Role of corticotropin-releasing factor on bladder function in rats with psychological stress

Chronic Psychological Stress Disrupts Iron Metabolism and Enhances Hepatic Mitochondrial Function in Mice

To explore the changes in iron metabolism and mitochondrial function exposed to chronic psychological stress, seventy-five male mice aged 5 ~ 6 weeks were randomly sorted into 2 groups: control group and chronic psychological stress group. Mice were conducted by communication box to induce psychological stress for 21 consecutive days. The results showed that chronic psychological stress led to a significant reduction in average daily gain (P < 0.01) and the final weight (P < 0.05). Chronic psychological stress greatly increased plasma and duodenal iron level (P < 0.05), whereas markedly decreased hepatic iron content in mice (P < 0.05). Increasing expression of duodenal DCYTB and FPN (P < 0.05) was observed in mice exposed to chronic psychological stress. Moreover, chronic psychological stress greatly enhanced hepatic TFR1, FTL, and FPN protein expression (P < 0.05) in mice. Additionally, chronic psychological stress enhanced the levels of hepatic NADH, NAD + , ATP, mtDNA content, mtDNA-encoded genes, and the activity of mitochondrial complex I and II (P < 0.05). Taken together, chronic psychological stress impairs growth, disrupts iron metabolism, and enhances hepatic mitochondrial function in mice. These results will provide new insights for understanding the mechanisms of iron metabolism and mitochondrial function during chronic psychological stress.

Stress-induced bladder hypersensitivity: Effect of corticotropin releasing factor receptors assessed by spinal neurophysiology and neurochemistry

Corticotropin releasing factor (CRF) receptors have been implicated in stress-induced hyperalgesia. The present study examined the role of CRF receptors Type 1&2 (CRFR1, CRFR2) in stress-induced bladder hyperalgesia in female rats by quantifying changes in receptor and agonist content following chronic (CFS, 7 daily episodes), acute (AFS, single episode) and control (NFS, no episodes) footshock protocols. ELISAs demonstrated that CFS lead to an increase in spinal thoracolumbar and lumbosacral spinal cord CRFR2 content and a decrease in lumbosacral spinal cord CRFR1 content. Content of the endogenous CRFR2 agonist, urocortin 2, was also increased in lumbosacral spinal cord and bladder tissues of CFS-pretreated rats, but urocortin 3 was decreased. Correlative single unit studies of lumbosacral dorsal horn neurons excited by bladder distension, in anesthetized rats that had undergone CFS, AFS or NFS protocols, used a before-after methodology with administration of a CRFR1 antagonist (antalarmin, 24 μg), CRFR2 antagonist (aSVG30, 12 μg) or normal saline topically to the exposed spinal cord following primary characterization. aSVG30 produced a reduction of neuronal responses evoked by bladder distension in CFS-pretreated rats but no statistically significant effects of aSVG30, antalarmin or vehicle were noted in other groups tested with the exception that antalarmin had an inhibitory effect on spontaneous activity in NFS-pretreated rats. The present findings are consistent with previous experiments using reflex responses to bladder distension as endpoints and further support a role for CRFR2-related mechanisms in stress-induced bladder hypersensitivity. This suggests CRFR2 antagonists may have efficacy in the treatment of bladder pain.

Experimental Evidence of Buyang Huanwu Decoction and Related Modern Preparations (Naoxintong Capsule and Yangyin Tongnao Granule) in Treating Cerebral Ischemia: Intestinal Microorganisms and Transcriptomics in Rats

Background

The traditional Chinese medicines of Buyang Huanwu decoction (BYHW), Naoxintong capsule (NXT), and Yangyin Tongnao granules (YYTN) have excellent effects in preventing and treating cerebrovascular disease and are widely tolerated by patients. However, their effects on middle cerebral artery occlusion (MCAO) remain unknown.

Methods

We evaluated gut microbiota alterations, the brain transcriptome, and nerve cell responses in rats with MCAO.

Results

Our results showed that BYHW, NXT, and YYTN not only effectively improved the damaged state of blood vessels in rats and restored nerve function, but also improved survival. Additional experiments showed that treatment with BYHW, NXT, and YYTN regulated the intestinal microflora. Transcriptome analyses showed that BYHW, NXT, and YYTN modulated the transcriptome of rats with MCAO. The common mechanism of the three prescriptions for the treatment of cerebral ischemia may be related to the intestinal flora regulation of 60S ribosomal protein L18 (Rpl18), eukaryotic translation initiation factor 3 subunit, Ras homolog family member C, G protein subunit gamma 13 (Gng13), and Gng10 genes, among which Rpl18 is the most important. In addition, the three prescriptions had great specificity as anticerebral ischemia targets. Moreover, BYHW, NXT, and YYTN mitigated MCAO-induced hyperactivation of microglia and astrocytes.

