Infection by Strongyloides venezuelensis attenuates chronic colitis induced by Dextran Sodium Sulfate ingestion in BALB/c mice

Inflammatory bowel diseases (IBD) are chronic health problems of difficult management and treatment. Epidemiological studies indicate an inverse association between helminth infections and IBD, and experimental data confirm that helminth infections modulate the severity of experimental acute colitis in mice. However, the effects of helminth infections on chronic colitis, which is clinically more relevant, have been poorly explored. Herein, we investigated whether Strongyloides venezuelensis infection in BALB/c mice can ameliorate chronic colitis induced by the ingestion of water containing 2.5% Dextran Sodium Sulfate (DSS) over three seven-day treatment cycles, with an interval of fourteen days between cycles. Infected-only, DSS-exposed-only, and non-exposed/uninfected experimental groups served as controls for comparing the severity of colitis and intestinal inflammation among different groups. Our data showed that S. venezuelensis infection in mice with DSS-induced chronic colitis reduced clinical signs, attenuated colon shortening and inflammation, and prevented mucus ablation. The modulatory effect was accompanied by a low concentration of IFN-γ, high concentrations of TGF-β, IL-22, and IL-33 in the colon, and a significant increase of the percentage of CD4+CD25+Foxp3+ Treg cells in the mesenteric lymph node (MLN). In conclusion, S. venezuelensis infection can reduce the severity of DSS-induced chronic colitis in mice possibly through the stimulation of Treg cells and modulatory cytokines, and induction of mucosal repair mechanisms.

7-Hydroxy Frullanolide, a sesquiterpene lactone, increases intracellular calcium amounts, lowers CD4+ T cell and macrophage responses, and ameliorates DSS-induced colitis

Sesquiterpene lactones are a class of anti-inflammatory molecules obtained from plants belonging to the Asteraceae family. In this study, the effects of 7-hydroxy frullanolide (7HF), a sesquiterpene lactone, in inhibiting CD4⁺ T cell and peritoneal macrophage responses were investigated. 7HF, in a dose dependent manner, lowers CD69 upregulation, IL2 production and CD4⁺ T cell cycling upon activation with the combination of anti-CD3 and anti-CD28. Further mechanistic studies demonstrated that 7HF, at early time points, increases intracellular Ca²⁺ amounts, over and above the levels induced upon activation. The functional relevance of 7HF-induced Ca²⁺ increase was confirmed using sub-optimal amounts of BAPTA, an intracellular Ca²⁺ chelator, which lowers lactate and rescues CD4⁺ T cell cycling. In addition, 7HF lowers T cell cycling with the combination of PMA and Ionomycin. However, 7HF increases CD4⁺ T cell cycling with sub-optimal activating signals: only PMA or anti-CD3. Furthermore, LPS-induced nitrite and IL6 production by peritoneal macrophages is inhibited by 7HF in a Ca²⁺-dependent manner. Studies with Ca²⁺ channel inhibitors, Ruthenium Red and 2-Aminoethoxydiphenyl borate, lowers the inhibitory effects of 7HF on CD4⁺ T cell and macrophage responses. In silico studies demonstrated that 7HF binds to Ca²⁺ channels, TRPV1, IP3R and SERCA, which is mechanistically important. Finally, intraperitoneal administration of 7HF lowers serum inflammatory cytokines, IFNγ and IL6, and reduces the effects of DSS-induced colitis with respect to colon length and colon damage. Overall, this study sheds mechanistic light on the anti-inflammatory potential of 7HF, a natural plant compound, in lowering immune responses.

Eosinophilic esophagitis, gastroenteritis, and colitis in a patient with prior parasite exposure

Eosinophilic gastrointestinal disorders (EGID) comprise a spectrum of inflammatory diseases that can affect any segment of the gastrointestinal tract. The pathogenesis of these conditions is complex; differentiating between primary and secondary forms of these disorders can be clinically challenging. We report a case of primary EGID in a patient with remote parasite exposure, whose symptoms were initially attributed to irritable bowel syndrome. Endoscopy revealed the rare finding of EGID involving the entire gastrointestinal tract; symptoms improved with an elimination diet. This case raises the possibility of a link between prior parasite exposure and development of EGID, and underscores the necessity of exploring alternative diagnoses in patients with presumed IBS who present with severe symptoms.

Acute infection with Strongyloides venezuelensis increases intestine production IL-10, reduces Th1/Th2/Th17 induction in colon and attenuates Dextran Sulfate Sodium-induced colitis in BALB/c mice

