scholarly journals Portal pressure responses and angiotensin peptide production in rat liver are determined by relative activity of ACE and ACE2

2009 ◽  
Vol 297 (1) ◽  
pp. G98-G106 ◽  
Author(s):  
Chandana B. Herath ◽  
John S. Lubel ◽  
Zhiyuan Jia ◽  
Elena Velkoska ◽  
David Casley ◽  
...  
Keyword(s):  
Portal Pressure ◽  
Ace Inhibition ◽  
Neutral Endopeptidase ◽  
Relative Activity ◽  
Ang Ii ◽  
Experimental Cirrhosis ◽  
Angiotensin Peptide ◽  
And Control ◽  
Nep Inhibition

Angiotensin converting enzyme (ACE) 2 activity and angiotensin-(1-7) [Ang-(1-7)] levels are increased in experimental cirrhosis; however, the pathways of hepatic Ang-(1-7) production have not been studied. This study investigated the role of ACE2, ACE, and neutral endopeptidase (NEP) in the hepatic formation of Ang-(1-7) from angiotensin I (Ang I) and Ang II and their effects on portal resistance. Ang I or Ang II were administered to rat bile duct ligated (BDL) and control livers alone and in combination with the ACE inhibitor lisinopril, the ACE and NEP inhibitor omapatrilat, or the ACE2 inhibitor MLN4760 ( n = 5 per group). BDL markedly upregulated ACE, ACE2, and NEP. Ang-(1-7) was produced from Ang II in healthy and in BDL livers and was increased following ACE inhibition and decreased by ACE2 inhibition. In contrast, Ang-(1-7) production from Ang I was minimal and not affected by ACE or NEP inhibition. Surprisingly, ACE2 inhibition in BDLs dramatically increased Ang-(1-7) production from Ang I, an effect abolished by ACE2/NEP inhibition. Ang II and Ang I induced greater portal pressure increases in BDL livers than controls. The effects of Ang I were closely correlated with Ang II production and were strongly attenuated by both ACE and ACE/NEP inhibition. These findings show that the major substrate for hepatic production of Ang-(1-7) is Ang II and this is catalyzed by ACE2. Ang I is largely converted to Ang II by ACE, and net conversion of Ang I to Ang-(1-7) is small. NEP has the ability to generate large amounts of Ang-(1-7) in the BDL liver from Ang I only when ACE2 activity is greatly decreased or inhibited.

Role of endothelium-derived relaxing factors in the renal response to vasoactive agents in hypothyroid rats

2003 ◽  
Vol 285 (1) ◽  
pp. E182-E188 ◽  
Author(s):  
Juan Manuel Moreno ◽  
Rosemary Wangensteen ◽  
Juan Sainz ◽  
Isabel Rodríguez-Gomez ◽  
Virginia Chamorro ◽  
...  
Keyword(s):  
Vascular Reactivity ◽  
Ang Ii ◽  
Vasoactive Agents ◽  
Normal Response ◽  
No Donor ◽  
Increased Sensitivity ◽  
Renal Vascular ◽  
And Control ◽  
Renal Responses

This study analyzed the role of nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) in the abnormal renal vascular reactivity of hypothyroid rats. Renal responses to vasoconstrictors [VC: phenylephrine (PHE) and ANG II] and vasodilators [VD: ACh, sodium nitroprusside (SNP), and papaverine (PV)] were studied in kidneys from control and hypothyroid rats under normal conditions and after NO or EDHF blockade. NO was blocked by the administration of Nω-nitro-l-arginine methyl ester (l-NAME) and EDHF by the administration of tetraethylammonium (TEA) or by an increased extracellular K+. The response to VC was also evaluated after endothelium removal. Hypothyroid kidneys showed reduced responsiveness to PHE and a normal response to ANG II. l-NAME and TEA administration produced an increased sensitivity to PHE and to ANG II in control preparations. l-NAME also increased the response to PHE in hypothyroid kidneys, but the differences between control and hypothyroid kidneys were maintained. TEA administration did not change the response to either VC in hypothyroid preparations. In endothelium-removed preparations, TEA was unable to increase pressor responsiveness to VC. Hypothyroid kidneys showed reduced responsiveness to ACh and SNP and normal response to PV. The differences between hypothyroid and control preparations in the responses to ACh and SNP were maintained after l-NAME or increased K+. In conclusion, this study shows that 1) the attenuated response to PHE in hypothyroidism is not related to an increased production of endothelium-derived relaxing factors NO and EDHF; 2) the response to VC in hypothyroid preparations is insensitive to EDHF blockade; and 3) hypothyroid preparations have a reduced reactivity to the NO donor, and NO-independent vasodilatation remains unaffected.

