Comparative efficacy of empagliflozin and drugs of baseline therapy in post-infarct heart failure in normoglycemic rats.

The study aimed to investigate the effects of the sodium-glucose co-transporter 2 (SGLT2) inhibitor empagliflozin on chronic heart failure (HF) in normoglycemic rats. The effects of empagliflozin were compared with the standard medications for HF, e.g., angiotensin-converting enzyme (ACE) inhibitor fosinopril, beta-blocker bisoprolol, and aldosterone antagonist spironolactone. Myocardial infarction (MI) was induced in male Wistar rats via permanent ligation of the left descending coronary artery. One-month post MI, 50 animals were randomized into 5 groups (n = 10): vehicle-treated, empagliflozin (1.0 mg/kg), fosinopril (10 mg/kg), bisoprolol (10 mg/kg), and spironolactone (20 mg/kg). All medications except empagliflozin were titrated within a month and administered per os daily for 3 months. Echocardiography, 24-hour urine volume test, and treadmill exercise tests were performed at the beginning and at the end of the study. Treatment with empagliflozin slowed the progression of left ventricular dysfunction: LV sizes and ejection fraction were not changed and the minute volume was significantly increased (from 52.0 ± 15.5 to 61.2 ± 21.2 ml/min) as compared with baseline. No deaths occurred in empagliflozin group. The 24-hour urine volume tends to be higher in empagliflozin and spironolactone groups than in vehicle and fosinopril group. Moreover, empagliflozin exhibited maximal physical exercise tolerance in comparison with all investigated groups (289 ± 27 s versus 183 ± 61 s in fosinopril group, 197 ± 95 s in bisoprolol group, and 47 ± 46 s in spironolactone group, p = 0.0035 for multiple comparisons). Sodium-glucose co-transporter 2 inhibitor empagliflozin reduced progression of left ventricular dysfunction and improved tolerance of physical exercise in normoglycemic rats with HF. Empagliflozin treatment was superior with respect to physical tolerance compared with fosinopril, bisoprolol, and spironolactone.

Regulation of epithelial mesenchymal transition by the renin-angiotensin system: a role for klotho in renal tubular epithelial cells.

Klotho is a putative aging suppressor gene that is primarily expressed in renal tubular epithelial cells. Its expression has been reported to protect against fibrosis in human chronic kidney disease. However, the roles of klotho in epithelial-mesenchymal transition (EMT) and renal fibrosis are yet to be elucidated. The present study aimed to investigate the putative roles of klotho in angiotensin (Ang) II-induced damage of renal tubular epithelial cells. NRK-52E rat cells were treated with various combinations of Ang II, the Ang-converting enzyme inhibitor fosinopril (Fos) and the Ang II receptor antagonist valsartan (Val). The levels of transforming growth factor (TGF)-ß1, soluble klotho, α-smooth muscle actin (α-SMA) and E-cadherin in NRK-52E culture supernatants were measured using enzyme-linked immunosorbent assays. Furthermore, the mRNA and protein expression of TGF-ß1, klotho, α-SMA and E-cadherin was detected using semiquantitative reverse transcription-polymerase chain reaction, immunocytochemistry and Western blot analysis. The results demonstrated that Ang II inhibited the expression of klotho and E-cadherin, while it upregulated the expression of TGF-ß1 and α-SMA, in NRK52E cells. Fos and/or Val were revealed to enhance klotho and E-cadherin expression, and suppress the expression of TGF-ß1 and α-SMA, compared with the Ang II-only group. Furthermore, a positive linear correlation was detected between the expression of klotho and E-cadherin, while negative linear correlations with klotho expression were detected for TGF-ß1 and α-SMA expression. In conclusion, the expression of klotho was demonstrated to be enhanced following treatment with Fos and Val in Ang II-treated NRK-52E cells. The present results indicate that klotho may be involved in the inhibition of Ang II-induced EMT in renal tubular epithelial cells. Therefore, klotho may serve as a protective factor in renal tubulointerstitial fibrosis and aid the treatment of chronic kidney disease (CKD) patients using precision therapy.

