Fresh Gastric Tissues Research Articles

Comparable Results of Helicobacter pylori Antibiotic Resistance Testing of Stools vs Gastric Biopsies Using Next-Generation Sequencing

Comparable Results of Helicobacter pylori Antibiotic Resistance Testing of Stools vs Gastric Biopsies Using Next-Generation Sequencing

Abstract 2523: Loss of expression of wild-type transcript of CDH1 gene is associated with overexpression of microRNA-20 in diffuse-type of gastric cancer

Abstract Background: Gastric cancer (GC) is the third cause of cancer death in the world. In Latin America, GC is one of the leading causes of death, particularly in Chile. E-cadherin has been classified as a tumor suppressor gene that participates in cell adhesion. Reduction or loss of E-cadherin expression could promote tumor progression particularly in the sporadic diffuse subtype of GC (SDGC). In addition, inactivation germline mutations of CDH1 (E-cadherin gene) have been linked to the hereditary diffuse gastric cancer (HDGC) syndrome. Methods: We evaluated the expression of E-cadherin by Immunohistochemistry (IHC) in SDGC (n=27) and HDGC (n=22) cohorts. We also analyzed, by Sanger sequencing the full coding region of CDH1 in both cohorts. To identified miRNA-CDH1 interactions, an in silico analysis by mirWalk 2.0 software (5 or more algorithms) was performed. To validated in silico findings, 10 paired tumor and normal matched fresh gastric tissues were analyzed by miQ-PCR (miRNA) and qRT-PCR assay (CDH1 transcript) were performed. Results: The expression analysis of E-cadherin showed loss of expression in 13/27 (48%) SDGC and in 19/22 (90%) HDGC cases, respectively. The decrease of E-cadherin expression was significantly higher in the hereditary cohort (p=0.002, χ2: 9.12, 95%CI:13.0-63.3). Exome sequence analysis of the full coding region of CDH1 identified 3 and 9 mutations in SDGC and HDGC, respectively. Correlation between loss of protein expression by IHC and mutations was not found. Next, we explore the role of miRNA, as an alternative mechanism of the loss of E-cadherin protein expression. In silico analysis identified 417 miRNAs candidates with predicted binding sites. Among these candidates, all members of the polycistronic cluster miR-17/92 have seed regions against the 3'-UTR of the CDH1 transcript. Levels of expression of all 6 members of the polycistronic cluster were validated against CDH1 expression in paired normal and tumor fresh tissues of SDGC. A strong inverse correlation between the overexpression of miR-20a and downregulation of CDH1 transcript was found exclusively in tumor tissue (p= 0.0267) but not in normal counterparts. These results were validated in the STAD-TCGA cohort. Conclusions: Our results might explain the loss of expression of CDH1 in GC due to overexpression miR-20, a member of the polycistronic cluster miR-17/92. Future experimental validation of the predicted seed region will be necessary to confirm these findings. Grant support: CONICYT-FONDAP-15130011, Fondecyt-1191928 Citation Format: Natalia Landeros, Maria A. Alarcon, Graciela Molina, Pablo Santoro, Keila Torres, Wilda Olivares, Ignacio Wichmann, Franz Villarroel-Espindola, Iva Polakovicova, Enrique Norero, Alejandro H. Corvalan. Loss of expression of wild-type transcript of CDH1 gene is associated with overexpression of microRNA-20 in diffuse-type of gastric cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2523.

Characterization and strong risk association of TLR2 del -196 to -174 polymorphism and Helicobacter pylori and their influence on mRNA expression in gastric cancer.

