Parvalbumin-, calbindin-, and calretinin-immunoreactive hippocampal interneuron density in autism.
BACKGROUND
There has been a long-standing interest in the possible role of the hippocampus in autism and both postmortem brain and neuroimaging studies have documented varying abnormalities in this limbic system structure.


OBJECTIVE
This study investigates the density of subsets of hippocampal interneurons, immunostained with the calcium binding proteins, calbindin (CB), calretinin (CR) and parvalbumin (PV) to determine whether specific subpopulations of interneurons are impacted in autism.


METHODS
Unbiased stereological techniques were used to quantify the neuronal density of these immunoreactive subpopulations of gamma-aminobutyric acid-ergic (GABAergic) interneurons analyzed in the CA and subicular fields in postmortem brain material obtained from five autistic and five age-, gender- and postmortem interval-matched control cases.


RESULTS
Results indicate a selective increase in the density of CB-immunoreactive interneurons in the dentate gyrus, an increase in CR-immunoreactive interneurons in area CA1, and an increase in PV-immunoreactive interneurons in areas CA1 and CA3 in the hippocampus of individuals with autism when compared with controls.


CONCLUSIONS
Although our sample size is small, these findings suggest that GABAergic interneurons may represent a vulnerable target in the brains of individuals with autism, potentially impacting upon their key role in learning and information processing. These preliminary findings further suggest the need for future more expanded studies in a larger number of postmortem brain samples from cases of autism and controls.
Lawrence
Y A
YA
Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA. yuri.lawrence@tufts.edu
Kemper
T L
TL
Bauman
M L
ML
Blatt
G J
GJ
D000293:Adolescent; D000328:Adult; D001321:Autistic Disorder / Q000503:physiopathology*; D056547:CA1 Region, Hippocampal / Q000503:physiopathology; D056654:CA3 Region, Hippocampal / Q000503:physiopathology; D064032:Calbindin 2; D064026:Calbindins; D002452:Cell Count; D018891:Dentate Gyrus / Q000503:physiopathology; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D007150:Immunohistochemistry; D007395:Interneurons / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010320:Parvalbumins / Q000378:metabolism*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
C576764:CALB2 protein, human; D064032:Calbindin 2; D064026:Calbindins; D010320:Parvalbumins; D064030:S100 Calcium Binding Protein G; D005680:gamma-Aminobutyric Acid