Sustained spatial disturbance of bile canalicular networks during regeneration of the steatotic rat liver

Bile Acid Overload Induced by Bile Duct and Portal Vein Ligation Improves Survival after Staged Hepatectomy in Rats

OBJECTIVE

Compared to portal vein ligation (PVL), simultaneous bile duct and portal vein ligation (BPL) can significantly enhance hypertrophy of the intact liver. This study aimed to investigate whether BPL could improve survival after extended hepatectomy independently of an increased remnant liver.

METHODS

We adopted rat models of 90% BPL or 90% PVL. To investigate the role of bile acids (BAs) the BA pools in the PVL and BPL groups were altered by the diet. Staged resection preserving 10% of the estimated liver weight was performed 3 days after BPL; PVL; or sham operation. Histology, canalicular network (CN) continuity; and hepatocyte polarity were evaluated.

RESULTS

At 3 days after BPL; PVL; or sham operation when the volumetric difference of the intended liver remained insignificant, the survival rates after extended hepatectomy were 86.7%, 47%, and 23.3%, respectively (P<0.01). BPL induced faster restoration of canalicular integrity along with an intensive but transient BA overload. Staged hepatectomy after BPL shortened the duration of the bile CN disturbance and limited BA retention. Decreasing the BA pools in the rats that underwent BPL could compromise these effects, whereas increasing the BA pools of rats that underwent PVL could induce similar effects. The changes in CN restoration were associated with activation of LKB1.

CONCLUSION

In addition to increasing the future remnant liver, BPL shortened the duration of the spatial disturbance of the CN and could significantly improve the tolerance of the hypertrophied liver to staged resection. BPL may be a safe and efficient future option for patients with an insufficient remnant liver.

Liver regeneration after performing associating liver partition and portal vein occlusion for staged hepatectomy (ALPPS) is histologically similar to that occurring after liver transplantation using a small-for-size graft

PURPOSE

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) can achieve marked future liver remnant (FLR) hypertrophy but this procedure is associated with a risk of mortality due to liver failure because of an insufficient FLR functional increase, a situation comparable to small-for-size syndrome (SFSS) after living-donor liver transplantation (LDLT).

METHODS

The clinical data, morphologic volume changes, and histopathologic and immunohistochemical findings in hepatocytes and bile ductules were compared between ALPPS (n = 10) and LDLT with a risk for SFSS (n = 12).

RESULTS

Although the patient characteristics and short-term outcome differed between the groups, the mean hypertrophy ratios with respect to liver volume for the FLR after performing the first-stage ALPPS procedures resembled those in small-for-size grafts after similar time intervals: 1.702 ± 0.407 in ALPPS vs. 1.948 ± 0.252 in LDLT (P = 0.205). The histologic grades for sinusoidal dilation (P = 0.896), congestion (P = 0.922), vacuolar change (P = 0.964), hepatocanalicular cholestasis (P = 0.969), and ductular reaction (P = 0.728) within the FLR at the second-stage operation during ALPPS or implanted graft were all similar between the groups.

CONCLUSIONS

The hepatic regenerative process may be similar in ALPPS and LDLT using a small-for-size graft. Reducing the hepatic vascular inflow that may be excessive for the FLR volume during the first stage of ALPPS might enhance the functional recovery since measures with a similar effect appear to lessen the likelihood of SFSS.

Alpha-2-Macroglobulin and Albumin are Useful Serum Proteins to Detect Subclinical Peritonitis in the Rat

Background

In experimental peritoneal dialysis (PD) studies, the occurrence of peritonitis is a confounder in the interpretation of effects of chronic peritoneal exposure to dialysis solutions. Since fluid cannot be drained in most experimental PD models in the rat, it is impossible to diagnose peritonitis based on dialysate white blood cell counts. To study the value of serum markers for the presence of peritonitis, alpha-2-macroglobulin (α2M) and albumin were measured in rats with and without peritonitis after chronic exposure to dialysis solutions. To further investigate the time course of these markers in relation to the severity of peritonitis, nondialyzed rats were challenged with increasing numbers of bacteria and followed for 28 days.

