The fibrosis of ketamine, a noncompetitive N-methyl-d-aspartic acid receptor antagonist dose-dependent change in a ketamine-induced cystitis rat model

Ketamine-Induced Cystitis: A Comprehensive Review of the Urologic Effects of This Psychoactive Drug

Ketamine is a common medical anesthetic and analgesic but is becoming more widely used as a recreational drug. Significant side effects on the urinary tract are associated with frequent recreational ketamine use most notably ketamine-induced cystitis (KIC). Regular ketamine consumption has been shown to increase the risk of cystitis symptoms by 3- to 4-fold, and cessation of ketamine use is usually associated with improvement of symptoms. Common KIC-related problems are urinary pain and discomfort, bladder epithelial barrier damage, reduced bladder storage and increased pressure, ureter stenosis, and kidney failure, all of which significantly impact patients' quality of life. Furthermore, it becomes a vicious cycle when KIC patients attempt to manage their urinary pain with increased ketamine use. The precise pathophysiology of KIC is still unknown but several theories exist, most of which highlight the inflammatory signaling pathways leading to bladder epithelium damage due to presence of ketamine in the urine. Empirical treatment options for KIC are available and consist of ketamine cessation, noninvasive therapies, and surgery, and should be decided upon based on the time course and severity of the disease. Of note, cessation of use is strongly recommended for all KIC patients, and should be supplemented with motivational interviews and psychological and social support. It is crucial for clinicians to be familiar with KIC diagnosis and treatment, and to be prepared to have informed discussions with ketamine-using patients about the potential health consequences of ketamine.

Long-term ketamine administration induces bladder damage and upregulates autophagy-associated proteins in bladder smooth muscle tissue

Long-term ketamine abuse can cause significant lower urinary tract symptoms in humans, termed ketamine-associated cystitis (KC). Here, we established a model of long-term (6 months) ketamine administration in wild-type (C57BL/6) mice. We elucidated the pathological effects of ketamine in the bladder and investigated changes in autophagy-associated protein expression (i.e., LC3, Beclin-1, and P62) and inflammatory cytokines (i.e., IL-6 and IL-1β) in the bladder smooth muscle tissue. Long-term ketamine administration reduced the number of layers in the bladder mucosal epithelial cells (4-5 layers in the saline group vs. 2-3 layers in the ketamine groups), but increased the number of mast cells and collagen fibers. LC3-II/LC3-I, Beclin-1, IL-6, and IL-1β protein expression in the bladder smooth muscle tissues of ketamine-treated mice was significantly increased. The mRNA and protein levels of P62 in the Ket-60 mg/kg group were also significantly increased, but not the Ket-30 mg/kg group. Our results reveal that long-term ketamine administration can cause cystitis-like pathological changes in mice, and the disordered autophagy in the bladder tissue may be involved in the persistent bladder damage following long-term administration of ketamine at 60 mg/kg.

Proteomic analysis exploring the mechanism of bladder fibrosis induced by ketamine using a rat model

Background

Long-term abuse of ketamine can cause irreversible bladder fibrosis, but the mechanism of bladder fibrosis is still under investigation. This study aims to explore the mechanism of bladder fibrosis utilizing proteomic analysis in a rat model.

Methods

After building a rat model, hematoxylin and eosin (HE) staining, Masson’s trichrome staining, and western blotting (WB) of collagen I were used to assess bladder pathology and fibrosis in a rat model. Next, protein expression changes in the rat bladder by proteomic technology were quantitatively detected, and reverse transcription-polymerase chain reaction (RT-PCR) and WB were used to verify the expression of proteins. Bioinformatic techniques and functional analysis were also performed.

Results

Compared to the control group, thinning of the bladder epithelium layer, infiltration of submucosal inflammatory cells, deposition of many collagen fibers, and an elevated expression of collagen I were observed in the experimental group. A total of 3,690 proteins were identified, of which 423 proteins were upregulated, and 304 proteins were down-regulated. Eight out of ten mRNA expressions and acyloxyacyl hydrolase (AOAH), mast cell (MC) protease 1 protein expressions were in line with the proteomic results. Sixty-five differential expression proteins (DEPs) were found to belong to the immune system, and 18 of them were involved in immune diseases, according to KEGG analysis.

