Modulatory effects of intravesical P2X2/3 purinergic receptor inhibition on lower urinary tract electromyographic properties and voiding function of female rats with moderate or severe spinal cord injury

Urinary ATP may be a biomarker of interstitial cystitis/bladder pain syndrome and its severity

Urinary tract cells respond to bladder distension by releasing adenosine triphosphate (ATP). Patients with interstitial cystitis/bladder pain syndrome (IC/BPS) exhibit elevated urinary ATP levels compared to asymptomatic controls. This study aimed to evaluate the potential of urinary ATP as a non-invasive biomarker for IC/BPS and its correlation with symptom severity. We included 56 patients diagnosed with IC/BPS and 50 asymptomatic controls. Urine samples were collected from both groups. Urinary ATP levels were quantified using the luciferin-luciferase bioluminescence method. The severity of IC/BPS symptoms was assessed using the visual analogue score (VAS), Interstitial Cystitis Symptom Index (ICSI), and Interstitial Cystitis Problem Index (ICPI) from the O'Leary-Sant score. We specifically examined the correlation between symptom scores and urinary ATP levels in IC/BPS patients. Urinary ATP levels were significantly higher in IC/BPS patients compared to the control group (P < 0.0001). There was a significant positive correlation between urinary ATP concentrations and VAS, ICPI, and ICSI scores among IC/BPS patients (P < 0.0001). The threshold value for ATP concentration was set at 56.6 nM, with an area under the receiver operating characteristic (ROC) curve of 0.811 (95% CI 0.730 - 0.892). Our findings indicate that IC/BPS patients excrete elevated amounts of ATP in their urine. This suggests that urinary ATP might serve as a non-invasive biomarker for IC/BPS, with a predictive potential in terms of symptom severity.

Assessing Neurogenic Lower Urinary Tract Dysfunction after Spinal Cord Injury: Animal Models in Preclinical Neuro-Urology Research

Neurogenic bladder dysfunction is a condition that affects both bladder storage and voiding function and remains one of the leading causes of morbidity after spinal cord injury (SCI). The vast majority of individuals with severe SCI develop neurogenic lower urinary tract dysfunction (NLUTD), with symptoms ranging from neurogenic detrusor overactivity, detrusor sphincter dyssynergia, or sphincter underactivity depending on the location and extent of the spinal lesion. Animal models are critical to our fundamental understanding of lower urinary tract function and its dysfunction after SCI, in addition to providing a platform for the assessment of potential therapies. Given the need to develop and evaluate novel assessment tools, as well as therapeutic approaches in animal models of SCI prior to human translation, urodynamics assessment techniques have been implemented to measure NLUTD function in a variety of animals, including rats, mice, cats, dogs and pigs. In this narrative review, we summarize the literature on the use of animal models for cystometry testing in the assessment of SCI-related NLUTD. We also discuss the advantages and disadvantages of various animal models, and opportunities for future research.

Development of a Dynamic Nomogram for Predicting the Probability of Satisfactory Recovery after 6 Months for Cervical Traumatic Spinal Cord Injury

OBJECTIVE

Cervical traumatic spinal cord injury (CTSCI) is a seriously disabling disease that severely affects the physical and mental health of patients and imposes a huge economic burden on patients and their families. Accurate identification of the prognosis of CTSCI patients helps clinicians to design individualized treatment plans for patients. For this purpose, a dynamic nomogram was developed to predict the recovery of CTSCI patients after 6 months.

METHODS

We retrospectively included 475 patients with CTSCI in our institution between March 2013 and January 2022. The outcome variable of the current study was a satisfactory recovery of patients with CTSCI at 6 months. Univariate analyses and univariate logistic regression analyses were used to assess the factors affecting the prognosis of patients with CTSCI. Subsequently, variables (P < 0.05) were included in the multivariate logistic regression analysis to evaluate these factors further. Eventually, a nomogram model was constructed according to these independent risk factors. The concordance index (C-index) and the calibration curve were utilized to assess the model's predictive ability. The discriminating capacity of the prediction model was measured by the receiver operating characteristic (ROC) area under the curve (AUC). One hundred nine patients were randomly selected from 475 patients to serve as the center's internal validation test cohort.