BACKGROUNDToll-like receptor-2 (TLR2) is responsible for recognizing Helicobacter pylori (H. pylori) and activating the immune response. Polymorphisms in TLR2 may modulate gastric carcinogenesis.AIMTo evaluate whether the TLR2 19216T/C (rs3804099) and TLR2 -196 to -174 ins/del (rs111200466) polymorphisms contribute to gastric carcinogenesis in the Brazilian population, and to determine the influence of both polymorphisms and H. pylori infection on TLR2 mRNA expression.METHODSDNA was extracted from 854 peripheral blood leukocyte or gastric tissue samples [202 gastric cancer (GC), 269 chronic gastritis (CG), and 383 control/healthy (C)] and genotyped by allele-specific PCR or restriction fragment length polymorphism (RFLP)-PCR. Quantitative polymerase chain reaction by TaqMan® assay was used to quantify TLR2 mRNA levels in fresh gastric tissues (48 GC, 36 CG, and 14 C).RESULTSRegarding the TLR2 -196 to -174 polymorphism, the ins/del and del/del genotypes were associated with a higher risk of GC by comparison with the C in all of the analyzed inheritance models (codominant, dominant, recessive, overdominant and log-additive; P < 0.0001). Similarly, an increased risk was observed when comparing the GC and CG groups [codominant (P < 0.0001), dominant (P < 0.0001), recessive (P = 0.0260), overdominant (P < 0.0001) and log-additive (P < 0.0001)]. In contrast, TLR2 19216T/C was associated with a protective effect in the GC group compared to the C group [dominant (P = 0.0420) and log-additive (P = 0.0300)]. Regarding the association of polymorphisms with H. pylori infection, individuals infected with H. pylori and harboring the TLR2 -196 to -174 ins/del polymorphism had an increased risk of gastric carcinogenesis [codominant (P = 0.0120), dominant (P = 0.0051), overdominant (P = 0.0240) and log-additive (P = 0.0030)], while TLR2 19216T/C was associated with a protective effect [codominant (P = 0.0039), dominant (P < 0.0001), overdominant (P = 0.0097) and log-additive (P = 0.0021)]. TLR2 mRNA levels were significantly increased in the GC group (median RQ = 6.95) compared to the CG group (RQ = 0.84, P < 0.0001) and to the normal mucosa group (RQ = 1.0). In addition, both H. pylori infection (P < 0.0001) and the presence of the polymorphic TLR2 -196 to -174del (P = 0.0010) and TLR2 19216 C (P = 0.0004) alleles influenced TLR2 mRNA expression.CONCLUSIONThe TLR2 -196 to -174 ins/del and TLR2 19216 T/C polymorphisms are strongly associated with GC. TLR2 mRNA expression levels are upregulated in neoplastic tissues and influenced by both the presence of H. pylori and variant genotypes.

Investigation of Fresh Gastric Normal and Cancer Tissues Using Terahertz Time-Domain Spectroscopy.

In recent times, terahertz (THz) technologies have been actively applied in many biomedical research work, including gastric cancer diagnosis. In order to provide an effective removal of tumor during surgery, it is necessary to clearly distinguish it from different membranes of the stomach. In this work, we reported an investigation of various normal and cancer fresh gastric tissues using terahertz time-domain spectroscopy in the reflection mode. Refractive index and absorption coefficient of moderately differentiated and poorly differentiated gastric adenocarcinomas, as well as both serosa and mucosa were obtained in the frequency range from 0.2 to 1 THz. All cancer tissues were distinguishable from normal ones. The influence of the morphology of the investigated tissues on the obtained optical properties is discussed. The obtained results demonstrated a potential of THz time-domain spectroscopy to discriminate a tumor from normal serous and mucous gastric membranes. Thus, this method might be applied to gastric cancer diagnosis.

Toll-like receptor 9 polymorphisms and Helicobacter pylori influence gene expression and risk of gastric carcinogenesis in the Brazilian population.

