Peroxynitrites and matrix metalloproteinases in the term placenta from type 2 diabetic patients

CAPOBIANCO EVANGELINA , SOSA MARÍA , BASUALDO NATALIA , DI MARCO INGRID, FAINGOLD CRISTINA , JAWERBAUM ALICIA

Santiago de Chile

Congreso; International Federation of Placenta Associations IFPA 2010; 2010

IFPA

Introduction: Type 1 pregestational diabetes leads to a pro-inflammatory intrauterine environment, characterized by increased reactive oxygen species (ROS), nitric oxide (NO) overproduction and matrix metalloproteinases (MMP) overactivity. The objective of this work was to address oxidative and nitrative stress in the placenta from Type 2 pregestational diabetes, and whether peroxynitrites regulate the activity of MMP-2 and MMP-9 in the placenta. Methods: Term placental villous tissues from healthy and pregestational type 2 diabetic patients, were isolated and frozen (-80¨¬C) for further determination of TBARS (an index of lipid peroxidation), nitrates/nitrites (an index of NO production), concentrations of nitrated proteins (enzimoinmunoanalysis and Western Blot). Placental explants were incubated a) in the presence or absence of FeTPPs (a peroxynitrite catalyst) for further determination of nitrates/nitrites and TBARS, and b) in the presence or absence of peroxynitrites (10-100 microM) for further determination of MMPs activity by zymography. Results: The placenta from Type 2 diabetic patients showed increased nitrates/nitrites (p<0.01), increased TBARs (p<0.01) and increased concentrations of nitrated proteins (p<0.001). The addition of a peroxynitrite catalyst reduced nitrates/nitrites (p<0.05) and TBARs (p<0.05) concentrations in the diabetic placenta, while no changes were observed in the control tissues. The addition of peroxynitrites increased the activation of both MMP-2 (p<0.05) and MMP-9 (p<0.05) proenzymes in the control tissues, while no changes were observed in the diabetic tissues. Conclusions: Markers of both oxidative and nitrative stress are found in term placentas form type 2 diabetic patients and can be related to MMPs overactivity. In the human placenta, peroxynitrites can exert damage, in part due to its capacity to induce lipid peroxidation and MMPs overactivity.