Systematic reaction to electrolytic treatment of pig livers in vivo

Antitumor effects of electrochemical treatment

Electrochemical treatment is an alternative modality for tumor treatment based on the application of a low intensity direct electric current to the tumor tissue through two or more platinum electrodes placed within the tumor zone or in the surrounding areas. This treatment is noted for its great effectiveness, minimal invasiveness and local effect. Several studies have been conducted worldwide to evaluate the antitumoral effect of this therapy. In all these studies a variety of biochemical and physiological responses of tumors to the applied treatment have been obtained. By this reason, researchers have suggested various mechanisms to explain how direct electric current destroys tumor cells. Although, it is generally accepted this treatment induces electrolysis, electroosmosis and electroporation in tumoral tissues. However, action mechanism of this alternative modality on the tumor tissue is not well understood. Although the principle of Electrochemical treatment is simple, a standardized method is not yet available. The mechanism by which Electrochemical treatment affects tumor growth and survival may represent more complex process. The present work analyzes the latest and most important research done on the electrochemical treatment of tumors. We conclude with our point of view about the destruction mechanism features of this alternative therapy. Also, we suggest some mechanisms and strategies from the thermodynamic point of view for this therapy. In the area of Electrochemical treatment of cancer this tool has been exploited very little and much work remains to be done. Electrochemical treatment constitutes a good therapeutic option for patients that have failed the conventional oncology methods.

Cytokine response of electrolytic ablation in an ex vivo perfused liver model

BACKGROUND

The inflammatory response following hepatic ablation depends on different factors including the method used, the duration and intensity of the treatment and the presence or absence of ischemia. Debate continues about the use of different modalities and whether some aspects of the response may be advantageous by releasing immunological active substances. Little data have been published concerning the cytokine response elicited by hepatic electrolytic ablation (EA). Study of an ex vivo liver model could allow for the evaluation of this response without the influence of confounding systemic factors.

METHODS

Livers explanted from 11 pigs were perfused extracorporeally with normothermic autologous blood. Four of them underwent EA after 1 h of reperfusion. Serum samples were obtained up to 6 h after the reperfusion and assayed for IL-1 beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IFN-gamma, TNF-alpha.

RESULTS

Significant changes in the control group were observed for IL-6 after the second hour and IL-8 after the first hour compared with baseline levels (P < 0.001). In the EA group, IL-6 and IL-12 were raised after the second hour and IL-8 and IL-10 after the first hour (P < 0.001). The comparison between groups showed significant differences for IL-2, IL-4 (decreased in the EA group compared with controls), IL-10 and TNF-alpha (EA group increased compared with controls; P < 0.001).

CONCLUSIONS

The ex vivo perfused liver model demonstrated changes in levels of IL-2, IL-4, IL-10 and TNF-alpha following hepatic EA.

Experimental application of electrolysis in the treatment of liver and pancreatic tumours: principles, preclinical and clinical observations and future perspectives

BACKGROUND

Electrolytic ablation (EA) is a treatment that destroys tissues through electrochemical changes in the local microenvironment. This review examined studies using EA for the treatment of liver and pancreatic tumours, in order to define the characteristics that could endow the technique with specific advantages compared with other ablative modalities.

METHODS

Literature search of all studies focusing on liver and pancreas EA.

RESULTS

A specific advantage of EA is its safety even when conducted close to major vessels, while a disadvantage is the longer ablation times compared to more frequently employed techniques. Bimodal electric tissue ablation modality combines radiofrequency with EA and produced significant larger ablation zones compared to EA or radiofrequency alone, reducing the time required for ablation. Pancreatic EA has been investigated in experimental studies that confirmed similar advantages to those found with liver ablation, but has never been evaluated on patients. Furthermore, few clinical studies examined the results of liver EA in the short-term but there is no appropriate follow-up to confirm any survival advantage.

CONCLUSIONS

EA is a safe technique with the potential to treat lesions close to major vessels. Specific clinical studies are required to confirm the technique's safety and eventually demonstrate a survival advantage.

Bimodal electric tissue ablation-long term studies of morbidity and pathological change

BACKGROUND

Radiofrequency ablation is a popular method of treating unresectable liver tumors but tumors greater than 3 cm in diameter have a much greater risk of local recurrence after treatment. Bimodal electric tissue ablation is a modified form of radiofrequency ablation that creates significantly larger ablations by the addition of extra direct current circuitry. This may help to reduce the risk of local recurrence in these larger tumors. Prior to use in a clinical setting, a long term study was performed to assess associated morbidity and the pathological changes in the ablations.

METHODS

In eight pigs, six ablations were performed in each liver. Pigs were euthanized at 2 d, 2 wk, 2 mo, and 4 mo, and the ablations were assessed macroscopically and microscopically for pathological change. Regular blood tests were performed to assess changes in liver function. At death, any other abnormalities detected were reported.

RESULTS

Histopathological examination of ablation zones revealed tissue death by coagulative necrosis and healing by fibrotic scarring. Transient rises in serum liver enzymes were seen in the postoperative period. Skin necrosis was noted at the site of the positive electrode of the direct electrical current but no other form of morbidity was seen associated with the procedure.

CONCLUSIONS

Although the positive electrode placement requires further consideration, bimodal electric tissue ablation appears to be safe and behaves in a similar fashion to other thermal therapies such as standard radiofrequency ablation.