BACKGROUNDToll-like receptors (TLRs) are the first line of host defense, and are involved in Helicobacter pylori (H. pylori) recognition and activation of both inflammatory and carcinogenic processes. The presence of single nucleotide polymorphisms (SNPs) in genes that activate the immune response may modulate the risk of precancerous lesions and gastric cancer (GC). Among them, Toll-like receptor 9 (TLR9) polymorphisms have emerged with a risk factor of infectious diseases and cancer, however the studies are still inconclusive.AIMTo evaluate whether TLR9 rs5743836 and rs187084 SNPs contribute to the risk of gastric carcinogenesis, and its influence on mRNA expression.METHODSA case-control study was conducted to evaluate two TLR9 SNPs (TLR9-1237 TC-rs5743836 and TLR9-1486 CT-rs187084) in chronic gastritis (CG) and GC patients. A total of 609 DNA samples of peripheral blood [248 CG, 161 GC, and 200 samples from healthy individuals (C)] were genotyped by polymerase chain reaction-restriction fragment length polymorphism. All samples were tested for the H. pylori infection using Hpx1 and Hpx2 primers. Quantitative polymerase chain reaction by TaqMan® assay was used to quantify TLR9 mRNA from fresh gastric tissues (48 GC, 26 CG, and 14 C).RESULTSFor TLR9-1237, the TC + CC or CC genotypes were associated with a higher risk of GC than C [recessive model odds ratio (OR) = 5.01, 95% confidence interval (CI): 2.52-9.94, P < 0.0001], and the CG (recessive model OR =4.63; 95%CI: 2.44-8.79, P < 0.0001) groups. For TLR9-1486, an association between the CT + TT genotypes and increased risk of both GC (dominant model OR = 2.72, 95%CI: 1.57-4.72, P < 0.0001) and CG (dominant model OR = 1.79, 95%CI: 1.15-2.79, P = 0.0094) was observed when compared to the C group. Moreover, the presence of TLR9-1237 TC/CC + TLR9-1486 CC genotypes potentiate the risk for this neoplasm (OR = 18.57; 95%CI: 5.06-68.15, P < 0.0001). The TLR9 mRNA level was significantly higher in the GC group (RQ = 9.24, P < 0.0001) in relation to the CG group (RQ = 1.55, P = 0.0010) and normal mucosa (RQ = 1.0). When the samples were grouped according to the polymorphic genotypes and the presence of H. pylori infection, an influence of TLR9-1237 TC + CC polymorphic genotypes (P = 0.0083) and H. pylori infection (P < 0.0001) was observed on the upregulation of mRNA expression.CONCLUSIONOur findings show that TLR9 rs5743836 and rs187084 polymorphisms are associated with a higher risk of carcinogenesis gastric, and that TLR9 mRNA levels can be modulated by TLR9-1237 TC + CC variant genotypes and H. pylori infection.

Abstract 3794: Understanding H. pylori-related gastric MALToma using multi-omics data

