Manipulating the extracellular matrix: an animal model of the bladder pain syndrome

Restoring the barrier of chronically damaged urothelium using chondroitin sulfate glycosaminoglycan-replenishment therapy

PURPOSE OF REVIEW

This study aims to further understand the physiological mechanism of chondroitin sulfate treatment on the urinary bladder in cases of inflammation, by investigating the effect of chondroitin sulfate therapy on recovery of urothelial barrier in an in-vitro chronic injury model.

RECENT FINDINGS

With inflammatory bladder conditions, the urothelial barrier seems decreased. Glycosaminoglycan (GAG) replacement therapy is supposed to help restore this barrier. Clinical studies on inflammatory bladder conditions are complicated because of the heterogeneous patient population, hence the need for preclinical models.

SUMMARY

In a model using porcine urothelial cells, functional barrier (TEER) and barrier markers were assessed. Chronic urothelial damage was simulated through protamine sulfate instillations with and without subsequent chondroitin sulfate instillations during 3 days. Chondroitin sulfate instillations significantly improved TEER compared to protamine sulfate treatment only (TEER difference 310 Ω.cm 2 , P  < 0.001). This consistent effect over 3 days resulted in a significant higher mean TEER value in the chondroitin sulfate treated group (difference 1855 Ω.cm 2 , P  < 0.001). Enhanced recovery of chondroitin sulfate and other barrier markers was observed.Chondroitin sulfate therapy shows promise in facilitating the recovery of the urothelial barrier in cases of chronic damage. This preclinical study lends support to the use of clinical GAG replenishment therapy for patients with a chronically impaired urothelium.

The urothelial barrier in interstitial cystitis/bladder pain syndrome: its form and function, an overview of preclinical models

PURPOSE OF REVIEW

Investigating bladder pain syndrome/interstitial cystitis (IC/BPS) preclinically is challenging. Various research models have been used to mimic the urothelial barrier closely and replicate the disease. The aim of this review is to discuss preclinical research related to the urothelial barrier in context of IC/BPS.

RECENT FINDINGS

In vivo models mimic IC/BPS mainly with toxic substances in the urine, with protaminesulfate and proteoglycan deglycolysation resembling a temporary impaired barrier as seen in IC/BPS. This temporary increased permeability has also been found in vitro models. Glycosaminoglycan replenishment therapy has been described, in vivo and in vitro, to protect and enhance recover properties of the urothelium. The roles of immune and neurogenic factors in the pathogenesis of IC/BPS remains relatively understudied.

SUMMARY

Preclinical studies provide opportunities to identify the involvement of specific pathologic pathways in IC/BPS. For further research is warranted to elucidate the primary or secondary role of permeability, together with inflammatory and neurogenic causes of the disease.

BCG induced lower urinary tract symptoms during treatment for NMIBC-Mechanisms and management strategies

Non-muscle invasive bladder cancer (NMIBC) accounts for ~70-75% of total bladder cancer tumors and requires effective early intervention to avert progression. The cornerstone of high-risk NMIBC treatment involves trans-urethral resection of the tumor followed by intravesical Bacillus Calmette-Guerin (BCG) immunotherapy. However, BCG therapy is commonly accompanied by significant lower urinary tract symptoms (LUTS) including urinary urgency, urinary frequency, dysuria, and pelvic pain which can undermine treatment adherence and clinical outcomes. Despite this burden, the mechanisms underlying the development of BCG-induced LUTS have yet to be characterized. This review provides a unique perspective on the mechanisms thought to be responsible for the development of BCG-induced LUTS by focussing on the sensory nerves responsible for bladder sensory transduction. This review focuses on how the physiological response to BCG, including inflammation, urothelial permeability, and direct interactions between BCG and sensory nerves could drive bladder afferent sensitization leading to the development of LUTS. Additionally, this review provides an up-to-date summary of the latest clinical data exploring interventions to relieve BCG-induced LUTS, including therapeutic targeting of bladder contractions, inflammation, increased bladder permeability, and direct inhibition of bladder sensory signaling. Addressing the clinical burden of BCG-induced LUTS holds significant potential to enhance patient quality of life, treatment compliance, and overall outcomes in NMIBC management. However, the lack of knowledge on the pathophysiological mechanisms that drive BCG-induced LUTS has limited the development of novel and efficacious therapeutic options. Further research is urgently required to unravel the mechanisms that drive BCG-induced LUTS.

