Initial hepatic microcirculation correlates with early graft function in human orthotopic liver transplantation

Assessment of Hepatic Perfusion in Transplanted Livers by Pharmacokinetic Analysis of Dynamic Magnetic Resonance Measurements

OBJECTIVE

The purpose of this study was to validate the assessment of hepatic perfusion by pharmacokinetic analysis of dynamic contrast-enhanced magnetic resonance image series.

MATERIALS AND METHODS

Dynamic measurements were performed with a saturation recovery turbo fast low angle shot (ie, FLASH) sequence over the course of approximately 4 minutes in 17 patients with transplanted livers. By pharmacokinetic analysis using an open 2-compartment model, we estimated and correlated an amplitude of signal enhancement, A, and the perfusion rate, kp, with invasive perfusion measurements from implanted thermo-diffusion probes (FTDP).

RESULTS

Data analysis for segment IV of the transplanted livers yielded a mean blood flow of 81 +/- 19 mL/min/100g and a mean perfusion rate of 13 +/- 6 minutes. There was a significant correlation between FTDP and kp (rS = 0.64, P = 0.01) but not with A.

CONCLUSIONS

Although our open 2-compartment model oversimplifies the complexity of hepatic perfusion, it allows a numerically robust estimation of regional blood flow per unit of blood volume. Thus, dynamic magnetic resonance imaging represents a noninvasive method to assess hepatic perfusion rate which can be visualized in color coded images.

Molecular adsorbent recirculating system in patients with early allograft dysfunction after liver transplantation: a pilot study

Early allograft dysfunction (EAD) after orthotopic liver transplantation (OLT) causes marked morbidity and mortality. We conducted a prospective pilot study to assess the safety and efficacy of molecular adsorbent recirculating system (MARS) in treatment of EAD after OLT. Twelve consecutive adult liver allograft recipients with a median age of 48 years, 9 of whom were male, were prospectively included and supported with MARS. EAD was defined as the presence of at least 2 of the following: serum bilirubin >10 mg/dL, prothrombin time <40%, aspartate aminotransferase or alanine transferase >1,000 U/L, and plasma disappearance rate of indocyanine green (PDR(ICG)) <10% per minute within 72 hours after reperfusion. One-year patient and graft survival was 66%. There was a significant decrease in serum bilirubin (P = 0.002), serum creatinine (P = 0.006), and aspartate aminotransferase (P = 0.005) and a significant increase in PDR(ICG) (P = 0.007) after MARS treatment. Prothrombin time, albumin level, and platelet count remained stable. Sustained improvement of renal and neurological function and of mean arterial pressure were observed. No MARS-related adverse effects occurred. MARS treatment provides a safe approach to the treatment of EAD after OLT. On the basis of this pilot study, a multicenter randomized clinical trial that uses MARS treatment in EAD after OLT has been initiated.

Effects of matrine on cold ischemia and reperfusion injury during orthotopic liver transplantation in rats

AIM: To investigate the protective effect of matrine on the cold ischemia and reperfusion (I/R) injury during orthotopic liver transplantation (OLT) and its mechanism in rats.

METHODS: Two hundred and twenty-four syngeneic SD rats were randomly divided into control, matrine, and pseudo-treatment group. The rats in matrine group were treated with low (40 mg/kg) and high dose (80 mg/kg) of matrine respectively. After the donor liver was preserved in Ringer's (LR) solution for 5 h, the orthotopic implantation was performed. The serum and tissue samples were collected for analysis 1, 2, 4 and 24 h after reperfusion of the portal vein, and the one-week survival rate was observed in each group.

