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Related Concept Videos

Formation of the Platelet Plug01:22

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The platelet phase, the second stage of hemostasis, commences around 15-20 seconds after an injury. It follows and overlaps with the vascular phase, during which blood vessels constrict to minimize blood loss.
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
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After a fibrin clot is formed, the next step is clot retraction, a vital process facilitated by platelet contractile proteins, such as actin and myosin. These proteins pull the fibrin strands closer together and condense the clot. This action reduces the size of the clot, creating a smaller, denser structure that effectively seals off the damaged vessel. Clot retraction consolidates the clot and helps with wound healing by bringing the edges of the damaged blood vessel closer together.
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Structure and Function of Platelets01:18

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The cell fragments known as platelets are disc-shaped, with an average diameter of about 3 μm and a thickness of roughly 1 μm. They play a crucial role in the body's vascular clotting system, which also involves plasma proteins, blood cells, and blood vessel tissues.
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Hemostasis is a crucial process that prevents excessive blood loss from damaged blood vessels. It involves various mechanisms such as vasoconstriction, platelet adhesion and activation, and fibrin formation. The importance of each mechanism depends on the type of vessel injury. In contrast, thrombosis is the abnormal formation of a blood clot within the blood vessels, leading to potential complications if the clot obstructs blood flow. Thrombosis can be caused by increased coagulability of the...
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Antiplatelet Drugs: Prostaglandin Synthesis, P2Y12 and Glycoprotein IIb/IIIa Inhibitors01:20

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Antiplatelet drugs emerge as frontline defenders against the insidious threat of thromboembolic diseases, where abnormal clots obstruct vital blood vessels. These drugs stand as bulwarks, inhibiting platelet aggregation and clot formation, thereby mitigating the risk of life-threatening conditions like myocardial infarction, coronary artery disease, and thrombotic strokes.
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Related Experiment Video

Updated: May 6, 2026

Effects of Allogeneic Platelet-Rich Plasma PRP on the Healing Process of Sectioned Achilles Tendons of Rats: A Methodological Description
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Effects of Allogeneic Platelet-Rich Plasma PRP on the Healing Process of Sectioned Achilles Tendons of Rats: A Methodological Description

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Increasing platelet concentrations in leukocyte-reduced platelet-rich plasma decrease collagen gene synthesis in

Stacie G Boswell1, Lauren V Schnabel, Hussni O Mohammed

  • 1Lisa A. Fortier, Cornell University, VMC C3-181, Ithaca, NY 14853. laf4@cornell.edu.

The American Journal of Sports Medicine
|October 19, 2013
PubMed
Summary
This summary is machine-generated.

Minimizing leukocytes in platelet-rich plasma (PRP) is more crucial than maximizing platelet concentration for tendon healing. High platelet levels in leukocyte-reduced PRP (lrPRP) can decrease collagen synthesis, indicating reduced tendon metabolism.

Keywords:
growth factorplateletplatelet-rich plasmatendon

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Related Experiment Videos

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Effects of Allogeneic Platelet-Rich Plasma PRP on the Healing Process of Sectioned Achilles Tendons of Rats: A Methodological Description
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Area of Science:

  • Biomedical Engineering
  • Orthopedics
  • Regenerative Medicine

Background:

  • Platelet-rich plasma (PRP) is widely used for treating tendinopathy.
  • Optimal platelet and leukocyte combinations in PRP preparations remain unclear.
  • Leukocyte-reduced PRP (lrPRP) may have a plateau effect where higher platelet concentrations become detrimental.

Purpose of the Study:

  • To investigate the effect of varying platelet:leukocyte ratios in lrPRP on tendon extracellular matrix synthesis.
  • To determine the optimal concentration of platelets in lrPRP for tendon healing.

Main Methods:

  • Controlled laboratory study using equine superficial digital flexor tendon explants.
  • Cultured tendon explants in different lrPRP formulations for 96 hours.
  • Analyzed growth factor and cytokine concentrations (PDGF-BB, TNF-α, TGF-β1, IL-1β) and gene expression (COL1A1, COL3A1, MMP-3, MMP-13, COMP, IL-1β).

Main Results:

  • Anabolic factors (PDGF-BB, TGF-β1) increased with platelet concentration in lrPRP.
  • Catabolic cytokine (IL-1β) decreased with increasing platelet concentration.
  • Higher platelet concentrations in lrPRP significantly reduced collagen type I and III (COL1A1, COL3A1) synthesis in tendons.

Conclusions:

  • Reducing leukocytes in PRP is more important than maximizing platelets for decreasing inflammation and enhancing matrix gene synthesis.
  • A threshold exists for platelet concentration in lrPRP; beyond this, further increases do not enhance anabolic signaling.
  • Further in vivo and in vitro studies are needed to define the ideal PRP composition for tendinopathy treatment.