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(Hypertension. 1999;33:1348-1352.)
© 1999 American Heart Association, Inc.
Scientific Contributions |
p53-Mediated Upregulation of BAX Gene Transcription Is Not Involved in Bax-
Protein Overexpression in the Left Ventricle of Spontaneously Hypertensive Rats
From the Vascular Pathophysiology Unit, School of Medicine, University of Navarra, Pamplona (M.A.F., G.Z., S.R., E.D., F.J.B., A.F., J.D.), and Department of Medicine, School of Medicine, University of Zaragoza, Zaragoza (J.D.), Spain.
Correspondence and reprint requests to Dr Javier Díez, Unidad de Fisiopatología Vascular, Facultad de Medicina, C/Irunlarrea s/n, 31080 Pamplona, Spain.
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Abstract |
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Abstract—An association of increased apoptosis with overexpression of the proapoptotic protein Bax-
has been reported in the left
ventricle of adult spontaneously hypertensive rats (SHR). Both
alterations were corrected in SHR that received long-term treatment
with the AT1 antagonist losartan. To
gain insight into the regulation of cardiac Bax- protein in genetic
hypertension, we investigated the expression of the protein p53 (a
BAX gene transcription factor) and BAX mRNA in the left
ventricle of 30-week-old Wistar-Kyoto rats (WKY), SHR, and SHR treated
with losartan (20 mg · kg-1 ·
d-1) during 14 weeks before death. The expression of p53
and Bax proteins was assessed by Western blot analysis. The
expression of BAX mRNA was assessed by Northern blot analysis.
The density of apoptotic cells was assessed by direct
immunoperoxidase detection of biotin-labeled deoxyuridine
nucleotides. Compared with WKY, untreated SHR exhibited
increased apoptosis (P<0.05), increased Bax-
protein (P<0.05), and similar levels of p53 protein and
BAX mRNA. Losartan given long term was associated with the
normalization of apoptosis and Bax- protein expression. The
expression of BAX mRNA was decreased (P<0.05) in
treated SHR compared with untreated SHR. No changes in the expression
of p53 protein were observed in losartan-treated SHR. These
results suggest that overexpression of the Bax- protein seen in the
left ventricle of adult SHR with increased apoptosis is not
related to a p53-mediated upregulation of BAX gene
transcription. Our data also suggest that normalization of Bax-
protein observed in SHR after long-term blockade of
angiotensin II type 1 receptors may be due to the
inhibition of BAX gene transcription.
Key Words: apoptosis • BAX gene • protein, Bax- • ventricular function, left • p53 • rats, inbred SHR
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Introduction |
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Cardiomyocyte apoptosis is increasingly recognized as a contributing cause of cardiomyocyte loss with important pathophysiological consequences.1 2 For instance, increased apoptosis has been demonstrated recently in the hypertrophied left ventricle of young,3 adult,4 and aged5 spontaneously hypertensive rats (SHR). It has been suggested that apoptosis might be a mechanism involved in the reduction of cardiomyocyte mass that accompanies the development of interstitial fibrosis and the transition from stable compensation to heart failure in hypertensive heart disease.6
We have shown recently that an association exists between increased
apoptosis and overexpression of the proapoptotic
Bax- protein in cardiomyocytes from the hypertrophied
left ventricle of adult SHR.7 Long-term blockade of
angiotensin II type 1 (AT1) receptors
prevented Bax- overexpression and normalized apoptosis in
the left ventricle of SHR.7 These results suggested that
the long-term effect of arterial hypertension in
combination with local mechanisms (ie, the interaction of
angiotensin II with the AT1 receptor)
may facilitate cardiomyocyte apoptosis in the left
ventricle of SHR by way of stimulation of Bax- protein.
