| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Physiology, New York Medical College, Valhalla, New York 10595
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONGRANTSREFERENCES |
|---|
, TNFß, and caspase 9 (microarray, real-time PCR), as well as increased caspase 9 and caspase 3 activity, whereas expression of TNFR1, TNF-converting enzyme (TACE), Bcl-2, Bcl-X(L), Bid, Bax, caspase 8, and caspase 3 were unchanged. In vessel culture (18 h) incubation of aged coronary arteries with a TNF blocking antibody or the NO donor S-nitroso-penicillamine (SNAP) decreased apoptotic cell death. Incubation of young arteries with exogenous TNF increased caspase 9 activity and elicited endothelial apoptosis, which was attenuated by SNAP. Inhibition of NO synthesis in cultured young coronary arteries also induced apoptotic cell death and potentiated the apoptotic effect of TNF. Thus we propose that age-related upregulation of TNF and caspase 9 and decreased bioavailability of NO promote endothelial apoptosis in coronary arteries that may lead to impaired endothelial function and ischemic heart disease in the elderly. TACE activity; caspase 9; small inhibitory RNA; senescence; cytokine; inflammation
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONGRANTSREFERENCES |
|---|
With advancing age, coronary arteries were shown to undergo complex phenotypic and functional alterations (7, 8), including endothelial vasodilator dysfunction (11), downregulation of eNOS and decreased NO production, increased activity of NAD(P)H oxidases, and upregulation of proinflammatory cytokines (7, 8), which likely affect the survival of vascular cells (13, 22). Recent studies suggest that advanced age itself, even in the absence of other disease-related proapoptotic factors (e.g., ox-LDL; Ref. 18) may promote apoptotic cell death in various tissues, including peripheral arteries (4). Also, accelerated aging in different mutant mouse models is associated with an imbalanced apoptotic cell loss (30). High number of passages in vitro was also shown to enhance the sensitivity of endothelial cells toward apoptotic stimuli (13).
The regulation and execution of apoptosis in endothelial cells is a complex process involving paracrine factors, membrane receptors, interaction of pro- and anti-apoptotic factors and cysteinyl aspartate-specific proteases (caspases). Recent studies suggest that in aging there is an imbalance in the expression of pro- and anti-apoptotic genes resulting in an enhanced apoptosis in the myocardium (19), central nervous system (24), skeletal muscle (10), lung (33), and liver (2, 33). Yet, age-related alterations in the expression of pro- and anti-apoptotic genes in coronary arteries have not been elucidated.
On the basis of the aforementioned findings we hypothesized that age-related changes in gene expression create a proapoptotic microenvironment, which results in enhanced endothelial cell death in coronary arteries.
|
METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONGRANTSREFERENCES |
|---|
Isolation of coronary vessels.
Coronary arteries were isolated from the left ventricle of young and aged rat hearts as previously described (7, 8). Samples were cleaned of adhering tissue and snap-frozen in liquid nitrogen.
Detection of apoptotic cell death by ELISA.
Vessels were lysed and cytoplasmic histone-associated DNA fragments, which indicate apoptotic cell death, were quantified by the Cell Death Detection ELISAPlus kit (http://www.roche-applied-science.com). Results are reported as arbitrary optical density (OD) units normalized to protein concentration.
TUNEL assay.
DNA fragmentation was detected in coronary arteries in situ by using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) on cryosections (thickness: 5 µm) of the heart of young and aged rats. After proteinase K (2.5 µg/ml) treatment, DNA fragments in the sections were labeled with 2 nmol/l digoxigenin-conjugated dUTP and 0.1 U/µl TdT for 2 h at 37°C. The incorporation of digoxigenin-16-dUTP into DNA was determined by incubating the sections with FITC-anti-digoxigenin (1:50, Sigma Chemical) at room temperature for 60 min. The sections were immunolabeled for smooth muscle -actin, and the nuclei were stained with propidium iodide.
RNA preparation and analysis of mRNA expression with microarrays and real-time PCR.
Total RNA from coronary arteries was isolated with Mini RNA Isolation Kit (Zymo Research, Orange, CA) and was reverse transcribed using SuperScript II RT (Life Technologies, Gaithersburg, MD) as described previously (7, 8).