Conclusions

We consider that MC protease 1 and platelet activation pathways may play an important role in ketamine-induced bladder fibrosis.

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.

Ketamine-induced urological toxicity: potential mechanisms and translation for adults with mood disorders receiving ketamine treatment

Intravenous (IV) ketamine has been shown to have rapid and robust antidepressant effects in adults with treatment-resistant depression (TRD). Urological toxicity has been observed in chronic ketamine abusers as evidenced by dysuria, urgency, and hematuria. The foregoing observation provides the basis for evaluating whether ketamine-induced urological toxicity (KIUT) is associated with sub-anesthetic doses of ketamine (0.5-1.0 mg/kg) in adults with mood disorders. The overarching objective of this article is to identify potential mechanisms of KIUT which appears to be dose and frequency dependent. Available research indicates that high-frequency ketamine is associated with disruption of the urothelial barrier as well as direct ketamine toxicity (i.e., decreased expression of junction proteins) in KIUT of the bladder. Chronic and high-frequency ketamine use is also associated with bladder inflammation mediated via neurogenic and IgE inflammation. Other non-mutually exclusive causes are nerve hyperplasia, hypersensitivity, cell apoptosis, microvascular damage, and overexpression of carcinogenic genes. Notwithstanding the evidence of KIUT in ketamine abusers, there is no evidence that ketamine and/or esketamine treatment in adults with mood disorders is associated with KIUT. However, all patients receiving ketamine/esketamine for mood disorder treatment should be queried about genitourinary symptoms during acute and, where applicable, maintenance dosing.

Is medicinal ketamine associated with urinary dysfunction issues? Assessment of both the European Medicines Agency (EMA) and the UK Yellow Card Scheme pharmacovigilance database-related reports

OBJECTIVE

A range of ketamine-induced uropathy (KIU) issues have been typically described in ketamine misusers. Conversely, more knowledge is needed in terms of medicinal ketamine-related urological disturbances, since ketamine prescribing is being increasingly considered for a range of medical and psychopathological conditions.

METHODS

To assess medicinal KIU issues, we aimed at analyzing both the 2005-2017 European Medicines Agency (EMA) and the 2006-2018 UK Yellow Card Scheme (YCS) pharmacovigilance databases.

RESULTS

A total number (eg, all categories) of 11 632 EMA ketamine-related adverse drug reaction (ADR) reports were here identified. Out of these, some 9971 ADRs (eg, 85.7% of the total) were judged as "suspect" and were here analyzed. Some 1758 ADRs (17.7% of 9971, corresponding to 194 individual patients) referred to urological issues, relating to either kidney/ureter (922 ADRs) or bladder/urethra (837 ADRs). Ketamine was the sole drug administered in 156/194 (80.4%) cases/patients. Although most cases occurred in the 1 month-1 year time frame following the start of ketamine prescribing, in 30 cases the ADR occurred within 48 hours. Most ADR-related cases resolved, although both sequelae (18 cases) and fatalities (79/1758; 4.5%) were recorded. Overall, YCS data were consistent with EMA findings, with some 50/217 (23%) ADRs referring to renal/urinary disorders.

CONCLUSIONS

Current data may only represent a gross underestimate of the KIU real prevalence issues. It is here suggested that chronic treatment involving higher doses/repeated exposure to ketamine be restricted to the context of controlled trials or clinical audits.