Conclusion

This study provides a foundation for further research on the mechanisms and treatment of IS. The results strongly suggest that key gut microbiota can be used to study functional genomics of brain, leading to novel discoveries about key genes involved in important biological processes.

Beyond depression and anxiety; a systematic review about the role of corticotropin-releasing hormone antagonists in diseases of the pelvic and abdominal organs

Evidence for beneficial effects of corticotropin releasing hormone (CRH) antagonists in abdominal and pelvic organs is emerging in preclinical studies. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement a compilation of preclinical studies using CRH receptor antagonists as a treatment for abdominal and pelvic disease was carried out. The Animal Research: Reporting of In Vivo Experiments (ARRIVE) essential 10 guidelines were used to determine quality of the included studies. A total of 40 studies from the last 15 years studying irritable bowel syndrome, inflammatory bowel disease, endometriosis, enteritis, stress impact on gastrointestinal processes and exogenous CRH administration effects were included. Blockage of the CRH receptor 1 was mainly associated with beneficial effects while that of CRH receptor 2 worsened studied effects. However, time of administration, route of administration and the animal model used, all had an impact on the beneficial outcomes. Frequency of drugs administered indicated that astressin-2B, astressin and antalarmin were among the most utilized antagonists. Of concern, studies included were predominantly carried out in male models only, representing a gender discrepancy in preclinical studies compared to the clinical scenario. The ARRIVE score average was 13 with ~60% of the studies failing to randomize or blind the experimental units. Despite the failure to date of the CRH antagonists in moving across the clinical trials pipeline, there is evidence for their beneficial effects beyond mood disorders. Future pre-clinical studies should be tailored towards effectively predicting the clinical scenario, including reduction of bias and randomization.

The Effect of Chronic Psychological Stress on Lower Urinary Tract Function: An Animal Model Perspective

Chronic psychological stress can affect urinary function and exacerbate lower urinary tract (LUT) dysfunction (LUTD), particularly in patients with overactive bladder (OAB) or interstitial cystitis–bladder pain syndrome (IC/BPS). An increasing amount of evidence has highlighted the close relationship between chronic stress and LUTD, while the exact mechanisms underlying it remain unknown. The application of stress-related animal models has provided powerful tools to explore the effect of chronic stress on LUT function. We systematically reviewed recent findings and identified stress-related animal models. Among them, the most widely used was water avoidance stress (WAS), followed by social stress, early life stress (ELS), repeated variable stress (RVS), chronic variable stress (CVS), intermittent restraint stress (IRS), and others. Different types of chronic stress condition the induction of relatively distinguished changes at multiple levels of the micturition pathway. The voiding phenotypes, underlying mechanisms, and possible treatments of stress-induced LUTD were discussed together. The advantages and disadvantages of each stress-related animal model were also summarized to determine the better choice. Through the present review, we hope to expand the current knowledge of the pathophysiological basis of stress-induced LUTD and inspire robust therapies with better outcomes.

Voiding and storage symptoms in depression/anxiety

We here described the frequency and nature of voiding and storage bladder symptoms in depression/anxiety, for which we propose the name "bladder somatic symptom disorder (SSD)" because such symptoms most probably have brain mechanisms. SSD was formerly called as various terms including "somatoform disorder", "medically unexplained physical symptoms", "functional somatic syndrome" and "hysterical neurosis/hysteria". Bladder SSD has the following specific features that are distinguishable from "true" neurologic/organic bladder dysfunction: 1) situation-dependence (close association with life event in some), 2) urodynamically increased bladder sensation/hypersensitivity and 3) absence of neurologic/organic diseases, in addition to 4) other stress symptoms (insomnia, etc.), are key clues to the possibility of bladder SSD. Urodynamics in these patients showed, to a lesser extent, underactive bladder without post-void residual. These findings might reflect the biological changes of the depressive brain; e.g., decreases in serotonin and GABA, and possible increases in CRH. Treatment of bladder SSD can follow that of general depression/anxiety, with the potential addition of anticholinergic or selective beta3 bladder drugs.

Psychological/mental stress-induced effects on urinary function: Possible brain molecules related to psychological/mental stress-induced effects on urinary function

Exposure to psychological/mental stress can affect urinary function, and lead to and exacerbate lower urinary tract dysfunctions. There is increasing evidence showing stress-induced changes not only at phenomenological levels in micturition, but also at multiple levels, lower urinary tract tissues, and peripheral and central nervous systems. The brain plays crucial roles in the regulation of the body's responses to stress; however, it is still unclear how the brain integrates stress-related information to induce changes at these multiple levels, thereby affecting urinary function and lower urinary tract dysfunctions. In this review, we introduce recent urological studies investigating the effects of stress exposure on urinary function and lower urinary tract dysfunctions, and our recent studies exploring "pro-micturition" and "anti-micturition" brain molecules related to stress responses. Based on evidence from these studies, we discuss the future directions of central neurourological research investigating how stress exposure-induced changes at peripheral and central levels affect urinary function and lower urinary tract dysfunctions. Brain molecules that we explored might be entry points into dissecting the stress-mediated process for modulating micturition.