The BAX gene is a 6-exon, 4.5-kb gene, and a member of the
Bcl-2 gene family that maps to chromosome 1q31.2. in the
rat.8 It encodes different isoforms: Bax-,
Bax-ß, Bax-
, and Bax-
. The heart has been shown to contain only
the 21-kDa Bax- protein.9 The expression of
BAX has been found to be upregulated at the transcriptional
level by p53.10 In fact, the BAX gene
promoter was shown to contain 4 p53-binding sites that could be
specifically transcriptionally transactivated by
p53.11
This study was designed to determine whether the transcription of BAX gene is upregulated in the left ventricle of adult SHR and whether this is associated with changes in p53. In addition, we also determined whether blockade of AT1 receptors with losartan interferes with the transcriptional regulation of BAX in SHR.
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Methods |
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Study Design
All procedures were performed in accordance with European Community guidelines for ethical care and use of laboratory animals (Directive 86/609). The rats were provided by Harlan UK Limited (Bicester). The study followed the same design recently described by our team.7 Sixteen-week-old normotensive Wistar-Kyoto rats (WKY) (n=8) and 16-week-old untreated SHR (n=8) were observed in our laboratory for 14 weeks and killed at 30 weeks of age (groups WKY and SHR), and 16-week-old SHR (n=8) were treated with losartan (20 mg · kg-1 · d-1, PO) for 14 weeks and killed at 30 weeks (group SHR-L). Systolic blood pressure (SBP) was measured every 2 weeks by the standard tail-cuff method with the use of a LE 5007 Pressure Computer (Letica Scientific Instruments).
Preparation of Tissue Samples
All the animals were anesthetized with 30 mg/kg IP of
sodium thiopental before death and were retrogradely perfused through
the abdominal aorta as previously reported.7 After
perfusion, the hearts were removed, the cardiac weight was measured,
and the cardiac index was calculated by dividing the heart weight by
the body weight for each animal. One portion of the left ventricle was
fixed by immersion in 10% buffered formalin for 24 hours and embedded
in paraffin. Coronal heart sections (5 µm thick) obtained from
the equator of the heart were prepared for morphological studies.
Another portion of the left ventricle was immediately stored at
-70°C for Northern blot and Western blot analysis.
In Situ Detection of Apoptosis
The TUNEL methodology used for in situ end-labeling of DNA
fragments was the same as recently described.7 Nuclei
labeled with diaminobenzidine after TUNEL assay were quantified with an
image analyzer. The presence of apoptotic cells was
determined by means of the apoptotic density; the
apoptotic density was calculated as the number of
positive-staining nuclei per milimeter2 of
myocardial surface area.
Northern Blot Analysis
Total RNA from frozen left ventricular tissue
samples was prepared with the method of Chomczynski and
Sacchi,12 with the use of Ultraspec RNA reagent (Biotecx
Laboratories Inc). The purified RNA was quantified spectrometrically
and run on ethidium bromide–stained agarose gels to check for its
integrity. Total RNA (20 µg) was separated in a 1.3% denaturing
formaldehyde agarose gel, blotted on nylon membranes by overnight
capillary blotting, and fixed by UV irradiation. Blots were
prehybridized in 5x SSC, 50% formamide, 5x Denhardt's solution,
50 mmol/L sodium phosphate pH 6.5, 0.1% SDS, and 100 µg/mL
salmon sperm DNA at 42°C. Hybridization was performed in 50%
formamide solution at 42°C for 16 hours. Membranes were hybridized
with a 505-bp fragment that encodes for rat BAX cDNA. The fragment was
labeled with [-32P]dCTP with the use of the
Multiprime DNA labeling kit (Amersham Ibérica). The concentration
of the labeled probe in the hybridization solution was
1x106 cpm/mL. After hybridization, membranes
were successively washed twice in 2x SSC/0.1% SDS at room temperature
for 20 minutes, twice in 1x SSC/0.1% SDS at 42°C for 20 minutes,
and twice in 0.2x SSC/0.1% SDS at 65°C for 15 minutes.
Standardization was performed by hybridization of the same membrane
with a probe from rat GAPDH cDNA. After
autoradiography, quantification of the signals was
performed by densitometric analysis.
Western Blot Analysis
For immunoblot assay of Bax- in the left
ventricle, we used the procedure recently described.7 For
the immunodetection of p53, 60 µg of proteins was separated in a 12%
SDS–polyacrylamide gel and transferred to nitrocellulose
membranes with the use of a Mini-Protean II Dual Stab Cell (BioRad).
