The blood brain barrier in human leukodystrophies and allied diseases. Ultrastructural and morphometric studies on the capillaries in brain biopsies.

Capillaries in brain biopsies obtained from patients with globoid cell leukodystrophy (GLD), adreno-leukodystrophy (ALD), Canavan's disease (spongy degeneration) and Alexander's disease were examined ultrastructurally and morphometrically. The numbers of pinocytotic vesicles were significantly increased in capillaries in the white matter of all these patients except for a patient with GLD, in comparison with those in the gray matter of each patient. Enlargement of the perivascular space (PVS) was also observed in the white matter more frequently, together with collagen fibers and cytoplasm of infiltrating cells in the patients with ALD, Canavan's disease and Alexander's disease. In a case of GLD, the enlargement of PVS was less although demyelination was as advanced as in a case of ALD. These pathological findings were correlated with the positive contrast enhancement of computerized tomography (CT) images which have been reported in these white matter disorders. It is postulated that the increase of pinocytotic vesicles and the enlargement of PVS are closely related with the disruption of blood-brain barrier BBB) in these conditions.