Epithelial damage by Helicobacter pylori in gastric ulcers

Histopathology of gastric erosions. Association with etiological factors and chronicity

BACKGROUND

The histopathologic characteristics of the antral erosions, and a comparison with samples systematically collected from the background antral mucosa, have not been studied previously. Similarly, unknown is the association of these features with suspected etiological factors and chronicity of erosion.

MATERIAL AND METHODS

We studied 117 patients with gastric erosions in the absence of peptic ulcer disease. With 28 patients available for a follow-up 19 years later, sites of erosions and background mucosa were biopsied and histopathology of both independently assessed at both visits. Helicobacter pylori status was examined from the biopsies taken in the initial and follow-up gastroscopies. Only subjects originally displaying antral erosions were included. The presence of Herpes simplex virus (HSV) antibodies was analyzed and use of nonsteroidal anti-inflammatory drug (NSAID) was inquired.

RESULTS

  Initially, the inflammation was more active in the region of erosions than elsewhere in antral mucosa. More active inflammation in the erosion was associated with HSV seropositivity, Helicobacter pylori infection, and the recent use of NSAIDs. In the follow-up visit, antral erosions were present in 38% (3/8) of Helicobacter pylori negatives and in 35% (7/20) of positives (p = ns). The Helicobacter pylori positive subjects with chronic or recurrent erosions had initially higher scores of neutrophils compared to subjects with nonrecurrent or nonchronic erosions (2.7 ± 0.5 vs 1.2 ± 1.0; p = .002).

CONCLUSIONS

Focally enhanced inflammation is characteristic for gastric erosions. This focal inflammation was associated with HSV seropositivity or NSAID use suggesting that such inflammation may be important in the pathogenesis of gastric antral erosions. Highly active inflammation in the erosions associates with their chronicity.

Probiotic bacteria influence the composition and function of the intestinal microbiota

Probiotics have a range of proposed health benefits for the consumer, which may include modulating the levels of beneficial elements in the microbiota. Recent investigations using molecular approaches have revealed a human intestinal microbiota comprising over 1000 phylotypes. Mechanisms whereby probiotics impact on the intestinal microbiota include competition for substrates, direct antagonism by inhibitory substances, competitive exclusion, and potentially host-mediated effects such as improved barrier function and altered immune response. We now have the microbial inventories and genetic blueprints to begin tackling intestinal microbial ecology at an unprecedented level of detail, aided by the understanding that dietary components may be utilized differentially by individual phylotypes. Controlled intervention studies in humans, utilizing latest molecular technologies, are required to consolidate evidence for bacterial species that impact on the microbiota. Mechanistic insights should be provided by metabolomics and other analytical techniques for small molecules. Rigorous characterization of interactions between the diet, microbiota, and probiotic bacteria will provide new opportunities for modulating the microbiota towards improving human health.

Evolution of gastritis in patients with gastric erosions

OBJECTIVE

Gastric erosions are mainly associated with Helicobacter pylori infection and non-steroidal anti-inflammatory drugs (NSAIDs), but there has been no information available on the long-term evolution of gastritis in subjects with erosions.

MATERIAL AND METHODS

A series of 117 patients with gastric erosions without peptic ulcer disease and matched controls without erosions or ulcers were studied. Available subjects underwent endoscopy and biopsy 17 years later. Parietal cell antibodies were analysed at the first visit.

RESULTS

Fifty-two patients and 67 controls were available for follow-up. Since H. pylori was a major determinant of gastritis, only subjects with unchanged H. pylori status were included in the evaluation of gastritis progression. At the follow-up visit, gastric erosions were present in 38% (16/42) of the patients and 11% (5/46) of the controls (p=0.005). In H. pylori-negative subjects, no evolution of histological changes was seen. In H. pylori-positive subjects, body gastritis was initially less active in the erosion group. With time, antral gastritis worsened only in the erosion group. Parietal cell antibodies were more common in the control group (23%; erosion patients 0%; p=0.01), which also showed worsening of gastritis (p=0.003) and aggravation of atrophy (p=0.002) in the body mucosa.

