Journal of Lipid Research, Vol. 42, 1325-1330, August 2001
Copyright © 2001 by Lipid Research, Inc.
Long-chain fatty acids modify hypertrophic responses of cultured primary neonatal cardiomyocytes
Ahmad Zahabia and
Christian F. Descheppera
a Experimental Cardiovascular Biology Research Unit and CIHR Multidisciplinary Research Group on Hypertension, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada H2W 1R7
Correspondence to:
Christian F. Deschepper, To whom correspondence should be addressed., deschec{at}ircm.qc.ca (E-mail)
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ABSTRACT |
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In vivo, the normal heart obtains at least 60% of its energy from lipids and the remainder from glucose. Several lines of evidence indicate that an increase in the utilization of glucose [at the expense of fatty acids (FA)] may play a role in the genesis of hypertrophy. Primary cultures of neonatal cardiomyocytes have been used extensively to study the phenotype of these cells as well as their responses to hormonal hypertrophic agents. Unfortunately, such cultures are most typically cultured in glucose-rich FA-free media, and thus might be hypertrophied to start with. We therefore tested the effects of FA-albumin complexes on three different surrogate end points of hypertrophy of cardiomyocytes. Oleate-albumin complexes decreased the baseline values of all three variables, and increased the relative response of these variables to administration of norepinephrine. Oleate:palmitate-albumin complexes also affected all three variables and their responses to norepinephrine, but the effects differed somewhat from that of oleate-albumin complexes.
Our results suggest that addition of long-chain FA, by providing conditions that more closely resemble physiological situations, may optimize the expression of hypertrophic responses in such cells. However, the differences between the effects of oleate and oleate:palmitate also suggest that the precise composition of FA may affect the phenotype of cardiomyocytes and how these cells respond to hypertrophic agents. — Zahabi, A., and C. F. Deschepper. Long-chain fatty acids modify hypertrophic responses of cultured primary neonatal cardiomyocytes. J. Lipid Res. 2001. 42: 1325;–1330.
Supplementary key words:
primary cultures, hypertrophy, oleic acid, glucose, metabolism, palmitic acid
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INTRODUCTION |
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Normal cardiac function depends on an adequate delivery of oxygen and fuels in order to meet the energy demands of the myocardium (1). In vivo, the normal heart obtains at least 60% of its energy from lipids (mostly long-chain fatty acids), and the remainder from glucose (1) (2) (3). Although the rate of utilization of glucose is usually inversely proportional to that of fatty acids (FA) (3), several lines of evidence indicate that an increase in the rate of utilization of glucose (at the expense of FA) may play a role in the genesis of hypertrophy. Indeed, it has been reported that glucose uptake and ventricular concentration of the mRNA transcripts of glycolytic enzymes are increased in several experimental models of ventricular hypertrophy, concomitantly with a decrease in FA uptake and in the ventricular concentration of mRNA transcripts of lipolytic enzymes (4) (5) (6) (7) (8) (9). In addition, pharmacological treatments that increase cardiac glucose utilization (along with a decrease in FA utilization) have been found to cause left ventricular hypertrophy in animal models (10) (11). Finally, inborn errors in FA metabolism have been shown to be associated with the development of cardiac hypertrophy (12).
Primary cultures of rat neonatal cardiomyocytes constitute tools that have been used widely as a means to elucidate the pathways and mechanisms that underlie the development of ventricular hypertrophy (13). Despite the inevitable shortcomings of the model, one of its strengths is that many of the molecules found to induce or modulate hypertrophy in vitro have also been found to be effective in vivo (13). However, most primary cultures of cardiomyocytes used previously have typically been maintained in glucose-rich medium that contained either no or subphysiologic amounts of FA. Given the possible role of glucose uptake in cardiac hypertrophy, cells cultured in such fashion might in fact already display some features of hypertrophy, or show blunted responses to additional hypertrophic stimuli. To test this hypothesis, we verified whether addition of complexes of albumin and FA to the culture medium of primary neonatal cardiomyocytes would affect the responses of cells to hypertrophic agents. Three different end points were used to evaluate hypertrophy responses, that is, de novo protein synthesis, cell surface, and secretion of atrial natriuretic factor (ANF).
