What is the recommended protocol for Platelet-Rich Plasma (PRP) activation?

Platelet-Rich Plasma (PRP) Activation Protocol

The recommended protocol for PRP activation should include either calcium chloride, autologous thrombin, a combination of both, or collagen type I as activating agents, with the choice depending on the specific clinical application and desired release kinetics of growth factors. 1, 2

Blood Collection and Initial Processing

• Collect blood using plastic tubes (not glass) to avoid contact activation 1
• Use appropriate anticoagulants: trisodium citrate (0.109M), ACD, or CPD; NEVER use EDTA as it causes platelet swelling and premature activation 1
• Process blood at room temperature as soon as possible, preferably within 1 hour of collection 1
• For PRP preparation, centrifuge at low force (170-200g) for 10 minutes at room temperature for optimal platelet yield 1

Centrifugation Protocol

• For standard PRP: Use a single low-speed centrifugation (170-200g for 10 minutes) 1
• For platelet-concentrated plasma (PCP): After initial PRP preparation, perform a second centrifugation at >2300g, remove 90% of supernatant plasma, and resuspend platelets 3
• Centrifugation should occur at controlled room temperature to avoid precipitation and cold activation 1

PRP Activation Methods

Common Activation Options:

1. Calcium Chloride (10%)

   • Produces progressive release of growth factors over 24 hours
   • Forms a clot within 15 minutes
   • Provides sustained release of VEGF, PDGF-AB, and TGF-β1 2

2. Autologous Thrombin (10%)

   • Causes immediate release of growth factors that remains stable over time
   • Forms a clot within 15 minutes
   • Suitable when immediate availability of growth factors is desired 2

3. Calcium Chloride + Thrombin Mixture (10%)

   • Combines effects of both activators
   • Forms a clot within 15 minutes
   • Provides immediate and stable release of PDGF and TGF-β1 2

4. Collagen Type I (10%)

   • Does not form a clot
   • Produces lower overall growth factor release
   • May be preferred when clot formation is undesirable 2

5. Temperature-Controlled Activation

   • Novel method without additives
   • Prepare PRP under hypothermic conditions (4°C)
   • Activate by rewarming to 37°C
   • Creates natural fiber scaffolding with slower growth factor release 4

Timing Considerations

• Freshly prepared PRP should be used within 4 hours for optimal results 1
• If activation is performed, the timing depends on the specific application:
  • For immediate growth factor release: use thrombin or calcium chloride/thrombin mixture 2
  • For gradual release over time: use calcium chloride activation 2

Clinical Application Considerations

• In some applications, collagen-rich tissues may activate PRP naturally, eliminating the need for pre-application activation 1
• The activation method significantly affects both the physical form of PRP and the release kinetics of growth factors 2
• Document the activation procedure used, as this is considered an appropriate practice by expert consensus 1

Important Caveats and Pitfalls

• PRP preparations vary widely in content, purity, and biological properties, which impacts clinical efficacy 1
• The concentration of platelets should be at least 2-3 times above baseline for therapeutic effect 5
• Avoid storing PRP at 4°C as cold activation might occur prematurely 1
• If using frozen PRP, thaw samples in a water bath at 37°C for 2-5 minutes (depending on volume) until completely thawed 1
• The choice of activation method should align with the desired release profile of growth factors for the specific clinical application 2