MP60-12 CHIMERIC BOTULINUM NEUROTOXIN A-B HAS HIGHER NEUROMUSCULAR BLOCKADE POTENCY COMPARED TO BOTULINUM NEUROTOXIN A IN THE MOUSE BLADDER

Abstract

You have accessJournal of UrologyCME1 Apr 2023MP60-12 CHIMERIC BOTULINUM NEUROTOXIN A-B HAS HIGHER NEUROMUSCULAR BLOCKADE POTENCY COMPARED TO BOTULINUM NEUROTOXIN A IN THE MOUSE BLADDER Hatim Thaker, Jie Zhang, Rosalyn Adam, Vivian Cristofaro, Maryrose Sullivan, and Min Dong Hatim ThakerHatim Thaker More articles by this author , Jie ZhangJie Zhang More articles by this author , Rosalyn AdamRosalyn Adam More articles by this author , Vivian CristofaroVivian Cristofaro More articles by this author , Maryrose SullivanMaryrose Sullivan More articles by this author , and Min DongMin Dong More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003318.12AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Neurogenic and idiopathic detrusor overactivity (DO) is currently treated with onabotulinumtoxin A (onaBoNT/A) as third-line therapy. However, BoNT/A requires repeated injections into the bladder and is known to have diminished treatment effect after 5 years. Novel, chimeric toxins may provide an alternative to BoNT/A in the setting of treatment failure. Chimeric BoNT/A-B is a construct that consists of the light chain (catalytic domain) of BoNT/A, paired with a receptor binding domain of BoNT/B. This receptor binding domain binds to synaptotagmin-1, recently shown to be the dominant BoNT receptor in the bladder. Here, we aim to determine the effect of a chimeric BoNT/A-B construct in mouse bladder tissues. METHODS: Gene fragments encoding the light chain and translocation domain of BoNT/A, as well as the receptor binding domain for BoNT/B, were produced via PCR and cloned into a vector to produce chimeric BoNT/A-B. To assess ex vivo smooth muscle response, wild type (WT) mouse bladders were harvested and placed in Kreb's buffer. Each bladder was cut into three longitudinal strips and mounted in tissue chambers at 37 C with continuous bubbled mixture of carbogen. Bladder strips were attached to a force transducer (Figure A) and underwent nerve-evoked contraction studies via electrical field stimulation (EFS; 1-64Hz, 30V 0.5 ms pulse width, 10 sec duration), with the addition of 0.3 or 1 nM BoNT/A-B, to generate a frequency response curve. RESULTS: Ex vivo contraction studies in the presence of 1 nM BoNT/A-B showed a reduction in 80% of nerve-evoked contractions by 100 minutes; BoNT/A had produced the same degree of reduction at only 300 minutes, reflecting the rapid onset of BoNT/A-B. At a lower dose of 0.3 nM, BoNT/A-B reduced nerve-evoked contractions by 40% at 100 minutes; BoNT/A had minimal effect (Figure B). All bladder weights were similar, and data were normalized to the cross-sectional area of the bladder strip. Carbachol dose-response curves served as controls to ensure bladder strips were viable and contractile pre- and post-exposure. CONCLUSIONS: We demonstrate chimeric BoNT/A-B has a faster onset and great potency at lower doses in smooth muscle ex vivo. This novel toxin may provide improved neuromuscular paralysis smooth muscle disorders, such as overactive and neurogenic bladder. Source of Funding: H.T. is supported by the NIH T32 Grant, AUA Urology Care Foundation Research Scholar Award, the SUFU Chemodenervation Grant, and the Office of Faculty Development at Harvard Medical School. M.D. is supported by grants from the NIH and holds the Investigator in the Pathogenesis of Infectious Disease award from the Burroughs Wellcome Fund. M.P.S. received support from the U.S. Department of Veterans Affairs © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e848 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Hatim Thaker More articles by this author Jie Zhang More articles by this author Rosalyn Adam More articles by this author Vivian Cristofaro More articles by this author Maryrose Sullivan More articles by this author Min Dong More articles by this author Expand All Advertisement PDF downloadLoading ...