Therapeutic use of an antibiotic-resistant Bifidobacterium preparation in men exposed to high-dose gamma-irradiation

Animal Care in Radiation Medical Countermeasures Studies

Animal models are necessary to demonstrate the efficacy of medical countermeasures (MCM) to mitigate/treat acute radiation syndrome and the delayed effects of acute radiation exposure and develop biodosimetry signatures for use in triage and to guide medical management. The use of animal models in radiation research allows for the simulation of the biological effects of exposure in humans. Robust and well-controlled animal studies provide a platform to address basic mechanistic and safety questions that cannot be conducted in humans. The U.S. Department of Health and Human Services has tasked the National Institute of Allergy and Infectious Diseases (NIAID) with identifying and funding early- through advanced-stage MCM development for radiation-induced injuries; and advancement of biodosimetry platforms and exploration of biomarkers for triage, definitive dose, and predictive purposes. Some of these NIAID-funded projects may transition to the Biomedical Advanced Research and Development Authority (BARDA), a component of the Office of the Assistant Secretary for Preparedness and Response in the U.S. Department of Health and Human Services, which is tasked with the advanced development of MCMs to include pharmacokinetic, exposure, and safety assessments in humans. Guided by the U.S. Food and Drug Administration's (FDA) Animal Rule, both NIAID and BARDA work closely with researchers to advance product and device development, setting them on a course for eventual licensure/approval/clearance of their approaches by the FDA. In August 2020, NIAID partnered with BARDA to conduct a workshop to discuss currently accepted animal care protocols and examine aspects of animal models that can influence outcomes of studies to explore MCM efficacy for potential harmonization. This report provides an overview of the two-day workshop, which includes a series of special topic presentations followed by panel discussions with subject-matter experts from academia, industry partners, and select governmental agencies.

MMP7 Modulation by Short- and Long-term Radiotherapy in Patients with Rectal Cancer

BACKGROUND/AIM

Matrix metalloproteinase 7 (MMP7) expression is highly associated with colorectal cancer and modulates tumour growth and invasion. Radiation injury induces inflammation with increases in MMP7 and in transforming growth factor beta (TGFβ). The aim of this study was to investigate the effect on MMP7 and TGFβ. expression in patients with rectal cancer undergoing different regimens of neoadjuvant radiotherapy (RT).

PATIENTS AND METHODS

We studied 53 patients in three RT treatment groups receiving RT of 25 Gy, long-term RT 50 Gy and controls receiving no RT. Three biopsies were obtained from each patient during the treatments: before RT, after RT and after surgery. Tissue samples were formalin fixed, paraffin embedded and tissue microarrays were constructed and stained for MMP7 and TGFβ. Mann-Whitney U-tests and Wilcoxon Z-tests were used to determine differences between patients before and after RT, and after surgery, as well as between the RT groups.

RESULTS

In all three patient groups, increases of MMP7 and TGFβ expression were observed after surgery. MMP7 expression was significantly increased in patients receiving short-term RT but TGFβ expression was not affected by RT.

CONCLUSION

50 Gy Irradiation of rectal cancer gives less tumour activation of MMP7, whilst it is up-regulated by 25 Gy and surgery regardless of RT.

Matrilysin expression related to radiation and microflora changes in murine bowel

BACKGROUND

Matrilysin (MMP-7) elevation after radiotherapy is shown in humans. Matrilysin regulates certain cytokines and the production of bactericidal proteins when the mucosa is exposed to bacterial antigens. We investigate the effect of irradiation on matrilysin and microflora in murine bowel, after modulation with antibiotics.

METHODS

Animals were divided into two different groups a radiation group (72 animals) and sham radiation group (36 animals). Animals were divided into smaller groups of six according to radiation dose (19 or 38 Gy or sham). Seven days before radiotherapy ampicillin 500 mg/kg/d was administered intramuscularly, in the antibiotic groups. An exteriorized segment of ileum was subjected to single high dose radiation (19 or 38 Gy). Samples were collected 2, 24, and 48 h and analyzed for microflora, MIP-2, TGF-β, and MMP-7.

