Angiotensin III ; Humans

PURPOSE: Angiotensin(ANG) II regulates tone of penile smooth muscle for erection. ANG III is a product converted from ANG II by aminopeptidase A. The effects of ANG III have not been clarified in the penile corpus cavernosum. The purpose of the present experiment was to determine whether the ANG III has regulatory function in the control of rabbit corpus cavernosum smooth muscle tone. MATERIALS AND METHODS: A strip of rabbit corpus cavernosum was mounted in an organ chamber to measure the isometric tension. We compared the effects of ANG III(10-7M to 10-5M), ANG II(10-8M to 10-6M) and ANG I(10-7M to 10-5M) on the contractility of the corpus cavernosum smooth muscle. RESULTS: ANG III, ANG II, and ANG I contracted corpus cavernosum smooth muscle strips dose-dependently. The contraction of smooth muscle induced by ANG III was 10 fold less by ANG II. Contractile response to ANG III was not attenuated by captopril(angiotensin converting enzyme inhibitor). Contractile response to ANG III was significantly inhibited by Dup 753 of 10-7M(type 1 specific ANG II receptor inhibitor) but not inhibited by PD 123,319 of 10-6M(type 2 specific ANG II inhibitor). CONCLUSIONS: The present results suggest that ANG III is involved in the regulation of corpus cavernosum smooth muscle tone, and contractile effect to ANG III produced via activation of type 1 ANG II (AT1) receptor. The rank order of potency of contraction was as follows, ANG II>ANG IIIANG I.
Angiotensin I* ; Angiotensin II* ; Angiotensin III* ; Angiotensins* ; Glutamyl Aminopeptidase ; Losartan ; Muscle, Smooth*

BACKGROUND: Angiotensin converting enzyme (ACE) is heavily expressed in the lung and plays a role in the metabolism of angiotensin II, bradykinin and substance P. Nitric oxides, including those produced by endothelial nitric oxide synthase (ecNOS), may regulate vascular and airway tone in the lung and influence various aspects of airway homeostasis. They are potentially involved in the pathogenesis of asthma, but the role of ACE and ecNOS gene in bronchial asthma is not completely understood. OBJECTIVE: To examine the possible involvement of ACE and ecNOS genes in the genetic basis for bronchial asthma, we investigated the association between genetic polymorphism and bronchial asthma, and its severity. METHOD: We determined the ACE and ecNOS genotypes by the polymerase chain reaction in 160 patients with bronchial asthma and 121 healthy subjects. Severity of asthma was classified by the guideline of NHLBI/WHO workshop. RESULTS: The frequency of the ID genotypes of ACE and bb genotype of ecNOS was highest in both groups, respectively. The distribution of ACE genotypes did not differ between the two groups (p=0.27). There was a higher frequency of the bb genotype of ecNOS in the asthma group than in the control population (p=0.004). In asthmatic patients, there were no differences in the distribution of ACE and ecNOS genotypes in different severity groups (p= 0.17, 0.06). CONCLUSION: These results suggest that the polymorphism of the ecNOS gene, not ACE gene, may be associated with development of asthma. But, the severity of asthma may not be influenced by polymorphisms of the ecNOS and ACE genes.
Angiotensin II ; Angiotensins* ; Asthma* ; Bradykinin ; Education ; Genotype ; Homeostasis ; Humans ; Lung ; Metabolism ; Nitric Oxide Synthase Type III* ; Oxides ; Peptidyl-Dipeptidase A* ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Substance P

Mitochondrial fission can occur via activation of dynamin-related protein 1 (Drp1), which participates in the mitochondrial membrane scission process. The present study was designed to investigate the effect of angiotensin II (AngII) on mitochondrial fission and fusion in human umbilical vascular endothelial cells (HUVECs). And we further inquire into whether Mdivi-1, a newly identified pharmacological inhibitor of Drp1, can prevent endothelial dysfunction induced by AngII. The HUVECs were treated with AngII alone or in combination with Mdivi-1. Western blot was used to detect protein expressions of Drp1, endothelial nitric oxide synthase (eNOS) and apoptosis-related enzymes. MitoTracker Red and JC-1 dye were used to detect mitochondrial morphology and membrane potential, respectively. DCFH-DA probe was used to access intracellular reactive oxygen species (ROS) generation. Transwell assay was used to evaluate cell migration. Annexin V/PI staining was used to assess cellular apoptosis. The results showed that, in cultured HUVECs, AngII (1 × 10mol/L, 12 h) treatment significantly upregulated the expression of Drp1 followed by increased apoptosis and decreased eNOS expression. The treatment of AngII resulted in a change in mitochondrial morphology from elongated to uniformly punctate organelles, which was accompanied by decreased mitochondrial membrane potential. Furthermore, Mdivi-1 significantly protected against AngII-induced endothelial dysfunction, as shown by increased mitochondrial membrane potential and eNOS expression, reduced ROS level, decreased apoptosis and migration ability. Taking together, our data suggest that inhibition of Drp1 with Mdivi-1 can restore AngII-induced endothelial dysfunction.
Angiotensin II ; Apoptosis ; Cells, Cultured ; Endothelial Cells ; Fluoresceins ; Humans ; Membrane Potential, Mitochondrial ; Microtubule-Associated Proteins ; Mitochondria ; Mitochondrial Proteins ; Nitric Oxide Synthase Type III ; Quinazolinones

