- Email: [email protected]
Vascular effects of step I diet in hypercholesterolemic patients with coronary artery disease
Vascular Effects of Step I Diet In Hypercholesterolemic Patients With Coronary Artery Disease Kwang Kon Koh, MD, Jeong Yeal Ahn, MD, Yu Mi Choi, Dae Sung Kim, MD, Hyung Sik Kim, MD, Tae Hoon Ahn, Eak Kyun Shin, MD We administered a step I diet to 50 hypercholesterolemic patients with coronary artery disease during 12 weeks. Compared with baseline, the step I diet significantly changed lipoprotein levels, significantly improved the percent flow-mediated dilation response to hyperemia by 32 ⴞ 7% (p <0.001), increased plasma levels of nitrate by 45 ⴞ 12% (p ⴝ 0.013), and lowered plasma levels of malondialdehyde by 7 ⴞ 4% (p ⴝ 0.011). However, the step I diet did not significantly change serologic markers of inflammation, plaque stability, and thrombosis. Step I diet therapy improved endothelium-dependent vasodilation with an increase in plasma nitrogen oxide and a decrease in oxidant stress in hypercholesterolemic patients with coronary artery disease. 䊚2003 by Excerpta Medica, Inc. (Am J Cardiol 2003;92:708–710)
holesterol level lowering in experimental models was accompanied by a decrease of vascular inC flammation, extracellular matrix, and tissue factor within atherosclerotic plaque.1,2 Accordingly, the mechanism of Step I diet therapy may be mediated by inhibiting vascular inflammation and thrombosis and stabilizing plaque. Thus, we investigated the effects of the Step I diet on lipoproteins and vasomotor function, and serologic markers of inflammation, plaque stability, and thrombosis in patients with hypercholesterolemia and coronary artery disease. Further, we investigated the regulation mechanism of these markers, which is suggested by experimental studies.3–7 •••
Fifty-two patients with angiographically documented coronary artery disease were enrolled in this study. All patients were in Canadian Cardiovascular Society class I or II. All patients were taught and placed on the American Heart Association Step I diet for 12 weeks. Briefly, the Step I diet was designed to supply total fat to ⱕ30%, saturated fat to ⬍8 to 10%, carbohydrates ⱖ55%, and cholesterol to ⬍300 mg/ day.8 All patients were told not to change lifestyle or medications except diet during the 12 weeks to avoid the effects of these factors. Patients were advised to modify their regular diet in 2 stages. The aim of stage 1 was to prepare patients to accept the detailed inFrom the Departments of Cardiology, Clinical Pathology, Nutrition, Preventive Medicine (Biostatistics), and Radiology, Gachon Medical School, Incheon, Korea. Dr. Koh’s address is: Vascular Medicine and Atherosclerosis Unit, Cardiology, Gil Heart Center, Gachon Medical School, 1198 Kuwol-dong, Namdong-gu, Incheon, Korea. E-mail: [email protected]. Manuscript received April 8, 2003; revised manuscript received and accepted June 2, 2003.
708
©2003 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 92 September 15, 2003
RD, MD,
Seung Hwan Han, MD, In Suck Choi, MD, and
structions given in the second stage. Stage 2 of the diet intervention was conducted by the dietitian (YMC) and consisted of helping patients and their families adapt their usual diet to the Step I diet. The dietitian met patients at 1, 4, and 8 weeks. Two patients dropped out because of a change in employment. Mean age of the 50 patients was 57 ⫾ 9 years and 20 (40%) were men. Mean body mass index changed from 24.9 ⫾ 0.6 at baseline to 24.4 ⫾ 0.5 at the end. Risk factors were hypertension (62%), diabetes (26%), and current smoking (30%). Most medications were -adrenergic blockers (80%), calcium channel blockers (44%), angiotensin-converting enzyme inhibitors (22%), long-acting nitrates (78%), and aspirin (84%). Vasoactive medications—including calcium channel blockers, angiotensin-converting enzyme inhibitors, and long-acting nitrates—were withheld for ⱖ24 hours before the study. All patients were taking aspirin and -blocker therapy on a long-term basis. No patients received any cholesterol-lowering agent, estrogen therapy, or antioxidant vitamin supplements during the preceding 2 months. The study was approved by the Gil Hospital Institute Review Board and all participants gave written, informed consent. Blood samples for laboratory assays were obtained at approximately 8:00 A.M. after overnight fasting at baseline and at the end of each treatment period. They were immediately coded so that investigators performing laboratory assays were totally blinded to subject identity or study sequence. Assays for lipids, fibrinogen, plasma nitrate (using the Griess reaction), malondialdehyde, monocyte chemoattractant protein-1, tumor necrosis factor (TNF)-␣, intercellular adhesion molecule type-1, matrix metalloproteinase (MMP)-9 and -3 activity, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 were performed in duplicate by enzyme-linked immunosorbent assays (R & D Systems Inc., Minneapolis, Minnesota, and BIOXYTECH LPO-586, OxisResearch, Portland, Oregon) as previously described.9 –13 Serum C-reactive protein levels were determined with an immuno-nephelometry system according to methods described by the manufacturer (Rate nephelometry, IMMAGE; Beckman Coulter, Brea, California) as previously described.13,14 The measurement range is 0.1 to 98 mg/dl. Assays for tissue factor activity and tissue factor pathway inhibitor activity were measured in duplicate by actichrome assays (American Diagnostica, Greenwich, Connecticut) as previously described.11,14 All samples from the same patient (batch samples) were measured in blinded pairs on the same enzyme-linked immunosorbent assay kit to minimize run-to-run variability. The 0002-9149/03/$–see front matter doi:10.1016/S0002-9149(03)00832-4
we used Student’s paired t or Wilcoxon’s signed rank test to compare values after baseline and Step I diet Variables Baseline Step I Diet therapy, as listed in Table 1. In the case of C-reactive protein, we anaTotal cholesterol (mg/dl) 241 ⫾ 5 221 ⫾ 5‡ Triglycerides (mg/dl) 166 ⫾ 13 182 ⫾ 14 lyzed data from 40 of 50 patients LDL cholesterol (mg/dl) 156 ⫾ 5 132 ⫾ 6‡ who had C-reactive protein values † Apo B (mg/dl) 124 ⫾ 4 112 ⫾ 3 above the lower limits of detectabilHDL cholesterol (mg/dl) 52 ⫾ 3 50 ⫾ 2 ity (0.1 mg/dl). We calculated that Apo A-1 (mg/dl) 152 ⫾ 3 143 ⫾ 3* Flow-mediated dilation (%) 4.40 ⫾ 0.23 5.42 ⫾ 0.25‡ 50 subjects will provide an 80% Nitroglycerin dilation (%) 13.40 ⫾ 0.55 13.87 ⫾ 0.52 power for detecting a difference of † Nitrate (mol/l) 68 ⫾ 5 87 ⫾ 6 absolute increase 1.0% or greater Malondialdehyde (M) 1.75 ⫾ 0.10 1.52 ⫾ 0.08† flow-mediated dilation of the braMonocyte chemoattractant protein-1 (pg/ml) 179 ⫾ 6 189 ⫾ 8 chial artery on Step I diet compared TNF-␣ (pg/ml) 2.78 ⫾ 0.12 2.94 ⫾ 0.13 Intercellular adhesion molecule-1 (ng/ml) 205 ⫾ 9 206 ⫾ 9 with baseline, with ␣ ⫽ 0.05. The C-reactive protein (mg/dl) 0.22 (0.13–0.46) 0.20 (0.13–0.27) comparison of endothelium-depenMMP-9 activity (ng/ml) 30 ⫾ 4 23 ⫾ 1 dent dilation between baseline and MMP-3 activity (ng/ml) 19 ⫾ 3 14 ⫾ 1 Step I diet therapy was prospecTIMP-1 (ng/ml) 86 ⫾ 4 89 ⫾ 4 Fibrinogen (mg/dl) 314 ⫾ 8 323 ⫾ 9 tively designated as the primary end Tissue factor activity (nM) 0.19 ⫾ 0.02 0.22 ⫾ 0.03 point of the study. Pearson’s correTissue factor pathway inhibitor activity (ng/ml) 1.22 ⫾ 0.04 1.27 ⫾ 0.04 lation coefficient analysis was used *p ⬍0.05; †p ⬍0.01;‡p ⬍0.001 versus baseline. to assess associations between meaValues are expressed as means ⫾ SEM or median (range 25% to 75%). sured parameters. A p value ⬍0.05 was considered significant. Compared with baseline, diet significantly changed lipoprotein levels. As expected, diet decreased total cholesterol and low-density lipoprotein (LDL) cholesterol (p ⬍0.001 for both), apolipoprotein B (p ⫽ 0.005), high-density lipoprotein (HDL) cholesterol (p ⫽ 0.087), and apolipoprotein A-I (p ⫽ 0.016) and tended to increase triglycerides (p ⫽ 0.078). Diet significantly improved the percent flow-mediated dilator response to hyperemia by 32 ⫾ 7% (p ⬍0.001; Figure 1); however, the brachial artery dilator response to nitroglycerin did not change significantly (p ⫽ 0.120). Diet significantly increased plasma nitrate levels by 45 ⫾ 12% from their respective baseline levels (p ⫽ FIGURE 1. Flow-mediated dilation and plasma malondialdehyde levels on Step I diet. 0.013) and significantly lowered Compared with baseline, Step I diet significantly improved the percent flow-mediated plasma malondialdehyde levels by dilator response to hyperemia with a decrease of plasma malondialdehyde levels. 7 ⫾ 4% from their respective baseMean values are identified by open circles. line levels (p ⫽ 0.011; Figure 1). Compared with baseline, diet did interassay and intra-assay coefficients of variation not significantly change plasma levels of inflammation markers. Compared with baseline, diet did not signifiwere ⬍6%. Imaging studies of the right brachial artery were cantly change plasma levels of TNF-␣ by 9 ⫾ 3% (p ⫽ performed using an ATL HDI 3000 ultrasound ma- 0.174), MMP-9 activity by 5 ⫾ 5% (p ⫽ 0.154), MMP-3 chine (Bothell, Washington) equipped with a 10-MHz activity by 3 ⫾ 6% (p ⫽ 0.260), or TIMP-1 by 5 ⫾ 3% linear-array transducer, based on a previously pub- (p ⫽ 0.341). Compared with baseline, diet decreased lished technique.10,11,13 Measurements were per- serum levels of C-reactive protein from 0.22 to 0.20 formed by 2 independent investigators (SHH and mg/dl (p ⫽ 0.323). Diet did not significantly change HSK) blinded to the subject’s identity and medication fibrinogen by 4 ⫾ 2% (p ⫽ 0.229), plasma levels of tissue factor activity by 28 ⫾ 12% (p ⫽ 0.456), and status. Data are expressed as mean ⫾ SEM or median tissue factor pathway inhibitor activity by 5 ⫾ 3% (p ⫽ (range 25% to 75%). After testing data for normality, 0.346) relative to baseline measurements. TABLE 1 Effects of Step I Diet on Patients With Hypercholesterolemia and Coronary Artery Disease (n ⫽ 50)
BRIEF REPORTS
709
There were no significant correlations between the degree of changes in lipoprotein levels and the degree of changes in flow-mediated dilation. There were significant correlations between changes in LDL cholesterol and changes in MMP-9 activity (r ⫽ 0.450, p ⫽ 0.014). •••
In the present investigation, we observed that Step I diet therapy improved endothelium-dependent vasodilation through an increase of plasma nitrogen oxide and decrease of oxidant stress; however, it did not significantly change the serologic markers of inflammation, plaque stability, and thrombosis. To gain insight into the effects of potential vasculoprotective mechanisms of Step I diet, we measured vasomotor function, plasma TNF-␣, and markers of plaque stability. In patients with acute coronary syndrome or Kawasaki’s disease, high plasma levels of MMP-9 and TIMP-1 suggested a role of the proteolytic enzyme in the development of acute coronary disease.15,16 Decreasing blood LDL cholesterol levels may facilitate plaque stability, either through a reduction in size or by an alteration of the physiochemical properties of lipid cores.17 However, changes in plaque size by lipid lowering tend to occur over an extended time and are quite minimal, as assessed by angiography. Rather, the clinical benefits from lipid lowering are probably due to decreases in macrophage accumulation in atherosclerotic lesions and inhibition of MMP production by activated macrophages. In this regard, Aikawa at al1 demonstrated that intimal smooth muscle cells in the low cholesterol group displayed reduced expression of MMP-9 compared with the high cholesterol groups. Xu et al3 demonstrated that oxidized LDL upregulated MMP-9 expression while reducing TIMP-1 in monocyte-derived macrophages. Furthermore, HDL abrogated oxidized LDL-induced MMP-9 expression. In the present investigation, we observed significant correlations between the degree of changes in LDL cholesterol and the degree of changes in MMP-9 activity while on the Step I diet. However, we did not observe significant correlations between other lipoprotein levels and MMP-9 activity during the diet. Meanwhile, endothelial nitric oxide synthase gene transfer significantly decreased MMP-2 and MMP-9 activities simultaneously with increase of TIMP-2 levels in the conditioned medium.4 Furthermore, TNF-␣, a proinflammatory cytokine, stimulated the synthesis and secretion of MMP-9.5 However, we did not observe significant correlations between the degree of changes in flow-mediated dilation or TNF-␣ and the
710 THE AMERICAN JOURNAL OF CARDIOLOGY姞
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degree of changes in MMP-9 activity on the Step I diet. Acknowledgment: We express our gratitude to Han Gyu Kim, MT, Sang Kyoon Kwon, MT, Mi Jung Kim, MT, and Soo Jin Kim, RN, for their assistance.
1. Aikawa M, Rabkin E, Okada Y, Voglic SJ, Clinton SK, Brinckerhoff CE, Sukhova GK, Libby P. Lipid lowering by diet reduces matrix metalloproteinase activity and increases collagen content of rabbit atheroma. Circulation 1998;97: 2433–2444. 2. Aikawa M, Voglic SJ, Sugiyama S, Rabkin E, Taubman MB, Fallon JT, Libby P. Dietary lipid lowering reduces tissue factor expression in rabbit atheroma. Circulation 1999;100:1215–1222. 3. Xu XP, Meisel SR, Ong JM, Kaul S, Cercek B, Rajavashisth TB, Sharifi B, Shah PK. Oxidized low-density lipoprotein regulates matrix metalloproteinase-9 and its tissue inhibitor in human monocyte-derived macrophages. Circulation 1999;99:993–998. 4. Gurjar MV, Sharma RV, Bhalla RC. ENOS gene transfer inhibits smooth muscle cell migration and MMP-2 and MMP-9 activity. Arterioscler Thromb Vasc Biol 1999;19:2871–2877. 5. Galis ZS, Sukhova GK, Lark MW, Libby P. Increased expression of matrix metalloproteinases and matrix degrading activity in vulnerable regions human atherosclerotic plaques. J Clin Invest 1994;94:2493–2503. 6. Brand K, Banka CL, Mackman N, Terkeltaub RA, Fan S-T, Curtiss LK. Oxidized LDL enhances lipopolysaccharide-induced tissue factor expression in human adherent monocytes. Arterioscler Thromb Vasc Biol 1994;14:790 –797. 7. Cermak J, Key NS, Bach RR, Balla J, Jacob HS, Vercellotti GM. C-reactive protein induces human peripheral blood monocytes to synthesize tissue factor. Blood 1993;82:513–520. 8. Smith SC Jr, Blair SN, Criqui MH, Fletcher GF, Fuster V, Gersh BJ, Gotto AM, Gould KL, Greenland P, Grundy SM, et al. Preventing heart attack and death in patients with coronary disease. Circulation 1995;92:2–4. 9. Koh KK, Son JW, Ahn JY, Choi YM, Jin DK, Park GS, Choi IS, Sohn MS, Shin EK. Non-lipid effects of statin on hypercholesterolemic patients established to have coronary artery disease who remained hypercholesterolemic while eating a step-II diet. Coron Artery Dis 2001;12:305–311. 10. Koh KK, Cardillo C, Bui MN, Hathaway L, Csako G, Waclawiw MA, Panza JA, Cannon RO III. The effect of estrogen and cholesterol-lowering therapies on vascular function in hypercholesterolemic postmenopausal women. Circulation 1999;99:354 –360. 11. Koh KK, Jin DK, Yang SH, Lee SK, Hwang HY, Kang MH, Kim W, Kim DS, Choi IS, Shin EK. Vascular effects of synthetic or natural progestagen combined with conjugated equine estrogen in healthy postmenopausal women. Circulation 2001;103:1961–1966. 12. Koh KK, Mincemoyer R, Bui MN, Csako G, Pucino F, Guetta V, Waclawiw M, Cannon RO III. Effects of hormone-replacement therapy on fibrinolysis in postmenopausal women. N Engl J Med 1997;336:683–690. 13. Koh KK, Son JW, Ahn JY, Jin DK, Kim HS, Choi YM, Kim DS, Jeong EM, Park GS, Choi IS, Shin EK. Comparative effects of diet and statin on nitric oxide bioactivity and matrix metalloproteinases in hypercholesterolemic patients with coronary artery disease. Arterioscler Thromb Vasc Biol 2002;22:e19 –e23. 14. Koh KK, Ahn JY, Kim DS, Ryu WS, Shin M-S, Ahn TH, Choi IS, Shin EK. Effect of hormone replacement therapy on tissue factor activity, C-reactive protein, and tissue factor pathway inhibitor. Am J Cardiol 2003;91:371–373. 15. Inokubo Y, Hanada H, Ishizaka H, Fukushi T, Kamada T, Okumura K. Plasma levels of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 are increased in the coronary circulation in patients with acute coronary syndrome. Am Heart J 2001;141:211–217. 16. Senzaki H, Masutani S, Kobayashi J, Kobayashi T, Nakano H, Nagasaka H, Sasaki N, Asano H, Kyo S, Yokote Y. Circulating matrix metalloproteinases and their inhibitors in patients with Kawasaki disease. Circulation 2001;104:860 – 863. 17. Koh KK. Effects of statins on vascular wall: vasomotor function, inflammation, and plaque stability. Cardiovasc Res 2000;47:648 –657.