Methods

In the first study, α2M and albumin were measured in rats exposed to glucose/lactate-based dialysis fluid before sacrifice. A comparison was made between animals with peritonitis, as judged from the presence of extensive infiltrates after sacrifice (gold standard) and/or clinical signs of peritonitis, or absence of peritonitis and infiltrates. In the second study, rats were intraperitoneally (IP) injected with 3 different concentrations of Staphylococcus aureus, and serum α2M and albumin were measured at various time points.

Results

In the first study, serum α2M was higher and serum albumin was lower in animals with peritonitis compared to animals without peritonitis (both p < 0.05). In the second study, induction of α2M was clearly dependent on the inoculum concentration. Peak values of α2M were found at days 1 and 3. At all time points after inoculation, α2M was higher in all injected groups compared to the control group. Serum albumin values decreased in the highest inoculum group and remained decreased until 28 days after IP injection. Despite a low sensitivity, serum α2M >40 mg/L and albumin <32 g/L had a specificity of 100% for peritonitis.

Conclusions

Measurement of α2M and albumin once per month is an additional tool in the diagnosis of silent peritonitis in the chronic peritoneal exposure model in the rat. Levels of α2M >40 mg/L and albumin <32 g/L are strong indicators for peritonitis. However, normal values do not exclude infectious peritonitis.

Preserved liver regeneration capacity after partial hepatectomy in rats with non-alcoholic steatohepatitis

AIM

To evaluate the liver regeneration capacity (LRC) after partial hepatectomy (PH) in experimental non-alcoholic steatohepatitis (NASH).

METHODS

Fifty-four female rats were fed a high-fat, high-cholesterol diet (HFCD, 65% fat, 1% cholesterol) or standard diet (STD) for 16 wk. A 70% PH was performed and the animals were euthanised before PH or 2 or 5 d post-PH. LRC was evaluated using: The total number of Ki-67 positive hepatocytes in the caudate lobe, N(Ki-67, lobe) evaluated in a stereology-based design, the regenerated protein ratio (RPR), prothrombin-proconvertin ratio (PP), and mRNA expression of genes related to regeneration.

RESULTS

The HFCD NASH model showed significant steatosis with ballooning and inflammation, while no fibrosis was present. Mortality was similar in HFCD and STD animals following PH. HFCD groups were compared to respective STD groups and HFCD animals had a significantly elevated alanine transaminase at baseline (P < 0.001), as well as a significantly elevated bilirubin at day 2 after PH (P < 0.05). HFCD animals had a higher N(Ki-67, lobe) at baseline, (P < 0.0001), day 2 after PH (P = 0.06) and day 5 after PH (P < 0.025). We found no significant difference in RPR or PP neither 2 or 5 d post-PH. Expression of liver regeneration genes (e.g., hepatic growth factor) was higher at both day 2 and 5 post-PH in HFCD groups (P < 0.05).

CONCLUSION

NASH rats had a preserved LRC after hepatectomy when compared to STD rats. The methods and models of NASH are essential in understanding and evaluating LRC.

Inhibition of bile canalicular network formation in rat sandwich cultured hepatocytes by drugs associated with risk of severe liver injury

