Potential Orphan Drug Therapy of Intravesical Liposomal Onabotulinumtoxin-A for Ketamine-Induced Cystitis by Mucosal Protection and Anti-inflammation in a Rat Model

Ketamine cystitis following ketamine therapy for treatment-resistant depression - case report

BACKGROUND

Ketamine is a novel and exciting putative antidepressant medication for patients with treatment-resistant depression. A complication commonly seen in frequent and heavy recreational use of ketamine is ulcerative cystitis, which presents with lower urinary tract symptoms (LUTS) and upper renal tract damage and can be seen in over 25% of regular users. Although Ketamine-induced cystitis (KIC) is a recognised complication in recreational use of ketamine, its occurrence in therapeutic use of ketamine in depression has so far not been reported. The exact pathogenesis of KIC is currently unknown, making treatment and prevention advice much more difficult. Early diagnosis of KIC and immediate cessation of ketamine has been shown to improve adverse urinary tract symptoms and prevent further damage.

CASE PRESENTATION

We present a case of a 28-year-old female who was started on ketamine treatment for depression, and who then developed symptoms of KIC, which was confirmed by urine microscopy, culture and analysis.

CONCLUSIONS

To our knowledge, this is the first reported case of KIC in a patient receiving treatment-dose ketamine as part of their antidepressant therapy.

Pathophysiology, clinical presentation, and management of ketamine-induced cystitis

Ketamine is illegally used as a recreational drug in many Asian countries. Long-term ketamine abusers often develop irritable bladder symptoms that gradually develop into more severe urinary frequency and urgency and eventually into a painful ulcerated bladder. These patients typically have reduced functional bladder capacity, increased bladder sensation, detrusor overactivity, severe urgency, urinary incontinence, and bladder contracture. Ketamine metabolites can cause severe inflammation of the urothelium, urothelial barrier deficits, vascular endothelial fibrinoid changes, increased oxidative stress, and bladder wall fibrosis. A decrease in bladder compliance, urinary tract infection, severe bladder pain with a full bladder, and painful micturition are also common symptoms. Finally, with continued abuse of ketamine, hydronephrosis, ureteral stricture, vesicoureteral reflux, and renal failure may develop. Cessation of ketamine is the mainstay of treatment. Lower urinary tract symptoms usually relapse if patients reuse ketamine after stopping. In cases of severe ketamine cystitis, only augmentation enterocystoplasty can relieve bladder pain and restore normal lower urinary tract function. This article reviews the underlying pathophysiology, clinical characteristics, and management of ketamine cystitis.

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.

Molecular Pathophysiology and Potential Therapeutic Strategies of Ketamine-Related Cystitis

Ketamine was first synthesized as a clinical medicine for anesthesia in 1970. It has been used as a recreational drug because of its low cost and hallucination effect in the past decade. Part of ketamine abusers may experience ketamine-related cystitis (KC) and suffer from lower urinary tract symptoms, including urinary frequency, urgency, and severe bladder pain. As the disease progression, a contracted bladder, petechial hemorrhage of the bladder mucosa, and ureteral stricture with hydronephrosis may occur. The pathophysiology of KC is still uncertain, although several hypotheses have been raised. Cessation of ketamine abuse is critical for the management of KC to prevent progressive disease, and effective treatment has not been established. Research has provided some theoretical bases for developing in vitro experiments, animal models, and clinical trials. This review summarized evidence of molecular mechanisms of KC and potential treatment strategies for KC. Further basic and clinical studies will help us better understand the mechanism and develop an effective treatment for KC.

BoNT/A in the Urinary Bladder-More to the Story than Silencing of Cholinergic Nerves

Botulinum neurotoxin (BoNT/A) is an FDA and NICE approved second-line treatment for overactive bladder (OAB) in patients either not responsive or intolerant to anti-cholinergic drugs. BoNT/A acts to weaken muscle contraction by blocking release of the neurotransmitter acetyl choline (ACh) at neuromuscular junctions. However, this biological activity does not easily explain all the observed effects in clinical and non-clinical studies. There are also conflicting reports of expression of the BoNT/A protein receptor, SV2, and intracellular target protein, SNAP-25, in the urothelium and bladder. This review presents the current evidence of BoNT/A’s effect on bladder sensation, potential mechanisms by which it might exert these effects and discusses recent advances in understanding the action of BoNT in bladder tissue.

