Chapter 4: PRP

Question 1

What do 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 (besides platelets) does PRP contain?

Answer 3

• Clotting factors
• Plasma 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-dependent 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 growth factors to initiate bone healing: PDGF, TGF-B, VEGF, BMP

Chondro:
- Significant increase in chondrocyte proliferation and cellular accumulation of GAGs and collagen type 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-rich preparation (but NOT plasma)

Question 7

What are 2 contraindications to PRP treatment?

Answer 7

• Thrombocytopenia
• Coagulation defects

Question 8

What is autologous conditioned sera?

Answer 8

Whole blood is injected into a chamber with borosilicate beads and allowed to coagulate -> incubate 6-24 hr -> leukocytes will adhere to the beads and produce IL-1ra and other anti-inflammatory cytokines
You centrifuge it to collect the serum
Then give as an intraarticular injection for OA

No good canine evidence

Question 9

What are some (4) current study findings for PRP in dogs?

Answer 9

• owners found it better than steroid/HA injections for elbows
• CCLR autograft with PRP did better on force plate than control solution
• Single joint OA may improve with a single PRP injection
• Helped ultrasonographic appearance but not gait analysis for supraspinatus tendon