Impact of Obstructive Sleep Apnea on Blood–Brain Barrier Permeability and Membrane Proteins

The blood-brain barrier (BBB) carefully regulates the transport of molecules between the blood and the nervous tissue. Obstructive sleep apnea (OSA) is a chronic condition that induces structural and functional changes in the BBB. These include alterations in its permeability and in protein expression in the BBB capillary endothelium. Moreover, OSA alters blood levels of transcription factors, such as hypoxia-inducible factor 1 (HIF-1), which are suggested to be responsible for these changes. As a review article, this paper focuses on the most significant effects of OSA on the BBB, including deviations in barrier morphology, particularly changes in the expression of tight junction and adherens junction proteins and membrane channels, as well as their impact on transport across the barrier. Moreover, particular attention is given to emerging evidence for the differential regulation of major BBB efflux transporters, including P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), as well as the role of the HIF-1 pathway. Additionally, we summarize the current state of knowledge regarding the contribution of these BBB alterations to the development of neurodegenerative diseases. At the same time, altered transport is being investigated as a possibility for delivering new drugs to the central nervous system. Thus, this review aims to summarize the current knowledge about OSA's impact on the BBB.