Abstract Mucosa-associated lymphoid tissue lymphoma (MALToma) is an extranodal B cell lymphoma, predominantly associated with bacterial infection of the stomach by Helicobacter pylori (H. pylori). Infection of H. pylori can be divided into four steps: 1) entrance into host and survival; 2) motility and chemotaxis; 3) Interaction between adhesion-receptors and colonization, and 4) release of toxins and damage to host. To date, pathogenesis of bacteria related lymphoma and individual functions of H. pylori genes are not yet unearthed. Hence, we aim to characterize the carcinogenic mechanism of H. pylori-related MALToma throughout this study.We obtained fresh gastric tissues of both tumor and adjacent normal region from MALToma patients. Using the tissue and saliva samples, we generated 12 sets of whole exome and transcriptome sequencing data. To identify the gene expression pattern, we aligned the raw data using STAR algorithm and quantified expression of genes in both H. pylori and human genome. Next, we estimated the relative abundance of immune cells in each tissue, employing a linear support vector regression (SVR) based analytical algorithm, CIBERSORT. Besides, we investigated somatic mutations in the patients using our internal pipeline.Gene expression profiling of H. pylori enabled us to identify frequently expressed genes in MALToma, and among them, aliphatic amidase (aimE) was expressed in 9 of 21 lesion tissues. The role of aimE is to contribute to ammonia production, which is analogous to that urease. Then, we explored gene expression pattern of immune checkpoint modulators. We determined that major groups of high CD112, CD155, and VISTA expression, and minor groups of high CD86 and PD-L1 expression, signifying cell adhesion and regulation of T cell activation.From CIBERSORT data, we found that increment of resting CD4 memory T cells and decrease of plasma cells in pair-wise MALToma donors. Since CD4+ T cells are abundantly distributed in the gastric cellular infiltrates, this immune cell composition implies that CD4 memory T cells might have been re-activated by exposure to bacterial antigens. In addition, majority of B cells including plasma cells die after they fight against infected cells, and this supports the decreased plasma cells in the tumor tissues.Using exome sequencing data, we identified two recurrent missense mutations (K169R and N175S) of a cell cycle gene, CDC27, in ~20% of MALToma patients. across the donors. Previous studies mentioned that impaired functions of CDC27 facilitate cell growth as it fails to regulate the cell growth inhibition.To understand carcinogenesis of H. pylori-related MALToma, we focused on determining gene expression patterns, immune cell composition, and recurrent somatic mutations. In conclusion, we demonstrated expression profiling of both H. pylori genes and human checkpoint modulators, estimation of immune cell abundance, and verification of recurrent DNA mutations, in MALToma. Citation Format: Hyojin Song, Eun Ae Kang, Hosim Soh, Sungyoung Lee, Hongseok Yun, Hyunsoo Chung, Jaeyoung Chun, Sung-Soo Yoon, Youngil Koh. Understanding H. pylori-related gastric MALToma using multi-omics data [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3794.

Long Noncoding RNA N-BLR Upregulates the Migration and Invasion of Gastric Adenocarcinoma.

Background/AimsGastric cancer is one of the most common malignant tumors worldwide with poor prognosis due to a lack of effective treatment modalities. Recent research showed that a long noncoding RNA named N-BLR modulates the epithelial-to-mesenchymal transition (EMT) process in colorectal cancer. However, the biological role of N-BLR in gastric cancer still remains to be explored. The aim of this study was to investigate the possibility of N-BLR as an EMT modulator in gastric cancer.MethodsThe expression of N-BLR was measured by quantitative polymerase chain reaction in fresh gastric cancer tissue, paired adjacent normal tissues and cell lines. Fresh gastric tissues, paired samples obtained by surgery and clinical data were collected prospectively. Knockdown of N-BLR was induced by small interfering RNA (siRNAs). Cell number and viability were assessed after treatment with siRNAs. The ability of N-BLR to promote metastasis was measured using migration and invasion assays. Additionally, an inverse correlation between N-BLR and miR-200c was measured by TaqMan microRNA assays. Western blotting was performed to detect EMT and apoptosis markers upon knockdown of N-BLR.ResultsN-BLR expression was significantly elevated in gastric cancer cell lines and tissues compared to that in a normal gastric cell line and adjacent normal tissues (p<0.01). Two different siRNAs significantly reduced cell proliferation of gastric cancer cells compared to the siCT. siRNAs for N-BLR significantly suppressed migration and invasion in AGS and MKN28 cells. N-BLR expression was inversely correlated with miR-200c, which is known to regulate EMT.ConclusionsIn this study, we confirmed N-BLR as a regulator of the EMT process in gastric cance

Corrigendum] Inhibition of sphingosine-1-phosphate phosphatase1 promotes cancer cells migration in gastric cancer: Clinical implications.

