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Condina A, Lykina T. Treatment Outcomes of Diabetic Patients With Erectile Dysfunction Prescribed High-Dose Tadalafil. Cureus 2023; 15:e34812. [PMID: 36915849 PMCID: PMC10008086 DOI: 10.7759/cureus.34812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2023] [Indexed: 02/11/2023] Open
Abstract
Objective: To assess the treatment outcome of diabetic patients with erectile dysfunction who are prescribed an alternate daily high dose of tadalafil over a 120-day treatment period. Methods: This was a single-site, retrospective, observational study of 63 diabetic men with erectile dysfunction prescribed an alternate daily dose of 30mg of tadalafil between January 1, 2021, and December 31, 2021. Treatment outcomes accessed medication compliance, adverse drug reactions, and patient treatment satisfaction at 60- and 120-days treatment. Results: Mean age of patients was 58.3 years and included patients who suffered from comorbidities ranging from hypertension (54.0%), dyslipidemia (52.3%), and depression (9.5%). At 60 days in the study, 69.8% were satisfied and continued the treatment. However, at the end of the 120-treatment period, a low number of men (17.5%) were satisfied with the treatment and therefore did not remain on the treatment protocol. These patients reported a lack of medication dose efficacy (86.5%), non-compliance with treatment as prescribed (65.4%), and adverse drug reactions (30.8%) as reasons for discontinuing treatment. None of the identified patient demographics were significantly associated with 120-day continuous treatment. Similarly, the odds ratio derived from the logistic regression did not demonstrate an association between the selected variables and the outcome of 120-day continuous treatment retention. Conclusion: This retrospective case series study found that 82.5% of diabetic patients were not satisfied with treatment with alternate dosing of 30mg tadalafil to treat their ED at the end of the 120-day treatment period suggesting an alternative treatment plan.
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Affiliation(s)
| | - Tatiana Lykina
- Allergy and Immunology, Oceania University of Medicine, Samoa, AUS
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2
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Yıldırım Ç, Salman MY, Yavuz A, Bayar G. Comparison of three different tadalafil regimens for erectile dysfunction treatment in patients with diabetes mellitus microvascular complications. Andrologia 2022; 54:e14536. [DOI: 10.1111/and.14536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 06/22/2022] [Accepted: 06/29/2022] [Indexed: 11/29/2022] Open
Affiliation(s)
| | - Mehmet Yılmaz Salman
- Urology Department Sancaktepe Martyr Prof Dr Ilhan Varank Training and Research Hospital Istanbul Turkey
| | | | - Göksel Bayar
- Urology Department Gelisim Private Hospital İskenderun Turkey
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3
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Comerma-Steffensen S, Prat-Duran J, Mogensen S, Fais R, Pinilla E, Simonsen U. Erectile Dysfunction and Altered Contribution of KCa1.1 and KCa2.3 Channels in the Penile Tissue of Type-2 Diabetic db/db Mice. J Sex Med 2022; 19:697-710. [PMID: 37057569 DOI: 10.1016/j.jsxm.2022.02.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/15/2022] [Accepted: 02/19/2022] [Indexed: 11/17/2022]
Abstract
BACKGROUND Activation of endothelial small conductance calcium-activated K+ channels (KCa2.3) and intermediate conductance calcium-activated K+ channels (KCa3.1) leads to vascular relaxation. We found endothelial KCa2.3 down-regulation in the corpus cavernosum diminishes erectile function. AIM We hypothesized that in type-2 diabetic mice, the function of KCa2.3 and KCa1.1 channels is impaired in erectile tissue. METHODS Erectile function was measured, and corpus cavernosum strips were mounted for functional studies and processed for qPCR and immunoblotting. OUTCOMES Effects of type 2 diabetes on erectile function, expression and function of calcium-activated potassium channels. RESULTS In anesthetized diabetic db/db mice, erectile function was markedly decreased compared to non-diabetic heterozygous db/+ mice, and the impairment was even more pronounced compared to normal C57BL/6 mice. qPCR revealed KCa2.3 and KCa1.1α channel expressions were upregulated in corpus cavernosum from db/db mice. Immunoblotting showed down-regulation of KCa2.3 channels in the corpus cavernosum from db/db mice. Acetylcholine relaxations were impaired while relaxations induced by the nitric oxide, donor SNP were unaltered in corpus cavernosum from db/db compared to C57BL/6 and db/+ mice. Apamin, a blocker of KCa2 channels, inhibited acetylcholine relaxation in corpus cavernosum from all experimental groups. In the presence of apamin, acetylcholine relaxation was markedly decreased in corpus cavernosum from db/db vs C57BL/6 and db/+ mice. An opener of KCa2 and KCa3.1 channels, NS309, potentiated acetylcholine relaxations in corpus cavernosum from db/+ and db/db mice. Iberiotoxin, a blocker of KCa1.1 channels, inhibited acetylcholine relaxation in corpus cavernosum from db/+ mice, while there was no effect in tissue from db/db mice. CLINICAL TRANSLATION Erectile function in diabetic db/db mice was severely affected compared to heterozygous and control mice, findings suggesting the non-diabetic db/+ and diabetic db/db mice for translational purpose can be used for drug testing on, respectively, moderate and severe erectile dysfunction. The altered expressions and impaired acetylcholine relaxation in the presence of apamin compared to C57BL/6 mice may suggest decreased KCa1.1 channel function may underpin impaired endothelium-dependent relaxation and erectile dysfunction in diabetic db/db mice. STRENGTHS & LIMITATIONS The present study provides a mouse model for type 2 diabetes to test moderate and severe erectile dysfunction drugs. Decreased KCa1.1 channel function contributes to erectile dysfunction, and it is a limitation that it is not supported by electrophysiological measurements. CONCLUSION Our results suggest that the contribution of iberiotoxin-sensitive KCa1.1 channels to relaxation is reduced in the corpus cavernosum, while apamin-sensitive KCa2.3 channels appear upregulated. The impaired KCa1.1 channel function may contribute to the impaired erectile function in diabetic db/db mice.
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Affiliation(s)
- Simon Comerma-Steffensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Department of Biomedical Sciences/Animal Physiology, Veterinary Faculty, Central University of Venezuela, Maracay, Aragua, Venezuela
| | | | - Susie Mogensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Rafael Fais
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Pharmacology Department, Ribeirao Preto Medical School, Sao Paulo University, Brasil
| | | | - Ulf Simonsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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4
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Cirino G, Szabo C, Papapetropoulos A. Physiological roles of hydrogen sulfide in mammalian cells, tissues and organs. Physiol Rev 2022; 103:31-276. [DOI: 10.1152/physrev.00028.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
H2S belongs to the class of molecules known as gasotransmitters, which also includes nitric oxide (NO) and carbon monoxide (CO). Three enzymes are recognized as endogenous sources of H2S in various cells and tissues: cystathionine g-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). The current article reviews the regulation of these enzymes as well as the pathways of their enzymatic and non-enzymatic degradation and elimination. The multiple interactions of H2S with other labile endogenous molecules (e.g. NO) and reactive oxygen species are also outlined. The various biological targets and signaling pathways are discussed, with special reference to H2S and oxidative posttranscriptional modification of proteins, the effect of H2S on channels and intracellular second messenger pathways, the regulation of gene transcription and translation and the regulation of cellular bioenergetics and metabolism. The pharmacological and molecular tools currently available to study H2S physiology are also reviewed, including their utility and limitations. In subsequent sections, the role of H2S in the regulation of various physiological and cellular functions is reviewed. The physiological role of H2S in various cell types and organ systems are overviewed. Finally, the role of H2S in the regulation of various organ functions is discussed as well as the characteristic bell-shaped biphasic effects of H2S. In addition, key pathophysiological aspects, debated areas, and future research and translational areas are identified A wide array of significant roles of H2S in the physiological regulation of all organ functions emerges from this review.