Perindopril, fosinopril and losartan inhibited the progression of diethylnitrosamine-induced hepatocellular carcinoma in mice via the inactivation of nuclear transcription factor kappa-B.

Hepatocellular carcinoma (HCC) is a major global health problem. Therapeutic interventions of HCC are still limited because of its complicated molecular pathogenesis. Many reports showed that renin-angiotensin system (RAS) contributes to the development of different types of malignancies. Therefore, the present study aimed to examine the effect of RAS inhibition using perindopril (1 mg/kg), fosinopril (2 mg/kg), or losartan (10 mg/kg) on diethylnitrosamine-induced HCC compared to sorafenib (30 mg/kg). The administration of RAS inhibitors resulted in improved liver function and histologic picture with a reduction in AFP levels. These effects found to be mediated through inactivation of NFкB pathway by the inhibition of NFĸB p65 phosphorylation at the Ser536 residue and inhibition of the phosphorylation-induced degradation of NFĸBia. Consequently, expression levels of cyclin D1 mRNA were significantly lowered. In addition, NFкB-induced TNF-α and TGF-ß1 levels were reduced leading to lower levels of MMP-2 and VEGF. We concluded that RAS inhibition either through inhibiting the ACE or the blockade of AT1R has the same therapeutic benefit and that the tissue affinity of the ACEIs has no impact on its anti-tumor activity. These results suggest that ACEIs and ARBs can serve as promising candidates for further clinical trials in the management of HCC.

Effect of fosinopril on chemerin and VEGF expression in diabetic nephropathy rats.

As the most common and severe complication of diabetes, diabetic nephropathy (DN) has been known to be related with angiotensin converting enzyme inhibitor (ACEI), which can reduce proteinuria and protect renal function. This study analyzed the effect of ACEI analog-fosinopril-on the expression of chemerin and vascular epithelial growth factor (VEGF), in an attempt to reveal the mechanism of ACEI analog on renal protection. A total of 45 SD rats were induced by sreptozotocin for diabetes and were given fosinopril via intragastric cannulation for 12 weeks. After sacrifice, serum and renal chemerin and VEGF contents were quantified by enzyme linked immunosorbent assay (ELISA) and Western blot method, in addition to biochemical laboratory examinations. In diabetic model rats, blood glucose, creatinine, urea nitrogen, 24-hour urinary protein, chemerin and VEGF protein contents were all significantly elevated when compared to those in control group (P<0.05). After fosinopril treatment, blood creatinine, urea nitrogen, 24-hour urinary protein, Chemerin and VEGF protein concentrations were significantly depressed (P<0.05 compared to model group). Positive relationships existed between renal chemerin, VEGF and urea protein levels. Fosinopril may protect renal tissues in diabetes by suppressing chemerin and VEGF protein expression.

Fosinopril Prevents the Development of Tactile Allodynia in a Streptozotocin-Induced Diabetic Rat Model.

The aim of this study was to evaluate fosinopril-induced changes in hemodynamic parameters and tactile allodynia in a rat model of diabetes. Diabetes was induced by streptozotocin (STZ; 50 mg/kg, i.p.) in male Wistar rats. STZ produced hyperglycemia, weight loss, polydipsia, polyphagia, and polyuria as well as long-term arterial hypotension, bradycardia, and tactile allodynia at 10-12 weeks. Daily administration of the angiotensin converting enzyme inhibitor, fosinopril (25 mg/kg, p.o., for 11 weeks) partially reduced the loss of body weight, decreased hyperglycemia, and systolic blood pressure in diabetic rats. Likewise, systemic administration of fosinopril prevented the development and maintenance of tactile allodynia in STZ-induced diabetic rats. These data suggest that fosinopril may have a role in the pharmacotherapy of diabetic neuropathic pain.

Fosinoprilat alleviates lipopolysaccharide (LPS)-induced inflammation by inhibiting TLR4/NF-κB signaling in monocytes.

