Dexmedetomidine enhances glymphatic brain delivery of intrathecally administered drugs.

Drug delivery to the central nervous system remains a major problem due to biological barriers. The blood-brain-barrier can be bypassed by administering drugs intrathecally directly to the cerebrospinal fluid (CSF). The glymphatic system, a network of perivascular spaces promoting fluid exchange between CSF and interstitial space, could be utilized to enhance convective drug delivery from the CSF to the parenchyma. Glymphatic flow is highest during sleep and anesthesia regimens that induce a slow-wave sleep-like state. Here, using mass spectrometry and fluorescent imaging techniques, we show that the clinically used α 2 -adrenergic agonist dexmedetomidine that enhances EEG slow-wave activity, increases brain and spinal cord drug exposure of intrathecally administered drugs in mice and rats. Using oxycodone, naloxone, and an IgG-sized antibody as relevant model drugs we demonstrate that modulation of glymphatic flow has a distinct impact on the distribution of intrathecally administered therapeutics. These findings can be exploited in the clinic to improve the efficacy and safety of intrathecally administered therapeutics. Unlabelled Image • The glymphatic system drives cerebrospinal fluid influx into brain tissue. • Glymphatic flow is increased by drugs that decrease brain noradrenergic tone. • Dexmedetomidine is a clinically used α 2 -adrenergic agonist sedative. • Dexmedetomidine increases the brain delivery of intrathecally administered drugs. • Glymphatic flow can be manipulated to enhance the CNS delivery of intrathecal therapeutics. [ABSTRACT FROM AUTHOR]