Metallothionein overexpression of bladder biopsies associated with tissue hypoxia in patients with interstitial cystitis/painful bladder syndrome

Anti-inflammatory effect of sea buckthorn in an HCl-induced cystitis rat model

PURPOSE

Although the mechanism underlying interstitial cystitis/bladder pain syndrome (IC/BPS) remains unclear, oxidative stress is suggested to be implicated in IC/BPS development. Sea buckthorn (SB; Hippophae rhamnoides L.) contains several compounds with antioxidant properties. In addition, intravesical application of hydrochloric acid (HCl) in rats induces histological changes similar to those observed in humans with IC. Therefore, the aim of this study was to evaluate the anti-inflammatory effects of SB in an HCl-induced rat cystitis model.

MATERIALS AND METHODS

Twenty 8-week-old female Sprague-Dawley rats were instilled with HCl in their bladders to create an IC/BPS model. The model rats were divided into three groups and orally administrated distilled water (control, n=4), concentrated SB (n=8), or pentosan polysulfate (PPS, n=8) daily. Pathologic inflammation grade (H&E staining), number of mast cells per square millimeter (toluidine blue staining), fibrotic changes (Masson's trichrome staining), and apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling staining) of bladder tissue samples were compared among the groups.

RESULTS

Compared to the control group, the SB and PPS groups showed reduced edema (5.25±0.96 vs. 2.25±0.46 vs. 2.50±0.54, p=0.004, p=0.005, respectively), number of mast cells (12.5±3.6 vs. 6.8±1.9 vs. 6.6±1.8, p=0.010, p=0.002, respectively), ratio of fibrotic submucosal tissue (63.9%±7.0% vs. 43.6%±9.9% vs. 40.5%±5.2%, p<0.001, p<0.001, respectively), and ratio of apoptotic nucleus (40.7%±11.7% vs. 7.7%±6.5% vs. 5.1%±4.9%, p<0.001, p<0.001, respectively).

CONCLUSIONS

SB exhibited anti-inflammatory effects comparable to those of PPS in the HCl-induced chemical cystitis model.

MIF-Modulated Spinal Proteins Associated with Persistent Bladder Pain: A Proteomics Study

Bladder pain is a prominent symptom in Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS). We studied spinal mechanisms of bladder pain in mice using a model where repeated activation of intravesical Protease Activated Receptor-4 (PAR4) results in persistent bladder hyperalgesia (BHA) with little or no bladder inflammation. Persistent BHA is mediated by spinal macrophage migration inhibitory factor (MIF), and is associated with changes in lumbosacral proteomics. We investigated the contribution of individual spinal MIF receptors to persistent bladder pain as well as the spinal proteomics changes associated with relief of persistent BHA by spinal MIF antagonism. Female mice with persistent BHA received either intrathecal (i.t.) MIF monoclonal antibodies (mAb) or mouse IgG1 (isotype control antibody). MIF antagonism temporarily reversed persistent BHA (peak effect: 2 h), while control IgG1 had no effect. Moreover, i.t. antagonism of the MIF receptors CD74 and C-X-C chemokine receptor type 4 (CXCR4) partially reversed persistent BHA. For proteomics experiments, four separate groups of mice received either repeated intravesical scrambled peptide and sham i.t. injection (control, no pain group) or repeated intravesical PAR4 and: sham i.t.; isotype IgG1 i.t. (15 μg); or MIF mAb (15 μg). L6-S1 spinal segments were excised 2 h post-injection and examined for proteomics changes using LC-MS/MS. Unbiased proteomics analysis identified and relatively quantified 6739 proteins. We selected proteins that showed significant changes compared to control (no pain group) after intravesical PAR4 (sham or IgG i.t. treatment) and showed no significant change after i.t. MIF antagonism. Six proteins decreased during persistent BHA (V-set transmembrane domain-containing protein 2-like confirmed by immunohistochemistry), while two proteins increased. Spinal MIF antagonism reversed protein changes. Therefore, spinal MIF and MIF receptors mediate persistent BHA and changes in specific spinal proteins. These novel MIF-modulated spinal proteins represent possible new targets to disrupt spinal mechanisms that mediate persistent bladder pain.

