Pierre-Olivier Girodet

Bronchial smooth muscle remodeling involves calcium-dependent enhanced mitochondrial biogenesis in asthma

Asthma and chronic obstructive pulmonary disease (COPD) are characterized by different patterns of airway remodeling, which all include an increased mass of bronchial smooth muscle (BSM). A remaining major question concerns the mechanisms underlying such a remodeling of BSM. Because mitochondria play a major role in both cell proliferation and apoptosis, we hypothesized that mitochondrial activation in BSM could play a role in this remodeling. We describe that both the mitochondrial mass and oxygen consumption were higher in the BSM from asthmatic subjects than in that from both COPD and controls. This feature, which is specific to asthma, was related to an enhanced mitochondrial biogenesis through up-regulation of peroxisome proliferator-activated receptor γ coactivator (PGC)–1α, nuclear respiratory factor-1, and mitochondrial transcription factor A. The priming event of such activation was an alteration in BSM calcium homeostasis. BSM cell apoptosis was not different in the three groups of subjects. Asthmatic BSM was, however, characterized by increased cell growth and proliferation. Both characteristics were completely abrogated in mitochondria-deficient asthmatic BSM cells. Conversely, in both COPD and control BSM cells, induction of mitochondrial biogenesis reproduced these characteristics. Thus, BSM in asthmatic patients is characterized by an altered calcium homeostasis that increases mitochondrial biogenesis, which, in turn, enhances cell proliferation, leading to airway remodeling.

Tryptase-stimulated human airway smooth muscle cells induce cytokine synthesis and mast cell chemotaxis

Asthmatic patients have higher numbers of mast cells in the smooth muscle layer of airways than normal subjects. Human airway smooth muscle cells (HASMCs) are a source of various cytokines including transforming growth factor β1 (TGF‐β1), which is chemotactic for mast cells. We have thus examined the potential for interaction between HASMCs and mast cells and have investigated, in particular, the hypothesis that after stimulation, HASMCs can induce mast cell chemotaxis through the production of cytokines. Supernatants of HASMCs treated with the major mast cell product tryptase had increased chemotactic activity for the HMC‐1 mast cell line. The effect depended on an intact catalytic site for tryptase and could be induced by a peptide agonist for protease activated receptor 2. Chemotactic activity was related to the synthesis of TGF‐β1 by HASMCs and, to a lesser extent, to stem cell factor. The number of mast cells within the smooth muscle layer of asthmatic patients was closely related to TGF‐β1 expression by smooth muscle. HASMCs may thus be able to stimulate the accumulation of mast cells, and these cells may, in turn, stimulate the secretion of chemotactic factors by HASMCs.

A Proof-of-Concept, Randomized, Controlled Trial of Omalizumab in Patients With Severe, Difficult-to-Control, Nonatopic Asthma

BACKGROUND While up to 50% of patients with severe asthma have no evidence of allergy, IgE has been linked to asthma, irrespective of atopic status. Omalizumab, an anti-IgE monoclonal antibody, is reported to significantly benefit a subset of patients with severe, persistent, allergic asthma. Therefore, we investigated whether omalizumab has biologic and clinical effects in patients with refractory nonatopic asthma. METHODS Forty-one adult patients who, despite daily treatment with or without maintenance oral corticosteroids, had severe, nonatopic, refractory asthma according to GINA (Global Initiative for Asthma) step 4, were randomized to receive omalizumab or placebo in a 1:1 ratio. The primary end point was the change in expression of high-affinity IgE receptor (FcεRI) on blood basophils and plasmacytoid dendritic cells (pDC2) after 16 weeks. The impact of omalizumab on lung function and clinical variables was also examined. RESULTS Compared with placebo, omalizumab resulted in a statistically significant reduction in FcεRI expression on basophils and pDC2 (P < .001). The omalizumab group also showed an overall increase in FEV1 compared with baseline (+250 mL, P = .032; +9.9%, P = .029). A trend toward improvement in global evaluation of treatment effectiveness and asthma exacerbation rate was also observed. CONCLUSIONS Omalizumab negatively regulates FcεRI expression in patients with severe nonatopic asthma, as it does in severe atopic asthma. Omalizumab may have a therapeutic role in severe nonatopic asthma. Nonetheless, our preliminary findings support further investigation to better assess the clinical efficacy of omalizumab. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT01007149; URL: www.clinicaltrials.gov and European Clinical Trials Database, EudraCT; No.: 2009-010937-38; URL: https://www.clinicaltrialsregister.eu.

Atypical antipsychotics: from potassium channels to torsade de pointes and sudden death.

