Pericholangitis in a rabbit colitis model induced by injection of muramyl dipeptide emulsified with a long-chain fatty acid

The Oral-Gut Axis: Periodontal Diseases and Gastrointestinal Disorders

One of the prospective sequelae of periodontal disease (PD), chronic inflammation of the oral mucosa, is the development of inflammatory gastrointestinal (GI) disorders due to the amplification and expansion of the oral pathobionts. In addition, chronic inflammatory diseases related to the GI tract, which include inflammatory bowel disease (IBD), can lead to malignancy susceptibility in the colon of both animals and humans. Recent studies suggest that dysbiosis of the oral microbiota can alter the microbial composition in relative abundance or diversity of the distal gut, leading to the progression of digestive carcinogenesis. The link between PD and specific GI disorders is also closely associated with the migration and colonization of periodontal pathogens and the subsequent microbe-reactive T cell induction within the intestines. In this review, an in-depth examination of this relationship and the accessibility of different mouse models of IBD and PD may shed light on the current dogma. As such, oral microbiota dysbiosis involving specific bacteria, including Fusobacterium nucleatum and Porphyromonas gingivalis, can ultimately lead to gut malignancies. Further understanding the precise mechanism(s) of the oral-gut microbial axis in PD, IBD, and colorectal cancer pathogenesis will be pivotal in diagnosis, prognosis, and future treatment.

Epidemiology and outcomes of primary sclerosing cholangitis with and without inflammatory bowel disease in an Australian cohort

BACKGROUND & AIMS

Epidemiological data on primary sclerosing cholangitis (PSC) outside the Northern hemisphere are limited. Similarly, the impact of inflammatory bowel disease (IBD) on PSC outcomes remains unclear. We aimed to study the epidemiology and outcomes of PSC patients with and without IBD in an Australian cohort.

METHODS

We retrospectively studied PSC patients attending two tertiary referral hospitals over 20 years. Diagnosis of PSC was made according to international guidelines by positive cholangiography and/or liver biopsy (for small duct PSC) with supporting clinical and laboratory evidence.

RESULTS

Of 208 PSC patients (61% male) were studied (2271patient-years follow-up). The median age of PSC diagnosis was similar for PSC-IBD and PSC-only patients (40 years vs 42 years, P = .35). All 33 deaths occurred in PSC-IBD patients while there were no deaths in PSC-only patients (21% vs 0%, P < .01). However, there were no significant differences in liver transplantation (PSC-only 25% vs PSC-IBD 31%, P = .45) and transplant-free survival between PSC-only and PSC-IBD patients (P = .43). On multivariate Cox regression, only elevated international normalized ratio (INR) was associated with a greater risk of death or liver transplant (HR 2.0, 95% CI 1.1-3.6, P = .02). Development of gastrointestinal malignancy was higher in the PSC-IBD group compared to PSC-only group (22% vs 2%, P < .01).

CONCLUSION

Australian PSC patients have similar characteristics compared to European and North American cohorts. IBD is a significant predictor of gastrointestinal malignancies. Deaths were more common in PSC-IBD but overall transplant-free survival remained similar in PSC-IBD and PSC-only groups. An elevated INR was an independent predictor of death or liver transplantation.

The impact of ulcerative colitis on the long-term outcome of patients with primary sclerosing cholangitis

BACKGROUND

The impact of ulcerative colitis (UC) on the outcome of primary sclerosing cholangitis (PSC) outcome remains unclear.

AIM

To investigate whether the presence of UC is associated with a worse clinical of associated PSC.

METHODS

A total of 222 patients with PSC (167 with UC and 55 without UC) seen and followed at a single centre from 1985 to 2011 were included. Clinical and demographic variables were obtained and patients were followed until the date of their last clinic visit.

RESULTS

The median age at presentation of PSC with associated UC was 38 vs. 47 years without UC (P < 0.001). At presentation, median serum bilirubin (2.1 vs. 4.5, P < 0.001) and the Mayo PSC Risk Score (0.95 vs. 1.69, P < 0.001) were lower in those with UC vs. those without UC. A total of 55 of 167 (32.9%) patients with PSC-UC developed colon neoplasia in contrast to 1 of the 55 (1.8%) patients with PSC. (P < 0.001) On proportional hazards analysis, UC (hazard ratio (HR) = 0.90 [95% confidence interval (CI): 0.60-1.34, P = 0.60] was not associated with death or orthotopic liver transplantation (OLT), when adjusting for gender, Mayo risk score and year of PSC diagnosis; whereas the revised Mayo risk score [HR = 5.08, 95% CI: (2.62-9.86), P < 0.001] was associated with a greater risk of OLT or death.

