Connective tissue growth factor is expressed by a subset of reactive astrocytes in human cerebral infarction

Connective tissue growth factor (CTGF) a transforming growth factor (TGF)-β₁ downstream mediator, is a secreted cell matrix-inducing peptide involved in both tissue regeneration mechanisms, such as wound repair and also in aberrant deposition of extracellular matrix. The present study reports CTGF expression by cells associated with matrix deposition and glial scar formation in human cerebral infarction. CTGF was localized by immunohistochemistry in 17 brains of patients after focal infarction and in three neuropathologically normal control brains. CTGF expression was selectively localized to the cytoplasm of stellate reactive astrocytes. Compared to peripheral areas and brain controls without neuropathological findings, the total number CTGF⁺ astrocytes was significantly higher (P<0.0001) in border zones adjacent to the core, corresponding to the penumbra. These numbers were significantly increased at day 1 and day 3 and remained persistently elevated up to several months post-infarction (P<0.0001). The restricted expression and accumulation of CTGF⁺ reactive astrocytes adds convincing evidence for CTGF participation in the gliotic astrocyte CNS injury response involved in glial scar formation. CTGF can be considered a sensitive marker of early human astrocyte activation and a possible target for pharmacological intervention of aberrant matrix deposition.