Recent advances in intravesical drug/gene delivery

Advances in preclinical approaches for intravesical therapy of bladder cancer

PURPOSE OF REVIEW

The purpose of this review is to explore new strategies to treat bladder cancer. This article addresses challenges and opportunities in intravesical therapy of bladder cancer.

RECENT FINDINGS

The review examines the latest advances in the development of preclinical approaches for intravesical therapy of bladder cancer. It discusses strategies to improve drug delivery efficiency by using synthesized diverse carriers. Immunotherapy with protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride has been shown to be more effective than intravesical Bacillus Calmette-Guerin. Novel drug delivery systems such the urinary drug-disposing strategy and intravesical nanoparticle formulations improve the drug delivery efficiency while minimizing adverse reactions. Innovative imaging techniques using near-infrared fluorescence probes and multifunctional nano-transformers enable real-time detection and targeted therapy in bladder cancer treatment.

SUMMARY

Treatment of bladder cancer is clinically challenging. However, recent progress in drug delivery technologies shows promise. Optimizing these technologies helps improve patient outcomes, and facilitates clinical translation of different treatment modalities.

Fluorinated Organic Polymers for Cancer Drug Delivery

In the realm of cancer therapy, the spotlight is on nanoscale pharmaceutical delivery systems, especially polymer-based nanoparticles, for their enhanced drug dissolution, extended presence in the bloodstream, and precision targeting achieved via surface engineering. Leveraging the amplified permeation and retention phenomenon, these systems concentrate therapeutic agents within tumor tissues. Nonetheless, the hurdles of systemic toxicity, biological barriers, and compatibility with living systems persist. Fluorinated polymers, distinguished by their chemical idiosyncrasies, are poised for extensive biomedical applications, notably in stabilizing drug metabolism, augmenting lipophilicity, and optimizing bioavailability. Material science heralds the advent of fluorinated polymers that, by integrating fluorine atoms, unveil a suite of drug delivery merits: the hydrophobic traits of fluorinated alkyl chains ward off lipid or protein disruption, the carbon-fluorine bond's stability extends the drug's lifecycle in the system, and a lower alkalinity coupled with a diminished ionic charge bolsters the drug's ability to traverse cellular membranes. This comprehensive review delves into the utilization of fluorinated polymers for oncological pharmacotherapy, elucidating their molecular architecture, synthetic pathways, and functional attributes, alongside an exploration of their empirical strengths and the quandaries they encounter in both experimental and clinical settings.

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.

Ultrasound-assisted intravesical botulinum toxin A delivery attenuates acetic acid-induced bladder hyperactivity in rats

Background: Intradetrusor injection of botulinum toxin A (BTX-A) is an effective treatment for overactive bladder (OAB). However, the occurrence of adverse events associated with BTX-A injection therapy hinders its acceptance among patients and its clinical promotion. Intravesical instillation of BTX-A offers a promising alternative to injection therapy for treating OAB. Nevertheless, due to the presence of the bladder permeability barrier (BPB) and the high molecular weight of BTX-A, direct instillation is unable to penetrate the bladder urothelium. Purpose: This study aims to investigate the safety and feasibility of ultrasound-assisted intravesical delivery of BTX-A and its potential benefits in a rat model of bladder hyperactivity induced by acetic acid instillation. Methods: Hengli BTX-A and microbubbles (MB) were mixed and prepared as a novel complex. The size distribution and zeta potentials of the complex were measured. On day 1, rats' bladders were instilled with 1 mL of saline, BTX-A (20 U in 1 mL), MB, or MB-BTX-A (20 U in 1 mL) complex with or without ultrasound (US) exposure (1 MHz, 1.5 W/cm2, 50% duty cycle, sonication for 10 s with a 10-s pause for a total of 10 min). The instillations were maintained for 30 min. After 7 days, cystometry was performed by filling the bladder with saline and 0.3% acetic acid (AA). Bladders were collected, weighed, and processed for immunoblotting, enzyme-linked immunosorbent assay (ELISA), histologic, and immunofluorescence analyses. Expression and distribution of SNAP-25 and SNAP-23 were assessed using Western blot and immunofluorescence. Calcitonin gene-related peptide (CGRP) in the bladder was detected using ELISA. Results: Intercontraction intervals (ICI) decreased by 72.99%, 76.16%, and 73.96% in rats pretreated with saline, BTX-A, and US + MB, respectively. However, rats treated with US + MB + BTX-A showed a significantly reduced response to AA instillation (57.31% decrease in ICI) without affecting amplitude, baseline pressure, or threshold pressure. Rats treated with US + MB + BTX-A exhibited increased cleavage of SNAP-25 and CGRP expression compared to the control group. Conclusion: Ultrasound-assisted intravesical delivery of BTX-A, with the assistance of MB cavitation, led to cleavage of SNAP-25, inhibition of calcitonin gene-related peptide release from afferent nerve terminals, and amelioration of acetic acid-induced bladder hyperactivity. These results support ultrasound-assisted intravesical delivery as an efficient non-injection method for administering BTX-A.

Recent Advances in Cell Membrane Coated-Nanoparticles as Drug Delivery Systems for Tackling Urological Diseases

Recent studies have revealed the functional roles of cell membrane coated-nanoparticles (CMNPs) in tackling urological diseases, including cancers, inflammation, and acute kidney injury. Cells are a fundamental part of pathology to regulate nearly all urological diseases, and, therefore, naturally derived cell membranes inherit the functional role to enhance the biopharmaceutical performance of their encapsulated nanoparticles on drug delivery. In this review, methods for CMNP synthesis and surface engineering are summarized. The application of different types of CMNPs for tackling urological diseases is updated, including cancer cell membrane, stem cell membrane, immune cell membrane, erythrocytes cell membranes, and extracellular vesicles, and their potential for clinical use is discussed.

Hyaluronan nanoplatelets exert an intrinsic anti-inflammatory activity in a rat model of bladder painful syndrome/interstitial cystitis

Glycosaminoglycan (GAG) replenishment therapy consists of the instillation of GAG solutions directly in the bladder to alleviate Bladder Painful Syndrome/Interstitial Cystitis (BPS/IC). However, several issues were reported with this strategy because the GAG solutions are rapidly eliminated from the bladder by spontaneous voiding, and GAG have low bioadhesive behaviors. Herein, GAG nanomaterials with typical flattened morphology were obtained by a self-assembly process. The formation mechanism of those nanomaterials, denoted as nanoplatelets, involves the interaction of α-cyclodextrin cavity and alkyl chains covalently grafted on the GAG. Three GAG were used in this investigation, hyaluronan (HA), chondroitin sulfate (CS), and heparin (HEP). HA NP showed the best anti-inflammatory activity in an LPS-induced in vitro inflammation model of macrophages. They also exhibited the best therapeutic efficacy in a BPS/IC rat inflammation model. Histological examinations of the bladders revealed that HA NP significantly reduced bladder inflammation and regenerated the bladder mucosa. This investigation could open new perspectives to alleviate BPS/IC through GAG replenishment therapy.

