title: Comparison of aqueous humor cytokine and chemokine levels in diabetic patients with and without retinopathy.
abstract: OBJECTIVE
  To compare the aqueous humor levels of proinflammatory and angiogenic factors of diabetic patients with and without retinopathy.
  
  
  METHODS
  Aqueous humor was collected at the start of cataract surgery from diabetic subjects and non-diabetic controls. The presence and severity of diabetic retinopathy were graded with fundus examination. Levels of 22 different inflammatory and angiogenic cytokines and chemokines were compared.
  
  
  RESULTS
  Aqueous humor samples from 47 diabetic patients (20 without retinopathy, 27 with retinopathy) and 24 non-diabetic controls were included. Interleukin (IL)-2, IL-10, IL-12, interferon-alpha (IFN-α), and tumor necrosis factor (TNF)-α were measurable in significantly fewer diabetic samples, and where measurable, were at lower levels than in non-diabetic controls. IL-6 was measurable in significantly more diabetic samples, and the median levels were significantly higher in the eyes with retinopathy than the eyes without retinopathy and the non-diabetic eyes. The vascular endothelial growth factor (VEGF) level was significantly higher in the diabetic eyes with and without retinopathy compared to the non-diabetic controls. The IL-6 level positively correlated with the monocyte chemotactic protein-1 (CCL2) and interleukin-8 (CXCL8) levels and negatively with the TNF-α level. The VEGF level negatively correlated with the IL-12 and TNF-α levels.
  
  
  CONCLUSIONS
  The aqueous humor cytokine profile of diabetic patients without retinopathy was similar to that of patients with diabetic retinopathy. These cytokines may be useful biomarkers for early detection and prognosis of diabetic retinopathy. Compared to diabetic patients without retinopathy, only the IL-6 and VEGF levels were significantly higher in diabetic patients with retinopathy.
authors.affiliation: Ocular Inflammation and Immunology Services, Singapore National Eye Centre, Singapore.
authors.forename: Chui Ming Gemmy
authors.initials: CM
authors.lastname: Cheung
authors.forename: Maya
authors.initials: M
authors.lastname: Vania
authors.forename: Marcus
authors.initials: M
authors.lastname: Ang
authors.forename: Soon Phaik
authors.initials: SP
authors.lastname: Chee
authors.forename: Jing
authors.initials: J
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001082:Aqueous Humor / Q000737:chemistry*; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D016207:Cytokines / Q000378:metabolism*; D048909:Diabetes Complications; D003920:Diabetes Mellitus / Q000378:metabolism* / Q000473:pathology; D003930:Diabetic Retinopathy / Q000150:complications / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000378:metabolism* / Q000473:pathology; D012720:Severity of Illness Index; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D015415:Biomarkers; D016207:Cytokines; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A