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M Humbert

Publications and source records attributed to M Humbert.

At least 19 recordsLinked to original sources
PubMed2006

Fractalkine-induced smooth muscle cell proliferation in pulmonary hypertension.

Pulmonary hypertension is characterised by a progressive increase in pulmonary arterial resistance due to endothelial and smooth muscle cell proliferation resulting in chronic obstruction of small pulmonary arteries. There is evidence that inflammatory mechanisms may contribute to the pathogenesis of human and experimental pulmonary hypertension. The aim of the study was to address the role of fractalkine (CX3CL1) in the inflammatory responses and pulmonary vascular remodelling of a monocrotaline-induced pulmonary hypertension model. The expression of CX3CL1 and its receptor CX3CR1 was studied in monocrotaline-induced pulmonary hypertension by means of immunohistochemistry and quantitative reverse-transcription PCR on laser-captured microdissected pulmonary arteries. It was demonstrated that CX3CL1 was expressed by inflammatory cells surrounding pulmonary arterial lesions and that smooth muscle cells from these vessels had increased CX3CR1 expression. It was then shown that cultured rat pulmonary artery smooth muscle cells expressed CX3CR1 and that CX3CL1 induced proliferation but not migration of these cells. In conclusion, the current authors proposed that fractalkine may act as a growth factor for pulmonary artery smooth muscle cells. Chemokines may thus play a role in pulmonary artery remodelling.

Analysis of Variance↗
PubMed2006

Pulmonary artery distensibility in pulmonary arterial hypertension: an MRI pilot study.

Pulmonary arterial hypertension (PAH) is a disease of the small vessels in which there is a substantial increase in pulmonary vascular resistance leading to right ventricle failure and death. Invasive haemodynamic evaluation is mandatory not only for diagnosis confirmation but also to address prognosis and eligibility for the use of calcium-channel blockers through an acute vasodilator challenge. Noninvasive surrogate response markers to the acute vasodilator test have been sought. In the present study, the relationship between pulmonary artery distensibility, assessed using magnetic resonance imaging (MRI), and response to acute vasodilator tests was investigated. In total, 19 patients diagnosed with idiopathic PAH without any specific treatment were evaluated. Within a 48-h window after pulmonary artery catheterisation, patients underwent cardiac MRI. Cardiac index, calculated after the determination (invasively and noninvasively) of cardiac output, showed excellent correlation, as did right atrial pressure and right ventricle ejection fraction. Pulmonary artery distensibility was significantly higher in responders. A receiver operating characteristic curve analysis has shown that 10% distensibility was able to differentiate responders from nonresponders with 100% sensitivity and 56% specificity. The present findings suggest that magnetic resonance imaging and pulmonary artery distensibility may be useful noninvasive tools for the evaluation of patients with pulmonary hypertension.

Administration, Inhalation↗
PubMed2006

Dendritic cell recruitment in lesions of human and experimental pulmonary hypertension.

In the present study, the hypothesis that dendritic cells (DCs), key players in immunity and tolerance, might be involved in the immunopathology of idiopathic pulmonary arterial hypertension (IPAH) was tested. The phenotype and localisation of DCs were characterised by immunohistochemistry and double-labelling immunofluorescence in lung samples from controls, human IPAH patients and an experimental pulmonary hypertension model (monocrotaline-exposed rats). As compared with controls, morphometric analysis demonstrated increased numbers of dendritic cell-specific intercellular adhesion molecule-grabbing nonintegrin (DC-SIGN)-positive cells in muscular pulmonary arteries in IPAH and OX-62-positive DCs in monocrotaline-induced pulmonary hypertension. In human samples, the mean+/-SEM number of DC-SIGN-positive cells.artery(-1) of 100-300 microm diameter was 1.4+/-0.4 in controls versus 26.4+/-2.7 in IPAH. In rats, the number of OX-62-positive cells.artery(-1) of 50-150 microm diameter was 0.5+/-0.2 in controls, and 0.7+/-0.5, 3.1+/-0.5 and 8.4+/-0.6 at day 7, 14 and 28 after monocrotaline exposure, respectively. Human complex lesions of muscular pulmonary arteries showed transmural DC infiltration. Phenotyping revealed an immature DC profile in human and experimental pulmonary hypertension. The results support the concept that immature dendritic cells accumulate in remodelled pulmonary vessels and hence could be involved in the immunopathology of pulmonary hypertension.

