPs /ml, P=0.016; 39×103 vs. 14×103 MPs /ml, P=0.0092; and 47×103 vs.29×103 MPs /ml, P=0.0371). In addition, the concentrations of total EMPs (odds ratio [OR]=1.024, 95% confidence interval [CI]: 1.001 to 1.048, P=0.037), AnxV＋(OR=1.089, 95%CI: 1.011 to 1.172, P=0.024), and AnxV- EMPs (OR=1.029, 95% CI: 1.002 to 1.056, P=0.034) were positively related to TA activity. With multiple linear regression analysis, platelet was associated with both total and AnxV- EMP concentrations independently, while erythrocyte sedimentation rate was independently correlated with AnxV＋EMPs. CONCLUSION: Concentrations of endothelial microparticles are correlated with inflammation in Takayasu arteritis and may be useful markers to assess disease activity.