H2O2-Responsive Antioxidant Nanoparticle Attenuates Whole Body Ischemia/Reperfusion-Induced Multi-Organ Damages.

Mortality and morbidity after cardiac arrest remain high due to ischemia/reperfusion (I/R) injury causing multi-organ damages, even after successful return of spontaneous circulation. We previously generated H2O2-activatable antioxidant nanoparticles formulated with copolyoxalate containing vanillyl alcohol (PVAX) to prevent I/R injury. In this study, we examined whether PVAX could effectively reduce organ damages in a rat model of whole-body ischemia/reperfusion injury (WBIR). To induce a cardiac arrest, 70µl/100 g body weight of 1 mmol/l potassium chloride was administered via the jugular venous catheter. The animals in both the vehicle and PVAX-treated groups had similar baseline blood pressure. After 5.5 minutes of cardiac arrest, animals were resuscitated via intravenous epinephrine followed by chest compressions. PVAX or vehicle was injected after the spontaneous recovery of blood pressure was noted, followed by the same dose of second injection 10 minutes later. After 24 hours, multiple organs were harvested for pathological, biochemical, molecular analyses. No significant difference on the restoration of spontaneous circulation was observed between vehicle and PVAX groups. Analysis of organs harvested 24 hours post procedure showed that whole body I/R significantly increased reactive oxygen species (ROS) generation, inflammatory markers, and apoptosis in multiple organs (heart, brain, and kidney). PVAX treatment effectively blocked ROS generation, reduced the elevation of pro-inflammatory cytokines, and decreased apoptosis in these organs. Taken together, our results suggest that PVAX has potent protective effect against WBIR induced multi-organ injury, possibly by blocking ROS-mediated cell damage.

A Kidney-Targeted Nanoparticle to Augment Renal Lymphatic Density Decreases Blood Pressure in Hypertensive Mice.

Chronic interstitial inflammation and renal infiltration of activated immune cells play an integral role in hypertension. Lymphatics regulate inflammation through clearance of immune cells and excess interstitial fluid. Previously, we demonstrated increasing renal lymphangiogenesis prevents hypertension in mice. We hypothesized that targeted nanoparticle delivery of vascular endothelial growth factor-C (VEGF-C) to the kidney would induce renal lymphangiogenesis, lowering blood pressure in hypertensive mice. A kidney-targeting nanoparticle was loaded with a VEGF receptor-3-specific form of VEGF-C and injected into mice with angiotensin II-induced hypertension or LNAME-induced hypertension every 3 days. Nanoparticle-treated mice exhibited increased renal lymphatic vessel density and width compared to hypertensive mice injected with VEGF-C alone. Nanoparticle-treated mice exhibited decreased systolic blood pressure, decreased pro-inflammatory renal immune cells, and increased urinary fractional excretion of sodium. Our findings demonstrate that pharmacologically expanding renal lymphatics decreases blood pressure and is associated with favorable alterations in renal immune cells and increased sodium excretion.

Estimation of 222Rn release from the phosphogypsum board used in housing panels.

Phosphogypsum board is a popular construction material used for housing panels in Korea. Phosphogypsum often contains (226)Ra which decays into (222)Rn through an alpha transformation. (222)Rn emanated from the (226)Ra-bearing phosphogypsum board has drawn the public concern due to its potential radiological impacts to indoor occupants. The emanation rate of (222)Rn from the board is estimated in this paper. A mathematical model of the emanation rate of (222)Rn from the board is presented and validated through a series of experiments. The back diffusion effect due to accumulation of (222)Rn-laden air was incorporated in the model and found to have a strong impact on the (222)Rn emanation characteristics.