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MATERIALS AND METHODS |
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Cell culture
The method for preparing ventricular cardiomyocytes from 3-day-old Sprague-Dawley rats was adapted from previously published protocols (14) (15). Briefly, after removing the hearts from 3-day-old decapitated pups, the ventricles were separated from the atria, rinsed with MEM-Joklik medium (GIBCO-BRL, Burlington, ON, Canada), and minced into 1-mm-wide pieces with scalpel blades. Sedimented tissues were then resuspended in a solution of MEM-Joklik containing collagenase type II (2 mg/ml; Worthington, Freehold, NJ). After shaking the tissues for 20 min at 37°C, dislodged cells were recovered by centrifugation, and the procedure was repeated once. The products of both digestions were pooled and resuspended in DMEM containing 10% FBS, and noncardiomyocytes were selected by two cycles of 30 min of preplating at 37°C in tissue culture dishes. Nonadherent cardiomyocytes were then plated on 6- or 24-well Cell-Plus plates (Sarstedt, St. Laurent, QC, Canada) for primary cultures at a density of 15,000;–20,000 cells/cm2. After being maintained overnight in DMEM-F12 (GIBCO-BRL) containing D-glucose (17.5 mM) and supplemented with 10% FBS, penicillin, streptomycin, and amphotericin B (Fungizone), the cells were changed to serum-free medium (SFM) containing DMEM-F12 supplemented with insulin (5 µg/ml), transferrin (5 µg/ml), and selenium (5 ng/ml) (Sigma, St. Louis, MO), 20 mM HEPES, bovine apotransferrin (2.5 µg/ml; GIBCO-BRL), penicillin, streptomycin, and Fungizone. For preparation of FA-free medium, FA-free BSA (Roche Diagnostic, Laval, QC, Canada) was added to the SFM at a concentration that matched that of FA-supplemented medium (either 75, 150, or 300 mM, thus corresponding to 5, 10, or 20 mg/ml). For preparation of FA-enriched medium, FA-BSA complexes were prepared according to published protocols (16) (17). Thus, either 5, 10, or 20 mg of FA [either oleic acid-free acid or a 1:1 mixture of palmitic:oleic acid free acid (Sigma)] was added to 2 ml of H2O, and dissolved by adding 30 µl of 1 N NaOH and heating briefly at 70°C with agitation. Eight milliliters of a solution of FA-free BSA (either 62.5, 125, or 250 mg/ml) was then added dropwise to the dissolved FA. The whole solution was sterile filtered to yield 10x stock solutions containing either 2, 4, or 8 mM FA complexed in an approximate 3:1 ratio with BSA (either 0.75, 1.5, or 3 mM). When dissolved 1:10 in culture medium, the final concentration of complexed FA was within the range of low physiological circulating levels (1) (18).
ANF radioimmunoassay
Culture medium was collected on the last day of the culture, and 20-µl aliquots were used to assay the concentration of ANF in the medium, using the same reagents and procedures as described previously (19).
Lactic dehydrogenase (LDH) measurement
After overnight exposure to various FA treatments, the culture medium was collected to measure LDH activity, as described previously (20). The reagents used were as follows. Solution 1 contained lactate at 36 mg/ml in 10 mM Tris, pH 8.5; solution 2 contained 2-(p-indophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride dissolved in dimethyl sulfoxide (20 mg/ml) to prepare a 10x stock solution, which was further diluted with PBS to make a 1x solution; solution 3 contained NAD+ (3 mg/ml), diaphorase (13.5 U/ml), BSA (0.3 mg/ml), and sucrose (12 mg/ml), all dissolved in PBS; solution 4 contained oxamate (16.6 mg/ml) in PBS. Twenty microliters of solution 1, 2, and 3 was mixed with aliquots of 150 µl of culture medium in the wells of 96-well plates, and incubated for 20 min at room temperature. In addition to experimental samples, some wells contained doses of type VIII LDH from chicken heart (Sigma) ranging from 10 to 300 units/well in order to construct a standard curve. At the end of the incubation, the reactions was then stopped by the addition of 20 µl of solution 4, and absorbance was read in a 96-well spectrophotometer, using an emission wavelength of 490 nm.
