Effect of hydrogen peroxide of bacterial origin on apoptosis and necrosis of gut mucosa epithelial cells as a possible pathomechanism of inflammatory bowel disease and cancer

A series of in vitro experiments was arranged to assess effects of different concentrations of H(2)O(2) contained in bacterial cultures on apoptosis and necrosis of HT-29 line cells representing human gut epithelium. On the basis of cytofluorimetric assays it was possible to demonstrate that supernatant of the Lactobacillus strain producing hydrogen peroxide (L. delbrueckii CU/22) was able to induce both apoptosis and necrosis in human epithelial culture cells HT-29. Both effects were more prominent than those visible under influence of supernatant of the non-H(2)O(2)-producing Lactobacillus strain or chemically pure H(2)O(2) at the same concentration used as a control. In the light of this study and also other reports on damaging effects of hydrogen peroxide and superoxide radicals of bacterial origin on colonic cells, commensal bacteria of the human gut producing H(2)O(2) may be involved in pathomechanisms of IBD by perpetuating the inflammatory reaction and increasing apoptosis and necrosis. There is a promise that probiotic preparations containing Lactobacillus bacteria will be successful as adjunct therapy of IBD and it is, therefore, postulated to make a very careful selection of the Lactobacillus strains as candidates for probiotics indicated to ameliorate the course of IBD, before starting clinical trials.

AM3 inhibits LPS-induced iNOS expression in mice

We have analyzed the effect of a patented glycoconjugate of natural origin, AM3 (commercially available under the name Inmunoferon) in the expression of iNOS induced by administration of LPS in mice. We have observed that oral treatment with the drug daily for 6 days reduced the levels of expression of iNOS induced by an intravenous pulse of LPS. This effect was significant in the lungs and kidneys, but it was much more marked in the liver. In addition, the levels of nitric oxide in serum were clearly decreased upon treatment with AM3. Together, these results suggest that AM3 modulates the nitric oxide response and points to a possible role for AM3 in the control of the inflammatory response.

NO-dependent phototoxicity of Roussin’s black salt against cancer cells

A metal-nitrosyl complex, Roussin's black salt (RBS), releases nitric oxide after illumination. Approximately 3.7 NO molecules were released from one RBS molecule. Both short- and long-term effects of photogenerated NO on the two neoplastic cell lines: human (SK-MEL188) and mouse (S91) have been investigated. Exogenous NO from RBS was toxic to cells in a dose-dependent manner. Apoptotic damage predominates in the response to the injury, as shown by TUNEL assay. NO and its short-lived metabolites, but not other RBS photoproducts, are responsible for cellular death. RBS in dark was toxic to cells at concentrations above 1 microM. This relatively high cytotoxicity of RBS in the dark prevents its application as a systemic anticancer agent in vivo, unless it is applied locally.