Fibrotic Scar in CNS Injuries: From the Cellular Origins of Fibroblasts to the Molecular Processes of Fibrotic Scar Formation

Central nervous system (CNS) trauma activates a persistent repair response that leads to fibrotic scar formation within the lesion. This scarring is similar to other organ fibrosis in many ways; however, the unique features of the CNS differentiate it from other organs. The glial scar, unique in CNS injuries, is mainly formed by reactive astrocytes, which are characterized by the increased expression of glial fibrillary acidic protein (GFAP), hypertrophy, and the extension of processes. This review focuses on the current knowledge surrounding the pathogenesis of fibrosis following trauma to the CNS. We will discuss the cellular origins of fibroblasts, their spatial and temporal distribution, the mechanism of fibrotic scar formation, and the pathological roles of the fibrotic scar.

• 1
  Meningeal fibroblasts have long been shown to play a role in the fibrotic scar formation in CNS trauma after migrating into the lesion through the torn meninges.
• 2
  Perivascular fibroblasts are located in the perivascular space and are loosely attached to the larger blood vessels in the CNS but are absent from the capillaries.
• 3
  A subpopulation of pericytes, known as Type A pericytes, has been suggested as fibroblasts’ origin in pathological scarring after SCI, TBI, and EAE.