Aldh2 gene reduces oxidative stress in the bladder by regulating the NF-κB pathway in a mouse model of ketamine-induced cystitis

Aldehyde dehydrogenase 2 (aldh2) serves an important role in the development of organ injury. Therefore, the present study investigated the effects of aldh2 on the oxidative stress response in a mouse model of ketamine-induced cystitis (KIC). A total of 60 8-week-old male Institute of Cancer Research wild-type (WT) mice and 45 aldh2 knock-out (KO) mice were randomized to receive low-dose ketamine (30 mg/kg), high-dose ketamine (60 mg/kg) or normal saline (controls). At 4, 8 and 12 weeks post-injection, bladder tissues were harvested and used to investigate the protective mechanisms of aldh2 on bladder function. The results demonstrated that aldh2 KO mice exhibited significant weight loss following chronic ketamine injection compared with that in WT mice. Furthermore, ketamine treatment increased the urination rate (P<0.05), pathological score (P<0.05), levels of the oxidative stress product malondialdehyde (P<0.05) in addition to reducing the expression of the anti-oxidative stress enzyme superoxide dismutase (P<0.05) and glutathione-SH (P<0.05). Oxidative stress in aldh2 KO mice was also found to significantly enhance the expression of proteins associated with the NF-κB signaling pathway, which promoted the expression of inducible nitric oxide synthase (P<0.05) and cyclooxygenase-2 (P<0.05) further. Finally, aldh2 KO mice demonstrated higher severity of fibrosis in the submucosal and muscular layers of the bladder. In conclusion, the present study suggests that aldh2 serves a protective role in preventing inflammation and fibrosis in KIC.

Current and Future Directions of Stem Cell Therapy for Bladder Dysfunction

Stem cells are capable of self-renewal and differentiation into a range of cell types and promote the release of chemokines and progenitor cells necessary for tissue regeneration. Mesenchymal stem cells are multipotent progenitor cells with enhanced proliferation and differentiation capabilities and less tumorigenicity than conventional adult stem cells; these cells are also easier to acquire. Bladder dysfunction is often chronic in nature with limited treatment modalities due to its undetermined pathophysiology. Most treatments focus on symptom alleviation rather than pathognomonic changes repair. The potential of stem cell therapy for bladder dysfunction has been reported in preclinical models for stress urinary incontinence, overactive bladder, detrusor underactivity, and interstitial cystitis/bladder pain syndrome. Despite these findings, however, stem cell therapy is not yet available for clinical use. Only one pilot study on detrusor underactivity and a handful of clinical trials on stress urinary incontinence have reported the effects of stem cell treatment. This limitation may be due to stem cell function loss following ex vivo expansion, poor in vivo engraftment or survival after transplantation, or a lack of understanding of the precise mechanisms of action underlying therapeutic outcomes and in vivo behavior of stem cells administered to target organs. Efficacy comparisons with existing treatment modalities are also needed for the successful clinical application of stem cell therapies. This review describes the current status of stem cell research on treating bladder dysfunction and suggests future directions to facilitate clinical applications of this promising treatment modality, particularly for bladder dysfunction.

What urologists need to know about ketamine-induced uropathy: A systematic review

AIMS

Ketamine is a general anesthetic. Dissociative effects and low cost led ketamine becoming an illegal recreational drug in young adults. Ketamine-induced uropathy (KIU) is one of the complications observed in abusers. This study aimed to provide a systematic literature review on KIU clinical presentation, pathophysiology, and treatments.

METHODS

We performed the literature search in PubMed, Web of Science, Scopus, and Embase using the terms ketamine and bladder. English papers on human and animal studies were accepted.

RESULTS

A total of 75 papers were selected. Regular ketamine users complain about severe storage symptoms and pelvic pain. Hydronephrosis may develop in long-term abusers and is correlated to the contracted bladder, ureteral stenosis, or vesicoureteral reflux due to ureteral involvement and/or bladder fibrosis. Cystoscopy shows ulcerative cystitis. Ketamine in urine might exert direct toxicity to the urothelium, disrupting its barrier function and enhancing cell apoptosis. The presence of ketamine/ions in the bladder wall result in neurogenic/IgE-mediated inflammation, stimulation of the inducible nitric oxide synthase-cytokines-cyclooxygenase pathway with persistent inflammation and fibrosis. Abstinence is the first therapeutic step. Anti-inflammatory drugs, analgesics and anticholinergics, intravesical instillation of hyaluronic acid, hydrodistension and intravesical injection of botulin toxin-A were helpful in patients with early-stage KIU. In patients with end-stage disease, the control of intractable symptoms and the increase of bladder capacity were the main recommendations to perform augmentation enterocystoplasty.

