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Gómez Del Val A, Contreras C, Muñoz M, Sáenz-Medina J, Mohamed M, Rivera L, Sánchez A, Prieto D. Activation of mitoK ATP channels induces penile vasodilation and inhibits mitochondrial respiration and ROS production: Role of NO. Free Radic Biol Med 2024; 217:15-28. [PMID: 38522485 DOI: 10.1016/j.freeradbiomed.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/17/2024] [Accepted: 03/12/2024] [Indexed: 03/26/2024]
Abstract
OBJECTIVE Mitochondrial ATP-sensitive K+ (mitoKATP) channels are involved in neuronal and cardiac protection from ischemia and oxidative stress. Penile erection is a neurovascular event mediated by relaxation of the erectile tissue via nitric oxide (NO) released from nerves and endothelium. In the present study, we investigated whether mitoKATP channels play a role in the control of penile vascular tone and mitochondrial dynamics, and the involvement of NO. METHODS The effect of the selective mitoKATP activator BMS191095 was examined on vascular tone, on mitochondrial bioenergetics by real-time measurements with Agilent Seahorse and on ROS production by MitoSOX fluorescence in freshly isolated microarteries. RESULTS BMS191095 and diazoxide relaxed penile arteries, BMS191095 being one order of magnitude more potent. BMS191095-induced relaxations were reduced by mechanical endothelium removal and by inhibitors of the nitric oxide synthase (NOS) and PI3K enzymes. The NO-dependent component of the relaxation to BMS191095 was impaired in penile arteries from insulin resistant obese rats. The blockers of mitoKATP channel 5-HD, sarcolemma KATP (sarcKATP) channel glibenclamide, and large conductance Ca2+-activated K+ (BKCa) channel iberiotoxin, inhibited relaxations to BMS191095 and to the NO donor SNAP. BMS191095 reduced the mitochondrial bioenergetic profile of penile arteries and attenuated mitochondrial ROS production. Blockade of endogenous NO impaired and exogenous NO mimicked, respectively, the inhibitory effects of BMS191095 on basal respiration and oxygen consumed for ATP synthesis. Exogenous NO exhibited dual inhibitory/stimulatory effects on mitochondrial respiration. CONCLUSIONS These results demonstrate that selective activation of mitoKATP channels causes penile vasodilation, attenuates ROS production and inhibits mitochondrial respiration in part by releasing endothelial NO. These mechanisms couple blood flow and metabolism in penile arterial wall and suggest that activation of vascular mitoKATP channels may protect erectile tissue against ischemic injury.
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Affiliation(s)
- Alfonso Gómez Del Val
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Cristina Contreras
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Mercedes Muñoz
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Javier Sáenz-Medina
- Department of Urology, Puerta de Hierro-Majadahonda University Hospital, 28222, Majadahonda, Spain
| | - Mariam Mohamed
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Luis Rivera
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Ana Sánchez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Dolores Prieto
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain.
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García-Lluch G, Peña-Bautista C, Royo LM, Baquero M, Cañada-Martínez AJ, Cháfer-Pericás C. Angiotensin II Receptor Blockers Reduce Tau/Aß42 Ratio: A Cerebrospinal Fluid Biomarkers’ Case-Control Study. Pharmaceutics 2023; 15:pharmaceutics15030924. [PMID: 36986785 PMCID: PMC10059654 DOI: 10.3390/pharmaceutics15030924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/03/2023] [Accepted: 03/03/2023] [Indexed: 03/16/2023] Open
Abstract
(1) Background: The role of antihypertensives in Alzheimer’s Disease (AD) prevention is controversial. This case-control study aims to assess whether antihypertensive medication has a protective role by studying its association with amyloid and tau abnormal levels. Furthermore, it suggests a holistic view of the involved pathways between renin-angiotensin drugs and the tau/amyloidß42 ratio (tau/Aß42 ratio); (2) Methods: The medical records of the participant patients were reviewed, with a focus on prescribed antihypertensive drugs and clinical variables, such as arterial blood pressure. The Anatomical Therapeutic Chemical classification was used to classify each drug. The patients were divided into two groups: patients with AD diagnosis (cases) and cognitively healthy patients (control); (3) Results: Age and high systolic blood pressure are associated with a higher risk of developing AD. In addition, combinations of angiotensin II receptor blockers are associated with a 30% lower t-tau/Aß42 ratio than plain angiotensin-converting enzyme inhibitor consumption; (4) Conclusions: Angiotensin II receptor blockers may play a potential role in neuroprotection and AD prevention. Likewise, several mechanisms, such as the PI3K/Akt/GSK3ß or the ACE1/AngII/AT1R axis, may link cardiovascular pathologies and AD presence, making its modulation a pivotal point in AD prevention. The present work highlights the central pathways in which antihypertensives may affect the presence of pathological amyloid and tau hyperphosphorylation.
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Affiliation(s)
- Gemma García-Lluch
- Research Group in Alzheimer Disease, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
- Cátedra DeCo MICOF-CEU UCH, Universidad Cardenal Herrera-CEU, 46115 Valencia, Spain
| | - Carmen Peña-Bautista
- Research Group in Alzheimer Disease, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
| | - Lucrecia Moreno Royo
- Cátedra DeCo MICOF-CEU UCH, Universidad Cardenal Herrera-CEU, 46115 Valencia, Spain
- Department of Pharmacy, Universidad Cardenal Herrera-CEU, CEU Universities, 46115 Valencia, Spain
| | - Miguel Baquero
- Research Group in Alzheimer Disease, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
- Cátedra DeCo MICOF-CEU UCH, Universidad Cardenal Herrera-CEU, 46115 Valencia, Spain
- Neurology Unit, Hospital Universitari i Politècnic La Fe, 46026 Valencia, Spain
| | | | - Consuelo Cháfer-Pericás
- Research Group in Alzheimer Disease, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
- Cátedra DeCo MICOF-CEU UCH, Universidad Cardenal Herrera-CEU, 46115 Valencia, Spain
- Correspondence:
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La Fuente JM, Sevilleja-Ortiz A, García-Rojo E, El Assar M, Fernández A, Pepe-Cardoso AJ, Martínez-Salamanca JI, Romero-Otero J, Rodríguez-Mañas L, Angulo J. Erectile dysfunction is associated with defective L-cysteine/hydrogen sulfide pathway in human corpus cavernosum and penile arteries. Eur J Pharmacol 2020; 884:173370. [PMID: 32712093 DOI: 10.1016/j.ejphar.2020.173370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 07/09/2020] [Accepted: 07/13/2020] [Indexed: 12/24/2022]
Abstract
H2S signaling was proposed to participate in erectile physiology. L-cysteine (CYS)/H2S pathway stimulation causes cGMP-dependent relaxation of human corpus cavernosum (HCC) and penile arteries (HPRA). The aim was to evaluate the impact of ED on CYS/H2S pathway at functional and molecular level in human penile vascular tissues. NaHS- and CYS-induced responses were evaluated in HCC and HPRA from organ donors without ED (NoED, n = 29) and from ED patients undergoing penile prosthesis insertion (n = 45). cGMP accumulation and cystathionine β-synthase and cystathionine γ-lyase expression were also determined. NaHS-induced relaxations were slightly but significantly impaired in HCC but not in HPRA from ED patients. In contrast, CYS-induced relaxations were markedly impaired in HCC (Emax 67.6 ± 4.9% vs 46.2 ± 4.6%, P < 0.01) and HPRA (Emax 80.8 ± 4.0% vs 48.1 ± 8.6%, P < 0.05) from men with ED. Impairment of CYS-induced responses was observed even after separating diabetic ED patients. In HPRA from ED patients, CYS- but not NaHS-induced vasodilation was significantly associated to endothelial function measured as vasodilatory capacity of acetylcholine (ACh) in these preparations (r2 = 0.481, P < 0.01). Impairment of CYS-induced relaxations was related to significant reduction in CYS-induced accumulation of cGMP in cavernosal tissue. Furthermore, the expression of H2S synthesizing enzymes was significantly reduced in HCC from ED patients with respect to NoED. This was confirmed by immunofluorescence in HCC and HPRA sections. ED involves impairment of CYS/H2S pathway in penile vascular tissues associated with decreased expression of H2S generating enzymes, CBS and CSE. These evidences support a therapeutic potential for modulation of CYS/H2S signaling in the management of ED.
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Affiliation(s)
| | | | - Esther García-Rojo
- Servicio de Urología, Hospital Universitario Doce de Octubre, Madrid, Spain
| | | | - Argentina Fernández
- Servicio de Histología-Investigación, Hospital Universitario Ramón y Cajal - IRYCIS, Madrid, Spain
| | | | | | | | | | - Javier Angulo
- Servicio de Histología-Investigación, Hospital Universitario Ramón y Cajal - IRYCIS, Madrid, Spain.