RESULTS

The multivariate logistic regression model further screened out six independent factors that impact the recovery of patients with CTSCI. Including admission to the American Spinal Injury Association Impairment Scale (AIS) grade, the length of high signal in the spinal cord, maximum spinal cord compression (MSCC), spinal segment fractured, admission time, and hormonal therapy within 8 h after injury. A nomogram prediction model was developed based on the six independent factors above. In the training cohort, the AUC of the nomogram that included these predictors was 0.879, while in the test cohort, it was 0.824. The nomogram C-index incorporating these predictors was 0.872 in the training cohort and 0.813 in the test cohort, while the calibration curves for both cohorts also indicated good consistency. Furthermore, this nomogram was converted into a Web-based calculator, which provided individual probabilities of recovery to be generated for individuals with CTSCI after 6 months and displayed in a graphical format.

CONCLUSION

The nomogram, including ASIA grade, the length of high signal in the spinal cord, MSCC, spinal segment fractured, admission time, and hormonal therapy within 8 h after injury, is a promising model to predict the probability of content recovery in patients with CTSCI. This nomogram assists clinicians in stratifying patients with CTSCI, enhancing evidence-based decision-making, and individualizing the most appropriate treatment.

Outcomes of Patients with Cervical Spinal Cord Injury Treated by Surgery and Their Prognostic Factors

Objective

To investigate the outcomes of patients with cervical spinal cord injury treated by surgery and their prognostic factors.

Methods

We retrospectively analyzed 139 patients with cervical spinal cord injury treated by surgery at our hospital, who were admitted between January 2017 and December 2018. Depending on the Barthel index at last follow-up, the patients were divided into the recovery group (n = 60, Barthel index > 45) and the nonrecovery group (n = 79, Barthel index ≤ 45). General information of patients in the two groups was compared. The significant factors were further introduced into the logistic regression model. The poor prognostic factors of cervical spinal cord injury treated by surgery were analyzed, and specific nursing measures were taken.

Results

There were significant differences in the duration of injury before admission, duration of injury before surgery, transportation and protection before admission, spinal canal invasion rate, and hormonal therapy within 8 h after injury between the patients achieving good postoperative recovery and those not (P < 0.05). Logistic regression analysis showed that all the factors above were prognostic factors for cervical spinal cord injury treated surgically.

Conclusion

The duration of injury before admission, duration of injury before surgery, transportation and protection before admission, spinal canal invasion rate, and hormonal therapy within 8 h after injury were prognostic factors of patients with cervical spinal cord injury treated by surgery. The following factors should be considered for favorable outcomes: spinal protection during transportation to hospital, timely hormonal shock therapy to delay injury progression, and timely surgery to relieve pain. The spine is composed of cervical, thoracic, lumbar, sacral, and caudal vertebrae.

Posterior tibial nerve stimulation improves neurogenic bladder in rats with spinal cord injury through transient receptor potential/P2X signaling pathway

BACKGROUND

To study the influences of posterior tibial nerve stimulation (PTNS) on neurogenic bladder and the expression of transient receptor potential (TRP) channels and P2X receptors in rats with spinal cord injury (SCI) and explore the possible mechanism.

METHODS

SCI model was established by modified Allen's method and PTNS was performed. Urodynamic indexes and Haematoxylin and Eosine staining of bladder tissue were used to evaluate the therapeutic effect. The expression of TRP channels and P2X receptors in the bladder and dorsal root ganglia (DRG) was detected by real-time PCR and Western blot.

RESULTS

The low compliance of bladder in treatment group was significantly improved compared with SCI group, and the infiltration of inflammatory cells in bladder tissue was significantly reduced. At the same time, the expression of TRP and P2X in bladder and DRG was partially restored after the treatment of PTNS.

CONCLUSIONS

PTNS is an effective therapy for SCI-induced neurogenic bladder via the TRP/P2X signaling pathway.