Membranes were blocked with 0.05% Tween and 10% dry skim milk in PBS
(100 mmol/L sodium chloride, 80 mmol/L disodium phosphate,
25 mmol/L disodium monobasic phosphate, pH=7.5) overnight at 4°C
and incubated with a mouse monoclonal anti-p53 (Pab240, Santa Cruz
Biotechnology, Inc) at 1:400 in blocking solution for 1 hour at room
temperature. After the proteins were washed, specific bound antibody
was detected by a peroxidase-conjugated anti-mouse IgG (Santa Cruz
Biotechnology, Inc) at 1:8000 in PBS and visualized by the ECL-Plus
chemiluminescence detection system (Amersham). Values for p53 and
Bax- protein were expressed as arbitrary optical density units
(AU).
Immunohistochemical Study of Bax- Protein
For the immunohistochemical detection of Bax-, avidin-biotin
immunoperoxidase staining was performed as described
previously,13 with some modifications. The deparaffinized
and rehydrated sections were treated by microwave irradiation twice for
3 minutes at 550 W with 10 mmol/L citrate buffer (pH=6). After
blocking with 4% normal goat serum was completed, sections were
incubated for 1 hour at room temperature first with a rabbit polyclonal
anti-mouse Bax antibody (Pharmingen) at a dilution of 1:100 in PBS ,
then with goat-biotinylated anti-rabbit IgG (Vector) at 1:100 in PBS,
and finally with avidin-biotin complex that contained horseradish
peroxidase (Vector). Immunostaining was detected with
diaminobenzidine (Sigma), and tissues were counterstained with
hematoxylin (Sigma). For all data presented, the specificity of
the immunostaining results was confirmed by use of both
preimmune serum, which produced entirely no background, and by
preadsorption of anti-Bax- antibody with competing peptide, which
completely abrogated the immunostaining (not shown). To
develop a semiquantitative scale, the amount of Bax- was graded on a
scale of 0 to 2+: 0 indicates the absence of Bax-; 1+, mild
deposits; and 2+, intense deposits.
Statistical Analysis
Results are presented as mean±SEM computed from the
average measurements obtained from each group of rats. Normal
distribution of data was checked with the Shapiro-Wilk test. A Levene
statistic test was performed to check the homogeneity of variances.
Differences among the 3 groups of rats were tested by 1-way ANOVA.
Subsequent analysis for significant differences between the 2
groups was performed with the use of the multiple comparison
Student-Newman-Keuls test. When the normal distribution test was
significant, the 
2 method (Kruskal-Wallis) was
used to analyze the differences among the 3 groups of animals.
For nonquantitative data, a 2 method (Pearson)
was used to analyze the differences among the 3 groups of
animals. The significance level was assumed at P<0.05.
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Results |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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General Parameters
As shown in Table 1, at 30 weeks of age, SBP was higher (P<0.05) in SHR than in WKY. Consistent with data previously reported,7 losartan diminished (P<0.05) SBP in SHR-L compared with SHR (Table 1). Thus, no significant differences were found in SBP between SHR-L and WKY (Table 1).
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Both cardiac weight and index were greater (P<0.05) in SHR than in WKY (Table 1). Thus, SHR were considered to have left ventricular hypertrophy (LVH). The values of the 2 parameters were not significantly different in SHR-L than in WKY (Table 1), which indicates that losartan given long-term was associated with the regression of LVH already present in 16-week-old SHR.4
The apoptotic density was increased (P<0.05) in the left ventricle of SHR versus WKY (Table 1). After treatment with losartan, the apoptotic density decreased (P<0.05) in SHR-L to values similar to those measured in WKY (Table 1).
Expression of p53 Protein
As shown in Fig 1, no significant
differences were found in the expression of p53 among the 3 groups of
animals. Optical density values for p53 were 0.89±0.15 AU for WKY,
1.14±0.16 AU for SHR, and 1.28±0.29 AU for SHR-L.
