Skip Navigation

European Journal of Heart Failure 2005 7(7):1095-1098; doi:10.1016/j.ejheart.2005.01.015
This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Izgi, C.
Right arrow Articles by Ozkan, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Izgi, C.
Right arrow Articles by Ozkan, M.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2005 European Society of Cardiology

Serum anti-p53 antibodies do not occur in patients with heart failure due to idiopathic dilated and ischemic cardiomyopathies

Cemil Izgi, Cihan Cevik, Nihal Ozdemir, Cihangir Kaymaz and Mehmet Ozkan*

Kosuyolu Heart & Research Hospital Istanbul, Turkey

* Corresponding author. E-mail address: memoozkan{at}superonline.com


   Abstract
Top
 Abstract
1. Introduction
 2. Methods
 3. Results
 4. Discussion
 References
 
Background: P53 is a key protein which controls cell cycle arrest and apoptosis in response to DNA damage. Auto-antibodies against p53 have been detected in some cancer patients and also in patients with autoimmune diseases. In these patients, the main cause of anti-p53 antibody occurrence was considered to be increased intracellular p53 protein in cancer cells and autoreactive lymphocytes, respectively. Intracellular p53 also increases with cardiomyocyte apoptosis during heart failure and autoreactive lymphocytes play a role in the course of idiopathic dilated cardiomyopathy (IDC) and ischemic cardiomyopathy (ICM). Based on these observations, we hypothesized that anti-p53 antibody response may also occur in patients with heart failure due to ICM and IDC.

Aim: The aim of this study was to evaluate anti-p53 antibodies in the serum of patients with heart failure due to IDC and ICM.

Methods: 70 eligible patients with heart failure and severe left ventricular systolic dysfunction (mean fractional shortening 12.03±3.93%) were included in the study. The aetiology of heart failure was IDC in 26 patients and ICM in 44 patients, according to the angiographic and echocardiographic findings.

Results: Anti-p53 antibodies were not detected in any of the patients.

Conclusion: Anti-p53 antibodies do not occur in patients with heart failure due to IDC and ICM, possible explanations are discussed in the text.

Key Words: p53 • Anti-p53 • Heart failure • Autoimmunity • Autoantibodies

Received May 23, 2004; Revised September 21, 2004; Accepted January 27, 2005


   1. Introduction
Top
 Abstract
 1. Introduction
2. Methods
 3. Results
 4. Discussion
 References
 
P53 is a key protein that triggers cell cycle arrest or apoptosis in response to DNA damage by acting as a transcription factor for the genes involved in these processes. Intracellular levels of p53 protein increase dramatically following a DNA damaging insult such as oxidative stress or hypoxia and this occurs due to increased stability of the p53 protein [1].

Auto-antibodies against p53 protein were first shown in patients with cancer [2,3]. In these patients, the presence of anti-p53 antibodies mostly correlated with intracellular p53 accumulation, due to increased stability of mutant p53 protein, as demonstrated by immunohistochemical staining of tissue samples [3]. Subsequently, it has been shown that antibody response is induced by epitopes located in the carboxy and amino terminals of the p53 protein outside the central mutational hot spot region [4]. Accordingly, accumulation of the p53 protein–mutant or native–in the cell has been considered to be the main cause of anti-p53 antibody production [3,4].

It has been suggested that apoptotic cardiomyocyte loss is an important pathogenic component during the onset and progression of heart failure [5,6]. Although p53 protein is normally undetectable in healthy adult cardiomyocytes [7], increased intracellular levels of p53 have been shown following cardiomyocyte apoptosis in various types of heart failure [8–11]. In a study by Long et al., rat myocytes exposed to hypoxia underwent apoptosis, which was accompanied by an intracellular increase in p53 protein levels [9]. In this study, overexpression of p53 in normoxic myocytes was sufficient to induce apoptosis. Increased intracellular p53 levels accompanying cardiomyocyte apoptosis have also been shown in the extracted hearts of transplanted patients with heart failure due to idiopathic dilated cardiomyopathy (IDC) [10]. Angiotensin II, one of the most important mediators of heart failure, induces cardiomyocyte apoptosis coupled with increased intracellular p53 [11]. Whether an anti-p53 response accompanies this intracellular increase in p53 during cardiomyocyte apoptosis in heart failure patients is unknown.

