Assessment of the Inflammatory Effects of Gut Microbiota from Human Twins Discordant for Ulcerative Colitis on Germ-free Mice

Disturbances in gut microbiota are prevalent in inflammatory bowel disease (IBD), which includes ulcerative colitis (UC). However, whether these disturbances contribute to development of the disease or are a result of the disease is unclear. In pairs of human twins discordant for IBD, the healthy twin has a higher risk of developing IBD and a gut microbiota that is more similar to that of IBD patients as compared with healthy individuals. Furthermore, appropriate medical treatment may mitigate these disturbances. To study the correlation between microbiota and IBD, we transferred stool samples from a discordant human twin pair: one twin being healthy and the other receiving treatment for UC. The stool samples were transferred from the disease-discordant twins to germ-free pregnant dams. Colitis was induced in the offspring using dextran sodium sulfate. As compared with offspring born to mice dams inoculated with stool from the healthy cotwin, offspring born to dams inoculated with stool from the UC-afflicted twin had a lower disease activity index, less gut inflammation, and a microbiota characterized by higher α diversity and a more antiinflammatory profile that included the presence and higher abundance of antiinflammatory species such as Akkermansia spp., Bacteroides spp., and Parabacteroides spp. These findings suggest that the microbiota from the healthy twin may have had greater inflammatory properties than did that of the twin undergoing UC treatment.

Strong Response to SARS-CoV-2 Vaccine Additional Doses Among Patients With Inflammatory Bowel Diseases

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has disrupted health care and has resulted in high mortality rates.¹ Vaccination is an international priority to mitigate the risks of SARS-CoV-2. The initial trials for development of SARS-CoV-2 vaccines excluded individuals with immunocompromising conditions.².

COVID-19 Outcomes Among Racial and Ethnic Minority Individuals With Inflammatory Bowel Disease in the United States

The coronavirus disease 2019 (COVID-19) has affected more than 29 million people and led to more than 542,000 deaths in the United States.1 Older age, comorbidities, and racial and ethnic minority status are associated with severe COVID-19.2 Among patients with inflammatory bowel disease (IBD), racial and ethnic minorities have worse outcomes, mediated in part by inequitable health care access.3 Racial and ethnic minority patients with IBD and COVID-19 may be an especially vulnerable population. The purpose of this study was to evaluate racial and ethnic disparities in COVID-19 outcomes among IBD patients and the impact of non-IBD comorbidities on observed disparities.

A comprehensive guide to the pharmacologic regulation of angiotensin converting enzyme 2 (ACE2), the SARS-CoV-2 entry receptor

The recent emergence of coronavirus disease-2019 (COVID-19) as a global pandemic has prompted scientists to address an urgent need for defining mechanisms of disease pathology and treatment. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent for COVID-19, employs angiotensin converting enzyme 2 (ACE2) as its primary target for cell surface attachment and likely entry into the host cell. Thus, understanding factors that may regulate the expression and function of ACE2 in the healthy and diseased body is critical for clinical intervention. Over 66% of all adults in the United States are currently using a prescription drug and while earlier findings have focused on possible upregulation of ACE2 expression through the use of renin angiotensin system (RAS) inhibitors, mounting evidence suggests that various other widely administered drugs used in the treatment of hypertension, heart failure, diabetes mellitus, hyperlipidemias, coagulation disorders, and pulmonary disease may also present a varied risk for COVID-19. Specifically, we summarize mechanisms on how heparin, statins, steroids and phytochemicals, besides their established therapeutic effects, may also interfere with SARS-CoV-2 viral entry into cells. We also describe evidence on the effect of several vitamins, phytochemicals, and naturally occurring compounds on ACE2 expression and activity in various tissues and disease models. This comprehensive review aims to provide a timely compendium on the potential impact of commonly prescribed drugs and pharmacologically active compounds on COVID-19 pathology and risk through regulation of ACE2 and RAS signaling.