CONCLUSIONS

Gastritis in H. pylori-positive subjects with gastric erosions shows evolution of antral predominance, body predominance including development of atrophic changes being rare. Accordingly, patients with erosions share the characteristics of gastritis of the duodenal ulcer phenotype. These findings support the importance of H. pylori and acid in the pathogenesis of gastric erosions in H. pylori-positive patients.

Molecular cloning and characterization of two Helicobacter pylori genes coding for plasminogen-binding proteins

Helicobacter pylori binds a number of host cell proteins, including the plasma protein plasminogen, which is the proenzyme of the serine protease plasmin. Two H. pylori plasminogen-binding proteins have been described; however, no genes were identified. Here we report the use of a phage display library to clone two genes from the H. pylori CCUG 17874 genome that mediate binding to plasminogen. DNA sequence analysis of one of these genes revealed 96.6% homology with H. pylori 26695 HP0508. A subsequent database search revealed that the amino acid sequence of a lysine-rich C-terminal segment of HP0508 is identical to the C terminus of HP0863. Recombinant proteins expressed from HP0508 and HP0863 bound plasminogen specifically and in a lysine-dependent manner. We designate these genes pgbA and pgbB, respectively. These proteins are expressed by a variety of H. pylori strains, have surface-exposed domains, and do not inhibit plasminogen activation. These results indicate that pgbA and pgbB may allow H. pylori to coat its exterior with plasminogen, which subsequently can be activated to plasmin. The surface acquisition of protease activity may enhance the virulence of H. pylori.

Helicobacter pylori-induced gastritis in experimentally infected conventional piglets

A conventional nonmutant animal that could be experimentally infected with Helicobacter pylori isolates would be a useful animal model for human H. pylori-associated gastritis. Gnotobiotic and barrier-born pigs are susceptible to H. pylori infection, but attempts to infect conventional pigs with this bacterium have been unsuccessful. In the present study, a litter of eight 20-day-old crossbreed piglets were purchased from a commercial farm. Six of them were orally challenged two to five times at different ages, between 29 and 49 days, with doses of H. pylori inoculum containing approximately 10(9) bacterial cells. Two animals served as controls. The inoculation program began 2 days postweaning when the piglets were 29 days of age. Prior to every inoculation, the piglets were fasted and pretreated with cimetidine, and prior to the first and second inoculation each piglet also was pretreated with dexamethasone. The challenged piglets were euthanasized between 36 and 76 days of age. H. pylori colonized all six inoculated piglets. The pathology of the experimentally induced gastritis was examined macroscopically and by light and electron microscopy. H. pylori induced a severe lymphocytic gastritis in the conventional piglets and reproduced the large majority of the pathologic features of the human disease. Therefore, the conventional piglet represents a promising new model for study of the various pathogenic mechanisms involved in the development of lesions of the human H. pylori-associated gastritis.

Epstein-Barr virus-associated gastric lymphomas are distinct from mucosa-associated lymphoid tissue-type lymphomas: genetic abnormalities of p53 gene

The authors studied 46 primary gastric lymphomas for expression of the p53 gene by immunohistochemistry and screened for mutations in p53 exon 5-8 by polymerase chain reaction-single strand conformation polymorphism. Twenty-five specimens cases were also analyzed for loss of heterozygosity (LOH) of chromosomal region 17p12-13.1. In 36 lymphomas negative for Epstein-Barr virus (EBV) infection, of which 29 were of mucosa-associated lymphoid tissue (MALT) type, p53 genetic changes were found in 47.2% but correlated poorly with overexpression. Only 20% of the mutations involved exon 7. There were recurrent mutations of intron 7, intron 6, and exon 6. In contrast, the 10 EBV-positive cases, none of MALT type, had a much higher rate of mutation, and all showed both p53 overexpression and p53 mutation and/or LOH, and 87.5% had mutations involving exon 7. Four of these involved codon 242, not seen in the EBV-negative group. Splicing mutations of intron 8 were seen in three specimens, two involving the same nucleotide position. In four of five specimens, LOH analysis identified microsatellite instability, allelic loss, or both. The Helicobacter pylori infection rate in the EBV-positive group (20%) was much lower than in the EBV-negative group (91.7%). These differences between the two groups suggest involvement of different carcinogens. Mutation of codon 242 has not been specifically associated with other tumors and may represent a mutational hot spot in the EBV-positive lymphomas.

