Metaplastic transformation of urinary bladder epithelium: effect on mast cell recruitment, distribution, and phenotype expression

Single-cell RNA sequencing reveals the immune microenvironment and signaling networks in cystitis glandularis

Introduction

Cystitis glandularis (CG) is a rare chronic bladder hyperplastic disease that mainly manifests by recurrent frequent urination, dysuria and gross hematuria. The current lack of unified diagnosis and treatment criteria makes it essential to comprehensively describe the inflammatory immune environment in CG research.

Methods

Here, we performed scRNA-sequencing in CG patients for the first time, in which four inflamed tissues as well as three surrounding normal bladder mucosa tissues were included. Specifically, we isolated 18,869 cells to conduct bioinformatic analysis and performed immunofluorescence experiments.

Results

Our genetic results demonstrate that CG does not have the classic chromosomal variation observed in bladder tumors, reveal the specific effects of TNF in KRT15 epithelial cells, and identify a new population of PIGR epithelial cells with high immunogenicity. In addition, we confirmed the activation difference of various kinds of T cells during chronic bladder inflammation and discovered a new group of CD27-Switch memory B cells expressing a variety of immunoglobulins.

Discussion

CG was regarded as a rare disease and its basic study is still weak.Our study reveals, for the first time, the different kinds of cell subgroups in CG and provides the necessary basis for the clinical treatment of cystitis glandularis. Besides, our study significantly advances the research on cystitis glandularis at the cellular level and provides a theoretical basis for the future treatment of cystitis glandularis.

Cytokine expression in patients with bladder pain syndrome/interstitial cystitis ESSIC type 3C

PURPOSE

Bladder wall nitric oxide production in patients with bladder pain syndrome type 3C is increased compared to undetectable nitric oxide in patients with nonHunner bladder pain syndrome and healthy controls. However, the underlying mechanism/s of the increased nitric oxide production is largely unknown. We compared mRNA expression of a select group of cytokines in patients with bladder pain syndrome/interstitial cystitis type 3C and in pain-free controls.

MATERIALS AND METHODS

Cold cup biopsies from 7 patients with bladder pain syndrome type 3C and 6 healthy subjects were analyzed. mRNA expression of IL-4, 6, 10 and 17A, iNOS, TNF-α, TGF-β and IFN-γ was estimated by real-time polymerase chain reaction. IL-17 protein expression was determined by immunohistochemistry. Mast cells were labeled with tryptase to evaluate cell appearance and count.

RESULTS

IL-6, 10 and 17A, and iNOS mRNA levels as well as the number of mast cells infiltrating the bladder mucosa were significantly increased in patients with bladder pain syndrome type 3C compared to healthy controls. TNF-α, TGF-β and IFN-γ mRNA levels were similar in patients and controls. IL-17A expression at the protein level was up-regulated and localized to inflammatory cells and urothelium in patients with bladder pain syndrome type 3C.

CONCLUSIONS

Patients with bladder pain syndrome/interstitial cystitis had increased mRNA levels of IL-17A, 10 and 6, and iNOS. IL-17A might be important in the inflammatory process. To our knowledge the increase in IL-17A is a novel finding that may have new treatment implications.

Clinical characteristics differ considerably between phenotypes of bladder pain syndrome/interstitial cystitis

OBJECTIVE

Bladder pain syndrome/interstitial cystitis (BPS/IC) is one of the most bothersome conditions in urological practice. This syndrome includes a heterogeneous collection of underlying pathological conditions. Compared to the classic IC with a Hunner lesion, now denominated European Society for the Study of Interstitial Cystitis (ESSIC) type 3C, the non-Hunner type of BPS/IC appears different concerning demographic, endoscopic and histological findings, as well as the response to all forms of treatment. The objective of this study was to determine whether there are additional dissimilarities in clinical presentation between the main phenotypes of BPS/IC.

MATERIAL AND METHODS

In total, 393 BPS/IC patients (210 type 3C and 183 non-Hunner), diagnosed according to National Institute of Diabetes and Digestive and Kidney Diseases and ESSIC criteria, were studied by surveying the clinical records including micturition diaries.

RESULTS

In this clinical material, BPS/IC ESSIC type 3C accounted for 55% of cases. Patients with non-Hunner disease were on average 20 years younger at the time of diagnosis. Furthermore, there was a marked and significant difference in bladder capacity under general anaesthesia (p < 0.0001).

CONCLUSIONS

The findings in the present series, together with previously published reports by this group and by others, confirm the striking differences between the main forms of BPS/IC and underline the indispensability of adequate subtyping in clinical studies.

Epithelial metaplasia: adult stem cell reprogramming and (pre)neoplastic transformation mediated by inflammation?

