Targeting treatment

The effectiveness of many potentially powerful treatments including drug therapy, gene therapy and cancer chemotherapy is often reduced because it can be difficult to target the treatment exactly where it will be most effective. One of the problems is that it is frequently difficult for drugs, as well as DNA and other biological molecules, to pass through the membranes of the targeted cells. Electroporation (EP), which involves the application of electrical pulses directly to the tissue to be treated, is one technique being explored to help overcome this barrier.

In a talk today at the Institute of Physics Dielectrics Group Conference in Canterbury, Dr Dietmar Rabussay of Genetronics Biomedical Ltd., will discuss the background to the development of EP and outline its current and potential applications for clinical use. Genetronics, based in San Diego, California, USA, has developed a broad range of EP treatments. It also develops scientific instruments that can be used to perform various types of electroporation experiments.

Electroporation involves directly applying electrical pulses of millionths of a second duration and field strengths of 100-1500 volts per centimetre to living cells. The electrical pulses cause microscopic pores to open up through the cell?s membrane. When the electric pulse stops, the pores close again, trapping the drug or DNA inside the cell. EP can be carried out by applying the electrical pulses either directly to the target tissue to be treated in a living organism, or to cell suspensions and isolated organs.

The technique, Dr Rabussay believes, has opened up the potential for new approaches to medical problems where successful treatment depends on finding ways for the therapeutic molecules to reach the cell interior. This includes – among others – treatments such as cancer chemotherapy, the delivery of DNA for gene therapy and DNA vaccines, the delivery of drugs for treating cardiac and vascular problems as well as the treatment of the eye disease, glaucoma.

“Some of these applications – including the treatment of cancerous head and neck tumours are already in advanced clinical development,” Dr Rabussay reports. “Many other potential applications such as the treatment of haemophilia and other genetic defects or the treatment of cardiovascular diseases and the prevention of atherosclerosis are in early development or are still waiting to be explored.”