On the Correspondence of Diseases Showing Microparticles, Fibrinaloid Microclots and Disorders of the Microcirculation

Cell-derived microparticles with an equivalent diameter below ~1 μm have been observed in a wide spectrum of chronic inflammatory diseases, many of which also present with overlapping comorbidities. These same disorders consistently show microcirculatory disturbances—detectable by nailfold capillaroscopy, laser Doppler techniques, laser speckle imaging or thermal perfusion mapping, and, where measured, the presence of amyloid-containing fibrinaloid microclots ranging from 1–200 μm. Although both microparticles and fibrinaloid microclots have been independently described in numerous conditions, their systematic correspondence has not previously been synthesised. In this commentary, we highlight how the co-occurrence of microparticles and fibrinaloid microclots reflects a shared pathophysiological axis involving endothelial injury, thrombo-inflammation and persistent protein misfolding. We outline the conceptual links underlying this pattern and argue that combined measurement of microparticles and fibrinaloid microclots could offer new diagnostic and mechanistic insights across chronic inflammatory diseases.