HIV and chronic methamphetamine dependence affect cerebral blood flow

Abstract

Human immunodeficiency virus (HIV) and methamphetamine (METH) dependence are independently associated with neuronal dysfunction. The coupling between cerebral blood flow (CBF) and neuronal activity is the basis of many task-based functional neuroimaging techniques. We examined the interaction between HIV infection and a previous history of METH dependence on CBF within the lenticular nuclei (LN). Twenty-four HIV-/METH-, eight HIV-/METH+, 24 HIV+/METH-, and 15 HIV+/METH+ participants performed a finger tapping paradigm. A multiple regression analysis of covariance assessed associations and two-way interactions between CBF and HIV serostatus and/or previous history of METH dependence. HIV+ individuals had a trend towards a lower baseline CBF (-10%, p = 0.07) and greater CBF changes for the functional task (+32%, p = 0.01) than HIV- subjects. Individuals with a previous history of METH dependence had a lower baseline CBF (-16%, p = 0.007) and greater CBF changes for a functional task (+33%, p = 0.02). However, no interaction existed between HIV serostatus and previous history of METH dependence for either baseline CBF (p = 0.53) or CBF changes for a functional task (p = 0.10). In addition, CBF and volume in the LN were not correlated. A possible additive relationship could exist between HIV infection and a history of METH dependence on CBF with a previous history of METH dependence having a larger contribution. Abnormalities in CBF could serve as a surrogate measure for assessing the chronic effects of HIV and previous METH dependence on brain function.

Fig. 1

Schematic of magnetic resonance imaging scan and functional task paradigm performed by each subject. Activated voxels within the lenticular nuclei (LN) are highlighted in red. b Cerebral blood flow (CBF) time course for functional task

Fig. 2

Changes in CBF and volume for HIV−/METH−, HIV−/METH+, HIV+/METH− and HIV+/METH+ groups. a Baseline CBF was significantly higher for HIV−/METH− subjects compared to all other groups. b HIV−/METH− subjects had a significantly lower magnitude in the CBF changes for a functional task compared to all other groups. c Absolute total CBF changes were similar for all groups with reductions in baseline CBF cancelling out increases in changes in CBF for a functional task. d Absolute LN volumes were similar for all groups. For all boxplots, the top and bottom of the box are the 25th and 75th percentiles. The length of the box is the interquartile range (IQR). The line through the middle of the box is the median (the 50th percentile). The T-shaped lines that extend from each end of the box represent the minimum and maximum of all the data