Polaprezinc attenuates cyclophosphamide-induced cystitis and related bladder pain in mice

Renovation of Intestinal Barrier by Polydatin in Experimentally Induced Ulcerative Colitis: Comparative Ultrastructural Study with L-Carnosine

Ulcerative colitis (UC) is a chronic inflammatory bowel disease associated with intestinal epithelial barrier impairment. Polydatin (PD), a natural product isolated from Polygonum cuspidatum, is known to have an anti-inflammatory, antioxidant, and antiapoptotic effect. We attempted to compare the protective impact of PD pretreatment on alterations to the intestinal epithelial barrier and the colonic wall's ultrastructure accompanying ulcerative colitis to other conventional drugs in practice, primarily L-carnosine, which has not been addressed before. The rats were divided into 5 groups; 3 of them were treated with sulphasalazine (500 mg/kg), L-carnosine (30 mg/kg), and PD (45 mg/kg). All groups were administered their respective drugs 3 days before the UC was induced by acetic acid intra-rectally, and the treatment was continued until the 11th day. The disease activity index (DAI) was estimated, and a macroscopic scoring was established for the harvested colonic tissue. The tissues were extracted and processed for hematoxylin and eosin staining, caspase-3 immunohistochemical staining, electron microscopy, and biochemical analysis evaluating proinflammatory markers (IL-1β, TNF-α, and IL-6), myeloperoxidase (MPO), oxidative stress, and lipid peroxidation. Histopathological examination of colonic tissue showed that PD pretreatment effectively restored mucosal epithelial cells, intercellular tight junctions, goblet cells, and maintained the intestinal epithelial and endothelial barriers. PD suppressed MPO, proinflammatory markers, and malondialdehyde but enhanced superoxide dismutase and glutathione levels. It also hampered apoptosis, as evidenced by a reduction in caspase-3 expression. PD showed a significantly better response in preserving the intestinal epithelial barrier against acetic acid-induced colitis as compared to sulphasalazine and L-carnosine. These findings demonstrate the therapeutic role of PD for patients with UC.

Comparison of the Efficacy of Polaprezinc Plus Proton Pump Inhibitor and Rebamipide Plus Proton Pump Inhibitor Treatments for Endoscopic Submucosal Dissection-induced Ulcers

GOALS

We assessed the efficacy of polaprezinc plus proton pump inhibitor (PPI) treatment for endoscopic submucosal dissection (ESD)-induced ulcer healing compared with rebamipide plus PPI treatment.

BACKGROUND

ESD has been widely used as a local treatment option that cures gastric neoplasms. However, it causes large and deep artificial ulcers, and there are no guidelines with regard to the optimal treatment durations and drug regimens for ESD-induced ulcers. Polaprezinc is effective for promoting ulcer healing and helps enhance the quality of ulcer healing.

STUDY

Two hundred ten patients with ESD-induced ulcers were randomly allocated to treatment with polaprezinc (150 mg/d) plus pantoprazole (40 mg/d) or treatment with rebamipide (300 mg/d) plus pantoprazole (40 mg/d). We evaluated the ulcer healing rate and condition of the ulcer at 4 weeks after dissection. The χ2 or Fisher exact test and the Student t test were used.

RESULTS

The ulcer healing rates at 4 weeks after dissection in the polaprezinc plus pantoprazole treatment group were not inferior compared with those in the rebamipide plus pantoprazole treatment group, both in the intention-to-treat analysis (90.3% and 91.4%, respectively, P=0.523) and per-protocol analysis (89.9% and 91.1%, respectively, P=0.531). The short procedure time was an independent predictive factor for a high ulcer healing rate (odds ratio: 0.975; 95% confidence interval: 0.958-0.993; P=0.006).

CONCLUSION

The polaprezinc plus PPI treatment showed noninferiority to rebamipide plus PPI treatment in the ulcer healing rate at 4 weeks after ESD.

MicroRNA-495 alleviates ulcerative interstitial cystitis via inactivating the JAK-STAT signaling pathway by inhibiting JAK3

INTRODUCTION AND HYPOTHESIS

As a notable chronic disorder, the incidence of interstitial cystitis (IC) has been documented to have increased among the female population with activity in microRNA-495 (miR-495) implicated in this disease. The current study was aimed at elucidating the effects associated with miR-495 on the inflammatory response and bladder fibrosis in rats with ulcerative IC via the JAK-STAT pathway by targeting JAK3.