A One Health Perspective for Defining and Deciphering Escherichia coli Pathogenic Potential in Multiple Hosts

E. coli is one of the most common species of bacteria colonizing humans and animals. The singularity of E. coli 's genus and species underestimates its multifaceted nature, which is represented by different strains, each with different combinations of distinct virulence factors. In fact, several E. coli pathotypes, or hybrid strains, may be associated with both subclinical infection and a range of clinical conditions, including enteric, urinary, and systemic infections. E. coli may also express DNA-damaging toxins that could impact cancer development. This review summarizes the different E. coli pathotypes in the context of their history, hosts, clinical signs, epidemiology, and control. The pathotypic characterization of E. coli in the context of disease in different animals, including humans, provides comparative and One Health perspectives that will guide future clinical and research investigations of E. coli infections.

Benign Evolution of SARS-Cov2 Infections in Children With Inflammatory Bowel Disease: Results From Two International Databases

The coronavirus disease 2019 (COVID-19) pandemic caused by the highly infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents most often with mild clinical symptoms, but the severe forms are of major concern.¹ SARS-CoV-2 enters human cells via the angiotensin-converting enzyme 2 receptor, expressed on epithelial and endothelial cells.² Because the highest angiotensin-converting enzyme 2 expression is in the terminal ileum and colon, and up-regulated further during inflammation, and many COVID-19 patients experience gastrointestinal symptoms, longitudinal data are necessary to determine whether inflammatory bowel disease (IBD) patients are at risk for severe or complicated COVID-19. A recent analysis in IBD patients from the Surveillance Epidemiology of Coronavirus Under Research Exclusion for Inflammatory Bowel Disease (SECURE-IBD) registry showed older age, steroid medication, and comorbidities as risk factors for severe evolution, and the same study showed that the 29 IBD patients younger than age 20 had only mild disease courses.³ This report describes the disease course of COVID-19 in an expanded sample of pediatric IBD patients from 2 international databases.

Autologous fecal microbiota transplantation for the treatment of inflammatory bowel disease

The term autologous fecal microbiota transplantation (a-FMT) refers herein to the use of one's feces during a healthy state for later use to restore gut microbial communities after perturbations. Generally, heterologous fecal microbiota transplantation (h-FMT), where feces from a ``healthy" donor is transplanted into a person with illness, has been used to treat infectious diseases such as recurrent Clostridioides difficile infection (CDI), with cure rates of up to 90%. In humans, due to limited response to medicines, h-FMT has become a hallmark intervention to treat CDI. Extrapolating the benefits from CDI, h-FMT has been attempted in various diseases, including inflammatory bowel disease (IBD), but clinical response has been variable and less effective (ranging between 24% and 50%). Differences in h-FMT clinical response could be because CDI is caused by a Clostridial infection, whereas IBD is a complex, microbiome-driven immunological inflammatory disorder that presents predominantly within the gut wall of genetically-susceptible hosts. FMT response variability could also be due to differences in microbiome composition between donors, recipients, and within individuals, which vary with diet, and environments, across regions. While donor selection has emerged as a key factor in FMT success, the use of heterologous donor stool still places the recipient at risk of exposure to infectious/pathogenic microorganisms. As an implementable solution, herein we review the available literature on a-FMT, and list some considerations on the benefits of a-FMT for IBD.

Incidence and Patterns of COVID-19 Among Inflammatory Bowel Disease Patients From the Nancy and Milan Cohorts

The first cases of COVID-19 infection were reported in December, 2019, in Wuhan, China. Italy (in particular Lombardy) and France (in particular Northeast) have been gravely hit. Both physicians and inflammatory bowel disease (IBD) patients are deeply concerned that immunosuppressants or biologics may increase the risk of COVID-19 infection. IOIBD has put in place an international registry, SECURE-IBD, for tracking all the cases with IBDs infected by COVID-19 (SECURE-IBD registry: http://www.covidibd.org). It will describe the outcomes of infected patients and the association between IBD-related medications and these outcomes.

Maintaining the Quality Standards of Care for Inflammatory Bowel Disease Patients During the COVID-19 Pandemic

Since February 20, 2020, the SARS-COV2 infection has spread in Lombardy, and in the rest of the Italian regions, forcing our government to impose a national lockdown.¹ Hospitals have been forced to adapt and to restructure their units to cope with this urgent new critical situation.² Alternative solutions have been found to manage patients with inflammatory bowel disease (IBD), including remote monitoring, drug home delivery, limitations for infusion units, and patient education on measures to prevent infection,³ to maintain high-quality care.⁴.

