Cellular glucose transport disturbances as a marker of the pre-diabetic state - pathogenetic and clinical significance of the assessment of GLUT4 expression

Abstract

Introduction: GLUT4 is a representative of the family of integral membrane proteins which facilitate glucose transport across cellular membranes. In the available literature there is no publication referring to the investigations of glucotransporter expression in pre-diabetic subjects. However, GLUT4 protein overexpression was shown in leukocytes of diabetic patients. The aim of this study was to compare GLUT4 quantitative expression in peripheral blood lymphocytes in type 2 diabetes mellitus risk groups to healthy subjects.
Material and methods: The study groups included 15 pre-diabetic subjects and 15 persons with normal glucose tolerance and positive family history of type 2 diabetes mellitus (first-degree relatives). As a control group, 15 healthy persons with no family history of diabetes were enrolled. The expression of GLUT4 on the surface of peripheral blood lymphocytes was investigated with the use of indirect immunofluorescence. Quantitative determination of GLUT4 was performed with the use of flow cytometry.
Results: In the control group, GLUT4 expression amounted to 12 ± 1.5% and was significantly lower in relation to both pre-diabetic subjects (18.2 ± 8.8%; p = 0.008) and the positive family history group (17.9 ± 9%; p = 0.001).
Conclusions: GLUT4 overexpression in subjects with positive family history of type 2 diabetes mellitus suggests that cellular glucose transport disturbances occur prior to hyperglycaemia. Determination of GLUT4 expression appears to be a possibly useful method of early detection in individuals at high risk of diabetes.
(Pol J Endocrinol 2010; 61 (3): 269-274)