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What are platelet microparticles?

What are platelet microparticles?

Platelet microparticles (PMPs) are platelet membrane microvesicles that form spontaneously during platelet storage. They have also been identified in fresh frozen plasma and cryoprecipitate. PMPs are strongly procoagulant and retain many of the biological properties of intact platelets.

How do endothelial cells communicate with platelets?

From a mechanistic standpoint, platelets and endothelial cells communicate on multiple levels. Cross-talk may occur over a distance (paracrine signaling), via transient interactions (so-called give-and-go mechanism), or through receptor-mediated cell-cell adhesion.

Do platelets stick to endothelial cells?

Because activated, but not resting, platelets have been shown to adhere to intact endothelium, it has been suggested that platelet thrombi may also occur in the absence of endothelial cell denudation, particularly in the microvasculature (2–5).

What prevents platelets from binding to endothelial cells?

vWF, a multidomain protein that forms large disulfide-linked multimers, is secreted from endothelial cells in a latent form that is unable to bind platelets.

What prevents platelets from sticking to endothelial cells?

The integrity of the endothelial lining provides a barrier preventing platelet adhesion to subendothelial substrates, and focal removal of endothelium (denudation) has long been studied as a mechanism of platelet adhesion to vascular walls.

What is the role of vitamin C in maintaining vascular integrity?

The endothelial cells lining blood vessels form a tight barrier, which is weakened (permeabilized) by inflammation. Vitamin C tightens the endothelial barrier and maintains its integrity during inflammation, but the mechanisms for vitamin C action remain unclear.

What happens during platelet aggregation?

Platelet aggregation and thrombosis are the key phenomena in atherosclerosis and CVD. Platelets stick to the damaged vessel wall to form a plaque, and then stick to each other (aggregate) and release adenosine diphosphate (ADP) and thromboxane A2 (TXA2), which promote further aggregation.

How are microparticles released from the endothelial cells?

Microparticles from endothelial cells, platelets and leukocytes are released into the circulation, at which point the stabilizing interaction of pericytes with the endothelium becomes disrupted and pericytes produce proteases that damage the endothelial basement membrane.

What happens to endothelial microparticles during vascular injury?

During vascular injury, microparticles derived from endothelium may contain tissue factor and activate coagulation. Specifically, in tumor necrosis factor alpha (TNF-α), lipopolysaccharide or oxidized LDL, an increased endothelial microparticle release containing tissue factor has been described [19,20].

How are endothelial microparticles ( EMPs ) generated in HUVEC?

Endothelial microparticles (EMPs) were reported to be generated following the appearance of blebs on the surface of HUVEC after stimulation with tumor necrosis factor alpha [102].

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