Throughout adult life, new developmental commitment of adult stem cells causes metaplastic conversions to occur frequently in some organs. These reversible epithelial replacements are almost always observed in association with chronic inflammation and persistent irritation. Although metaplasia is not synonymous with dysplasia, clinical surveillance has demonstrated that these adaptive processes have an increased susceptibility to evolve into cancer. We propose that cytokines and other soluble factors released by both epithelial and inflammatory cells might alter the transcription-factor expression profile of stem cells and lead to the development of metaplasia. Furthermore, inflammatory mediators might also promote the malignant transformation of epithelial metaplasia by inducing genetic and epigenetic changes and by preventing the immune system from mounting an efficient anti-tumour immune response. A better understanding of the molecular mechanisms leading to metaplasia might help in the design of new therapies for neoplastic and degenerative diseases.

Human detrusor smooth muscle cells release interleukin-6, interleukin-8, and RANTES in response to proinflammatory cytokines interleukin-1β and tumor necrosis factor-α

OBJECTIVES

Recently, we have demonstrated that human detrusor smooth muscle cells in culture secrete the chemokine monocyte chemoattractant protein 1. In the present study, we extended these studies to include the effect of the proinflammatory cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta on IL-8, IL-6, and RANTES (regulated on activation, normal T cell expressed and secreted) release by human detrusor smooth muscle cells (HDSMCs) and examined their regulation.

METHODS

With ethical approval, detrusor muscle biopsies were obtained from patients with benign noninvasive bladder diseases undergoing control cystoscopy. HDSMCs were cultured using an explant technique and used at maximum third passage. HDSMCs were cultured in the presence or absence of TNF-alpha and IL-1beta. Supernatants were collected after 6, 12, and 24 hours. IL-8, IL-6, and RANTES were measured using enzyme-linked immunosorbent assays.

RESULTS

TNF-alpha and IL-1beta (0.01 to 100 ng/mL) induced secretion of IL-8, IL-6, and RANTES in a dose and time-dependent manner. The production of chemokines reached a maximum after 24 hours of incubation. In nonstimulated HDSMCs, the basal secretion of IL-8, IL-6, and RANTES was detectable. Induction of cytokine release by IL-1beta was synergistic with TNF-alpha.

CONCLUSIONS

These findings for the first time demonstrate that HDSMCs release IL-8, IL-6, and RANTES in response to IL-1beta and TNF-alpha. The constitutive and cytokine-stimulated production of chemokines and cytokines suggest that the human detrusor may contribute to mast cell infiltration into the bladder interstitium. The new evidence that HDSMCs secrete immunomodulatory proteins makes the detrusor muscle cell a target for anti-inflammatory therapy.

Mast cells in human bile duct obstruction

Surgical biopsy specimens obtained from 50 patients with secondary cholangitis caused by obstruction of the common bile duct were studied immunohistochemically. Data on the number and ultrastructural appearances of mast cells positive for tryptase, chymase, vasointestinal polypeptide (VIP), and substance P (SP) were obtained. The bile ducts from patients presenting combined chronic exacerbated cholangitis and chronic sclerotic cholangitis showed significantly higher numbers of mast cell types compared to the controls (P < 0.0001). Cases with sclerotic cholangitis alone had significantly lower number of cells than patients with chronic exacerbated cholangitis alone (P < or = 0.0001). Morphometric measurements of electron micrographs showed that mast cell granules containing VIP, SP and chymase were commensurable in size. Electron-lucent granules without reaction product (altered granules) and granules with focal distribution of the reaction product were observed in all types of mast cells. Furthermore, some nerve fibers positive for SP and VIP and serotonin-positive endocrine cells were observed in close proximity to the mast cells. In conclusion, the results of our study demonstrate the existence of different populations of mast cells, nerve structures and endocrine cells in the lower part of the human large bile duct, and suggest their participation in the development of pathological processes.

Cajal-like cells in the upper urinary tract: comparative study in various species

The interstitial cells of Cajal (ICC) play an important role in the control of gut motility. The recognition that the ICC cell membrane harbors the c-kit receptor (CD117) sparked rapid advancement in ICC research on the gut and certain pathologies using immunochemical and molecular methods. The question arises whether ICC exist in the upper urinary tract (UUT) and trigger motility. The present study analyzed the distribution of the c-kit receptor in the normal human UUT compared with various species. Immunohistochemistry (alkaline-phosphatase-anti-alkaline-phosphatase technique, immunofluorescence) was applied on serial sections using monoclonal and polyclonal antibodies recognizing the c-kit receptor. C-kit staining was compared with standard endothelial, epithelial, neurogenic, histiocytic, mast cell, and smooth muscle markers, as well as a negative control. Normal proximal, middle, and distal ureter segments were analyzed in rodents, carnivores, porcines, cow, and humans. In all species the c-kit receptor was detected in either round or spindle-shaped cells. Because of their antigenic profile, the round cells were identified as mast cells occurring in all layers of the ureteral wall except the urothelium and were more frequent in humans. In contrast, the population of spindle-shaped cells was marked only by anti-c-kit receptor antibodies, thus resembling ICC. These ICC-like cells were found among the inner and outer smooth muscle layers and in the lamina propria of all species. In humans, spindle-shaped cells were also found vertically oriented within the urothelium. Our morphological data present for the first time the distribution of ICC in the UUT of various species. The ubiquitous distribution in the entire pyeloureteral complex provides strong evidence that ICC generate electrical pacemaker activity within the UUT as an intrinsic system. Animal studies may help to understand the physiological importance of these ICC-like cells. The significance of these findings needs to be evaluated by functional studies and investigations of certain congenital pathologies with disturbance of the urinary outflow.

