Treatment with the Probiotic Product Aviguard® Alleviates Inflammatory Responses during Campylobacter jejuni-Induced Acute Enterocolitis in Mice.

Prevalences of Campylobacter (C.) jejuni infections are progressively rising globally. Given that probiotic feed additives, such as the commercial product Aviguard®, have been shown to be effective in reducing enteropathogens, such as Salmonella, in vertebrates, including livestock, we assessed potential anti-pathogenic and immune-modulatory properties of Aviguard® during acute C. jejuni-induced murine enterocolitis. Therefore, microbiota-depleted IL-10-/- mice were infected with C. jejuni strain 81-176 by gavage and orally treated with Aviguard® or placebo from day 2 to 4 post-infection. The applied probiotic bacteria could be rescued from the intestinal tract of treated mice, but with lower obligate anaerobic bacterial counts in C. jejuni-infected as compared to non-infected mice. Whereas comparable gastrointestinal pathogen loads could be detected in both groups until day 6 post-infection, Aviguard® treatment resulted in improved clinical outcome and attenuated apoptotic cell responses in infected large intestines during acute campylobacteriosis. Furthermore, less distinct pro-inflammatory immune responses could be observed not only in the intestinal tract, but also in extra-intestinal compartments on day 6 post-infection. In conclusion, we show here for the first time that Aviguard® exerts potent disease-alleviating effects in acute C. jejuni-induced murine enterocolitis and might be a promising probiotic treatment option for severe campylobacteriosis in humans.

Therapeutic effects of oral benzoic acid application during acute murine campylobacteriosis.

Serious risks to human health are posed by acute campylobacteriosis, an enteritis syndrome caused by oral infection with the food-borne bacterial enteropathogen Campylobacter jejuni. Since the risk for developing post-infectious autoimmune complications is intertwined with the severity of enteritis, the search of disease-mitigating compounds is highly demanded. Given that benzoic acid is an organic acid with well-studied health-promoting including anti-inflammatory effects we tested in our present study whether the compound might be a therapeutic option to alleviate acute murine campylobacteriosis. Therefore, microbiota-depleted IL-10-/- mice were perorally infected with C. jejuni and received benzoic acid through the drinking water from day 2 until day 6 post-infection. The results revealed that benzoic acid treatment did not affect C. jejuni colonization in the gastrointestinal tract, but alleviated clinical signs of acute campylobacteriosis, particularly diarrheal and wasting symptoms. In addition, benzoic acid mitigated apoptotic cell responses in the colonic epithelia and led to reduced pro-inflammatory immune reactions in intestinal, extra-intestinal, and systemic compartments tested on day 6 post-infection. Hence, our preclinical placebo-controlled intervention trial revealed that benzoic acid constitutes a promising therapeutic option for treating acute campylobacteriosis in an antibiotic-independent fashion and in consequence, also for reducing the risk of post-infectious autoimmune diseases.

Human microbiota associated IL-10-/- mice: A valuable enterocolitis model to dissect the interactions of Campylobacter jejuni with host immunity and gut microbiota.

Secondary abiotic (SAB) IL-10-/- mice constitute a valuable Campylobacter jejuni-induced enterocolitis model. Given that the host-specific gut microbiota plays a key role in susceptibility of the vertebrate host towards or resistance against enteropathogenic infection, we surveyed immunopathological sequelae of C. jejuni infection in human microbiota associated (hma) and SAB IL-10-/- mice. Following oral challenge, C. jejuni readily colonized the gastrointestinal tract of hma and SAB mice, but with lower numbers in the former versus the latter. Whereas hma mice were clinically less severely compromised, both, macroscopic and microscopic inflammatory sequelae of C. jejuni infection including histopathological and apoptotic cell responses in the colon of IL-10-/- mice were comparably pronounced in the presence and absence of a human gut microbiota at day 6 post-infection. Furthermore, C. jejuni infection of hma and SAB mice resulted in similarly enhanced immune cell responses in the colon and in differential pro-inflammatory mediator secretion in the intestinal tract, which also held true for extra-intestinal including systemic compartments. Notably, C. jeuni infection of hma mice was associated with distinct gut microbiota shifts. In conclusion, hma IL-10-/- mice represent a reliable C. jejuni-induced enterocolitis model to dissect the interactions of the enteropathogen, vertebrate host immunity and human gut microbiota.

