Activation of microglia in haemorrhage microzones in human embryonic cortex. An ultrastructural description.
We have noted the presence within parietal cortex of microzones of haemorrhage in two 14 week gestation fetuses. These were obtained from mothers with no clinical history indicative of infection or other pathological developmental data. The microzones of haemorrhage were complicated by degenerative changes in adjacent neurones and activation of putative microglial cells while other surrounding regions of developing cortex showed no signs of destructive alterations. This indicates that these zones are not simply the result of the termination procedure. Microglia associated with these haemorrhagic microzones showed increased vacuolization, phagocytic activity and abundant phagosomes. Although the cause of the microzones of haemorrhage is unknown, these observations are of interest since they are the first demonstration of possible activation of microglia in such an early stage of human development. This finding suggests that the presence of microhaemorrhage and associated neuronal death may provide an inducible stimulus of microglial cells during early brain development, even before programmed neuronal death occurs.
Bobryshev
Y V
YV
Institute of the Human Brain, St. Petersburg, Russia.
Ashwell
K W
KW
D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000196:embryology / Q000473:pathology* / Q000648:ultrastructure*; D002543:Cerebral Hemorrhage / Q000196:embryology* / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008833:Microcirculation / Q000473:pathology / Q000648:ultrastructure; D017628:Microglia / Q000473:pathology* / Q000648:ultrastructure*; D009410:Nerve Degeneration; D010587:Phagocytosis