title: Tyrosine phosphorylation of vitreous inflammatory and angiogenic peptides and proteins in diabetic retinopathy.
abstract: OBJECTIVE
  To evaluate the degree of phosphorylation of vitreous proteins in patients with type 2 diabetes mellitus and diabetic retinopathy compared with a group of control subjects without diabetes and of similar age and sex.
  
  
  METHODS
  In samples obtained after vitrectomy for diabetic retinopathy in patients and for macular hole in control subjects, immunoblot techniques were applied to a mini-array system for quantification of a wide range of chemokines and vasoactive peptides and proteins. Antiphosphotyrosine antibody was used for tyrosine phosphorylation evaluation and results were expressed as the percentage of variation compared with that in control subjects.
  
  
  RESULTS
  Samples from eight patients with type 2 diabetes and from eight control subjects were analyzed. The total quantity of proteins analyzed was similar in both patients and control subjects. Tyrosine phosphorylation was very significantly decreased (<20%, P < 0.05) in diabetic patients with respect to the control group in growth-related oncogene, human cytokine I-309, interleukin-13, monocyte colony-stimulating factor, macrophage-derived chemokine, stem cell factor, transforming growth factor-beta1, angiogenin, and oncostatin M. A significant decrease in phosphorylation (between 20% and 40%, P < 0.05) was observed in epithelial neutrophil-activating peptide 78; granulocyte colony-stimulating factor; granulocyte-monocyte-stimulating colony factor; IL-5, -6, -7, -8, -10, and -12p40p70; monokine induced by interferon-gamma; macrophage inflammatory protein 1-gamma; and normal T expressed and secreted cytokine (RANTES) in comparison with that in the control subjects. The greatest decrease in phosphorylation status was found in IL-1-alpha and -1beta.
  
  
  CONCLUSIONS
  Diabetic retinopathy is associated with a decrease in tyrosine phosphorylation of many vitreous proteins which may indicate an alteration in protein functionality or action even before significant quantitative variations.
authors.affiliation: Endocrinology and Nutrition Department, Germans Trias i Pujol University Hospital, Universitat Autònoma de Barcelona, Badalona, Spain.
authors.forename: Jordi L
authors.initials: JL
authors.lastname: Reverter
authors.forename: Jeroni
authors.initials: J
authors.lastname: Nadal
authors.forename: Josep María
authors.initials: JM
authors.lastname: Fernández-Novell
authors.forename: Joan
authors.initials: J
authors.lastname: Ballester
authors.forename: Laura
authors.initials: L
authors.lastname: Ramió-Lluch
authors.forename: María Montserrat
authors.initials: MM
authors.lastname: Rivera
authors.forename: Javier
authors.initials: J
authors.lastname: Elizalde
authors.forename: Santiago
authors.initials: S
authors.lastname: Abengoechea
authors.forename: Joan J
authors.initials: JJ
authors.lastname: Guinovart
authors.forename: Joan Enric
authors.initials: JE
authors.lastname: Rodríguez-Gil
mesh_terms: D043925:Angiogenesis Inducing Agents / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000378:metabolism*; D005136:Eye Proteins / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D018836:Inflammation Mediators / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000378:metabolism; D010766:Phosphorylation; D040081:Protein Array Analysis; D014443:Tyrosine / Q000378:metabolism*; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D043925:Angiogenesis Inducing Agents; D016207:Cytokines; D005136:Eye Proteins; D018836:Inflammation Mediators; D010455:Peptides; D014443:Tyrosine