© 2002 European Society of Cardiology
Hypoxia, angiotensin-II, and norepinephrine mediated apoptosis is stimulus specific in canine failed cardiomyocytes: a role for p38 MAPK, Fas-L and cyclin D1
Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart and Vascular Institute Detroit, MI 48202, USA
* Corresponding author. Cardiovascular Research, Henry Ford Hospital, 2799 West Grand Boulevard, Detroit, MI 48202, USA. Tel.: +1-313-916-7360; fax: +1-313-916-3001 E-mail address: hsabbah1{at}hfhs.org
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Abstract |
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 Top Abstract 1. Introduction2. Materials and methods3. Results4. Discussion5. Study limitations6. ConclusionReferences |
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Background: Apoptosis may contribute to the myocardial dysfunction associated with heart failure (HF). Activation of the p38 MAPK cascade can induce apoptosis in non-cardiac cells through increased expression of Fas-L, or through decreased expression of cyclin D1.
Aims: We tested the hypothesis that hypoxia (HX), angiotensin-II (A-II) and norepinephrine (NEPI) can mediate apoptosis by activating p38 MAPK, and thus initiating stimulus specific changes in Fas-L and cyclin D1 expression in failing cardiomyocytes.
Methods and results: Cardiomyocytes isolated from ten dogs with HF induced by coronary microembolizations were subjected to HX or A-II or NEPI with and without a p38 MAPK inhibitor (SB 203580). TUNEL staining for DNA fragmentation and Western blots for p38 MAPK, Fas-L and cyclin D1 detection were performed. HX-induced apoptosis was associated with increased Fas-L expression, A-II-induced apoptosis was associated with increased Fas-L and decreased cyclin D1 expression, and NEPI-induced apoptosis was associated with decreased cyclin D1 expression. Inhibition of p38 MAPK activity attenuated stress-induced apoptosis in all experiments and reversed changes in Fas-L and cyclin D1 expression.
Conclusions: HX, A-II and NEPI mediate apoptosis in failing cardiomyocytes via different effects on Fas-L and cyclin D1 expression. Inhibition of p38 MAPK reversed these effects, suggesting that apoptosis induced by HX, A-II and NEPI involves activation of p38 MAPK upstream from Fas-L and cyclin D1.
Key Words: Heart failure • p38 MAPK • Apoptosis • Fas-L • Cyclin D1
Received April 2, 2002; Revised July 9, 2002; Accepted September 17, 2002
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1. Introduction |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. Study limitations6. ConclusionReferences |
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Progressive worsening of left ventricular (LV) function is a characteristic feature of heart failure (HF). The cause of hemodynamic deterioration is not known but has been attributed, in part, to the ongoing loss of viable cardiac myocytes. Studies performed in animal models of experimentally induced HF and with end-stage, failed, explanted human hearts have suggested that apoptosis may contribute to the ongoing cardiomyocyte loss associated with HF [1,2]. Several maladaptations known to occur in HF have been proposed as triggers of apoptosis, including enhanced formation of angiotensin-II (A-II) and norepinephrine (NEPI), and sustained cardiomyocyte hypoxia (HX). Knowledge regarding the cascade of events leading to apoptosis in failing cardiomyocytes in response to these factors is important in understanding the mechanisms of cardiac myocyte loss in HF.
The pathways that mediate apoptosis appear to be both cell and stimulus specific. The response of normal cardiomyocytes to a stress stimulus, for instance, may differ from that of other cell types. p53, for instance, mediates stress-induced apoptosis in MCF7 breast cancer cells [3], while HX-induced apoptosis in cardiomyocytes occurs independent of p53 activation [4]. Alternatively, stretch-induced release of A-II in neonatal cardiomyocytes triggers apoptosis by activating p53 [5]. The biochemical changes that cardiomyocytes undergo during the course of evolving HF may also alter the sequence of events leading to apoptosis. To date, observations aimed at addressing the mechanisms that mediate cardiomyocyte apoptosis have been made using isolated normal neonatal or adult cardiomyocytes. The mechanisms by which stress stimuli induce apoptosis in failed adult cardiomyocytes remains unknown.
