title: The brain-derived neurotrophic factor Val66Met polymorphism and degeneration of the corticospinal tract after stroke: a diffusion tensor imaging study.
abstract: OBJECTIVE
  A common single nucleotide polymorphism, Val66Met, in the human brain-derived neurotrophic factor (BDNF) gene has a potential role in the pathogenesis and treatment of stroke. The relevance of the BDNF Val66Met polymorphism to long-term stroke outcomes was examined, specifically with respect to changes in corticospinal integrity.
  
  
  METHODS
  Thirty-five stroke patients with unilateral motor weakness were genotyped within 2 weeks after onset (T1), and changes in the integrity of the ipsilesional corticospinal tract (CST) as well as alterations in motor function at 1 month (T2) and 3 months after onset (T3) were tracked.
  
  
  RESULTS
  On the basis of the Fugl-Meyer assessment upper extremity score, carriers of the Met allele (Val/Met and Met/Met) showed poorer motor outcomes at T2 and T3 compared to carriers of only the Val allele (Val/Val). For both BDNF allele types, patients exhibited characteristic degeneration of the CST compared to healthy controls. There were no differences between the two genotypes with respect to time-dependent changes in diffusion-tensor-imaging-derived parameters of the CST. However, the two groups showed different relationships between motor outcomes and directional diffusivities according to the elapsed time after onset. Poorer motor function was associated with lower axial diffusivity values for the Val/Val genotype group in the sub-acute phase (T1 and T2) but with higher radial diffusivity values for the Val/Met and Met/Met genotype group in the early chronic phase (T3).
  
  
  CONCLUSIONS
  Motor recovery in stroke patients may be affected by the BDNF Val66Met polymorphism, possibly through its effects on distinct pathological processes underlying corticospinal degeneration.
authors.affiliation: Department of Rehabilitation Medicine, Armed Forces Capital Hospital, Bundang-gu, Seongnam, Korea.
authors.forename: E-J
authors.initials: EJ
authors.lastname: Kim
authors.affiliation: Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: C-H
authors.initials: CH
authors.lastname: Park
authors.affiliation: Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: W H
authors.initials: WH
authors.lastname: Chang
authors.affiliation: Department of Health Science and Technology, Department of Medical Device Management & Research, SAIHST, Sungkyunkwan University, Seoul, Korea.
authors.forename: A
authors.initials: A
authors.lastname: Lee
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: S T
authors.initials: ST
authors.lastname: Kim
authors.affiliation: Department of Rehabilitation Medicine, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea.
authors.forename: Y-I
authors.initials: YI
authors.lastname: Shin
authors.affiliation: Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.|Department of Health Science and Technology, Department of Medical Device Management & Research, SAIHST, Sungkyunkwan University, Seoul, Korea.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011712:Pyramidal Tracts / Q000473:pathology*; D020127:Recovery of Function / Q000235:genetics*; D020521:Stroke / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C579455:BDNF protein, human
keywords: brain-derived neurotrophic factor; diffusion tensor imaging; motor skills; pyramidal tracts; recovery of function; stroke