Leukocyte-endothelium interaction during the early stages of hypercholesterolemia in the rabbit: role of P-selectin, ICAM-1, and VCAM-1.
The early effects of hypercholesterolemia on leukocyte-endothelium interaction were studied in vivo in the rabbit mesenteric microcirculation. Rabbits fed a 0.5% high-cholesterol (HC) diet showed elevated plasma cholesterol levels during the 1 to 2 weeks of HC feeding (P<0.001 versus control diet-fed rabbits). Intravital microscopy of mesenteric venules revealed that leukocyte rolling had increased 10-fold (P<0.001 versus control-fed group) at the end of the first week of the HC diet, which was sustained after 2 weeks of HC feeding (P<0.001 versus control-fed rabbits). Firm adherence of leukocytes to the endothelium was moderately increased after a 1-week period of hypercholesterolemia (P<0.05) but increased by 12-fold at 2 weeks (P<0.001 versus control diet-fed and P<0.01 versus 1-week HC-fed rabbits). Upregulation of the endothelial cell adhesion molecules P-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 was observed immunohistochemically on the intestinal microvascular endothelium of HC-fed rabbits. P-selectin was maximally expressed within the first week of the HC diet and remained elevated during the second week of cholesterol feeding (P<0.01 versus control). In contrast, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were moderately upregulated at 1 week but were highly expressed after 2 weeks of the HC diet (P<0.05 and P<0.001 versus control, respectively). Basal release of NO from both mesenteric microvascular and aortic endothelium in cholesterol-fed rabbits was progressively reduced after 1 (P<0.05) and 2 (P<0.01) weeks. Our data suggest that enhanced leukocyte-endothelium interaction occurs in vivo in the rabbit microcirculation during the first 2 weeks of hypercholesterolemia. This phenomenon is associated with impaired basal NO release and progressive endothelial surface expression of endothelial cell adhesion molecules (ie, P-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1) in the microvasculature.
Scalia
R
R
Department of Physiology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107-6799, USA.
Appel
J Z
JZ
Lefer
A M
AM
D000818:Animals; D001794:Blood Pressure; D002448:Cell Adhesion; D002791:Cholesterol, Dietary / Q000008:administration & dosage; D004730:Endothelium, Vascular / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006937:Hypercholesterolemia / Q000503:physiopathology*; D007150:Immunohistochemistry; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis / Q000502:physiology*; D007962:Leukocytes / Q000502:physiology*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019007:P-Selectin / Q000032:analysis / Q000502:physiology*; D011817:Rabbits; D019010:Vascular Cell Adhesion Molecule-1 / Q000032:analysis / Q000502:physiology*
D002791:Cholesterol, Dietary; D004791:Enzyme Inhibitors; D019007:P-Selectin; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester