title: Analysis of the blood-retinal barrier: its relation to clinical and metabolic factors and progression to retinopathy in juvenile diabetics. A 4-year follow-up study.
abstract: BACKGROUND
  The study was carried out to evaluate the correlation between blood-retinal barrier (BRB) permeability and the development of diabetic retinopathy (DR) and to assess the metabolic and clinical factors related to DR over a 4-year period by means of vitreous fluorophotometry (VF).
  
  
  METHODS
  Thirty-five type I diabetics with no retinopathy, age 7-21 years (mean 14.32 +/- 2.1 years) were enrolled in this longitudinal study. Two visits included standard ophthalmological examination, fluorescein angiography and VF were performed, on entry into the study and 4 years later. The following risk factors in DR were analyzed: age, duration of diabetes, blood pressure, cholesterol, triglycerides, fasting blood glucose levels, glycosylated hemoglobin (HbA1c), insulin dose/kg body weight (IDBW), fructosamine and albuminuria. To estimate the BRB permeability we adopted the vitreous penetration ratio transmittance (VPRt) value.
  
  
  RESULTS
  At 4-year follow-up the mean VPRt had significantly increased. During that time 13 patients developed DR and their final mean VPRt was significantly higher than that in non-DR patients. Additionally, the initial mean VPRt was higher but not significantly so, in patients that later developed DR than in non-DR subjects. A constant linear correlation was found between VPRt and duration of diabetes, HbA1c and microalbuminuria.
  
  
  CONCLUSIONS
  VF is a quantitative method that could measure and predict the breakdown of the BRB before angiographic retinopathy in type I diabetics. The major clinical and metabolic factors related to alterations in the BRB are duration of diabetes, HbA1c and microalbuminuria.
authors.affiliation: Department of Ophthalmology, Hospital de Móstoles, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Castillo
authors.forename: J M
authors.initials: JM
authors.lastname: Benitez del Castillo
authors.forename: D
authors.initials: D
authors.lastname: Diaz
authors.forename: O
authors.initials: O
authors.lastname: Sayagues
authors.forename: J L
authors.initials: JL
authors.lastname: Ruibal
authors.forename: J
authors.initials: J
authors.lastname: Garcia-Sanchez
mesh_terms: D000293:Adolescent; D000328:Adult; D001813:Blood-Retinal Barrier; D002199:Capillary Permeability; D002648:Child; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D015590:Fluorophotometry; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D014822:Vitreous Body / Q000473:pathology