1. Preclinical Female Model of Urogenital Dysfunction and Pathophysiological Changes After Pelvic Radiation Therapy.
- Author
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Peters B, Powers SA, Burleson LK, Odom MR, Pak ES, Turner AC, Sivanesan N, Koontz BF, and Hannan JL
- Abstract
Introduction Radiation therapy (RT) is the gold standard for many pelvic cancers and improves overall patient survival. However, pelvic RT is associated with increased sexual dysfunction and urinary incontinence. Although the side effects of pelvic RT are well-documented, the pathological mechanisms leading to pelvic organ dysfunction are unknown, and a preclinical model has not been established. This study characterized the impact of pelvic RT at early and late timepoints on female rat bladder, vaginal, and urethral physiology and morphology. Methods Adult female Sprague-Dawley rats were divided into three groups (n = 8/group): (I) Sham, (II) four weeks RT (4wk RT), and (III) nine weeks RT (9wk RT). The RT groups received a single dose of 20 Gy external beam radiation, and experiments were conducted at 4wk and 9wk post-RT. Nerve-mediated vaginal blood flow was measured via laser Doppler. Tissue bath studies assessed vaginal contractility to electric field stimulation (EFS), adrenergic and cholinergic agonists, and relaxation to a nitric oxide donor. Bladder and urethral sphincters were evaluated for cholinergic, caffeine, and EFS-mediated contractility. Quantitative polymerase chain reaction (qPCR) measured gene expression of markers of oxidative stress. Vaginal, bladder, and urethral fibrosis were assessed with Masson's trichrome staining. Results At 4wk post-RT, total vaginal blood flow decreased, and at 9wk post-RT, returned to baseline levels. At 9wk post-RT, vaginal neurogenic and adrenergic-mediated contractile responses increased significantly. Vaginal epithelial thickness decreased post-RT and correlated with an acute rise in vaginal inflammatory gene expression. At 4wk post-RT, bladder neurogenic contractions decreased and remained lowered. Internal urethral contractions increased at 4wk post-RT and returned to Sham levels after 9wk post-RT. Pelvic RT increased external urethral neurogenic contractions, which remained elevated. Conclusion This novel preclinical model provides valuable insights into the temporal pathophysiology of pelvic RT-induced sexual and urinary dysfunction. The establishment of this model is crucial for understanding the underlying mechanisms involved in RT-induced pelvic injury. A reliable, clinically relevant model will allow for the testing of therapeutic strategies to prevent adverse effects with RT in pelvic cancer survivors., Competing Interests: Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: Animal studies were approved by the Institutional Animal Care and Use Committee at East Carolina University and follow the NIH guide for the care and use of laboratory animals. Issued protocol number Q356. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: This research was funded by an ISSWSH Scholars in Women’s Sexual Health Research Grant (SAP), AOA Carolyn L. Kuckein Student Research Fellowship (SAP), and NIH K12 DK100024 (MRO). Financial relationships: Bridget Koontz declare(s) royalties from Demos Publishing. Self; book royalty, unrelated. Bridget Koontz declare(s) support for attending meetings from ASTRO 2023 Annual Meeting. Self; travel expense, unrelated. Bridget Koontz declare(s) personal fees from Nova Southeastern University. Self; consulting, unrelated. Johanna Hannan declare(s) non-financial support from ISSWSH. Chair of Research Grants Committee; unpaid, unrelated. Johanna Hannan declare(s) a grant from National Institutes of Health/NIDDK. NIH R01 DK132425: payment to ECU, unrelated. Johanna Hannan declare(s) non-financial support from Society for Pelvic Research. Social media chair: unpaid, unrelated. Johanna Hannan declare(s) non-financial support from Sexual Medicine Open Access. Associate Editor: unpaid, unrelated. Johanna Hannan declare(s) a grant and non-financial support from Department of Defense. DOD PC220484: payment to ECU, unrelated. Johanna Hannan declare(s) non-financial support from Journal of Sexual Medicine. Editorial Board Member: unpaid, unrelated. Johanna Hannan declare(s) a grant from National Institutes of Health/NIDDK. NIH SBIR R43 DK130750: payment to ECU, unrelated. Bridget Koontz declare(s) non-financial support from NCTN GU Steering Committee. Self; member, unrelated. Shelby Powers declare(s) travel support from Psychoanalytic Center of the Carolinas. Supported travel to APsA Meeting ‘24, unrelated. Shelby Powers declare(s) travel support from North Carolina Society of Addiction Medicine. Travel support to several meetings in 2022-23. Shelby Powers declare(s) non-financial support from American Academy of Addiction Psychiatry. Women in Addiction Psychiatry Special Interest Group Trainee Co-Leader, unrelated. Shelby Powers declare(s) travel support from American Academy of Addiction Psychiatry. Travel award to 2023 annual meeting. Bridget Koontz declare(s) non-financial support from ASTRO. Self; committee member, unrelated. Bridget Koontz declare(s) non-financial support from NRG Oncology. Self; co-chair and PI, unrelated. Bridget Koontz declare(s) personal fees, non-financial support and stock/stock options from Rythera Therapeutics. Consulting, unrelated; stock >$5000, unrelated; Board of Directors, unrelated. Bridget Koontz declare(s) non-financial support from Blue Earth Diagnostics. Self; advisory board, unrelated. Bridget Koontz declare(s) non-financial support from Lantheus. Self; advisory board, unrelated. Johanna Hannan declare(s) non-financial support from Sexual Medicine Society of North America. Committee member for Basic Science and Awards: unpaid, unrelated. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Peters et al.)
- Published
- 2024
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