INTRODUCCIÓN: REVISIÓN CRITICA DEL PROBLEMA

Abstract
ANEXOS
Background: Diabetes vascular complications could be mediated by non-
enzymatic glycation of proteins, but the mechanisms are far from being clear. Our
objective was to identify the regulation pathways implicated in the glycated human
serum albumin (gHSA)-enhanced ROS production in human umbilical vein
endothelial cells (HUVEC).
Methods: The implication in the gHSA-enhanced extracellular reactive oxygen
species (ROS) production of nuclear factor kappa-light-chain-enhancer of
activated B cells (NF-κB) and activator protein-1 (AP-1), and of two
phosphorilation cascades mediated by phosphatidylinositol 3-kinase (PI3K) and
mitogen-activated protein kinase kinase 1/2 (MEK 1/2) were analyzed. Genetic
expression levels were measured by RT-qPCR and extracellular ROS production
by the cytochrome c reduction method.
Results: NF-κB activation by gHSA was observed and NF-κB inhibition reversed
the gHSA enhanced NOX4 expression and tended to decrease gHSA-induced
ROS production. The inhibition of AP-1 with SP600125 induced a rise of NOX4
and P22PHOX subunits expression and a down-regulation of endothelial nitric
oxide synthase (eNOS). However, SP600125 enhanced ROS production in the
presence of human serum albumin, but not with gHSA. gHSA also produced
eNOS uncoupling, which could explain these results. The phosphorilation
pathways mediated by PI3K or MEK 1/2 did not seem to be involved in gHSA-
induced ROS production.
Conclusions: All together suggests that gHSA-enhanced ROS production in
HUVEC was the result of: 1) up-regulation of NOX4 NADPH oxidase subunit by
NF-κB activation and 2) eNOS uncoupling. Our results also showed that AP-1
activity is an important factor for the expression of NADPH oxidase and eNOS in
HUVEC.
KEYWORDS: Amadori products; glycated human serum albumin; reactive oxygen
species; endothelial dysfunction; NF-κB.
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