Helminth infection can reduce the severity of inflammatory bowel disease. However, the modulatory mechanisms elicited by helminth infection are not yet fully understood and vary depending on the experimental model. Herein we evaluated the effect of acute infection of BALB/c mice with Strongyloides venezuelensis on the clinical course of ulcerative colitis induced by Dextran Sulfate Sodium (DSS) treatment of these animals. For the experiments, S. venezuelensis-infected BALB/c mice were treated orally with 4% DSS solution for seven days. As controls, we used untreated S. venezuelensis infected, DSS-treated uninfected, and untreated/uninfected BALB/c mice. During DSS treatment, mice from the different groups were compared with regards to the clinical signs related to the severity of colitis and intestinal inflammation. Mice acutely infected with S. venezulensis and treated with DSS had reduced clinical score, shortening of the colon, and tissue inflammation. Moreover, DSS-treated and infected mice showed reduced IL-4, INF-γ, and IL-17 levels and increase of IL-10 production in the colon and/or in the supernatant of mesenteric lymph nodes cell cultures that resulted in lower eosinophil peroxidase and myeloperoxidase activity in colon homogenates, when compared with DSS-treated uninfected mice. DSS-treated infected mice also preserved the intestine architecture and had normal differentiation of goblet cells and mucus production in the colon mucosa. In conclusion, the data indicate that the clinical improvement reported in DSS-treated infected mice was accompanied by the lower production of Th1/Th2/Th17 pro-inflammatory cytokines, stimulation of IL-10, and induction of mucosal repair mechanisms.

Histologic Features Associated with Tritrichomonas foetus-induced Colitis in Domestic Cats

Tritrichomonas foetus is a venereal pathogen of naturally bred cattle. In domestic cats, T. foetus colonizes the colon, resulting in chronic, large-bowel diarrhea. The infection is prevalent among young, densely housed cats, and there is no effective treatment. To the authors' knowledge, the characteristic microscopic lesions of T. foetus infection in naturally infected cats have not been described. The aim of the study reported here was to characterize the histologic changes in the colon of seven cats with T. foetus infection and chronic diarrhea. All cats were 1 year old or younger (mean, 6.7 ± 1.7 months), and a diagnosis of T. foetus infection was made on the basis of direct fecal smear examination (five cats), fecal culture in InPouch™ TF medium (four cats), single-tube nested polymerase chain reaction (PCR) analysis of DNA extracted from feces (two cats), or observation of trichomonads in sections of colon followed by PCR confirmation on DNA extracted from paraffin-embedded tissue (two cats). The presence of colonic trichomonads was the most diagnostic histologic feature. Organisms were identified in all cats, but in only 24 of 43 (56%) sections of colon. Trichomonads were generally present in close proximity to the mucosal surface and less frequently in the lumen of colonic crypts. The presence of colonic trichomonads was consistently associated with mild-to-moderate lymphoplasmacytic and neutrophilic colitis, crypt epithelial cell hypertrophy, hyperplasia and increased mitotic activity, loss of goblet cells, crypt microabscesses, and attenuation of the superficial colonic mucosa. In two of the cats, histologic lesions were more severe and were associated with invasion of trichomonads into the lamina propria and/or deeper layers of the colon.

Gastritis, Enteritis, and Colitis in Horses

The gastrointestinal system of horses is affected by a large variety of inflammatory infectious and noninfectious conditions. The most prevalent form of gastritis is associated with ulceration of the pars esophagea. Although the diagnostic techniques for alimentary diseases of horses have improved significantly over the past few years, difficulties still exist in establishing the causes of a significant number of enteric diseases in this species. This problem is compounded by several agents of enteric disease also being found in the intestine of clinically normal horses, which questions the validity of the mere detection of these agents in the intestine.

The pathogenic role of Blastocystis isolated from patients with irritable bowel syndrome and colitis from Iasi, Romania

Blastocystis is a common parasite and regarded as one of the etiologic agents of irritable bowel syndrome, colitis and chronic diarrhea. Our study was undertaken in order to identify different subtypes of Blastocystis isolated in patients with irritable bowel syndrome and colitis, as well as with chronic diarrhea and to evaluate their pathogenic potential. Seventy-three subjects (10 asymptomatic infected subjects, 49 subjects harboring Blastocystis or associated with other etiologic agents like bacteria, yeasts, protozoa, helminthes and 14 subjects with unknown etiologic agents) were investigated by in vitro parasitological and bacteriological stool samples followed by PCR subtyping of Blastocystis using STS primers, immunological markers (total serum IgA and IgE antibody levels), Helicobacter pylori antigen rapid test and fecal occult blood test. Also, among 49 subjects, there were 12 subjects harboring Blastocystis as the single etiologic agent. Subtyping proved that only three subtypes of Blastocystis were identified as following: subtype II (66.66%) in single infected subjects, subtype I (16.66%) in mixed infection with subtype II and subtype IV (8.33%) in single infected subjects. Total serum IgA and IgE antibody levels were in normal range. Subtype II was the most frequent subtype followed by subtype I and subtype IV of Blastocystis isolates in patients with irritable bowel syndrome, colitis, and chronic diarrhea as well as in asymptomatic infected group. Our results suggest that the severity of clinical manifestations depend on factors involving the host and possible parasitic density and not necessarily by isolated subtype.

Increased susceptibility to Trichuris muris infection and exacerbation of colitis in Mdr1a-/- mice

AIM: To investigate the influence of Trichuris muris (T. muris) infection in a mouse model of genetic susceptibility to inflammatory bowel disease, Mdr1a-/-.

METHODS: Mdr1a-/- mice were housed under specific pathogen free conditions to slow the development of colitis and compared to congenic FVB controls. Mice were infected with approximately 200 embryonated ova from T. muris and assessed for worm burden and histological and functional markers of gut inflammation on day 19 post infection.

