Chen Yao Su

In vitro release of growth factors from platelet-rich fibrin (PRF): a proposal to optimize the clinical applications of PRF.

OBJECTIVE Determine the release of growth factors (GF) from platelet-rich fibrin (PRF) and supernatant serum to optimize clinical use. STUDY DESIGN Platelet-derived growth factors-AB (PDGF-AB), transforming growth factor-beta1 (TGF-beta1), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and insulin-like growth factor-1 (IGF-1) were quantified in PRF releasate and in the supernatant serum (N = 8) over 300 minutes after clot formation. Protein profiles were determined by SDS-PAGE. RESULTS Mean quantity of PDGF-AB, TGF-ss1, VEGF, and EGF in PRF releasate increased significantly to about 52, 72, 1, and 3 ng, respectively, whereas mean IGF-1 content remained at 250 ng. GF was also found in serum supernatant. Protein profiles of the releasates and the supernatant serum were similar. CONCLUSION The PRF membrane should be used immediately after formation to maximize release of GF to the surgical site. The remaining fluid can be recovered as an additional source of GF for grafting.

Quantitative assessment of the kinetics of growth factors release from platelet gel

BACKGROUND: The time course of the release of growth factors from platelet (PLT) gels has not been thoroughly studied and should be elucidated for a better standardization of the clinical use of these products.

Antimicrobial activity of platelet (PLT)-poor plasma, PLT-rich plasma, PLT gel, and solvent/detergent-treated PLT lysate biomaterials against wound bacteria

BACKGROUND: Platelet (PLT) gels exhibit antimicrobial activity useful for wound healing. The nature of the antibacterial component(s) is unknown.

Solvent/detergent treatment of platelet concentrates enhances the release of growth factors.

BACKGROUND: Platelet (PLT) growth factors released by thrombin activation of autologous PLT concentrates (PCs) are used in clinics as PLT gels or releasates for tissue repair and wound healing applications. If allogeneic products are to be used for clinical or cell culture applications, a method of viral inactivation of the PC source of growth factors is desirable.

A virally inactivated functional growth factor preparation from human platelet concentrates

Background  Human platelet growth factors (HPGF) are essential for tissue regeneration and may replace fetal bovine serum (FBS) in cell therapy. No method for the manufacture of standardized virally inactivated HPGF has been developed yet.

Human blood-derived fibrin releasates: composition and use for the culture of cell lines and human primary cells.

We have evaluated the capacity of two human blood fractions to substitute for FBS as growth medium supplement for human and animal cell cultures. Non-anticoagulated blood from volunteer donors (N = 13) was centrifuged to isolate a supernatant serum (SS) and a platelet-rich fibrin (PRF) clot which was squeezed to extract the releasate (PRFR). Both materials were characterized for the content in PDGF-AB, TGF-β1, VEGF, bFGF, EGF, IGF, total protein, albumin, IgG, IgM IgA, fibrinogen, cholesterol, triglycerides, various chemistry analytes and hemoglobin. Cell growth promoting activity of pooled SS and PRFR at 1, 5, and 10% in growth medium was evaluated over 7 days using human (HEK293, MG-63) and animal (SIRC, 3T3) cell lines and two human primary cultures (gingival fibroblasts and periodontal ligaments). Viable cell count was compared to that in cultures in FBS free-medium and 10% FBS supplement. SS and PRFR at 1-10% stimulated cell growth significantly more than FBS-free medium and in a way similar to 10% FBS in all cultures apart from 3T3. These two human blood-derived fibrin releasates are equally efficient to substitute for FBS as supplement for cell cultures and could be useful for specialized applications in regenerative medicine, dentistry and oral implantology, or cell therapy.

