title: In vivo CHI3L1 (YKL-40) expression in astrocytes in acute and chronic neurological diseases.
abstract: BACKGROUND
  CHI3L1 (YKL-40) is up-regulated in a variety of inflammatory conditions and cancers. We have previously reported elevated CHI3L1 concentration in the cerebrospinal fluid (CSF) of human and non-human primates with lentiviral encephalitis and using immunohistochemistry showed that CHI3L1 was associated with astrocytes.
  
  
  METHODS
  In the current study CHI3L1 transcription and expression were evaluated in a variety of acute and chronic human neurological diseases.
  
  
  RESULTS
  ELISA revealed significant elevation of CHI3L1 in the CSF of multiple sclerosis (MS) patients as well as mild elevation with aging. In situ hybridization (ISH) showed CHI3L1 transcription mostly associated with reactive astrocytes, that was more pronounced in inflammatory conditions like lentiviral encephalitis and MS. Comparison of CHI3L1 expression in different stages of brain infarction showed that YKL40 was abundantly expressed in astrocytes during acute phases and diminished to low levels in chronic infarcts.
  
  
  CONCLUSIONS
  Taken together, these findings demonstrate that CHI3L1 is induced in astrocytes in a variety of neurological diseases but that it is most abundantly associated with astrocytes in regions of inflammatory cells.
authors.affiliation: Department of Pathology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA 15213, USA. bonnehbarkayd@upmc.edu
authors.forename: Dafna
authors.initials: D
authors.lastname: Bonneh-Barkay
authors.forename: Guoji
authors.initials: G
authors.lastname: Wang
authors.forename: Adam
authors.initials: A
authors.lastname: Starkey
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Hamilton
authors.forename: Clayton A
authors.initials: CA
authors.lastname: Wiley
mesh_terms: D054392:Adipokines; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D000071451:Chitinase-3-Like Protein 1; D002908:Chronic Disease; D005260:Female; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D037102:Lectins / Q000235:genetics / Q000378:metabolism*; D008254:Macaca nemestrina; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D009422:Nervous System Diseases / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D020521:Stroke / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology
chemical_list: D054392:Adipokines; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D037102:Lectins