1699 A TRANSMISSION ELECTRON MICROSCOPY STUDY OF HUMAN CEREBRAL CORTICAL AND GERMINAL MATRIX (GM) BLOOD VESSELS IN PREMATURE NEONATES

Abstract

Intracranial hemorrhage in premature human neonates is a major cause of mortality and morbidity. The hemorrhage usually originates in the GM over the caudate nucleus. Although structural susceptibility of the GM blood vessels to neonatal stress has been suggested as a cause for hemorrhage, histological confirmation is lacking. Because cortical hemorrhage in prematures is less frequent, we compared the ultrastructural morphology of blood vessels in the GM with those of the cerebral cortex. We studied prematures of 22-27 weeks gestation with and without GM and intraventricular hemorrhage. Autopsy materials were obtained less than 2 hours postmortem, fixed in glutaraldehyde and examined by transmission electron microscopy.

Our observations are that the cortical blood vessels uniformly have mature characteristics: continuous basal lamina, tight junctions, absence of fenestrations and complete pericytic encirclement. In the GM, however, there were 2 types of blood vessels. One type resembled the cortical vessels with all the characteristics of maturity. The second type had all the characteristics of immature blood vessels: presence of fenestrations and absence of a continuous basal lamina, tight junctions, and full encirclement by pericytes.

We postulate that the presence of structurally immature blood vessels in the GM makes this area more susceptible to hemorrhage.

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