Current and future directions in diagnostic markers in interstitial cystitis

Interstitial cystitis (IC) is a chronic bladder disorder of unknown etiology that is often diagnosed by symptom criteria with or without cystoscopic findings. Several potential diagnostic markers have recently been described that may facilitate diagnosis of this disorder. A summary of the literature and a discussion regarding these biomarkers is provided, along with a brief discussion of new biomarkers presented at the meeting.

Structural examination of tryptase-, and VIP-positive mast cells in the common bile duct of patients with lithiasis

The morphology of tryptase-, and vasoactive intestinal polypeptide (VIP)-positive mast cells was examined immunohistochemically in 38 common bile ducts collected from patients with secondary chronic cholangitis and varying degrees of inflammatory activity. Mast cells numbers in chronic exacerbated and chronic sclerotic cholangitis were significantly higher as compared with those in controls (72.4 cells/mm2 and 25.2 cells/mm2 vs. 5.9 cells/mm2; p < 0.0001, Student's t test). The increased number of tryptase-positive mast cells in chronic exacerbated cholangitis correlated with the severeness of inflammatory infiltration. In cases of chronic exacerbated cholangitis, the increased number of mast cells was detected in conjunction with active fibroplasia. In chronic sclerotic cholangitis mast cells were lower in number as compared with exacerbated cholangitis and were observed in relation with inactive fibrosis. Numerous VIP-positive mast cells were found in all patients with cholangitis. Ultrastructural immunocytochemistry showed tryptase positivity to be localized over either electron-dense or particulate granules with a mean diameter of 0.261+/-0.073 microm or 0.171+/-0.053 microm, respectively. VIP positivity was formed as a finely or coarsely granular pattern over larger electron-dense granules of 0.475+/-0.14 microm in diameter. Tryptase-positive mast cells were located mainly in and around surface and glandular epithelium. The involvement of tryptase- and VIP-positive mast cells in inflammation, fibrosis and epithelial reactions in the common bile duct is discussed.

Mast cell involvement in interstitial cystitis: a review of human and experimental evidence

Interstitial cystitis (IC) is a heterogeneous syndrome of unknown etiology. Altered bladder glycosaminoglycans lining and bladder mastocytosis have been documented in IC. The objective of this article is to critically examine the published data on bladder mastocytosis in clinical, experimental, and animal studies, with particular emphasis on morphologic evidence of mast cell increase and activation. The literature on bladder mastocytosis and mast cell activation in IC is critically reviewed with particular reference to staining methodology, tryptase immunoreactivity, and electron microscopy. Data from humans and animal models of IC are included. Mastocytosis in IC is best documented by tryptase immunocytochemical staining. Standard surgical stains such as Giemsa and toluidine blue routinely underestimate the degree of mastocytosis. Mast cells are 6- to 8-fold higher in the detrusor compared with controls in "classic IC," and 2- to 3-fold higher in "nonulcerative" IC. Detrusor mastocytosis occurs in both classic and nonulcer IC. Mucosal mast cell increase is present in nonulcerative IC. Mast cell activation without typical exocytosis occurs in the mucosa and submucosa. Activation of mast cells, irrespective of bladder location or degree of mastocytosis, is significant. Mast cell-derived vasoactive and proinflammatory molecules may contribute to the pathogenesis of IC.

Intravesical bacillus Calmette-Guerin and dimethyl sulfoxide for treatment of classic and nonulcer interstitial cystitis: a prospective, randomized double-blind study

PURPOSE

We conducted a prospective, double-blind study with a crossover design of intravesical bacillus Calmette-Guerin (BCG) and dimethyl sulfoxide to determine whether patients with classic and nonulcer interstitial cystitis, respectively, might benefit from either regimen.

MATERIALS AND METHODS

A total of 21 patients, including 11 with classic and 10 with nonulcer interstitial cystitis, randomly underwent treatments with intravesical BCG or dimethyl sulfoxide and, if not improved, were treated with the other substance after a washout period. All 21 patients were evaluated with symptom questionnaires, including a visual analog pain scale and voiding diaries.

RESULTS

Regardless of regimen, there was no improvement in maximal functional capacity. There was a reduction in urinary frequency following dimethyl sulfoxide treatment but only in the classic subtype (p <0.05), whereas no reduction was seen following BCG in either subtype. A substantial pain decrease was noted in classic (p <0.05) as well as nonulcer (p <0.05) interstitial cystitis following dimethyl sulfoxide.

CONCLUSIONS

Intravesical BCG has been presented as a promising new option for treatment of interstitial cystitis. We failed to demonstrate benefit from this treatment. Dimethyl sulfoxide had no positive effect on maximal functional capacity but resulted in a significant reduction in pain and urinary frequency, although only in patients with classic interstitial cystitis.