Polaprezinc (Zinc L-carnosine) is a potent inducer of anti-oxidative stress enzyme, heme oxygenase (HO)-1 - a new mechanism of gastric mucosal protection

Zinc Supplementation and an Improved Quality of Life in Patients with Autoimmune Hepatitis

Objecive Patients with autoimmune hepatitis (AIH) reportedly have an impaired quality of life (QOL), mainly due to depression, even during remission. In addition, hypozincaemia has been demonstrated in patients with chronic liver disease, including AIH, and is known to be related to depression. Corticosteroids are known to cause mental instability. We therefore investigated the longitudinal association between zinc supplementation and changes in the mental status among AIH patients treated with corticosteroids. Materials This study enrolled 26 patients with serological remission of AIH routinely treated at our facility after excluding 15 patients who either discontinued polaprezinc (150 mg/day) within 24 months or interrupted treatment. Two questionnaires, the Chronic Liver Disease Questionnaire (CLDQ) and SF-36, were adopted to evaluate the QOL before and after zinc supplementation. Results Serum zinc levels were significantly elevated after zinc supplementation (p<0.0001). The CLDQ worry subscale significantly improved after zinc supplementation (p=0.017), but none of the SF-36 subscales was affected. Multivariate analyses demonstrated that daily prednisolone dosing was inversely related to both the CLDQ worry domain score (p=0.036) and the SF-36 mental health component (p=0.031). There was a significant negative correlation between the changes in the daily steroid dose and the CLDQ worry domain scores before and after zinc supplementation (p=0.006). No serious adverse events occurred during the observation period. Conclusion Zinc supplementation safely and efficiently improved mental impairment, possibly caused by continuous treatment with corticosteroids, in patients with AIH.

A randomised trial of topical polaprezinc to prevent oral mucositis in patients undergoing haematopoietic stem cell transplantation (ToPaZ study)

PURPOSE

Oral mucositis (OM) is a common complication in haematopoietic stem cell transplantation (HSCT). Polaprezinc, an anti-ulcer drug, has been shown to be effective to prevent OM in several studies when administered topically and systemically. This study aimed to evaluate the effectiveness of topical polaprezinc in patients undergoing HSCT.

METHODS

This was an open-label randomised clinical trial comparing polaprezinc and sodium bicarbonate mouthwashes for the prevention of severe OM in HSCT patients. Adult patients who received conditioning regimens at moderate to high risk of developing OM were included. The primary endpoint was the incidence of severe (WHO grades 3-4) OM. The secondary endpoints included duration of grades 3-4 OM, incidence and duration of grades 2-4 OM, patient-reported pain and functional limitations.

RESULTS

In total, 108 patients (55 test arm and 53 control arm) were randomised. There was no difference in the incidence of grades 3 to 4 OM (35% test arm versus 36% control arm). The secondary endpoints were not significantly different. In both arms, patients reported more throat pain compared to mouth pain.

CONCLUSIONS

Topical polaprezinc had no effect in the prevention of OM in HSCT patients. Further research is required to evaluate the effects of systemic polaprezinc. The OM assessment tool needs to be reviewed as throat mucositis was a main issue in this study.

TRIAL REGISTRATION

ACTRN12320001188921 (Date Registered: 10th November 2020).

Therapeutic Effect of Polaprezinc on Reflux Esophagitis in the Rat Model

BACKGROUND/AIMS

To explore the protective effects and therapeutic mechanism of Esomeprazole (PPI), polaprezinc granule (PZ), and PPI + PZ on reflux esophagitis (RE) in the rat model.

METHODS

Wistar rats were randomly divided into 9 groups, which contain the control group, the acid cessation group (0.7% HCl, Q3D × 4), and the acid persistence group (0.7% HCl, Q3D × 11). PPI was administered by gavage at 8 mg·kg^-1 body weight and PZ was administered by gavage at 120 mg·kg^-1 body weight once a day for 15 days. The gastric cardia tissue of the feeding tube was observed under the light microscope, and the levels of interleukin-8 (IL-8) and prostaglandin E2 (PGE2) were measured by ELISA. The expression of EGFR, Akt, p-Akt, and p-mTOR was detected by Western blot.

RESULTS

The ELISA results showed that the levels of IL-8 and PGE2 were significantly increased in the model group, but decreased in all groups after treatment. In the acid cessation group, PZ treatment had the most significant effect on reducing IL-8 levels and PPI + PZ treatment had the most significant effect on reducing PGE2 levels. In the acid persistence group, the PPI treatment had the most significant effect on reducing the levels of IL-8 and PGE2, and the PZ treatment could also significantly reduce their levels, close to the normal value. Western blot results showed that the expression of PI3K/Akt/mTOR pathway protein was increased in the model group, while its expression was decreased after treatment.

CONCLUSIONS

Polaprezinc has a significant therapeutic effect on RE in rats, which can reduce the levels of IL-8 and PGE2 and downregulate the expression of PI3K/Akt/mTOR signal pathway protein. The efficacy of polaprezinc in the treatment of reflux esophagitis is comparable to that of PPI, and the combination of them is more effective in the reflux esophagitis treatment.

Periodontal Health and Disease in the Context of Systemic Diseases

During recent years, considerable progress has been made in understanding the etiopathogenesis of periodontitis in its various forms and their interactions with the host. Furthermore, a number of reports have highlighted the importance of oral health and disease in systemic conditions, especially cardiovascular diseases and diabetes. In this regard, research has attempted to explain the role of periodontitis in promoting alteration in distant sites and organs. Recently, DNA sequencing studies have revealed how oral infections can occur in distant sites such as the colon, reproductive tissues, metabolic diseases, and atheromas. The objective of this review is to describe and update the emerging evidence and knowledge regarding the association between periodontitis and systemic disease and to analyse the evidence that has reported periodontitis as a risk factor for the development of various forms of systemic diseases in order to provide a better understanding of the possible shared etiopathogenetic pathways between periodontitis and the different forms of systemic diseases.

Mucosal Overexpression of Thymic Stromal Lymphopoietin and Proinflammatory Cytokines in Patients With Autoimmune Atrophic Gastritis

INTRODUCTION

The immune mechanisms underlying human autoimmune atrophic gastritis (AAG) are poorly understood. We sought to assess immune mucosal alterations in patients with AAG.

METHODS

In 2017-2021, we collected gastric corpus biopsies from 24 patients with AAG (median age 62 years, interquartile range 56-67, 14 women), 26 age-matched and sex-matched healthy controls (HCs), and 14 patients with Helicobacter pylori infection (HP). We investigated the lamina propria mononuclear cell (LPMC) populations and the mucosal expression of thymic stromal lymphopoietin (TSLP) and nicotinamide phosphoribosyltransferase (NAMPT). Ex vivo cytokine production by organ culture biopsies, under different stimuli (short TSLP and zinc-l-carnosine), and the gastric vascular barrier through plasmalemma vesicle-associated protein-1 (PV1) were also assessed.

