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Stimulant and opioid dependence effects on enlarged perivascular spaces in a marginalized population Hamzah, Yasmin


Enlarged perivascular spaces (EPVS) are markers of cerebral small vessel (CSVD) disease, the most common cause of vascular dementia. Risk factors of EPVS are age, hypertension, lacunes, and microbleeds. Although the etiology of EPVS is unclear, these risk factors point to different mechanisms of origin, specifically inflammation and dysfunction in the blood-brain barrier. A marginalized population with multi-morbid dependence, increased prevalence of head trauma, and psychiatric disorders had a higher cerebral small vessel disease incidence than the general population. Given this high incidence of substance use and cerebral small vessel disease, examining potential drug effects on EPVS is of interest. Because stimulant dependence increases the risk of hypertension and opioids can induce hypotension, we grouped participants by substance dependence categories based on their varying blood pressure effects. These three categories were participants with 1) stimulant dependence, 2) stimulant and opioid dependence, and 3) no or opioid dependence. Due to the high rates of polysubstance use in this population, other non-opioid and non-stimulant drug dependences such as cannabis were included within each of the three drug groupings. T1 MRI brain images and their associated current drug dependence group were analyzed to determine opioid and stimulant effects on EPVS while controlling for covariates. Enlarged perivascular spaces were tabulated in the centrum semiovale, basal ganglia, midbrain, and hippocampi. Four statistical models were analyzed, one for each brain region of interest. Age was used as a covariate in all models because it obeyed all ANCOVA assumptions in all regions of interest. Sex was used as a covariate in the centrum semiovale only as this was the only region sex followed ANCOVA assumptions. Other covariates did not follow assumptions. There was a significant difference between drug groups in the hippocampus. Post-hoc Bonferroni analysis in the hippocampus revealed the no/opioid dependence group had a more significant EPVS burden than the other two groups containing participants who were dependent on stimulants. Results suggest opioid dependence causes significantly more EPVS burden than stimulants in the hippocampus. Future studies should focus on isolating drug effects for greater insight into the relationship between stimulants/opioids and EPVS.

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