Erythrocyte Antioxidant Enzyme Activities and Lipid Peroxidation in Patients with Types IIb and IV Hyperlipoproteinemias

Baroreflex sensitivity and oxidative stress in the LDL receptor knockout mice

This study aims at observing the effect of low-density lipoprotein (LDL) receptor deficiency in cholesterol blood levels, baroreflex sensitivity (BRS), nitric oxide (NO) bioavailability, and oxidative stress. The lack of LDL receptors in mice significantly increased the cholesterol blood levels (179+/-35 vs. 109+/-13mg/dL) in the knockout (KO) mice compared to control. There was no difference in basal mean arterial pressure and heart rate between the groups. However, in KO mice the BRS was significantly attenuated and the antioxidant enzyme activities, measured in erythrocytes and heart, were significantly decreased. On the other hand, the oxidative damage measured by chemiluminescence and carbonyls was increased, while total plasma nitrate levels were lower in KO mice, indicating a decrease in NO availability. In conclusion, these results indicate that the lack of LDL receptor increased cholesterol blood levels, induced oxidative stress and decreased BRS.

Arenicola marina extracellular hemoglobin: a new promising blood substitute

The need to develop a blood substitute is now urgent because of the increasing concern over Europe's BSE outbreak and the worldwide HIV/AIDS epidemic, which have cut blood supplies. Extracellular soluble hemoglobin has long been studied for its possible use as a safe and effective alternative to blood transfusion, but this has met with little success. Clinical trials have revealed undesirable side effects-oxidative damage and vasoconstriction-that hamper the application of cell-free hemoglobin as a blood substitute. We have addressed these problems and have found a new promising extracellular blood substitute: the natural giant extracellular polymeric hemoglobin of the polychaete annelid Arenicola marina. Here we show that it is less likely to cause immunogenic response; its functional and structural properties should prevent the side effects often associated with the administration of extracellular hemoglobin. Moreover, its intrinsic properties are of interest for other therapeutic applications often associated with hemorrhagic shock (ischemia reperfusion, treatment of septic shock and for organ preservation prior to transplantation). Moreover, using natural hemoglobin is particularly useful since recombinant DNA techniques could be used to express the protein in large quantities.