Chapter 20 - Chitinase-3-like protein 1: Features and applications as a biomarker in traumatic brain injury

Abstract

Biomarkers in traumatic brain injury (TBI) have been explored for their potential to provide reliable and quantitative information regarding the pathophysiological mechanisms underlying observed neurological deficits. However, those currently accepted in the neurotrauma field do not come without their limitations. Recently, pronounced expression of a novel biomarker, chitinase-3-like protein 1 (CHI3L1), also known as YKL-40 in humans and breast regression protein 39 (BRP-39) in rodents, that is associated with pre-clinical models and patients after TBI has been identified. CHI3L1 overexpression was identified in astrocytes restricted to the traumatic penumbra after experimental brain contusion. Additionally, chi3l1 knockout (KO) mice have been employed to elucidate the involvement of this protein in the neuropathology of TBI. In recent years, CHI3L1 has been increasingly proposed as a sensitive biomarker and an important component of the astrocytic response modulating neuroinflammation. For this reason, in this chapter, we review the plausible roles and mechanisms of CHI3L1 in the pathogenesis of TBI, as well as its usefulness as a potential candidate biomarker from both diagnostic and therapeutic standpoints.