UNLABELLED: ABSTRACT:

BACKGROUND: Chronic gastritis, peptic ulcer disease, and gastric cancer have been shown to be related to infection with Helicobacter pylori (H. pylori). Two major virulence factors of H. pylori, CagA and VacA, have been associated with these sequelae of the infection. In this study, total DNA was isolated from gastric biopsy specimens to assess the cagA and vacA genotypes.

RESULTS: Variations in H. pylori cagA EPIYA motifs and the mosaic structure of vacA s/m/i/d regions were analysed in 155 H. pylori-positive gastric biopsies from 71 individuals using PCR and sequencing. Analysis of a possible association between cagA and vacA genotypes and gastroduodenal pathogenesis was made by logistic regression analysis. We found that H. pylori strains with variation in the number of cagA EPIYA motif variants present in the same biopsy correlated with peptic ulcer, while occurrence of two or more EPIYA-C motifs was associated with atrophy in the gastric mucosa. No statistically significant relation between vacA genotypes and gastroduodenal pathogenesis was observed.

CONCLUSIONS: The results of this study indicate that cagA genotypes may be important determinants in the development of gastroduodenal sequelae of H. pylori infection. In contrast to other studies, vacA genotypes were not related to disease progression or outcome. In order to fully understand the relations between cagA, vacA and gastroduodenal pathogenesis, the mechanisms by which CagA and VacA act and interact need to be further investigated.

The Helicobacter pylori cagA gene encodes a cytotoxin which is activated by phosphorylation after entering the host epithelial cell. Phosphorylation occurs on specific tyrosine residues within EPIYA motifs in the variable 3'-region. Four different cagA EPIYA motifs have been defined according to the surrounding amino acid sequence; EPIYA-A, -B, -C and -D. Commonly, EPIYA-A and -B are followed by one or more EPIYA-C or -D motif. Due to observed discrepancies in cagA genotypes in cultured H. pylori and the corresponding DNA extracts it has been suggested that genotyping assays preferentially should be performed directly on DNA isolated from biopsy specimens. Gastric biopsies randomly selected from a Swedish cohort were homogenised and used for both direct DNA isolation and for H. pylori specific culturing and subsequent DNA isolation. In 123 of 153 biopsy specimens, the cagA EPIYA genotypes were in agreement with the corresponding cultured H. pylori strains. A higher proportion of mixed cagA EPIYA genotypes were found in the remaining 30 biopsy specimens. Cloning and sequencing of selected cagA EPIYA amplicons revealed variations in number of cagA EPIYA-C motifs in the mixed amplicons. The study demonstrates that culturing of H. pylori introduces a bias in the number of EPIYA-C motif. Consistent with other H. pylori virulence genotyping studies, we suggest that cagA EPIYA analysis should be performed using total DNA isolated from biopsy specimens.

BACKGROUND: Two main types of receptors for gastrin and cholecystokinin (CCK) have been cloned and identified. CCK1 (CCK-A) receptors are expressed in the pancreas, the gallbladder, and parts of the brain, while CCK2 (CCK-B/gastrin) receptors (CCK2R) are expressed in gastric glands and in most of the brain. A splice variant of the CCK2R designated CCKRi4sv (CCK-C), which is constitutively expressed in human pancreatic cancer cells, has also been described. The purpose of the present investigation was to study CCK2R, CCK2i4svR, and gastrin mRNA expression in human pancreatic adenocarcinoma on the assumption that co-expression of CCK2R and gastrin or constitutive CCK2i4svR mRNA expression plays a pivotal role in the progression of pancreatic cancer.

FINDINGS: PCR amplification using CCK2R specific primer-pairs, followed by ethidium-bromide stained agarose gel electrophoresis revealed the expression of wild-type CCK2R mRNA in 12 of 17 biopsy specimens. A CCK2R intron 4 specific nested PCR assay revealed that CCK2i4svR mRNA was expressed in only one of the biopsy specimen. The authenticity of PCR amplicons was confirmed by cloning of selected amplicons and DNA sequence analysis. Moreover, we found that hitherto undescribed multiple forms of 3'-end variant CCK2R mRNAs with various deletions in the retained intron 4 and exon 5, tentatively generating truncated proteins, were expressed in the pancreatic adenocarcinomas.

CONCLUSION: Cloning and DNA sequencing of selected amplicons revealed that CCK2R and multiple CCK2i4svR-like mRNAs are expressed in human pancreatic adenocarcinoma. The originally described CCK2i4svR mRNA was only expressed in one of 17 tumours and appears to be rarely expressed in pancreatic adenocarcinoma. We report that CCK2R- and gastrin mRNA co-expression may play a role in a portion, but not in all of these tumours, and that aberrant splicing takes places in these tissues generating multiple forms of 3'-end variant CCK2R mRNAs.

The tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC) is dynamic with an extensive interaction between the stroma and tumor cells. The aim for this study was to delineate the cross-talk between PDAC and cancer-associated fibroblasts (CAFs) with focus on the mechanism creating the chronic inflammatory tumor milieu. We assessed the effects of the cross-talk between primary PDAC and CAF cell lines on the creation and sustenance of the inflammatory tumor microenvironment in pancreatic cancer. The coculture of primary PDAC and CAF cell lines enhanced the levels of inflammatory factors including IL-1á, IL-6, CXCL8, VEGFA, CCL20, and COX-2. CAFs were superior to tumor cells regarding the production of most inflammatory factors and tumor cell associated IL-1á was established as the initiator of the enhanced production of inflammatory factors through the binding of IL-1á to the active IL-1 receptor (IL-1R1) expressed predominantly by CAFs. Furthermore, we found a positive correlation between IL-1á and CXCL8 expression levels in PDAC tissues and correlation between IL-1á expression and the clinical outcome of the patients. This confirmed an important role for the IL-1 signaling cascade in the creation and sustenance of a tumor favorable microenvironment. Neutralization of the IL-1á signaling efficiently diminished the cross-talk induced production of inflammatory factors. These data suggest that the cross-talk between PDAC cells and the main stroma cell type, i.e. CAFs, is one essential factor in the formation of the inflammatory tumor environment and we propose that neutralization of the IL-1á signaling might be a potential therapy for this cancer.

Introduction: Helicobacter pylori (H.pylori) infection is very common worldwide. A reliable diagnosis is crucial for patients with H.pylori related diseases. At follow-up it is important to confirm that eradication therapy has been successful. There is no established gold standard for the diagnosis of H.pylori infection.

Material and Methods: A sample of 304 volunteers from the general population was screened for H.pylori infection with serology, ¹³C-urea breath test (UBT), rapid urease test (RUT) on fresh biopsy, culture from biopsy and histological examination. Each method was tested against the other methods (except serology) taken together as gold standard.

Result: The sensitivity was 0.99 for serology 0.92 for UBT, 0.96 for RUT, 0.99 for culture and 0.95 for histological examination. Corresponding specificities were 0.82, 0.94, 0.93, 0.90 and 0.92, respectively. The accuracy was 0.86 for serology, 0.94 for UBT, 0.94 for RUT, 0.93 for culture and 0.93 for histology. There was a strong correlation between the results of UBT and histological scores for H.pylori colonization as well as between the results of UBT and the scores of RUT.

Conclusion: There were only minor differences in accuracy between three invasive tests for H.pylori infection in this population. RUT may be recommended as first choice since a result is obtained within hours. The accuracy of UBT was comparable to the invasive tests and it is recommended for situations when endoscopy is not needed.

Tumor microenvironment is composed of tumor cells, fibroblasts, and infiltrating immune cells, which all work together and create an inflammatory environment favoring tumor progression. The present study aimed to investigate the role of the desmoplastic stroma in pancreatic ductal adenocarcinoma (PDAC) regarding expression of inflammatory factors and infiltration of immune cells and their impact on the clinical outcome. The PDAC tissues examined expressed significantly increased levels of immunomodulatory and chemotactic factors (IL-6, TGF beta, IDO, COX-2, CCL2, and CCL20) and immune cell-specific markers corresponding to macrophages, myeloid, and plasmacytoid dendritic cells (DCs) as compared to controls. Furthermore, short-time survivors had the lowest levels of DC markers. Immunostainings indicated that the different immune cells and inflammatory factors are mainly localized to the desmoplastic stroma. Therapies modulating the inflammatory tumor microenvironment to promote the attraction of DCs and differentiation of monocytes into functional DCs might improve the survival of PDAC patients.

Background

The presence of various EPIYA tyrosine phosphorylation motifs in the CagA protein of Helicobacter pylori has been suggested to contribute to pathogenesis in adults. In this study, a unique PCR assay and sequencing strategy was developed to establish the number and variation of cagA EPIYA motifs.

Findings

MDA-DNA derived from gastric biopsy specimens from eleven subjects with gastritis was used with M13- and T7- sequence-tagged primers for amplification of the cagA EPIYA motif region. Automated capillary electrophoresis using a high resolution kit and amplicon sequencing confirmed variations in the cagA EPIYA motif region. In nine cases, sequencing revealed the presence of AB, ABC, or ABCC (Western type) cagA EPIYA motif, respectively. In two cases, double cagA EPIYA motifs were detected (ABC/ABCC or ABC/AB), indicating the presence of two H. pylori strains in the same biopsy.

Conclusion

Automated capillary electrophoresis and amplicon sequencing using a single, M13- and T7-sequence-tagged primer pair in PCR amplification enabled a rapid molecular typing of cagA EPIYA motifs. Moreover, the techniques described allowed for a rapid detection of mixed H. pylori strains present in the same biopsy specimen.