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La Fuente JM, Fernández A, Pepe-Cardoso AJ, Martínez-Salamanca JI, Louro N, Angulo J. L-cysteine/hydrogen sulfide pathway induces cGMP-dependent relaxation of corpus cavernosum and penile arteries from patients with erectile dysfunction and improves arterial vasodilation induced by PDE5 inhibition. Eur J Pharmacol 2019; 863:172675. [PMID: 31542487 DOI: 10.1016/j.ejphar.2019.172675] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/10/2019] [Accepted: 09/18/2019] [Indexed: 02/06/2023]
Abstract
The aim was to evaluate and characterize H2S-induced relaxation of human corpus cavernosum (HCC) and penile resistance arteries (HPRA) from patients with erectile dysfunction (ED). HCC and HPRA were obtained from men with ED at the time of penile prosthesis insertion. H2S-mediated relaxations were evaluated by exposing these tissues to the stable analogue, NaHS, and to the precursor of H2S, L-cysteine (CYS). The effects of NaHS and CYS were also evaluated on cGMP accumulation in HCC and on acetylcholine- and sildenafil-mediated relaxations in HCC and HPRA. NaHS consistently relaxed HPRA and HCC and more potently than human prostate and bladder. NaHS-induced relaxations in HCC and HPRA were unaffected by the ATP-sensitive K+-channel blocker, glibenclamide or the NO synthase inhibitor, L-NAME, slightly reduced by the Ca2+-activated K+-channel blocker, tetraethylammonium, and markedly inhibited by the soluble guanylyl cyclase inhibitor, ODQ. NaHS caused a cGMP increase in HCC that was inhibited by ODQ. CYS produced relaxations of HCC and HPRA that were sensitive to ODQ and to inhibition of the H2S synthesizing enzymes, cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS). CYS also increased cGMP in HCC. In contrast to NaHS, CYS-induced relaxations were prevented by endothelium removal in HPRA. Only in HPRA, treatment with CYS (30 μM) potentiated acetylcholine- and sildenafil-induced relaxations. This effect was prevented by CSE/CBS inhibition and by removing the endothelium. Exogenous and endogenous H2S relaxes HCC and HPRA from ED patients through cGMP accumulation and potentiates vasodilatory capacity of PDE5 inhibition, supporting the therapeutic potential of modulating H2S pathway.
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Affiliation(s)
| | - Argentina Fernández
- Servicio de Histología-Investigación, Unidad de Investigación Traslacional en Cardiología (UFV-IRYCIS), Hospital Universitario Ramón y Cajal, Madrid, Spain
| | | | | | - Nuno Louro
- Serviço de Urologia, Hospital Santo Antonio, Porto, Portugal
| | - Javier Angulo
- Servicio de Histología-Investigación, Unidad de Investigación Traslacional en Cardiología (UFV-IRYCIS), Hospital Universitario Ramón y Cajal, Madrid, Spain.
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Angulo J, El Assar M, Sevilleja-Ortiz A, Fernández A, Sánchez-Ferrer A, Romero-Otero J, Martínez-Salamanca JI, La Fuente JM, Rodríguez-Mañas L. Short-term pharmacological activation of Nrf2 ameliorates vascular dysfunction in aged rats and in pathological human vasculature. A potential target for therapeutic intervention. Redox Biol 2019; 26:101271. [PMID: 31302408 PMCID: PMC6626891 DOI: 10.1016/j.redox.2019.101271] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/28/2019] [Accepted: 07/04/2019] [Indexed: 12/11/2022] Open
Abstract
Oxidative stress contributes to endothelial dysfunction, a key step in cardiovascular disease development. Ageing-related vascular dysfunction involves defective antioxidant response. Nuclear factor erythroid 2-like-2 (Nrf2), orchestrates cellular response to oxidative stress. We evaluated the impact of Nrf2-activation on endothelium-dependent and H2O2-mediated vasodilations in: aorta (RA), mesenteric artery (RMA), coronary artery (RCA) and corpus cavernosum (RCC) from ageing rats and in human penile arteries (HPRA) and corpus cavernosum (HCC) from erectile dysfunction (ED) patients. Relaxant responses were evaluated in organ chambers and wire myographs. Nrf2 content and heme oxygenase-1 (HO-1) were determined by ELISA. Superoxide and Nrf2 were detected by immunofluorescence. Pharmacological activation of Nrf2 with sulforaphane (SFN) improved NO- and endothelium-derived hyperpolarizing factor-mediated endothelium-dependent vasodilation and H2O2-induced relaxation in vascular beds from aging rats. SFN-induced effects were associated with increased Nrf2 (RMA, RCA) and reduced superoxide detection in RCA. Improvement of vascular function was confirmed in HPRA and HCC from ED patients and mimicked by another Nrf2 activator, oltipraz. Nrf2 increase and superoxide reduction together with HO-1 increase by Nrf2 activation was evidenced in HCC from ED patients. PDE5 inhibitor-induced relaxations of HPRA and HCC from ED patients were enhanced by SFN. Nrf2 short-term pharmacological activation attenuates age-related impairment of endothelium-dependent and reactive oxygen species (ROS)-induced vasodilation in different rat and human vascular territories by upregulation of Nrf2-related signaling and decreased oxidative stress. In ED patients target tissues, Nrf2 potentiates the functional effect of ED conventional pharmacological therapy suggesting potential therapeutic implication.
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Affiliation(s)
- Javier Angulo
- Servicio de Histología-Investigación, Unidad de Investigación Traslacional en Cardiología (IRYCIS-UFV), Hospital Ramón y Cajal, Madrid, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Mariam El Assar
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain; Fundación para la Investigación Biomédica del Hospital Universitario de Getafe, Getafe, Spain
| | - Alejandro Sevilleja-Ortiz
- Servicio de Histología-Investigación, Unidad de Investigación Traslacional en Cardiología (IRYCIS-UFV), Hospital Ramón y Cajal, Madrid, Spain
| | - Argentina Fernández
- Servicio de Histología-Investigación, Unidad de Investigación Traslacional en Cardiología (IRYCIS-UFV), Hospital Ramón y Cajal, Madrid, Spain
| | - Alberto Sánchez-Ferrer
- Fundación para la Investigación Biomédica del Hospital Universitario de Getafe, Getafe, Spain
| | | | | | | | - Leocadio Rodríguez-Mañas
- Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain; Fundación para la Investigación Biomédica del Hospital Universitario de Getafe, Getafe, Spain; Servicio de Geriatría, Hospital Universitario de Getafe, Getafe, Spain.
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Minaz N, Razdan R, Hammock BD, Mujwar S, Goswami SK. Impact of diabetes on male sexual function in streptozotocin-induced diabetic rats: Protective role of soluble epoxide hydrolase inhibitor. Biomed Pharmacother 2019; 115:108897. [PMID: 31102913 PMCID: PMC6893866 DOI: 10.1016/j.biopha.2019.108897] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 04/07/2019] [Accepted: 04/17/2019] [Indexed: 12/31/2022] Open
Abstract
Diabetes-induced male sexual dysfunction is associated with endothelial dysfunction. Inhibition of soluble epoxide hydrolase (sEH) is known to improve endothelial function in diabetes. Therefore, we hypothesized that sEH inhibitor (sEHI), [trans-4-{4-[3-(4-trifluoromethoxyphenyl)-ureido]cyclohexyloxy}benzoic acid] / t-TUCB can restore the male sexual function in diabetic rat. After one week of administration of diabetogenic agent STZ (52 mg/kg i.p) injection, diabetic rats were treated with t-TUCB (0.1 and 0.3 mg/kg, p.o) or vehicle for 8 weeks. The sexual behaviour parameters of the animals were evaluated at the end of dosing period. The levels of testosterone and glucose in serum, and sperm were quantified. Effect of treatment on weight of reproductive organs and histopathology of penile tissue was evaluated. Diabetes had a negative effect on male sexual function, weight of sexual organs and production of sperm with a parallel decrease in the level of testosterone. The sEHI, t-TUCB, significantly preserved the sexual function and minimized an increase in the level of blood glucose in diabetic rats. It also prevented a decrease in the level of testosterone and sperm in diabetic rats, in comparison to diabetic control rats. Further, diabetes induced distortion of corpus cavernosum was attenuated by t-TUCB. Based on our findings, sEHI may delay the development of sexual dysfunction in diabetes.
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Affiliation(s)
- Nathani Minaz
- Department of Pharmacology, Al-Ameen College of Pharmacy, Bangalore, Karnataka, India
| | - Rema Razdan
- Department of Pharmacology, Al-Ameen College of Pharmacy, Bangalore, Karnataka, India
| | - Bruce D Hammock
- Department of Entomology and Nematology, and Comprehensive Cancer Center, University of California, Davis, CA, USA
| | - Somdutt Mujwar
- Institute of Pharmaceutical Research, GLA University, 17km Stone, NH-2, Mathura-Delhi Road P.O. Chaumuhan, Mathura, 281 406, Uttar Pradesh, India
| | - Sumanta Kumar Goswami
- Department of Pharmacology, Al-Ameen College of Pharmacy, Bangalore, Karnataka, India; Department of Entomology and Nematology, and Comprehensive Cancer Center, University of California, Davis, CA, USA.