METHODS

Ulcerative IC rat models were established. The targeting relationship between JAK3 and miR-495 was evaluated using luciferase reporter assay. After gain- or loss-of-function assays, mast-cell infiltration was assessed using toluidine blue staining, bladder fibrosis using Masson staining, and NO content using nitrate reductase method. JAK3 protein expression was detected by immunohistochemistry, JAK3, STAT1, STAT3, TGFβ-1, Col-I, Col-III, JAK1, JAK2, p-STAT1, and p-STAT3 expression by RT-qPCR and Western blot analysis, and serum IL-6, IL-8, IL-10, IL-17, and TNF-α levels in rats by ELISA.

RESULTS

Following transfection of overexpressed miR-495 or siRNA-JAK3, a diminished degree of mast-cell infiltration, number of mast cells, bladder fibrosis, NO content, JAK3-positive expression, mRNA expression of JAK3, STAT1, STAT3, TGFβ-1, Col-I, Col-III, protein expression of JAK1, JAK2, JAK3, p-STAT1, p-STAT3, and expression of IL-6, IL-8, IL-10, IL-17, and TNF-α were identified.

CONCLUSIONS

Collectively, our key findings provide evidence supporting the notion that the overexpression of miR-495 ameliorates inflammatory response and bladder fibrosis in ulcerative IC rat models via inactivation of the JAK-STAT signaling pathway by inhibiting JAK3.

Novel catheter design enables transurethral catheterization of male mice

The male mouse is underrepresented in research of the urinary tract due to the difficulty of transurethral catheterization. As a result, there is a lack of analysis of sex differences in urinary tract research. Here, we present a novel catheter design and technique that enables urethral catheterization of male mice for bladder inoculation. Our catheterization technique uses the resistance met at the level of the external urinary sphincter and prostate to guide the retraction, positioning, and advancement of the catheter into the urinary bladder. We have shown that this method can be used to reproducibly catheterize 12 male mice with minimal urogenital trauma but cannot be used as a cystometric technique. This method will facilitate the expansion of research into sex differences in various genitourinary conditions that require transurethral catheterization of mice.

Intrarectally administered polaprezinc attenuates the development of dextran sodium sulfate-induced ulcerative colitis in mice

Polaprezinc (PZ), a chelate of zinc and L-carnosine, has been widely used in the treatment of gastric ulcers since 1994. In recent years, researchers have found PZ to have a beneficial effect on various experimentally induced models of colitis in mice. In the present study, 6% dextran sodium sulfate (DSS) was used to induce a model of ulcerative colitis (UC) in Institute of Cancer Research mice. The therapeutic effect and mechanism of PZ action in a model of UC was studied in order to provide an experimental basis for the clinical application of PZ in UC treatment. The effect of PZ on UC was evaluated in five groups of mice: A vehicle control only group, a DSS model control group (DSS, 6%), a validated treatment control group (DSS 6% + Mesalamine), a low-dose PZ treatment group (DSS 6% + PZ 60 mg/kg) and a high-dose PZ group (DSS 6% + PZ 120 mg/kg). After the animals were sacrificed, blood was collected and the serum levels of NF-κB and tumor necrosis factor-α (TNF-α) were measured. Changes in histology were observed by light microscopy. The protein levels of AKT, phosphorylated AKT and heat shock protein 70 (HSP70) were determined by western blot analysis. The results suggested that PZ reduced the DSS-induced increase in the inflammatory proteins TNF-α and NF-κB in the UC model. The high-dose of PZ also increased the HSP70 protein level, inhibited AKT phosphorylation in a DSS-induced UC animal model, and decreased white blood cell and neutrophil % counts compared to levels in an untreated DSS control group. Histopathology indicated that the mice of the DSS model group had irregular colonic villi, a large number of inflammatory cells and mucosal damage, whereas mice of the group treated with PZ had small intestinal villus morphology and their villi showed signs of recovery from the damage of UC. The results of the present study indicated that PZ significantly alleviates DSS-induced UC in mice, relieves diarrhea, and inhibits the phosphorylation of inflammatory factors and the inflammatory AKT signaling pathway.

Attenuated lipopolysaccharide-induced inflammatory bladder hypersensitivity in mice deficient of transient receptor potential ankilin1

Transient receptor potential ankyrin 1 (TRPA1) channel expressed by urothelial cells and bladder sensory nerve fibers might act as a bladder mechanosensor and nociceptive transducer. To disclose the role of TRPA1 in bladder function and inflammation-associated hypersensitivity, we evaluated in vitro and in vivo bladder function and inflammatory mechanosensory and nociceptive responses to intravesical lipopolysaccharide (LPS)-instillation in wild type (WT) and TRPA1-knock out (KO) mice. At baseline before treatment, no significant differences were observed in frequency volume variables, in vitro detrusor contractility, and cystometric parameters between the two groups in either sex. LPS-instillation significantly increased voiding frequency and decreased mean voided volume at 24-48 hours after instillation in WT but not in TRPA1-KO mice. LPS-instillation also significantly increased the number of pain-like behavior at 24 hours after instillation in WT mice, but not in TRPA1-KO mice. Cystometry 24 hours after LPS-instillation revealed shorter inter-contraction intervals in the WT mice compared with TRPA1-KO mice. In contrast, inflammatory cell infiltration in the bladder suburothelial layer was not significantly different between the two groups. These results indicate that TRPA1 channels are involved in bladder mechanosensory and nociceptive hypersensitivity accompanied with inflammation but not in physiological bladder function or development of bladder inflammation.

