The within-individual reproducibility of the disease severity index from the HepQuant SHUNT test of liver function and physiology.

The HepQuant SHUNT test quantifies liver function and blood flow using systemic and portal clearances of cholate. The test can identify the risk of well-compensated patients to develop complications of cirrhosis. To confirm the reliability of a single HepQuant SHUNT test we defined its within-individual reproducibility. Healthy subjects (n = 16), 16 with nonalcoholic steatohepatitis (NASH), and 16 with chronic hepatitis C virus (HCV) underwent 3 HepQuant SHUNT tests on 3 separate days within 30 days. The test involves simultaneous administration of 20 mg 13C-cholate IV and 40 mg d4-cholate PO, and subsequent collection of 3 mL blood samples at 5, 20, 45, 60, and 90 minutes. Clearances are expressed as systemic and portal hepatic filtration rate. Portal-systemic shunting (SHUNT), a disease severity index (DSI), and an estimate of DSI (STAT) are calculated from the clearances. Reproducibility was determined by the intraclass correlation coefficient (ICC > 0.70) and Bland-Altman analysis. Equal numbers of NASH and HCV patients had either early (F0-F2) or advanced (F3/F4) stages of fibrosis. All F3/F4 subjects were clinically compensated. The intraclass correlation coefficient (ICC) for DSI was 0.94 (0.90-0.96 95% confidence interval) indicating excellent reproducibility. The other test parameters had ICCs ranging from 0.74 (SHUNT) to 0.90 (STAT). In Bland-Altman analysis, the mean of differences between measurements of DSI was 0.13 with standard deviation 2.12. The excellent reproducibility of the HepQuant SHUNT test, particularly DSI, supports the use this minimally invasive, blood-based test as a reliable test of liver function and physiology.

Functional elements associated with hepatic regeneration in living donors after right hepatic lobectomy.

We quantified the rates of hepatic regeneration and functional recovery for 6 months after right hepatic lobectomy in living donors for liver transplantation. Twelve donors were studied pre-donation (baseline); 8 were retested at a mean ± SD of 11±3 days after donation (T1), 10 were retested at a mean of 91±9 days after donation (T2), and 10 were retested at a mean of 185±17 days after donation (T3). Liver and spleen volumes were measured with computed tomography (CT) and single-photon emission computed tomography (SPECT). Hepatic metabolism was assessed with caffeine and erythromycin, and hepatic blood flow (HBF) was assessed with cholates, galactose, and the perfused hepatic mass (PHM) by SPECT. The regeneration rates (mL kg(-1) of body weight day(-1)) by CT were 0.60±0.22 mL from the baseline to T1, 0.05±0.02 mL from T1 to T2, and 0.01±0.01 from T2 to T3; by SPECT they were 0.54±0.20, 0.04±0.01, and 0.01±0.02, respectively. At T3, the liver volumes were 84%±7% of the baseline according to CT and 92%±13% of the baseline according to SPECT. Changes in the hepatic metabolism did not achieve statistical significance. At T1, the unadjusted clearance ratios with respect to the baseline were 0.75±0.07 for intravenous cholate (P<0.001), 0.88±0.15 for galactose (P=0.07), 0.84±0.08 for PHM (P=0.002), and 0.83±0.19 for the estimated HBF (P=0.06). At T1, these ratios adjusted per liter of liver were up to 50% greater than the baseline values, suggesting recruitment of HBF by the regenerating liver. Increased cholate shunt, increased spleen volume, and decreased platelet count, were consistent with an altered portal circulation. In conclusion, initial hepatic regeneration is rapid, accounts for nearly two-thirds of total regeneration, and is associated with increases in HBF and cholate uptake. Right lobe donation alters the portal circulation of living donors, but the long-term clinical consequences, if there are any, are unknown.

Activation-dependent adsorption of cytokines and toxins related to liver failure to carbon beads.

In the course of severe pathological conditions, such as acute liver failure and sepsis, toxic metabolites and mediators of inflammation are released into the patient's circulation. One option for the supportive treatment of these conditions is plasmapheresis, in which plasma, after being separated from the cellular components of the blood, is cleansed by adsorption of harmful molecules on polymers or activated carbon. In this work, the adsorption characteristics of activated carbon beads with levels of activation ranging from 0 to 86% were assessed for both hydrophobic compounds accumulating in liver failure (bilirubin, cholic acid, phenol and tryptophan) and cytokines (tumor necrosis factor α and interleukin-6). Progressive activation resulted in significant gradual reduction of both bulk density and mean particle size, in an increase in the specific surface area, and to changes in pore size distribution with progressive broadening of micropores. These structural changes went hand in hand with enhanced adsorption of small adsorbates, such as IL-6 and cholic acid and, to a lesser extent, also of large molecules, such as TNF-α.

Acute effects of intravenous infusion of ApoA1/phosphatidylcholine discs on plasma lipoproteins in humans.

To investigate the metabolism of nascent HDLs, apoA1/phosphatidylcholine (apoA1/PC) discs were infused IV over 4 hours into 7 healthy men. Plasma total apoA1 and phospholipid (PL) concentrations increased during the infusions. The rise in plasma apoA1 was greatest in small prebeta-migrating particles not present in the infusate. Total HDL unesterified cholesterol (UC) also increased simultaneously. After stopping the infusion, the concentrations of apoA1, PL, HDL UC, and small prebeta HDLs decreased, whereas those of HDL cholesteryl ester (CE) and large alpha-migrating apoA1 containing HDLs increased. ApoB-containing lipoproteins became enriched in CEs. Addition of apoA1/PC discs to whole blood at 37 degrees C in vitro also generated small prebeta HDLs, but did not augment the transfer of UC from erythrocytes to plasma. We conclude that the disc infusions increased the intravascular production of small prebeta HDLs in vivo, and that this was associated with an increase in the efflux and esterification of UC derived from fixed tissues. The extent to which the increase in tissue cholesterol efflux was dependent on that in prebeta HDL production could not be determined. Infusion of discs also reduced the plasma apoB and apoA2 concentrations, and increased plasma triglycerides and apoC3. Thus, nascent HDL secretion may have a significant impact on prebeta HDL production, reverse cholesterol transport and lipoprotein metabolism in humans.