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1.
Rheumatology (Oxford) ; 62(9): 3075-3083, 2023 09 01.
Article in English | MEDLINE | ID: mdl-36692142

ABSTRACT

OBJECTIVE: GCA is the commonest primary systemic vasculitis in adults, with significant health economic costs and societal burden. There is wide variation in access to secondary care GCA services, with 34% of hospitals in England not having any formal clinical pathway. Quality standards provide levers for change to improve services. METHODS: The multidisciplinary steering committee were asked to anonymously put forward up to five aspects of service essential for best practice. Responses were qualitatively analysed to identify common themes, subsequently condensed into domain headings, and ranked in order of importance. Quality standards and metrics for each domain were drafted, requiring a minimum 75% agreement. RESULTS: 13 themes were identified from the initial suggestions. Nine quality standards with auditable metrics were developed from the top 10 themes. Patient Access, glucocorticoid use, pathways, ultrasonography, temporal artery biopsy, PET scan access, rheumatology/ophthalmology expertise, education, multidisciplinary working have all been covered in these quality standards. Access to care is a strand that has run through each of the developed standards. An audit tool was developed as part of this exercise. CONCLUSION: These are the first consensus auditable quality standards developed by clinicians from rheumatology and ophthalmology, nursing representatives and involvement of a patient charity. We hope that these standards will be adopted by commissioning bodies to provide levers for change from the improvement of patient care of individuals with GCA.


Subject(s)
Giant Cell Arteritis , Rheumatology , Humans , Giant Cell Arteritis/pathology , Secondary Care , Temporal Arteries/pathology , Positron-Emission Tomography
4.
Eur Heart J Case Rep ; 6(8): ytac307, 2022 Aug.
Article in English | MEDLINE | ID: mdl-36052400

ABSTRACT

Background: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare form of anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis. Cardiac involvement is the major cause of morbidity and mortality in these patients. Early recognition and treatment initiation for such manifestations are key to improved patient outcomes. Case summary: We report the case of a 60-year-old man with a history of therapy-resistant asthma and rhinitis. He presented with acute chest pain, sinus tachycardia, and marked peripheral eosinophilia. Transthoracic echocardiogram (TTE) showed segmental anterior left ventricular (LV) wall motion abnormalities with impaired systolic function (LV ejection fraction 45%) and a small pericardial effusion. Invasive coronary angiography revealed unobstructed coronary arteries. Cardiac magnetic resonance imaging confirmed the TTE findings and demonstrated oedema and active inflammation of the anterior and anteroseptal LV segments [Short inversion time recovery (STIR)-T2] and an unusual pattern of non-ischaemic late gadolinium enhancement extending across multiple coronary territories. Autoantibody testing detected a positive P-ANCA and myeloperoxidase (MPO) antibodies. Overall, the investigation findings supported a diagnosis of ANCA-positive EGPA with acute myocardial involvement. He was initially treated with high-dose corticosteroids, cyclophosphamide, and rituximab. The patient had a good symptomatic and biochemical (normalized troponin T and MPO titre) recovery. In addition, subsequent TTE showed improvement of LV systolic function and resolution of regional wall motion abnormalities. Discussion: In this case, prompt diagnosis facilitated early initiation of immunosuppressive therapy and disease remission. CMR provides non-invasive assessment of myocardial tissue characterization and, used in conjunction with other tools, can be instrumental in detecting myocardial involvement in EGPA.