In addition to cancer patients, anti-p53 antibodies have also been detected in some patients with autoimmune diseases such as systemic lupus erythematosus [12,13], rheumatoid arthritis [13] and type 1 diabetes [14]. In these patients, it has been hypothesized that anti-p53 antibodies reflect overexpression of p53 in abnormally proliferating autoreactive lymphocytes [13]. Autoimmune mechanisms are involved in the pathogenesis of IDC; autoantibodies and autoreactive lymphocytes have been detected in these patients [15–17]. Neurohumorally activated autoreactive lymphocytes are also thought to mediate the onset and progression of heart failure following myocardial infarction [18].

Two aspects of these previous studies, increased intracellular p53 accompanying cardiomyocyte apoptosis during the onset and progression of heart failure and the proposed autoimmune nature of IDC and ischemic cardiomyopathy (ICM) accompanied by the occurrence of autoantibodies and autoreactive lymphocytes in these patients, have led to the hypothesis that anti-p53 antibodies may also occur in patients with heart failure due to IDC and ICM. Thus, the primary aim of this study was to test for anti-p53 antibodies in patients with heart failure due to ICM and IDC. If anti-p53 antibodies were present, we also aimed to determine possible clinical and echocardiographic correlates of anti-p53 positivity.


   2. Methods
Top
 Abstract
 1. Introduction
 2. Methods
3. Results
 4. Discussion
 References
 
73 consecutive patients presenting with heart failure symptoms and echocardiographically proven left ventricular systolic dysfunction were recruited. Since anti-p53 antibody has been consistently shown to be absent in the serum of healthy subjects [3], 26 healthy subjects were included in the study as negative controls. Three patients with concomitant systemic diseases (two patients with a history of cancer and one with active rheumatoid arthritis) were later excluded from the study group. Thus, the study population finally included 70 patients and 26 controls. All patients gave informed consent to participate and the study was approved by the local ethics committee. The investigation conformed with the principles outlined in the Declaration of Helsinki.

Echocardiographic examination was performed in all patients (GE, Vivid 5, Oslo, Norway). None of the patients had significant valvular lesion as the cause of heart failure. Fractional shortening (%) was calculated from the parasternal long-axis left ventricular end-systolic (LVIDs) and end-diastolic (LVIDd) internal dimensions as [(LVIDd–LVIDs)/LVIDd]x100%. Ejection fraction was calculated according to the Simpson method. Fractional shortening (≤25%) was accepted as evidence of left ventricular systolic dysfunction. Coronary angiography was performed in all patients in standard views.

Blood samples were collected from each subject and centrifuged to obtain serum samples, which were stored at –20C until assay. For anti-p53 antibody detection, a highly specific anti-p53 ELISA kit (Euroimmun AG, Leubeck; Germany) was used according to the manufacturer's instructions. This is a solid phase ELISA system that uses prokaryotically expressed native p53 as the antigen; the diagnostic accuracy of this system for anti-p53 antibody detection has been well validated previously [19].

The etiology of heart failure was defined as ICM if the patient had a history of documented myocardial infarction (by ECG or hospital records) and/or ≥50% luminal stenosis in any of the major coronary arteries. In the absence of either of these criteria, the etiology in the remaining patients was defined as IDC.

Quantitative data are expressed as means±standard deviation.


   3. Results
Top
 Abstract
 1. Introduction
 2. Methods
 3. Results
4. Discussion
 References
 
Clinical characteristics, echocardiographic findings and the anti-p53 antibody status of the 70 patients are summarized in Table 1. The etiology of heart failure was diagnosed as ICM in 44 patients and IDC in 26 patients. All patients had severe left ventricular dysfunction (mean fractional shortening: 12.03±3.93). Serum anti-p53 antibodies were not detected in any of these patients. Similarly, anti-p53 antibodies were not detected in any of the control subjects.


View this table:
[in this window]
[in a new window]

  		Table 1 Baseline characteristics and anti-p53 status of the patients

 

   4. Discussion
Top
 Abstract
 1. Introduction
 2. Methods
 3. Results
 4. Discussion
References
 
Serologic analysis for anti-p53 antibody detection is a simple assay that indicates immune response to increased intracellular p53 protein (3). This study has shown for the first time that anti-p53 antibodies do not occur in patients with heart failure due to ICM or IDC.