SEPTEMBER 15, 2003
holesterol level lowering in experimental models was accompanied by a decrease of vascular inC flammation, extracellular matrix, and tissue factor within atherosclerotic plaque.1,2 Accordingly, the mechanism of Step I diet therapy may be mediated by inhibiting vascular inflammation and thrombosis and stabilizing plaque. Thus, we investigated the effects of the Step I diet on lipoproteins and vasomotor function, and serologic markers of inflammation, plaque stability, and thrombosis in patients with hypercholesterolemia and coronary artery disease. Further, we investigated the regulation mechanism of these markers, which is suggested by experimental studies.3–7 •••
Fifty-two patients with angiographically documented coronary artery disease were enrolled in this study. All patients were in Canadian Cardiovascular Society class I or II. All patients were taught and placed on the American Heart Association Step I diet for 12 weeks. Briefly, the Step I diet was designed to supply total fat to ⱕ30%, saturated fat to ⬍8 to 10%, carbohydrates ⱖ55%, and cholesterol to ⬍300 mg/ day.8 All patients were told not to change lifestyle or medications except diet during the 12 weeks to avoid the effects of these factors. Patients were advised to modify their regular diet in 2 stages. The aim of stage 1 was to prepare patients to accept the detailed inFrom the Departments of Cardiology, Clinical Pathology, Nutrition, Preventive Medicine (Biostatistics), and Radiology, Gachon Medical School, Incheon, Korea. Dr. Koh’s address is: Vascular Medicine and Atherosclerosis Unit, Cardiology, Gil Heart Center, Gachon Medical School, 1198 Kuwol-dong, Namdong-gu, Incheon, Korea. E-mail: [email protected]. Manuscript received April 8, 2003; revised manuscript received and accepted June 2, 2003.
708
©2003 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 92 September 15, 2003
RD, MD,
Seung Hwan Han, MD, In Suck Choi, MD, and
structions given in the second stage. Stage 2 of the diet intervention was conducted by the dietitian (YMC) and consisted of helping patients and their families adapt their usual diet to the Step I diet. The dietitian met patients at 1, 4, and 8 weeks. Two patients dropped out because of a change in employment. Mean age of the 50 patients was 57 ⫾ 9 years and 20 (40%) were men. Mean body mass index changed from 24.9 ⫾ 0.6 at baseline to 24.4 ⫾ 0.5 at the end. Risk factors were hypertension (62%), diabetes (26%), and current smoking (30%). Most medications were -adrenergic blockers (80%), calcium channel blockers (44%), angiotensin-converting enzyme inhibitors (22%), long-acting nitrates (78%), and aspirin (84%). Vasoactive medications—including calcium channel blockers, angiotensin-converting enzyme inhibitors, and long-acting nitrates—were withheld for ⱖ24 hours before the study. All patients were taking aspirin and -blocker therapy on a long-term basis. No patients received any cholesterol-lowering agent, estrogen therapy, or antioxidant vitamin supplements during the preceding 2 months. The study was approved by the Gil Hospital Institute Review Board and all participants gave written, informed consent. Blood samples for laboratory assays were obtained at approximately 8:00 A.M. after overnight fasting at baseline and at the end of each treatment period. They were immediately coded so that investigators performing laboratory assays were totally blinded to subject identity or study sequence. Assays for lipids, fibrinogen, plasma nitrate (using the Griess reaction), malondialdehyde, monocyte chemoattractant protein-1, tumor necrosis factor (TNF)-␣, intercellular adhesion molecule type-1, matrix metalloproteinase (MMP)-9 and -3 activity, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 were performed in duplicate by enzyme-linked immunosorbent assays (R & D Systems Inc., Minneapolis, Minnesota, and BIOXYTECH LPO-586, OxisResearch, Portland, Oregon) as