Myoedothelial connection, a relationship between spiral arrangement of smooth muscle cells and endothelium in resistance muscular arteries

Abstract

AbstractBackground and Purpose: Conventionally, the architecture of the artery wall is based upon the close-packed smooth muscle cells, endothelial and adventitial cells in both sides of internal elastic lamina (IEL). However, the adventitia and endothelium are now viewed as key players in vascular growth and repair. Recent work raises fundamental questions about the cellular heterogeneity of arteries, time course, triggering of normal and pathological re-modeling.Materials and Methods: Twelve wild type mice were employed. After killing with CO2 inhalation, dissected mesenteric arteries were removed and cleaned with adipose tissue. Arteries were mounted in the perfusion pressure myograph under normal pressure (70mmHg) in Kreb’s solution, which bubbled with 95% O2 and 5% CO2 to pH 7.4, at 37°C. After staining with fluorescent ligands (Syto 13) for nuclei and (DIO 1µM) for cytoplasm, arteries were scanned with the Laser Scanning Co focal Microscopy (LSCM) under (488nm/515nm), (484nm/501nm) and (543nm/580nm) Argon-Helium ion laser wavelength.Results: Three dimensional images of computer observation suggest that there may be a close relationship between the helical organization of smooth muscle cells and the underlying pattern of endothelial cells (myoendothelial connection).Conclusion: Tight junctions between cells must be broken and remade during the remodeling process. This suggests a carefully controlled defensive structure for intra-cellular connections, that is capable of withstanding the acute stresses of normal function, but which must be capable of modification to adapt to a new state, when the bio-physical conditions dictate. Endothelial mosaicism related to spiral arrangements of underlying smooth muscle cells, are associated with the functional cell connections. Taken together, these issues provide an exciting new phase in understanding the physiological modeling of the vascular wall, producing a new view of the dynamic nature of vascular structure.Key words: Myoedothelial Connections, Remodeling, Mesenteric Arteries, Internal Elastic Lamina, Fluorescent StainingJ Mazand Univ Med Sci 2008; 18(64): 60-70 (Persian