Effect of Chronic Vitamin D Deficiency on the Development and Severity of DSS-Induced Colon Cancer in Smad3-/- Mice

Both human epidemiologic data and animal studies suggest that low serum vitamin D increases the risk of inflammatory bowel disease (IBD) and consequently IBD-associated colorectal cancer. We tested the hypothesis that vitamin D deficiency increases the risk for colitis-associated colon cancer (CAC) by using an established CAC mouse model, 129-Smad3tm1Par/J (Smad3-/-) mice, which have defective transforming growth factor β-signaling and develop colitis and CAC after the administration of dextran sodium sulfate (DSS). After determining a dietary regimen that induced chronic vitamin D deficiency in Smad3-/- mice, we assessed the effects of vitamin D deficiency on CAC. Decreasing dietary vitamin D from 1 IU/g diet (control diet) to 0.2 IU /g diet did not decrease serum 25-hydroxyvitamin D (25(OH)D) levels in Smad3-/- mice. A diet devoid of vitamin D (< 0.02 IU/g diet [no added vitamin D]; vitamin D-null) significantly decreased serum 25(OH)D levels in mice after 2 wk (null compared with control diet: 8.4 mg/mL compared with 12.2 ng/mL) and further decreased serum levels to below the detection limit after 9 wk but did not affect weight gain, serum calcium levels, bone histology, or bone mineral density. In light of these results, Smad3-/- mice were fed a vitamin D-null diet and given DSS to induce colitis. Unexpectedly, DSS-treated Smad3-/- mice fed a vitamin D-null diet had improved survival, decreased colon tumor incidence (8% compared with 36%), and reduced the incidence and severity of colonic dysplasia compared with mice fed the control diet. These effects correlated with increased epithelial cell proliferation and repair early in the disease, perhaps reducing the likelihood of developing chronic colitis and progression to cancer. Our results indicate that vitamin D deficiency is beneficial in some cases of CAC, possibly by promoting intestinal healing.

Lack of Effect of Murine Norovirus Infection on the CD4+ CD45RBhigh T-cell Adoptive Transfer Mouse Model of Inflammatory Bowel Disease

Murine norovirus (MNV) infection is highly prevalent in laboratory mice. Although MNV infection does not typically induce clinical disease in most laboratory mice, infection may nonetheless affect mouse models of disease by altering immune responses. We previously reported that MNV altered the bacterial-induced mouse model of inflammatory bowel disease (IBD) using Helicobacter-infected Mdr1a-/- mice. Therefore, we hypothesized that MNV infection would exacerbate another mouse model of IBD, the T-cell adoptive transfer (AT) model. In this model, Helicobacter infection is used to accelerate the progression of IBD induced by AT of naïve CD4+CD45RBhigh T cells into B6.129S7- Rag1tm1Mom/J (Rag1-/-) mice. We evaluated the effects of MNV infection in both Helicobacter-accelerated as well as Helicobacter-free AT models. In our studies, Helicobacter-infected Rag1-/- mice that received CD4+CD45RBhigh T cells through AT rapidly developed weight loss and typhlocolitis; MNV infection had no effect on disease severity or rate of progression. In the absence of Helicobacter infection, progression of IBD caused by AT of CD4+CD45RBhigh T cells was slower and typhlocolitis was less severe; this inflammation likewise was unaltered by MNV infection. These results indicate that MNV infection does not alter IBD progression and severity in the CD4+CD45RBhigh T-cell AT model in Rag1-/- mice.

