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Liu XC, Zhou PK. Tissue Reactions and Mechanism in Cardiovascular Diseases Induced by Radiation. Int J Mol Sci 2022; 23:ijms232314786. [PMID: 36499111 PMCID: PMC9738833 DOI: 10.3390/ijms232314786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/16/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
The long-term survival rate of cancer patients has been increasing as a result of advances in treatments and precise medical management. The evidence has accumulated that the incidence and mortality of non-cancer diseases have increased along with the increase in survival time and long-term survival rate of cancer patients after radiotherapy. The risk of cardiovascular disease as a radiation late effect of tissue damage reactions is becoming a critical challenge and attracts great concern. Epidemiological research and clinical trials have clearly shown the close association between the development of cardiovascular disease in long-term cancer survivors and radiation exposure. Experimental biological data also strongly supports the above statement. Cardiovascular diseases can occur decades post-irradiation, and from initiation and development to illness, there is a complicated process, including direct and indirect damage of endothelial cells by radiation, acute vasculitis with neutrophil invasion, endothelial dysfunction, altered permeability, tissue reactions, capillary-like network loss, and activation of coagulator mechanisms, fibrosis, and atherosclerosis. We summarize the most recent literature on the tissue reactions and mechanisms that contribute to the development of radiation-induced cardiovascular diseases (RICVD) and provide biological knowledge for building preventative strategies.
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Ex Vivo Radiation Leads to Opposing Neurite Growth in Whole Ganglia vs Dissociated Cultured Pelvic Neurons. J Sex Med 2020; 17:1423-1433. [DOI: 10.1016/j.jsxm.2020.04.385] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 04/21/2020] [Accepted: 04/24/2020] [Indexed: 11/19/2022]
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Baselet B, Sonveaux P, Baatout S, Aerts A. Pathological effects of ionizing radiation: endothelial activation and dysfunction. Cell Mol Life Sci 2019; 76:699-728. [PMID: 30377700 PMCID: PMC6514067 DOI: 10.1007/s00018-018-2956-z] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 10/19/2018] [Accepted: 10/23/2018] [Indexed: 01/13/2023]
Abstract
The endothelium, a tissue that forms a single layer of cells lining various organs and cavities of the body, especially the heart and blood as well as lymphatic vessels, plays a complex role in vascular biology. It contributes to key aspects of vascular homeostasis and is also involved in pathophysiological processes, such as thrombosis, inflammation, and hypertension. Epidemiological data show that high doses of ionizing radiation lead to cardiovascular disease over time. The aim of this review is to summarize the current knowledge on endothelial cell activation and dysfunction after ionizing radiation exposure as a central feature preceding the development of cardiovascular diseases.
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Affiliation(s)
- Bjorn Baselet
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK•CEN), Mol, Belgium
- Institute of Experimental and Clinical Research (IREC), Pole of Pharmacology and Therapeutics, Université catholique de Louvain (UCL), Brussels, Belgium
| | - Pierre Sonveaux
- Institute of Experimental and Clinical Research (IREC), Pole of Pharmacology and Therapeutics, Université catholique de Louvain (UCL), Brussels, Belgium
| | - Sarah Baatout
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK•CEN), Mol, Belgium
- Department of Molecular Biotechnology, Ghent University, Ghent, Belgium
| | - An Aerts
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK•CEN), Mol, Belgium.
