Functional Elements Associated with Hepatic Regeneration in Living Donors after Right Hepatic Lobectomy1,2

We quantified rates of hepatic regeneration and functional recovery for 6 months after right hepatic lobectomy in living donors for liver transplantation.Twelve donors were studied at baseline; eight retested at (mean±SD) 11±3 days (T1), 10 at 91±9 days (T2), and 10 at 185±17 days (T3) after donation. Liver and spleen volumes were measured by computed tomography (CT) and single photon emission computed tomography (SPECT). Hepatic metabolism was assessed from caffeine and erythromycin, and hepatic blood flow from cholates, galactose, and perfused hepatic mass (PHM, by SPECT).Regeneration rates (mL liver per kg body weight per day) were 0.60±0.22 from baseline to T1, 0.05±0.02 from T1 to T2, 0.01±0.01 from T2 to T3 by CT, 0.54±0.20, 0.04±0.01 and 0.01±0.02 by SPECT. At T3, liver volume was 84±7% of baseline by CT and 92±13% by SPECT. Changes in hepatic metabolism did not achieve statistical significance. At T1, unadjusted clearance ratios relative to baseline were 0.75±0.07 for intravenous cholate (p=0.0001), 0.88±0.15 for galactose (p=0.0681), 0.84±0.08 (p=0.002) for PHM, and 0.83±0.19 (p=0.056) for estimated hepatic blood flow. These ratios approached 1.00 by T3. At T1, ratios adjusted per L liver were 20%-50% greater than baseline and trended toward baseline by T3. Several findings were consistent with alteration of the portal circulation: increased cholate shunt, increased spleen volume, decreased platelet count, and decreased clearance of orally-administered cholate.During the first 2 weeks after donation, hepatic regeneration is rapid and accounts for nearly two-thirds of total regeneration. Increases in hepatic blood flow and uptake of cholate characterize the early phase of regeneration. Right lobe donation alters the portal circulation of living donors, but long-term clinical consequences, if any, are unknown