scholarly journals Apelin protects against abdominal aortic aneurysm and the therapeutic role of neutral endopeptidase resistant apelin analogs

2019 ◽  
Vol 116 (26) ◽  
pp. 13006-13015 ◽  
Author(s):  
Wang Wang ◽  
Mengcheng Shen ◽  
Conrad Fischer ◽  
Ratnadeep Basu ◽  
Saugata Hazra ◽  
...  
Keyword(s):  
Abdominal Aortic Aneurysm ◽  
Aortic Aneurysm ◽  
Aortic Rupture ◽  
Critical Role ◽  
Neutral Endopeptidase ◽  
Negative Regulator ◽  
Ang Ii ◽  
Direct Role ◽  
Abdominal Aortic

Abdominal aortic aneurysm (AAA) remains the second most frequent vascular disease with high mortality but has no approved medical therapy. We investigated the direct role of apelin (APLN) in AAA and identified a unique approach to enhance APLN action as a therapeutic intervention for this disease. Loss of APLN potentiated angiotensin II (Ang II)-induced AAA formation, aortic rupture, and reduced survival. Formation of AAA was driven by increased smooth muscle cell (SMC) apoptosis and oxidative stress inApln−/yaorta and in APLN-deficient cultured murine and human aortic SMCs. Ang II-induced myogenic response and hypertension were greater inApln−/ymice, however, an equivalent hypertension induced by phenylephrine, an α-adrenergic agonist, did not cause AAA or rupture inApln−/ymice. We further identified Ang converting enzyme 2 (ACE2), the major negative regulator of the renin-Ang system (RAS), as an important target of APLN action in the vasculature. Using a combination of genetic, pharmacological, and modeling approaches, we identified neutral endopeptidase (NEP) that is up-regulated in human AAA tissue as a major enzyme that metabolizes and inactivates APLN-17 peptide. We designed and synthesized a potent APLN-17 analog, APLN-NMeLeu9-A2, that is resistant to NEP cleavage. This stable APLN analog ameliorated Ang II-mediated adverse aortic remodeling and AAA formation in an established model of AAA, high-fat diet (HFD) inLdlr−/−mice. Our findings define a critical role of APLN in AAA formation through induction of ACE2 and protection of vascular SMCs, whereas stable APLN analogs provide an effective therapy for vascular diseases.

Role of angiotensin II in brown adipose thermogenesis during cold acclimation

1993 ◽  
Vol 265 (6) ◽  
pp. E860-E865 ◽  
Author(s):  
L. A. Cassis
Keyword(s):  
Angiotensin Ii ◽  
Renin Angiotensin System ◽  
Synaptic Cleft ◽  
Neuronal Uptake ◽  
Ang Ii ◽  
Angiotensin System ◽  
Brown Adipose ◽  
Wet Weight ◽  
And Control