8.
Lancet Rheumatol ; 3(7): e481-e488, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33942031

ABSTRACT

BACKGROUND: The COVID-19 pandemic has raised numerous questions among patients with immune-mediated inflammatory diseases regarding potential reciprocal effects of COVID-19 and their underlying disease, and potential effects of immunomodulatory therapy on outcomes related to COVID-19. The seroprevalence of SARS-CoV-2 and factors associated with symptomatic COVID-19 in patients with immune-mediated inflammatory diseases are still unclear. The Euro-COVIMID study aimed to determine the serological and clinical prevalence of COVID-19 among patients with immune-mediated inflammatory diseases, as well as factors associated with COVID-19 occurrence and the impact of the pandemic in its management. METHODS: In this multicentre cross-sectional study, patients aged 18 years or older with a clinical diagnosis of rheumatoid arthritis, axial spondyloarthritis, systemic lupus erythematosus, Sjögren's syndrome, or giant cell arteritis were recruited from six tertiary referral centres in France, Germany, Italy, Portugal, Spain, and the UK. Demographics, comorbidities, treatments, and recent disease flares, as well as information on COVID-19 symptoms, were collected through a questionnaire completed by participants. SARS-CoV-2 serology was systematically tested. The main outcome was the serological and clinical prevalence of COVID-19. Factors associated with symptomatic COVID-19 were assessed by multivariable logistic regression, and incidence of recent disease flares, changes in treatments for underlying disease, and the reasons for treatment changes were also assessed. This study is registered with ClinicalTrials.gov, NCT04397237. FINDINGS: Between June 7 and Dec 8, 2020, 3136 patients with an immune-mediated inflammatory disease answered the questionnaire. 3028 patients (median age 58 years [IQR 46-67]; 2239 [73·9%] women and 789 [26·1%] men) with symptomatic COVID-19, serological data, or both were included in analyses. SARS-CoV-2 antibodies were detected in 166 (5·5% [95% CI 4·7-6·4]) of 3018 patients who had serology tests. Symptomatic COVID-19 occurred in 122 (4·0% [95% CI 3·4-4·8]) of 3028 patients, of whom 24 (19·7%) were admitted to hospital and four (3·3%) died. Factors associated with symptomatic COVID-19 were higher concentrations of C-reactive protein (odds ratio 1·18, 95% CI 1·05-1·33; p=0·0063), and higher numbers of recent disease flares (1·27, 1·02-1·58; p=0·030), whereas use of biological therapy was associated with reduced risk (0·51, 0·32-0·82; p=0·0057). At least one disease flare occurred in 654 (21·6%) of 3028 patients. Over the study period, 519 (20·6%) of 2514 patients had treatment changes, of which 125 (24·1%) were due to the pandemic. INTERPRETATION: This study provides key insights into the epidemiology and risk factors of COVID-19 among patients with immune-mediated inflammatory diseases. Overall, immunosuppressants do not seem to be deleterious in this scenario, and the control of inflammatory activity seems to be key when facing the pandemic. FUNDING: Pfizer, Sanofi, Amgen, Galapagos, and Lilly.

10.
Clin Med (Lond) ; 18(2): 180-182, 2018 03.
Article in English | MEDLINE | ID: mdl-29626027

ABSTRACT

A 73-year-old man presented with bilateral leg pain and swelling, and no history of trauma or bleeding disorders. Clinical examination, biochemistry and magnetic resonance imaging of the thighs were suggestive of muscle haematomas. These progressed significantly during the admission, requiring blood transfusion. Normal vascular anatomy on computed tomography, renal and liver function, and absence of infection made a bleeding diathesis more likely. This may be caused by coagulation defects, platelet disorders and vascular fragility. An undetectable serum ascorbic acid level confirmed the clinical suspicion of scurvy, and administration of vitamin C resulted in rapid improvement. Our case provides a structured approach to the diagnosis of bleeding disorders and scurvy, a treatable and potentially fatal disease which is often forgotten.


