Published online before print April 7, 2008, doi: 10.1161/HYPERTENSIONAHA.108.112649
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(Hypertension. 2008;51:e50.)
© 2008 American Heart Association, Inc.
Letters to the Editor |
Angiotensin II–Induced Proliferation of Neonatal and Adult Rat Cardiac Fibroblasts
Hypertension and Cardiovascular Rehabilitation Unit, Department of Cardiovascular Diseases, Katholieke Universiteit Leuven (KULeuven), Leuven, Belgium
Olson et al1 reported that stimulation of adult rat cardiac fibroblasts with angiotensin II (Ang II) resulted in a significant increase in 3H-thymidine incorporation over basal. Ang II indeed stimulated the proliferation of neonatal rat cardiac fibroblasts.2 However, discordant findings are reported on the in vitro effect of Ang II on the proliferation of cardiac fibroblasts of adult rats. Some studies3–5 could not detect any increase in proliferation, whereas others3 detected an increase in the proliferation of adult rat cardiac fibroblasts. It seems that the cell density greatly affected the proliferative response of adult fibroblasts to Ang II. This was nicely demonstrated by Simm and Diez3; confluent cultures (above 1x105 cells per cm2) of rat adult cardiac fibroblasts did not respond at all to Ang II, whereas proliferation occurred at lower density (below 2x104 cells per cm2). This increased proliferation was only seen after at least 40 hours of incubation and could be completely blocked by the addition of antiplatelet-derived growth factor-AA. The Ang II–induced cell proliferation of adult rat cardiac fibroblasts could be attributed to cell density-dependent expression of platelet-derived growth factor-AA.3 Cell-cell contact inhibition in high density cultures may account for the failure to induce response.
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Acknowledgments |
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Source of Funding
This work was supported by an educational grant from AstraZeneca (Belgium).
Disclosures
None.
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References |
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 Top References |
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1. Olson ER, Shamhart PE, Naugle JE, Meszaros JG. Angiotensin II-induced extracellular signal-regulated kinase
activation is mediated by protein kinase C
and intracellular calcium in adult rat cardiac fibroblasts. Hypertension. 2008; 51: 704–711.2. Bouzeghrane F, Thibault G. Is angiotensin II a proliferative factor of cardiac fibroblasts? Cardiovasc Res. 2002; 53: 304–312.
3. Simm A, Diez C. Density dependent expression of PDGF-A modulates the angiotensin II dependent proliferation of rat cardiac fibroblasts. Basic Res Cardiol. 1999; 94: 464–471.[CrossRef][Medline] [Order article via Infotrieve]
4. Brilla CG, Zhou G, Matsubara L, Weber KT. Collagen metabolism in cultured adult rat cardiac fibroblasts: response to angiotensin II and aldosterone. J Mol Cell Cardiol. 1994; 26: 809–820.[CrossRef][Medline] [Order article via Infotrieve]
5. Lee Aa, Dilmann WH, McCulloch AD, Villareal FJ. Angiotensin II stimulates the autocrine production of transforming growth factor-β1 in adult rat cardiac fibroblasts. J Mol Cell Cardiol. 1995; 27: 2347–2357.[CrossRef][Medline] [Order article via Infotrieve]
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  J. G. Meszaros Response to Angiotensin II-Induced Proliferation of Neonatal and Adult Rat Cardiac Fibroblasts Hypertension, June 1, 2008; 51(6): e51 - e51. [Full Text] [PDF]
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