The Progress of Chitosan-Based Nanoparticles for Intravesical Bladder Cancer Treatment

Bladder cancer (BC) is the most frequently occurring cancer of the urinary system, with non-muscle-invasive bladder cancer (NMIBC) accounting for 75-85% of all the bladder cancers. Patients with NMIBC have a good survival rate but are at high risk for tumor recurrence and disease progression. Intravesical instillation of antitumor agents is the standard treatment for NMIBC following transurethral resection of bladder tumors. Chemotherapeutic drugs are broadly employed for bladder cancer treatment, but have limited efficacy due to chemo-resistance and systemic toxicity. Additionally, the periodic voiding of bladder and low permeability of the bladder urothelium impair the retention of drugs, resulting in a weak antitumoral response. Chitosan is a non-toxic and biocompatible polymer which enables better penetration of specific drugs to the deeper cell layers of the bladder as a consequence of temporarily abolishing the barrier function of urothelium, thus offering multifaceted biomedical applications in urinary bladder epithelial. Nowadays, the rapid development of nanoparticles significantly improves the tumor therapy with enhanced drug transport. This review presents an overview on the state of chitosan-based nanoparticles in the field of intravesical bladder cancer treatment.

Recent Progress in Nanomaterial-Based Biosensors and Theranostic Nanomedicine for Bladder Cancer

Bladder cancer (BCa) is one of the most expensive and common malignancies in the urinary system due to its high progression and recurrence rate. Although there are various methods, including cystoscopy, biopsy, and cytology, that have become the standard diagnosis methods for BCa, their intrinsic invasive and inaccurate properties need to be overcome. The novel urine cancer biomarkers are assisted by nanomaterials-based biosensors, such as field-effect transistors (FETs) with high sensitivity and specificity, which may provide solutions to these problems. In addition, nanomaterials can be applied for the advancement of next-generation optical imaging techniques and the contrast agents of conventional techniques; for example, magnetic resonance imaging (MRI) for the diagnosis of BCa. Regarding BCa therapy, nanocarriers, including mucoadhesive nanoparticles and other polymeric nanoparticles, successfully overcome the disadvantages of conventional intravesical instillation and improve the efficacy and safety of intravesical chemotherapy for BCa. Aside from chemotherapy, nanomedicine-based novel therapies, including photodynamic therapy (PDT), photothermal therapy (PTT), chemodynamic therapy (CDT), sonodynamic therapy (SDT), and combination therapy, have afforded us new ways to provide BC therapy and hope, which can be translated into the clinic. In addition, nanomotors and the nanomaterials-based solid tumor disassociation strategy provide new ideas for future research. Here, the advances in BCa diagnosis and therapy mentioned above are reviewed in this paper.

NIR-II-triggered doxorubicin release for orthotopic bladder cancer chemo-photothermal therapy

Intravesical instillation has been widely utilized for bladder cancer treatment in clinic. However, due to the bladder mucosal barrier, its poor penetration efficiency and drug utilization limit the clinical therapeutic effectiveness and result in a high recurrence rate. Therefore, designing an efficient and controllable drug delivery nanoplatform is of great significance for bladder cancer treatment. Non-invasive therapy based on near-infrared-II (NIR-II) photothermal therapy (PTT) conduces to overcome bladder mucosal barrier and enhance drug delivery. Also, the photothermal nanomaterials, Au Hollow Nanorods (AuHNRs), demonstrate strong photothermal properties and drug loading capacity. Herein, a quaternized chitosan N-(2-hydroxyl)propyl-3-trimethyl ammonium chitosan chloride (HTCC)-modified nanocarrier Dox/NH₄HCO₃@AuHNRs-HTCC (DNAH) was designed for controlled drug release and enhanced penetration. The drug loading capacity of DNAH reached 117.20%. Also, the thermal decomposition of NH₄HCO₃ realized NIR-II-triggered gas-driven drug burst release, and the doxorubicin release was 2.79 times higher within 1 h after NIR-II irradiation. Also, the HTCC-modified nanocarriers significantly enhanced the bladder mucosal permeability as well as long-term drug retention, and the penetration efficiency of DNAH increased by 144%. In the orthotopic bladder cancer model, the tumor suppression rate and mouse survival time were significantly improved. DNAH showed potent inhibition of the orthotopic bladder tumor growth owing to the enhanced penetration and drug delivery. This work presents a potential drug delivery nanocarrier, which is promising for optimized bladder mucosal permeability and controlled drug burst release.

Liposome-Encapsulated Botulinum Toxin A in Treatment of Functional Bladder Disorders

Botulinum toxin A (BoNT-A) intravesical injections have been used to treat patients with refractory functional bladder disorders such as overactive bladder (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS), but the risk of adverse events and the need for repeated injections continue to prevent widespread application of this treatment. Liposomes are vesicles that comprise concentric phospholipid layers and an aqueous core; their flexible compositions enable them to adsorb and fuse with cell membranes and to deliver drugs or proteins into cells. Therefore, liposomes have been considered as promising vehicles for the less invasive delivery of BoNT-A. In previous placebo-controlled trials including patients with OAB refractory to medical treatment, it was shown that liposomal BoNT-A could significantly decrease the frequency and urgency of urination. In patients with IC/BPS, it was shown that liposomal BoNT-A could also improve bladder pain, but the therapeutic efficacy was not superior to that of the placebo. As the therapeutic mechanisms of BoNT-A include the decreased expression of nerve growth factors, P2X3 receptors, and vanilloid receptors on C-fibers, liposomal BoNT-A might play a more promising role in the treatment of bladder oversensitivity. This article features the contemporary literature regarding BoNT-A, liposomes, and liposomal BoNT-A treatment for functional bladder disorders and potential clinical applications in the future.

