Polaprezinc protects gastric mucosal cells from noxious agents through antioxidant properties in vitro

The Effect of Quadruple Therapy with Polaprezinc or Bismuth on Gut Microbiota after Helicobacter pylori Eradication: A Randomized Controlled Trial

Background: Quadruple therapy with polaprezinc provided an alternative to Helicobacter pylori eradication; however, the effect on gut microbiota remains uncertain. This study aims to identify whether polaprezinc-containing quadruple therapy causes adverse microbiota effects among asymptomatic adults, compared with bismuth therapy. Methods: This was a randomized control trial. One hundred asymptomatic H. pylori-infected adults were randomly (1:1) assigned to two treatment groups (polaprezinc-containing therapy, PQT; or bismuth-containing therapy, BQT). Fecal samples were collected from subjects before and 4−8 weeks after therapy. Samples were sequenced for the V4 regions of the 16S rRNA gene. Results: The relative abundance of the three dominant bacterial phyla (Bacteroidota, Firmicutes, and Proteobacteria) accounted for more than 95% of each treatment group. The alpha diversity between eradications that succeeded and those that failed had no significant difference (p > 0.05). After successful eradication, the alpha diversity in the BQT group decreased in comparison with the baseline (p < 0.05). Subjects who were successfully eradicated by BQT showed considerably lower alpha diversity indices than those of the PQT at follow-up (p < 0.05). The abundance of Parasutterella in subjects who were successfully eradicated by PQT was four times greater than that of BQT (q < 0.05). Conclusion: A 14-day PQT may be superior to BQT in maintaining short-term gut microbiota homeostasis after H. pylori treatment. Our findings preliminarily provide evidence of the short-term impacts of the gut microbiota after PQT treatment of H. pylori infection.

Effectiveness of Nutritional Ingredients on Upper Gastrointestinal Conditions and Symptoms: A Narrative Review

Nutritional ingredients, including various fibers, herbs, and botanicals, have been historically used for various ailments. Their enduring appeal is predicated on the desire both for more natural approaches to health and to mitigate potential side effects of more mainstream treatments. Their use in individuals experiencing upper gastrointestinal (GI) complaints is of particular interest in the scientific space as well as the consumer market but requires review to better understand their potential effectiveness. The aim of this paper is to review the published scientific literature on nutritional ingredients for the management of upper GI complaints. We selected nutritional ingredients on the basis of mentions within the published literature and familiarity with recurrent components of consumer products currently marketed. A predefined literature search was conducted in Embase, Medline, Derwent drug file, ToXfile, and PubMed databases with specific nutritional ingredients and search terms related to upper GI health along with a manual search for each ingredient. Of our literature search, 16 human clinical studies including nine ingredients met our inclusion criteria and were assessed in this review. Products of interest within these studies subsumed the categories of botanicals, including fiber and combinations, and non-botanical extracts. Although there are a few ingredients with robust scientific evidence, such as ginger and a combination of peppermint and caraway oil, there are others, such as melatonin and marine alginate, with moderate evidence, and still others with limited scientific substantiation, such as galactomannan, fenugreek, and zinc-l-carnosine. Importantly, the paucity of high-quality data for the majority of the ingredients analyzed herein suggests ample opportunity for further study. In particular, trials with appropriate controls examining dose-response using standardized extracts and testing for specific benefits would yield precise and effective data to aid those with upper GI symptoms and conditions.

Study on the Local Anti-Osteoporosis Effect of Polaprezinc-Loaded Antioxidant Electrospun Membrane

Background

Compared with the healthy condition, osteoporotic bone defects are often accompanied by poor osteogenesis and excessive reactive oxygen species (ROS), which pose serious challenges to bone augmentation and repair by normal resorbable guided bone regeneration (GBR) membrane.

Purpose

Polaprezinc (PZ) was loaded into polycaprolactone/gelatin (PG) hybrid electrospun nanofibers to fabricate a GBR membrane with antioxidant and osteogenesis ability.

Methods

A series of physicochemical characterization were performed by scanning electron microscopy, Fourier-transform infrared spectroscopy, and water contact angle measurement. In addition to membrane degradation and PZ release detection, membranes were tested for cell viability, differentiation, and protein expression in MC3T3-E1 cells by CCK8, alkaline phosphatase activity, mineralization, and Western blotting assays. The membrane osteogenic capacity in cranial bone defects was studied by micro-CT in vivo.