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Powers SA, Odom MR, Pak ES, Moomaw MA, Ashcraft KA, Koontz BF, Hannan JL. Prostate-Confined Radiation Decreased Pelvic Ganglia Neuronal Survival and Outgrowth. J Sex Med 2019; 16:27-41. [DOI: 10.1016/j.jsxm.2018.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/10/2018] [Accepted: 11/16/2018] [Indexed: 12/15/2022]
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Kaplan M, Kılınç A, Ozturk S, Ilhan N, Gurocak S, Gonen M. Effect of radiation on brain tissue endothelin-1 level and tumor development. Asian J Neurosurg 2017; 12:185-188. [PMID: 28484527 PMCID: PMC5409363 DOI: 10.4103/1793-5482.145575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Radiotherapy causes injury in the endothelial cells of blood vessels and the production of vasoactive amines such as endothelin-1 (ET-1). ET-1 is an important peptide in cancer development. In this study, the effects of radiation on brain tissue ET-1 level were evaluated. Is it possible to suggest a mechanism using ET-1 level in the production of this adverse effect? In this paper, the relationship between the development of brain tumors and the ET-1 level has been discussed. MATERIALS AND METHODS Twenty-eight adult Sprague Dawley rats were used in the experiments. The rats were divided into four groups (n = 7) as follows: control group: radiation was not applied during the experiment; Group 1: Decapitated on the 1st day following radiation; Group 2: Decapitated on the 7th day following radiation; and Group 3: Decapitated on the 30th day following radiation. ET-1 levels were measured with enzyme-linked immunosorbent assay (ELISA) method. The t-test, variance analysis, and Tukey honestly significant difference (HSD) tests were used in the statistical analysis. A value of P < 0.05 was accepted as significant. RESULTS No statistical differences were observed in the tissue ET-1 levels between the control group and other groups. According to the variance analysis and Tukey test, the differences between the groups were not significant. CONCLUSION We observed in this study that the effects of radiation on brain tumor development or malignant transformation are not mediated by ET-1 levels. In addition, these results support the hypothesis of the fact that medical treatment with ET-1 antagonists in clinical cases receiving radiotheraphy is unnecessary.
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Affiliation(s)
- Metin Kaplan
- Department of Neurosurgery, Firat University, Elazig, Turkey
| | - Ahmet Kılınç
- Department of Neurosurgery, Firat University, Elazig, Turkey
| | - Sait Ozturk
- Department of Neurosurgery, Firat University, Elazig, Turkey
| | - Nevin Ilhan
- Department of Biochemistry, Firat University, Elazig, Turkey
| | - Simay Gurocak
- Department of Radiation Oncology, Inonu University, Malatya, Turkey
| | - Murat Gonen
- Department of Neurology, Firat University, Elazig, Turkey
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Nolan MW, Marolf AJ, Ehrhart EJ, Rao S, Kraft SL, Engel S, Yoshikawa H, Golden AE, Wasserman TH, LaRue SM. Pudendal nerve and internal pudendal artery damage may contribute to radiation-induced erectile dysfunction. Int J Radiat Oncol Biol Phys 2015; 91:796-806. [PMID: 25752394 DOI: 10.1016/j.ijrobp.2014.12.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 12/08/2014] [Accepted: 12/10/2014] [Indexed: 11/29/2022]
Abstract
PURPOSE/OBJECTIVES Erectile dysfunction is common after radiation therapy for prostate cancer; yet, the etiopathology of radiation-induced erectile dysfunction (RI-ED) remains poorly understood. A novel animal model was developed to study RI-ED, wherein stereotactic body radiation therapy (SBRT) was used to irradiate the prostate, neurovascular bundles (NVB), and penile bulb (PB) of dogs. The purpose was to describe vascular and neurogenic injuries after the irradiation of only the NVB or the PB, and after irradiation of all 3 sites (prostate, NVB, and PB) with varying doses of radiation. METHODS AND MATERIALS Dogs were treated with 50, 40, or 30 Gy to the prostate, NVB, and PB, or 50 Gy to either the NVB or the PB, by 5-fraction SBRT. Electrophysiologic studies of the pudendal nerve and bulbospongiosus muscles and ultrasound studies of pelvic perfusion were performed before and after SBRT. The results of these bioassays were correlated with histopathologic changes. RESULTS SBRT caused slowing of the systolic rise time, which corresponded to decreased arterial patency. Alterations in the response of the internal pudendal artery to vasoactive drugs were observed, wherein SBRT caused a paradoxical response to papaverine, slowing the systolic rise time after 40 and 50 Gy; these changes appeared to have some dose dependency. The neurofilament content of penile nerves was also decreased at high doses and was more profound when the PB was irradiated than when the NVB was irradiated. These findings are coincident with slowing of motor nerve conduction velocities in the pudendal nerve after SBRT. CONCLUSIONS This is the first report in which prostatic irradiation was shown to cause morphologic arterial damage that was coincident with altered internal pudendal arterial tone, and in which decreased motor function in the pudendal nerve was attributed to axonal degeneration and loss. Further investigation of the role played by damage to these structures in RI-ED is warranted.
