Development of an anti-inflammatory fermented milk product using IL-10 producing Lactococcus lactis

DEL CARMEN, S.; DE MORENO DE LEBLANC, A.; LEBLANC, J. G.

San Miguel de Tucuman

Congreso; VII Congreso Argentino de Microbiología General (SAMIGE); 2011

Inflammatory bowel diseases (IBD) have become one of the major gastroenterologic problems in the Western world. Although the exact etiology of these disorders has not yet been elucidated, it is well known that a cytokine imbalance is associated to these pathologies. Interleukin-10 (IL-10), the most important anti-inflammatory cytokine, is essential in preventing IBD. Oral treatment with IL-10 is difficult because of its sensitivity to the harsh conditions in the gastrointestinal tract (GIT), and systemic treatments are related to undesirable side effects. On the other hand, intragastric administration of genetically modified Lactococcus (L.) lactis producing IL-10 in situ in the intestine was shown to be effective in the treatment of IBD; however its use is hindered by the sensitivity of these bacteria to freeze-drying and their poor survival in the GIT. The aim of this study was to develop a fermented milk product using a strain of L. lactis that produces IL-10 under the control of the xylose inducible expression system (XIES) and evaluate its anti-inflammatory effect using a murine colitis model. Two genetically engineered strains of L. lactis NCDO2118 (hereafter referred as the wild-type (Wt) strain) harboring the XIES to target rodent IL-10 to the cytoplasm (Cyt strain) or to the extracellular medium (Sec strain) were used. Reconstituted sterile nonfat milk containing 1% xylose was inoculated with one of these strains (Wt, Cyt or Sec) at a concentration of 1% (v/v) and incubated statically for 16 h at 30°C. IL-10 concentration in the fermented milks was determined by ELISA. The anti-inflammatory potential of the fermented milk products was evaluated using a chemically induced trinitrobenze sulfonic acid (TNBS) colitis murine model. Animals inoculated with TNBS were sub-divided into 4 experimental groups: 1) Inflammation group (TNBS group) without special feeding; 2) TNBS-Wt group, where mice received milk fermented with the Wt strain; 3) TNBS-Cyt group, where mice received milk fermented with the Cyt strain and 4) TNBS-Sec group, where mice received milk fermented with the Sec strain. Microbial translocation to liver, macroscopic and histological damage of the intestines and cytokine production profiles in fluids and tissues were evaluated in each experimental group. Mice that received milks fermented by L. lactis strains producing IL-10 in the cytoplasm (Cyt strain) or secreted to the product (Sec strain) possessed anti-inflammatory properties as shown by lower damage scores in their large intestines, decreased IFN-gamma; levels in their intestinal fluids and lower translocation to liver, compared to mice receiving milk fermented by the wild-type (Wt) strain or those not receiving any treatment. The use of fermented milks as a new form of administration of IL-10 producing L. lactis was effective in the prevention of IBD in a murine model. These results could lead to the development of novel functional or therapeutical foods.