Helicobacter pylori genotypes, host factors, and gastric mucosal histopathology in peptic ulcer disease

From 183 patients undergoing upper gastrointestinal endoscopy, we used antral and corpus gastric biopsies for bacterial culture and histopathologic examination, blood samples to detect immunoglobulin G antibodies against Helicobacter pylori, and H pylori genomic DNA to analyze cytotoxin-associated gene A (cagA) and vacuolating cytotoxin (vacA) genotypes. As expected, among H pylori biopsy-positive patients, those with duodenal ulcer (DU) (n = 34) had significantly more severe chronic and acute inflammation (P <.001) and epithelial degeneration (P =.004) in the gastric antrum than in the gastric corpus. Each of those 3 parameters and H pylori density were significantly higher in the antrum of patients with DU than in patients with gastric ulcer (GU) or no ulcer. Colonization with vacA s1/cagA-positive strains of H pylori was associated with inflammation and epithelial degeneration in gastric mucosa and increased risk for peptic ulcer disease (PUD), whereas colonization with vacA s2m2/cagA-negative strains was associated with mild gastric histopathology and was not associated with any significant risk for PUD. The predominant H pylori strains in African Americans were vacA s1bm1/cagA-positive, whereas all genotypes were well represented in non-Hispanic-Caucasians. By multivariate analysis, H pylori colonization was significantly associated with DU (Adjusted odds ratio [AdjOR] = 3.2 [1.4-7.2]) and nonsteroidal anti-inflammatory drugs (NSAID) use was inversely associated (AdjOR = 0.3 [0.2-0.7]). NSAID use (AdjOR = 4.3 [1.02-18.5]) and African-American ethnicity (AdjOR = 10.9 [2.6-50]) were significantly associated with GU. Smoking and age were not significantly associated with either DU or GU. These data indicate that DU is associated with an antral-dominant gastritis, and H pylori genotype and NSAID use independently contribute to the pathogenesis of PUD. HUM PATHOL 32:264-273. This is a US Government work. There are no restrictions on its use.

Expression of HLA-DR, costimulatory molecules B7-1, B7-2, intercellular adhesion molecule-1 (ICAM-1) and Fas ligand (FasL) on gastric epithelial cells in Helicobacter pylori gastritis; influence of H. pylori eradication

There is evidence that Helicobacter pylori infection up-regulates the expression of HLA class II molecules by gastric epithelial cells (GEC). In this study we evaluated whether GEC are capable of expression of costimulatory molecules in H. pylori gastritis. The expression of FasL by GEC, before and after eradication of H. pylori, was also studied. Thirty patients (23 men) aged 27-81 years (53.67 +/- 13.99 years (mean +/- s.d.)) with dyspepsia were studied. Upper gastrointestinal endoscopy was performed and six biopsies were obtained (antrum, n = 3; corpus, n = 3) for Campylobacter-Like Organisms (CLO) test and histology; 23 (16 men) were H. pylori+ and seven (all men) were H. pylori- by both methods and served as controls. Helicobacter pylori eradication therapy was given to H. pylori+ patients and all patients were re-endoscoped after 116 +/- 9 days. Formalin-fixed paraffin-embedded tissue sections were stained by the ABC immunoalkaline phosphatase method. In H. pylori gastritis HLA-DR was expressed and correlated with disease activity (P < 0.01). No HLA-DR was observed in controls. In H. pylori-eradicated patients significant decrease of HLA-DR was found (antrum, P < 0. 001). ICAM-1 was expressed by GEC in 80% of H. pylori+ patients; ICAM-1 expression did not correlate with gastritis parameters and decreased significantly after eradication (antrum, P < 0.01). B7-1 and B7-2 were expressed on H. pylori+ samples and their expression decreased after eradication, albeit not significantly. Weak epithelial expression of both B7 molecules was observed in all the controls. FasL was steadily expressed by GEC in both H. pylori+ and H. pylori- patients and remained almost unchanged after eradication. These findings suggest that GEC may acquire antigen-presenting cell properties in H. pylori infection through de novo expression of HLA-DR and costimulatory molecules. This seems to be attenuated after eradication and resolution of mucosal inflammation. The same cells exhibit the capacity to control the inflammatory process, probably by inducing apoptotic cell death to Fas-bearing infiltrating lymphocytes.