RESULTS: Mdr1a-/- mice exhibited a marked increase in susceptibility to T. muris infection with a 10-fold increase in colonic worm count by day 19 pi compared to FVB controls. Prior to infection, Mdr1a-/- exhibited low-level mucosal inflammation with evidence of an enhanced Th1 environment. T. muris infection accelerated the progression of colitis in Mdr1a-/- as evidenced by marked increases in several indicators including histological damage score, mucosal CD4⁺ T-cell and DC infiltration and dramatically increased production of pro-inflammatory cytokines.

CONCLUSION: These data provide further evidence of the complex interaction between T. muris and an inflammatory bowel disease (IBD)-susceptible host which may have relevance to the application of helminth therapy in the treatment of human IBD.

Myenteric plexus is differentially affected by infection with distinct Trypanosoma cruzi strains in Beagle dogs

Chagasic megaoesophagus and megacolon are characterised by motor abnormalities related to enteric nervous system lesions and their development seems to be related to geographic distribution of distinct Trypanosoma cruzi subpopulations. Beagle dogs were infected with Y or Berenice-78 (Be-78) T. cruzi strains and necropsied during the acute or chronic phase of experimental disease for post mortem histopathological evaluation of the oesophagus and colon. Both strains infected the oesophagus and colon and caused an inflammatory response during the acute phase. In the chronic phase, inflammatory process was observed exclusively in the Be-78 infected animals, possibly due to a parasitism persistent only in this group. Myenteric denervation occurred during the acute phase of infection for both strains, but persisted chronically only in Be-78 infected animals. Glial cell involvement occurred earlier in animals infected with the Y strain, while animals infected with the Be-78 strain showed reduced glial fibrillary acidic protein immunoreactive area of enteric glial cells in the chronic phase. These results suggest that although both strains cause lesions in the digestive tract, the Y strain is associated with early control of the lesion, while the Be-78 strain results in progressive gut lesions in this model.

Schistosomiasis combined with colorectal carcinoma diagnosed based on endoscopic findings and clinicopathological characteristics: a report on 32 cases

AIMS AND BACKGROUND

To improve understanding of the relationship between schistosome-related enteropathy and colorectal carcinoma with particular focus on endoscopic findings and clinicopathological characteristics of colonic schistosomiasis.

MATERIALS AND METHODS

All cases of intestinal schistosomiasis diagnosed at West China Hospital, Chengdu, China, between October 2006 and October 2012 were included in this study. A total of 179 cases of colonic schistosomiasis diagnosed through colonoscopy and pathological examinations were collected for analysis and the demographics, symptoms, endoscopic findings and clinicopathological characteristics were retrospectively evaluated.

RESULTS

Of the 179 colonic schistosomiasis patients, 32 combined with colorectal cancer (CRC) were found, between the ages of 44 and 85 years (24 males, 75%). These 32 lesions were classified as 12 endophytic/ulcerative (37.5%), 10 exophytic/fungating (31.2%), 4 annular (12.5%), 3 giant polypus (9.4%), and 3 IIc (superficial depressed type) (9.4%). The segments of rectum and sigmoid colon were involved in 19 patients (59.4%) and 6 patients (18.8%), respectively. The histopathologic types were classified as follows: 30 well- differentiated adenocarcinomas, one mucinous adenocarcinoma and one poorly differentiated adenocarcinoma. The pathological findings suggest colorectal malignancy with deposited schistosome ova.

CONCLUSIONS

Chronic schistosomal infestation has a probable etiological role in promoting genesis of colorectal neoplasms.

Acute fulminant necrotizing amoebic colitis: a potentially fatal cause of diarrhoea on the Acute Medical Unit

Diarrhoea is a common presenting complaint to the Acute Medical Unit. We report a case of acute fulminant necrotizing amebic colitis in a 73 year old man with no recent travel history preceding his admission. Such cases are often difficult to diagnose and hence associated with a high mortality, unless treated promptly and appropriately. This case report highlights the importance of early diagnosis and prompt initiation of treatment.

Chronic diarrhea and abdominal pain: pin the pinworm

Enterobius vermicularis is the most common helminthic infection in the US. It is usually considered an innocuous parasite that at the most causes perianal itching. We report a case of an 84-year-old female patient from an assisted living facility who presented with symptoms of colitis for 2 months. On detailed history and exam, she was found to have E. vermicularis infection. All her symptoms resolved dramatically within 2 days after a single dose of albendazole. We want to emphasize the importance of including parasitic infections such as E. vermicularis in the differential diagnoses of patients presenting with symptoms of colitis.

Ultrastructure and some pathological pictures of Gastrodicus aegyptiacus (Cobbold, 1876) in Egyptian horses

The surface ultrastructure (SEM) of adult worms and eggs of the equine caecal fluke, Gastodiscus aegyptiacus, together with some pathological observations of the caecum and colon of infected horses were studied. SEM showed that G. aegyptiacus had a disc-like body with anterior cone-like part. The oral sucker was surrounded by numerous dome-shaped papillae. The cone-like part possessed tubercle-like papillae at its anterior third. The large ventral sucker was subterminal with small papillae at its rim. The ventral surface was covered with large cauliflower-like papillae. Microvilli were densely arranged on the egg shell surface. The pathological changes were proved by severe haemorrhagic colitis.

