In the last three decades, there have been significant developments in cellular and molecular biology that have enhanced our comprehension of the intricate mechanisms involved in the process of healing and repair. The mechanisms are regulated by fascinating pathways that include a variety of signaling molecules. PRP (platelet-rich plasma) is an intriguing innovation that can significantly enhance the healing process and has therefore become increasingly popular in regenerative and cosmetic medicine, as well as several surgical specialties like dentistry, orthopedics, otolaryngology, cardiovascular surgery, and maxillofacial surgery.

What is PRP? How Does It Work?

PRP is a volume of plasma containing a platelet count significantly above the baseline value of whole blood. It classically has two components – the plasma and the platelets - which are together associated with the clotting mechanism and the release of various bioactive molecules. The concentration of platelets in PRP is at least 2.5–8 times higher than the number of platelets in whole venous blood, which is 150000–450000 platelets per µL.

Preparation of PRP

The preparation of PRP can involve several techniques, both manual and mechanical, and the resulting quality and quantity of PRP may vary depending on the starting concentration. However, all protocols involve standard steps, such as collecting blood, separating red blood cells and concentrating platelets by centrifugation, and activating the sample using a platelet agonist. Conflicting results exist regarding the correlation between GF content and platelet counts in PRP, possibly due to patient variables or differences in processing, handling, storing, and assays used.

Platelets are the first to arrive at the wound site as they are recruited by damaged collagen and therefore have the most crucial role in wound healing. Platelets aggregate within 10 minutes after coming in direct contact with damaged collagen from injured vessels or the basement membrane of tissue, leading to the degranulation of α-granules. Platelet degranulation releases a myriad of growth factors like platelet-derived GF (PDGF), transforming GF-β1 (TGF-β1), vascular endothelial GF (VEGF), basic fibroblastic GF (bFGF), and epidermal GF (EGF). Among the growth factors secreted, PDGF and TGF-β1 have the most significant impact on healing and impart regenerative benefits to PRP.

PDGF stimulates cell replication of important stem cells for fibroblasts and endothelial cells, increases the budding of new capillaries, stimulates the production of fibronectin, and promotes wound contraction and remodeling. TGF-β contributes in the production of collagen and fibronectin by cells, while inhibiting collagen degradation by decreasing proteases and increasing protease inhibitors, all of which favor fibrogenesis. Additionally, PDGF and TGF-β can influence other cellular processes, including stem cell recruitment, cellular migration, collagen synthesis, and proliferation.

APPLICATIONS

Platelet-rich plasma finds applications in healing wrinkled and damaged skin, rejuvenating scars and wounds, regenerating musculoskeletal tissues, promoting hair growth on the scalp, and aiding cosmetic enhancement. PRP has been found to be effective in stimulating hair follicles, resulting in increased hair count, hair growth, and hair thickness in both men and women, making it a valuable option for hair loss treatment. Scientific studies have shown that PRP can reduce inflammation by inhibiting cytokine secretion, leading to improved healing and regeneration of injured tissues. Therefore, PRP can be a useful treatment option for long-standing scars.  

Furthermore, PRP is a valuable prospect for achieving optimal healing outcomes in various surgical procedures, such as mandibular reconstruction, alveolar clefts, treatment of periodontal pockets, and osseointegrated implants. In such procedures, the adhesiveness of PRP enables easier graft manipulation, leading to improved flap adaptation and hemostasis, consequently resulting in an optimal seal as opposed to that attained with primary closure alone.

ADVANTAGES

While the majority of GFs are released within the first hour, the distinctive feature of Platelet-rich plasma is the extended-release GFs, which may be seen throughout the platelet viability period, i.e., up to 7 days. Using PRP is a way to expedite the body's natural healing mechanisms. PRP is a cost-effective and non-invasive treatment option that provides quick results without significant side effects. It promotes tissue healing and regeneration without the risk of immune system reactions. Therefore, it is an ideal choice for people who are looking for natural options to meet their aesthetic and regenerative needs. As research continues, PRP is expected to become an increasingly essential part of aesthetic and regenerative medicine in the future.

Uses in Dentistry: Platelet-rich plasma plays a crucial role in regenerative dentistry, facilitating the preservation of the vitality of the pulp-dentin complex, particularly in teeth with immature apices. It also enables continued root development in traumatized teeth when used for suitable cases. Its distinctive properties extend beyond the field of endodontics, benefiting procedures such as mandibular reconstruction, alveolar cleft repair, periodontal defect treatment, periodontal plastic surgery, healing of periapical lesions or cysts, and implant placement. By enhancing the healing process, PRP is additionally utilized in apical surgery, the treatment of infrabony defects, and implant surgery, ensuring predictable and optimal outcomes for the improved oral health of the patients.

REFERENCES

1. Samadi P., Sheykhhasan M., and Khoshinani HM. The Use of Platelet-Rich Plasma in Aesthetic and Regenerative Medicine: A Comprehensive Review. Aesthetic Plast Surg. 2019 Jun;43(3):803–814.

2. Dhurat R., Sukesh M. (2014). Principles and methods of preparation of platelet-rich plasma: a review and author’s perspective. J Cutan Aesthet Surg 7(4):189.

3. Fareed WM et al. (2017), Efficacy of Blood and its Products: A Boon for Oral Surgeons. J Univers Surg 5(1):1–7.

4. Kumaran MS (2014): Platelet-rich plasma in dermatology: a boon or a bane? Indian J Dermatol Venereol Leprol 80(1):58.

5. Gentile P et al. (2018): Mechanical and controlled PRP injections in patients affected by androgenetic alopecia JoVE 131:e56406

6. Etulain J et al (2018) An optimized protocol for platelet-rich plasma preparation to improve its angiogenic and regenerative properties. Sci Rep 8(1):1513.

7. Carter MJ, Fylling CP, and Parnell LK (2011). Use of platelet-rich plasma gel on wound healing: a systematic review and metaanalysis. Eplasty 11:e38.

8. Albanese A, Licata ME, Polizzi B, and Campisi G. Platelet-rich plasma (PRP) in dental and oral surgery: from wound healing to bone regeneration Immun Aging. 2013 Jun 13;10(1):23.

9. Carlson NE, Roach RB Jr., Platelet-rich plasma: clinical applications in dentistry J Am Dent Assoc. 2002 Oct;133(10):1383-6.

10. Arnoczky SP, Sheibani-Rad S. The basic science of platelet-rich plasma (PRP): what clinicians need to know. Sports Med Arthrosc Rev. 2013;21(4):180–5.

11. Cole BJ, Seroyer ST, Filardo G, Bajaj S, and Fortier LA. Platelet-rich plasma: where are we now and where are we going? Sports Health. 2010;2(3):203-1