Subject(s)
Hematoma , Scurvy , Aged , Ascorbic Acid/blood , Hematoma/etiology , Hematoma/pathology , Hematoma/physiopathology , Humans , Male , Scurvy/complications , Scurvy/diagnosis , Scurvy/pathology , Scurvy/physiopathology
11.
BMJ Case Rep ; 20152015 Apr 28.
Article in English | MEDLINE | ID: mdl-25920738

ABSTRACT

An 81-year-old South Asian man normally resident in the UK presented with night sweats for over 2 months on a background of weight loss of 4 kg in 6 months. His medical history was significant for metastatic renal cell carcinoma treated 5 years previously with cytoreductive nephrectomy and adjuvant chemotherapy. Following an abnormal chest radiograph showing an ill-defined right paratracheal mass, a CT scan showed eggshell calcification (circumferential calcification) of enlarged low right paratracheal lymph nodes. An endobronchial ultrasound-guided transbronchial needle aspiration of an involved large paratracheal lymph node showed cytology consistent with metastatic renal cell carcinoma.


Subject(s)
Calcinosis/etiology , Carcinoma, Renal Cell/secondary , Kidney Neoplasms/pathology , Lymph Nodes/pathology , Mediastinum/pathology , Aged, 80 and over , Calcinosis/diagnostic imaging , Carcinoma, Renal Cell/diagnostic imaging , Humans , Kidney Neoplasms/diagnostic imaging , Lymphatic Metastasis/diagnosis , Male , Mediastinum/diagnostic imaging , Sweating , Tomography, X-Ray Computed , Treatment Outcome , Weight Loss
12.
Cardiovasc Res ; 106(3): 509-19, 2015 Jun 01.
Article in English | MEDLINE | ID: mdl-25883219

ABSTRACT

AIMS: Vascular injury leading to endothelial dysfunction is a characteristic feature of chronic renal disease, diabetes mellitus, and systemic inflammatory conditions, and predisposes to apoptosis and atherogenesis. Thus, endothelial dysfunction represents a potential therapeutic target for atherosclerosis prevention. The observation that activity of either protein kinase C epsilon (PKCε) or haem oxygenase-1 (HO-1) enhances endothelial cell (EC) resistance to inflammation and apoptosis led us to test the hypothesis that HO-1 is a downstream target of PKCε. METHODS AND RESULTS: Expression of constitutively active PKCε in human EC significantly increased HO-1 mRNA and protein, whereas conversely aortas or cardiac EC from PKCε-deficient mice exhibited reduced HO-1 when compared with wild-type littermates. Angiotensin II activated PKCε and induced HO-1 via a PKCε-dependent pathway. PKCε activation significantly attenuated TNFα-induced intercellular adhesion molecule-1, and increased resistance to serum starvation-induced apoptosis. These responses were reversed by the HO antagonist zinc protoporphyrin IX. Phosphokinase antibody array analysis identified CREB1((Ser133)) phosphorylation as a PKCε signalling intermediary, and cAMP response element-binding protein 1 (CREB1) siRNA abrogated PKCε-induced HO-1 up-regulation. Likewise, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) was identified as a PKCε target using nuclear translocation and DNA-binding assays, and Nrf2 siRNA prevented PKCε-mediated HO-1 induction. Moreover, depletion of CREB1 inhibited PKCε-induced Nrf2 DNA binding, suggestive of transcriptional co-operation between CREB1 and Nrf2. CONCLUSIONS: PKCε activity in the vascular endothelium regulates HO-1 via a pathway requiring CREB1 and Nrf2. Given the potent protective actions of HO-1, we propose that this mechanism is an important contributor to the emerging role of PKCε in the maintenance of endothelial homeostasis and resistance to injury.


