Changes in periventricular vasculature of rabbit brain following induction of hydrocephalus and after shunting

Abstract

Hydrocephalus was induced in rabbits by injection of silicone oil into the cisterna magna. At 1 and 8 weeks postinjection the rabbits were either sacrificed or treated by cerebrospinal fluid shunting for 1 week. Blood vessel profiles in the periventricular neuropil were examined by light microscopy. In the caudate nucleus, septal area, and corpus callosum, hydrocephalus caused a reduction in the number of capillaries but no changes were observed in the number of larger blood vessels. Shunting reduced the size of the ventricles to normal and the number of capillaries increased if hydrocephalus was present for 1 week prior to shunting. If hydrocephalus was present for 8 weeks prior to shunting, the number of capillaries did not increase. These observations support the concept that collapse of capillaries may account for the decreased cerebral blood flow that has been measured in hydrocephalic brains.

Noninvasive Detection of Changes in Cerebral Blood Flow by Near-Infrared Spectroscopy in a Piglet Model of Hydrocephalus

“…Abbreviations NIRS, near-infrared spectroscopy HbO 2 , oxygenated Hb Hb, deoxygenated Hb HbD, Hb difference signal HbT, total Hb CytOx, oxidized cytochrome aa 3 ICP, intracranial pressure MAP, mean arterial pressure CPP, cerebral perfusion pressure CBF, cerebral blood flow rCBF, regional cerebral blood flow dpf, differential path-length factor Rational management of infantile hydrocephalus requires information about the disturbances in cerebral perfusion and metabolism that may contribute to the development of brain injury. Substantial evidence indicates that impairments of cerebral perfusion and metabolism play a role in the pathogenesis of brain injury secondary to hydrocephalus (1)(2)(3)(4)(5)(6)(7)(8). However, currently there are major limitations in the ability to define changes in cerebral hemodynamics and metabolism quantitatively, continuously, and noninvasively at the bedside of the human infant.…”

Dissociation between Vascular Endothelial Growth Factor Receptor-2 and Blood Vessel Density in the Caudate Nucleus after Chronic Hydrocephalus

“…We have also shown a sustained increase in BVd in the hippocampus after the induction of CH (Dombrowski et al, 2008). Although most studies have described cerebrovascular compression, a few studies have observed increased vascularity in certain brain regions and at various time points in hydrocephalus (Ransohoff et al, 1975;Del Bigio and Bruni, 1988;Jones et al, 1991). The size and direction of these observed BVd changes could not be explained by a simple spatial compression of an intact vascular tree.…”

“…Although most studies have described cerebrovascular compression in CH (Del Bigio and Bruni, 1988), a few studies have observed increased vascular density in certain brain regions and at various time points in CH (Dombrowski et al, 2008;Luciano et al, 2001;Ransohoff et al, 1975). Previously, we have shown an initial decrease in vascularity followed by a return above baseline in cortical gray and periventricular white matter in CH .…”

“…Chronic hydrocephalus (CH) may be considered a form of cerebral ischemia-hypoxia resulting from impaired cerebral blood flow (CBF) as a result of mechanical compression and brain distortion (Del Bigio and Bruni, 1988;Dombrowski et al, 2006;Edwards et al, 2004;Momjian et al, 2004;Owler et al, 2004). Although most studies have described cerebrovascular compression in CH (Del Bigio and Bruni, 1988), a few studies have observed increased vascular density in certain brain regions and at various time points in CH (Dombrowski et al, 2008;Luciano et al, 2001;Ransohoff et al, 1975).…”

Effects of congenital hydrocephalus on the hypothalamic gonadotrophin-releasing hormone system

“…Severity was classified as mild, moderate, and severe relative to each age group. This method has been used repeatedly in both clinical and experimental studies of hydrocephalus, 12,23 and exact measurements of the temporal changes that occur in HTX rats with progressive ventriculomegaly have been reported 24 and correlated with in vivo magnetic resonance imaging assessments of cortical mantle thickness. 19 …”