Animals↗
PubMed2006

Bosentan treatment for pulmonary arterial hypertension related to connective tissue disease: a subgroup analysis of the pivotal clinical trials and their open-label extensions.

BACKGROUND: Endothelin-1 is considered to be a central pathogenic factor in connective tissue diseases (CTDs) such as systemic sclerosis (SSc), leading to vasoconstriction, fibrosis, hypertrophy and inflammation. A frequent complication of CTD is pulmonary arterial hypertension (PAH), which has a major effect on functioning and quality of life, and is associated with a particularly poor prognosis. OBJECTIVE: To present a subgroup analysis that summarises experiences from the pivotal studies and their open-label extensions with the oral dual endothelin-1 receptor antagonist bosentan in patients with PAH and CTD, mostly SSc and lupus erythematosus. METHODS: 66 patients with PAH secondary to CTD, in World Health Organization functional class III or IV, were randomised to two double-blind, placebo-controlled studies and followed up for 12 and 16 weeks, respectively. The primary end point was change in exercise capacity, assessed using the 6-min walk test. In both studies and their extensions, survival was assessed from start of treatment to death or data cut-off and analysed as Kaplan-Meier estimates. RESULTS: 44 patients with PAH secondary to CTD who were treated with bosentan were stable in 6-min walk distance at the end of the study (+19.5 m, 95% confidence interval (CI) -3.2 to 42.2), whereas patients treated with placebo deteriorated (-2.6 m, 95% CI -54.0 to 48.7). 64 patients subsequently received bosentan in an open-label long-term extension study. Mean (standard deviation (SD)) exposure to bosentan was 1.6 (0.9) years, and duration of observation was 1.8 (0.8) years. 8 (16%) patients received epoprostenol as add-on treatment and 7 (14%) after discontinuation of bosentan. Survival in those receiving bosentan was 85.9% after 1 year and 73.4% after 2 years. CONCLUSION: Short-term bosentan treatment in a subgroup of patients with PAH secondary to CTD seems to have a favourable effect compared with placebo. The long-term follow-up of these patients suggests that first-line bosentan, with the subsequent addition of other PAH treatments if required, is safe for long-term treatment and may have a positive effect on outcome.

Adolescent↗
PubMed2006

Antibodies to fibroblasts in idiopathic and scleroderma-associated pulmonary hypertension.

The aim of the present study was to investigate the presence of anti-fibroblast antibodies in patients with idiopathic or scleroderma-associated pulmonary arterial hypertension (PAH) and healthy controls. PAH was documented by right-heart catheterisation (mean pulmonary artery pressure at rest >25 mmHg). Serum immunoglobulin (Ig)G and IgM reactivities of patients with idiopathic PAH (n = 35), scleroderma-associated PAH (n = 10), diffuse (n = 10) or limited cutaneous (n = 10) scleroderma without PAH and age- and sex-matched healthy individuals (n = 65) were analysed by cell-based ELISA and immunoblotting on normal human fibroblasts. As assessed by ELISA, 14 out of 35 (40%) patients with idiopathic PAH and three out of 10 (30%) patients with scleroderma-associated PAH expressed anti-fibroblast IgG antibodies. IgG from all individuals bound to one major 40-kDa protein band. IgG from patients with idiopathic PAH bound to two 25- and 60-kDa bands with a higher intensity than IgG from other individuals. In conclusion, immunoglobulin G anti-fibroblast antibodies are present in the serum of patients with pulmonary arterial hypertension. Immunoglobulin G from patients with idiopathic pulmonary arterial hypertension or scleroderma-associated pulmonary arterial hypertension express distinct reactivity profiles with fibroblasts antigens, suggesting distinct target antigens.

Adult↗
PubMed2006

The efficacy of bosentan in inoperable chronic thromboembolic pulmonary hypertension: a 1-year follow-up study.