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Affiliation(s)
- Michael W Nolan
- Department of Clinical Sciences, and Center for Comparative Medicine and Translational Research, North Carolina State University, Raleigh, North Carolina; Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado.
| | - Angela J Marolf
- Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado
| | - E J Ehrhart
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Sangeeta Rao
- Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado
| | - Susan L Kraft
- Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado
| | - Stephanie Engel
- Department of Clinical Sciences, Colorado State University, Fort Collins, Colorado
| | - Hiroto Yoshikawa
- Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado
| | - Anne E Golden
- Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado
| | - Todd H Wasserman
- Department of Radiation Oncology, Washington University, St. Louis, Missouri
| | - Susan M LaRue
- Department of Environmental and Radiologic Health Sciences, Colorado State University, Fort Collins, Colorado
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Kimura M, Zodda AR, Mahmood J, Das SK, Nguyen GB, Jackson IL, Vujaskovic Z. Pilot Study Evaluating a Rat Model of Radiation-induced Erectile Dysfunction Using an Image-guided Microirradiator. Urology 2015; 85:1214.e1-1214.e6. [PMID: 25772480 DOI: 10.1016/j.urology.2014.12.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 11/21/2014] [Accepted: 12/12/2014] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To establish a feasible rat model of radiation-induced erectile dysfunction after targeted prostate irradiation using an image-guided irradiation unit specially designed for small-animal radiation research. METHODS The X-RAD 225Cx research platform was used in the present study. We first performed quality assurance testing using a rat cadaver. After confirming dosimetry, 24 age-matched, young, adult, male rats were assigned to sham radiation or radiation to the prostate with doses of 15, 20, or 25 Gy. To confirm appropriate prostate irradiation, physiological erectile function was evaluated using intracavernous pressure (ICP) measurements with cavernous nerve electrical stimulation at 9 weeks after radiotherapy. Each animal was weighed at the time of ICP measurement. In addition, we investigated the cyclic guanosine monophosphate level in the penile cavernosa using a commercial enzyme-linked immunosorbent assay kit. RESULTS Quality assurance results confirmed the accuracy of the irradiation technique. Dose-dependent decreases in ICP in irradiated rats were observed without major toxicity. No difference in body weight was noted among the experimental groups. Cyclic guanosine monophosphate levels were significantly decreased in the group that received 25 Gy compared with the age-matched sham-irradiated group. CONCLUSION High-precision imaging and targeting capabilities provided by the micro-IGRT platform enable us to develop a reproducible animal model of radiation-induced erectile dysfunction in prostate cancer research.
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Affiliation(s)
- Masaki Kimura
- Department of Urology, Teikyo University, Kaga, Itabashi, Japan
| | - Andrew R Zodda
- Division of Translational Radiation Sciences, Department of Radiation Oncology, University of Maryland, Baltimore, MD
| | - Javed Mahmood
- Division of Translational Radiation Sciences, Department of Radiation Oncology, University of Maryland, Baltimore, MD
| | - Shiva K Das
- Department of Radiation Oncology, Duke University, Durham, NC
| | - Giao B Nguyen
- Division of Radiation Safety, Department of Radiology, Duke University, Durham, NC
| | - Isabel L Jackson
- Division of Translational Radiation Sciences, Department of Radiation Oncology, University of Maryland, Baltimore, MD
| | - Zeljko Vujaskovic
- Division of Translational Radiation Sciences, Department of Radiation Oncology, University of Maryland, Baltimore, MD.
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Abstract
Animal models have contributed to a great extent to understanding and advancement in the field of sexual medicine. Many current medical and surgical therapies in sexual medicine have been tried based on these animal models. Extensive literature search revealed that the compiled information is limited. In this review, we describe various experimental models of erectile dysfunction (ED) encompassing their procedures, variables of assessment, advantages and disadvantages. The search strategy consisted of review of PubMed based articles. We included original research work and certain review articles available in PubMed database. The search terms used were “ED and experimental models,” “ED and nervous stimulation,” “ED and cavernous nerve stimulation,” “ED and central stimulation,” “ED and diabetes mellitus,” “ED and ageing,” “ED and hypercholesteremia,” “ED and Peyronie's disease,” “radiation induced ED,” “telemetric recording,” “ED and mating test” and “ED and non-contact erection test.”