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Cobo-Nuñez MY, El Assar M, Cuevas P, Sánchez-Ferrer A, Martínez-González J, Rodríguez-Mañas L, Angulo J. Haemostatic agent etamsylate in vitro and in vivo antagonizes anti-coagulant activity of heparin. Eur J Pharmacol 2018; 827:167-172. [PMID: 29555505 DOI: 10.1016/j.ejphar.2018.03.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/15/2018] [Accepted: 03/15/2018] [Indexed: 12/18/2022]
Abstract
Etamsylate is indicated for several anti-hemorrhagic indications in human and veterinary medicine. However, etamsylate has been shown to be effective only in specific hemorrhagic situations. Furthermore, mechanism of action of etamsylate is not known but recent research has shown its ability to inhibit heparin binding to several growth factors. We have evaluated the ability of etamsylate to interfere with the activities of heparin. Effects of etamsylate on vasodilatory activity of heparin were evaluated in rat aortic segments. Influence of etamsylate on anticoagulant activity of heparin was evaluated in vitro by determining prothrombin (PT) time and activated partial thromboplastin time (aPTT) in dog blood and in vivo by determining the interference of systemic and topical etamsylate on heparin-induced extension in bleeding time (BT) in rats. Despite failing to inhibit heparin-induced vasodilation of rat aorta, etamsylate significantly reduced the increase in aPTT caused by heparin (+30.4 ± 6.7% vs. +15.0 ± 2.8% for etamsylate at 100 µM, P < 0.05). Etamsylate also antagonized the anticoagulant effects driven by heparin in vivo since prevented the heparin-induced increase in BT when systemically (i.p.) administered (+94.6 ± 7.5% vs. +57.9 ± 9.2% at 10 mg/kg, P < 0.05, vs. +22.2 ± 16.8% at 30 mg/kg, P < 0.01). Additionally, topically applied etamsylate (125 mg/ml) significantly reduced heparin-induced BT increase (+102.5 ± 3.2% vs. +54.0 ± 5.8%, P < 0.01). These evidences show a pharmacological interference by etamsylate on heparin activities antagonizing pro-hemorrhagic effects of heparin in vitro and in vivo without inhibiting its vasodilatory properties. This ability could help to explain pharmacological effects of etamsylate and proposes its role for reversing pro-hemorrhagic states.
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Affiliation(s)
| | - Mariam El Assar
- Fundación para la Investigación Biomédica del Hospital Universitario de Getafe, Getafe, Spain
| | - Pedro Cuevas
- Universidad Alfonso X el Sabio, Villanueva de la Cañada, Spain
| | - Alberto Sánchez-Ferrer
- Fundación para la Investigación Biomédica del Hospital Universitario de Getafe, Getafe, Spain
| | | | - Leocadio Rodríguez-Mañas
- Fundación para la Investigación Biomédica del Hospital Universitario de Getafe, Getafe, Spain; Servicio de Geriatría, Hospital Universitario de Getafe, Getafe, Spain
| | - Javier Angulo
- Servicio de Histología-Investigación, Hospital Universitario Ramón y Cajal, Madrid, Spain.
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Comerma-Steffensen SG, Carvacho I, Hedegaard ER, Simonsen U. Small and Intermediate Calcium-Activated Potassium Channel Openers Improve Rat Endothelial and Erectile Function. Front Pharmacol 2017; 8:660. [PMID: 28993731 PMCID: PMC5619997 DOI: 10.3389/fphar.2017.00660] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 09/05/2017] [Indexed: 12/13/2022] Open
Abstract
Modulation of endothelial calcium-activated potassium (KCa) channels has been proposed as an approach to restore endothelial function. The present study investigated whether novel openers of KCa channels with small (KCa2.x) and intermediate (KCa3.1) conductance, NS309 and NS4591, improve endothelium-dependent relaxation and erectile function. Rat corpus cavernosum (CC) strips were mounted for isometric tension recording and processed for immunoblotting. Mean arterial pressure (MAP), intracavernosal pressure (ICP), and electrocardiographic (ECG) measurements were conducted in anesthetized rats. Immunoblotting revealed the presence of KCa2.3 and large KCa conductance (KCa1.1) channels in the corpus cavernosum. NS309 and NS4591 increased current in CC endothelial cells in whole cell patch clamp experiments. Relaxation induced by NS309 (<1 μM) was inhibited by endothelial cell removal and high extracellular potassium. An inhibitor of nitric oxide (NO) synthase, and blockers of KCa2.x and KCa1.1 channels, apamin and iberiotoxin also inhibited NS309 relaxation. Incubation with NS309 (0.5 μM) markedly enhanced acetylcholine relaxation. Basal erectile function (ICP/MAP) increased during administration of NS309. Increases in ICP/MAP after cavernous nerve stimulation with NS309 were unchanged, whereas NS4591 significantly improved erectile function. Administration of NS309 and NS4591 caused small changes in the electrocardiogram, but neither arrhythmic events nor prolongation of the QTc interval were observed. The present study suggests that openers of KCa2.x and KCa3.1 channels improve endothelial and erectile function. The effects of NS309 and NS4591 on heart rate and ECG are small, but will require additional safety studies before evaluating whether activation of KCa2.3 channels has a potential for treatment of erectile dysfunction.
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Affiliation(s)
- Simon G. Comerma-Steffensen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus UniversityAarhus, Denmark
- Animal Physiology, Department of Biomedical Sciences, Veterinary Sciences Faculty, Central University of VenezuelaMaracay, Venezuela
| | - Ingrid Carvacho
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus UniversityAarhus, Denmark
- Department of Biology and Chemistry, Faculty of Basic Sciences, Universidad Católica del MauleTalca, Chile
| | - Elise R. Hedegaard
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus UniversityAarhus, Denmark
| | - Ulf Simonsen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus UniversityAarhus, Denmark
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9
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Comerma-Steffensen S, Kun A, Hedegaard ER, Mogensen S, Aalkjaer C, Köhler R, Mønster Christensen B, Simonsen U. Down-regulation of K Ca2.3 channels causes erectile dysfunction in mice. Sci Rep 2017. [PMID: 28630432 PMCID: PMC5476588 DOI: 10.1038/s41598-017-04188-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Modulation of endothelial calcium-activated K+ channels has been proposed as an approach to restore arterial endothelial cell function in disease. We hypothesized that small-conductance calcium-activated K+ channels (KCa2.3 or SK3) contributes to erectile function. The research was performed in transgenic mice with overexpression (KCa2.3T/T(−Dox)) or down-regulation (KCa2.3T/T(+Dox)) of the KCa2.3 channels and wild-type C57BL/6-mice (WT). QPCR revealed that KCa2.3 and KCa1.1 channels were the most abundant in mouse corpus cavernosum. KCa2.3 channels were found by immunoreactivity and electron microscopy in the apical-lateral membrane of endothelial cells in the corpus cavernosum. Norepinephrine contraction was enhanced in the corpus cavernosum of KCa2.3T/T(+Dox)versus KCa2.3T/T(−Dox) mice, while acetylcholine relaxation was only reduced at 0.3 µM and relaxations in response to the nitric oxide donor sodium nitroprusside were unaltered. An opener of KCa2 channels, NS309 induced concentration-dependent relaxations of corpus cavernosum. Mean arterial pressure was lower in KCa2.3T/T(−Dox) mice compared with WT and KCa2.3T/T(+Dox) mice. In anesthetized mice, cavernous nerve stimulation augmented in frequency/voltage dependent manner erectile function being lower in KCa2.3T/T(+Dox) mice at low frequencies. Our findings suggest that down-regulation of KCa2.3 channels contributes to erectile dysfunction, and that pharmacological activation of KCa2.3 channels may have the potential to restore erectile function.
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Affiliation(s)
- Simon Comerma-Steffensen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark.
| | - Attila Kun
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark
| | - Elise R Hedegaard
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark
| | - Susie Mogensen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark
| | | | - Ralf Köhler
- Aragon Agency for Investigation and Development (ARAID), Translational Research Unit, Miguel Servet University Hospital, Zaragoza, Spain
| | | | - Ulf Simonsen
- Department of Biomedicine, Pulmonary and Cardiovascular Pharmacology, Aarhus University, Aarhus, Denmark
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El Assar M, Angulo J, Rodríguez-Mañas L. Oxidative stress and vascular inflammation in aging. Free Radic Biol Med 2013; 65:380-401. [PMID: 23851032 DOI: 10.1016/j.freeradbiomed.2013.07.003] [Citation(s) in RCA: 412] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 06/28/2013] [Accepted: 07/02/2013] [Indexed: 12/13/2022]
Abstract
Vascular aging, a determinant factor for cardiovascular disease and health status in the elderly, is now viewed as a modifiable risk factor. Impaired endothelial vasodilation is a early hallmark of arterial aging that precedes the clinical manifestations of vascular dysfunction, the first step to cardiovascular disease and influencing vascular outcomes in the elderly. Accordingly, the preservation of endothelial function is thought to be an essential determinant of healthy aging. With special attention on the effects of aging on the endothelial function, this review is focused on the two main mechanisms of aging-related endothelial dysfunction: oxidative stress and inflammation. Aging vasculature generates an excess of the reactive oxygen species (ROS), superoxide and hydrogen peroxide, that compromise the vasodilatory activity of nitric oxide (NO) and facilitate the formation of the deleterious radical, peroxynitrite. Main sources of ROS are mitochondrial respiratory chain and NADPH oxidases, although NOS uncoupling could also account for ROS generation. In addition, reduced antioxidant response mediated by erythroid-2-related factor-2 (Nrf2) and downregulation of mitochondrial manganese superoxide dismutase (SOD2) contributes to the establishment of chronic oxidative stress in aged vessels. This is accompanied by a chronic low-grade inflammatory phenotype that participates in defective endothelial vasodilation. The redox-sensitive transcription factor, nuclear factor-κB (NF-κB), is upregulated in vascular cells from old subjects and drives a proinflammatory shift that feedbacks oxidative stress. This chronic NF-κB activation is contributed by increased angiotensin-II signaling and downregulated sirtuins and precludes adequate cellular response to acute ROS generation. Interventions targeted to recover endogenous antioxidant capacity and cellular stress response rather than exogenous antioxidants could reverse oxidative stress-inflammation vicious cycle in vascular aging. Lifestyle attitudes such as caloric restriction and exercise training appear as effective ways to overcome defective antioxidant response and inflammation, favoring successful vascular aging and decreasing the risk for cardiovascular disease.