Histochemical staining
After completion of designated treatments, cells seeded in six-well culture plates were washed in PBS, fixed for 5 min in an acetone;–methanol 1:1 (v/v) mixture, and washed again with PBS. The primary antibody (monoclonal anti-
-sarcomeric actin clone 5C5; Sigma) was diluted 1:500 in PBS and applied to the cells for 1 h at room temperature, and the cells were then washed with PBS. The secondary antibody [anti-mouse polyvalent immunoglobulins, conjugated with fluorescein isothiocyanate (FITC); Sigma] was diluted 1:200 and applied for 1 h at room temperature. After PBS washing, the cell nuclei were counterstained for 5 min with Hoechst No. 33,342 (10 µg/ml). Analysis of the cells was done by fluorescence microscopy, using a x20 objective.
Experimental designs
(-)-Norepinephrine (NE; Sigma) was added to the medium at 10-4 M when the cultures were switched from serum-containing medium to SFM. All incubations were stopped 48 h after the medium switch, that is, 3 days after the initial day of plating.
De novo protein synthesis
Incorporation of L-[2,3,4,5,6-3H]phenylalanine ([3H]Phe, 118 Ci/mmol; Amersham Pharmacia, Baie d'Urfé, QC, Canada) into newly synthesized proteins was performed as described previously (21). One day after plating, the cells were changed to SFM (±experimental agents) supplemented with labeled amino acid (0.5 µCi/ml). After 48 h of being maintained at 37°C with 5% CO2 in a humidified atmosphere, the cells were rinsed with PBS, treated with 10% TCA at 0°C for 1 h, rinsed three times with cold TCA, and dissolved with 500 µl of 1% SDS. Four hundred microliters of that sample was added to 5 ml of ScintiSafe Econo 1 (Fisher Scientific, Nepean, ON, Canada) for scintillation counting. Fifty microliters of sample was used to measure DNA by Hoechst fluorescence with a Sequoia-Turner (Mountain View, CA) 450 fluorometer, using excitation and emission wavelengths of 360 and 450 nm, respectively. Final results were expressed as counts per minutes per microgram of DNA. Averages of 12 wells were used in each experimental group. In preliminary experiments, we verified that [3H]Phe incorporation increased linearly in cells collected 12, 24, 36, and 48 h after addition of radioactivity to the culture medium, regardless of the culture conditions or treatments applied to the cells.
Cell surface measurements
Cells cultured in six-well plates were fixed for 10 min with 4% paraformaldehyde in PBS, and then stained with Giemsa. The cells were examined with an inverted microscope connected to a video camera that allowed capture of the images as electronic files. Using Northern Eclipse v. 5.0 analysis software (Empix Imaging, Mississauga, ON, Canada), the surface of each cell was calculated on the basis of its hand-defined contour. Averages of 36 cells were measured in each experimental group. Final results were expressed as micrometers squared.
Statistics
Comparisons between groups with or without NE were done by Student's t-tests. Comparisons between baseline values of cells cultured under three different conditions were done by one-way analysis of variance followed by Fisher's LSD post-hoc tests. Comparisons of the values of relative NE-induced increases between cells cultured with or without FA were performed by nonparametric Mann-Whitney U-tests.
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RESULTS |
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Neonatal cardiomyocytes were cultured for 48 h in the presence of three different concentrations of BSA, either uncomplexed or complexed 1:3 with FA (either oleate alone or a 1:1 oleate:palmitate mixture). We assessed the effect of each treatment on three different hypertrophy end points, that is, de novo protein synthesis, cell surface area, and secretion of ANF ( Fig 1). FA-free BSA by itself had a slight effect on baseline values of all three variables, as it decreased them in a dose-related fashion. However, at all three doses, the baseline values of each variable were decreased even further when BSA was complexed to oleate. Whereas oleate-BSA complexes affected the baseline values of all variables in a consistent and coordinated fashion, the effects of the oleate:palmitate mixture were more variable. Indeed, all three doses of oleate:palmitate increased the baseline values of [3H]Phe incorporation, and the two lowest doses increased the baseline levels of ANF secretion. In contrast, and similarly to oleate, all three doses of oleate:palmitate decreased the baseline values of cell surface area.
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Figure 1.
Effects of 10-4 M NE on [3H]Phe incorporation, ANF secretion, and cell surface area of cultured cardiomyocytes maintained with different concentrations and compositions of FA. Open columns, control; solid columns, 10-4 M NE. All results represent means (n = 30;–36) ± SEM, and represent pooled values from three different experiments. The respective concentration of either BSA or FA in each group is indicated at the top. Values from the NE-treated group were significantly higher than those of the nontreated group (no significance symbol has been represented), with only one exception (cell surface area in the BSA 75 µM/no FA group). For each assay, a dotted line has been drawn at the level of the baseline values within the group with the lowest concentration of additives, for comparison purposes. *P < 0.05 as compared with baseline values in the group with no FA, as determined by Fisher's LSD post-hoc test. CTL, Control; Ol., oleate; O + P, 1:1 oleate:palmitate; NE, norepinephrine; ANF, atrial natriuretic factor.