Syncope and sudden death are features of schizophrenia that can be attributed to ischaemic heart disease, the use of antipsychotics (because of proarrhythmia or other reasons such as pharyngeal dyskinesia) or the psychiatric disease itself. Cases have been described with most antipsychotics and have led to the withdrawal, temporary suspension from the market or restricted use of antipsychotics, such as sultopride, droperidol, sertindole or thioridazine.Reviewing the available data shows that all antipsychotics tested affect the cardiac potassium channel, with the concentration that produces 50% inhibition (IC50) ranging from 1 nmol/L (haloperidol) to 6 μmol/L (olanzapine). Experimental in vitro or in vivo electrophysiological studies have shown a dose-dependent increase in the duration of the action potential with various degrees of indicators of serious arrhythmogenicity. However, this does not always translate clinically into an increased duration of the QT interval or increased risk of torsade de pointes or sudden death in clinical trials or pharmacoepidemiological studies. In turn, QT prolongation in clinical trials does not always translate to an increased risk of torsade de pointes or sudden death.The reasons for these apparent discrepancies are unclear and could be related to insufficiently powered field studies, low plasma and tissue drug concentrations with reference to in vitro data or drug effects on other receptors or ion channels that have a protective effect. Alternatively, risks that were not apparent from preclinical or clinical data could be related to the use of the drug in high-risk patients, metabolic interactions or other factors that would only be encountered in large postmarketing populations. The assessment of cardiovascular safety, both preclinical and during premarketing clinical trials, needs to be supported by appropriately powered pharmacoepidemiology studies.

Role of YKL-40 in Bronchial Smooth Muscle Remodeling in Asthma

RATIONALE Bronchial remodeling, including increased bronchial smooth muscle (BSM) mass, contributes to bronchial obstruction in asthma. However, its mechanisms are complex and remain controversial. Recently, a role of the chitinase 3-like 1 protein (YKL-40) has been evoked in asthma. Indeed, YKL-40 concentration was increased in asthmatic serum, and correlated with asthma severity and subepithelial membrane thickness. Nevertheless, the role of YKL-40 on BSM cells remains to be investigated. OBJECTIVES To evaluate whether YKL-40 altered the physiologic properties of BSM cells in asthma in vitro and ex vivo. METHODS We enrolled 40 subjects with asthma, 13 nonsmokers, and 16 smokers. BSM cells were derived from bronchial specimens obtained by either fiberoptic bronchoscopy or lobectomy. We assessed cell proliferation using BrdU, flow cytometry, and cell count; signaling intermediates using Western blot; cell migration using inserts, wound healing, and phalloidin staining; and cell synthesis using ELISA and Western blot. The involvement of protease activated receptor (PAR)-2 was evaluated using blocking antibody and dedicated lentiviral small hairpin RNA. We also determined the BSM area and the YKL-40 staining ex vivo using immunohistochemistry on biopsies from subjects with asthma and control subjects. MEASUREMENTS AND MAIN RESULTS We demonstrated that YKL-40 increased BSM cell proliferation and migration through PAR-2-, AKT-, ERK-, and p38-dependent mechanisms. The increased cell migration was higher in BSM cells of subjects with asthma than that of control subjects. Furthermore, YKL-40 epithelial expression was positively correlated with BSM mass in asthma. CONCLUSIONS This study indicates that YKL-40 promotes BSM cell proliferation and migration through a PAR-2-dependent mechanism.

Inhaled Corticosteroids and Adrenal Insufficiency

AbstractObjective: Adrenal insufficiency (AI) is a potentially life-threatening condition. It is known that high doses of inhaled corticosteroids (ICS) can induce systemic adverse effects. Currently, there are no data on the prevalence of AI associated with the use of ICS. This study aimed to investigate the prevalence and clinical presentation of AI (associated or not associated with exogenous Cushing’s syndrome) in patients who were prescribed ICS by French physicians during the period 2000–5. Methods: All metropolitan French paediatricians, endocrinologists, pulmonologists and intensive care physicians (n = 11 783) were mailed questionnaires requesting information regarding cases of AI associated or not associated with exogenous Cushing’s syndrome between 2000 and 2005. Data collected included patient demographics, oral corticosteroid or ICS used during the year preceding the diagnosis of AI, underlying condition(s), concomitant treatment(s), presenting clinical signs and symptoms, results of laboratory investigations and outcome. The French pharmacovigilance database was screened for spontaneous reports to determine the frequency of AI associated with the use of ICS, using the capturerecapture method. Results: Forty-six cases of AI were identified. Twenty-three cases presented with clinical symptoms of AI alone and 23 with exogenous Cushing’s syndrome. ICS prescribed were fluticasone propionate (n = 24), budesonide (n = 12) and beclometasone dipropionate (n = 5). In 82% (n = 32) of cases for which data were available, ICS were prescribed at high doses. A potential drug interaction was found in 12 cases. Thirteen cases of AI were identified in the French pharmacovigilance database, one of which was common with the questionnaire survey. The capture-recapture method provided an estimation of 598 (95% CI 551, 648) cases of AI associated with the use of ICS for the 2000–5 period in France. Conclusion: The results of this study confirm the occurrence of adrenal insufficiency in patients treated with ICS. Although the prevalence of ICS-induced AI reported in this study is low, the likelihood of under-diagnosis underlines the need to consider this risk in patients when prescribing these drugs.