Downregulation of tight junction protein zonula occludens-2 and urothelium damage in a cyclophosphamide-induced mouse model of cystitis

OBJECTIVES

The cyclophosphamide (CYP)-induced model of cystitis in mice closely fits the symptoms of chronic bladder inflammation. Cystitis was recently found to be due to an altered gap junction protein in a rat model. Thus, this study was conducted to evaluate changes in protein expression and composition in the bladder of CYP-treated mice.

MATERIALS AND METHODS

Administration of CYP induced cystitis-related symptoms in mice. Cystometry was assessed and cell junction-associated protein zonula occludens-2 (ZO-2) expression was measured. Voiding interval values (time between voids) were assessed in mice under anesthesia. The bladders were removed for proteomic analysis using label-free quantitative proteomics and liquid chromatography-mass spectrometry. Additionally, immunochemistry (IHC) and Western blot were used to confirm the location and level, respectively, of ZO-2 expression.

RESULTS

Compared to the control group, the voiding interval values and urothelial thickness in the bladder in the CYP-treated group were significantly decreased. Additionally, we identified 105 differentially expressed proteins in the bladder of CYP-treated mice with proteomic analysis. These proteins were involved in cell-cell tight junctions, exocytosis, muscle development, contraction, and regulation, immune responses, proteolysis, and cell adhesion. IHC and Western blot confirmed the downregulation of the tight junction protein ZO-2 in the urothelium of bladder.

CONCLUSIONS

Our results suggest that downregulation in tight junction protein ZO-2 and urothelium damage may have a role in cystitis-related OAB. These changes could be related to the molecular mechanism of cystitis-related OAB.

Effects of polaprezinc on gastric mucosal damage and neurotransmitters in a rat model of chemotherapy-induced vomiting

Objective

To investigate the effects of polaprezinc (PZ) on cyclophosphamide (CTX)- or cisplatin (DDP)-induced gastric mucosal injury and on a rat model of neurotransmitter-mediated vomiting.

Methods

Sprague–Dawley rats were divided at random into Control, CTX, DDP, PZ+CTX, and PZ+DDP groups. After 20 days, brain tissues and sera were analyzed for the levels of dopamine (DA), 5-hydroxytryptamine (5-HT), and nuclear factor kappa B (NF-κB). Hematoxylin and eosin-stained sections of stomach, intestine, and brain tissues were examined using light microscopy.

Results

The levels of DA, 5-HT, and NF-κB in brain and serum samples of rats treated with CTX or DDP were significantly increased compared with those of rats in the Control group. There was a significant decrease in these values in the PZ group. Moreover, PZ reduced damage to brain tissue caused by CTX or DDP.

Conclusions

PZ decreased the levels of DA, 5-HT, and NF-κB in blood and brain tissues caused by CTX or DDP and reduced the chemotherapy-induced damage to the small intestine, stomach, and brain. These findings can be translated to the clinic to enhance the efficacy and safety of chemotherapy.

Zinc deficiency promotes cystitis-related bladder pain by enhancing function and expression of Cav3.2 in mice

Ca_v3.2 T-type Ca²⁺ channel activity is suppressed by zinc that binds to the extracellular histidine-191 of Ca_v3.2, and enhanced by H₂S that interacts with zinc. Ca_v3.2 in nociceptors is upregulated in an activity-dependent manner. The enhanced Ca_v3.2 activity by H₂S formed by the upregulated cystathionine-γ-lyase (CSE) is involved in the cyclophosphamide (CPA)-induced cystitis-related bladder pain in mice. We thus asked if zinc deficiency affects the cystitis-related bladder pain in mice by altering Ca_v3.2 function and/or expression. Dietary zinc deficiency for 2 weeks greatly decreased zinc concentrations in the plasma but not bladder tissue, and enhanced the bladder pain/referred hyperalgesia (BP/RH) following CPA at 200mg/kg, a subeffective dose, but not 400mg/kg, a maximal dose, an effect abolished by pharmacological blockade or gene silencing of Ca_v3.2. Acute zinc deficiency caused by systemic N,N,N',N'-tetrakis-(2-pyridylmethyl)-ethylendiamine (TPEN), a zinc chelator, mimicked the dietary zinc deficiency-induced Ca_v3.2-dependent promotion of BP/RH following CPA at 200mg/kg. CPA at 400mg/kg alone or TPEN plus CPA at 200mg/kg caused Ca_v3.2 overexpression accompanied by upregulation of Egr-1 and USP5, known to promote transcriptional expression and reduce proteasomal degradation of Ca_v3.2, respectively, in the dorsal root ganglia (DRG). The CSE inhibitor, β-cyano-l-alanine, prevented the BP/RH and upregulation of Ca_v3.2, Egr-1 and USP5 in DRG following TPEN plus CPA at 200mg/kg. Together, zinc deficiency promotes bladder pain accompanying CPA-induced cystitis by enhancing function and expression of Ca_v3.2 in nociceptors, suggesting a novel therapeutic avenue for treatment of bladder pain, such as zinc supplementation.

