Biomedical Engineering Reference
In-Depth Information
Definition
ICAM-1 - Intracellular Adhesion Molecule 1 (CD54) facilitates adhesion between
leukocytes to endothelial cells during immune and inl ammatory responses.
CAMs IN DCS
We characterized early blood and tissue markers predictive of DCS during the 24 hr
period immediately following compression-decompression of female Sprague-
Dawley rats (Bigley
et al.
2008). Control animals were maintained at 1 atmospheres
absolute pressure ATA (101 kPascal). In animals exposed to 2 (202 kPascal), 3 (303
kPascal), or 4 (404 kPascal) ATA, followed by rapid decompression, increased levels
of TNF-α and interferon gamma (IFN-γ) were found in the circulation at 6 hr at er
decompression, while increased levels of only IL-6 were observed at both 6 and 24
hr following decompression. Signii cant increases in expression of E-selectin and
L-selectin as well as ICAM-1 were observed immunohistochemically in the lungs
and brains of the rats 6 hr at er decompression. h ese levels dropped by 24 hr.
Greater increases in expression of E-selectin and L-selectin around vessels and
connective tissue were seen at 24 hr at er decompression in the quadriceps of rats
exposed to either 3 or 4 ATA. In cardiovascular disorders and reperfusion damage,
the multistep vascular extravasation process is mediated by P-selectin, E-selectin,
L-selectin, ICAM-1 and VCAM-1 (Haverslag
et al.
2008).
Macrophages were seen in high abundance in lung sections of experimental
rats (Bigley
et al.
2008), suggesting that the endothelial vasculature was activated
by leukocytes and that both the macrophages and activated endothelium were
sources of TNF-α and IL-6. IFN-γ-inducible proteins, IP-10 and ICAM-1, were
elevated in the lungs and brains of all experimental rats at both 6 and 24 hr at er
rapid decompression, with higher expression seen at the earlier observation time.
IP-10 was expressed only in the lungs of rats by 24 hr at er decompression, with the
4 ATA rats showing the most marked expression. ICAM-1 and E-selectin, markers
of endothelial activation, were observed in microvessels from the cerebral cortex
within 24 hr at er exposure of male Wistar rats to hypobaric hypoxia (Dore-Duf y
et al.
1999). Increased expression of integrin αv, which activates latent transforming
growth factor-β
(TGF-β) on epithelium in lungs, was found only in the brains of
rapidly decompressed rats (Bigley
et al.
2008).
Notable expression of ICAM-1 was seen only in muscle from rats 24 hr following
rapid decompression at er exposure to 3 or 4 ATA. h is observation implied
that the muscle response to the inl ammatory stimuli requires a period of time
longer than 6 hr. Muscle cells present antigens, produce cytokines, and upregulate
expression of ICAM-1 (Nagaraju 2001), suggesting that the inl ammatory
response could be modulated locally or by immune cells directed to this site. DCS
can simultaneously af ect endothelium at multiple areas, such as the brain, lung,