The histopathology of human gastric mucosa inhabited by Helicobacter heilmannii-like (Gastrospirillum hominis) organisms, including the first culturable case

The aim was to determine the prevalence of Helicobacter heilmannii-like organisms in human gastric biopsies and the associated histology compared with that of Helicobacter pylori-bearing gastric biopsies. Furthermore, the feasibility of culturing H. heilmannii was examined. A consecutive series of 727 gastric biopsies from 650 patients were prospectively scrutinized for H. heilmannii. Their distribution pattern was recorded as well as the affiliated morphology of the gastric mucosa. Additional biopsies from some of the patients were examined microbiologically. Four cases (0.6%)(95% confidence intervals: 0.01-1.2%) of the examined material harboured H. heilmannii. The bacterial burden was graded as sparse in three cases, moderate in one case. The distribution pattern was patchy; thus, in no case did all biopsies from one endoscopy comprise H. heilmannii. Adhesion to epithelial cells was infrequent. A mild gastritis, active in three cases, characterized all biopsies. Lymphoid aggregates occurred in biopsies from three patients. Micropapillary tufting of the epithelial layer and intestinal metaplasia were not apparent. Culture studies proved successful in the one of the four cases assayed. In conclusion the morphology of H. heilmannii-bearing mucosa deviates from that of H. pylori-associated mucosa by the absence of epithelial damage in the former. This observation can in part be explained by the predominant location of H. heilmannii at a distance from the epithelium in contrast to the conspicuous H. pylori adhesion to epithelial cells, coupled with a usually low bacterial burden and patchy occurrence of H. heilmannii as opposed to the generally more heavy infestation with H. pylori.

Helicobacter pylori infection delays the healing of acetic acid-induced gastric ulcer in Japanese monkeys

To clarify the relationship between Helicobacter pylori and the healing of gastric ulcers, we investigated the healing of acetic acid-induced gastric ulcers in the antral mucosa of Japanese monkeys (n = 5) infected with H. pylori and in control monkeys without H. pylori infection (n = 6). Using H. pylori-infected Japanese monkeys as an experimental model, gastric ulcers were induced endoscopically with acetic acid. Healing of ulcers and factors that influenced healing were studied. Continuous colonization with H. pylori was confirmed in the infected group throughout the observation period; no H. pylori were isolated from the gastric mucosa of the control group. White scarring was not observed in any infected monkeys 4 weeks after ulcer formation, but was observed in one (20%) of five monkeys at 6 weeks and in all five monkeys eight weeks after ulcer formation. In the control group, white scarring was observed in one (16.7%) of six monkeys at 4 weeks and in six monkeys at 6 (P < 0.01 vs infected group) and 8 weeks. The ammonia concentration of the gastric secretions and the grade of inflammation were significantly increased in the H. pylori-infected group compared with the control group (P < 0.01 and P < 0.001, respectively). The volume of intracellular PAS-positive substance was decreased (P < 0.025-0.01) at the ulcer margin in the infected group compared with the ulcer margin in the control group. The proliferation of gastric epithelial cells was markedly accelerated at the ulcer margin in the infected group compared with the ulcer margin in control group (P < 0.025-0.01). Our results strongly suggest that H. pylori infection delays the healing of gastric ulcers.