Are Intravesical Aminoglycosides the New Gold Standard in the Management of Refractory Urinary Tract Infection: A Systematic Review of Literature

Background: Antibiotic resistance in urinary pathogens is increasingly common, leading to rising cases of complicated urinary tract infections. Conventional antimicrobial treatment may be insufficient in these cases and broad-spectrum systemic antibiotics contribute to the problem. Intravesical aminoglycoside instillation is an alternative treatment option that delivers localized and high-dose treatment to the source of infection. This study summarizes the existing evidence for the efficacy and safety of this treatment. Methods: A systematic search was conducted of worldwide literature according to PRISMA methodology and Cochrane standards for systematic review. Studies were included if they reported outcome data for the prevention and reduction in urinary tract infections, eradication of antimicrobial-resistant organisms, or change in sensitivities allowing conventional oral antimicrobial treatment after the administration of intravesical aminoglycoside with or without polymyxin therapy. Results: The search identified 826 articles, of which, 19 were included in the final data analysis and narrative synthesis. A successful outcome was identified in 80.7% (n = 289) of patients treated with aminoglycoside alone and 79.5% (n = 163) treated with an aminoglycoside in combination with polymyxin. Discontinuation was noted in 6.2% of patients. An increase in antimicrobial sensitivity was seen in 15.3% (n = 55) and 16.3% (n = 36) in the aminoglycoside and aminoglycoside/polymyxin groups, respectively. Conclusions: Current evidence supports the use of intravesical aminoglycoside instillation as an efficacious and safe treatment for refractory UTIs. Nevertheless, data is limited, and larger volume studies with longer follow-up periods are required.

Nano-Formulation Based Intravesical Drug Delivery Systems: An Overview of Versatile Approaches to Improve Urinary Bladder Diseases

Intravesical drug delivery is a direct drug delivery approach for the treatment of various bladder diseases. The human urinary bladder has distinctive anatomy, making it an effective barrier against any toxic agent seeking entry into the bloodstream. This screening function of the bladder derives from the structure of the urothelium, which acts as a semi-permeable barrier. However, various diseases related to the urinary bladder, such as hyperactive bladder syndrome, interstitial cystitis, cancer, urinary obstructions, or urinary tract infections, can alter the bladder’s natural function. Consequently, the intravesical route of drug delivery can effectively treat such diseases as it offers site-specific drug action with minimum side effects. Intravesical drug delivery is the direct instillation of medicinal drugs into the urinary bladder via a urethral catheter. However, there are some limitations to this method of drug delivery, including the risk of washout of the therapeutic agents with frequent urination. Moreover, due to the limited permeability of the urinary bladder walls, the therapeutic agents are diluted before the process of permeation, and consequently, their efficiency is compromised. Therefore, various types of nanomaterial-based delivery systems are being employed in intravesical drug delivery to enhance the drug penetration and retention at the targeted site. This review article covers the various nanomaterials used for intravesical drug delivery and future aspects of these nanomaterials for intravesical drug delivery.

Functional Nanoparticles for Enhanced Cancer Therapy

Cancer is the leading cause of death in people worldwide. The conventional therapeutic approach is mainly based on chemotherapy, which has a series of side effects. Compared with traditional chemotherapy drugs, nanoparticle-based delivery of anti-cancer drugs possesses a few attractive features. The application of nanotechnology in an interdisciplinary manner in the biomedical field has led to functional nanoparticles achieving much progress in cancer therapy. Nanoparticles have been involved in the diagnosis and targeted and personalized treatment of cancer. For example, different nano-drug strategies, including endogenous and exogenous stimuli-responsive, surface conjugation, and macromolecular encapsulation for nano-drug systems, have successfully prevented tumor procession. The future for functional nanoparticles is bright and promising due to the fast development of nanotechnology. However, there are still some challenges and limitations that need to be considered. Based on the above contents, the present article analyzes the progress in developing functional nanoparticles in cancer therapy. Research gaps and promising strategies for the clinical application are discussed.

Advanced Peptide Nanomedicines for Bladder Cancer Theranostics

Cancer is still a global public health problem. Although remarkable success has been achieved in cancer diagnosis and treatment, the high recurrence and mortality rates remain severely threatening to human lives and health. In recent years, peptide nanomedicines with precise selectivity and high biocompatibility have attracted intense attention in biomedical applications. In particular, there has been a significant increase in the exploration of peptides and their derivatives for malignant tumor therapy and diagnosis. Herein, we review the applications of peptides and their derivatives in the diagnosis and treatment of bladder cancer, providing new insights for the design and development of novel peptide nanomedicines for the treatment of bladder cancer in the future.

Nanotechnology as a tool to advance research and treatment of non-oncologic urogenital diseases

Nanotechnology represents an expanding area of research and innovation in almost every field of science, including Medicine, where nanomaterial-based products have been developed for diagnostic and therapeutic applications. Because of their small, nanoscale size, these materials exhibit unique physical and chemical properties that differ from those of each component when considered in bulk. In Nanomedicine, there is an increasing interest in harnessing these unique properties to engineer nanocarriers for the delivery of therapeutic agents. Nano-based drug delivery platforms have many advantages over conventional drug administration routes as this technology allows for local and transdermal applications of therapeutics that can bypass the first-pass metabolism, improves drug efficacy through encapsulation of hydrophobic drugs, and allows for a sustained and controlled release of encapsulated agents. In Urology, nano-based drug delivery platforms have been extensively investigated and implemented for cancer treatment. However, there is also great potential for use of nanotechnology to treat non-oncologic urogenital diseases. We provide an update on research that is paving the way for clinical translation of nanotechnology in the areas of erectile dysfunction (ED), overactive bladder (OAB), interstitial cystitis/bladder pain syndrome (IC/BPS), and catheter-associated urinary tract infections (CAUTIs). Overall, preclinical and clinical studies have proven the utility of nanomaterials both as vehicles for transdermal and intravesical delivery of therapeutic agents and for urinary catheter formulation with antimicrobial agents to treat non-oncologic urogenital diseases. Although clinical translation will be dependent on overcoming regulatory challenges, it is inevitable before there is universal adoption of this technology to treat non-oncologic urogenital diseases.

Nano-BTA: A New Strategy for Intravesical Delivery of Botulinum Toxin A

Botulinum neurotoxin subtype A (BoNT-A) has been part of the urology treatment arsenal since it was first used in the treatment of detrusor-sphincter dyssynergia more than 30 years ago. BoNT-A has been recommended as an effective treatment for neurogenic detrusor overactivity and overactive bladder. However, direct intradetrusor injection of BoNT-A using cystoscopy after anesthesia may cause hematuria, pain, and infection; these adverse events have motivated urologists to find less invasive and more convenient ways to administer BoNT-A. The development of nanotechnology has led to the advancement of intravesical drug delivery. Using versatile nanocarriers to transport BoNT-A across the impermeable urothelium is a promising therapeutic option. In this review, we discuss the effectiveness and feasibility of liposomes, thermosensitive polymeric hydrogels, and hyaluronan-phosphatidylethanolamine as carriers of BoNT-A for intravesical instillation. To date, these carriers have not reached a similar efficacy as intradetrusor injections in long-term observations. Hopefully, researchers will make a breakthrough with new nanomaterials to develop clinical applications in the future.

