Sonochemical induction of ABCA1 expression and compositions therefor

Inventors

Coles, Eric • Davidson, Michael

Assignees

Sonothera Inc

Abstract

The present invention provides methods for transfecting cells (e.g., liver cells) to express ABCA1 and increase HDL in the blood. The compositions described herein comprise a pharmaceutically acceptable aqueous carrier containing sonochemically-active microspheres together with a plasmid DNA construct encoding an active form of ABCA1 and at least one promoter for the expression thereof. Preferably, the sonochemically-active microspheres comprise, consist essentially of, or consist of gas bubbles (e.g., a fluorocarbon gas, such as octafluoropropane) encapsulated within protein-containing or lipid-containing shells (e.g., human serum albumin shells). The microspheres are disruptable by exposure to ultrasonic acoustic energy to release the encapsulated gas.

Core Innovation

A method for increasing HDL-cholesterol levels in the blood of a subject is described. The method comprises intravenously co-administering to the subject a plasmid vector encoding the active form of ATP-binding cassette transporter A1 (ABCA1) together with sonochemically-active microspheres. The vector comprises an expressible open reading frame encoding the active form of ABCA1 and at least one sequence adapted to promote expression of the open reading frame in a mammalian cell.

The sonochemically-active microspheres comprise gas bubbles encapsulated within shells comprising a protein, a lipid, or a combination thereof, and the microspheres are disruptable upon exposure to ultrasonic acoustic energy to release the encapsulated gas bubbles. After administration, the method includes ultrasonically imaging a tissue of the subject to be transfected while the plasmid and microspheres are circulating through the vasculature of the tissue, thereby detecting the presence of the microspheres in the vasculature of the tissue.

While the microspheres are present in the tissue, pulses of ultrasonic energy are applied at an acoustical energy level higher than a level required for imaging. The pulses are applied at a sufficient energy level to disrupt the microspheres and release the gas bubbles, and the release of gas bubbles temporarily increases the porosity of cells in the tissue to facilitate entry of the plasmid into the cells. The plasmid transfects the cells and elicits production of an increased level of HDL-cholesterol in the blood of the subject compared to the HDL-cholesterol level prior to administering the plasmid.

The tissue comprises liver tissue, intestinal parenchymal tissue, or a combination thereof, and the method includes applying pulses at an acoustical energy mechanical index (MI) of about 1 to about 2 MI, with a pulse rate of about 6 to 8 pulses per minute and pulse durations in a range of about 500 to about 2000 milliseconds per pulse.

Claims Coverage

Two independent claims are identified. The claims include five inventive features centered on ABCA1 plasmid delivery with sonochemically-active microspheres, ultrasound imaging-based detection, higher-energy ultrasound pulses, increased blood HDL-cholesterol, and specified tissue targeting and pulse parameters.

The claims cover intravenously delivering an ABCA1-encoding plasmid together with sonochemically-active microspheres, using ultrasound imaging to detect microspheres in tissue vasculature, and applying higher-energy ultrasound pulses to disrupt microspheres and release gas bubbles to temporarily increase cell porosity for plasmid entry, resulting in increased blood HDL-cholesterol. One claim further specifies liver and/or intestinal parenchymal tissue and particular pulse rate, pulse duration, and MI ranges.

Stated Advantages

Documented Applications