Group G streptococcal bacteremia and vertebral osteomyelitis in a homosexual man with amebic colitis

We present a case of bacteremia caused by group G streptococci (GGS) and vertebral osteomyelitis in a homosexual man with amebic colitis. The organism likely entered the blood via the inflamed intestinal mucosa resulting from amebiasis. Arthritis of both hands, which probably represented poststreptococcal reactive arthritis, was also observed. We should be aware that diseases caused by GGS appear to be increasing in recent years, and a potential for serious infection exists with regard to GGS as well as group A streptococci.

Enteritis and colitis in horses

Enteritis and colitis remain challenging and life-threatening diseases despite many recent advances. Successful treatment is largely dependent on early recognition and directed therapy, which is facilitated by obtaining a complete history and physical examination. A number of new therapies and methods of monitoring critically ill patients have become integral components of treatment success. The critical monitoring of equine foals and adults continues to be an exciting and emerging field.

Time course of neural and contractile disturbances in a rat model of colitis induced by Trichinella spiralis

Colitis induced by Trichinella spiralis in rat induces alterations in the spontaneous motor pattern displayed by circular colonic muscle [Auli, M., Fernandez, E., 2005. Characterization of functional and morphological changes in a rat model of colitis induced by T. spiralis. Digestive Diseases and Sciences 50(8), 1432-1443]. We examined the temporal relationship between the severity of inflammation and the altered contractility of the underlying circular muscle as well as the role of NANC inhibitory pathways in the disruption of the motility pattern. Colitis was induced by intrarectal administration of T. spiralis larvae. Responses to acetylcholine (ACh) and increased extracellular potassium as well as the effect of tetrodotoxin (TTX, 1 microM), N-nitro-l-arginine (L-NOARG, 1 mM) and apamin (1 microM) were determined in vitro in the organ bath with circular muscle strips from sham-infected and infected rats at days 2-30 postinfection (PI). Microelectrode recordings were performed to study the putative changes in electrical activity of colonic smooth muscle cells. Responses to ACh and KCl were decreased at all days PI compared to sham. Intracellular calcium depletion had a greater inhibitory effect in inflamed tissue (6-14 PI). The effect of TTX, L-NOARG and apamin on the spontaneous contractions was found to be altered in all infected rats, i.e. their effects were transient and milder. Inflamed tissue showed lower resting membrane potential and a decreased duration of inhibitory junction potentials induced by electrical stimulation. These data suggest that the decreased contractility of colonic circular smooth muscle induced by the intrarectal T. spiralis infection results from the impairment of the excitation-contraction coupling, from a persistent hyperpolarization of smooth muscle cells and from impaired NANC inhibitory neurotransmission.

Colorectal cancer in a population with endemic Schistosoma mansoni: is this an at-risk population?

PURPOSE

Chronic infection with schistosomiasis has been clearly associated with the development of bladder cancer, and infestation is associated with a high incidence of colorectal cancer in endemic populations. Despite this association, the potential role of alterations in tumor suppressor genes colorectal cancers has never been evaluated in an endemically infected population. The aim of this paper was to compare histopathologic and genetic changes in schistosomal colitis-associated colorectal cancer (SCC) with colorectal cancer in a group of patients from the same population not affected by the disease (NDCC).

MATERIALS AND METHODS

Sixty patients were included in this study: SCC-40, NDCC-20. Data collected included age, sex, clinical presentation, presence of synchronous tumors, histopathology, and clinical stage. p53, DCC (deleted in colorectal cancer gene), and mismatch repair genes (MLH1 and MSH2) were studied using immunohistochemical staining.

RESULTS

Patients with SCC were significantly younger than the NDCC group (34.52+/-11.22 years vs 50.73+/-12.75 years, p=0.02). Mucinous adenocarcinoma occurred significantly more frequently in SCC (35 vs 10%, p=0.02). SCC tumors were more frequently stage III or IV, and significantly more synchronous tumors were present in the affected group (SCC-8/40 vs NDCC-1/20, p=0.05). p53 staining was far more frequent in SCC (SCC-32/40 vs NDCC-8/20, p=0.006). DCC expression was similar in two groups. There were only four cases, three in SCC and one in NDCC, that showed microsatellite instability.

CONCLUSION

The data suggest that schistosomal colitis is more commonly associated with earlier onset of multicentric colorectal cancer, high percentage of mucinous adenocarcinoma, and presents at an advanced stage. The identification of a higher incidence of altered p53 expression in the SCC group raises the possibility of an association between schistosomiasis and alterations in p53 activation as an inciting event in colorectal cancer development.