The role of angiotensin II (ANG II) in increased sympathetic neuroeffector mechanisms observed in cold-induced thermogenesis of brown adipose tissue (BAT) was examined. Cold exposure (4 degrees C) for 7 days resulted in an increase in interscapular fat (ISF) ANG II content expressed per gram wet weight or per lobe of ISF, without concomitant changes in plasma components of the renin-angiotensin system. Additionally, in ISF slices preloaded with [3H]norepinephrine (NE), ANG II (10 nM) resulted in an increase (3-fold) in evoked 3H overflow from ISF slices from cold-exposed rats compared with ambient temperature controls. However, although basal 3H outflow was increased (2-fold) in ISF slices from cold-exposed rats, evoked 3H overflow was not different between ISF slices from cold-exposed and control rats. Specific neuronal uptake of [3H]NE in ISF slices from cold-exposed rats was decreased by 64%. Administration of the non-peptide AT1-receptor antagonist losartan to cold-exposed rats resulted in complete inhibition of ANG II-mediated presynaptic facilitation of evoked 3H overflow from ISF slices. However, losartan administration had no effect on cold-induced increases in ANG II content, protein content, and decreases in neuronal [3H]NE uptake in ISF. Results from these studies suggest that cold-induced thermogenesis of BAT results in alterations in presynaptic ANG II facilitation of NE release and defects in removal of NE from the synaptic cleft (neuronal uptake), both of which would enhance sympathetic nervous system-mediated thermogenesis. Furthermore, these results demonstrate a role for ANG II in enhanced sympathetic activity of cold-induced thermogenesis in BAT.

Pivotal role of the renin-angiotensin system in Lyon hypertensive rats

1997 ◽  
Vol 273 (5) ◽  
pp. R1793-R1799 ◽  
Author(s):  
Pierre Lantelme ◽  
Ming Lo ◽  
Laurent Luttenauer ◽  
Jean Sassard
Keyword(s):  
Renin Angiotensin System ◽  
Ace Inhibition ◽  
Ang Ii ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Adult Age ◽  
Enhanced Sensitivity ◽  
Regional Hemodynamics ◽  
Renal Vascular

We assessed the role of the renin-angiotensin system (RAS) in Lyon genetically hypertensive (LH) and normotensive (LN) rats by measuring 1) kidney renin and prorenin contents; 2) effects of early, prolonged angiotensin-converting enzyme (ACE) inhibition on blood pressure (BP) and regional hemodynamics; and 3) acute and chronic responses to angiotensin II (ANG II) and norepinephrine (NE). At the adult age, LH rats differed from LN rats by elevated BP, left ventricle weight, and vascular resistances, especially in the kidneys, associated with lower kidney renin and prorenin contents. ACE inhibition (perindopril, 3 mg ⋅ kg−1 ⋅ 24 h−1 orally from 3 to 15 wk of age) suppressed the development of hypertension, cardiac hypertrophy, and the increase in renal vascular resistances. No specific hypersensitivity to ANG II could be disclosed in acute conditions. In perindopril-treated LH rats, a 4-wk infusion of ANG II (200 ng ⋅ kg−1 ⋅ min−1) but not of NE (1,000 ng ⋅ kg−1 ⋅ min−1) restored hypertension, mimicked the hemodynamic alterations seen in untreated LH rats, and produced a brief sodium retention. It is concluded that in LH rats, despite a low basal renin secretion, hypertension and hemodynamic abnormalities 1) are fully dependent on an active RAS and 2) may involve an enhanced sensitivity to the chronic effects of ANG II.

Role of the renin-angiotensin system in the systemic microvascular inflammation of alveolar hypoxia

2007 ◽  
Vol 292 (5) ◽  
pp. H2285-H2294 ◽  
Author(s):  
Norberto C. Gonzalez ◽  
Julie Allen ◽  
Eric J. Schmidt ◽  
Alfred J. Casillan ◽  
Teresa Orth ◽  
...  
Keyword(s):  
Ace Inhibitor ◽  
Renin Angiotensin System ◽  
Ace Inhibition ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Alveolar Hypoxia ◽  
Microvascular Inflammation

