Extracellular vesicles derived from M2-like macrophages alleviate acute lung injury in a miR-709-mediated manner.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is characterised by an uncontrolled inflammatory response, and current treatment strategies have limited efficacy. Although the protective effect of M2-like macrophages (M2φ) and their extracellular vesicles (EVs) has been well-documented in other inflammatory diseases, the role of M2φ-derived EVs (M2φ-EVs) in the pathogenesis of ALI/ARDS remains poorly understood. The present study utilised a mouse model of lipopolysaccharide-induced ALI to first demonstrate a decrease in endogenous M2-like alveolar macrophage-derived EVs. And then, intratracheal instillation of exogenous M2φ-EVs from the mouse alveolar macrophage cell line (MH-S) primarily led to a take up by alveolar macrophages, resulting in reduced lung inflammation and injury. Mechanistically, the M2φ-EVs effectively suppressed the pyroptosis of alveolar macrophages and inhibited the release of excessive cytokines such as IL-6, TNF-α and IL-1ß both in vivo and in vitro, which were closely related to NF-κB/NLRP3 signalling pathway inhibition. Of note, the protective effect of M2φ-EVs was partly mediated by miR-709, as evidenced by the inhibition of miR-709 expression in M2φ-EVs mitigated their protective effect against lipopolysaccharide-induced ALI in mice. In addition, we found that the expression of miR-709 in EVs derived from bronchoalveolar lavage fluid was correlated negatively with disease severity in ARDS patients, indicating its potential as a marker for ARDS severity. Altogether, our study revealed that M2φ-EVs played a protective role in the pathogenesis of ALI/ARDS, partly mediated by miR-709, offering a potential strategy for assessing disease severity and treating ALI/ARDS.

Autologous Platelet-Rich Plasmapheresis in Cardiovascular Surgery: A Narrative Review.

Perioperative coagulopathy and bleeding are common complications in cardiovascular surgery with cardiopulmonary bypass and result in an increased rate of allogeneic blood transfusion. Both bleeding and transfusion can increase postoperative mortality and morbidity. Patient blood management can significantly reduce allogeneic blood transfusions, improve clinical outcomes, and conserve blood resources; however, measures to protect platelets from destruction by cardiopulmonary bypass still are lacking. As an unusual method of autologous blood transfusion, autologous platelet-rich plasmapheresis can effectively protect platelets from damage and has been used successfully in cardiovascular surgery. This narrative review aims to address some major clinical applications and debates of using autologous platelet-rich plasmapheresis in cardiovascular surgery. In addition, this review summarizes the application of autologous platelet gel, a product developed from autologous platelet-rich plasma, in cardiac surgery.