The treatment of choice for chronic thromboembolic pulmonary hypertension (CTEPH) is pulmonary endarterectomy (PEA). However, many patients develop a severe progressive small vessel pulmonary arteriopathy that is inaccessible to surgical intervention and is associated with poor survival. The purpose of the present study was to evaluate the medium-term efficacy and safety of the dual endothelin receptor antagonist, bosentan, in inoperable CTEPH. Forty-seven patients with inoperable CTEPH (distal disease or persistent pulmonary hypertension following PEA) underwent evaluation after 1 yr of bosentan therapy. Outcomes included assessment of 6-min walk test (6MWT), haemodynamics and World Health Organization functional classification. Monitoring of serious adverse effects and changes in therapy was undertaken. Patients showed sustained improvements in 6MWT (49+/-8 m), functional classification, cardiac index (+0.2+/-0.07 L.min(-1).m(-2)) and total pulmonary resistance (-139+/-42 dyn.s.cm(-5)). Those patients with persisting pulmonary hypertension following PEA showed the greatest improvement. One-yr survival was 96%, and bosentan was well tolerated with only one patient developing deranged liver function. Although all patients with chronic thromboembolic pulmonary hypertension should be considered for pulmonary endarterectomy, bosentan provides an alternative medical therapy to improve function and delay the progression of this devastating disease in those in whom surgery is not suitable.

Adult↗
PubMed2006

[Update on the pathomorphological assessment of vasculopathies in pulmonary arterial hypertension].

Pulmonary arterial hypertension (PAH) is a term which has recently been redefined and includes idiopathic pulmonary arterial hypertension, familial pulmonary arterial hypertension PAH related to specific pathological conditions (e.g. connective tissue diseases), as well as PAH caused by veno-occlusive disease or capillary hemangiomatosis. The clinical manifestation seems to be related to a peculiar pathological anatomy involving small, muscular pulmonary arteries, capillaries and veins. In addition to common hypertrophy of the tunica media, other vascular compartments may also be affected by intimal thickening or adventitial fibrosis. Moreover, complex lesions, such as so called plexiform lesions and arteritis can be present in certain forms of the disease. While the recent identification of responsible gene mutations in subgroups of patients have shed some light on disease evolution, therapeutic strategies must currently rely on vasodilative and antimitogenic drugs acting on the intimal and medial level of the affected pulmonary vessels. The clinical outcome of patients suffering from PAH remains poor, underlining our need for a better comprehension of disease pathophysiology, and thus for the characterization of specific histomorphological patterns.

Hemangioma, Capillary↗
PubMed2006

[Characteristics of mild asthma: clinical signs and medication use. Position statement of the Mild Asthma Working Group (174)].

OBJECTIVE: To update on the state of knowledge in mild asthma (intermittent and persistent mild asthma, according to the GINA classification) review the literature, and the position statement of the French Mild Asthma Working Group. METHODS: The French Mild Asthma Working Group (11 lung specialists, 4 paediatricians, 1 pharmacologist, and 1 general practitioner) selected, analysed, and summarised the literature on the descriptive epidemiology, physiopathology, clinical signs, and management of mild asthma. The position of the working group on the descriptive epidemiology (causal factors excluded) and the nature of the bronchial inflammation has been presented in a previous article. The present article focuses on the clinical features of mild asthma and the use of medication for it. RESULTS: Mild asthma was more frequent, more symptomatic, and less well controlled in children than in adults. Its generally benign evolution may in some (<10%) cases be complicated by severe episodes. Patients with mild persistent asthma require controller medication every day: permanent low-dose inhaled corticosteroid monotherapy is the reference foundation treatment for persistent mild asthma. CONCLUSIONS: The present findings should help clinicians and guide them in their approach to managing this condition.

Administration, Inhalation↗
PubMed2006

Bosentan for the treatment of pulmonary arterial hypertension associated with congenital heart defects.

