The aim of the present study was to assess systemic circulatory and tissue activities of both the classical arm and of the alternative arm of the renin-angiotensin system (RAS) in a new transgenic rat line (TG7371) that expresses angiotensin-(1-7) (ANG 1-7)-producing fusion protein; the results were compared with the activities measured in control transgene-negative Hannover Sprague-Dawley (HanSD) rats. Plasma and tissue concentrations of angiotensin II (ANG II) and ANG 1-7, and kidney mRNA expressions of receptors responsible for biological actions of ANG II and ANG 1-7 [i.e. ANG II type 1 and type 2 (AT1 and AT2) and Mas receptors] were assessed in TG7371 transgene-positive and in HanSD rats. We found that male TG7371 transgene-positive rats exhibited significantly elevated plasma, kidney, heart and lung ANG 1-7 concentrations as compared with control male HanSD rats; by contrast, there was no significant difference in ANG II concentrations and no significant differences in mRNA expression of AT1, AT2 and Mas receptors. In addition, we found that in male TG7371 transgene-positive rats blood pressure was lower than in male HanSD rats. These data indicate that the balance between the classical arm and the alternative arm of the RAS was in male TGR7371 transgene-positive rats markedly shifted in favor of the latter. In conclusion, TG7371 transgene-positive rats represent a new powerful tool to study the long-term role of the alternative arm of the RAS in the pathophysiology and potentially in the treatment of cardio-renal diseases.

• Keywords
• Angiotensin II, Angiotensin-(1-7), Renin-angiotensin system, TG7371 transgenic rat,
• MeSH
• Angiotensin I * metabolism   MeSH
• Angiotensin II * MeSH
• Cardiovascular Diseases metabolism   genetics   MeSH
• Blood Pressure physiology   MeSH
• Rats MeSH
• Kidney metabolism   MeSH
• Kidney Diseases metabolism   genetics   MeSH
• Peptide Fragments * metabolism   MeSH
• Rats, Sprague-Dawley * MeSH
• Rats, Transgenic * MeSH
• Proto-Oncogene Mas MeSH
• Receptor, Angiotensin, Type 1 genetics   metabolism   MeSH
• Receptors, G-Protein-Coupled genetics   metabolism   MeSH
• Recombinant Fusion Proteins metabolism   MeSH
• Renin-Angiotensin System * physiology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• angiotensin I (1-7) MeSH Browser
• Angiotensin I * MeSH
• Angiotensin II * MeSH
• Peptide Fragments * MeSH
• Proto-Oncogene Mas MeSH
• Receptor, Angiotensin, Type 1 MeSH
• Receptors, G-Protein-Coupled MeSH
• Recombinant Fusion Proteins MeSH

Heart failure (HF) has been declared as global pandemic and current therapies are still ineffective, especially in patients that develop concurrent cardio-renal syndrome. Considerable attention has been focused on the nitric oxide (NO)/soluble guanylyl cyclase (sGC)/cyclic guanosine monophosphate (cGMP) pathway. In the current study, we aimed to investigate the effectiveness of sGC stimulator (BAY41-8543) with the same mode of action as vericiguat, for the treatment of heart failure (HF) with cardio-renal syndrome. As a model, we chose heterozygous Ren-2 transgenic rats (TGR), with high-output heart failure, induced by aorto-caval fistula (ACF). The rats were subjected into three experimental protocols to evaluate short-term effects of the treatment, impact on blood pressure, and finally the long-term survival lasting 210 days. As control groups, we used hypertensive sham TGR and normotensive sham HanSD rats. We have shown that the sGC stimulator effectively increased the survival of rats with HF in comparison to untreated animals. After 60 days of sGC stimulator treatment, the survival was still 50% compared to 8% in the untreated rats. One-week treatment with sGC stimulator increased the excretion of cGMP in ACF TGR (109 ± 28 nnmol/12 h), but the ACE inhibitor decreased it (-63 ± 21 nnmol/12 h). Moreover, sGC stimulator caused a decrease in SBP, but this effect was only temporary (day 0: 117 ± 3; day 2: 108 ± 1; day 14: 124 ± 2 mmHg). These results support the concept that sGC stimulators might represent a valuable class of drugs to battle heart failure especially with cardio-renal syndrome, but further studies are necessary.