A Review of the Effects of Pain and Analgesia on Immune System Function and Inflammation: Relevance for Preclinical Studies

One of the most significant challenges facing investigators, laboratory animal veterinarians, and IACUCs, is how to balance appropriate analgesic use, animal welfare, and analgesic impact on experimental results. This is particularly true for in vivo studies on immune system function and inflammatory disease. Often times the effects of analgesic drugs on a particular immune function or model are incomplete or don't exist. Further complicating the picture is evidence of the very tight integration and bidirectional functionality between the immune system and branches of the nervous system involved in nociception and pain. These relationships have advanced the concept of understanding pain as a protective neuroimmune function and recognizing pathologic pain as a neuroimmune disease. This review strives to summarize extant literature on the effects of pain and analgesia on immune system function and inflammation in the context of preclinical in vivo studies. The authors hope this work will help to guide selection of analgesics for preclinical studies of inflammatory disease and immune system function.

Defining the Therapeutic Range for Adalimumab and Predicting Response in Psoriasis: A Multicenter Prospective Observational Cohort Study

Biologics have transformed management of inflammatory diseases. To optimize outcomes and reduce costs, dose adjustment informed by circulating drug levels has been proposed. We aimed to determine the real-world clinical utility of therapeutic drug monitoring in psoriasis. Within a multicenter (n = 60) prospective observational cohort, 544 psoriasis patients were included who were receiving adalimumab monotherapy and had at least one serum sample and Psoriasis Area and Severity Index (PASI) score available within the first year. We present models giving individualized probabilities of response for any given drug level: a minimally effective drug level of 3.2 μg/ml discriminates responders (PASI75 indicates 75% improvement in baseline PASI) from nonresponders, and gives an estimated PASI75 probability of 65% (95% confidence interval = 60-71). At 7 μg/ml, PASI75 probability is 81% (95% CI = 76-86); beyond 7 μg/ml, the drug level/response curve plateaus. Crucially, drug levels are predictive of response 6 months later, whether sampled early or at steady state. We confirm serum drug level to be the most important factor determining treatment response, highlighting the need to take drug levels into account when searching for biomarkers of response. This real-world study with pragmatic drug level sampling provides evidence to support the proactive measurement of adalimumab levels in psoriasis to direct treatment strategy, and is relevant to other inflammatory diseases.

Maintaining intestinal health: the genetics and immunology of very early onset inflammatory bowel disease

Inflammatory bowel disease (IBD) is a multifactoral disease caused by dysregulated immune responses to commensal or pathogenic microbes in the intestine, resulting in chronic intestinal inflammation. An emerging population of patients with IBD occurring before the age of 5 represent a unique form of disease, termed Very Early Onset (VEO)-IBD, which is phenotypically- and genetically-distinct from older-onset IBD. VEO-IBD is associated with increased disease severity, aggressive progression and poor responsiveness to most conventional therapies. Further investigation into the causes and pathogenesis of VEO-IBD will help improve treatment strategies, and may lead to a better understanding of the mechanisms that are essential to maintain intestinal health or provoke the development of targeted therapeutic strategies to limit intestinal disease. Here we discuss the phenotypic nature of VEO-IBD, the recent identification of novel gene variants associated with disease, and functional immunologic studies interrogating the contribution of specific genetic variants to the development of chronic intestinal inflammation.

The gut microbiota and liver disease

The leaky gut hypothesis links translocating microbial products with the onset and progression of liver disease, and for a long time was considered one of its major contributors. However, a more detailed picture of the intestinal microbiota contributing to liver disease started to evolve. The gut is colonized by trillions of microbes that aid in digestion, modulate immune response, and generate a variety of products that result from microbial metabolic activities. These products together with host-bacteria interactions influence both normal physiology and disease susceptibility. A disruption of the symbiosis between microbiota and host is known as dysbiosis and can have profound effects on health. Qualitative changes such as increased proportions of harmful bacteria and reduced levels of beneficial bacteria, and also quantitative changes in the total amount of bacteria (overgrowth) have been associated with liver disease. Understanding the link between the pathophysiology of liver diseases and compositional and functional changes of the microbiota will help in the design of innovative therapies. In this review, we focus on factors resulting in dysbiosis, and discuss how dysbiosis can disrupt intestinal homeostasis and contribute to liver disease.