We have recently noticed an accidental error in part of a figure which appeared in the above‑mentioned article. In Fig.3A, the image for the HGC27‑pEF, 15h panel was mistakenly replicated as the HGC27‑KD, 0h panel in the same figure, and the AGS‑pEF, 15h and AGS KD, 0h panels were mistakenly switched with each other. We have reviewed the original files and the individual figures for the submitted composite figure, and realized that the error occurred when we produced the composite figure by marrying the individual images to the final figure. The same image was accidentally pasted twice without us being fully aware of the error. We have identified all the original images, and the corrected version of Fig. 3 is shown below. We regret that this error occurred, and thank the Editor for affording us the opportunity to publish this Corrigendum. [the original article was published in the Oncology Reports 34: 1977-1987, 2015; DOI: 10.3892/or.2015.4162].

Label-free imaging for T staging of gastric carcinoma by multiphoton microscopy.

Gastric cancer is one of the most common malignancies worldwide. The accurate diagnosis of tumor invasion depth is critical for therapeutic strategy and prognosis. Without fluorescent labelling, multiphoton microscopy (MPM) imaging could directly reveal tissue architecture based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). In this study, we aimed to explore the feasibility of MPM imaging to assess the gastric tumor morphology and infiltration. Unstained slides of 18 fresh gastric tissues with different T staging were examined by multiphoton microscopy. Morphological and quantitative analyses were both conducted. The nuclear area was defined as the area of nuclear boundary. Collagen content was defined as the ratio of SHG pixels to all pixels. Gastric normal and tumor tissues under different T stages visually presented with cellular and subcellular features on fluorescent imaging. The nuclear areas of normal and cancerous cells were 32.01 ± 2.89 and 58.41 ± 6.06μm2 (P < 0.001), respectively. Collagen content was quantified as 0.087 ± 0.012 in normal mucosa but 0.020 ± 0.007 in cancerous mucosa (P < 0.001). All results were in accord with the paired H&E-stained slides. Our findings suggested the convincing potential of MPM for judging T staging of gastric cancer. Without staining intervention, TPEF and SHG of MPM imaging could objectively and quantitatively indicate the subcellular and molecular changes during carcinogenesis. With the advancement of deep penetration, self-focus imaging and three-dimensional (3D) visualization, label-free MPM imaging compacted with endoscopy could be further introduced to realize the real-time in vivo assessment of tumor invasion clinically.

Differential expression of aristaless-like homeobox 4: a potential marker for gastric adenocarcinoma.

The objective of this experiment was to evaluate the ALX-4 mRNA expression level in different stages of human gastric adenocarcinoma compared to the gastric cancer stem cells (GCSC) and gastric cancer cell line, MKN-45. Gastric cancer is the second most common cancer in the world today, leading approximately to 3-10% of all cancer-related deaths. Identification of specific biomarkers could be a crucial approach to improve diagnosis and treatment of this cancer type. Recent findings emphasized on the up-regulation of Aristaless-Like Homeobox 4 (ALX-4) gene expression in several tumors. MKN-45 cell culture was prepared, and gastric cancer stem cell (GCSC) isolation was performed by flowcytometry. Then, 37 fresh gastric tissue samples from cancer patient were subjected for expression analysis by quantitative RT-PCR, prior to any therapeutic intervention in the comparative study for evaluation of ALX-4 gene expression. GCSCs with cuboidal shape as well as a positive expression of CD105, CD44, CD90 and negative for CD45, CD34 markers were identified. Overexpression of ALX-4 was detected in 46% (3.351±2.94, P<0.05) of gastric cancer tissue specimens and GCSCs (4.31±0.04, P<0.005). The mRNA expression level of ALX-4 in MKN-45 gastric cancer cell line was 2.81±0.07 (P<0.005). We determined that ALX-4 mRNA level significantly correlated with the tumor grade (P=0.004), stage (p=0.000153), but not gender (P= 0.06). These results documented the important role of ALX-4 in GCSCs, as an oncogene in progressive cancer, and valuable target in the treatment of drug resistant tumors.

Inhibition of sphingosine-1-phosphate phosphatase 1 promotes cancer cells migration in gastric cancer: Clinical implications.

