Lower Urinary Tract Syndrome (LUTS) affects millions of adults with an array of distressing symptoms, from urgency and pain to incontinence, and can lead to progressive debility, depression and isolation. Although brain control of bladder function is likely dysregulated in many of the millions of patients with lower urinary tract symptoms (LUTS), we know surprisingly little of the precise neural circuits involved and the interplay of neural signaling between brain regions. Advances in neural mapping and availability of disease models (e.g. diabetic, Alzheimer's and interstitial cystitis) in mice, combined with functional imaging and brain stimulation modalities in humans, will make it possible in future to diagnose specific neural deficits in patients with LUTS and apply customized, directed neural therapies. Our current P20 is using modern neuroscience techniques such as optogenetics to map, in fine detail, the neural circuits controlling bladder filling and voiding. To link these mapping studies with functional imaging in humans, we must develop methods to perform functional imaging during cystometrograms (CMGs) in mice. In addition, these methods are needed to examine the role of derangements in brain function in LUTS models in mice. The current proposal is a Resource Development project to create approaches to performing functional MRI (fMRI) using Blood Oxygen Level Dependent (BOLD) MRI to monitor the patterns of brain activation during the filling and voiding cycles of the CMG.
Aim 1 will develop methods to perform BOLD MRI during CMG and analyze the results in anesthetized male and female C57bl/6J mice and males of 2 other mouse strains with void spot and CMG profiles that differ markedly from those of C57bl/6J.
This aim will develop the methods and define the variation of brain activation during CMG phases across mouse diversity.
Aim 2 will extend these methods to conscious mice undergoing CMG, permitting examination of more rostral pathways in regulating and responding to bladder filling and voiding.
Aim 3 will validate elements of the fMRI studies by linking the timing of fMRI activation events during CMGs with calcium fluorescence measurements of activation of the pontine micturition center CRH neurons (PMCCRH) and ventrolateral periaqueductal gray GLUT and GABA neurons (PAGVLGLUT and PAGVLGABA), and obtaining fMRI/CMGs prior to and following direct chemogenetic stimulation of PMCCRH, PAGVLGLUT or PAGVLGABA neurons. We will disseminate these methods on our website, in meetings of project directors, at urological meetings, in publications, and by placing the raw data files onto shared data resources. We will also make these methods available directly to investigators who seek to use them to study mouse LUTS models, either by collaboration, or by teaching them how to perform them in visits to our lab. Development of CMG/BOLD MRI methods in mice will: 1. Augment fine mapping of neural control circuits in mice. 2. Permit direct comparisons between fMRI in mice and in humans. 3. Permit investigators studying LUTS models in mice to interrogate the role of disturbances in brain function in LUTS in mice.
This Resource Development project will develop methods to monitor the sequence of brain activation during bladder filling and voiding in mice undergoing bladder pressure measurements (cystometrograms) using a functional form of magnetic resonance imaging (Blood Oxygen Level Dependent (BOLD-MRI) in anesthetized and conscious mice. !
| Hill, Warren G; Zeidel, Mark L; Bjorling, Dale E et al. (2018) The void spot assay: Recommendations on the use of a simple micturition assay for mice. Am J Physiol Renal Physiol : |