RESULTS

In the subset of CD19+ LPMC, CD38+ cells (plasma cells) were significantly higher in AAG compared with HC. Ex vivo production of tumor necrosis factor (TNF)-α, interleukin (IL)-15, and transforming growth factor β1 was significantly higher in AAG compared with HC. At immunofluorescence, both IL-7R and TSLP were more expressed in AAG compared with HC and HP, and short TSLP transcripts were significantly increased in AAG compared with HC. In the supernatants of AAG corpus mucosa, short TSLP significantly reduced TNF-α, while zinc-l-carnosine significantly reduced interferon-γ, TNF-α, IL-21, IL-6, and IL-15. NAMPT transcripts were significantly increased in AAG compared with HC. PV1 was almost absent in AAG, mildly expressed in HC, and overexpressed in HP.

DISCUSSION

Plasma cells, proinflammatory cytokines, and altered gastric vascular barrier may play a major role in AAG. TSLP and NAMPT may represent potential therapeutic targets, while zinc-l-carnosine may dampen mucosal inflammation.

Omeprazole Increases Survival Through the Inhibition of Inflammatory Mediaters in Two Rat Sepsis Models

BACKGROUND

Omeprazole (OMZ) is a proton pump inhibitor that is used to reduce gastric acid secretion, but little is known about its possible liver protective effects. This study investigated whether OMZ has beneficial effects in rat septic models of LPS-induced liver injury after D-galactosamine (GalN) treatment and 70% hepatectomy (PH), and to determine the mechanisms of OMZ in an in vitro model of liver injury.

METHODS

In the in vivo models, the effects of OMZ were examined 1 h before treatments in both models on survival, nuclear factor (NF)-κB activation, histopathological analysis, and proinflammatory mediator expression in the liver and serum. In the in vitro model, primary cultured rat hepatocytes were treated with IL-1β in the presence or absence of OMZ. The influence of OMZ on nitric oxide (NO) product and inducible NO synthase (iNOS) induction and on the associated signaling pathway was analyzed.

RESULTS

OMZ increased survival and decreased tumor necrosis factor-alpha, iNOS, cytokine-induced neutrophil chemoattractant 1, IL-6, and IL-1β mRNA expression, and increased IL-10 mRNA expression in the livers of both GaIN/LPS- and PH/LPS-treated rats. Necrosis and apoptosis were inhibited by OMZ in GaIN/LPS rats, but OMZ had no effects on necrosis in PH/LPS rats. OMZ inhibited iNOS induction partially through suppression of NF-κB signaling in hepatocytes.

CONCLUSIONS

OMZ inhibited the induction of several inflammatory mediators, resulting in the prevention of LPS-induced liver injury after GalN liver failure and PH, although OMZ showed different doses and mechanisms in the two models.

Recent advances on polaprezinc for medical use (Review)

The present study described the chemical and biological properties of zinc complex of L-carnosine (L-CAZ; generic name, polaprezinc; chemical name, catena-(S)-[µ-[N(α)-(3-aminopropionyl) histidinato (2-) N1, N2, O: N(τ)]-zinc], molecular formula, C₉H₁₄N₄O₃Zn; molecular weight, 291.6404; CAS registry number, 107667-60-7). Characterized as a white or yellowish white crystalline powder, this drug is insoluble in glacial acetic acid and almost insoluble in water, methanol, ethanol and ether. It is soluble in dilute hydrochloric acid, dilute nitric acid and sodium hydroxide solution, and its melting point is 260-270˚C. Polaprezinc is an anti-ulcer drug that was jointly studied and developed by Hamari Chemicals Co., Ltd. and Zeria Pharmaceutical Co., Ltd., and was first approved in Japan in 1994. This review article summarizes the research advances of polaprezinc, including the patents, preparations, synthetic routes, pharmacokinetics, pharmacological effects and application in clinical research.

The Role of Gasotransmitters in Gut Peptide Actions

Although gasotransmitters nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H₂S) receive a bad connotation; in low concentrations these play a major governing role in local and systemic blood flow, stomach acid release, smooth muscles relaxations, anti-inflammatory behavior, protective effect and more. Many of these physiological processes are upstream regulated by gut peptides, for instance gastrin, cholecystokinin, secretin, motilin, ghrelin, glucagon-like peptide 1 and 2. The relationship between gasotransmitters and gut hormones is poorly understood. In this review, we discuss the role of NO, CO and H₂S on gut peptide release and functioning, and whether manipulation by gasotransmitter substrates or specific blockers leads to physiological alterations.

A Computational-Based Drug Repurposing Method Targeting SARS-CoV-2 and its Neurological Manifestations Genes and Signaling Pathways

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as a global concern involves infections in multiple organs. Much of the research up to now has been descriptive on neurological manifestations followed by SARS-CoV-2 infection. Despite considerable efforts on effective SARS-CoV-2 vaccine, novel therapeutic options for COVID-19 comorbidities are warranted. One of the fast ways to introduce possible effective drugs for clinical trials is bioinformatics methods. We have conducted a comprehensive enrichment analysis of genes involved in SARS-CoV-2 and neurological disorders associated with COVID-19. For this purpose, gene sets were extracted from the GeneWeaver database. To find out some significant enriched findings for common genes between SARS-CoV-2 and its neurological disorders, several practical databases were used. Finally, to repurpose an efficient drug, DrugBank databases were used. Overall, we detected 139 common genes concerning SARS-CoV-2 and their neurological disorders. Interestingly, our study predicted around 6 existing drugs (ie, carvedilol, andrographolide, 2-methoxyestradiol, etanercept, polaprezinc, and arsenic trioxide) that can be used for repurposing. We found that polaprezinc (zinc l-carnosine) drug is not investigated in the context of COVID-19 till now and it could be used for the treatment of COVID-19 and its neurological manifestations. To summarize, enrichment and network data get us a coherent picture to predict drug repurposing to speed up clinical trials.

Oral management with polaprezinc solution reduces adverse events in haematopoietic stem cell transplantation patients

The aim of this study was to analyse the effects of gargling with and then swallowing PPAA (polaprezinc in polyacrylic acid solution), in addition to regular oral management, on patients with a haematopoietic neoplasm scheduled for haematopoietic stem cell transplantation (HSCT). A total of 120 patients scheduled for HSCT during the years 2006-2016 were recruited. Patient background, oral adverse events, the incidence and severity of systemic adverse events (sepsis/septic shock, acute graft-versus-host disease (GVHD) after transplantation), and outcomes (survival/death) were compared between groups treated with and without PPAA. The severities of oral adverse events (oral mucositis, oral pain, and dysgeusia) were significantly lower in patients treated with PPAA. There was no significant difference in the incidence of febrile neutropenia (P=0.622) or sepsis/septic shock (P=0.665) as systemic adverse events. The severity of allograft-induced acute graft-versus-host disease (GVHD) was significantly lower in the PPAA group (P=0.011). There was no significant difference in outcome between the two groups (P=0.285). Within the limitations of the study design, it may be concluded that oral management with PPAA reduces adverse events in HSCT. Oral management with concomitant use of PPAA decreased oral adverse events and reduced the systemic complication of GVHD.

