A novel rat model of inflammatory bowel disease developed using a device created with a 3D printer

Objective

Inflammatory bowel disease (IBD) is an intractable condition. Existing models of experimental IBD are limited by their inability to create consistent ulcers between animals. The aim of this study was to develop a novel model of experimental colitis with ulcers of reproducible size.

Design

We used a 3D printer to fabricate a novel device containing a small window (10 × 10 mm) that could be inserted rectally to facilitate the creation of a localized ulcer in the rat intestinal mucosa. The mucosa within the window of the device was exposed to 2,4,6-trinitrobenzene sulfonic acid (TNBS) to generate ulceration. We evaluated the effects of conventional drug therapies (mesalazine and prednisolone) and local transplantation of allogeneic adipose-derived mesenchymal stem cells (ASCs) on ulcer size (measured from photographic images using image analysis software) and degree of inflammation (assessed histologically).

Results

The novel method produced localized, circular or elliptical ulcers that were highly reproducible in terms of size and depth. The pathological characteristics of the lesions were similar to those reported previously for conventional models of TNBS-induced colitis that show greater variation in ulcer size. Ulcer area was significantly reduced by the administration of mesalazine or prednisolone as an enema or localized injection of ASCs.

Conclusion

The new model of TNBS-induced colitis, made with the aid of a device fabricated by 3D printing, generated ulcers that were reproducible in size. We anticipate that our new model of colitis will provide more reliable measures of treatment effects and prove useful in future studies of IBD therapies.

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Adipose-derived stem cells (ASCs) are being explored as a new treatment for IBD because they can downregulate inflammation and improve tissue repair.

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A new model of TNBS-induced colitis was developed using a custom-designed device fabricated by a 3D printer.

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The novel model of colitis generated ulcers that were highly reproducible in size.

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The size of the ulcer was reduced by mesalazine or prednisolone (administered as an enema) or by localized injection of ASCs.

Colon-specific prodrugs of 4-aminosalicylic acid for inflammatory bowel disease

Despite the advent of biological products, such as anti-tumor necrosis factor-α monoclonal antibodies (infliximab and adalimumab), for treatment of moderate to severe cases of inflammatory bowel disease (IBD), most patients depend upon aminosalicylates as the conventional treatment option. In recent years, the increased knowledge of complex pathophysiological processes underlying IBD has resulted in development of a number of newer pharmaceutical agents like low-molecular-weight heparin, omega-3 fatty acids, probiotics and innovative formulations such as high-dose, once-daily multi-matrix mesalamine, which are designed to minimize the inflammatory process through inhibition of different targets. Optimization of delivery of existing drugs to the colon using the prodrug approach is another attractive alternative that has been utilized and commercialized for 5-aminosalicylic acid (ASA) in the form of sulfasalazine, balsalazide, olsalazine and ipsalazine, but rarely for its positional isomer 4-ASA - a well-established antitubercular drug that is twice as potent as 5-ASA against IBD, and more specifically, ulcerative colitis. The present review focuses on the complete profile of 4-ASA and its advantages over 5-ASA and colon-targeting prodrugs reported so far for the management of IBD. The review also emphasizes the need for reappraisal of this promising but unexplored entity as a potential treatment option for IBD.

Serum protein oxidation by diesel exhaust particles: effects on oxidative stress and inflammatory response in vitro

Considerable evidence shows a key role for protein modification in the adverse effects of chemicals; however, the interaction of diesel exhaust particles (DEP) with proteins and the resulting biological activity remains unclear. DEP and carbon black (CB) suspensions with and without bovine serum albumin (BSA) were used to elucidate the biological effects of air pollutants. The DEP and CB samples were then divided into suspensions and supernatants. Two important goals of the interaction of DEP with BSA were as follows: (1) understanding BSA modification by particles and (2) investigating the effects of particles bound with BSA and the corresponding supernatants on cellular oxidative stress and inflammation. We observed significant free amino groups production was caused by DEP. Using liquid chromatography-mass spectrometry (LC-MS), we observed that BSA was significantly oxidised by DEP in the supernatants and that the peptides ETYGDMADCCEK, MPCTEDYLSLILNR and TVMENFVAFVDK, derived BSA-DEP conjugates, were also oxidised. In A549 cells, DEP-BSA suspensions and the corresponding supernatants reduced 8-hydroxy-2'-deoxyguanosine (8-OHdG) production and increased interleukin-6 (IL-6) levels when compared to DEP solutions without BSA. Our findings suggest that oxidatively modified forms of BSA caused by DEP could lead to oxidative stress and the activation of inflammation.

Sensory neuro-immune interactions differ between irritable bowel syndrome subtypes

OBJECTIVE

The gut is a major site of contact between immune and sensory systems and evidence suggests that patients with irritable bowel syndrome (IBS) have immune dysfunction. Here we show how this dysfunction differs between major IBS subgroups and how immunocytes communicate with sensory nerves.

DESIGN

Peripheral blood mononuclear cell supernatants from 20 diarrhoea predominant IBS (D-IBS) patients, 15 constipation predominant IBS (C-IBS) patients and 36 healthy subjects were applied to mouse colonic sensory nerves and effects on mechanosensitivity assessed. Cytokine/chemokine concentration in the supernatants was assessed by proteomic analysis and correlated with abdominal symptoms, and expression of cytokine receptors evaluated in colonic dorsal root ganglia neurons. We then determined the effects of specific cytokines on colonic afferents.

RESULTS

D-IBS supernatants caused mechanical hypersensitivity of mouse colonic afferent endings, which was reduced by infliximab. C-IBS supernatants did not, but occasionally elevated basal discharge. Supernatants of healthy subjects inhibited afferent mechanosensitivity via an opioidergic mechanism. Several cytokines were elevated in IBS supernatants, and levels correlated with pain frequency and intensity in patients. Visceral afferents expressed receptors for four cytokines: IL-1β, IL-6, IL-10 and TNF-α. TNF-α most effectively caused mechanical hypersensitivity which was blocked by a transient receptor potential channel TRPA1 antagonist. IL-1β elevated basal firing, and this was lost after tetrodotoxin blockade of sodium channels.

CONCLUSIONS

Distinct patterns of immune dysfunction and interaction with sensory pathways occur in different patient groups and through different intracellular pathways. Our results indicate IBS patient subgroups would benefit from selective targeting of the immune system.