Real-time RT-PCR technique was used to analyze mRNA expression, as previously described (7, 8). PCR reactions were performed in the Roche Molecular Biochemicals LightCycler System. The housekeeping gene ß-actin was used for internal normalization. Oligonucleotides used for real-time quantitative RT-PCR are listed in Table 1. Fidelity of the PCR reaction was determined by melting temperature analysis and visualization of product on a 2% agarose gel.
|
Microdissection of coronary arterial endothelium.
Microdissection was performed using a P.A.L.M. Microlaser Technologies system (Bernried, Germany) on frozen sections (thickness: 10 µm, stored on -80°C) of aged and young hearts stained by hematoxylin. For RNA analyses, the endothelial layer of multiple coronary arteries was dissected and catapulted into 20 µl of cDNA reaction mixture and stored on ice until cDNA synthesis. RNA was extracted Mini RNA Isolation Kit (Zymo Research) as described.
Western blotting.
Using coronary arterial samples from young and aged rats, we performed Western blotting as described (7, 8) using primary antibodies directed against cleaved caspase 9, cleaved caspase 3 (Cell Signaling, 1:100), truncated Bid (Oncogene, 1:100), TRADD, and TNFR1 (Santa Cruz Biotechnology, 1:100). Anti-ß-actin (Novus Biologicals, 1:5,000) was used for normalization.
Vascular caspase activities.
Isolated coronary arteries from aged and young rats were homogenized in lysis buffer, and caspase activities were measured using the caspase 9, caspase 3, and caspase 8 Colorimetric Activity Assay kits, according to the manufacturer’s instruction (Chemicon International). Optical density values were normalized to the sample protein concentration.
Vascular TACE activity.
TNF-converting enzyme (TACE) is a membrane-bound metalloprotease-disintegrin in the ADAM family (ADAM-17). To measure TACE activity, vessel samples were homogenized in Tris buffer (10 mmol/l, pH 7.5, 0°C), containing 300 mmol/l sucrose, 1 mmol/l DTT, and protease inhibitors (10 µg/ml leupeptin, 2 µg/ml aprotinin, 1 µg/ml soybean trypsin inhibitor, 0.2 mg/ml 1-antitrypsin, 10 µmol/l pepstatin A). Crude membranes were separated by precipitation at 15,000 g for 20 min after a 15-min incubation period on ice after addition of CaCl2 (10 mmol/l, in Tris). The resulting pellet was dissolved in Tris buffer containing 1% Nonidet P-40 and protease inhibitors followed by centrifugation at 15,000 gav for 5 min. The supernatant (referred to in the following as detergent extract) was used for the oligopeptide hydrolysis assay. Detergent extract, 50 µl (protein concentration 
5 mg/ml), was added to the incubation medium consisting of Tris buffer (10 mmol/l; pH 7.5), MgCl2 (1 mmol/l), CaCl2 (0.2 mmol/l), and protease inhibitors. Samples incubated with EDTA (5 mmol/l) were used as negative controls. The reaction was started by addition of the substrate peptide Abz-LAQA-VRSSSR-Dpa (10 µg/ml) to the incubation medium. After the incubation (37°C, for 60 min) the reaction was stopped by addition of HCl (0.1 mol/l). Specific peptide breakdown was determined by the System Gold HPLC system (Beckman Coulter) equipped with C18 guard and 150 x 2.0 mm MiniBore Ultrasphere 5µ C18 column with a 20–100% acetonitrile [0.09% trifluoracetic acid (TFA), vol/vol]/H2O (0.1% TFA, vol/vol) gradient. Separation was monitored at fluorescence excitation = 320 nm, emission = 420 nm. Data are expressed as arbitrary units (AU/mg) corresponding to the peak area of the breakdown product in the chromatogram.
Vascular TACE expression.
TACE mRNA expression was assessed in young and aged coronary arteries using RT-PCR. To localize TACE expression in sections of coronary arteries, immunolabeling was carried out as described previously (7, 8) with a primary antibody against TACE (Novus Biologicals, 1:80, overnight, at 4°C), smooth muscle -actin (Sigma, 1:1,000, 1 h, at room temperature), and CD31 (PECAM, an endothelium-specific marker; 1:50, Pharmingen) using the Zenon rabbit IgG labeling Kit (Molecular Probes, Eugene, OR). Images were captured using an Olympus BX61 fluorescent microscope. TACE mRNA expression was also assessed in cultured rat coronary arterial endothelial cells (CAEC, see below) and vascular smooth muscle cells (VSMC, SV40LT-SMC clone HEP-SA; American Type Culture Collection, Manassas, VA).