Subject(s)
Apoptosis , Cyclic AMP Response Element-Binding Protein/metabolism , Endothelial Cells/enzymology , Heme Oxygenase-1/biosynthesis , Inflammation/prevention & control , Membrane Proteins/biosynthesis , NF-E2-Related Factor 2/metabolism , Protein Kinase C-epsilon/metabolism , Signal Transduction , Angiotensin II/pharmacology , Animals , Apoptosis/drug effects , Cells, Cultured , Cyclic AMP Response Element-Binding Protein/genetics , Endothelial Cells/drug effects , Endothelial Cells/pathology , Enzyme Activation , Enzyme Induction , Enzyme Inhibitors/pharmacology , Gene Expression Regulation , Heme Oxygenase-1/antagonists & inhibitors , Heme Oxygenase-1/genetics , Human Umbilical Vein Endothelial Cells/drug effects , Human Umbilical Vein Endothelial Cells/enzymology , Human Umbilical Vein Endothelial Cells/pathology , Humans , Inflammation/enzymology , Inflammation/genetics , Inflammation/pathology , Membrane Proteins/antagonists & inhibitors , Membrane Proteins/genetics , Mice, Inbred C57BL , Mice, Knockout , NF-E2-Related Factor 2/genetics , Phosphorylation , Protein Kinase C-epsilon/genetics , Protoporphyrins/pharmacology , RNA Interference , Signal Transduction/drug effects , Time Factors , Transcription, Genetic , Transfection
13.
J Immunol ; 192(9): 4316-27, 2014 May 01.
Article in English | MEDLINE | ID: mdl-24670799

ABSTRACT

Endothelial injury and dysfunction precede accelerated arterial disease in allograft vasculopathy and systemic autoimmune diseases and involve pathogenic Abs and complement. Recent reports suggest that switching to rapamycin from calcineurin antagonists reduces posttransplant vasculopathy and prolongs survival following cardiac transplantion. The majority of these patients also receive statin therapy. We examined potential mechanisms underlying this protective response in human endothelial cells and identified synergy between rapamycin and atorvastatin. Mechanistically, atorvastatin and rapamycin activated a protein kinase Cα, AMP-activated kinase, and CREB-dependent vasculoprotective pathway, which induced decay-accelerating factor (DAF) promoter activity via binding to the cAMP response element, mutation of which attenuated promoter activity. This response significantly increased endothelial cell surface DAF and enhanced protection against complement-mediated injury. Synergy with rapamycin was reproduced by simvastatin, whereas combining atorvastatin with cyclosporine or mycophenolate in place of rapamycin was ineffective. Importantly, synergy was reproduced in vivo, in which only atorvastatin and rapamycin therapy in combination was sufficient to induce DAF on murine aortic endothelium. We believe this pathway represents an important therapeutically inducible vasculoprotective mechanism for diseases mediated by pathogenic Abs and complement, including posttransplant vasculopathy and systemic lupus erythematosus. Although our study focuses on the vascular endothelium, the findings are likely to be broadly applicable, given the diverse cellular expression of DAF.


Subject(s)
Cytoprotection/drug effects , Endothelium, Vascular/drug effects , Heptanoic Acids/administration & dosage , Pyrroles/administration & dosage , Signal Transduction/drug effects , Sirolimus/administration & dosage , AMP-Activated Protein Kinases/metabolism , Animals , Atorvastatin , CD55 Antigens/metabolism , Complement Activation/drug effects , Complement Activation/physiology , Complement System Proteins/metabolism , Cyclic AMP Response Element-Binding Protein/metabolism , Cytoprotection/physiology , Drug Synergism , Endothelium, Vascular/metabolism , Humans , Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage , Immunosuppressive Agents/administration & dosage , Mice , Protein Kinase C/metabolism , Signal Transduction/physiology
14.
Clin Exp Rheumatol ; 32(3 Suppl 82): S11-8, 2014.
Article in English | MEDLINE | ID: mdl-24093733