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NE increased the mean value of each variable regardless of the culture condition, and the difference was statistically significant in virtually all cases (Fig 1). In addition to baseline values, the absolute values reached by each variable after NE treatment was also affected to different extents by culture conditions. Consequently, the relative NE-induced changes (defined as the percentage of the NE-induced value over baseline value) varied according to culture conditions ( Table 1). Again, the effect of oleate-BSA was consistent across experimental groups, as all three doses of oleate-BSA complexes decreased the baseline values of all three experimental variables when compared with BSA with no FA. Like oleate, oleate:palmitate (at medium and high concentrations) also increased the relative NE-induced augmentation in de novo protein synthesis and cell surface area. In contrast, oleate:palmitate (at low or medium concentrations) blunted the relative NE-induced augmentation in ANF secretion.
Fig 2 shows representative cardiomyocytes belonging to each culture condition and stained with an anti--sarcomeric actin antibody. The effect of each treatment on cell surface is readily apparent. Moreover, we measured LDH activity in cell culture supernatants. We found no differences in the levels of LDH activity in the media of cells from each culture condition, which argues against any deleterious effect of FA supplements on cardiomyocytes.
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Figure 2.
Morphological appearance of cardiomyocytes cultured with BSA alone (150 µM), or with BSA complexed to either oleate or oleate:palmitate (0.4 mM), either untreated (control) or treated with 10-4 M NE (norepi). All cells have been stained with an anti--sarcomeric actin antibody.
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DISCUSSION |
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Several lines of evidence indicate that increased glucose utilization and decreased FA may play a role in the genesis of hypertrophy, and vice versa (4) (5) (6) (7) (8) (9) (10) (11). However, most investigators who have studied the effects of hypertrophic agents in vitro have cultured primary cardiomyocytes in glucose-rich media devoid of FA. It is therefore possible that cardiomyocytes cultured under such conditions display some features of hypertrophy under basal conditions, concomitantly with blunted responses to additional hypertrophic stimuli. In some of the few cases in which FA have been added to the culture medium of cardiomyocytes, the concentration of FA was unfortunately much lower than that of physiological circulating levels. For instance, Shields et al. (15) have used a mixture of linoleic acid (0.1 µg/ml) and docosahexaenoic acid (0.5 µg/ml) in the presence of BSA, whereas Mohamed et al. (22) advocated the use of complexes of palmitate (0.1 µM) and BSA. In these two cases, the final concentration of FA in the medium was 160 and 40 times lower, respectively, than the concentrations used in the present study. In some other cases, neonatal cardiomyocytes have been cultured in the presence of FA-BSA complexes at concentrations similar to that used in the present study, but hypertrophy responses were not the primary focus of these particular studies (23) (24) (25). Nonetheless, chronic palmitate:oleate-BSA has been shown to induce many phenotypic changes in cardiomyocytes, including an increase in the rate of FA oxidation, an increase in the mRNA concentration of several genes involved in FA metabolism, and a decrease in the mRNA concentration of several genes involved in glucose metabolism (23).
Our study differed from previous investigations in that we focused on how two different types of FA-BSA complexes (at three concentrations within the range of low physiological circulating levels) affect hypertrophic responses of cultured cardiomyocytes. To date, a variety of surrogate end points have been used to quantitate the effects of hypertrophic responses in vitro (26). Because it is not entirely clear which particular end point relates most closely to cardiac hypertrophy in vivo, we used three different assays, that is, de novo protein synthesis, cell surface, and ANF secretion. In rat blood, palmitic and oleic acids have been reported to constitute the most abundant fatty-acyl moieties (27). However, it has also been shown that palmitate-BSA complexes induced apoptotic cell death in ventricular cardiomyocytes, whereas complexes using either oleic acid or a 1:1 mixture of oleic and palmitate acid were well tolerated by the cells (24) (25). Consequently, we used oleic acid for our experiments, either alone or in a 1:1 mixture with palmitic acid. Of note, other studies that had added FA to culture media also used carnitine, as it is an essential component for FA oxidation (18) (24). In preliminary experiments, we had compared the effects of culture media with or without carnitine supplements (50 µM). Because we observed no consistent effect of the supplement on any of the variables we measured, this reagent was not used in subsequent experiments. However, our experiments were all short term, as they were stopped only 3 days after the initial day of plating. Because heart cells in vivo lack the ability to synthesize the essential element carnitine (28) (29), it is possible that experiments maintaining cardiomyocytes for longer periods may require supplements of carnitine.