Vessel culture studies.
Coronary arteries of young and aged rats were incubated for 18 h (at 37°C) in a vessel culture system as previously described (28) in the absence or presence of recombinant TNF (1–100 ng/ml). Coronary arteries from aged rats were cultured (for 18 h) in the absence and presence of the NO donor S-nitroso-penicillamine (SNAP, 10-6 mol/l) or the NO synthesis inhibitor N
-nitro-L-arginine methylester (L-NAME, 3 x 10-4 mol/l) or a monoclonal anti-rat TNF antibody (R&D Systems) to neutralize bioactivity of endogenous TNF (28). In separate experiments young coronary arteries were incubated with TNF in the absence and presence of L-NAME or SNAP. After the culture period apoptotic cell death and/or caspase 9 activity were detected as described.
Cell culture studies.
Primary rat CAECs (Celprogen, San Pedro, CA) were maintained in culture according to the vendor’s guidelines and harvested after passage 3 and passage 9 (referred to as "young" and "aged" CAEC, respectively). Activity and expression of caspase 9 were measured as described.
To assess the effect of TNF, young CAEC were incubated (18 h) in the absence or presence of recombinant TNF (10–100 ng/ml). Apoptotic cells were detected by the ApoAlert Annexin V Apoptosis Kit (http://www.clontech.com). This assay takes advantage of the fact that phosphatidylserine is translocated to the outer plasma membrane after the induction of apoptosis and that the annexin V protein has a strong, specific affinity for phosphatidylserine. Images were captured using an Olympus confocal microscope. TNF-induced changes in caspase 9 activity and expression were also determined.
Downregulation of caspase 9 in CAEC using RNAi.
Downregulation of caspase 9 in CAEC was achieved by RNA interference (RNAi, a phenomenon in which double-stranded RNA specifically suppresses expression of a target protein by inducing the degradation of the target RNA) using the siLentGene U6 Cassette RNA Interference System according to the manufacturer’s guidelines (Promega, Madison, WI). This system allows production and transfection of small inhibitory RNA (siRNA) sequences under control of an engineered U6 promoter sequence coupled with a specific U6 polymerase terminator. Three different siRNA sequences were screened for optimal gene silencing. The following downstream primer was used in the experiments: 5'-GCCCAAGCTGTTCTTCATC-3'. CAEC cell density at transfection was 30%. Specific gene silencing was verified by Western blotting. CAEC transfected with anti-caspase 9 siRNA or scrambled siRNA on day 4 after the transfection were incubated with TNF (10 ng/ml, for 0, 2, 4, or 6 h). Then, DNA fragmentation assay was performed as described.
Data analysis.
Data are expressed as means ± SE. Densitometric ratios and enzyme activity values were normalized to the respective control mean values. Statistical analyses of data were performed by Student’s t-test or by two-way ANOVA followed by the Tukey post hoc test, as appropriate. If two data sets had different variances, then the Welch modified t-test was used. The array data was analyzed by the pairwise comparisons method as described (8). P < 0.05 was considered statistically significant.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONGRANTSREFERENCES |
|---|
|
2.5%) compared with vessels of young rats (0.5%). TUNEL-positive cells were present predominantly in the endothelium of aged coronary arteries (Fig. 1, B and C). An increased number of TUNEL-positive cells were also observed in the myocardium of aged rats (not shown), confirming previous reports (14).
mRNA expression.
Experiments using the Apoptosis Gene Arrays indicated an increased expression of TNF, TNFß, and caspase 9 in aged coronary arteries, whereas expression of other apoptosis-related gene transcripts were similar to that in control vessels by this method (Table 2). Using real-time PCR, we detected an increased presence of caspase 9 mRNA in intact aged coronary arteries (Fig. 2A), as well as in the endothelium of aged coronary arteries obtained by laser capture microdissection (Fig. 2B). Increased caspase 9 mRNA content was also present in aged CAEC (Fig. 2D). In coronary arteries of aged rats a significantly increased mRNA expression of TNF and TNFß (Fig. 3, A and B) was detected, confirming our recent findings (7, 8). The vascular mRNA expressions of caspase 8 and caspase 3, Bcl-2, Bcl-X(L), Bid, Bax, TNFR1, TRADD, and FADD were unaffected by aging (Table 2).
