Abnormal Sensory Protein Expression and Urothelial Dysfunction in Ketamine-Related Cystitis in Humans

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.

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.

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.

Dysregulation of bladder corticotropin-releasing hormone receptor in the pathogenesis of human interstitial cystitis/bladder pain syndrome

Stress is associated with exacerbated symptoms in patients with interstitial cystitis/bladder pain syndrome (IC/BPS). To investigate the mechanism of stress implicated on IC/BPS, we investigated expression of stress-response receptor corticotropin-releasing hormone receptor (CRHR) in bladder from IC/BPS patients. Twenty-three IC/BPS patients with Hunner’s lesion (HIC), 51 IC/BPS patients without Hunner’s lesion (NHIC), and 24 patients with stress urinary incontinence as controls were enrolled. Cystoscopic biopsies of bladder wall including mucosa and submucosa were obtained from all patients. Western blotting was used to investigate the bladder expression of the CRHR1 and CRHR2. Immunochemical staining revealed CRHR1 expression was mainly located in the submucosa while CRHR2 expression was mainly in uroepithelial cells. Compared to control subjects, the CRHR1 expression was significantly higher, while CRHR2 expression was significantly lower in IC/BPS patients. Further analysis of patients with HIC, NHIC, and control subjects showed that bladder in patients with HIC had significantly higher expressions of CRHR1 and significantly lower CRHR2. CRHR2 expression was significantly negatively correlated with O’Leary-Sant score and bladder pain. Our results indicate dysregulation of bladder CRHR1 and CRHR2 in patients with IC/BPS, and suggest CRH signaling may be associated with IC/BPS symptoms.