title: Elevated LRP6 levels correlate with vascular endothelial growth factor in the vitreous of proliferative diabetic retinopathy.
abstract: OBJECTIVE
  To measure intravitreal low-density lipoprotein receptor-related protein 6 (LRP6) and vascular endothelial growth factor (VEGF) levels in the eyes of patients with proliferative diabetic retinopathy (PDR) and to observe their correlation with PDR activity.
  
  
  METHODS
  Fifty-five eyes of 55 patients were enrolled consecutively. Vitreous samples from 30 eyes with PDR and 25 eyes with nondiabetic macular disease were collected. Active PDR was present in 16 patients and quiescent PDR in 14 patients according to retinal neovascularization. LRP6 and VEGF concentrations in samples were determined using enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  ELISA revealed significant increases in the vitreous levels of VEGF in eyes affected with PDR compared to the controls (p<0.001). The mean concentrations of LRP6 were also higher in the vitreous samples from patients with PDR compared to the nondiabetic controls: 39.85 ng/ml and 15.48 ng/ml, respectively (p=0.002). In addition, the vitreous levels of LRP6 and VEGF were significantly higher in active PDR than in quiescent PDR (p=0.022 and p=0.015, respectively). Furthermore, a significant positive correlation was found between intravitreal levels of LRP6 and VEGF in patients with PDR (r=0.567, p=0.001). However, comparison of patients with PDR with controls revealed that the plasma levels of LRP6 were not significantly different between the two groups (p=0.636).
  
  
  CONCLUSIONS
  LRP6 and VEGF levels in the vitreous body from patients with PDR were increased and correlated mutually. LRP6 may be a good diagnostic biomarker and a new therapeutic target for PDR.
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China ; Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
authors.forename: Xinxiao
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Ma
authors.affiliation: Department of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Lu
authors.affiliation: Clinical Lab of Tissue&Cell Research Center, Department of Biotech Treatment, Logistics College of Chinese People's Armed Police Force, Tianjin, China.
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Hong
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Ophthalmology and Visual Science Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Peng
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D016022:Case-Control Studies; D003930:Diabetic Retinopathy / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D060488:Low Density Lipoprotein Receptor-Related Protein-6 / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015861:Retinal Neovascularization / Q000097:blood / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D014822:Vitreous Body / Q000378:metabolism*; D060449:Wnt Signaling Pathway
chemical_list: D015415:Biomarkers; C555475:LRP6 protein, human; D060488:Low Density Lipoprotein Receptor-Related Protein-6; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A