title: Stability of Growth Factors in Autologous Serum Eyedrops After Long-Term Storage.
abstract: OBJECTIVE
  The purpose of this study is to assess the stability of the growth factors (GF) in autologous serum eyedrops under different storage conditions.
  
  
  METHODS
  The concentration of epidermal growth factor (EGF), transforming growth factor-β (TGF-β1), platelet-derived growth factor AB (PDGF-AB), and albumin was measured in fresh and defrosted samples of autologous serum under different storage conditions. The fresh and defrosted samples were cooled at 4 °C, and they were studied immediately after preparation, or after defrosting, and after 1, 2, 3, and 4 weeks. The concentration of GF was also assessed after 1, 3, 6, and 9 months at -20 °C. We also investigated how the different storage conditions influence the biological effects of autologous serum on conjunctival and corneal cell cultures.
  
  
  RESULTS
  The concentration of EGF, TGF-β1, PDGF-AB, and albumin remained stable over the 4 weeks at 4 °C, both in fresh and in defrosted samples. Likewise, no statistically significant differences were found between the GF concentration in fresh samples and after 1, 3, 6, and 9 months of freezing at -20 °C. Moreover, no differences were found on the cell proliferation and differentiation between cultured cells with fresh or defrosted samples after 4 weeks at 4 °C or after 1, 3, 6, or 9 months at -20 °C.
  
  
  CONCLUSIONS
  Long-term storage of autologous serum eyedrops at -20 °C does not affect the concentration of GF, simplifies clinical logistics, and reduces the frequency of blood extractions from the patients.
authors: a Ophthalmology Service, Hospital Cruz Roja , Madrid , Spain .
authors: José Santiago
authors: JS
authors: López-García
authors: a Ophthalmology Service, Hospital Cruz Roja , Madrid , Spain .
authors: Isabel
authors: I
authors: García-Lozano
authors: b Dry Eye Unit, Research Laboratory , Ophthalmology Service, Hospital Ramón y Cajal , Madrid , Spain .
authors: Luis
authors: L
authors: Rivas
authors: c Ophthalmology Service, Hospital Infanta Sofia , Madrid , Spain , and.
authors: Nuria
authors: N
authors: Ramírez
authors: d Clinical Analysis School, Pharmacy College, Complutense University of Madrid , Madrid , Spain.
authors: Maria T
authors: MT
authors: Méndez
authors: d Clinical Analysis School, Pharmacy College, Complutense University of Madrid , Madrid , Spain.
authors: Rafaela
authors: R
authors: Raposo
mesh_terms: D000328:Adult; D000418:Albumins / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology; D002478:Cells, Cultured; D003228:Conjunctiva / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015925:Cryopreservation; D004355:Drug Stability; D004356:Drug Storage; D004797:Enzyme-Linked Immunosorbent Assay; D004815:Epidermal Growth Factor / Q000097:blood*; D064368:Healthy Volunteers; D006801:Humans; D053539:Keratin-19 / Q000378:metabolism; D053558:Keratin-3 / Q000378:metabolism; D016850:Limbus Corneae / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008875:Middle Aged; D009883:Ophthalmic Solutions / Q000737:chemistry* / Q000494:pharmacology; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D044967:Serum / Q000737:chemistry* / Q000502:physiology; D053773:Transforming Growth Factor beta1 / Q000097:blood*
chemical_list: D000418:Albumins; D053539:Keratin-19; D053558:Keratin-3; D009883:Ophthalmic Solutions; D010982:Platelet-Derived Growth Factor; D053773:Transforming Growth Factor beta1; C095477:platelet-derived growth factor AB; D004815:Epidermal Growth Factor
keywords: Autologous serum eyedrops; conjunctival culture cells; corneal culture cells; epitheliotrophic growth factors; long-term storage; sodium hyaluronate