Monocyte adhesion to balloon-injured arteries: the influence of endothelial cell seeding.
OBJECTIVE
Deendothelialization of injuries of the artery disrupts normal vascular homeostasis, affecting both the structural integrity of the blood vessel wall, as well as the interaction of the arterial surface with blood components such as platelets, leukocytes, and circulating proteins. Leukocyte and, in particular, monocyte recruitment to damaged vessels has been implicated in the pathogenesis of intimal hyperplasia. We hypothesize that reendothelialization is an important modulator of monocyte adhesion to healing arterial surfaces.


METHODS
New Zealand white rabbits (n = 20) were subjected to bilateral iliofemoral artery balloon injury. Cultured, autologous venous endothelial cells (ECs) were immediately seeded onto one vessel, whereas the contralateral artery received medium alone, to accelerate endothelial relining. Vessels were harvested (5-9 days after injury) for analysis of permeability (Evans Blue dye exclusion), endothelial coverage (anti-CD31 immunohistochemistry), monocyte adhesion (ex vivo binding of 51Na2CrO4-labeled monocytic THP-1 cells), and monocyte recruitment (RAM-11 immunohistochemistry).


RESULTS
Improved EC coverage was evidenced by positive staining for CD31 in the seeded vessels. Vessel wall permeability was markedly reduced in EC-seeded arteries (29% +/- 10% vs 99% +/- 0% surface Evans blue staining, P <.005), consistent with restoration of a functional endothelial barrier. EC seeding significantly reduced ex vivo THP-1 binding to vessels explanted at a mean of 8 days after injury (45,170 +/- 8939 vs 85,994 +/- 16,500 cells/cm2, P <.05). However, RAM-11 staining revealed no significant difference in overall macrophage accumulation between seeded and control vessels 1 week after injury (111 +/- 22 vs 95 +/- 14 cells/section, P =.36).


CONCLUSIONS
Immediate seeding of a balloon-injured rabbit artery with cultured ECs results in accelerated restoration of the endothelial lining. At 1 week, barrier function is improved, and the seeded vessel surface is less adhesive to activated monocytes ex vivo, as compared with injured controls. Nonetheless, EC-seeded and nonseeded arteries demonstrate similar total macrophage accumulation over 1 week. These data suggest that after mechanical arterial injury, endothelial coverage may be one important variable influencing leukocyte adhesion.
Gangadharan
S P
SP
Division of Vascular Surgery, Brigham and Women's Hospital, and the Harvard Institutes of Medicine, Harvard Medical School, Boston, Mass 02115, USA.
Eslami
M H
MH
Weiss
I P
IP
Sui
X
X
Conte
M S
MS
D000800:Angioplasty, Balloon / Q000009:adverse effects; D000818:Animals; D002448:Cell Adhesion; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D007083:Iliac Artery / Q000293:injuries* / Q000473:pathology*; D007150:Immunohistochemistry; D008297:Male; D008856:Microscopy, Fluorescence; D009000:Monocytes / Q000473:pathology* / Q000502:physiology; D011817:Rabbits; D012680:Sensitivity and Specificity