15th International AIDS Conference Bangkok, Thailand - July 11-16, 2004

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. ThOrA1408)

Arendt G, Haslinger BA, Koller H, von Giesen HJ, Antke C, Wittsack HJ
Department of Neurology, University Hospital of Duesseldorf, Duesseldorf, Germany

BACKGROUND: Neuropathogenesis of HIV-1-infection is not yet totally clarified. During the last years, there have been achieved advances, for example, growing knowledge on CCR5 co-receptor use of the thus called R5 virus variants. But the relevant molecular mechanisms are not yet understood. The question is, whether neuro-imaging procedures could contribute to an "in vivo" analysis.

METHODS: In 2346 HIV-1-positive individuals - consecutively recruited since 1987 - cranial magnetic resonance tomographies (MRI) and their predictive value for disease progression were analysed. In subgroups (n = 19, n = 32 and n = 10) positron emission tomography (PET), magnetic resonance spectroscopy (MRS) and single photon emission computer tomography (SPECT) were performed; cerebral glucose metabolism (PET), glial and neuronal cell markers (MRS) as well as D-receptor function (SPECT) were examined.

RESULTS: Whereas structural imaging procedures (MRI) revealed unspecific abnormalities late in the clinical course of HIV-1-related brain disease, PET results showed hints on the kinetics of HIV-1-associated encephalopathy and its precursor symptoms as well as MRS detected up-regulation of glial cell markers in early and down-regulation of neuronal markers in late HIV-1-related brain disease. Early abnormalities are seen predominantly in the basal ganglia supposed to have a "pace-maker" function in HIV-1-associated brain disease. SPECT results pointed to irritations of dopamine synthesis or release, whereas receptor function and active transport seem to be unaffected.

CONCLUSIONS: Thus, conventional imaging procedures are not the right tool for research on virus associated brain disease, whereas functional imaging (PET and MRS) methods characterise subgroups of patients with early subclinical cerebral deficits. SPECT procedures give hints for the most irritated brain regions. Finally, molecular imaging techniques could be the right method for evaluating the molecular mechanisms destroying the brain in this devastating and disabling dise ase in relatively young patients.

040711
ThOrA1408

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