Neurological and psychiatric adverse effects of antiretroviral drugs

Involvement of nitric oxide in the mitochondrial action of efavirenz: a differential effect on neurons and glial cells

The anti-human immunodeficiency virus (HIV) drug efavirenz (EFV) alters mitochondrial function in cultured neurons and glial cells. Nitric oxide (NO) is a mediator of mitochondrial dysfunction associated with HIV central nervous system symptoms. We show that EFV promotes inducible nitric oxide synthase (iNOS) expression in cultured glial cells and generated NO undermines their mitochondrial function, as inhibition of NOS partially reverses this effect. EFV inhibits mitochondrial Complex I in both neurons and glia; however, when the latter cells are treated for longer periods, other mitochondrial complexes are also affected in accordance with the increased NO production. These findings shed light on the mechanisms responsible for the frequent EFV-associated neurotoxicity.

Imaging neuroinflammation? A perspective from MR spectroscopy

Neuroinflammatory mechanisms contribute to the brain pathology resulting from human immunodeficiency virus (HIV) infection. Magnetic resonance spectroscopy (MRS) has been touted as a suitable method for discriminating in vivo markers of neuroinflammation. The present MRS study was conducted in four groups: alcohol dependent (A, n = 37), HIV-infected (H, n = 33), alcohol dependent + HIV infected (HA, n = 38) and healthy control (C, n = 62) individuals to determine whether metabolites would change in a pattern reflecting neuroinflammation. Significant four-group comparisons were evident only for striatal choline-containing compounds (Cho) and myo-inositol (mI), which follow-up analysis demonstrated were due to higher levels in HA compared with C individuals. To explore the potential relevance of elevated Cho and mI, correlations between blood markers, medication status and alcohol consumption were evaluated in H + HA subjects. Having an acquired immune deficiency syndrome (AIDS)-defining event or hepatitis C was associated with higher Cho; lower Cho levels, however, were associated with low thiamine levels and with highly active antiretroviral HIV treatment (HAART). Higher levels of mI were related to greater lifetime alcohol consumed, whereas HAART was associated with lower mI levels. The current results suggest that competing mechanisms can influence in vivo Cho and mI levels, and that elevations in these metabolites cannot necessarily be interpreted as reflecting a single underlying mechanism, including neuroinflammation.

Efavirenz induces neuronal autophagy and mitochondrial alterations

Efavirenz (EFV) is a non-nucleoside reverse-transcriptase inhibitor in wide use for the treatment of human immunodeficiency virus infection. Although EFV is generally well tolerated, neuropsychiatric toxicity has been well documented. The toxic effects of EFV in hepatocytes and keratinocytes have been linked to mitochondrial perturbations and changes in autophagy. Here, we studied the effect of EFV on mitochondria and autophagy in neuronal cell lines and primary neurons. In SH-SY5Y cells, EFV induced a drop in ATP production, which coincided with increased autophagy, mitochondrial fragmentation, and mitochondrial depolarization. EFV-induced mitophagy was also detected by colocalization of mitochondria and autophagosomes and use of an outer mitochondrial membrane tandem fluorescent vector. Pharmacologic inhibition of autophagy with 3-methyladenine increased the cytotoxic effect of EFV, suggesting that autophagy promotes cell survival. EFV also reduces ATP production in primary neurons, induces autophagy, and changes mitochondrial morphology. Overall, EFV is able to acutely induce autophagy and mitochondrial changes in neurons. These changes may be involved in the mechanism leading to central nervous system toxicity observed in clinical EFV use.

HIV associated neurocognitive disorders (HAND) in Malawian adults and effect on adherence to combination anti-retroviral therapy: a cross sectional study

BACKGROUND

Little is known about the prevalence and burden of HIV associated neurocognitive disorder (HAND) among patients on combination antiretroviral therapy (cART) in sub-Saharan Africa. We estimated the prevalence of HAND in adult Malawians on cART and investigated the relationship between HAND and adherence to cART.

METHODS

HIV positive adults in Blantyre, Malawi underwent a full medical history, neurocognitive test battery, depression score, Karnofsky Performance Score and adherence assessment. The Frascati criteria were used to diagnose HAND and the Global Deficit Score (GDS) was also assessed. Blood was drawn for CD4 count and plasma nevirapine and efavirenz concentrations. HIV negative adults were recruited from the HIV testing clinic to provide normative scores for the neurocognitive battery.

RESULTS

One hundred and six HIV positive patients, with median (range) age 39 (18-71) years, 73% female and median (range) CD4 count 323.5 (68-1039) cells/µl were studied. Symptomatic neurocognitive impairment was present in 15% (12% mild neurocognitive disorder [MND], 3% HIV associated dementia [HAD]). A further 55% fulfilled Frascati criteria for asymptomatic neurocognitive impairment (ANI); however factors other than neurocognitive impairment could have confounded this estimate. Neither the symptomatic (MND and HAD) nor asymptomatic (ANI) forms of HAND were associated with subtherapeutic nevirapine/efavirenz concentrations, adjusted odds ratio 1.44 (CI. 0.234, 8.798; p = 0.696) and aOR 0.577 (CI. 0.09, 3.605; p = 0.556) respectively. All patients with subtherapeutic nevirapine/efavirenz levels had a GDS of less than 0.6, consistent with normal neurocognition.

DISCUSSION/CONCLUSION

Fifteen percent of adult Malawians on cART had a diagnosis of MND or HAD. Subtherapeutic drug concentrations were found exclusively in patients with normal neurocognitive function suggesting HAND did not affect cART adherence. Further study of HAND requires more robust locally derived normative neurocognitive values and determination of the clinical relevance of ANI.

Cellular Interactions and Signaling in neuroAIDS: Emerging Issues Colloquium

On May 23, 2013 scientific leaders in the neuroAIDS community met at the University of Nebraska Medical Center to discuss cellular interaction and signaling for the third annual human immunodeficiency virus and neuroAIDS colloquium. The meeting continues a series of contemporary scientific issues related to how virus effects the nervous system. In 2011 the focus was on animal models and in 2012 in biomarkers. Here, our 2013 meeting featured ten presentations from outstanding scientists examining how inter- and intra-cellular processes contribute to neuropathogenesis. Talks highlighted emerging issues, findings, and potential therapies, followed by a panel discussion in which controversies in the field and gaps in our current knowledge were identified. The panel discussion was transcribed into the article and published as a field perspective. A link is available where all of the presentations and the concluding discussion can be seen and heard. The third annual University of Nebraska Medical Center (UNMC) colloquium on current issues in neuroAIDS was held on May 23, 2013. Following the presentations, which can be viewed at http://www.unmc.edu/pharmacology/CISN.htm . A panel discussion ensued. This discussion raised important topical issues. To disseminate this information, a transcript is provided below.