CONCLUSIONS

Primary sclerosing cholangitis often is recognised at an early stage in patients with concurrent ulcerative colitis; ulcerative colitis has no impact on long-term prognosis in terms of liver-related outcomes when adjusted for the severity of liver disease.

Inflammatory bowel disease is associated with poor outcomes of patients with primary sclerosing cholangitis

BACKGROUND & AIMS

Little is known about the exact etiology of primary sclerosing cholangitis (PSC); epidemiologic data are scarce. We performed a population-based epidemiologic study of PSC in Canterbury, New Zealand.

METHODS

By using multiple case-finding methods, we searched public and private adult and pediatric outpatient clinics, hospital discharge summaries, and radiology and pathology reports to identify all cases of PSC in the region. Cases were included if PSC was identified by endoscopic retrograde cholangiography, magnetic resonance cholangiography, or liver biopsy analysis (n = 79).

RESULTS

The incidence of PSC in 2008 was 1.6 per 100,000 persons (95% confidence interval [CI], 0.5-2.7). The point prevalence on December 31, 2008, was 11.7 per 100,000 persons (95% CI, 8.7-14.8). The mean and median ages at diagnosis were 50 years (95% CI, 46-53 years) and 49 years (range, 17-80 years), respectively. Patients who had inflammatory bowel disease (IBD) presented with PSC earlier than those without IBD (P = .003), were more likely to develop serious malignant complications (P = .017), and were more likely to require liver transplantation or die (P = .03).

CONCLUSIONS

In a population-based epidemiology study of PSC in Canterbury, New Zealand, we observed large differences between PSC patients with or without concurrent IBD in age at diagnosis, development of cancer, mortality, and requirement for liver transplantation. IBD therefore affects outcomes of patients with PSC, an important observation that requires further study.

Intracameral Toxicity of Bacterial Components Muramyl Dipeptide and Staurosporine: Ciliary Cyst Formation, Epithelial Cell Apoptosis and Necrosis

The uveitogenic bacterial cell wall component muramyl dipeptide (MDP) is apoptogenic in rabbit kidney cells. The purpose of this investigation was to assess the cytotoxic activity of MDP and staurosporine (STSP; induces cultured corneal and lens cells apoptosis) in rabbit ciliary body tissue. Anterior uveitis was determined by clinical symptoms and increased aqueous humor (AH) protein. Ciliary body tissue was assessed for histological changes, caspase-3 activity, dye uptake, distribution of immunoreactive caspase-3 and DNA ladders at 4 and 6 hours postinjection. Increases in caspase-3 activity, APOPercentage dye uptake, and localization of immunoreactive caspase-3 in ciliary epithelial cells were associated with ciliary cysts of detached nonpigmented epithelial (NPE) cells, as well as apoptotic and necrotic DNA ladders in ciliary body tissues from eyes injected with MDP and/or STSP. The results suggest that intracameral injection of the bacterial components MDP and STSP can induce acute endophthalmic changes in uveal tissue including formation of ciliary body, NPE and pigmented epithelial (PE) cell apoptosis, and ciliary body tissue necrosis.

Animal models for primary sclerosing cholangitis

Since the aetiopathogenesis of primary sclerosing cholangitis (PSC) in humans remains undefined, investigators have studied a variety of animal models to gain insights into immunopathogenetic mechanisms associated with obliterative fibrous cholangitis of intra- and extra-hepatic bile ducts. To date, no animal model has been developed that exhibits all of the attributes of PSC. Rodent models instigated by bacterial cell components or colitis are promising because they may help to explain the strong association between PSC and inflammatory bowel disease (IBD). Other models of direct injury to biliary epithelia, peribiliary vascular endothelia or portal venous endothelia indicate that inflammation, chemokines and cytokines can produce diffuse sclerosis of bile ducts. Models of toxic, infectious or intra-luminal injury of the biliary tract also exhibit focal biliary sclerosis mediated by inflammation and cytokines. The histopathology of several models suggests a sequence of events beginning with secretion of proinflammatory cytokines by activated hepatic macrophages followed by peribiliary infiltration with CD4 and CD8 T cells with a T helper 1 phenotype. These results strongly suggest co-ordinated, pathogenetic roles for both the innate and adaptive immune responses. However, the stimuli that initiate and perpetuate peribiliary fibrosis remain unknown. Interestingly, several models are also associated with the development of anti-neutrophil cytoplasmic antibodies that react in a perinuclear and cytoplasmic pattern similar to that observed in patients with ulcerative colitis and/or PSC. Finally, models of extra-hepatic biliary obstruction continue to provide important information about the pathogenesis of portal fibrosis and secondary biliary cirrhosis that occurs in PSC and other diseases with obstruction of bile flow. Future studies in either existing or new animal models should advance our understanding of the pathogenesis of PSC, the major prerequisite for the development of effective therapies.