OBJECTIVE: To evaluate the effect of the fosinoprilat on lipopolysacharides (LPS) induced inflammation in monocytes in vitro. METHODS: Human mononuclear THP1 cells were cultured in complete medium, treated with or without LPS and different concentrations (0,0.25,0.5,1,5,and 10µmol/L) of fosinoprilat. Toll-like receptor (TLR4) mRNA expression was detected by real-time RT-PCR and TLR4 protein level on the surface of monocyte was determined by flow cytometry. Nuclear factor-kappa B (NF-κB) protein level was detected by Western blotting. Cultured supernatant of the THP1 cells in different groups were analyzed by ELISA to detect the levels of interleukin (IL)-1ß, IL-6 and tumor necrosis factor (TNF-α). RESULTS: Both the mRNA and surface protein level of the TLR4 in the THP1 cells were enhanced by the LPS treatment and down-regulated by pretreatment of the fosinoprilat. Accordingly, LPS-induced NF-κB protein was decreased by the fosinoprilat treatment. The increasing secretion of IL-1ß, IL-6 and TNF-α induced by LPS could also be attenuated by the fosinoprilat treatment. CONCLUSION: The inhibitory effect of the fosinoprilat on the TRL4/NF-κB signaling pathway reveals a potential anti-inflammatory and anti-atherosclerosis target.

Fosinopril attenuates the doxorubicin-induced cardiomyopathy by restoring the function of sarcoplasmic reticulum.

Fosinopril, an angiotensin-converting enzyme inhibitor, is known to attenuate cardiomyopathy induced by doxorubicin (DOX); however, the mechanisms of this cardioprotection are not fully elucidated yet. In the present study, experimental cardiomyopathy was induced in rats by administration of DOX with or without co-treatment with fosinopril. Fosinopril was utilized on day 1 or 14 of the treatment with DOX to compare efficacies of early versus late co-treatments. We observed that fosinopril attenuated changes induced by DOX (e.g., less increased heart and left ventricular weights, diminished lung congestion and ascites, attenuated LVEDP and LVSP, and less decreased +dP/dt and -dP/dt). Further, fosinopril diminished the levels of markers of cardiac toxicity (i.e., plasma levels and activities of cardiac enzymes and proteins AST, LDH, CPK, cTnI, and BNP). Fosinopril also prevented DOX-induced decreases in Ca(2+) uptake and restored activity of Ca(2+)-stimulated ATPase in left ventricular sarcoplasmic reticulum. We next tested whether the improved Ca(2+) transport activity in sarcoplasmic reticulum was due to modulation of SERCA2 and phospholamban expressions by fosinopril. Fosinopril attenuated the decrease in SERCA2 and phospholamban expressions caused by DOX. In conclusion, cardioprotective effects of fosinopril in the DOX-induced cardiomyopathy appear to be due to its ability to prevent remodeling of the cardiac sarcoplasmic reticulum membrane.

Angiotensin converting enzyme inhibitors mitigate collagen synthesis induced by a single dose of radiation to the whole thorax.

Our long-term goal is to use angiotensin converting enzyme (ACE) inhibitors to mitigate the increase in lung collagen synthesis that is induced by irradiation to the lung, which could result from accidental exposure or radiological terrorism. Rats (WAG/RijCmcr) were given a single dose of 13 Gy (dose rate of 1.43 Gy/min) of X-irradiation to the thorax. Three structurally-different ACE inhibitors, captopril, enalapril and fosinopril were provided in drinking water beginning 1 week after irradiation. Rats that survived acute pneumonitis (at 6-12 weeks) were evaluated monthly for synthesis of lung collagen. Other endpoints included breathing rate, wet to dry lung weight ratio, and analysis of lung structure. Treatment with captopril (145-207 mg/m(2)/day) or enalapril (19-28 mg/m(2)/day), but not fosinopril (19-28 mg/m(2)/day), decreased morbidity from acute pneumonitis. Lung collagen in the surviving irradiated rats was increased over that of controls by 7 months after irradiation. This increase in collagen synthesis was not observed in rats treated with any of the three ACE inhibitors. Analysis of the lung morphology at 7 months supports the efficacy of ACE inhibitors against radiation-induced fibrosis. The effectiveness of fosinopril against fibrosis, but not against acute pneumonitis, suggests that pulmonary fibrosis may not be a simple consequence of injury during acute pneumonitis. In summary, three structurally-different ACE inhibitors mitigate the increase in collagen synthesis 7 months following irradiation of the whole thorax and do so, even when therapy is started one week after irradiation.

