Lesional expression of the endogenous angiogenesis inhibitor endostatin/collagen XVIII following traumatic brain injury (TBI)

We have analysed the expression of the endogenous angiogenesis inhibitor endostatin/collagen XVIII following stab wound injury and observed a highly significant (p < 0.0001) lesional accumulation confined to areas of pan-necrotic injury and developing secondary damage. Maximal cell numbers were detected at Day 14, declining until Day 21 after injury. Further, endostatin/collagen XVIII+ monocytic cells accumulated in Virchow-Robin spaces where they formed cell clusters. Besides being prevailingly localised to ED1+ activated microglia/macrophages, endostatin/collagen XVIII expression was also detected by subendothelial surrounding vessels in the lesioned area. Late and prolonged accumulation of endostatin/collagen XVIII+ microglia/macrophages and increased numbers of endostatin/collagen XVIII+ subendothelial cells/vessels in areas of vascular pruning and regression, point to a role in the termination of the transient angiogenic response, linked to a “late” inflammatory milieu.