Angiotensin-converting enzyme 2 regulates renal atrial natriuretic peptide through angiotensin-(1–7)

2012 ◽  
Vol 123 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Stella Bernardi ◽  
Wendy C. Burns ◽  
Barbara Toffoli ◽  
Raelene Pickering ◽  
Maryio Sakoda ◽  
...  

Deficiency of ACE2 (angiotensin-converting enzyme 2), which degrades Ang (angiotensin) II, promotes the development of glomerular lesions. However, the mechanisms explaining why the reduction in ACE2 is associated with the development of glomerular lesions have still to be fully clarified. We hypothesized that ACE2 may regulate the renoprotective actions of ANP (atrial natriuretic peptide). The aim of the present study was to investigate the effect of ACE2 deficiency on the renal production of ANP. We evaluated molecular and structural abnormalities, as well as the expression of ANP in the kidneys of ACE2-deficient mice and C57BL/6 mice. We also exposed renal tubular cells to AngII and Ang-(1–7) in the presence and absence of inhibitors and agonists of RAS (renin–angiotensin system) signalling. ACE2 deficiency resulted in increased oxidative stress, as well as pro-inflammatory and profibrotic changes. This was associated with a down-regulation of the gene and protein expression on the renal production of ANP. Consistent with a role for the ACE2 pathway in modulating ANP, exposing cells to either Ang-(1–7) or ACE2 or the Mas receptor agonist up-regulated ANP gene expression. This work demonstrates that ACE2 regulates renal ANP via the generation of Ang-(1–7). This is a new mechanism whereby ACE2 counterbalances the renal effects of AngII and which explains why targeting ACE2 may be a promising strategy against kidney diseases, including diabetic nephropathy.

1998 ◽  
Vol 94 (2) ◽  
pp. 165-173 ◽  
Author(s):  
Robert Zietse ◽  
Frans H. Derkx ◽  
Willem Weimar ◽  
Maarten A. Schalekamp

1. In diabetes mellitus a selective increase in the excretion of albumin generally precedes the occurrence of demonstrable loss of glomerular size-selectivity. However, even in this (microalbuminuric) phase of diabetic nephropathy a defect in glomerular barrier function can be demonstrated during infusion of atrial natriuretic peptide. 2. The aim of this study was to investigate whether angiotensin-converting enzyme inhibition could prevent the proteinuric response to atrial natriuretic peptide in these patients. We performed infusions of atrial natriuretic peptide (0.01 μg min−1 kg−1) in 10 patients with insulin-dependent diabetes mellitus and microalbuminuria (urinary albumin excretion 90 ± 44 mg/day), both before and after 1 month of treatment with enalapril (20 mg once daily). 3. Despite a 40% reduction in proteinuria, angiotensin-converting enzyme inhibition did not prevent the atrial natriuretic peptide-induced increase in protein excretion. Both before and during angiotensin-converting enzyme inhibition, atrial natriuretic peptide infusion resulted in a significant increase in the fractional excretion of large dextran molecules, which is compatible with an increase in flow through large unrestrictive ‘shunt' pores. Atrial natriuretic peptide infusion also induced an increase in the transcapillary escape rate of albumin and angiotensin-converting enzyme inhibition also failed to prevent this effect of atrial natriuretic peptide on peripheral capillary permeability. 4. We conclude that angiotensin-converting enzyme inhibition during 1 month does not correct the capillary barrier function defect in patients with diabetes mellitus and microalbuminuria that is unmasked by atrial natriuretic peptide infusion.


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