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Affiliation(s)
- Mariam El Assar
- Fundación para la Investigación Biomédica, Hospital Universitario de Getafe, Getafe, Spain
| | - Javier Angulo
- Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Leocadio Rodríguez-Mañas
- Fundación para la Investigación Biomédica, Hospital Universitario de Getafe, Getafe, Spain; Servicio de Geriatría, Hospital Universitario de Getafe, Getafe, Spain.
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González-Corrochano R, La Fuente J, Cuevas P, Fernández A, Chen M, Sáenz de Tejada I, Angulo J. Ca2+ -activated K+ channel (KCa) stimulation improves relaxant capacity of PDE5 inhibitors in human penile arteries and recovers the reduced efficacy of PDE5 inhibition in diabetic erectile dysfunction. Br J Pharmacol 2013; 169:449-61. [PMID: 23441682 PMCID: PMC3651669 DOI: 10.1111/bph.12143] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 01/31/2013] [Accepted: 02/17/2013] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND AND PURPOSE We have evaluated the influence of calcium-activated potassium channels (KCa ) activation on cGMP-mediated relaxation in human penile tissues from non-diabetic and diabetic patients, and on the effects of PDE5 inhibitors on erectile responses in control and diabetic rats. EXPERIMENTAL APPROACH Cavernosal tissues were collected from organ donors and from patients with erectile dysfunction (ED). Relaxations of corpus cavernosum strips (HCC) and penile resistance arteries (HPRA) obtained from these specimens were evaluated. Intracavernosal pressure (ICP) increases to cavernosal nerve electrical stimulation were determined in anaesthetized diabetic and non-diabetic rats. KEY RESULTS Concentration-dependent vasodilation to the PDE5 inhibitor, sildenafil, in HPRA was sensitive to endothelium removal, NO/cGMP pathway inhibition and KCa blockade. Accordingly, activation of KCa with NS-8 (10 μM) significantly potentiated sildenafil-induced relaxations in HPRA (EC50 0.49 ± 0.22 vs. 5.21 ± 0.63 μM). In HCC, sildenafil-induced relaxation was unaffected by KCa blockade or activation. Potentiating effects in HPRA were reproduced with an alternative PDE5 inhibitor (tadalafil) and KCa activator (NS1619) and prevented by removing the endothelium. Large-conductance KCa (BK) and intermediate-conductance KCa (IK) contribute to NS-8-induced effects and were immunodetected in human and rat penile arteries. NS-8 potentiated sildenafil-induced enhancement of erectile responses in rats. Activation of KCa recovered the impaired relaxation to sildenafil in diabetic HPRA while sildenafil completely reversed diabetes-induced ED in rats only when combined with KCa activation. CONCLUSIONS AND IMPLICATIONS Activation of KCa improves vasodilatory capacity of PDE5 inhibitors in diabetic and non-diabetic HPRA, resulting in the recovery of erectile function in diabetic rats. These results suggest a therapeutic potential for KCa activation in diabetic ED.
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Affiliation(s)
- R González-Corrochano
- Servicio de Histología-Investigación, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
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12
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Király I, Pataricza J, Bajory Z, Simonsen U, Varro A, Papp JG, Pajor L, Kun A. Involvement of large-conductance Ca(2+) -activated K(+) channels in both nitric oxide and endothelium-derived hyperpolarization-type relaxation in human penile small arteries. Basic Clin Pharmacol Toxicol 2013; 113:19-24. [PMID: 23414060 DOI: 10.1111/bcpt.12059] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/28/2013] [Indexed: 12/01/2022]
Abstract
Large-conductance Ca(2+) -activated K(+) channels (BKC a ), located on the vascular smooth muscle, play an important role in regulation of vascular tone. In penile corpus cavernosum tissue, opening of BKC a channels leads to relaxation of corporal smooth muscle, which is essential during erection; however, there is little information on the role of BKC a channels located in penile vascular smooth muscle. This study was designed to investigate the involvement of BKC a channels in endothelium-dependent and endothelium-independent relaxation of human intracavernous penile arteries. In human intracavernous arteries obtained in connection with transsexual operations, change in isometric force was recorded in microvascular myographs, and endothelium-dependent [nitric oxide (NO) and endothelium-derived hyperpolarization (EDH)-type] and endothelium-independent (NO-donor) relaxations were measured in contracted arteries. In penile small arteries contracted with phenylephrine, acetylcholine evoked NO- and EDH-type relaxations, which were sensitive to iberiotoxin (IbTX), a selective blocker of BKC a channels. Iberiotoxin also inhibited relaxations induced by a NO-donor, sodium nitroprusside. NS11021, a selective opener of BKC a channels, evoked pronounced relaxations that were inhibited in the presence of IbTX. NS13558, a BKC a -inactive analogue of NS11021, failed to relax human penile small arteries. Our results show that BKC a channels are involved in both NO- and EDH-type relaxation of intracavernous penile arteries obtained from healthy men. The effect of a selective opener of BKC a channels also suggests that direct activation of the channel may be an advantageous approach for treatment of impaired endothelium-dependent relaxation often associated with erectile dysfunction.
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Affiliation(s)
- István Király
- Department of Urology, University of Szeged, Szeged, Hungary
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Javadzadeh A, Ghorbanihaghjo A, Adl FH, Andalib D, Khojasteh-Jafari H, Ghabili K. Calcium dobesilate reduces endothelin-1 and high-sensitivity C-reactive protein serum levels in patients with diabetic retinopathy. Mol Vis 2013; 19:62-8. [PMID: 23335852 PMCID: PMC3548576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 01/08/2013] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To determine the benefits of calcium dobesilate (CaD) administration on endothelial function and inflammatory status in patients with diabetic retinopathy through measurement of serum levels of endothelin-1 and high-sensitivity C-reactive protein (hsCRP). METHODS In a double-blind, randomized clinical trial, 90 patients with either severe nonproliferative or proliferative diabetic retinopathy and with blood glucose level of 120-200 mg/dl were randomly allocated to treatment with either CaD tablets (500 mg daily) or placebo for 3 months. Visual acuity, intraocular pressure, and macular status were performed before the study. The serum levels of endothelin-1 and hsCRP were evaluated in both groups before and at the third month of the trial. RESULTS The median serum level of hsCRP significantly differed between the groups 3 months following the CaD or placebo administration (2.2 mg/l in the CaD group versus 3.7 mg/l in the placebo group, p=0.01). The mean endothelin-1 serum level was 0.69±0.32 pg/ml in the CaD group and 0.86±0.30 pg/ml in the placebo group (p=0.01). Furthermore, in the CaD group, the serum levels of both endothelin-1 and hsCRP were significantly decreased 3 months after administration of CaD (p<0.001). CONCLUSIONS Administration of the CaD in the patients with diabetic retinopathy may reduce the serum levels of endothelin-1 and hsCRP. This might imply amelioration of the endothelial function and inflammatory status following CaD therapy in these patients.