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Affiliation(s)
- Giuseppe Cirino
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Naples, Italy
| | - Csaba Szabo
- Chair of Pharmacology, Section of Medicine, University of Fribourg, Switzerland
| | - Andreas Papapetropoulos
- Laboratory of Pharmacology, Faculty of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece & Clinical, Experimental Surgery and Translational Research Center, Biomedical Research Foundation of the Academy of Athens, Greece
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5
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Chawla R, Madhu SV, Makkar BM, Ghosh S, Saboo B, Kalra S. RSSDI-ESI Clinical Practice Recommendations for the Management
of Type 2 Diabetes Mellitus 2020. Int J Diabetes Dev Ctries 2020. [PMCID: PMC7371966 DOI: 10.1007/s13410-020-00819-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Rajeev Chawla
- North Delhi Diabetes Centre Rohini, New Delhi, India
| | - S. V. Madhu
- Centre for Diabetes, Endocrinology & Metabolism, UCMS-GTB Hospital, Delhi, India
| | - B. M. Makkar
- Dr Makkar’s Diabetes & Obesity Centre Paschim Vihar, New Delhi, India
| | - Sujoy Ghosh
- Department of Endocrinology & Metabolism, Institute of Post Graduate Medical Education & Research, Kolkata, West Bengal India
| | - Banshi Saboo
- DiaCare - A Complete Diabetes Care Centre, Ahmedabad, India
| | - Sanjay Kalra
- Department of Endocrinology, Bharti Hospital, Karnal, Haryana India
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6
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Chawla R, Madhu SV, Makkar BM, Ghosh S, Saboo B, Kalra S. RSSDI-ESI Clinical Practice Recommendations for the Management of Type 2 Diabetes Mellitus 2020. Indian J Endocrinol Metab 2020; 24:1-122. [PMID: 32699774 PMCID: PMC7328526 DOI: 10.4103/ijem.ijem_225_20] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Rajeev Chawla
- North Delhi Diabetes Centre, Rohini, New Delhi, India
| | - S. V. Madhu
- Centre for Diabetes, Endocrinology and Metabolism, UCMS-GTB Hospital, New Delhi, India
| | - B. M. Makkar
- Dr. Makkar's Diabetes and Obesity Centre, Paschim Vihar, New Delhi, India
| | - Sujoy Ghosh
- Department of Endocrinology and Metabolism, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India
| | - Banshi Saboo
- DiaCare - A Complete Diabetes Care Centre, Ahmedabad, Gujarat, India
| | - Sanjay Kalra
- Department of Endocrinology, Bharti Hospital, Karnal, Haryana, India
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7
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Endothelium-Dependent Hyperpolarization (EDH) in Diabetes: Mechanistic Insights and Therapeutic Implications. Int J Mol Sci 2019; 20:ijms20153737. [PMID: 31370156 PMCID: PMC6695796 DOI: 10.3390/ijms20153737] [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: 07/03/2019] [Revised: 07/25/2019] [Accepted: 07/30/2019] [Indexed: 02/07/2023] Open
Abstract
Diabetes mellitus is one of the major risk factors for cardiovascular disease and is an important health issue worldwide. Long-term diabetes causes endothelial dysfunction, which in turn leads to diabetic vascular complications. Endothelium-derived nitric oxide is a major vasodilator in large-size vessels, and the hyperpolarization of vascular smooth muscle cells mediated by the endothelium plays a central role in agonist-mediated and flow-mediated vasodilation in resistance-size vessels. Although the mechanisms underlying diabetic vascular complications are multifactorial and complex, impairment of endothelium-dependent hyperpolarization (EDH) of vascular smooth muscle cells would contribute at least partly to the initiation and progression of microvascular complications of diabetes. In this review, we present the current knowledge about the pathophysiology and underlying mechanisms of impaired EDH in diabetes in animals and humans. We also discuss potential therapeutic approaches aimed at the prevention and restoration of EDH in diabetes.
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8
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Liu J, Li S, Sun D. Calcium Dobesilate and Micro-vascular diseases. Life Sci 2019; 221:348-353. [PMID: 30769115 DOI: 10.1016/j.lfs.2019.02.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/02/2019] [Accepted: 02/10/2019] [Indexed: 12/26/2022]
Abstract
Micro-vascular diseases and its associated complications continue to be a significant health problem worldwide. Vascular lesions from microvascular involvement lead to impaired blood flow and contribute to damage and dysfunction of one or more target organs, that is, the heart, kidneys, eyes, and nervous system. Calcium Dobesilate Drug (CAD) is an established vasoactive and angioprotective drug that has shown a unique, multitarget mode of action in several experimental studies and in different animal models of diabetic microvascular complications. CAD has been widely used as an antioxidant and a vascular protective agent. At present, the application of Calcium Dobesilate is mainly related to Micro-vascular damage-related diseases, such as diabetic retinopathy (DR) and diabetic nephropathy (DN), and it is found to significantly improve the related symptoms. Its beneficial effects make it an attractive therapeutic compound especially in the early stages of these diseases. Scholars at home and abroad have studied the effectiveness, safety, and mechanisms of the related diseases, furthermore, the subjects involved patients and animal models, they have found some new clinical effects of this medicine. This paper makes a brief summary of a research progress of clinical application about Vascular injury related diseases and other aspects.
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Affiliation(s)
- Jie Liu
- Department of Nephrology, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, China; Department of Nephrology, Second Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, China
| | - Shulin Li
- Department of Nephrology, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, China
| | - Dong Sun
- Department of Nephrology, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, China; Department of Internal Medicine and Diagnostics, Xuzhou Medical University, Xuzhou 221002, China.
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9
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Zhao H, Jiang J, Xia J, Jiang R. Effect of low androgen levels on IKca and SKca3 channels in rat penile corpus cavernosum. Andrologia 2018; 50:e13075. [PMID: 29952429 DOI: 10.1111/and.13075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 04/27/2018] [Accepted: 05/09/2018] [Indexed: 12/12/2022] Open
Affiliation(s)
- Hu Zhao
- Department of Urology; Affiliated Hospital; Southwest Medical University; Luzhou China
| | - Jun Jiang
- Department of thyroid Surgery; Affiliated Hospital; Southwest Medical University; Luzhou China
| | - Jiyi Xia
- Medical research center; Affiliated Hospital; Southwest Medical University; Luzhou China
| | - Rui Jiang
- Department of Urology; Affiliated Hospital; Southwest Medical University; Luzhou China
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10
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Ng HH, Leo CH, Parry LJ, Ritchie RH. Relaxin as a Therapeutic Target for the Cardiovascular Complications of Diabetes. Front Pharmacol 2018; 9:501. [PMID: 29867503 PMCID: PMC5962677 DOI: 10.3389/fphar.2018.00501] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/26/2018] [Indexed: 12/13/2022] Open
Abstract
Cardiovascular complications are the major cause of mortality in patients with diabetes. This is closely associated with both macrovascular and microvascular complications of diabetes, which lead to organ injuries in diabetic patients. Previous studies have consistently demonstrated the beneficial effects of relaxin treatment for protection of the vasculature, with evidence of antioxidant and anti-remodeling actions. Relaxin enhances nitric oxide, prostacyclin and endothelium-derived hyperpolarization (EDH)-type-mediated relaxation in various vascular beds. These effects of relaxin on the systemic vasculature, coupled with its cardiac actions, reduce pulmonary capillary wedge pressure and pulmonary artery pressure. This results in an overall decrease in systemic and pulmonary vascular resistance in heart failure patients. The anti-fibrotic actions of relaxin are well established, a desirable property in the context of diabetes. Further, relaxin ameliorates diabetic wound healing, with accelerated angiogenesis and vasculogenesis. Relaxin-mediated stimulation of vascular endothelial growth factor (VEGF) and stromal cell-derived factor 1-α, as well as regulation of metalloproteinase expression, ameliorates cardiovascular fibrosis in diabetic mice. In the heart, relaxin is a cardioprotective molecule in several experimental animal models, exerting anti-fibrotic, anti-hypertrophy and anti-apoptotic effects in diabetic pathologies. Collectively, these studies provide a foundation to propose the therapeutic potential for relaxin as an adjunctive agent in the prevention or treatment of diabetes-induced cardiovascular complications. This review provides a comprehensive overview of the beneficial effects of relaxin, and identifies its therapeutic possibilities for alleviating diabetes-related cardiovascular injury.