Results

PZ was successfully doped into the PCL/GEL nanofibers to form a hydrophilic GBR membrane. The cumulative release of PZ was closely related to the membrane degradation behavior. PG/0.4%PZ membranes produced the best protective effect on cell proliferation/differentiation under oxidative stress microenvironment; however, the PG/0.8%PZ membrane was cytotoxic. Western blotting demonstrated that the PZ-loaded membrane upregulated the Nrf2/HO-1/SOD1 signaling molecules in a concentration-dependent manner. In addition, micro-CT results showed an abundant formation of new bones in the PG/0.4%PZ group compared to the PG group.

Conclusion

PZ-loaded degradable PG membranes (especially PG/0.4%PZ) have great potential to accelerate bone regeneration in oxidative stress-related diseases.

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.

Beneficial effect of polaprezinc on cardiac function post-myocardial infarction: A prospective and randomized clinical trial

BACKGROUND

Polaprezinc is clinically used for the treatment of gastric ulcers. It induces the mobilization of mesenchymal stem cells and the mRNA expression of insulin-like growth factor-1 in vascular endothelial cells in order to protect injured gastric tissue or skin.

METHODS

The current study population included 50 patients with primary acute myocardial infarction (AMI). After percutaneous coronary intervention, the subjects were randomly divided into 2 groups, namely, the nonpolaprezinc and polaprezinc groups. Peripheral blood and urinary samples were collected in a specific time to analyze zinc concentration, cardiac enzymes, and the levels of the inflammation marker interleukin-6. To evaluate the cardiac function, echocardiography was performed upon admission to the hospital and at 9 months post-AMI.

RESULTS

The urine and blood zinc levels of the polaprezinc group were higher compared with those of the non-polaprezinc group at 8 days after percutaneous coronary intervention. The mean interleukin-6/maximal creatine phosphokinase level was significantly reduced in the polaprezinc group (0.024 [0.003-0.066] vs. 0.076 [0.015-0.212], respectively; P = .045). In addition, echocardiography revealed that the ejection fraction of the nonpolaprezinc group was not significantly increased between day 3 and 9 months post-AMI (53 [49-60.8] vs. 59.5 [52-69.3], respectively; P = .015). However, a significant increase was detected in the ejection fraction of the polaprezinc group at the 2 time points (54 [51-57] vs. 62 [55-71], respectively; P < .01).

CONCLUSIONS

The results of the present study suggest that polaprezinc has an anti-inflammatory effect and improves cardiac function after AMI.

Effect of polaprezinc on experimental corrosive esophageal burns in rats

Unconsciously caustic ingestion is one of the most common causes of serious esophageal strictures in children. The aim of this study is to determine the efficiency of polaprezinc in preventing stricture formation after corrosive esophageal burns (CEB); this was the first time it has been used to treat experimental CEB in rats. Twenty-four rats were divided into four groups, three of which received CEB by the instillation of 1 mL of 10% NaOH solution into their isolated esophageal segments for three minutes. Group C (control) was uninjured and untreated. Group B (esophageal burn) received CEB but were left untreated. Groups PT1 and PT2 had CEB and received 100 mg/kg/day and 200 mg/kg/day, respectively, of intraperitoneal polaprezinc treatment (PT) for the first two weeks, then oral PT for another two weeks. We assessed the treatment's efficiency of the treatment after the fourth week by evaluating the stenosis index (SI) and the histopathological damage score, determining tissue hydroxyproline content (HP), and measuring the weight of the rats before and after the experiment. Mean SI was statistically lower in the groups PT1 and PT2 when compared with Group B (p = 0.006, 0.004, respectively). HP levels were highest in Group B, but it was insignificant (P> 0.05). In terms of histopathological damage score, treatment groups demonstrated less collagen deposition, mucosal, and submucosal damage than both Group B (p = 0.01) and Group C (p = 0.02). Group PT1 and Group PT2 (P> 0.05) showed similar results, indicating the treatment's effectiveness was independent of dosage. Outside of Group C, weight gain was detected only in Group PT2, though it was statistically insignificant. In Group PT1, weight loss was lower than in Group B. Polaprezinc, with its antifibrotic, antioxidant, anti-inflammatory, wound-healing and antiapoptotic effects, was efficient in reducing stricture formation by decreasing HP levels and histopathologic damage, preventing stenosis, and weight gain in higher dosages in the treatment group.

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.

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.

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.

Effect of a zinc L-carnosine compound on acid-induced injury in canine gastric mucosa ex vivo

OBJECTIVE

To examine whether a zinc L-carnosine compound used for treatment of suspected gastric ulcers in dogs ameliorates acid-induced injury in canine gastric mucosa.

SAMPLE

Gastric mucosa from 6 healthy dogs.