Quiet Submillimeter MR Imaging of the Lung Is Feasible with a PETRA Sequence at 1.5 T

Quiet submillimeter MR imaging of the lung is feasible with the pointwise encoding time reduction with radial acquisition, or PETRA, sequence at 1.5 T.

The Pivotal Role of Airway Smooth Muscle in Asthma Pathophysiology

Asthma is characterized by the association of airway hyperresponsiveness (AHR), inflammation, and remodelling. The aim of the present article is to review the pivotal role of airway smooth muscle (ASM) in the pathophysiology of asthma. ASM is the main effector of AHR. The mechanisms of AHR in asthma may involve a larger release of contractile mediators and/or a lower release of relaxant mediators, an improved ASM cell excitation/contraction coupling, and/or an alteration in the contraction/load coupling. Beyond its contractile function, ASM is also involved in bronchial inflammation and remodelling. Whereas ASM is a target of the inflammatory process, it can also display proinflammatory and immunomodulatory functions, through its synthetic properties and the expression of a wide range of cell surface molecules. ASM remodelling represents a key feature of asthmatic bronchial remodelling. ASM also plays a role in promoting complementary airway structural alterations, in particular by its synthetic function.

Mast cell adhesion to bronchial smooth muscle in asthma specifically depends on CD51 and CD44 variant 6

To cite this article: Girodet P‐O, Ozier A, Trian T, Begueret H, Ousova O, Vernejoux J‐M, Chanez P, Marthan R, Berger P, Tunon de Lara JM. Mast cell adhesion to bronchial smooth muscle in asthma specifically depends on CD51 and CD44 variant 6. Allergy 2010; 65: 1004–1012.

Phytalgic, a food supplement, vs placebo in patients with osteoarthritis of the knee or hip: a randomised double-blind placebo-controlled clinical trial.

IntroductionThe medicinal treatment of osteoarthritis (OA) is mostly symptomatic to relieve pain and incapacity with analgesics and non-steroidal anti-inflammatory drugs (NSAIDs), drugs with well-known risks. Complementary medicines might reduce the symptoms of OA and decrease the need for NSAIDs. This study tested the effects of a food supplement, Phytalgic®, on pain and function in patients with osteoarthritis and their use of analgesic and NSAIDs.MethodsA randomized double-blind parallel-groups clinical trial compared Phytalgic® (fish-oil, vitamin E, Urtica dioica) to a placebo for three months, in 81 patients with OA of the knee or hip using NSAIDs and/or analgesics regularly. The main outcome measures were use of NSAIDs (in Defined Daily Doses per day - DDD/day) or analgesics (in 500 mg paracetamol-equivalent tablets per week (PET/week) measured each month, and Western Ontario-McMaster University Osteo-Arthritis Index (WOMAC) function scales.ResultsAfter three months of treatment, the mean use of analgesics in the active arm (6.5 PET/week) vs. the placebo arm (16.5) was significantly different (P < 0.001) with a group mean difference of -10.0 (95% CI: -4.9 to -15.1). That of NSAIDs in the active arm (0.4 DDD/day) vs the placebo arm (1.0 DDD/day) was significantly different (P = 0.02) with a group mean difference of - 0.7 DDD/day (95% CI: -0.2 to -1.2). Mean WOMAC scores for pain, stiffness and function in the active arm (respectively 86.5, 41.4 and 301.6) vs the placebo arm (resp. 235.3, 96.3 and 746.5) were significantly different (P < 0.001) with group mean differences respectively of -148.8 (95% CI: -97.7 to -199.9), -54.9 (95% CI: -27.9 to -81.9) and -444.8 (95% CI: -269.1 to -620.4).ConclusionsThe food supplement tested appeared to decrease the need for analgesics and NSAIDs and improve the symptoms of osteoarthritis.Trial registrationClinicaltrials.gov NCT00666523.