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Abstract The pathophysiology of COVID-19-associated coagulopathy is complex and not fully understood. SARS-CoV-2 spike protein (SP) may activate platelets and interact with fibrin(ogen). We aimed to investigate whether isolated SP can be present in clots retrieved in COVID-19 patients with acute ischemic stroke (by mechanical thrombectomy) and myocardial infarction. In this pilot study, we could detect SP, but not nucleocapsid protein, on platelets of COVID-19 patients’ thrombi. In addition, in all three COVID-19 thrombi analyzed for molecular biology, no SARS-CoV-2 RNA could be detected by real-time polymerase chain reaction. These data could support the hypothesis that free SP, besides the whole virus, may be the trigger of platelet activation and clot formation in COVID-19.

Abstract Background The network of intermediate filament proteins underlying the inner nuclear membrane forms the nuclear lamin. A- and B-type lamins are the major components of the nuclear lamina. Lamins function in many nuclear activities. The role of lamin A and transcription factors (NF-kB) as anti-apoptotic is well documented. Recently, lamin A has also been considered as a mechanosensor protein that is able to maintain nuclear integrity from mechanical insults. We aimed to verify how lamin A expression varies in healthy cuff cells and in those with different-sized tears where various mechanical stresses are present. Methods Forty-three patients with rotator cuff tear (RCT) [23M–20F, mean age (SD): 63.5 (6.1)] were enrolled. Tissue samples excised from the most medial point of tear margins were analyzed for lamin A expression by immunohistochemistry. Controls were represented by samples obtained by normal supraspinatus tendons excised from patients submitted to reverse shoulder prosthesis implant [8M–7F, mean age (SD): 67.9 (7.1)]. The intensity of staining was graded, and an H-score was assigned. Statistical analysis was performed. Results Our study revealed a moderate intensity of lamin A in the healthy cuff tendons, a higher expression of this protein in the small tears, and a significant decrease of lamin A with increasing tear size (p