previously described.9 –13 Serum C-reactive protein levels were determined with an immuno-nephelometry system according to methods described by the manufacturer (Rate nephelometry, IMMAGE; Beckman Coulter, Brea, California) as previously described.13,14 The measurement range is 0.1 to 98 mg/dl. Assays for tissue factor activity and tissue factor pathway inhibitor activity were measured in duplicate by actichrome assays (American Diagnostica, Greenwich, Connecticut) as previously described.11,14 All samples from the same patient (batch samples) were measured in blinded pairs on the same enzyme-linked immunosorbent assay kit to minimize run-to-run variability. The 0002-9149/03/$–see front matter doi:10.1016/S0002-9149(03)00832-4
we used Student’s paired t or Wilcoxon’s signed rank test to compare values after baseline and Step I diet Variables Baseline Step I Diet therapy, as listed in Table 1. In the case of C-reactive protein, we anaTotal cholesterol (mg/dl) 241 ⫾ 5 221 ⫾ 5‡ Triglycerides (mg/dl) 166 ⫾ 13 182 ⫾ 14 lyzed data from 40 of 50 patients LDL cholesterol (mg/dl) 156 ⫾ 5 132 ⫾ 6‡ who had C-reactive protein values † Apo B (mg/dl) 124 ⫾ 4 112 ⫾ 3 above the lower limits of detectabilHDL cholesterol (mg/dl) 52 ⫾ 3 50 ⫾ 2 ity (0.1 mg/dl). We calculated that Apo A-1 (mg/dl) 152 ⫾ 3 143 ⫾ 3* Flow-mediated dilation (%) 4.40 ⫾ 0.23 5.42 ⫾ 0.25‡ 50 subjects will provide an 80% Nitroglycerin dilation (%) 13.40 ⫾ 0.55 13.87 ⫾ 0.52 power for detecting a difference of † Nitrate (mol/l) 68 ⫾ 5 87 ⫾ 6 absolute increase 1.0% or greater Malondialdehyde (M) 1.75 ⫾ 0.10 1.52 ⫾ 0.08† flow-mediated dilation of the braMonocyte chemoattractant protein-1 (pg/ml) 179 ⫾ 6 189 ⫾ 8 chial artery on Step I diet compared TNF-␣ (pg/ml) 2.78 ⫾ 0.12 2.94 ⫾ 0.13 Intercellular adhesion molecule-1 (ng/ml) 205 ⫾ 9 206 ⫾ 9 with baseline, with ␣ ⫽ 0.05. The C-reactive protein (mg/dl) 0.22 (0.13–0.46) 0.20 (0.13–0.27) comparison of endothelium-depenMMP-9 activity (ng/ml) 30 ⫾ 4 23 ⫾ 1 dent dilation between baseline and MMP-3 activity (ng/ml) 19 ⫾ 3 14 ⫾ 1 Step I diet therapy was prospecTIMP-1 (ng/ml) 86 ⫾ 4 89 ⫾ 4 Fibrinogen (mg/dl) 314 ⫾ 8 323 ⫾ 9 tively designated as the primary end Tissue factor activity (nM) 0.19 ⫾ 0.02 0.22 ⫾ 0.03 point of the study. Pearson’s correTissue factor pathway inhibitor activity (ng/ml) 1.22 ⫾ 0.04 1.27 ⫾ 0.04 lation coefficient analysis was used *p ⬍0.05; †p ⬍0.01;‡p ⬍0.001 versus baseline. to assess associations between meaValues are expressed as means ⫾ SEM or median (range 25% to 75%). sured parameters. A p value ⬍0.05 was considered significant. Compared with baseline, diet significantly changed lipoprotein levels. As expected, diet decreased total cholesterol and low-density lipoprotein (LDL) cholesterol (p ⬍0.001 for both), apolipoprotein B (p ⫽ 0.005), high-density lipoprotein (HDL) cholesterol (p ⫽ 0.087), and apolipoprotein A-I (p ⫽ 0.016) and tended to increase triglycerides (p ⫽ 0.078). Diet significantly improved the percent flow-mediated dilator response to hyperemia by 32 ⫾ 7% (p ⬍0.001; Figure 1); however, the brachial artery dilator response to nitroglycerin did not change significantly (p ⫽ 0.120). Diet significantly increased plasma nitrate levels by 45 ⫾ 12% from their respective baseline levels (p ⫽ FIGURE 1. Flow-mediated dilation and plasma malondialdehyde levels on Step I diet. 0.013) and significantly lowered Compared with baseline, Step I diet significantly improved the percent flow-mediated plasma malondialdehyde levels by dilator response to hyperemia with a decrease of plasma malondialdehyde levels. 