Alkaline phosphatase histochemical staining in the study of germinal matrix hemorrhage and brain vascular morphology in a very-low-birth-weight neonate.

We evaluated the utility of alkaline phosphatase (AP) histochemical staining for studying intraparenchymal vascular morphology in the brain of a 31-wk-gestation (1480 g) neonate who died of respiratory insufficiency after 23 h. In this baby, afferent cerebral vessels (arteries, arterioles, and capillaries) stained with AP, whereas efferent vessels (venules, veins) did not. The large periventricular channels in the germinal matrix were determined to be veins, according to AP staining criteria. Arterioles connected with these large periventricular veins after passing through 4- to 6-microns capillaries. Branchings and connections of the cerebral circulation were conventional; i.e. no arterial rete or arteriovenous shunts were found. With this method of differential vascular staining, bleeding in the germinal matrix was found to be perivenous only. No dilated capillaries or arterioles were seen. Smooth muscle was identified in extrastriatal medullary arteries. This preliminary investigation suggests that AP histochemical staining is an excellent method for studying brain vascular morphology and pathology of the very-low-birthweight neonate.