Age-related changes in liver functional reserve measured by the L-1- 13C-phenylalanine breath test / 中华老年医学杂志

ABSTRACT

Objective:To evaluate liver functional reserve in healthy subjects of different age groups using the L-[1- 13C]-phenylalanine breath test( 13C-pheBT)and to investigate the patterns of changes in liver functional reserve with aging in comparison with elderly cirrhosis patients. Methods:Thirty-seven healthy volunteers were divided into a young and middle-aged group(n=10), an early elderly group(n=9), an advanced elderly group(n=9)and a longevity group(n=9). Eight elderly patients with liver cirrhosis were selected as the control group.An oral dose of 100 mg 13C-phe was administered to each subject.Expired breath samples were collected at pre-dose and at 12 different time points within 150 minutes post-dose.Isotope ratio mass spectrometer was used to measure the abundance of 13C.The percentage of the 13C excretion rate( 13CO 2ERt), the percentage of 13C cumulative excretion( 13Ccumt)at different time points, and the percentage of the 13C peak excretion rate( 13CO 2ERmax)after drug administration were calculated.In addition, associations between 13C-pheBT and common liver function parameters were analyzed. Results:Compared with healthy volunteers, 13CO 2ER 30, 13CO 2ER 45, 13CO 2ER 60, 13Ccum 45, 13Ccum 60, 13Ccum 75, 13Ccum 90 and 13Ccum 105, 13Ccum 120, 13Ccum 135, 13Ccum 150 showed significant differences in the longevity group, the young and middle-aged group and the young elderly group.There were statistically significant differences between the elderly cirrhosis group and the healthy volunteers in each subgroup(all P<0.05); The mean values of 13CO 2ERmax, 13CO 2ER 30, 13Ccum 45, 13Ccum 60, 13Ccum 75, 13Ccum 90, 13Ccum 105, 13Ccum 120, 13Ccum 135, 13Ccum 150 decreased following the order of the young and middle-aged group, the early elderly group, the advanced elderly group, the longevity group, and the elderly cirrhosis group(all P<0.05). In healthy volunteers, the 13CO 2 exclusion rate curve and the cumulative exclusion rate curve showed that the curves of the young and middle-aged group and the early elderly group almost overlapped, while the curves of the advanced group and the longevity group decreased with age, and the difference between the longevity group and the young and middle-aged group and between the longevity group and the early elderly group was markedly prominent. Conclusions:13C-pheBT is a safe, sensitive and reliable test for quantitation of liver function.Our recommendations include collecting samples within an hour of drug administration and using 13CO 2ERmax, 13CO 2ER 30, 13Ccum 45 and 13Ccum 60 as the main parameters.Overall, the functional reserve and compensatory capability of the liver are robust.The decline in liver functional reserve in healthy individuals is a gradual and slow process, with a significant decrease after age 80 and more so after age 90.