Sustained relief of ongoing experimental neuropathic pain by a CRMP2 peptide aptamer with low abuse potential

Uncoupling the protein-protein interaction between collapsin response mediator protein 2 (CRMP2) and N-type voltage-gated calcium channel (CaV2.2) with an allosteric CRMP2-derived peptide (CBD3) is antinociceptive in rodent models of inflammatory and neuropathic pain. We investigated the efficacy, duration of action, abuse potential, and neurobehavioral toxicity of an improved mutant CRMP2 peptide. A homopolyarginine (R9)-conjugated CBD3-A6K (R9-CBD3-A6K) peptide inhibited the CaV2.2-CRMP2 interaction in a concentration-dependent fashion and diminished surface expression of CaV2.2 and depolarization-evoked Ca influx in rat dorsal root ganglia neurons. In vitro studies demonstrated suppression of excitability of small-to-medium diameter dorsal root ganglion and inhibition of subtypes of voltage-gated Ca channels. Sprague-Dawley rats with tibial nerve injury had profound and long-lasting tactile allodynia and ongoing pain. Immediate administration of R9-CBD3-A6K produced enhanced dopamine release from the nucleus accumbens shell selectively in injured animals, consistent with relief of ongoing pain. R9-CBD3-A6K, when administered repeatedly into the central nervous system ventricles of naive rats, did not result in a positive conditioned place preference demonstrating a lack of abusive liability. Continuous subcutaneous infusion of R9-CBD3-A6K over a 24- to 72-hour period reversed tactile allodynia and ongoing pain, demonstrating a lack of tolerance over this time course. Importantly, continuous infusion of R9-CBD3-A6K did not affect motor activity, anxiety, depression, or memory and learning. Collectively, these results validate the potential therapeutic significance of targeting the CaV-CRMP2 axis for treatment of neuropathic pain.

The Physiology, Pathology, and Pharmacology of Voltage-Gated Calcium Channels and Their Future Therapeutic Potential

Voltage-gated calcium channels are required for many key functions in the body. In this review, the different subtypes of voltage-gated calcium channels are described and their physiologic roles and pharmacology are outlined. We describe the current uses of drugs interacting with the different calcium channel subtypes and subunits, as well as specific areas in which there is strong potential for future drug development. Current therapeutic agents include drugs targeting L-type Ca(V)1.2 calcium channels, particularly 1,4-dihydropyridines, which are widely used in the treatment of hypertension. T-type (Ca(V)3) channels are a target of ethosuximide, widely used in absence epilepsy. The auxiliary subunit α2δ-1 is the therapeutic target of the gabapentinoid drugs, which are of value in certain epilepsies and chronic neuropathic pain. The limited use of intrathecal ziconotide, a peptide blocker of N-type (Ca(V)2.2) calcium channels, as a treatment of intractable pain, gives an indication that these channels represent excellent drug targets for various pain conditions. We describe how selectivity for different subtypes of calcium channels (e.g., Ca(V)1.2 and Ca(V)1.3 L-type channels) may be achieved in the future by exploiting differences between channel isoforms in terms of sequence and biophysical properties, variation in splicing in different target tissues, and differences in the properties of the target tissues themselves in terms of membrane potential or firing frequency. Thus, use-dependent blockers of the different isoforms could selectively block calcium channels in particular pathologies, such as nociceptive neurons in pain states or in epileptic brain circuits. Of important future potential are selective Ca(V)1.3 blockers for neuropsychiatric diseases, neuroprotection in Parkinson's disease, and resistant hypertension. In addition, selective or nonselective T-type channel blockers are considered potential therapeutic targets in epilepsy, pain, obesity, sleep, and anxiety. Use-dependent N-type calcium channel blockers are likely to be of therapeutic use in chronic pain conditions. Thus, more selective calcium channel blockers hold promise for therapeutic intervention.