BACKGROUND: Bosentan is an effective first-line therapy in New York Heart Association (NYHA) III patients with idiopathic pulmonary arterial hypertension (PAH). Pre-clinical data support the rationale for the potential benefit of bosentan in PAH associated with congenital heart disease (CHD). MATERIALS AND METHODS: We performed a retrospective analysis of patients with PAH-associated CHD who were treated with bosentan on top of conventional therapy. Bosentan was started at 62.5 mg bid for 4 weeks, then titrated to 125 mg bid. New York Heart Association (NYHA) functional class, 6-min walking distance (6MWD), Borg dyspnoea index, arterial oxygen saturation and cardiopulmonary haemodynamic data (cardiac output, pulmonary blood flow and systemic and pulmonary vascular resistances) were collected at baseline and at follow up. RESULTS: Twenty-seven patients (23 females, mean 35 +/- 15 years) with NYHA class III-IV PAH-associated CHD (not repaired in 23 cases) were treated with bosentan for a mean 18.3 +/- 9.9 months. Bosentan improved 6MWD from 298 +/- 92 m at baseline to 355 +/- 82 m at 3 months (P = 0.0002) and to 364 +/- 92 m (P = 0.0001) at the last follow up (mean 15.2 +/- 9.7 months). At the last follow up, 13 patients had improved (= 1 NYHA class) and 14 remained stable. A favourable effect was observed in pulmonary blood flow and pulmonary vascular resistance for the 11 available patients. No change in pulse oximetry or liver enzyme elevation was reported. CONCLUSIONS: Bosentan improves exercise capacity, functional class and haemodynamics in most patients with PAH-associated CHD, without serious side-effects, suggesting bosentan may be an important treatment option for these patients.

Adolescent↗
PubMed2006

Themes in allergy.

Explore the source record for details and available documents.

Developed Countries↗
PubMed2006

Dexamethasone and IL-10 stimulate glucocorticoid-induced leucine zipper synthesis by human mast cells.

BACKGROUND: Glucocorticoids (GCs) decrease tissue mast cell (MC) number and prevent their activation via their high-affinity IgE receptor. Glucocorticoid-induced leucine zipper (GILZ) is one of the GC-induced genes, which inhibits the functions of the transcriptional activators AP-1 and NF-kappaB. GILZ appears to be a critical actor in the anti-inflammatory and immunosuppressive effects of GCs in human T lymphocytes, macrophages and dendritic cells. AIMS OF THE STUDY: We investigated whether GILZ was produced by human MCs and whether GILZ synthesis was stimulated by GCs. We also investigated whether GILZ production was modulated by (i) IL-10, because of its common immunosuppressive properties with GCs, (ii) histamine because of its pro-inflammatory properties and (iii) IL-4 and IL-5 because of their ability to favour MC survival and proliferation with SCF. METHODS: The human MC lines HMC-1 5C6 and LAD-2, and cord blood-derived MCs (CB-MCs) were cultured alone or in the presence of GCs, IL-10, histamine, IL-4 or IL-5. The expression of GILZ was evaluated by using RT-PCR, Western blotting or immunocytochemistry. RESULTS: We found that human MC lines and CB-MCs constitutively produce GILZ. We also show that GCs and IL-10 stimulate GILZ production by human MCs. Our present results indicate that histamine, IL-4 and IL-5 alone or in combination with SCF do not downregulate GILZ production by MCs. CONCLUSIONS: These results show that GCs and IL-10 stimulate GILZ production by human MCs. As GILZ mediates anti-inflammatory effects of GCs in immune cells, we speculate that GILZ could account for the deactivation of MCs by GCs and IL-10.

Cell Line↗
PubMed2006

Heart rate responses during the 6-minute walk test in pulmonary arterial hypertension.

Patients with pulmonary arterial hypertension (PAH) exhibit a limited increase in stroke volume on exercise, and the heart rate (HR) increases may reflect the main mechanism that allows cardiac output to increase. The current prospective study documented the contribution of HR to the 6-min walking distance (6MWD) in idiopathic (IPAH) and nonidiopathic PAH. Eighty-three patients (46 IPAH and 37 nonidiopathic PAH) underwent haemodynamic evaluation and a 6MWD test. Chronotropic response (peak walking HR minus resting HR) and peripheral oxygen saturation were monitored. Fifty-seven patients were also assessed after 5+/-2 months of treatment (bosentan n = 38, epoprostenol n = 14, bosentan-epoprostenol n = 3, iloprost n = 2). Before treatment, the 6MWD was related to numerous demographic, haemodynamic and walking test characteristics. Stepwise regression analysis indicated that the only factors significantly associated with the 6MWD were stroke volume and chronotropic response in both IPAH and nonidiopathic PAH patients. Following treatment, changes in 6MWD were significantly related to changes in chronotropic response in both IPAH and nonidiopathic PAH. In conclusion, baseline stroke volume and chronotropic response were independently associated with the 6-min walking distance in pulmonary arterial hypertension. The lack of chronotropic response may reflect the loss in normal physiological reserve in more unwell patients.