Sequence and expression of a candidate for the human Secretor blood group alpha(1,2)fucosyltransferase gene (FUT2). Homozygosity for an enzyme-inactivating nonsense mutation commonly correlates with the non-secretor phenotype

Synthesis of soluble A, B, H, and Lewis b blood group antigens in humans is determined by the Secretor (Se) (FUT2) blood group locus. Genetic, biochemical, and molecular analyses indicate that this locus corresponds to an alpha(1,2)fucosyltransferase gene distinct from the genetically-linked H blood group alpha(1,2)fucosyltransferase locus. The accompanying paper (Rouquier, S., Lowe, J. B., Kelly, R. J., Fertitta, A. L., Lennon, G. G., and Giorgi, D. (1995) J. Biol. Chem. 270, 4632-4639) describes the molecular cloning and mapping of two human DNA segments that are physically linked to, and cross-hybridize with, the H locus. We present here an analysis of these two new DNA segments. One of these, termed Sec1, is a pseudogene, because translational frameshifts and termination codons interrupt potential open reading frames that would otherwise share primary sequence similarity with the H alpha(1,2)fucosyltransferase. The other DNA segment, termed Sec2, predicts a 332-amino acid-long polypeptide, and a longer isoform, that share 68% sequence identity with the COOH-terminal 292 residues of the human H blood group alpha(1,2)fucosyltransferase. Sec2 encodes an alpha(1,2)fucosyltransferase with catalytic properties that mirror those ascribed to the Secretor locus-encoded alpha(1,2)fucosyltransferase. Approximately 20% of randomly-selected individuals were found to be apparently homozygous for an enzyme-inactivating nonsense allele (Trp143-->ter) at this locus, in correspondence to the frequency of the non-secretor phenotype in most human populations. Furthermore, each of six unrelated non-secretor individuals are also apparently homozygous for this null allele. These results indicate that Sec2 corresponds to the human Secretor blood group locus (FUT2) and indicate that homozygosity for a common nonsense allele is responsible for the nonsecretor phenotype in many non-secretor individuals.

Improvement of gastric inflammation and resolution of epithelial damage one year after eradication of Helicobacter pylori

AIMS

To investigate the effect of eradication of Helicobacter pylori infection on gastric epithelial damage and gastritis, scored according to the Sydney system.

METHODS

Gastritis scores and epithelial damage were assessed in gastric biopsy specimens before, and five weeks and one year after anti-H pylori therapy in 66 patients with H pylori related gastritis.

RESULTS

The mean initial levels of activity, inflammation, atrophy, intestinal metaplasia, and H pylori scores were higher in the antrum than in the corpus or fundus. Eradication of H pylori resulted in an improvement in the mean inflammatory score in antral biopsy specimens from 2.23 before treatment to 1.32 and 1.06, respectively, five weeks and one year after treatment. Corresponding values for fundic biopsy specimens were 1.30, 0.36 and 0.35. Activity scores improved from 1.41 before treatment to 0.13 and zero, respectively, five weeks and one year after treatment in antral biopsy specimens and from 0.60 before treatment to zero in fundic biopsy specimens. Before treatment, epithelial damage was present in 51% of biopsy specimens taken from the antrum and 23% of those from the corpus. Five weeks after eradication of H pylori none of the biopsy specimens revealed evidence of epithelial damage.

CONCLUSION

Eradication of H pylori is followed by a rapid, significant improvement in the gastritis score and resolution of epithelial damage in antral and fundic mucosa.

Histopathology of gastroduodenal inflammation: the impact of Helicobacter pylori

In this article the histological features of acute and chronic gastritis are reviewed. The histopathological gastric biopsy report can now encompass an aetiological, topographical (when antrum and corpus are sampled) and morphological comment on the gastric mucosa. The degree of detail included in the report (e.g. grading of the severity of inflammation, atrophy, density of Helicobacter pylori) will vary according to local requirement. However, the distinct recognisable patterns of inflammation categorised in the Sydney system provide a common terminology for a succinct diagnosis. The overall condition of the patient's gastric mucosa assigns him/her to one of the H. pylori-positive or negative categories of chronic gastritis. This may not only have relevance to current clinical management, but may be a valuable record if the patient returns with dyspeptic symptoms in the future. For example, duodenal ulcers are unlikely to develop except in patients with antrum predominant H. pylori-associated gastritis. Knowledge of the natural history of different types of gastritis is rapidly evolving, and the biopsy provides a permanent 'snapshot' of the state of the gastric mucosa at the time of the endoscopy.