The p38 MAPK cascade has been shown to participate in the induction of apoptosis in various cell types, including normal cardiomyocytes [6]. Activation of the p38 MAPK cascade increases Fas-L [7] and decreases cyclin D1 expression [8], two events that can trigger apoptosis [9,10]. Currently, there are no data regarding the relationship between p38 MAPK, Fas-L and cyclin D1 in stress-induced apoptosis in failing cardiomyocytes. In this study, we examined the effects of HX, A-II and NEPI, prevalent physiological stressors in HF, on apoptosis in cardiomyocytes isolated from failing dog hearts and examined the association between p38 MAPK activation, and Fas-L and cyclin D1 expression in this setting.
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2. Materials and methods |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. Study limitations6. ConclusionReferences |
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2.1. The animal model
The canine model of chronic HF used in this study was previously described in detail [11]. In this preparation, chronic HF is produced by multiple sequential intracoronary embolizations with polystyrene latex microspheres (70–102 µm in diameter), which leads to loss of viable myocardium and a decrease in LV ejection fraction [11]. In the present study, ten healthy mongrel dogs, weighing between 16 and 25 kg, underwent coronary microembolizations to produce HF. Embolizations were performed 1–3 weeks apart and were discontinued when LV ejection fraction was 30–40%. All microembolizations were performed during cardiac catheterization under general anesthesia and sterile conditions. The anesthesia regimen used consisted of a combination of an intravenous injection of oxymorphone (0.22 mg/kg), diazepam (0.17 mg/kg), and sodium pentobarbital (150–250 mg to effect). Dogs were subsequently maintained for a period of 3 months after the last coronary microembolization. The study was approved by the institution Care of Experimental Animal Committee and conformed to the Position of the American Heart Association on Research Animal Use and the guiding principles of the American Physiological Society.
2.2. Angiographic measurements
Left ventriculograms were performed in all dogs 3 months after the last coronary microembolization and just prior to sacrifice to assess LV function based on LV ejection fraction as previously described [11]. At the end of the time when ventriculograms were performed, LV ejection fraction was 29±1%.
2.3. Isolation of cardiomyocytes
After 3 months of follow-up, and while under general anesthesia, the dog's chest was opened and the heart was rapidly removed and placed in ice cold oxygenated Abbott's cardioplegic solution (Abbott Laboratories, Chicago, IL) containing 15 mEq of potassium. Cardiomyocytes were isolated from the LV free wall as previously described [12]. Approximately 20 g of LV tissue were used to isolate myocytes. The yield of rod-shaped quiescent myocytes from failed hearts that excluded trypan blue was >85%. Thin transmural slices, approximately 1-mm thick, were cut from the tissue blocks and immediately placed in saturated 95% O2, 5% CO2 normal Tyrode's solution (4 mM K+, 2 mM Ca2+) at 37 °C. The tissue was then rinsed twice in calcium free HEPES solution (115 mM NaCl, 5 mM KCl, 35 mM sucrose, 10 mM glucose, 10 mM HEPES, and 4 mM taurine, pH 6.95) to remove any residual blood. Tissue slices were then placed in a 100 ml polyethylene beaker containing 50 ml of HEPES solution with 15 µM Ca2+ and the beaker placed in a 36 °C water bath. A Harvard respirator was then connected to the needle end of a 20 ml plastic syringe (without plunger) with the wide end placed in the polyethylene beaker such that the solution is drawn into the syringe with each pump cycle. The respirator was adjusted to permit the HEPES solution plus tissue to be drawn up to 7/8 of the syringe height, at a rate of 25 cycles/min, a procedure referred to as trituration. A stream of O2 (100%) was applied continuously to the beaker during the isolation procedure. The tissue was then triturated for 30 min with HEPES solution containing 0.05% collagenase (type 2, Worthington, Freehold, NJ), 0.025% collagenase (type 1, Worthington, Freehold, NJ), and 0.13 mg/ml protease (type XIV, Sigma). Further triturations were performed without protease. The dissociated dead cells and debris from the first four triturations were discarded and the cardiomyocytes from the fifth through the ninth trituration were combined. The combined suspension was collected and centrifuged at 500xg for 3 min. The pellet was resuspended in 50 ml HEPES solution and the resulting suspension placed in 2x 50 ml polypropylene tubes and allowed to stand for 5 min to allow the rod-shaped cardiomyocytes to settle by gravity. To ensure that cardiomyocytes are calcium tolerant, the settled myocytes were re-suspended each time in 50 ml HEPES buffer with increasing Ca2+ concentration of 50, 100, 200, 400, 800 and 1000 µM. The myocytes were allowed 30 min to settle by gravity after each calcium buffer change. Finally, the settled cardiomyocytes were resuspended in HEPES buffer containing 1 mM Ca2+.