Polaprezinc for prevention of oral mucositis in patients receiving chemotherapy followed by hematopoietic stem cell transplantation: A multi-institutional randomized controlled trial

Oral mucositis is a common and distressing complication in patients receiving high-dose chemotherapy followed by hematopoietic stem cell transplantation (HSCT). We reported previously in a single-center retrospective analysis that zinc-L-carnosine (polaprezinc [PZ]) reduced the incidence of oral mucositis associated with HSCT. To verify the accuracy of the prophylactic effect of PZ against oral mucositis, we carried out a multi-institutional prospective randomized controlled study. Patients were randomly allocated to either the prevention group, in which PZ lozenge treatment was started before chemotherapy, or the control group, in which administration of PZ lozenges was initiated immediately after the onset of Grade 2 oral mucositis. Oral mucositis was evaluated daily from the start of chemotherapy to 35 days after transplantation. A total of 91 patients were enrolled, and 88 patients (47 in the control group and 41 in the prevention group) were eligible for data analysis. The incidence of Grade ≥2 but not Grade ≥3 oral mucositis was significantly reduced in the prevention group compared to the control group (44.7% in control group vs 22.0% in the prevention group, P = .025). There were no significant differences in the incidence rates of other adverse events or the rate of engraftment (95.6% vs 97.2%, P = .693) between the two groups. These findings suggest that PZ lozenge is effective for prophylaxis against Grade ≥2 oral mucositis associated with chemotherapy in patients undergoing HSCT without any influence on the HSCT outcome.

A Review of Zinc-L-Carnosine and Its Positive Effects on Oral Mucositis, Taste Disorders, and Gastrointestinal Disorders

Zinc-L-carnosine (ZnC), also called polaprezinc known as PepZin GI™, is a chelated compound that contains L-carnosine and zinc. It is a relatively new molecule and has been associated with multiple health benefits. There are several studies that support ZnC’s benefits in restoring the gastric lining, healing other parts of the gastrointestinal (GI) tract, improving taste disorders, improving GI disorders, and enhancing skin and liver. Oral mucositis is a common complication of cytotoxic radiotherapy and/or chemotherapy. It occurs in almost every person with head and neck cancer who receive radiotherapy. It is often overlooked because it is not considered life threatening. However, mucositis often leads to a decreased quality of life and cessation of treatment, ultimately decreasing positive outcomes. Therefore, solutions to address it should be considered. The primary mechanisms of action are thought to be localized and related to ZnC’s anti-inflammatory and antioxidant functions. Therefore, the purpose of this review is to discuss the research related to ZnC and to explore its benefits, especially in the management of conditions related to damaged epithelial cells, such as oral mucositis. Evidence supports the safety and efficacy of ZnC for the maintenance, prevention, and treatment of the mucosal lining and other epithelial tissues. The research supports its use for gastric ulcers (approved in Japan) and conditions of the upper GI and suggests other applications, particularly for oral mucositis.

A new derivative of acetylsalicylic acid and carnosine: synthesis, physical and chemical properties, biological activity

PURPOSE

The aim of this study was to create and assess biological activity of a new compound based on carnosine and acetylsalicylic acid (ASA) that will comprise antioxidant effect with antiplatelet activity, while simultaneously preventing side effects on the gastrointestinal tract.

METHODS

Salicyl-carnosine (SC) was synthesized by condensation of ASA and carnosine. Antioxidant activity was determined by spectrophotometric and chemiluminescence methods. Antiplatelet activity was carried out by the light transmission-aggregometry method using the inductor ADP. Chronic gastric ulcer in rats was modeled using glacial acetic acid.

RESULTS

Using SOD-like activity, iron-induced chemiluminescence, BaSO4-activated respiratory burst, and evaluation of red blood cell structure stabilization during oxidative damage induced by sodium hypochlorite, it was shown that SC possesses antioxidant activity analogous, or better, than that of carnosine. Antiplatelet activity of SC was evaluated in the blood of healthy individuals, and was also shown to be comparable to, or exceeding that of ASA. Also SC demonstrates high resistance to hydrolysis by tissue and serum carnosinases. Most importantly, it was shown that SC has protected the gastric mucosa against the formation of stomach ulcerative lesions and promoted their epithelization, therefore overcoming the undesirable inherent side effects of ASA.

CONCLUSIONS

SC preserves pharmacologically significant properties of ASA and carnosine while retaining an anti-ulcer activity and resistance to the carnosinase hydrolysis at the same time. These properties are particularly promising for the potential development of new anti-inflammatory and antithrombotic drugs. Graphical abstract .

The Proton Pump Inhibitor Lansoprazole Has Hepatoprotective Effects in In Vitro and In Vivo Rat Models of Acute Liver Injury

BACKGROUND/AIMS

The proton pump inhibitor lansoprazole (LPZ) is clinically used to reduce gastric acid secretion, but little is known about its possible hepatoprotective effects. This study aimed to investigate the hepatoprotective effects of LPZ and its potential mechanisms using in vitro and in vivo rat models of liver injury.

METHODS

For the in vitro model of liver injury, primary cultured rat hepatocytes were treated with interleukin-1β in the presence or absence of LPZ. The influence of LPZ on inducible nitric oxide synthase (iNOS) induction and nitric oxide (NO) production and on the associated signaling pathways was analyzed. For the in vivo model, rats were treated with D-galactosamine (GalN) and lipopolysaccharide (LPS). The effects of LPZ on survival and proinflammatory mediator expression (including iNOS and tumor necrosis factor-α) in these rats were examined.

RESULTS

LPZ inhibited iNOS induction partially through suppression of the nuclear factor-kappa B signaling pathway in hepatocytes, thereby reducing potential liver injury from excessive NO levels. Additionally, LPZ increased survival by 50% and decreased iNOS, tumor necrosis factor-α, and cytokine-induced neutrophil chemoattractant-1 mRNA expression in the livers of GalN/LPS-treated rats. LPZ also inhibited nuclear factor-kappa B activation by GalN/LPS.

CONCLUSIONS

LPZ inhibits the induction of several inflammatory mediators (including cytokines, chemokines, and NO) partially through suppression of nuclear factor-kappa B, resulting in the prevention of fulminant liver failure. The therapeutic potential of LPZ for liver injuries warrants further investigation.