PROCEDURES

Mucosa from the gastric antrum was harvested from 6 unadoptable shelter dogs immediately after euthanasia and mounted on Ussing chambers. The tissues were equilibrated for 30 minutes in neutral Ringer's solution prior to incubation with acidic Ringer's solution (HCl plus Ringer's solution [final pH, 1.5 to 2.5]), acidic Ringer's solution plus zinc L-carnosine compound, or zinc L-carnosine compound alone. Tissues were maintained for 180 minutes in Ussing chambers, during which permeability was assessed by measurement of transepithelial electrical resistance. After the 180-minute treatment period, tissues were removed from Ussing chambers and labeled with immunofluorescent anti-active caspase-3 antibody as an indicator of apoptosis.

RESULTS

Permeability of the gastric mucosa was significantly increased in a time-dependent manner by addition of HCl, whereas control tissues maintained viability for the study period. Change in permeability was detected within the first 15 minutes after acid application and progressed over the subsequent 150 minutes. The zinc L-carnosine compound had no significant effect on this increase in permeability. Apoptosis was evident in acid-treated tissues but not in control tissues. The zinc L-carnosine compound did not protect against development of apoptosis.

CONCLUSIONS AND CLINICAL RELEVANCE

Addition of HCl caused a dose-dependent increase in gastric permeability over time and apparent induction of apoptosis as determined on the basis of immunofluorescence. However, there was no significant protective effect of a zinc L-carnosine compound. Nonetheless, results suggested the utility of this method for further studies of canine gastric injury.

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.

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.

Early and presymptomatic detection of Wilson's disease at the mandatory 3-year-old medical health care examination in Hokkaido Prefecture with the use of a novel automated urinary ceruloplasmin assay

Wilson's disease (WND) is an autosomal recessive disorder of copper (Cu) accumulation leading to liver and/or brain damage. Oral chelating agents and diet are effective in treating WND. However, once irreversible damage has occurred, the effect of treatment is diminished and the patient's quality of life is compromised. For these reasons an effective method for screening has been needed for early detection of presymptomatic patients. We conducted an early and presymptomatic detection of WND using a novel automated assay of ceruloplasmin (Cp) concentration in urine and selected the mandatory medical health care examination for 3-year-old children in Hokkaido Prefecture (the largest administrative division in Japan) as a sampling point. We measured urinary Cp concentrations in 11,362 children using an immunological latex agglutination assay kit developed by us. Among these children we identified a positive case with markedly reduced urinary Cp concentration. Detailed medical examination provided no clinical manifestations to support the diagnosis of WND, although serum Cp and Cu levels were remarkably low in this case. Therefore, we analyzed the WND gene in order to confirm the diagnosis. Sequence analysis revealed that the case was compound heterozygous for the WND gene mutations 2871del.C and D1296N. According to the Ferenci scoring system for WND diagnosis, the case was established as a WND patient at the presymptomatic stage. Consequently, the patient has maintained a good quality of life under medical treatment with polaprezinc administration to date. Our investigation suggests that the screening system for WND using the automated urinary assay at the mandatory medical health care examination for 3-year-old children is a noninvasive and efficient method for the early and presymptomatic diagnosis of WND.

Carnosine promotes the heat denaturation of glycated protein

Glycation alters protein structure and decreases biological activity. Glycated proteins, which accumulate in affected tissue, are reliable markers of disease. Carnosine, which prevents glycation, may also play a role in the disposal of glycated protein. Carnosinylation tags glycated proteins for cell removal. Since thermostability determines cell turnover of proteins, the present study examined carnosine's effect on thermal denaturation of glycated protein using cytosolic aspartate aminotransferase (cAAT). Glycated cAAT (500 microM glyceraldehyde for 72h at 37 degrees C) increased the T(0.5) (temperature at which 50% denaturation occurs) and the Gibbs free energy barrier (DeltaG) for denaturation. The enthalpy of denaturation (DeltaH) for glycated cAAT was also higher than that for unmodified cAAT, suggesting that glycation changes the water accessible surface. Carnosine enhanced the thermal unfolding of glycated cAAT as evidenced by a decreased T(0.5) and a lowered Gibbs free energy barrier. Additionally, carnosine decreased the enthalpy of denaturation, suggesting that carnosine may promote hydration during heat denaturation of glycated protein.

Polaprezinc attenuates Helicobacter pylori-associated gastritis in Mongolian gerbils

BACKGROUND

The ammonia-monochloramine system plays an important role in Helicobacter pylori-associated gastric mucosal injury. Polaprezinc, a new antiulcer agent, has a scavenging action against monochloramine. The aim of the experiment was to investigate the inhibitory effects of polaprezinc on the H. pylori-induced gastritis in Mongolian gerbils.