• Keywords
• ACF, BAY41-8543, Heart failure, Vericiguat, cGMP, sGC stimulator,
• MeSH
• Cyclic GMP metabolism   MeSH
• Guanylate Cyclase MeSH
• Hypertension * drug therapy   MeSH
• Cardio-Renal Syndrome * MeSH
• Rats MeSH
• Humans MeSH
• Nitric Oxide metabolism   MeSH
• Fistula * MeSH
• Rats, Transgenic MeSH
• Soluble Guanylyl Cyclase metabolism   MeSH
• Heart Failure * drug therapy   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cyclic GMP MeSH
• Guanylate Cyclase MeSH
• Nitric Oxide MeSH
• Soluble Guanylyl Cyclase MeSH

Cytochrome P450 (CYP-450) metabolites of arachidonic acid: epoxyeicosatrienoic acids (EETs) and 20-hydroxyeicosatetraenoic acid (20-HETE) have established role in regulation of blood pressure (BP) and kidney function. EETs deficiency and increased renal formation of 20-HETE contribute to hypertension in spontaneously hypertensive rats (SHR). We explored the effects of 14,15-EET analog (EET-A) and of 20-HETE receptor blocker (AAA) on BP and kidney function in this model. In anesthetized SHR the responses were determined of mean arterial blood pressure (MABP), total renal (RBF), and cortical (CBF) and inner-medullary blood flows, glomerular filtration rate and renal excretion, to EET-A, 5 mg/kg, infused i.v. for 1 h to rats untreated or after blockade of endogenous EETs degradation with an inhibitor (c-AUCB) of soluble epoxide hydrolase. Also examined were the responses to AAA (10 mg/kg/h), given alone or together with EET-A. EET-A significantly increased RBF and CBF (+30% and 26%, respectively), seen already within first 30 min of infusion. The greatest increases in RBF and CBF (by about 40%) were seen after AAA, similar when given alone or combined with EET-A. MABP decreased after EET-A or AAA but not significantly after the combination thereof. In all groups, RBF, and CBF increases preceded the decrease in MABP. We found that in SHR both EET-A and AAA induced renal vasodilation but, unexpectedly, no additive effect was seen. We suggest that both agents have a definite therapeutic potential and deserve further experimental and clinical testing aimed at introduction of novel antihypertensive therapy.

• Keywords
• 20-HETE antagonist, EET analog, epoxyeicosatrienoic acids, hypertension, soluble epoxide hydrolase,
• Publication type
• Journal Article MeSH

It is generally accepted that angiotensin II plays an important role in high blood pressure (BP) development in both 2-kidney-1-clip (2K1C) Goldblatt hypertension and in partial nephrectomy (NX) model of chronic kidney disease (CKD). The contribution of sympathetic nervous system and nitric oxide to BP control in these models is less clear. Partial nephrectomy or stenosis of the renal artery was performed in adult (10-week-old) male hypertensive heterozygous Ren-2 transgenic rats (TGR) and normotensive control Hannover Sprague Dawley (HanSD) rats and in Wistar rats. One and four weeks after the surgery, basal blood pressure (BP) and acute BP responses to the consecutive blockade of renin-angiotensin (RAS), sympathetic nervous (SNS), and nitric oxide (NO) systems were determined in conscious rats. Both surgical procedures increased plasma urea, a marker of renal damage; the effect being more pronounced following partial nephrectomy in hypertensive TGR than in normotensive HanSD rats with a substantially smaller effect in Wistar rats after renal artery stenosis. We demonstrated that the renin-angiotensin system does not play so fundamental role in blood pressure maintenance during hypertension development in either CKD model. By contrast, a more important role is exerted by the sympathetic nervous system, the activity of which is increased in hypertensive TGR-NX in the developmental phase of hypertension, while in HanSD-NX or Wistar-2K1C it is postponed to the established phase. The contribution of the vasoconstrictor systems (RAS and SNS) was increased following hypertension induction. The role of NO-dependent vasodilation was unchanged in 5/6 NX HanSD and in 2K1C Wistar rats, while it gradually decreased in 5/6 NX TGR rats.