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Affiliation(s)
- Snehlata V Gajbhiye
- Departments of Pharmacology and Therapeutics, Seth Gordhandas Sundardas Medical College and King Edward Memorial Hospital, Parel, Mumbai, Maharashtra, India
| | - Kshitij S Jadhav
- Departments of Pharmacology and Therapeutics, Seth Gordhandas Sundardas Medical College and King Edward Memorial Hospital, Parel, Mumbai, Maharashtra, India
| | - Padmaja A Marathe
- Departments of Pharmacology and Therapeutics, Seth Gordhandas Sundardas Medical College and King Edward Memorial Hospital, Parel, Mumbai, Maharashtra, India
| | - Dattatray B Pawar
- Departments of Pharmacology and Therapeutics, Seth Gordhandas Sundardas Medical College and King Edward Memorial Hospital, Parel, Mumbai, Maharashtra, India
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Oberley-Deegan RE, Steffan JJ, Rove KO, Pate KM, Weaver MW, Spasojevic I, Frederick B, Raben D, Meacham RB, Crapo JD, Koul HK. The antioxidant, MnTE-2-PyP, prevents side-effects incurred by prostate cancer irradiation. PLoS One 2012; 7:e44178. [PMID: 22984473 PMCID: PMC3440381 DOI: 10.1371/journal.pone.0044178] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 08/02/2012] [Indexed: 11/18/2022] Open
Abstract
Prostate cancer is the most commonly diagnosed cancer, with an estimated 240,000 new cases reported annually in the United States. Due to early detection and advances in therapies, more than 90% of patients will survive 10 years post diagnosis and treatment. Radiation is a treatment option often used to treat localized disease; however, while radiation is very effective at killing tumor cells, normal tissues are damaged as well. Potential side-effects due to prostate cancer-related radiation therapy include bowel inflammation, erectile dysfunction, urethral stricture, rectal bleeding and incontinence. Currently, radiation therapy for prostate cancer does not include the administration of therapeutic agents to reduce these side effects and protect normal tissues from radiation-induced damage. In the current study, we show that the small molecular weight antioxidant, MnTE-2-PyP, protects normal tissues from radiation-induced damage in the lower abdomen in rats. Specifically, MnTE-2-PyP protected skin, prostate, and testes from radiation-induced damage. MnTE-2-PyP also protected from erectile dysfunction, a persistent problem regardless of the type of radiation techniques used because the penile neurovascular bundles lay in the peripheral zones of the prostate, where most prostate cancers reside. Based on previous studies showing that MnTE-2-PyP, in combination with radiation, further reduces subcutaneous tumor growth, we believe that MnTE-2-PyP represents an excellent radioprotectant in combination radiotherapy for cancer in general and specifically for prostate cancer.
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Affiliation(s)
- Rebecca E Oberley-Deegan
- Pulmonary Division, Department of Medicine, National Jewish Health, Denver, Colorado, United States of America
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Qiu X, Villalta J, Ferretti L, Fandel TM, Albersen M, Lin G, Dai Y, Lue TF, Lin CS. Effects of intravenous injection of adipose-derived stem cells in a rat model of radiation therapy-induced erectile dysfunction. J Sex Med 2012; 9:1834-41. [PMID: 22548750 DOI: 10.1111/j.1743-6109.2012.02753.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Radiation therapy (RT) for prostate cancer is frequently associated with posttreatment erectile dysfunction (ED). AIM To investigate whether injection of adipose-derived stem cells (ADSCs) can ameliorate RT-associated ED. METHODS Thirty male rats were divided into three groups. The control + phosphate-buffered saline (PBS) group received tail-vein injection of PBS. The radiation + PBS group received radiation over the prostate and tail-vein injection of PBS. The radiation + ADSC group received radiation over the prostate and tail-vein injection of ADSCs, which were labeled with 5-ethynyl-2-deoxyuridine (EdU). Seventeen weeks later, erectile function was evaluated by intracavernous pressure (ICP) in response to electrostimulation of cavernous nerves (CNs). Penile tissue and major pelvic ganglia (MPG) were examined by immunofluorescence (IF) and EdU staining. MAIN OUTCOME MEASURES Erectile function was measured by ICP. Protein expression was examined by IF, followed by image analysis and quantification. RESULTS Radiation over the prostate caused a significant decrease in erectile function and in the expression of neuronal nitric oxide synthase (nNOS) in penis and MPG. Cavernous smooth muscle (CSM) but not endothelial content was also reduced. Injection of ADSCs significantly restored erectile function, nNOS expression, and CSM content in the irradiated rats. EdU-positive cells were visible in MPG. CONCLUSIONS Radiation appears to cause ED via CN injury. ADSC injection can restore erectile function via CN regeneration.