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Affiliation(s)
- Hooi Hooi Ng
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
- Heart Failure Pharmacology, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Chen Huei Leo
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
- Science and Math Cluster, Singapore University of Technology and Design, Singapore, Singapore
| | - Laura J. Parry
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Rebecca H. Ritchie
- Heart Failure Pharmacology, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Pharmacology & Therapeutics, The University of Melbourne, Melbourne, VIC, Australia
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11
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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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12
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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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13
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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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14
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Dal S, Sigrist S. The Protective Effect of Antioxidants Consumption on Diabetes and Vascular Complications. Diseases 2016; 4:E24. [PMID: 28933404 PMCID: PMC5456287 DOI: 10.3390/diseases4030024] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/20/2016] [Accepted: 06/23/2016] [Indexed: 12/14/2022] Open
Abstract
Obesity and diabetes is generally accompanied by a chronic state of oxidative stress, disequilibrium in the redox balance, implicated in the development and progression of complications such as micro- and macro-angiopathies. Disorders in the inner layer of blood vessels, the endothelium, play an early and critical role in the development of these complications. Blunted endothelium-dependent relaxation and/or contractions are quietly associated to oxidative stress. Thus, preserving endothelial function and oxidative stress seems to be an optimization strategy in the prevention of vascular complications associated with diabetes. Diet is a major lifestyle factor that can greatly influence the incidence and the progression of type 2 diabetes and cardiovascular complications. The notion that foods not only provide basic nutrition but can also prevent diseases and ensure good health and longevity is now attained greater prominence. Some dietary and lifestyle modifications associated to antioxidative supply could be an effective prophylactic means to fight against oxidative stress in diabesity and complications. A significant benefit of phytochemicals (polyphenols in wine, grape, teas), vitamins (ascorbate, tocopherol), minerals (selenium, magnesium), and fruits and vegetables in foods is thought to be capable of scavenging free radicals, lowering the incidence of chronic diseases. In this review, we discuss the role of oxidative stress in diabetes and complications, highlight the endothelial dysfunction, and examine the impact of antioxidant foods, plants, fruits, and vegetables, currently used medication with antioxidant properties, in relation to the development and progression of diabetes and cardiovascular complications.
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Affiliation(s)
- Stéphanie Dal
- DIATHEC EA 7294 UMR Centre Européen d'Etude du Diabète (CeeD), Université de Strasbourg (UdS), boulevard René Leriche, Strasbourg 67200, France.
| | - Séverine Sigrist
- DIATHEC EA 7294 UMR Centre Européen d'Etude du Diabète (CeeD), Université de Strasbourg (UdS), boulevard René Leriche, Strasbourg 67200, France.
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Assar ME, Angulo J, Rodríguez-Mañas L. Diabetes and ageing-induced vascular inflammation. J Physiol 2015; 594:2125-46. [PMID: 26435167 DOI: 10.1113/jp270841] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/28/2015] [Indexed: 12/16/2022] Open
Abstract
Diabetes and the ageing process independently increase the risk for cardiovascular disease (CVD). Since incidence of diabetes increases as people get older, the diabetic older adults represent the largest population of diabetic subjects. This group of patients would potentially be threatened by the development of CVD related to both ageing and diabetes. The relationship between CVD, ageing and diabetes is explained by the negative impact of these conditions on vascular function. Functional and clinical evidence supports the role of vascular inflammation induced by the ageing process and by diabetes in vascular impairment and CVD. Inflammatory mechanisms in both aged and diabetic vasculature include pro-inflammatory cytokines, vascular hyperactivation of nuclear factor-кB, increased expression of cyclooxygenase and inducible nitric oxide synthase, imbalanced expression of pro/anti-inflammatory microRNAs, and dysfunctional stress-response systems (sirtuins, Nrf2). In contrast, there are scarce data regarding the interaction of these mechanisms when ageing and diabetes co-exist and its impact on vascular function. Older diabetic animals and humans display higher vascular impairment and CVD risk than those either aged or diabetic, suggesting that chronic low-grade inflammation in ageing creates a vascular environment favouring the mechanisms of vascular damage driven by diabetes. Further research is needed to determine the specific inflammatory mechanisms responsible for exacerbated vascular impairment in older diabetic subjects in order to design effective therapeutic interventions to minimize the impact of vascular inflammation. This would help to prevent or delay CVD and the specific clinical manifestations (cognitive decline, frailty and disability) promoted by diabetes-induced vascular impairment in the elderly.
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Affiliation(s)
- Mariam El Assar
- Instituto de Investigación Sanitaria del 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
- Instituto de Investigación Sanitaria del Hospital Universitario de Getafe, Getafe, Spain.,Servicio de Geriatría, Hospital Universitario de Getafe, Getafe, Spain
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Impaired endothelial calcium signaling is responsible for the defective dilation of mesenteric resistance arteries from db/db mice to acetylcholine. Eur J Pharmacol 2015; 767:17-23. [DOI: 10.1016/j.ejphar.2015.09.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/24/2015] [Accepted: 09/24/2015] [Indexed: 11/22/2022]
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Kutlu O, Karaguzel E, Gurgen SG, Okatan AE, Kutlu S, Bayraktar C, Kazaz IO, Eren H. Antifibrogenic role of valproic acid in streptozotocin induced diabetic rat penis. Andrologia 2015; 48:453-63. [DOI: 10.1111/and.12465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2015] [Indexed: 01/10/2023] Open
Affiliation(s)
- O. Kutlu
- Department of Urology; School of Medicine; Karadeniz Technical University; Trabzon Turkey
| | - E. Karaguzel
- Department of Urology; School of Medicine; Karadeniz Technical University; Trabzon Turkey
| | - S. G. Gurgen
- School of Vocational Health Service; Celal Bayar University; Manisa Turkey
| | - A. E. Okatan
- Department of Urology; School of Medicine; Karadeniz Technical University; Trabzon Turkey
| | - S. Kutlu
- Department of Urology; Aydin State Hospital; Aydin Turkey
| | - C. Bayraktar
- Department of Urology; School of Medicine; Karadeniz Technical University; Trabzon Turkey
| | - I. O. Kazaz
- Department of Urology; School of Medicine; Karadeniz Technical University; Trabzon Turkey
| | - H. Eren
- Department of Urology; School of Medicine; Karadeniz Technical University; Trabzon Turkey
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Wong PS, Randall MD, Roberts RE. Sex differences in the role of NADPH oxidases in endothelium-dependent vasorelaxation in porcine isolated coronary arteries. Vascul Pharmacol 2015; 72:83-92. [PMID: 25872163 DOI: 10.1016/j.vph.2015.04.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 03/30/2015] [Accepted: 04/04/2015] [Indexed: 11/18/2022]
Abstract
The present study examined whether vascular function, expression and activity of NADPH oxidases differ between sexes in porcine isolated coronary arteries (PCAs) using selective Nox inhibitors, ML-171 and VAS2870. Vascular responses of distal PCAs were examined under myographic conditions in the presence of a range of inhibitors. Nox activity in PCA homogenates was assessed using lucigenin-enhanced chemiluminescence. Protein expression of Nox1, Nox2 and Nox4 was compared using Western immunoblotting. The presence of ML-171 or DPI had no effect on the bradykinin-induced vasorelaxation in PCAs from females. In males, DPI shifted the EC50 2.8-fold to the right. In the presence of L-NAME and indomethacin, DPI and ML-171 had no effect in females, but enhanced the bradykinin-induced vasorelaxation in males. ML-171 had no effect on the forskolin-induced vasorelaxation but decreased the potency of U46619-induced tone in both sexes in the absence or presence of endothelium. VAS2870 had no effect on the bradykinin-induced vasorelaxation in both sexes but reduces the EDH-type response in males only. Nox activity was reduced by DPI and ML-171, but not VAS2870 in PCAs from both sexes. Protein expression of Nox1 and Nox2 in PCAs was higher in males compared to females whereas Nox4 was higher in females. Inhibition of Nox with ML-171 enhances while VAS2870 reduces the EDH-type response in PCAs from males but not females. This indicates that Nox-generated ROS play a role in the EDH-type response in males with differences attributed to the differential expression of Nox isoforms. This may underlie the greater oxidative stress observed in males.
