ULTRASTRUCTURAL-STUDY OF BRAIN MICROVESSELS IN PATIENTS WITH TRAUMATIC CEREBRAL CONTUSIONS

Brain tissue from ii patients with traumatic cerebral contusions submi tted to surgery was studied. Control biopsy specimens were obtained fr om 5 patients undergoing ventriculo-peritoneal shunts for ''communicat ing'' hydrocephalus. After collection, the small fragments were fixed by immersion in glutaraldehyde-osmium and embedded in Epon. Semi-thin sections stained with toluidine blue were observed with the light micr oscope. Thin sections stained with lead citrate and uranyl acetate wer e observed using a Jeol electron microscope. In tissues from patients with head trauma a clear space most probably corresponding to fluid ac cumulation was systematically observed around microvessels. Ultrastruc turally endothelial cells from these specimens exhibited signs of mark ed intracellular oedema, tight junctions being intact. Pinocytotic act ivity was increased, mainly at the abluminal surface. Swelling of astr ocytic perivascular processes and the appearance of macrophagic cells with voluminous lysosomes were also observed. The authors conclude tha t the oedema of endothelial cells probably represent a central fact in the pathophysiology of traumatic brain oedema and speculate on the pu tative involvement of stretch-activated receptors in this condition.