|
|
|
|
|
|
blocking antibody, but was unaffected by L-NAME (Fig. 5A). In cultured coronary arteries of young and aged rats incubation with recombinant TNF (18 h incubation) induced apoptosis in a concentration-dependent manner (Fig. 5B). TUNEL assay showed that in TNF-treated coronary arteries apoptotic cells (green) were predominantly localized to the endothelium (Fig. 5C, arrowheads), whereas the media (blue, smooth muscle -actin staining) was relatively free from TUNEL-positive cells. In cultured coronary arteries of young rats inhibition of NO synthesis also induced apoptosis and potentiated the apoptotic effects of TNF (Fig. 6A). In cultured coronary arteries of young rats TNF-induced apoptosis was reduced by the NO donor SNAP (Fig. 6B). In young coronary arteries caspase 9 activity was significantly increased by TNF, whereas it was unaffected by SNAP or L-NAME (Fig. 7A).
|
|
|
induced apoptosis in cultured CAEC, as shown by annexin V staining (Fig. 5D). Annexin V-positive cells did not exhibit significant propidium iodide staining, indicating that TNF induces primarily apoptosis, not necrosis, in endothelial cells (not shown). In cultured CAEC TNF significantly increased caspase 9 activity (Fig. 7B) and caspase 9 expression [caspase 9, ß-actin mRNA: control, 100 ± 11%; TNF treated (10 ng/ml, 18 h), 188 ± 18%]. Downregulation of caspase 9 protein in CAEC was achieved by RNAi (by 80% on day 4 after siRNA treatment) as illustrated in Fig. 7C. Downregulation of caspase 9 levels resulted in partial protection of CAEC against TNF-induced apoptosis (Fig. 7D). |
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONGRANTSREFERENCES |
|---|
The coronary arterial endothelium in healthy vessels has vasodilative, anticoagulant, and angiogenic functions (6). An age-related increased loss of coronary endothelial cells may impair cardiac blood supply and create a procoagulant environment, favoring platelet adhesion and thrombus formation promoting the development of CAD (6). Endothelial apoptosis may also contribute to the age-related structural remodeling of the coronary vasculature (3, 27).
Recent studies suggest that age-related functional alterations in the cardiovascular system are due to alterations in gene expression profile (7, 8, 15). To elucidate the underlying mechanisms of enhanced endothelial apoptosis in aged coronary arteries, we analyzed the expression of apoptosis-related genes that are involved in induction, execution, and regulation of programmed cell death. Among the apoptosis-related signaling molecules, the expression of caspase 9 was significantly upregulated in the endothelium (Table 2; Fig. 2, A and B), whereas expression of other caspases (e.g., caspase 3, caspase 8) seems to be unaffected by aging (Table 2). Increased presence of active caspase 9 and the downstream effector caspase 3 (Table 3) and increased caspase 9 (Fig. 2C) and caspase 3 activities (Table 4) were present in aged vessels. Upregulated caspase 9 expression and activity was also present in aged CAEC (Fig. 2, D and E), suggesting that upregulation/activation of caspase 9 may contribute to age-related endothelial apoptosis. Increased activity of caspase 3 and/or caspase 9 is also present in the liver (33), brain (24), and skeletal muscle (10) of aged rats and lymphocytes of aged humans (1). Expressions of the protooncogene Bcl-2, which is inversely related to apoptotic cell death (6), and that of the proapoptotic homolog Bax, Bad, and Bid or the Bcl family member Bcl-X(L) were unaltered in aged coronary vessels (Table 2). Similar results were obtained in cardiomyocytes (19, 21), skeletal muscle (10), and liver (33) of aged F344 rats, despite the presence of enhanced apoptosis in these organs. The increased presence of truncated Bid found in aged coronary arteries may be related to the increased activity of caspase 8 (32) (Table 4).
Our present and previous findings (7, 8) showed that expression of the proinflammatory cytokine TNF and that of TNFß (which acts on the same receptor) significantly increased in aged coronary arteries (Table 2, Fig. 3). Previously we demonstrated that it is the VSMC that abundantly express TNF in aged coronary arteries (8). Previous studies have also reported age-related increases in plasma TNF concentrations in humans (5) and experimental animals (31). Since the early work of Robaye and coworkers (22) TNF has been recognized as one of the most potent inducers of programmed cell death in endothelial cells. However, TNF in the smooth muscle cells is synthesized as a membrane-bound precursor that has to be cleaved to generate secreted TNF, which acts as a paracrine mediator. This is the first study to demonstrate that coronary arteries abundantly express TACE and have significant TACE activity (Fig. 4). Importantly, we found that in aging TACE expression and activity is unchanged (Fig. 4, A and B), whereas expression of TNF is substantially upregulated. Thus we hypothesize that preserved TACE activity in aging is an important permissive factor that likely contributes to increased levels of bioactive TNF in the aged vascular wall. This view is also in line with recent observations showing increased serum levels of TNF in aged experimental animals (25) and elderly patients (20).
