title: Blood components for topical use in tissue regeneration: evaluation of corneal lesions treated with platelet lysate and considerations on repair mechanisms.
abstract: BACKGROUND
  The fields of application of topically administered platelet derivatives are numerous and increasing. The use of this blood component is based on the fact that it contains growth factors and proteins of the clotting system. Studies carried out so far have been aimed at identifying these substances, assaying their content in the various types of platelet concentrate used, determining the in vivo and in vitro mechanisms of action, and trying to standardise the production methods. However, much still remains to be discovered, not only about the growth factors, but also about all those cytokines and biochemical mediators that are involved in the processes of tissue regeneration.
  
  
  METHODS
  We studied the use of platelet lysate, obtained from platelet-rich plasma which had been frozen, for the treatment of corneal ulcers caused by neurotrophic keratitis and of epithelial and stromal loss following physical or chemical trauma. The platelet lysate was administered in the form of eye drops to patients who had not responded to conventional therapy and who were at risk of corneal scarring.
  
  
  RESULTS
  The results were satisfactory in terms of both tissue regeneration and healing time. The clinical follow-up showed a clear reduction in the time of regeneration of the damaged epithelium and stabilisation of the repair process. The epithelial defects disappeared completely in all the treated eyes within 6 to 32 days, with the time depending on the type of lesion and the severity of the damage.
  
  
  CONCLUSIONS
  The cornea reacts to damage by releasing numerous substances, including cytokines, growth factors, proteases and neuropeptides in order to restore its anatomical integrity. A change in the balance between inhibitory and stimulating substances can lead to the development of complications. Fast, correct re-epithelialisation is fundamental for the formation of new, transparent tissue. The use of non-gelified platelet-rich plasma was found to be effective in all cases with loss of epithelium, such as post-herpetic corneal ulcers or ulcers occurring following trauma or exposure to caustic substances.
authors.affiliation: SIMTI ASP., Crotone, Italy. wgsit.crotone@libero.it
authors.forename: Walter
authors.initials: W
authors.lastname: Geremicca
authors.forename: Carla
authors.initials: C
authors.lastname: Fonte
authors.forename: Sisto
authors.initials: S
authors.lastname: Vecchio
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000368:Aged; D001792:Blood Platelets; D002457:Cell Extracts / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D003315:Cornea / Q000502:physiology; D003320:Corneal Ulcer / Q000503:physiopathology / Q000628:therapy*; D019573:Epithelium, Corneal / Q000187:drug effects / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007322:Instillation, Drug; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009883:Ophthalmic Solutions; D012038:Regeneration / Q000187:drug effects*; D012189:Retrospective Studies
chemical_list: D002457:Cell Extracts; D009883:Ophthalmic Solutions
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