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Affiliation(s)
- Alireza Javadzadeh
- Nikookari Eye Hospital, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Amir Ghorbanihaghjo
- Drug Applied Res earch Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Farzad Hami Adl
- Nikookari Eye Hospital, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Dima Andalib
- Nikookari Eye Hospital, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Kamyar Ghabili
- Physical Medicine and Rehabilitation Research Center, Tabriz University of Medical Sciences, Tabriz, Iran,Young Researchers Club, Tabriz Branch, Islamic Azad University, Tabriz, Iran
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Bivalacqua TJ, Usta MF, Champion HC, Kadowitz PJ, Hellstrom WJG. Endothelial Dysfunction in Erectile Dysfunction: Role of the Endothelium in Erectile Physiology and Disease. ACTA ACUST UNITED AC 2013; 24:S17-37. [PMID: 14581492 DOI: 10.1002/j.1939-4640.2003.tb02743.x] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Trinity J Bivalacqua
- Department of Urology, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
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El Assar M, Angulo J, Vallejo S, Peiró C, Sánchez-Ferrer CF, Rodríguez-Mañas L. Mechanisms involved in the aging-induced vascular dysfunction. Front Physiol 2012; 3:132. [PMID: 22783194 PMCID: PMC3361078 DOI: 10.3389/fphys.2012.00132] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 04/20/2012] [Indexed: 12/25/2022] Open
Abstract
Vascular aging is a key process determining health status of aged population. Aging is an independent cardiovascular risk factor associated to an impairment of endothelial function, which is a very early and important event leading to cardiovascular disease. Vascular aging, formerly being considered an immutable and inexorable risk factor, is now viewed as a target process for intervention in order to achieve a healthier old age. A further knowledge of the mechanisms underlying the age-related vascular dysfunction is required to design an adequate therapeutic strategy to prevent or restore this impairment of vascular functionality. Among the proposed mechanisms that contribute to age-dependent endothelial dysfunction, this review is focused on the following aspects occurring into the vascular wall: (1) the reduction of nitric oxide (NO) bioavailability, caused by diminished NO synthesis and/or by augmented NO scavenging due to oxidative stress, leading to peroxynitrite formation (ONOO(-)); (2) the possible sources involved in the enhancement of oxidative stress; (3) the increased activity of vasoconstrictor factors; and (4) the development of a low-grade pro-inflammatory environment. Synergisms and interactions between all these pathways are also analyzed. Finally, a brief summary of some cellular mechanisms related to endothelial cell senescence (including telomere and telomerase, stress-induced senescence, as well as sirtuins) are implemented, as they are likely involved in the age-dependent endothelial dysfunction, as well as in the lower vascular repairing capacity observed in the elderly. Prevention or reversion of those mechanisms leading to endothelial dysfunction through life style modifications or pharmacological interventions could markedly improve cardiovascular health in older people.
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Affiliation(s)
- Mariam El Assar
- Fundación para la Investigación Biomédica, Hospital Universitario de Getafe Madrid, Spain
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Morton JS, Rueda-Clausen CF, Davidge ST. Flow-mediated vasodilation is impaired in adult rat offspring exposed to prenatal hypoxia. J Appl Physiol (1985) 2011; 110:1073-82. [DOI: 10.1152/japplphysiol.01174.2010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is now a demonstrated association between low birth weight and increased mortality later in life. Changes in fetal development may program the cardiovascular system and lead to an increased risk of cardiovascular diseases later in life. In addition, aging is a risk factor for vascular endothelial-dependent dysfunction. However, the impact of being born intrauterine growth restricted (IUGR) on the normal aging mechanisms of vascular dysfunction is not clear. We hypothesized that IUGR would cause changes in vascular function that would affect the mechanisms of flow-induced vasodilation later in life in an age- or sex-dependent manner. To create an IUGR model, pregnant Sprague-Dawley rats were placed in a hypoxic (11.5% O2) or control (room air, 21% O2) environment from days 15 to 21 of pregnancy. Both male and female offspring were investigated at 4 or 12 mo of age. Vascular function was assessed in small mesenteric arteries using flow-induced vasodilation, a physiological stimuli of vasodilation, in a pressure myograph. Flow-induced vasodilation was unaffected at a young age, but was significantly reduced in aging IUGR compared with aging controls ( P < 0.05). Underlying vasodilator mechanisms were altered such that nitric oxide-mediated vasodilation was abolished in both young adult and aging IUGR males and females and in aging control females ( P > 0.05). Endothelium-derived hyperpolarizing factor-mediated vasodilation was maintained in all groups ( P < 0.01). A change in the mechanisms of vasodilation occurring at an earlier age in IUGR offspring may predispose them to develop cardiovascular diseases as an aging adult.
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Affiliation(s)
- J. S. Morton
- Departments of 1Obstetrics and Gynaecology and
- Women and Children's Health Research Institute and the Cardiovascular Research Centre, Edmonton, Alberta, Canada
| | - C. F. Rueda-Clausen
- Physiology, University of Alberta, and
- Women and Children's Health Research Institute and the Cardiovascular Research Centre, Edmonton, Alberta, Canada
| | - S. T. Davidge
- Departments of 1Obstetrics and Gynaecology and
- Physiology, University of Alberta, and
- Women and Children's Health Research Institute and the Cardiovascular Research Centre, Edmonton, Alberta, Canada
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Reduced expression of SK3 and IK1 channel proteins in the cavernous tissue of diabetic rats. Asian J Androl 2010; 12:599-604. [PMID: 20364152 DOI: 10.1038/aja.2009.97] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The small (SK3) and intermediate (IK1) conductance calcium-activated potassium channels could have key roles in the endothelium-dependent hyperpolarization factor pathway, which is believed to contribute to normal penile erection function. We aimed to investigate the expression of SK3 and IK1 in diabetic rodents. The experimental diabetes model was induced in 8-week-old male Sprague-Dawley rats (250-300 g) by a single administration of streptozotocin. Both the diabetes mellitus group (DM group, n = 20) and the control group (NDM group, n = 10) were injected with a low dose of apomorphine to allow for the measurement and comparison of the corresponding penile erections. The mRNA and protein expression levels of SK3 and IK1 were measured by reverse transcription polymerase chain reaction and western blot, respectively. Erectile function was significantly decreased in the DM group compared with control group (P < 0.05). The mRNA and protein expression levels of SK3 and IK1 were reduced in the cavernous tissue of diabetic rats compared with the control group (P < 0.05). Diabetes inhibits mRNA and protein expression of both SK3 and IK1 in the cavernous tissue of diabetic rats. This could play a key role in the development of erectile dysfunction in diabetic rats.
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Angulo J, Wright HM, Cuevas P, González-Corrochano R, Fernández A, Cuevas B, La Fuente JM, Gupta S, Sáenz de Tejada I. Nebivolol dilates human penile arteries and reverses erectile dysfunction in diabetic rats through enhancement of nitric oxide signaling. J Sex Med 2010; 7:2681-97. [PMID: 20214719 DOI: 10.1111/j.1743-6109.2010.01710.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
INTRODUCTION Traditional beta-blockers have sometimes been associated with erectile dysfunction (ED). Nebivolol is a cardioselective β(1)-adrenoceptor antagonist that promotes vasodilation through a nitric oxide (NO)-dependent mechanism. AIM We evaluated the effects of nebivolol on the NO/cyclic guanosine monophosphate (cGMP) signaling pathway, on erectile function and dysfunction, and in human penile vascular tissues. METHODS Erectile response to cavernosal nerve electrical stimulation in control and diabetes-induced ED rats were evaluated, along with serum nitrite/nitrate (NOx) concentration and plasma/tissue cGMP levels. Endothelium-dependent and sildenafil-induced relaxation of isolated human corpus cavernosum (HCC) and human penile resistance arteries (HPRA) were also determined. MAIN OUTCOME MEASURES The effects of nebivolol on erectile function and dysfunction and on NO/cGMP-mediated responses. RESULTS Treatment with nebivolol significantly potentiated erectile response in control rats, regardless of its effects on blood pressure. Nebivolol increased NOx and plasma cGMP by 3-fold and 2.75-fold, respectively, and significantly augmented the elevation of plasma cGMP produced by sildenafil. Nebivolol enhanced endothelium-dependent and sildenafil-induced relaxations of HCC tissue, and produced endothelium-dependent vasodilation of HPRA. Nebivolol, but not atenolol, significantly improved erectile response in diabetic rats (51.6%, 53.2%, and 87.1% of response at 3 Hz in nondiabetic rats, for vehicle-treated, atenolol-treated, and nebivolol-treated diabetic rats, respectively); after sildenafil administration, ED was completely reversed in nebivolol-treated diabetic rats (69.6% and 112% for diabetic rats treated with sildenafil and nebivolol plus sildenafil, respectively). Accordingly, nebivolol restored systemic NOx levels and cGMP content in penile tissue from these animals. CONCLUSIONS Nebivolol in vivo activated the NO/cGMP pathway, enhanced erectile response and reversed ED in diabetic rats. Moreover, nebivolol in vitro potentiated NO/cGMP-mediated relaxation of human erectile tissues. These effects may account for the low incidence of ED in nebivolol-treated hypertensive patients. Nebivolol therefore may have utility in the treatment of ED, particularly ED associated with diabetes.
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Affiliation(s)
- Javier Angulo
- Departamento de Investigación, Hospital Ramón y Cajal, Madrid, Spain.