Increased vascular tissue levels of TNF likely contribute to the enhanced endothelial apoptosis in aged coronary arteries, because TNF blocking antibody significantly decreased apoptotic cell death in these vessels (Fig. 5A). Furthermore, exogenous TNF significantly enhanced apoptosis in the endothelium of coronary arteries of young and aged rats (Fig. 5, B and C) and in cultured rat coronary endothelial cells (Fig. 5D). These findings, taken together with results of previous studies, suggest that coronary endothelial cells are especially vulnerable to a proinflammatory microenvironment (6, 16). Age-related upregulation of TNF and increased sensitivity toward TNF-induced apoptosis were also reported in lymphocytes of aged humans (1). Moreover, decreased rate of apoptosis in various organs of aged rats due to caloric restriction (2), the only known procedure that increases maximum life span, is associated with a reduced TNF production (25).
Recent studies suggest that the sensitivity of endothelial cells to apoptosis is regulated in part by NO (13), which can inhibit various steps of TNF-induced apoptosis signaling via modification of proteins (13) and can induce telomerase activity (29). These effects of NO qualify it as an important anti-apoptotic and anti-aging factor that contributes to the maintenance of a youthful vascular phenotype. Indeed, pharmacological inhibition of NO synthesis in young coronary arteries substantially increased apoptotic cell death and potentiated the proapoptotic effect of TNF (Fig. 6A). Also, TNF-induced apoptosis in young coronary arteries was attenuated by an exogenous NO donor (Fig. 6B). Previously we demonstrated that bioavailability of NO is significantly decreased in aged coronary arteries due to an age-dependent decrease in eNOS expression (7) and an increase in superoxide production resulting in enhanced peroxynitrite formation (7). In addition, Akt-dependent eNOS activation may also decrease in aging (13). Because apoptotic cell death in aged coronary arteries in culture could be reduced by an exogenous NO donor, but inhibition of endogenous NO synthesis did not further increase apoptotic cell death (Fig. 5A), it is likely that a decreased bioavailability of NO in these vessels promotes apoptosis and potentiates the apoptotic effect of increased levels of TNF. This idea is supported by the findings that genetic lack of NO resulted in a substantially increased apoptosis in vessels of aged male eNOS knockout mice (unpublished observation) and promoted apoptosis in cultured endothelial cells (13). In senescent endothelial cells in culture there is also a downregulation of eNOS and the eNOS activator Akt, associated with an increased sensitivity toward TNF-induced apoptosis (13).
The mechanisms by which TNF induces apoptosis include binding of TNF to the death receptor TNFR1 and activation of a death-inducing signaling complex via the receptor death domain (6). Because administration of TNF activated caspase 9 both in young coronary arteries (Fig. 7A) and in cultured endothelial cells (Fig. 7B), it is logical to hypothesize that the increased tissue TNF levels contribute to increased caspase 9 activation in aged coronary arteries. Caspase 9 is involved in the mitochondrial proapoptotic pathway, and it can be assumed that its upregulation may enhance cellular sensitivity toward apoptotic stimuli. Indeed, downregulation of caspase 9 in CAEC (Fig. 7C) resulted in partial protection of these cells against TNF-induced apoptosis (Fig. 7D). Our results are in line with the findings of McDonnell et al. (17) showing TNF-induced early processing of caspase 9 and delaying the progression of apoptosis by a caspase-9-specific inhibitor. Importantly, a recent study found that caloric restriction, which decreases apoptosis in the heart of aged mice (15), downregulates the expression of caspase 9 in addition to TNF (25). It is likely that NO inhibits cellular apoptotic pathways downstream of caspase 9 (23), because administration of L-NAME or SNAP did not affect TNF-induced caspase 9 activity (Fig. 7A).