ABSTRACT

OBJECTIVES: We analysed a large cohort of patients with Takayasu arteritis, seeking robust clinical evidence for prolonged responses to tumour necrosis factor-α (TNF-α) and interleukin-6 receptor (IL-6R) antagonists in severe refractory disease. METHODS: Case notes from ninety-eight patients with Takayasu arteritis were retrospectively reviewed. Drug treatment, laboratory and serial non-invasive imaging data were analysed, and the Indian Takayasu arteritis activity (ITAS) and damage scores (TADs) calculated. RESULTS: Nine patients were treated with biologic therapies. All had previously received high dose prednisolone and ≥1 conventional immunosuppressant. Five patients had failed cyclophosphamide. The patients prescribed biologics had more extensive arterial injury than the remainder of the cohort and persistent active disease (ITAS range 2-9, CRP 12-206 mg/L, TADs 3--1). Eight patients were prescribed anti-TNF-α therapy, three IL-6R blockade. The mean duration of anti-TNF-α treatment was 42 months (maximum 8 years). One patient developed new arterial stenoses while receiving anti-TNF-α and subsequently achieved disease remission with tocilizumab. Two patients have now demonstrated sustained responses to IL-6R inhibition at 19 and 20 months. Following introduction of biologic therapy, serial non-invasive imaging has revealed no significant progression in arterial injury. A significant fall in CRP (p<0.01), prednisolone dose (p<0.01) and ITAS (p<0.01) was observed, with no increase in TADs. CONCLUSIONS: We report for the first time sustained responses to both anti-TNF-α and IL6R antagonists in refractory Takayasu arteritis. As 5/9 patients were cyclophosphamide non-responders, we propose that biologics should now be considered ahead of cyclophosphamide in these young patients.


Subject(s)
Antibodies, Monoclonal, Humanized , Arterial Occlusive Diseases/prevention & control , Receptors, Interleukin-6/antagonists & inhibitors , Takayasu Arteritis , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adolescent , Adult , Antibodies, Monoclonal, Humanized/administration & dosage , Antibodies, Monoclonal, Humanized/adverse effects , Arterial Occlusive Diseases/etiology , Arterial Occlusive Diseases/immunology , Biological Therapy/methods , Cyclophosphamide/administration & dosage , Cyclophosphamide/adverse effects , Disease Progression , Drug Monitoring , Drug Resistance , Female , Follow-Up Studies , Humans , Immunosuppressive Agents/administration & dosage , Immunosuppressive Agents/adverse effects , Magnetic Resonance Angiography/methods , Male , Prednisone/administration & dosage , Prednisone/adverse effects , Retrospective Studies , Severity of Illness Index , Takayasu Arteritis/complications , Takayasu Arteritis/drug therapy , Takayasu Arteritis/epidemiology , Takayasu Arteritis/immunology , Takayasu Arteritis/physiopathology , Time Factors , Treatment Outcome , United Kingdom/epidemiology
16.
Biochem J ; 447(2): 193-204, 2012 Oct 15.
Article in English | MEDLINE | ID: mdl-22849349

ABSTRACT

Vascular endothelial injury predisposes to endothelial dysfunction and atherogenesis. We have investigated the hypothesis that PKCε (protein kinase Cε) is an important upstream regulator of cytoprotective pathways in vascular ECs (endothelial cells). Depletion of PKCε in human ECs reduced expression of the cytoprotective genes A1, A20 and Bcl-2. Conversely, constitutively active PKCε expressed in human ECs increased mRNA and protein levels of these cytoprotective genes, with up-regulation dependent upon ERK1/2 (extracellular-signal-regulated kinase 1/2) activation. Furthermore, inhibition of NF-κB (nuclear factor κB) by the pharmacological antagonist BAY 11-7085 or an IκB (inhibitor of NF-κB) SuperRepressor prevented cytoprotective gene induction. Activation of PKCε enhanced p65 NF-κB DNA binding and elevated NF-κB transcriptional activity. Importantly, although NF-κB activation by PKCε induced cytoprotective genes, it did not up-regulate pro-inflammatory NF-κB targets [E-selectin, VCAM-1 (vascular cell adhesion molecule 1) and ICAM-1 (intercellular adhesion molecule 1)]. Indeed, PKCε exhibited cytoprotective and anti-inflammatory actions, including inhibition of TNFα (tumour necrosis factor α)-induced JNK (c-Jun N-terminal kinase) phosphorylation and ICAM-1 up-regulation, a response attenuated by depletion of A20. Thus we conclude that PKCε plays an essential role in endothelial homoeostasis, acting as an upstream co-ordinator of gene expression through activation of ERK1/2, inhibition of JNK and diversion of the NF-κB pathway to cytoprotective gene induction, and propose that PKCε represents a novel therapeutic target for endothelial dysfunction.


