title: Aqueous Humor Biomarkers of Müller Cell Activation in Diabetic Eyes.
abstract: OBJECTIVE
  To identify early biomarkers of retinal Müller cell activation in diabetic eyes with or without clinically detectable signs of diabetic retinopathy (DR).
  
  
  METHODS
  This study was a cross-sectional comparative case series. The aqueous humor (AH) of 34 eyes was collected in 12 healthy controls, 11 diabetic patients without DR, and 11 diabetic patients with nonproliferative DR. Full ophthalmic examination and spectral-domain optical coherence tomography were performed in all eyes. Glial fibrillary acidic protein (GFAP), aquaporin 1 (AQP1), and aquaporin 4 (AQP4) were quantified in AH samples as biomarkers of Müller cell activity by ELISA. Statistical analysis was performed with ANOVA followed by Tukey-Kramer post hoc test.
  
  
  RESULTS
  There was no significant difference in the age among the three groups. Mean concentration of GFAP, AQP1, and AQP4 significantly increased in diabetic eyes versus controls (P < 0.05, for each comparison). Glial fibrillary acidic protein and AQP1 showed an approximate 2-fold increase, whereas AQP4 showed an approximate 25-fold increase in diabetics with DR versus controls. In diabetics without DR, AQP4 showed an approximate 6-fold increase versus controls.
  
  
  CONCLUSIONS
  Glial fibrillary acidic protein, AQP1, and AQP4-biomarkers of Müller cell activity-are significantly increased in human eyes with diabetes, confirming that Müller cells are precociously affected by diabetes mellitus.
authors.affiliation: Department of Ophthalmology University of Padova, Padova, Italy.
authors.forename: Stela
authors.initials: S
authors.lastname: Vujosevic
authors.affiliation: Fondazione G. B. Bietti, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Micera
authors.affiliation: Department of Ophthalmology University of Padova, Padova, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Bini
authors.affiliation: Department of Ophthalmology University of Padova, Padova, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Berton
authors.affiliation: Fondazione G. B. Bietti, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy.
authors.forename: Graziana
authors.initials: G
authors.lastname: Esposito
authors.affiliation: Department of Ophthalmology University of Padova, Padova, Italy 2Fondazione G. B. Bietti, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Midena
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D051398:Aquaporin 1 / Q000378:metabolism*; D051401:Aquaporin 4 / Q000378:metabolism*; D001082:Aqueous Humor / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000378:metabolism*; D063928:Ependymoglial Cells / Q000378:metabolism*; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000378:metabolism; D041623:Tomography, Optical Coherence
chemical_list: D051401:Aquaporin 4; D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein; D051398:Aquaporin 1