Alveolar hypoxia (AH) induces widespread systemic inflammation. Previous studies have shown dissociation between microvascular Po2 and inflammation. Furthermore, plasma from AH rats (PAHR) induces mast cell (MC) activation, inflammation, and vasoconstriction in normoxic cremasters, while plasma from normoxic rats does not produce these responses. These results suggest that inflammation of AH is triggered by a blood-carried agent. This study investigated the involvement of the renin-angiotensin system (RAS) in the inflammation of AH. Both an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin II (ANG II) receptor blocker (ANG II RB) inhibited the leukocyte-endothelial adherence produced by AH, as well as the inflammation produced by PAHR in normoxic rat cremasters. MC stabilization with cromolyn blocked the effects of PAHR but not those of topical ANG II on normoxic cremasters, suggesting ANG II generation via MC activation by PAHR. This was supported by the observation that ACE inhibition and ANG II RB blocked the leukocyte-endothelial adherence produced by the MC secretagogue compound 48/80. These results suggest that the intermediary agent contained in PAHR activates MC and stimulates the RAS, leading to inflammation, and imply an RAS role in AH-induced inflammation.

scholarly journals Major role for ACE-independent intrarenal ANG II formation in type II diabetes

2010 ◽  
Vol 298 (1) ◽  
pp. F37-F48 ◽  
Author(s):  
Sungmi Park ◽  
Benjamin J. Bivona ◽  
Hiroyuki Kobori ◽  
Dale M. Seth ◽  
Mark C. Chappell ◽  
...  
Keyword(s):  
Serine Protease ◽  
Type Ii Diabetes ◽  
Ace Inhibition ◽  
Receptor Blockade ◽  
Type Ii ◽  
Afferent Arteriole ◽  
Ang Ii ◽  
Protease Inhibition ◽  
Protein Activity ◽  
And Control

Combination therapy of angiotensin-converting enzyme (ACE) inhibition and AT1 receptor blockade has been shown to provide greater renoprotection than ACE inhibitor alone in human diabetic nephropathy, suggesting that ACE-independent pathways for ANG II formation are of major significance in disease progression. Studies were performed to determine the magnitude of intrarenal ACE-independent formation of ANG II in type II diabetes. Although renal cortical ACE protein activity [2.1 ± 0.8 vs. 9.2 ± 2.1 arbitrary fluorescence units (AFU)·mg−1·min−1] and intensity of immunohistochemical staining were significantly reduced and ACE2 protein activity (16.7 ± 3.2 vs. 7.2 ± 2.4 AFU·mg−1·min−1) and intensity elevated, kidney ANG I (113 ± 24 vs. 110 ± 45 fmol/g) and ANG II (1,017 ± 165 vs. 788 ± 99 fmol/g) levels were not different between diabetic and control mice. Afferent arteriole vasoconstriction due to conversion of ANG I to ANG II was similar in magnitude in kidneys of diabetic (−28 ± 3% at 1 μM) and control (−23 ± 3% at 1 μM) mice; a response completely inhibited by AT1 receptor blockade. In control kidneys, afferent arteriole vasoconstriction produced by ANG I was significantly attenuated by ACE inhibition, but not by serine protease inhibition. In contrast, afferent arteriole vasoconstriction produced by intrarenal conversion of ANG I to ANG II was significantly attenuated by serine protease inhibition, but not by ACE inhibition in diabetic kidneys. In conclusion, there is a switch from ACE-dependent to serine protease-dependent ANG II formation in the type II diabetic kidney. Pharmacological targeting of these serine protease-dependent pathways may provide further protection from diabetic renal vascular disease.

