Acute respiratory distress syndrome: an overview for physician assistants

Arctigenin Protects against Lipopolysaccharide-Induced Pulmonary Oxidative Stress and Inflammation in a Mouse Model via Suppression of MAPK, HO-1, and iNOS Signaling

Arctigenin, a bioactive component of Arctium lappa (Nubang), has anti-inflammatory activity. Here, we investigated the effects of arctigenin on lipopolysaccharide (LPS)-induced acute lung injury. Mice were divided into four groups: control, LPS, LPS + DMSO, and LPS + Arctigenin. Mice in the LPS + Arctigenin group were injected intraperitoneally with 50 mg/kg of arctigenin 1 h before an intratracheal administration of LPS (5 mg/kg). Lung tissues and bronchoalveolar lavage fluids (BALFs) were collected. Histological changes of the lung were analyzed by hematoxylin and eosin staining. Arctigenin decreased LPS-induced acute lung inflammation, infiltration of inflammatory cells into BALF, and production of pro-inflammatory cytokines. Moreover, arctigenin pretreatment reduced the malondialdehyde level and increased superoxide dismutase and catalase activities and glutathione peroxidase/glutathione disulfide ratio in the lung. Mechanically, arctigenin significantly reduced the production of nitric oxygen and inducible nitric oxygen synthase (iNOS) expression, enhanced the expression of heme oxygenase-1, and decreased the phosphorylation of mitogen-activated protein kinases (MAPKs). Arctigenin has anti-inflammatory and antioxidative effects on LPS-induced acute lung injury, which are associated with modulation of MAPK, HO-1, and iNOS signaling.

CXCR4 receptor overexpression in mesenchymal stem cells facilitates treatment of acute lung injury in rats

Novel therapeutic regimens for tissue renewal incorporate mesenchymal stem cells (MSCs) as they differentiate into a variety of cell types and are a stem cell type that is easy to harvest and to expand in vitro. However, surface chemokine receptors, such as CXCR4, which are involved in the mobilization of MSCs, are expressed only on the surface of a small proportion of MSCs, and the lack of CXCR4 expression may underlie the low efficiency of homing of MSCs toward tissue damage, which results in a poor curative effect. Here, a rat CXCR4 expressing lentiviral vector was constructed and introduced into MSCs freshly prepared from rat bone marrow. The influence of CXCR4 expression on migration, proliferation, differentiation, and paracrine effects of MSCs was examined in vitro. The in vivo properties of CXCR4-MSCs were also investigated in a model of acute lung injury in rats induced by lipopolysaccharide. Expression of CXCR4 in MSCs significantly enhanced the chemotactic and paracrine characteristics of the cells in vitro but did not affect self-renewal or differentiation into alveolar and vascular endothelial cells. In vivo, CXCR4 improved MSC homing and colonization of damaged lung tissue, and furthermore, the transplanted CXCR4-MSCs suppressed the development of acute lung injury in part by modulating levels of inflammatory molecules and the neutrophil count. These results indicated that efficient mobilization of MSCs to sites of tissue injury may be due to CXCR4, and therefore, increased expression of CXCR4 may improve their therapeutic potential in the treatment of diseases where tissue damage develops.