• MeSH
• Renal Insufficiency, Chronic complications   metabolism   physiopathology   MeSH
• Hypertension complications   metabolism   physiopathology   MeSH
• Blood Pressure physiology   MeSH
• Rats MeSH
• Disease Models, Animal MeSH
• Rats, Sprague-Dawley MeSH
• Rats, Transgenic MeSH
• Rats, Wistar MeSH
• Renin-Angiotensin System * MeSH
• Sympathetic Nervous System physiopathology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

INTRODUCTION: Previous studies in Ren-2 transgenic hypertensive rats (TGR) after 5/6 renal ablation (5/6 NX) have shown that besides pharmacological blockade of the renin-angiotensin system (RAS) also increasing kidney tissue epoxyeicosatrienoic acids (EET) levels by blocking soluble epoxide hydrolase (sEH), an enzyme responsible for degradation of EETs, and endothelin type A (ETA) receptor blockade retards chronic kidney disease (CKD) progression. This prompted us to evaluate if this progression will be alleviated by the addition of sEH inhibitor and ETA receptor antagonist to the standard complex blockade of RAS (angiotensin-converting enzyme inhibitor plus angiotensin II type 1 receptor blocker) in rats with established CKD. METHODS: The treatment regimens were initiated 6 weeks after 5/6 NX in TGR, and the follow-up period was 60 weeks. RESULTS: The addition of sEH inhibition to RAS blockade improved survival rate, further reduced albuminuria and renal glomerular and kidney tubulointerstitial injury, and attenuated the decline in creatinine clearance - all this as compared with 5/6 NX TGR treated with RAS blockade alone. Addition of ETA receptor antagonist to the combined RAS and sEH blockade not only offered no additional renoprotection but, surprisingly, also abolished the beneficial effects of adding sEH inhibitor to the RAS blockade. CONCLUSION: These data indicate that pharmacological strategies that combine the blockade of RAS and sEH could be a novel tool to combat the progression of CKD. Any attempts to further extend this therapeutic regimen should be made with extreme caution.

• Keywords
• 5/6 Renal mass reduction, Chronic kidney disease, Endothelin A receptor blocker, Hypertension, Renin-angiotensin system, Soluble epoxide hydrolase inhibitor,
• MeSH
• Endothelin A Receptor Antagonists pharmacology   MeSH
• Renal Insufficiency, Chronic prevention & control   MeSH
• Epoxide Hydrolases antagonists & inhibitors   MeSH
• Hypertension MeSH
• Rats MeSH
• Nephrectomy MeSH
• Rats, Transgenic MeSH
• Receptor, Endothelin A MeSH
• Renin-Angiotensin System drug effects   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Endothelin A Receptor Antagonists MeSH
• Epoxide Hydrolases MeSH
• Receptor, Endothelin A MeSH

Epoxyeicosatrienoic acids (EETs) are also known as epoxyeicosanoids that have renal and cardiovascular actions. These renal and cardiovascular actions can be regulated by soluble epoxide hydrolase (sEH) that degrades and inactivates EETs. Extensive animal hypertension studies have determined that vascular, epithelial transport, and anti-inflammatory actions of EETs lower blood pressure and decrease renal and cardiovascular disease progression. Human studies have also supported the notion that increasing EET levels in hypertension could be beneficial. Pharmacological and genetic approaches to increase epoxyeicosanoids in several animal models and humans have found improved endothelial vascular function, increased sodium excretion, and decreased inflammation to oppose hypertension and associated renal and cardiovascular complications. These compelling outcomes support the concept that increasing epoxyeicosanoids via sEH inhibitors or EET analogs could be a valuable hypertension treatment.

• MeSH
• Antihypertensive Agents therapeutic use   MeSH
• Epoxide Hydrolases antagonists & inhibitors   metabolism   MeSH
• Hypertension drug therapy   metabolism   physiopathology   MeSH
• Eicosanoids metabolism   therapeutic use   MeSH
• Enzyme Inhibitors therapeutic use   MeSH
• Blood Pressure drug effects   MeSH
• Humans MeSH
• Signal Transduction MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Antihypertensive Agents MeSH
• Epoxide Hydrolases MeSH
• Eicosanoids MeSH
• Enzyme Inhibitors MeSH

