Electron Microscopy in Angiogenesis Research
Electron microscopy is a powerful tool for detection and supervision of all key cell differentiation processes of in vivo neovascularisation that are also considered important in realistic in vitro models of angiogenesis, vasculogenesis and vascular remodelling. It allows detection and supervision of all major vascular differentiation processes for both, in vivo and in vitro models of neovascularisation, but preparation of samples requires experience and particular diligence in order to preserve the damageable spatial structures. The wealth of available information provided by scanning and transmission electron microscopy approaches may be useful for subsequent, e.g., biochemical or molecular, studies and thus delivers important controls for further experimental designs. In order to preserve the fragile three-dimensional cellular structures for EM, particularly of in vitro models, modified processing techniques for both TEM and SEM need to be applied that are emphasised in this chapter. E.g., different pre-embedding and sample taking techniques are provided and illustrated with hands-on photographs from the electron microscopy laboratory. Scanning electron microscopy of vascular microcorrosion casts – particularly important for studying intussusceptive processes and assessing tumour neovascularisation – is also described.
KeywordsOsmium Tetroxide Culture Vessel Scan Electron Microscopy Examination Casting Medium Colloidal Carbon
The authors particularly wish to thank our experienced EM laboratory staff Monika Sachtleben and Verena Holle (née Eckert-Funke), for their ever-lasting enthusiasm and expert support. Many of our findings and experiences from processing cell culture models of angiogenesis for EM were previously published in the article “Electron microscopy of cultured angiogenic endothelial cells”  and are used with permission. The presented agar-pre-embedding technique allowing optimal sample retrieval for processing three-dimensional in vitro-angiogenesis models, in particular, is primarily the result of Monika Sachtleben’s “penchant for perfectionism” within her EM laboratory.
Our graphic designer team also supported this chapter: Martin Werner assisted us with the hands-on photos from the EM laboratory, and Diemut Starke supplied the excellent schematic drawing illustrating the trouble-shooting process in sputter-coating for SEM.
Our colleagues and former doctorate students Dr. Mahtab Bahramsoltani (Institute of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Leipzig), Dr. Sabine Kaessmeyer (Institute of Veterinary Anatomy, Faculty of Veterinary Medicine, Freie Universität Berlin), Dr. Jasmin Lienau (Centre for Musculoskeletal Surgery, Charité, Berlin), Dr. Pawel Janczyk (Federal Institute for Risk Assessment, Unit Molecular Diagnostics and Genetics, Department of Biological Safety, Berlin) and Dr. Sophie Backhaus (née Hansen) generously supported this chapter with brilliant EM micrographs.
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