[Fosinopril up-regulates and ameliorates the Ang II induced down-expression of klotho gene in NRK-52E].

OBJECTIVE: To investigate the effect of fosinopril (Fos) on regulating klotho gene expression and elucidate the mechanism of Fos regulating the Angiotensin II (AngII) -induced down-expression of klotho gene. METHODS: Culture cells, NRK-52E, were incubated with media either AngII or Fos or both of all. Experimental groups incubated with Fos (10(-5) mol/L) were divided according to variant points of time for 0 (control), 3, 6, 12, 24 h. Different concentration of Fos was selected to incubated with culture cells for 0 (control), 10(-9) 10(-8), 10(-7), 10(-6), 10(-5) mol/L at the optimal time point (24 h). Five groups, which were A: control; B: AngII (10(-7) mol/L); C: Fos(10(-5) mol/L); D: AngII (10(-7) mol/L) + Fos(10(-5) mol/L) and E: Cells pretreated with Fos(10(-5) mol/L)12 h incubated with AngII (10(-7) mol/L) were divided to observe the effect of Fos on expression of klotho induced by AngII. RT-PCR and immunohistochemistry (IHC) were applied to evaluate the klotho mRNA and protein expression, respectively. RESULTS: Fos up-regulated klotho mRNA in time-dependent manner, and independent of dose-dependent manner; AngII obviously decreased the levels of kloltho mRNA and protein expression in NRK-52E as compared to the control (P < 0.05), the down-regulating effect was reversed by incubating both with AngII and Fos (P < 0.05), and Fos could inhibit the down-regulated expression of klotho gene induced by Ang II in NRK-52E. CONCLUSION: Fosinopril up-regulates klotho mRNA in time-dependent manner, and inhibits the down-regulated expression of klotho gene induced by Ang II.

[Effects of Panax notoginseng saponins on ACE2 and TNF-alpha in rats with post-myocardial infarction-ventricular remodeling].

OBJECTIVE: To research the effects of Panax notoginseng saponins (PNS) on angiotensin-converting enzymes 2 ( ACE2) and tumor necrosis factor-alpha (TNF-alpha) in rats with post-myocardial infarction ventricular remodeling. METHODS: Models of acute myocardial infarction (AMI) were produced by ligation of left anterior descending coronary artery, 24 hours after operation the rats were randomly divided into control and experiment groups, then respectively administrated with NS, fosinopril and low, middle and high dosage of PNS for four consecutive weeks. To observe effects of PNS on malondialdehyde (MDA), nitric oxide (NO), glutathione peroxidase (GSH-Px), ACE2 and TNF-alpha in rats with post-myocardial infarction ventricular remodeling. RESULTS: Compared with NS group, MDA significantly decreased, the activity of GSH-Px significantly increased (P < 0.05 or P < 0.01), NO of the high-dose PNS group decreased (P < 0.05), Compared with the NS group, ACE2 increased and TNF-a significantly decreased in low-dose PNS group, middle and high-dose groups (P < 0.05). CONCLUSION: PNS can stimulate ACE2 to inhibit the expression of TNF-alpha and enhance the antioxidance. PNS can reduce pathological injury of cardiac myocytes in myocardial ischemia and cardiac muscle, which can improve ventricular remodeling.

Role of Fosinopril and Valsartan on Klotho Gene Expression Induced by Angiotensin II in Rat Renal Tubular Epithelial Cells.

