Ch 4: PRP

Question 1

What to the alpha particles of platelets contain?

Answer 1

Hundreds of growth factors, cytokines, vasoactive peptides, extracellular matrix proteins

Released upon platelet activation and are critically important in all phases of wound healing

Question 2

What should the platelet concentration of PRP be in comparison to peripheral blood?

Answer 2

At least 3-5 times higher

Question 3

What else does PRP contain?

Answer 3

• Clotting factors
• Plasma proteins
• antibacterial and fungicidal effects
• membrane glycoproteins which influence inflammation
• 800 unique proteins

Depending on preparation method, also potential for leukocyte isolation to occur resulting in leukocyte- and platelet-rick plasma (L-PRP)

Question 4

How does PRP act?

Answer 4

Increases the proliferation of mesenchymal stem cells and fibroblasts in a dose-dependant manner. TGF-B within PRP increases collagen type 1 production in tendons

Question 5

How is PRP osteopromotive?

Chondropromotive?

Answer 5

• Stimulates the production of osteoclast-like cells
• Platelets contain a number of grwoth factors to initiate bone healing - PDGF, TGF-B, VEGF, BMP

Chondro:
- Significant increased in chondrocyte proliferation and celular accumulation of GAGs and collagen tpe 2 in porcine chondrocytes with platelet lysate

Question 6

How do you prepare PRP?

Answer 6

Classic 2-step centrifugation method:

• 10-110ml whole blood
• anticoagulant
• soft spin
• plasma and uppermost layer of buffy coat transferred
• second, longer hard spin
• Majority of platelet-poor plasma is discarded and the pellet is resuspended forming PRP

If you use the entire buffy coat, will get L-PRP

Gravity-filtration method
- 60ml anticoagulated blood in reservoir bag mixed with sterile water leading to platelet swelling
- Passed through a filter
- platelets, erythrocytes and some leukocytes captures
- Sterile saline flushed back through to filter resulting in leukocyte- and platelet-rick preparation (but NOT plasma)

Question 7

List 2 contraindications of PRP treatment

Answer 7

• Thrombocytopaenia
• Coagulation defects