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PRP and Growth Factors

By September 12, 2022April 16th, 2024No Comments

Platelet Rich Plasma (PRP) is the processed liquid fraction of autologous blood with the platelet concentration above the baseline found in the circulation. The first reviews of PRP were published in 2006. This review focused on platelet function and mode of action and the effects of PRP on the various stages of the healing cascade. From 2006 to the present, the proven mode of action of PRP has been the platelet derived growth factors that are released from the granules contained on the platelets.

Growth Factors

Growth factors are any of a group of proteins that stimulate the growth of specific tissues. Growth factors play a key role in promoting cellular differentiation and cell division. They are natural proteins in the human body that promote the growth, organization and maintenance of cells and tissues. They act as chemical messengers to stimulate growth, healing and repair.

There are different kinds of growth factors in the human body. Some examples include insulin like growth factor which stimulate growth per growth hormone from the pituitary gland, epidermal growth factor which stimulates the growth of epithelial cells, platelet derived growth factor which stimulates the growth of muscle cells and connective tissues and nerve growth factor which stimulates the growth of neuronal cells.

PRP has gained increasing popularity with the use in basically all medical fields. The scientific rationale for this therapy is that a concentrated platelet, injected into a site of injury, mediates tissue repair via the release of many biologically active growth factors and other substances.

These substances are responsible for initiating the hemostatic cascade, synthesis of new connective tissue and revascularization.

Additionally, plasma proteins (eg. fibrinogen, prothrombin and fibronectin) are present in the platelet poor plasma fraction and can also stimulate the release of growth factors to aid in the healing of injuries and accelerate the injury repair process.

Granules on the Platelets

Three types of granules on platelets (Major Types)

  • Dense Granules
  • Alpha Granules
  • Lysosomes

Alpha Granules are the most abundant and the most important. They are formed in the megakaryocytes and then distributed to the platelets. Studies suggest that hundreds of soluble proteins are released by alpha granules when stimulated

Evidence is now apparent that secreted alpha granule proteins (growth factors) function in coagulation, inflammation, atherosclerosis, antimicrobial host defense, angiogenesis, wound repair and malignancy. The alpha granule can also participate in many opposing activities such as pro and anticoagulants, proteases and their inhibitors and antiangiogenic proteins. Therefore, this activity can be somewhat controlled for a therapeutic benefit.

The growth factors released by the alpha granules that are most seen in tissue repair and regeneration are:

Platelet Derived Growth Factor (PDGF)

  • Derived from Platelets, endothelial cells, macrophages, smooth muscle cells
  • Mitogenic for mesenchymal cells and osteoblasts,
  • Stimulates chemotaxis and mitogenesis in fibroblasts and smooth muscle cells
  • Regulates collagen synthesis
  • Stimulates macrophage and neutrophil chemotaxis

Transforming Growth Factor (TGF-B)

  • Derived from macrophages and T lymphocytes
  • Stimulates undifferentiated mesenchymal cell proliferation
  • Regulates endothelial, fibroblastic and osteoblastic mitogenesis
  • Regulates collagen synthesis
  • Regulates mitogenic effects of other growth factors

Vascular Endothelial Growth Factor (VEGF)

  • Derived from platelets, macrophages, keratinocytes and endothelial cells
  • Increases vascular permeability
  • Stimulates mitogenesis for endothelial cells

Epidermal Growth Factor (EGF)

  • Derived from platelets, macrophages and monocytes
  • Stimulates proliferation of keratinocytes, fibroblasts
  • Stimulates mitogenesis for endothelial cells

Fibroblast Growth Factor (FGF)

  • Derived from Platelets, Macrophages Mesenchymal cells, Chondrocytes and osteoblasts
  • Promotes cells growth and differentiation of chondrocytes and osteoblasts
  • Mitogenic for mesenchymal cells, chondrocytes and osteoblasts

Connective Tissue Growth Factor (CTGF)

  • Derived from platelets and fibroblasts
  • Promotes angiogenesis, cartilage regeneration, fibrosis and platelet adhesion

Insulin Like Growth Factor IGF-1)

  • Derived from platelets, endothelial cells, fibroblasts, osteoblasts
  • Chemotactic for fibroblasts and stimulates protein synthesis
  • Enhances bone formation by proliferation and differentiation of osteoblasts

Hepatocyte Growth Factor (HGF)

  • Derived from platelets and mesenchymal cells
  • Regulates cell growth and motility in epithelial and endothelial cells
  • Supports epithelial repair and neovascularization during wound healing

Keratinocyte Growth Factor (KGF)

  • Derived from fibroblasts and mesenchymal cells
  • Regulates epithelial migration and proliferation

Angiopoietin (Ang-1)

  • Derived from platelets
  • Induces angiogenesis stimulating migration and proliferation of endothelial cells
  • Supports and stabilizes blood vessel development

Platelet Factor 4 (PF-4)

  • Derived from platelets
  • Microbiocidal activities
  • Calls leukocytes and regulates their action

Stromal Cell Derived Factor (SDF-1)

  • Derived from platelets, endothelial cells and fibroblasts
  • Induces proliferation and differentiation into endothelial progenitor cells stimulating angiogenesis
  • Recruits mesenchymal stem cells and leukocytes

Tumor Necrosis Factor (TNF)

  • Derived from macrophages and T lymphocytes
  • Regulates monocyte migration and fibroblast proliferation
  • Stimulates macrophage activation
  • Stimulates angiogenesis

These growth factors, released from the alpha granules on the platelets are the major proteins involved in the repair and regeneration of the wound healing process. They are all contained in Platelet Rich Plasma and Platelet Rich Fibrin.

Juventix Regenerative Medical is an industry leader in the regenerative medical field. Our Platelet Rich Plasma Kits are FDA approved and designed for safety and effectiveness. They are cost effective and very easy to use. Our kits provide consistency of concentrated product when obtained from the same source.

Juventix Regenerative Medical offers a patent pending LED Photo- Activator to activate the platelets and begin the regenerative process. The activation, a critical step in the release of cytokines and growth factors, is accomplished with light and not with the addition of other chemicals such as Calcium Chloride or Thrombin.

Juventix Regenerative Medical supplies a Bio-Incubator that transforms the Platelet Rich Plasma into an Injectable Platelet Rich Fibrin. The PRF, commonly called the “second generation of platelet products, has a broader range of clinical applications while providing outstanding outcomes


Regenerative Regards,


Dr. Robert McGrath



Int J Mol Sci 2020 Oct;21(20):7794  PMID 33096812

Blood Rev 2009 Jul;23(4) 177-189 PMID 19450911


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