Idiosyncratic drug-induced liver injury is a clinical concern with serious consequences. Although many preclinical screening methods have been proposed, it remains difficult to identify compounds associated with this rare but potentially fatal liver condition. Here, we propose a novel assay system to assess the risk of liver injury. Rat primary hepatocytes were cultured in a sandwich configuration, which enables the formation of a typical bile canalicular network. From day 2 to 3, test drugs, mostly selected from a list of cholestatic drugs, were administered, and the length of the network was semi-quantitatively measured by immunofluorescence. Liver injury risk information was collected from drug labels and was compared with in vitro measurements. Of 23 test drugs examined, 15 exhibited potent inhibition of bile canalicular network formation (<60% of control). Effects on cell viability were negligible or minimal as confirmed by lactate dehydrogenase leakage and cellular ATP content assays. For the potent 15 drugs, IC50 values were determined. Finally, maximum daily dose divided by the inhibition constant gave good separation of the highest risk of severe liver toxicity drugs such as troglitazone, benzbromarone, flutamide, and amiodarone from lower risk drugs. In conclusion, inhibitory effect on the bile canalicular network formation observed in in vitro sandwich cultured hepatocytes evaluates a new aspect of drug toxicity, particularly associated with aggravation of liver injury.

Macrosteatotic and nonmacrosteatotic grafts respond differently to intermittent hepatic inflow occlusion: Comparison of recipient survival

Intermittent hepatic inflow occlusion (IHIO) during liver graft procurement is known to confer protection against graft ischemia/reperfusion injury and thus may benefit the recipient's outcome. We evaluated whether the protective effect of IHIO differs with the presence of macrosteatosis (MaS) and with an increase or decrease in the cumulative occlusion time. The subgroup of 188 recipients who received grafts with MaS was divided into 3 groups according to the number of total IHIO rounds during graft procurement: no IHIO, n = 70; 1 to 2 rounds of IHIO, n = 50; and ≥3 rounds of IHIO, n = 68. Likewise, the subgroup of 200 recipients who received grafts without MaS was divided into 3 groups: no IHIO, n = 108; 1 to 2 rounds of IHIO, n = 40; and ≥3 rounds of IHIO, n = 52. The Cox model was applied to evaluate the association between the number of total IHIO rounds and recipient survival separately in the subgroup of MaS recipients and the subgroup of non-MaS recipients. Analyzed covariables included the etiology, Milan criteria, transfusion, immunosuppression, and others. In the subgroup of MaS recipients, 1 to 2 rounds of IHIO were favorably associated with recipient survival [hazard ratio (HR), 0.29; 95% confidence interval (CI), 0.10-0.80; P = 0.03 after Bonferroni correction], whereas ≥3 rounds of IHIO were not associated with recipient survival (HR, 0.56; 95% CI, 0.25-1.23). In the subgroup of non-MaS recipients, neither 1 to 2 rounds of IHIO (HR, 0.69; 95% CI, 0.30-1.61) nor ≥3 rounds of IHIO (HR, 0.91; 95% CI, 0.42-1.96) were associated with recipient survival. In conclusion, 1 to 2 rounds of IHIO may be used for the procurement of MaS grafts with potential benefit for recipient survival, whereas IHIO has a limited impact on recipient survival regardless of the cumulative occlusion time when it is used for non-MaS grafts.

Elevated sensitivity of macrosteatotic hepatocytes to hypoxia/reoxygenation stress is reversed by a novel defatting protocol

Macrosteatotic livers exhibit elevated intrahepatic triglyceride (TG) levels in the form of large lipid droplets (LDs), reduced adenosine triphosphate (ATP) levels, and elevated reactive oxygen species (ROS) levels, and this contributes to their elevated sensitivity to ischemia/reperfusion injury during transplantation. Reducing macrosteatosis in living donors through dieting has been shown to improve transplant outcomes. Accomplishing the same feat for deceased donor grafts would require ex vivo exposure to potent defatting agents. Here we used a rat hepatocyte culture system exhibiting a macrosteatotic LD morphology, elevated TG levels, and an elevated sensitivity to hypoxia/reoxygenation (H/R) to test for such agents and ameliorate H/R sensitivity. Macrosteatotic hepatocyte preconditioning for 48 hours with a defatting cocktail that was previously developed to promote TG catabolism reduced the number of macrosteatotic LDs and intracellular TG levels by 82% and 27%, respectively, but it did not ameliorate sensitivity to H/R. Supplementation of this cocktail with l-carnitine, together with hyperoxic exposure, yielded a similar reduction in the number of macrosteatotic LDs and a 57% reduction in intrahepatic TG storage, likely by increasing the supply of acetyl coenzyme A to mitochondria, as indicated by a 70% increase in ketone body secretion. Furthermore, this treatment reduced ROS levels by 32%, increased ATP levels by 27% (to levels near those of lean controls), and completely abolished H/R sensitivity as indicated by approximately 85% viability after H/R and the reduction of cytosolic lactate dehydrogenase release to levels seen in lean controls. Cultures maintained for 48 hours after H/R were approximately 83% viable and exhibited superior urea secretion and bile canalicular transport in comparison with untreated macrosteatotic cultures. In conclusion, these findings show that the elevated sensitivity of macrosteatotic hepatocytes to H/R can be overcome by defatting agents, and they suggest a possible route for the recovery of discarded macrosteatotic grafts.

