Evaluation of Remnant Liver Function using 13C-Breath Tests in a Rat Model of 70% Partial Hepatectomy

Abstract

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. 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. 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. 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.