Genetic deletion of TRAIL or antibody blockade prevents the development of pulmonary arterial hypertension and can reverse vascular remodeling in established disease.

Background-Restenosis after percutaneous coronary intervention remains a serious clinical problem. Progress in local gene therapy to prevent restenosis has been hindered by concerns over the safety and efficacy of viral vectors and the limited efficiency of nonviral techniques. This study investigates the use of adjunctive ultrasound to enhance nonviral gene delivery. Methods and Results-Cultured porcine vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) were transfected with naked or liposome-complexed luciferase reporter plasmid for 3 hours. Ultrasound exposure (USE) for 60 seconds at 1 MHz, 0.4 W/cm 2 , 30 minutes into this transfection period enhanced luciferase activity 48 hours later by 7.5-fold and 2.4-fold, respectively. Luciferase activity after lipofection of ECs was similarly enhanced 3.3-fold by adjunctive USE. USE had no effect on cell viability, although it inhibited VSMC but not EC proliferation. An alternative strategy is single-dose local administration of agents that can modify the vascular response to injury, including local gene therapy. 1 Viral vectors achieve the highest efficiency, but substantial concerns remain over their clinical safety and long-term efficacy. 1 Although relatively safe, nonviral gene delivery, including lipofection, is currently at least 10-fold less efficient. 1 Ultrasound exposure (USE) has been shown to permeabilize plasma membranes and reduce the thickness of the unstirred layer at the cell surface, 2,3 which should encourage DNA entry into cells. Furthermore, many lipofection reagents contain dioleoylphosphatidylethanolamine (DOPE), which encourages DNA "breakout" from endosomes through a physicochemical transition that is known to be accelerated by USE. 4,5 On the basis of these observations, we investigated the hypothesis that USE may enhance transgene expression after naked DNA and/or liposome-mediated transfection of primary vascular cells. Conclusions-Adjunctive Methods Cell Culture and Transfection ConditionsPorcine medial vascular smooth muscle cells (VSMCs) and lumenal endothelial cells (ECs) from the thoracic aorta of Yorkshire White cross pigs aged Ͻ6 months were cultured in DMEM containing 10% porcine serum; EC cultures were supplemented with EC growth factor (20 g/mL; Sigma) and heparin (90 g/mL; Sigma). All transfections were performed for 3 hours at 37°C in 24-well plates with cells at 60% to 70% confluence and were stopped by dilution with 1 mL of fresh culture medium. Naked DNA transfections were performed in 200 L of DMEM containing 10% porcine serum and 7.5 g/mL luciferase plasmid DNA (pGL3; Promega) per well. Lipofections used Promega Tfx-50 (which contains DOPE), according to conditions optimized for VSMCs (200 L of DMEM containing 10% porcine serum; DNA:lipid charge ratio of 4:1; 7.5 g/mL final DNA concentration) and ECs (200 L of serum-free DMEM; DNA:lipid charge ratio 3:1; 5 g/mL final DNA concentration).Thirty minutes after the transfection was begun, USE was performed for 60 seconds with a custom-built, 10-mm-diameter, 1-MHz ...

BackgroundAtherosclerosis is an inflammatory process that develops in individuals with known risk factors that include hypertension and hyperlipidaemia, influenced by diet. However, the interplay between diet, inflammatory mechanisms and vascular risk factors requires further research. We hypothesised that interleukin-1 (IL-1) signaling in the vessel wall would raise arterial blood pressure and promote atheroma.Methodology/Principal Findings Apoe−/− and Apoe−/−/IL-1R1−/− mice were fed high fat diets for 8 weeks, and their blood pressure and atherosclerosis development measured. Apoe−/−/IL-R1−/− mice had a reduced blood pressure and significantly less atheroma than Apoe−/− mice. Selective loss of IL-1 signaling in the vessel wall by bone marrow transplantation also reduced plaque burden (p<0.05). This was associated with an IL-1 mediated loss of endothelium-dependent relaxation and an increase in vessel wall Nox 4. Inhibition of IL-1 restored endothelium-dependent vasodilatation and reduced levels of arterial oxidative stress.Conclusions/SignificanceThe IL-1 cytokine system links atherogenic environmental stimuli with arterial inflammation, oxidative stress, increased blood pressure and atherosclerosis. This is the first demonstration that inhibition of a single cytokine can block the rise in blood pressure in response to an environmental stimulus. IL-1 inhibition may have profound beneficial effects on atherogenesis in man.

These results suggest that the profile of apoptosis and proliferation after PTCA is regional and cell specific, and attempts to modulate either of these events for therapeutic benefit requires recognition of these differences.