Neurometabolic profile of tobacco smoking in HIV-infected Individuals

点击翻译按钮获取中文摘要

Project Summary Tobacco smoking is a serious public health concern and is 2 to 3 times more prevalent among HIV-infected individuals than the general population. Smoking reduces the efficacy of combination antiretroviral therapy and substantially impacts the long-term survival of HIV-infected individuals. Several studies have suggested that chronic tobacco (cigarette) smoking and HIV infection have harmful additive or synergistic effects on the brain, leading to greater psychopathology, impulsivity and cognitive dysfunction. Little is known about the neurochemical profile related to the combined effects of HIV infection and smoking. HERCULES is a novel J- difference-edited magnetic resonance spectroscopy (MRS) technique that can measure up to seven low- concentration brain metabolites (e.g., GABA) with relatively short scan times. However, HERCULES is sensitive to subject motion, which affects both localization accuracy and spectral quality. Both HIV-infected subjects and tobacco smokers have greater impulsivity that might lead to greater subject motion. Therefore, the aims of this project are: 1) K99 phase: the candidate will be mentored in the development of the motion-corrected HERCULES sequence, which will allow robust investigation of these neurometabolites; he will also assess the reproducibility of HERCULES with and without motion correction in seronegative (SN) healthy controls; 2) K99 phase: to learn to conduct a pilot clinical study using the optimized motion-corrected HERCULES to evaluate the neurometabolic profile of HIV-infected individuals or tobacco smokers, compared to SN healthy controls; 3) R00 phase: to measure a comprehensive neurochemical profile in four groups of individuals (SN/tobacco-, HIV+/tobacco-, SN/tobacco+, HIV+/tobacco+), using the motion-corrected HERCULES sequence. Based on the proposed clinical training and didactic courses, the candidate will work with experienced globally recognized experts in the fields of MRS and clinical HIV research to achieve five training goals: (1) develop expertise in research design and clinical assessments of HIV-infected individuals and tobacco smokers; (2) conduct a pilot study to evaluate the independent effects of HIV and tobacco smoking on neurometabolite levels; (3) learn to apply an advanced MRS technique to clinical research, especially in HIV+ individuals and tobacco smokers; and (4) learn to apply advanced statistical methods to analyze complex clinical data from patient populations. The long-term career objective of the candidate is to become an independent scientist with a complete repertoire of skills in MRS methodologies and their clinical applications. The motion-corrected HERCULES can be applied to study metabolic processes in other diseases as well, adding scope and impact to this research proposal, which is also responsive to NIDA’s mission of “strategically supporting and conducting basic and clinical research on drug use (including nicotine), its consequences, and the underlying neurobiological mechanisms involved.”