Lumbosacral spinal proteomic changes during PAR4-induced persistent bladder pain

Repeated intravesical activation of protease-activated receptor-4 (PAR4) in mice results in persistent bladder hyperalgesia (BHA). We investigated spinal proteomic changes associated with persistent BHA. Persistent BHA was induced in female mice by repeated (3x; days 0,2,4; n = 9) intravesical instillation of PAR4 activating peptide (PAR4-AP) while scrambled peptide served as the control (no pain; n = 9) group. The threshold to lower abdominal von Frey stimulation was recorded prior to and during treatment. On day 7, L6-S1 spinal segments were excised and examined for proteomic changes using LC-MS/MS. In-depth, unbiased proteomic tandem-mass tag (TMT) analysis identified and relatively quantified 6739 proteins. We identified significant changes with 29 decreasing and 51 increasing proteins in the persistent BHA group and they were associated with neuroprotection, redox modulation, mitochondrial factors, and neuronal-related proteins. In an additional experiment, decreases in protein levels were confirmed by immunohistochemistry for metallothionein 1/2. Our results show that persistent bladder pain is associated with central (spinal) protein changes. Previous work showed that PAR4-induced bladder pain is mediated, at least in part by spinal MIF. Further functional studies of these top changing proteins may lead to the discovery of novel potential therapeutic targets at the spinal level to modulate persistent bladder pain. Future studies will examine the effect of spinal MIF antagonism on PAR4-induced spinal proteomics associated with persistent bladder pain.

Platelet Lysate Therapy Attenuates Hypoxia Induced Apoptosis in Human Uroepithelial SV-HUC-1 Cells through Regulating the Oxidative Stress and Mitochondrial-Mediated Intrinsic Apoptotic Pathway

(1) Background: Ischemia/hypoxia plays an important role in interstitial cystitis/bladder pain syndrome (IC/BPS). Platelet-rich plasma (PRP) has been shown to relieve symptoms of IC/BPS by regulating new inflammatory processes and promoting tissue repair. However, the mechanism of action of PRP on the IC/BPS bladder remains unclear. We hypothesize that PRP might protect the urothelium during ischemia/hypoxia by decreasing apoptosis. (2) Methods: SV-HUC-1 cells were cultured under hypoxia for 3 h and treated with or without 2% PLTGold^® human platelet lysate (PL). Cell viability assays using trypan blue cell counts were examined. Molecules involved in the mitochondrial-mediated intrinsic apoptosis pathway, HIF1α, and PCNA were assessed by Western blot analysis. The detection of apoptotic cells and CM-H2DCFDA, an indicator of reactive oxygen species (ROS) in cells, was analyzed by flow cytometry. (3) Results: After 3 h of hypoxia, the viability of SV-HUC-1 cells and expression of PCNA were significantly decreased, and the expression of ROS, HIF1α, Bax, cytochrome c, caspase 3, and early apoptosis rate were significantly increased, all of which were attenuated by PL treatment. The addition of the antioxidant N-acetyl-L-cysteine (NAC) suppressed the levels of ROS induced by hypoxia, leading to inhibition of late apoptosis. (4) Conclusions: PL treatment could potentially protect the urothelium from apoptosis during ischemia/hypoxia by a mechanism that modulates the expression of HIF1α, the mitochondria-mediated intrinsic apoptotic pathway, and reduces ROS.