BACKGROUND/AIMS: Klotho gene, a new anti-aging gene, is mainly expressed in the kidney tubules. Several studies have found the relationship between klotho and emergence and development of renal diseases. This study set out to explore the role of fosinopril (Fos) and valsartan (Val) on klotho expression induced by angiotensin II (Ang II) in rat renal tubular epithelial cells (NRK-52E). METHODS: NRK-52E cells were divided into five groups according to the treatment of Ang II, Fos and Val. Transforming growth factor-ß1 (TGF-ß1), p38, phospho-p38 (p-p38), p53, and Sp1 protein expression were determined by immunohistochemical and Western blotting analysis. Klotho expression was detected by reverse transcription-polymerase chain reaction and Western blotting analysis. RESULTS: Ang II upregulated TGF-ß1, p-p38 and p53 expression, and inhibited Sp1 and klotho expression in NRK-52E cells. After the intervention of Fos and/or Val, TGF-ß1, p-p38 and p53 expression were downregulated, Sp1 and klotho expression were upregulated. TGF-ß1 and p53, Sp1 and klotho expression exhibited a positive linear correlation, respectively. CONCLUSION: We conclude that Fos and Val have a protective role in Ang II-induced renal damage, and it may be through mechanism of inhibiting TGF-ß1, p-p38 and p53 expression, thus upregulating Sp1 and klotho expression.

[Effects of fosinopril and losartan on the expression of Toll- like receptor 4 in renal tubular epithelia cells].

OBJECTIVE: To determine the mechanism of Toll-like receptor 4(TLR4) in hypertensive renal injury and the protective effect of fosinopril(Fos) and losartan(Los). METHODS: NRK-52E was incubated into 5 groups: NRK-52E (normal control), NRK-52E+AngII, NRK-52E+AngII+Fos(10(-5) mmol/L),and NRK-52E+AngII+Los(10(-5) mmol/L), NRK-52E +AngII+Fos(10(-5) mmol/L)+Los(10(-5) mmol/L). TLR4-specific RNAi plasmids were stably transfected into NRK-52E. After 24 h, TLR4, IL-6, and TNF-alpha mRNAs were examined by reverse transcription-polymerase chain reaction(RT-PCR). TLR4 proteins were detected by Western blot, NF-kappaB nuclear translocations were tested by immunocytochemistry,and IL-6 and TNF-alpha supernatant levels were tested by enzyme linked immuno-sorbent assay(ELISA). RESULTS: TLR4, NF-kappaB, IL-6,and TNF-alpha were highly expressed in AngII induced NRK-52E(P<0.01). In NRK-52E that was stably transfected TLR4-special RNAi plamids, TLR4 protein and mRNA expression were obviously inhibited(P<0.05). After stimulation by AngII, the TLR4, IL-6, TNF-alpha levels in the stabe transfection group were increased compared with the normal group(P<0.05). Fos or/and Los down-regulated TLR4, IL-6, and TNF-alpha expressions(P<0.05), but no cooperation was observed. CONCLUSION: TLR4 may lead to inflammatory reaction in hypertensive renal injury. Fos or/and Los can decrease the expressions of TLR4 and correlate inflammatory factors, which may be part of the renal protective mechanism.

Inhibition of the renin-angiotensin system attenuates the development of liver fibrosis and oxidative stress in rats.

1. The present study was designed to investigate the potential antifibrotic and anti-oxidant effects of lisinopril, fosinopril and losartan in an experimental rat model of liver injury using carbon tetrachloride (CCl(4)). 2. First, the potential hepatoprotective dose of each drug was screened against CCl(4)-induced acute hepatotoxicity. Then, we chose the minimum hepatoprotective dose of each drug to further investigate the mechanisms involved in the hepatoprotection using a chronic model of hepatotoxicity induced by CCl(4). 3. Liver function was assessed in addition to histopathological examination. Furthermore, oxidative stress markers (reduced glutathione (GSH) and lipid peroxides levels) and markers of fibrosis (hydroxyproline content and liver fibrosis area) were assessed. 4. It was found that treatment of animals with different drugs concomitantly with CCl(4) significantly counteracted the changes in liver function induced by CCl(4) (except fosinopril). In addition, the drugs ameliorated the histopathological changes induced by CCl(4). All drugs significantly counteracted lipid peroxidation and GSH depletion (except fosinopril) compared with the CCl(4)-intoxicated group. Moreover, the drugs studied significantly reduced liver hydroxyproline levels and the area of fibrosis compared with the CCl(4)-intoxicated group. 5. In conclusion, the present study provides evidence for the hepatoprotective effect of lisinopril, fosinopril and losartan. Both lisinopril and losartan was found to have better hepatoprotective potential than fosinopril against CCl(4)-induced hepatotoxicity. These hepatoprotective effects can be explained on the basis of anti-oxidant and antifibrotic mechanisms, mainly enhancement of GSH and reduction of lipid peroxidation and fibrosis.

