title: Releasing growth factors from activated human platelets after chitosan stimulation: a possible bio-material for platelet-rich plasma preparation.
abstract: BACKGROUND
  Thrombin is commonly used for activating the platelets and releasing the growth factors on the application of platelet-rich plasma (PRP). We have previously reported that chitosan can enhance rabbit platelet aggregation. In this study, the effects of chitosan on the subsequent growth factors release after human platelets activation were examined to evaluate the possibility of chitosan being used as a substitute for thrombin during PRP preparation.
  
  
  METHODS
  Human platelet activation was determined by aggregation, adhesion and alpha-granule membrane glycoprotein expression. Platelet aggregation was measured by the turbidimetric method, the adhesion was directly examined on chitosan-coated glass plates under light microscope and scanning electron microscope (SEM), and the alpha-granule membrane glycoprotein was detected by fluorescent isothiocyanate (FITC)-conjugated anti-CD61 antibody through flow cytometry. The subsequent epidermal growth factor (EGF), platelet-derived growth factor (PDGF)-AB and transforming growth factor (TGF)-beta1 release from platelets were assayed by ELISA after mixing with chitosan.
  
  
  RESULTS
  The enhancing effects on the platelet adhesion and the aggregation from chitosan were observed. Under both microscopes, the adhesive platelets on the chitosan-coated plates were not only greater in number but also earlier in activation than those on the control plates. With flow cytometry, increased glycoprotein IIIa expression in platelets was detected after chitosan treatment. Greater concentrations of growth factors were measured from PRP after chitosan treatment than after the solvent treatment.
  
  
  CONCLUSIONS
  Because of the observations of growth factors releasing from activated human platelets after chitosan stimulation, we suggest that chitosan may be an appropriate substitute for thrombin in PRP preparation.
authors.affiliation: Department of Periodontology, School of Dentistry, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan.
authors.forename: E-Chin
authors.initials: EC
authors.lastname: Shen
authors.forename: Tz-Chong
authors.initials: TC
authors.lastname: Chou
authors.forename: Ching-Hwa
authors.initials: CH
authors.lastname: Gau
authors.forename: Hsiao-Pei
authors.initials: HP
authors.lastname: Tu
authors.forename: Yen-Teen
authors.initials: YT
authors.lastname: Chen
authors.forename: Earl
authors.initials: E
authors.lastname: Fu
mesh_terms: D001672:Biocompatible Materials / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D048271:Chitosan / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000032:analysis; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D006490:Hemostatics / Q000494:pharmacology*; D006801:Humans; D039661:Integrin beta3 / Q000032:analysis; D036341:Intercellular Signaling Peptides and Proteins / Q000493:pharmacokinetics*; D008562:Membrane Glycoproteins / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D010949:Plasma; D015539:Platelet Activation / Q000187:drug effects; D010973:Platelet Adhesiveness / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects; D010976:Platelet Count; D010982:Platelet-Derived Growth Factor / Q000032:analysis; D013917:Thrombin / Q000494:pharmacology; D053773:Transforming Growth Factor beta1 / Q000032:analysis
chemical_list: D001672:Biocompatible Materials; D005456:Fluorescent Dyes; D006490:Hemostatics; D039661:Integrin beta3; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D010982:Platelet-Derived Growth Factor; D053773:Transforming Growth Factor beta1; C095477:platelet-derived growth factor AB; D004815:Epidermal Growth Factor; D048271:Chitosan; D013917:Thrombin; D016650:Fluorescein-5-isothiocyanate