Article
Morphochemical analyses of the aneurysm wall – label-free multiphoton microscopy as a tool to investigate intracranial aneurysms
Morphochemische Analysen der Aneurysmawand – Markierungsfreie Multiphotonenmikroskopie als Werkzeug zur Untersuchung von Veränderungen intrakranieller Aneurysmen
Search Medline for
Authors
-
Tina Sehm
- Universitätsklinikum Dresden, Klinik und Poliklinik für Neurochirurgie, Dresden, Deutschland
-
Ortrud Uckermann
- Universitätsklinikum Dresden, Klinik und Poliklinik für Neurochirurgie, Dresden, Deutschland
-
Roberta Galli
- Universitätsklinikum Dresden, Klinik für Anästhesiologie und Intensivtherapie, Klinisches Sensoring und Monitoring, Dresden, Deutschland
-
Elke Leipnitz
- Universitätsklinikum Dresden, Klinik und Poliklinik für Neurochirurgie, Dresden, Deutschland
-
Dietmar Krex
- Universitätsklinikum Dresden, Klinik und Poliklinik für Neurochirurgie, Dresden, Deutschland
-
Gabriele Schackert
- Universitätsklinikum Dresden, Klinik und Poliklinik für Neurochirurgie, Dresden, Deutschland; Nationales Zentrum für Tumorerkrankungen (NCT), Standort Dresden, Heidelberg, Deutschland
-
Matthias Kirsch
- Universitätsklinikum Dresden, Klinik und Poliklinik für Neurochirurgie, Dresden, Deutschland; CRTD/DFG-Center for Regenerative Therapies Dresden – Cluster of Excellence TU Dresden, Dresden, Deutschland; Nationales Zentrum für Tumorerkrankungen (NCT), Standort Dresden, Heidelberg, Deutschland
| Published: | May 8, 2019 |
|---|
Outline
Text
Objective: Label-free multiphoton microscopy was applied to elicit changes in the arterial wall of human intracranial cerebral aneurysms. This technique is able to detect structures and cells often not addressed by conventional histological staining methods.
Methods: Label-free multiphoton microscopy was performed on cryosections of resected aneurysm domes of human patients and integrated three modalities: coherent anti-Stokes Raman scattering (CARS), endogenous two-photon fluorescence (TPEF) and second harmonic generation (SHG). The distribution of lipids was displayed by CARS, the structural organization of collagen was shown by SHG and TPEF identified phagocytic microglia/macrophages as well as elastin fibers. Raman spectroscopy was used for reference in order to identify certain molecular species.
Results: Ruptured (n=5; diameter 5–20 mm) and unruptured (n=5; diameter 9–16 mm) intracranial cerebral aneurysms were investigated. Amongst others, a healthy arterial wall was characterized by an intact endothelium and linearly organized smooth muscle cells. The wall of aneurysms displayed a high degree of structural alterations. Additionally, ruptured aneurysms displayed significant wall degeneration. Unruptured aneurysms were characterized by thickened wall with disorganised (myointimal hyperplasia) and decellularized smooth muscle cells. Raman spectroscopy confirmed vascular calcifications (calcium hydroxyapatite 960 cm-1, calcium carbonate apatite 1073 cm-1) and thrombus formation (heme groups-hemoglobin: 752, 967, 1122, 1248, 1563 and 1579 cm-1). Most of the aneurysms displayed fragmentation or a complete loss of the internal elastic membrane. Plaque formation was confirmed in ruptured aneurysm. Lipid deposits were observed by label-free multiphoton imaging and further analyzed by Raman spectroscopy. Raman bands at 429, 752, 1087, 1130, 1299, 1301, 1442, 1464 and 1739 cm-1 indicate the presence of cholesterol and cholesterol esters. Ruptured aneurysms had extremely thin and decellularized areas within the smooth muscle cells and displayed hypercellular areas as well.
Conclusion: Both methods, label-free multiphoton imaging and Raman spectroscopy, are well suited to provide morphological and biochemical information which are crucial for understanding the changes in the arterial wall of intracranial aneurysms. In the future, this may help to improve the understanding of mechanisms of plaque development and area of rupture prediction.