Infection with murine norovirus 4 does not alter Helicobacter-induced inflammatory bowel disease in Il10(-/-) mice

Infection of laboratory mice with murine noroviruses (MNV) is widely prevalent. MNV alters various mouse models of disease, including the Helicobacter bilis-induced mouse model of inflammatory bowel disease (IBD) in Mdr1a(--) mice. To further characterize the effect of MNV on IBD, we used mice deficient in the immunoregulatory cytokine IL10 (Il10(-/-) mice). In vitro infection of Il10(-/-) bone marrow-derived macrophages (BMDM) with MNV4 cocultured with H. bilis antigens increased the gene expression of the proinflammatory cytokines IL1β, IL6, and TNFα as compared with that of BMDM cultured with H. bilis antigens only. Therefore, to test the hypothesis that MNV4 infection increases inflammation and alters disease phenotype in H. bilis-infected Il10(-/-) mice, we compared the amount and extent of inflammation in Il10(-/-) mice coinfected with H. bilis and MNV4 with those of mice singly infected with H. bilis. IBD scores, incidence of IBD, or frequency of severe IBD did not differ between mice coinfected with H. bilis and MNV4 and those singly infected with H. bilis. Mice infected with MNV4 only had no appreciable IBD, comparable to uninfected mice. Our findings suggest that, unlike in Mdr1a(-/-) mice, the presence of MNV4 in Il10(-/-) mouse colonies is unlikely to affect the IBD phenotype in a Helicobacter-induced model. However, because MNV4 altered cytokine expression in vitro, our results highlight the importance of determining the potential influence of MNV on mouse models of inflammatory disease, given that MNV has a tropism for macrophages and dendritic cells and that infection is widely prevalent.

Isolation of Helicobacter spp. from mice with rectal prolapses

Enterohepatic Helicobacter species (EHS) often are associated with typhlocolitis and rectal prolapse in mice. We sought to describe rectal prolapses histologically, relate lesions to mouse genotype and EHS infection status, and characterize EHS pathogens on our campus. Our mouse population was housed among 6 facilities on our main campus and a seventh, nearby facility. We investigated cases of rectal prolapse over 1 y and included 76 mice, which were broadly categorized according to genotype. Microscopically, lesions ranged from mild to severe typhlocolitis, often with hyperplastic and dysplastic foci. Neoplastic foci tended to occur at the ileocecal-colic junction. Lesions were most severe in strains that had lower-bowel inflammatory disease, notably IL10, Rag1, and Rag2 knockout strains; prolapses occurred in these strains when housed both in areas with endemic EHS and in our Helicobacter-free barrier facility. Most mice with rectal prolapses were immunocompromised genetically modified mice; however, the most frequently sampled strain, the lamellipodin knockout, was noteworthy for its high incidence of rectal prolapse, localized distal colonic and rectal lesions, and lack of known immunodeficiency. This strain is being explored as a model of rectal carcinoma. Most of the colons examined tested PCR-positive for EHS, often with coinfections. Although H. bilis is prevalent on our campus, we did not find this organism in any mice exhibiting clinical signs of rectal prolapse. Identification of H. apodemus in 22% of cases has fueled increased surveillance on our campus to characterize this organism and differentiate it from the closely related H. rodentium.

Effects of medicated diet to eradicate Helicobacter spp. on growth, pathology, and infection status in Rag1-/- and nude mice

The use of a commercial 4-drug diet has been shown to eradicate Helicobacter spp. from immunocompetent mice and those with innate immunodeficiencies. However the efficacy of this diet has not been confirmed in mice with altered adaptive immunity. We hypothesized that an 8-wk treatment with medicated diet would eradicate H. hepaticus and H. typhlonius from young naturally infected nude and Rag1 mice lacking functional T cells (Foxn1(nu)) or T and B cells (B6.129S7-Rag1(tm1Mom)/J), respectively. We evaluated helicobacter status, body weight, and gross and histologic changes between medicated and control diet in groups of infected and uninfected mice throughout treatment and at 8 wk after treatment completion. Initial infection status was confirmed by fecal PCR at weaning and 3 wk later, with study initiation in 7-wk-old mice. PCR testing demonstrated that independent of strain and sex, all treated mice tested negative for Helicobacter spp. after 4 wk of treatment and remained negative for the duration of the study. Irrespective of infection status, nude and Rag1 mice fed 8 wk of medicated diet gained less weight than did their untreated controls. Both strains normalized body weight while on control diet for the 8 wk after treatment. Mice fed medicated diet developed severe gastroesophageal hyperkeratosis, suggestive of reduced feed consumption, and enlarged ceca. These conditions improved or resolved after the return to control diet. This report is the first to demonstrate the efficacy and physical effects of providing medicated diet for the eradication of Helicobacter spp. from mice with adaptive immune deficiencies.

