The immature endothelial cell in new vessel formation following surgical injury in rat brain.

OBJECTIVES: We investigated neovasculatization in the cerebral cortex of the adult rat after surgical brain injury by ultrastructural, immunocytochemical and immunochemical means. Previously we described endothelial-like cell that participates in new vessel formation on plasma proteins that served as a provisional matrix in the region immediately adjacent to the traumatic injury. In the present study we describe new vessel formation in the multistep process with the alterations in endothelial-like cell immunophenotype.

METHOD: The observations were conducted from 2 to 7 days after induction of cortical trauma. Traumatic injury was induced in the frontotemporal region of cerebral cortex.

RESULTS: We show that endothelial-like cell could not successfully terminate its development without the presence of pericyte and astrocyte. New formed blood vessels were accompanied by fibroblast and lipofibroblast cells differentiated probably from common progenitor.

MAIN FINDINGS: Our result suggests that endothelial-like cell is committed endothelial cell between progenitor endothelial cell and terminally differentiated endothelium stage. Therefore, we propose that our of endothelial stem cells present in blood at different stages of morphogenetic differentiation and specifically arrested in "check points" of development trauma mobilize the group of the most differentiated progenitors. These may contribute to new vessel formation.

CONCLUSION: Our model should be useful for the characterization of endothelial commitment and endothelial cell differentiation after brain injury.

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