Effects of angiotensin-converting enzyme inhibitors and beta-adrenergic blockers on retinal vascular endothelial growth factor expression in rat diabetic retinopathy.

Vascular endothelial growth factor (VEGF) plays a pivotal role in diabetic retinopathy (DR) and hypertension has been identified as an independent risk factor for DR. The aim of the present study was to: (1) explore whether beta-adrenergic blockers influence retinal VEGF expression; (2) determine the effect of angiotensin-converting enzyme inhibitors (ACEI) on retinal VEGF expression independently of their anti-hypertensive actions; and (3) investigate the correlation between retinal VEGF expression and changes in retinal capillary basement membrane thickness (BMT). Streptozotocin-induced diabetic rats and control animals were assigned at random to receive the beta-adrenergic blocker propranolol, the ACEI fosenopril sodium, or vehicle for 24 weeks. Enzyme linked immunosorbent assay, immunohistochemistry, Western blot, and real-time reverse transcription-polymerase chain reaction were used to assess VEGF protein and mRNA expression. Computer-assisted morphometric measurements of transmission electron microscopy photographs were performed to evaluate BMT. Vitreous fluid and retinal VEGF protein and retinal VEGF mRNA expression were significantly higher in diabetic rats than in control rats, with a significant reduction in fosenopril sodium-treated diabetic rats (p<0.01). There was no significant difference in VEGF levels in diabetic rats and propranolol-treated diabetic rats (p>0.05), but there was a significant difference in VEGF protein and mRNA expression in propranolol-treated diabetic rats and fosenopril sodium-treated diabetic rats (p<0.01) without any significant difference in systolic blood pressure in the latter two groups (p>0.05). There was a significant correlation between the level of retinal VEGF expression and changes in retinal BMT (p<0.01). These findings suggest that the effect of ACEI on retinal VEGF expression is independent of their anti-hypertensive actions and that ACEI could offer particular benefits beyond blood pressure reduction in the treatment of DR with or without hypertension. beta-adrenergic blockers had no influence on retinal VEGF expression in normal or diabetic rats.

Pretreatment with fosinopril or valsartan reduces myocardial no-reflow after acute myocardial infarction and reperfusion.

BACKGROUND: Both fosinopril and valsartan are effective in protecting endothelial function. We hypothesized that they may also reduce myocardial no-reflow. In addition, suppression of adenosine triphosphate-sensitive K (KATP) channel opening is an important mechanism for myocardial no-reflow. Therefore, this study sought to assess the effect of fosinopril and valsartan on myocardial no-reflow and explore the possible mechanism. METHODS: Coronary ligation area and the area of no-reflow were determined with both myocardial contrast echocardiography in vivo and pathological means in 56 mini-swine randomized into seven study groups: eight in control, eight in fosinopril-pretreated (1 mg/kg/day) for 3 days, eight in fosinopril and glibenclamide (KATP channel blocker)-pretreated, eight in valsartan-pretreated (2 mg/kg/day) for 3 days, eight in valsartan and glibenclamide-pretreated, eight in glibenclamide-treated and eight in sham-operated. An acute myocardial infarction and reperfusion model was created with a 3-h occlusion of the coronary artery followed by a 2-h reperfusion. The levels of KATP channel proteins (SUR2, Kir6.1, and Kir6.2) in the reflow and no-reflow myocardium were quantified by Western blotting. RESULTS: Compared with the control group, both fosinopril and valsartan significantly improved ventricular function, decreased area of no-reflow (myocardial contrast echocardiography: from 78.5+/-4.5 to 24.5+/-2.7 and 24.3+/-3.6%, pathological means: from 82.3+/-1.9 to 25.2+/-3.2 and 24.9+/-4.4% of ligation area, respectively; all P<0.01), reduced necrosis size from 98.5+/-1.3 to 88.9+/-3.6 and 89.1+/-3.1% of ligation area, respectively (both P<0.05). They also increased the levels of SUR2 and Kir6.2 (P<0.01), but had no effect on the level of Kir6.1 (P>0.05). A combination of fosinopril or valsartan with glibenclamide significantly increased area of no-reflow (P<0.05) and decreased the levels of SUR2 and Kir6.2 (P<0.01). CONCLUSIONS: Pretreatment with fosinopril or valsartan can reduce myocardial no-reflow. This beneficial effect is due to activation of the KATP channel.

