Cerebral metabolic dysfunction in AIDS: findings in a sample with and without dementia

Abstract

Positron-emission tomography was coupled with neurological and neuropsychological evaluation to study regional cerebral activity and neurologic status in two groups. Seventeen patients with full-blown AIDS and 14 seronegative control subjects were studied using [18F]2-fluoro-2-deoxy-D-glucose in a resting state. The AIDS group had relative regional hypermetabolism in the basal ganglia and thalamus; stepwise multiple-regression analyses revealed a significant relationship for the AIDS group between temporal lobe metabolism and severity of dementia on the AIDS Dementia Complex Rating Scale. These results suggest that the basal ganglia, thalamus, and temporal lobes are differentially affected in AIDS.

Role of nuclear medicine in neuroHIV

“…Principal component analysis of the combined (HIV-infected and controls) PET data revealed two major disease-related metabolic components: a non-specific indicator of cerebral dysfunction, which was significantly correlated with age, cerebral atrophy and HAND stage; and the striatum, which was hypermetabolic and appeared to provide a disease-specific measure of early CNS involvement [22]. Similar findings were reported by Van Gorp et al who described regional hypermetabolism in the basal ganglia and the thalamus in 17 subjects with AIDS when compared to 14 seronegative controls [23]. The authors also found a significant relationship between temporal lobe metabolism and the severity of dementia.…”

Increased Cortical Cerebral Blood Flow in Asymptomatic Human Immunodeficiency Virus-Infected Subjects

“…13, 16–18 We did not directly measure cerebral oxygen metabolism (CMRO 2 ) in this study. However, according to the equation CMRO 2 = CBF × OEF × CaO 2 , an increase in cortical gray matter CBF with no change in OEF would produce an increase in CMRO 2 unless there is a reciprocal decrease in the arterial oxygen content (CaO 2 ).…”

“…14, 15 Other studies have evaluated regional cerebral glucose metabolism using FDG PET and noted a hypermetabolic state in the deep subcortical gray matter including the basal ganglia. 16–18 Although not demonstrated in the same patients, such a resting imbalance between blood flow and metabolism could produce a state the renders the brain more susceptible to minor degrees of subsequent ischemia. A similar imbalance between resting blood flow and oxygen metabolism leading to increased oxygen extraction fraction (OEF) is associated with a marked increased risk of stroke in patients with symptomatic carotid artery occlusion.…”

Functional polymorphisms in dopamine-related genes: Effect on neurocognitive functioning in HIV+ adults

“…Reduced volume and increased blood–brain barrier permeability in the basal ganglia have also been reported (Aylward et al, 1993; Berger et al, 2000). Functional imaging studies have shown aberrant metabolism of the basal ganglia throughout the course of HIV-associated dementia, the most severe form of HAND (Hinkin et al, 1995; Rottenberg et al, 1996; van Gorp et al, 1992). Chang and colleagues (Chang et al, 2008) used positron emission tomography to show decreased dopamine transporter availability in the putamen of HIV+ individuals with HIV-associated dementia, and this correlated with a variety of neuropsychological measures.…”

“…The latter has been associated with enhanced cortical activation during cognitive tasks (Bertolino et al, 2006; Prata et al, 2009). Further, DAT is most prevalent in the striatum, an area of considerable HIV-related neuropathology (Hinkin et al, 1995; Rottenberg et al, 1996; van Gorp et al, 1992). Thus, alterations in DA availability in the striatum due to the 10-repeat allele may lead to augmentation of HIV-related neurocognitive impairment.…”