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

We elucidated the role of collecting duct kinin B2 receptor (B2R) in the development of salt-sensitivity and angiotensin II (ANG II)-induced hypertension. To this end, we used a Cre-Lox recombination strategy to generate mice lacking Bdkrb2 gene for B2R in the collecting duct (Hoxb7-Cre(tg/+):Bdkrb2(flox/flox)). In 3 groups of control (Bdkrb2(flox/flox)) and 3 groups of UB(Bdkrb2-/-) mice, systolic blood pressure (SBP) responses to high salt intake (4 or 8% NaCl; HS) were monitored by radiotelemetry in comparison with standard salt diet (0.4% NaCl) prior to and during subcutaneous ANG II infusion (1000 ng/min/kg) via osmotic minipumps. High salt intakes alone for 2 weeks did not alter SBP in either strain. ANG II significantly increased SBP equally in control (121 ± 2 to 156 ± 3 mmHg) and UB(Bdkrb2-/-) mice (120 ± 2 to 153 ± 2 mmHg). The development of ANG II-induced hypertension was exacerbated by 4%HS in both control (125 ± 3 to 164 ± 5 mmHg) and UB(Bdkrb2-/-) mice (124 ± 2 to 162 ± 3 mmHg) during 2 weeks. Interestingly, 8%HS caused a more profound and earlier ANG II-induced hypertension in UB(Bdkrb2-/-) (129 ± 2 to 166 ± 3 mmHg) as compared to control (128 ± 2 to 158 ± 2 mmHg) and it was accompanied by body weight loss and increased mortality. In conclusion, targeted inactivation of B2R in the renal collecting duct does not cause salt-sensitivity; however, collecting duct B2R attenuates the hypertensive actions of ANG II under conditions of very high salt intake.

• Keywords
• Angiotensin II, Cre recombinase, bradykinin receptor, collecting duct, high salt diet, hypertension, kallikrein–kinin system,
• MeSH
• Angiotensin II metabolism   MeSH
• Gene Knockout Techniques MeSH
• Hypertension * metabolism   physiopathology   MeSH
• Blood Pressure * drug effects   physiology   MeSH
• Sodium Chloride, Dietary adverse effects   MeSH
• Disease Models, Animal MeSH
• Mice MeSH
• Receptor, Bradykinin B2 genetics   MeSH
• Kidney Tubules, Collecting * metabolism   physiopathology   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice 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
• Angiotensin II MeSH
• Sodium Chloride, Dietary MeSH
• Receptor, Bradykinin B2 MeSH

BACKGROUND: Small renal arteries have a significant role in the regulation of renal hemodynamics and blood pressure (BP). To study potential changes in the regulation of vascular function in hypertension, we examined renal vasodilatory responses of small arteries from nonclipped kidneys of the 2-kidney, 1-clip Goldblatt hypertensive rats to native epoxyeicosatrienoic acids (EETs) that are believed to be involved in the regulation of renal vascular function and BP. A total of 2 newly synthesized EET analogues were also examined. MATERIALS AND METHODS: Renal interlobular arteries isolated from the nonclipped kidneys on day 28 after clipping were preconstricted with phenylephrine, pressurized and the effects of a 14,15-EET analogue, native 14,15-EET and 11,12-ether-EET-8ZE, an analogue of 11,12-EET, on the vascular diameter were determined and compared to the responses of arteries from the kidneys of sham-operated rats. RESULTS: In the arteries from nonclipped kidneys isolated in the maintenance phase of Goldblatt hypertension, the maximal vasodilatory response to 14,15-EET analogue was 30.1 ± 2.8% versus 49.8 ± 7.2% in sham-operated rats; the respective values for 11,12-ther-EET-8ZE were 31.4 ± 6.4% versus 80.4 ± 6%, and for native EETs they were 41.7 ± 6.6% versus 62.8 ± 4.4% (P ≤ 0.05 for each difference). CONCLUSIONS: We propose that reduced vasodilatory action and decreased intrarenal bioavailability of EETs combined with intrarenal angiotensin II levels that are inappropriately high for hypertensive rats underlie functional derangements of the nonclipped kidneys of 2-kidney, 1-clip Goldblatt hypertensive rats. These derangements could play an important role in pathophysiology of sustained BP elevation observed in this animal model of human renovascular hypertension.

• Keywords
• 1-Clip Goldblatt hypertension, 2-Kidney, Epoxyeicosatrienoic acids, Renovascular hypertension, Vasodilatory responses,
• MeSH
• Renal Artery drug effects   physiopathology   MeSH
• Rats MeSH
• 8,11,14-Eicosatrienoic Acid analogs & derivatives   pharmacology   MeSH
• Kidney blood supply   physiopathology   MeSH
• Rats, Sprague-Dawley MeSH
• Hypertension, Renovascular drug therapy   MeSH
• Vasodilation drug effects   MeSH
• Vasodilator Agents pharmacology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• 11,12-epoxy-5,8,14-eicosatrienoic acid MeSH Browser
• 14,15-epoxy-5,8,11-eicosatrienoic acid MeSH Browser
• 8,11,14-Eicosatrienoic Acid MeSH
• Vasodilator Agents 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

