Helicobacter felis infection is associated with lymphoid follicular hyperplasia and mild gastritis but normal gastric secretory function in cats

No significant association between non-Helicobacter pylori Helicobacter infection with gastritis-related indices and gastric cancer

BACKGROUND

Non-Helicobacter pylori Helicobacter (NHPH) has recently been linked to various gastric diseases. However, the relationship between NHPH infection and gastric cancer remains controversial. This study aimed to identify the effect of NHPH infection on gastritis and gastric cancer development.

MATERIALS AND METHODS

Formalin-fixed paraffin-embedded tissues were obtained from 73 patients with gastric cancer, of whom 21 cases were Helicobacter pylori (Hp) current infection, 37 cases were Hp previous infection, and 15 cases were Hp naïve infection, and were screened for NPHPs using polymerase chain reaction. The results were compared with NHPH infection rates in the patients with gastritis-related diseases reported in the previous study. We evaluated the association of NHPH infection with gastritis and clinicopathological features of gastric cancer.

RESULTS

NHPH infection rates were 4/21 (19%) in "Hp current" patients, 4/37 (11%) in "Hp previous" infection patients, and 1/15 (7%) in "Hp naïve" patients, showing no significant difference in infection rates based on Hp infection status. NHPH infection rates in gastric cancer patients were similar to those in the patients with gastritis-related diseases reported in the previous study. A comparison of NHPH-positive and negative patients showed no significant differences in atrophic gastritis status, serum gastritis markers, or clinicopathological characteristics of gastric cancer, such as localization, size, gross type, differentiation, or depth.

CONCLUSIONS

The association between gastric cancer and NHPH infection would have important implications for gastric cancer prevention, diagnostics, and treatment, however, no significant association was found in this particular population.

Treatment of acquired pyloric stenosis via Y-U pyloroplasty in a Burmese cat

Case summary

An 11-year-old female spayed Burmese cat was presented for chronic intermittent vomiting. Previous medical and dietary treatments were unsuccessful. Endoscopically, a narrow pyloric outlet was found and Y-U pyloroplasty was performed. The clinical signs disappeared postoperatively after treatment with a proton pump inhibitor and dietary management.

Relevance and novel information

This is the first case report of feline-acquired pyloric stenosis with documented histopathological findings from a full-thickness biopsy of the pyloric sphincter. In addition, this is the first case of Y-U pyloroplasty being conducted in a cat. The histopathological findings might help explain the pathogenesis of this disorder in cats.

Hyperplastic and fibrosing gastropathy resembling Ménétrier disease in a cat

Case summary

A 3.5-year-old domestic shorthair cat presented with a 6 month history of weight loss and polyphagia. Clinical examination revealed a markedly reduced body condition score (2/9) and a quiet demeanour. Laboratory abnormalities comprised a mild non-regenerative anaemia, stress leukogram, hypoproteinaemia due to hypoalbuminaemia, azotaemia, hypokalaemia, total hypocalcaemia and sub-maximally concentrated urine (specific gravity 1.020). Abdominal ultrasonography revealed marked thickening of the gastric mucosa within the fundus, body and pylorus; the most dorsal portion of the fundus was spared. The thickened mucosa contained multiple small, anechoic cyst-like structures. The gastric submucosa, muscularis and serosa appeared normal. Histopathology, performed on a full-thickness gastric biopsy, revealed mucosal hypertrophy and markedly dilated gastric glands in areas; not all gastric glands were affected, with some appearing normal or atrophic. Focal interstitial fibrosis was present in some areas. The findings of hypoproteinaemia, gastric ultrasonographic changes and histopathology results share several similarities to those reported with Ménétrier disease.

Relevance and novel information

Ménétrier disease is a rare condition of the stomach in humans. A similar condition, giant hypertrophic gastritis (or Ménétrier-like disease), has also been described rarely in dogs. To our knowledge, Ménétrier-like disease has not been previously described cats. This case shares features of Ménétrier-like disease, raising the suspicion of a similar aetiopathogenesis.

