In Vitro Study of Mutagenesis Induced by Crocidolite-Exposed Alveolar Macrophages NR8383 in Cocultured Big Blue Rat2 Embryonic Fibroblasts

Asbestos-induced mutagenicity in the lung may involve reactive oxygen/nitrogen species (ROS/RNS) released by alveolar macrophages. With the aim of proposing an alternative in vitro mutagenesis test, a coculture system of rat alveolar macrophages (NR8383) and transgenic Big Blue Rat2 embryonic fibroblasts was developed and tested with a crocidolite sample. Crocidolite exposure induced no detectable increase in ROS production from NR8383, contrasting with the oxidative burst that occurred following a brief exposure (1 hour) to zymosan, a known macrophage activator. In separated cocultures, crocidolite and zymosan induced different changes in the gene expressions involved in cellular inflammation in NR8383 and Big Blue. In particular, both particles induced up-regulation of iNOS expression in Big Blue, suggesting the formation of potentially genotoxic nitrogen species. However, crocidolite exposure in separated or mixed cocultures induced no mutagenic effects whereas an increase in Big Blue mutants was detected after exposure to zymosan in mixed cocultures. NR8383 activation by crocidolite is probably insufficient to induce in vitro mutagenic events. The mutagenesis assay based on the coculture of NR8383 and Big Blue cannot be used as an alternative in vitro method to assess the mutagenic properties of asbestos fibres

A randomized trial of long-term remote monitoring of pacemaker recipients (The COMPAS trial)

International audienceAIMS: Professional practice guidelines recommend that pacemaker recipients be followed regularly. However, the majority of scheduled ambulatory visits is unproductive and imposes a heavy burden on the health-care system. METHODS AND RESULTS: The COMPAS randomized, multicentre, non-inferiority trial examined the safety of long-term remote monitoring of pacemakers. Between December 2005 and January 2008, 538 patients were randomly assigned to remote monitoring follow-up (active group) vs. standard care (control group). The primary objective was to confirm that the proportion of patients who experienced at least one major adverse event (MAE), including all-cause death and hospitalizations for device-related or cardiovascular adverse events, was not >7% higher in the active than in the control group. MAE-free survivals and quality of life were compared in both groups. The characteristics of the study groups were similar. Over a follow-up of 18.3 months, 17.3% of patients in the active and 19.1% in the control group experienced at least one MAE (P < 0.01 for non-inferiority). Hospitalizations for atrial arrhythmias (6 vs. 18) and strokes (2 vs. 8) were fewer (P < 0.05), and the number of interim ambulatory visits was 56% lower (P < 0.001) in the active than the control group. Changes in pacemaker programming or drug regimens were made in 62% of visits in the active vs. 29% in the control group (P < 0.001). Quality of life remained unchanged in both groups. CONCLUSION: Remote monitoring was a safe alternative to conventional care and significantly lowered the number of ambulatory visits during long-term follow-up of permanently paced patients. ClinicalTrials.gov identifier: NCT00989326

Effect of Cyclosporine and Rifampin on the Pharmacokinetics of Macitentan, a Tissue-Targeting Dual Endothelin Receptor Antagonist

Macitentan is a dual endothelin receptor antagonist under phase 3 investigation in pulmonary arterial hypertension. We investigated the effect of cyclosporine (Cs) and rifampin on the pharmacokinetics of macitentan and its metabolites ACT-132577 and ACT-373898 in healthy male subjects. In addition, in vitro studies were performed to investigate interactions between macitentan and its active metabolite ACT-132577 with human organic anion-transporting polypeptides (OATPs). The clinical study (AC-055-111) was conducted as a two-part, one-sequence, crossover study. Ten subjects in each part received multiple-dose macitentan followed by multiple-dose co-administration of Cs (part A) or rifampin (part B). In the presence of Cs, steady-state area under the plasma concentration–time profiles during a dose interval (AUCτ) for macitentan and ACT-373898 increased 10% and 7%, respectively, and decreased 3% for ACT-132577. Steady-state AUCτ of macitentan and ACT-373898 in the presence of rifampin decreased 79% and 64%, respectively. For ACT-132577, no relevant difference in AUCτ between the two treatments was observed. Macitentan co-administered with Cs or rifampin was well tolerated. The complementary in vitro studies demonstrated no marked differences in uptake rates of macitentan and ACT-132577 between the wild-type and OATP over-expressing cells over the concentration range tested. Concomitant treatment with Cs did not have any clinically relevant effect on the exposure to macitentan or its metabolites, at steady-state. Concomitant treatment with rifampin reduced significantly the exposure to macitentan and its metabolite ACT-373898 at steady-state but did not affect the exposure to the active metabolite ACT-132577 to a clinically relevant extent