Uso de células-tronco mesenquimais no tratamento da sepse e da lesão pulmonar aguda

Abstract

Mesenchymal stem cells (MSC) were first identified by Friedenstein and Petrakova (1966), who isolated these progenitor cells from rat bone marrow and found that these cells are able to differentiate into connective tissue lineage including bone, adipose tissue, cartilage and muscle. MSCs have emerged in recent years as therapeutic tools based on four important features: differentiation potential, capacity to modulate immune responses, pro-angiogenic and repair promoting capacities, and low immunogenicity, the latter feature may allow allogeneic treatments. Based on their immunomodulatory properties and paracrine effects through trophic factors with anti-fibrotic, anti-apoptotic or pro-angiogenic properties, MSCs are considered a promising instrument for cell therapy, in particular for inflammatory diseases. MSCs regulate the function of a broad range of immune cells, and are activated by inflammatory mediators released from activated immune cells. The mechanisms involved in the immunoregulatory activity of MSCs are still under investigation. Therefore, MSCs become a potential treatment alternative for sepsis and for acute lung infection, which may lead to the interruption of the sequence in the pathogenesis and cause mortality reduction of both pathologies. The principal objective of this study was to evaluate the therapeutic and immunomodulatory effect of MSCs in the treatment of sepsis and acute lung injury and search for their possible mechanisms of action. Our results demonstrated for the first time that the reduction of inflammation in sepsis caused by treatment with MSCs is directly involved in the inhibition of the pathway of mitogen-activated proteins (MAPKs) and that MSCs were unable to modulate the expression of toll-like receptors. During acute lung injury (ALI), the immunomodulation caused by the treatment and the decrease of the oxidative stress that consequently led to a decrease in the formation of extracellular neutrophil network (NETs), leading to an increase in the survival of animals with LPA. The promising results obtained in these studies are encouraging and suggest that MSCs might be a therapeutic option to treat sepsis and acute lung infection in patients in the future.