Background
A small liver remnant is the major limiting factor for hepatectomy. Induction of heme-oxygenase (HO-1) is reported to be the result of various stimuli including ischemia-reperfusion, sepsis, and oxidative stress and confers a beneficial effect. We hypothesize that HO-1 induction occurs after hepatectomy and can be easily measured by assessing its end product, CO being the only source of endogenous production of CO in human.
Methods
Under IRB approval, consecutive patients undergoing hepatectomy with or without microwave ablation were included in this study. Endogenous production of CO in parts per million (ppm) was measured on the exhaled air of these patients preoperatively and four hours and twenty-four hours after liver resection using a CO analyzer (Smokerlyzer, Bedfont Scientific Ltd, England). Liver volumetric measurement was performed using image J software. Student’s t-test was employed to compare groups with p<0.05 considered significant.
Results
Twenty two patients were included. Twelve patients had all recorded measurements of exhaled CO in pre and post resection intervals by the protocol. Preoperative average liver volume was 1845±395 ml. Average resection volume was 170±146 ml, representing an average resection or ablation of 9.2% of liver volume. As compared to baseline (2.03±0.82), there was a statistically significant increase in exhaled CO at four hours (3.11±1.42, p<0.01) and at twenty-four hours (3.00±1.41, p=0.03).
Conclusion
HO-1 is induced by liver resection. HO-1 and its end product CO can play a beneficial role in liver regeneration as was pereviosuly shown in other clinical settings. This could have therapeutic implications for patients undergoing hepatic resection. Further studies will be necessary to identify patient and liver factors that influence the induction of HO-1 as well as its potential beneficial effect on liver regeneration and patient outcomes.
