Javed Mahmood1, Caroline Q Connors2, Allen A Alexander2, Radmila Pavlovic2, Santanu Samanta2, Sandrine Soman2, Hotaka Matsui3, Nikolai A Sopko4, Trinity J Bivalacqua4, Daniel Weinreich5, Cheng-Ying Ho6, John Eley2, Amit Sawant2, Isabel L Jackson2, Zeljko Vujaskovic2. 1. Division of Translational Radiation Sciences, Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland. Electronic address: jmahmood@som.umaryland.edu. 2. Division of Translational Radiation Sciences, Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland. 3. Department of Urology, University of Tokyo, Tokyo, Japan. 4. James Buchanan Brady Urological Institute and Department of Urology, The Johns Hopkins University School of Medicine, Baltimore, Maryland. 5. Department of Pharmacology, University of Maryland School of Medicine, Baltimore, Maryland. 6. Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland.
Abstract
PURPOSE/ OBJECTIVES: Radiation-induced erectile-dysfunction (RiED) is one of the most common side effects of radiation therapy (RT) and significantly reduces the quality of life (QoL) of cancer patients. Approximately 50% of prostate cancer patients experience RiED within 3 to 5 years after completion of RT. A series of vascular, muscular, and neurogenic injuries after prostate RT lead to RiED; however, the precise role of RT-induced neurogenic injury in RiED has not been fully established. The cavernous nerves (CN) are postganglionic parasympathetic nerves located beside the prostate gland that assist in penile erection. This study was designed to investigate the role of CN injury, tissue damage, and altered signaling pathways in an RiED rat model. METHODS AND MATERIALS: Male rats were exposed to a single dose of 25 Gy prostate-confined RT. Erectile function was evaluated by intracavernous pressure (ICP) measurements conducted both 9 and 14 weeks after RT. Neuronal injury was evaluated in the CN using quantitative polymerase chain reaction, conduction studies, transmission electron microscopy, and immunoblotting. Masson trichrome staining was performed to elucidate fibrosis level in penile tissues. RESULTS: There were significant alterations in the ICP (P<.0001) of RT rats versus non-RT rats. TEM analysis showed decreased myelination, increased microvascular damage, and progressive axonal atrophy of the CN fibers after RT. Electrophysiologic analysis showed significant impairment of the CN conduction velocity after RT. RT also significantly increased RhoA/Rho-associated protein kinase 1 (ROCK1) mRNA and protein expression. In addition, penile tissue showed increased apoptosis and fibrosis 14 weeks after RT. CONCLUSIONS: RT-induced CN injury may contribute to RiED; this is therefore a rationale for developing novel therapeutic strategies to mitigate CN and tissue damage. Moreover, further investigation of the RhoA/ROCK pathway's role in mitigating RiED is necessary.
PURPOSE/ OBJECTIVES: Radiation-induced erectile-dysfunction (RiED) is one of the most common side effects of radiation therapy (RT) and significantly reduces the quality of life (QoL) of cancerpatients. Approximately 50% of prostate cancerpatients experience RiED within 3 to 5 years after completion of RT. A series of vascular, muscular, and neurogenic injuries after prostate RT lead to RiED; however, the precise role of RT-induced neurogenic injury in RiED has not been fully established. The cavernous nerves (CN) are postganglionic parasympathetic nerves located beside the prostate gland that assist in penile erection. This study was designed to investigate the role of CN injury, tissue damage, and altered signaling pathways in an RiEDrat model. METHODS AND MATERIALS: Male rats were exposed to a single dose of 25 Gy prostate-confined RT. Erectile function was evaluated by intracavernous pressure (ICP) measurements conducted both 9 and 14 weeks after RT. Neuronal injury was evaluated in the CN using quantitative polymerase chain reaction, conduction studies, transmission electron microscopy, and immunoblotting. Masson trichrome staining was performed to elucidate fibrosis level in penile tissues. RESULTS: There were significant alterations in the ICP (P<.0001) of RT rats versus non-RT rats. TEM analysis showed decreased myelination, increased microvascular damage, and progressive axonal atrophy of the CN fibers after RT. Electrophysiologic analysis showed significant impairment of the CN conduction velocity after RT. RT also significantly increased RhoA/Rho-associated protein kinase 1 (ROCK1) mRNA and protein expression. In addition, penile tissue showed increased apoptosis and fibrosis 14 weeks after RT. CONCLUSIONS: RT-induced CN injury may contribute to RiED; this is therefore a rationale for developing novel therapeutic strategies to mitigate CN and tissue damage. Moreover, further investigation of the RhoA/ROCK pathway's role in mitigating RiED is necessary.
Authors: Marigdalia K Ramirez-Fort; Marc J Rogers; Roberto Santiago; Sean S Mahase; Melissa Mendez; Yi Zheng; Xiang Kong; James A Kashanian; M Junaid Niaz; Shearwood McClelland; Xiaodong Wu; Neil H Bander; Peter Schlegel; John P Mulhall; Christopher S Lange Journal: Rep Pract Oncol Radiother Date: 2020-03-19
Authors: Marc J Rogers; Marigdalia K Ramirez-Fort; James A Kashanian; Seth A Broster; Jaime Matta; Sean S Mahase; Digna V Fort; M Junaid Niaz; Shearwood McClelland; Neil H Bander; Migdalia Fort; Christopher S Lange; Peter Schlegel; John P Mulhall Journal: Rep Pract Oncol Radiother Date: 2020-05-06
Authors: Alexander C Turner; Shelby A Powers; Michael R Odom; Elena S Pak; Kathleen A Ashcraft; Bridget F Koontz; Johanna L Hannan Journal: Neurourol Urodyn Date: 2021-05-20 Impact factor: 2.367