BACKGROUND AND OBJECTIVES: The renin angiotensin system seems to play an important role in the development of cardiac and vascular hypertrophy in hypertension. The changes in pathology, and gene expressions of the angiotensin II receptor type 1A (ATIA) and angiotensin converting enzyme (ACE) were investigated in order to explore the effects of losartan in spontaneously hypertensive rat (SHR) models. MATERIALS AND METHODS: Twelve week-old male Wistar rats were grouped as follows: control (C) group, hypertension (H) group, and losartan (L) group in which SHR was treated with losartan (10 mg/kg/day). Western blot and reverse transcription-polymerase chain reaction analysis regarding seven genes such as endothelin-1, ACE, ATIA, neutrophil cytosolic factor, brain natriuretic peptide, troponin I, endothelial nitric oxide synthase were performed. RESULTS: Systolic blood pressure was significantly decreased in the L group compared with the H group in weeks 3 and 5. ACE and ATIA proteins in the L group were lower than H group in week 5. CONCLUSION: Losartan reduced blood pressure, cardiac hypertrophy and protein expressions of ACE and ATIA. Changes of protein expressions were more sensitive than changes in pathology. Further study is needed for the differing doses of losartan in SHR models.
Blood Pressure ; Blotting, Western ; Cardiomegaly ; Cytosol ; Endothelin-1 ; Gene Expression ; Humans ; Hypertension ; Hypertrophy ; Losartan ; Male ; Natriuretic Peptide, Brain ; Neutrophils ; Nitric Oxide Synthase Type III ; Peptidyl-Dipeptidase A ; Proteins ; Rats, Inbred SHR ; Rats, Wistar ; Receptors, Angiotensin ; Renin-Angiotensin System ; Troponin I

BACKGROUND: Apart from its blood pressure-lowering effect by blocking the renin-angiotensin-aldosterone system, telmisartan, an angiotensin II type 1 receptor blocker (ARB), exhibits various ancillary effects including cardiovascular protective effects in vitro. Nonetheless, the protective effects of telmisartan in cerebrocardiovascular diseases are somewhat variable in large-scale clinical trials. Dysregulation of endothelial nitric oxide (NO) synthase (eNOS)-derived NO contributes to the developments of various vascular diseases. Nevertheless, the direct effects of telmisartan on endothelial functions including NO production and vessel relaxation, and its action mechanism have not been fully elucidated. Here, we investigated the mechanism by which telmisartan regulates NO production and vessel relaxation in vitro and in vivo. METHODS: We measured nitrite levels in culture medium and mouse serum, and performed inhibitor studies and western blot analyses using bovine aortic endothelial cells (BAECs) and a hyperglycemic mouse model. To assess vessel reactivity, we performed acetylcholine (ACh)-induced vessel relaxation assay on isolated rat aortas. RESULTS: Telmisartan decreased NO production in normoglycemic and hyperglycemic BAECs, which was accompanied by reduced phosphorylation of eNOS at Ser¹¹⁷⁹ (p-eNOS-Ser¹¹⁷⁹). Telmisartan increased the expression of protein phosphatase 2A catalytic subunit (PP2Ac) and co-treatment with okadaic acid completely restored telmisartan-inhibited NO production and p-eNOS-Ser¹¹⁷⁹ levels. Of the ARBs tested (including losartan and fimasartan), only telmisartan decreased NO production and p-eNOS-Ser¹¹⁷⁹ levels, and enhanced PP2Ac expression. Co-treatment with GW9662 had no effect on telmisartan-induced changes. In line with in vitro observations, telmisartan reduced serum nitrite and p-eNOS-Ser¹¹⁷⁹ levels, and increased PP2Ac expression in high fat diet-fed mice. Furthermore, telmisartan attenuated ACh-induced rat aorta relaxation. CONCLUSION: We demonstrated that telmisartan inhibited NO production and vessel relaxation at least in part by PP2A-mediated eNOS-Ser¹¹⁷⁹ dephosphorylation in a peroxisome proliferator-activated receptor γ-independent manner. These results may provide a mechanism that explains the inconsistent cerebrocardiovascular protective effects of telmisartan.
Acetylcholine ; Animals ; Aorta ; Blotting, Western ; Catalytic Domain ; Endothelial Cells ; In Vitro Techniques ; Losartan ; Mice ; Mice, Obese ; Nitric Oxide Synthase Type III ; Nitric Oxide ; Okadaic Acid ; Peroxisomes ; Phosphorylation ; Protein Phosphatase 2 ; Rats ; Receptor, Angiotensin, Type 1 ; Relaxation ; Renin-Angiotensin System ; Vascular Diseases