On the basis of the aforementioned findings, we propose (Fig. 7E) that aging alters gene expression in coronary arteries, resulting in upregulation of TNF and caspase 9 and decreased bioavailability of NO. These alterations promote endothelial apoptosis, which is likely to contribute to coronary arterial endothelial dysfunction and the development of ischemic heart disease in the elderly.
|
GRANTS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONGRANTSREFERENCES |
|---|
|
FOOTNOTES |
|---|
Address for reprint requests and other correspondence: G. Kaley, Dept. of Physiology, New York Medical College, Valhalla, NY 10595 (E-mail: gabor_kaley{at}nymc.edu).
10.1152/physiolgenomics.00136.2003.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONGRANTSREFERENCES |
|---|
This article has been cited by other articles:
|
|
 |
|
  N. Labinskyy, P. Mukhopadhyay, J. Toth, G. Szalai, M. Veres, G. Losonczy, J. T. Pinto, P. Pacher, P. Ballabh, A. Podlutsky, et al. Longevity is associated with increased vascular resistance to high glucose-induced oxidative stress and inflammatory gene expression in Peromyscus leucopus Am J Physiol Heart Circ Physiol, April 1, 2009; 296(4): H946 - H956. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Csiszar, N. Labinskyy, V. Perez, F. A. Recchia, A. Podlutsky, P. Mukhopadhyay, G. Losonczy, P. Pacher, S. N. Austad, A. Bartke, et al. Endothelial function and vascular oxidative stress in long-lived GH/IGF-deficient Ames dwarf mice Am J Physiol Heart Circ Physiol, November 1, 2008; 295(5): H1882 - H1894. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Csiszar, M. Wang, E. G. Lakatta, and Z. Ungvari Inflammation and endothelial dysfunction during aging: role of NF-{kappa}B J Appl Physiol, October 1, 2008; 105(4): 1333 - 1341. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Csiszar, N. Labinskyy, H. Jo, P. Ballabh, and Z. Ungvari Differential proinflammatory and prooxidant effects of bone morphogenetic protein-4 in coronary and pulmonary arterial endothelial cells Am J Physiol Heart Circ Physiol, August 1, 2008; 295(2): H569 - H577. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Csiszar and Z. Ungvari Endothelial dysfunction and vascular inflammation in Type 2 diabetes: interaction of AGE/RAGE and TNF-{alpha} signaling Am J Physiol Heart Circ Physiol, August 1, 2008; 295(2): H475 - H476. [Full Text] [PDF]
|
|
|
|
|
|
A. Csiszar, N. Labinskyy, A. Podlutsky, P. M. Kaminski, M. S. Wolin, C. Zhang, P. Mukhopadhyay, P. Pacher, F. Hu, R. de Cabo, et al. Vasoprotective effects of resveratrol and SIRT1: attenuation of cigarette smoke-induced oxidative stress and proinflammatory phenotypic alterations Am J Physiol Heart Circ Physiol, June 1, 2008; 294(6): H2721 - H2735. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. Ungvari, N. Labinskyy, S. Gupte, P. N. Chander, J. G. Edwards, and A. Csiszar Dysregulation of mitochondrial biogenesis in vascular endothelial and smooth muscle cells of aged rats Am J Physiol Heart Circ Physiol, May 1, 2008; 294(5): H2121 - H2128. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. Ungvari, C. Parrado-Fernandez, A. Csiszar, and R. de Cabo Mechanisms Underlying Caloric Restriction and Lifespan Regulation: Implications for Vascular Aging Circ. Res., March 14, 2008; 102(5): 519 - 528. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Reungjui, C. A. Roncal, W. Sato, O. Y. Glushakova, B. P. Croker, S.-i. Suga, X. Ouyang, K. Tungsanga, T. Nakagawa, R. J. Johnson, et al. Hypokalemic Nephropathy is Associated with Impaired Angiogenesis J. Am. Soc. Nephrol., January 1, 2008; 19(1): 125 - 134. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Rajashekhar, M. Grow, A. Willuweit, C. E. Patterson, and M. Clauss Divergent and convergent effects on gene expression and function in acute versus chronic endothelial activation Physiol Genomics, September 11, 2007; 31(1): 104 - 113. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Csiszar, N. Labinskyy, Z. Orosz, Z. Xiangmin, R. Buffenstein, and Z. Ungvari Vascular aging in the longest-living rodent, the naked mole rat Am J Physiol Heart Circ Physiol, August 1, 2007; 293(2): H919 - H927. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. Ungvari, Z. Orosz, N. Labinskyy, A. Rivera, Z. Xiangmin, K. Smith, and A. Csiszar Increased mitochondrial H2O2 production promotes endothelial NF-{kappa}B activation in aged rat arteries Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H37 - H47. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. Ungvari, Z. Orosz, A. Rivera, N. Labinskyy, Z. Xiangmin, S. Olson, A. Podlutsky, and A. Csiszar Resveratrol increases vascular oxidative stress resistance Am J Physiol Heart Circ Physiol, May 1, 2007; 292(5): H2417 - H2424. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. Orosz, A. Csiszar, N. Labinskyy, K. Smith, P. M. Kaminski, P. Ferdinandy, M. S. Wolin, A. Rivera, and Z. Ungvari Cigarette smoke-induced proinflammatory alterations in the endothelial phenotype: role of NAD(P)H oxidase activation Am J Physiol Heart Circ Physiol, January 1, 2007; 292(1): H130 - H139. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Csiszar, N. Labinskyy, K. Smith, A. Rivera, Z. Orosz, and Z. Ungvari Vasculoprotective Effects of Anti-Tumor Necrosis Factor-{alpha} Treatment in Aging Am. J. Pathol., January 1, 2007; 170(1): 388 - 698. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Labinskyy, A. Csiszar, Z. Orosz, K. Smith, A. Rivera, R. Buffenstein, and Z. Ungvari Comparison of endothelial function, O2-{middle dot} and H2O2 production, and vascular oxidative stress resistance between the longest-living rodent, the naked mole rat, and mice. Am J Physiol Heart Circ Physiol, December 1, 2006; 291(6): H2698 - H2704. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Csiszar, K. Smith, N. Labinskyy, Z. Orosz, A. Rivera, and Z. Ungvari Resveratrol attenuates TNF-{alpha}-induced activation of coronary arterial endothelial cells: role of NF-{kappa}B inhibition. Am J Physiol Heart Circ Physiol, October 1, 2006; 291(4): H1694 - H1699. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. A. Lemarie, P.-L. Tharaux, B. Esposito, A. Tedgui, and S. Lehoux Transforming Growth Factor-{alpha} Mediates Nuclear Factor {kappa}B Activation in Strained Arteries Circ. Res., August 18, 2006; 99(4): 434 - 441. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. Kovacs, J. Toth, J. Tarjan, and A. Koller Correlation of flow mediated dilation with inflammatory markers in patients with impaired cardiac function. Beneficial effects of inhibition of ACE Eur J Heart Fail, August 1, 2006; 8(5): 451 - 459. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A.P.J.J. Bijnens, E. Lutgens, T. Ayoubi, J. Kuiper, A.J. Horrevoets, and M.J.A.P. Daemen Genome-Wide Expression Studies of Atherosclerosis: Critical Issues in Methodology, Analysis, Interpretation of Transcriptomics Data Arterioscler Thromb Vasc Biol, June 1, 2006; 26(6): 1226 - 1235. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Csiszar, M. Ahmad, K. E. Smith, N. Labinskyy, Q. Gao, G. Kaley, J. G. Edwards, M. S. Wolin, and Z. Ungvari Bone Morphogenetic Protein-2 Induces Proinflammatory Endothelial Phenotype Am. J. Pathol., February 1, 2006; 168(2): 629 - 638. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Zheng, A. Chin, I. Duignan, K.-H. Won, M. K. Hong, and J. M. Edelberg Growth factor-mediated reversal of senescent dysfunction of ischemia-induced cardioprotection Am J Physiol Heart Circ Physiol, February 1, 2006; 290(2): H525 - H530. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Csiszar, K. E. Smith, A. Koller, G. Kaley, J. G. Edwards, and Z. Ungvari Regulation of Bone Morphogenetic Protein-2 Expression in Endothelial Cells: Role of Nuclear Factor-{kappa}B Activation by Tumor Necrosis Factor-{alpha}, H2O2, and High Intravascular Pressure Circulation, May 10, 2005; 111(18): 2364 - 2372. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P.-Y. Chang, T.-L. Wu, K.-C. Tsao, C.-C. Li, C.-F. Sun, and J. T. Wu Microplate ELISAs for Soluble VCAM-1 and ICAM-1 Ann. Clin. Lab. Sci., January 1, 2005; 35(3): 312 - 317. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
