Untitled

Abstract

Distribution of glucose transporter (GLUT-1) in brain microvascular endothelia, representing the anatomic site of the blood-brain barrier (BBB), was studied in adult, physiologically aged, senescence-accelerated prone (SAMP8) and in scrapie-infected mice. Sections of tissue samples obtained from four brain regions (cerebral cortex, hippocampus, cerebellum, and olfactory bulb) and embedded in Lowicryl K4M were exposed to anti-GLUT-1 antiserum followed by gold-labeled secondary antibody. Labelling density was recorded over luminal and abluminal plasma membranes of the microvascular endothelial cells. We found that the density of immunosignals for GLUT-1 in the cerebral cortex showed a tendency toward insignificant diminution according to the following gradation-adult > SAMP8 > scrapie > aged mice-whereas in the hippocampus, this gradation was slightly different: adult > aged > scrapie > SAMP8 mice. In the cerebellum, immunolabelling was insignificantly diminished in aged mice, whereas it was significantly decreased in scrapie-infected and SAMP8 mice. The intensity of labelling of the vascular endothelium in the olfactory bulb was significantly lower than that in other brain regions, showing a slight decrease in the following sequence: adult > aged > scrapie > SAMP8 mice. These findings suggest that the process of aging as well as of related neurodegenerative disease affects unequally the distribution of GLUT-1 in the vasculature of different brain regions.

Glucose transporters in brain in health and disease

“…hypothalmus, nopt. nuclei of the optical tract Table 3 Expression of glucose transporters in capillary endothelial cells, choroidal epithelial cells, ependymal cells, and tanycytes [39,40,75,77,102,107,120,131,132,134,155,218,245,247,380,385,426,427] Glut2 + (ro.) + (ro.)…”

“… + (ro.) [ 39 , 40 , 75 , 77 , 102 , 107 , 120 , 131 , 132 , 134 , 155 , 218 , 245 , 247 , 380 , 385 , 426 , 427 ] Glut2 + (ro.) + (ro.)…”

“…In various species, GLUT1/Glut1 is abundantly expressed in endothelial cells of the BBB exhibiting different expression levels in different brain regions (Table 3 ) [ 40 , 77 , 155 , 426 , 427 ]. In brain of humans and primates, capillaries with high and low expression of GLUT1 were distinguished [ 76 – 78 ].…”

Astrocytic response to cerebral ischemia is influenced by sex differences and impaired by aging

“…In humans, normal aging results in increased blood–brain barrier permeability (Farrall and Wardlaw, 2009; Montagne et al, 2015) and decreased microvessel density (Brown and Thore, 2011). Furthermore, studies in a senescence-accelerated mouse model have shown that the passage of cytokines through the blood–brain barrier is altered (Banks et al, 2001; McLay et al, 2000), the expression of the glucose transporter GLUT-1 is reduced (Vorbrodt et al, 1999) and there is increased permeability of the blood–brain barrier (Ueno et al, 1993; Pelegri et al, 2007). This increased permeability in the blood–brain barrier may exacerbate cell loss following ischemia.…”

Bioenergetic Impairment in the Neuro-Glia-Vascular Unit: An Emerging Physiopathology during Aging

“…GLUT1 and GLUT3, two key glucose transporters in the NGVU, are decreased in ECs during aging [ 157 - 159 , 183 ], implicating age-related inefficiency of glucose supply from blood to the NGVU. Apart from the reduced expression of GLUTs, the dysfunction of the GLUT1 transporter transferring glucose from the blood to the brain may partly contribute to this inefficient energy transport in the senescent NGVU [ 184 , 185 ]. In addition to glucose, KBs are believed to be a better source from blood to neurons during ischemia or hypoxia [ 43 ].…”