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Expression of BAX mRNA and Bax- Protein
A representative Northern blot of left
ventricular BAX mRNA is shown in Fig 2 (top). BAX mRNA levels were similar in
the left ventricle of WKY and SHR (1.12±0.07 versus 1.02±0.05) (Fig 2, bottom). Left ventricular BAX mRNA levels were
decreased (P<0.05) in SHR-L (0.75±0.06) versus WKY and SHR
(Fig 2, bottom).
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The amount of Bax- protein was higher (P<0.05) in SHR
(0.45±0.10 AU) than in WKY (0.19±0.03 AU) (Fig 3). The expression of Bax- protein
(0.21±0.04 AU) was diminished (P<0.05) in SHR-L compared
with SHR (Fig 3). No significant differences in Bax- protein
were observed between SHR-L and WKY.
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Left Ventricular Deposition of Bax- Protein
The positive Bax- immunoreactivity was primarily confined to
the cardiomyocytes, which were easily distinguished from
other nonmyocytes cells because of their morphology:
well-shaped, cylindrical, and elongated cells that exhibit
cross-striations and are branched. The photomicrographs in Fig 4 show Bax- deposition in the left
ventricle of the 3 experimental rat groups. A semiquantitative
analysis of Bax- deposition was performed on all rats (Table 2). Although more animals exhibited no
deposition or a low grade of deposition of Bax- in the WKY group,
more animals exhibited high-grade deposition in the SHR group. After
losartan was given, the distribution of SHR-L was displaced to
a low grade of deposition of Bax-. The analysis of the
frequencies of distribution demonstrated differences among the 3 groups
of animals (P<0.05).
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Discussion |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
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The results of the current study provide the first indication that the expression of the BAX mRNA is unchanged in the left ventricle of adult SHR versus normotensive WKY. In addition, the reported data indicate that the expression of p53 protein is normal in the hypertrophied left ventricle of adult SHR that exhibit increased apoptosis of cardiomyocytes.
Previous observations suggest that BAX may function as a
primary response gene in a p53-regulated pathway in some types of
cells.10 11 Recently, Leri et al14 have
shown that stretching of adult rat ventricular
cardiomyocytes in vitro was coupled with enhanced p53
expression and binding to the promoter of BAX gene, which
was followed by enhanced Bax- protein expression and
apoptosis. Thus, the authors suggest that activation of p53
results in the induction of BAX gene and increased
susceptibility of cardiomyocytes to undergo
apoptosis.14 Our results of normal levels of
p53 and BAX mRNA in SHR do not support a role for the above mechanism
of cardiomyocyte apoptosis in this in vivo model of
genetic hypertension. This agrees with previous data that show that p53
transcripts are barely detectable in the adult rat
myocardium and do not seem to increase with cardiac
hypertrophy.15 Nevertheless, because
upregulation in p53 binding activity may result from both increased
expression of the protein and phosphorylation of its
regulatory sites, without changes in its level of
expression,16 caution is required to exclude definitively
the participation of p53 in cardiac apoptosis in SHR.
Miyashita et al17 demonstrated that levels of Bax-
protein can be posttranslationally regulated by Bcl-2, a 25-kDa protein
that blocks apoptosis. Gene transfer–mediated elevations in
Bcl-2 protein resulted in increases in Bax- by a reduction in the
rate of Bax- degradation in some types of cell lines.17
In a previous work, we have found that the concentration of Bcl-2 is
increased by 53% in the left ventricle of SHR compared with
WKY.7 Thus, a reasonable speculation is that the
interaction of Bcl-2 with Bax-, which leads to formation of
heterodimers or complexes with other stoichiometry,18
somehow stabilizes the Bax-, and thus leads to increases in the
steady-state levels of this protein in the left ventricle of adult SHR.
Nevertheless, alternative possibilities also deserve to be considered.
These include differences in the levels or activity of proteases
involved in proteolytic degradation, kinases and phosphatases that
theoretically could control phosphorylation of Bax-,
and non-Bcl-2 family proteins that might bind to Bax-.
