Biomedical Engineering Reference
In-Depth Information
function and reduces inl ammatory markers in hypertensive patients with type 2
diabetes (Martina
et al.
2008).
Smoking
Cigarette smoking is a major risk factor for the development of atherosclerosis.
Cigarette smoke is associated with abnormal endothelial function in both active
and passive young adult smokers. A study performed by Adams
et al.
(1997)
assessed the ef ects of cigarette smoking on adhesion of human monocytes to
HUVECs and measured the ef ects of Arg supplementation on this interaction.
h ey collected serum from eight smokers with no other coronary risk factors and
eight age- and gender-matched non-smokers. Serum was added to HUVECs and
incubated for 24 hr. Human monocytes were then added to HUVECs for 1 hr,
and adhesion was analyzed by microscopy. To assess the reversibility, monocyte/
endothelial cell adhesion was measured for 2 hr at er 7 g of Arg was orally
administered. h e results showed that monocyte/endothelial adhesion and EC
expression of ICAM-1 increased in smokers compared to control subjects. At er
oral Arg administration, monocyte/endothelial adhesion was reduced in smokers,
as was EC expression of ICAM-1. h ese results indicated that cigarette smoking is
associated with increased monocyte-EC adhesion, and this abnormality is acutely
reversible by oral Arg supplementation.
Surgery and Sepsis
Surgery and infection result in inl ammatory reactions and stimulate the
production of a variety of endogenous mediators. h ese mediators initiate
immune responses and metabolic alterations that are integral to a response by
a host to injury. h e activation of leukocytes and ECs and the expressions of
adhesion molecules are important events in the pathogenesis of the inl ammatory
response. A previous study performed by our laboratory investigated the ef ects
of dif erent Arg levels on adhesion molecule expression by ECs and leukocytes,
and the transendothelial migration of polymorphonuclear neutrophils (PMNs)
through ECs stimulated by biological l uid from surgical patients was examined.
We treated ECs and PMNs with dif erent Arg concentrations, including low (50
μM), approximately physiological (100 μM), and high (1000 μM) Arg levels in an
in vitro
study stimulated with patient's peritoneal drain l uid. h e results showed
that ECs and PMNs were activated at er peritoneal drain l uid stimulation. A low
Arg concentration comparable to a catabolic condition resulted in higher ICAM-1
and VCAM-1 expressions by ECs. Also, the IL-8 receptor and CD11a/CD18
expressed by neutrophils were enhanced. Arg administration at levels similar to or
higher than physiological concentrations reduced IL-8 and CAM expressions, and
decreased PMN transmigration at er stimulation by peritoneal drain l uid from
