Cerebral glucose transporter expression in HIV infection

Abnormalities in cerebral glucose metabolism have been demonstrated in patients with AIDS dementia complex (ADC), with increased consumption in early disease and decreased utilization in late stages. The basis of these changes is unknown. Accordingly, a pilot study was undertaken to determine whether levels of cerebral glucose transporters GLUT1 and GLUT3 were altered by HIV disease. Frontal gray and white matter membrane preparations from patients with HIV encephalitis (HIVE), HIV infection without parenchymal neuropathology, and noninfected controls were utilized in quantitative immunoblots to measure GLUT1 and GLUT3. Results were expressed as a ratio of glucose transporter to structural protein actin. Within-group patient variability was great, precluding statistically significant differences between groups for any one brain region. However, when data for gray and white matter was pooled, results obtained statistical significance, with levels of GLUT1 increasing in HIV infection without neuropathology, and declining with HIVE. Increased GLUT1 in HIV infection without parenchymal neuropathology may be important in the biology of increased glucose consumption described with early ADC. With progression to HIVE, reduced levels of glucose transporters may contribute to late stage hypometabolism.