Effects of human Muse cells on bladder inflammation, overactivity, and nociception in a chemically induced Hunner-type interstitial cystitis-like rat model

INTRODUCTION AND HYPOTHESIS

We investigated the effects of locally administered human multilineage-differentiating stress enduring (Muse) cells, nontumorigenic pluripotent-like endogenous stem cells, on bladder tissues, function, and nociceptive behavior in a chemically induced Hunner-type interstitial cystitis (HIC)-like rat model without immunosuppressant.

METHODS

Chemical cystitis was induced by intravesical instillation of 0.2 N hydrochloride (HCl) for 15 min in female F344 rats. SSEA-3⁺ Muse cells, SSEA-3^- non-Muse cells or Hanks' balanced salt solution (HBSS; vehicle) were injected into the anterior and posterior bladder wall at each 1×10⁴ cells/10 μl 6 h after HCl application. The sham group received HBSS without HCl instillation. Urinary frequency was assessed using metabolic cages, cystometrograms, nociceptive behavior, and histological analysis of the bladder and L6 spinal cord.

RESULTS

Increases in urinary frequency and decreases in bladder capacity compared with the sham group were observed in the vehicle and non-Muse groups, but not in the Muse group, at 1 week. Significant increases in nociceptive behavior compared with the sham group and the expression of TNFα in the bladder and c-Fos in the bilateral dorsal horns of L6 spinal cord were also observed in the vehicle and non-Muse groups, whereas these changes were not seen in the Muse group at 1 week. Histological analysis exhibited a higher proportion of injected Muse cells remaining in the urothelial basal layer and lamina propria of the bladder than non-Muse cells until 4 weeks.

CONCLUSIONS

Muse cell therapy could be a promising modality for treating HIC.

Neuroinflammatory gene expression analysis reveals potential novel mediators and treatment targets in interstitial cystitis with Hunner lesions

Background

We sought to study differential neuroinflammatory gene expression in men with interstitial cystitis (IC) with Hunner lesions compared with asymptomatic controls using NanoString, which uses barcoded probes to measure hundreds of genes. IC is a heterogenous condition lacking reliable biomarkers, and a subset of patients exhibits Hunner lesions, implicating the bladder as an inflammatory pain generator.

Methods

Blood, urine, and bladder biopsies were collected from 6 men with IC and Hunner lesions. 7 asymptomatic controls had blood and urine collected and 2 benign bladder biopsies were obtained from our tissue bank. RNA was isolated and analyzed with NanoString Human Neuroinflammation panel. Gene expression was considered significant if there was a >1.5-fold change and adjusted P value <0.05 compared with controls.

Results

Mean patient age was 61.5 years with 8 years median symptom duration. In bladder tissue, while many cytokine and chemokine genes had higher expression as expected (e.g., TNF, CXCL10), other significant genes included TRPA1 (1098-fold increased, expressed in pain sensing neurons) and TNFRSF17 (735-fold, B-cell related). In urine, there was 114-fold increase in S1PR4, which mediates pain via TRP-dependent pathways. A patient on cyclosporine had lower inflammatory gene expression levels relative to other IC patients, but no difference in TRPA1.

Conclusions

Men with IC and Hunner lesions have a diverse set of neuroinflammatory genes with differential expression compared to controls. We identified genes linked to neuropathic pain through the TRP pathway and this expression was not reduced by cyclosporine. These findings open a new direction for biomarker and therapeutic discovery.

Phenotyping of interstitial cystitis/bladder pain syndrome

Interstitial cystitis/bladder pain syndrome is a chronic, potentially debilitating condition characterized by pain perceived to be related to the bladder in conjunction with lower urinary tract symptoms, and includes a wide variety of clinical phenotypes with diverse etiologies. Currently the only clinically relevant proven phenotype of interstitial cystitis/bladder pain syndrome is the Hunner lesion. Whether the presence of Hunner lesions is a hallmark of a distinct disease cohort or a potentially transient feature of non-Hunner lesion phenotype has been debated but remains controversial. There are few documented examples of a patient converting between the two forms. Growing clinical and basic evidence supports eliminating the Hunner lesion phenotype from the bladder pain syndrome umbrella and considering it a distinct disease. The Hunner lesion phenotype is characterized by distinct bladder histology, including subepithelial chronic inflammatory changes and epithelial denudation, and specific clinical characteristics (older onset age, severe bladder-centric symptoms, reduced bladder capacity, and favorable response to the lesion-targeted therapies). To define the Hunner lesion phenotype, it is necessary to develop an atlas of standardized images of cystoscopic (and, if possible, pathological) appearances of Hunner lesions. A true potential and clinically relevant phenotype of interstitial cystitis/bladder pain syndrome may be patients with non-bladder-centric symptoms, characterized by the affect dysregulation and somatic symptoms, and a greater bladder capacity in absence of Hunner lesions. In the present workshop, we concluded that the Hunner lesion is a valid phenotype and can reasonably be considered a disease in its own right. Assessment of bladder capacity and the extent of symptoms (bladder beyond or bladder centric) may help phenotyping of interstitial cystitis/bladder pain syndrome. Proper phenotyping is essential for the diagnosis and treatment of interstitial cystitis/bladder pain syndrome, and for facilitating research.

Clinical guidelines for interstitial cystitis and hypersensitive bladder updated in 2015

Clinical guidelines for interstitial cystitis and hypersensitive bladder have been updated as of 2015. The guidelines define interstitial cystitis by the presence of hypersensitive bladder symptoms (discomfort, pressure or pain in the bladder usually associated with urinary frequency and nocturia) and bladder pathology, after excluding other diseases explaining symptoms. Interstitial cystitis is further classified by bladder pathology; either Hunner type interstitial cystitis with Hunner lesions or non-Hunner type interstitial cystitis with mucosal bleeding after distension in the absence of Hunner lesions. Hypersensitive bladder refers to a condition, where hypersensitive bladder symptoms are present, but bladder pathology or other explainable diseases are unproven. Interstitial cystitis and hypersensitive bladder severely affect patients' quality of life as a result of disabling symptoms and/or comorbidities. Reported prevalence suggestive of these disorders varies greatly from 0.01% to >6%. Pathophysiology would be an interaction of multiple factors including urothelial dysfunction, inflammation, neural hyperactivity, exogenous substances and extrabladder disorders. Definite diagnosis of interstitial cystitis and hypersensitive bladder requires cystoscopy with or without hydrodistension. Most of the therapeutic options lack a high level of evidence, leaving a few as recommended therapeutic options.