Role of Angiotensin-converting enzyme and neutral endopeptidase in flow-dependent remodeling.

Omapatrilat inhibits neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE). We compared the effects of omapatrilat (40 mg/kg/day, p.o.) to fosinopril (40 mg/kg/day, p.o.) on flow-induced vascular remodeling in New Zealand genetically hypertensive (GH) rats. Both drugs equally reduced blood pressure (BP) initially, but systolic BP and pulse pressure were reduced more by omapatrilat after 1 week. Carotid remodeling was induced by partial ligation of the left common carotid artery (LCA). There was little remodeling in untreated GH rats - measured as outer diameter to body weight (OD/BW vs. before ligation): 97 +/- 1% of initial LCA (low flow) and 107 +/- 3% of initial right common carotid artery (RCA, high flow). In contrast, OD/BW increased to 118 +/- 5% (p < 0.05) of initial RCA after omapatrilat versus 108 +/- 2% (p = 0.96) after fosinopril. The major change was increased RCA lumen area which was significantly larger in omapatrilat-treated animals (127% vs. control) than fosinopril-treated animals (103% vs. control). The increase in outward remodeling after omapatrilat treatment correlated weakly with vascular cGMP levels and decreased systolic BP. The results suggest that dual inhibition of NEP/ACE may have greater effects than ACE inhibition alone on vessel remodeling in hypertension.

Effect of dual angiotensin converting enzyme/neutral endopeptidase inhibition, angiotensin converting enzyme inhibition, or AT1 antagonism on coronary microvasculature in spontaneously hypertensive rats.

Microvascular remodeling contributes to increased cardiovascular risk in hypertension. The dual angiotensin converting enzyme (ACE) and neutral endopeptidase (NEP) inhibitor omapatrilat improves small artery remodeling in hypertension. The aim of the present study was to compare effects of omapatrilat to the ACE inhibitor fosinopril and the AT(1) antagonist irbesartan on the coronary microvasculature in spontaneously hypertensive rats (SHR). Ten-week-old SHR were treated for 10 weeks with omapatrilat (20 or 40 mg/kg/d), irbesartan (50 mg/kg/d), or fosinopril (20 mg/kg/d). Arterioles and capillaries were identified in the myocardium by immunolabeling. After 10 weeks, systolic blood pressure (BP) was significantly reduced in treated versus untreated SHR (P <.01). Myocardial arteriolar density/mm(2) was higher (P <.05) in untreated SHR versus Wistar-Kyoto (WKY), and was reduced by omapatrilat (at both high and low doses) and by fosinopril (P <.01). Irbesartan decreased only subepicardial arteriolar density (P <.05). Myocardial capillary density/mm(2) was decreased in untreated SHR versus WKY (P <.01), associated with increase in cardiomyocyte cross-sectional area and cardiomyocyte-to-capillary ratio, and a decrease in myocyte density. Omapatrilat (at both high and low doses) resulted in increased capillary density, decreased myocyte hypertrophy and cardiomyocyte to capillary ratio, and increased myocyte density (P <.01). Fosinopril and irbesartan reduced myocyte hypertrophy of SHR, but had no effect on capillary density. Dual ACE/NEP inhibition was more effective than ACE inhibition or AT(1) antagonism in improving microvascular and cardiomyocyte remodeling in the hypertensive heart. This suggests a role for NEP inhibition added to blockade of the renin-angiotensin system that may explain the greater efficacy of omapatrilat.

Protection of organic trauma in sinoaortic-denervated rats treated with fosinopril.