Choice of cystometric technique impacts detrusor contractile dynamics in wistar rats

The objective of the current animal study was to investigate factors contributing to the different phases of the cystometrogram (CMG) in order to address disparities in research data reported in the current literature. Three experiments in 20 female Wistar rats were designed to investigate (1) the effects of anesthesia on the contractile pattern of the bladder during micturition; (2) the impact of the physical characteristics of the CMG technique upon the accuracy of intra-vesical pressure recordings; and (3) identification of physiological and methodological factors associated with the emptying and rebound phases during CMG. Variables tested included awake versus urethane-anesthetized conditions, use of a single catheter for both filling and intra-vesical pressure (Pves) recording versus a separate two catheter approach, and comparisons between ureter, bladder dome, and urethral catheter placements. Both awake and anesthetized conditions contributed to variations in the shape and magnitude of the CMG pressure curves. In addition, catheter size, acute incision of the bladder dome for catheter placement, use of the same catheter for filling and Pves recordings, as well as the placement and positioning of the tubing, all contributed to alterations of the physiological properties and characteristic of the various CMG phases, including the frequent occurrence of an artificial rebound during the third phase of micturition. The present results demonstrate how different experimental conditions lead not only to variability in Pves curves, but consistency of the measurements as well, which needs to be accounted for when interpreting CMG outcome data.

Voiding Dysfunction in Old Male Rats Associated With Enlarged Prostate and Irregular Afferent-Triggered Reflex Responses

Purpose

This study was conducted to evaluate the hypothesis that an enlarged prostate in old rats may lead to complications associated with voiding dysfunction involving ionotropic P2X2/3-type purinergic receptors

Methods

Intact animals were divided into male young (MYR; 8–10 weeks old) and male old (MOR; 20 months old) rats. The animals underwent simultaneous detrusor electromyography (EMG) and suprapubic cystometry (CMG) under urethane anesthesia. Immunofluorescence techniques were used to evaluate prostatic autonomic innervation and P2X3R expression in bladder urothelial cells. The functional role of P2X3R was characterized by intramuscular application of AF-353, a selective P2X2/3R antagonist.

Results

The prostate index significantly increased in MOR, suggestive of an enlarged prostate affecting micturition patterns. Significant EMG and CMG differences were found between MYR and MOR. Higher immunoreactivity for P2X2/3R in the urothelial layer and for prostatic neurofilaments was seen in MOR. Systemic inhibition of P2X2/3R had minimal effects on MYR responsiveness, but improved voiding function in MOR with a marked decrease of intravesical pressure and bladder contractile responses.

Conclusions

The data support the hypothesis that an enlarged prostate in MOR may contribute to voiding dysfunction involving activation of P2X2/3R, which enhances a prostate-bladder reflex. This reflex may increase bladder afferent transmission and activation of increased prostate innervation, leading to voiding dysfunction.

P2X3-Containing Receptors as Targets for the Treatment of Chronic Pain

Current therapies for the treatment of chronic pain provide inadequate relief for millions of suffering patients, demonstrating the need for better therapies that will treat pain effectively and improve the quality of patient's lives. Better understanding of the mechanisms that mediate chronic pain is critical for developing drugs with improved clinical outcomes. Adenosine triphosphate (ATP) is a key modulator in nociceptive pathways. Release of ATP from injured tissue or sympathetic efferents has sensitizing effects on sensory neurons in the periphery, and presynaptic vesicular release of ATP from the central terminals can increase glutamate release thereby potentiating downstream central sensitization mechanisms, a condition thought to underlie many chronic pain conditions. The purinergic receptors on sensory nerves primarily responsible for ATP signaling are P2X3 and P2X2/3. Selective knockdown experiments, or inhibition with small molecules, demonstrate P2X3-containing receptors are key targets to modulate nociceptive signals. Preclinical studies have identified that P2X3-containing receptors are critical for sensory transduction for bladder function, and clinical studies have shown promise in treatment for bladder pain and pain associated with osteoarthritis. Further clinical characterization of antagonists to P2X3-containing receptors may lead to improved therapies in the treatment of chronic pain.