Subject(s)
Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , NF-kappa B/metabolism , Protein Kinase C-epsilon/metabolism , Animals , DNA-Binding Proteins/biosynthesis , Enzyme Activation , Human Umbilical Vein Endothelial Cells , Humans , Intercellular Adhesion Molecule-1/biosynthesis , Intracellular Signaling Peptides and Proteins/biosynthesis , MAP Kinase Kinase 4/metabolism , MAP Kinase Signaling System/physiology , Mice , Minor Histocompatibility Antigens , Nuclear Proteins/biosynthesis , Proto-Oncogene Proteins c-bcl-2/biosynthesis , Tumor Necrosis Factor alpha-Induced Protein 3 , Vascular Cell Adhesion Molecule-1/biosynthesis
18.
BMJ Case Rep ; 20112011 Mar 24.
Article in English | MEDLINE | ID: mdl-22699476

ABSTRACT

Meningeal carcinomatosis (MC) is diffuse infiltration of the meninges by metastatic carcinoma. Though a known complication of solid tumours, it is rarely seen as a presenting feature of such cancers. Here, the authors describe the case of a 64-year-old lady who presented with rapid-onset hearing loss and progressive visual loss, among other cranial nerve palsies. A primary non-small cell lung cancer was later identified by CT, but the diagnosis of MC was only confirmed after cytological analysis of a repeat lumbar puncture. Immunophenotyping of cells from the lung biopsy correlated with cells obtained from cerebrospinal fluid. In view of her rapid clinical deterioration, chemotherapy was not pursued, and the patient was transferred to a hospice 3 weeks after admission.


Subject(s)
Carcinoma, Non-Small-Cell Lung/pathology , Hearing Loss, Sensorineural/etiology , Meningeal Carcinomatosis/diagnosis , Meningeal Carcinomatosis/secondary , Vision Disorders/etiology , Carcinoma, Non-Small-Cell Lung/diagnostic imaging , Cranial Nerve Diseases/diagnosis , Cranial Nerve Diseases/etiology , Female , Hearing Loss, Sensorineural/diagnosis , Humans , Meningeal Carcinomatosis/cerebrospinal fluid , Meningeal Carcinomatosis/complications , Middle Aged , Radiography , Vision Disorders/diagnosis
19.
Free Radic Biol Med ; 48(8): 1013-23, 2010 Apr 15.
Article in English | MEDLINE | ID: mdl-20083195

ABSTRACT

Although nonsteroidal anti-inflammatory drugs (NSAIDs) provide important control of pain and inflammation, they have been overshadowed by concerns regarding atherothrombotic complications. However, celecoxib seems to have a relatively good cardiovascular profile and may improve endothelial function in coronary heart disease. This led us to the hypothesis that celecoxib induces the vasculoprotective enzyme heme oxygenase-1 (HO-1). In human umbilical vein and aortic endothelial cells, 24-48 h treatment with celecoxib induced HO-1 mRNA and protein expression and increased HO-1 enzyme activity. This effect was not seen with rofecoxib or indomethacin. Supplementation of culture medium with iloprost or prostaglandin E(2) failed to reverse celecoxib-mediated HO-1 induction, indicating a cyclooxygenase-independent mechanism. Rather, this action of celecoxib involved generation of mitochondria-derived reactive oxygen species, Akt phosphorylation, and nuclear translocation of the transcription factor Nrf2, with N-acetylcysteine, PI-3K antagonist LY290042, and dominant-negative Akt abrogating the effects. Furthermore, celecoxib-induced HO-1 was inhibited by dominant-negative Nrf2. The functional significance of HO-1 induction was revealed by celecoxib-mediated inhibition of VCAM-1 expression, a response reversed by the HO-1 antagonist zinc protoporphyrin. HO-1 induction provides a molecular mechanism for clinical observations indicating relative freedom from atherothrombotic complications in patients taking celecoxib compared to other NSAIDs with comparable anti-inflammatory activity.