OBJECTIVETo explore the effects of Angiotensin (ANG)-(1-7) on postangioplasty fibrotic remodeling and the involvement of TGF-beta/Smad signaling pathway in this process.

METHODSThirty two healthy New Zealand white rabbits were randomly divided into 4 groups: sham group, control group, ANG-(1-7) group and ANG-(1-7) + A-779 group. Rabbits underwent angioplasty in the abdominal aorta or sham surgery. Subsequently, an osmotic minipump was implanted for saline, ANG-(1-7) (576 microg x kg(-1) x d(-1)) or ANG-(1-7) + A-779 (576 microg x kg(-1) x d(-1)) delivery. Before and after 4 weeks treatment, the levels of ANG II in plasma were measured by ELISA. At week 4, angiography and histomorphometric analysis were performed, mRNA levels of collagen I and III were assayed by RT-PCR and protein levels of TGF-beta1 and Smad2 in local vessel were assayed by Western blot.

RESULTSFollowing 4 weeks treatment, ANG-(1-7) and ANG-(1-7) + A-779 group displayed a significant elevation in lumen diameter [(4.11 +/- 0.10) mm and (3.34 +/- 0.11) mm vs. (2.88 +/- 0.08) mm, P < 0.05, respectively] and reduction in neointimal thickness [(208 +/- 17) microm and (407 +/- 25) microm vs. (448 +/- 15) microm, P < 0.05, respectively], neointimal area [(0.27 +/- 0.09) mm2 and (0.38 +/- 0.01) mm2 vs. (0.41 +/- 0.02) mm2, P < 0.05, respectively] and restenosis rate [(28.1 +/- 2.7)% and (36.8 +/- 2.2)% vs. (40.1 +/- 2.7)%, P < 0.05, respectively] compared with control group. Collagen I, III mRNA and TGF-beta1, Smad2 protein levels were significantly elevated in control group, ANG-(1-7) group and ANG-(1-7) +A-779 group compared to sham group (P < 0.01 or P < 0.05) and reduced in ANG-(1-7) group compared to control group (all P < 0.05). Co-treatment with A-779 reversed the inhibitory action of ANG-(1-7). Plasma levels of ANG II postangioplasty were similar in control and ANG-(1-7) group and both were significantly higher than preoperation levels.

CONCLUSIONANG-(1-7) attenuates postangioplasty collagen synthesis in rabbits possibly through down-regulating the expression of TGF-beta1 and inhibiting the activation of Smad2 pathway.

Angiotensin I ; pharmacology ; Animals ; Aorta, Abdominal ; drug effects ; metabolism ; pathology ; Collagen Type I ; metabolism ; Collagen Type III ; metabolism ; Fibrosis ; metabolism ; Muscle, Smooth, Vascular ; metabolism ; Peptide Fragments ; pharmacology ; Rabbits ; Signal Transduction ; Smad2 Protein ; metabolism ; Transforming Growth Factor beta1 ; metabolism

BACKGROUNDRepeated attacks of bronchial asthma lead to different degrees of airway remodeling, the mechanism of which is not yet clear. Some evidences indicate that it is related to the excessive expression of some growth promotion factors. Angiotensin II is a polypeptide that may be involved in airway remodeling. To evaluate its role in airway remodeling in asthma, we observed the effects of an angiotensin II type 1 receptor antagonist (valsartan) on the expression of collagen III, collagen V, and transforming growth factor beta1 (TGF-beta1) mRNA and protein in the airway walls of sensitized rats.

