Biomedical Engineering Reference
In-Depth Information
Fig. 10.1
Schematic overview of the framework. Mechanical loading of the artery is performed
experimentally with a custom made clamp (
top left image
), and simulated with finite elements
(
bottom left
). After mechanical loading, the damage to the tissue is assessed experimentally in a
custom made functional testing device capable of recording isometric contraction (
top right image
).
This isometric contraction experiment is also simulated with finite elements (
bottom right image
).
Now, the simulation can be repeated for different loading situations, thereby predicting the amount
of damage that will be induced
Another way to assess biological function is to study the condition of the tissue
through morphological imaging. The spatial resolution of the imaging method de-
termines how location-specific the damage can be assessed. Damage to certain con-
stituents or processes can be imaged by applying specific stainings and visualizing
through the corresponding microscopic techniques. For example, in immunofluo-
rescence microscopy, specific antibodies can be labeled with a fluorophore, to visu-
alize endothelial morphology (e.g., with CD31), the smooth muscle cells (e.g., with
alpha-smooth muscle actin), elastin (e.g., with anti-elastin) and collagen (e.g., with
anti-collagen IV). Cell-proliferation and cell-death can also be visualized through
immunofluorescence microscopy, for example, with a TUNEL assay, or with a com-
bined PI (propidium iodide) and syto 13 staining. Propidium iodide (PI) stains all
cell nuclei red, whereas syto 13 stains only intact nuclei green. The combination of
these two stainings therefore yields a 'live-dead'-staining, after which image pro-
cessing can reveal the percentage of cell death in different regions (Megens et al.,
2007
,
2008
).