Long-term medical management of the liver transplant recipient: what the primary care physician needs to know

Recognition, management, and prevention of medical complications and comorbidities after liver transplant is the key to improved long-term outcomes. Beyond allograft-related complications, metabolic syndrome, cardiovascular disease, renal dysfunction, and malignancies are leading causes of morbidity and mortality in this patient population. Primary care physicians have an important role in improving outcomes of liver transplant recipients and are increasingly relied on for managing these complex patients. This review serves to assist the primary care physician in the long-term management issues of liver transplant recipients.

Vasculitis associated with tumor necrosis factor-α inhibitors

OBJECTIVE

To describe the clinical characteristics, histopathologic features, and outcomes of patients in whom vasculitis developed in association with use of tumor necrosis factor-α (TNF-α) inhibitors.

PATIENTS AND METHODS

This is a retrospective review of patients evaluated at Mayo Clinic, Rochester, Minnesota, from January 1, 1998, through March 31, 2011, with a diagnosis of vasculitis induced by anti-TNF-α therapy.

RESULTS

Of 8 patients with vasculitis associated with anti-TNF-α therapy (mean age, 48.5 years), 6 (75%) were female. Four (50%) had rheumatoid arthritis, 1 (13%) had Crohn disease, and 3 (38%) had ulcerative colitis. Five (63%) were treated with infliximab, 2 (25%) with etanercept, and 1 (13%) with adalimumab. The mean duration of treatment before development of vasculitis was 34.5 months. The skin was the predominant organ affected (5 patients [63%]), with the most common cutaneous lesion being palpable purpura (4 of 5 [80%]). Two organs involved in systemic vasculitis were the peripheral nervous system (4 patients [50%]) and kidney (1 patient [13%]). All cases of vasculitis were histopathologically confirmed. Seven of 8 patients improved with discontinuation of therapy (mean time to resolution, 6.9 months) and adjuvant treatment (all 8 received prednisone; another agent was also used in 7); rechallenge with anti-TNF-α therapy was not attempted in any patient. At last follow-up, no patients had experienced a recurrence of vasculitis after therapy discontinuation.

CONCLUSION

Cutaneous small-vessel vasculitis was the most common finding, but systemic vasculitis, including peripheral nerve and renal vasculitis, was also frequently observed.

Lack of effect of murine norovirus infection on a mouse model of bacteria-induced colon cancer

Murine norovirus (MNV) is endemic in mouse research facilities in the United States and Europe, with a prevalence as high as 58% to 64%. Because of MNV's orofecal route of infection, clinically silent persistent infections in some mouse strains, and proclivity for macrophage and dendritic cells, its presence in mouse colonies has potential to alter phenotypes in experimental mouse models, particularly those involving inflammation and immunologic responses. Although MNV is subclinical, not causing overt disease in immunocompetent mice, we found that MNV infection can accelerate bacteria-induced inflammatory bowel disease (IBD) progression in Mdr1a(-/-) mice. The studies presented here examined whether MNV infection also affects the phenotype of a bacterially driven mouse model of inflammation-associated colon cancer in genetically susceptible Smad3(-/-) mice. In vitro culture of bone-marrow-derived macrophages (BMDM) was used to determine whether MNV4 influenced macrophage cytokine production. For in vivo studies, Smad3(-/-) mice were infected with MNV4 one week prior to infection with Helicobacter. Mice were monitored for 17 to 32 wk for development of IBD and colon cancer, and tissues were analyzed histopathologically. Although in vitro infection of BMDM with MNV4 led to increased inflammatory cytokine production, infection with MNV4 in vivo did not result in any statistically significant differences in survival, IBD scores, tumor incidence, or tumor phenotype in Smad3(-/-) mice. In addition, MNV infection alone did not result in IBD or colon cancer. Therefore MNV infection alone or in conjunction with Helicobacter does not alter the development or progression of IBD or colon cancer in Smad3(-/-) mice.