7 ⫾ 4% from their respective baseMean values are identified by open circles. line levels (p ⫽ 0.011; Figure 1). Compared with baseline, diet did interassay and intra-assay coefficients of variation not significantly change plasma levels of inflammation markers. Compared with baseline, diet did not signifiwere ⬍6%. Imaging studies of the right brachial artery were cantly change plasma levels of TNF-␣ by 9 ⫾ 3% (p ⫽ performed using an ATL HDI 3000 ultrasound ma- 0.174), MMP-9 activity by 5 ⫾ 5% (p ⫽ 0.154), MMP-3 chine (Bothell, Washington) equipped with a 10-MHz activity by 3 ⫾ 6% (p ⫽ 0.260), or TIMP-1 by 5 ⫾ 3% linear-array transducer, based on a previously pub- (p ⫽ 0.341). Compared with baseline, diet decreased lished technique.10,11,13 Measurements were per- serum levels of C-reactive protein from 0.22 to 0.20 formed by 2 independent investigators (SHH and mg/dl (p ⫽ 0.323). Diet did not significantly change HSK) blinded to the subject’s identity and medication fibrinogen by 4 ⫾ 2% (p ⫽ 0.229), plasma levels of tissue factor activity by 28 ⫾ 12% (p ⫽ 0.456), and status. Data are expressed as mean ⫾ SEM or median tissue factor pathway inhibitor activity by 5 ⫾ 3% (p ⫽ (range 25% to 75%). After testing data for normality, 0.346) relative to baseline measurements. TABLE 1 Effects of Step I Diet on Patients With Hypercholesterolemia and Coronary Artery Disease (n ⫽ 50)
BRIEF REPORTS
709
There were no significant correlations between the degree of changes in lipoprotein levels and the degree of changes in flow-mediated dilation. There were significant correlations between changes in LDL cholesterol and changes in MMP-9 activity (r ⫽ 0.450, p ⫽ 0.014). •••
In the present investigation, we observed that Step I diet therapy improved endothelium-dependent vasodilation through an increase of plasma nitrogen oxide and decrease of oxidant stress; however, it did not significantly change the serologic markers of inflammation, plaque stability, and thrombosis. To gain insight into the effects of potential vasculoprotective mechanisms of Step I diet, we measured vasomotor function, plasma TNF-␣, and markers of plaque stability. In patients with acute coronary syndrome or Kawasaki’s disease, high plasma levels of MMP-9 and TIMP-1 suggested a role of the proteolytic enzyme in the development of acute coronary disease.15,16 Decreasing blood LDL cholesterol levels may facilitate plaque stability, either through a reduction in size or by an alteration of the physiochemical properties of lipid cores.17 However, changes in plaque size by lipid lowering tend to occur over an extended time and are quite minimal, as assessed by angiography. Rather, the clinical benefits from lipid lowering are probably due to decreases in macrophage accumulation in atherosclerotic lesions and inhibition of MMP production by activated macrophages. In this regard, Aikawa at al1 demonstrated that intimal smooth muscle cells in the low cholesterol group displayed reduced expression of MMP-9 compared with the high cholesterol groups. Xu et al3 demonstrated that oxidized LDL upregulated MMP-9 expression while reducing TIMP-1 in monocyte-derived macrophages. Furthermore, HDL abrogated oxidized LDL-induced MMP-9 expression. In the present investigation, we observed significant correlations between the degree of changes in LDL cholesterol and the degree of changes in MMP-9 activity while on the Step I diet. However, we did not observe significant correlations between other lipoprotein levels and MMP-9 activity during the diet. Meanwhile, endothelial nitric oxide synthase gene transfer significantly decreased MMP-2 and MMP-9 activities simultaneously with increase of TIMP-2 levels in the conditioned medium.4 Furthermore, TNF-␣, a proinflammatory cytokine, stimulated the synthesis and secretion of MMP-9.5 However, we did not observe significant correlations between the degree of changes in flow-mediated dilation or TNF-␣ and the
710 THE AMERICAN JOURNAL OF CARDIOLOGY姞
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degree of changes in MMP-9 activity on the Step I diet. Acknowledgment: We express our gratitude to Han Gyu Kim, MT, Sang Kyoon Kwon, MT, Mi Jung Kim, MT, and Soo Jin Kim, RN, for their assistance.
