|
|
||||||||||
|
J Am Coll Cardiol, 2002; 39:957-962 © 2002 by the American College of Cardiology Foundation |
* First Department of Internal Medicine, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, Japan
Manuscript received July 10, 2001; revised manuscript received December 14, 2001, accepted December 18, 2001.
* Reprint requests and correspondence: Dr. Takayoshi Tsutamoto, First Department of Internal Medicine, Shiga University of Medical Science, Tsukinowa, Seta, Otsu 520-2192, Japan.
tutamoto{at}belle.shiga-med.ac.jp
| Abstract |
|---|
|
|
|---|
BACKGROUND: Oxidative stress appears to play a role in the pathophysiology of CHF. We have recently reported the usefulness of plasma oxLDL as a marker of oxidative stress in CHF patients with dilated cardiomyopathy.
METHODS: We measured the plasma level of oxLDL by sandwich enzyme-linked immunosorbent assay using a specific monoclonal antibody against oxLDL in 18 age-matched normal subjects and in 84 patients with chronic CHF (New York Heart Association functional class II to IV) and monitored them prospectively for a mean follow-up period of 780 days.
RESULTS: Plasma oxLDL level was significantly higher in severe CHF patients than in control subjects and mild CHF patients. A significant negative correlation existed between the plasma level of oxLDL and left ventricular ejection fraction (LVEF) and a significant positive correlation between the plasma level of oxLDL and plasma norepinephrine level. Twenty-six patients had cardiac events; 14 had cardiac death and 12 were hospitalized for heart failure or other cardiovascular events. Among 10 variables including LVEF and neurohumoral factors, only high plasma levels of brain natriuretic peptide and oxLDL were shown to be independent predictors of mortality.
CONCLUSIONS: These results indicate that the plasma level of oxLDL is a useful predictor of mortality in patients with CHF, suggesting that oxidative stress plays an important role in the pathophysiology of CHF.
| |||||||||||||||||||||||
Therefore, we evaluated the relationship between the plasma level of oxLDL and the other markers of the severity of CHF, and we assessed whether plasma oxLDL can provide prognostic information independent of clinical and neurohumoral factors previously associated with a poor prognosis in CHF patients.
| Methods |
|---|
|
|
|---|
Study protocol. All patients had rested in bed in the supine position for at least 30 min early in the morning. Blood samples for measuring plasma level of oxLDL, norepinephrine (NE), brain natriuretic peptide (BNP) and serum levels of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein (LDL) cholesterol and triglycerides were collected from the peripheral vein. The LVEF was measured by echocardiography using the biplane disc summation method (Simpsons rule) or left ventriculography in a blinded fashion. Then, the 84 patients were entered and followed prospectively. All surviving patients were monitored prospectively for >589 days, for a mean follow-up period of 780 ± 15.6 days (range 589 to 984 days). The end points, which were judged independently by researchers, were cardiac death (worsening CHF, lethal MI or sudden death) or hospitalization for worsening CHF, MI or fatal arrhythmia.
Measurements of oxLDL, NE and BNP. Blood for measurement of the plasma level of oxLDL was placed into a plain tube, centrifuged at 3,000 rpm for 15 min at 4°C, and the plasma thus obtained was stored at 4°C until assayed. Plasma oxLDL levels were measured using a specific immunometric assay for human oxLDL using a kit (Kyowa Medex, Tokyo, Japan) (10,11), which employed a modification of a method previously reported (10). Briefly, this assay system uses two antibodies against human oxLDL, one recognizing a monoclonal antibody against oxidized phosphatidylcholine (10) and the other a polyclonal antibody against human apolipoprotein B, respectively, and measures oxLDL by sandwiching it between the two antibodies (11,12). Plasma concentration of BNP was measured with a specific immunoradiometric assay using a commercial kit (Shionogi, Osaka, Japan) as previously reported (13). Plasma level of NE was measured with high-performance liquid chromatography as previously reported (13).