A second finding of this study is that chronic treatment with
losartan was associated with a parallel diminution of BAX mRNA
and Bax- protein levels in the left ventricle of SHR. Interestingly,
no changes in p53 expression were observed in losartan-treated
SHR. Together, these results suggest that long-term blockade of
AT1 receptors in the left ventricle of SHR
results in downregulation of BAX transcription through a
p53-independent pathway. Some experimental observations support this
possibility. First, stretch-mediated release of angiotensin
II is coupled with stimulation of AT1 receptors
and an increased level of Bax- protein in adult rat
ventricular cardiomyocytes.14
Thus, the interaction of angiotensin II with the
AT1 receptor might participate in the regulation
of BAX transcription in the left ventricle of SHR. Second,
it has been shown that interleukin-6 downregulates BAX mRNA
levels.19 However, because this cytokine also
induces cardiac hypertrophy,20 it is unlikely
that losartan treatment, which is associated with LVH
regression in SHR, results in stimulation of interleukin-6. Third, we
have reported previously that the blockade of AT1
receptors with losartan resulted in decreased expression of
Bax- in the absence of changes in the expression of Bcl-2 in left
ventricular cells of SHR.7 Thus, it is
unlikely that the ability of losartan to reduce the left
ventricular levels of Bax- protein can be the result of
enhanced degradation of the protein in treated SHR.
Finally, in this study we found that losartan given long-term regressed LVH and prevented cardiomyocyte apoptosis in treated SHR. Thus, it seems that the treatment of SHR with losartan resulted in decreased cardiac mass despite a diminished loss of cardiomyocytes. This apparent discrepancy can be explained by the following considerations. First, it is unlikely that small changes in the density of cardiomyocytes, such as those observed in this work, may have a final significant effect on cardiac mass. Second, because cardiomyocytes may replicate in some conditions in the adult heart,21 further studies are required to assess whether losartan given long-term modifies the balance between cardiomyocyte apoptosis and replication in adult SHR. Third, it is possible that part of the cardiac weight decrease observed in losartan-treated SHR is due to a decrease in extracellular matrix. In experiments performed in our laboratory, we have found that the deposition of collagen fibers was significantly reduced in the left ventricle of adult SHR treated with losartan long-term versus untreated SHR.22
In summary, our results suggest that overexpression of the
proapoptotic Bax- protein present in the left ventricle
of adult SHR is not due to p53-dependent upregulation of BAX
gene transcription. Further studies are required to determine whether
Bax- overexpression can be the result of some kind of alteration in
its posttranscriptional processing (ie, decreased degradation). In
addition, our results suggest that the reduction in Bax- levels
observed in SHR that received long-term blockade of
AT1 receptors can be related to inhibited
transcription of the BAX gene. Whether this is the
consequence of the interference with an angiotensin
II–dependent pathway that regulates the transcription of
BAX gene deserves further investigation.
Received July 31, 1998; first decision September 15, 1998; accepted January 25, 1999.
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References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Anversa P, Kajstura J, Olivetti G. Myocyte death in heart failure. Curr Opin Cardiol. 1996;11:245–251.[Medline] [Order article via Infotrieve]
2. Anversa P, Olivetti G, Leri A, Liu Y, Kajstura J. Myocyte death and ventricular remodeling. Curr Opin Nephrol Hypertens. 1997;6:169–176.[Medline] [Order article via Infotrieve]
3.
Hamet P, Richard L, Dam TV, Teiger E, Orlov SN,
Gaboury L, Gossard F, Tremblay J. Apoptosis in target organs in
hypertension. Hypertension. 1995;26:642–648.
4.
Díez J, Panizo A, Hernández M, Vega F,
Sola I, Fortuño MA, Pardo J. Cardiomyocyte apoptosis
and cardiac angiotensin-converting enzyme in spontaneously
hypertensive rats. Hypertension. 1997;30:1029–1034.
5.
Li Z, Bing OHL, Long X, Robinson KG, Lakatta EG.
Increased cardiomyocyte apoptosis during the
transition to heart failure in the spontaneously hypertensive rat.
Am J Physiol. 1997;272:H2313–H2319.