Characterization of angiotensin IV-degrading enzymes and receptors on rat mesangial cells

1998 ◽  
Vol 275 (4) ◽  
pp. F535-F542 ◽  
Author(s):  
Dominique Chansel ◽  
Stanislas Czekalski ◽  
Sophie Vandermeersch ◽  
Emmanuel Ruffet ◽  
Marie-Claude Fournié-Zaluski ◽  
...  
Keyword(s):  
Mesangial Cells ◽  
Biological Effects ◽  
Neutral Endopeptidase ◽  
Cytosolic Calcium ◽  
Ang Ii ◽  
Degrading Enzymes ◽  
Specific Receptors ◽  
Ang Iv

Because mesangial cells (MC) are a target and a degradation site for angiotensin II (ANG II), we characterized the degrading enzymes and receptors of ANG IV, a metabolite of ANG II, on these cells. ANG IV was metabolized into its NH2-terminal deleted peptides, ANG II-(4–8), ANG II-(5–8), and ANG II-(6–8) by rat MC. Total protection of ANG IV was obtained only when PC-18, a specific aminopeptidase N (APN) inhibitor, and JFH-27A, a mixed inhibitor of dipeptidylaminopeptidase (DAP) and neutral endopeptidase (NEP), were simultaneously added. In contrast, thiorphan, an NEP inhibitor, was inactive. These results demonstrate the exclusive role of APN and DAP in ANG IV degradation.125I-labeled ANG IV binding was studied in the presence of PC-18 and JFH-27A to suppress ligand degradation. Under these conditions, ANG IV-specific receptors could be demonstrated with a K D of 1.8 nM and a density of 55 fmol/mg. In contrast with MC, no evidence for ANG IV receptors could be obtained in freshly isolated glomeruli. ANG IV stimulated cytosolic calcium concentration in MC, whereas its NH2-terminal deleted metabolites were inactive. Therefore, ANG IV must be protected from degradation by APN and DAP in studies on the nonimmediate biological effects of this peptide.

Cuff-induced vascular intima thickening is influenced by titration of the Ace gene in mice

2009 ◽  
Vol 37 (3) ◽  
pp. 225-230 ◽  
Author(s):  
Silvia Lacchini ◽  
Andrea S. Heimann ◽  
Fabiana S. Evangelista ◽  
Leandro Cardoso ◽  
Gustavo J. J. Silva ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Ace Inhibition ◽  
Ang Ii ◽  
Pharmacological Interventions ◽  
Vascular Abnormality ◽  
Vascular Abnormalities ◽  
Ace Gene ◽  
Angiotensin I Converting Enzyme ◽  
Vascular Activity

We tested the hypothesis that small changes in angiotensin I-converting enzyme (ACE) expression can alter the vascular response to injury. Male mice containing one, two, three, and four copies of the Ace gene with no detectable vascular abnormality or changes in blood pressure were submitted to cuff-induced femoral artery injury. Femoral thickening was higher in 3- and 4-copy mice (42.4 ± 4.3% and 45.7 ± 6.5%, respectively) compared with 1- and 2-copy mice (8.3 ± 1.3% and 8.5 ± 0.9%, respectively). Femoral ACE levels from control and injured vessels were assessed in 1- and 3-copy Ace mice, which represent the extremes of the observed response. ACE vascular activity was higher in 3- vs. 1-copy Ace mice (2.4-fold, P < 0.05) in the control uninjured vessel. Upon injury, ACE activity significantly increased in both groups [2.41-fold and 2.14-fold ( P < 0.05) for 1- and 3-copy groups, respectively] but reached higher levels in 3- vs. 1-copy Ace mice ( P < 0.05). Pharmacological interventions were then used as a counterproof and to indirectly assess the role of angiotensin II (ANG II) on this response. Interestingly, ACE inhibition (enalapril) and ANG II AT1 receptor blocker (losartan) reduced intima thickening in 3-copy mice to 1-copy mouse values ( P < 0.05) while ANG II treatment significantly increased intima thickening in 1-copy mice to 3-copy mouse levels ( P < 0.05). Together, these data indicate that small physiologically relevant changes in ACE, not associated with basal vascular abnormalities or blood pressure levels, do influence the magnitude of cuff-induced neointima thickening in mice.