Current Researches on Nanodrug Delivery Systems in Bladder Cancer Intravesical Chemotherapy

Bladder cancer is one of the most common malignant tumors in urinary system. Intravesical chemotherapy is a common adjuvant therapy after transurethral resection of bladder tumors. However, it has several disadvantages such as low drug penetration rate, short residence time, unsustainable action and inability to release slowly, thus new drug delivery and new modalities in delivery carriers need to be continuously explored. Nano-drug delivery system is a novel way in treatment for bladder cancer that can increase the absorption rate and prolong the duration of drug, as well as sustain the action by controlling drug release. Currently, nano-drug delivery carriers mainly included liposomes, polymers, and inorganic materials. In this paper, we reveal current researches in nano-drug delivery system in bladder cancer intravesical chemotherapy by describing the applications and defects of liposomes, polymers and inorganic material nanocarriers, and provide a basis for the improvement of intravesical chemotherapy drugs in bladder cancer.

Biodegradable Controlled-Release Device for Localized Chemotherapeutic Treatment of Bladder Cancer

Intravesical therapy for the treatment of superficial urinary bladder tumors is promising. However, it is also challenging, due to bladder contraction and relaxation and drug elimination via urination or dilution by urine production. We developed a biodegradable drug-eluting device positioned in the renal pelvis as an alternative strategy for bladder instillation. The urine drains from the renal pelvis into the ureter, collects the eluted drug, and transports it into the bladder. The combination of the renal pelvis and the bladder creates a two-compartment system. The drug is administered into the depot compartment, the renal pelvis, and is instantly and homogeneously distributed into the central compartment, the bladder. This results in an increase in its residence time and in gradual adsorption into the urothelium. The device is inserted through the ureter, followed by upset bulging after reaching the renal pelvis in order to guarantee fixation, while preventing urinary obstruction. The device is made of electrospun poly(lactic-co-glycolic acid) (PLGA) fibers that encapsulate a chemotherapeutic drug, cisplatin (1.17-2.34% w/w). Experimental studies of the stresses developed during the bulging and simulations of the urine flow interaction with the device demonstrated structural longevity and operational safety of the device. Sustained release of 94% of the device content was demonstrated after 1 week in vitro with a flow rate of 30 mL/h. We believe that the drug-eluted device may offer a significant advantage over existing therapies for treatment of nonmuscle invasive bladder cancer.

Indwelling urinary catheter assembled with lidocaine-loaded polymeric strand for local sustained alleviation of bladder discomfort

Indwelling urinary catheters (IUCs) are used in clinical settings to assist detrusor contraction in hospitalized patients. However, an inserted IUC often causes catheter-related bladder discomfort. To resolve this, we propose an IUC coupled with local, sustained release of an anesthetic drug, lidocaine. For this, a thin strand composed of poly (lactic-co-glycolic acid) and lidocaine was separately prepared as a drug delivery carrier, which was then wound around the surface of the IUC to produce the drug-delivery IUC. Our results revealed that the drug-delivery IUC could exert the pain-relief effects for up to 7 days when placed in the bladder of living rats. Cystometrogram tests indicated that the drug-delivery IUC could significantly relieve bladder discomfort compared with the IUC without lidocaine. Furthermore, the expression of pain-related inflammatory markers, such as nerve growth factor, cyclooxygenase-2, and interleukin-6 in the biopsied bladder tissues was significantly lower when the drug-delivery IUC was used. Therefore, we conclude that an IUC simply assembled with a drug-loaded polymer strand can continuously release lidocaine to allow for the relief of bladder discomfort during the period of IUC insertion.

Microbial contamination and its associations with major ions in shallow groundwater along coastal Tamil Nadu

Microbes in groundwater play a key role in determining the drinking water quality of the water. The study aims to interpret the sources of microbes in groundwater and its relationship to geochemistry. The study was carried out by collecting groundwater samples and analyzed to obtain various cations and anions, where HCO₃^-, Cl^- and NO₃^- found to be higher than permissible limits in few samples. Microbial analysis, like total coliform (TC), total viable counts (TVC), fecal coliforms (FC), Vibrio cholera (V. cholerae) and total Streptococci (T. streptococci) were analyzed, and the observations reveal that most of the samples were found to be above the permissible limits adopted by EU, BIS, WHO and USEPA standards. Correlation analysis shows good correlation between Mg²⁺-HCO₃^-, K⁺-NO₃^-, TVC- V. cholerae and T. streptococci-FC. Major ions like Mg⁺, K⁺, NO₃, Ca²⁺ and PO₄ along with TS and FC were identified to control the geochemical and microbial activities in the region. The magnesium hardness in the groundwater is inferred to influence the TVC and V. cholerae. The mixing of effluents from different sources reflected the association of Cl with TC. Population of microbes T. streptococci and FC was mainly associated with Ca and Cl content in groundwater, depicting the role of electron acceptors and donors. The sources of the microbial population were observed with respect to the land use pattern and the spatial distribution of hydrogeochemical factors in the region. The study inferred that highest microbial activity in the observed in the residential areas, cultivated regions and around the landfill sites due to the leaching of sewage water and fertilizers runoff into groundwater. The concentrations of ions and microbes were found to be above the permissible limits of drinking water quality standards. This may lead to the deterioration in the health of particular coastal region.

Bladder irrigation with povidone-iodine prevent recurrent urinary tract infections in neurogenic bladder patients on clean intermittent catheterization

AIMS

To determine if daily povidone-iodine (PI) bladder irrigation in neurogenic lower urinary tract dysfunction (NLUTD) patients doing clean intermittent catheterization (CIC) can reduce the rate of symptomatic urinary tract infections (UTIs), emergency department (ED) visit for UTIs, and hospitalization for UTIs.

METHODS

We prospectively reviewed the records of patients with NLUTD on CIC who had recurrent symptomatic UTIs and who were placed on daily intravesical instillations of PI. This trial was conducted from January 2014 to January 2020 on 119 patients.

RESULTS

After using daily PI bladder irrigation, the rate of symptomatic UTIs was reduced by 99.2% (incidence rate ratio [IRR]: 0.008, 95% confidence interval [CI]: 0.001-0.059; p < .001), the rate of ED visits was reduced by 99.2%% (IRR: 0.008, 95% CI: 0.001-0.059; p < .001), and the rate of inpatient hospitalizations for UTI was reduced by 99.9% (IRR: 0.0008, 95% CI: 0.0002-0.0035; p < .001). There was also a significant decrease in multidrug resistance in UTI organisms with the use of PI bladder instillation.

