Author(s)

Kalpana J. Kallianpur^1,2,3*, Rasmus Birn⁴, Lishomwa C. Ndhlovu^1,5, Scott A. Souza^3,6, Brooks Mitchell³, Robert Paul⁷, Dominic C. Chow³, Lindsay Kohorn³, Cecilia M. Shikuma³

¹Department of Tropical Medicine, Medical Microbiology and Pharmacology, University of Hawaii-Manoa, Honolulu, HI, USA.
²Center for Translational Research on Aging, Kuakini Medical Center, Honolulu, HI, USA.
³Hawaii Center for AIDS, University of Hawaii-Manoa, Honolulu, HI, USA.
⁴Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA.
⁵Weill Cornell Medicine, New York, NY, USA.
⁶The Queen’s Medical Center, Honolulu, HI, USA.
⁷Missouri Institute of Mental Health, University of Missouri-St Louis, St. Louis, MO, USA.

Background: Brain atrophy and cognitive deficits persist among individuals with suppressed HIV disease. The impact of cannabis use is unknown. Methods: HIV+ and HIV- participants underwent cross-sectional magnetic resonance imaging and neuropsychological testing. Lifetime frequency, duration (years), and recency of cannabis use were self-reported. Relationships of cannabis use to resting-state functional connectivity (RSFC) and to 9 regional brain volumes were assessed with corrections for multiple comparisons. Peripheral blood cytokines and monocyte subsets were measured in the HIV+ group and examined in relation to cannabis exposure. Results: We evaluated 52 HIV+ [50.8 ± 7.1 years old; 100% on antiretroviral therapy ≥ 3 months; 83% with plasma viral load < 50 copies/mL] and 55 HIV- [54.0 ± 7.5 years old] individuals. Among HIV+ participants, recent cannabis use (within 12 months) was associated with diminished RSFC, including of occipital cortex, controlling for age. Duration of use correlated negatively with volumes of all regions (most strikingly the nucleus accumbens) independently of recent use and intracranial volume. Recent use was associated with larger caudate and white matter volumes and lower soluble vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1 concentrations. Duration of use correlated positively with psychomotor speed. Use > 10 times/lifetime was linked to more somatic symptoms, better executive function, and lower CD14⁺CD16⁺⁺ monocyte count. Conclusion: HIV+ individuals demonstrated opposing associations with cannabis. Recent use may weaken RSFC and prolonged consumption may exacerbate atrophy of the accumbens and other brain regions. More frequent or recent cannabis use may reduce the inflammation and CD14⁺CD16⁺⁺ monocytes that facilitate HIV neuroinvasion. HIV-specific cannabis studies are necessary.

Resting-State Functional Connectivity, Occipital, Atrophy, Inflammation, Monocytes

Kallianpur, K. , Birn, R. , Ndhlovu, L. , Souza, S. , Mitchell, B. , Paul, R. , Chow, D. , Kohorn, L. and Shikuma, C. (2020) Impact of Cannabis Use on Brain Structure and Function in Suppressed HIV Infection. Journal of Behavioral and Brain Science, 10, 344-370. doi: 10.4236/jbbs.2020.108022.