Rodent models of ketamine-induced cystitis

AIMS

Long-term or recreational use of ketamine affects the urinary system and can result in ketamine-induced cystitis (KIC). Rodent models of KIC are important to study KIC pathophysiology and are paramount to the future development of therapies for this painful condition. This review aims to provide a summary of rodent models of KIC, focusing on disease induction, experimental methods, and pathological features of the model.

METHOD

A literature search was performed using the National Center for Biotechnology Information (NCBI) Pubmed database up to March 2021. 20 articles met the inclusion criteria and were finally selected.

RESULTS

There are considerable variations in the rodent models used for studying KIC in terms of the strain of the animal being used; dose, duration, and route of ketamine administration to induce KIC, and assessment of pathological features.

CONCLUSION

KIC remains difficult to fully recapitulate in humans. Improved characterization of KIC models and the experimental parameters and meticulous discussion on translational limitations are required to improve the translational value of research using rodent models of KIC.

Smaller bladder capacity and stronger bladder contractility in patients with ketamine cystitis are associated with elevated TRPV1 and TRPV4

Stronger contractility and smaller bladder capacity are common symptoms in ketamine cystitis (KC). This study investigates the association between expression levels of transient receptor potential cation channel subfamily V (TRPV) proteins and the clinical characteristics of KC. Bladder tissues were obtained from 24 patients with KC and four asymptomatic control subjects. Video urodynamic parameters were obtained before surgical procedures. The TRPV proteins were investigated by immunoblotting, immunofluorescence staining, and immunohistochemistry. The Pearson test was used to associate the expression levels of TRPV proteins with clinical characteristics of KC. The expression level of TRPV1 and TRPV4 was significantly higher in the severe KC bladders than in mild KC or control bladders. The TRPV1 proteins were localized in all urothelial cell layers, and TRPV4 was located in the basal cells and lamina propria. The expression of TRPV1 was negatively associated with maximal bladder capacity (r = − 0.66, P = 0.01). The expression of TRPV4 was positively associated with the velocity of detrusor pressure rise to the maximum flow rate (r = 0.53, P = 0.01). These observations suggest smaller bladder capacity and stronger contractility in KC are associated with an elevated expression of TRPV1 and TRPV4, respectively.

Local drug delivery systems for inflammatory diseases: Status quo, challenges, and opportunities

Inflammation that is not resolved in due course becomes a chronic disease. The treatment of chronic inflammatory diseases involves a long-term use of anti-inflammatory drugs such as corticosteroids and nonsteroidal anti-inflammatory drugs, often accompanied by dose-dependent side effects. Local drug delivery systems have been widely explored to reduce their off-target side effects and the medication frequency, with several products making to the market or in development over the years. However, numerous challenges remain, and drug delivery technology is underutilized in some applications. This review showcases local drug delivery systems in different inflammatory diseases, including the targets well-known to drug delivery scientists (e.g., joints, eyes, and teeth) and other applications with untapped opportunities (e.g., sinus, bladder, and colon). In each section, we start with a brief description of the disease and commonly used therapy, introduce local drug delivery systems currently on the market or in the development stage, focusing on polymeric systems, and discuss the remaining challenges and opportunities in future product development.

Therapeutic Efficacy of onabotulinumtoxinA Delivered Using Various Approaches in Sensory Bladder Disorder

Cystoscopic onabotulinumtoxinA (onaBoNTA) intradetrusor injection is an efficient and durable modality for treating sensory bladder disorders. However, the inconvenience of using the cystoscopic technique and anesthesia, and the adverse effects of direct needle injection (e.g., haematuria, pain, and infections) have motivated researchers and clinicians to develop diverse injection-free procedures to improve accessibility and prevent adverse effects. However, determining suitable approaches to transfer onaBoNTA, a large molecular and hydrophilic protein, through the impermeable urothelium to reach therapeutic efficacy remains an unmet medical need. Researchers have provided potential solutions in three categories: To disrupt the barrier of the urothelium (e.g., protamine sulfate), to increase the permeability of the urothelium (e.g., electromotive drug delivery and low-energy shock wave), and to create a carrier for transportation (e.g., liposomes, thermosensitive hydrogel, and hyaluronan-phosphatidylethanolamine). Thus far, most of these novel administration techniques have not been well established in their long-term efficacy; therefore, additional clinical trials are warranted to validate the therapeutic efficacy and durability of these techniques. Finally, researchers may make progress with new combinations or biomaterials to change clinical practices in the future.