2.4. Incubation of isolated cardiomyocytes
Cardiomyocytes were plated in petri dishes (Corning, NY) coated with 0.5 µg/cm2 of laminin (Sigma Chemical Co., St. Louis, MO) at a density of 2x104 cells/cm2. Before plating, cardiomyocytes were washed free of BSA and resuspended in Medium 199 with Earle's salts (Sigma Chemical Co.) containing 25 mM N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid (HEPES) and supplemented with L-glutamine (1.3 mM), L-carnitine (2 mM), creatine (5 mM), taurine (5 mM), insulin (0.1 µM), triiodothyronine (0.1 nM), pyruvate (2.5 mM), NaHCO3, 1.0 mM Ca2+, penicillin (100 U/ml), streptomycin (50 µg/ml) and transferrin (10 µg/ml). The serum free medium was changed 30 min after plating to remove myocytes that did not attach to the dish, thus improving the yield to near 100%. In all instances described below, cultures were incubated at 37 °C, the medium initial pH was 7.2.
2.5. Experimental protocol
2.5.1. Control
Cardiomyocytes incubated for 3 h under normoxic conditions (95% air/5% CO2) at 37 °C were used as a control for HX, A-II and NEPI experiments.
2.5.2. Hypoxia exposed cells
Hypoxic conditions were produced by placing the dishes containing the isolated cardiomyocytes in an air-tight incubator at 37 °C for 3 h where room air was replaced by 95% N2/5% CO2. Cells were exposed to HX alone or incubated with 10 µM of the p38 MAPK inhibitor, SB 203580 (Calbiochem Co., La Jolla, CA).
2.5.3. Angiotensin-II exposed cells
Cells were incubated with either 0.5 µM A-II alone (Sigma Chemical Co.), A-II+0.5 µM eprosartan (an AT1 receptor antagonist) (Smith Kline Beecham, King of Prussia, PA) or A-II+SB 203580 (10 µM) under normoxic conditions for 3 h at 37 °C. Cells were incubated with eprosartan or SB 203580 10 min before A-II was added.
2.5.4. Norepinephrine exposed cells
Cells were incubated with either 10 µM NEPI alone, NEPI+2 µM propranolol (a β-adrenergic receptor antagonist) (Golgline, Ft. Lauderdale, FL), or NEPI+SB 203580 (10 µM) under normoxic conditions for 3 h at 37 °C. Cells were incubated with propranolol or SB 203580 10 min before NEPI was added.
At the end of each experiment, the pH of the medium was measured as was cell viability based on the percent of rod-shaped cross-striated cells that exclude trypan blue. Only cell preparations that had 
3% change in cell viability and 0.2 in pH change were studied. Aliquots of cells were placed in cryostat micro tubes and flash frozen in liquid nitrogen and stored at –70 °C until ready to use.
