On the developmental origin of hepatic sinusoidal endothelium: confirmation of angiocirculatory vasculogenesis

Abstract

Developmental mechanisms reported to account for the origin of hepatic sinusoidal endothelium include (1) in situ differentiation of mesenchymal cells (Sherer, 1991), (2) sprouting from preexisting vessels (Gouysse et al., 2002), (3) transdifferentiation of mesothelial cells (Pérez‐Pomares et al., 2004), and (4) recruitment of angioblasts and/or vascular endothelial cells (VECs) from the circulation (Pardanaud & Eichmann, 2006; Zhang et al., 2006). The present study was designed to investigate whether the last of these mechanisms, here termed angiocirculatory vasculogenesis, plays a role in the development of hepatic sinusoidal endothelium. Chick livers were harvested from quail/chick parabioses maintained either in ovo or in shell‐less culture and were examined for evidence of quail VECs by immunostaining with QH1 antibody. Numerous positively‐stained cells were found to contribute to the sinusoids of parabiotic chick livers. Non‐parabiotic chick liver, serving as a negative control, lacked staining. These findings confirm that at least some of the cells that form these capillary‐level vascular structures are, as previously reported, acquired from circulating blood.Grant Funding Source: None