Comparison of the tolerance of hepatic ischemia/reperfusion injury in living donors: macrosteatosis versus microsteatosis

A safe use of intermittent hepatic inflow occlusion (IHIO) has been reported for living donor hepatectomy. However, it remains unclear whether the maneuver is safe in steatotic donors. In addition, the respective importance of macrosteatosis (MaS) and microsteatosis (MiS) is an important issue. Thus, we compared MiS and MaS with respect to the tolerance of hepatic ischemia/reperfusion (IR) injury induced by IHIO. One hundred forty-four donors who underwent a right hepatectomy were grouped according to the presence of MaS and MiS: a non-MaS group (n = 68) versus an MaS group (n = 76) and a non-MiS group (n = 51) versus an MiS group (n = 93). The coefficients of the regression lines between the cumulative IHIO time and the peak postoperative transaminase concentrations were used as surrogate parameters indicating the tolerance of hepatic IR injury. The coefficients were significantly greater for the MaS group versus the non-MaS group (4.12 ± 0.59 versus 2.22 ± 0.46 for alanine aminotransferase, P = 0.01). Conversely, the MiS and non-MiS groups were comparable. A subgroup analysis of donors who underwent IHIO for >30 minutes showed that MaS significantly increased the transaminase concentrations, whereas MiS had no impact. Also, IHIO for >30 minutes significantly increased the biliary complication rate for MaS donors (12.1% for ≤ 30 minutes versus 32.6% for >30 minutes, P = 0.04), whereas MiS donors were not affected. In conclusion, the tolerance of hepatic IR injury might differ between MaS livers and MiS livers. It would be rational to assign more clinical importance to MaS versus MiS. We further recommend limiting the cumulative IHIO time to 30 minutes or less for MaS donors undergoing right hepatectomy.

Effect of pure microsteatosis on transplant outcomes after living donor liver transplantation: a matched case-control study

Liver steatosis mostly exists in a mixed form of macrosteatosis (MaS) and microsteatosis (MiS). This coexistence is responsible for previous conflicting results regarding the importance of MiS in liver transplantation. We aimed to evaluate the independent effect of MiS on posttransplant outcomes with the exclusion of the confounding effect of MaS. Seventy-one living donors who had pure MiS (defined as an MiS degree > 5% without MaS) were matched 1:1 with control donors, and 66 recipients who received pure MiS grafts were matched 1:1 with control recipients on the basis of propensity scores. Matched variables included the donor age, remnant liver volume, cold ischemia time, graft-to-recipient weight ratio and Model for End-Stage Liver Disease score. The degree of pure MiS ranged from 5% to 50%. Donors in the control and pure MiS groups were comparable with respect to peak postoperative transaminase concentrations [alanine aminotransferase (ALT): 194 versus 176 IU/L, P = 0.61] and postoperative complications. Recipients in the control and pure MiS groups were comparable with respect to recipient (P = 0.15) and graft survival rates (P = 0.56) as well as peak postoperative transaminase concentrations (ALT: 266 versus 281 IU/L, P = 0.88), and graft regeneration rates at 2 weeks (61% versus 59%, P = 0.73). The 2 groups were also comparable with respect to major complications, primary graft dysfunction/nonfunction, intensive care unit/hospital stays, and metabolic diseases. In conclusion, MiS alone does not seem to impair the posttransplant outcomes of living donors and their recipients. The interaction between MiS and MaS, and the effect of a greater degree of MiS are the next important topics to be further evaluated in the mixed steatosis population.