Recent studies have shown that the long-term antihypertensive action of soluble epoxide hydrolase inhibition (sEH) in angiotensin-II (AngII)-dependent hypertension might be mediated by the suppression of intrarenal AngII levels. To test this hypothesis, we examined the effects of acute (2 days) and chronic (14 days) sEH inhibition on blood pressure (BP) in transgenic rats with inducible AngII-dependent hypertension. AngII-dependent malignant hypertension was induced by 10 days' dietary administration of indole-3-carbinol (I3C), a natural xenobiotic that activates the mouse renin gene in Cyp1a1-Ren-2 transgenic rats. BP was monitored by radiotelemetry. Acute and chronic sEH inhibition was achieved using cis-4-(4-(3-adamantan-1-yl-ureido)cyclohexyloxy) benzoic acid, given at doses of 0.3, 3, 13, 26, 60 and 130 mg/L in drinking water. At the end of experiments, renal concentrations of epoxyeicosatrienoic acids, their inactive metabolites dihydroxyeicosatrienoic acids and AngII were measured. Acute BP-lowering effects of sEH inhibition in I3C-induced rats was associated with a marked increase in renal epoxyeicosatrienoic acids to dihydroxyeicosatrienoic acids ratio and acute natriuresis. Chronic treatment with cis-4-(4-(3-adamantan-1-yl-ureido)cyclohexyloxy) benzoic acid in I3C-induced rats elicited dose-dependent persistent BP lowering associated with a significant reduction of plasma and kidney AngII levels. Our findings show that the acute BP-lowering effect of sEH inhibition in I3C-induced Cyp1a1-Ren-2 transgenic rats is mediated by a substantial increase in intrarenal epoxyeicosatrienoic acids and their natriuretic action without altering intrarenal renin-angiotensin system activity. Long-term antihypertensive action of cis-4-(4-(3-adamantan-1-yl-ureido)cyclohexyloxy) benzoic acid in I3C-induced Cyp1a1-Ren-2 transgenic rats is mediated mostly by suppression of intrarenal AngII concentration.

• Keywords
• angiotensin-II, cytochrome P-450 epoxygenase, eicosanoids, epoxyeicosatrienoic acids, hypertension, soluble epoxide hydrolase,
• MeSH
• Angiotensin II metabolism   MeSH
• Antihypertensive Agents pharmacology   MeSH
• Cytochrome P-450 CYP1A1 metabolism   MeSH
• Epoxide Hydrolases antagonists & inhibitors   metabolism   MeSH
• Hypertension drug therapy   metabolism   MeSH
• Indoles metabolism   MeSH
• Blood Pressure drug effects   MeSH
• Rats MeSH
• Kidney drug effects   metabolism   MeSH
• Mice MeSH
• Natriuresis drug effects   MeSH
• Rats, Inbred F344 MeSH
• Rats, Transgenic MeSH
• Renin-Angiotensin System drug effects   MeSH
• Renin metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Mice 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
• Angiotensin II MeSH
• Antihypertensive Agents MeSH
• Cytochrome P-450 CYP1A1 MeSH
• Epoxide Hydrolases MeSH
• indole-3-carbinol MeSH Browser
• Indoles MeSH
• Ren2 protein, rat MeSH Browser
• Renin MeSH

1. The aim of the present study was to test the hypothesis that increasing kidney tissue concentrations of epoxyeicosatrienoic acids (EETs) by preventing their degradation to the biologically inactive dihydroxyeicosatrienoic acids (DHETEs) using blockade of soluble epoxide hydrolase (sEH) would attenuate the progression of chronic kidney disease (CKD). 2. Ren-2 transgenic rats (TGR) after 5/6 renal mass reduction (5/6 NX) served as a model of CKD associated with angiotensin (Ang) II-dependent hypertension. Soluble epoxide hydrolase was inhibited using cis-4-[4-(3-adamantan-1-yl-ureido)cyclohexyloxy]benzoic acid (c-AUCB; 3 mg/L drinking water) for 20 weeks after 5/6 NX. Sham-operated normotensive transgene-negative Hannover Sprague-Dawley (HanSD) rats served as controls. 3. When applied in TGR subjected to 5/6 NX, c-AUCB treatment improved survival rate, prevented the increase in blood pressure, retarded the progression of cardiac hypertrophy, reduced proteinuria and the degree of glomerular and tubulointerstitial injury and reduced glomerular volume. All these organ-protective actions were associated with normalization of the intrarenal EETs:DHETEs ratio, an index of the availability of biologically active EETs, to levels observed in sham-operated HanSD rats. There were no significant concurrent changes of increased intrarenal AngII content. 4. Together, these results show that 5/6 NX TGR exhibit a profound deficiency of intrarenal availability of active epoxygenase metabolites (EETs), which probably contributes to the progression of CKD in this model of AngII-dependent hypertension, and that restoration of intrarenal availability of EETs using long-term c-AUCB treatment exhibits substantial renoprotective actions.

• Keywords
• 5/6 nephrectomy, chronic kidney disease, cytochrome P450 enzymes, end-organ damage, epoxyeicosatrienoic acids, hypertension, renin-angiotensin system, soluble epoxide hydrolase,
• MeSH
• Angiotensin II pharmacology   MeSH
• Renal Insufficiency, Chronic drug therapy   metabolism   MeSH
• Epoxide Hydrolases antagonists & inhibitors   metabolism   MeSH
• Hypertension drug therapy   metabolism   MeSH
• Blood Pressure drug effects   MeSH
• Rats MeSH
• Survival Rate MeSH
• Nephrectomy methods   MeSH
• Rats, Sprague-Dawley MeSH
• Rats, Transgenic metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Female 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
• Angiotensin II MeSH
• Epoxide Hydrolases MeSH