Helicobacter suis infection is associated with nodular gastritis-like appearance of gastric mucosa-associated lymphoid tissue lymphoma

Most patients with gastric mucosa‐associated lymphoid tissue (MALT) lymphoma are infected with Helicobacter pylori, and eradication therapy is the first‐line treatment for localized disease with H pylori infection. However, there were several reports showing effectiveness of eradication therapy in even H pylori negative cases. Gastric MALT lymphomas are endoscopically classified into three common types: superficial, ulcerative, and elevated types. For the past 20 years, we have encountered 200 cases of localized gastric MALT lymphoma. Among them, only 4 cases (2%) showed similar macroscopic findings to those of nodular gastritis (gastric MALT lymphoma with nodular gastritis‐like appearance; M‐NGA). Here, we compared clinicopathological characteristics and prevalence of non‐H pylori Helicobacter (NHPH) infection between M‐NGA and other common types of gastric MALT lymphoma. To examine the prevalence of NHPH infection, DNA was extracted from formalin‐fixed paraffin‐embedded biopsy tissues from four cases of M‐NGA, 20 cases of common endoscopic types of gastric MALT lymphoma, and 10 cases of nodular gastritis. We used a highly sensitive polymerase chain reaction assay to detect the presence of five species of NHPH (Helicobacter suis, H felis, H bizzozeronii, H salomonis, and H heilmannii). H suis infection was detected in 4, 2, and 0 of the 4, 20, and 10 cases of M‐NGA, other types of gastric MALT lymphoma, and nodular gastritis, respectively. Other NHPH species were not detected in any cases. Complete response rate by eradication therapy was 4/4 in M‐NGA cases. Therefore, nodular gastritis‐like MALT lymphoma, which shows a very rare phenotype, is closely associated with NHPH infection, and eradication therapy may be the first‐choice treatment.

Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

BACKGROUND

Low-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions.

RESULTS

A total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract.

CONCLUSIONS

The pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine.

Effect of gastric acid-suppressive therapy and biological variation of serum gastrin concentrations in dogs with chronic enteropathies

BACKGROUND

Serum gastrin concentration can help diagnose gastrinomas in dogs if >3-10× the upper reference limit (URL), but antisecretory therapy and other conditions can also cause hypergastrinemia. Effects of antisecretory therapy (famotidine or ranitidine, omeprazole) on serum gastrin concentration in dogs with chronic enteropathy (CE) and its biological variation (BV) are unknown. Aim of the study was to evaluate serum gastrin in acid-suppressant-treated or -naïve CE dogs; test the association between serum gastrin and histopathologic findings in acid-suppressant-naïve CE dogs; and evaluate the BV of serum gastrin in dogs not receiving any gastric acid suppressive therapy. Samples from 231 dogs were used and serum gastrin was measured by chemiluminescence assay. Gastric and duodenal histologic lesions were evaluated and graded. BV of serum gastrin was evaluated in serial samples.

RESULTS

Serum gastrin concentrations were significantly higher in acid-suppressant-treated than acid-suppressant-naïve dogs (P = 0.0245), with significantly higher concentrations in proton pump inhibitor (PPI)- than H2-antihistamine-treated patients (P = 0.0053). More PPI- than H2-antihistamine-treated dogs had gastrin concentrations above URL (P = 0.0205), but not >3× nor >10× the URL. Serum gastrin concentrations correlated with the severity of gastric antral epithelial injury (P = 0.0069) but not with any other lesions or the presence/numbers of spiral bacteria in gastric biopsies. Intra- and inter-individual BV were 43.4 and 21.6%, respectively, in acid-suppressant-naïve dogs, with a reciprocal individuality index of 0.49 and a critical difference of ≥29.5 ng/L.

CONCLUSIONS

Antisecretory (particularly PPI) treatment leads to hypergastrinemia in CE dogs, but the concentrations seen in this study are unlikely to compromise a diagnosis of gastrinoma. Use of a population-based URL for canine serum gastrin and a URL of ≤27.8 ng/L are appropriate.

A mixed population of Helicobacter pylori, Helicobacter bizzozeronii and "Helicobacter heilmannii" in the gastric mucosa of a domestic cat

Background

The presence of Helicobacter within the gastric mucosa is responsible for producing pathology in many animal species, including man. Since humans have been shown to harbour many of the same bacterial species as domestic carnivores, concern over their zoonotic potential has been growing. Helicobacter pylori, a class 1 carcinogen responsible for cases of gastritis and gastric cancer in humans, produces similar pathology in pet carnivores and is considered an example of anthroponosis. The case here presented refers to a 13 year-old mixed breed spayed female cat seen at necropsy.