AIM: To study the importance of blood pressure variability in organ protection for long-term treatment with fosinopril in-sinoaortic-denervated (SAD) rats. METHODS: Fosinopril (15 mg.kg-1.d-1) was given in rat chow for 16 weeks after SAD surgery. Blood pressure variability (BPV) was recorded during 24 h in conscious state. Histopathological changes were evaluated with light microscope and computer-assisted image analysis. RESULTS: Long-term treatment with fosinopril significantly decreased BPV in SAD rats. The thickness of the left ventricular wall, collagen fraction of the left ventricle and glomerulosclerosis score were all positively related to BPV in untreated and fosinopril-treated SAD rats. Fosinopril markedly prevented the damages of target organs in SAD rats. CONCLUSION: Long-term treatment with fosinopril showed obvious organ protection in SAD rats. The decrease in BPV may significantly contribute to organ protection.

Hemodynamic and humoral effects of vasopeptidase inhibition in canine hypertension.

Vasopeptidase inhibitors are potent new antihypertensive agents. The dual inhibition of ACE and neutral endopeptidase may result in synergistic humoral effects with unique hemodynamic actions. We investigated the hemodynamic and neurohumoral effects of vasopeptidase inhibition in conscious dogs made hypertensive by bilateral renal wrapping and subsequently instrumented for long-term assessment of left ventricular pressure and volume (n=8). Intravenous vasopeptidase inhibition (omapatrilat, 30 micromol/kg over 10 minutes) reduced peak left ventricular pressure (171+/-6 versus 130+/-6 mm Hg immediately after infusion, P<0.01) through arterial vasodilation (arterial elastance, 9.8+/-0.8 to 5.8+/-1.6 mm Hg/mL, P<0.01) and preload reduction (left ventricular end-diastolic volume, 51.1+/-6.8 to 46.0+/-6.9 mL, P<0.01). At 60 minutes, preload decreased further (40.5+/-5.9 mL, P<0.01 versus baseline). Vasopeptidase inhibition increased plasma levels of adrenomedullin (41.2+/-9.6 versus 72.3+/-15 pg/mL, P<0.01), whereas levels of the natriuretic peptides and cGMP were unchanged. Similar hemodynamic and humoral effects were observed with long-term therapy. Neither an equimolar dose of an ACE inhibitor (fosinopril) nor exogenous adrenomedullin had as potent of a hypotensive effect, and neither reduced preload. In summary, the potent short-term and long-term hypotensive effects of vasopeptidase inhibition were prominently mediated by preload reduction, an effect not reproduced by ACE inhibition nor adrenomedullin augmentation and not associated with enhanced natriuretic peptide levels. Combined arterial vasodilation and preload reduction may confer additional potency as well as unique cardioprotective effects. Synergistic effects on humoral and probably endothelial vasodilatory factors appear to be important in mediating the unique hemodynamic profile of vasopeptidase inhibition in this form of experimental hypertension.

Physiologic consequences of vasopeptidase inhibition in humans: effect of sodium intake.

The in vivo inhibition of angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP) were monitored simultaneously by sequentially measuring the urinary excretion of N-Acetyl-Ser-Asp-Lys-Pro and of the atrial natriuretic factor to compare the magnitude and the duration of action of a vasopeptidase inhibitor, omapatrilat, and an ACE inhibitor, fosinopril. Single oral doses of 40 or 80 mg of omapatrilat or 20 mg of fosinopril were administered to 24 normotensive, sodium-depleted or -replete volunteers in a placebo-controlled crossover study. ACE inhibition persisted longer after treatment with omapatrilat than with fosinopril, and there was no major difference between the effects of 40 and 80 mg of omapatrilat. The duration of NEP inhibition by omapatrilat was shorter than that of ACE inhibition. Although omapatrilat effectively inhibited NEP, it had a mild and transient natriuretic effect and did not increase natriuresis more than fosinopril. Omapatrilat induced a decrease in BP and an increase in plasma renin more rapidly and more effectively than fosinopril. The BP and renin effects of omapatrilat persisted despite high sodium intake, which neutralized the effects of fosinopril. The simultaneous inhibition of ACE and NEP may be more effective in reducing BP than the inhibition of ACE alone and less dependent on sodium balance.