Anti-inflammatory effect of multistrain probiotic formulation (L. rhamnosus, B. lactis, and B. longum)

OBJECTIVE

In recent years, a great number of studies have been directed toward the evaluation of gastrointestinal microbiota modulation through the introduction of beneficial microorganisms, also known as probiotics. Many studies have highlighted how this category of bacteria is very important for the good development, functioning, and maintenance of our immune system. There is a delicate balance between the immune system, located under the gut epithelial barrier, and the microbiota, but many factors can induce a disequilibrium that leads to an inflammatory state and dysbiosis. The aim of this work is to verify the anti-inflammatory effects of a probiotic formulation of Lactobacillus rhamnosus, Bifidobacterium lactis, and Bifidobacterium longum (Serobioma).

METHODS

To mimic the natural host compartmentalization between probiotics and immune cells through the intestinal epithelial barrier in vitro, the transwell model was used. We focused on a particular subset of immune cells that play a key role in the mucosal immune system. The immunomodulatory effects of probiotic formulation were investigated in the human macrophage cell line THP1 and macrophages derived from ex vivo human peripheral blood mononuclear cells.

RESULTS

Probiotic formulation induced a significant increase in anti-inflammatory cytokine interleukin-10 (IL-10) production and was able to decrease the secretion of the major proinflammatory cytokines IL-1β and IL-6 by 70% and 80%, respectively. Finally, for the first time, the ability of probiotic formulation to favor the macrophage M2 phenotype has been identified.

CONCLUSION

The transwell model is an intriguing toll approach to studying the human epithelial barrier.

Interleukin-1β induces an inflammatory response and the breakdown of the endothelial cell layer in an improved human THBMEC-based in vitro blood-brain barrier model

BACKGROUND

The blood-brain barrier is necessary to provide an optimal environment for cerebral function. It consists of endothelial cells that interact through interendothelial tight junctions and form a barrier with low permeability. Therefore, the infiltration of lymphocytes into the central nervous system is limited. Pathological conditions, such as chronic-inflammatory diseases and viral infections, induce a breakdown in the blood-brain barrier, which facilitates the accumulation of immune cells in the brain.

NEW METHOD

Using the endothelial cell line "transfected human brain microvascular endothelial cells", we established an improved in vitro blood-brain barrier model. Using interleukin-1β, we refined this model into an inflammatory blood-brain barrier model.

RESULTS

The model is characterised by a transendothelial electrical resistance of 250 Ohm cm(2) and a permeability coefficient of 1×10(-6) cm/s for sodium fluorescein. IL-1β induces a strong inflammatory response, resulting in the increased expression of the adhesion molecule ICAM-1 and the pro-inflammatory cytokines IL-6, IL-8, and TNFα. Furthermore, the transendothelial electrical resistance decreased and the paracellular permeability increased in the presence of IL-1β. Additionally, the expression of the tight junction protein ZO-1 was reduced. As a consequence, an increased number of leukocytes were able to cross the cell layer.

COMPARISON WITH EXISTING METHODS

The model presented here exhibits improved characteristics with regards to TEER and permeability. The influence of IL-1β has not been described before in this model system.

CONCLUSION

The inflammatory in vitro blood-brain barrier model provides a useful tool for studying inflammatory processes at the blood-brain barrier, especially processes provoked by IL-1β.