What is Platelet-Rich Plasma (PRP)?
An Advanced Overview for Medical Practitioners
Biological Basis of PRP
Platelet-Rich Plasma (PRP) is an autologous biologic product derived from the patient’s own whole blood. It contains a supraphysiological concentration of platelets suspended in plasma, enriched with growth factors, cytokines, and extracellular vesicles that modulate inflammation, stimulate cellular proliferation, and enhance tissue regeneration.
The average baseline platelet count in human peripheral blood is ~200,000 ± 75,000/µL. In whole blood, platelets remain in a quiescent state, with an in vivo half-life of approximately 7–10 days. Upon activation by exposure to collagen, thrombin, or calcium ions, platelets release their intracellular alpha and dense granule contents in a controlled, sequenced manner.
Key Bioactive Constituents of PRP
Most of PRP’s regenerative capacity is mediated by molecules stored in platelet alpha granules, including:
Upon activation, over 95% of platelet-stored growth factors are released within 10 minutes, initiating a cascade of biological events essential for soft tissue repair and regeneration.
The Phases of PRP-Mediated Healing
PRP accelerates and enhances the body’s intrinsic healing cascade, particularly in poorly vascularised tissues. The three primary overlapping phases are:
1. Inflammation (Days 1–3)
Platelet degranulation triggers clot formation and release of pro-inflammatory cytokines
Neutrophil and macrophage recruitment facilitates debridement and release of further mediators (IL-1β, TNF-α, MCP-1)
Dense granules release ADP, serotonin, and calcium to promote platelet aggregation and vascular constriction
2. Proliferation (Days 3–21)
Proliferation and migration of fibroblasts, endothelial cells, and keratinocytes
Type III collagen deposition
Neoangiogenesis via VEGF, FGF, and TGF-β signalling
Epithelialisation and granulation tissue development
3. Remodelling (Weeks to Months)
Type III collagen is replaced with Type I
Matrix metalloproteinases (MMPs) and tissue inhibitors (TIMPs) regulate ECM turnover
Vascular maturation and functional restoration of tissue
The Importance of Platelet Concentration
The regenerative efficacy of PRP is directly correlated with the dose of functional platelets delivered to the target tissue. Therapeutic PRP must meet or exceed baseline platelet counts to elicit a clinically relevant biological effect.
Alocuro Evidence-Based Targets:
Aesthetic applications: 3–5× baseline concentration
Orthopaedics/MSK: 6–9× baseline
Surgical/wound healing: varies by application and tissue type
However, many commercial PRP kits:
Achieve only ~2× baseline platelet concentration due to plasma dilution
Recover only ~60% of total platelets
Include residual red blood cells and neutrophils, which may exacerbate inflammation
PRP Clinical Applications – Mechanisms & Context
Musculoskeletal Medicine
PRP improves tendon matrix organisation and fibroblast proliferation
Reduces IL-6 and TNF-α expression in osteoarthritic joints
Increases hyaluronic acid synthesis and modulates chondrocyte phenotype
Common sites: rotator cuff, lateral epicondyle, patellar tendon, Achilles tendon, plantar fascia, intra-articular joints
Aesthetic & Dermatology
Enhances dermal fibroblast activity and ECM production
Modulates melanogenesis, aiding in pigmentation control
Induces angiogenesis in hypoperfused skin regions
Supports follicular cell proliferation in androgenetic alopecia and hypotrichosis
Wound Care
Increases VEGF and angiopoietin-1 expression
Accelerates epithelial closure and granulation tissue formation
Reduces microbial load through leukocyte-derived antimicrobial peptides
Surgical Use
Promotes haemostasis via thrombin-mediated clot reinforcement
Reduces incidence of post-operative seroma and infection
Enhances graft integration and suture line healing
Why Clinicians Choose Alocuro
Consistent concentration and yield across patients
Customisable protocols for LP-PRP and LR-PRP
ARTG-listed with full practitioner support
Scalable across aesthetic, musculoskeletal, and surgical practices
Ongoing education and clinical case consultation provided