OBJECTIVE: To determine the role of tenascin-C in fetal hepatic hematopoietic proliferation and differentiation in different stages of development.
STUDY DESIGN: We examined and compared the immunohistochemical expression of tenascin-C in the hepatic stromal portal fields in the first, second, and third trimester of gestation respectively, in relation to the appearance of CD34 progenitor hematopoietic, stromal progenitor and vascular endothelial positive cells.
RESULTS: Our results demonstrated a quantitative difference in the second trimester of gestation concerning the expression of tenascin-C in the connective tissue stroma of the hepatic portal fields over the equivalent expression of the protein in the first (P<0.0001, t-test) and third trimester (P<0.0001, t-test). Similar changes in the above period were found concerning the expression of CD34 over the first (P<0.0001, t-test) and third trimesters (P<0.0001, t-test), suggesting a direct involvement of tenascin-C in the sustaining of hematopoietic activity.
CONCLUSIONS: Our data provide evidence that an ECM glycoprotein component, tenascin-C, plays a relevant role in hematopoiesis through interaction between stromal cells and hematopoietic progenitor cells.