Thrombospondin in early human wound tissue.

We examined partial thickness incised human wounds of 2, 3, 5, 7, and 14 days of age for the presence of thrombospondin by immunostaining and light microscopy. At 2, 3, 5, and 7 days after wounding, thrombospondin is present primarily at the cut edges of the lateral and deep margins of the wound. It appears to be cleared from these extracellular matrix sites, and is no longer detectable in those sites in most 14-day-old wounds. Thrombospondin staining is present, however, in increased amounts around the vascular channels within and adjacent to the 7- and 14-day wounds in increased amounts relative to vascular channels distant from the wound. Our observations are consistent with known in vitro data regarding the binding of thrombospondin to fibrin and components of the extracellular matrix, as well as with data showing that proliferating endothelial cells secrete more thrombospondin than quiescent endothelial cells. These data support the hypothesis that thrombospondin plays a role in the early organization of the extracellular matrix of wounds.