Findings

Stomach samples were analysed for the presence of Helicobacter spp. by cytology, histopathology and PCR. Mild mucosal atrophy was observed in the fundus and antrum, while lymphoplasmocytic infiltrates where noted in the lamina propria of the antrum. Helicobacter-like organisms were observed in the corpus and antrum, occupying gastric glands and surface mucosa. It was possible to detect Helicobacter spp., H. pylori, H. heilmannii and H. bizzozeronii in the fundus, corpus and antrum by PCR, while in the antrum PCR samples were positive for H. pylori.

Conclusions

The spayed female under study could represent either a yet un-described population of domestic cats infected with H. pylori or a case of anthroponosis.

Gastric Helicobacter spp. in animal models: pathogenesis and modulation by extragastric coinfections

Animal models are used to study complex host, microbial, and environmental influences associated with gastric Helicobacter infection. Evidence that gastric helicobacters are pathogenic in animals first came from ferrets. Felids, nonhuman primates, and many other species also harbor stomach helicobacters. Today, mice are preferred by most researchers for scientific investigation because of cost-efficiencies, rapid reproduction, choice of laboratory reagents, and availability of genetically engineered models. Infection with Helicobacter felis or H. pylori Sydney strain-1 in appropriate mouse strains produces disease with remarkable similarities to H. pylori in humans. Due to recent advances in genetic engineering, in vivo imaging, and system-wide genomics and proteomics, these models will become even more widespread in the future. Recently, it has been shown that extragastric infections can dramatically affect the severity of disease induced by gastric Helicobacter spp. through heterologous immunity. These models provide proof-of-principle for the "African enigma" wherein gastric cancer is underrepresented in low-lying tropical countries with concurrently high H. pylori and internal parasite prevalence. Helicobacter gastritis and carcinogenesis in mouse models may be augmented or ameliorated by other infectious agents depending on the character of the invoked immune response. Knowledge gained from the Human Microbiome Project and other investigations is certain to shed new light on the influence of extragastric bacterial, viral, fungal, and parasitic coinfections on H. pylori-associated peptic ulcer disease and gastric adenocarcinoma.

Helicobacter spp. in cats: association between infecting species and epithelial proliferation within the gastric lamina propria

The aim of this study was to determine whether there is an association between Helicobacter spp. infection of the feline stomach and the presence of gastric lesions and epithelial proliferation within the mucosa of this tissue. The study included 23 pet cats of both sexes and of varied age and breed. Eighteen of these animals were clinically normal and five had a history of chronic vomiting. Samples of the mucosa of the pyloric antrum, corpus and fundus were collected by gastroscopy. The presence of Helicobacter spp. was confirmed by polymerase chain reaction (PCR) or Warthin-Starry (WS) staining and the species of Helicobacter was determined by PCR. Mucosal lesions were evaluated by examination of sections stained by haematoxylin and eosin (HE) and epithelial proliferation was determined by enumerating nucleolar organizer regions (AgNOR). In 20 (87%) cats the presence of Helicobacter spp. was confirmed by both PCR and WS. There was no significant difference in colonization density between the different gastric regions. H. heilmannii was the most frequently identified species (17 of 20 cats), and H. felis was only identified in co-infection (two of 17 cats). One sample that was PCR positive to the genus level for Helicobacter spp. was negative for the four individual species reactions. Histological changes in the lamina propria included mild mononuclear inflammatory infiltration, the presence of lymphoid follicles, fibrosis and glandular degeneration. These changes were most severe in the pyloric antrum. There was significant association between infection with gastric Helicobacter spp. and the presence of lymphoid follicles (P=0.03), and between infection and epithelial proliferation in the antrum (P<0.01), corpus (P<0.001) and fundus (P<0.001).

Survey of Helicobacter infection in domestic and feral cats in Korea

Discovery of Helicobacter (H.) pylori has led to a fundamental change in our understanding of gastric diseases in humans. Previous studies have found various Helicobacter spp. in dogs and cats, and pets have been questioned as a zoonotic carrier. The present study surveyed the Helicobacter infections and investigated the presence of H. felis and H. pylori infections in domestic and feral cats in Korea. Sixty-four domestic cats and 101 feral cats were selected from an animal shelter. Saliva and feces were evaluated by Helicobacter genus-specific polymerase chain reaction (PCR). Genus-specific PCR positive samples were further evaluated for H. felis and H. pylori using specific primer pairs. Thirty-six of 64 (56.3%) samples from domestic cats and 92 of 101 (91.1%) samples from feral cats were PCR positive; the positive rate of feces samples was higher than that of saliva samples in both groups. H. felis and H. pylori species-specific PCR was uniformly negative. The prevalence of Helicobacter spp. in feral cats was approximately two-fold higher than that of domestic cats. The fecal-oral route may be more a common transmission route not only between cats but also in humans.

Muc1 limits Helicobacter felis binding to gastric epithelial cells but does not limit colonization and gastric pathology following infection

BACKGROUND

The mucin Muc1 is constitutively expressed by the gastric mucosa and is likely the first point of direct contact between the host stomach and the adherent pathogens. The expression of Muc1 has been shown to limit colonization of mice by Helicobacter pylori, known to adhere to the gastric epithelium, as well as associated pathology. However, the potential role of this mucin against nonadherent Helicobacter has not been previously studied. We therefore examined the importance of Muc1 on the pathogenesis of Helicobacter felis, believed not to adhere to the murine mucosa.

METHODS AND RESULTS

Using primary cell cultures, we found that H. felis can bind gastric epithelial cells in vitro, and adherence to epithelial cells deficient in Muc1 was increased compared to controls that expressed the mucin. However, following infection of deficient mice, we found that Muc1 did not impact on H. felis colonization or pathogenesis in vivo, in contrast to previous observations with H. pylori.

CONCLUSIONS

This demonstrates a variable effect of Muc1 on protection against closely related adherent and nonadherent Helicobacter species, and supports a key role for Muc1 in limiting attachment of adherent bacteria to the gastric mucosal surface.

Gastric Helicobacter species as a cause of feline gastric lymphoma: a viable hypothesis

Gastric Helicobacter spp. are associated with chronic inflammation and neoplastic transformation in humans as well as domestic and laboratory species. The present study examined the association of Helicobacter heilmannii (Hhe) infection in pet cats with feline gastric mucosa associated lymphoid tissue (MALT) lymphoma. Tissues were collected via gastric biopsy or at necropsy from 47 pet cats with clinical signs of gastrointestinal disease, including vomiting and inappetance, and classified as gastritis (14/47), lymphoma (31/37), or normal (2/47). Tissues positive for argyrophilic organisms with Warthin-Starry stain (29/47) were assessed by fluorescent in situ hybridization (FISH) for the presence of Hhe strains 1-4 as well as with a fifth probe that detected Helicobacter salomonis, Helicobacter bizzozeronii, or Helicobacter felis. A significant association of positive Warthin-Starry status with Hhe infection was found in cases of sick cats (22/29; p<0.05 by Chi-square; chi(2)=7.034). Interestingly, a significant association between Hhe status and a diagnosis of lymphoblastic or lymphocytic lymphoma was observed as well in a subset of 24 Warthin-Starry positive lymphoma cases: of lymphoblastic lymphoma cases, 13/17 were positive for Hhe (p<0.05; chi(2)=4.854). Hhe strains 2 and 4 were most commonly found (18/29 and 17/29, respectively) among sick cats, although a higher than expected number of cats was also positive for Hhe1, which initial reports have described as rare in cats and common in humans. The association found between a positive Hhe status with the presence of feline gastric lymphoma, especially lymphoblastic lymphoma, argues for the need to conduct prospective studies to better identify the frequency and strain distribution of Hhe infection in both healthy and clinically ill cats, particularly those cats with gastric lymphoma.

Immunogenicity and pathogenicity of Helicobacter infections of veterinary animals

The initial discovery that the human stomach is commonly infected by the bacterium Helicobacter pylori subsequently resulted in the identification of a whole new family of pathogenic bacteria. In less than 25 years, the Helicobacter genus has grown from obscurity to number at least 38 different species with many more awaiting classifications. These bacteria, many of which are either direct or opportunistic pathogens, are present in virtually every mammalian species examined, and have also now been identified in a number of birds. The pathogenesis associated with these infections is predominantly the result of a chronic inflammatory response mounted by the host against the infection. This is typically a Th1-driven response which can result in a range of conditions from hepatitis, through gallstones to cancer. In some cases the inflammatory response to these infections is normally well managed by the host and disease only results when there is a breakdown or misbalance in the immunoregulatory process, which for example can result in inflammatory bowel disease in experimental models. Understanding the disease association and pathogenic mechanisms of the different Helicobacter infections is clearly of potential significance not only from an animal welfare point of view but also from the growing realisation of how commonly transmission of Helicobacter occurs between different mammals, including pathogenic zoonotic infections of humans.

Gastric adenocarcinoma and chronic gastritis in two related Persian cats

Two 12.5-year-old castrated male Persian cats from the same household, whose dams were littermates, presented simultaneously with gastric adenocarcinoma associated with proliferative and fibrosing gastritis. Intralesional adult Ollulanus tricuspis nematodes and rare surface-associated spiral-shaped bacteria were identified in one cat. No etiologic agents were identified in tissues from the second cat; however, gastric mucosa was examined following anthelmintic treatment. Clinical signs in each cat had commenced 2 months apart and included vomiting, hematemesis, intermittent melena, and weight loss. This is the first report of gastric adenocarcinoma occurring in housemate cats or cats of common descent. Carcinogenesis may have been influenced by shared undetermined genetic and environmental factors, possibly including Ollulanus tricuspis, spiral-shaped bacteria, or other etiologies for chronic gastritis that remain unidentified.

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori infection

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

Molecular methods to distinguish reactive and neoplastic lymphocyte expansions and their importance in transitional neoplastic states

Although lymphoma and leukemia usually can be diagnosed by routine cytology and histology, some cases present a diagnostic challenge for pathologists and clinicians. Often the dilemma lies in determining whether a population of lymphocytes is reactive or neoplastic. We review currently available methods for analyzing lymphocyte populations by immunophenotyping and by identifying clonally rearranged immunoglobulin and T-cell receptor genes and discuss how these tests can be used to clarify such diagnostic dilemmas. We also describe the detection of chromosomal abnormalities and methods on the horizon, such as gene expression profiling, to identify diagnostically useful oncogenes. Finally, we review the emerging concept of transitional neoplastic states, in which reactive lymphocytes transform to neoplastic lymphocytes in the presence of continued antigenic stimulation, such as that caused by infection with Helicobacter pylori. The existence of transitional neoplastic states underscores the need for an array of molecular diagnostic tools that would improve our ability to characterize lymphocyte populations in human and animal patients and enhance early detection of neoplastic lymphocytes such that eradication of the infectious or inflammatory stimulus could lead to cure.

Putative effect of Helicobacter pylori and gastritis on gastric acid secretion in cat

Helicobacter pylori may increase or inhibit gastric acid. We studied acid variations and plasma gastrin in cats harboring Helicobacter felis, harboring H. pylori, or free of gastric pathogens with reference to thioperamide (H(3) receptor antagonist) and SR-27417A (PAF receptor antagonist). In cats harboring H. felis, gastric mucosa were histologically normal. After H. felis eradication, pentagastrin-stimulated acid secretion was increased (40%) compared with the situation before eradication. Thioperamide abolished this inhibitory effect of H. felis, whereas SR-27417A did not. Basal and meal-stimulated plasma gastrin levels were not affected by eradication therapy. Acid secretion was inhibited (-80%) in week 3, increased from weeks 5 to 9, and remained constant for up to 42 weeks after H. pylori infection. SR-27417A had no effect on acid secretion before week 8 but inhibited it thereafter, and thioperamide increased it (20%) only before week 7 in those cats. Helicobacter inhibits gastric acid via an H(3) receptor pathway. Inflammatory mediators are thus involved in adaptation to the inhibitory effects of H. pylori on acid secretion.

Fatal gastrointestinal infection with 'Flexispira rappini'-like organisms in a cat

A 4-month-old male British Blue cat with catarrhal to haemorrhagic enteritis showed massive colonization of the stomach, small intestine and caecum with spiral-shaped bacilli. In the stomach, organisms were located in foveolae and gland lumina and within unaltered and degenerate epithelial cells. Inflammatory infiltration was moderate and T cell dominated. In the intestine, bacilli were found in the gut lumen, berween villi, in crypt lumina and within epithelial cells. Degeneration of crypt epithelial cells as well as crypt dilation and moderate to massive macrophage-dominated infiltration of the mucosa and submucosa were observed. Immunohistochemically, bacilli were positive with an antibody against Helicobacter. Ultrastructurally, the organisms strongly resembled 'Flexispira rappini', a spiral-shaped Helicobacter species known as a normal intestinal colonizer in dogs and mice.

Helicobacter spp. infection in cats: evaluation of the humoral immune response and prevalence of gastric Helicobacter spp

The principal aims of this study were to evaluate the humoral immune response (IgG) of cats with gastric Helicobacter spp. infection, and to determine the prevalence of different types of Helicobacter spp. in the stomachs of cats. The Helicobacter infection status of 45 cats (12 healthy spay/neuter cats, 9 sick cats, 24 colony cats) was determined by evaluating endoscopic gastric biopsies for urease activity, presence of Helicobacter-like organisms (HLO) on histopathology, and genus and species-specific PCR. Serum samples were evaluated with a kinetic enzyme linked immunosorbent assay (ELISA) utilizing the high molecular cell-associated protein (HM-CAP) fraction of H. felis ATCC 49179.Seventeen of 45 cats were infected with Helicobacter spp.: "H. heilmannii" 9/17, H. felis 4/17, mixed "H. heilmannii" and H. felis 3/17, unclassified-Helicobacter spp. 7/17. H. pylori was not detected in any cat. Kinetic ELISA results were significantly higher for infected cats, than for uninfected cats. Cats infected with different Helicobacter spp. showed similar distribution of OD/min values. There were no effects of age or clinical signs on the results of kinetic ELISA. No correlation between colonization density and seroconversion was observed. There were statistically significant, but weak correlations between the degree of seroconversion and the degree of inflammation, and the number of lymphoid follicles. Infected cats had more severe inflammation in the pylorus and fundus than uninfected cats. Infected sick cats had a higher degree of pyloric, but not fundic inflammation, than healthy infected cats and uninfected sick cats. The results indicate that naturally acquired infection with gastric Helicobacter spp. is associated with seroconversion (IgG) in cats. The similar ELISA values in cats infected with a variety of Helicobacter spp. suggests substantial antigenic homology between different Helicobacter spp. The higher degree of inflammation in infected than uninfected cats, supports a role for Helicobacter as a cause of gastritis in cats.

Helicobacter pylori infection in the cat: evaluation of gastric colonization, inflammation and function

BACKGROUND

Further elucidation of the consequences of Helicobacter pylori infection on gastric mucosal inflammation and gastric secretory function would be facilitated by an animal model that is susceptible to infection with H. pylori, is broadly similar in gastric physiology and pathology to people, and is amenable to repeated non-invasive evaluation. The goal of this study was to examine the interrelationship of bacterial colonization, mucosal inflammation and gastric secretory function in cats with naturally acquired H. pylori infection.

MATERIALS AND METHODS

Twenty clinically healthy cats with naturally acquired H. pylori infection (cagA-, picB) and 19 Helicobacter-free cats were evaluated. Gastric colonization was determined by tissue urease activity, light microscopy, culture and PCR. The mucosal inflammatory response was evaluated by light microscopy, and by RT-PCR of the pro-inflammatory cytokines IL-1alpha, IL-1beta, IL-8 and TNF-alpha in gastric mucosa. Gastric secretory function was assessed by measuring pentagastrin-stimulated acid secretion, fasting plasma gastrin, and antral mucosal gastrin and somatostatin immunoreactivity.

