Endothelial cell barrier

The passage of molecules across epithelial and endothelial cell barriers occurs by either of two general pathways paracellularly (between the cells) or transcellu-larly (through the cells) (Fig. 1). Paracellular flux occurs strictly by passive diffu-... 

The endothelial cell barrier normally restricts the passage of formed elements (e.g., red cells) through the glomerular capillary wall, but it presents no restriction to the passage of different macromolecules. 

In order to cross the endothelial cell barrier, the macromolecules or drug-targeting complex must leave the circulation by either intercellular junctions or a mechanism similar to tnmscytosis. The permeability of the vessel wall could be... 

To reach the perivascular interstitium, immunoglobulins and other molecules must breach the endothelial cell barrier. Simionescu and Anthohe [17] note that an adult human contains more than 1013 endothelial cells which cover 7000 square meters and mass approximately 1kg.3 Egress to interstitium is affected by type of endothelium (continuous, fenestrated, or sinusoidal), endothelial uptake and transport processes (receptor-dependent or receptor-independent uptake, endocytosis and transcytosis4), paracellular (between or... 

Enhanced transfection with larger vectors was also seen with lipid-DNA lipoplexes in CHO cells [113]. However, the opposite was found with linear PEI (L-PEI) in vivo. Smaller complexes led to higher levels of gene expression in adult and newborn mice, which correlated to their diffusivity through tissue [100]. In this study, L-PEI DNA complexes were shown to cross the endothelial cell barrier following intravenous administration and preferentially transfect pulmonary cells [92]. Cationic lipids, on the other hand, show some expression in pulmonary cells following intravenous administration but preferentially transfected endothelial cells [51,53,114,115], perhaps due to their reduced stability compared to polyplexes. 

Satchell SC, Anderson KL, Mathieson PW (2004) Angiopoietin 1 and vascular endothelial growth factor modulate human glomerular endothelial cell barrier properties. J Am Soc Nephrol 15(3) 566-574... 

Egress of more mature cells from the bone marrow occurs through the endothelial cell barrier. Release of cells such as neutrophils may be stimulated by complement, steroids, or endotoxin. Immature (progenitor) cells that may ultimately become any one of the blood cellular components can be mobilized from the bone marrow into peripheral blood by the administration of a cytotoxic chemotherapy drug (e.g., cyclophosphamide) or a colony-stimulating factor (G-CSE or GM-CSE). This process is commonly referred to as priming the bone marrow for peripheral blood progenitor or stem cell transplantation (see Chap. 134). 

D. Bottaro, D. Shepro, S. Peterson, and H. B. Hechtmann. Serotonin, norepinephrine and histamine mediation of endothelial cell barrier function in vitro. J. Cell Physiol. 728 189-194(1986). 

Cardiovascular eNOS inhibition - Cardiac contractile dysfunction Reduced endothelial cell barrier... 

The blood-brain barrier (BBB) forms a physiological barrier between the central nervous system and the blood circulation. It consists of glial cells and a special species of endothelial cells, which form tight junctions between each other thereby inhibiting paracellular transport. In addition, the endothelial cells of the BBB express a variety of ABC-transporters to protect the brain tissue against toxic metabolites and xenobiotics. The BBB is permeable to water, glucose, sodium chloride and non-ionised lipid-soluble molecules but large molecules such as peptides as well as many polar substances do not readily permeate the battier. 

The normal arterial wall consists of the intima, media, and adventitia, as illustrated in Fig. 4—3A. The endothelium is located in the intima and consists of a layer of endothelial cells that line the lumen of the artery and form a selective barrier between the vessel wall and blood contents. The internal elastic lamina separates the intima and media, where vascular smooth muscle cells are found. The vascular adventitia comprises the artery s outer layer. Atherosclerotic lesions form in the subendothelial space between the endothelial cells and internal elastic lamina. 

MV Shah, KL Audus, RT Borchardt. The application of bovine brain micro vessel endothelial-cell monolayers grown onto polycarbonate membranes in vitro to estimate the potential permeability of solutes through the blood-brain barrier. Pharm Res 6 624-627, 1989. 

Miller DW, KL Audus, RT Borchardt. (1992). Cultured bovine brain microvessel endothelial cells A model of the blood brain barrier. J Tiss Cult Meth 14 217-224. 

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