title: Association of monocyte chemoattractant protein-1 (MCP-1)2518A/G polymorphism with proliferative diabetic retinopathy in northern Chinese type 2 diabetes.
abstract: BACKGROUND
  The pathogenesis of proliferative diabetic retinopathy (PDR) remains poorly understood. Recent studies have implicated that monocyte chemoattractant protein-1 (MCP-1) is associated with diabetic microvascular or macrovascular complications. However, the relationship between single nucleotide polymorphism(SNP)c.2518A/G -rs1024611 in the MCP-1 gene with diabetic retinopathy remains controversial. In the present study, we evaluated the association of SNP in the MCP-1 gene with diabetic retinopathy (DR) and diabetic macular edema (DME) in a Chinese population from Northern China with type 2 diabetes.
  
  
  METHODS
  We conducted a case-control study, which enrolled 1,043 subjects with type 2 diabetes (528 with DR, including 277PDR; 515 without DR), and SNP genotyping of c.2518A/G in the MCP-1 gene was performed using the polymerase chain reaction. Genomic DNA was isolated from 3 ml samples of whole blood using a modified conventional DNA extraction method. The genotype and allele frequencies of 2518A/G were studied by using an automated DNA sequencer (ABI PRISM 3730 DNA Sequencer).
  
  
  RESULTS
  The demographic and clinical characteristics did not differ among genotype subgroups. The MCP-1(-2518) GG genotype was significantly associated with DR susceptibility with OR of 1.481 (95 % CI, 1.019-2.153) (P = 0.046). There were no significant differences in the MCP-1(-2518) G allele frequencies in DR compared to non-diabetic retinopathy (DNR) (P > 0.05, OR = 0.841, 95 % CI, 0.705-1.002). The MCP-1(-2518) GG genotype was significantly associated with high-risk PDR susceptibility with OR of 2.656 (95 % CI, 1.222-5.775) (P = 0.014). The MCP-1(-2518) G allele was significantly increased in high-risk PDR patients (P = 0.020, OR = 1.481, 95 % CI, 1.070-2.051) compared with A allele. Genotype and allele frequencies of various DME of the DR patients were compared, but there were no significant associations established (P > 0.05).
  
  
  CONCLUSIONS
  It is likely that the MCP-1 c.2518G/G genotype is a susceptibility gene for DR in Chinese type 2 diabetic patients, especially the high-risk PDR. There is no association with DME and c.2518G/G.
authors.affiliation: Key Laboratory of Harbin Medical University Eye Center, Eye Hospital, First Affiliated Hospital of Harbin Medical University, 23 Youzheng Street, Nangang District, Harbin, 150001, Heilongjiang Province, People's Republic of China.
authors.forename: Li
authors.initials: L
authors.lastname: Dong
authors.forename: Xiao Ying
authors.initials: XY
authors.lastname: Lv
authors.forename: Bin Jie
authors.initials: BJ
authors.lastname: Wang
authors.forename: Ye Qing
authors.initials: YQ
authors.lastname: Wang
authors.forename: Hua
authors.initials: H
authors.lastname: Mu
authors.forename: Zhuo Lei
authors.initials: ZL
authors.lastname: Feng
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People / Q000235:genetics*; D016022:Case-Control Studies; D018932:Chemokine CCL2 / Q000235:genetics*; D002681:China / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D060005:Genotyping Techniques; D006801:Humans; D008269:Macular Edema / Q000175:diagnosis / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide
chemical_list: C111835:CCL2 protein, human; D018932:Chemokine CCL2