title: The Relationship between HIF-2α and VEGF with Radiographic Severity in the Primary Osteoarthritic Knee.
abstract: OBJECTIVE
  The aim of this study was to determine the relationship of hypoxia-inducible factor-2 (HIF-2α) and vascular endothelial growth factor (VEGF) with radiographic severity in primary osteoarthritis (OA) of the knee. Expression of these two factors in cartilage samples from OA knee joints was examined at mRNA and protein levels.
  
  
  METHODS
  Knee joints were examined using plain radiographs, and OA severity was assessed using the Kellgren and Lawrence (KL) grading system. Specimens were collected from 29 patients (31 knees) who underwent total knee replacement because of severe medial OA of the knee (KL grades 3 and 4), 16 patients who underwent knee arthroscopy (KL grade 2), and 5 patients with traumatic knees (KL grade 0). HIF-2α and VEGF expression was quantified by real-time polymerase chain reaction and western blotting.
  
  
  RESULTS
  Cartilage degeneration correlated with the radiographic severity grade. OA severity, determined using the Mankin scale, correlated positively with the KL grade (r=0.8790, p<0.01), and HIF-2α and VEGF levels with the radiographic severity of knee OA (r=0.7001, p<0.05; r=0.6647, p<0.05).
  
  
  CONCLUSIONS
  In OA cartilage, HIF-2α and VEGF mRNA and protein levels were significantly and positively correlated. The expression of both factors correlated positively with the KL grade. HIF-2α and VEGF, therefore, may serve as biochemical markers as well as potential therapeutic targets in knee OA.
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China. zhoujianlin2005@sina.com.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Jian-lin
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Hong-song
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Hao
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Deng
authors.initials: D
authors.lastname: Shuang
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Shen
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Li
authors.initials: L
authors.lastname: Jian-ping
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Qiu
authors.initials: Q
authors.lastname: Bo
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Weng
authors.initials: W
authors.lastname: Jin-qing
authors.affiliation: Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Feng
mesh_terms: D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001182:Arthroscopy; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood*; D002356:Cartilage / Q000378:metabolism*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood* / Q000000981:diagnostic imaging / Q000503:physiopathology; D012333:RNA, Messenger; D011859:Radiography; D060888:Real-Time Polymerase Chain Reaction; D012720:Severity of Illness Index; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D000099162:Endothelial PAS Domain-Containing Protein 1
keywords: HIF-2α; KL grade; VEGF; cartilage degeneration