RESULTS: In comparison with those in the control group, the levels of ALT decreased significantly in low- and high-dose treatment groups at different times post-transplantation, and their one-week survival rates also increased markedly (75%, 75% vs 0, P < 0.01). Matrine treatment decrease the expression of tissue intercellular adhesion molecule-1 (ICAM-1), serum hyaluronic acid (HA) and the adhesion of inflammatory cells to sinusoidal endothelial cells (SEC), and increased the production of nitric oxide (53.1 ± 5.1, 54.2 ± 4.9 μmol/L vs 30.2 ± 2.3 μmol/L, P < 0.01), resulting in suppression of microcirculation injury caused by hepatic reperfusion. The level of endotoxin (ET) was decreased significantly in low- and high-dose treatment groups (0.343 ± 0.111, 0.302 ± 0.059 kEU/L vs 0.643 ± 0.110 kEU/L, P < 0.01), and matrine markedly inhibited the activation of Kupffer cells and the release of tumor necrosis factor-α (1.69 ± 0.22, 1.29 ± 0.33 U/L vs 5.96 ± 0.59 U/L, P < 0.01), and the content of hepatic malondialdehyde (0.87 ± 0.41, 0.69 ± 0.22 μmol/g vs 2.35 ± 0.54 μmol/g, P < 0.01) were notably decreased. Meanwhile, the activity of superoxide dismutase was elevated notably (19.89 ± 1.84, 21.04 ± 1.86 kU/g vs 13.39 ± 0.85 kU/g, P < 0.01). Matrine treatment markedly ameliorated the focal necrosis of hepatocytes, inflammatory cell aggregation, and detachment of SEC. No significant difference was observed between the treated groups.

CONCLUSION: Matrine can prevent hepatic cells and SEC from cold ischemia and reperfusion injury during orthotopic liver transplantation in rats, and the mechanism is associated with the inhibition of Kupffer cell activation and the release of inflammatory cytokines.

Protective Effect of Diltiazem on Hepatic Ischemia-Reperfusion Injury in Rats by Improving Liver Tissue Blood Flow

BACKGROUND

Cytosolic calcium ions are known to play an important role in ischemia-reperfusion (IR) injury. However, the protective effect of calcium channel blockers remains controversial in liver IR injury. Moreover, calcium channel blockers improve hepatic IR injury not due to blocking an increase in hepatic calcium concentration. Therefore, we hypothesized that calcium antagonists protected a liver from IR injury by a vasodilatory action rather than by the inhibition of an increase in Ca2+ within parenchymal cells. This study evaluated the effects of diltiazem, a calcium channel blocker, on liver energy metabolism and blood flow after IR injury.

METHODS

Twenty-seven rats underwent hepatic ischemia for 30 minutes followed by 60 minutes of reperfusion. The animals were allocated into group C (without drug); group D5 (diltiazem, 5 microg/kg per min); or group D10 (diltiazem, 10 microg/kg per min). Diltiazem was infused before laparotomy and then throughout the experiment.

RESULTS

After 60 minutes of reperfusion, liver tissue blood flow and ATP concentrations were significantly higher in group D10 than the other animals (both, P < .05). Changes in ATP values strongly correlated those observed in blood flow (R = 0.80, P < .001).

CONCLUSION

Diltiazem improved ATP-generating capacity during reperfusion by improving liver tissue blood flow. An improvement in hepatic tissue perfusion may be a therapeutic strategy for liver IR injury.

Moderate hypothermia therapy for acute liver failure in rats before liver transplantation

AIM: To observe the effect of moderate hypothermia on the donated livers in rats with acute liver failure (ALF) before liver transplantation.

METHODS: ALF rats model were established by hepatectomy and hepatic devascularization. In situ liver transplantations were carried out for hypothermia treated group (35.0ºC) and the control group (37.5ºC) 12 h after the transplantation. Blood and tissue samples were collected just before and 6 or 24 h after transplantation. The concentrations of TNF-α were compared before and after the transplantation. The content of malondialdehyde (MDA) and the apoptotic rate of hepatic cells after the transplantation were observed. The apoptotic rate and MDA contents in donated liver were also assayed. The morphological changes of liver tissues were observed under microscope.

RESULTS: In the hypothermia treated group, the concentrations of TNF-α before and after the transplantation were significantly lower than those in the control group (19.3±5.9 vs 43.4±9.0 µg/L, t= 5.008, P = 0.007; 6 h, 97.7±18.3 vs 137.1±23.3 µg/L, t = 9.471, P = 0.001); the MDA contents and apoptotic rate after transplantation were also significantly lower than those in the control group (407.1±49.4 vs 598.2±61.8 nmol/L, t = 34.46, P = 0.001; 18.3±3.9% vs 23.6±4.3%, t = 29.63, P = 0.001).

CONCLUSION: Moderate hypothermia can decrease TNF-α level and relieve the damages of the donated liver in rats with ALF.