Asymptomatic colitis in naturally infected dogs with Leishmania infantum: a prospective study

A total of 31 dogs with naturally occurring and symptomatic leishmaniasis (Leishmania infantum), but without historical or clinical evidence of overt colitis, were included in this study. With owners' consent, a colonoscopy was performed in all these dogs, revealing patches of hyperemic, edematous, irregular, and mildly erosive colonic mucosa in 25.8% of the animals. Biopsies were obtained from the colonic mucosa and stained with hematoxylin-eosin (histopathology) and avidin-biotin-peroxidase technique (immunohistochemical detection of parasites). Leishmania amastigotes were detected immunohistochemically in 32.3% of the dogs. The most common inflammatory pattern in the colonic mucosa of these dogs was pyogranulomatous (90%), whereas in the dogs without Leishmania amastigotes immunohistochemically detected in the colonic mucosa (67.7%), there was no evidence of gross and microscopic lesions. Also, in 2 of the 10 dogs in which parasites were detected immunohistochemically in the colonic mucosa, no lesions could be detected on colonoscopy. There was no correlation between the dogs with or without parasites detected in the colonic mucosa regarding the sex, age, or the type of diet of these animals. However, the positive correlation (P < 0.001) found between colonic parasitism and gross lesions detected on colonoscopy would justify the inclusion of canine leishmaniasis in the list of differentials of canine chronic or recurrent colitis.

Colitis due to Ancylostoma duodenale

The larva of hookworm matures into the adult stage in the small intestine, causing chronic intestinal blood loss and iron-deficiency anemia. Hookworm infestation of colon has not been reported previously. We report a 35-year-old man who presented with diarrhea with blood and mucus in stools. Colonoscopy revealed several hookworms in the colon firmly adherent to the mucosa, with oozing of blood and surrounding mucosal erosions. He was treated with mebendazole and symptoms recovered completely.

Enterobius vermicularis and colitis in Children

OBJECTIVES

We observed a cohort of children presenting with rectal bleeding that were identified as having Enterobius vermicularis at colonoscopy and questioned the reliability of conventional diagnostic methods of identifying E. vermicularis.

PATIENTS AND METHODS

The study was retrospective in nature and subjects were investigated by colonoscopy between May 1997 and December 1999. Patients were identified as having E. vermicularis infestation by direct visualisation of the adult worms at colonoscopy. Patients were treated with mebendazole and a record of their clinical response documented.

RESULTS

A total of 180 colonoscopic examinations were performed during the study period. E. vermicularis was identified macroscopically in 31 cases (17.2%). The symptom profile of patients with E. vermicularis were abdominal pain, 19 of 26 (73%); rectal bleeding, 16 of 26 (62%); chronic diarrhoea, 13 of 26 (50%) and weight loss, 11 of 26 (42%). Ova cysts and parasites were identified in none of the saline swabs analysed in 20 patients. Sellotape testing was performed in only 4 patients and was negative in all. Of the 26 children, 21 (81%) demonstrated histopathological features of nonspecific colitis. There was clinical resolution of symptoms in 19 of 23 patients.

CONCLUSIONS

We suggest that in patients with symptoms suggestive of inflammatory bowel disease, E. vermicularis infestation must be excluded as a common cause of nonspecific colitis. We also suggest that diagnostic tests such as saline swabs and Sellotape testing may be lacking in sensitivity.

Induction of CD8+ regulatory T cells in the intestine by Heligmosomoides polygyrus infection

This study determined whether Heligmosomoides polygyrus induces intestinal regulatory T cells. Splenic T cells proliferate strongly when cultured with anti-CD3 and antigen-presenting cells (APC). Lamina propria T cells from mice with H. polygyrus mixed with normal splenic T cells from uninfected mice inhibited proliferation over 90%. Lamina propria T cells from mice without H. polygyrus only modestly affected T cell proliferation. The worm-induced regulatory T cell was CD8+ and required splenic T cell contact to inhibit proliferation. The regulation also was IL-10 independent, but TAP-dependent, suggesting that it requires major histocompatibility complex (MHC) class I interaction. Additional studies employed mice with transgenic T cells that did not express functional TGF-beta receptors. The lamina propria T regulator inhibited proliferation of these transgenic T cells nearly 100%, suggesting that TGF-beta signaling via the T cell was not required. CD8+ T cells were needed for worms to reverse piroxicam-induced colitis in Rag mice (T and B cell deficient) reconstituted with IL-10-/- T cells. Thus H. polygyrus induces a regulatory CD8+ lamina propria T cell that inhibits T cell proliferation and that appears to have a role in control of colitis.

Crohn's colitis perforation due to superimposed invasive amebic colitis: a case report

The clinical and microscopic appearances of inflammatory bowel disease may be very similar to those of amebic colitis. The coexistence of invasive amebiasis with inflammatory bowel disease may have disastrous results. Patients with inflammatory bowel disease have a greater prevalence of amebiasis, but this association is more significant for ulcerative colitis. There have been very few reports in the literature presenting the superimposition of amebiasis on Crohn's disease. In this report, a rare case of Crohn's colitis with superimposed amebiasis resulting in colonic perforation is presented. Patients with inflammatory bowel disease traveling to endemic areas may benefit from receiving a course of prophylactic anti-amebic medication.

Iatrogenic Trichuris suis infection in a patient with Crohn disease

We report a case of biopsy-proven iatrogenic infection by the pig whipworm Trichuris suis in a patient with Crohn disease. The deliberate therapeutic ingestion of T suis ova has been adopted as an experimental approach to the treatment of Crohn disease in an effort to promote a switch from the T helper subtype 1 to T helper subtype 2 inflammatory phenotype in vivo. This report examines the morphology of the immature and adult T suis, the effects of this intervention on the immunophenotype of the bowel mucosa, and it also raises the possibility of persistent active infection in man.

