The structure of the perivascular compartment in the old canine brain: a case study

Dilatation of periarteriolar spaces in MRI of the ageing human brains occurs in white matter, basal ganglia and midbrain but not in cerebral cortex. Perivenous collagenous occurs in periventricular but not in subcortical white matter. Here we test the hypotheses that (a) the capacity for dilatation of periarteriolar spaces correlates with the anatomical distribution of leptomeningeal cells coating intracerebral arteries; (b) the regional development of perivenous collagenous in the white matter correlates with the population of intramural cells in the walls of veins. The anatomical distribution of leptomeningeal and intramural cells related to cerebral blood vessels is best documented by electron microscopy, requiring perfusion-fixed tissue not available in human material. We therefore analysed perfusion-fixed brain from a 12-year-old beagle dog as the canine brain represents the anatomical arrangement in the human brain. Results showed regional variation in the arrangement of leptomeningeal cells around blood vessels. Arterioles are enveloped by one complete layer of leptomeninges often with a second incomplete layer in the white matter. Venules showed incomplete layers of leptomeningeal cells. Intramural cell expression was higher in the postcapillary venules of the subcortical white matter when compared to periventricular white matter, suggesting that periventricular collagenosis around venules may be due to a lower resistance in the venular walls. It appears that the regi...
Source: Clinical Science - Category: Biomedical Science Authors: Tags: PublishAheadOfPrint Source Type: research