Alveolar epithelial type II

The human alveolar epithelium consists of two cell types type I (alveolar epithelial type I [ATI], pneumocyte I) and type n (alveolar epithelial type II... 

Fehrenbach H (2001) Alveolar epithelial type II cell defender of the alveolus revisited. Respir Res 2(1 ) 33—46... 

Mixtures of NiCl2 and C0CI2 induced a synergistic (that is, greater than additive) toxic response in cultures of immortahsed f tal rat alveolar epithelial type II cells (Cross et al. 2001). 

Me- C]Choline incorporation into phosphatidylcholines was decreased in isolated rat alveolar epithelial type II cells exposed to paraquat (5-10 ) and hyperoxia (90 % O2) (Haagsman et al. 1987). The incorporation of [1- C]acetate into phosphatidylcholines, phosphatidylglycerols and neutral lipids appeared to be very sensitive to inactivation by paraquat. The rate of [l- C]palmitate incorpora-... 

Chen Z, Jin N, Narasaraju T, Chen J, McFarland LR, Scott M, Liu L (2004) Identification of two novel markers for alveolar epithelial type I and II cells. Biochem Biophys Res Commun 319(3) 774—780... 

Chen J, Chen Z, Narasaraju T, Jin N, Liu L (2004) Isolation of highly pure alveolar epithelial type I and type II cells from rat lungs. Lab Invest 84(6) 727-735 Erratum in Lab Invest 85(9) 1181 (2005)... 

Despite the fact that most of the alveolar surface is composited of alveolar epithelium, three primary types of cells are present in the alveoli type I alveolar cells, type II alveolar cells, and alveolar macrophages. Type I alveolar cells are also referred to as squamous pulmonary epithelial cells and are the continuous lining of the alveolar sac. Type II alveolar cells are also referred to as septal cells. Type II alveolar cells secrete the alveolar fluid that is necessary to keep the surface moist and to maintain surface tension of the alveolar fluid surface tension is necessary to keep the alveoli from collapsing. Alveolar fluid is a suitable environment for proteins when compared to the low pH and high protease levels associated with the intestine... 

Collectins Alveolar type II cells and non-ciliated bronchiolar epithelial cells Bacterial and fungal cell walls and viruses Enhance phagocytosis of macrophages and neutrophils activating cells Cigarette smoke decreases the production of collectin [48] ozone decreases function [49]... 

Lieber M, Smith B, Szakal A, Nelson-Rees W, Todaro G (1976) A continuous tumor-cell line from a human lung carcinoma with properties of type II alveolar epithelial cells. Int J Cancer 17(1 ) 62—70... 

Stephens et al have shown that, in rats, the degenerative changes in Type I alveolar cells occur after exposure to ozone at concentrations as low as 0.2 ppm for 3 h and that cells are replaced by Type II alveolar cells beginning a day after the exposure. With electron microscopy, Bils noted that the swelling of the epithelial alveolar lining cells of mice occurred after exposure to ozone at 0.6-1.3 ppm for 4 h. These changes... 

The lung possesses a variety of epithelial cells, with different types found in different regions. Alveolar type II cells represent a potentially important target for the delivery of intracellular enzymes, such as superoxide dismutase (SOD) and catalase, which do not reach their full complement until the final 10-15% of gestation. Until the enzymes do reach their full complement, the premature baby... 

At the distal respiratory site, the alveolar epithelial cell layer is much flatter (0.1 -0.5 pm) and composed of two major cell types, squamous type I and agranular type II pneumocytes. Type I pneumocytes are non-phagocytic and highly flattened cells with broad and thin extensions. They occupy -95 % of the alveolar luminal surface, although they are less numerous than type II cells. The remaining surface is occupied by type II pneumocytes, which have blunt microvilli and contain multivesicular bodies [3, 11]. 

The lung comprises about 40 different cell types, amongst which type I and type II alveolar epithelial cells are the major types targeted by pulmonary drug delivery systems. Type I cells play an important role in the absorption process of proteins, while type II cells produce surfactant, regulate the immune response, and serve... 

J. Wilkes, J.H. Dark,T.D. Tetley, and J.A. Kirby. 1994. Constitutive expression of MHC and adhesion molecules by alveolar epithelial cells (type II pneumo-cytes) isolated from human lung and comparison with immunocytochemical findings./. Cell Sci. 107 (Pt 2) 443-449. 

The rate of liposome accumulation in alveolar type-II cells is dependent on lipid composition. It is therefore possible to select liposome compositions displaying minimal interaction with these cells and thereby function as controlled-release systems for entrapped solutes. For example, liposomes composed of dipalmitoylphosphatidylcholine and cholesterol and containing entrapped sodium cromoglycate will provide sustained delivery of the drag for over 24 hours. Conversely other liposome compositions could be utilized for enhanced epithelial interaction and transport of the drug (e g. cationic lipids for the cellular delivery of the CFTR gene). 

Castleman, W. L., Northrop, P. J., and McAllister, P. K. (1989) Replication of parainfluenza (Sendai) virus in isolated rat pulmonary type II alveolar epithelial cells. Am. J. Pathol. 134,1135-1142. 

Huang X, Wu J, Zhu W, Pytela R, Sheppard D. Expression of the human integrin beta6 subunit in alveolar type II cells and bronchiolar epithelial cells reverses lung inflammation in beta6 knockout mice. Am J Respir Cell Mol Biol 1998 19(4) 636 12. 

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