Oral application of carvacrol, butyrate, ellagic acid, and 2'-fucosyl-lactose to mice suffering from acute campylobacteriosis - Results from a preclinical placebo-controlled intervention study.

Background: Acute campylobacteriosis caused by oral infections with the enteropathogen Campylobacter jejuni represent serious threats to global human health. Since novel treatment options with safe and antibiotics-independent compounds would be highly appreciable, we here investigated the anti-bacterial and disease-alleviating effects of carvacrol, butyrate, ellagic acid, and 2'-fucosyl-lactose in acute murine campylobacteriosis. To address this, secondary abiotic IL-10-/- mice were perorally infected with C. jejuni and treated with either compound alone or all four in combination via the drinking water starting two days post-infection. Results: On day 6, the duodenal pathogen loads were lower in mice of the combination versus the vehicle treatment cohort. Importantly, mice treated with carvacrol and the combination presented with less distinct diarrheal symptoms, colonic histopathology, epithelial cell apoptosis, and immune cell responses when compared to vehicle counterparts on day 6 post-infection. Furthermore, the combination treatment did not only diminish colonic IFN-γ, TNF-α, and IL-6 secretion in C. jejuni infected mice, but also dampened extra-intestinal and even systemic pro-inflammatory cytokine concentrations to basal levels as measured in liver, kidneys, lungs, and serum samples. Conclusions: Our preclinical placebo-controlled intervention trial provides evidence that the combined oral application of carvacrol, butyrate, ellagic acid, and 2'-fucosyl-lactose alleviates acute campylobacteriosis in the vertebrate host.

Iron Deprivation by Oral Deferoxamine Application Alleviates Acute Campylobacteriosis in a Clinical Murine Campylobacter jejuni Infection Model.

The progressively rising food-borne Campylobacter jejuni infections pose serious health problems and socioeconomic burdens. Given that antibiotic therapy is not recommended for most campylobacteriosis patients, novel treatment options include strategies targeting iron homeostasis that impacts both C. jejuni virulence and inflammatory cell damage caused by toxic oxygen species. In our preclinical intervention study, we tested potential disease-alleviating effects upon prophylactic oral application of the iron-chelating compound desferoxamine (DESF) in acute murine campylobacteriosis. Therefore, microbiota-depleted IL-10-/- mice received synthetic DESF via the drinking water starting seven days before oral infection with C. jejuni strain 81-176. Results revealed that the DESF application did not reduce gastrointestinal pathogen loads but significantly improved the clinical outcome of infected mice at day 6 post-infection. This was accompanied by less pronounced colonic epithelial cell apoptosis, attenuated accumulation of neutrophils in the infected large intestines and abolished intestinal IFN-γ and even systemic MCP-1 secretion. In conclusion, our study highlights the applied murine campylobacteriosis model as suitable for investigating the role of iron in C. jejuni infection in vivo as demonstrated by the disease-alleviating effects of specific iron binding by oral DESF application in acute C. jejuni induced enterocolitis.

Campylobacter jejuni infection induces acute enterocolitis in IL-10-/- mice pretreated with ampicillin plus sulbactam.