Animal models of interstitial cystitis/bladder pain syndrome

Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS) is a chronic disorder characterized by pelvic and/or bladder pain, along with lower urinary tract symptoms that have a significant impact on an individual's quality of life. The diverse range of symptoms and underlying causes in IC/BPS patients pose a significant challenge for effective disease management and the development of new and effective treatments. To facilitate the development of innovative therapies for IC/BPS, numerous preclinical animal models have been developed, each focusing on distinct pathophysiological components such as localized urothelial permeability or inflammation, psychological stress, autoimmunity, and central sensitization. However, since the precise etiopathophysiology of IC/BPS remains undefined, these animal models have primarily aimed to replicate the key clinical symptoms of bladder hypersensitivity and pain to enhance the translatability of potential therapeutics. Several animal models have now been characterized to mimic the major symptoms of IC/BPS, and significant progress has been made in refining these models to induce chronic symptomatology that more closely resembles the IC/BPS phenotype. Nevertheless, it's important to note that no single model can fully replicate all aspects of the human disease. When selecting an appropriate model for preclinical therapeutic evaluation, consideration must be given to the specific pathology believed to underlie the development of IC/BPS symptoms in a particular patient group, as well as the type and severity of the model, its duration, and the proposed intervention's mechanism of action. Therefore, it is likely that different models will continue to be necessary for preclinical drug development, depending on the unique etiology of IC/BPS being investigated.

Preclinical models of endometriosis and interstitial cystitis/bladder pain syndrome: an Innovative Medicines Initiative-PainCare initiative to improve their value for translational research in pelvic pain

ABSTRACT

Endometriosis (ENDO) and interstitial cystitis/bladder pain syndrome (IC/BPS) are chronic pain conditions for which better treatments are urgently needed. Development of new therapies with proven clinical benefit has been slow. We have conducted a review of existing preclinical in vivo models for ENDO and IC/BPS in rodents, discussed to what extent they replicate the phenotype and pain experience of patients, as well as their relevance for translational research. In 1009 publications detailing ENDO models, 41% used autologous, 26% syngeneic, 18% xenograft, and 11% allogeneic tissue in transplantation models. Intraperitoneal injection of endometrial tissue was the subcategory with the highest construct validity score for translational research. From 1055 IC/BPS publications, most interventions were bladder centric (85%), followed by complex mechanisms (8%) and stress-induced models (7%). Within these categories, the most frequently used models were instillation of irritants (92%), autoimmune (43%), and water avoidance stress (39%), respectively. Notably, although pelvic pain is a hallmark of both conditions and a key endpoint for development of novel therapies, only a small proportion of the studies (models of ENDO: 0.5%-12% and models of IC/BPS: 20%-44%) examined endpoints associated with pain. Moreover, only 2% and 3% of publications using models of ENDO and IC/BPS investigated nonevoked pain endpoints. This analysis highlights the wide variety of models used, limiting reproducibility and translation of results. We recommend refining models so that they better reflect clinical reality, sharing protocols, and using standardized endpoints to improve reproducibility. We are addressing this in our project Innovative Medicines Initiative-PainCare/Translational Research in Pelvic Pain.

Sufentanil postoperative analgesia reduce the increase of T helper 17 (Th17) cells and FoxP3+ regulatory T (Treg) cells in rat hepatocellular carcinoma surgical model: A randomised animal study

Background

Surgery-related pain and opioids might exacerbate immune defenses in immunocompromised cancer patients which might affect postoperativd overall survival. Sufentanil is a good postoperative pain control drug,the present study aimed to figure out whether it effect T cell immunity in rat hepatocellular carcinoma surgical model.

Methods

A rat hepatocellular carcinoma (HCC) models was established by N-nitrosodiethylamine. Forty-eight of them were randomly divided into 3 equal groups: surgery without postoperative analgesia (Group C), surgery with morphine postoperative analgesia (Group M), surgery with sufentanil postoperative analgesia (Group S). Each animal underwent a standard left hepatolobectomy, and intraperitoneally implanted with osmotic minipumps filled with sufentanil, morphine or normal saline according to the different group. The food and water consumptions, body weight changes, locomotor activity and mechanical pain threshold (MPT) were observed. The ratio of CD4⁺/CD8⁺, proportions of Th1, Th2, Th17 and Treg cells in blood were detected using flow cytometry. The liver function and the rats’ survival situation of each group were observed.

Results

The food and water consumption, locomotor activity and MPT of group C declined than those of group S and M on d1, d2, d3 (P < 0.05). The CD4⁺/CD8⁺ ratio and the proportion of Th1 cells were significantly higher while the proportion of Th2, Th17 and Treg cells were significantly lower in group S and group M compared with group C. The rats of group S have higher CD4⁺/CD8⁺ ratio on d3, while lower proportion of Treg cells on d7 compared with group M. The plasma ALT and AST values in group C were significantly higher than that of group S and group M on both d3 and d7. There were not significant differences in mortality rate between 3 groups.

Conclusions

Sufentanil and morphine postoperative analgesia in HCC rats accepted hepatectomy could relieve postoperative pain, promote the recovery of liver function after surgery, alleviate the immunosuppressive effect of pain. Furthermore, Compared to morphine, sufentanil might have a slighter effect on CD4⁺/CD8⁺ ratio and Treg frequencies. Therefore, sufentanil postoperative analgesia is better than morphine in HCC hepatectomy rats.