RESULTS

The combination of antibiotics and irradiation leads to an early significant reduction of bacteria, down-regulates MIP-2, up-regulates TGF-β and elevation of MMP-7 to levels achieved by antibiotics or irradiation alone. Lactobacilli were reduced to non-existent levels after antibiotics.

CONCLUSIONS

Pretreatment with Ampicillin before irradiation and laparotomy in a murine model leads to Matrilysin over-expression as achieved by radiotherapy alone. Microfloral regulation does not affect MMP-7 stimulation after surgical or radiological trauma. Radiotherapy overrides the effect of antibiotics leading to an up-regulation of MMP-7, TGF-β and MIP-2 expression between 24 h and 48 h.

Probiotics used in human studies

GOAL

To investigate the literature from 1980 to 2004 for the types of studies and organisms used as probiotics in human studies and diseases.

METHODS

PubMed search for probiotic organisms used in studies from 1980 to August 2004. The data from those papers were evaluated for organisms used, dose, vehicle, frequency, and investigator's report of positive or negative results.

RESULTS

A total of 185 manuscripts were identified. Investigators reported results of both single and multiple organisms in the same manuscript. A single organism was used in 125 reports, and multiple organisms, ranging from 2 to 9, were used in 60 reports. Positive results were reported in 239 clinical situations and negative results reported in 49 in a total of 288 clinical conclusions drawn by the respective investigators. The studies are tabulated in this review.

CONCLUSION

There is a large literature available in credible journals that report benefit of probiotic administration using a wide range of doses, organisms, and clinical situations. Most of the studies are simple reports of a clinical situation and require additional evaluation.

Purification and characterization of a novel protein produced by Bifidobacterium longum SBT2928 that inhibits the binding of enterotoxigenic Escherichia coli Pb176 (CFA/II) to gangliotetraosylceramide

A novel protein (BIF) which shows inhibitory activity on the binding of enterotoxigenic Escherichia coli Pb176 (ETEC with colonization factor antigen (CFA) II, which consists of coli surface-associated antigens CS1 and CS3) to gangliotetraosylceramide (asialo GM1 or GA1) was isolated from the culture supernatant fluid of Bifidobacterium longum SBT2928 (BL2928) at its stationary phase. The homogeneity of the final preparation of BIF was demonstrated by SDS-PAGE, polyacrylamide gel electrofocusing and N-terminal amino acid sequencing. The BIF was characterized as (i) a protein with an M(r) of approximately 104 kDa when chromatographed on a gel filtration column, and 52 kDa when separated on SDS-PAGE, and (ii) having an isoelectric point of 5.9. No change in size was produced by thiol reduction. These results suggest that BIF is a homodimer consisting of identical 52 kDa monomers. The purified BIF at the concentration of 25 micrograms protein ml-1 caused a 50% reduction in binding of the ETEC strain to GA1.

Protective effect of bifidus milk on the experimental infection with Salmonella enteritidis subsp. typhimurium in conventional and gnotobiotic mice

The ability of Bifidobacterium bifidum from a commercial bifidus milk to antagonize Salmonella enteritidis subsp. typhimurium in vivo, and to reduce the pathological consequences for the host, was determined using conventional and gnotobiotic mice. Conventional animals received daily, by gavage, 0.1 ml bifidus milk containing about 10(9) cfu B. bifidum and germ-free animals received a single 0.1 ml dose. The conventional and gnotobiotic groups were challenged orally with 10(2) cfu of the pathogenic bacteria 5 and/or 10 d after the beginning of treatment. Control groups were treated with milk. Bifidus milk protected both animal models against the challenge with the pathogenic bacteria, as demonstrated by survival and histopathological data. However, to obtain the protective effect in gnotobiotic animals, the treatment had to be initiated 10 d before the challenge. In experimental and control gnotobiotic mice, Salm. enteritidis subsp. typhimurium became similarly established at levels ranging from 10(8) to 10(9) viable cells g-1 of faeces and remained at these high levels until the animals died or were sacrificed. It was concluded that the protection against Salm. enteritidis subsp. typhimurium observed in conventional and gnotobiotic mice treated with bifidus milk was not due to the reduction of the intestinal populations of the pathogenic bacteria.