Sphingosine-1-phosphate (S1P) plays an important role in regulating many biological processes. Sphingosine-1-phosphate phosphatase 1 (SGPP1) can dephosphorylate S1P into sphingosine and tip the balance of sphingosine-S1P. Increased levels of sphingosine leads to a decrease in the ability of cell invasion as well as an increase in the ability of cell apoptosis. However, little is known regarding the effects of SGPP1 in gastric cancer. The present study examined the function of SGPP1 on gastric cancer cell lines as well as its clinical relevance in gastric cancer progression. Using immunohistochemistry and RT-qPCR techniques, the clinical significance of SGPP1 expression was analyzed in 288 paraffin-embedded gastric tissue specimens and 219 fresh gastric tissues, respectively. Transgenes encoding ribozymes to specifically target human SGPP1 (pEF-SGPP1) was constructed. Human gastric cancer cell lines (AGS and HGC27) were transfected with pEF-SGPP1 transgene and examined by functional analysis. SGPP1 was downregulated in gastric cancer tissues, compared with adjacent normal gastric tissues (p=0.034). SGPP1 mRNA levels in gastric cancer tissues were significantly decreased when compared with their adjacent non-cancerous tissues (p<0.001). Weakly expressed SGPP1 was positively correlated with the lymph node metastasis (p=0.005) and distant metastasis (p=0.031). Kaplan-Meier survival curves revealed that patients with SGPP1 positive expression had a significant increase in overall survival (OS) (p=0.034) and progression-free survival (PFS) (p=0.041). Multivariate analysis indicated the expression of SGPP1 was an independent prognostic factor in gastric cancer patients (p=0.041). In vitro experiments showed that knockdown of SGPP1 resulted in an increase in the invasion (2-fold) and migration (5-fold) of AGS and HGC27. The two gastric cancer cells transfected with pEF-SGPP1 exhibited a slower rate of growth with less adhesion. Thus, our findings provided evidence that SGPP1 may serve as a prognostic biomarker for patients with advanced gastric cancers.

Establishment of Mongolian gerbil model of gastric cancer induced by Helicobacter pylori infection and its proteomics analysis

To establish an animal model of gastric cancer by long-term infection of Helicobacter pylori (H.pylori) and to elucidate the pathogenesis by proteomics analysis. Fifty male Mongolian gerbils (4-5 week-old and weighted 60-100 g) were infected with H.pylori and the gastric tissues were obtained after the infection at 3, 6, 12 and 24 months. Histological changes were evaluated by H-E staining of the gastric tissue sections. Detection of H.pylori was performed by in-vitro culture of fresh gastric tissue samples, PCR amplification of H.pylori 16s rRNA and localization by silver staining. In addition, proteins extracted from gastric tissue samples were subjected to two-dimensional electrophoresis (2-DE) at various infection time points. Protein spots with increased quantity over the course of H.pylori infection were selected and analyzed by LC-MS/MS. Finally, differentially expressed proteins between human gastric cancer tissue samples and lymph nodes were analyzed by real-time RT-PCR. Colonization of H.pylori was observed in gastric tissue of gerbils as early as 3 months after H.pylori infection, and persisted till 24 months. Pathological examination of infected animals showed various histological changes including acute gastritis, atrophic gastritis, intestinal metaplasia and gastric carcinoma. Seventy-eight differentially expressed proteins were identified by proteomics analysis, among which 36 proteins were up-regulated and 42 were down-regulated. Analyzed by LC-MS/MS, ten proteins were identified, including lactate dehydrogenase, ATP synthase, fatty acid-binding protein, COX5B, peroxiredoxin-4, peroxide reductase, transgelin, succinyl-CoA ligase, keratin and protein disulfide-isomerase A2, among which transgelin, ATP synthase and lactate dehydrogenase were highly expressed in human gastric carcinoma and lymph nodes. H.pylori infection induces the expression of transgelin, ATP synthase and lactate dehydrogenase, implying possible roles in the pathogenesis of gastric diseases including cancer.