Epoxyeicosatrienoic acids (EETs) and their synthetic analogs have cardiovascular protective effects. Here, we investigated the action of a novel EET analog EET-B on the progression of post-myocardial infarction (MI) heart failure in spontaneously hypertensive rats (SHR). Adult male SHR were divided into vehicle- and EET-B (10 mg/kg/day; p.o., 9 weeks)-treated groups. After 2 weeks of treatment, rats were subjected to 30-min left coronary artery occlusion or sham operation. Systolic blood pressure (SBP) and echocardiography (ECHO) measurements were performed at the beginning of study, 4 days before, and 7 weeks after MI. At the end of the study, tissue samples were collected for histological and biochemical analyses. We demonstrated that EET-B treatment did not affect blood pressure and cardiac parameters in SHR prior to MI. Fractional shortening (FS) was decreased to 18.4 ± 1.0% in vehicle-treated MI rats compared with corresponding sham (30.6 ± 1.0%) 7 weeks following MI induction. In infarcted SHR hearts, EET-B treatment improved FS (23.7 ± 0.7%), markedly increased heme oxygenase-1 (HO-1) immunopositivity in cardiomyocytes and reduced cardiac inflammation and fibrosis (by 13 and 19%, respectively). In conclusion, these findings suggest that EET analog EET-B has beneficial therapeutic actions to reduce cardiac remodeling in SHR subjected to MI.

• Keywords
• blood pressure, epoxyeicosatrienoic acid, heart failure, myocardial infarction, spontaneously hypertensive rat,
• MeSH
• Heme Oxygenase-1 genetics   metabolism   MeSH
• Myocardial Infarction drug therapy   genetics   metabolism   physiopathology   MeSH
• Blood Pressure MeSH
• Rats MeSH
• Arachidonic Acids administration & dosage   chemistry   MeSH
• Humans MeSH
• Disease Models, Animal MeSH
• Rats, Inbred SHR MeSH
• Heart physiopathology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Humans MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• Heme Oxygenase-1 MeSH
• Arachidonic Acids MeSH

An association between congestive heart failure (CHF) and chronic kidney disease (CKD) results in extremely poor patient survival rates. Previous studies have shown that increasing kidney epoxyeicosatrienoic acids (EETs) by blocking soluble epoxide hydrolase (sEH), an enzyme responsible for EETs degradation, improves the survival rate in CHF induced by aorto-caval fistula (ACF) and attenuates CKD progression. This prompted us to examine if sEH inhibitor treatment would improve the outcome if both experimental conditions are combined. Fawn-hooded hypertensive (FHH) rats, a genetic model showing early CKD development was employed, and CHF was induced by ACF. Treatment with an sEH inhibitor was initiated 4 weeks after ACF creation, in FHH and in fawn-hooded low-pressure (FHL) rats, a control strain without renal damage. The follow-up period was 20 weeks. We found that ACF FHH rats exhibited substantially lower survival rates (all the animals died by week 14) as compared with the 64% survival rate observed in ACF FHL rats. The former group showed pronounced albuminuria (almost 30-fold higher than in FHL) and reduced intrarenal EET concentrations. The sEH inhibitor treatment improved survival rate and distinctly reduced increases in albuminuria in ACF FHH and in ACF FHL rats, however, all the beneficial actions were more pronounced in the hypertensive strain. These data indicate that pharmacological blockade of sEH could be a novel therapeutic approach for the treatment of CHF, particularly under conditions when it is associated with CKD.

• Keywords
• chronic kidney disease, congestive heart failure, hypertension, renin-angiotensin-aldosterone system, soluble epoxide hydrolase inhibitor,
• Publication type
• Journal Article MeSH

BACKGROUND/AIMS: We found recently that increasing renal epoxyeicosatrienoic acids (EETs) levels by blocking soluble epoxide hydrolase (sEH), an enzyme responsible for EETs degradation, shows renoprotective actions and retards the progression of chronic kidney disease (CKD) in Ren-2 transgenic hypertensive rats (TGR) after 5/6 renal ablation (5/6 NX). This prompted us to examine if additional protection is provided when sEH inhibitor is added to the standard renin-angiotensin system (RAS) blockade, specifically in rats with established CKD. METHODS: For RAS blockade, an angiotensin-converting enzyme inhibitor along with an angiotensin II type receptor blocker was used. RAS blockade was compared to sEH inhibition added to the RAS blockade. Treatments were initiated 6 weeks after 5/6 NX in TGR and the follow-up period was 60 weeks. RESULTS: Combined RAS and sEH blockade exhibited additional positive impact on the rat survival rate, further reduced albuminuria, further reduced glomerular and tubulointerstitial injury, and attenuated the decline in creatinine clearance when compared to 5/6 NX TGR subjected to RAS blockade alone. These additional beneficial actions were associated with normalization of the intrarenal EETs deficient and a further reduction of urinary angiotensinogen excretion. CONCLUSION: This study provides evidence that addition of pharmacological inhibition of sEH to RAS blockade in 5/6 NX TGR enhances renoprotection and retards progression of CKD, notably, when applied at an advanced stage.

