Hepatic Transport of Indocyanine Green and Bromsulphalein in Two Cases with Discrepancy

Abstract

There were some patients who showed the discrepancy between Indocyanine Green (ICG) and Bromsulphalein (BSP) test. Generally in these patients the BSP retention was higher than ICG. There were few reports about patients who showed high retention of ICG but normal retention of BSP. In this paper two cases with latter type of the discrepancy were reported.
Case I-M.N., 50 year old woman (Cholelithiasis), and Case II-K.M., 32 year old man (duodenal ulcer), were admitted. In both cases the laboratory findings were within normal range except for ICG test. The plasma disappearance rate (K) and retention rate (R) of ICG and BSP were respectively as follows-in Case I K_ICG: 0.023, R_ICG at 15 minutes: 89%, K_BSP: 0.126, R_BSP at 45 minutes: 2.9% and in Case II K_ICG: 0.017, R_ICG: more than 50%, K_BSP: 0.069, R_BSP: 4.5%.
Three fractional transport rates (a, b, h) were calculated from the plasma disappearance curve following a single intravenous injection of ICG and BSP by an established method. The rates in Case I were a_ICG: 0.0255, b_ICG: 0.0158, h_ICG: 0.0423, a_BSP: 0.1331, b_BSP: 0.0091 and h_BSP: 0.0304. From this result a_ICG significantly decreased and it was suggested that the impaired plasma disappearance of ICG was possibly the result of low hepatic uptake of the dye.
The binding activity of serum protein to ICG in vitro was observed by gel filtration on Sephadex G-200. The protein and ICG were respectively eluted in three main peaks. The protein-ICG binding was apparent in the first peak fraction, whereas less in the second and the third peak fraction in normal control. In these two patients the rate of ICG binding to proteins decreased in the first fraction although the pattern of protein-ICG binding was similar to normal control.
The electron-microscopic findings showed the increased reticulum fiber in Disse's space, modification and crystalline-like array of mitochondria, the round cisternae and the small fragments of smooth and rough endoplasmic reticulum and the increase of"lipofuscin-like" lysozome in liver cell.
Abnormal retention of ICG was also recognized in father of Case II. From these results the impaired characteristic hepatic removal of ICG in these patients was suspected to be congenital or constitutional.