title: Identification of new pathogenic candidates for diabetic macular edema using fluorescence-based difference gel electrophoresis analysis.
abstract: BACKGROUND
  Diabetic macular edema is the main cause of visual impairment in diabetic patients. The aim of the present study was to explore the differential proteomic pattern of the vitreous fluid from diabetic macular edema patients by means of fluorescence-based difference gel electrophoresis (DIGE).
  
  
  METHODS
  Samples of vitreous from eight type 2 diabetic patients [four with diabetic macular edema without proliferative diabetic retinopathy and four with proliferative diabetic retinopathy without diabetic macular edema), and eight from non-diabetic subjects with idiopathic macular hole (control group) were selected from our vitreous bank for proteomic analysis. To further confirm the potential candidates identified by DIGE, 18 additional samples (six proliferative diabetic retinopathy, six diabetic macular edema and six macular hole, matched by age) were analysed by enzyme-linked immuno sorbent assay (ELISA).
  
  
  RESULTS
  Selecting an abundance ratio of 1.5-fold, p < 0.05, as the threshold for the study, four proteins were specifically associated with diabetic macular edema. Hemopexin was significantly higher in the vitreous fluid of patients with diabetic macular edema in comparison with both control subjects and proliferative diabetic retinopathy patients. By contrast, clusterin, transthyretin and crystallin S were significantly decreased in the vitreous of patients with diabetic macular edema. The differential production of hemopexin, clusterin and transthyretin was further confirmed by ELISA.
  
  
  CONCLUSIONS
  Proteomic analysis by DIGE was useful in identifying new potential candidates involved in the pathogenesis of diabetic macular edema. These results could open up new strategies in the treatment of diabetic macular edema.
authors.affiliation: CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Barcelona, Spain; Diabetes and Metabolism Research Unit, Vall Hebron Institut de Recerca, Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Hernández
authors.forename: Marta
authors.initials: M
authors.lastname: García-Ramírez
authors.forename: Nuria
authors.initials: N
authors.lastname: Colomé
authors.forename: Lidia
authors.initials: L
authors.lastname: Corraliza
authors.forename: Luis
authors.initials: L
authors.lastname: García-Pascual
authors.forename: Joan
authors.initials: J
authors.lastname: Casado
authors.forename: Francesc
authors.initials: F
authors.lastname: Canals
authors.forename: Rafael
authors.initials: R
authors.lastname: Simó
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003930:Diabetic Retinopathy / Q000378:metabolism*; D005136:Eye Proteins / Q000032:analysis / Q000378:metabolism*; D005260:Female; D005453:Fluorescence; D006801:Humans; D008269:Macular Edema / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D040901:Proteomics / Q000379:methods*; D012307:Risk Factors; D057825:Two-Dimensional Difference Gel Electrophoresis / Q000379:methods*; D014822:Vitreous Body / Q000737:chemistry* / Q000378:metabolism
chemical_list: D005136:Eye Proteins
keywords: diabetic macular edema; proteomic analysis; vitreous fluid