EXTENDED REPORTS

Reduced circulating levels of angiotensin-(1–7) in systemic sclerosis: a new pathway in the dysregulation of endothelial-dependent vascular tone control

Alberto Pignone¹, Angela Del Rosso¹, K Bridget Brosnihan², Federico Perfetto¹, Riccardo Livi¹, Ginevra Fiori¹, Serena Guiducci¹, Marina Cinelli¹, Veronica Rogai¹, Alessio Tempestini¹, Francesca Bartoli¹, Sergio Generini¹, Carlos M Ferrario², Marco Matucci Cerinic¹

¹ Department of Medicine and Surgery, Division of Medicine I and II and Rheumatology, Villa Monna Tessa, University of Florence, Florence, Italy
² Hypertension and Vascular Disease Center, Wake Forest University School of Medicine, Winston Salem, NC 27157, USA

A Del Rosso, Department of Medicine and Surgery, Section of Medicine and Rheumatology, University of Florence, viale G. Pieraccini 18, 50134, Florence, Italy; a.delrosso{at}alice.it

Objective: Systemic sclerosis (SSc) impairs endothelium-dependent vasodilatation. Among angiotensin I (Ang I)-derived compounds, vasoconstrictor angiotensin II (Ang II) and vasodilator angiotensin-(1–7) (Ang-(1–7)), cleaved from ACE and neutral endopeptidase (NEP) 24.11, respectively, play an important role in vascular tone regulation. Ang-(1–7) may act independently or by activating other vasodilating molecules, such as nitric oxide (NO) or prostaglandin I2 (PGI2). Our aim was to assess, in patients with SSc, circulating levels of Ang I, Ang II and Ang-(1–7), with their metabolising enzymes ACE and NEP, and levels of NO and PGI2, and to correlate them to the main characteristics of SSc.

Methods: Levels of Ang I, Ang II, Ang-(1–7), NEP, ACE, NO and PGI2 were measured in 32 patients with SSc, who were also assessed for humoral and clinical characteristics, and 55 controls.

Results: Plasma Ang I, Ang II and Ang-(1–7) levels were lower in patients with SSc than in controls (p<0.001in all cases). When Ang II and Ang-(1–7) levels were expressed as a function of the available Ang I, lower Ang-(1–7) levels in patients with SSc than in controls were confirmed (p<0.001), while no difference was found for Ang II levels. In patients with SSc, the Ang II/Ang-(1–7) ratio indicated a prevalence of Ang II over Ang-(1–7), while in controls Ang-(1–7) was prevalent (p<0.001). Levels of ACE, NEP, NO and PGI2 were lower in patients with SSc than in controls (p<0.05 in all cases).

Conclusion: In patients with SSc, prevalence of the vasoconstricting Ang II over the vasodilator Ang-(1–7) suggests a dysfunction of the angiotensin-derived cascade that may contribute to dysregulation of vascular tone.

Abbreviations: Ang I, angiotensin I; Ang II, angiotensin II; Ang-(1–7), angiotensin-(1–7); BK, bradykinin; dSSc, diffuse systemic sclerosis; EC, endothelial cell; lSSc, limited systemic sclerosis; NEP, neutral endopeptidase; NO, nitric oxide; PGF1, prostaglandin F1; PGI2, prostaglandin I2; RAS, renin–angiotensin system; SP, substance P; SSc, systemic sclerosis

Keywords: angiotensin (1–7); angiotensin converting enzyme; endothelium; neutral endopeptidase; systemic sclerosis

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Relevant Article

Why is gout so poorly managed?

Eliseo Pascual and Francisca Sivera
Ann Rheum Dis 2007 66: 1269-1270. [Extract] [Full Text] [PDF]