An estimated 26 million people abuse methamphetamine (meth) worldwide. This high prevalence of abuse and the ensuing health and societal consequences necessitates a clear need to understand the long-term neural and vascular adaptations caused by chronic meth that contribute to addiction and relapse. Meth exposure interferes with the neuronal and vascular function required to establish connectivity and wiring of interconnected networks. An integral part of vascular-neural coupling, the blood brain barrier (BBB), is particularly sensitive to inflammatory mechanisms and BBB health reflects the general health of neurovascular crosstalk. Acute exposure to high doses of meth results in neuroinflammation and subsequent increases in BBB permeability. However, the long-term consequence of chronic meth-induced neuroinflammation on neurovascular health is an understudied area of meth addiction. Notably, these issues have not been addressed using a clinically relevant rodent model of meth addiction. Our central hypothesis is that chronic self-administered meth results in lasting neuroinflammation that compromises neural-vascular coupling of the BBB. To test this hypothesis, we will use cutting edge magnetic resonance based neuroimaging techniques to identify the progression of inflammation following prolonged meth self-administration. These inflammatory responses may be early indicators for meth-induced damage to neurovascular units and subsequent break down of the BBB. We will measure the time course of meth-induced changes in neuronal and vascular integrity during abstinence from meth by measuring white matter integrity and BBB transfer rate to map progressive tissue damage. These assessments are not possible by relying solely on histological outcomes. Therefore, the end point results will be correlated with histological outcomes on endothelial and inflammatory markers. The imaging experiment is designed to acquire information about spatial and temporal patterns of damage to neurovascular unit providing valuable information on the progression of meth-induced adaptations. Further, this study will provide novel information for diagnostic and treatment planning for meth addiction.
Escalating meth use worldwide creates an enormous financial and health burden on families and society, meriting the need for successful treatment outcomes;however, success is hindered by limited knowledge of chronic meth-induced neural adaptations in human and animal models. Understanding the collective dynamics of the neurovascular response to chronic meth exposure is important for treatment planning and reversal of persistent damage. The use of in vivo neuroimaging techniques combined with a well-validated animal model of meth addiction will result in high translationally relevant outcomes for diagnostic and treatment planning.