A novel virally inactivated human platelet lysate preparation rich in TGF-β, EGF and IGF, and depleted of PDGF and VEGF

There is emerging interest in the use of standardized virally inactivated human platelet lysate preparations rich in GFs (growth factors) for cell cultures, cell therapy and clinical applications. In the present paper, we report a simple process to prepare a virally inactivated platelet lysate preparation rich in TGF‐β1 (transforming growth factor‐β1), EGF (epidermal growth factor) and IGF (insulin‐like growth factor) and depleted of PDGF (platelet‐derived growth factor) and VEGF (vascular endothelial growth factor). Apheresis platelet concentrates were treated by the S/D (solvent/detergent) viral inactivation procedure, then subjected to an oil extraction followed by adsorption with activated charcoal and finally sterile‐filtered. The resulting preparation contained a mean of 368.4, 2.4 and 54.7 ng/ml of TGF‐β1, EGF and IGF respectively. PDGF‐AB and VEGF were essentially completely removed by the charcoal treatment. The mean albumin, IgG, IgM and IgA and fibrinogen contents were approx. 40.0, 8.5, 0.87, 1.66 and 2.65 mg/ml respectively, cholesterol and triglycerides were at 15 and 20.7 mg/ml respectively and TnBP (tri‐n‐butyl phosphate) and Triton X‐45 were at 8.7 and 8.8 p.p.m. respectively. Supplementing MEM (minimum essential medium) with 1–10% of this S/D‐treated platelet lysate promoted the proliferation of MG63 and SIRC cell lines as well as, or better than, 10% (v/v) FBS (fetal bovine serum), as based on the MTS [3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium] assay. The process used to prepare such S/D‐treated platelet lysates is easily scalable for industrial production. Our results open up the possibility to evaluate the potential of this new preparation for stem cell expansion and/or bone tissue engineering and regeneration.

Human platelet concentrates: a source of solvent/detergent-treated highly enriched brain-derived neurotrophic factor

BACKGROUND: Human blood platelets (PLTs) contain brain‐derived neurotrophic factor (BDNF), a neurotrophin that binds to neurotrophic tropomyosin‐related kinase B (TrkB) receptor on central nervous system cells. This binding promotes neural synaptic plasticity and memory and prevents neuronal degeneration. Alterations in BDNF homeostasis are associated with aging and are found in several neurodegenerative conditions such as Alzheimers, Huntingtons, and Parkinsons diseases and multiple sclerosis. We have developed PLT viral inactivation and chromatographic fractionation processes and decided here to identify fractions enriched in BDNF.

Blood-derived biomaterials: fibrin sealant, platelet gel and platelet fibrin glue

Blood‐derived biomaterials include fibrin sealant (FS) (also called fibrin glue), platelet gel (PG), and platelet fibrin glue. They are used in many surgical fields because of their functional properties and unique physical advantages compared to synthetic products. FS can be made industrially by the fractionation of large plasma pools, or from single plasma donations. Thanks to a high content in fibrinogen, FS exhibits, after activation by thrombin and formation of a strong fibrin clot, tissue sealing and haemostatic properties. PG and platelet fibrin glue are made from single blood donations (platelet concentrates combined or not with cryoprecipitate). Owing to their richness in platelet, PG and PFG can release, upon thrombin activation, a myriad of growth factors that can stimulate cell growth and differentiation, generating much interest for hard and soft tissues regeneration and healing, as well as, increasingly, cell therapy protocols to replace fetal bovine serum. Blood‐derived biomaterials have the advantages, over synthetic glues and other biomaterials, of being physiologically compatible with human tissues, and of not inducing tissue necrosis or other tissue reactions. They can be readily colonized by cells and are totally biodegradable in a matter of days to weeks. These blood‐derived biomaterials are used increasingly as tissue engineering tools, allowing surgeons to influence and improve the in vitro or in vivo cellular environment to enhance the success of tissue grafting. We review here the three main types of biomaterials that can be made from human blood and describe their biochemical and physiological properties as well as their clinical applications.

A virally inactivated platelet-derived growth factor/vascular endothelial growth factor concentrate fractionated from human platelets

BACKGROUND: Human platelet concentrates (PCs) may be a source material to produce purified growth factors (GFs) for clinical use or cell therapy. However, no fractionation process of therapeutic‐grade GF from PCs has ever been developed.