20 - Transport of Cytokines and Neurotrophins across the Blood-Brain Barrier and Their Regulation after Spinal Cord Injury

Abstract

Cytokines and neurotrophic peptides/proteins have various degrees of permeation across the blood–brain barrier (BBB) by simple diffusion or by specific transport systems. The transport systems are significant because of the biological impact of these molecules on the central nervous system (CNS) in health and disease. Identification of BBB permeation and the modulating factors aid in the application of the cytokines and neurotrophic peptides/proteins as therapeutic agents. This chapter discusses the spinal cord injury (SCI) in detail. SCI is related to time and region-specific changes of the BBB function. After SCI, the increase in the entry of TNF-a to the CNS differs from leakage after BBB disruption and is related to upregulation of the transport system in a unique temporal and regional pattern. In this way, SCI at different locations with different types and severity of lesions is associated with different patterns of upregulation of the transport system. Thus it indicates that the BBB is a dynamic barrier that regulates the availability of cytokines and neurotrophic peptides/proteins to the CNS in normal physiological conditions, and that the BBB is also modulated by pathological processes such as SCI.