CONCLUSIONS

Daily intravesical PI instillation is a well-tolerated approach to prevent UTIs and related ED visits and hospitalizations in NLUTD patients doing CIC.

Development of lipid-like materials for RNA delivery based on intracellular environment-responsive membrane destabilization and spontaneous collapse

Messenger RNA and small interfering RNA are attractive modalities for curing diseases by complementation or knock-down of proteins. For success of these RNAs, a drug delivery system (DDS) is required to control a pharmacokinetics, to enhance cellular uptake, to overcome biological membranes, and to release the cargo into the cytoplasm. Based on past research, developing nanoparticles that are neutrally charged have been the mainstream of their development. Also, the materials are further mounted with pH- and/or reducing environment-responsive units. In this review, we summarize progress made in the molecular design of these materials. We also focus on the importance of the hydrophobic scaffold for tissue/cell targeting, intracellular trafficking, and immune responses. As a practical example, the design concept of the SS-cleavable and pH-activated lipid-like material (ssPalm) and subsequent molecular modification tailored to the RNA-based medical application is discussed.

Current management of refractory overactive bladder

Overactive bladder (OAB) is a common condition affecting one-sixth to one-fifth of the global population. The treatment of refractory OAB remains a challenge for urologists. Current treatment options include the use of combination therapy with antimuscarinic agents and beta-3 adrenoceptor agonists, and treating underlying curable disorders. Intravesical botulinum toxin type A (BoNT-A) injection, percutaneous tibial nerve stimulation, and sacral nerve stimulation are third-line management therapies suggested by the American Urological Association/Society of Urodynamics, Female Pelvic Medicine & Urogenital Reconstruction (AUA/SUFU) guidelines. In rare cases, more invasive surgical interventions can be considered after explaining the benefits and risks to the patients. Augmentation cystoplasty has a high success rate; however, it has also been associated with a high complication rate. In contrast, detrusor myomectomy is an easy procedure, but the treatment outcome remains controversial. Liposome-encapsulated BoNT-A is administered via bladder instillation, and promising results have been obtained in preliminary studies. More therapies are currently being investigated, and transient receptor potential vanilloid 1 antagonists may be new type of medication. Radiofrequency ablation and other targets for neuromodulation have also been studied; however, more evidence is needed to confirm their efficacy.

Enzyme catalysis powered micro/nanomotors for biomedical applications

This review provides insights on enzyme powered motors using fuels present in biological environments for biomedical applications.

Maleimide-functionalised PLGA-PEG nanoparticles as mucoadhesive carriers for intravesical drug delivery

Low permeability of the urinary bladder epithelium, poor retention of the chemotherapeutic agents due to dilution and periodic urine voiding as well as intermittent catheterisations are the major limitations of intravesical drug delivery used in the treatment of bladder cancer. In this work, maleimide-functionalised poly(lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-PEG-Mal) nanoparticles were developed. Their physicochemical characteristics, including morphology, architecture and molecular parameters have been investigated by means of dynamic light scattering, transmission electron microscopy and small-angle neutron scattering techniques. It was established that the size of nanoparticles was dependent on the solvent used in their preparation and molecular weight of PEG, for example, 105 ± 1 nm and 68 ± 1 nm particles were formed from PLGA_20K-PEG_5K in dimethyl sulfoxide and acetone, respectively. PLGA-PEG-Mal nanoparticles were explored as mucoadhesive formulations for drug delivery to the urinary bladder. The retention of fluorescein-loaded nanoparticles on freshly excised lamb bladder mucosa in vitro was evaluated and assessed using a flow-through fluorescence technique and Wash Out₅₀ (WO₅₀) quantitative method. PLGA-PEG-Mal nanoparticles (NPs) exhibited greater retention on urinary bladder mucosa (WO₅₀ = 15 mL) compared to maleimide-free NPs (WO₅₀ = 5 mL). The assessment of the biocompatibility of PEG-Mal using the slug mucosal irritation test revealed that these materials are non-irritant to mucosal surfaces.

Analyzing the effects of instillation volume on intravesical delivery using biphasic solute transport in a deformable geometry

Ailments of the bladder are often treated via intravesical delivery-direct application of therapeutic into the bladder through a catheter. This technique is employed hundreds of thousands of times every year, but protocol development has largely been limited to empirical determination. Furthermore, the numerical analyses of intravesical delivery performed to date have been restricted to static geometries and have not accounted for bladder deformation. This study uses a finite element analysis approach with biphasic solute transport to investigate several parameters pertinent to intravesical delivery including solute concentration, solute transport properties and instillation volume. The volume of instillation was found to have a substantial impact on the exposure of solute to the deeper muscle layers of the bladder, which are typically more difficult to reach. Indeed, increasing the instillation volume from 50-100 ml raised the muscle solute exposure as a percentage of overall bladder exposure from 60-70% with higher levels achieved for larger instillation volumes. Similar increases were not seen for changes in solute concentration or solute transport properties. These results indicate the role that instillation volume may play in targeting particular layers of the bladder during an intravesical delivery.

Fluorinated Polymer Mediated Transmucosal Peptide Delivery for Intravesical Instillation Therapy of Bladder Cancer

Surgical intervention combined with intravesical instillation of chemotherapeutics to clear residual cancer cells after operation is the current standard treatment method for bladder cancer. However, the poor bioavailability of active pharmaceutical ingredients for bladder cancer cells on account of the biological barriers of bladder mucosa, together with significant side effects of currently used intravesical medicine, have limited the clinical outcomes of localized adjuvant therapy for bladder cancer. Aiming at improved intravesical instillation therapy of bladder cancer, a fluorinated polyethylenimine (F-PEI) is employed here for the transmucosal delivery of an active venom peptide, polybia-mastoparan I (MPI), which shows selective antiproliferative effect against various bladder cancer cell lines. Upon simple mixing, MPI and F-PET would coassemble to form stable nanoparticles, which show greatly improved cross-membrane and transmucosal penetration capacities compared with MPI alone or nonfluorinated MPI/PEI nanoparticles. MPI/F-PEI shows higher in vivo tumor growth inhibition efficacy for local treatment of a subcutaneous tumor model. More excitingly, as further demonstrated in an orthotopic bladder cancer model, MPI/F-PEI offers remarkably improved therapeutic effects compared to those achieved by free MPI or the first-line bladder cancer drug mitomycin C. This work presents a new transmucosal delivery carrier particularly promising for intravesical instillation therapy of bladder cancer.

Neomycin-polymyxin or gentamicin bladder instillations decrease symptomatic urinary tract infections in neurogenic bladder patients on clean intermittent catheterization

INTRODUCTION

Recurrent urinary tract infections (UTIs) are common in patients with neurogenic bladder (NGB) performing clean intermittent catheterization (CIC) treated with or without oral antibiotic prophylaxis.

