Article

AIM: To determine specific cell types and pathways involved in calcification of
the developing brain. METHOD:
We examined the detailed histopathology of samples
from 28 autopsied brains aged from 22 weeks' gestation to 14 years.
The samples
were selected because they showed calcification associated with a range of
different diseases. Samples were examined with routine stains as well as stains
to show calcification and specific markers for endothelium and macrophages.
RESULTS: Our observations indicate that calcification develops via two main
pathways: dystrophic and vascular. Dystrophic calcification results from membrane
disruption and uncontrolled calcium entry into necrotic (dead) cells in ischaemia
and infections. Vascular calcification appears to be initiated in protein
globules, sometimes intracellular, but outside the endothelium of small vessels.
One case with mutation of the occludin gene, implicating impaired endothelial
integrity, showed this pattern, but identical vascular calcification was seen in
other conditions, including Sturge-Weber syndrome. Another form of vascular
calcification involved the adventitia of arteries; the endothelium was always
spared. INTERPRETATION: Calcification in the developing brain that is not
associated with tissue necrosis is initiated in cells associated with blood
vessels. Calcium incrustation of blood vessels imposes rigidity, reduced vascular
compliance, and altered permeability. This would explain associated atrophy,
gliosis, and (in the developing brain) malformations of the cortex. Our findings
suggest that pericytes initiate non-dystrophic brain calcification, but further
studies are needed to explore this possibility.
CI - (c) 2014 Mac Keith Press.

Langue : ANGLAIS