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Affiliation(s)
- Pui San Wong
- Pharmacology Research Group, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom
| | - Michael D Randall
- Pharmacology Research Group, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom.
| | - Richard E Roberts
- Pharmacology Research Group, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom
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Abstract
In this chapter the role played by H2S in the physiopathology of urogenital tract revising animal and human data available in the current relevant literature is discussed. H2S pathway has been demonstrated to be involved in the mechanism underlying penile erection in human and experimental animal. Both cystathionine-β synthase (CBS) and cystathionine-γ lyase (CSE) are expressed in the human corpus cavernosum and exogenous H2S relaxes isolated human corpus cavernosum strips in an endothelium-independent manner. Hydrogen sulfide pathway also accounts for the direct vasodilatory effect operated by testosterone on isolated vessels. Convincing evidence suggests that H2S can influence the cGMP pathway by inhibiting the phosphodiesterase 5 (PDE-5) activity. All these findings taken together suggest an important role for the H2S pathway in human corpus cavernosum homeostasis. However, H2S effect is not confined to human corpus cavernosum but also plays an important role in human bladder. Human bladder expresses mainly CBS and generates in vitro detectable amount of H2S. In addition the bladder relaxant effect of the PDE-5 inhibitor sildenafil involves H2S as mediator. In conclusion the H2S pathway is not only involved in penile erection but also plays a role in bladder homeostasis. In addition the finding that it involved in the mechanism of action of PDE-5 inhibitors strongly suggests that modulation of this pathway can represent a therapeutic target for the treatment of erectile dysfunction and bladder diseases.
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Schach C, Resch M, Schmid PM, Riegger GA, Endemann DH. Type 2 diabetes: increased expression and contribution of IKCa channels to vasodilation in small mesenteric arteries of ZDF rats. Am J Physiol Heart Circ Physiol 2014; 307:H1093-102. [DOI: 10.1152/ajpheart.00240.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Impaired endothelial function, which is dysregulated in diabetes, also precedes hypertension. We hypothesized that in Type 2 diabetes, the impaired endothelium-dependent relaxation is due to a loss of endothelium-derived hyperpolarization (EDH) that is regulated by impaired ion channel function. Zucker diabetic fatty (ZDF), Zucker heterozygote, and homozygote lean control rats were used as the experimental models in our study. Third-order mesenteric arteries were dissected and mounted on a pressure myograph; mRNA was quantified by RT-PCR and channel proteins by Western blotting. Under nitric oxide (NO) synthase and cyclooxygenase inhibition, endothelial stimulation with ACh fully relaxes control but not diabetic arteries. In contrast, when small-conductance calcium-activated potassium (KCa) channels and intermediate- and large-conductance KCa (I/BKCa) are inhibited with apamin and charybdotoxin, NO is able to compensate for ACh-induced relaxation in control but not in diabetic vessels. After replacement of charybdotoxin with 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34; IKCa inhibitor), ACh-induced relaxation in diabetic animals is attenuated. Specific inhibition with TRAM-34 or charybdotoxin attenuates ACh relaxation in diabetes. Stimulation with 1-ethyl-2-benzimidazolinone (IKCa activator) shows a reduced relaxation in diabetes. Activation of BKCa with 1,3-dihydro-1-[2-hydroxy-5-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-2H-benzimidazol-2-one NS619 leads to similar relaxations of control and diabetic arteries. RT-PCR and Western blot analysis demonstrate elevated mRNA and protein expression levels of IKCa in diabetes. Our results suggest that the compensatory effect of NO and EDH-associated, endothelium-dependent relaxation is reduced in ZDF rats. Specific blockade of IKCa with TRAM-34 reduces NO and EDH-type relaxation in diabetic rats, indicating an elevated contribution of IKCa in diabetic small mesenteric artery relaxation. This finding correlates with increased IKCa mRNA and protein expression in this vessel.
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Affiliation(s)
- Christian Schach
- Department of Cardiology, University Hospital Regensburg, Regensburg, Germany
| | - Markus Resch
- Department of Cardiology, University Hospital Regensburg, Regensburg, Germany
| | - Peter M. Schmid
- Department of Cardiology, University Hospital Regensburg, Regensburg, Germany
| | - Guenter A. Riegger
- Department of Cardiology, University Hospital Regensburg, Regensburg, Germany
| | - Dierk H. Endemann
- Department of Cardiology, University Hospital Regensburg, Regensburg, Germany
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Possibility of inhibition of calcium-activated chloride channel rescuing erectile failures in diabetes. Int J Impot Res 2014; 26:151-5. [PMID: 24522228 DOI: 10.1038/ijir.2014.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 10/07/2013] [Accepted: 12/20/2013] [Indexed: 02/06/2023]
Abstract
Although calcium-activated chloride channel (CaCC) blockers, niflumic acid (NFA) and anthracene-9-carboxylic acid (A9C), have been shown as potential erectogenic agents in healthy corpus cavernosum (CC) tissues, the pharmacological characteristics of CaCC blockers in diabetic state are relatively unknown. This study compares the direct muscle relaxant property of NFA and A9C with their influence on contraction and nitrergic relaxation as elicited by electrical field stimulation in normal and 16-week-old diabetic rabbit CC (n=8). Mean blood glucose level in alloxan-treated rabbits was elevated threefold (21.9±0.5 mmol l(-1) vs 7.1±0.2 mmol l(-1) in untreated rabbits; P<0.05). There was no significant alteration in the efficacies of NFA and A9C in eliciting a concentration-dependent relaxation of noradrenaline-induced cavernosum tone and in inhibiting neurogenic contraction of CC from diabetic rabbits. The capability of NFA (100 μM) and A9C (1 mM) in augmenting nitrergic transmission was also not adversely affected by diabetes. However, in CC from diabetic rabbits, A9C markedly increased nitrergic relaxation response to 1-10 Hz by 10.6-36.6% (vs -5.1-0.8% in nondiabetic control). CaCC sensitivity to A9C appears to be enhanced in diabetic CC tissue. Inhibiting the CaCC activity in diabetes-related ED may tip the balance between proerectile/relaxant and antierectile/contractile mechanisms in favor of cavernosum relaxation.