Rat hepatocyte culture model of macrosteatosis: effect of macrosteatosis induction and reversal on viability and liver-specific function

BACKGROUND & AIMS

A common cause of liver donor ineligibility is macrosteatosis. Recovery of such livers could enhance donor availability. Living donor studies have shown diet-induced reduction of macrosteatosis enables transplantation. However, cadaveric liver macrosteatotic reduction must be performed ex vivo within hours. Towards this goal, we investigated the effect of accelerated macrosteatosis reduction on hepatocyte viability and function using a novel system of macrosteatotic hepatocytes.

METHODS

Hepatocytes isolated from lean Zucker rats were cultured in a collagen sandwich, incubated for 6 days in fatty acid-supplemented medium to induce steatosis, and then switched for 2 days to medium supplemented with lipid metabolism promoting agents. Intracellular lipid droplet size distribution and triglyceride, viability, albumin and urea secretion, and bile canalicular function were measured.

RESULTS

Fatty acid-supplemented medium induced microsteatosis in 3 days and macrosteatosis in 6 days, the latter evidenced by large lipid droplets dislocating the nucleus to the cell periphery. Macrosteatosis significantly impaired all functions tested. Macrosteatosis decreased upon returning hepatocytes to standard medium, and the rate of decrease was 4-fold faster with supplemented agents, yielding 80% reduction in 2 days. Viability of macrosteatosis reduced hepatocytes was similar to control lean cells. Accelerated macrosteatotic reduction led to faster recovery of urea secretion and bile canalicular function, but not of albumin secretion.

CONCLUSIONS

Macrosteatosis reversibly decreases hepatocyte function and supplementary agents accelerate macrosteatosis reduction and some functional restoration with no effect on viability. This in vitro model may be useful to screen agents for macrosteatotic reduction in livers before transplantation.

Prediction factors of postoperative hyperbilirubinemia in living right lobe donor: a single-center analysis of 210 cases

BACKGROUND

Hyperbilirubinemia in living liver donor is very common, but the causes are still unclear.

AIMS

We sought to clarify the risk factors and predictors of nonobstructive hyperbilirubinemia among living donors.

METHODS

We divided 210 consecutive right liver lobe donors into two groups according to the peak total bilirubin postoperatively. We collected data on preoperative, intraoperative, and postoperative biochemical measurements retrospectively, performing multivariate logistic regression analysis adjusting for potential confounders of the risk of hyperbilirubinemia.

RESULTS

There were significant differences between the two groups in donor age, body mass index, operative time, blood loss, macrovescicular steatosis, allogeneic blood transfusion rate, intensive care unit stay, hospital stay and Clavien score after donation (P < .05). Age, graft/donor weight, operative time, and blood loss were significantly associated with the risk of hyperbilirubinemia upon logistic regression analysis.

CONCLUSION

Hyperbilirubinemia, one type of hepatic dysfunction after a living donor procedure, was associated with multiple independent risk factors.