Concurrent infection with an intestinal helminth parasite impairs host resistance to enteric Citrobacter rodentium and enhances Citrobacter-induced colitis in mice

Infections with intestinal helminth and bacterial pathogens, such as enteropathogenic Escherichia coli, continue to be a major global health threat for children. To test the hypothesis that intestinal helminth infection may be a risk factor for enteric bacterial infection, a murine model was established by using the intestinal helminth Heligomosomoides polygyrus. To analyze the modulatory effect of a Th2-inducing helminth on the outcome of enteric bacterium Citrobacter rodentium infection, BALB/c and STAT 6 knockout (KO) mice were infected with H. polygyrus, C. rodentium, or both. We found that only BALB/c mice coinfected with H. polygyrus and C. rodentium displayed a marked morbidity and mortality. The enhanced susceptibility to C. rodentium and intestinal injury of coinfected BALB/c mice were shown to be associated with a significant increase in helminth-driven Th2 responses, mucosally and systemically, and correlated with a significant downregulation of protective gamma interferon and with a dramatic upregulation of the proinflammatory tumor necrosis factor alpha response. In addition, C. rodentium-associated colonic pathology in coinfected BALB/c mice was significantly enhanced, whereas bacterial burden was increased and clearance was delayed. In contrast, coinfection in STAT 6 KO mice failed to promote C. rodentium infection or to induce a more severe intestinal inflammation and tissue injury, demonstrating a mechanism by which helminth influences the development of host protective immunity and susceptibility to bacterial infections. We conclude that H. polygyrus coinfection can promote C. rodentium-associated disease and colitis through a STAT 6-mediated immune mechanism.

Neutralizing anti-IL-10 antibody blocks the protective effect of tapeworm infection in a murine model of chemically induced colitis

There is increasing evidence that parasitic helminth infection has the ability to ameliorate other disease conditions. In this study the ability of the rat tapeworm, Hymenolepis diminuta, to modulate dinitrobenzene sulfonic acid (DNBS)-induced colitis in mice is assessed. Mice receiving DNBS (3 mg intrarectally) developed colitis by 72 h after treatment. Mice infected 8 days before DNBS with five H. diminuta larvae were significantly protected from the colitis, as gauged by reduced clinical disease, histological damage scores, and myeloperoxidase levels. This anticolitic effect was dependent on a viable infection and helminth rejection, because no benefit was observed in mice given killed larvae or in infected STAT6 knockout mice or rats, neither of which eliminate H. diminuta. The anticolitic effect of H. diminuta was associated with increased colonic IL-10 mRNA and stimulated splenocytes from H. diminuta- plus DNBS-treated mice produced more IL-10 than splenocytes from DNBS-only treated mice. Coadministration of an anti-IL-10 Ab blocked the anticolitic effect of prophylactic H. diminuta infection. Also, mice infected 48 h after DNBS treatment showed an enhanced recovery response. Finally, using a model of OVA hypersensitivity, we found no evidence of concomitant H. diminuta infection enhancing enteric responsiveness to subsequent ex vivo OVA challenge. The data show that a viable infection of H. diminuta in a nonpermissive system exerts a profound anticolitic effect (both prophylactically and as a treatment) that is mediated at least in part via IL-10 and does not predispose to enhanced sensitivity to bystander proteins.

HIV infection associated with Strongyloides stercoralis colitis resulting in Streptococcus bovis bacteraemia and meningitis

We report the case of an HIV infected patient with Streptococcus bovis bacteraemia and meningitis associated with gastrointestinal Strongyloides stercoralis infection. To our knowledge, this has been reported once previously and serves as a reminder to actively exclude asymptomatic S stercoralis infection in HIV infected individuals presenting with bacteraemia.

Effects of Changtai granules, a traditional compound Chinese medicine, on chronic trinitrobenzene sulfonic acid-induced colitis in rats

AIM: To study the effects of Changtai granules (CTG), a traditional compound Chinese medicine, on chronic trinitrobenzene sulfonic acid-induced colitis in rats.

METHODS: Healthy adult Sprague-Dawley (SD) rats of both sexes, weighing 250-300 g, were employed in the present study. The rat colitis models were induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) enemas at a concentration of 100 mg/kg in 50% ethanol. The experimental animals were randomly divided into dexamethasone (DX) treatment, CTG treatment, and model control groups, which were intracolicly treated daily with DX (0.2 mg/kg), CTG at doses of 2.9, 5.7 and 11.4 g crude drug/kg, and the equal amount of saline respectively from 6 h following induction of the colitis in rats inflicted with TNBS to the end of study. A normal control group of rats treated without TNBS but saline enema was also included in the study. After 3 wk of treatment, the animals were assessed for colonal inflammatory and ulcerative responses with respect to mortality, frequency of diarrhea, histology and myeloperoxidase activity (MPO).

