title: Differential expression levels of collagen 1A2, tissue inhibitor of metalloproteinase 4, and cathepsin B in intracranial aneurysms.
abstract: OBJECTIVE
  Intracranial aneurysms (IAs) express a variety of differentially expressed genes when compared to the normal artery. The aim of this study was to evaluate the expression level of a few genes in the aneurysm wall and to correlate them with various clinicoradiological factors.
  
  
  METHODS
  The mRNA level of collagen 1A2 (COL1A2), tissue inhibitor of metalloproteinase 4 (TIMP4), and cathepsin B (CTSB) genes were studied in 23 aneurysmal walls and 19 superficial temporal arteries harvested from 23 patients undergoing clipping of IAs, by real-time polymerase chain reaction method.
  
  
  RESULTS
  The mean fold change of COL1A2 gene between the aneurysm sample and the superficial temporal artery (STA) sample was 2.46 ± 0.12, that of TIMP4 gene was 0.31 ± 0, and that of CTSB gene was 31.47 ± 39.01. There was a positive correlation of TIMP4 expression level with maximum diameter of aneurysm (P = 0.008) and fundus of aneurysm (P = 0.012). The mean fold change of CTSB of patients who had preoperative hydrocephalus in the computed tomogram (CT) scan of the head at admission was 56.16 and that of the patients who did not have hydrocephalus was 13.51 (P = 0.008). The mean fold change of CTSB of patients who developed fresh postoperative deficits or worsening of the preexisting deficits was 23.64 and that of the patients who did not develop was 42.22 (P = 0.039).
  
  
  CONCLUSIONS
  COL1A2 gene and CTSB genes were overexpressed, and TIMP4 gene was underexpressed in the aneurysmal sac compared to STA and their expression levels were associated with a few clinicoradiological factors.
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: R Arun
authors.initials: RA
authors.lastname: Babu
authors.affiliation: Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Pradip
authors.initials: P
authors.lastname: Paul
authors.affiliation: Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Meera
authors.initials: M
authors.lastname: Purushottam
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Dwarakanath
authors.initials: D
authors.lastname: Srinivas
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Sampath
authors.initials: S
authors.lastname: Somanna
authors.affiliation: Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Jain
mesh_terms: D002401:Cathepsin B / Q000235:genetics / Q000378:metabolism*; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D002532:Intracranial Aneurysm / Q000235:genetics / Q000378:metabolism*; D013699:Temporal Arteries / Q000378:metabolism; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics / Q000378:metabolism*; D000097792:Tissue Inhibitor of Metalloproteinase-4
chemical_list: D002401:Cathepsin B; D024042:Collagen Type I; D019714:Tissue Inhibitor of Metalloproteinases; D000097792:Tissue Inhibitor of Metalloproteinase-4; C000601279:COL1A2 protein, human; C533912:CTSB protein, human