Statistical analysis. All results are expressed as the mean ± SEM. Univariate analyses were performed using the Student t test. Comparisons between multiple groups were determined by one-way analysis of variance with the Scheffé F test. Categorical data were compared against a chi-square distribution. Linear regression analysis was used to determine the relationship between continuous variables. To ascertain whether measurement of plasma level of oxLDL is useful for predicting morbidity and mortality in patients with chronic CHF, 10 variables were entered into a Cox proportional hazard analysis. Kaplan-Meier analysis was performed on the cumulative cardiac event-free rates in patients with chronic CHF stratified into two groups based on the median plasma oxLDL level. A value of p < 0.05 was considered significant.
| Results |
|---|
|
|
|---|
|
|
|
|
|
|
| Discussion |
|---|
|
|
|---|
Plasma level of oxLDL increased in patients with CHF. In this study, plasma oxLDL level increased in the peripheral vein in patients with chronic CHF caused by DCM or ischemic cardiomyopathy. The elevated level of plasma oxLDL in the peripheral vein may reflect the increased oxidation status in the failing myocardium or poorly perfused peripheral muscles in patients with CHF. We recently reported that the plasma level of oxLDL measured in the coronary sinus in DCM patients with CHF was significantly higher than that in the aortic root, and there was no difference in the plasma oxLDL level between in the aortic root and in the femoral vein, suggesting that the source of the increase in plasma oxLDL is of myocardial origin rather than peripheral origin. In contrast, thiobarbituric acid-reacting substances (TBARS) measured in the same patients did not show an increase in plasma level as plasma oxLDL did, suggesting that the plasma oxLDL is a sensitive marker of oxidative stress in the heart of DCM patients, and free radicals such as superoxide produced in the failing myocardium may oxidize LDL cholesterol (12).
The plasma level of oxLDL increased with the severity of CHF in patients with DCM and ischemic cardiomyopathy. In patients with coronary artery disease, the circulating oxLDL may also be derived from coronary atherosclerotic lesions, especially foam-cell-rich unstable plaques in acute coronary syndrome, because it was not increased in patients with stable coronary artery disease (14).
In the present study, plasma oxLDL was measured using the same antibody as the previous study (14), and all 49 patients with ischemic cardiomyopathy had an MI >3 months before the study, and had no clinical signs of ischemia such as chest pain and diagnostic ST-T changes on electrocardiogram by exercise test after MI. Therefore, the increased plasma oxLDL in patients with ischemic cardiomyopathy in the present study was considered mainly due to CHF. Indeed, no ischemic cardiac events were associated with acute coronary syndrome in most patients during the follow-up period.
Plasma level of oxLDL as an independent prognostic predictor in patients with chronic CHF. Increased biochemical markers of oxidative stress measured in peripheral blood and pericardial effusion in patients with CHF have been reported to correlate with functional class (9,15) and inversely with LVEF (3,12). Our findings are consistent with those reports. Hence, it is suggested that oxidative stress is an important factor in the progression of heart failure. However, the relationship between the biochemical markers of oxidative stress and the prognosis of CHF remains unknown. Our study reports for the first time that the plasma level of oxLDL, a clinical marker of oxidative stress, may be a useful prognostic predictor in patients with CHF. In the present study, plasma levels of BNP and NE and low LVEF were prognostic factors in CHF by univariate analysis as previously reported (16,17). However, according to stepwise multivariate analysis, a high plasma level of oxLDL was a significant independent predictor of mortality, suggesting that oxidative stress is an important prognostic factor in patients with CHF.
Recent reports suggest that myocardial injury caused by free radicals lead to depressed contractile function and myocardial remodeling (4,5). Many factors related to the progression of heart failure, such as neurohumoral factors, including catecholamine (18), angiotensin II (19), cytokines (20) and myocardial mechanical stretch (21), which can induce natriuretic peptide production, are closely linked to free radical formation and oxidative stress at the cellular and molecular levels. Angiotensin-converting enzyme inhibitors and beta-blockers, which have been proven to reduce mortality in patients with chronic CHF, were reported to protect the failing heart partly because of the reduction of myocardial oxidative stress.
Study limitations. In the present study, we did not measure other clinical biochemical markers of oxidative stress. Further studies are needed to determine the comparative prognostic value of other markers; however, plasma oxLDL was a sensitive marker compared with TBARS as previously reported (12). Further studies are needed to clarify the role of repetitive measurement of plasma oxLDL before and after treatments, such as carvedilol, angiotensin-converting enzyme inhibitors, and antioxidants in determining the prognosis of CHF patients.