Urine Oxidative Stress Biomarkers as Novel Biomarkers in Interstitial Cystitis/Bladder Pain Syndrome

Both hypoxia and chronic suburothelial inflammation are important pathophysiological findings in patients with interstitial cystitis/bladder pain syndrome (IC/BPS). This study investigated the roles of urine oxidative stress biomarkers and inflammatory cytokines in patients with IC/BPS. Urine samples were collected from 159 IC/BPS patients and 28 controls. The targeted analytes included oxidative stress biomarkers (8-OHdG, 8-isoprostane, and total antioxidant capacity) and inflammatory cytokines (MCP-1, RANTES, CXCL10, Eotaxin, MIP-1β, and IL-8). IC/BPS patients were classified into four clinical subgroups, based on the glomerulation grade and the maximal bladder capacity under anesthesia. Patients with IC/BPS had urine oxidative stress biomarkers and inflammatory cytokines profiles that were distinct from those of the controls and among each subgroup. Both 8-OHdG and 8-isoprostane showed a high diagnostic ability to distinguish type 2 IC/BPS patients (as classified by the European Society for the Study of Interstitial Cystitis) from controls. Additionally, they both showed positive and negative correlations with the glomerulation grade and the maximal bladder capacity under anesthesia, respectively. Limitations included intra-individual variation and sex influence. Urine oxidative stress biomarkers might have a role in diagnosing IC/BPS and differentiating its clinical subtypes. In addition to inflammatory cytokines, urine oxidative stress biomarkers have the potential to be novel biomarkers in patients with IC/BPS.

Urine-based regenerative RNA biomarkers for urinary bladder wound healing

Background: This study aimed to investigate the expression of regeneration-related genes in canine urine during bladder repair. Materials & methods: Canine urine samples were collected after partial cystectomy. Regenerative mRNA of hypoxia-inducible factor (HIF), vascular endothelial growth factor (VEGF), key stem cell transcription factors and cholinergic signals were detected. Results: HIF-1α, VEGF, CD44, IL-6 and prominin-1 expression in canine urine after partial cystectomy exhibited two similar peaks at ∼2 weeks. HIF-1α and VEGF expression were higher in the afternoon than the morning. The expression of key stem cell transcription factors and cholinergic signals also exhibited a rhythm along with bladder healing. Conclusions: The expression of HIF-1α, VEGF, key stem cell transcription factors and cholinergic signals exhibited a time curve distribution during canine bladder healing. The expression trend of some regenerative genes was similar during bladder healing, and a cooperative effect may exist.

Expression profile of urothelial transcription factors in bladder biopsies with interstitial cystitis

OBJECTIVES

To characterize interstitial cystitis pathology based on the expression profile of urothelial tissue-specific master transcription factors.

METHODS

Bladder carcinoma cell lines derived from the urothelial stem cells (epithelial or mesenchymal) were used to identify candidate urothelial master transcription factors. Gene expression was measured with quantitative reverse transcription polymerase chain reaction. From the initial screening of 170 transcription factors (human homologs of Drosophila segmentation genes and known master transcription factors from a database), 28 transcription factors were selected. Subsequently, messenger ribonucleic acid from bladder biopsies of interstitial cystitis patients was purified, and gene expression levels of known urothelial marker genes and candidate master transcription factors were measured. Multivariate expression data were analyzed with spss software.

RESULTS

Factor analysis decomposed the expression profile into four axes: principal axis 1 included retinoic acid receptors and 17 candidate master transcription factors. Principal axis 2 included KRT5 and five candidates. Principal axis 3 included transcription factor TP63 and two candidates. Principal axis 4 included SHH and two candidates. Principal component analysis segregated biopsies from Hunner's lesion in the principal component 1 (retinoic acid)/principal component 2 (SOX13)/principal component 3 (TP63) space.

CONCLUSIONS

Urothelial master transcription factors could serve as novel diagnostic markers and potentially explain the molecular pathology of interstitial cystitis.