Donor safety in live-related liver transplantation

Living donor liver transplantation (LDLT), since its advent in late 1980's and early 1990's, has rapidly increased especially in countries like Japan, Korea and India where cadaveric programmes are not as well established as in the western world. The main advantage of LDLT is the availability of an organ in the elective setting in the course of a progressive liver disease. This is most applicable in patients with Cirrhosis and Hepatocellular carcinoma. LDLT, from the donor's perspective does carry a risk of not only morbidity but mortality. To date the surgical mortality risk is estimated at 0.1% for left lateral donation and 0.5% for right liver donation. Donor mortality has been reported from various centres in India. There are reports of complications like Hepatic artery thrombosis, portal vein thrombosis and especially biliary leaks and strictures occurring at a significantly increased frequency after living as compared to deceased donor liver transplantation. The key to reduce donor morbidity and mortality is meticulous donor selection and thorough donor work up. In the present study we will analyse the factors that contributed to donor mortality and morbidity and prepare a detailed work up plan, intraoperative and post-operative strategy to reduce donor morbidity and mortality.

Temporal changes in the stiffness of the remnant liver and spleen after donor hepatectomy as assessed by acoustic radiation force impulse: A preliminary study

AIM

  Virtual touch tissue quantification (VTTQ) is an implementation of ultrasound acoustic radiation force impulse imaging that provides numerical measurements of tissue stiffness. We have evaluated the temporal changes of the remnant liver and spleen after living donor hepatectomy with special reference to the differences between right and left liver donation.

METHODS

  Nineteen living donors who received right lobectomy (small remnant liver [SRL] group; n = 7) or extended left and caudate lobectomy (large remnant liver [LRL] group; n = 12) were enrolled. They underwent measurement of liver and spleen VTTQ before and after donor surgery.

RESULTS

  Virtual touch tissue quantification of the remnant liver increased postoperatively until postoperative day (POD) 3-5, and the values in the SRL group were significantly higher than those in the LRL group at POD 3-9. The values of the spleen also increased after donor surgery and the values in the SRL group were significantly higher than those in the LRL group at POD 3-14. A significant positive correlation between postoperative maximum value of VTTQ and postoperative maximum total bilirubin levels was observed. In liver transplant recipients, there was a significant positive correlation between preoperative spleen VTTQ and the corresponding actual portal venous pressure that was measured at the time of transplant surgery.

CONCLUSION

  Stiffness of the remaining liver and spleen in the smaller remnant liver group became harder than that in the larger remnant liver group. Perioperative measurement of liver and spleen VTTQ seems to be a useful means for assessing the physiology of liver regeneration.

Deceleration of regenerative response improves the outcome of rat with massive hepatectomy

Small residual liver volume after massive hepatectomy or partial liver transplantation is a major cause of subsequent liver dysfunction. We hypothesize that the abrupt regenerative response of small remnant liver is responsible for subsequent deleterious outcome. To slow down the regenerative speed, NS-398 (ERK1/2 inhibitor) or PD98059 (selective MEK inhibitor) was administered after 70% or 90% partial hepatectomy (PH). The effects of regenerative speed on liver morphology, portal pressure and survival were assessed. In the 70% PH model, NS-398 treatment suppressed the abrupt replicative response of hepatocytes during the early phase of regeneration, although liver volume on day 7 was not significantly different from that of the control group. Immunohistochemical analysis for CD31 (for sinusoids) and AGp110 (for bile canaliculi) revealed that lobular architectural disturbance was alleviated by NS-398 treatment. In the 90% PH model, administration of NS-398 or PD98059, but not hepatocyte growth factor, significantly enhanced survival. The abrupt regenerative response of small remnant liver is suggested to be responsible for intensive lobular derangement and subsequent liver dysfunction. The suppression of MEK/ERK signaling pathway during the early phase after hepatectomy makes the regenerative response linear, and improves the prognosis for animals bearing a small remnant liver.

Compressive stenosis of the left hepatic vein as a pathogenesis of postresectional liver failure: a case report

Introduction

Postresectional liver failure (PLF) is a devastating and fatal complication of major hepatic resection, and we do not have a full understanding of the pathogenic mechanisms involved. No reliable treatment other than liver transplantation currently exists for PLF.

