[Characterization of hemodynamic ex vivo model to study endothelial activation by TNF-α in prefunded human veins]. / Caracterización de un modelo hemodinámico ex vivo para el estudio de la activación endotelial por el factor de necrosis tumoral α (TNF-α) en venas humanas perfundidas.

Inflammation is recognized as part of the etiology of numerous diseases. The interaction among cells of the immunological system with local cells and molecules, such as cytokines and chemokines, allows cellular activation and response amplification. The importance of several physicochemical factors like frictional force, vascular flow, shear stress, and pressure is now recognized because they are known to modulate genetic expression and endothelial activation; however, there are very few studies that recreate such cellular microenvironments. Hence, it is of paramount importance to develop new models that will mimic physiological conditions. Our aim was to improve a human vein ex vivo model that would allow endothelial activation in flow conditions, to study the molecular components during adhesion, taking into consideration physicochemical parameters such as flow and shear stress. Endothelial umbilical human vein was used and activated with TNF-a in order to determine U937 monocytic cells adhesion, as well as cytokines secretion and ICAM-1 expression. This model will allow leukocyte adhesion studies, using different inflammatory stimulus, along with the signaling pathways involved in several pathologies.

[Hormesis: What doesn't kill you makes you stronger]. / Hormesis: lo que no mata, fortalece.

Living organisms have always had to cope with harsh environmental conditions and in order to survive, they have developed complex mechanisms to deal with them. These responses have been assembled in a concept called hormesis, which has been identified as an evolutionarily conserved process in which a low dose of a stressful stimulus activates an adaptive response that increases the resistance of the cell or organism to higher stress level. The main hormetic agents identified so far are irradiation, heat, heavy metals, antibiotics, ethanol, pro-oxidants, exercise and food restriction. The hormetic response involves the expression of genes that encode cytoprotective proteins such as chaperones like heat-shock proteins, antioxidant enzymes and growth factors. In this review we will discuss the hormetic response mainly during an oxidative challenge, and its relationship with senescence and aging, and some related diseases such as diabetes and neurodegeneration.

Acetaldehyde-induced mitochondrial dysfunction sensitizes hepatocytes to oxidative damage.

Acetaldehyde (Ac), the main metabolite of ethanol oxidation, is a very reactive compound involved in alcohol-induced liver damage. In the present work, we studied the effect of Ac in mitochondria functionality. Mitochondria from Wistar rats were isolated and treated with Ac. Ac decreased respiratory control by 50% which was associated with a decrease in adenosine triphosphate content (28.5%). These results suggested that Ac could be inducing changes in cell redox status. We determined protein oxidation, superoxide dismutase (SOD) activity, and glutathione ratio, indicating that Ac induced an enhanced oxidation of proteins and a decrease in SOD activity (90%) and glutathione/oxidized GSH ratio (36%). The data suggested that Ac-induced oxidative stress mediated by mitochondria dysfunction can lead to cell sensitization and to a second oxidative challenge. We pretreated hepatocytes with Ac followed by treatment with antimycin A, and this experiment revealed a noticeable decrease in cell viability, determined by neutral red assay, in comparison with cells treated with Ac alone. Our data demonstrate that Ac impairs mitochondria functionality generating oxidative stress that sensitizes cells to a second damaging signal contributing to the development of alcoholic liver disease.

Assessment of micronucleus and oxidative stress in peripheral blood from malnourished children.

INTRODUCTION: malnutrition is one of the most common health problems among children in underdeveloped countries, including Mexico. Previous studies have indicated increased genetic damage in malnourished humans and animal models, but the essential mechanisms remain unclear. In the present study, we assessed the effects of malnutrition on the frequency of micronucleus (MN) in reticulocytes (RET) from the peripheral blood of well-nourished uninfected (WN), well-nourished infected (WNI), moderately malnourished infected (UNM) and severely malnourished infected (UNS) children. Moreover, lipid peroxidation and the antioxidant status were evaluated to investigate the role of oxidative processes in malnutrition-associated genotoxicity. METHODS: the antioxidant status of the study population was determined by measuring superoxide dismutase (SOD) in the red blood cells and glutathione peroxidase (GPX) in whole blood. RESULTS: the UNS and UNM groups have increased percentages of MN-RET compared to the WNI group. Moreover, the data showed a significant increase in lipid peroxidation and a decrease in erythrocyte SOD activity and GPX activity in the malnourished group compared to the well-nourished infected children. CONCLUSION: the data suggest that the antioxidant system was impaired in the cells of malnourished children and that oxidative stress causes a significant increase in DNA damage, as evaluated by the MN-RET frequency.