MATERIALS AND METHODS

Mongolian gerbils fasting for 24 hours were orally given culture broth containing 2-4 x 10(8) colony-forming units of H. pylori ATCC 43054 per milliliter. From 4 hours after inoculation until the end of the experiment, gerbils were given chow pellets with or without 0.02% polaprezinc. All gerbils were killed 12 weeks later. The grades of H. pylori density and histologic features of gastritis were evaluated in accordance with the Updated Sydney System. The scavenging effect of polaprezinc on monochloramine was investigated spectrophotometrically.

RESULTS

Polaprezinc had little or no influence on the H. pylori density in both pyloric and fundic mucosae. However, it significantly attenuated the development of polymorphonuclear neutrophil activity, mononuclear infiltration, and surface epithelial erosion in both pyloric and fundic mucosae compared with those of the control group. H. pylori inoculation significantly increased the heights of both pyloric and fundic mucosae (mainly due to the increased height of foveolar hyperplasia), but polaprezinc inhibited the increase of mucosal thickness in both pyloric and fundic mucasae. No intestinal metaplasia was detected in this study. Spectrophotometric examination revealed that polaprezinc scavenged monochloramine.

CONCLUSIONS

Polaprezinc inhibited the development of H. pylori-induced gastritis through its scavenging action against monochloramine.

Effects of thermal denaturation on protein glycation

Protein denaturation occurs at sites of inflammation. We hypothesized that denatured protein may provide a more susceptible target for glycation, which is a known mediator of inflammation. We examined the effects of thermal denaturation on the susceptibility of protein glycation using glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and aspartate aminotransferase (AAT) as our target proteins. GAPDH and AAT are ubiquitous proteins that exhibited very different thermal stabilities. Glycating agents, methylglyoxal (MG) and glyceraldehyde (Glyc), caused an increase in the formation of advanced glycation endproducts (AGEs) in native and denatured GAPDH and AAT. The effects of the glycating agents were more pronounced with the denatured proteins. In addition to nitroblue tetrazolium (NBT)- reactivity, our measured endpoints were absorbance (lambda = 365 nm) and fluorescence (lambda(ex) = 370 nm; lambda(em) = 470 nm) properties that are typically associated with protein glycation. We also looked at carnosine's ability to prevent glycation of native and denatured protein. Carnosine, an endogenous histidine dipeptide, exhibits anti-inflammatory activity presumably due to its anti-oxidant and anti-glycation properties. Carnosine prevented Glyc-induced AGE formation in both native and denatured AAT suggesting that carnosine's anti-inflammatory activity may be due in part to carnosine's ability to prevent glycation of denatured protein.

Cell culture model for antiulcerogenic agents

To elucidate the mechanisms of antiulcerogenic agents, we established the cell culture model derived from rat gastric epithelium. The cultured cells were identified as mucus-producing cells by using histological analysis. This culture model is useful for investigating the untiulcer effect of various agents and to reveal the mechanisms of the drug action. In particular, the ulcer-healing model using the cultured monolayer is promising and convenient for the study of several growth factors such as HGF as well as antiulcerogenic agents. The effect of polaporezinc in the cultured model is introduced.

Raman and IR spectroscopic investigation of zinc(II)-carnosine complexes

The zinc(II)-L-carnosine system was investigated at different pH and metal/ligand ratios by Raman and IR spectroscopy. The Raman and IR spectra present some marker bands useful to identify the sites involved in metal chelation at a specific pH value. In particular, the neutral imidazole group gives rise to some Raman bands, such as the nu C(4)===C(5) band, that change in wave number, depending on whether the imidazole ring takes the tautomeric form I or II. Even if tautomer I is predominant in the free ligand, metal coordination can upset tautomeric preference and N(tau)- and N(pi)-ligated complexes can be identified. Although weak compared to those of aromatic residues, these Raman marker bands may be useful in analyzing metal-histidine interaction in peptides and proteins. On the basis of the vibrational results, conclusions can be drawn on the species existing in the system. Depending on the available nitrogen atoms, various complexes can be formed and the prevalent form of the species depends mainly on the pH. At basic pH carnosine gives rise to two different neutral complexes: a water-insoluble polymeric species, [ZnH(-1)L](0)(n), and a dimer, [Zn(2)H(-2)L(2)](0). The first is predominant and involves the tautomeric I form of the imidazole ring in metal chelation; the second contains tautomer II and increases its percentage by going from a 2 to 0.25 metal/ligand ratio. Conversely, the dimeric species dominates at pH 7, whereas two charged species, [ZnHL](2+) and [ZnL](+), are formed under slightly acidic conditions. In the [ZnHL](2+) complex the imidazole ring takes part in the Zn(II) coordination in the tautomeric I form, whereas in [ZnL](+) the ring is protonated and not bound to the Zn(II) ion. In addition, the curve fitting analysis of the 1700-1530 cm(-1) Raman region was helpful in indicating the predominant species at each pH.