AUTHOR=Gostner Johanna M. , Becker Kathrin , Kurz Katharina , Fuchs Dietmar TITLE=Disturbed Amino Acid Metabolism in HIV: Association with Neuropsychiatric Symptoms JOURNAL=Frontiers in Psychiatry VOLUME=6 YEAR=2015 URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2015.00097 DOI=10.3389/fpsyt.2015.00097 ISSN=1664-0640 ABSTRACT=

Blood levels of the amino acid phenylalanine, as well as of the tryptophan breakdown product kynurenine, are found to be elevated in human immunodeficiency virus type 1 (HIV-1)-infected patients. Both essential amino acids, tryptophan and phenylalanine, are important precursor molecules for neurotransmitter biosynthesis. Thus, dysregulated amino acid metabolism may be related to disease-associated neuropsychiatric symptoms, such as development of depression, fatigue, and cognitive impairment. Increased phenylalanine/tyrosine and kynurenine/tryptophan ratios are associated with immune activation in patients with HIV-1 infection and decrease upon effective antiretroviral therapy. Recent large-scale metabolic studies have confirmed the crucial involvement of tryptophan and phenylalanine metabolism in HIV-associated disease. Herein, we summarize the current status of the role of tryptophan and phenylalanine metabolism in HIV disease and discuss how inflammatory stress-associated dysregulation of amino acid metabolism may be part of the pathophysiology of common HIV-associated neuropsychiatric conditions.