Biomechanical Issues of Mechanical Ventilation in Covid-19 Therapy / 医用生物力学

The critically ill coronavirus disease 2019 (Covid-19) patients usually present acute respiratory distress syndrome (ARDS), or even acute respiratory failure, and require mechanical ventilation (MV) to provide support for breathing. However, clinical studies have found an extraordinarily high mortality rate (>50%) for those Covid-19 patients who underwent MV. Considering the mechanical nature of MV, the high mortality rate is highly possible to be associated with mechanical stretch-induced lung injury during MV. Thus, it is imperative to understand the MV-induced pathological alterations in the respiratory system and corresponding mitigation measures in order to improve the therapy of critically ill Covid-19 patients. Ventilator-induced lung injury in therapy of critically ill Covid-19 patients involves several biomechanical factors and mechanisms, including changes in respiratory parameters, inflammatory cytokines storm, ciliary-mucus system, airway smooth muscle cells, lung fibrosis, and stretch-activated cell signaling. It is hoped that these biomechanical issues can be diligently investigated, so as to provide insights for optimizing the therapy for Covid-19 as well as other respiratory diseases.

Effect of sanguinarine on biomechanics of rat airway smooth muscle cells / 生物医学工程学杂志

This study aimed to evaluate the effect of sanguinarine on biomechanical properties of rat airway smooth muscle cells (rASMCs) including stiffness, traction force and cytoskeletal stress fiber organization. To do so, rASMCs cultured were treated with sanguinarine solution at different concentrations (0.005~5 μmol/L) for 12 h, 24 h, 36 h, and 48 h, respectively. Subsequently, the cells were tested for their viability, stiffness, traction force, migration and microfilament distribution by using methylthiazolyldiphenyl-tetrazolium bromide assay, optical magnetic twisting cytometry, Fourier transform traction microscopy, scratch wound healing method, and immunofluorescence microscopy, respectively. The results showed that at concentration below 0.5 μmol/L sanguinarine had no effect on cell viability, but caused dose and time dependent effect on cell biomechanics. Specifically, rASMCs treated with sanguinarine at 0.05 μmol/L and 0.5 μmol/L for 12 and 24 h exhibited significant reduction in stiffness, traction force and migration speed, together with disorganization of the cytoskeletal stress fibers. Considering the essential role of airway smooth muscle cells (ASMCs) biomechanics in the airway hyperresponsiveness (AHR) of asthma, these findings suggest that sanguinarine may ameliorate AHR via alteration of ASMCs biomechanical properties, thus providing a novel approach for asthma drug development.