Analysis of Variance↗
PubMed2006

Occult alveolar haemorrhage in pulmonary veno-occlusive disease.

Pulmonary veno-occlusive disease (PVOD) is a rare cause of pulmonary arterial hypertension that affects predominantly post-capillary pulmonary vessels. A major concern with PVOD is the poor response to available therapies and the risk of pulmonary oedema with continuous intravenous epoprostenol. The present authors hypothesised that alveolar haemorrhage may be a characteristic feature of pulmonary veno-occlusive disease, as compared with other forms of pulmonary arterial hypertension that predominantly involve pre-capillary pulmonary arteries. This paper reports a series of 19 patients with either PVOD (n = 8) or idiopathic pulmonary arterial hypertension (IPAH; n = 11) who underwent bronchoalveolar lavage. Cytological analyses were performed and differential counts were made on Perls-stained preparations. The Golde score was used to assess alveolar haemorrhage. As compared with IPAH, PVOD was characterised by a higher percentage of haemosiderin-laden macrophages (40+/-37 versus 3+/-6%), resulting in elevated Golde scores (81+/-88 versus 4+/-10). It was concluded that occult alveolar haemorrhage is a common feature of pulmonary veno-occlusive disease. Detecting occult alveolar haemorrhage may be of interest in the diagnostic approach of pulmonary veno-occlusive disease.

Adult↗
PubMed2006

[Characteristics of mild asthma: descriptive epidemiology and nature of bronchial inflammation. Position of the Mild Asthma Working Group].

INTRODUCTION: Update on the state of knowledge in the mild asthma (intermittent and persistent mild asthma, according to the GINA classification) literature, and position of a French Mild Asthma Working Group. STATE OF THE ART: The French Mild Asthma Working Group (11 lung specialists, 4 paediatricians, 1 pharmacologist, and 1 general practitioner) selected, analysed, and summarised the literature on the epidemiology, physiopathology, clinical signs, and management of mild asthma. The present article shows the position of the working group on mild asthma descriptive epidemiology (causal factors excluded) and the nature of the bronchial inflammation. Clinical signs and medicinal treatments will be presented in a second article. PERSPECTIVES: Between 50% and 75% of asthma patients, depending on the study, present mild asthma. Childhood-to-adulthood cohort monitoring found severity to be unchanged over developmental time. Its generally benign evolution may in some (<10%) cases be complicated by severe episodes. Inflammation and airway-wall remodelling were always found, although of variable intensity, and non-specific (except for absence of infiltration by polymorphonuclear neutrophils). Corticosteroid therapy by inhalation reduces bronchial inflammation, but with little impact on airway-wall remodelling. CONCLUSION: The present findings should help clinicians in identifying and understanding mild asthma.

Adrenal Cortex Hormones↗
PubMed2005

[Diagnosis and classification of pulmonary arterial hypertension].

The clinical classification of types of pulmonary hypertension has made it possible to better standardize the approach to the diagnosis and treatment of patients, to perform clinical studies among homogeneous patients, and to discover common laboratory abnormalities that may serve as markers or help elucidate mechanisms of disease. Pulmonary arterial hypertension groups together different diseases that affect the small-caliber pulmonary arteries and lead to a progressive increase in pulmonary arterial resistance and right heart failure. A specific diagnosis of pulmonary arterial hypertension is generally based on a detailed and methodical clinical evaluation. Pulmonary biopsy is rarely indicated. Work-up in a center specialized in the management of this disease is frequently appropriate when the cause of the hypertension is not clear or when a specific treatment is envisaged.

Diagnostic Imaging↗