Curry L. Koening

Hepcidin mediates transcriptional changes that modulate acute cytokine-induced inflammatory responses in mice

Hepcidin is a peptide hormone that regulates iron homeostasis and acts as an antimicrobial peptide. It is expressed and secreted by a variety of cell types in response to iron loading and inflammation. Hepcidin mediates iron homeostasis by binding to the iron exporter ferroportin, inducing its internalization and degradation via activation of the protein kinase Jak2 and the subsequent phosphorylation of ferroportin. Here we have shown that hepcidin-activated Jak2 also phosphorylates the transcription factor Stat3, resulting in a transcriptional response. Hepcidin treatment of ferroportin-expressing mouse macrophages showed changes in mRNA expression levels of a wide variety of genes. The changes in transcript levels for half of these genes were a direct effect of hepcidin, as shown by cycloheximide insensitivity, and dependent on the presence of Stat3. Hepcidin-mediated transcriptional changes modulated LPS-induced transcription in both cultured macrophages and in vivo mouse models, as demonstrated by suppression of IL-6 and TNF-alpha transcript and secreted protein. Hepcidin-mediated transcription in mice also suppressed toxicity and morbidity due to single doses of LPS, poly(I:C), and turpentine, which is used to model chronic inflammatory disease. Most notably, we demonstrated that hepcidin pretreatment protected mice from a lethal dose of LPS and that hepcidin-knockout mice could be rescued from LPS toxicity by injection of hepcidin. The results of our study suggest a new function for hepcidin in modulating acute inflammatory responses.

Identification of multiple genetic susceptibility loci in Takayasu arteritis

Takayasu arteritis is a rare inflammatory disease of large arteries. The etiology of Takayasu arteritis remains poorly understood, but genetic contribution to the disease pathogenesis is supported by the genetic association with HLA-B*52. We genotyped ~200,000 genetic variants in two ethnically divergent Takayasu arteritis cohorts from Turkey and North America by using a custom-designed genotyping platform (Immunochip). Additional genetic variants and the classical HLA alleles were imputed and analyzed. We identified and confirmed two independent susceptibility loci within the HLA region (r(2) < 0.2): HLA-B/MICA (rs12524487, OR = 3.29, p = 5.57 × 10(-16)) and HLA-DQB1/HLA-DRB1 (rs113452171, OR = 2.34, p = 3.74 × 10(-9); and rs189754752, OR = 2.47, p = 4.22 × 10(-9)). In addition, we identified and confirmed a genetic association between Takayasu arteritis and the FCGR2A/FCGR3A locus on chromosome 1 (rs10919543, OR = 1.81, p = 5.89 × 10(-12)). The risk allele in this locus results in increased mRNA expression of FCGR2A. We also established the genetic association between IL12B and Takayasu arteritis (rs56167332, OR = 1.54, p = 2.18 × 10(-8)).

A Randomized, Double-Blind Trial of Abatacept (CTLA-4Ig) for the Treatment of Takayasu Arteritis

To compare the efficacy of abatacept to that of placebo for the treatment of giant cell arteritis (GCA).

Sinonasal Wegener granulomatosis: A single-institution experience with 120 cases

Wegener granulomatosis (WG) is intimately associated with the sinonasal tract, with involvement reported in 85% of patients during the course of the disease process. The objectives of the study were: 1) to describe sinonasal symptoms and signs at the time of initial otolaryngologic evaluation; and 2) to review indications and outcomes for rhinologic surgery in WG at our institution.

A Randomized, Double-Blind Trial of Abatacept (CTLA-4Ig) for the Treatment of Giant Cell Arteritis: ABATACEPT FOR THE TREATMENT OF GCA

To compare the efficacy of abatacept to that of placebo for the treatment of Takayasu arteritis (TAK).

Disease Relapses among Patients with Giant Cell Arteritis: A Prospective, Longitudinal Cohort Study

Objective. To evaluate the frequency, timing, and clinical features of relapses in giant cell arteritis (GCA). Methods. Patients with GCA enrolled in a prospective, multicenter, longitudinal study were included in the analysis. Relapse was defined as either new disease activity after a period of remission or worsening disease activity. Results. The study included 128 subjects: 102 women (80%) and 26 men (20%). Mean ± SD age at diagnosis of GCA was 69.9 ± 8.6 years. Mean followup for the cohort was 21.4 ± 13.9 months. Median (interquartile range) duration of disease at study enrollment was 4.6 months (1.2, 16.8). During followup, 59 relapses were observed in 44 patients (34%). Ten patients (8%) experienced 2 or more relapses. The most common symptoms at relapse were headache (42%) and polymyalgia rheumatica (51%), but ischemic (some transient) manifestations (visual symptoms, tongue or jaw claudication, and/or limb claudication) occurred in 29% of relapses (12% cohort). Forty-three relapses (73%) occurred while patients were taking glucocorticoid therapy at a median (range) prednisone dose of 7.5 (0–35) mg. In 21% of relapses, both erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were normal. Among 69 patients enrolled in the cohort with newly diagnosed disease, 24% experienced a first relapse within 12 months after diagnosis. Conclusion. Among patients with GCA, relapses are common, often occurring during treatment. ESR and CRP are frequently normal at times of clinical relapse, highlighting the need for better biomarkers to assess disease activity in GCA. There remains a need for effective therapeutic alternatives to glucocorticoids in GCA.

Surgical interventions and local therapy for Wegener's granulomatosis.

