Morphological and Mechanical Characterization of Extracellular Vesicles and Parent Human Synoviocytes under Physiological and Inflammatory Conditions

Causal influences of osteoarthritis on COVID-19: a Mendelian randomization study

Objective

Although observational and genetic studies have indicated a correlation between OA and COVID-19, it remains uncertain whether osteoarthritis (OA) contributes to the severity of COVID-19. Here, we aimed to investigate the potential causal links between the two.

Methods

In this study, we conducted Mendelian randomization (MR) analysis to investigate whether there is a potential causal connection between OA and COVID-19 outcomes. The analysis utilized publicly available GWAS summary datasets, incorporating data on OA (N = 455,221), SARS-CoV-2 infection (N = 2,597,856), hospitalized COVID-19 (N = 2,095,324), and critical COVID-19 (N = 1,086,211). Additionally, we performed a literature analysis to establish a molecular network connecting OA and COVID-19.

Results

The MR analysis showed causal effects of OA on hospitalized COVID-19 (OR: 1.21, 95% CI: 1.02-1.43, p = 0.026) and critical COVID-19 (OR: 1.35, 95% CI: 1.09-1.68, p = 0.006) but not on SARS-CoV-2 infection as such (OR: 1.00, 95% CI: 0.92-1.08, p = 0.969). Moreover, the literature-based pathway analysis uncovered a set of specific genes, such as CALCA, ACE, SIRT1, TNF, IL6, CCL2, and others, that were found to mediate the association between OA and COVID-19.

Conclusion

Our findings indicate that OA elevates the risk of severe COVID-19. Therefore, larger efforts should be made in the prevention of COVID-19 in OA patients.

Multilevel Assessment of Stent-Induced Inflammation in the Adjacent Vascular Tissue

A recent U.S. Food and Drug Administration report presented the currently available scientific information related to biological response to metal implants. In this work, a multilevel approach was employed to assess the implant-induced and biocorrosion-related inflammation in the adjacent vascular tissue using a mouse stent implantation model. The implications of biocorrosion on peri-implant tissue were assessed at the macroscopic level via in vivo imaging and histomorphology. Elevated matrix metalloproteinase activity, colocalized with the site of implantation, and histological staining indicated that stent surface condition and implantation time affect the inflammatory response and subsequent formation and extent of neointima. Hematological measurements also demonstrated that accumulated metal particle contamination in blood samples from corroded-stetted mice causes a stronger immune response. At the cellular level, the stent-induced alterations in the nanostructure, cytoskeleton, and mechanical properties of circulating lymphocytes were investigated. It was found that cells from corroded-stented samples exhibited higher stiffness, in terms of Young's modulus values, compared to noncorroded and sham-stented samples. Nanomechanical modifications were also accompanied by cellular remodeling, through alterations in cell morphology and stress (F-actin) fiber characteristics. Our analysis indicates that surface wear and elevated metal particle contamination, prompted by corroded stents, may contribute to the inflammatory response and the multifactorial process of in-stent restenosis. The results also suggest that circulating lymphocytes could be a novel nanomechanical biomarker for peri-implant tissue inflammation and possibly the early stage of in-stent restenosis. Large-scale studies are warranted to further investigate these findings.

Effects of pro-inflammatory cytokines and cell interactions on cell area and cytoskeleton of rheumatoid arthritis synoviocytes and immune cells

Rheumatoid synovitis is infiltrated by immune cells that interact with synoviocytes, leading to the pannus formation. Inflammation or cell interaction effects are mainly evaluated with cytokine production, cell proliferation or migration. Few studies interest on cell morphology. Here, the purpose was to deepen some morphological changes of synoviocytes or immune cells under inflammatory conditions. Inflammatory cytokines, IL-17 and TNF that are largely involved in RA pathogenesis, induced a change in synoviocyte morphology, inducing a retracted cell with higher number of pseudopodia. Several morphological parameters decreased in inflammatory conditions: cell confluence, area and motility speed. The same impact on cell morphology was observed in co-culture of synoviocytes and immune cells in inflammatory/non-inflammatory conditions or with cell activation (miming the in vivo situation), affecting both cell types: synoviocytes were retracted and inversely immune cells proliferated, indicating that cell activation induced a morphological change of cells. In contrast, with RA but not control synoviocytes, cell interactions were not sufficient to affect PBMC and synoviocyte morphology. The morphological effect came only from the inflammatory environment. These findings reveal that the inflammatory environment or cell interactions induced massive changes in control synoviocytes, with cell retraction and increase of pseudopodia number, leading to better interactions with other cells. Except in the case of RA, the inflammatory environment was absolutely required for such changes.