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Zheng H, Liu X, Patel KP. Centrally mediated erectile dysfunction in rats with type 1 diabetes: role of angiotensin II and superoxide. J Sex Med 2013; 10:2165-76. [PMID: 23841890 DOI: 10.1111/jsm.12248] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Erectile dysfunction is a serious complication of diabetes mellitus. Apart from the peripheral actions, central mechanisms are also responsible for penile erection. AIM This study aims to determine the contribution of angiotensin (ANG) II in the dysfunction of central N-methyl-D-aspartic acid (NMDA)- and nitric oxide (NO)-induced erectile responses in streptozotocin-induced type 1 diabetic (T1D) rats. METHODS Three weeks after streptozotocin injections, rats were randomly treated with the angiotensin-converting enzyme inhibitor-enalapril, or the ANG II type 1 receptor blocker, losartan, or the superoxide dismutase mimetic, tempol, or vehicle via chronic intracerebroventricular infusion by osmotic mini-pump for 2 weeks. MAIN OUTCOME MEASURE Central NMDA receptor stimulation or the administration of the NO donor, sodium nitroprusside (SNP)-induced penile erectile responses and concurrent behavioral responses were monitored in conscious rats. RESULTS Two weeks of enalapril, losartan, or tempol treatment significantly improved the erectile responses to central microinjection of both NMDA and SNP in the paraventricular nucleus (PVN) of conscious T1D rats (NMDA responses-T1D+enalapril: 1.7 ± 0.6, T1D+losartan: 2.0 ± 0.3, T1D+tempol: 2.0 ± 0.6 vs. T1D+vehicle: 0.6 ± 0.3 penile erections/rat in the first 20 minutes, P < 0.05; SNP responses-T1D+enalapril: 0.9 ± 0.3, T1D+losartan: 1.3 ± 0.3, T1D+tempol: 1.4 ± 0.4 vs. T1D+vehicle: 0.4 ± 0.2 penile erections/rat in the first 20 minutes, P < 0.05). Concurrent behavioral responses including yawning and stretching, induced by central NMDA and SNP microinjections, were also significantly increased in T1D rats after enalapril, losartan, or tempol treatments. Neuronal NO synthase expression within the PVN was also significantly increased, and superoxide production was reduced in T1D rats after these treatments. CONCLUSIONS These data strongly support the contention that enhanced ANG II mechanism/s within the PVN of T1D rats contributes to the dysfunction of central NMDA-induced erectile responses in T1D rats via stimulation of superoxide.
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Affiliation(s)
- Hong Zheng
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, USA
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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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Hydrogen sulfide promotes nitric oxide production in corpus cavernosum by enhancing expression of endothelial nitric oxide synthase. Int J Impot Res 2012; 25:86-90. [PMID: 23171981 DOI: 10.1038/ijir.2012.39] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recently, hydrogen sulfide (H2S) has been identified as a potential therapy for ED. However, a thorough understanding of its molecular mechanisms of action would be essential to develop H2S as a new therapy for ED. In this study, the effect of H2S on nitric oxide (NO) production, especially through the expression of constitutive nitric oxide synthase (NOS) isoforms-endothelial NOS (eNOS) and neuronal NOS (nNOS) in rat corpus cavernosum (CC) were explored. Real-time PCR studies subsequent to in vitro treatment of sodium hydrosulfide hydrate (NaHS), a stable H2S donor, showed increases in eNOS but not nNOS mRNA. Western blot studies confirmed that the exogenously applied NaHS increased eNOS but not nNOS protein expression in the rat CC. Furthermore, NaHS did not alter the expressed amounts of Caveolin-1 (CAV-1), a dominant inhibitory interaction partner of eNOS, in these tissues. Not surprisingly, NaHS also enhanced the NO production in eNOS-associated membrane fraction of rat CC. Taken together, we ascertain that H2S could exert its proerectile effects by augmenting NO pathway. It appears that H2S would be particularly useful in improving the clinical outcome of ED patients, whose erectile impairment is due to an inherent attenuation of the endothelial NO formation in the cavernosum.
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Schjørring O, Kun A, Flyvbjerg A, Kirkeby HJ, Jensen JB, Simonsen U. Flow‐Evoked Vasodilation Is Blunted in Penile Arteries from Zucker Diabetic Fatty Rats. J Sex Med 2012; 9:1789-800. [DOI: 10.1111/j.1743-6109.2012.02743.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Tsai SH, Hein TW, Kuo L, Yang VC. High glucose impairs EDHF-mediated dilation of coronary arterioles via reduced cytochrome P450 activity. Microvasc Res 2011; 82:356-63. [DOI: 10.1016/j.mvr.2011.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 08/31/2011] [Accepted: 09/23/2011] [Indexed: 11/26/2022]
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Félétou M. The Endothelium, Part I: Multiple Functions of the Endothelial Cells -- Focus on Endothelium-Derived Vasoactive Mediators. ACTA ACUST UNITED AC 2011. [DOI: 10.4199/c00031ed1v01y201105isp019] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Suresh S, Prakash S. Effect of Mucuna pruriens (Linn.) on oxidative stress-induced structural alteration of corpus cavernosum in streptozotocin-induced diabetic rat. J Sex Med 2011; 8:1943-56. [PMID: 21366877 DOI: 10.1111/j.1743-6109.2011.02221.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Erectile dysfunction is one of the major secondary complications of diabetes. Mucuna pruriens (M. pruriens), a leguminous plant identified for its antidiabetic, aphrodisiac, and fertility enhancing properties, has been the choice of Indian traditional medicine. AIM The objective of the present study was to analyze the efficacy of M. pruriens on free radicals-mediated penile tissue alterations in hyperglycemic male rats. Methods. Male albino rats were divided as group I (sham) control, group II (STZ) diabetes-induced (streptozotocin 60 mg/kg of body weight [bw] in 0.1 M citrate buffer), group III (STZ + MP) diabetic rats administered with 200 mg/kg bw of ethanolic extract of M. pruriens seed, group IV (STZ + SIL) diabetic rats administered with 5 mg/kg bw of sildenafil citrate, group V (sham + MP) administered with 200 mg/kg bw of extract alone, and group VI (sham + SIL) administered with 5 mg/kg bw of sildenafil citrate. The M. pruriens and sildenafil citrate were given (gavage) once daily for a period of 60 days. At the end of 60 days, the animals were sacrificed and subjected to analysis of reactive oxygen species levels, enzymic and nonenzymic antioxidant levels, levels of NOx, histological, and histomorphometrical study of penile tissue. MAIN OUTCOME MEASURES Remedial use of M. pruriens seed extract on diabetes-induced erectile tissue damage. RESULTS Significantly high levels of oxidative stress and low levels of antioxidants in the penile tissue seem to contribute to the increased collagen deposition and fibrosis of erectile tissue in STZ rats. Relatively, there was increased damage in STZ + SIL group. Supplementation of M. pruriens in STZ + MP group has revealed the potency to overcome oxidative stress, and good preservation of penile histoarchitecture. CONCLUSION The ethanolic extract of M. pruriens seed significantly recovered or protected erectile tissue from the oxidative stress-induced degeneration by its antioxidant potentials. These findings propound to serve mankind by the treatment of diabetes-induced erectile dysfunction.