RESULTS: The therapeutic effect of CTG on ulcerative colitis (UC) was better than DX. CTG effectively inhibited the activity of granulocytes, macrophages and monocytes in a dose-dependent manner. Also it reduced MPO and formation of inflammation in colonic mucosal tissue. Furthermore, administration of CTG significantly prevented body mass loss and death, and decreased frequency of diarrhea in UC rats, when compared with the model control group rats.

CONCLUSION: CTG would prove to be an ideal drug for chronic UC, and is warranted to be studied further.

[Colonic involvement in chronic opisthorchiasis]

OBJECTIVE

To provide clinical, functional, and morphological characteristics of colonic involvement in chronic opisthorchiasis and to evaluate the efficiency of dehelmintization.

SUBJECTS AND METHODS

96 patients with chronic non-ulcerative colitis, including 56 patients who had chronic opisthorchiasis (Group 1) and 40 patients who had no parasitic diseases (Group 2). The biocenosis of the large bowel, the motor function and morphological status of its distal and proximal parts were evaluated in all the patients. Biopsy specimens were histologically studied.

RESULTS AND DISCUSSION

There was an association of impaired colonic motor activity and morphological colonic mucosal changes with the intensity and duration of Opisthorchis invasion. A marked eosinophilic infiltration of the colonic mucosa was noted in all morphological types of chronic non-ulcerative colitis in patients with chronic opisthorchiasis. Effective dehelmintization caused positive functional and morphological changes in the large bowel. All the above facts support the likelihood of parasitic colitis in chronic opisthorchiasis and the expediency of dehelmintization.

Katayama syndrome

Two schoolboys from a non-endemic region visited an endemic area of Schistosomiasis in Yemen. They developed cutaneous itching after swimming in infected ponds. Five weeks later both brothers were admitted to the hospital with high fever, abdominal pain, vomiting and diarrhea. The blood results exhibited marked eosinophilia and schistosomal serological test showed an evidence of exposure. Initially, stool examinations were negative, but the sigmoidoscopy was suggestive for acute bilharzial colitis and the biopsy showed schistosoma ova; a finding consistent with Katayama syndrome. Both patients treated with Praziquantel, and they became asymptomatic, and the eosinophilia normalized. This report shows the importance of endoscopic and histological examination in suspected acute colonic schistosomiasis, which allows early treatment and avoids possible complications.

[Severe diarrhea and eosinophilic colitis attributed to pinworms (Enterobius vermicularis)]

In a 32-year-old woman suffering from severe diarrhoea, eosinophilic infiltration of colonic mucosa and a peripheral eosinophilia, microbiological investigations only revealed large numbers of Enterobius vermicularis (pinworm) in the faeces. Treatment with mebendazole resulted in a rapid resolution of symptoms and disappearance of the eosinophilia, which strongly suggested a causative role of this pinworm in the clinical syndrome of the patient. E. vermicularis is generally regarded as an innocent nematode, which at most causes perianal pruritus due to migration of worms from the colon and expulsion of eggs onto the perianal skin. Although the pinworm maturates and lives in the gut, gastrointestinal symptoms have seldom been reported. E. vermicularis infection should be considered in patients with unexplained eosinophilic enteritis.

[Analysis of the results of 1221 colonoscopies in the hospitals of Burkina Faso, 1994-1997]

The authors report the results of 1221 colonoscopies. It appears from their analysis that whereas functional diseases of the colon remain predominant and topical, organic diseases appear to be increasing in frequency (polyps, polyposis, rectocolic cancer, parasitical colitis, diverticulis). Inflammatory bowel diseases are also beginning to be seen. The reported cases of Crohn's disease and ulcerative colitis are, so far as they know, the first in their country.

Microbes and microbial toxins: paradigms for microbial-mucosal interactions. VI. Entamoeba histolytica: parasite-host interactions

The protozoan intestinal parasite Entamoeba histolytica remains a significant cause of morbidity and mortality worldwide. E. histolytica causes two major clinical syndromes, amebic colitis and amebic liver abscess. Recent advances in the development of in vitro and in vivo models of disease, new genetic approaches, the identification of key E. histolytica virulence factors, and the recognition of crucial elements of the host response to infection have led to significant insights into the pathogenesis of amebic infection. E. histolytica virulence factors include 1) a surface galactose binding lectin that mediates E. histolytica binding to host cells and may contribute to amebic resistance to complement, 2) amebapores, small peptides capable of lysing cells, which may play a role in killing intestinal epithelial cells, hepatocytes, and host defense cells, and 3) a family of secreted cysteine proteinases that play a key role in E. histolytica tissue invasion, evasion of host defenses, and parasite induction of gut inflammation. Amebae can both lyse host cells and induce their suicide through programmed cell death. The host response is also an important factor in the outcome of infection, and neutrophils may play a key role in contributing to the tissue damage seen in amebiasis and in controlling amebic infection.

