Evaluation of remnant liver function using 13C-breath tests in a rat model of 70% partial hepatectomy.

ABSTRACT

BACKGROUND/AIMS: A 13C breath test was applied to evaluate the early stage of postoperative liver function after hepatectomy. It was examined in comparison with functional and morphological recovery. METHODOLOGY: Rats were subjected to 70% partial hepatectomy (H group) and control group (S group). Expired air, blood and remnant liver tissue were collected at 12, 24, 48 and 72h, and 7 and 14 days postoperatively. Phenylalanine and leucine were used as the 13C-labeled substrates. The 13CO2 was collected until 120min. The mean values of the H and S groups were compared using the highest mean level of 13CO2 excreted in breath (Cmax). The liver regenerative ability was evaluated by Ki-67. RESULTS: In the 13C-phenylalanine breath test, the Cmax value tended to be lower for the H group 12h postoperatively (p=0.06). Cmax was significantly lower for the H group 24h postoperatively (p<0.05). Both groups showed equal recovery at 48h postoperatively. In the 13C-leucine breath test, both groups had no significant difference after hepatectomy. The peak of Ki-67 positive rate is estimated to be at 52.8h postoperatively, meaning that the time difference was only approximately 5h between the peak time of Ki-67 positive rate and the 13C-phenylalanine breath test. CONCLUSIONS: These results strongly support that the 13C-phenylalanine breath test can become a non-invasive indicator to evaluate the early stage of postoperative liver function after hepatectomy.