Histopathology and Ultrastructure of Human Umbilical Blood Vessels

Abstract

To resolve controversy over umbilical vessels structure, a morphological review was undertaken of the histology of blood vessels in 130 fetal umbilical cords varying in gestational age and the ultrastructure of blood vessels in 6 umbilical cords. Arteries and veins were lined by endothelium. The internal elastic lamina was frequently interrupted when associated with intimal thickening of longitudinally orientated smooth muscle cells. Fragments of elastic laminae developed in the intima and inner media both of which were thicker in arteries than in vein. No external elastic laminae or distinct adventitia were found. Most notable was the accumulation of cell debris developed from blebs derived from polypoid cytoplasmic protrusions of smooth muscle cells of both arteries and veins. They underwent hydropic change and became detached and fragmented particularly after 20 weeks' gestation. Similar hydropic degeneration occurred in endothelial cells of arteries and veins, such changes being consistent with the destructive pattern of hemodynamic stresses.

Development of Human Umbilical Vessels in The Second Trimester of Pregnancy: Histological, Immunohistochemical and Morphometric Study

“…Endothelial injury and damage was most observed at the 16 th gestational week. Stehbens et al [10] in their histological study of human UVs observed cell debris in the walls of umbilical vessels that could be attributed to hemodynamic stress of the fetoplacental circulation resembling early events of atherogenesis. Lu and Kassab, [15] stated that the vascular walls are subjected to three hemodynamic forces; the blood pressure created by cardiac contraction, the circumferential stretch of the vessel with the cardiac cycle, and the shear stress.…”

“…Vascular SMCs the main stromal cells of vascular wall assume structural and physiological functions. It synthesizes the extracellular matrix during development and provide arterial wall with the capacity of withstanding high pressure of circulating blood [10,20] . In addition, the vascular SMCs possess fibroblastic function producing collagen and elastin in the developing media hence collagen content in the vessel wall is a reflection of SMC maturity [8] .…”

“…There was abundant ground substance between SMCs (Figs. 10,11,13). Immunohistochemistry with α-smooth muscle actin demonstrated moderate degree of immune reactivity at the inner layers of SMCs of media in contrast to strong reaction at the outer muscle layers.…”

“…Though, many publications to date described the structure of human umbilical vessels at term [5][6][7][8][9] , few of them compared the structure of these vessels during gestation [10,11] .…”

The Effect of Wharton's Jelly Mesenchymal Stem Cells on a Squamous Cell Carcinoma Cell Line

“…It is typically composed of two arteries and a vein suspended in a hydrated extracellular matrix known as Wharton's jelly. Two veins are originally present, but the second one usually atrophies during pregnancy [9]. Wharton's jelly mesenchymal stem cells (WJMSCs) are more primitive than those isolated from other tissue sources and do not express the major histocompatibility complex (MHC) class II (HLA-DR) antigens [10].…”