Gut microbiota depletion is a pivotal prerequisite to warrant Campylobacter jejuni infection and induced inflammation in IL-10-/- mice used as acute campylobacteriosis model. We here assessed the impact of an 8-week antibiotic regimen of ampicillin, ciprofloxacin, imipenem, metronidazole, and vancomycin (ABx) as compared to ampicillin plus sulbactam (A/S) on gut microbiota depletion and immunopathological responses upon oral C. jejuni infection. Our obtained results revealed that both antibiotic regimens were comparably effective in depleting the murine gut microbiota facilitating similar pathogenic colonization alongside the gastrointestinal tract following oral infection. Irrespective of the preceding microbiota depletion regimen, mice were similarly compromised by acute C. jejuni induced enterocolitis as indicated by comparable clinical scores and macroscopic as well as microscopic sequelae such as colonic histopathology and apoptosis on day 6 post-infection. Furthermore, innate and adaptive immune cell responses in the large intestines were similar in both infected cohorts, which also held true for intestinal, extra-intestinal and even systemic secretion of pro-inflammatory cytokines such as TNF-α, IFN-γ, and IL-6. In conclusion, gut microbiota depletion in IL-10-/- mice by ampicillin plus sulbactam is sufficient to investigate both, C. jejuni infection and the immunopathological features of acute campylobacteriosis.

Garlic Essential Oil as Promising Option for the Treatment of Acute Campylobacteriosis-Results from a Preclinical Placebo-Controlled Intervention Study.

Since human infections with Campylobacter jejuni including antibiotic-resistant strains are rising worldwide, natural compounds might constitute promising antibiotics-independent treatment options for campylobacteriosis. Since the health-beneficial properties of garlic have been known for centuries, we here surveyed the antimicrobial and immune-modulatory effects of garlic essential oil (EO) in acute experimental campylobacteriosis. Therefore, secondary abiotic IL-10-/- mice were orally infected with C. jejuni strain 81-176 and garlic-EO treatment via the drinking water was initiated on day 2 post-infection. Mice from the garlic-EO group displayed less severe clinical signs of acute campylobacteriosis as compared to placebo counterparts that were associated with lower ileal C. jejuni burdens on day 6 post-infection. Furthermore, when compared to placebo application, garlic-EO treatment resulted in alleviated colonic epithelia cell apoptosis, in less pronounced C. jejuni induced immune cell responses in the large intestines, in dampened pro-inflammatory mediator secretion in intestinal and extra-intestinal compartments, and, finally, in less frequent translocation of viable pathogens from the intestines to distinct organs. Given its potent immune-modulatory and disease-alleviating effects as shown in our actual preclinical placebo-controlled intervention study, we conclude that garlic-EO may be considered as promising adjunct treatment option for acute campylobacteriosis in humans.

Peroral Clove Essential Oil Treatment Ameliorates Acute Campylobacteriosis-Results from a Preclinical Murine Intervention Study.

Campylobacter (C.) jejuni infections pose progressively emerging threats to human health worldwide. Given the rise in antibiotic resistance, antibiotics-independent options are required to fight campylobacteriosis. Since the health-beneficial effects of clove have been known for long, we here analyzed the antimicrobial and immune-modulatory effects of clove essential oil (EO) during acute experimental campylobacteriosis. Therefore, microbiota-depleted interleukin-10 deficient (IL-10-/-) mice were perorally infected with C. jejuni and treated with clove EO via drinking water starting on day 2 post-infection. On day 6 post-infection, lower small- and large-intestinal pathogen loads could be assessed in clove EO as compared to placebo treated mice. Although placebo mice suffered from severe campylobacteriosis as indicated by wasting and bloody diarrhea, clove EO treatment resulted in a better clinical outcome and in less severe colonic histopathological and apoptotic cell responses in C. jejuni infected mice. Furthermore, lower colonic numbers of macrophages, monocytes, and T lymphocytes were detected in mice from the verum versus the placebo cohort that were accompanied by lower intestinal, extra-intestinal, and even systemic proinflammatory cytokine concentrations. In conclusion, our preclinical intervention study provides first evidence that the natural compound clove EO constitutes a promising antibiotics-independent treatment option of acute campylobacteriosis in humans.

Resveratrol Alleviates Acute Campylobacter jejuni Induced Enterocolitis in a Preclinical Murine Intervention Study.

