The case of complement activation in COVID-19 multiorgan impact
Authors: Noris, Marina; Benigni, Ariela; Remuzzi, Giuseppe
The novel coronavirus disease COVID-19 originates in the lungs, but it may extend to other organs, causing, in severe cases, multiorgan damage, including cardiac injury and acute kidney injury. In severe cases, the presence of kidney injury is associated with increased risk of death, highlighting the relevance of this organ as a target of SARS-CoV-2 infection. COVID-19-associated tissue injury is not primarily mediated by viral infection, but rather is a result of the inflammatory host immune response, which drives hypercytokinemia and aggressive inflammation that affect lung parenchymal cells, diminishing oxygen uptake, but also endothelial cells, resulting in endotheliitis and thrombotic events and intravascular coagulation. The complement system represents the first response of the host immune system to SARS-CoV-2 infection, but there is growing evidence that unrestrained activation of complement induced by the virus in the lungs and other organs plays a major role in acute and chronic inflammation, endothelial cell dysfunction, thrombus formation, and intravascular coagulation, and ultimately contributes to multiple organ failure and death. In this review, we discuss the relative role of the different complement activation products in the pathogenesis of COVID-19-associated tissue inflammation and thrombosis and propose the hypothesis that blockade of the terminal complement pathway may represent a potential therapeutic option for the prevention and treatment of lung and multiorgan damage.
Mechanical, dielectric, and thermal properties of fluorosilicone rubber composites filled with silica/multiwall carbon nanotube hybrid fillers
JOURNAL OF APPLIED POLYMER SCIENCE
Authors: Tan, Changbin; Liu, Guangliang; Yao, Hao; Li, Xiangyang; Li, Gen; Qing, Long; Yang, Yan
In this work, hybrid fillers consist of modified silica (SiO2) and multiwalled carbon nanotube (MWCNT) were used to improve the mechanical, dielectric, and thermal properties of fluorosilicone (FSR) composites via a direct mechanical mixing method. With the increase of CNT loading in SiO2/CNT hybrid loading ratio, the tensile properties, dielectric constant, electrical conductivity, and thermal properties all increase without a sharp sacrifice of flexibility. The dielectric constant of FSR-S15/C5 achieved 7,370 @1 kHz, which is about four orders of the FSR-S20, and the dielectric loss remains as low as 0.676 @1 kHz. Therefore, the linkage of SiO(2)and FSR chains not only enhances the interfacial interaction between the fillers and FSR matrix but also decreases the agglomeration of the fillers in matrix. What is more, modified SiO(2)and CNT were designed as the effective hybrid filler to improve the performance of the polymeric matrix through synergic effect.