Combined challenge of mice with Citrobacter rodentium and ionizing radiation promotes bacterial translocation

2-deoxy-D-glucose mitigates Citrobacter rodentium and dibenzazepine-induced gastrointestinal damage and colitis: novel implications of 2-DG polypharmacopea

PURPOSE

Citrobacter rodentium (CR) infection coupled with blocking Notch/Wnt signaling via γ-secretase inhibitor dibenzazepine (DBZ) disrupts the gastro-intestinal (GI) barrier and induces colitis, akin to ionizing radiation (IR)-induced GI-injury. We investigated the effects of 2-deoxy-D-glucose (2-DG) to ameliorate the CR-DBZ-induced GI damage.

MATERIALS AND METHODS

NIH:Swiss outbred mice were inoculated with 10⁹CFUs of CR orally. DBZ was administered intraperitoneally (10 μM/kg b.wt; for 10 days 2 days post-CR infection). Mice were fed with 0.4% 2-DG (w/v) daily in drinking water. For microbiota depletion, antibiotics (Abx), 1 g/l metronidazole, and 0.2 g/l ciprofloxacin were administered for 10 days in drinking water. Oxidative stress, survival assay, colonic crypt hyperplasia, Notch/Wnt downstream signaling, immunomodulation, and bacterial dysbiosis were measured.

RESULTS

We show that real-time visualization of reactive oxygen species (ROS) is similar during CR-induced colonic infection and IR-induced GI-damage. The histology revealed that dietary 2-DG mitigates CR + DBZ-induced colitis and improves survival compared with CR + DBZ alone. These changes were phenocopied in Abx-treated mice. Both 2-DG and Abx reduced dysbiosis, increased proliferation, inhibited pro-inflammatory response, and restored Hes-1 and β-catenin protein levels, in the crypts.

CONCLUSION

The energy disruptor 2-DG mitigates bacterial infection and its responsive hyperplasia/colitis, indicating its utility as a mitigator of infection/IR-induced GI-damage.

Recent advances in the management of radiation colitis

Radiation colitis, an insidious, progressive disease of increasing frequency, develops 6 mo to 5 years after regional radiotherapy for malignancy, owing to the deleterious effects of the latter on the colon and the small intestine. When dealing with radiation colitis and its complications, the most conservative modality should be employed because the areas of intestinal injury do not tend to heal. Acute radiation colitis is mostly self-limited, and usually, only supportive management is required. Chronic radiation colitis, a poorly predictable progressive disease, is considered as a precancerous lesion; radiation-associated malignancy has a tendency to be diagnosed at an advanced stage and to bear a dismal prognosis. Therefore, management of chronic radiation colitis remains a major challenge owing to the progressive evolution of the disease, including development of fibrosis, endarteritis, edema, fragility, perforation, partial obstruction, and cancer. Patients are commonly managed conservatively. Surgical intervention is difficult to perform because of the extension of fibrosis and alterations in the gut and mesentery, and should be reserved for intestinal obstruction, perforation, fistulas, and severe bleeding. Owing to the difficulty in managing the complications of acute and chronic radiation colitis, particular attention should be focused onto the prevention strategies. Uncovering the fibrosis mechanisms and the molecular events underlying radiation bowel disease could lead to the introduction of new therapeutic and/or preventive approaches. A variety of novel, mostly experimental, agents have been used mainly as a prophylaxis, and improvements have been made in radiotherapy delivery, including techniques to reduce the amount of exposed intestine in the radiation field, as a critical strategy for prevention.