Subject(s)
Heme Oxygenase-1/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Pyrazoles/pharmacology , Sulfonamides/pharmacology , Acetylcysteine/pharmacology , Celecoxib , Chromones/pharmacology , Endothelial Cells/drug effects , Enzyme Induction , Humans , Lactones/pharmacology , Morpholines/pharmacology , NF-E2-Related Factor 2/pharmacology , Oxidation-Reduction , Protein Transport/drug effects , Protoporphyrins/pharmacology , Signal Transduction/drug effects , Sulfones/pharmacology , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Vascular Cell Adhesion Molecule-1/biosynthesis
20.
Cardiovasc Res ; 85(4): 701-10, 2010 Mar 01.
Article in English | MEDLINE | ID: mdl-19903700

ABSTRACT

AIMS: Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptor superfamily of ligand-activated transcriptional regulators. PPARdelta has an established role in metabolism, wound healing, and angiogenesis. However, little is known about its function in endothelial homeostasis. We investigated the role of PPARdelta and its co-activator, PPARgamma co-activator 1alpha (PGC1alpha), in vasculoprotection against oxidant-induced injury via induction of haem oxygenase-1. METHODS AND RESULTS: En face confocal microscopy of murine aortas demonstrated that the PPARdelta-selective ligand GW501516 induced endothelial haem oxygenase-1 expression. In vitro PPARdelta ligands induced a significant increase in haem oxygenase-1 mRNA, protein, and enzyme activity, resulting in enhanced human endothelial cell protection against cellular stress induced by hydrogen peroxide or leptin. Moreover, adenoviral-mediated overexpression of haem oxygenase-1 increased PPARdelta promoter activity and mRNA levels, amplifying the effect of PPARdelta ligands through a positive feedback loop. Mutation of PPAR response element binding sites in the haem oxygenase-1 promoter/enhancer region revealed haem oxygenase-1 to be a direct PPARdelta target gene. Inhibition of either haem oxygenase-1 or PPARdelta abrogated PPARdelta ligand-induced endothelial cytoprotection. Furthermore, siRNA depletion of PGC1alpha demonstrated that this co-regulator acts as an essential PPARdelta transcriptional co-activator for haem oxygenase-1 induction by PPARdelta ligands and its subsequent cytoprotective actions. CONCLUSION: We have identified an important relationship between PPARdelta, PGC1alpha, and haem oxygenase-1, demonstrating that haem oxygenase-1 induction plays an important role in cytoprotective actions of PPARdelta ligands in vascular endothelium. In light of the protective effects of haem oxygenase-1 against atherogenesis, we suggest that PPARdelta represents a potentially important therapeutic target in the vasculature.


Subject(s)
Atherosclerosis/metabolism , Endothelial Cells/metabolism , Heat-Shock Proteins/metabolism , Heme Oxygenase-1/metabolism , Oxidative Stress/physiology , PPAR delta/metabolism , Transcription Factors/metabolism , Animals , Aorta/cytology , Apoptosis/physiology , Atherosclerosis/pathology , Cells, Cultured , Endothelial Cells/cytology , Enzyme Activation/physiology , Feedback, Physiological/drug effects , Feedback, Physiological/physiology , Heat-Shock Proteins/genetics , Heme Oxygenase-1/genetics , Homeostasis/drug effects , Homeostasis/physiology , Humans , Ligands , Mice , Mice, Inbred C57BL , Oxidative Stress/drug effects , PPAR delta/genetics , Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha , RNA, Small Interfering , Thiazoles/pharmacology , Transcription Factors/genetics , Transcriptional Activation/drug effects , Transcriptional Activation/physiology , Umbilical Veins/cytology
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