Myocardin Is Involved in Mesothelial-Mesenchymal Transition of Human Pleural Mesothelial Cells.

Pleural fibrosis is characterized by severe inflammation of the pleural space and pleural reorganization. Subsequent thickening of the visceral pleura contributes to lung stiffness and impaired lung function. Pleural mesothelial cells (PMCs) can become myofibroblasts via mesothelial-mesenchymal transition (MesoMT) and contribute to pleural organization, fibrosis, and rind formation. However, the mechanisms that underlie MesoMT remain unclear. Here, we investigated the role of myocardin in the induction of MesoMT. Transforming growth factor ß (TGF-ß) and thrombin induced MesoMT and markedly upregulated the expression of myocardin, but not myocardin-related transcription factor A (MRTF-A) or MRTF-B, in human PMCs (HPMCs). TGF-ß stimulation notably induced the nuclear translocation of myocardin in HPMCs, whereas nuclear translocation of MRTF-A and MRTF-B was not observed. Several genes under the control of myocardin were upregulated in cells undergoing MesoMT, an effect that was accompanied by a dramatic cytoskeletal reorganization of HPMCs consistent with a migratory phenotype. Myocardin gene silencing blocked TGF-ß- and thrombin-induced MesoMT. Although myocardin upregulation was blocked, MRTF-A and MRTF-B were unchanged. Myocardin, α-SMA, calponin, and smooth muscle myosin were notably upregulated in the thickened pleura of carbon black/bleomycin and empyema mouse models of fibrosing pleural injury. Similar results were observed in human nonspecific pleuritis. In a TGF-ß mouse model of pleural fibrosis, PMC-specific knockout of myocardin protected against decrements in lung function. Further, TGF-ß-induced pleural thickening was abolished by PMC-specific myocardin knockout, which was accompanied by a marked reduction of myocardin, calponin, and α-SMA expression compared with floxed-myocardin controls. These novel results show that myocardin participates in the development of MesoMT in HPMCs and contributes to the pathogenesis of pleural organization and fibrosis.

Cryptococcus neoformans empyema in a patient receiving ibrutinib for diffuse large B-cell lymphoma and a review of the literature.

We report a case of Cryptococcus neoformans pulmonary infection complicated by empyema in a 79-year-old man with diffuse large B-cell lymphoma treated with R-CHOP and ibrutinib. A literature review identified 25 cases of cryptococcal pleural disease published since 1980. Most cases were caused by the C. neoformans species in immunocompromised hosts with an exudative pleural effusion and lymphocyte-predominant infiltrate. The cryptococcal antigen test was often positive when pleural fluid and serum were tested. The outcome was favourable in most cases with antifungal therapy and either thoracocentesis or surgical resection. We also identified 40 cases of opportunistic infections, most commonly aspergillosis, cryptococcosis and Pneumocystis jirovecii pneumonia, in patients treated with ibrutinib. In vitro studies indicate Bruton tyrosine kinase inhibition impairs phagocyte function and offer a mechanism for the apparent association between ibrutinib and invasive fungal infections.

[Anti-inflammatory drugs and community-acquired pneumonia]. / Anti-inflammatoires et pneumonie aiguë communautaire.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in ambulatory medicine for their analgesic and antipyretic properties and are often used as self-medication. Their use in community-acquired pneumonia is associated with an increased risk of loco-regional complications, especially pleural empyema. Appropriate therapeutic care and hospital admissions are often delayed because of initial improvement of symptoms with NSAIDs. Despite worrying observational data, a causal link remains to be established. Currently, there is no recommendation cautioning against the use of NSAIDs in the management of community-acquired pneumonia.

Accelerated pulmonary nodulosis and sterile pleural effusion in a patient with psoriatic arthropathy during methotrexate therapy: a case report.

Pulmonary nodulosis and sterile pleural exudates are well-known extra-articular manifestations in rheumatoid arthritis patients with a positive rheumatoid factor. In some patients, treatment with methotrexate has been postulated as the trigger of these complications. We report a patient with psoriatic arthropathy, negative RF, negative anticyclic citrulinated peptide antibodies but positive antibodies to cardiolipin who developed massive sterile pleural empyema and multiple cavitary pulmonary nodules during methotrexate treatment. We suggest that awareness of methotrexate-induced lung and pleural complications should be extended to other than rheumatoid arthritis diseases, not necessarily accompanied by rheumatoid factor or anticyclic citrulinated peptide antibodies.

An interesting thinner intoxication case: intrathoracic injection.

Thinners, including aromatic hydrocarbons such as toluene, xylene, and N-hexane, are widely used in industry for the production of plastics, varnish, paint, and glue. Use of these toxic agents frequently leads to chronic intoxication caused by abuse or misuse of solvents, which are usually taken in through inhalation. Thinners may have neurotoxic, myotoxic, hepatotoxic, nephrotoxic, and cardiotoxic systemic effects. The patient described in this report attempted to commit suicide by injecting 10 cc thinner into the left hemithorax. Acute chemical empyema developed at the left hemithorax. No bacterial growth was noted in empyema liquid and blood samples. Empyema was treated with tube thoracostomy, and full remission was observed after 33 d. No systemic toxic signs were noted, other than a low level of hepatotoxicity. Although pleural effusion, atelectasis, and pleural thickening were observed at the acute phase on computed tomography (CT) of the thorax, only pleural thickening persisted on CT of the thorax after 1 y. Investigators could not find a documented case of parenteral use of thinners in the medical literature.

Turpentine oil inhalation leading to lung necrosis and empyema in a toddler.

Household poisons can cause serious damage to the health of children. Turpentine oil, used chiefly as a solvent in paints, varnishes, and waxes; is often placed within easy reach of children during polishing or painting work. It is capable of causing serious toxicity, whether ingested or inhaled. Pulmonary aspiration can lead to lung parenchymal damage and turpentine-associated pneumonia. We report a case of exploratory ingestion and inhalation of turpentine oil in an 18-month-old boy, leading to extensive lung parenchymal damage, formation of multiple abscess cavities, and necrosis treated with decortication and segmental resection.

Eosinophilic "empyema" associated with crack cocaine use.

Smoking of crystalline cocaine, known as "crack" cocaine, has been associated with eosinophilic pneumonitis, but not with pleural effusions. We describe a patient with eosinophilic pneumonitis with an eosinophilic "empyema" after using "crack" cocaine. The illness resolved with corticosteroids. We hypothesised that his effusion would have increased levels of eosinophil cytokines that promote oedema, and found a marked increase in pleural vascular endothelial growth factor (VEGF) and smaller increases in interleukins IL-5, IL-6, and IL-8. In the setting of "crack" use, we suggest that a pleural effusion that appears grossly to be pus should be evaluated for eosinophilic inflammation. Such eosinophilic effusions may respond to corticosteroids alone, consistent with a non-infectious process driven by proinflammatory cytokines.