• Keywords
• 5/6 nephrectomy, Chronic kidney disease, Epoxyeicosatrienoic acids, Hypertension, Renin-angiotensin system, Soluble epoxide hydrolase,
• MeSH
• Albuminuria drug therapy   MeSH
• Renal Insufficiency, Chronic drug therapy   mortality   physiopathology   surgery   MeSH
• Epoxide Hydrolases antagonists & inhibitors   MeSH
• Hypertension MeSH
• Angiotensin-Converting Enzyme Inhibitors therapeutic use   MeSH
• Drug Therapy, Combination MeSH
• Rats MeSH
• Survival Rate MeSH
• Nephrectomy MeSH
• Rats, Transgenic MeSH
• Renin-Angiotensin System drug effects   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Epoxide Hydrolases MeSH
• Angiotensin-Converting Enzyme Inhibitors MeSH

The detailed mechanisms determining the course of congestive heart failure (CHF) and associated renal dysfunction remain unclear. In a volume overload model of CHF induced by creation of aorto-caval fistula (ACF) in Hannover Sprague-Dawley (HanSD) rats we explored the putative pathogenetic contribution of epoxyeicosatrienoic acids (EETs), active products of CYP-450 dependent epoxygenase pathway of arachidonic acid metabolism, and compared it with the role of the renin-angiotensin system (RAS). Chronic treatment with cis-4-[4-(3-adamantan-1-yl-ureido) cyclohexyloxy]benzoic acid (c-AUCB, 3 mg/l in drinking water), an inhibitor of soluble epoxide hydrolase (sEH) which normally degrades EETs, increased intrarenal and myocardial EETs to levels observed in sham-operated HanSD rats, but did not improve the survival or renal function impairment. In contrast, chronic angiotensin-converting enzyme inhibition (ACEi, trandolapril, 6 mg/l in drinking water) increased renal blood flow, fractional sodium excretion and markedly improved survival, without affecting left ventricular structure and performance. Hence, renal dysfunction rather than cardiac remodeling determines long-term mortality in advanced stage of CHF due to volume overload. Strong protective actions of ACEi were associated with suppression of the vasoconstrictor/sodium retaining axis and activation of vasodilatory/natriuretic axis of the renin-angiotensin system in the circulating blood and kidney tissue.

• MeSH
• Angiotensin I blood   MeSH
• Angiotensin II blood   MeSH
• Benzoates pharmacology   therapeutic use   MeSH
• Epoxide Hydrolases antagonists & inhibitors   MeSH
• Epoxy Compounds metabolism   MeSH
• Angiotensin-Converting Enzyme Inhibitors MeSH
• Rats MeSH
• 8,11,14-Eicosatrienoic Acid analogs & derivatives   blood   metabolism   MeSH
• Kidney metabolism   MeSH
• Urea analogs & derivatives   pharmacology   therapeutic use   MeSH
• Disease Models, Animal MeSH
• Myocardium metabolism   MeSH
• Random Allocation MeSH
• Peptide Fragments blood   MeSH
• Drug Evaluation, Preclinical MeSH
• Renal Insufficiency blood   etiology   prevention & control   MeSH
• Renin-Angiotensin System drug effects   MeSH
• Heart Failure blood   complications   diagnostic imaging   drug therapy   MeSH
• Ultrasonography MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• 4-(4-(3-adamantan-1-ylureido)cyclohexyloxy)benzoic acid MeSH Browser
• angiotensin I (1-7) MeSH Browser
• Angiotensin I MeSH
• Angiotensin II MeSH
• Benzoates MeSH
• Epoxide Hydrolases MeSH
• Epoxy Compounds MeSH
• Angiotensin-Converting Enzyme Inhibitors MeSH
• 8,11,14-Eicosatrienoic Acid MeSH
• Urea MeSH
• Peptide Fragments MeSH