OBJECTIVE

The authors aim to determine if daily neomycin-polymyxin or gentamicin bladder instillations reduce the rate of symptomatic UTIs, the need for oral antibiotic prophylaxis, emergency department (ED) visits for UTI, and inpatient hospitalizations for UTI in patients with NGB on CIC. The authors also aim to investigate resistance patterns in urine microorganisms in patients treated with antibiotic bladder instillations.

STUDY DESIGN

The authors retrospectively reviewed the records of all-age patients cared for in the pediatric urology clinic with NGB on CIC having symptomatic UTIs and on daily intravesical instillations of neomycin-polymyxin or gentamicin between 2013 and 2017. Symptomatic UTIs were defined as a positive urine culture with greater than 10,000 colony forming units/mL associated with one or more of the following patient complaints: cloudy/foul-smelling urine, fevers, chills, increase in bladder spasms, pain, urinary leakage, or physician decision for antibiotic treatment. Multidrug-resistant organisms were resistant to two or more classes of antibiotics.

RESULTS

Fifty-two patients with a median age of 14.5 years and 192 distinct urine cultures were identified. 90.4% and 9.6% of patients received neomycin-polymyxin and gentamicin instillations, respectively. After initiation of intravesical antibiotics, the rate of symptomatic UTIs was reduced by 58% (incidence rate ratio [IRR]: 0.42, 95% confidence interval [CI]: 0.31-0.56; P < 0.001), the rate of ED visits was reduced by 54% (IRR: 0.46, 95% CI: 0.30-0.71; P < 0.001), and the rate of inpatient hospitalizations for UTI was reduced by 39% (IRR: 0.61, 95% CI: 0.37-0.98; P = 0.043). Fewer patients received oral antibiotic prophylaxis after initiation of antibiotic instillations (odds ratio: 0.12, 95% CI: 0.02-0.067; P = 0.016). There was a trend toward a decrease in multidrug resistance and no change in gentamicin resistance in urine microorganisms.

DISCUSSION

This study describes a feasible alternative treatment for patients with NGB on CIC who have persistent UTIs despite oral antibiotic prophylaxis, and for some patients, it may suggest a possibility of discontinuing oral prophylaxis. Limitations include a retrospective design with a small cohort of patients and varying dosages of neomycin-polymyxin.

CONCLUSIONS

Antibiotic bladder instillations appear to decrease frequency of symptomatic UTIs, ED visits for UTI, inpatient hospitalizations for UTI, and the need for oral antibiotic prophylaxis in patients with NGB on CIC. There was no increase in multidrug resistance or gentamicin resistance in UTI organisms with use of intravesical antibiotic instillation.

Targeting 3D Bladder Cancer Spheroids with Urease-Powered Nanomotors

Cancer is one of the main causes of death around the world, lacking efficient clinical treatments that generally present severe side effects. In recent years, various nanosystems have been explored to specifically target tumor tissues, enhancing the efficacy of cancer treatment and minimizing the side effects. In particular, bladder cancer is the ninth most common cancer worldwide and presents a high survival rate but serious recurrence levels, demanding an improvement in the existent therapies. Here, we present urease-powered nanomotors based on mesoporous silica nanoparticles that contain both polyethylene glycol and anti-FGFR3 antibody on their outer surface to target bladder cancer cells in the form of 3D spheroids. The autonomous motion is promoted by urea, which acts as fuel and is inherently present at high concentrations in the bladder. Antibody-modified nanomotors were able to swim in both simulated and real urine, showing a substrate-dependent enhanced diffusion. The internalization efficiency of the antibody-modified nanomotors into the spheroids in the presence of urea was significantly higher compared with antibody-modified passive particles or bare nanomotors. Furthermore, targeted nanomotors resulted in a higher suppression of spheroid proliferation compared with bare nanomotors, which could arise from the local ammonia production and the therapeutic effect of anti-FGFR3. These results hold significant potential for the development of improved targeted cancer therapy and diagnostics using biocompatible nanomotors.

Current Therapeutic Strategies in Clinical Urology

The field of urology encompasses all benign and malignant disorders of the urinary tract and the male genital tract. Urological disorders convey a huge economic and patient quality-of-life burden. Hospital acquired urinary tract infections, in particular, are under scrutiny as a measure of hospital quality. Given the prevalence of these pathologies, there is much progress still to be made in available therapeutic options in order to minimize side effects and provide effective care. Current drug delivery mechanisms in urological malignancy and the benign urological conditions of overactive bladder (OAB), interstitial cystitis/bladder pain syndrome (IC/BPS), and urinary tract infection (UTI) will be reviewed herein. Both systemic and local therapies will be discussed including sustained release formulations, nanocarriers, hydrogels and other reservoir systems, as well as gene and immunotherapy. The primary focus of this review is on agents which have passed the preclinical stages of development.

A bilayer swellable drug-eluting ureteric stent: Localized drug delivery to treat urothelial diseases

A bilayer swellable drug-eluting ureteric stent (BSDEUS) is engineered and implemented, as a sustained drug delivery platform technology that enhances localized drug delivery to the highly impermeable urothelium, for the treatment of urothelial diseases such as strictures and carcinomas. On deployment, the device swells to co-apt with the ureteric wall and ensure drug availability to these tissues. BSDEUS consists of a stent spray-coated with a polymeric drug containing polylactic acid-co-caprolactone (PLC) layer which is overlaid by a swellable polyethylene glycol diacrylate (PEGDA) based hydrogel. In-vitro quantification of released drug demonstrated a tunable time-profile, indicating sustained delivery over 1-month. The PEGDA hydrogel overlayer enhanced drug release and transport into explanted porcine ureteric tissues ex-vivo, under a simulated dynamic fluid flow. A preliminary pilot in-vivo feasibility study, in a porcine model, demonstrated that the swollen hydrogel co-apts with the urothelium and thus enables localized drug delivery to the target tissue section. Kidney functions remained unaffected and device did not result in either hydronephrosis or systemic toxicity. This successful engineering of a bilayer coated stent prototype, demonstrates its feasibility, thus offering a unique solution for drug-based urological therapy.

