Distribution of ICAM-1 immunoreactivity during aging in the human orbitofrontal cortex.
Neurological and psychiatric alterations during aging are associated with increased cerebrovascular disturbances and inflammatory markers such as Intercellular Adhesion Molecule-1 (ICAM-1). We investigated whether the distribution of ICAM-1 immunoreactivity (ICAM-1-I) in histological sections from the left orbitofrontal cortex (ORB) was altered during normal aging. Postmortem tissue from the ORB of nine younger (27-54 years old) and 10 older (60-86) human subjects was collected. Cryostat sections were immunostained only with antibodies to ICAM-1 or together with an antibody to glial fibrillary acidic protein (GFAP). The total area fraction of ICAM-1-I, and the fraction of vascular and extravascular ICAM-1-I were quantified in the gray matter. Furthermore, we examined the association of extravascular ICAM-1-I to GFAP immunoreactive (GFAP-IR) astrocytes. In all subjects, brain blood vessels were similarly ICAM-1 immunoreactive, and in some subjects there was a variable number of extravascular patches of ICAM-1-I. The area fraction of ICAM-1-I was 120% higher (p<.0001) in the old subjects than in the young subjects. This increase localized mostly to the extravascular ICAM-1-I in register with GFAP-IR astrocytes. A much smaller, also age-dependent increase occurred in vascular ICAM-1-I. Our results indicate a dramatic increase in extravascular ICAM-1-I associated to GFAP-IR astrocytes in the ORB in normal aging. This increase may contribute to an enhanced risk for brain inflammatory processes during aging, although a role of extravascular ICAM-1 as a barrier to further inflammation cannot be ruled out.
Miguel-Hidalgo
Jose Javier
JJ
Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216, USA. jmiguel-hidalgo@psychiatry.umsmed.edu
Nithuairisg
Sorcha
S
Stockmeier
Craig
C
Rajkowska
Grazyna
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D005260:Female; D005625:Frontal Lobe / Q000098:blood supply / Q000378:metabolism*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D014018:Tissue Distribution
D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein; D018799:Intercellular Adhesion Molecule-1