Correlation between expressions of ERCC1/TS mRNA and effects of gastric cancer to chemotherapy in the short term

To study the correlation between expression levels of ERCC1/TS mRNA and the susceptibility of preoperative chemotherapy for patients with gastric cancer. A total of forty cases with advanced gastric cancer of T3-4N1-2M0 were treated with preoperative chemotherapy according to FLEEOX regimen based on endarterial-intravenous coadministration. Sufficient, fresh gastric tissue specimens were obtained with the help of gastroscope, and the expression levels of ERCC1/TS mRNA were detected by qRT-PCR before chemotherapy. The chemotherapeutic response was evaluated with Choi Criteria after chemotherapy, and pathologic remission extent was observed after surgery. The correlation between the expression levels of ERCC1/TS mRNA before chemotherapy and the chemotherapeutic effect based on imageology and pathology was analyzed. The response rate of Chemotherapy in this cohort was 80.0 % based on imageology and 51.43 % based on pathology. The expression levels of ERCC1/TS mRNA were significantly associated with imageology remission extent (P = 0.033, P = 0.025) and pathologic remission extent (P = 0.044, P = 0.016), respectively. The chemotherapeutic effect on patients with low-expression levels of ERCC1/TS mRNA was better. From the perspective of pathology and imageology evaluating the preoperative chemotherapeutic response for patients with gastric cancer, ERCC1 and TS were used as the molecular predictors and provided prognostic information in this study.

Ghrelin against alendronate-induced gastric damage in rats

Alendronate sodium, a primary amino bisphosphonate, is widely used in the treatment of various diseases that are associated with bone resorption, such as postmenopausal osteoporosis and Paget's disease of bone. Although the adverse effects of biphosphonates on the gastrointestinal system have been demonstrated in experimental and clinical studies, the exact mechanisms underlying this damage are not clear yet. Ghrelin, a 28 amino acid peptide produced predominantly by the stomach, was shown to exert a potent protective action on the stomach of rats exposed to ethanol or stress. Our objective was to evaluate the possible anti-oxidant and anti-inflammatory effects of ghrelin against alendronate-induced gastric damage. Wistar albino rats were administered alendronate (20 mg/kg) by gavage for 4 days, along with either ghrelin (10 ng/kg per day) or saline given i.p. After decapitation, stomach tissues were removed for the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and tissue collagen content, while the extent of tissue damage was analyzed microscopically. Formation of reactive oxygen species was determined by chemiluminesence using a luminol probe in fresh gastric tissues. Serum tumor necrosis factor (TNF-alpha) and lactate dehydrogenase levels were assessed in trunk blood. Oral administration of alendronate-induced significant gastric damage, accompanied by increased MPO activity, collagen content, MDA and luminol levels (P < 0.01-P < 0.001), while tissue GSH was decreased (P < 0.01). On the other hand, ghrelin treatment reversed these alterations (P < 0.05-P < 0.001) as well as elevating serum TNF-alpha levels significantly (P < 0.001). The findings of the present study suggest that alendronate induces oxidative gastric damage by a local irritant effect, and ghrelin ameliorates this damage by its possible antioxidant and anti-inflammatory properties.

繁殖豚における&lt;I&gt;Helicobacter&lt;/I&gt;属細菌の感染状況

Various methods were used to investigate the presence of Helicobacter infection in 50 sows slaughtered at the Sagamihara meat center from March to June 2000. The latex-agglutination method for the antibody against Helicobacter pylori produced a prevalence of Helicobacter-species infection of 76.7%, histopathological exami-nation of formalin-fixed gastric tissue using a Warthin Starry stain a prevalence of 50.0%, polymerase chain reac-tion using fresh gastric tissues a prevalence of 74%, and ELISA testing for the Helicobacter antigen using feces a prevalence of 44.9%. The prevalence of Helicobacter-species infection ranged from 40% to 100% of sows exam-ined depending on farm of origin.