Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic, painful condition associated with urinary frequency and urgency for which there are no proven etiologies and no effective treatments. Evidence supports a role for emotional stress in the exacerbation (and possibly development) of generalized pain syndromes such as IC/BPS as well as micturition disorders. Recent analysis of a patient cohort by the MAPP (multidisciplinary approach for the study of pelvic pain) network has confirmed robust differences between individuals with IC/BPS and healthy controls in psychosocial variables and current and lifetime stress. Although the underlying mechanisms mediating the impact of stress on pain are not well understood, recent evidence shows that chronic stress and bladder dysfunction in IC/BPS may be related to autonomic (adrenergic) dysregulation that influences nociceptive signaling. Our preliminary data have provided evidence for stress-induced autonomic modulation of peripheral targets and mitochondrial functions that are likely to play a role in bladder pain. Taken together, our overall hypothesis is that chronic stress induces autonomic and mitochondrial dysregulation and leads to changes in urothelial-neural signaling influencing voiding and pain behavior. Our research teams will use a multidisciplinary approach including molecular biology, measurement of mitochondrial bioenergetics, electrophysiology and imaging to study the effects of psychological stress in our validated rat chronic water avoidance or WAS model.
In Aim #1, we will show that chronic stress increases adrenergic signaling resulting in mitochondrial dysfunction that causes the observed breakdown in the UT barrier. We will measure water and urea permeability and use morphological tools to examine how chronic stress impairs urothelial (UT) regeneration.
In Aim #2, we will show increased sympathetic outflow from chronic stress alters UT memory modulated by altered mitochondrial signaling using functional assays (bioenergetics; Ca+2 imaging; measurement of mitochondrial ROS) and molecular approaches.
In Aim #3 we will show that chronic stress induces afferent hyperexcitability and spinal cord glial cell activation producing symptom equivalents in IC/BPS. We will examine the distribution and activity of bladder afferents and use genetic tools (designer receptors exclusively activated by designer drugs- DREADDs) to block microglial activation and correlate with changes in cellular and functional visceral responses. Of great importance to this project, as part of the ancillary MAPP network we will have a unique opportunity for translational studies. Having access to MAPP resources including patient phenotypes and blood samples will further strengthen the clinical relevance of our findings in the animal model. Findings in our animal model will inform studies in the human and may guide biomarker discovery. In sum, our intriguing preliminary data combined with our extensive expertise and resources places our research team in a unique position to explore mechanisms by which stress-induced autonomic dysregulation can alter normal bladder function and may influence underlying symptoms in IC/BPS.
(RELEVANCE) Physical and emotional stress plays an important role in the exacerbation and possibly development of functional lower urinary tract disorders such as interstitial cystitis/bladder pain syndrome (IC/BPS). Recent evidence shows that chronic stress and bladder dysfunction in IC/BPS may be related to autonomic (adrenergic) dysregulation that influences mitochondrial function and nociceptive signaling. In view of the complex control of the lower urinary tract, including anatomical, neurological and other mechanisms affected by stress- our team of collaborators is in a unique position (by virtue of extensive expertise and resources) to examine mechanisms that may be responsible for the underlying stress-induced autonomic and mitochondrial dysregulation that can result in changes in urothelial and sensory function. These studies (using our water avoidance stress model in rodents) will provide a translational foundation for the development of new approaches targeting stress-resultant pathophysiological processes for the treatment of IC/BPS and other functional pain disorders.