The effect of peroxides on the vascular endothelium of isolated pig aorta in vitro

Controlled oxygen delivery to power tissue regeneration

Oxygen plays a crucial role in human embryogenesis, homeostasis, and tissue regeneration. Emerging engineered regenerative solutions call for novel oxygen delivery systems. To become a reality, these systems must consider physiological processes, oxygen release mechanisms and the target application. In this review, we explore the biological relevance of oxygen at both a cellular and tissue level, and the importance of its controlled delivery via engineered biomaterials and devices. Recent advances and upcoming trends in the field are also discussed with a focus on tissue-engineered constructs that could meet metabolic demands to facilitate regeneration.

Halothane does not protect against vascular injury in isolated cerebral and mesenteric arteries

PURPOSE

This study was designed to examine regional differences in the vascular injury induced by hydrogen peroxide (H2O2) and to determine its modulation by halothane in canine basilar and mesenteric arteries.

METHODS

Rings of canine basilar and mesenteric arteries with intact endothelium were mounted in Krebs bicarbonate solution for isometric tension recording. The relaxation responses to substance P (10(-8) M) and sodium nitroprusside (SNP; 10(-8) to 10(-5) M) were examined before and after exposure to H2O2 (1 mM) for eight minutes in the presence or absence of halothane (2%), to evaluate the effects of oxidative injury on the endothelium-dependent and -independent relaxation. The contractile responses to KCl (30 mM) and prostaglandin (PG) F(2alpha) (3 x 10(-6) M) were also compared in rings with and without exposure to H2O2.

RESULTS

After exposure to H2O2 the relaxant responses to substance P were significantly inhibited in basilar arteries (P < 0.01), but not in mesenteric arteries. Exposure to H2O2 also attenuated SNP-induced relaxation in basilar (P < 0.05), but not in mesenteric arteries. The attenuation of the contractile responses to KCl and PGF(2alpha) after H2O2 exposure was observed only in basilar arteries (P < 0.01). Simultaneous exposure to halothane did not affect the attenuation of these relaxant and contractile responses. Scanning electron microscopy revealed that H2O2 resulted in marked disruption of the endothelial layer in basilar arteries, compared to almost no morphological changes in mesenteric arteries.

CONCLUSION

These results indicate that the endothelium and vascular smooth muscle of the basilar artery are more susceptible to oxidative stress than those of the mesenteric artery. Halothane, at clinically relevant concentrations, exerts no significant influence on this vascular injury.

Peroxide treatment changes activity of non specific esterase in vascular endothelium of isolated pig aorta in vitro

The effect of hydrogen peroxide on certain enzymes contained in endothelial cells was investigated in vitro. Specifically in this study the influence of hydrogen peroxide on the non-specific esterase activity in endothelial cells of the perfused pig aorta was examined. We perfused an isolated segment of the pig aorta for 10 h and added 5, 10, 12, 15 ml 10% hydrogen peroxide to 100 ml perfused medium. In unperfused pig aorta 99.34% of the endothelial cells reacted positive. After 10 h of perfusion without hydrogen peroxide administration 93.25% endothelial cells still showed positive enzyme reactivity. In presence of hydrogen peroxide in the perfusion medium the activity of non-specific esterase was progressively inhibited, finally causing complete inactivation.