The influence of platelet-derived products on angiogenesis and tissue repair: a concise update

Abstract

Platelet degranulation allows the release of a large amount of soluble mediators, is an essential step for wound healing initiation, and stimulates clotting, and angiogenesis. The latter process is one of the most critical biological events observed during tissue repair, increasing the growth of blood vessels in the maturing wound. Angiogenesis requires the action of a variety of growth factors that act in an appropriate physiological ratio to assure functional blood vessel restoration. Platelets release main regulators of angiogenesis: Vascular Endothelial Growth Factors (VEGFs), basic fibroblast growth factor (FGF-2), and Platelet derived growth factors (PDGFs), among others. In order to stimulate tissue repair, platelet derived fractions have been used as an autologous source of growth factors and biomolecules, namely Platelet Rich Plasma (PRP), Platelet Poor Plasma (PPP), and Platelet Rich Fibrin (PRF). The continuous release of these growth factors has been proposed to promote angiogenesis both in vitro and in vivo. Considering the existence of clinical trials currently evaluating the efficacy of autologous PRP, the present review analyses fundamental questions regarding the putative role of platelet derived fractions as regulators of angiogenesis and evaluates the possible clinical implications of these formulations.

The Role of TGF Beta 1 and PDGF BB in Wound Healing of the Palate

“…Leukocyte count of these samples is lower than the whole blood percentage. After its activation with calcium chloride or thrombin, this preparation can be used as a liquid solution or as a gel [10]. …”

“…Following activation, L-PRP might be used either as a liquid solution or in an activated gel form. Among the commercial systems available are Harvest Smart-PreP (Harvest Technologies, Plymouth, MA, USA), Biomet GPS III (Biomet Inc., Warsaw, IN, USA), Plateltex (Prague, Czech Republic), and Regen PRP (RegenLab, Le Mont-sur-Lausanne, Switzerland) [10].…”

Platelet-Rich Fibrin and Its Usage in Orthopaedic Surgery: Review

“…Gerçekleştirilen pek çok çalışmada, sistemik hormonlar ve büyüme faktörlerinin sert ve yumuşak doku metabolizması üzerine olan etkileri araş-tırılmıştır. 12,13 Büyüme faktörlerinin, özellikle yara iyileşmesi sürecindeki proliferasyon, diferansiyasyon, kemotaksis ve morfogenez gibi hücresel olayların düzenlenmesinde önemi bulunmaktadır. 14 Sitokinler ile büyüme faktörleri; hücre büyümesi, çoğalması, farklılaşması, sekresyonu ve rezorpsiyonunu etkileyerek kemik ve doku rejenerasyonunu stimüle eder.…”

Platelet-mimetic strategies for modulating the wound environment and inflammatory responses

“…10,[20][21][22][23] Tissue inflammation and healing are further modulated by protease-activated receptors (PARs) found on platelet surfaces; these PARs stimulate the release of alpha granules, which contain various growth factors and angiogenic factors that aid in tissue repair. 24,25 Many glycoproteins found on the platelet surface membrane, such as CD55 and CD59, are a part of the complement system, which eliminates particulate invaders by providing recognition mechanisms for phagocytes that can then clear invaders from the body via phagocytosis. 4 Other glycoprotein receptors on the platelet surface membrane, such as (GP)IIb-IIIa, GPIba, FcgRIIa, and toll-like receptors (TLRs), are triggered when bacteria bind to the platelet surface; these receptors, in turn, induce the secretion of antimicrobial peptides known as platelet microbicidal proteins, which mediate chemotaxis of phagocytes, and cause the platelet to shift from a quiescent to an activated state.…”