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Affiliation(s)
- Xuefeng Qiu
- Knuppe Molecular Urology Laboratory, Department of Urology, School of Medicine, University of California, San Francisco, CA 94143-0738, USA
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Kimura M, Rabbani ZN, Zodda AR, Yan H, Jackson IL, Polascik TJ, Donatucci CF, Moul JW, Vujaskovic Z, Koontz BF. Role of oxidative stress in a rat model of radiation-induced erectile dysfunction. J Sex Med 2012; 9:1535-49. [PMID: 22489731 DOI: 10.1111/j.1743-6109.2012.02716.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Chronic oxidative stress is one of the major factors playing an important role in radiation-induced normal tissue injury. However, the role of oxidative stress in radiation-induced erectile dysfunction (ED) has not been fully investigated. Aims. To investigate role of oxidative stress after prostate-confined irradiation in a rat model of radiation-induced ED. METHODS Fifty-four young adult male rats (10-12 weeks of age) were divided into age-matched sham radiotherapy (RT) and RT groups. Irradiated animals received prostate-confined radiation in a single 20 Gy fraction. MAIN OUTCOME MEASURES Intracavernous pressure (ICP) measurements with cavernous nerve electrical stimulation were conducted at 2, 4, and 9 weeks following RT. The protein expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits (Nox4 and gp91(phox)), markers of oxidative DNA damage (8-hydroxy-2'-deoxyguanosine [8-OHdG]), lipid peroxidation (4-hydroxynonenal [4HNE]), and inflammatory response including inducible nitric oxide synthase, macrophage activation (ED-1), and nitrotyrosine, and endogenous antioxidant defense by nuclear factor erythroid 2-related factor (Nrf2) were evaluated in irradiated prostate tissue and corpora cavernosa (CC). In addition, we investigated the relationships between results of ICP/mean arterial pressure (MAP) ratios and expression level of oxidative stress markers. RESULTS In the RT group, hemodynamic functional studies demonstrated a significant time-dependent decrease in ICP. Increased expression of Nox4, gp91(phox), 8-OHdG, and 4HNE were observed in the prostate and CC after RT. Similarly, expressions of inflammatory markers were significantly increased. There was a trend for increased Nrf2 after 4 weeks. ICP/MAP ratio negatively correlated with higher expression level of oxidative markers. CONCLUSION NADPH oxidase activation and chronic oxidative stress were observed in irradiated prostate tissue and CC, which correlated with lower ICP/MAP ratio. Persistent inflammatory responses were also found in both tissues after RT. These findings suggest that oxidative stress plays a crucial role in the development of radiation-induced ED.
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Affiliation(s)
- Masaki Kimura
- Division of Urologic Surgery, Department of Surgery and Duke Prostate Center, Duke University Medical Center, Durham, NC, USA.
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Williams SK, melman A. Novel therapeutic targets for erectile dysfunction. Maturitas 2012; 71:20-7. [DOI: 10.1016/j.maturitas.2011.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 11/07/2011] [Indexed: 11/15/2022]
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The promise of inhibition of smooth muscle tone as a treatment for erectile dysfunction: where are we now? Int J Impot Res 2011; 24:49-60. [PMID: 21975566 DOI: 10.1038/ijir.2011.49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ten years ago, the inhibition of Rho kinase by intracavernosal injection of Y-27632 was found to induce an erectile response. This effect did not require activation of nitric oxide-mediated signaling, introducing a novel target pathway for the treatment of erectile dysfunction (ED), with potential added benefit in cases where nitric oxide bioavailability is attenuated (and thus phosphodiesterase type 5 (PDE5) inhibitors are less efficacious). Rho-kinase antagonists are currently being developed and tested for a wide range of potential uses. The inhibition of this calcium-sensitizing pathway results in blood vessel relaxation. It is also possible that blockade of additional smooth muscle contractile signaling mechanisms may have the same effect. In this review, we conducted an extensive search of pertinent literature using PUBMED. We have outlined the various pathways involved in the maintenance of penile smooth muscle tone and discussed the current potential benefit for the pharmacological inhibition of these targets for the treatment of ED.