Conclusions. The plasma level of oxLDL, a marker of oxidative stress, increased with the severity of CHF. A significant correlation existed between the plasma level of oxLDL, LVEF and NE. A high plasma oxLDL level is an independent risk factor for mortality and morbidity in patients with CHF, suggesting that oxidative stress plays an important role in the pathophysiology of CHF.
| Acknowledgments |
|---|
| Footnotes |
|---|
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
E. R. Rietzschel, M. Langlois, M. L. De Buyzere, P. Segers, D. De Bacquer, S. Bekaert, L. Cooman, P. Van Oostveldt, P. Verdonck, G. G. De Backer, et al. Oxidized Low-Density Lipoprotein Cholesterol Is Associated With Decreases in Cardiac Function Independent of Vascular Alterations Hypertension, September 1, 2008; 52(3): 535 - 541. [Abstract] [Full Text] [PDF] |
||||
![]() |
W.H. W. Tang, W. Tong, R. W. Troughton, M. G. Martin, K. Shrestha, A. Borowski, S. Jasper, S. L. Hazen, and A. L. Klein Prognostic Value and Echocardiographic Determinants of Plasma Myeloperoxidase Levels in Chronic Heart Failure J. Am. Coll. Cardiol., June 19, 2007; 49(24): 2364 - 2370. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. J. Dzau, E. M. Antman, H. R. Black, D. L. Hayes, J. E. Manson, J. Plutzky, J. J. Popma, and W. Stevenson The Cardiovascular Disease Continuum Validated: Clinical Evidence of Improved Patient Outcomes: Part II: Clinical Trial Evidence (Acute Coronary Syndromes Through Renal Disease) and Future Directions Circulation, December 19, 2006; 114(25): 2871 - 2891. [Full Text] [PDF] |
||||
![]() |
A. Svatikova, R. Wolk, L. O. Lerman, L. A. Juncos, E. L. Greene, J. P. McConnell, and V. K. Somers Oxidative stress in obstructive sleep apnoea Eur. Heart J., November 2, 2005; 26(22): 2435 - 2439. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Meyer, D. Mortl, K. Strecker, M. Hulsmann, V. Kulemann, T. Neunteufl, R. Pacher, and R. Berger Flow-Mediated Vasodilation Predicts Outcome in Patients With Chronic Heart Failure: Comparison With B-Type Natriuretic Peptide J. Am. Coll. Cardiol., September 20, 2005; 46(6): 1011 - 1018. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Zorn-Pauly, P. Schaffer, B. Pelzmann, E. Bernhart, G. Wei, P. Lang, G. Ledinski, J. Greilberger, B. Koidl, and G. Jurgens Oxidized LDL induces ventricular myocyte damage and abnormal electrical activity-role of lipid hydroperoxides Cardiovasc Res, April 1, 2005; 66(1): 74 - 83. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. A Doust, E. Pietrzak, A. Dobson, and P. Glasziou How well does B-type natriuretic peptide predict death and cardiac events in patients with heart failure: systematic review BMJ, March 19, 2005; 330(7492): 625. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. M. Stuveling, S. J. L. Bakker, H. L. Hillege, P. E. de Jong, R. O. B. Gans, and D. de Zeeuw Biochemical risk markers: a novel area for better prediction of renal risk? Nephrol. Dial. Transplant., March 1, 2005; 20(3): 497 - 508. [Full Text] [PDF] |
||||
![]() |
C. Bell, J. M. Carson, N. W. Motte, and D. R. Seals Ascorbic acid does not affect the age-associated reduction in maximal cardiac output and oxygen consumption in healthy adults J Appl Physiol, March 1, 2005; 98(3): 845 - 849. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. M Ridker, N. J. Brown, D. E. Vaughan, D. G. Harrison, and J. L. Mehta Established and Emerging Plasma Biomarkers in the Prediction of First Atherothrombotic Events Circulation, June 29, 2004; 109(25_suppl_1): IV-6 - IV-19. [Full Text] [PDF] |
||||
![]() |
P. Stenvinkel, U. Diczfalusy, B. Lindholm, and O. Heimburger Phospholipid plasmalogen, a surrogate marker of oxidative stress, is associated with increased cardiovascular mortality in patients on renal replacement therapy Nephrol. Dial. Transplant., April 1, 2004; 19(4): 972 - 976. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Li, V. Williams, L. Liu, H. Chen, T. Sawamura, F. Romeo, and J. L. Mehta Expression of lectin-like oxidized low-density lipoprotein receptors during ischemia-reperfusion and its role in determination of apoptosis and left ventricular dysfunction J. Am. Coll. Cardiol., March 19, 2003; 41(6): 1048 - 1055. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-L. Cracowski, F. Stanke-Labesque, G. Bessard, H. Tsutsui, T. Ide, A. Takeshita, and N. Ohashi Physiological Variations of Isoprostanes: A Step Forward? * Physiological Variations of Isoprostanes: A Step Forward? Response to Letter to the Editor Arterioscler. Thromb. Vasc. Biol., July 1, 2002; 22(7): 1239 - 1241. [Full Text] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | SUBSCRIPTIONS | CURRENT ISSUE | PAST ISSUES | CARDIOSOURCE | SEARCH | HELP | FEEDBACK |