title: Elevated plasma CD105 and vitreous VEGF levels in diabetic retinopathy.
abstract: Diabetic retinopathy is the leading cause of blindness in the industrialized world. Hyperglycaemia induces retinal hypoxia that upregulates a range of vasoactive factors which may lead to macular oedema and/or angiogenesis and hence potentially sight threatening retinopathy. In this study, we have focused on the association of CD105 and vascular endothelial growth factor (VEGF) with the development and progression of diabetic retinopathy by means of quantifying their expression in the plasma and vitreous of diabetic patients. CD105 levels were quantified in the plasma of 38 type I diabetic patients at various stages of retinopathy and 15 non-diabetic controls. In an additional cohort of 11 patients with advanced proliferative retinopathy and 23 control subjects, CD105 and VEGF were measured in the vitreous. The values were expressed as median (range) and statistical analysis was carried out using the non-parametric Mann-Whitney U test. Plasma CD105 levels were significantly increased in diabetic patients [1.8 (1.1-2.4) ng/ml] compared with non-diabetic controls [0.7 (0.3-1.8) ng/ml] (p<0.01). Plasma CD105 levels were elevated in diabetic patients with all stages of retinopathy, the highest level was observed in background retinopathy [2.3 (2.1-2.5) ng/ml] followed by proliferative retinopathy [2.1 (0.9-2.8) ng/ml] and advanced proliferative retinopathy [1.4 (0.6-1.8) ng/ml]. Vitreous contents of CD105 did not differ between controls and patients with advanced proliferative retinopathy, but vitreous levels of VEGF were elevated by approximately 3-fold in patients with advanced proliferative retinopathy [7.2 (1.90-15.60) ng/ml] compared with the control subjects [1.80 (1.10-2.210)] (p<0.01). These observations indicate that plasma levels of CD105 and vitreous levels of VEGF are associated with diabetic retinopathy, suggesting that CD105 and the angiogenic factor VEGF may play a critical role in the development and progression of diabetic retinopathy. Further studies are required to determine whether circulating CD105 levels could serve as a surrogate marker for early stage retinopathy and for monitoring disease progression.
authors.affiliation: Department of Medicine, Manchester Royal Infirmary, Manchester, M13 9PT, UK. Rayaz.a.malik@manchester.ac.uk
authors.forename: R A
authors.initials: RA
authors.lastname: Malik
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: W
authors.initials: W
authors.lastname: Aziz
authors.forename: J A
authors.initials: JA
authors.lastname: Olson
authors.forename: A
authors.initials: A
authors.lastname: Vohra
authors.forename: K C
authors.initials: KC
authors.lastname: McHardy
authors.forename: J V
authors.initials: JV
authors.lastname: Forrester
authors.forename: A J M
authors.initials: AJ
authors.lastname: Boulton
authors.forename: P B
authors.initials: PB
authors.lastname: Wilson
authors.forename: D
authors.initials: D
authors.lastname: Liu
authors.forename: D
authors.initials: D
authors.lastname: McLeod
authors.forename: S
authors.initials: S
authors.lastname: Kumar
mesh_terms: D015703:Antigens, CD / Q000032:analysis / Q000097:blood; D015415:Biomarkers / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood; D003930:Diabetic Retinopathy / Q000097:blood* / Q000276:immunology; D000071063:Endoglin; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D011956:Receptors, Cell Surface; D012016:Reference Values; D019010:Vascular Cell Adhesion Molecule-1 / Q000032:analysis / Q000097:blood*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis / Q000097:blood*; D014822:Vitreous Body / Q000737:chemistry
chemical_list: D015703:Antigens, CD; D015415:Biomarkers; C064206:ENG protein, human; D000071063:Endoglin; D011956:Receptors, Cell Surface; D019010:Vascular Cell Adhesion Molecule-1; D042461:Vascular Endothelial Growth Factor A