The aim of this research was to characterize the mucosa of the gastric cardia in relation to infection with Helicobacter pylori and the occurrence of chronic gastritis in other parts of the stomach in a sample of the general population. In this study, 80 adult volunteers underwent esophagogastroscopy with biopsies from the gastric cardia, corpus, and antrum. Gastritis was classified according to the Sydney system. Chronic gastritis (cardia excepted) was diagnosed in 35 subjects, 30 with H. pylori infection. Epithelial proliferative activity (Ki-67), p53- and p21 expression were examined quantitatively with cell counting after immunohistochemical stainings. Esophagitis was diagnosed macroscopically. Fourty eight subjects had cardia-type and 32 corpus-type mucosa in the anatomical cardia. The prevalence of esophagitis (nine cases) did not differ between these groups. Carditis was more prevalent among subjects with cardia-type mucosa (73 vs. 28%, P < 0.0001). H. pylori was present in 48% of those with cardia-type and 25% of those with corpus-type mucosa (P = 0.06). Of the 44 subjects with carditis, 31 had H. pylori in this location. The group with H. pylori infection had significantly higher mucosal proliferative activity when compared to uninfected subjects. Among the subjects with H. pylori-associated carditis, more p53-positive epithelial cells were detected compared to both the non-infected group (P = 0.0004) and to subjects with non-H. pylori-associated carditis (P = 0.03). In subjects with cardia-type mucosa, and both carditis and gastritis, the degree of chronic inflammation was higher in the cardia compared to the corpus and antrum and the p53 expression was significantly higher in the cardia compared to the corpus, but similar to that in the antrum. The proliferative activity was significantly higher in the antrum compared to the cardia and corpus, respectively. In conclusion, H. pylori infection, carditis, and increased p53 expression are more common in subjects with cardia- than corpus-type mucosa in the gastric cardia. Carditis is mainly related to H. pylori infection. There are some differences regarding inflammation, proliferative activity, and p53 expression between the cardia and other regions of the stomach, yet the significance of these differences remains to be clarified.

Background Homocysteine levels in circulation are determined by several factors and hyperhomocysteinemia is reportedly associated with cardiovascular diseases and dementia. The aim of this study is to determine the relation of chronic gastritis and other conditions to homocysteine levels and their relation to incident cardiovascular diseases and dementia. Methods An adult population-based cohort (N = 488) was screened for H. pylori infection, gastro-duodenitis ( endoscopic biopsies), disease history, and lifestyle factors. Blood samples were analyzed for pepsinogen I and II ( gastric function), vitamin B12, folate, homocysteine, and cystatin C ( renal function). The methylenetetrahydrofolate reductase C677T polymorphism reportedly associated with hyperhomocysteinemia was analyzed by pyrosequencing. Incident cardiovascular diseases and dementia were monitored during a median follow-up interval of 10 years. Results At baseline, there was a positive relation of S-homocysteine to male gender, age, S-cystatin C, methylenetetrahydrofolate reductase 677TT genotype and atrophic gastritis. During follow-up, cardiovascular diseases occurred in 101/438 and dementia in 25/488 participants, respectively. Logistic regression analysis ( adjusting for gender, age at baseline, follow-up interval, BMI, smoking, alcohol consumption, NSAID use, P-cholesterol, and P-triglycerides) showed an association of S-homocysteine higher than 14.5 mu mol/l to cardiovascular diseases (OR 2.05 [95% c.i. 1.14-3.70]), but not to dementia overall. Conclusions Gender, age, vitamin B12, folate, renal function, atrophic gastritis and the methylenetetrahydrofolate 677TT genotype were significant determinants of homocysteine levels, which were positively related to incident cardiovascular diseases.

The tumor microenvironment in pancreatic ductal adenocarcinoma (PDAC) is dynamic with an extensive interaction between the stroma and tumor cells. Our aim for this study was to delineate the cross-talk between PDAC and cancer-associated fibroblasts (CAFs) with focus on the mechanism creating the chronic inflammatory tumor milieu. We assessed the effect cross talk between primary PDAC and CAF cell lines propagated from tumors had on the creation and sustenance of an inflammatory environment and what factors that were involved in establishing the inflammation.

The coculture of PDAC and CAF cell lines, propagated from tumor tissues, enhanced the levels of inflammatory factors including IL-1α, IL-6, CXCL8, VEGFA, CCL20, and COX-2. The production of these factors correlated with the expression detected in vivo in PDAC tissues. The key producers of nearly all inflammatory factors were the CAFs and not the tumor cells.

IL-1α was produced by the tumor cell lines, whereas almost all IL-1RI was expressed by CAFs thus corresponding to their in vivo expression profile in PDAC tissues, indicating a role for the IL-1 signaling cascade in a tumor favorable microenvironment. Neutralization of the IL-1α pathway efficiently diminished the cross talk induced production of inflammatory factors, both in stroma and tumor cells. These data suggest that the cross-talk between PDAC cells and the main stroma cell type, i.e. CAFs, is one contributing factor in the formation of the inflammatory tumor environment and we propose that the neutralization of IL-1α pathway might be a potential therapy for this cancer.