A rat model of intravesical delivery of small interfering RNA for studying urinary carcinoma

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.

Recent advances in imaging and understanding interstitial cystitis

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating condition associated with intense pelvic pain and bladder storage symptoms. Since diagnosis is difficult, prevalence estimates vary with the methodology used. There is also a lack of proven imaging tools and biomarkers to assist in differentiation of IC/BPS from other urinary disorders (overactive bladder, vulvodynia, endometriosis, and prostatitis). Current uncertainty regarding the etiology and pathology of IC/BPS ultimately impacts its timely and successful treatment, as well as hampers future drug development. This review will cover recent developments in imaging methods, such as magnetic resonance imaging, that advance the understanding of IC/BPS and guide drug development.

SiRNA Crosslinked Nanoparticles for the Treatment of Inflammation-induced Liver Injury

RNA interference mediated by small interfering RNA (siRNA) provides a powerful tool for gene regulation, and has a broad potential as a promising therapeutic strategy. However, therapeutics based on siRNA have had limited clinical success due to their undesirable pharmacokinetic properties. This study presents pH-sensitive nanoparticles-based siRNA delivery systems (PNSDS), which are positive-charge-free nanocarriers, composed of siRNA chemically crosslinked with multi-armed poly(ethylene glycol) carriers via acid-labile acetal linkers. The unique siRNA crosslinked structure of PNSDS allows it to have minimal cytotoxicity, high siRNA loading efficiency, and a stimulus-responsive property that enables the selective intracellular release of siRNA in response to pH conditions. This study demonstrates that PNSDS can deliver tumor necrosis factor alpha (TNF-α) siRNA into macrophages and induce the efficient down regulation of the targeted gene in complete cell culture media. Moreover, PNSDS with mannose targeting moieties can selectively accumulate in mice liver, induce specific inhibition of macrophage TNF-α expression in vivo, and consequently protect mice from inflammation-induced liver damages. Therefore, this novel siRNA delivering platform would greatly improve the therapeutic potential of RNAi based therapies.

Optimization of multifunctional chitosan-siRNA nanoparticles for oral delivery applications, targeting TNF-α silencing in rats

Secretion of tumor necrosis factor-α (TNF-α) by macrophages plays a predominant role in the development and progression of various inflammatory diseases. In the current contribution, multifunctional nanoparticles (NPs) containing TNF-α siRNA targeting macrophages via oral administration were developed to knockdown TNF-α expression against acute hepatic injury in rats. Mannose-modified trimethyl chitosan-cysteine (MTC) NPs were prepared by self-assembly method (sa-MTC NPs), ionic gelation and siRNA entrapment method (en-MTC NPs), and ionic gelation and siRNA adsorption method (ad-MTC NPs). Among them, en-MTC NPs demonstrated the best stability against ionic challenges with desired siRNA integrity against nucleases. By targeting normal enterocytes and M cells that express mannose receptors, en-MTC NPs notably promoted intestinal absorption of siRNA in rats. They further facilitated siRNA internalization by rat peritoneal exudate cells (PECs) via lipid-raft involved endocytosis and macropinocytosis, thus inducing effective in vitro TNF-α knockdown. Orally delivered en-MTC NPs at a low siRNA dose of 50 μg/kg inhibited systemic TNF-α production and decreased TNF-α mRNA levels in macrophage-enriched liver, spleen, and lung tissues, which consequently protected rats from acute hepatic injury. Therefore, the en-MTC NPs would provide an effective approach to orally deliver TNF-α siRNA for the anti-inflammatory therapy.

Intravesical liposome and antisense treatment for detrusor overactivity and interstitial cystitis/painful bladder syndrome

Purpose. The following review focuses on the recent advancements in intravesical drug delivery, which brings added benefit to the therapy of detrusor overactivity and interstitial cystitis/painful bladder syndrome (IC/PBS). Results. Intravesical route is a preferred route of administration for restricting the action of extremely potent drugs like DMSO for patients of interstitial cystitis/painful bladder syndrome (IC/PBS) and botulinum toxin for detrusor overactivity. Patients who are either refractory to oral treatment or need to mitigate the adverse effects encountered with conventional routes of administration also chose this route. Its usefulness in some cases can be limited by vehicle (carrier) toxicity or short duration of action. Efforts have been underway to overcome these limitations by developing liposome platform for intravesical delivery of biotechnological products including antisense oligonucleotides. Conclusions. Adoption of forward-thinking approaches can achieve advancements in drug delivery systems targeted to future improvement in pharmacotherapy of bladder diseases. Latest developments in the field of nanotechnology can bring this mode of therapy from second line of treatment for refractory cases to the forefront of disease management.

Formulation approaches to short interfering RNA and MicroRNA: challenges and implications

RNA interference has emerged as a potentially powerful tool in the treatment of genetic and acquired diseases by delivering short interfering RNA (siRNA) or microRNA (miRNA) to target genes, resulting in their silencing. However, many physicochemical and biological barriers have to be overcome to obtain efficient in vivo delivery of siRNA and miRNA molecules to the organ/tissue of interest, thereby enabling their effective clinical therapy. This review discusses the challenges associated with the use of siRNA and miRNA and describes the nonviral delivery strategies used in overcoming these barriers. More specifically, emphasis has been placed on those technologies that have progressed to clinical trials for both local and systemic siRNA and miRNA delivery.