Prodigiosins from a marine sponge-associated actinomycete attenuate HCl/ethanol-induced gastric lesion via antioxidant and anti-inflammatory mechanisms

Gastric ulcer is sores that form in the stomach mucosal layer because of erosion caused by high acid secretion and excessive use of non-steroidal anti-inflammatory drugs. Prodigiosins (PdGs) are red-pigmented secondary metabolites produced by bacteria, including actinomycetes. Butylcycloheptylprodigiosin (1) and undecylprodigiosin (2) were identified and isolated from a crude extract of the actinomycete RA2 isolated from the Red Sea Sponge Spheciospongia mastoidea. Chemical structure of 1 and 2 was determined by NMR and mass spectroscopy. Although their antioxidant and anti-inflammatory properties are known, their effect on gastric lesion is unknown. Therefore, this study aimed to investigate gastroprotective effects of PdGs against HCl/ethanol-induced gastric lesion in rats. Oral pretreatment with PdGs (100, 200, and 300 mg/kg) attenuated severity of HCl/ethanol-induced gastric mucosal injury, as evidenced by decreases in gastric lesion index scores, ulceration area, histopathologic abnormality, and neutrophil infiltration. These effects were comparable to those of omeprazole, a standard anti-gastric ulcer agent. HCl/ethanol-induced gastric erosions was associated with tremendous increases in lipid peroxidation, nitric oxide, and pro-inflammatory cytokines and mediators (myeloperoxidase, interleukin-1β, tumor necrosis factor-α, and cyclooxygenase-2), and with significant decreases in enzymatic and non-enzymatic antioxidant activities. However, PdGs ameliorated gastric inflammation and oxidative stress by downregulating nuclear factor kappa B and inducible nitric oxide synthase expression and upregulating heme oxygenase-1 expression. PdGs prevented gastric mucosal apoptosis by downregulating Bax and caspase-3 expression and upregulating Bcl-2 expression, thereby increasing prostaglandin E2 production. Our results suggested that PdGs exerted gastroprotective effects by decreasing the levels of inflammatory mediators, apoptotic markers, and antioxidants.

In Vitro and In Vivo Neuroprotective Effects of Stellettin B Through Anti-Apoptosis and the Nrf2/HO-1 Pathway

Pharmaceutical agents for halting the progression of Parkinson’s disease (PD) are lacking. The current available medications only relieve clinical symptoms and may cause severe side effects. Therefore, there is an urgent need for novel drug candidates for PD. In this study, we demonstrated the neuroprotective activity of stellettin B (SB), a compound isolated from marine sponges. We showed that SB could significantly protect SH-SY5Y cells against 6-OHDA-induced cellular damage by inhibiting cell apoptosis and oxidative stress through PI3K/Akt, MAPK, caspase cascade modulation and Nrf2/HO-1 cascade modulation, respectively. In addition, an in vivo study showed that SB reversed 6-OHDA-induced a locomotor deficit in a zebrafish model of PD. The potential for developing SB as a candidate drug for PD treatment is discussed.

Utility of polaprezinc in reducing toxicities during radiotherapy: a literature review

Chemoradiotherapy is important for treating malignancies. However, radiation-induced toxicities develop as chemoradiotherapy-related complications. Various agents reduce or prevent toxicities, but there are no standard treatments. Polaprezinc (PZ), a chelating compound used for gastric ulcers, has antioxidant and free radical scavenging effects. Although few studies have evaluated PZ and radiation-induced normal tissue damage, several clinical studies have shown the efficacy of PZ for oral mucositis, esophagitis, proctitis and taste alterations during and after radiotherapy. Moreover, preclinical data support the clinical data, indicating good potential of testing PZ in future trials. However, as there are only few well-documented review articles on PZ use in cancer treatment, we conducted this literature review. PZ reduced several radiation-induced toxicities and improved the quality of life.

Evaluation of anti-inflammatory and ulcerogenic potential of zinc-ibuprofen and zinc-naproxen complexes in rats

Because of numerous indications and high availability, non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly prescribed and used medicines in the world. However, long-term therapy with and improper use of NSAIDs may lead to gastrointestinal damage. Therefore, improving the therapeutic index of the existing drugs has become a priority over the past decades. Considerable attention in the field has been concentrated on metal complexes of non-steroidal anti-inflammatory drugs. The aim of this study is to evaluate the effect of complexation with zinc on the anti-inflammatory and ulcerogenic effects of ibuprofen and naproxen after single and triple intragastric administration to rats. The anti-inflammatory effect was assessed in carrageenan-induced inflammatory edema in the hind paw of male albino Wistar rats. The mucosal lesions were inspected and evaluated for gross pathology. Single administration of both the investigated complexes, namely zinc-ibuprofen and zinc-naproxen (20 mg/kg equivalent to ibuprofen and naproxen, respectively) and their parent drugs and physical mixtures with zinc hydroaspartate (ZHA doses: 16.05 and 14.37 mg/kg), caused a significant reduction of the edema after the same time from the carrageenan injection in comparison to the control groups. However, no statistically significant differences between the investigated drugs were observed after their single administration. The mean ulceration score for the mixture of ibuprofen and ZHA was statistically lower than the mean score achieved in rats after treatment with ibuprofen alone. On the other hand, triple intragastric administration of the ZHA-ibuprofen and ZHA-naproxen combination showed substantial enhancement of the anti-inflammatory activity against control groups, as well as against the parent NSAIDs. The most potent anti-inflammatory activity was demonstrated after 2 h from the carrageenan injection in animals receiving ZHA together with naproxen. The edema growth was reduced in these animals by 80.9% as compared to the control group. This result was significantly higher than the results achieved in animals receiving zinc-naproxen (50.2%) or naproxen alone (47.9%). Both NSAID complexes with zinc and mixtures with ZHA alleviated ulcerations caused by parent NSAIDs; however, the mixtures of both ibuprofen and naproxen with ZHA after triple administration were the least damaging. In view of the above results, zinc supplementation during NSAID therapy may have a beneficial effect on ulcer prevention and healing by reducing the effective dose of the parent drug and increasing its potency.

The 1-Tosylpentan-3-one Protects against 6-Hydroxydopamine-Induced Neurotoxicity

Previous studies have demonstrated that the marine compound austrasulfone, isolated from the soft coral Cladiella australis, exerts a neuroprotective effect. The intermediate product in the synthesis of austrasulfone, dihydroaustrasulfone alcohol, attenuates several inflammatory responses. The present study uses in vitro and in vivo methods to investigate the neuroprotective effect of dihydroaustrasulfone alcohol-modified 1-tosylpentan-3-one (1T3O). Results from in vitro experiments show that 1T3O effectively inhibits 6-hydroxydopamine-induced (6-OHDA-induced) activation of both p38 mitogen-activated protein kinase (MAPK) and caspase-3 in SH-SY5Y cells; and enhances nuclear factor erythroid 2–related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expression via phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling. Hoechst staining and Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining results reveal that 1T3O significantly inhibits 6-OHDA-induced apoptosis. In addition, the addition of an Akt or HO-1 inhibitor decreases the protective effect of 1T3O. Thus, we hypothesize that the anti-apoptotic activity of 1T3O in neuronal cells is mediated through the regulation of the Akt and HO-1 signaling pathways. In vivo experiments show that 1T3O can reverse 6-OHDA-induced reduction in locomotor behavior ability in zebrafish larvae, and inhibit 6-OHDA-induced tumor necrosis factor-alpha (TNF-α) increase at the same time. According to our in vitro and in vivo results, we consider that 1T3O exerts its anti-apoptotic activities at SH-SY5Y cells after 6-OHDA challenges, probably via the regulation of anti-oxidative signaling pathways. Therefore, this compound may be a promising therapeutic agent for neurodegenerations.