2.6. Western blotting
Western blots were performed as previously described [13] with some modifications. Briefly, approximately 100 mg of frozen cardiomyocytes were homogenized in a lysis buffer (10 mM Tris base pH 7.5; 10 mM EDTA, 0.4% deoxycholate, 1% NP-40, 0.1% SDS) containing protease inhibitor (PMSF 1 µl/100 µl of lysis buffer). The homogenate was centrifuged and the supernatant saved for Western blotting. Approximately 10–15 µl of the supernatant containing 55 µg of protein was subjected to electrophoresis through a 4–20% Tris–Glycine polyacrylamide gel (Bio-Rad, Hercules, CA). The separated proteins were transferred to a nitrocellulose membrane (Immuno-Lite Assay Kit, Bio-Rad). The membrane was then incubated with primary antibody and then with secondary antibody for 2 h each. The antibody bound antigen was identified by chemiluminescence followed by autoradiography. The density of bands corresponding to the proteins of interest was measured using a desktop high performance imaging densitometer (GS-670, Bio-Rad). The unit of densitometric measurement was ODxmm2 where OD is optical density. Polyclonal rabbit anti-p38 MAPK, anti-Fas-L, and anti-cyclin D1 antibodies were obtained from Santa Cruz Biotechnology, Inc (Santa Cruz, CA).
2.7. Identification of nuclear DNA fragmentation in isolated cardiomyocytes
To detect nuclear DNA fragmentation in isolated cardiomyocytes, DNA nick-end labeling (TUNEL) was performed as described by Gavrieli et al. [14] using a kit provided by Promega Corp. (Madison, WI). After removing medium, cardiomyocytes were air dried, fixed with 4% methanol-free formaldehyde solution in PBS for 30 min at 4 °C and washed twice with PBS. The cells were then covered with incubation buffer containing terminal deoxynucleotidyl transferase and fluorescein-12-dUTP. The reaction was terminated with 2x SSC. To identify nuclei, counterstaining was performed with propidium iodide. The samples were analyzed under a fluorescent microscope, nDNAf events were visualized as yellow–green under fluorescein light (Nikon DM510 filter) and cell nuclei were seen as red under rhodamine light (Nikon DM580 filter) (Fig. 1). The percentage of positively labeled nuclei in isolated cardiomyocytes was determined visually in 80 light microscopic fields (magnification x40) in each petri dish. The positively TUNEL stained cardiomyocytes exhibit apoptotic blebbing seen as a bulging of the membrane (Fig. 1D–F).
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2.8. Data analysis
Comparisons of the hemodynamic and angiographic measures of LV function were made between values obtained after the last embolization and 3 months after the last embolization. For these comparisons, a Student's paired t-test was used and a probability of 0.05 or less was considered significant. A one-way analysis of variance was used to determine whether differences exist in expression of proteins or in incidence of DNA fragmentation events studied between untreated failing cardiomyocytes and cardiomyocytes exposed to HX, A-II, NEPI, SB 203580, eprosartan, and propranolol. For this test, significance was set at
=0.05. The results are presented as mean±S.E.M. |
3. Results |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. Study limitations6. ConclusionReferences |
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3.1. Exposure of failing cardiomyocytes to HX
Exposure of failing cardiomyocytes to HX increased the incidence of apoptosis by approximately threefold (Fig. 2a). The expression of p38 MAPK and Fas-L were also significantly increased in hypoxic cells (Fig. 2b and c), while the expression of cyclin D1 was not affected (Fig. 2d). Inhibition of p38 MAPK activity with SB 203580 significantly reduced apoptosis compared with cells exposed to HX alone. SB 203580 also decreased Fas-L expression to near control levels, without influencing cyclin D1 and p38 MAPK expression (Fig. 2).
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3.2. Exposure of failing cardiomyocytes to A-II
Exposure of failing cardiomyocytes to A-II approximately doubled the incidence of apoptosis compared with control (Fig. 3a). A-II also significantly increased the expression of p38 MAPK and Fas-L, and significantly decreased the expression of cyclin D1 (Fig. 3b–d). SB 203580 prevented A-II induced apoptosis (Fig. 3a). Inhibition of p38 MAPK activity did not affect p38 MAPK expression compared to cells treated with A-II alone (Fig. 3b). SB 203580 reversed the effect of A-II on Fas-L and cyclin D1 expression (Fig. 3c and d). Treatment with eprosartan also prevented A-II-induced apoptosis and p38 MAPK overexpression but had the same effects on Fas-L and cyclin D1 expression as SB 203580 (Fig. 3).
