Plasma


Fig. 25.1

Platelet physiology. Platelets are not cells, but rather 1–4 μm anucleated cytoplasmic fragments of megakaryocytes. Platelets contain dense granules and alpha granules. The latter contain adhesion molecules, coagulation and fibrinolytic factors, growth factors, cytokines, antibacterial proteins, and other factors, totaling more than 1000. These factors are released with platelet activation as shown on the schematics. ∗AG – Alpha granules, DG – Dense granules, PDGF – Platelet-derived growth factor, IGF-1 – Insulin-like growth factor-1, TGF-b1 – Transforming growth factor beta-1, CTGF – Connective tissue growth factor, VEGF – Vascular endothelial growth factor, b-FGF – Basic fibroblastic growth factor, EGF – Epidermal growth factor




Table 25.1

Platelet-rich plasma proteins























Biologically active proteins released from platelet-rich plasma and their effects on tissue repair


Platelet-derived growth factor (PDGF) – fibroblast production, chemotaxis, collagen production


Insulin-like growth factor-1 (IGF-1) – cell growth, differentiation


Transforming growth factor beta-1 (TGF-b1) angiogenesis, extracellular matrix formation, cell viability


Connective tissue growth factor (CTGF) – connective tissue growth


Vascular endothelial growth factor (VEGF) – new blood vessel growth and anti-apoptosis of blood vessel cells


Fibroblastic growth factor (b-FGF) – tissue repair, collagen production, myoblast proliferation


Epidermal growth factor (EGF) – cell recruitment, proliferation, differentiation, promotion of epithelial cells




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Fig. 25.2

Typical pattern of healing. An initial reaction to injury starts immediately with hemostasis. The inflammatory phase followed by proliferation and then remodeling. The healing of tissue may last more than a year



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Fig. 25.3

Why use platelet-rich plasma (PRP)? The normal or physiologic platelet concentration in blood is 150–450,00 per μL. It is characteristically three to eight times greater in the PRP. Subsequently, the concentration of growth factors and other signaling molecules is significantly higher, which may potentially explain some of the mechanisms of accelerated tissue regeneration with platelet-rich plasma application. PRP seems to produce simultaneous anti-inflammatory and pro-inflammatory effects, which diverge it from corticosteroids, widely used to hold up inflammatory cascade, and from prolotherapy, which typically aggravates inflammatory reaction after its injection


The mechanisms of effects of PRP on repair are complex but appear to resemble a typical pattern of healing, facilitated with PRP (Figs. 25.2 and 25.3). There are a number of factors, producing impact on its effect, including volume of blood used for PRP preparation, PRP concentration, use of anticoagulant during PRP preparation, platelet count, white blood cell (WBC) count, type of injury or disease, PRP equipment used, number of PRP injections, interval between PRP injections, and many others (Table 25.2). The recent studies suggest that the release of PRP growth factors may be dependent on such remote factors and the microbiota and immune status of the host.





Table 25.2

Factors influencing platelet-rich plasma effect

































Factors affecting PRP injection outcomes


Volume of blood used for PRP preparation


PRP concentration


Use of anticoagulant


Pre-procedure platelet count


WBC count


Type of injury or disease treated with PRP


Equipment used in PRP preparation


Number of PRP injections


Interval between PRP injections


Host microbiota


Host immune status


Others



PRP Platelet-rich plasma

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Oct 20, 2020 | Posted by in ANESTHESIA | Comments Off on Plasma
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