Characterisation of glucose transporters in the intact coronary artery endothelium in rats: GLUT-2 upregulated by long-term hyperglycaemia

• Published in: Diabetologia Vol. 47; no. 12; pp. 2081 - 2092
• Main Authors: GAUDREAULT, N, SCRIVEN, D. R. L, MOORE, E. D. W
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.12.2004; Springer Nature B.V
• Subjects: Animals; Biological and medical sciences; Blood vessels; Coronary vessels; Coronary Vessels - metabolism; Coronary Vessels - pathology; Diabetes; Diabetes Mellitus, Experimental - metabolism; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Endothelium; Endothelium, Vascular - metabolism; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Gene Expression Regulation; Glucose; Glucose Transporter Type 2; Humans; Hyperglycemia; Hyperglycemia - genetics; Hyperglycemia - metabolism; Image Processing, Computer-Assisted; Laboratory animals; Male; Medical sciences; Membrane Glycoproteins - metabolism; Microscopy; Monosaccharide Transport Proteins - genetics; Monosaccharide Transport Proteins - metabolism; Physiology; Protein Isoforms - metabolism; Rats; Rats, Wistar; Sodium-Glucose Transporter 1; Toxicity; Veins & arteries; Canada; Endocrinopathy; Endothelial cell; Hyperglycaemia; Rat; GLUT; Diabetes mellitus; Rodentia; Coronary artery; Fluorescence; Glucose; Long term; image analysis; Endothelial cells; Endothelium; Vertebrata; Mammalia; Animal; Glucose toxicity; SGLT; Deconvolution Digital; Streptozotocin; Carrier protein; Fluorescence microscopy
• ISSN: 0012-186X; 1432-0428
• DOI: 10.1007/s00125-004-1583-4

We have examined the effects of streptozotocin-induced type 1 diabetes on the expression and subcellular distribution of the classic sugar transporters (GLUT-1 to 5 and sodium-dependent glucose transporter-1 [SGLT-1]) in the endothelial cells of an en face preparation of septal coronary artery from Wistar rats. The presence of the GLUT isoforms and SGLT-1 in the endothelial cell layer was determined by immunohistochemistry using wide-field fluorescence microscopy coupled to deconvolution, and was quantified by digital image analysis. We found that all of the transporters were expressed within these cells and that all except SGLT-1 were preferentially located on the abluminal side. The heaviest labelling was adjacent to the cell-to-cell junctions where the luminal and abluminal membranes are in close proximity, which may reflect a spatial organisation specialised for vectorial glucose transport across the thinnest part of the cytoplasm. Long-term hyperglycaemia, induced by streptozotocin, significantly downregulated GLUT-1, 3, 4 and 5 and dramatically upregulated GLUT-2, leaving SGLT-1 unchanged. We conclude that the high susceptibility of endothelial cells to glucose toxicity may be the result of the subcellular organisation of their GLUTs and the increased expression of GLUT-2.