CONCLUSIONS

KIU is becoming a worldwide health concern, which should be taken into account in the differential diagnosis of ulcerative cystitis.

N-acetylcysteine prevents bladder tissue fibrosis in a lipopolysaccharide-induced cystitis rat model

Therapeutic options for non-Hunner type interstitial cystitis (IC), which is histologically characterized by fibrosis and mast cell infiltration, are limited. We developed a rat model that replicates chronic inflammation and fibrosis and evaluated the therapeutic effect of N-acetylcysteine (NAC), a well-known anti-fibrotic agent, on the model. Intravesical instillation of lipopolysaccharide (LPS, 750 μg) after protamine sulfate (10 mg) was conducted twice per week for five consecutive weeks. One week after final instillation, 200 mg/kg NAC (n = 10, IC + NAC group) or phosphate-buffered saline (n = 10, IC group) was daily injected intraperitoneally once daily for 5 days. LPS instillation induced bladder fibrosis, mast cell infiltration, and apoptotic tissue damage. Functionally, LPS insult led to irregular micturition, decreased inter-contraction intervals, and decreased micturition volume. NAC significantly improved most of the voiding parameters and reversed histological damages including fibrosis. NAC inhibited the induction and nuclear localization of phospho-Smad2 protein in bladder tissues and the upregulation of genes related to fibrosis, such as Tgfb2, Tgfb3, Smad2, Smad3, Cxcl10, and Card10. This is the first study to demonstrate the beneficial effects on NAC in restoring voiding function, relieving tissue fibrosis and related bladder injuries, in the LPS-induced cystitis rat model.

Ketamine induces reactive oxygen species and enhances autophagy in SV-HUC-1 human uroepithelial cells

This study was aimed at exploring the underlying mechanisms of ketamine in the SV-40 immortalized human ureteral epithelial (SV-HUC-1) cells. The viability and apoptosis of SV-HUC-1 cells treated with 0.01, 0.1, and 1 mM ketamine were respectively detected via cell counting kit-8 (CCK-8) assay and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) staining. Reactive oxygen species (ROS) level was measured through ROS probe staining. Apoptosis-related proteins (B-cell lymphoma 2 [Bcl-2] and Bax) and autophagy-associated proteins (light chain 3-I [LC3-I] and LC3-II) were determined by western blot or immunofluorescent assay. Additionally, transmission electron microscopy (TEM) was used to evaluate the formation of autophagosomes. After cotreatment of 3-methyladenine (3-MA) or N-acetyl-l-cysteine (NAC), the biological functions of SV-HUC-1 cells were analyzed to determine the association of ROS with cell viability and autophagy. CCK-8 assay and TUNEL staining indicated that ketamine effectively decreased the viability of SV-HUC-1 cells and accelerated apoptosis of SV-HUC-1 cells through regulating the expression level of IKBα (phospho), nuclear factor кB (P65), Bcl-2, and Bax proteins. Enhanced ROS production was also confirmed in ketamine-treated SV-HUC-1 cells treated with ketamine. Ketamine-induced autophagosomes in SV-HUC-1 cells were observed by means of TEM, and increased levels of LC3 II/I ratio and Beclin 1 were examined through western blot and immunofluorescent assay. Furthermore, ketamine exerted effects on SV-HUC-1 cells in a dose-dependent and time-dependent manner. Additionally, cotreatment of NAC with 3-MA significantly attenuated the ROS level and suppressed the cell autophagy. Ketamine promoted SV-HUC-1 cell autophagy and impaired the cell viability of SV-HUC-1 cells by inducing ROS.

