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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

To the Editor:

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 studies^3–5 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.

	Acknowledgments

 
Source of Funding

This work was supported by an educational grant from AstraZeneca (Belgium).

Disclosures

None.

	References

Top References

 
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.[Abstract/Free Full Text]

2. Bouzeghrane F, Thibault G. Is angiotensin II a proliferative factor of cardiac fibroblasts? Cardiovasc Res. 2002; 53: 304–312.[Abstract/Free Full Text]

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]

This article has been cited by other articles:

				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]

This Article Extract Full Text (PDF) All Versions of this Article: 51/6/e50    most recent HYPERTENSIONAHA.108.112649v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lijnen, P. Search for Related Content PubMed PubMed Citation Articles by Lijnen, P. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Related Collections Other hypertension