Three-dimensional organization of fenestrae labyrinths in liver sinusoidal endothelial cells
Article first published online: 25 JUL 2008
© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd
Volume 29, Issue 4, pages 603–613, April 2009
How to Cite
Braet, F., Riches, J., Geerts, W., Jahn, K. A., Wisse, E. and Frederik, P. (2009), Three-dimensional organization of fenestrae labyrinths in liver sinusoidal endothelial cells. Liver International, 29: 603–613. doi: 10.1111/j.1478-3231.2008.01836.x
- Issue published online: 10 MAR 2009
- Article first published online: 25 JUL 2008
- Received 23 May 2008Accepted 6 June 2008
- atomic force microscopy;
- electron tomography;
- fenestrae labyrinth;
- hepatic endothelium;
- liver sieve;
- liver sinusoidal endothelium;
- TEM sections;
- transendothelial transport
Background/Aims: Liver sinusoidal endothelial cell (LSEC) fenestrae are membrane-bound pores that are grouped in sieve plates and act as a bidirectional guardian in regulating transendothelial liver transport. The high permeability of the endothelial lining is explained by the presence of fenestrae and by various membrane-bound transport vesicles. The question as to whether fenestrae relate to other transport compartments remains unclear and has been debated since their discovery almost 40 years ago.
Methods: In this study, novel insights concerning the three-dimensional (3D) organization of the fenestrated cytoplasm were built on transmission electron tomographical observations on isolated and cultured whole-mount LSECs. Classical transmission electron microscopy and atomic force microscopy imaging was performed to accumulate cross-correlative structural evidence.
Results and Conclusions: The data presented here indicate that different arrangements of fenestrae have to be considered: i.e. open fenestrae that lack any structural obstruction mainly located in the thin peripheral cytoplasm and complexes of multifolded fenestrae organized as labyrinth-like structures that are found in the proximity of the perinuclear area. Fenestrae in labyrinths constitute about one-third of the total LSEC porosity. The 3D reconstructions also revealed that coated pits and small membrane-bound vesicles are exclusively interspersed in the non-fenestrated cytoplasmic arms.