Introduction: Cerebral vasoconstriction in the post-resuscitation phase worsens neurological outcome. Nitric oxide (NO) plays important roles mediating vasodilatation and anti-apoptotic protection. We therefore designed an Au-polymersomes/S-nitrosoglutathione (Au-PLGA/GSNO) nanoparticle that can be triggered by ultrasound (US) to release NO, and investigated its roles in mitigating cerebral vasoconstriction and neuronal apoptosis post-CPR. Hypothesis: Spatiotemporally controlled, US-triggered NO release by Au-PLGA/GSNO improves post-CPR cerebral perfusion and confers anti-apoptotic neuroprotection. Methods: Using an established rat model of asphyxia cardiac arrest and CPR, Au-PLGA/GSNO (7500 PPM, 0.4 ml) was infused with simultaneous US (1 MHz) stimulation at the brain 10 min after ROSC. Brain tissue perfusion was continuously recorded by OxyFLO probe and cerebral vasculature videoed by CytoCam. The blood was sampled 2 h post-CPR for measurement of nitrate/nitrite, and the brain harvested for measurement of casepase-3, endothelial NO synthase (eNOS) and protein kinase B (Akt). In a subgroup the brain was harvested at 24 h for TUNEL stain. Results: After CPR, marked cerebral vasoconstriction was noted on CytoCam while brain perfusion significantly reduced to ~0.5 folds that of baseline. After Au-PLGA/GSNO infusion and US stimulation, cerebral vasoconstriction was ameliorated and the brain perfusion significantly enhanced ( P < 0.05 vs. CPR control). The plasma NO indicated by nitrate/nitrite 2 h post-CPR was significantly increased ( P < 0.01) while cleaved caspase-3/caspase-3 of the brain markedly reduced ( P < 0.001). TUNEL stain of the hippocampus CA1 and CA3 regions were also remarkably abrogated, suggesting anti-apoptotic neuroprotection. Specifically, the phosphorylated (p)-eNOS/eNOS and p-Akt/Akt were also increased ( P < 0.01 and 0.001, respectively), indicating reciprocating activation of Akt-eNOS signaling upstream of NO. Conclusion: Spatiotemporally controlled US-triggered NO release by Au-PLGA/GSNO mitigates cerebral vasoconstriction, improves brain perfusion and confers anti-apoptotic neuroprotection post-CPR via reciprocating Akt-eNOS-NO signaling.

Herbal antioxidants have gained increasing attention in the prevention and treatment of ischaemic heart disease. Believed to have excellent free radical scavenging activity and relatively few adverse effects, they have been shown to be effective in attenuating the oxidation of low-density lipoprotein (LDL) cholesterol, diminishing the progression of atherosclerosis and mitigating the oxidative damage resulting from myocardial ischaemia/reperfusion injury. Scientific evidence from basic and clinical studies offer the solid base supporting their use as supplements and treatment in the clinical field. Furthermore, recent studies suggest some of these herbs may have potential use in the acute treatment of cardiovascular emergencies such as myocardial infarction and stroke. In this chapter, we introduce several herbal antioxidants currently popular and available over-the-counter, and discuss in detail their pharmacological properties and potential applications in the prevention and treatment of ischaemic heart disease.