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Angulo J, González-Corrochano R, Cuevas P, Fernández A, La Fuente JM, Rolo F, Allona A, Sáenz de Tejada I. Diabetes exacerbates the functional deficiency of NO/cGMP pathway associated with erectile dysfunction in human corpus cavernosum and penile arteries. J Sex Med 2009; 7:758-68. [PMID: 19912487 DOI: 10.1111/j.1743-6109.2009.01587.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Diabetic men with erectile dysfunction (ED) are less responsive to therapy with type 5 phosphodiesterase (PDE5) inhibitors. Although an impairment of the nitric oxide (NO)/cyclic guanosin-monophosphate (cGMP) pathway has been shown in diabetic ED vs. non-diabetic ED, the functionality of NO/cGMP pathway in non-diabetic and diabetic ED patients with respect to non-ED patients has not been established. AIM The aim of this study is to evaluate the function of NO/cGMP signalling in human erectile tissues from ED patients exploring the added impact of diabetes. METHODS Corpus cavernosum strips (human corpus cavernosum [HCC]) and penile resistance arteries (HPRA) were collected from penile specimens from organ donors (OD) and from diabetic and non-diabetic men with ED undergoing penile prosthesis implantation. MAIN OUTCOME MEASURES Relaxations to acetylcholine, electrical field stimulation, sodium nitroprusside, and sildenafil were evaluated in phenylephrine-contracted HCC and norepinephrine-contracted HPRA. cGMP content in HCC was also determined. RESULTS The impairment of endothelium-dependent relaxation in HCC and HPRA from ED patients was exacerbated by diabetes (E(max) 76.1, 62.9, and 49.3% in HCC and 73.1, 59.8, and 46.0% in HPRA from OD, non-diabetic and diabetic ED, respectively). Hypertension, hypercholesterolemia, or aging did not exert a further impairment of endothelial relaxation among ED patients. Diabetes also causes a further impairment of neurogenic relaxation in HCC and HPRA. The basal and stimulated content of cGMP in HCC was significantly decreased in patients with ED, but specially reduced in diabetic patients. Diabetes clearly impaired PDE5 inhibitor-induced vasodilation of HPRA from ED patients. CONCLUSIONS ED is related to impaired vasodilation, reduced relaxant capacity, and diminished cGMP content in penile tissue. These alterations are more severe in diabetes and accompany reduced relaxant efficacy of PDE5 inhibition. Thus, an exacerbated reduction of nitric oxide/cGMP signaling could be responsible for ED in diabetic men and would explain their reduced response to treatment.
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Affiliation(s)
- Javier Angulo
- Departamento de Investigación, Hospital Ramón y Cajal, Madrid, Spain.
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Angulo J, Peiró C, Cuevas P, Gabancho S, Fernández A, González-Corrochano R, La Fuente JM, Baron AD, Chen KS, De Tejada IS. The Novel Antioxidant, AC3056 (2,6-di-t-butyl-4-((Dimethyl-4-Methoxyphenylsilyl)Methyloxy)Phenol), Reverses Erectile Dysfunction in Diabetic Rats and Improves NO-mediated Responses in Penile Tissue from Diabetic Men. J Sex Med 2009; 6:373-87. [DOI: 10.1111/j.1743-6109.2008.01088.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Videla S, Villoria J, Sust M, Drábek F, Všetička J, Pavlik I, Kawaciuk I, Louda M, García C, Angulo J, Sáenz de Tejada Í. Calcium Dobesilate for the Treatment of Erectile Dysfunction in Men with Diabetes Mellitus. Basic Clin Pharmacol Toxicol 2008; 103:360-6. [DOI: 10.1111/j.1742-7843.2008.00305.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kun A, Kiraly I, Pataricza J, Marton Z, Krassoi I, Varro A, Simonsen U, Papp JG, Pajor L. C-Type Natriuretic Peptide Hyperpolarizes and Relaxes Human Penile Resistance Arteries. J Sex Med 2008; 5:1114-1125. [DOI: 10.1111/j.1743-6109.2008.00775.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Yousif MHM, Benter IF. Role of cytochrome P450 metabolites of arachidonic acid in regulation of corporal smooth muscle tone in diabetic and older rats. Vascul Pharmacol 2007; 47:281-7. [PMID: 17855173 DOI: 10.1016/j.vph.2007.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Revised: 08/07/2007] [Accepted: 08/07/2007] [Indexed: 11/25/2022]
Abstract
This study examined the role of cytochrome P450 (CYP) metabolites of arachidonic acid (AA) to rat corporal smooth muscle tone. 11, 12-Epoxyeicosatrienoic acid (EET) (10(-11)-10(-6 )M) produced dose-dependent relaxation of rat (control; 10 weeks old) corpus cavernosum with a pD(2) value of 8.8+/-0.2 and a maximal relaxation of 80+/-9%, whereas 20-hydroxyeicosatetraenoic (20-HETE) did not have an effect. EET-mediated relaxation of corpus cavernosum was attenuated by 71+/-3%, 55+/-2%, 53+/-5% and 84+/-3% in the presence of nitro-L-arginine methyl ester (L-NAME) (10(-4) M), an inhibitor of nitric oxide (NO) synthase, iberiotoxin (5 x 10(-8) M), an inhibitor of calcium-activated potassium (BK) channels, glibenclamide (10(-5) M), an inhibitor of ATP-sensitive K(+) channels or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (10(-5) M), an inhibitor of soluble guanylyl cyclase, respectively. EET-mediated relaxation of rat corpus cavernosum was significantly less in the streptozotocin (STZ)-treated (diabetic) and 30 weeks old (older) animals compared to control. Carbachol (10(-9)-10(-4) M)-induced relaxation was significantly reduced whereas phenylephrine (PE) (10(-9)-5 x 10(-3) M)-induced contraction was significantly increased in the cavernosum strips from old and diabetic rats compared to the control. Pre-incubation of the cavernosum strips obtained from control, older or diabetic rats with N-hydroxy-N'-(4-butyl-2-methyl-phenyl)-formamidine (HET0016), a selective inhibitor of 20-HETE synthesis, or 1-cyclohexyl-3-dodecyl urea (CDU), a specific inhibitor of soluble epoxide hydrolase (sEH) resulted in a significant attenuation of PE-induced contraction and improvement in carbachol-induced relaxation. We conclude that 11, 12-EET-induced relaxation of the rat corpus cavernosum involves activation of cGMP/NO pathway as well as activation of ATP-sensitive K(+) channels and BK channels. These results also suggest that inhibition of 20-HETE production or reduction of EET inactivation may have therapeutic potential to prevent erectile dysfunction associated with diabetes and aging.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/metabolism
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Aging/metabolism
- Animals
- Arachidonic Acid/metabolism
- Arachidonic Acid/pharmacology
- Cytochrome P-450 Enzyme System/metabolism
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/physiopathology
- Dose-Response Relationship, Drug
- Hydroxyeicosatetraenoic Acids/metabolism
- Hydroxyeicosatetraenoic Acids/pharmacology
- In Vitro Techniques
- KATP Channels/physiology
- Large-Conductance Calcium-Activated Potassium Channels/physiology
- Male
- Muscle Contraction/drug effects
- Muscle Relaxation/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Penis/drug effects
- Penis/metabolism
- Penis/physiopathology
- Rats
- Rats, Wistar
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Affiliation(s)
- Mariam H M Yousif
- Department of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, Kuwait
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Abstract
Recent experimental evidence suggests that arterial insufficiency precedes the structural and functional changes in corpora cavernosa (CC) leading to organic erectile dysfunction (ED). The present review gives an overview of the physiological factors involved in the regulation of penile vasculature. Sympathetic nerves maintain flaccidity and tonically released noradrenaline induces vasoconstriction of both arteries and veins through alpha(1)- and alpha(2)-postsynaptic receptors and downregulates its own release and that of nitric oxide (NO) through alpha(2)-presynaptic receptors. The sympathetic cotransmitter neuropeptide Y (NPY) modulates noradrenergic vasoconstriction in penile small arteries by both enhancing and depressing noradrenaline contractions through Y(1)- and Y(2)-postsynaptic and a NO-independent atypical endothelial receptor, respectively. Activation of alpha(1)-adrenoceptors involves both Ca(2+) influx through L-type and receptor-operated Ca(2+) channels (ROC) and Ca(2+) sensitization mechanisms mediated by protein kinase C (PKC), tyrosine kinases (TKs) and Rho kinase (RhoK). In addition, RhoK can regulate Ca(2+) entry in penile arteries upon receptor stimulation. Vasodilatation of penile arteries and large veins during erection is mediated by neurally released NO. The subsequent increased arterial inflow to the cavernosal sinoids and shear stress on the endothelium lining penile arteries activates endothelial NO production through Akt phosphorylation of endothelial NO synthase (eNOS). NO stimulates guanylate cyclase and increased cyclic guanin 3'-monophosphate (cGMP) levels in turn activate protein kinase G (PKG), which enhances K(+) efflux through Ca(2+)-activated (K(Ca)) and voltage-dependent Ca(2+) (K(v)) channels in penile arteries and veins, respectively. PKG-mediated decrease in Ca(2+) sensitivity and its regulation by RhoK remains to be clarified in penile vasculature. Phosphodiesterase type 5 (PDE5) inhibitors are potent vasodilators of penile resistance arteries and increase the content and effects of basally released endothelial NO. Endothelium-dependent relaxations of penile small arteries also include an endothelium-derived hyperpolarizing factor (EDHF)-type response, which is impaired in diabetes and hypertension-associated ED. Locally produced contractile and relaxant prostanoids regulate penile venous and arterial tone, respectively. The latter activates prostaglandin I (IP) and prostaglandin E (EP) receptors coupled to adenylate cyclase and to the increase of cyclic adenosine monophosphate (cAMP) levels, which in turn stimulates K(+) efflux through ATP-sensitive K(+) (K(ATP)) channels. There is a crosstalk between the cGMP and cAMP signaling pathways in penile small arteries. Relevant issues such as the mechanisms underlying the excitation-secretion coupling of the endothelial cells, as well as those involved in cell proliferation and vascular remodeling of the penile vasculature remain to be elucidated. In addition, only few studies have investigated the changes in structure and function of penile arteries in cardiovascular risk situations leading to ED.
