Author + information
- Received April 3, 1997
- Revision received August 7, 1997
- Accepted August 21, 1997
- Published online December 1, 1997.
- Jan Nilsson, MD, PhDA,
- Federico Calara, MAA,
- Jan Regnstrom, MD, PhDA,
- Anna Hultgardh-Nilsson, PhDB,
- Sean Ameli, MDC,
- Bojan Cercek, MD, PhD, FACCC and
- Prediman K Shah, MD, FACCC,* ()
- ↵*Dr. Prediman K. Shah, Cedars-Sinai Medical Center, Room 5347, 8700 Beverly Boulevard, Los Angeles, California 90048.
Objectives. In this study we tested the hypothesis that immunization with homologous oxidized low density lipoprotein (oxLDL) would inhibit the neointimal response to balloon injury in hypercholesterolemic rabbits.
Background. Immunization with homologous oxLDL has been shown to markedly reduce aortic atherosclerosis in LDL receptor-deficient as well as cholesterol-fed rabbits; however, the effect of this strategy on the balloon injury-induced neointimal lesion is unknown.
Methods. New Zealand White rabbits were immunized with 280 μg of homologous native LDL (n = 5), copper-oxidized LDL (n = 5) or phosphate buffer as control (n = 5) and fed a 1% cholesterol diet. Rabbits were reimmunized after 3 weeks, and balloon injury of the right ileofemoral artery was performed 1 week later. Four weeks after balloon injury, rabbits were killed, and the neointimal lesion area was measured by computerized morphometry after perfusion fixation of the arteries. Circulating antibodies against oxLDL were measured by enzyme-linked immunosorbent assay.
Results. In comparison with the control animals, those immunized with oxLDL had a 58% reduction in the neointimal area (0.53 ± 0.13 vs. 1.27 ± 0.26 mm2; p = 0.01). The group immunized with native LDL had a 19% reduction in the neointimal area compared with the control group (p = NS). Circulating cholesterol levels and antibody titers against oxLDL were comparable in the three groups. There was a trend toward reduced immunoreactivity for T cells and oxLDL in the neointima of oxLDL-immunized animals.
Conclusions. Hypercholesterolemic rabbits immunized with homologous oxLDL have a markedly reduced neointimal area after balloon injury despite severe hypercholesterolemia. Together with previous work, these data suggest that an immunization strategy (vaccination) against atherosclerosis and restenosis warrants further investigation.
☆ This study was supported by grants from the American Heart Association, Dallas, Texas; the Swedish Medical Research Council (8311), the Swedish Heart and Lung Foundation, the Tore Nilssons Fund, the Swedish Society of Medicine and King Gustav V’s 80th Birthday Fund, Stockholm, and the Grand Foundation of Los Angeles and the United Hostesses of Los Angeles.
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- Received April 3, 1997.
- Revision received August 7, 1997.
- Accepted August 21, 1997.
- The American College of Cardiology