Organic dust-induced lung injury and repair: Bi-directional regulation by TNFα and IL-10.

Exposure to organic dust increases chronic airway inflammatory disorders. Effective treatment strategies are lacking. It has been reported that hog barn dust extracts (HDE) induce TNFα through protein kinase C (PKC) activation and that lung inflammation is enhanced in scavenger receptor A (SRA/CD204) knockout (KO) mice following HDE. Because interleukin (IL)-10 production can limit excessive inflammation, it was hypothesized here that HDE-induced IL-10 would require CD204 to effect inflammatory responses. C57BL/6 wild-type (WT), SRA KO, and IL-10 KO mice were intranasally challenged daily for 8 days with HDE and subsequently rested for 3 days with/without recombinant IL-10 (rIL-10) treatment. Primary peritoneal macrophages (PM) and murine alveolar macrophages (MH-S cells) were treated in vitro with HDE, SRA ligand (fucoidan), rIL-10, and/or PKC isoform inhibitors. HDE induced in vivo lung IL-10 in WT, but not SRA KO mice, and similar trends were demonstrated in isolated PM from same treated mice. Lung lymphocyte aggregates and neutrophils were elevated in in vivo HDE-treated SRA and IL-10 KO mice after a 3-d recovery, and treatment during recovery with rIL-10 abrogated these responses. In vitro rIL-10 treatment reduced HDE-stimulated TNFα release in MH-S and WT PM. In SRA KO macrophages, there was reduced IL-10 and PKC zeta (ζ) activity and increased TNFα following in vitro HDE stimulation. Similarly, blocking SRA (24 hr fucoidan pre-treatment) resulted in enhanced HDE-stimulated macrophage TNFα and decreased IL-10 and PKCζ activation. PKCζ inhibitors blocked HDE-stimulated IL-10, but not TNFα. Collectively, HDE stimulates IL-10 by an SRA- and PKCζ-dependent mechanism to regulate TNFα. Enhancing resolution of dust-mediated lung inflammation through targeting IL-10 and/or SRA may represent new approaches to therapeutic interventions.

Assessment of the effects of levosimendan and thymoquinone on lung injury after myocardial ischemia reperfusion in rats.

AIM: The aim of this study was to investigate the effects of levosimendan and thymoquinone (TQ) on lung injury after myocardial ischemia/reperfusion (I/R). MATERIALS AND METHODS: Twenty-four Wistar albino rats were included in the study. The animals were randomly assigned to 1 of 4 experimental groups. In Group C (control group), left anterior descending artery was not occluded or reperfused. Myocardial I/R was induced by ligation of the left anterior descending artery for 30 min, followed by 2 h of reperfusion in the I/R, I/R-levosimendan (24 µg/kg) (IRL) group, and I/R-thymoquinone (0.2 mL/kg) (IRTQ) group. Tissue samples taken from the lungs of rats were histochemically stained with H&E and immunohistochemically stained with p53, Bcl 2, Bax, and caspase 3 primer antibodies. RESULTS: Increased expression of p53 and Bax was observed (4+), especially in the I/R group. In IRTQ and IRL groups, expression was also observed at various locations (2+, 3+). H&E staining revealed that that the lungs were severely damaged and the walls of the alveoli were too thick, the number of areas examined was increased during the evaluation. Caspase 3 expression was observed to be at an (1+, 2+) intensity that was usually weak and diffuse in multiple areas. Bcl 2 was not found to be expressed in any of the tissues. H&E staining revealed that that the lungs were severely damaged in the I/R group, with the walls of the channels and alveoli thickened and edematous, and also an intense inflammatory cell migration was observed. Immunohistochemical staining was more prominent in inflammatory areas and structures around the terminal bronchioles. CONCLUSION: The findings in our study have shown that administration of levosimendan and TQ during I/R increases expression of caspase 3, p53, and Bax in lung tissue and has a protective effect on lung as distant organ. We suggest that findings of this study be elucidated with further large-scale clinical studies.

Pulmonary injury associated with radiation therapy - Assessment, complications and therapeutic targets.

Pulmonary injury is more common in patients undergoing radiation therapy for lungs and other thoracic malignancies. Recently with the use of most-advanced technologies powerful doses of radiation can be delivered directly to tumor site with exquisite precision. The awareness of technical and clinical parameters that influence the chance of radiation induced lung injury is important to guide patient selection and toxicity minimization strategies. At the cellular level, radiation activates free radical production, leading to DNA damage, apoptosis, cell cycle changes, and reduced cell survival. Preclinical research shows the potential for therapies targeting transforming growth factor-ß (TGF-B), Toll like receptor (TLRs), Tumour necrosis factor-alpha (TNF-alpha), Interferon gamma (IFN-γ) and so on that may restore lung function. At present Amifostine (WR-2721) is the only approved broad spectrum radioprotector in use for patients undergoing radiation therapy. Newer techniques also offer the opportunity to identify new biomarkers and new targets for interventions to prevent or ameliorate these late effects of lung damage.

Radiation induced lung injury: prediction, assessment and management.

Radiation induced lung injury has long been considered a treatment limiting factor for patients requiring thoracic radiation. This radiation induced lung injury happens early as well as late. Radiation induced lung injury can occur in two phases viz. early (<6 months) when it is called radiation pneumonitis and late (>6 months) when it is called radiation induced lung fibrosis. There are multiple factors that can be patient, disease or treatment related that predict the incidence and severity of radiation pneumonitis. Radiation induced damage to the type I pneumocytes is the triggering factor to initiate such reactions. Over the years, radiation therapy has witnessed a paradigm shift in radiation planning and delivery and successfully reduced the incidence of lung injury. Radiation pneumonitis is usually a diagnosis of exclusion. Steroids, ACE inhibitors and pentoxyphylline constitute the cornerstone of therapy. Radiation induced lung fibrosis is another challenging aspect. The pathophysiology of radiation fibrosis includes continuing inflammation and microvascular changes due to pro-angiogenic and pro- fibrogenic stimuli resembling those in adult bronchiectasis. General supportive management, mobilization of airway secretions, anti-inflammatory therapy and management of acute exacerbations remains the treatment option. Radiation induced lung injury is an inevitable accompaniment of thoracic radiation.