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Affiliation(s)
- Sekar Suresh
- Department of Anatomy, Dr Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
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Waldkirch ES, Ückert S, Sigl K, Satzger I, Geismar U, Langnäse K, Richter K, Sohn M, Kuczyk MA, Hedlund P. Expression of cyclic AMP-dependent protein kinase isoforms in human cavernous arteries: functional significance and relation to phosphodiesterase type 4. J Sex Med 2010; 7:2104-2111. [PMID: 20487244 DOI: 10.1111/j.1743-6109.2010.01808.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION The cyclic adenosine monophosphate-dependent protein kinase (cAK) is considered a key protein in the control of smooth muscle tone in the cardiovascular system. There is evidence that erectile dysfunction might be linked to systemic vascular disorders and arterial insufficiency, subsequently resulting in structural changes in the penile tissue. The expression and significance of cAK in human cavernous arteries (HCA) have not been evaluated. AIMS To evaluate the expression of cAK isoforms in HCA and examine the role of cAK in the cyclic adenosine monophosphate (cAMP)- and cyclic guanosine monophosphate (cGMP)-mediated control of penile vascular smooth muscle. METHODS The expression and distribution of phosphodiesterase type 4 (PDE4) and cAK isoforms in sections of HCA were investigated by means of immunohistochemistry and Western blot analysis. The effects of the cAK inhibitor Rp-8-CPT-cAMPS on the relaxation of isolated preparations of HCA (diameter > 100 µm) induced by rolipram, sildenafil, tadalafil, and vardenafil were studied using the organ bath technique. MAIN OUTCOME MEASURES Investigate the expression of cAK in relation to α-actin and PDE4 in HCA and evaluate the effects of an inhibition of cAK on the relaxation induced by inhibitors of PDE4 and PDE5 of isolated penile arteries. RESULTS Immunosignals specific for cAKIα, IIα, and IIβ were observed within the wall of HCA. Double stainings revealed colocalization of cAK with α-actin and PDE4. The expression of cAK isoforms was confirmed by Western blot analysis. The reversion of tension induced by inhibitors of PDE4 and PDE5 of isolated penile vascular tissue were attenuated significantly by Rp-8-CPT-cAMPS. CONCLUSIONS Our results demonstrate the expression of cAK isoforms in the smooth musculature of HCA and its colocalization with PDE4. A significant role for cAK in the regulation mediated by cAMP and cGMP of vascular smooth muscle tone in HCA can also be assumed.
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Affiliation(s)
- Eginhard S Waldkirch
- Hannover Medical School-Division of Surgery, Department of Urology and Urological Oncology, Hannover, Germany
| | - Stefan Ückert
- Hannover Medical School-Division of Surgery, Department of Urology and Urological Oncology, Hannover, Germany.
| | | | - Imke Satzger
- Hannover Medical School-Department of Dermatology and Allergology, Hannover, Germany
| | | | - Kristina Langnäse
- Otto-von-Guericke-University, Faculty of Medicine-Institute for Biochemistry and Cell Biology, Magdeburg, Germany
| | - Karin Richter
- Otto-von-Guericke-University, Faculty of Medicine-Institute for Biochemistry and Cell Biology, Magdeburg, Germany
| | - Michael Sohn
- Frankfurter Diakonie-Kliniken, St. Markus Academic Hospital-Department of Urology, Frankfurt am Main, Germany
| | - Markus A Kuczyk
- Hannover Medical School-Division of Surgery, Department of Urology and Urological Oncology, Hannover, Germany
| | - Petter Hedlund
- University Vita Salute, Faculty of Medicine, San Raffaele Hospital-Department of Urology, Urological Research Institute, Milan, Italy
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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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Sánchez A, Contreras C, Villalba N, Martínez P, Martínez AC, Bríones A, Salaíces M, García-Sacristán A, Hernández M, Prieto D. Altered arachidonic acid metabolism via COX-1 and COX-2 contributes to the endothelial dysfunction of penile arteries from obese Zucker rats. Br J Pharmacol 2010; 159:604-16. [PMID: 20082610 DOI: 10.1111/j.1476-5381.2009.00553.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND AND PURPOSE The aim of the current study was to investigate the role of arachidonic acid (AA) metabolism via cyclooxygenase (COX) in the endothelial dysfunction of penile arteries from pre-diabetic, obese Zucker rats (OZR). EXPERIMENTAL APPROACH Penile arteries from OZR and from lean Zucker rats (LZR) were mounted in microvascular myographs to assess vascular function and COX expression was determined by immunohistochemistry. KEY RESULTS Acetylcholine (ACh) and AA elicited relaxations that were impaired in arteries from OZR. Inhibition of both COX-1 and COX-2 reduced the relaxant effects of ACh and AA in LZR but not in OZR. Inhibitors of COX-1 and of the TXA(2)/PGH(2) (TP) receptor enhanced the relaxations induced by AA in both LZR and OZR, whereas COX-2 inhibition enhanced these responses only in OZR. TP receptor blockade did not restore ACh relaxant responses in arteries from OZR. Inhibition of COX-1 increased basal tension in OZR and this contraction was blunted by TP receptor blockade. The vasoconstrictor responses to noradrenaline were augmented by indomethacin and by COX-2 inhibition in LZR but not in OZR. Immunohistochemical staining showed that both COX-1 and COX-2 are expressed in the endothelium of penile arteries from both LZR and OZR. CONCLUSIONS AND IMPLICATIONS Vasoactive prostanoids were formed via constitutively active COX-1 and COX-2 pathways in normal rat penile arteries. Under conditions of insulin resistance, the release and/or effects of vasodilator prostanoids were impaired, contributing to the blunted endothelium-dependent vasodilatation and to the enhanced vasoconstriction.
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Affiliation(s)
- A Sánchez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
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Zhao C, Chae HJ, Kim SH, Cui WS, Lee SW, Jeon JH, Park JK. A new perfusion model for studying erectile function. J Sex Med 2010; 7:1419-28. [PMID: 20059654 DOI: 10.1111/j.1743-6109.2009.01652.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
INTRODUCTION The present study introduces a newly devised in vitro penile perfusion model, which allows the measurement of changes in intracavernosum pressure (ICP), tension, and cyclic nucleotides in penile tissue in a one-step procedure. AIMS We compared the penile perfusion model with the classical penile strip chamber model to develop the new model. METHODS We investigated the role of nitric oxide-cyclic guanosine monophosphate pathway in both systems activated by acetylcholine or electrical field stimulation (EFS). We measured cGMP (cyclic guanosine monophosphate) in the penile corpus cavernosum smooth muscle in both systems and perfusates in the penile perfusion model. We determined ICP, tension, and cGMP simultaneously in penile perfusion model during the experiments. MAIN OUTCOME MEASURES Changes of tension and cGMP in both models, and of cGMP in perfusates and of ICP in penile perfusion model. RESULTS In both systems, acetylcholine relaxed the phenylephrine-precontracted penile corpus cavernosum smooth muscle in a concentration-dependent manner. EFS decreased the tension in both models and ICP in the penile perfusion model in a frequency-dependent manner. Pretreatment with atropine, Nomega nitro-L-arginine-methyl ester (L-NAME), and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) blocked the acetylcholine-induced decrease in the tension in both models and ICP in penile perfusion model. Acetylcholine increased cGMP levels in the perfusate of penile perfusion model and the changes were attenuated by tetrodotoxin (TTX), atropine, L-NAME and ODQ. EFS increased cGMP levels of the penile corpus cavernosum smooth muscle of both models and the changes were attenuated by TTX, atropine, L-NAME, and ODQ. CONCLUSION The results indicated that the responses of penile strip and perfused penile tissue to acetylcholine and EFS were very similar in both models in terms of tension and cGMP levels. Furthermore, the new model has more advantages over the classical penile strip chamber model in measuring intracavernosum metabolic changes and ICP without interruption of the procedure.
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Affiliation(s)
- Chen Zhao
- Department of Urology, Medical School, and Institute for Medical Sciences, Chonbuk National University, and Research Institute of Clinical Medicine and CTC for Medical Device of Chonbuk National University Hospital, Jeonju 561-712, Korea
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Abstract
Erectile dysfunction (ED) affects up to 50% of men between the ages of 40 and 70. Treatment with PDE-5 inhibitors is effective in the majority of men with ED. However, PDE-5 inhibitors are not effective when levels of nitric oxide (NO), the principle mediator of erection, are low. The pharmacologic actions of three new potential treatments for ED are discussed in this paper: (1) sGC stimulators/activators, (2) Rho-kinase inhibitors, and (3) sodium nitrite.