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3.3. Exposure of failing cardiomyocytes to NEPI
Exposure of failing cardiomyocytes to NEPI nearly doubled the incidence of apoptosis compared to control (Fig. 4a). NEPI also significantly increased p38 MAPK expression and nearly abolished cyclin D1 expression (Fig. 4b and d), while having no effect on Fas-L expression (Fig. 4c). Treatment with SB 203580 partially protected failing cardiomyocytes from NEPI-induced apoptosis (Fig. 4a). Inhibition of p38 MAPK activity did not change p38 MAPK or Fas-L expression compared with cells treated with NEPI alone (Fig. 4b and c), however, it did reverse the depression of cyclin D1 expression caused by NEPI (Fig. 4d). Treatment with propranolol attenuated NEPI induced cardiomyocyte apoptosis, reduced p38 MAPK expression and increased cyclin D1 but did not alter Fas-L expression compared with cells treated with NEPI alone (Fig. 4).
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4. Discussion |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. Study limitations6. ConclusionReferences |
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The present study demonstrates that exposure of failing cardiac myocytes to either HX, A-II, or NEPI significantly increases the incidence of apoptosis. These three factors are believed to contribute to the progression of LV dysfunction and remodeling that is characteristic of the HF state [15,16]. We and others have previously postulated that ongoing cell death through apoptosis may be one mechanism that drives the progression of LV dysfunction and remodeling in HF. Even though HX, A-II, and NEPI each ultimately increased the incidence of apoptosis in failing cardiomyocytes, the cascade through which apoptosis was induced was different for each of the three conditions.
Previous studies demonstrated that apoptosis in normal neonatal cardiomyocytes can be initiated by prolonged (>12 h) severe HX [17]. Subsequently, Webster et al. reported that severe HX alone does not cause apoptosis in cultured normal neonatal cardiomyocytes unless there is a decrease in extracellular pH [4]. We observed that only 3 h of HX stimulated a threefold increase in the incidence of apoptosis in adult failing cardiomyocytes, in the absence of any changes in extracellular pH. While not a primary purpose of the present work, our results nonetheless suggest that failing myocytes may be more susceptible to the damaging effects of HX.
Circulating levels of A-II and NEPI are also enhanced in HF. While initially these mechanisms are compensatory in nature, over time they can lead to worsening of LV function and progressive LV chamber remodeling. Earlier studies demonstrated that A-II stimulates a fivefold increase of apoptosis in normal adult cardiomyocytes after 24 h of exposure [18]. Leri et al. [19] also showed that A-II triggers apoptosis in the postinfarcted rat heart and that AT1 receptor blockade inhibits stretch-activated apoptosis in failing cardiomyocytes. In our study, short-term (3 h) exposure to A-II doubled the incidence of apoptosis in failing cardiomyocytes. Blockade of A-II receptors with the AT1 receptor antagonist, eprosartan, prevented A-II mediated apoptosis. Even though downregulation of the AT1 receptor subtype has been reported in HF [20], failing adult cardiomyocytes appear to remain susceptible to A-II mediated apoptosis. NEPI has also been shown to cause apoptosis in normal adult [21–23] and neonatal cardiomyocytes [24]. The present work demonstrates that adult failing cardiomyocytes are also susceptible to the pro-apoptotic effects of NEPI. Attenuation of apoptosis with the β-receptor antagonist, propranolol, verifies the role of NEPI in our model. Again, though β-adrenoceptors are downregulated in HF, this did not appear to attenuate the effect of NEPI on failing cardiomyocytes in our study.
Despite the differences in Fas-L and cyclin D1 expression between the groups, all treatments resulted in an increase in p38 MAPK expression, which correlated with an increase in apoptotic events. In addition, inhibition of p38 MAPK activity with SB 203580 attenuated the apoptosis triggered by exposure to HX, A-II and NEPI and prevented their effects on Fas-L and cyclin D1 expression. These results suggest that p38 MAPK is activated upstream from Fas-L and cyclin D1 regardless of the stimuli used in these experiments.
