Effects of liver transplantation and resection on lipid parameters: a longitudinal study

The liver plays a vital role in the production and clearance of a large number of lipoproteins and is an important determinant of the plasma levels of various lipids including cholesterol, as well as apoproteins such as apoprotein (a).

To explore the role of the liver in the regulation of lipids and apoprotein concentrations, a serial prospective study measuring lipid parameters and apoprotein (a) levels over 6 months was performed in individuals undergoing hepatic resection for isolated hepatic metastases, transplantation for end-stage liver disease and in individuals undergoing colorectal surgery for malignancy.

In the group with hepatic resection, there was a rapid decrease in total, high density lipoprotein (HDL) and low density lipoprotein (LDL) cholesterol in the immediate postoperative period. However, these changes could be explained by fasting and surgical intervention as a similar phenomenon was observed in the control subjects. In patients undergoing liver transplantation, total cholesterol decreased over the the immediate postoperative period but had fully recovered by day 40. Apoprotein (a) was low pre-operatively, remained low over the first week but had risen by day 10. Apoprotein (a) at day 40 correlated with the apoprotein (a) level of the donor (r = 0.80, P < 0.01) but not of the recipient's pre-operative level and this correlation persisted 6 months after hepatic transplantation.

The liver has a large reserve and is able to maintain lipoprotein production and removal despite greater than 50% removal. The major cause of reduced plasma lipid concentrations in the postoperative period relates to other factors such as fasting and handling of the gut during surgery. In liver transplantation, apoprotein (a) levels resemble those of the donor within 2 weeks of organ donation, consistent with the liver being the major site of production of this apoprotein.