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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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Kuo P, Gentilcore D, Nair N, Stevens JE, Wishart JM, Lange K, Gilja OH, Hausken T, Horowitz M, Jones KL, Rayner CK. The nitric oxide synthase inhibitor, Ng-nitro-L-arginine-methyl-ester, attenuates the delay in gastric emptying induced by hyperglycaemia in healthy humans. Neurogastroenterol Motil 2009; 21:1175-e103. [PMID: 19460102 DOI: 10.1111/j.1365-2982.2009.01321.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The aim of this study was to determine whether the nitric oxide (NO) synthase inhibitor, N(g)-nitro-L-arginine-methyl-ester (L-NAME), reverses the effects of acute hyperglycaemia on gastric emptying and antropyloroduodenal (APD) motility. The study had a four-way randomized crossover (hyperglycaemia vs euglycaemia; L-NAME vs placebo) design in a clinical laboratory setting. Seven healthy volunteers [four males; age 30.3 +/- 3.8 years; body mass index (BMI) 23.6 +/- 1.2 kg m(-2)] were the study subjects. After positioning a transnasal manometry catheter across the pylorus, the blood glucose concentration was maintained at either 15 or 5 mmol L(-1) using a glucose/insulin clamp. An intravenous infusion of L-NAME (180 microg kg(-1 )h(-1)) or placebo (0.9% saline) was commenced (T = -30 min) and continued for 150 min. At T = -2 min, subjects ingested a drink containing 50 g of glucose made up to 300 mL with water. Gastric emptying was measured using 3D ultrasound, and APD motility using manometry. Hyperglycaemia slowed gastric emptying (P < 0.05), and this effect was abolished by L-NAME. L-NAME had no effect on gastric emptying during euglycaemia. Hyperglycaemia suppressed fasting antral motility [motility index: 3.9 +/- 0.8 (hyperglycaemia) vs 6.5 +/- 0.6 (euglycaemia); P < 0.01]; l-NAME suppressed postprandial antral motility [motility index: 3.6 +/- 0.2 (L-NAME) vs 5.1 +/- 0.2 (placebo); P < 0.001]. Postprandial basal pyloric pressure was higher during hyperglycaemia (P < 0.001), and lower after administration of L-NAME (P < 0.001). Slowing of gastric emptying induced by hyperglycaemia is mediated by NO, and may involve the modulation of tonic pyloric activity.
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Affiliation(s)
- P Kuo
- Discipline of Medicine, Royal Adelaide Hospital, University of Adelaide, Adelaide, Australia.
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Vlachopoulos C, Ioakeimidis N, Terentes-Printzios D, Rokkas K, Aznaouridis K, Baou K, Bratsas A, Fassoulakis C, Stefanadis C. Amino-Terminal Pro-C-Type Natriuretic Peptide is Associated with the Presence, Severity, and Duration of Vasculogenic Erectile Dysfunction. Eur Urol 2009; 56:552-8. [DOI: 10.1016/j.eururo.2008.11.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 11/12/2008] [Indexed: 01/31/2023]
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Villalba N, Martínez P, Bríones AM, Sánchez A, Salaíces M, García-Sacristán A, Hernández M, Benedito S, Prieto D. Differential structural and functional changes in penile and coronary arteries from obese Zucker rats. Am J Physiol Heart Circ Physiol 2009; 297:H696-707. [PMID: 19542483 DOI: 10.1152/ajpheart.01308.2008] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Erectile dysfunction frequently coexists with coronary artery disease and has been proposed as a potential marker for silent coronary artery disease in type 2 diabetes. In the present study, we comparatively assessed the structural and functional changes of both penile arteries (PAs) and coronary arteries (CAs) from a prediabetic animal model. PAs and CAs from 17- to 18-wk-old obese Zucker rats (OZRs) and from their control counterparts [lean Zucker rats (LZRs)] were mounted in microvascular myographs to evaluate vascular function, and stained arteries were subjected to morphometric analysis. Endothelial nitric oxide (NO) synthase (eNOS) protein expression was also assessed. The internal diameter was reduced and the wall-to-lumen ratio was increased in PAs from OZRs, but structure was preserved in CAs. ACh-elicited relaxations were severely impaired in PAs but not in CAs from OZRs, although eNOS expression was unaltered. Contractions to norepinephrine and 5-HT were significantly enhanced in both PAs and CAs, respectively, from OZRs. Blockade of NOS abolished endothelium-dependent relaxations in PAs and CAs and potentiated norepinephrine and 5-HT contractions in arteries from LZRs but not from OZRs. The vasodilator response to the phosphodiesterase 5 inhibitor sildenafil was reduced in both PAs and CAs from OZRs. Pretreatment with SOD reduced the enhanced vasoconstriction in both PAs and CAs from OZRs but did not restore ACh-induced relaxations in PAs. In conclusion, the present results demonstrate vascular inward remodeling in PAs and a differential impairment of endothelial relaxant responses in PAs and CAs from insulin-resistant OZRs. Enhanced superoxide production and reduced basal NO activity seem to underlie the augmented vasoconstriction in both PAs and CAs. The severity of the structural and functional abnormalities in PAs might anticipate the vascular dysfunction of the more preserved coronary vascular bed.
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Affiliation(s)
- Nuria Villalba
- Department of Physiology, Faculty of Pharmacy, Faculty of Veterinary Sciences, Universidad Complutense, Madrid, Spain
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Vardi Y, Dayan L, Apple B, Gruenwald I, Ofer Y, Jacob G. Penile and Systemic Endothelial Function in Men with and without Erectile Dysfunction. Eur Urol 2009; 55:979-85. [DOI: 10.1016/j.eururo.2008.07.041] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2008] [Accepted: 07/17/2008] [Indexed: 01/27/2023]
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Gur S, Kadowitz PJ, Hellstrom WJG. A critical appraisal of erectile function in animal models of diabetes mellitus. ACTA ACUST UNITED AC 2009; 32:93-114. [DOI: 10.1111/j.1365-2605.2008.00928.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Grgic I, Kaistha BP, Hoyer J, Köhler R. Endothelial Ca+-activated K+ channels in normal and impaired EDHF-dilator responses--relevance to cardiovascular pathologies and drug discovery. Br J Pharmacol 2009; 157:509-26. [PMID: 19302590 DOI: 10.1111/j.1476-5381.2009.00132.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The arterial endothelium critically contributes to blood pressure control by releasing vasodilating autacoids such as nitric oxide, prostacyclin and a third factor or pathway termed 'endothelium-derived hyperpolarizing factor' (EDHF). The nature of EDHF and EDHF-signalling pathways is not fully understood yet. However, endothelial hyperpolarization mediated by the Ca(2+)-activated K(+) channels (K(Ca)) has been suggested to play a critical role in initializing EDHF-dilator responses in conduit and resistance-sized arteries of many species including humans. Endothelial K(Ca) currents are mediated by the two K(Ca) subtypes, intermediate-conductance K(Ca) (KCa3.1) (also known as, a.k.a. IK(Ca)) and small-conductance K(Ca) type 3 (KCa2.3) (a.k.a. SK(Ca)). In this review, we summarize current knowledge about endothelial KCa3.1 and KCa2.3 channels, their molecular and pharmacological properties and their specific roles in endothelial function and, particularly, in the EDHF-dilator response. In addition we focus on recent experimental evidences derived from KCa3.1- and/or KCa2.3-deficient mice that exhibit severe defects in EDHF signalling and elevated blood pressures, thus highlighting the importance of the KCa3.1/KCa2.3-EDHF-dilator system for blood pressure control. Moreover, we outline differential and overlapping roles of KCa3.1 and KCa2.3 for EDHF signalling as well as for nitric oxide synthesis and discuss recent evidence for a heterogeneous (sub) cellular distribution of KCa3.1 (at endothelial projections towards the smooth muscle) and KCa2.3 (at inter-endothelial borders and caveolae), which may explain their distinct roles for endothelial function. Finally, we summarize the interrelations of altered KCa3.1/KCa2.3 and EDHF system impairments with cardiovascular disease states such as hypertension, diabetes, dyslipidemia and atherosclerosis and discuss the therapeutic potential of KCa3.1/KCa2.3 openers as novel types of blood pressure-lowering drugs.
