A simulation of recreational and addictive methamphetamine use on the integrity of the blood-brain barrier endothelium using an in vitro BBB model

Methamphetamine (Meth) is a widely abused psychostimulant implicated in severe neuropathologies, such as hemorrhagic stroke, which arises from disruptions to the blood-brain barrier (BBB). The selectively permeable BBB, composed primarily of brain microvascular endothelial cells (BMVECs) forms the cerebral capillaries and serves as the brain's protective interface against circulating toxins and pathogens. Despite its recognized susceptibility to Meth, the direct effects of Meth exposure on BMVECs remain insufficiently understood. To model the two types of Meth users, recreational and addictive, bEnd.5 cells were exposed to Meth for 24 hours only or daily. Changes in cellular division, mitochondrial activity, cellular morphology, and barrier integrity were assessed using the trypan blue exclusion assay, XTT, Hematoxylin and Eosin (H&E) stain, and transendothelial electrical resistance (TEER), respectively. Acute Meth exposure suppressed cellular division and reduced Mitochondrial activity (MA) in a 24-hour oscillatory manner, while chronic Meth exposure induced a sustained suppression of cellular division. Morphological analyses revealed nuclear abnormalities consistent with mitotic disruption. Both exposure conditions reduced endothelial monolayer integrity over the 96-hours; however, chronic exposure caused exacerbated decreases in barrier integrity. Notably, even acute Meth exposure was sufficient to initiate long-term BBB endothelium dysfunction. These findings demonstrate a continuum of BBB vulnerability arising from both recreational and addictive Meth use, underscoring the critical need for early intervention to avert progressive cerebrovascular, hemorrhagic, and neurological damage.