Biodegradable ring-shaped implantable device for intravesical therapy of bladder disorders

Promising Experimental Treatment in Animal Models and Human Studies of Interstitial Cystitis/Bladder Pain Syndrome

Interstitial cystitis/bladder pain Syndrome (IC/BPS) remains a mysterious and intricate urological disorder, presenting significant challenges to healthcare providers. Traditional guidelines for IC/BPS follow a hierarchical model based on symptom severity, advocating for conservative interventions as the initial step, followed by oral pharmacotherapy, intravesical treatments, and, in refractory cases, invasive surgical procedures. This approach embraces a multi-tiered strategy. However, the evolving understanding that IC/BPS represents a paroxysmal chronic pain syndrome, often involving extravesical manifestations and different subtypes, calls for a departure from this uniform approach. This review provides insights into recent advancements in experimental strategies in animal models and human studies. The identified therapeutic approaches fall into four categories: (i) anti-inflammation and anti-angiogenesis using monoclonal antibodies or immune modulation, (ii) regenerative medicine, including stem cell therapy, platelet-rich plasma, and low-intensity extracorporeal shock wave therapy, (iii) drug delivery systems leveraging nanotechnology, and (iv) drug delivery systems assisted by energy devices. Future investigations will require a broader range of animal models, studies on human bladder tissues, and well-designed clinical trials to establish the efficacy and safety of these therapeutic interventions.

Circadian Rhythms Fluctuate the Treatment Effects of Intravesical Treatments on Rat Urinary Frequency Models

Objectives

It is still not clear how the intravesical instillation of drugs affects rat urinary frequency. This study aimed to examine the dynamics of intravesical treatments' treatment effect on rat urinary frequency models by real-time and extended monitoring using a novel continuous urination monitoring system.

Methods

Nine eleven-week-old female Wistar rats were divided into three groups to receive intravesical instillation of 0.1% acetic acid (AA), 1.0% AA, or phosphate-buffered saline (PBS). Thirty minutes later, these drugs were voided, and rats were moved to a continuous urination monitoring system, UM-100. UM-100 monitored rat urination quantitatively and continuously for 24 hours. Rats were then euthanized, and histopathologic examinations using a damage score validated the severity of bladder inflammation. We used nine additional rats to determine the treatment effect of various drugs against the urinary frequency. These rats were also treated with 1.0% AA in the same way and divided into three groups (n = 3 each) to receive intravesical instillation of lidocaine, silver nitrate (AgNO3), or dimethyl sulfoxide (DMSO), respectively. Thirty minutes later, rats were catheterized again and moved to the UM-100, and their voiding was monitored for 24 hours.

Results

Intravesical instillation of AA increased the urinary frequency and decreased the mean voided volume (VV) in a concentration-dependent manner, with statistical significance at a concentration of 1.0% (urinary frequency; p=0.0007, mean VV; p=0.0032, respectively) compared with PBS. Histopathological analysis of these models demonstrated a significantly higher damage score of bladder mucosa in both 0.1% AA and 1.0% AA compared with PBS, with the severity in concordance with the clinical severity of urinary frequency (0.1% AA: p < 0.0001, 1.0% AA: p < 0.0001). Moreover, intravesical instillation of lidocaine, AgNO3, and DMSO decreased the urinary frequency. Continuous monitoring with UM-100 also demonstrated that the treatment effect of these intravesically instilled drugs occurred only at night.

Conclusions

The extended monitoring of rat urination by UM-100 revealed a significant fluctuation in the treatment effect of intravesically instilled drugs between day and night. These findings may help establish novel therapies for urinary frequency.

Progress and challenges in intravesical drug delivery

INTRODUCTION

Intravesical drug delivery (IDD) has gained recognition as a viable approach for treating bladder-related diseases over the years. However, it comes with its set of challenges, including voiding difficulties and limitations in mucosal and epithelial penetration. These challenges lead to drug dilution and clearance, resulting in poor efficacy. Various strategies for drug delivery have been devised to overcome these issues, all aimed at optimizing drug delivery. Nevertheless, there has been minimal translation to clinical settings.

AREAS COVERED

This review provides a detailed description of IDD, including its history, advantages, and challenges. It also explores the physical barriers encountered in IDD, such as voiding, mucosal penetration, and epithelial penetration, and discusses current strategies for overcoming these challenges. Additionally, it offers a comprehensive roadmap for advancing IDD into clinical trials.

EXPERT OPINION

Physical bladder barriers and limitations of conventional treatments result in unsatisfactory efficacy against bladder diseases. Nevertheless, substantial recent efforts in this field have led to significant progress in overcoming these challenges and have raised important attributes for an optimal IDD system. However, there is still a lack of well-defined steps in the workflow to optimize the IDD system for clinical settings, and further research is required to establish more comprehensive in vitro and in vivo models to expedite clinical translation.

Local Drug Delivery in Bladder Cancer: Advances of Nano/Micro/Macro-Scale Drug Delivery Systems

Treatment of bladder cancer remains a critical unmet need and requires advanced approaches, particularly the development of local drug delivery systems. The physiology of the urinary bladder causes the main difficulties in the local treatment of bladder cancer: regular voiding prevents the maintenance of optimal concentration of the instilled drugs, while poor permeability of the urothelium limits the penetration of the drugs into the bladder wall. Therefore, great research efforts have been spent to overcome these hurdles, thereby improving the efficacy of available therapies. The explosive development of nanotechnology, polymer science, and related fields has contributed to the emergence of a number of nanostructured vehicles (nano- and micro-scale) applicable for intravesical drug delivery. Moreover, the engineering approach has facilitated the design of several macro-sized depot systems (centimeter scale) capable of remaining in the bladder for weeks and months. In this article, the main rationales and strategies for improved intravesical delivery are reviewed. Here, we focused on analysis of colloidal nano- and micro-sized drug carriers and indwelling macro-scale devices, which were evaluated for applicability in local therapy for bladder cancer in vivo.

Melanin inspired microcapsules delivering immune metabolites for hepatic fibrosis management

Patients with hepatic fibrosis (HF) have a high risk of developing liver cirrhosis and hepatocellular carcinoma, and there is an urgent need for preventive strategies to block this process. Previous studies have found that disordered inflammation and oxidative damage play important roles in HF progression, suggesting two attractive therapeutic targets. Herein, a new kind of bioinspired microcapsules with a core-shell structure is generated using microfluidics. Polydopamine nanoparticles (PDANPs), a synthetic analogue of natural melanin, are embedded in the polymer shell to provide antioxidative properties for these microcapsules. The aqueous core is used to encapsulate ketone body β-hydroxybutyrate (BHB), an energy metabolite recently known to have regulating effects of cellular signals involved in chronic inflammation. In a HF mouse model, the BHB-encapsulated PDANPs-embedded microcapsules (BHB-PDA-MCs) can not only decrease the severity of inflammatory response, but also the level of oxidative stress. As a result, this combinational strategy is demonstrated to prevent the activation of hepatic stellate cells, the accumulation of extracellular matrix, and the damage of hepatic lobules. These findings indicate that BHB-PDA-MCs can be a promising drug delivery system and have a synergistic effect on HF management.