“
“Please cite this paper as: Wagner R, Modla S, Hossler F, Czymmek K. Three-dimensional analysis and computer modeling of the capillary endothelial vesicular system with electron tomography. Microcirculation 19: 477–484, 2012. Objective:  We examined the three-dimensional organization of the endothelial vesicular system with TEM tomography of semi-thick sections. Materials and methods:  Mouse abdominal muscle capillaries were perfused with terbium to

label vesicular compartments open to the luminal surface. The tissue was prepared for TEM and semi-thick (250 nm) sections were cut. Dual axis tilt series, collected from +60° to −60° at 1° increments, were acquired BMS-354825 research buy in regions of labeled abluminal caveolae. These tomograms were reconstructed and analyzed to reveal three-dimensional vesicular

associations not evident in thin sections. Results:  Reconstructed tomograms revealed free vesicles, both labeled and unlabeled, in the endothelial INK 128 solubility dmso cytoplasm as well as transendothelial channels that spanned the luminal and abluminal membranes. A large membranous compartment connecting the luminal and abluminal surfaces was also present. Computer modeling of tomographic data and video animations provided three-dimensional perspectives to these structures. Conclusions:  Uncertainties associated with other three-dimensional methods to study the capillary wall Rebamipide are remedied by tomographic analysis of semi-thick sections. Transendothelial channels of fused vesicles and free cytoplasmic vesicles give credence to their role as large pores in the transport of solutes across the walls of continuous capillaries. Membranous vesicular compartments are the most conspicuous features in the cytoplasm of capillary endothelial cells. Although there is substantial evidence that they are

involved in transendothelial transport, the mechanism(s) of this transport and its structural correlates are unclear. Ultrastructural analysis of the capillary endothelial system has been impaired by the lack of three-dimensionality of conventional TEM sections. Stereoviewing of tilted thick sections with high-voltage EM [26] is limited to a single viewing angle and structures are often obscured by the overlapping of details in two-dimensional images recorded from thicker sections. Reconstruction of serial ultrathin sections [1,4,5] requires difficult to obtain ribbons of ultrathin sections and are constrained to small sampled regions. Moreover, serial sections are limited in the z-resolution to twice the section thickness, making nanometer-sized details difficult to resolve.