Caspase 3-dependent killing of host cells by the parasite Entamoeba histolytica

The parasite Entamoeba histolytica is named for its ability to lyse host tissues. To determine the factors responsible, we have initiated an examination of the contribution of parasite virulence factors and host caspases to cellular destruction by the parasite. Amoebic colitis in C3H/HeJ mice was associated with extensive host apoptosis at sites of E. histolytica invasion. In vitro studies of E. histolytica-Jurkat T-cell interactions demonstrated that apoptosis required contact via the amoebic Gal/GalNAc lectin, but was unaffected by 75% inhibition of the amoebic cysteine proteinases. Parasite-induced DNA fragmentation was unaffected in caspase 8-deficient Jurkat cells treated with the caspase 9 inhibitor Ac-LEHD-fmk. In contrast, caspase 3-like activity was observed within minutes of E. histolytica contact and the caspase 3 inhibitor Ac-DEVD-CHO blocked Jurkat T cell death, as measured by both DNA fragmentation and 51Cr release. These data demonstrate rapid parasite-induced activation of caspase 3-like caspases, independent of the upstream caspases 8 and 9, which is required for host cell death.

[Amebiasis]

Amoebiasis caused by the enteric protozoan Entamoeba histolytica is a widespread parasitic disease, which causes 40,000 to 100,000 deaths per year. Cases diagnosed in Denmark are always imported. Infection results from ingestion of amoebic cysts, which after excystation form trophozoits in the small intestine, colonize the bowel lumen and invade the intestinal epithelium resulting in amoebic colitis. Spread to the liver and formation of amoebic liver abscesses occurs in one third of the cases, whereas other extraintestinal manifestations are rare. Amoebic colitis and liver abscess have a good prognosis when treated with metronidazole, whereas complications such as necrotizing colitis, peritonitis and pericarditis have a high mortality. An early diagnosis and treatment is therefore important. Intestinal amoebiasis is diagnosed by demonstration of E. histolytica cysts or amoebae in the stools, whereas serology is of value in diagnosing extraintestinal amoebiasis in nonendemic regions.

Strongyloidiasis colitis: a case report and review of the literature

A case is described of a nonimmunocompromised man who presented with diarrhea, weight loss, and microcytic anemia. Colonoscopy revealed a pancolitis characterized by aphthoid ulceration on endoscopy and intense tissue eosinophilic infiltrates on biopsy. Both colonic biopsies and stool aspirates revealed the larvae of Strongyloides stercoralis, thus confirming this parasite as the causative agent for the colitis.

Profile of lower gastrointestinal bleeding in children from a tropical country

Eighty five children were evaluated endoscopically for recurrent lower gastrointestinal (GI) bleeding. The male: female ratio was 2.4:1 with a mean age of 6 years (range 8 months to 2 years). After adequate bowel preparation endoscopic evaluation was done using olympus CF 101 colonoscope. Sedation was given only in two patients. Full length colonoscopy had been done in 16 cases only, to look for extent of disease in 8 cases and to ascertain site of bleeding when no lesion could be seen on sigmoidoscopy. Juvenile polyps were seen in 40 cases, amoebic ulcer in 20, solitary rectal ulcer in 4 and polyposis syndrome in 5 cases. Sigmoidoscopy alone could establish the diagnose in 76 cases. We conclude that flexible sigmoidoscopy alone is safe and adequate in ascertaining the cause of prolonged recurrent lower GI bleeding.

Investigations into field cases of porcine colitis with particular reference to infection with Serpulina pilosicoli

Investigations into the possible causes of colitis and typhlocolitis were carried out on 85 pig units in the United Kingdom between 1992 and 1996. Serpulina pilosicoli was identified most commonly, occurring as the suggested primary agent on 21 (25 per cent) of the units but forming part of mixed infections on another 23 (27 per cent) of the units, the main co-infections being Yersinia pseudotuberculosis (eight units), proliferative enteropathy (six units), Salmonella species (four units) or Serpulina hyodysenteriae (two units). 'Atypical' Serpulina species, S hyodysenteriae, Salmonella typhimurium, Y pseudotuberculosis and Lawsonia intracellularis (proliferative enteropathy) were the suggested primary agents on seven, six, four, four and three units, respectively. Various combinations of mixed infections involving the latter organisms and other possibly incidental agents were recorded on another 10 units. Investigations on a further six units failed to detect any recognised pathogens. On units where S pilosicoli was the suggested primary agent, pigs ranging between 20 to 40 kg (eight to 16 weeks of age), but occasionally up to 50 kg, had diarrhoea and grew poorly over a period of two to three weeks. The prevalence was estimated to be between 5 and 15 per cent in affected batches, with a mortality of approximately 1 per cent. The clinical signs usually developed seven to 14 days after the moving and mixing of pigs. At postmortem examination, affected pigs had liquid contents in their colon, which contained accumulations of mucus in some chronic cases. Gross and histological lesions of colitis were prominent in the mid-spiral region of the colon. In mixed infections with Y pseudotuberculosis, Salmonella typhimurium or S hyodysenteriae, lesions were more extensive and affected the caecum as well as the colon. In the colon, lesions of proliferative enteropathy were usually confined to the proximal half of the ascending spiral but mixed infection with S pilosicoli caused more extensive colitis. Mixed infections were reported to prolong the time taken for pigs to recover naturally and to have a more detrimental effect on growth rates than S pilosicoli infection alone. Despite the successful treatment of batches of pigs with tiamulin or lincomycin, S pilosicoli infection persisted as a chronic problem on many units, with diarrhoea and colitis in successive batches of pigs unless prophylactic medication was used.