Antioxidant, Anti-inflammatory, and Genomic Stability Enhancement Effects of Zinc l-carnosine: A Potential Cancer Chemopreventive Agent?

Cancer is one of the major causes of death worldwide, and the incidence and mortality rates of cancer are expected to rise tremendously in the near future. Despite a better understanding of cancer biology and advancement in cancer management, current strategies in cancer treatment remain costly and ineffective. Hence, instead of putting more efforts to search for new cancer cures, attention has now been shifted to the development of cancer chemopreventive agents as a preventive measure for cancer formation. It is well known that neoplastic transformation of cells is multifactorial, and the occurrence of oxidative stress, chronic inflammation, and genomic instability events has been implicated in the carcinogenesis of cells. Zinc l-carnosine (ZnC), which is clinically used as gastric ulcer treatment in Japan, has been suggested to have the potential in preventing cancer development. Multiple studies have revealed that ZnC possesses potent antioxidant, anti-inflammatory, and genomic stability enhancement effects. Thus, this review provides some mechanistic insight into the antioxidant, anti-inflammatory, and genomic stability enhancement effects of ZnC in relevance to its chemopreventive potential.

Preparation and clinical evaluation of a novel lozenge containing polaprezinc, a zinc-L-carnosine, for prevention of oral mucositis in patients with hematological cancer who received high-dose chemotherapy

We previously reported that oral ingestion of polaprezinc, a zinc-L-carnosine, suspended in sodium alginate solution prevents oral mucositis in patients receiving radiotherapy or high-dose chemotherapy. In the present study, we developed a novel preparation of polaprezinc and evaluated clinical effect of the lozenge preparation in patients receiving high-dose chemotherapy for hematopoietic stem cell transplantation. The preparation contained 18.75 mg polaprezinc in a tablet and showed an excellent uniformity and stability up to 24 weeks after storage under room temperature. The incidence rate of grade ≥ 2 oral mucositis was 74 % in patients without premedication, whereas the rate was remarkably reduced in patients receiving the suspension (23 %) or lozenge (13 %) of polaprezinc (P < 0.01). The use of non-opioid analgesic drugs such as anti-inflammatory agents and local anesthetics for oral pain was also greatly reduced by polaprezinc suspension or its lozenge (16 % for suspension and 13 % for lozenge compared with 89 % with no premedication, P < 0.01). These findings suggest that polaprezinc lozenge is simple to apply and highly effective for prevention of oral mucositis associated with high-dose chemotherapy for hematopoietic stem cell transplantation.

Proton pump inhibitor alone vs proton pump inhibitor plus mucosal protective agents for endoscopic submucosal dissection-induced ulcer: a systematic review and meta-analysis

Mucosal protective agents may improve healing of patients with endoscopic submucosal dissection-induced ulcers. The present study systematically evaluated published clinical trials to determine whether combined therapeutic use of mucosal protective agents and proton pump inhibitors can improve the outcome of patients with endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitors alone. PubMed, the Cochrane Library, and the Igaku-Chuo-Zasshi database were searched to identify eligible randomized trials for systematic review. We identified 11 randomized trials for inclusion in our study (1,160 patients). Pooled endoscopic submucosal dissection-induced ulcer healing rates were 45.8% and 34.4% for patients with or without mucosal protective agents, respectively. The odds ratio was 2.28 (95% confidence interval, 1.57-3.31) with no significant study heterogeneity. In conclusion, the systematic review and meta-analysis showed that the combined therapeutic use of proton pump inhibitors and mucosal protective agents improved healing rates of endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitor monotherapy.

Protective role of hemeoxygenase-1 in gastrointestinal diseases

Disorders and diseases of the gastrointestinal system encompass a wide array of pathogenic mechanisms as a result of genetic, infectious, neoplastic, and inflammatory conditions. Inflammatory diseases in general are rising in incidence and are emerging clinical problems in gastroenterology and hepatology. Hemeoxygenase-1 (HO-1) is a stress-inducible enzyme that has been shown to confer protection in various organ-system models. Its downstream effectors, carbon monoxide and biliverdin have also been shown to offer these beneficial effects. Many studies suggest that induction of HO-1 expression in gastrointestinal tissues and cells plays a critical role in cytoprotection and resolving inflammation as well as tissue injury. In this review, we examine the protective role of HO-1 and its downstream effectors in modulating inflammatory diseases of the upper (esophagus and stomach) and lower (small and large intestine) gastrointestinal tract, the liver, and the pancreas. Cytoprotective, anti-inflammatory, anti-proliferative, antioxidant, and anti-apoptotic activities of HO-1 make it a promising if not ideal therapeutic target for inflammatory diseases of the gastrointestinal system.

Proton pump inhibitor alone vs proton pump inhibitor plus mucosal protective agents for endoscopic submucosal dissection-induced ulcer: a systematic review and meta-analysis

Mucosal protective agents may improve healing of patients with endoscopic submucosal dissection-induced ulcers. The present study systematically evaluated published clinical trials to determine whether combined therapeutic use of mucosal protective agents and proton pump inhibitors can improve the outcome of patients with endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitors alone. PubMed, the Cochrane Library, and the Igaku-Chuo-Zasshi database were searched to identify eligible randomized trials for systematic review. We identified 11 randomized trials for inclusion in our study (1,160 patients). Pooled endoscopic submucosal dissection-induced ulcer healing rates were 45.8% and 34.4% for patients with or without mucosal protective agents, respectively. The odds ratio was 2.28 (95% confidence interval, 1.57–3.31) with no significant study heterogeneity. In conclusion, the systematic review and meta-analysis showed that the combined therapeutic use of proton pump inhibitors and mucosal protective agents improved healing rates of endoscopic submucosal dissection-induced ulcers compared to treatment with proton pump inhibitor monotherapy.

Zinc carnosine protects against hydrogen peroxide-induced DNA damage in WIL2-NS lymphoblastoid cell line independent of poly (ADP-Ribose) polymerase expression

The aim of this study is to investigate the ability of zinc carnosine to protect the human lymphoblastoid (WIL2-NS) cell line from hydrogen peroxide-induced DNA damage. Cells were cultured with medium containing zinc carnosine at the concentrations of 0.4, 4, 16 and 32 μM for 9 days prior to treatment with 30 μM of hydrogen peroxide (30 min). Zinc carnosine at the concentration 16 μM was optimal in protecting cells from hydrogen peroxide-induced cytotoxicity and gave the lowest percentage of apoptotic and necrotic cells. Results showed that zinc carnosine was able to induce glutathione production and protect cells from hydrogen peroxide-induced oxidative stress at all concentration and the highest protection was observed at 32-μM zinc carnosine culture. Cytokinesis-block micronucleus cytome assay showed that cells cultured with 4-32 μM of zinc carnosine showed significant reduction in micronuclei formation, nucleoplasmic bridges and nuclear bud frequencies (p < 0.05), suggesting that these concentrations maybe optimal in protecting cells from hydrogen peroxide-induced DNA damage. However, after being challenged with hydrogen peroxide, no increase in poly(ADP-ribose) polymerase expression was observed. Thus, results from this study demonstrate that zinc carnosines possess antioxidant properties and are able to reduce hydrogen peroxide-induced DNA damage in vitro independent of poly(ADP-ribose) polymerase. Further studies are warranted to understand the mechanism of protection of zinc carnosine against hydrogen peroxide-induced damage.

