Corticotropin-releasing hormone perturbations in interstitial cystitis patients: evidence for abnormal sympathetic activity

Autonomic response during bladder hydrodistention reflects the severity of symptoms in patients with bladder pain syndrome/interstitial cystitis

AIMS

To evaluate the correlation between symptom severity of bladder pain syndrome/interstitial cystitis (BPS/IC) and autonomic nervous system activity, we examined autonomic responses during bladder hydrodistention.

METHODS

Medical records were collected from a prospective database for patients who underwent bladder hydrodistention with a fixed protocol from March 2012 to December 2013. A total of 40 patients (16 males, 24 females) were included for the analysis. Hydrodistention was performed under general anesthesia (31 patients), spinal anesthesia (six patients), and both types of anesthesia (three patients) at different times. Twenty-five patients who underwent holmium laser enucleation of the prostate served as controls. Pulse rate (PR), systolic (SBP), and diastolic blood pressure (BP) were measured pre-hydrodistention, during hydrodistention, and after drainage.

RESULTS

The spinal anesthesia and control groups exhibited little change in BP and PR during hydrodistention, while a significant increase was demonstrated in the general anesthesia group (e.g., ΔSBP 4.89 ± 4.80, 10.40 ± 19.03, and 56.26 ± 30.38 mm Hg, respectively, P < 0.001). Under general anesthesia, autonomic response during hydrodistention was more prominent in patients with preoperative visual analogue scale (VAS) pain score ≥7, Hunner's lesion, and glomerulation grade 4. Preoperative maximal cystometric capacity negatively correlated with changes in SBP during hydrodistention (R²  = 0.294, P = 0.009), while VAS score and interstitial cystitis problem index demonstrated a positive correlation with the changes (R²  = 0.208, P = 0.012; R²  = 0.173, P = 0.015).

CONCLUSIONS

Under general anesthesia, exaggerated autonomic responses to bladder hydrodistention were demonstrated in BPS/IC patients, which reflected the severity of symptoms. These results support the hypothesis of altered activity of autonomic system in BPS/IC. Neurourol. Urodynam. 36:677-682, 2017. © 2016 Wiley Periodicals, Inc.

The amygdala central nucleus is required for acute stress-induced bladder hyperalgesia in a rat visceral pain model

Chronic stress has been implicated in the pathogenesis of chronic visceral pain conditions, such as interstitial cystitis (IC), and bouts of acute stress exacerbate clinical urological pain. Studies using animal models have shown that exposure to chronic footshock stress augments reflex responses to urinary bladder distension (UBD) in animal models, however acute effects in animal models are largely unknown, as are the central nervous system mechanisms of stress-related increases in nociception. The amygdala is a salient structure for integration of sensory and cognitive/emotional factors. The present study determined the role of the central nucleus of the amygdala (CeA) in stress-related bladder hypersensitivity. We examined the effects of CeA manipulations (lesions and chemical stimulation) on visceromotor responses (abdominal muscle contractions) to UBD in adult, female Sprague-Dawley rats. We report that acute footshock stress produces bladder hyperalgesia that can be prevented by bilateral CeA lesions, despite no effect of lesions on baseline somatic sensation, as indicated by flinch/jump thresholds to electrical shock. Further, acute glucocorticoid stimulation of the CeA recapitulated stress-induced hyperalgesia. Of note is that CeA lesions, but not chemical stimulation, significantly affected HPA axis activation, as indicated by measurements of circulating corticosterone. Our findings conclusively show that the CeA is necessary for the generation of bladder hyperalgesia in response to acute stress. The CeA may play multiple stress-related roles in nociceptive modulation, i.e., via direct facilitation of the HPA axis during acute stress, or via modulation of other systems that augment acute stress responsiveness.

Brain-derived neurotrophic factor in urinary continence and incontinence

Urinary incontinence adversely affects quality of life and results in an increased financial burden for the elderly. Accumulating evidence suggests a connection between neurotrophins, such as brain-derived neurotrophic factor (BDNF), and lower urinary tract function, particularly with regard to normal physiological function and the pathophysiological mechanisms of stress urinary incontinence (SUI) and bladder pain syndrome/interstitial cystitis (BPS/IC). The interaction between BDNF and glutamate receptors affects both bladder and external urethral sphincter function during micturition. Clinical findings indicate reduced BDNF levels in antepartum and postpartum women, potentially correlating with postpartum SUI. Experiments with animal models demonstrate that BDNF is decreased after simulated childbirth injury, thereby impeding the recovery of injured nerves and the restoration of continence. Treatment with exogenous BDNF facilitates neural recovery and the restoration of continence. Serotonin and noradrenaline reuptake inhibitors, used to treat both depression and SUI, result in enhanced BDNF levels. Understanding the neurophysiological roles of BDNF in maintaining normal urinary function and in the pathogenesis of SUI and BPS/IC could lead to future therapies based on these mechanisms.