Purpose of reviewThis review discusses the use of interventional procedures to treat manifestations of Wegeners granulomatosis caused by tissue damage and scarring. These manifestations include nasal and paranasal sinus disease, middle ear inflammation, nasolacrimal duct obstruction, orbital inflammatory masses, subglottic stenosis, tracheobronchial disease, and end-stage renal disease. Recent findingsTissue damage caused by inflammation or a cicatricial process represents one of the major sources of morbidity for patients with Wegeners granulomatosis. Some of these manifestations require special interventions used alone or in combination with conventional medical treatment. These interventional procedures may include surgical or endoscopic repair of altered tissue, replacement of damaged organs, or the delivery of topical or injectable medications directly to the site of disease. Distinguishing symptoms caused by active disease from symptoms caused by tissue scarring is challenging and may play a critical role regarding the use of systemic immunosuppressive medications in combination with interventional therapy. SummaryInterventional procedures are indicated in certain manifestations of Wegeners granulomatosis. Distinguishing active Wegeners granulomatosis from inactive Wegeners granulomatosis and recognizing disease manifestations that may be amenable to local interventions can greatly improve the quality of life of patients. However, the evidence supporting the use of many of these interventions is based on small case series or individual reports.

Toll-like receptors mediate induction of hepcidin in mice infected with Borrelia burgdorferi

Hepcidin is the major regulator of systemic iron homeostasis in mammals. Hepcidin is produced mainly by the liver and is increased by inflammation, leading to hypoferremia. We measured serum levels of bioactive hepcidin and its effects on serum iron levels in mice infected with Borrelia burgdorferi. Bioactive hepcidin was elevated in the serum of mice resulting in hypoferremia. Infected mice produced hepcidin in both liver and spleen. Both intact and sonicated B burgdorferi induced hepcidin expression in cultured mouse bone marrrow macrophages. Hepcidin production by cultured macrophages represents a primary transcriptional response stimulated by B burgdorferi and not a secondary consequence of cytokine elaboration. Hepcidin expression induced by B burgdorferi was mediated primarily by activation of Toll-like receptor 2.

New Features of Disease After Diagnosis in 6 Forms of Systemic Vasculitis

Objective. To quantify the occurrence of features of vasculitis that initially present after diagnosis in 6 types of primary vasculitis. Methods. Standardized collection of data on 95 disease manifestations in 6 vasculitides, including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (Churg-Strauss; EGPA), polyarteritis nodosa (PAN), giant cell arteritis (GCA), and Takayasu arteritis (TAK), was obtained within a set of multicenter longitudinal, observational cohorts. For each form of vasculitis, the frequency of disease-specific manifestations at diagnosis was compared to the cumulative frequency of each manifestation. The percentage of patients who initially developed severe manifestations after diagnosis, defined as organ- or life-threatening in the small and medium vessel vasculitides (GPA, MPA, EGPA, PAN) and as ischemic/vascular in the large vessel vasculitides (GCA, TAK), was reported. Results. Out of 838 patients with vasculitis, 490 (59%) experienced ≥ 1 new disease manifestation after diagnosis. On average, patients with vasculitis experienced 1.3 new manifestations after diagnosis (GPA = 1.9, MPA = 1.2, EGPA = 1.5, PAN = 1.2, GCA = 0.7, and TAK = 1.0). New severe manifestations occurred after diagnosis in 224 (27%) out of 838 patients (GPA = 26%, MPA = 19%, EGPA = 21%, PAN = 23%, GCA = 24%, and TAK = 44%). Timing of onset of new manifestations was not significantly associated with disease duration. Conclusion. A majority of patients with vasculitis develop new disease features after diagnosis, including a substantial number of new, severe manifestations. Ongoing assessment of patients with established vasculitis should remain broad in scope.

Vasculitis in patients with inflammatory bowel diseases: A study of 32 patients and systematic review of the literature

BACKGROUND Published small case series suggest that inflammatory bowel disease [IBD; Crohns disease (CD) or ulcerative colitis (UC)] and vasculitis co-occur more frequently than would be expected by chance. OBJECTIVES To describe this association by an analysis of a large cohort of carefully studied patients and through a systematic literature review. METHODS Patients with both IBD and vasculitis enrolled in the Vasculitis Clinical Research Consortium (VCRC) Longitudinal Studies, followed in Canadian Vasculitis research network (CanVasc) centers and/or in the University of Torontos IBD clinic were included in this case series. A systematic literature review of patients with IBD and vasculitis involved a PubMed search through February 2014. The main characteristics of patients with Takayasu arteritis (TAK) and IBD were compared to those in patients with TAK without IBD followed in the VCRC. RESULTS The study identified 32 patients with IBD and vasculitis: 13 with large-vessel vasculitis [LVV; 12 with TAK, 1 with giant cell arteritis (GCA); 8 with CD, 5 with UC]; 8 with ANCA-associated vasculitis [AAV; 6 granulomatosis with polyangiitis (GPA), 2 with eosinophilic granulomatosis with polyangiitis (EGPA)]; 5 with isolated cutaneous vasculitis; and 6 with other vasculitides. Patients with LVV and AAV were mostly female (18/21). The diagnosis of IBD preceded that of vasculitis in 12/13 patients with LVV and 8/8 patients with AAV. The review of the literature identified 306 patients with IBD and vasculitis: 144 with LVV (133 TAK; 87 with IBD preceding LVV), 19 with AAV [14 GPA, 1 EGPA, 4 microscopic polyangiitis (MPA)], 66 with isolated cutaneous vasculitis, and 77 with other vasculitides. Patients with IBD and TAK were younger and had more frequent headaches, constitutional symptoms, or gastrointestinal symptoms compared to those patients in the VCRC who had TAK without IBD. CONCLUSIONS These findings highlight the risk of vasculitis, especially TAK, in patients with IBD (both CD and UC).