The Therapeutic Effect of Human Embryonic Stem Cell-Derived Multipotent Mesenchymal Stem Cells on Chemical-Induced Cystitis in Rats

Purpose

To evaluate the therapeutic effect of human embryonic stem cell (hESC)-derived multipotent mesenchymal stem cells (M-MSCs) on ketamine-induced cystitis (KC) in rats.

Methods

To induce KC, 10-week-old female rats were injected with 25-mg/kg ketamine hydrochloride twice weekly for 12 weeks. In the sham group, phosphate buffered saline (PBS) was injected instead of ketamine. One week after the final injection of ketamine, the indicated doses (0.25, 0.5, and 1×10⁶ cells) of M-MSCs (KC+M-MSC group) or PBS vehicle (KC group) were directly injected into the bladder wall. One week after M-MSC injection, the therapeutic outcomes were evaluated via cystometry, histological analyses, and measurement of gene expression. Next, we compared the efficacy of M-MSCs at a low dose (1×10⁵ cells) to that of an identical dose of adult bone marrow (BM)-derived MSCs.

Results

Rats in the KC group exhibited increased voiding frequency and reduced bladder capacity compared to rats of the sham group. However, these parameters recovered after transplantation of M-MSCs at all doses tested. KC bladders exhibited markedly increased mast cell infiltration, apoptosis, and tissue fibrosis. Administration of M-MSCs significantly reversed these characteristic histological alterations. Gene expression analyses indicated that several genes associated with tissue fibrosis were markedly upregulated in KC bladders. However the expression of these genes was significantly suppressed by the administration of M-MSCs. Importantly, M-MSCs ameliorated bladder deterioration in KC rats after injection of a low dose (1×10⁵) of cells, at which point BM-derived MSCs did not substantially improve bladder function.

Conclusions

This study demonstrates for the first time the therapeutic efficacy of hESC-derived M-MSCs on KC in rats. M-MSCs restored bladder function more effectively than did BM-derived MSCs, protecting against abnormal changes including mast cell infiltration, apoptosis and fibrotic damage.

Clinical significance of interleukin‑6 and inducible nitric oxide synthase in ketamine‑induced cystitis

Ketamine is an ionotropic glutamatergic N-methyl-D-aspartate receptor antagonist, which is widely used among recreational drug abusers. Ketamine abusers exhibit substantially reduced bladder capacity, which can lead to urinary frequency. The molecular pathogenesis of ketamine-induced cystitis has been scarcely reported. Given previous clinical findings, it may be hypothesized that pathological alterations in smooth muscle cells (SMCs) of the urinary bladder serve a crucial role in the mechanism underlying cystitis. In the present study, two lineages of SMCs, one from differentiated foreskin-derived fibroblast-like stromal cells and the other from cultured normal aortic SMCs, were used to study ketamine-induced molecular alterations. Polymerase chain reaction was used to study the effects of ketamine on oxidative stress. The effects of adjuvant chemo-therapy with cyclophosphamide (CTX) were also investigated. The results indicated that the expression levels of interleukin-6 and inducible nitric oxide synthase (iNOS) were decreased, whereas collagen expression and deposition were increased in ketamine-treated SMCs. Conversely, treatment with CTX restored the expression of iNOS, which may prevent or limit oxidative damage. In conclusion, the present study demonstrated that ketamine may induce several molecular alterations in SMCs and these changes may be associated with the clinical symptoms observed in ketamine abusers. In addition, the specific chemotherapeutic agent CTX may reverse these ketamine-induced aberrations.