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Affiliation(s)
- D Prieto
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain.
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25
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Morton JS, Jackson VM, Daly CJ, McGrath JC. Endothelium Dependent Relaxation in Rabbit Genital Resistance Arteries is Predominantly Mediated by Endothelial-Derived Hyperpolarizing Factor in Females and Nitric Oxide in Males. J Urol 2007; 177:786-91. [PMID: 17222682 DOI: 10.1016/j.juro.2006.09.072] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Indexed: 11/29/2022]
Abstract
PURPOSE In nongenital arteries a sex difference has been postulated in the dominant endothelium-derived relaxant factor(s), eg nitric oxide, prostacyclin or endothelial-derived hyperpolarizing factor. Knowledge of endothelium-derived relaxant factor mechanisms in genital tissues could influence the development of novel treatments for sexual dysfunction. We compared nitric oxide and endothelial-derived hyperpolarizing factor contributions to acetylcholine induced relaxation in the genital arteries of the 2 sexes. MATERIALS AND METHODS Male dorsal and cavernous penile arteries, and female extravaginal and intravaginal arteries from New Zealand White rabbits were studied. Acetylcholine concentration-vasodilator response curves were constructed in the presence of the nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester, K(+) channel blockers (apamin and charybdotoxin) or a combination. Indomethacin was present throughout to exclude prostacyclins. RESULTS Extravaginal artery relaxation was predominantly endothelial-derived hyperpolarizing factor induced. Apamin plus charybdotoxin decreased maximal relaxations from a mean +/- SEM of 77% +/- 4% to 23% +/- 3% in 6 preparations (p <0.01). However, nitric oxide and endothelial-derived hyperpolarizing factor contributed to overall function. Dorsal artery relaxation was largely nitric oxide induced. Nomega-nitro-L-arginine methyl ester decreased maximal relaxations from 90% +/- 3% to 41% +/- 9% (p <0.001) with no endothelial-derived hyperpolarizing factor involvement (p >0.05). In cavernous and intravaginal arteries nitric oxide and endothelial-derived hyperpolarizing factor contributed to acetylcholine induced relaxation, while nitric oxide predominated. Blocking nitric oxide synthase or K(+) channels indicated that myogenic tone and constitutive activity of endothelium-derived relaxant factors were present. Vasodilator nerve mediated responses were influenced by each with the former more effective. CONCLUSIONS Vaginal inflow arteries showed a dominance of endothelial-derived hyperpolarizing factor, contrasting with nitric oxide in penile arteries. Penile arteries followed the trend that endothelial-derived hyperpolarizing factor involvement increased with decreasing vessel caliber, while the reverse was demonstrated in female arteries.
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Sáenz de Tejada I, Angulo J, Cellek S, González-Cadavid N, Heaton J, Pickard R, Simonsen U. Physiology of erectile function. J Sex Med 2006; 1:254-65. [PMID: 16422955 DOI: 10.1111/j.1743-6109.04038.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
INTRODUCTION There are numerous investigations concerning the balance and interactions between relaxant and contractile factors regulating penile smooth muscle (arterial and trabecular) tone, the determinant of penile flaccidity or erection. Enhanced knowledge of erectile physiology may improve management of men with erectile dysfunction. Aim. To provide state-of-the-art knowledge on the physiology of erectile function. METHODS An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees. Committee members established specific objectives and scopes for various male and female sexual medicine topics. The recommendations concerning state-of-the-art knowledge in the respective sexual medicine topic represent the opinion of experts from five continents developed in a process over a two-year period. Concerning the physiology of erectile function and pathophysiology of erectile dysfunction committee, there were seven experts from five countries. MAIN OUTCOME MEASURE Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate. RESULTS Key roles in the mechanism determining the tone of penile smooth muscle are played by the rise of the intracellular concentration of free calcium and the sensitivity of the contractile machinery to calcium, endothelial health, endothelium-derived nitric oxide, endothelium-derived hyperpolarizing factor (EDHF), neuronal nitric oxide, cyclic guanosine monophosphate-dependent protein kinase and phosphodiesterase type 5. CONCLUSIONS A number of new mechanisms have been identified for the local regulation of penile smooth muscle contractility and therefore penile erection. Molecules participating in these pathways can be considered targets for the development of new treatments to treat erectile dysfunction.
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Jin L, Foss CE, Zhao X, Mills TM, Wang MH, McCluskey LP, Yaddanapud GSS, Falck JR, Imig JD, Webb RC. Cytochrome P450 epoxygenases provide a novel mechanism for penile erection. FASEB J 2006; 20:539-41. [PMID: 16415108 DOI: 10.1096/fj.05-4341fje] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Erectile dysfunction (ED) is estimated to affect more than 30 million American men and 152 million men worldwide. Therapeutic agents targeting the nitric oxide/cyclic GMP signaling pathway have successfully treated patients with ED; however, the efficacies of these treatments are significantly lower in specific populations such as patients with diabetes. The goal of this study was to discover and identify new endothelium-derived relaxing factors involved in the regulation of erectile function, providing alternative therapeutic targets for treatment of ED. Immunoblotting results showed that protein expressions of epoxygenases from cytochrome P450 (CYP)2B, 2C and 2J subfamilies, as well as NADPH CYP reductase were present in rat corpora cavernosa, which was confirmed by immunohistochemical analysis. Furthermore, CYP2C was localized in cavernosal endothelial cells using double immunolabeling. CYP epoxygenase activity was analyzed by reverse-phase high-pressure liquid chromatography; and the results showed that 11,12- epoxyeicosatrienoic acid (EET) was the major product metabolized by CYP epoxygenases in rat corpora cavernosa. Inhibition of EETs function by injection of an EETs antagonist into rat penis significantly decreased intracavernosal pressure-induced by electrical stimulation of the major pelvic ganglion in vivo. In conclusion, our results suggest that EETs, produced by CYP epoxygenases, in penile endothelial cells serve as vasodilators. Inhibition of this pathway attenuated erectile function, suggesting that EETs are required for normal erection.
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Affiliation(s)
- Liming Jin
- Department of Physiology,Medical College of Georgia, Augusta, Georgia, USA.
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28
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Hashitani H, Yanai Y, Shirasawa N, Soji T, Tomita A, Kohri K, Suzuki H. Interaction between spontaneous and neurally mediated regulation of smooth muscle tone in the rabbit corpus cavernosum. J Physiol 2005; 569:723-35. [PMID: 16239265 PMCID: PMC1464276 DOI: 10.1113/jphysiol.2005.099309] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Interaction between spontaneous and neurally mediated regulation of tone in the corpus cavernosum smooth muscle (CCSM) of the rabbit was investigated. Changes in isometric muscle tension, intracellular Ca2+ concentration ([Ca2+]i) and membrane potential were recorded. CCSM developed spontaneous contractions, transient increases in [Ca2+]i (Ca2+ transients) and depolarizations. This spontaneous activity was abolished by blocking L-type Ca2+ channels (nicardipine, 1 mum), sarcoplasmic reticulum Ca2+ pump activity (cyclopiazonic acid, 10 microm), Ca2(+)-activated Cl- channels (niflumic acid, 10 mum) or cyclooxygenase-2 (COX-2; NS-398, 1 microm). Transmural nerve stimulation initiated either alpha-adrenergic contractions or nitrergic relaxations of CCSM depending on the level of muscle tone. NS-398 suppressed nerve-evoked contractions by about 70% but caused only a 40% reduction in the corresponding Ca2+ transient. Blocking nitric oxide synthase with N(omega)-nitro-l-arginine (LNA, 100 microm) reinforced nerve-evoked Ca2+ transients by about 150%, whilst increasing the corresponding Ca2+ transients by only 20%. In CCSM preparations that had been pre-contracted with either noradrenaline (0.3 microm) or prostaglandin F(2alpha) (0.1 microm), nerve stimulation inhibited about 70% of the contraction and caused only a 20% decrease in [Ca2+]i. Fluorescent immunohistochemistry with COX-2 antibodies and the reverse transcriptase-polymerase chain reaction (RT-PCR) method showed that the enzyme and its mRNA were highly expressed in the CCSM. These results suggest that spontaneously produced prostaglandins (PGs) not only contribute to the generation of spontaneous contractions but also facilitate nerve-evoked contractions. Conversely, spontaneously released nitric oxide (NO) suppresses excitation. Thus, interaction between spontaneous and neurally mediated regulation of CCSM tone may be fundamental to maintaining the muscle contractility. In addition, both PGs and NO appear to alter CCSM tone with only small changes in [Ca2+]i.