6. Díez J, Fortuño MA, Ravassa S. Apoptosis in hypertensive heart disease. Curr Opin Cardiol. 1998;13:317–325.[Medline] [Order article via Infotrieve]
7.
Fortuño MA, Ravassa S, Etayo JC, Díez J.
Overexpression of Bax protein and enhanced apoptosis in the
left ventricle of spontaneously hypertensive rats: effects of
AT1 blockade with losartan.
Hypertension. 1998;32:280–286.
8. Matsuda Y, Kusano H, Tsujimoto Y. Chromosomal assignment of the Bcl2-related genes, Bcl21 and Bax, in the mouse and rat. Cytogenet Cell Genet. 1996;74:107–110.[Medline] [Order article via Infotrieve]
9. Krajewski S, Krajewska M, Shabaik A, Miyashita T, Wang HG, Reed JC. Immunohistochemical determination of in vivo distribution of Bax, a dominant inhibitor of Bcl-2. Am J Pathol. 1994;145:1323–1336.[Abstract]
10. Miyashita T, Krajewski S, Krajewska M, Wang HG, Lin HK, Lieberman DA, Hoffman B, Reed JC. Tumor suppressor p53 is a regulator of bcl-2 and bax gene expression in vitro and in vivo. Oncogene. 1994;9:1799–1805.[Medline] [Order article via Infotrieve]
11. Miyashita T, Reed JC. Tumor suppressor p53 is a direct transcriptional activator of the human bax gene. Cell. 1995;80:293–299.[Medline] [Order article via Infotrieve]
12. Chomczynski P, Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987;162:156–159.[Medline] [Order article via Infotrieve]
13.
Díez J, Panizo A, Hernández M, Pardo J.
Is the regulation of apoptosis altered in smooth muscle cells
of adult spontaneously hypertensive rats? Hypertension. 1997;29:776–780.
14. Leri A, Claudio PP, Li Q, Wang X, Reiss K, Wang S, Malhotra A, Kajstura J, Anversa P. 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.[Medline] [Order article via Infotrieve]
15.
Kim KK, Soonpaa MH, Daud AI, Koh GI, Kim JS, Field LJ.
Tumor suppressor gene expression during normal and pathologic
myocardial growth. J Biol Chem. 1994;269:22607–22613.
16.
Hupp TR, Lane DP. Regulation of the cryptic
sequence-specific DNA-binding function of p53 by protein kinases.
Cold Spring Harbor Quant Biol. 1994;59:195–206.
17.
Miyashita T, Kitada S, Krajewski S, Horne WA, Delia D,
Reed JC. Overexpression of the Bcl-2 protein increases the half-life of
p21Bax. J Biol Chem. 1995;270:26049–26052.
18. Yin XM, Oltvai ZN, Korsmeyer SJ. BH1 and BH2 domains of Bcl-2 are required for inhibition of apoptosis and heterodimerization with Bax. Nature. 1994;369:321–333.[Medline] [Order article via Infotrieve]
19. Lotem J, Sachs L. Regulation of bcl-2, bcl-XL and bax in the control of apoptosis by hematopoietic cytokines and dexamethasone. Cell Growth Diff. 1995;6:647–653.[Abstract]
20.
Pennica D, King KL, Shaw KJ, Luis E, Rullamas J, Luoh
SM, Darbonne WC, Knutzon DS, Yen R, Chien KR, Barker JB, Wood WI.
Expression cloning of cardiotrophin 1, a cytokine that induces
cardiac myocyte hypertrophy. Proc Natl Acad Sci
U S A. 1995;92:1142–1146.
21.
Anversa P, Kajstura J. Ventricular myocytes
are not terminally differentiated in the adult mammalian heart.
Circ Res. 1998;83:1–14.
22. Varo N, Etayo JC, Zalba G, Beaumont J, Iraburu M, Montiel C, Gil MJ, Monreal I, Díez J. Losartan inhibits the post-transcriptional synthesis of collagen type I and reverses left ventricular fibrosis in spontaneously hypertensive rats. J Hypertens. 1999;17:107–114.[Medline] [Order article via Infotrieve]
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