One pathway by which p38 MAPK has been shown to mediate apoptosis is through decreased expression of cyclin D1. Cyclin D1 acts to stop progression of the cell cycle in the G-phase. It has been demonstrated in PC12 cells that HX-induced p38 MAPK activation decreases the expression of cyclin D1 and, that this effect can be partially blocked by SB 203580 [8]. The present study shows that A-II and NEPI induced apoptosis are associated with decreased expression of cyclin D1, and that inhibition of p38 MAPK activity prevented both cardiomyocyte apoptosis and downregulation of the expression of cyclin D1. Suppression of cyclin D1 expression may also account for the pro-apoptotic effects of NEPI on failing cardiomyocytes. In cardiomyocytes exposed to A-II, the increase in Fas-L expression in combination with the decrease in cyclin D1 expression may both have led to apoptosis. HX did not alter expression of cyclin D1 and led to Fas-L upregulation. Inhibition of p38 MAPK activity in cells exposed to HX and A-II attenuated both cardiomyocyte apoptosis and Fas-L upregulation. Even though HX, A-II and NEPI all appear to operate through p38 MAPK activation, their downstream effects on Fas-L and cyclin D1 expression vary markedly. This information may be useful toward the design of specific anti-apoptotic compounds that may be useful as adjunctive therapy for the treatment of HF.
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5. Study limitations |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. Study limitations6. ConclusionReferences |
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One of the limitations of the present study is the lack of measurement of p38 MAPK activity. This was due to the lack of availability of a canine-specific phospho-antibody. Another discrepancy was that the percent of TUNEL positive cardiomyocytes in the control group was unexpectedly high (
5%) compared to approximately 0.01% of TUNEL positive cardiomyocytes detected in failed myocardium of experimental animals [1] and humans [2] in situ. This, however, is in close agreement with other publications in which isolated cardiomyocytes were used [23]. The isolation procedure itself may stimulate apoptosis. Since this study used the same procedure to isolate the cardiomyocytes used in all groups, it is not a factor when comparing the results of our work. |
6. Conclusion |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. Study limitations6. ConclusionReferences |
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Finally, while the observations made in this study strongly suggest that HX, A-II and NEPI can mediate apoptosis of failing cardiomyocytes through activation of different pathways, a direct causal relationship remains to be elucidated.
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Acknowledgements |
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Supported by a grant from the National Heart, Lung, and Blood Institute HL-49090-07.
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References |
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TopAbstract1. Introduction2. Materials and methods3. Results4. Discussion5. Study limitations6. ConclusionReferences |
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- Sharov V.G., Sabbah H.N., Shimoyama H., Goussev A., Lesch M., Goldstein S. Evidence of cardiocyte apoptosis in myocardium of dogs with chronic heart failure. Am J Pathol (1996) 148:141–149.[Abstract]
- Narula J., Haider N., Virmani R., et al. Apoptosis in myocytes in end-stage heart failure. N Engl J Med (1996) 335:1182–1189.
[Abstract/Free Full Text] - Fuchs S.Y., Adler V., Pincus M.R., Ronai Z. MEKK1/JNK signaling stabilizes and activates p53. Proc Natl Acad Sci USA (1998) 95:10541–10546.
[Abstract/Free Full Text] - Webster K.A., Discher D.J., Kaiser S., Hernandez O., Sato B., Bishopric N.H. Hypoxia-activated apoptosis of myocytes requires reoxygenation or a pH shift and is independent of p53. J Clin Invest (1999) 104:239–252.[Web of Science][Medline]
- 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 ratio in the cell. J Clin Invest (1998) 101:1326–1342.[Web of Science][Medline]
- Wang Y., Huang S., Sah V.P., et al. Cardiac muscle cell hypertrophy and apoptosis induced by distinct members of the p38 mitogen-activated protein kinase family. J Biol Chem (1998) 273:2161–2168.
[Abstract/Free Full Text] - Hsu S.C., Gavrilin M.A., Tsai M.H., Jiahuai H., Lai M.Z. p38 mitogen-activated protein kinase is involved in Fas Ligand expression. J Biol Chem (1999) 274:25769–25776.