All three doses of oleate-BSA complexes decreased the baseline values of all three variables when compared with cells maintained in BSA with no FA, and therefore influenced all three end points of hypertrophy in a coherent and consistent manner. There appeared to be no deleterious effect of FA on cell viability, because FA caused no increase in LDH activity in the culture medium, and the cells remained able to mount a vigorous response to NE. Moreover, the decrease in baseline values had another consequence, as it increased the relative effect of NE when expressed as either fold increase or percentage change versus baseline. The importance of this point lies in the fact that the vast majority of studies looking at the effects of hypertrophic agents on cardiomyocytes (and in particular those studying transfected promoter activity) express data in this fashion (30) (31) (32). The effect of oleate on the relative NE-induced changes was not restricted to NE only, as we observed that the increase in de novo protein synthesis and cell surface area induced by two other hypertrophic treatments (10-7 M endothelin and 10-6 M angiotensin II) was also higher in oleate-containing medium than in medium without oleate (data not shown).
Oleate:palmitate-BSA complexes also affected hypertrophy end points, but differently than oleate-BSA. In contrast to oleate-BSA, oleate:palmitate-BSA (at most concentrations) increased the baseline levels of de novo protein synthesis and ANF secretion as compared with BSA with no FA. However (similarly to oleate-BSA), oleate:palmitate-BSA decreased the baseline values of cell surface areas at all concentrations tested. Oleate:palmitate-BSA also had distinct effects on the relative NE-induced changes. At medium and high concentrations, it increased the relative NE-induced augmentation in de novo protein synthesis and cell surface area. However, when used at low or medium concentrations, it blunted the relative NE-induced augmentation in ANF secretion. Such disparity of effects on different variables brings back the question of which variable represents the best surrogate end point of hypertrophy. The rate of protein synthesis per unit of DNA corresponds to the most conservative definition of hypertrophy, and has been considered as one of the most reliable end points (33). Likewise, cell surface area is a direct morphometric measurement that is affected by most hypertrophy-inducing agents (13). In comparison, ANF secretion represents a more indirect variable. It usually correlates well with hypertrophy (13) (34), but there are some cases in which the correlation no longer holds (35).
In conclusion, our results show that addition of long-chain FA to primary cultures of neonatal ventricular cardiomyocytes increases the relative effect of hypertrophic agents on de novo protein synthesis and cell surface area. Given the facts that FA represent the main source of energy of hearts in vivo, and that decreased FA utilization has been suggested to play a role in the genesis of hypertrophy, addition of long-chain FA to the culture medium of cardiomyocytes may provide culture conditions that more closely resemble physiological situations, and optimize hypertrophic responses in such cells. However, we also observed that oleate and oleate:palmitate affected cardiomyocytes differently, which suggests that the precise composition of FA may affect the phenotype of cardiomyocytes and how these cells respond to hypertrophic agents.
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FOOTNOTES |
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Abbreviations: ANF, atrial natriuretic factor; FA, fatty acids; NE, norepinephrine. 
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ACKNOWLEDGMENTS |
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This work was supported by grants MOP-14086 and MOP-36449 from the Medical Research Council of Canada (MRCC), by a grant from the Fondation des Maladies du Coeur du Québec to C.F.D., and by a grant from the CIHR/MRC to the Multidisciplinary Research Group on Hypertension. We thank T. L. Reudelhuber, P. Paradis, and G. Thibault for critically reading the manuscript.
Manuscript received October 4, 2000; and in revised form March 29, 2001
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REFERENCES |
|---|
- Van der Vusse, G. J., Glatz, J. F. C., Stam, H. C. G., Reneman, R. S. 1992. Fatty acid homeostasis in the normoxic and ischemic heart. Physiol. Rev. 72:881-940[Free Full Text].
- Lopaschuk, G., Belke, D. D., Gamble, J., Itoi, T., Schönekess, B. O. 1994. Regulation of fatty acid oxidation in the mammalian heart in health and disease. Biochim. Biophys. Acta. 1213:263-276[Medline].