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Affiliation(s)
- Hikaru Hashitani
- Department of Regulatory Cell Physiology & Nephrourology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan.
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29
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Angulo J, Cuevas P, Gabancho S, Gonzalez-Corrochano R, Videla S, Saenz de Tejada I. ORIGINAL RESEARCH—BASIC SCIENCE: Enhancement of Both EDHF and NO/cGMP Pathways Is Necessary to Reverse Erectile Dysfunction in Diabetic Rats. J Sex Med 2005; 2:341-6. [PMID: 16422865 DOI: 10.1111/j.1743-6109.2005.20348.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS AND METHODS Phosphodiesterase 5 (PDE5) inhibitors are less effective in the treatment of erectile dysfunction (ED) in diabetic men than in nondiabetic patients. We have evaluated the effects of sildenafil, a PDE5 inhibitor that enhances the nitric oxide (NO)/cGMP pathway, calcium dobesilate (DOBE), which potentiates endothelium-derived hyperpolarizing factor (EDHF)-mediated responses and the combination of both on erectile responses elicited by cavernosal nerve electrical stimulation (CNES) in a rat model of ED after 8 weeks of streptozotocin-induced diabetes. RESULTS After 8 weeks of diabetes, erectile responses to CNES were significantly decreased in diabetic animals compared with nondiabetic time controls. While intravenous administration of sildenafil (0.3 mg/kg) or DOBE (10 mg/kg), individually, enhanced erectile responses in nondiabetic rats (214.7 +/- 34.1% and 268.5 +/- 30.1% of control response at 1 Hz, respectively), each failed to significantly enhance erectile responses in diabetic rats. Only when administered in combination did DOBE and sildenafil markedly potentiate erectile responses in these animals (380.1 +/- 88.6% of control response at 1 Hz), completely restoring erectile function. CONCLUSIONS These findings emphasize the importance of NO/cGMP and EDHF pathways for normal erectile function. They also give support to the in vitro observation that diabetes impairs NO and EDHF-dependent responses, precluding the complete recovery of erectile function with PDE5 inhibitors and explaining the relatively poor clinical response of diabetic men with ED to PDE5 inhibition. Finally, our study suggests that a pharmacological approach that combines enhancement of NO/cGMP and EDHF pathways could be necessary to treat ED in many diabetic men.
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Affiliation(s)
- Javier Angulo
- Instituto de Medicina Sexual, Fundación para la Investigación y el Desarollo en Andrología, Madrid, Spain.
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30
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Sáenz de Tejada I, Angulo J, Cellek S, González-Cadavid N, Heaton J, Pickard R, Simonsen U. Pathophysiology of Erectile Dysfunction. J Sex Med 2005; 2:26-39. [PMID: 16422902 DOI: 10.1111/j.1743-6109.2005.20103.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Multiple regulatory systems are involved in normal erectile function. Disruption of psychological, neurological, hormonal, vascular, and cavernosal factors, individually, or in combination, can induced erectile dysfunction (ED). The contribution of neurogenic, vascular, and cavernosal factors was thoroughly reviewed by our committee, while psychological and hormonal factors contributing to ED were evaluated by other committees. AIM To provide state of the art knowledge on the physiology of ED. METHODS An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees. Committee members established specific objectives and scopes for various male and female sexual medicine topics. The recommendations concerning state-of-the-art knowledge in the respective sexual medicine topic represent the opinion of experts from five different continents developed in a process over a 2-year period. Concerning the pathophysiology of ED committee, there were seven experts from five different countries. MAIN OUTCOME MEASURE Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate. RESULTS The epidemiology and classification of neurogenic ED was reviewed. The evidence for the association between vascular ED and atherosclerosis/hypercholesterolemia, hypertension and diabetes was evaluated. In addition, the pathophysiological mechanisms implicated in vascular ED were defined, including: arterial remodeling, increased vasoconstriction, impaired neurogenic vasodilatation, and impaired endothelium-dependent vasodilatation. The possible mechanisms underlying the association between chronic renal failure and ED were also evaluated as well as the evidence supporting the association of ED with various classes of medications. CONCLUSIONS A better understanding of how diseases interfere with the physiological mechanisms that regulate penile erection has been achieved over the last few years, which helps establish a strategy for the prevention and treatment of ED.
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31
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Behr-Roussel D, Gorny D, Mevel K, Compagnie S, Kern P, Sivan V, Bernabé J, Bedigian MP, Alexandre L, Giuliano F. Erectile dysfunction: an early marker for hypertension? A longitudinal study in spontaneously hypertensive rats. Am J Physiol Regul Integr Comp Physiol 2004; 288:R276-83. [PMID: 15297263 DOI: 10.1152/ajpregu.00040.2004] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Erectile dysfunction (ED) is another manifestation of vascular disease. We evaluated the natural history of ED in the spontaneously hypertensive rat (SHR) and the respective participation of associated pathophysiological modifications, i.e., endothelial dysfunction and tissue remodeling. SHR and their normotensive counterparts [Wistar-Kyoto rats (WKY)] of 6, 12, and 24 wk of age (n = 12) were used to evaluate erectile function, erectile and aortic tissue reactivity, and remodeling. Erectile responses in SHR are reduced at all ages (P < 0.001). In both aortic and erectile tissues of SHR and WKY, relaxations to ACh are altered progressively with age, although more markedly in SHR. They are decreased at 12 wk of age in erectile tissue of SHR compared with WKY (maximal relaxation: -19.2 +/- 2.8% vs. -28.3 +/- 3.9%, P < 0.001) but only at 24 wk of age in aortas (-47.9 +/- 6.4% vs. -90.5 +/- 2.9%, P < 0.001). Relaxations to sodium nitroprusside are unaltered in aortic rings of both strains but enhanced in erectile tissue of SHR at 12 wk of age. Major modifications in the distribution of collagen I, III, and V in SHR occur in both types of tissue and are detectable sooner in erectile tissue compared with aortic tissue. The onset of ED is detectable before the onset of hypertension in the SHR. Structural and functional alterations, while similar, occur earlier in erectile compared with vascular tissue. If confirmed in humans, ED could be an early warning sign for hypertension, and common therapeutic strategies targeting both ED and hypertension could be investigated.
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Affiliation(s)
- Delphine Behr-Roussel
- Pelvipharm, Domaine CNRS, 1 Avenue de la terrasse, BAtiment 5, 91190 Gif sur Yvette, France
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32
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Angulo J, Cuevas P, Fernández A, Gabancho S, Allona A, Martín-Morales A, Moncada I, Videla S, Sáenz de Tejada I. Diabetes impairs endothelium-dependent relaxation of human penile vascular tissues mediated by NO and EDHF. Biochem Biophys Res Commun 2003; 312:1202-8. [PMID: 14652001 DOI: 10.1016/j.bbrc.2003.11.034] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Standard treatments for erectile dysfunction (ED) (i.e., PDE5 inhibitors) are less effective in diabetic patients for unknown reasons. Endothelium-dependent relaxation (EDR) of human corpus cavernosum (HCC) depends on nitric oxide (NO), while in human penile resistance arteries (HPRA) endothelium-derived hyperpolarizing factor (EDHF) and NO participate. Here we show that diabetes significantly reduced EDR induced by acetylcholine (ACh) in HCC and HPRA. Relaxation attributed to EDHF was also impaired in HPRA from diabetic patients. The PDE5 inhibitor, sildenafil (10nM), reversed diabetes-induced endothelial dysfunction in HCC, but not in HPRA. Calcium dobesilate (DOBE; 10 microM) fully reversed diabetes-induced endothelial dysfunction in HPRA by specifically potentiating the EDHF-mediated component of EDR. Impairment by diabetes of NO and EDHF-dependent responses precluded the complete recovery of endothelial function in HPRA by sildenafil. This could explain the poor clinical response to PDE5 inhibitors of diabetic men with ED and suggests that a pharmacological approach that combines enhancement of NO/cGMP and EDHF pathways could be necessary to treat ED in many diabetic men.
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MESH Headings
- Acetylcholine/pharmacology
- Arteries/pathology
- Arteries/physiopathology
- Biological Factors/metabolism
- Calcium Dobesilate/pharmacology
- Diabetes Complications
- Diabetes Mellitus/pathology
- Diabetes Mellitus/physiopathology
- Dose-Response Relationship, Drug
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Erectile Dysfunction/etiology
- Erectile Dysfunction/pathology
- Erectile Dysfunction/physiopathology
- Humans
- Impotence, Vasculogenic/etiology
- Impotence, Vasculogenic/pathology
- Impotence, Vasculogenic/physiopathology
- Male
- Middle Aged
- Muscle Contraction/drug effects
- Muscle Relaxation/drug effects
- Muscle, Smooth, Vascular/blood supply
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- Nitric Oxide/metabolism
- Penis/blood supply
- Penis/drug effects
- Penis/pathology
- Penis/physiopathology
- Piperazines
- Purines
- Reference Values
- Sildenafil Citrate
- Stress, Mechanical
- Sulfones
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Affiliation(s)
- Javier Angulo
- Fundación para la Investigación y el Desarrollo en Andrología. 28304, Madrid, Spain.
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