The absence of anti-p53 antibodies in heart failure patients can be explained in several ways. First, although an increase in intracellular level of p53 protein is a prerequisite for anti-p53 antibody formation, the critical level required, the duration of the increase and the way in which p53 is presented to the immune system are not known [4]. Accordingly, although intracellular p53 may be increased during cardiomyocyte apoptosis and autoimmunity during the course of heart failure, levels may not have reached the critical level required for extracellular release and antibody formation. Secondly, the lack of anti-p53 antibodies in our patient group, who were all of Turkish race, may be due to ethnic or racial differences in the immune response to p53. Racial differences in anti-p53 response have been shown previously. Anti-p53 antibodies have been detected in a variable proportion of systemic lupus erythematosus and rheumatoid arthritis patients from western countries but were not detected in Japanese [20] and Chinese [21] patients. This kind of ethnic or racial variability in autoantibody response has also been shown for other autoantibodies in IDC patients [17].

Autoantibodies are present in only 30–40% of IDC patients and their titers and positivity tend to decrease with disease progression [22]. Although the duration of heart failure symptoms was less than 12 weeks in all of the patients in our study, the total number of IDC patients was relatively low. Thus, testing for anti-p53 antibodies in a larger patient group and even earlier in the disease course may yield some positivity.

Finally, although intracellular p53 has been shown to be increased in heart failure, cardiomyocyte apoptosis may also occur independently and without an increase in the intracellular levels of p53. In fact, Bialik et al. showed that cardiomyocyte apoptosis still occurred in response to hypoxia following coronary occlusion in a p53 knock-out mouse model [23], this is in accordance with the general observation that multiple, and overlapping apoptotic pathways are activated in the ischemic and failing heart [5]. Thus, the prerequisite for anti-p53 antibody formation, increase in intracellular p53, may not have occurred during cardiomyocyte apoptosis in our patients. This possibility could only be excluded by obtaining cardiac biopsy samples from the patients and studying these samples immunohistochemically for p53 accumulation. This was not done in our study due to the invasive nature of the biopsy procedure. Although this appears to be a limitation of our study, evidence from previous studies [8–11] strongly supports the view that, when cardiomyocytes are not knockout, intracellular levels of p53 increase with cardiomyocyte apoptosis in heart failure patients.

In conclusion, the results of this study suggest that, if intracellular p53 levels increase with cardiomyocyte apoptosis and autoimmunity, this may not be associated with the presence of anti-p53 antibodies in patients with heart failure due to ischemic and dilated cardiomyopathies. The presence of anti-p53 antibodies requires further investigation in a larger group of heart failure patients with different ethnic origins and with immunohistochemical studies of cardiac biopsy samples for p53 accumulation.


   References
Top
 Abstract
 1. Introduction
 2. Methods
 3. Results
 4. Discussion
 References
 

