Objective-Caffeic acid phenethyl ester (CAPE), a natural flavonoid, specifically blocks activation of nuclear factor-B (NF-B). We examined the effects of oral CAPE supplementation on atherogenesis in apolipoprotein E-deficient (apoEϪ/Ϫ) mice. Methods and Results-Ten-week-old male apoEϪ/Ϫ mice were supplemented orally with CAPE (30 mg/kg body weight) for 12 weeks. At the end of administration, atherosclerosis progression, NF-B activity, gene expression profiling by microarray analysis, and oxidative stress were studied. Treatment of apoEϪ/Ϫ mice with CAPE significantly reduced aortic atherosclerosis, NF-B activity, and expression of NF-B-related genes in the aorta. Moreover, expression of other gene clusters such as basic transcription factors, growth factors, cytokines, cell adhesion proteins, and extracellular matrix were also significantly reduced by treatment with CAPE. Plasma isoprostane level in apoEϪ/Ϫ mice was also significantly reduced by CAPE.
Conclusion-In
N uclear factor-B (NF-B) is a good therapeutic targetfor cardiovascular disease, 1,2 and numerous efforts are being made to develop safe NF-B inhibitors. Among the candidates are natural flavonoids, which constitute a promising class of dietary antioxidants that are found ubiquitously in fruits, vegetables, and tea. For example, resveratol, which is found in red wine, can inhibit NF-B activity, the abrogation of which may contribute to the ability of red wine to reduce mortality from coronary heart disease and cancer. 3,4 Curcumin, another NF-B inhibitor, is an effective inhibitor of tumor initiation and promotion in different carcinogen-induced models. 5 Among these natural flavonoids, the most promising is caffeic acid phenethyl ester (CAPE), which is structurally related to 3,4-dihydroxycinnamic acid and can be obtained from propolis, a honey constituent. 6 CAPE is the only compound that has been shown to inhibit the HIV integrase enzyme needed for integration of HIV DNA into the host genome 7 and is a potent and specific NF-B inhibitor. 8 We clarified recently that CAPE induced apoptosis in human breast cancer cells, but not in normal cells, by inhibiting NF-B, leading to fas aggregation. 9 The present studies were designed to examine whether CAPE could prevent atherosclerosis by inhibiting NF-B activity in vivo.
Methods
Animals and CompoundAll experimental procedures were in accordance with institutional guidelines for animal research. Apolipoprotein E-deficient (apoEϪ/Ϫ) mice were purchased from Taconic. CAPE was obtained from Bachem AG. ApoEϪ/Ϫ mice received CAPE-supplemented chow for 12 weeks. Compliance with CAPE supplementation was confirmed by measuring the consumption of chow supplemented with CAPE every day. The average chow intake was 5 to 6 g per day in control and CAPE-supplemented groups.
Quantitation of Aortic AtherosclerosisThe extent of atherosclerosis in the mouse aorta was determined using an en-face method. 10 Aortas were fixed in paraformaldehyde and stained with oil red O. Morphometric image analysis of the captured digitali...