- Depré, C., Rider, M. H., Hue, L. 1998. Mechanisms of control of heart glycolysis. Eur. J. Biochem. 258:277-290[Medline].
- Yonekura, Y., Brill, A. B., Som, P., Yamamoto, K., Srivastava, S. C., Iwai, J., Elmaleh, D. E., Livni, E., Strauss, H. W., Goodman, M. M., Knapp, F. F., Jr. 1985. Regional myocardial substrate uptake in hypertensive rats: a quantitative autoradiographic measurement. Science. 227:1494-1496[Abstract/Free Full Text].
- Kagaya, Y., Kanno, Y., Takeyama, D., Ishide, N., Maruyama, Y., Takahashi, T., Ido, T., Takishima, T. 1990. Effects of long-term pressure overload on regional myocardial glucose and free fatty acid uptake in rats: a quantitative autoradiographic study. Circulation. 81:1353-1361[Abstract/Free Full Text].
- Christie, M. E., Rodgers, R. L. 1994. Altered glucose and fatty acid oxidation in hearts of the spontaneously hypertensive rat. J. Mol. Cell. Cardiol. 26:1371-1375[Medline].
- Taegtmeyer, H., Overturf, M. L. 1988. Effects of moderate hypertension on cardiac function and metabolism in the rabbit. Hypertension. 11:416-426[Abstract/Free Full Text].
- Sack, M. N., Disch, D. L., Rockman, H. A., Kelly, D. P. 1997. A role for Sp and nuclear receptor transcription factors in a cardiac hypertrophy growth program. Proc. Natl. Acad. Sci. USA. 94:6438-6443[Abstract/Free Full Text].
- Depré, C., Shipley, G. L., Chen, W., Han, Q., Doenst, T., Moore, M. L., Stepkowski, S., Davies, P. J. A., Taegtmeyer, H. 1998. Unloaded heart in vivo replicates fetal gene expression of cardiac hypertrophy. Nat. Med. 4:1269-1275[Medline].
- Bressler, R., Gay, R., Copelan, J. G., Bahl, J. J., Bedotto, J., Goldman, S. 1989. Chronic inhibition of fatty acid oxidation: new model of diastolic dysfunction. Life Sci. 44:1897-1906[Medline].
- Rupp, H. E. V., Dhalla, N. S. 1992. Modification of subcellular organelles in pressure-overloaded heart by etoximir, a carnitine palmitoyltransferase I inhibitor. FASEB J. 6:2349-2353[Abstract].
- Kelly, D. P., Strauss, A. W. 1994. Inherited cardiomyopathies. N. Engl. J. Med. 330:913-919[Free Full Text].
- Chien, K. R., Knowlton, K. U., Zhu, H., Chien, S. 1991. Regulation of cardiac gene expression during myocardial growth and hypertrophy: molecular studies of an adaptative physiologic response. FASEB J. 5:3037-3046[Abstract].
- Argentin, S., Ardati, A., Tremblay, S., Lihrmann, I., Robitaille, L., Drouin, J., Nemer, M. 1994. Developmental stage-specific regulation of atrial natriuretic factor gene transcription in cardiac cells. Mol. Cell. Biol. 14:777-790[Abstract/Free Full Text].
- Shields, P. P., Dixon, J. E., Gembotski, C. C. 2000. The secretion of atrial natriuretic factor-(99;–126) by cultured cardiac myocytes is regulated by glucocorticoids. J. Biol. Chem. 263:12619-12628[Abstract/Free Full Text].
- Luiken, J. J. F. P., van Nieuwenhoven, F. A., America, G., Van der Vusse, G. J., Glatz, J. F. C. 1997. Uptake and metabolism of palmitate by isolated cardiac myocytes from adult rats: involvement of sarcolemmal proteins. J. Lipid Res. 38:745-758[Abstract].
- Brandt, J. M., Djouad, F., Kelly, D. P. 1998. Fatty acids activate transcription of the muscle carnitine palmitoyltransferase I gene in cardiac myocytes via the peroxisome proliferator-activated receptor . J. Biol. Chem. 273:23786-23792[Abstract/Free Full Text].
- Bolon, C., Gauthier, C., Simonnet, H. 1997. Glycolysis inhibition by palmitate in renal cels cultured in a two-chamber system. Am. J. Physiol. 273:C1732-C1738[Abstract/Free Full Text].
