By Brett Kotowski BME 281 Section 2 IRREVERSIBLE ELECTROPORATION
Irreversible Electroporation (IRE) is the permeabilization of a cell membrane by use of an applied electric field. It is a minimally invasive procedure that uses electrical probes to permeate through the cell membrane of a tumor and kill the cancer cells inside the tumor. It is just beginning to be used in the medical field as a possible replacement for chemotherapy, radiation treatment, as well as electro chemotherapy.
THE ORIGINS OF ELECTROPORATION Electroporation originated with two men, Okino and Mohri in 1987 who independently discovered that the permeablity of cell membrane can be increased by the use of reversible electric pulses, combined with anticancer drugs. This process is referred to as reversible electroporation or electro chemotherapy. The problem with this particular procedure is that it combines the use of an electric field along with combinations of chemical agents.
THE ORIGINS OF ELECTROPORATION Ultimately, irreversible electroporation was derived from reversible electroporation. This discussion of this new method was described by Davalos et al. In 2005. This group of engineers discovered that electrical pulse treatment can be applied to a tumor without the use of cytotoxic cancer drugs. They conducted tests with models of the liver and found that the tumor size is greatly reduced due to the applied electric field. They also stated in their research that a unique aspect of irreversible electroporation is that the affected area can be controlled and monitored with electrical impedance tomography.
IRREVERSIBLE ELECTROPORATION: HOW IT WORKS In IRE it begins with the electric probes that are affectively used as needles in the procedure. These electrical probes emit electrical pulses across the membrane of a tumor. The electrical pulses create an electric field across the membrane. The voltage generated from this electric field targets the cancer cells and destroys them.
IRE IN TESTING WITH MICE In 2007 the first live testing done with IRE was done with mice. Mice were fist anesthetized at the start of the procedure, and an incision was made to lift the skin flap covering the tumor. Stainless-steel electrodes were placed on both sides of the tumor. The voltage of the electric field was monitored and the tumors were removed from the mice following the experiment. This resulted in 12 out of 13 completely regressed tumors in the mice that were tested.
PRIMARY USES OF IRE Irreversible electroporation will mainly be applied to areas of soft tissue. These areas include the pancreas, liver, kidneys, prostate and lungs. These areas are the main target areas of irreversible electroporation because these areas are located near blood vessels.
NANOKNIFE® SYSTEM The Nanoknife® system created by Angiodynamics was granted approval by the FDA for surgical ablation of soft tissue in 2009. The Nanoknife sytem applies the methods of irreversible electroportation to permanently open cell membranes of tumors. Healthy tissue then has the oppurtunity to grow and populate the area where the dead tissue now lies.
THE PROCEDURE Doctors fist map where the tumor is using computed tomography scans. The patient is then placed under general anesthesia. The probes are then placed all around the tumor to create the electric field, and pulses of less than 100 microseconds are delivered to the tumor, opening and killing the cancer cells. This procedure results in minimal scarring due to the way the cancer cells are just opened and eliminated.
Nanoknife system costs $300,000, and each electric probe costs $2,000 making for expensive treatment. The Nanoknife system is designed mainly for small tumors, and would be rather ineffective with larger tumors. It is minimally invasive surgery that allows for quicker recovery time. The destruction of the tumor is monitored throughout the procedure to assure the target area is being tended to. IRE does substantial less harm to the body than chemotherapy or raditation. ADVANTAGES AND DISADVANTAGES OF IRREVERSIBLE ELECTROPORATION AdvantagesDisadvantages
CONCLUSION Irreversible electroporation is a tremendous step for the treatment of cancer. It is far less painful that the current treatments that are employed now, and is quite affective in eliminating the cancer cells in the cell membrane. It is a very benign procedure because it only destroys the bad tissue, leaving healthy tissue unharmed. Patients can have quick recovery times with little scarring or pain following the surgery. With further research the Nanoknife system will be able to destroy larger tumors on a wider variety of areas on the body.
WORKS CITED B, Al-Sakere, et al. "Tumor Ablation with Irreversible Elecrtoporation." Plos One 2.11 (2007): 1- 24. Print. Davalos, Rafael V., L. M. Mir, and B. Rubinsky. "Tissue Ablation with Irreversible Technology." Annals of Biomedical Engineering 33.2 (2005): 223-31. Print. "Radiologists at UMMC Use New Electric-Pulse Technology to Target Tumors." University of Maryland Medical Center. University of Maryland Medical Center, n.d. Web. 12 Oct. 2013.. Tasker, Fred. "Some Doctors Tout Nanoknife for Tumor Removal." The Seattle Times 8 Feb. 2010: n. pag. The Seattle Times. Web. 14 Oct. 2013.. "Technology." Baptist Health. Baptist Health, n.d. Web. 12 Oct. 2013.. wikipedia. N.p., n.d. Web. 12 Oct. 2013.