[Abstract/Free Full Text] - Conrad P.W., Rust R.T., Han J., Millhorn D.E., Beitner-Johnson D. Selective activation of p38 and p38β by hypoxia. Role in regulation of cyclin D1 by hypoxia in PC12 cells. J Cell Biol (1999) 274:23570–23578.
- Kawahara A., Enari M., Talanian R.V., Wong W.W., Nagata S. Fas-induced DNA fragmentation and proteolysis of nuclear proteins. Genes Cells (1998) 3:297–306.[Abstract]
- Hiyama H., Reeves S.A. Role for cyclin D1 in UVS-induced and p53-mediated apoptosis. Cell Death Differ (1999) 6:565–569.[CrossRef][Web of Science][Medline]
- Sabbah H.N., Stein P.D., Kono T., et al. A canine model of chronic heart failure produced by multiple sequential intracoronary microembolization. Am J Physiol (1991) 260:H1379–H1384.[Web of Science][Medline]
- Lue W.M., Boyden P.A. Abnormal electrical properties of myocytes from chronically infarcted canine heart. Alterations in Vmax and the transient outward current. Circulation (1992) 85:1175–1188.
[Abstract/Free Full Text] - Symington J., Green M., Brackman K. Immunoautoradiographic detection of proteins after electrophoretic transfer from gels to diazo-paper: analysis of adenovirus encoded proteins. Proc Natl Acad Sci USA (1981) 78:177–181.
[Abstract/Free Full Text] - Gavrieli Y., Sherman Y., Ben-Sasson S.A. Identification of programmed cell death in situ via specific labeling of nuclear DNA fragmentation. J Cell Biol (1992) 119:493–501.
[Abstract/Free Full Text] - Sabbah H.S., Sharov V.G., Goldstein S. Programmed cell death in the progression of heart failure. Ann Med (1998) 30:33–38.[Medline]
- Sabbah H.N., Sharov V.G., Goldstein S. Remodeling of the cardiac interstitium in the progression of heart failure. J Clin Basic Cardiol (1999) 2:113–116.
- 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]
- Kajstura J., Cigola E., Malhotra A., et al. Angiotensin II induces apoptosis of adult ventricular myocytes in vitro. J Mol Cell Cardiol (1997) 29:859–870.[CrossRef][Web of Science][Medline]
- Leri A., Liu Y., Li B., et al. Up-regulation of AT(1) and AT(2) receptors in postinfarcted hypertrophied myocytes and stretch-mediated apoptotic cell death. Am J Pathol (2000) 156:1663–1672.
[Abstract/Free Full Text] - Asano K., Dutcher D.L., Port D.J., et al. Selective downregulation of the angiotensin II AT1-receptor subtype in failing human ventricular myocardium. Circulation (1997) 95:1193–1200.
[Abstract/Free Full Text] - Zaugg M., Xu W., Lucchinetti E., Shafiq S.A., Jamali N.Z., Siddiqui M.A.Q. [beta]-Adrenergic receptor subtypes differentially affect apoptosis in adult rat ventricular myocytes. Circulation (2000) 102:344–350.
[Abstract/Free Full Text] - Zaugg M., Jamali N., Lucchinetti E., Shafiq S.A., Siddiqui M.A.Q. Norepinephrine-induced apoptosis is inhibited in adult rat ventricular myocytes exposed to volatile anesthetics. Anesthesiology (2000) 93:209–218.[CrossRef][Web of Science][Medline]
- Communal C., Singh K., Pimentel D., Colucci W.S. Norepinephrine stimulates apoptosis in adult rat ventricular myocytes by activation of the beta-adrenergic pathway. Circulation (1998) 98:1329–1334.
[Abstract/Free Full Text] - Shyu K.G., Kuan P., Chang M.L., Wang B.W., Huang F.Y. Effects of norepinephrine on apoptosis in rat neonatal cardiomyocytes. J Formosan Med Assoc (2000) 99:412–418.[Web of Science][Medline]
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