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Kimura M, Yan H, Rabbani Z, Satoh T, Baba S, Yin FF, Polascik TJ, Donatucci CF, Vujaskovic Z, Koontz BF. Radiation-induced erectile dysfunction using prostate-confined modern radiotherapy in a rat model. J Sex Med 2011; 8:2215-26. [PMID: 21679303 DOI: 10.1111/j.1743-6109.2011.02351.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION The mechanisms of radiation-induced erectile dysfunction (ED) are unclear, as clinical studies are limited, and previous animal models were based on wide-field irradiation, which does not model current radiotherapy (RT) techniques. AIMS To perform functional and morphological analyses of erectile function (EF) utilizing image-guided stereotactic prostate-confined RT in a rat model. METHODS Sixty young adult male rats aged 10-12 weeks old were divided into age-matched sham and RT groups. A single 20-Gy fraction to the prostate was delivered to RT animals. Penile bulb, shaft, and testes were excluded from treatment fields. MAIN OUTCOME MEASURES Bioassay and intracavernous pressure (ICP) measurements were conducted at 2, 4, and 9 weeks following RT. Perfusion analysis of the corpora cavernosa (CC) was conducted using Hoechst injected prior to sacrifice. Penile shaft and cavernous nerve (CN) were evaluated by immunohistochemistry. Plasma testosterone level was analyzed using a testosterone enzyme-linked immunosorbent assay (ELISA) assay kit. RESULTS Irradiated animals demonstrated statistically significant time-dependent functional impairment of EF by bioassay and ICP measurement from 4 weeks. Neuronal nitric oxide synthase (NOS) expression was decreased in CN by 4 weeks. In CC, expression levels of anti-alpha smooth muscle actin and endothelial NOS were significantly decreased at 9 weeks. In penile dorsal vessels, smooth muscle/collagen ratio was significantly decreased at 4 and 9 weeks. Additionally, Hoechst perfusion showed time-dependent decrease in CC of RT animals, whereas CD31 expression was not affected. No toxicities were noted; testosterone levels were similar in both groups. CONCLUSION We demonstrated time-dependent ED following image-guided stereotactic RT. Our results imply that reduction of neuronal NOS expression in cavernous nerve could trigger consecutive reduction of smooth muscle content as well as blood perfusion in CC that resulted in corporal veno-occlusive dysfunction. Present study could be a cornerstone to future research that may bring comprehensive scientific understanding of radiation-induced ED.
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Affiliation(s)
- Masaki Kimura
- Division of Urologic Surgery, Department of Surgery and Duke Prostate Center, Duke University Medical Center, Durham, NC 27710, USA
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Endothelins & erectile dysfunction. Pharmacol Res 2011; 63:496-501. [DOI: 10.1016/j.phrs.2010.12.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 12/16/2010] [Accepted: 12/17/2010] [Indexed: 11/23/2022]
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Koontz BF, Yan H, Kimura M, Vujaskovic Z, Donatucci C, Yin FF. Feasibility study of an intensity-modulated radiation model for the study of erectile dysfunction. J Sex Med 2010; 8:411-8. [PMID: 21143413 DOI: 10.1111/j.1743-6109.2010.02125.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Preclinical studies of radiotherapy (RT) induced erectile dysfunction (ED) have been limited by radiation toxicity when using large fields. AIM To develop a protocol of rat prostate irradiation using techniques mimicking the current clinical standard of intensity modulated radiotherapy (IMRT). MAIN OUTCOME MEASURES Quality assurance (QA) testing of plan accuracy, animal health 9 weeks after RT, and intracavernosal pressure (ICP) measurement on cavernosal nerve stimulation. METHODS Computed tomography-based planning was used to develop a stereotactic radiosurgery (SRS) treatment plan for five young adult male Sprague-Dawley rats. Two treatment planning strategies were utilized to deliver 20 Gy in a single fraction: three-dimensional dynamic conformal arc and intensity-modulated arc (RapidArc). QA testing was performed for each plan type. Treatment was delivered using a NovalisTX (Varian Medical Systems) with high-definition multi-leaf collimators using on-board imaging prior to treatment. Each animal was evaluated for ED 2 months after treatment by nerve stimulation and ICP measurement. RESULTS The mean prostate volume and target volume (5 mm expansion of prostate) for the five animals was 0.36 and 0.66 cm3, respectively. Both conformal and RapidArc plans provided at least 95% coverage of the target volume, with rapid dose fall-off. QA plans demonstrated strong agreement between doses of calculated and delivered plans, although the conformal arc plan was more homogenous in treatment delivery. Treatment was well tolerated by the animals with no toxicity out to 9 weeks. Compared with control animals, significant reduction in ICP/mean arterial pressure, maximum ICP, and ICP area under the curve were noted. CONCLUSION Tightly conformal dynamic arc prostate irradiation is feasible and results in minimal toxicity and measurable changes in erectile function.