Local drug delivery in the urinary tract: current challenges and opportunities

Drug delivery is an important consideration in disease treatment. There are many opportunities for novel methods and technologies to hold promising roles in overcoming traditional obstacles. Delivery systems functionalised to boast synergistic antimicrobial effects, specific targeting, and enhanced bioavailability allow for improved therapeutic potential and better patient outcomes. Many of these delivery modalities find clinical practicality in the field of urology, specifically in the treatment of urinary tract infections (UTIs) and offer advantages over conventional methods. The aim of this review article is to discuss the current modalities of treatment for UTIs and the recent technological advancements for optimising drug delivery. We focus on challenges that persist in drug delivery during UTIs including barriers to antimicrobial penetration, drug resistance, biofilm formation and specific targeting limitations. With a discussion on how emerging methods combat these concerns, we present an overview of potential therapies with special emphasis on nanoparticle-based applications.

Use of liposomal doxorubicin for adjuvant chemotherapy of breast cancer in clinical practice

Breast cancer is one of the malignant tumors with the highest morbidity and mortality. It is helpful to reduce the rate of tumor recurrence and metastasis by treating breast cancer with adjuvant chemotherapy, so as to increase the cure rate or survival of patients. In recent years, liposomes have been regarded as a kind of new carrier for targeted drugs. Being effective for enhancing drug efficacy and reducing side effects, they have been widely used for developing anticancer drugs. As a kind of anthracycline with high anticancer activity, doxorubicin can treat or alleviate a variety of malignant tumors effectively when it is used on its own or in combination with other anticancer drugs. Although liposomal doxorubicin has been extensively used in the adjuvant chemotherapy of breast cancer, its exact therapeutic efficacy and side effects have not been definitely proven. Various clinical studies have adopted different combined regimes, dosages, and staging, so their findings differ to certain extent. This paper reviews the clinical application of liposomal doxorubicin in the adjuvant chemotherapy of breast cancer and illustrates therapeutic effects and side effects of pegylated liposomal doxorubicin (PLD) and non-PLD (NPLD) in clinical research, in order to discuss the strategies for applying these drugs in such adjuvant chemotherapy, looking forward to providing references for related research and clinical treatment in terms of dosage, staging, combined regimes, and analysis methods and so on.

Adhesion of thiolated silica nanoparticles to urinary bladder mucosa: Effects of PEGylation, thiol content and particle size

Intravesical drug administration is used to deliver cytotoxic agents through a catheter to treat bladder cancer. One major limitation of this approach is poor retention of the drug in the bladder due to periodic urine voiding. Mucoadhesive dosage forms thus offer significant potential to improve drug retention in the bladder. Here, we investigate thiolated silica nanoparticles retention on porcine bladder mucosa in vitro, quantified through Wash Out50 (WO50) values, defined as the volume of liquid necessary to remove 50% of the adhered particles from a mucosal tissue. Following irrigation with artificial urine solution, the thiolated nanoparticles demonstrate significantly greater retention (WO50 up to 36mL) compared to non-mucoadhesive dextran (WO50 7mL), but have weaker mucoadhesive properties than chitosan (WO50 89mL). PEGylation of thiolated silica reduces their mucoadhesion with WO50 values of 29 and 8mL for particles decorated with 750 and 5000Da PEG, respectively. The retention of thiolated silica nanoparticles is dependent on their thiol group contents and physical dimensions.

A Hydrogel-Based Epirubicin Delivery System for Intravesical Chemotherapy

This study aimed to examine the efficacy of epirubicin-loaded gelatin hydrogel (EPI-H) in the treatment of superficial urothelium carcinoma. Hydrogel was prepared by Schiff base-crosslinking of gelatin with glutaraldehyde. EPI-H exhibited high entrapment efficiency (59.87% ± 0.51%). EPI-H also increased epirubicin accumulation in AY-27 cells when compared with the effect of aqueous solutions of epirubicin (EPI-AQ); respective epirubicin-positive cell counts were 69.0% ± 7.6% and 38.3% ± 5.8%. EPI-H also exhibited greater cytotoxicity against AY-27 cells than that of EPI-AQ; IC50 values were 13.1 ± 1.1 and 7.5 ± 0.3 μg/mL, respectively. Cystometrograms showed that EPI-H reduced peak micturition, threshold pressures, and micturition duration, and that it increased bladder compliance more so than EPI-AQ. EPI-H enhanced epirubicin penetration into basal cells of urothelium in vivo, whereas EPI-AQ did so only to the umbrella cells. EPI-H inhibited tumor growth upon intravesical instillation to tumor-bearing bladder of F344 rats, inducing higher levels of caspase-3 expression than that observed with EPI-AQ treatment; the number of caspase-3 positive cells in treated urothelium carcinoma was 13.9% ± 4.0% (EPI-AQ) and 34.1% ± 1.0%, (EPI-H). EPI-H has value as an improved means to administer epirubicin in intravesical instillation treatments for bladder cancer.

Co-delivery of peptide-modified cisplatin and doxorubicin via mucoadhesive nanocapsules for potential synergistic intravesical chemotherapy of non-muscle-invasive bladder cancer

Synergistic effect against UMUC3 bladder cancer cells was demonstrated via a "two-in-one" combination of doxorubicin (Dox) and peptide-modified cisplatin (Pt-ALy) loaded in positively charged mucoadhesive chitosan-polymethacrylic acid (CM) nanocapsules. The in vitro killing efficacy of the dual drug-loaded nanocapsules (CM-Dox-PtALy) against UMUC3 cells after 4h- and 72h-treatment is much higher (with 5-16 times lower IC50) than either Dox- or Pt-ALy-loaded nanocapsules, resulting in combination indexes of much less than 1 (i.e. obvious synergism) at fractions of affected cells ranging from 0.2 to 0.8. The dose reduction index of Pt-ALy for 72h-treatment is higher than for 4h-treatment, suggesting that Dox in CM-Dox-PtALy played a more significant role in the synergy in the former. The drug-loaded CM nanocapsules are readily taken in by the cells as shown by flow cytometry, confocal laser scanning microscopy and inductively coupled plasma mass spectrometry. Microscopy observations indicate that CM nanocapsules attach strongly on the luminal surface of the bladder with no obvious damage of the urothelium, supporting our objective of prolonging the dwell time of the drug-loaded nanocapsules for intravesical applications. Our study indicates that the mucoadhesive CM-Dox-PtALy nanocapsules have a high drug loading and a sustained release profile, and thus, are promising for synergistic intravesical chemotherapy of non-muscle-invasive bladder cancers.

