Use of Platelet-Rich Plasma (PRP) in Regenerative Therapies

Video 1.  Platelet Rich Plasma (PRP) for Facial Rejuvenation and Hair Growth (YouTube link)

Platelet-Rich Plasma (PRP) treatment is one of the most cutting-edge and potentially beneficial types of prolotherapy available today.

What's Prolotherapy

Prolotherapy is short for "proliferation therapy", which can be described as follows:

• Is an alternative medicine practice
• Is a nonsurgical treatment which stimulates healing
• Is also known as regenerative (injection) therapy
• Works by stimulating the body's own natural healing mechanisms to repair injured musculoskeletal, skin or connective tissues

Types of Prolotherapy include:

• Dextrose Prolotherapy
• Platelet Rich Plasma Prolotherapy
• Biocellular Prolotherapy

In this article, we will focus on the use of PRP in regenerative medicine.

Use of PRP in Regenerative Therapies

Regenerative therapy uses a patient's own tissues to initiate the healing process. With PRP, it uses our platelet-rich plasma to initiate the healing in different treatments:

• Topical treatment^[13-16]
• Orthopedic treatment^{[6,27,29-31,33-34,36,39]}
• Periodontal treatment^[28]
• Cosmetic treatment^[11,12]
• Fill (Face, Breast, Gynecologic, Urologic, etc)
• Skin Rejuvenation
• Hair Restoration^[11,43]
• Wound Healing (post-laser, surgery, etc)
• Skin graft healing

Video 2.  Platlett Rich Plasma Therapy (YouTube link)

Growth Factors Released from PRP

Platelets constitute a reservoir of critical growth factors (GFs) and cytokines which may govern and regulate the tissue healing process. The bioactive molecules secreted by platelet α-granules are involved in several cellular activities such as stem cell trafficking, proliferation, and differentiation, with a complex effect on pro/anti-inflammatory and anabolic/catabolic processes.^[26]

Moreover, with respect to purified individual GFs, platelets have the theoretical advantage of containing various bioactive molecules with a natural balance of anabolic and catabolic functions, possibly optimizing the tissue environment and favoring the healing process.^[26]

Based on this rationale, PRP is an easy, low-cost, and minimally invasive procedure to deliver high concentrations of autologous GFs and cytokines into injured tissues in physiological proportions. This blood-derived product, placed directly into the damaged tissue, either surgically or through injections, has been widely experimented in different fields of medicine.^[27-34]

A variety of growth factors can be released from PRP, which could include:^[11,12]

• PDGF (Platelet derived growth factor) 
• Cell Growth, new generation and repair of blood vessels, collagen production 
• FGF (Fibroblast Growth Factor) 
• Tissue repair, cell growth, collagen production, hyaluronic acid production 
• EGF (Epithelial Growth Factor) 
• Promotion of epithelial cell growth, angiogenesis, promotion of wound healing 
• VEGF (Vascular Endothelial Growth Factor) 
• Growth and new generation of vascular endothelial cells 
• TGF-β (Transforming Growth Factor Beta) 
• Growth and neogenesis of epithelial cells and vascular endothelial cells, promotion of wound healing

Harvesting Platelets

Figure 1.  Developments in the production of platelets from stem cells 

Platelets are very rare as they take up only 0.4% of our blood cells. With the process of PRP harvesting, we can concentrate those platelets in plasma, which we then put platelet-rich plasma in the areas that need regeneration and rejuvenation. Below are the steps of harvesting PRP:

1. Collecting blood 
• Read the companion article "Heath Effects of Iron Overload and Benefits of Blood Donation"
2. Separating the platelets 
• By using a centrifuge with proprietary tubes 
• Separate the contents of our blood from the plasma and the platelets. Among the platelets, which areas are higher concentration or lower concentration 
3. Extracting platelet-rich plasma

There are different techniques that can be used in the process:^[11,12]

• One spin technique
• Two spin technique
• Platelet rich fibrin matrix^[23]

Activating Platelets

Among the several variables affecting PRP  lysates (or releasates), platelet activation is a crucial step that might influence the availability of bioactive molecules and therefore tissue healing.^[35-36]

The term “activation” refers to 2 key processes that are initiated during PRP preparation:

1. Degranulation of platelets to release GFs from α-granules
2. Fibrinogen cleavage to initiate matrix formation
• A clotting process which allows the formation of a platelet gel, and therefore to confine the secretion of molecules to the chosen site^.[26]

