Elevation of plasma high-density lipoprotein concentration reduces interleukin-1-induced expression of E-selectin in an in vivo model of acute inflammation.
BACKGROUND
Although there is strong evidence that plasma HDL levels correlate inversely with the incidence of coronary artery disease, the precise mechanism(s) for the protective effect of HDLs remains unclear. We recently showed that HDLs inhibit endothelial cell expression of cytokine-induced leukocyte adhesion molecules in vitro. Our study therefore sought to test the hypothesis that elevating the level of circulating HDLs would inhibit endothelial cell activation in vivo.


RESULTS
We used a porcine model of inflammation previously established in our laboratory, in which the level of vascular endothelial cell expression of E-selectin in interleukin (IL)-1alpha-induced skin lesions was measured by the uptake of a radiolabeled anti-E-selectin antibody (1.2B6). Porcine plasma HDL levels were elevated by use of a bolus injection of reconstituted discoidal HDL (recHDL). These particles resemble nascent HDL particles in shape and contain apolipoprotein A-I as the sole protein and soybean phosphatidylcholine as the sole phospholipid. We found that recHDLs inhibited the expression of IL-1alpha-induced E-selectin by porcine aortic endothelial cells in vitro, confirming that the inhibitory effect is conserved with synthetic HDLs and demonstrating that the phenomenon is not restricted to human endothelial cells. In vivo, elevating the circulating level of HDLs approximately 2-fold led to significant inhibition of basal and IL-1alpha-induced E-selectin expression by porcine microvascular endothelial cells.


CONCLUSIONS
These observations demonstrate the potential anti-inflammatory action of HDLs and provide support for the further investigation of the mechanisms underlying the inhibitory effects of HDLs on endothelial cell activation.
Cockerill
G W
GW
British Heart Foundation Cardiovascular Research Unit, National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital Campus, London, UK. g.w.cockerill@mds.qmw.ac.uk
Huehns
T Y
TY
Weerasinghe
A
A
Stocker
C
C
Lerch
P G
PG
Miller
N E
NE
Haskard
D O
DO
D000208:Acute Disease; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001011:Aorta; D016632:Apolipoprotein A-I / Q000097:blood / Q000494:pharmacology; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004337:Drug Carriers; D019040:E-Selectin / Q000096:biosynthesis*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D005434:Flow Cytometry; D007249:Inflammation / Q000378:metabolism* / Q000473:pathology; D007375:Interleukin-1 / Q000378:metabolism* / Q000494:pharmacology; D008075:Lipoproteins, HDL / Q000097:blood* / Q000493:pharmacokinetics / Q000494:pharmacology; D009928:Organ Specificity; D011994:Recombinant Proteins / Q000097:blood / Q000493:pharmacokinetics / Q000494:pharmacology; D012867:Skin / Q000098:blood supply / Q000473:pathology; D013552:Swine
D000911:Antibodies, Monoclonal; D016632:Apolipoprotein A-I; D004337:Drug Carriers; D019040:E-Selectin; D007375:Interleukin-1; D008075:Lipoproteins, HDL; D011994:Recombinant Proteins