scholarly journals Ang II-Induced Hypertension Exacerbates the Pathogenesis of Tuberculosis

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2478
Author(s):  
Soo-Na Cho ◽  
Ji-Ae Choi ◽  
Junghwan Lee ◽  
Sang-Hun Son ◽  
Seong-Ahn Lee ◽  
...  
Keyword(s):  
Cell Death ◽  
Mycobacterial Infection ◽  
Incidence Rates ◽  
Control Group ◽  
Ang Ii ◽  
Induced Hypertension ◽  
Foamy Macrophages ◽  
And Control ◽  
Normal Controls

It has been known that infection plays a role in the development of hypertension. However, the role of hypertension in the progression of infectious diseases remain unknown. Many countries with high rates of hypertension show geographical overlaps with those showing high incidence rates of tuberculosis (TB). To explore the role of hypertension in tuberculosis, we compared the effects of hypertension during mycobacterial infection, we infected both hypertensive Angiotensin II (Ang II) and control mice with Mycobacterium tuberculosis (Mtb) strain H37Ra by intratracheal injection. Ang II-induced hypertension promotes cell death through both apoptosis and necrosis in Mtb H37Ra infected mouse lungs. Interestingly, we found that lipid accumulation in pulmonary tissues was significantly increased in the hypertension group compared to the normal controls. Ang II-induced hypertension increases the formation of foamy macrophages during Mtb infection and it leads to cell death. Moreover, the hypertension group showed more severe granuloma formation and fibrotic lesions in comparison with the control group. Finally, we observed that the total number of mycobacteria was increased in the lungs in the hypertension group compared to the normal controls. Taken together, these results suggest that hypertension increases intracellular survival of Mtb through formation of foamy macrophages, resulting in severe pathogenesis of TB.

A novel mechanism for angiotensin II formation in streptozotocin-diabetic rat glomeruli

2005 ◽  
Vol 288 (6) ◽  
pp. F1183-F1190 ◽  
Author(s):  
Rekha Singh ◽  
Ashok K. Singh ◽  
David J. Leehey
Keyword(s):  
Angiotensin Ii ◽  
Renin Angiotensin System ◽  
Diabetic Rats ◽  
Diabetic Rat ◽  
Ang Ii ◽  
Sprague Dawley ◽  
New Information ◽  
Sprague Dawley Rats ◽  
And Control

Recent evidence suggests that the intrarenal renin-angiotensin system (RAS) may play an important role in the development of glomerular changes associated with diabetic nephropathy. In this study, the glomerular RAS was examined in male Sprague-Dawley rats made diabetic with streptozotocin (STZ), and the findings compared with those obtained in control nondiabetic rats. In diabetic rat glomerular extracts, angiotensinogen and angiotensin II (ANG II) levels were increased significantly by 2.2- and 1.9-fold, respectively, compared with nondiabetic controls. No significant differences in ANG I and angiotensin-converting enzyme (ACE) levels were observed between these groups. The HPLC analysis of the glomerular extracts demonstrated that exogenous ANG I was converted into various ANG peptides including ANG II, ANG(1–9), and ANG(1–7). A significant increase in formation of ANG II from exogenous ANG I was observed in STZ rats compared with control rats. Preincubation of glomerular extracts with captopril resulted in a 20–30% decrease in ANG II conversion from exogenous ANG I in diabetic and control rats. The possible role of ANG(1–9) in formation of ANG II was examined by HPLC. Exogenous ANG(1–9) in glomerular extracts was converted into ANG II, this conversion being significantly higher in STZ rats than in control rats. These findings provide new information that ANG(1–9) is produced in rat glomerular extracts, can be converted to ANG II, and that this conversion is also stimulated in diabetic rat glomeruli. Thus this study demonstrates that in diabetic rats, glomerular ANG II levels are increased due to an increase in angiotensinogen and an increase in the formation of ANG II.

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