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Objective: To elucidate the transfected effect of albumin ultrasound microbubbles carrying peptide nucleic acids (PNAs) against c-myc gene to the vascular walls and their effect on the intimal proliferation induced by vascular denudation. Methods: A rabbit iliac artery intimal proliferation model was constructed and PNA against c-myc mRNA was designed and synthesized and was added to albumin solution before ultrasound microbubbles were prepared and encapsulated in matrix of albumin. The ultrasound microbubbles carrying PNA were transfected to intima under ultrasound exposure. The transfected effect was identified by a histochemical method and the expression of c-myc was detected byin situhybridization. The proliferation of intimal smooth muscle cells was estimated by the expression of proliferative cell nuclear antigen (PCNA) of them. The intimal area and thickness were judged morphologically for intimal hyperplasia. Results: The ultrasound microbubbles with PNA were successfully prepared and c-myc PNA was transfected to vascular intimal cells. The expression of c-myc and PCNA by intimal vascular smooth muscle cells (vSMCs) was inhibited significantly and the intimal thickness and area were reduced remarkably. Conclusion: Transfection of c-myc PNA could inhibit proliferartion of vSMCs and intima in the rabbit iliac artery intimal proliferation model and the targeted transfection of albumin ultrasound microbubbles carrying PNA offers a feasible way to facilitate its access to specific cellsin vivoand produce bioavailability. [ABSTRACT FROM AUTHOR]

Aims: To observe the effect of constructed ultrasound microbubble crosslinked to albium nanoparticles packaged with tissue-type plasminogen activator (tPA) gene plasmid on the in vivo transfection. Methods: The rabbits were chosen for all experiments. A highly expressive gene plasmid for tPA was constructed and packaged into a prepared nanoparticle with bovine serum albumin (BSA). This albium nanoparticle packaged with tPA gene plasmid was crosslinked to an ultrasound microbubble prepared with BSA and sucrose to form a nano-targeting vector system for tPA gene transfection. The transfection and effective expression of tPA in heart, liver, leg skeletal muscle and the cervical rib were detected with polyclonal antibodies to tPA using immunohistochemical method; the tPA level and D-dimer content of blood were also tested. Results: The expression of tPA could be seen in the tissues mentioned above, with the increase in blood tPA level and D-dimer content from 0.20 ± 0.05 μg/L and 81.76 ± 9.84 μg/L before the operation, to the higher levels of 0.44 ± 0.05 μg/L and 669.28 ± 97.74 μg/L after transfection. Conclusion: The nano-targeting vector system for tPA gene was contructed successfully. This provides a new theory and experimental method for the nano-targeted transgene. [ABSTRACT FROM AUTHOR]

Background: There are more than 300,000 prosthetic heart valve replacements each year worldwide. These patients are faced with a higher risk of thromboembolic events after heart valve surgery and long-term or even life-long anticoagulative and antiplatelet therapies are necessary. Some severe complications such as hemorrhaging or rebound thrombosis can occur when the therapy ceases. Tissue-type plasminogen activator (t-PA) is a thrombolytic agent. One of the best strategies is gene therapy, which offers a local high expression of t-PA over a prolonged time period to avoid both systemic hemorrhaging and local rebound thrombosis. There are some issues with t-PA that need to be addressed: currently, there is no up-to-date report on how the t-PA gene targets the heart in vivo and the gene vector for t-PA needs to be determined., Aims: To fabricate an albumin nano-t-PA gene ultrasound-targeted agent and investigate its targeting effect on prevention of thrombosis after heart mechanic valve replacement under therapeutic ultrasound., Methods: A dog model of mechanical tricuspid valve replacement was constructed. A highly expressive t-PA gene plasmid was constructed and packaged by nanoparticles prepared with bovine serum albumin. This nanopackaged t-PA gene plasmid was further cross-linked to ultrasonic microbubbles prepared with sucrose and bovine serum albumin to form the ultrasonic-targeted agent for t-PA gene transfection. The agent was given intravenously followed by a therapeutic ultrasound treatment (1 MHz, 1.5 w/cm(2), 10 minutes) of the heart soon after valve replacement had been performed. The expression of t-PA in myocardium was detected with multiclonal antibodies to t-PA by the indirect immunohistochemical method. Venous blood t-PA and D-dimer contents were tested before and 1, 2, 4, and 8 weeks after the operation., Results: The high expression of t-PA could be seen in myocardium with increases in blood t-PA and D-dimer contents and thrombosis was prevented 8 weeks after operation., Conclusion: We successfully fabricated an albumin nano-t-PA gene ultrasound-targeted agent that could prevent dog thrombosis after mechanical heart valve replacement. Our study provides an experimental basis for prevention of human thrombosis-related diseases.