Intestinal cytokine mRNA expression in canine inflammatory bowel disease: a meta-analysis with critical appraisal

Data implicating mucosal cytokines in the pathogenesis of canine inflammatory bowel disease (IBD) are limited. The aims of the present study were to report new findings of intestinal cytokine expression in dogs with IBD and to compare these data with previous studies through meta-analysis. Cytokine mRNA abundance in intestinal biopsies collected prospectively was evaluated by using a semiquantitative RT-PCR technique. For meta-analysis, an electronic database search revealed 3 clinical trials, all of which were nonrandomized (type III) case series. Prospective analysis showed that the intestines of healthy dogs and those with IBD express numerous cytokines and that a proinflammatory expression profile is not a feature of small or large-intestinal IBD. The meta-analysis data included 158 dogs characterized as healthy (n = 45), diarrheic nonIBD dogs (n = 6), nonresponders (n = 2), small-intestinal IBD (n = 41), colonic IBD (n = 25), and chronic enteropathy (n = 39). German shepherd dogs were overrepresented in 3 of the 4 studies. Healthy dogs showed mRNA expression for most cytokines including IL2, IL4, IL5, IL10, IL12, IFNgamma, TNFalpha, and TGFbeta. Only IL12 mRNA expression was increased consistently in small-intestinal IBD, whereas IBD colitis lacked consistent patterns of expression. In summary, dogs with IBD fail to express a predominant Th1- or Th2 cytokine bias in inflamed mucosa. Heterogeneity of results among these studies might be explained by numerous factors including the method of mRNA quantification, stage of disease, and demographic differences in study populations.

Murine norovirus: an intercurrent variable in a mouse model of bacteria-induced inflammatory bowel disease

Murine norovirus (MNV) has recently been recognized as a widely prevalent viral pathogen in mouse colonies and causes disease and mortality in mice with impaired innate immunity. We tested the hypothesis that MNV infection would alter disease course and immune responses in mice with inflammatory bowel disease (IBD). FVB.129P2-Abcb1a(tm1Bor) N7 (Mdr1a-/-) mice develop spontaneous IBD that is accelerated by infection with Helicobacter bilis. As compared with controls, Mdr1a-/- mice coinfected with MNV4 and H. bilis showed greater weight loss and IBD scores indicative of severe colitis, demonstrating that MNV4 can modulate the progression of IBD. Compared with controls, mice inoculated with MNV4 alone had altered levels of serum biomarkers, and flow cytometric analysis of immune cells from MNV4-infected mice showed changes in both dendritic cell (CD11c+) and other nonT cell (CD4- CD8-) populations. Dendritic cells isolated from MNV4-infected mice induced higher IFNgamma production by polyclonal T cells in vitro at 2 d after infection but not at later time points, indicating that MNV4 infection enhances antigen presentation by dendritic cells early after acute infection. These findings indicate that acute infection with MNV4 is immunomodulatory and alters disease progression in a mouse model of IBD.

Helicobacter typhlonius and Helicobacter rodentium differentially affect the severity of colon inflammation and inflammation-associated neoplasia in IL10-deficient mice

