title: Impact of local anaesthetics and needle calibres used for painless PRP injections on platelet functionality.
abstract: The platelet-rich plasma (PRP) is an autologous biotherapy commonly used for its healing properties. Once activated, platelets released a real "cocktail" of growth factor and cytokines implied in numerous regenerative processes. However the impact of medical practices associated to PRP therapeutic use on platelets functionality remains poorly known.
  
  
  OBJECTIVE
  we evaluated the in vitro effects of two commonly used local anesthetics (Xylocaine(*) and Naropin(*)) on PRP functionality. We also investigated the quantity and quality of PRP that passed through the smallest gauge needle commercialized.
  
  
  METHODS
  PRP from 9 healthy volunteers were prepared using our previously described home made purification protocol. Platelet aggregation capacity was evaluated by aggregometry assays and the growth factor release was determined by ELISA after platelet activation. We also evaluated the platelet activation status, reactivity and stability of platelets by flow cytometry using the P-selectin expression marker.
  
  
  RESULTS
  the association of local anaesthetics with PRP injections resulted in a significant decrease of platelets functionality, assessed by their capacity of aggregating. Local anaesthetics did not interfere with the growth factor release. The different needle sizes and calibres tested for PRP injections did not influence the platelet functionality.
  
  
  CONCLUSIONS
  the use of local anaesthetics to prevent pain during PRP injections could compromise the therapeutic potential of PRP. These results suggest using carefully local anaesthetics or limiting their use as often is possible. To minimize injection pain, we recommend using 30 G needles. These data will lead to clinical recommendations for painless and controlled PRP injections.
authors.affiliation: Culture and Therapy Unit, Assistance Publique des Hôpitaux de Marseille, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Bausset
authors.affiliation: Culture and Therapy Unit, Assistance Publique des Hôpitaux de Marseille, France.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Magalon
authors.affiliation: Culture and Therapy Unit, Assistance Publique des Hôpitaux de Marseille, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Giraudo
authors.affiliation: Orthopaedic Surgery Unit, CHU La Conception, Assistance Publique des Hôpitaux de Marseille, France.
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Louis
authors.affiliation: Department of Plastic and Reconstructive Surgery, CHU La Conception, Assistance Publique des Hôpitaux de Marseille, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Serratrice
authors.affiliation: Faculty of Pharmacy, Inserm UMR-S1076, Marseille, France.
authors.forename: Corrine
authors.initials: C
authors.lastname: Frere
authors.affiliation: Department of Plastic and Reconstructive Surgery, CHU La Conception, Assistance Publique des Hôpitaux de Marseille, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Magalon
authors.affiliation: Culture and Therapy Unit, Assistance Publique des Hôpitaux de Marseille, France ; Faculty of Pharmacy, Inserm UMR-S1076, Marseille, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Dignat-George
authors.affiliation: Culture and Therapy Unit, Assistance Publique des Hôpitaux de Marseille, France ; Faculty of Pharmacy, Inserm UMR-S1076, Marseille, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Sabatier
keywords: PRP; Platelet concentrate local anaesthetics; growth factors; platelet-rich plasma; regenerative medicine; sport medicine; tendinopathy