Cd34-positive developing vessels and other structures in human fetuses: an immunohistochemical study

Abstract

CD34 is a well-known marker of progenitor cells of blood vessels and stromal tissues. Thus, CD34-positive cells have recently been used clinically in the field of vascular and orthopedic biotechnology because of their capacity to assist regeneration of injured tissues. However, to our knowledge, the in situ distribution of CD34-positive cells has not yet been described in the human fetus, with the exception of a few organs. In the present study, we conducted immunohistochemistry for CD34 using 12 human fetuses (9-15 weeks of gestation). CD34-positive structures showed a vessel-like appearance and were regularly arrayed in the viscera, nerves and lymph nodes, whereas in the body wall and extremities, they were distributed diffusely as fibrous tissues, such as the fascia and perimysium. The myocardium was also divided and bundled by CD34-positive fibrous tissues. In striated muscles, limited examples of CD34 expression were found in the tongue and extraocular muscles in which only vessels were positive. Lymphatic vessels were negative for CD34. In addition to their contribution to vascular development in any part of the body, CD34-positive mesenchymal tissues seem to play a critical role in the pattern formation of skeletal muscle, synovial tissue and other muscle/tendon-associated tissues in human fetuses.

Immunohistochemical Heterogeneity of the Endothelium of Blood and Lymphatic Vessels in the Developing Human Liver and in Adulthood

“…Almost identical immunoreactivity is evident for CD31 molecules, the difference being that, on the endothelium, it expresses slightly later than that of CD34. Abe et al [2011] described CD34-immunopositive endothelium of the portal vein branches and CD34-immunonegative endothelium of the hepatic vein tributaries. As for the CD34 immunoreactivity of the endothelial sinusoids, our results are consistent with their findings; they partly described CD34-positive endothelial cells in sinusoids in the 15th week of development.…”

“…Lalor et al [2006] contend that CD31 immunoreactivity in the endothelium of hepatic sinusoids is present only after 25 weeks of development. Abe et al [2011] indicate that CD34 is positively expressed on the endothelial cells of sinusoids starting from 15 weeks of development.…”

D2-40 Immunoreactivity of Lymphatic Vessels Endothelium and Representation of Lymphatic Vessels in the Liver of Human Fetuses of Different Gestational Age

“…Endothelium is a common structural component of lymph vessels and sinusoids of the liver, but during embryonal development it differentiates into two morphologically and functionally different epithelial lines characterized by the expression of different molecules -endothelial cells in the liver sinusoids express, above all, CD31 and CD34 molecules (16,17), while endothelial cells of the lymph vessels express LYVE-1 (8,18,19) and D2-40 molecules (20,21).…”

Anatomical and histological study of human deep fasciae development

“…At an embryological level, the deep fascia surrounding the developing muscles has been referred to as mesenchymal undifferentiated connective tissue [1,12]. Accordingly, Tcf4-positive fibroblasts in mesenchymal connective tissue have been described as a key factor in muscle morphogenesis in developmental mouse and chick models [6,9].…”