Microparticle concentration can increase in some diseases with an increased thrombotic risk. Some patients suffer from venous thromboembolism in spite of thrombocytopenia. It is possible to measure microparticles concentration in patients with thrombocytopenia?
Most of circulating microparticles are of platelet origin (80%). However, the 20% left is represented by those of red cell, leukocyte and endothelial origin. So, you can have microvesicles from other cells. Also if you have a consumption coagulopathy you may hace MVs from activated and consumed platelets.
They are small phospholipid vesicles released by various activated or stimulated cells in particular blood cells. They contain part of protein derived from their parent cells membrane protein. Platelets release them under high sheer stress or complement attack. These MPs have a role in cell to cell interaction, cell signalling and may also be involved in transferring receptors between different types of cells. From haemostasis point of view more commonly implicated in HIT, TTP, CVD, sepsis and diabetes to name a few. I am not sure if the mechanism of their production is clearly understood yet however there is plenty of work in literature around their mode of action.
The most frequently described characteristics of both in vitro and in vivo MPs is their procoagulant activity . The importance of MPs in hemostasis is demonstrated dramatically by findings in patients with Scott syndrome, a severe bleeding disorder in which MP formation is defective. In this syndrome, markedly reduced MP counts result from abnormal activity of the enzyme scramblase, which mediates membrane expression of phosphatidylserine and formation of MPs . In contrast to the lack of MPs in patients with Scott syndrome, elevated numbers of PMPs occur during acute bleeding episodes associated with hemophilia and idiopathic thrombocytopenic purpura. This increase could represent a compensatory mechanism, possibly resulting from defective coagulation . Several methods for analysis of MPs have been reported. Flow-cytometry , enzyme-linked immunosorbent assay (ELISA) are the most widely adopted. However several groups have used different approaches to basic procedures such as centrifugation, re-suspension and washing of the MP pellet, making direct comparison of results difficult. Furthermore, the cell lineage markers adopted are broadly different .
My question was not about structure or founction of microparticles but I am looking for explanation why the enzyme-linked immunosorbent assay (ELISA) for microparticles does not work in patients with thrombocytopenia.
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