Helicobacter pylori: the new bug on the (paraffin) block

A nameless spirillar organism in search of a disease only a few years ago, Helicobacter pylori has seen its fortunes suddenly reversed. After a rapid succession of name changes and some acrimonious disputes across continents, in less than a decade H. pylori has been catapulted to the centre stage of gastroenterological and microbiological research and has topped the most-wanted list of the pharmaceutical industry. The discovery of H. pylori has provided the momentum for the formation of the group that eventually created the Sydney System. Today, H. pylori is increasingly recognized as one of the most prevalent human pathogens worldwide. Its causal association with chronic active gastritis is undisputed and its role in the pathogenesis of peptide ulcer disease, although still poorly understood, is universally accepted. Furthermore, possible connections between chronic H. pylori infection and gastric carcinoma and primary gastric lymphoma are now being explored with increasing alacrity. With a few notable exceptions, pathologists have remained passive spectators of these exciting discoveries and have allowed gastroenterologists and microbiologists to set the pace in the quest for the determinants of gastritis, peptic ulcer and gastric cancer. This article is intended to outline some of the accepted facts on the development, progression, and pathology of H. pylori gastritis and to pose questions about this elusive infection. The authors hope that it might also contribute to stimulate further research, particularly on those aspects that are eminently suited to be addressed by pathologists.

Gastritis: terminology, etiology, and clinicopathological correlations: another biased view

The histological approach to gastritis, especially the chronic forms, has undergone a series of re-evaluations by different experts over the past decade, mainly because of the recognition of individual disease patterns that have specific clinical and epidemiological implications. The most spectacular of these was the discovery of Helicobacter pylori and its common gastritis, its relation to almost all duodenal peptic ulcers and to most gastric peptic ulcers, its potential as a precursor of first multifocal atrophic gastritis and later tubule-forming gastric carcinomas, and its status as a cause of gastric mucosal lymphomas. During this same decade other classes of gastric reaction and inflammations have been recognized, including chemical injury and lymphocytic gastritis. Also in the same decade the importance of non-steroidal anti-inflammatory drugs (NSAIDs) has emerged as a cause of gastric mucosal injuries. To add emphasis to all these discoveries, biopsies are being performed on stomachs in almost epidemic numbers and each biopsy specimen has the potential of having the features of one or more of these injuries as well as injuries that have yet to be described. To cope with this rapidly expanding gastric inflammatory informational extravaganza, pathologists need some way of dealing with the various entities comfortably and some method of cataloging them in ways that are understandable both to them and to the endoscopists with whom they work. However, if emerging data about the chronic gastritides are correct, it is conceivable that the need to diagnose them, from a strictly clinical standpoint, is limited. Either we may know what is in the biopsy specimen before we see it or what we see may not be important, although it may be intellectually challenging.

Gastric adenocarcinoma with ciliated tumor cells

Ciliated metaplasia (CM) of gastric mucosa is common in Japanese individuals but rare in whites. We studied 36 consecutive gastrectomies from Chinese individuals for the presence of CM. The gastrectomies were performed for adenocarcinoma (n = 22), benign ulcer (n = 13), and malignant lymphoma (n = 1). Ciliated metaplasia was found in 16 (44.4%) of the stomachs, with equal distribution between male and female patients. Ciliated metaplasia was present in 11 cases (50%) of adenocarcinoma and in five cases (38.5%) of benign ulcer, the difference being statistically insignificant. Contrary to previous studies, there was no increased frequency of CM in gastric mucosa harboring an intestinal-type adenocarcinoma compared with those with non-intestinal-type tumors. Ciliated metaplasia always co-existed with intestinal metaplasia. Colonization by Helicobacter pylori was not associated with an increased incidence of CM. In five cases (22.7%) of adenocarcinoma ciliated tumor cells were found, and all of these cases showed CM in the gastric mucosa. In one of these cases the whole tumor was composed of glands formed by ciliated cells. In the other cases there was a morphologically different nonciliated component. The cilia in the tumor cells showed light microscopic and ultrastructural changes identical to those of the cilia seen in CM affecting the nonneoplastic gastric mucosa. This study documents for the first time the co-existence of CM and ciliated adenocarcinoma in the same stomach. It is concluded that in the Hong Kong Chinese population CM is commonly present in gastric mucosa harboring an adenocarcinoma or benign ulcer. Adenocarcinomas with ciliated cells are strongly associated with CM.