Obsessive-Compulsive Disorders and Functional Urinary Disorders: A Fortuitous Association?

Although psychological factors are known to affect bladder and bowel control, the occurrence of functional urinary disorders in patients with psychiatric disorders has not been well-studied or described. A higher prevalence of functional lower urinary tract disorders have also been reported amongst patients with obsessive-compulsive (OC) disorders. A systematic literature search of PubMed, EMBASE, OVID Medline, PsycINFO, Clinical Trials Register of the Cochrane Collaboration Depression, Anxiety and Neurosis Group (CCDANTR), Clinicaltrials.gov and Google Scholar databases found five observational studies on the topic. Unfortunately, as only one study had a (healthy) control group, a meta-analytic approach was not possible. Overall, patients with OC symptoms appeared to have increased occurrence of functional urinary symptoms, e.g., overactive bladder, increase in urgency, frequency, incontinence and enuresis. This was even more common amongst patients with Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infections (PANDAS) or Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) as opposed to patients with OCD alone. Several biological and behavioural mechanisms and treatment approaches were discussed. However, as the current evidence base was significantly limited and had moderate to serious risk of bias, no strong inferences could be drawn. Further well-designed cohort studies are necessary to better elucidate the observed associations and their management.

Stress and Nasal Allergy: Corticotropin-Releasing Hormone Stimulates Mast Cell Degranulation and Proliferation in Human Nasal Mucosa

Psychological stress exacerbates mast cell (MC)-dependent inflammation, including nasal allergy, but the underlying mechanisms are not thoroughly understood. Because the key stress-mediating neurohormone, corticotropin-releasing hormone (CRH), induces human skin MC degranulation, we hypothesized that CRH may be a key player in stress-aggravated nasal allergy. In the current study, we probed this hypothesis in human nasal mucosa MCs (hM-MCs) in situ using nasal polyp organ culture and tested whether CRH is required for murine M-MC activation by perceived stress in vivo. CRH stimulation significantly increased the number of hM-MCs, stimulated both their degranulation and proliferation ex vivo, and increased stem cell factor (SCF) expression in human nasal mucosa epithelium. CRH also sensitized hM-MCs to further CRH stimulation and promoted a pro-inflammatory hM-MC phenotype. The CRH-induced increase in hM-MCs was mitigated by co-administration of CRH receptor type 1 (CRH-R1)-specific antagonist antalarmin, CRH-R1 small interfering RNA (siRNA), or SCF-neutralizing antibody. In vivo, restraint stress significantly increased the number and degranulation of murine M-MCs compared with sham-stressed mice. This effect was mitigated by intranasal antalarmin. Our data suggest that CRH is a major activator of hM-MC in nasal mucosa, in part via promoting SCF production, and that CRH-R1 antagonists such as antalarmin are promising candidate therapeutics for nasal mucosa neuroinflammation induced by perceived stress.

Voiding Behavior and Efferent Bladder Function Altered in Mice Following Social Defeat but Not Witness Trauma

Psychological stress is associated with bladder dysfunction, however, the local bladder mechanisms affected are not well understood. This study aimed to determine how psychological stress, caused by social defeat or witness trauma, affects voiding behavior and bladder function. Pairs of male C57Bl/6J mice were placed in a custom-made plexiglass chamber with an aggressor ARC(S) mouse for 1 h/day for 10 days. The social defeat mouse was in physical contact with the aggressor, while the witness was physically separated but could observe interactions between its cage-mate and the aggressor. Age matched control pairs were used for comparison. Voiding analysis was conducted periodically over the 10 days. An ex vivo whole bladder preparation was used to assess functional changes after the period of stress. Plasma corticosterone levels were significantly increased by both social defeat and witness trauma stress when compared to unstressed controls. Voiding analysis revealed a significant decrease in voiding frequency in the social defeat group compared to control animals, indicating an altered voiding phenotype. Witness trauma did not alter voiding behavior. Bladder contractile responses to cholinergic stimulation were not significantly altered in either stress group, nor was relaxation to the beta-adrenoceptor agonist isoprenaline. However, nerve evoked contractile responses were significantly increased at all frequencies in bladders from social defeat but not witness trauma mice. Purinergic contractile responses were also significantly enhanced in this group. Social defeat also resulted in increased urothelial acetylcholine release during bladder distension, with no change in ATP release. In conclusion, functional bladder changes are dependent upon stressor type. Enhanced urothelial acetylcholine may desensitize bladder sensory nerves, which, coupled with more efficient voiding contractions due to enhanced nerve-mediated and purinergic detrusor responses, may account for the altered voiding phenotype observed. This study reports a male model of social defeat stress with reduced urinary frequency, with no voiding changes observed in the witness.