- Gutkowska, J., Genest, J., Thibault, G., Garcia, R., Larochelle, P., Cusson, J. R., Kuchel, O., Hamet, P., De Léan, A., Cantin, M. 1987. Circulating forms and radioimmunoassay of atrial natriuretic factor. Endocrinol. Metab. Clin. North Am. 16:183-198[Medline].
- Decker, T., Lohmann-Matthes, M. L. 1988. A quick and simple method for the quantitation of lactate dehydrogenase release in measurements of cellular cytotoxicity and tumor necrosis factor (TNF) activity. J. Immunol. Methods. 115:61-69[Medline].
- Simpson, P. C. 1985. Stimulation of hypertrophy of cultured neonatal rat heart cells through an 1-adrenergic receptor and induction of beating through an 1- and ß1-adrenergic receptor interaction. Circ. Res. 56:884-894[Abstract/Free Full Text].
- Mohamed, S. N. W., Holmes, R., Hartzell, C. R. 1983. A serum-free, chemically defined medium for function and growth of primary neonatal rat heart cell cultures. In Vitro. 19:471-478[Medline].
- van der Lee, K. A. J. M., Vork, M. M., De Vries, J. E., Willemsen, P. H. M., Glatz, J. F. C., Reneman, R. S., Van der Vusse, G. J., van Bilsen, M. 2000. Long-chain fatty acid-induced changes in gene expression in neonatal cardiac myocytes. J. Lipid Res. 41:41-47[Abstract/Free Full Text].
- van Bilsen, M., De Vries, J. E., Van der Vusse, G. J. 1997. Long-term effects of fatty acids on cell viability and gene expression of neonatal cardiac myocytes. Prostaglandins Leukot. Essent. Fatty Acids. 57:39-45[Medline].
- De Vries, J. E., Vork, M. M., Roemen, T. H. M., de Jong, Y. F., Cleutjens, J. P. M., Van der Vusse, G. J., van Bilsen, M. 1997. Saturated but not mono-unsaturated fatty acids induce apoptotic cell death in neonatal rat ventricular myocytes. J. Lipid Res. 38:1384-1394[Abstract].
- Sugden, P. H. 1999. Signaling in myocardial hypertrophy. Circ. Res. 84:633-646[Free Full Text].
- Van der Vusse, G. J., Roemen, T. H. M., Flameng, W., Renneman, R. S. 1983. Serum-myocardium gradients of non-esterified fatty acids in dog, rat and man. Biochim. Biophys. Acta. 752:361-370[Medline].
- Siliprandi, N., Ciman, M., Sartorelli, L. 1987. Myocardial carnitine transport. Basic Res. Cardiol. 82(Suppl. 1):53-62.
- Rebouche, C. J., Engel, A. G. 1980. Tissue distribution of carnitine biosynthetic enzymes in man. Biochim. Biophys. Acta. 630:22-29[Medline].
- Deng, X-F., Rokosh, D. G., Simpson, P. C. 2000. Autonomous and growth factor-induced hypertophy in cultued neonatal mouse cardiac myocytes. Comparison with rat. Circ. Res. 87:781-788[Abstract/Free Full Text].
- Ardati, A., Nemer, M. 1993. A nuclear pathway for 1-adrenergic receptor signaling in cardiac cells. EMBO J. 12:5131-5139[Medline].
- Gillespie-Brown, J., Fukker, S. J., Bogoyevitch, M. A., Cowley, S., Sugden, P. H. 1995. The mitogen-activated protein kinase kinase MEK1 stimulates a pattern of gene expression typical of the hypertrophic phenotype in rat ventricular cardiomyocytes. J. Biol. Chem. 270:28092-28096[Abstract/Free Full Text].
- Sugden, P. H., Clerk, A. 1998. Cellular mechanisms of cardiac hypertrophy. J. Mol. Med. 76:725-746[Medline].
- Ruskoaho, H. 1992. Atrial natriuretic peptide: synthesis, release, and metabolism. Pharmacol. Rev. 44:479-602[Medline].
- Masciotra, S., Picard, S., Deschepper, C. F. 1999. Cosegregation analysis in genetic crosses suggests a protective role for atrial natriuretic factor against ventricular hypertrophy. Circ. Res. 84:1453-1458[Abstract/Free Full Text].
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