Infection with Helicobacter species is endemic in many animal facilities and may alter the penetrance of inflammatory bowel disease (IBD) phenotypes. However, little is known about the relative pathogenicity of H. typhlonius, H. rodentium, and combined infection in IBD models. We infected adult and neonatal IL10-/- mice with H. typhlonius, H. rodentium, or both bacteria. The severity of IBD and incidence of inflammation-associated colonic neoplasia were assessed in the presence and absence of antiHelicobacter therapy. Infected IL10-/- mice developed IBD with severity of noninfected (minimal to no inflammation) < H. rodentium < H. typhlonius <mixed H. rodentium + H. typhlonius (severe inflammation). Inflammation-associated colonic neoplasia was common in infected mice and its incidence correlated with IBD severity. Combined treatment with amoxicillin, clarithromycin, metronidazole, and omeprazole eradicated Helicobacter in infected mice and ameliorated established IBD in both infected and noninfected mice. Infection of IL10-/- mice with H. rodentium, H. typhlonius, or both organisms can trigger development of severe IBD that eventually leads to colonic neoplasia. The high incidence and multiplicity of neoplastic lesions in infected mice make this model well-suited for future research related to the development and chemoprevention of inflammation-associated colon cancer. The similar antiinflammatory effect of antibiotic therapy in Helicobacter-infected and -noninfected IL10-/- mice with colitis indicates that unidentified microbiota in addition to Helicobacter drive the inflammatory process in this model. This finding suggests a complex role for both Helicobacter and other intestinal microbiota in the onset and perpetuation of IBD in these susceptible hosts.

Effects of the macrolide drug tylosin on chronic diarrhea in rhesus macaques (Macaca mulatta)

Diarrhea is the gastrointestinal disease most frequently encountered in captive rhesus macaques. The precise pathogenic mechanisms underlying chronic diarrhea in nonhuman primates are not well understood, but a persistent inflammatory component has been implicated strongly. This study evaluated the inflammatory changes in the colon of macaques with diarrhea and assessed the efficacy of a 10-d course of tylosin in a cohort of 21 animals with chronic diarrhea. Stool quality was evaluated daily, and fecal consistency was scored. Colonoscopies were performed; biopsy samples were characterized histologically and assayed for expression of TNFalpha mRNA. Blood samples collected pre-, mid-, and post-treatment were assayed for C-reactive protein (CRP). The results indicated that 63% of the animals receiving tylosin showed improvement in stool quality, compared with 10% in the sham-treated group. Histologically, 82% of animals in the tylosin-treated group had a reduction in the severity of colonic lesions post-treatment, compared with 40% of animals in the sham group. The amount of TNFalpha mRNA before treatment did not differ from that afterward in either tylosin- or sham-treated animals. CRP levels serially decreased in tylosin-treated monkeys; the average post-treatment CRP value for tylosin-treated animals was 11.96 +/- 3.86 microg/ml compared with 26.48 +/- 4.86 microg/ml for sham-treated controls. In conclusion, tylosin significantly improved the fecal consistency score, significantly decreased colonic inflammation, and significantly decreased serum CRP levels post-treatment in rhesus macaques with chronic diarrhea.

Hypoxia inducible factor 1alpha and 2alpha overexpression in inflammatory bowel disease

AIMS

Hypoxia inducible factors 1alpha and 2alpha (HIF1alpha and HIF2alpha) are hypoxia regulated transcriptional factors, which control the expression of a variety of genes responsible for angiogenesis, glycolysis, and the inhibition of apoptosis. Because angiogenesis and tissue regeneration are integral components of the inflammatory process, this study was designed to investigate the role of HIFalpha molecules in inflammatory bowel disease.

METHODS

Surgical specimens from patients with active ulcerative colitis (UC) and Crohn's disease (CD) were assessed immunohistochemically for HIF1alpha and HIF2alpha reactivity, and the expression of these molecules was compared with the expression of the angiogenic factors thymidine phosphorylase (TP), vascular endothelial growth factor (VEGF), and VEGF-KDR activated vasculature. The vascular density of the lesions was also assessed using anti-CD31 immunostaining.

RESULTS

HIF1alpha was expressed focally (epithelial cells, stromal fibroblasts, and myocytes) in both UC and CD, whereas HIF2alpha was expressed focally in UC and diffusely in CD. TP expression was uniformly positive in both diseases. VEGF expression was absent in CD, and weakly positive in UC. The VEGF-KDR reactivity of the submucosal vasculature was only slightly increased in UC and CD compared with normal tissue. The inflammatory cells stained with HIF2alpha and TP in all cases, but the reactivity was generalised in CD and focal in UC. In both diseases, vascular density was significantly higher than that seen in normal tissue.

CONCLUSIONS

The discordant expression of HIF2alpha and VEGF in CD suggests an inherent deficiency of the intestine to respond to various stresses by the induction of VEGF. This finding should be investigated further.