Novel targeted bladder drug-delivery systems: a review

The objective of pharmaceutics is the development of drugs with increased efficacy and reduced side effects. Prolonged exposure of the diseased tissue to the drug is of crucial importance. Drug-delivery systems (DDSs) have been introduced to control rate, time, and place of release. Drugs can easily reach the bladder through a catheter, while systemically administered agents may undergo extensive metabolism. Continuous urine filling and subsequent washout hinder intravesical drug delivery (IDD). Moreover, the low permeability of the urothelium, also described as the bladder permeability barrier, poses a major challenge in the development of the IDD. DDSs increase bioavailability of drugs, therefore improving therapeutic effect and patient compliance. This review focuses on novel DDSs to treat bladder conditions such as overactive bladder, interstitial cystitis, bladder cancer, and recurrent urinary tract infections. The rationale and strategies for both systemic and local delivery methods are discussed, with emphasis on new formulations of well-known drugs (oxybutynin), nanocarriers, polymeric hydrogels, intravesical devices, encapsulated DDSs, and gene therapy. We give an overview of current and future prospects of DDSs for bladder disorders, including nanotechnology and gene therapy.

Bladder uptake of liposomes after intravesical administration occurs by endocytosis

Liposomes have been used therapeutically and as a local drug delivery system in the bladder. However, the exact mechanism for the uptake of liposomes by bladder cells is unclear. In the present study, we investigated the role of endocytosis in the uptake of liposomes by cultured human UROtsa cells of urothelium and rat bladder. UROtsa cells were incubated in serum-free media with liposomes containing colloidal gold particles for 2 h either at 37°C or at 4°C. Transmission Electron Microscopy (TEM) images of cells incubated at 37°C found endocytic vesicles containing gold inside the cells. In contrast, only extracellular binding was noticed in cells incubated with liposomes at 4°C. Absence of liposome internalization at 4°C indicates the need of energy dependent endocytosis as the primary mechanism of entry of liposomes into the urothelium. Flow cytometry analysis revealed that the uptake of liposomes at 37°C occurs via clathrin mediated endocytosis. Based on these observations, we propose that clathrin mediated endocytosis is the main route of entry for liposomes into the urothelial layer of the bladder and the findings here support the usefulness of liposomes in intravesical drug delivery.

Mucoadhesive polyacrylamide nanogel as a potential hydrophobic drug carrier for intravesical bladder cancer therapy

In this paper, amine-functionalized polyacrylamide nanogels (PAm-NH2) loaded with docetaxel (DTX) were evaluated as a mucoadhesive and sustained intravesical drug delivery (IDD) system for potential bladder cancer therapy. Nanogels have not been applied for such therapy before. The mucoadhesiveness of the PAm-NH2 nanogels, which is a critical factor for IDD application, was investigated using the mucin-particle method and by analyzing the direct attachment of the PAm-NH2 nanogels onto the luminal surface of porcine urinary bladder. DTX, as a model hydrophobic drug, was successfully loaded into hydrophilic PAm-NH2 nanogels with high loading efficiency (>90%), and sustained release of DTX from the nanogels over 9 days in artificial urine was achieved. The nanogels were also taken in by bladder cancer cells in a concentration-dependent manner. The efficiency of the DTX-loaded nanogels in killing UMUC3 and T24 bladder cancer cells was determined to be equivalent to free DTX, and the morphology of the bladder urothelium was not adversely altered by the PAm-NH2 nanogels. These findings indicate that such mucoadhesive nanogels are potentially a promising candidate for intravesical delivery of hydrophobic drugs in bladder cancer therapy.

Preparation and characterization of gelatin-based mucoadhesive nanocomposites as intravesical gene delivery scaffolds

This study aimed to develop optimal gelatin-based mucoadhesive nanocomposites as scaffolds for intravesical gene delivery to the urothelium. Hydrogels were prepared by chemically crosslinking gelatin A or B with glutaraldehyde. Physicochemical and delivery properties including hydration ratio, viscosity, size, yield, thermosensitivity, and enzymatic degradation were studied, and scanning electron microscopy (SEM) was carried out. The optimal hydrogels (H), composed of 15% gelatin A175, displayed an 81.5% yield rate, 87.1% hydration ratio, 42.9 Pa·s viscosity, and 125.8 nm particle size. The crosslinking density of the hydrogels was determined by performing pronase degradation and ninhydrin assays. In vitro lentivirus (LV) release studies involving p24 capsid protein analysis in 293T cells revealed that hydrogels containing lentivirus (H-LV) had a higher cumulative release than that observed for LV alone (3.7-, 2.3-, and 2.3-fold at days 1, 3, and 5, resp.). Lentivirus from lentivector constructed green fluorescent protein (GFP) was then entrapped in hydrogels (H-LV-GFP). H-LV-GFP showed enhanced gene delivery in AY-27 cells in vitro and to rat urothelium by intravesical instillation in vivo. Cystometrogram showed mucoadhesive H-LV reduced peak micturition and threshold pressure and increased bladder compliance. In this study, we successfully developed first optimal gelatin-based mucoadhesive nanocomposites as intravesical gene delivery scaffolds.

Bladder irrigation and urothelium disruption: a reminder apropos of a case of fatal fluid absorption

Background

Irrigation or washouts of the bladder are usually performed in various clinical settings. In the 1980s Elliot and colleagues argued that urothelial damage could occur after washouts and irrigations of the bladder. The exact mechanism underlying urothelial damage has not yet been discovered. To our knowledge, this is the first report of fatal fluid overload and pulmonary edema, due to urothelium disruption occurring during bladder irrigation, approached performing complete histological and immunohistochemical investigation on bladder specimens. The exposed case deserves attention since it demonstrates that, although very rarely, irrigation or washouts of the bladder may have unexpected serious clinical consequences.

Case presentation

An 85 year-old Caucasian man, unable to eat independently and whose fluid intake was controlled, underwent continuous bladder irrigation with a 3-way catheter due to a severe episode of macrohematuria. During the third day of hospitalization, while still undergoing bladder irrigation, he suddenly experienced extreme shortness of breath, breathing difficulties, and cough with frothy sputum. His attending nurse immediately noted that there was no return of the fluid (5 liters) introduced through bladder irrigation. He was treated urgently with hemodialysis. At the beginning of the dialysis treatment, the patient had gained 7.4 kg since the previous measurement (24 hours prior) without any clear explanation. Although a significant weight loss (from 81 to 76 kg) due to the dialysis procedure, the patient died shortly after the final treatment. The autopsy revealed that the brain and the lungs were heavily edematous. Microscopic examination of bladder specimens revealed interstitial and mucosal swelling, and loss of the superficial cell layer. Intermediate and basal urothelial cells were preserved. Altogether the abovementioned findings were suggestive of a diffuse disruption of the urothelium. In conclusion the death of the man was attributed to an acute severe pulmonary edema due to massive fluid absorption.

Conclusion

Our case demonstrates that urothelium disruption may occur during irrigation and washouts of the bladder, also in the absence of other well-known predisposing conditions. Inappropriate use of bladder irrigation should be avoided and a close attention is required of the fluid balance is mandatory when irrigating the bladder.