Nrf2-inducing anti-oxidation stress response in the rat liver--new beneficial effect of lansoprazole

Lansoprazole is a potent anti-gastric ulcer drug that inhibits gastric proton pump activity. We identified a novel function for lansoprazole, as an inducer of anti-oxidative stress responses in the liver. Gastric administration of lansoprazole (10–100 mg/kg) to male Wistar rats produced a dose-dependent increase in hepatic mRNA levels of nuclear factor, erythroid-derived 2, -like 2 (Nrf2), a redox-sensitive transcription factor, at 3 h and Nrf2 immunoreactivity (IR) in whole hepatic lysates at 6 h. Conversely, the levels of Kelch-like ECH-associated protein (Keap1), which sequesters Nrf2 in the cytoplasm under un-stimulated conditions, were unchanged. Translocation of Nrf2 into the nuclei of hepatocytes was observed using western blotting and immunohistochemistry. Expression of mRNAs for Nrf2-dependent antioxidant and phase II enzymes, such as heme oxygenase 1 (HO-1), NAD (P) H dehydrogenase, quinone 1 (Nqo1), glutathione S-transferase A2 (Gsta2), UDP glucuronosyltransferase 1 family polypeptide A6 (Ugt1a6), were dose-dependently up-regulated at 3 h. Furthermore, the levels of HO-1 IR were dose-dependently increased in hepatocytes at 6 h. Subcutaneous administration of lansoprazole (30 mg/kg/day) for 7 successive days resulted in up-regulation and nuclear translocation of Nrf2 IR in hepatocytes and up-regulation of HO-1 IR in the liver. Pretreatment with lansoprazole attenuated thioacetamide (500 mg/kg)-induced acute hepatic damage via both HO-1-dependent and -independent pathways. Up-stream networks related to Nrf2 expression were investigated using microarray analysis, followed by data mining with Ingenuity Pathway Analysis. Up-regulation of the aryl hydrocarbon receptor (AhR)-cytochrome P450, family 1, subfamily a, polypeptide 1 (Cyp1a1) pathway was associated with up-regulation of Nrf2 mRNA. In conclusion, lansoprazole might have an alternative indication in the prevention and treatment of oxidative hepatic damage through the induction of both phase I and phase II drug-metabolizing systems, i.e. the AhR/Cyp1a1/Nrf2 pathway in hepatocytes.

Carnosinases, their substrates and diseases

Carnosinases are Xaa-His dipeptidases that play diverse functions throughout all kingdoms of life. Human isoforms of carnosinase (CN1 and CN2) under appropriate conditions catalyze the hydrolysis of the dipeptides carnosine (β-alanyl-l-histidine) and homocarnosine (γ-aminobutyryl-l-histidine). Alterations of serum carnosinase (CN1) activity has been associated with several pathological conditions, such as neurological disorders, chronic diseases and cancer. For this reason the use of carnosinase levels as a biomarker in cerebrospinal fluid (CSF) has been questioned. The hydrolysis of imidazole-related dipeptides in prokaryotes and eukaryotes is also catalyzed by aminoacyl-histidine dipeptidases like PepD (EC 3.4.13.3), PepV (EC 3.4.13.19) and anserinase (EC 3.4.13.5). The review deals with the structure and function of this class of enzymes in physiological and pathological conditions. The main substrates of these enzymes, i.e., carnosine, homocarnosine and anserine (β-alanyl-3-methyl-l-histidine) will also be described.

The effect of polaprezinc on gastric mucosal protection in rats with ethanol-induced gastric mucosal damage: comparison study with rebamipide

AIMS

Polaprezinc (PZ), which consists of l-carnosine and zinc, is widely used to treat gastric ulcers. We compared the effects of PZ with those of rebamipide (RM) on the expression of inflammatory cytokines, antioxidants, growth factors, and heat shock proteins (HSP) in a rat model.

MAIN METHODS

Seventy Sprague-Dawley rats were randomly assigned to test groups according to the dose of PZ at 5, 10, or 30 mg/kg or RM at 10, 30, or 100 mg/kg. Next, we obtained ulcer indices from rats with ethanol-induced gastric mucosal damage. Western blot analysis was used to evaluate the expression of various target proteins.

KEY FINDINGS

Pathological ulcer indices in the PZ and RM groups were significantly lower than those in the control group. The levels of inflammatory cytokines (interleukin 1β [IL-1β], IL-6, IL-8, and tumor necrosis factor α) decreased, whereas the levels of platelet-derived growth factor-B, vascular endothelial growth factor, and nerve growth factor significantly increased after PZ administration. Furthermore, the expression of antioxidants (superoxide dismutase 1 [SOD-1], SOD-2, heme oxygenase-1, glutathione S-transferase, peroxidredoxin-1, and peroxidredoxin-5) was significantly higher in the PZ group, and the levels of HSP 90, 70, 60, 47, 27, and 10 significantly increased with an increase in PZ dose.

SIGNIFICANCE

In a rat model of ethanol-induced gastric mucosal damage, PZ administration ameliorated ethanol-induced mucosal injury and showed protective effects on the mucosa by reducing the levels of inflammatory cytokines and increasing the expression of antioxidant enzymes and growth factors. Furthermore, PZ showed cytoprotective effects by increasing the HSP levels.

Effects of zinc on epithelial barrier properties and viability in a human and a porcine intestinal cell culture model

Zinc is an essential trace element with a variety of physiological and biochemical functions. Piglets are commonly supplemented, during the weaning period, with doses of zinc above dietary requirements with positive effects on health and performance that might be attributed to anti-secretory and barrier-enhancing effects in the intestine. For a better understanding of these observations increasing zinc sulfate (ZnSO4; 0-200μM) concentrations were used in an in vitro culture model of porcine (IPEC-J2) and human (Caco-2) intestinal epithelial cells and effects on barrier function, viability, and the mRNA expression of one selected heat shock protein (Hsp) were assessed. When treated apically with zinc sulfate, the transepithelial electrical resistance (TEER) did not change significantly. In contrast, cell viability measured by lactate dehydrogenase (LDH) leakage, by ATP and by WST-1 conversion in postconfluent IPEC-J2 monolayers was affected after a 24-h treatment with 200μM ZnSO4. Caco-2 cells were more resistant to Zn. ZnSO4 did not induce any effect on viability, except when it was used at the highest concentration (200μM), and only in preconfluent cells. Furthermore, ZnSO4 induced Hsp70 mRNA expression at 200μM and was more pronounced in preconfluent cells. The observed dose-related effects of zinc are cell-line specific and depended on the differentiation status of the cells. The IPEC-J2 cell line appears to be a suitable in vitro model to characterize specific effects on porcine intestinal cells.