Modes of Helicobacter colonization and gastric epithelial damage

A total of 144 gastric biopsies colonized by Helicobacter-like organisms were studied under light and differential interference contrast microscopy for the modes of bacterial colonization. Biopsies were also graded for the degree of epithelial damage (epithelial-damage-grade: 0 to 6, in ascending order of severity) and density of Helicobacter-like organism (Helicobacter-grade: 0 to 6, in ascending order of bacterial density). Three modes of colonization were identified: free-in-mucus, surface-adhesion and intercellular colonization. Because light microscopy cannot definitely prove the presence of intracellular colonization, bacteria located between cells and below the apical cell border were counted together as intercellular colonization. Bacteria free-in-mucus were seen in all biopsies. Surface adhesion was seen in 50-87.9% of biopsies, without obvious correlation with the epithelial-damage- and Helicobacter-grades. The incidences of intercellular and intracellular colonization were directly proportional to the epithelial-damage- and Helicobacter-grades. Free-in-mucus as the predominant mode of colonization was mainly seen in biopsies with lower (1-3) epithelial-damage- and Helicobacter-grades. Conversely, biopsies with intercellular colonization as the predominant mode of colonization were mainly cases with higher (4-6) epithelial-damage- and Helicobacter-grades. In cases showing predominantly bacteria between cells, 69.2% had a gastric ulcer whereas only 38.8% of cases showing predominantly bacteria free-in-mucus showed ulceration (P < 0.01). These results indicate that Helicobacter-like organisms can invade and penetrate between epithelial cells. When free-in-mucus, Helicobacter-like organisms are less likely to induce epithelial damage. However, the more invasive modes of colonization (intercellular) were associated with severe epithelial damage and high Helicobacter density.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathologic changes of gastric mucosa colonized by Helicobacter pylori

One hundred eighty-nine consecutive gastric biopsies showing colonization by Helicobacter pylori (HP) were studied. Epigastric pain and bleeding were the clinical presentations in 167 cases (88.4%). Major endoscopic findings were gastritis (n = 72, 38.1%) and ulceration (n = 101, 53.4%). Duodenal ulcer was associated with 32 (44.4%) and 29 (28.7%) cases of gastritis and gastric ulcer, respectively. Histologically, the HP-colonized gastric epithelium showed characteristic degenerative changes that were topographically related to the bacteria but unrelated to the inflammatory infiltrate. Disintegration and loss of apical mucus with formation of epithelial pits was seen in nearly all cases. Other changes included microerosion, conventional erosion, and frank ulceration. Only the disintegration of apical mucus, epithelial pit, and microerosion were specific for HP colonization. These conditions were absent in areas not colonized by HP and in 79 consecutive HP-negative gastric biopsies seen during the same study period. The epithelial degenerative changes in HP-colonized gastric mucosa are easy to recognize in routine hematoxylin-eosin-stained sections and they could serve as histologic guides to the localization of the bacteria. It is proposed that HP-colonized gastric mucosa is a distinct pathologic entity with a pathologic spectrum ranging from active chronic gastritis to erosion and frank ulcer. Damage to the mucin-containing portion of the gastric epithelial cells appears to be the basic cytopathologic effect of HP on the gastric mucosa. As effective specific treatment for HP infection is available, identification of HP colonization in gastric biopsies should be attempted in all cases of gastritis and gastric ulcer.