Hippocampal neuronal atrophy and cognitive function in delayed poststroke and aging-related dementias.
OBJECTIVE
We have previously shown delayed poststroke dementia in elderly (≥75 years old) stroke survivors is associated with medial temporal lobe atrophy; however, the basis of the structural and functional changes is unknown.


METHODS
Using 3-dimensional stereological methods, we quantified hippocampal pyramidal neuronal volumes and densities in a total of 95 postmortem samples from demented and nondemented poststroke survivors within our prospective Cognitive Function after Stroke study and subjects pathologically diagnosed with vascular dementia, Alzheimer disease, and mixed Alzheimer disease and vascular dementia syndrome.


RESULTS
Hippocampal CA1 but not CA2 subfield neuron density was affected in poststroke, Alzheimer disease, vascular dementia, and mixed dementia groups relative to control subjects (P<0.05). Neuronal volume was reduced in the poststroke dementia relative to poststroke nondemented group in both CA1 and CA2, although there were no apparent differences in neuronal density. Poststroke nondemented neuronal volumes were similar to control subjects but greater than in all dementias (P<0.05). Neuronal volumes positively correlated with global cognitive function and memory function in both CA1 and CA2 in poststroke subjects (P<0.01). Degrees of neuronal atrophy and loss were similar in the poststroke dementia and vascular dementia groups. However, in the entorhinal cortex layer V, neuronal volumes were only impaired in the mixed and Alzheimer disease groups (P<0.05).


CONCLUSIONS
Our results suggest hippocampal neuronal atrophy is an important substrate for dementia in both cerebrovascular and neurodegenerative disease.
Centre for Brain Ageing and Vitality, Institute for Ageing and Health, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne, UK.
Elizabeth
E
Gemmell
Helen
H
Bosomworth
Louise
L
Allan
Roslyn
R
Hall
Ahmad
A
Khundakar
Arthur E
AE
Oakley
Vincent
V
Deramecourt
Tuomo M
TM
Polvikoski
John T
JT
O'Brien
Raj N
RN
Kalaria
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology* / Q000523:psychology*; D000544:Alzheimer Disease / Q000473:pathology; D001284:Atrophy; D056547:CA1 Region, Hippocampal / Q000473:pathology; D056651:CA2 Region, Hippocampal / Q000473:pathology; D002452:Cell Count; D003071:Cognition / Q000502:physiology*; D003704:Dementia / Q000473:pathology* / Q000523:psychology*; D018728:Entorhinal Cortex / Q000473:pathology; D056344:Executive Function; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology; D019636:Neurodegenerative Diseases / Q000473:pathology; D009474:Neurons / Q000473:pathology*; D011446:Prospective Studies; D017966:Pyramidal Cells / Q000473:pathology; D020521:Stroke / Q000150:complications*; D017741:Survivors; D014015:Tissue Banks