Fig. 4: More amyloid-containing deposits in skeletal muscle, but not located inside capillaries or lymphatic vessels.
From: Muscle abnormalities worsen after post-exertional malaise in long COVID
A Typical example of amyloid-containing deposits in skeletal muscle. Pre-SARS-CoV-2 pandemic skeletal muscle sections stained with Thioflavin T showed similar levels of amyloid-containing deposits as healthy controls. B The concentration of amyloid-containing deposits in skeletal muscle in long COVID patients (n = 24) was higher (Group: p < 0.001) than in healthy controls (n = 21) and increased in long COVID patients and healthy controls upon exercise (Time: p = 0.008). C Amyloid-containing deposits were not found inside endothelial cells, but rather next to endothelial cells, or in the extracellular matrix between fibers. We performed the amyloid stainings on all patients and show a typical example in the figures. D Amyloid-containing deposits were not located inside lymphatic vessels. Continuous parametric longitudinal data (panel B) were analyzed with a generalized linear mixed model with a two-sided ANOVA. Bar: 100 μm. PEM post-exertional malaise. Box plots show the median (centerline), the first and third quartiles (the lower and upper bound of the box), and the whiskers show the 1.5× interquartile range. Source data are provided in the Source Data File.