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Affiliation(s)
- Ivica Grgic
- Department of Internal Medicine-Nephrology, Philipps-University, Marburg, Germany
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Endothelium-derived hyperpolarizing factor in vascular physiology and cardiovascular disease. Atherosclerosis 2009; 202:330-44. [DOI: 10.1016/j.atherosclerosis.2008.06.008] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 05/16/2008] [Accepted: 06/11/2008] [Indexed: 12/20/2022]
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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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Abstract
Tumescence occurs as a result of nitric oxide (NO)-mediated smooth muscle relaxation of the erectile tissue leading to engorgement of the corpus cavernosum. The process is initiated by neuronal NO release and maintained by NO released by the local vascular endothelium. Erectile dysfunction (ED) affects 30% to 40% of diabetic men and occurs as a result of endothelial dysfunction and autonomic neuropathy. The close association with endothelial dysfunction means ED is an early marker of cardiovascular risk. Managing ED is easy and must be part of a diabetes care service. Phosphodiesterase type 5 inhibitors are the treatment of choice, but are effective in only 50% to 60% of diabetic men. The reasons for nonresponsiveness remain uncertain and research is needed in this area. There has been much recent interest in the potential relationship between late-onset hypogonadism and diabetes, but there is no evidence of a causal relationship and the evidence in favor of treating borderline hypogonadism in diabetes is limited.
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Affiliation(s)
- David Price
- Morriston Hospital, ABM University Trust, Swansea, United Kingdom.
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Costa C, Soares R, Castela A, Adães S, Hastert V, Vendeira P, Virag R. Increased endothelial apoptotic cell density in human diabetic erectile tissue--comparison with clinical data. J Sex Med 2008; 6:826-35. [PMID: 19067790 DOI: 10.1111/j.1743-6109.2008.01110.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Erectile dysfunction (ED) is a common complication of diabetes. Endothelial cell (EC) dysfunction is one of the main mechanisms of diabetic ED. However, loss of EC integrity has never been assessed in human diabetic corpus cavernosum. AIM To identify and quantify apoptotic cells in human diabetic and normal erectile tissue and to compare these results with each patient's clinical data and erection status. METHODS Eighteen cavernosal samples were collected, 13 from diabetics with ED and 5 from nondiabetic individuals. Cavernosal structure and cell proliferation status were evaluated by immunohistochemistry. Tissue integrity was assessed by terminal transferase dUTP nick end labeling assay, an index of apoptotic cell density (ACD) established and compared with each patient age, type of diabetes, arterial risk factors number, arterial/veno-occlusive disease, response to intracavernous vasoactive injections (ICI), and penile nitric oxide release test (PNORT). MAIN OUTCOME MEASURES Establish an index of ACD and correlate those results with patient clinical data. RESULTS Nondiabetic samples presented few scattered cells in apoptosis and an ACD of 7.15 +/- 0.44 (mean apoptotic cells/tissue area mm(2) +/- standard error). The diabetic group showed an increased ACD of 23.82 +/- 1.53, and apoptotic cells were located specifically at vascular sites. Rehabilitation of these endothelial lesions seemed impaired, as no evidence of EC proliferation was observed. Furthermore, higher ACD in diabetic individuals correlated to poor response to PNORT and to ICI. CONCLUSIONS We provided evidence for the first time that loss of cavernosal EC integrity is a crucial event involved in diabetic ED. Furthermore, we were able to establish a threshold between ACD values and cavernosal tissue functionality, as assessed by PNORT and vasoactive ICI.
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Affiliation(s)
- Carla Costa
- Laboratory for Molecular Cell Biology, Faculty of Medicine of the University of Porto, Porto, Portugal
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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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Park Y, Capobianco S, Gao X, Falck JR, Dellsperger KC, Zhang C. Role of EDHF in type 2 diabetes-induced endothelial dysfunction. Am J Physiol Heart Circ Physiol 2008; 295:H1982-8. [PMID: 18790831 DOI: 10.1152/ajpheart.01261.2007] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Endothelium-derived hyperpolarizing factor (EDHF) plays a crucial role in modulating vasomotor tone, especially in microvessels when nitric oxide-dependent control is compromised such as in diabetes. Epoxyeicosatrienoic acids (EETs), potassium ions (K+), and hydrogen peroxide (H2O2) are proposed as EDHFs. However, the identity (or identities) of EDHF-dependent endothelial dilators has not been clearly elucidated in diabetes. We assessed the mechanisms of EDHF-induced vasodilation in wild-type (WT, normal), db/db (advanced type 2 diabetic) mice, and db/db mice null for TNF (dbTNF-/dbTNF-). In db/db mice, EDHF-induced vasodilation [ACh-induced vasodilation in the presence of N(G)-nitro-L-arginine methyl ester (L-NAME, 10 micromol/l) and prostaglandin synthase inhibitor indomethacin (Indo, 10 mumol/l)] was diminished after the administration of catalase (an enzyme that selectively dismutates H2O2 to water and oxygen, 1,000 U/ml); administration of the combination of charybdotoxin (a nonselective blocker of intermediate-conductance Ca2+-activated K+ channels, 10 micromol/l) and apamin (a selective blocker of small-conductance Ca2+-activated K+ channels, 50 micromol/l) also attenuated EDHF-induced vasodilation, but the inhibition of EETs synthesis [14,15-epoxyeicosa-5(Z)-enoic acid; 10 mumol/l] did not alter EDHF-induced vasodilation. In WT controls, EDHF-dependent vasodilation was significantly diminished after an inhibition of K+ channel, EETs synthesis, or H2O2 production. Our molecular results indicate that mRNA and protein expression of interleukin-6 (IL-6) were greater in db/db versus WT and dbTNF-/dbTNF- mice, but neutralizing antibody to IL-6 (anti-IL-6; 0.28 mg.ml(-1).kg(-1) ip for 3 days) attenuated IL-6 expression in db/db mice. The incubation of the microvessels with IL-6 (5 ng/ml) induced endothelial dysfunction in the presence of l-NAME and Indo in WT mice, but anti-IL-6 restored ACh-induced vasodilation in the presence of L-NAME and Indo in db/db mice. In db(TNF-)/db(TNF-) mice, EDHF-induced vasodilation was greater and comparable with controls, but IL-6 decreased EDHF-mediated vasodilation. Our results indicate that EDHF compensates for diminished NO-dependent dilation in IL-6-induced endothelial dysfunction by the activation of H2O2 or a K+ channel in type 2 diabetes.
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Affiliation(s)
- Yoonjung Park
- Department of Internal Medicine, Medical Pharmacology and Physiology and Nutritional Science, Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO 65211, USA
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Bellien J, Thuillez C, Joannides R. Contribution of endothelium-derived hyperpolarizing factors to the regulation of vascular tone in humans. Fundam Clin Pharmacol 2008; 22:363-77. [DOI: 10.1111/j.1472-8206.2008.00610.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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