The urothelium, the urinary microbioma and men LUTS: a systematic review

INTRODUCTION

The pathophysiology and management of male patients with lower urinary tract symptoms (LUTS) is still a matter of debate. In the past few years, the urothelium and the urinary microbiota represented important areas of research to improve the understanding and management of these patients. Aim of the present review was to summarize the available data on the urothelium and the microbiota related to male LUTS.

EVIDENCE ACQUISITION

A National Center for Biotechnology Information (NCBI) PubMed search for relevant articles published between January 2000 and December 2019 was performed using the medical subjects heading "urothelium," "microbioma," "microbiota," "urobioma," "urobiota," "benign prostatic hyperplasia," "benign prostatic enlargement," "lower urinary tract symptoms," "lower urinary tract dysfunction," "men," "male," "overactive bladder," "receptors." Exclusion criteria included: animal studies and studies on muscarinic and adrenergic pathways.

EVIDENCE SYNTHESIS

The urothelium has been recently evaluated in humans to evaluate new possible markers and pathways. New possible targets for the treatment of male LUTS include the neural growth factor, the cannabinoid, the vanilloid and the ATP pathways. However, studies in humans are still needed to elucidate the exact role of these pathways in the management of male patients with LUTS. The available evidence on the urinary microbioma in male is poor. Standing to the available, urinary microbioma is evident in healthy urine in males. Moreover, the urinary microbioma varies depending on the method of collection, sexually transmitted disease status, inflammation and urinary symptoms. A possible role of probiotics in the management of LUTS in women has been proposed and may have a role in male patients as well.

CONCLUSIONS

The urothelium and the urinary microbiota are still poorly studied in men with LUTS. Most of the evidence and the hypothesis on the relationship between urothelium/urinary microbiota and LUTS comes from animal/in-vitro evidence while clinical trials are lacking. These pathways seem interesting even in LUTS pathogenesis in men but their possible role as a new therapeutic target is still an open debate.

Therapeutic effects and modulatory mechanism of Alpiniae oxyphyllae Fructus in chronic intermittent hypoxia induced enuresis in rats

OBJECTIVE

The objective of this study was to explore the effect of Alpiniae oxyphyllae Fructus (AOF) on a rat model of chronic intermittent hypoxia (CIH)-induced enuresis. Findings of this study may help identify therapeutic targets in children with nocturnal enuresis (NE).

METHODS

Female rats were randomly divided into a control group (saline gavage, 4 weeks of normal air), CIH group (saline gavage, 4 weeks of CIH), and AOF group (AOF gavage, 4 weeks of CIH). The variables measured in this study included water intake, urine output, bladder leak point pressure (BLPP), malondialdehyde (MDA) levels, and superoxide dismutase (SOD) activity. The expression levels of the purinergic P₂X₃ receptor, muscarinic M₃ receptor, and ß₃-adrenergic receptor (ß₃-AR) in the bladder were also measured. The bladder was subjected to haematoxylin and eosin (HE) and Weigert staining, and histological changes were observed under a light microscope to evaluate the morphological changes in the bladder in each group.

RESULTS

Compared with the control group, urine output was increased, and the BLPP was decreased in the CIH group, but AOF administration decreased urine output and increased BLPP. In addition, the serum MDA level increased and the SOD activity decreased in the CIH group compared with the control group. Administration of AOF decreased the MDA level and increased the SOD activity. Additionally, compared with the control group, HE and Weigert staining in the CIH group showed that the bladder detrusor muscle bundles were disordered and loose, some muscle bundles were broken, the content of collagen fibres in the gap was reduced, and the gap was significantly widened. However, following the administration of AOF, the bladder detrusor muscle bundles were neatly arranged, and the content of collagen fibres in the gap was increased. Furthermore, compared with the control group, the purinergic P₂X₃ receptor and muscarinic M₃ receptor were expressed at higher levels, and ß₃-AR was expressed at lower levels in the CIH group, but AOF administration decreased the expression of the purinergic P₂X₃ receptor and muscarinic M₃ receptor and increased the expression of the ß₃-AR.

CONCLUSIONS

AOF improves enuresis by inhibiting oxidative stress and regulating the expression of the purinergic P₂X₃ receptor, muscarinic M₃ receptor, and ß₃ adrenergic receptor.