Dietary nitrate and reductive polyphenols may potentiate the vascular benefit and alleviate the ulcerative risk of low-dose aspirin

The recent revelation that daily low-dose aspirin not only lowers risk for vascular events, but also can notably decrease risk for a range of adenocarcinomas, decreasing total cancer mortality by about 20%, makes it highly desirable to implement this protective strategy on a population-wide basis. Nonetheless, the fact that low-dose aspirin approximately doubles risk for serious gastrointestinal bleeding may impede health authorities from recommending its use by people judged to be at low cardiovascular risk. Nitric oxide (NO) exerts gastroprotective effects by boosting blood flow and mucus production in the gastric mucosa - effects which demonstrably oppose the pro-ulcerative impact of aspirin and other NSAIDs. A nitrate-rich diet, as well as ingestion of reductive catechol-bearing polyphenols, can collaborate in promoting NO generation in gastric juice, and they are protective in rodent models of gastric ulceration. Moreover, a high-nitrate diet, as well as certain reductive polyphenols such as epicatechin and quercetin, can exert platelet-stabilizing effects complementary to those of aspirin, and act in other ways to preserve vascular health. Hence, diets rich in nitrate and reductive polyphenols have the potential to amplify the vascular-protective benefits of low-dose aspirin, while diminishing its pro-ulcerative risk. Low-dose aspirin may be more unequivocally recommendable within the context of such a dietary strategy.

Heme oxygenase-1 system and gastrointestinal inflammation: A short review

Heme oxygenase-1 (HO-1) system catalyzes heme to biologically active products: carbon monoxide, biliverdin/bilirubin and free iron. It is involved in maintaining cellular homeostasis and many physiological and pathophysiological processes. A growing body of evidence indicates that HO-1 activation may play an important protective role in acute and chronic inflammation of gastrointestinal tract. This review focuses on the current understanding of the physiological significance of HO-1 induction and its possible roles in the gastrointestinal inflammation studied to date. The ability to upregulate HO-1 by pharmacological means or using gene therapy may offer therapeutic strategies for gastrointestinal inflammation in the future.

Heat shock protein 70-dependent protective effect of polaprezinc on acetylsalicylic acid-induced apoptosis of rat intestinal epithelial cells

Protection of the small intestine from mucosal injury induced by nonsteroidal anti-inflammatory drugs including acetylsalicylic acid is a critical issue in the field of gastroenterology. Polaprezinc an anti-ulcer drug, consisting of zinc and L-carnosine, provides gastric mucosal protection against various irritants. In this study, we investigated the protective effect of polaprezinc on acetylsalicylic acid-induced apoptosis of the RIE1 rat intestinal epithelial cell line. Confluent rat intestinal epithelial cells were incubated with 70 µM polaprezinc for 24 h, and then stimulated with or without 15 mM acetylsalicylic acid for a further 15 h. Subsequent cellular viability was quantified by fluorometric assay based on cell lysis and staining. Acetylsalicylic acid-induced cell death was also qualified by fluorescent microscopy of Hoechst33342 and propidium iodide. Heat shock proteins 70 protein expression after adding polaprezinc or acetylsalicylic acid was assessed by western blotting. To investigate the role of Heat shock protein 70, Heat shock protein 70-specific small interfering RNA was applied. Cell viability was quantified by fluorometric assay based on cell lysis and staining and apoptosis was analyzed by fluorescence-activated cell sorting. We found that acetylsalicylic acid significantly induced apoptosis of rat intestinal epithelial cells in a dose- and time-dependent manner. Polaprezinc significantly suppressed acetylsalicylic acid-induced apoptosis of rat intestinal epithelial cells at its late phase. At the same time, polaprezinc increased Heat shock protein 70 expressions of rat intestinal epithelial cells in a time-dependent manner. However, in Heat shock protein 70-silenced rat intestinal epithelial cells, polaprezinc could not suppress acetylsalicylic acid -induced apoptosis at its late phase. We conclude that polaprezinc-increased Heat shock protein 70 expression might be an important mechanism by which polaprezinc suppresses acetylsalicylic acid-induced small intestinal apoptosis, a hallmark of acetylsalicylic acid-induced enteropathy.

Effects of dietary supplementation of carnosine on mitochondrial dysfunction, amyloid pathology, and cognitive deficits in 3xTg-AD mice

Background

The pathogenic road map leading to Alzheimer's disease (AD) is still not completely understood; however, a large body of studies in the last few years supports the idea that beside the classic hallmarks of the disease, namely the accumulation of amyloid-β (Aβ) and neurofibrillary tangles, other factors significantly contribute to the initiation and the progression of the disease. Among them, mitochondria failure, an unbalanced neuronal redox state, and the dyshomeostasis of endogenous metals like copper, iron, and zinc have all been reported to play an important role in exacerbating AD pathology. Given these factors, the endogenous peptide carnosine may be potentially beneficial in the treatment of AD because of its free-radical scavenger and metal chelating properties.

Methodology

In this study, we explored the effect of L-carnosine supplementation in the 3xTg-AD mouse, an animal model of AD that shows both Aβ- and tau-dependent pathology.

Principal Findings

We found that carnosine supplementation in 3xTg-AD mice promotes a strong reduction in the hippocampal intraneuronal accumulation of Aβ and completely rescues AD and aging-related mitochondrial dysfunctions. No effects were found on tau pathology and we only observed a trend toward the amelioration of cognitive deficits.

Conclusions and Significance

Our data indicate that carnosine can be part of a combined therapeutic approach for the treatment of AD.

The effect of zinc sulphate and zinc carnosine on genome stability and cytotoxicity in the WIL2-NS human lymphoblastoid cell line

Zinc (Zn) is an essential cofactor required by numerous enzymes that are essential for cell metabolism and the maintenance of DNA integrity. We investigated the effect of Zn deficiency or excess on genomic instability events and determined the optimal concentration of two Zn compounds that minimize DNA-damage events. The effects of Zn sulphate (ZnSO(4)) and Zn carnosine (ZnC) on cell proliferation were investigated in the WIL2-NS human lymphoblastoid cell line. DNA damage was determined by the use of both the comet assay and the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. Zn-deficient medium (0μM) was produced using Chelex treatment, and the two Zn compounds (i.e. ZnSO(4) and ZnC) were tested at concentrations of 0.0, 0.4, 4.0, 16.0, 32.0 and 100.0μM. Results from an MTT assay showed that cell growth and viability were decreased in Zn-depleted cells (0μM) as well as at 32μM and 100μM for both Zn compounds (P<0.0001). DNA strand-breaks, as measured by the comet assay, were found to be increased in Zn-depleted cells compared with the other treatment groups (P<0.05). The CBMN-Cyt assay showed a significant increase in the frequency of both apoptotic and necrotic cells under Zn-deficient conditions (P<0.0001). Elevated frequencies of micronuclei (MNi), nucleoplasmic bridges (NPBs) and nuclear buds (NBuds) were induced in Zn-depleted cells (P<0.0001), whereas genome damage was reduced in supplemented cultures for both Zn compounds at 4μM and 16μM, possibly suggesting that these concentrations may be optimal for genome stability. The potential protective effect of ZnSO(4) and ZnC was also investigated following exposure to 1.0Gy γ-radiation. Culture in medium containing these compounds at 4-32μM prior to irradiation displayed significantly reduced frequencies of MNi, NPBs and NBuds compared with cells maintained in 0μM medium (P<0.0001). Expression of γ-H2AX and 8-oxoguanine glycosylase measured by western blotting was increased in Zn-depleted cells. These results suggest that Zn plays important role in genomic stability and that the optimal Zn concentration-range for prevention of DNA damage and cytotoxicity in vitro lies between 4 and 16μM.