In our body, platelets will be activated by the injuries or surgeries. Outside our body, platelets can be exogenously activated by:

• CaCl2 (or Calcium Gluconate)
• Thrombin
• Or a mixture of the above

An activation step before PRP administration is included in many of the protocols used, commonly by adding thrombin and/or calcium chloride (CaCl2), but some physicians prefer to inject PRP in its resting form, relying on the spontaneous platelet activation occurring after exposure to the native collagen present in the connective tissues.^[37]

References

1. 6 Major PRP Treatment Benefits, Including for Pain, Injury & Arthritis
2. Platelet-Rich Plasma (PRP) AAOS
3. Dr PRP USA
4. Platlett Rich Plasma Therapy
5. Harvest® SmartPrep® Multicellular Processing System
6. Platelet-Rich Plasma: Pain Relief for Knee OA (Cleveland Clinic)
7. Efficacy of Intra-articular Platelet-Rich Plasma Injections in Knee Osteoarthritis: A Systematic Review
8. The anti-inflammatory and matrix restorative mechanisms of platelet-rich plasma in osteoarthritis
9. PRP & Stem Cell Injections
10. These Injections Can Help Your Chronic Muscle and Joint Pain
11. Platelet Rich Plasma (PRP) for Facial Rejuvenation and Hair Growth - Dr. Vishad Nabili | UCLAMDCHAT
12. To Fill or Not to Fill: Aesthetic Surgery of the Aging Midface | UCLAMDCHAT Webinars
13. Sanchez-Avila, R.M., et al., Treatment of patients with neurotrophic keratitis stages 2 and 3 with plasma rich in growth factors (PRGF-Endoret) eye-drops. Int Ophthalmol, 2017.
14. Anitua, E., et al., PRGF exerts more potent proliferative and anti-inflammatory effects than autologous serum on a cell culture inflammatory model. Exp Eye Res, 2016. 151: p. 115-21.
15. Merayo-Lloves, J., et al., Autologous Plasma Rich in Growth Factors Eyedrops in Refractory Cases of Ocular Surface Disorders. Ophthalmic Res, 2015. 55(2): p. 53-61.
16. Alio, J.L., A.E. Rodriguez, and D. WrobelDudzinska, Eye platelet-rich plasma in the treatment of ocular surface disorders. Curr Opin Ophthalmol, 2015. 26(4): p. 325-32.
17. Burnouf, P.A., et al., A novel virally inactivated human platelet lysate preparation rich in TGF-beta, EGF and IGF, and depleted of PDGF and VEGF. Biotechnol Appl Biochem, 2010. 56(4): p. 151-60.
18. Burnouf, T., et al., A virally inactivated platelet-derived growth factor/vascular endothelial growth factor concentrate fractionated from human platelets. Transfusion, 2010. 50(8): p. 1702-11.
19. Burnouf, T., et al., Human blood-derived fibrin releasates: composition and use for the culture of cell lines and human primary cells. Biologicals, 2012. 40(1): p. 21-30.
20. Burnouf, T., et al., Solvent/detergent treatment of platelet concentrates enhances the release of growth factors. Transfusion, 2008. 48(6): p. 1090-8.
21. Shih, D.T., et al., Expansion of adipose tissue mesenchymal stromal progenitors in serum-free medium supplemented with virally inactivated allogeneic human platelet lysate. Transfusion, 2011. 51(4): p. 770-8.
22. Su, C.Y., et al., Quantitative assessment of the kinetics of growth factors release from platelet gel. Transfusion, 2008. 48(11): p. 2414-20.
23. Su, C.Y., et al., In vitro release of growth factors from platelet-rich fibrin (PRF): a proposal to optimize the clinical applications of PRF. Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 2009. 108(1): p. 56-61.
24. Platelet-Rich Plasma: The Choice of Activation Method Affects the Release of Bioactive Molecules
• TGF, PDGF, and VEGF release kinetics according to the activation method
25. A. S. Wasterlain, H. J. Braun, and J. L. Dragoo, “Contents and formulations of platelet-rich plasma,” Operative Techniques in Orthopaedics, vol. 22, no. 1, pp. 33–42, 2012. 
26. M. Tschon, M. Fini, R. Giardino et al., “Lights and shadows concerning platelet products for musculoskeletal regeneration,” Frontiers in Bioscience-Elite, vol. 3, no. 1, pp. 96–107, 2011. 
• When talking about PLTs and their products, a great number of variables have to be considered. 