The polyphenolic compound resveratrol has been shown to exert health-beneficial properties. Given globally emerging Campylobacter infections in humans, we addressed potential anti-pathogenic, immuno-modulatory and intestinal epithelial barrier preserving properties of synthetic resveratrol in the present preclinical intervention study applying a murine acute campylobacteriosis model. Two days following peroral C. jejuni infection, secondary abiotic IL-10-/- mice were either subjected to resveratrol or placebo via the drinking water. Whereas placebo mice suffered from acute enterocolitis at day 6 post-infection, resveratrol treatment did not only lead to improved clinical conditions, but also to less pronounced colonic epithelial apoptosis as compared to placebo application. Furthermore, C. jejuni induced innate and adaptive immune cell responses were dampened in the large intestines upon resveratrol challenge and accompanied by less colonic nitric oxide secretion in the resveratrol versus the placebo cohort. Functional analyses revealed that resveratrol treatment could effectively rescue colonic epithelial barrier function in C. jejuni infected mice. Strikingly, the disease-alleviating effects of resveratrol could additionally be found in extra-intestinal and also systemic compartments at day 6 post-infection. For the first time, our current preclinical intervention study provides evidence that peroral resveratrol treatment exerts potent disease-alleviating effects during acute experimental campylobacteriosis.

Pituitary Adenylate Cyclase-Activating Polypeptide Alleviates Intestinal, Extra-Intestinal and Systemic Inflammatory Responses during Acute Campylobacter jejuni-induced Enterocolitis in Mice.

Human Campylobacter jejuni infections are emerging, and constitute a significant health burden worldwide. The ubiquitously expressed pituitary adenylate cyclase-activating polypeptide (PACAP) is well-known for its cell-protective and immunomodulatory effects. In our actual intervention study, we used an acute campylobacteriosis model and assessed the potential disease-alleviating effects of exogenous PACAP. Therefore, secondary abiotic IL-10-/- mice were perorally infected with C. jejuni and treated with synthetic PACAP38 intraperitoneally from day 2 until day 5 post-infection. Whereas PACAP did not interfere with the gastrointestinal colonization of the pathogen, mice from the PACAP group exhibited less severe clinical signs of C. jejuni-induced disease, as compared to mock controls, which were paralleled by alleviated apoptotic, but enhanced cell proliferative responses in colonic epithelia on day 6 post-infection. Furthermore, PACAP dampened the accumulation of macrophages and monocytes, but enhanced regulatory T cell responses in the colon, which were accompanied by less IFN-γ secretion in intestinal compartments in PACAP versus mock-treated mice. Remarkably, the inflammation-dampening properties of PACAP could also be observed in extra-intestinal organs, and strikingly, even the systemic circulation on day 6 post-infection. For the first time, we provide evidence that synthetic PACAP might be a promising candidate to combat acute campylobacteriosis and post-infectious sequelae.

Immune-modulatory Properties of the Octapeptide NAP in Campylobacter jejuni Infected Mice Suffering from Acute Enterocolitis.

Human infections with the food-borne zoonotic pathogen Campylobacter jejuni are progressively rising and constitute serious global public health and socioeconomic burdens. Hence, application of compounds with disease-alleviating properties are required to combat campylobacteriosis and post-infectious sequelae. In our preclinical intervention study applying an acute C. jejuni induced enterocolitis model, we surveyed the anti-pathogenic and immune-modulatory effects of the octapeptide NAP which is well-known for its neuroprotective and anti-inflammatory properties. Therefore, secondary abiotic IL-10-/- mice were perorally infected with C. jejuni and intraperitoneally treated with synthetic NAP from day 2 until day 5 post-infection. NAP-treatment did not affect gastrointestinal C. jejuni colonization but could alleviate clinical signs of infection that was accompanied by less pronounced apoptosis of colonic epithelial cells and enhancement of cell regenerative measures on day 6 post-infection. Moreover, NAP-treatment resulted in less distinct innate and adaptive pro-inflammatory immune responses that were not restricted to the intestinal tract but could also be observed in extra-intestinal and even systemic compartments. NAP-treatment further resulted in less frequent translocation of viable pathogens from the intestinal tract to extra-intestinal including systemic tissue sites. For the first time, we here provide evidence that NAP application constitutes a promising option to combat acute campylobacteriosis.