Heme oxygenase-1: a novel therapeutic target for gastrointestinal diseases

Heme oxygenase-1 (HO-1) is the rate-limiting enzyme in the catabolism of heme, followed by production of biliverdin, free iron and carbon monoxide (CO). HO-1 is a stress-responsive protein induced by various oxidative agents. Recent studies demonstrate that the expression of HO-1 in response to different inflammatory mediators may contribute to the resolution of inflammation and has protective effects in several organs against oxidative injury. Although the mechanism underlying the anti-inflammatory actions of HO-1 remains poorly defined, both CO and biliverdin/bilirubin have been implicated in this response. In the gastrointestinal tract, HO-1 is shown to be transcriptionally induced in response to oxidative stress, preconditioning and acute inflammation. Recent studies suggest that the induction of HO-1 expression plays a critical protective role in intestinal damage models induced by ischemia-reperfusion, indomethacin, lipopolysaccharide-associated sepsis, trinitrobenzene sulfonic acid, and dextran sulfate sodium, indicating that activation of HO-1 may act as an endogenous defensive mechanism to reduce inflammation and tissue injury in the gastrointestinal tract. In addition, CO derived from HO-1 is shown to be involved in the regulation in gastro-intestinal motility. These in vitro and in vivo data suggest that HO-1 may be a novel therapeutic target in patients with gastrointestinal diseases.

Polaprezinc prevents oral mucositis associated with radiochemotherapy in patients with head and neck cancer

Oral mucositis is frequent but serious adverse event associated with radiotherapy or radiochemotherapy in head and neck cancer severely impairs health-related quality of life, leading to poor prognosis due to discontinuation of the therapy. Although a number of compounds have been tested for prophylaxis of oral mucositis, few of them are satisfactory. We investigated the effect of polaprezinc (zinc L-carnosine), a gastric mucosal protective drug, on radiochemotherapy-induced oral mucositis, pain, xerostomia and taste disturbance in patients with head and neck cancer. Patients were randomly assigned to receive polaprezinc (n = 16) or azulene oral rinse as the control (n = 15). The incidence rates of mucositis, pain, xerostomia and taste disturbance were all markedly lower in polaprezinc group than in control. Moreover, the use of analgesics was significantly (p = 0.003) less frequent and the amount of food intake was significantly (p = 0.002) higher in polaprezinc group than in control. On the other hand, tumor response rate in patients with neoadjuvant radiochemotherapy was not significantly affected by polaprezinc, in which the response rate (complete plus partial response) was 88% for polaprezinc and 92% for control (p = 1.000). Therefore, it is highly assumable that polaprezinc is potentially useful for prevention of oral mucositis and improvement of quality of life without reducing the tumor response.

Sofalcone, a gastric mucosa protective agent, increases vascular endothelial growth factor via the Nrf2-heme-oxygenase-1 dependent pathway in gastric epithelial cells

Sofalcone, 2'-carboxymethoxy-4,4-bis(3-methyl-2-butenyloxy)chalcone, is an anti-ulcer agent that is classified as a gastric mucosa protective agent. Recent studies indicate heat shock proteins such as HSP32, also known as heme-oxygenase-1(HO-1), play important roles in protecting gastrointestinal tissues from several stresses. We have previously reported that sofalcone increases the expression of HO-1 in adipocytes and pre-adipocytes, although the effect of sofalcone on HO-1 induction in gastrointestinal tissues is not clear. In the current study, we investigated the effects of sofalcone on the expression of HO-1 and its functional role in rat gastric epithelial (RGM-1) cells. We found that sofalcone increased HO-1 expression in RGM-1 cells in both time- and concentration-dependent manners. The HO-1 induction was associated with the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in RGM-1 cells. We also observed that sofalcone increased vascular endothelial growth factor (VEGF) production in the culture medium. Treatment of RGM-1 cells with an HO-1 inhibitor (tin-protoporphyrin), or HO-1 siRNA inhibited sofalcone-induced VEGF production, suggesting that the effect of sofalcone on VEGF expression is mediated by the HO-1 pathway. These results suggest that the gastroprotective effects of sofalcone are partly exerted via Nrf2-HO-1 activation followed by VEGF production.

Reactive oxygen species-quenching and anti-apoptotic effect of polaprezinc on indomethacin-induced small intestinal epithelial cell injury

BACKGROUND

To protect the small intestine from mucosal injury induced by nonsteroidal anti-inflammatory drugs is one of the critical issues in the field of gastroenterology. Polaprezinc (PZ), a gastric muco-protecting agent, has been widely used for the treatment of gastric ulcer and gastritis for its unique effects, such as its strong reactive oxygen species (ROS)-quenching effect. The aim of this study was to clarify the mechanism by which indomethacin-induced small intestinal mucosal injury occurs, by using a rat intestinal epithelial cell line (RIE-1). In addition, the protective role of PZ and the possible mechanism of its effect on indomethacin-induced small intestinal injury were investigated.

METHODS

Cell death was evaluated by methyl thiazolyl tetrazolium (MTT) assay and a double-staining method with Hoechst33342 dye and propidium iodide. Indomethacin-induced ROS production was evaluated by detecting the oxidation of a redox-sensitive fluorogenic probe, RedoxSensor, and the oxidation of cysteine residues of proteins (protein S oxidation). The activation of cytochrome c, smac/DIABLO, and caspase-3 was assessed by western blotting. In some experiments, PZ or its components, L: -carnosine and zinc, were used.

RESULTS

We found that indomethacin caused apoptosis in RIE-1 cells in a dose- and time-dependent manner. Indomethacin also induced ROS production and an increase in the protein S oxidation of RIE-1. Pretreatment of RIE-1 with PZ or zinc sulfate, but not L: -carnosine, significantly reduced the indomethacin-induced apoptosis. PZ prevented ROS production and the increase in protein S-oxidation. PZ inhibited indomethacin-induced cytochrome c and smac/DIABLO release and subsequent caspase-3 activation.

CONCLUSIONS

The protective effect of PZ on indomethacin-induced small intestinal injury may be dependent on its ROS-quenching effect.