Ketamine-induced bladder fibrosis involves epithelial-to-mesenchymal transition mediated by transforming growth factor-β1

Bladder wall fibrosis is a major complication of ketamine-induced cystitis (KC), but the underlying pathogenesis is poorly understood. The aim of the present study was to elucidate the mechanism of ketamine-induced fibrosis in association with epithelial-to-mesenchymal transition (EMT) mediated by transforming growth factor-β1 (TGF-β1). Sprague-Dawley rats were randomly distributed into four groups, which received saline, ketamine, ketamine combined with a TGF-β receptor inhibitor (SB-505124) for 16 wk, or 12 wk of ketamine and 4 wk of abstinence. In addition, the profibrotic effect of ketamine was confirmed in SV-40 immortalized human uroepithelial (SV-HUC-1) cells. The ketamine-treated rats displayed voiding dysfunction and decreased bladder compliance. Bladder fibrosis was accompanied by the appearance of a certain number of cells expressing both epithelial and mesenchymal markers, indicating that epithelial cells might undergo EMT upon ketamine administration. Meanwhile, the expression level of TGF-β1 was significantly upregulated in the urothelium of bladders in ketamine-treated rats. Treatment of SV-HUC-1 cells with ketamine increased the expression of TGF-β1 and EMT-inducing transcription factors, resulting in the downregulation of E-cadherin and upregulation of fibronectin and α-smooth muscle actin. Administration of SB-505124 inhibited EMT and fibrosis both in vitro and vivo. In addition, withdrawal from ketamine did not lead to recovery of bladder urinary function or decreased fibrosis. Taken together, our study shows for the first time that EMT might contribute to bladder fibrosis in KC. TGF-β1 may have an important role in bladder fibrogenesis via an EMT mechanism.

Ketamine Analog Methoxetamine Induced Inflammation and Dysfunction of Bladder in Rats

The novel synthetic psychoactive ketamine analog methoxetamine is reportedly being used for recreational purposes. As ketamine use can result in urinary dysfunction, we conducted the present study to investigate how methoxetamine affects the bladder. A cystometry investigation showed that female Sprague-Dawley rats experienced increased micturition frequency bladder dysfunction after receiving a daily intraperitoneal injection of 30 mg/kg methoxetamine or ketamine for periods of 4 or 12 weeks. Histologic examinations of rat bladder tissue revealed damaged urothelium barriers, as well as evidence of inflammatory cell infiltration and matrix deposition. The drug-treated rats showed significantly upregulated levels of pro-inflammatory cytokines such as IL-1β, IL-6, CCL-2, CXCL-1, CXCL-10, NGF, and COX-2. In addition, interstitial fibrosis was confirmed by increased levels of collagen I, collagen III, fibronectin and TGF-β. Besides direct toxic effect on human urothelial cells, methoxetaminealso induced the upregulation related cytokines. Our results indicate that long term methoxetamine treatment can induce bladder dysfunction and inflammation in rats. Methoxetamine was confirmed to produce direct toxic and pro-inflammatory effects on human urothelial cells. Methoxetamine-associated bladder impairment may be similar to ketamine-induced cystitis.

Mesenchymal stem cells protect against the tissue fibrosis of ketamine-induced cystitis in rat bladder

Abuse of the hallucinogenic drug ketamine promotes the development of lower urinary tract symptoms that resemble interstitial cystitis. The pathophysiology of ketamine-induced cystitis (KC) is largely unknown and effective therapies are lacking. Here, using a KC rat model, we show the therapeutic effects of human umbilical cord-blood (UCB)-derived mesenchymal stem cells (MSCs). Daily injection of ketamine to Sprague-Dawley rats for 2-weeks resulted in defective bladder function, indicated by irregular voiding frequency, increased maximum contraction pressure, and decreased intercontraction intervals and bladder capacity. KC bladders were characterized by severe mast-cell infiltration, tissue fibrosis, apoptosis, upregulation of transforming growth factor-β signaling related genes, and phosphorylation of Smad2 and Smad3 proteins. A single administration of MSCs (1 × 10(6)) into bladder tissue not only significantly ameliorated the aforementioned bladder voiding parameters, but also reversed the characteristic histological and gene-expression alterations of KC bladder. Treatment with the antifibrotic compound N-acetylcysteine also alleviated the symptoms and pathological characteristics of KC bladder, indicating that the antifibrotic capacity of MSC therapy underlies its benefits. Thus, this study for the first-time shows that MSC therapy might help to cure KC by protecting against tissue fibrosis in a KC animal model and provides a foundation for clinical trials of MSC therapy.