1. Aikawa M, Rabkin E, Okada Y, Voglic SJ, Clinton SK, Brinckerhoff CE, Sukhova GK, Libby P. Lipid lowering by diet reduces matrix metalloproteinase activity and increases collagen content of rabbit atheroma. Circulation 1998;97: 2433–2444. 2. Aikawa M, Voglic SJ, Sugiyama S, Rabkin E, Taubman MB, Fallon JT, Libby P. Dietary lipid lowering reduces tissue factor expression in rabbit atheroma. Circulation 1999;100:1215–1222. 3. Xu XP, Meisel SR, Ong JM, Kaul S, Cercek B, Rajavashisth TB, Sharifi B, Shah PK. Oxidized low-density lipoprotein regulates matrix metalloproteinase-9 and its tissue inhibitor in human monocyte-derived macrophages. Circulation 1999;99:993–998. 4. Gurjar MV, Sharma RV, Bhalla RC. ENOS gene transfer inhibits smooth muscle cell migration and MMP-2 and MMP-9 activity. Arterioscler Thromb Vasc Biol 1999;19:2871–2877. 5. Galis ZS, Sukhova GK, Lark MW, Libby P. Increased expression of matrix metalloproteinases and matrix degrading activity in vulnerable regions human atherosclerotic plaques. J Clin Invest 1994;94:2493–2503. 6. Brand K, Banka CL, Mackman N, Terkeltaub RA, Fan S-T, Curtiss LK. Oxidized LDL enhances lipopolysaccharide-induced tissue factor expression in human adherent monocytes. Arterioscler Thromb Vasc Biol 1994;14:790 –797. 7. Cermak J, Key NS, Bach RR, Balla J, Jacob HS, Vercellotti GM. C-reactive protein induces human peripheral blood monocytes to synthesize tissue factor. Blood 1993;82:513–520. 8. Smith SC Jr, Blair SN, Criqui MH, Fletcher GF, Fuster V, Gersh BJ, Gotto AM, Gould KL, Greenland P, Grundy SM, et al. Preventing heart attack and death in patients with coronary disease. Circulation 1995;92:2–4. 9. Koh KK, Son JW, Ahn JY, Choi YM, Jin DK, Park GS, Choi IS, Sohn MS, Shin EK. Non-lipid effects of statin on hypercholesterolemic patients established to have coronary artery disease who remained hypercholesterolemic while eating a step-II diet. Coron Artery Dis 2001;12:305–311. 10. Koh KK, Cardillo C, Bui MN, Hathaway L, Csako G, Waclawiw MA, Panza JA, Cannon RO III. The effect of estrogen and cholesterol-lowering therapies on vascular function in hypercholesterolemic postmenopausal women. Circulation 1999;99:354 –360. 11. Koh KK, Jin DK, Yang SH, Lee SK, Hwang HY, Kang MH, Kim W, Kim DS, Choi IS, Shin EK. Vascular effects of synthetic or natural progestagen combined with conjugated equine estrogen in healthy postmenopausal women. Circulation 2001;103:1961–1966. 12. Koh KK, Mincemoyer R, Bui MN, Csako G, Pucino F, Guetta V, Waclawiw M, Cannon RO III. Effects of hormone-replacement therapy on fibrinolysis in postmenopausal women. N Engl J Med 1997;336:683–690. 13. Koh KK, Son JW, Ahn JY, Jin DK, Kim HS, Choi YM, Kim DS, Jeong EM, Park GS, Choi IS, Shin EK. Comparative effects of diet and statin on nitric oxide bioactivity and matrix metalloproteinases in hypercholesterolemic patients with coronary artery disease. Arterioscler Thromb Vasc Biol 2002;22:e19 –e23. 14. Koh KK, Ahn JY, Kim DS, Ryu WS, Shin M-S, Ahn TH, Choi IS, Shin EK. Effect of hormone replacement therapy on tissue factor activity, C-reactive protein, and tissue factor pathway inhibitor. Am J Cardiol 2003;91:371–373. 15. Inokubo Y, Hanada H, Ishizaka H, Fukushi T, Kamada T, Okumura K. Plasma levels of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 are increased in the coronary circulation in patients with acute coronary syndrome. Am Heart J 2001;141:211–217. 16. Senzaki H, Masutani S, Kobayashi J, Kobayashi T, Nakano H, Nagasaka H, Sasaki N, Asano H, Kyo S, Yokote Y. Circulating matrix metalloproteinases and their inhibitors in patients with Kawasaki disease. Circulation 2001;104:860 – 863. 17. Koh KK. Effects of statins on vascular wall: vasomotor function, inflammation, and plaque stability. Cardiovasc Res 2000;47:648 –657.
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