The role of the lectin pathway of the complement system in SARS-CoV-2 lung injury

Although some evidence showed the activation of complement systems in COVID-19 patients, proinflammatory status and lectin pathway remain unclear. Thus, the present study aimed to demonstrate the role of MBL and ficolin-3 in the complement system activation and compared to pandemic Influenza A virus H1N1 subtype infection (H1N1pdm09) and control patients. A total of 27 lungs formalin-fixed paraffin-embedded samples (10 from H1N1 group, 6 from the COVID-19 group, and 11 from the control group) were analyzed by immunohistochemistry using anti-IL-6, TNF-alfa, CD163, MBL e FCN3 antibodies. Genotyping of target polymorphisms in the MBL2 gene was performed by real-time PCR. Proinflammatory cytokines such as IL-6 and TNF-alpha presented higher tissue expression in the COVID-19 group compared to H1N1 and control groups. The same results were observed for ICAM-1 tissue expression. Increased expression of the FCN3 was observed in the COVID-19 group and H1N1 group compared to the control group. The MBL tissue expression was higher in the COVID-19 group compared to H1N1 and control groups. The genotypes AA for rs180040 (G/A), GG for rs1800451 (G/A) and CC for rs5030737 (T/C) showed a higher prevalence in the COVID-19 group. The intense activation of the lectin pathway, with particular emphasis on the MBL pathway, together with endothelial dysfunction and a massive proinflammatory cytokines production, possibly lead to a worse outcome in patients infected with SARS-Cov-2. Moreover, 3 SNPs of our study presented genotypes that might be correlated with high MBL tissue expression in the COVID-19 pulmonary samples.

Effects of analgesic use on inflammation and hematology in a murine model of venous thrombosis

Venous thrombosis (VT) is a significant cause of morbidity and mortality in humans. Surgical animal models are crucial in studies investigating the pathogenesis of this disease and evaluating VT therapies. Because inflammation is critical to both the development and resolution of VT, analgesic medications have the potential to adversely affect multiple parameters of interest in VT research. The objective of this study was to determine how several common analgesics affect key variables in a murine ligation model of deep vein thrombosis. Male C57BL/6 mice were randomly assigned to receive either local (bupivacaine) or systemic parenteral analgesia (buprenorphine, tramadol, or carprofen) or 0.9% NaCl (control). All mice underwent laparotomy and ligation of the inferior vena cava, and treatment was continued until euthanasia at 6 or 48 h after surgery. Analysis of harvested tissues and blood included: hematology, thrombus weight, serum and vein-wall cytokines (IL1β, IL6, IL10, TNFα), soluble P-selectin, and vein-wall leukocyte infiltration. Compared with 0.9% NaCl, all of the analgesics affected multiple parameters important to VT research. Carprofen and tramadol affected the most parameters and should not be used in murine models of VT. Although they affected fewer parameters, a single dose of bupivacaine increased thrombus weight at 6 h, and buprenorphine was associated with reduced vein wall macrophages at 48 h. Although we cannot recommend the use of any of the evaluated analgesic dosages in this mouse model of VT, buprenorphine merits additional investigation to ensure the highest level of laboratory animal care and welfare.