Human dental pulp vasculogenesis evaluated by CD34 antigen expression and morphological arrangement

Vasculogenesis describes the process by which endothelial precursor cells form new blood vessels. To characterize the topography and the cellular processes underlying vascularization of human dental pulp, we examiend the expression of the human hematopoietic progenitor cell antigen CD34. Dental pulps, obtained from deciduous and permanent teeth, were morphologically examined at light- and electron-microscope levels and by expression of CD34. The findings indicate that vasculogenesis of dental pulp is a complicated process starting from single CD34(+) cells. These subsequently coalesce to form solid vascular cords inside the developing connective tissue, which later hollows. Pericytes were embedded within the fully formed microvessels' basement membrane. The presence of CD34(+) endothelial cells in permanent teeth reveals that the process of vasculogenesis persists into adult life, where it contributes to continuous adjustment of vessel and network structures in response to functional needs and dental tissue homeostasis.