METHODSForty Wistar rats were randomly divided into 5 groups: control group, sensitized group, and valsartan groups 1, 2, and 3. The rats in the sensitized group and in valsartan groups 1, 2, and 3 were sensitized and challenged with ovalbumin. Rats in control group were sensitized and challenged with 0.9% NaCl. Rats from valsartan groups 1, 2, and 3 were drenched with valsartan (10 microg, 20 microg, or 30 microg, respectively) at the time of the ovalbumin challenges. The expression of collagen III, collagen V, and TGF-beta1 protein were detected using immunohistochemical method in combination with image analysis methods. The expression of TGF-beta1 mRNA was detected by in situ hybridization.

RESULTSThe expression in the airways of collagen III and collagen V was significantly higher in rats from the sensitized group (7.73 +/- 0.81, 1.34 +/- 0.28) and from valsartan groups 1, 2, and 3 (5.73 +/- 0.64, 1.13 +/- 0.15; 4.96 +/- 0.51, 0.98 +/- 0.08; 4.43 +/- 0.35, 0.93 +/- 0.06, respectively) than those in the control group (2.65 +/- 0.38, 0.67 +/- 0.08, P < 0.05). In addition, collagen levels were significantly lower in valsartan groups 1, 2, and 3 than those from the sensitized group (P < 0.05). The expression of TGF-beta1 mRNA and protein in the airways was significantly higher in rats from the sensitized group (20.49% +/- 3.46%, 29.73% +/- 3.25%) and from valsartan groups 1, 2, and 3 (16.47% +/- 1.94%, 19.41% +/- 1.87%; 14.38% +/- 1.58%, 18.29% +/- 1.43%; 12.96% +/- 1.73%, 18.63% +/- 1.11%, respectively) than that from the control group (7.84% +/- 1.61%, 5.63% +/- 1.07%, P < 0.05). TGF-beta1 mRNA and protein levels were significantly lower in valsartan groups 1, 2, and 3 than that in the sensitized group (P < 0.05).

CONCLUSIONSAngiotensin II receptor antagonist valsartan can suppress synthesis of collagen III and collagen V by downregulating TGF-beta1 mRNA and protein expression. Valsartan can decrease airway remodeling and could play a role in asthma therapy.

Angiotensin Receptor Antagonists ; Animals ; Asthma ; physiopathology ; Bronchi ; metabolism ; Collagen Type III ; analysis ; Collagen Type V ; analysis ; Immunization ; Male ; Ovalbumin ; RNA, Messenger ; analysis ; Random Allocation ; Rats ; Rats, Wistar ; Tetrazoles ; pharmacology ; Transforming Growth Factor beta ; analysis ; Valine ; analogs & derivatives ; pharmacology ; Valsartan

Angiotensin II Type 1 Receptor Blockers ; therapeutic use ; Animals ; Benzimidazoles ; therapeutic use ; Hypertension ; blood ; drug therapy ; Male ; Nitric Oxide ; blood ; Nitric Oxide Synthase Type III ; blood ; Random Allocation ; Rats ; Rats, Inbred SHR ; Tetrazoles ; therapeutic use ; Urotensins ; blood

OBJECTIVETo explore the effect of erythropoietin (EPO) on angiotensin II (AngII) induced neonatal rat cardiomyocyte hypertrophy and the association with PI3K/Akt-eNOS signaling pathway.

METHODSCardiomyocytes were isolated from new-born Sprague-Dawley rats and stimulated by AngII in vitro. The cell surface area and mRNA expression of atrial natriuretic factor (ANF) of cardiomyocytes were determined in the presence and absence of various concentrations of EPO, phosphatidylinositol 3'-kinase (PI3K) inhibitor LY294002 and nitric oxide synthase (NOS) inhibitor L-NAME. Intracellular signal molecules, such as Akt, phosphorylated Akt, eNOS and phosphorylated eNOS protein expressions were detected by western blot. Nitric oxide (NO) level in the supernatant of cultured cardiomyocytes was assayed by NO assay kit.

RESULTSEPO (20 U/ml) significantly inhibited AngII induced cardiomyocyte hypertrophy as shown by decreased cell surface area and ANF mRNA expression (all P < 0.05). EPO also activated Akt and enhanced the expression of eNOS and its phosphorylation (all P < 0.05), increased the NO production (P < 0.01). These effects could be partially abolished by cotreatment with LY294002 or L-NAME (all P < 0.05).

CONCLUSIONEPO attenuates AngII induced cardiomyocytes hypertrophy via activating PI3K-Akt-eNOS pathway and promoting NO production.

Angiotensin II ; pharmacology ; Animals ; Cell Enlargement ; Cells, Cultured ; Erythropoietin ; pharmacology ; Myocytes, Cardiac ; drug effects ; metabolism ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction