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Liver Sinusoidal Endothelial Fenestrations in Caveolin-1 Knockout Mice

2010; Wiley; Volume: 17; Issue: 1 Linguagem: Inglês

10.1111/j.1549-8719.2009.00004.x

1549-8719

Alessandra Warren, Victoria C. Cogger, Irwin M. Arias, Robert S. McCuskey, David G. Le Couteur,

Lipid metabolism and disorders

Microcirculation (2010) 17, 32–38. doi: 10.1111/j.1549-8719.2009.00004.x Objective: Fenestrations are pores in the liver sinusoidal endothelium that facilitate the transfer of particulate substrates between the sinusoidal lumen and hepatocytes. Fenestrations express caveolin-1 and have structural similarities to caveolae, therefore might be a form of caveolae and caveolin-1 may be integral to fenestration structure and function. Therefore, fenestrations were studied in the livers of caveolin-1 knockout mice. Methods: Scanning, transmission and immunogold electron microscopic techniques were used to study the liver sinusoidal endothelium and other tissues in caveolin-1 knockout and wild-type mice. Results: Comparison of fenestrations in wild-type and knockout mice did not reveal any differences on either scanning or transmission electron microscopy. The diameter of the fenestrations was not significantly different (74 ± 13 nm knockout mice vs 78 ± 12 nm wild-type mice) nor was the fenestration porosity (6.5 ± 2.1 knockout vs 7.3 ± 2.4% wild-type mice). In contrast, adipocytes and blood vessels in other tissues lacked caveolae in the knockout mice. Caveolin-1 immunogold of livers of wild-type mice indicated sparse expression in sinusoidal endothelial cells. Conclusions: The normal structure of fenestrations in the liver sinusoidal endothelium is not dependent upon caveolin-1 and fenestrations are not a form of caveolae.