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Affiliation(s)
- Bridget F Koontz
- Duke University Medical Center, Department of Radiation Oncology, Durham, NC 27710, USA.
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van der Wielen GJ, Vermeij M, de Jong BWD, Schuit M, Marijnissen J, Kok DJ, van Weerden WM, Incrocci L. Changes in the penile arteries of the rat after fractionated irradiation of the prostate: a pilot study. J Sex Med 2009; 6:1908-13. [PMID: 19453915 DOI: 10.1111/j.1743-6109.2009.01272.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
INTRODUCTION External beam radiotherapy for prostate cancer leads to erectile dysfunction in 36%-43% of patients. The underlying mechanism is largely unknown, although some clinical studies suggest that the arterial supply to the corpora cavernosa is responsible. Two animal experimental studies reported on the effects of a single fraction of prostate irradiation on the penile structures. However, irradiation in multiple fractions is more representative of the actual clinical treatment. AIM The present prospective, controlled study was initiated to investigate the effect of fractionated prostate irradiation on the arteries of the corpora cavernosa. MAIN OUTCOME MEASURES Histological evaluation of the penile tissue in comparison with control rats at 2, 4, and 9 weeks after irradiation. METHODS The prostate of twelve rats was treated with external beam radiation in 5 daily fractions of 7.4 gray. Three control rats were treated with sham irradiation. Prostatic and penile tissue was evaluated for general histology (hematoxylin-eosin). The penile tissue was further evaluated after combined staining for collagen (resorcin fuchsin) and alpha-smooth muscle actin (SMA) (Biogenex). RESULTS The prostate showed adequate irradiation with fibrosis occurring at 9 weeks after irradiation. The corpora cavernosa showed arteries that had developed loss of smooth muscle cells expressing SMA, thickening of the intima, and occlusions. All the control rats maintained normal anatomy. CONCLUSION This is the first animal experimental study that demonstrates changes in the arteries of the corpora cavernosa after fractionated irradiation to the prostatic area. The preliminary data suggests that erectile dysfunction after radiotherapy might be caused by radiation damage to the arterial supply of the corpora cavernosa.
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Affiliation(s)
- Gerard J van der Wielen
- Department of Radiation Oncology, Daniel den Hoed Cancer Center, Erasmus MC, Rotterdam, The Netherlands
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van der Wielen GJ, Mulhall JP, Incrocci L. Erectile dysfunction after radiotherapy for prostate cancer and radiation dose to the penile structures: A critical review. Radiother Oncol 2007; 84:107-13. [PMID: 17707936 DOI: 10.1016/j.radonc.2007.07.018] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 06/18/2007] [Accepted: 07/29/2007] [Indexed: 10/22/2022]
Abstract
Erectile dysfunction (ED) is a common sequela after external beam radiotherapy and brachytherapy for prostate cancer. There are several structures in the vicinity of the prostate that are critical to erectile function and that receive a substantial radiation dose: neurovascular bundles (NVBs), internal pudendal arteries (IPAs), accessory pudendal arteries, corpora cavernosa and the penile bulb. Most reports analyzing the correlation between radiation dose to these structures and radiation-induced ED are limited by the small number of patients analyzed in each study. So far, there is no evidence for a role of the NVBs in radiation-induced ED. There are no reports on the IPAs, based on reduced arterial flow in the penis. Several studies show contradicting results on the corpora cavernosa, which house the erectile tissue required for erection. There are contradicting reports on the penile bulb, although studies with more patients tend not to find any correlation. Sparing of the penile bulb to improve potency-preservation is not sufficiently supported by the current literature. If sparing of the penile bulb is achieved by reducing the margin for the apex, an oncological risk is taken, while it is uncertain whether this will improve potency-preservation.
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Affiliation(s)
- Gerard J van der Wielen
- Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
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