Propylthiouracil, Perchlorate, and Thyroid-Stimulating Hormone Modulate High Concentrations of Iodide Instigated Mitochondrial Superoxide Production in the Thyroids of Metallothionein I/II Knockout Mice

BACKGROUND

Increased oxidative stress has been suggested as one of the underlying mechanisms in iodide excess-induced thyroid disease. Metallothioneins (MTs) are regarded as scavengers of reactive oxygen species (ROS) in oxidative stress. Our aim is to investigate the effects of propylthiouracil (PTU), a thyroid peroxidase inhibitor, perchlorate (KClO₄), a competitive inhibitor of iodide transport, and thyroid stimulating hormone (TSH) on mitochondrial superoxide production instigated by high concentrations of iodide in the thyroids of MT-I/II knockout (MT-I/II KO) mice.

METHODS

Eight-week-old 129S7/SvEvBrd-Mt1(tm1Bri) Mt2(tm1Bri)/J (MT-I/II KO) mice and background-matched wild type (WT) mice were used.

RESULTS

By using a mitochondrial superoxide indicator (MitoSOX Red), lactate dehydrogenase (LDH) release, and methyl thiazolyl tetrazolium (MTT) assay, we demonstrated that the decreased relative viability and increased LDH release and mitochondrial superoxide production induced by potassium iodide (100 μM) can be relieved by 300 μM PTU, 30 μM KClO₄, or 10 U/L TSH in the thyroid cell suspensions of both MT-I/II KO and WT mice (P<0.05). Compared to the WT mice, a significant decrease in the relative viability along with a significant increase in LDH release and mitochondrial superoxide production were detected in MT-I/II KO mice(P<0.05).

CONCLUSION

We concluded that PTU, KClO₄, or TSH relieved the mitochondrial oxidative stress induced by high concentrations of iodide in the thyroids of both MT-I/II KO and WT mice. MT-I/II showed antioxidant effects against high concentrations of iodide-induced mitochondrial superoxide production in the thyroid.

Impaired Na(+)/K(+)-ATPase Function in Patients with Interstitial Cystitis/Painful Bladder Syndrome

Na(+)/K(+)-ATPase (NKA) is abundantly expressed in the basolateral membrane of epithelial cells, which is necessary for tight junction formation. The tight junction is an urothelial barrier between urine and the underlying bladder. Impairment of tight junctions allows migration of urinary solutes in patients with interstitial cystitis/painful bladder syndrome (IC/PBS). We evaluated NKA expression and activity in bladder samples from patients with IC/PBS. The study group consisted of 85 patients with IC/PBS, and the control group consisted of 20 volunteers. Bladder biopsies were taken from both groups. We determined the expression and distribution of NKA using NKA activity assays, immunoblotting, immunohistochemical staining, and immunofluorescent staining. The protein levels and activity of NKA in the study group were significantly lower than the control group (1.08 ± 0.06 vs. 2.39 ± 0.29 and 0.60 ± 0.04 vs. 1.81 ± 0.18 µmol ADP/mg protein/hour, respectively; P < 0.05). Additionally, immunofluorescent staining for detection of CK7, a marker of the bladder urothelium, predominantly colocalized with NKA in patients in the study group. Our results demonstrated the expression and activity of NKA were decreased in bladder biopsies of patients with IC/PBS. These findings suggest that NKA function is impaired in the bladders from patients with IC/PBS.

From bladder to systemic syndrome: concept and treatment evolution of interstitial cystitis

Interstitial cystitis, presently known as bladder pain syndrome, has been recognized for over a century but is still far from being understood. Its etiology is unknown and the syndrome probably harbors different diseases. Autoimmune dysfunction, urothelial leakage, infection, central and peripheral nervous system dysfunction, genetic disease, childhood trauma/abuse, and subsequent stress response system dysregulation might be implicated. Management is slowly evolving from a solo act by the end-organ specialist to a team approach based on new typing and phenotyping of the disease. However, oral and invasive treatments are still largely aimed at the bladder and are based on currently proposed pathophysiologic mechanisms. Future research will better define the disease, permitting individualization of treatment.