RESULTS

H. pylori colonized the pylorus, fundus and cardia in similar density. Bacteria were observed free in the lumen of gastric glands and were also tightly adherent to epithelial cells where they were associated with microvillus effacement. Mononuclear inflammation, lymphoid follicle hyperplasia, atrophy and fibrosis were observed primarily in H. pylori-infected cats, with the pylorus most severely affected. Neutrophilic and eosinophilic infiltrates, epithelial dysplasia, and up-regulation of mucosal IL-1beta and IL-8 were observed solely in infected cats. Fasting plasma gastrin concentrations and pentagastrin-stimulated acid output were similar in both infected and uninfected cats. There was no relationship of bacterial colonization density or gastric inflammation to plasma gastrin concentrations or gastric acid output.

CONCLUSIONS

The pattern of colonization and the mucosal inflammatory response in cats with naturally acquired H. pylori are broadly similar to those in infected people, particularly children, and non-human primates. The upregulation of IL-8 in infected cats was independent of cagA and picB. Our findings argue against a direct acid-suppressing effect of H. pylori on the gastric secretory-axis in chronically infected cats.

Histological and immunohistochemical detection of different Helicobacter species in the gastric mucosa of cats

Detailed histopathological evaluation of the gastric mucosa of Helicobacter-infected cats is complicated by the difficulty of recognizing Helicobacter organisms on hematoxylin and eosin (HE)-stained sections and the ability of multiple Helicobacter species to infect cats. In this study, the presence and localization of different species of Helicobacter in the stomachs of cats was investigated using silver staining and immunohistochemistry. Five groups containing 5 cats each were established (group 1: urease negative and Helicobacter free; groups 2, 3, 4, and 5: urease positive and infected with Helicobacter heilmannii, unclassified Helicobacter spp., Helicobacter felis, and Helicobacter pylori, respectively). Gastric samples were evaluated by HE and silver staining and by immunohistochemistry with 3 different anti-Helicobacter primary antibodies. Helicobacter were detected by Steiner stain in all infected cats at the mucosal surface, in the lumen of gastric glands, and in the cytoplasm of parietal cells. In silver-stained sections, H. pylori was easily differentiated from H. felis, H. heilmannii, and unclassified Helicobacter spp., which were larger and more tightly coiled. No organisms were seen in uninfected cats. Helicobacter antigen paralleled the distribution of organisms observed in Steiner-stained sections for 2 of the 3 primary antibodies tested. The antisera were not able to discriminate between the different Helicobacter species examined. A small amount of Helicobacter antigen was present in the lamina propria of 3 H. pylori-, 3 H. felis-, and 1 H. heilmannii-infected cat. Minimal mononuclear inflammation was present in uninfected cats and in those infected with unclassified Helicobacter spp. and H. heilmannii cats. In H. felis-infected cats, lymphoid follicular hyperplasia with mild pangastric mononuclear inflammation and eosinophilic infiltrates were present. The H. pylori-infected cats had severe lymphoid follicular hyperplasia and mild to moderate mononuclear inflammation accompanied by the presence of neutrophils and eosinophils. These findings indicate that Steiner staining and immunohistochemistry are useful for detecting Helicobacter infections, particularly when different Helicobacter species can be present. Monoclonal antibodies specific for the different Helicobacter species could be important diagnostic aids. There appear to be differences in the severity of gastritis in cats infected with different Helicobacter species.

Emergence of diverse Helicobacter species in the pathogenesis of gastric and enterohepatic diseases

Since Helicobacter pylori was first cultivated from human gastric biopsy specimens in 1982, it has become apparent that many related species can often be found colonizing the mucosal surfaces of humans and other animals. These other Helicobacter species can be broadly grouped according to whether they colonize the gastric or enterohepatic niche. Gastric Helicobacter species are widely distributed in mammalian hosts and are often nearly universally prevalent. In many cases they cause an inflammatory response resembling that seen with H. pylori in humans. Although usually not pathogenic in their natural host, these organisms serve as models of human disease. Enterohepatic Helicobacter species are an equally diverse group of organisms that have been identified in the intestinal tract and the liver of humans, other mammals, and birds. In many cases they have been linked with inflammation or malignant transformation in immunocompetent hosts and with more severe clinical disease in immunocompromised humans and animals. The purpose of this review is to describe these other Helicobacter species, characterize their role in the pathogenesis of gastrointestinal and enterohepatic disease, and discuss their implications for our understanding of H. pylori infection in humans.