  1. Kastan M.B., Onyekwere O., Sidransky D., Vogelstein B., Craig R.W. Participation of p53 protein in the cellular response to DNA damage. Cancer Res (1991) 51:6304–6311.[Abstract/Free Full Text]
  2. Angelopoulou K., Diamandis E.P., Sutherland D.J.A., Kellen J.A., Bunting P.S. Prevalence of serum antibodies against the p53 tumor suppressor gene protein in various cancers. Int J Cancer (1994) 58:480–487.[Web of Science][Medline]
  3. Soussi T., Legros Y., Lubin R., Ory K., Schlichtholz B. Multifactorial analysis of p53 alteration in human cancer: a review. Int J Cancer (1994) 57:1–9.[Web of Science][Medline]
  4. Schlichtholz B., Legros Y., Gillet D., et al. The immune response to p53 in breast cancer patients is directed against immunodominant epitopes unrelated to the mutational hot spot. Cancer Res (1992) 52:6380–6384.[Abstract/Free Full Text]
  5. Bennett R.M. Apoptosis in the cardiovascular system. Heart (2002) 87:480–487.[Free Full Text]
  6. Olivetti G., Maestri R., Cigola E., Corradi D., Quaini F. Does apoptosis play a role in the progression of heart failure? Dialogues Cardiovasc Med (1998) 3:91–94.
  7. Kim K.K., Soonpaa M.H., Daud A.I., Koh G.Y., Kim J.S., Field L.J. Tumor suppressor gene expression during normal and pathologic myocardial growth. J Biol Chem (1994) 269:22607–22613.[Abstract/Free Full Text]
  8. Leri A., Liu Y., Malhotra A., et al. Pacing-induced heart failure in dogs enhances the expression of p53 and p53-dependent genes in ventricular myocytes. Circulation (1998) 97:194–203.[Abstract/Free Full Text]
  9. Long X., Boluyt M.O., Hipolito M.L., et al. P53 and the hypoxia induced apoptosis of cultured neonatal rat cardiac myocytes. J Clin Invest (1997) 99:2635–2643.[Web of Science][Medline]
  10. Song H., Conte J.V., Foster A.H., McLaughkin J.S., Wei C. Increased p53 protein expression in human failing myocardium. J Heart Lung Transplant (1999) 18:744–749.[CrossRef][Web of Science][Medline]
  11. Leri A., Claudio P.P., Li Q., et al. Stretch-mediated release of angiotensin II induces myocyte apoptosis by activating p53 that enhances the local renin-angiotensin system and decreases the Bcl-2-to-Bax protein ratio in the cell. J Clin Invest (1998) 101:1326–1342.[Web of Science][Medline]
  12. Herkel J., Mimran A., Erez N., et al. Autoimmunity to the p53 protein is a feature of systemic lupus erythematosus (SLE) related to anti-DNA antibodies. J Autoimmun (2001) 17:63–69.[CrossRef][Web of Science][Medline]
  13. El-Sayed Z.A., Farag D.H., Eissa S. Tumor suppressor protein p53 and anti-p53 autoantibodies in pediatric rheumatological diseases. Pediatr Allergy Immunol (2003) 14:229–233.[CrossRef][Web of Science][Medline]
  14. Di Cesare E., Previti M., Lombardo F., et al. Serum anti-p53 autoantibodies in patients with type 1 diabetes. Ann Clin Lab Sci (2001) 31:253–258.[Abstract/Free Full Text]
  15. Hjalmarson A., Fu M., Mobini R. Who are the enemies? Inflammation and autoimmune mechanisms. Eur Heart J, Suppl (2002) 4(Suppl. G):G27–G32.[Abstract]
  16. Caforio A.L., Mahon N.J., Tona F., McKenna W.J. Circulating cardiac autoantibodies in dilated cardiomyopathy and myocarditis: pathogenetic and clinical significance. Eur J Heart Fail (2002) 4:411–417.[Abstract/Free Full Text]
  17. Caforio A.L., Bauce B., Boffa G.M., et al. Autoimmunity in myocarditis and dilated cardiomyopathy: cardiac autoantibody frequency and clinical correlates in a patient series from Italy. G Ital Cardiol (1997) 27:106–112.[Medline]
  18. Maisel A., Cesario D., Baird S., Rehman J., Haghighi P., Carter S. Experimental autoimmune myocarditis produced by adoptive transfer of splenocytes after myocardial infarction. Circ Res (1998) 82:458–463.[Abstract/Free Full Text]
  19. Rohayem J., Conrad K., Zimmermann T., Frank K.H. Comparison of the diagnostic accuracy of three commercially available enzyme immunoassays for anti-p53 antibodies. Clin Chem (1999) 45:2014–2016.[Free Full Text]
  20. Kitasato H., Okamoto R., Kawai S. Absence of p53 mutation in Japanese patients with rheumatoid arthritis: comment on the article by Han et al. Arthritis Rheum (2000) 43:469–470.[Web of Science][Medline]
  21. Shiau M.Y., Kuo T.M., Tsay G.J., Chiou H.L., Lee Y.L., Chang Y.H. Absence of anti-p53 antibodies in Chinese patients with rheumatoid arthritis and systemic lupus erythematosus: comment on the concise communication by Kovacs et al. Arthritis Rheum (2002) 46:276–277.[Web of Science][Medline]
  22. Caforio A.L., Goldman J.H., Baig M.K., et al. Cardiac autoantibodies in dilated cardiomyopathy become undetectable with disease progression. Heart (1997) 77:62–67.[Abstract/Free Full Text]
  23. Bialik S., Geenen D.L., Sasson I.E., et al. Myocyte apoptosis during acute myocardial infarction in the mouse localizes to hypoxic regions but occurs independently of p53. J Clin Invest (1997) 100:1363–1372.[Web of Science][Medline]

Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?



This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Izgi, C.
Right arrow Articles by Ozkan, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Izgi, C.
Right arrow Articles by Ozkan, M.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?