UC scientists have discovered that a decades-old technique that causes holes to form in cell membranes can be used for tumor removal with much less danger to the patient than any other current form of surgery.
The technique, known as irreversible electroporation, revisits an old concept.
“”The fact that certain electrical pulses cause irreversible electroporation, permanent defects in the cell membrane, was known since the 1960s,”” UC Berkeley professor and Center for Bioengineering in the Service of Humanity and Society Director Boris Rubinsky stated in an e-mail.
However, when scientists discovered that electric fields could cause defects in cell membranes, they focused their research on developing temporary defects, which enabled them to quickly deliver drugs to cells or even integrate cells into electric circuits. The field became known as reversible electroporation. Irreversible electroporation occurs when the defects are permanent, meaning that targeted cells would die.
Rubinsky worked with Gary Onik, director of the Florida Hospital and Celebration Health’s prostate cancer research program, to develop new technology that could utilize the method for tumor treatment.
Rubinsky and Onik realized the potential for irreversible electroporation to be applied to their work in tumor ablation, the strategic killing of tumor cells as a treatment for cancer. If the defects in the cell membrane do not reseal themselves quickly, it is impossible for the cell to maintain its internal environment, which causes it to die.
“”The reason why the holes occur in the cells is really not fully understood,”” Onik said. “”It is just a phenomenon. … When you apply a bigger field, the holes happen and don’t close.””
Current technology, known as cryosurgery, allows surgeons to freeze the tumor cells, attempting to kill all of them.
“”The part of the technology that is exciting for us is the apparent exactness,”” Onik said. “”When we do … cryosurgery, there is a whole rim or margin of tissue that … just because it freezes doesn’t mean it is going to die. You have to overtreat. This doesn’t have that. This is very exact. One side is alive and one side is dead.””
With the development of irreversible electroporation, damage to surrounding tissue is virtually nonexistent.
“”Electrodes are introduced around the treated region and microsecond electrical pulses are applied to generate the electrical fields that we have found induce irreversible electroporation,”” Rubinsky stated.
This means that only small incisions are needed to insert the electrodes that can be arranged to kill only the tumor, leading to a much faster recovery time for patients.
Even blood vessels and other ducts within the treated tissue survive. Although the cells that compose the walls of the blood vessels actually die, their structure remains in place, which allows them to continue conducting blood and aiding in the recovery of that area.
“”Every current ablation technology affects all components of the tissue,”” Rubinsky stated. “”To the best of my knowledge (I am the co-inventor of the field of imaging-monitored, minimally invasive surgery with Dr. Gary Onik) this is the only technique that affects only the cell membrane by its nature.””
The U.S. Food and Drug Administration has already approved the technology, and its inventors are hoping to start their first patient trials within the next six to eight weeks.
“”If things go well, the way we expect, by this time next year it will probably become widely available,”” Onik said.
If the technique proves to be successful, this technology could also be expanded to other areas. Onik said that irreversible electroporation could be used for liposuction, treating various skin disorders and any other area of medicine where tissues need to be destroyed.
“”I think the important thing is that this isn’t just an incremental step, in the sense that we’re already doing treatments for tumors,”” Onik said, summing up the significance of their find. “”This is really an order of magnitude difference.””