• These variables are mainly related to PRP preparation methods, the type of activators, intra- and inter-species variability, types of pathology to be treated, the ways and times of administration and the association of PRP or PG with other treatments. 
27. L. Andriolo, B. Di Matteo, E. Kon, G. Filardo, G. Venieri, and M. Marcacci, “PRP augmentation for ACL reconstruction,” BioMed Research International, vol. 2015, Article ID 371746, 15 pages, 2015.
28. M. Del Fabbro, G. Gallesio, and M. Mozzati, “Autologous platelet concentrates for bisphosphonate-related osteonecrosis of the jaw treatment and prevention. A systematic review of the literature,” European Journal of Cancer, vol. 51, no. 1, pp. 62–74, 2015. 
29. G. Filardo, E. Kon, A. Roffi, B. Di Matteo, M. L. Merli, and M. Marcacci, “Platelet-rich plasma: why intra-articular? A systematic review of preclinical studies and clinical evidence on PRP for joint degeneration,” Knee Surgery, Sports Traumatology, Arthroscopy, vol. 23, no. 9, pp. 2459–2474, 2015. 
30. E. Lopez-Vidriero, K. A. Goulding, D. A. Simon, M. Sanchez, and D. H. Johnson, “The use of platelet-rich plasma in arthroscopy and sports medicine: optimizing the healing environment,” Arthroscopy, vol. 26, no. 2, pp. 269–278, 2010. 
31. A. Roffi, G. Filardo, E. Kon, and M. Marcacci, “Does PRP enhance bone integration with grafts, graft substitutes, or implants? A systematic review,” 
32. J. A. Textor, J. W. Norris, and F. Tablin, “Effects of preparation method, shear force, and exposure to collagen on release of growth factors from equine platelet-rich plasma,” American Journal of Veterinary Research, vol. 72, no. 2, pp. 271–278, 2011. 
33. F. Vannini, B. Di Matteo, G. Filardo, E. Kon, M. Marcacci, and S. Giannini, “Platelet-rich plasma for foot and ankle pathologies: a systematic review,” Foot and Ankle Surgery, vol. 20, no. 1, pp. 2–9, 2014. 
34. Y. Zhu, M. Yuan, H. Y. Meng et al., “Basic science and clinical application of platelet-rich plasma for cartilage defects and osteoarthritis: a review,” Osteoarthritis and Cartilage, vol. 21, no. 11, pp. 1627–1637, 2013. 
35. T. E. Foster, B. L. Puskas, B. R. Mandelbaum, M. B. Gerhardt, and S. A. Rodeo, “Platelet-rich plasma: from basic science to clinical applications,” The American Journal of Sports Medicine, vol. 37, no. 11, pp. 2259–2272, 2009. 
36. B. Di Matteo, G. Filardo, E. Kon, and M. Marcacci, “Platelet-rich plasma: evidence for the treatment of patellar and Achilles tendinopathy—a systematic review,” Musculoskeletal Surgery, vol. 99, no. 1, pp. 1–9, 2015.
37. Heath Effects of Iron Overload and Benefits of Blood Donation (Travel to Health)
38. Regenerative medicine: Current therapies and future directions
39. Schnabel LV, Mohammed HO, Miller BJ, McDermott WG, Jacobson MS, Santangelo KS, Fortier LA (2007) Platelet rich plasma (PRP) enhances anabolic gene expression patterns in flexor digitorum superficialis tendons. J Orthop Res 25(2):230–240
40. Editorial Commentary: The Promise of Platelet-Rich Plasma
• On the basis of this most recent Level I evidence review, PRP results in “significant clinical improvements” in patients with symptomatic osteoarthritis of the knee.
41. Campbell, K.A., Saltzman, B.M., Mascarenhas, R. et al. Does intra-articular platelet-rich plasma injection provide clinically superior outcomes compared with other therapies in the treatment of knee osteoarthritis? A systematic review of overlapping meta-analyses. Arthroscopy. 2015; 31: 2213–2221
42. Autologous serum eye drops reduce ocular surface disease symptoms
43. Hair Loss Got You Down? Platelet-Rich Plasma May Regrow It
44. Inhibiting Platelet Activation with Garlic & Onions
45. Researchers find drug that enables healing without scarring
46. Regenerative eyedrops tap blood for tears
47. REGENERATIVE MEDICINE THERAPEUTIC SUITES (Mayo Clinic)
48. Developments in the production of platelets from stem cells