Case presentation

A 46-year-old Japanese man experienced PLF after an extended right hepatectomy for liver malignancy. Seven months after surgery, the patient's Model for End-Stage Liver Disease (MELD) score had reached 23. Doppler ultrasound study and three-dimensional computed tomography images showed a stenosed left hepatic vein compressed by surrounding hypertrophied hepatic parenchyma. Transluminal balloon angioplasty and stent placement therapy were conducted eight months after surgery. The pressure gradient between the hepatic vein and right atrium decreased from 13 to 3 mmHg after stent placement. Thereafter, the patient recovered.

Conclusion

Hepatic venous compression by surrounding hypertrophied hepatic parenchyma might, at least in part, be associated with the occurrence of PLF. Surgeons should bear this possibility in mind when confronted with cases of PLF, as early diagnosis and stent placement improves patients' chances of recovery.

Strategies for improving the outcomes of small-for-size grafts in adult-to-adult living-donor liver transplantation

Living-donor liver transplantation (LDLT) has been refined and accepted as a valuable treatment for patients with end-stage liver disease in order to overcome the shortage of organs and mortality on the waiting list. However, graft size problems, especially small-for-size (SFS) grafts, remain the greatest limiting factor for the expansion of LDLT, especially in adult-to-adult transplantation. Various attempts have been made to overcome the problems regarding SFS grafts, such as increasing the graft liver volume and/or controlling excessive portal inflow to a small graft, with considerable positive outcomes. Recent innovations in basic studies have also contributed to the treatment of SFS syndrome. Herein, we review the literature and assess our current knowledge of the pathogenesis and treatment strategies for the use of SFS grafts in adult-to-adult LDLT.

Essential pathogenic and metabolic differences in steatosis induced by choline or methione-choline deficient diets in a rat model

BACKGROUND AND AIM

Choline deficient (CD) and methione-choline deficient (MCD) diets are rodent models for steatosis, with potentially dissimilar biochemical backgrounds. The aim of this study was to assess the metabolic and pathological derangements in rats fed CD and MCD diets.

METHODS

Male Wistar rats received CD or MCD diet up to 7 weeks. Nutritional status, liver histopathology, Kupffer cell-mediated inflammation and injury, oxidative stress via thiobarbituric reactive species (TBARS), hepatic and plasma glutathione (GSH) and insulin homeostasis were assessed.

RESULTS

In CD-fed rats, mainly microvesicular steatosis developed with occasional inflammatory cells. In MCD-fed rats, macrovesicular steatosis progressed to steatohepatitis (collagen deposition, activated stellate cells). Hepatic TBARS was increased and GSH decreased in the MCD-fed rats compared to no changes in the CD-fed rats. The CD-fed rats developed obesity, dyslipidemia and insulin resistance, in contrast to undetectable plasma lipids, unaffected insulin homeostasis and loss of body weight in the MCD-fed rats.

CONCLUSIONS

The CD diet induced uncomplicated steatosis as compared to progressive inflammation and fibrinogenesis in the MCD diet. CD and MCD diets represent two pathogenically different models of steatosis. Although equivalence for the outcome of both diets can be found in clinical steatosis, the results of models using these diets should be compared with caution.

Hepatic steatosis is associated with intrahepatic cholestasis and transient hyperbilirubinemia during regeneration after living donor liver transplantation

A clear understanding of the mechanisms in steatotic livers that trigger cholestasis or hyperbilirubinemia after living donor liver transplantation (LDLT) remains elusive. We hypothesized that microarchitectural disturbance might occur within regenerating steatotic livers without impairment of hepatic proliferative activity. Liver biopsy specimens from 67 LDLT recipients taken at the 10th postoperative day were scored for the numbers of portal tracts per area (nPT/A) of liver tissue and for intrahepatic cholestasis, and immunostained by proliferating cell nuclear antigen (PCNA) and Ki-67. The preoperative degree of macrovesicular steatosis (MaS) was independently associated with cholestasis after LDLT (P < 0.001). Serum total bilirubin results on the 1st, 3rd, and 7th days post-LDLT in MaS+ (5-30% of MaS; n = 37) patients were significantly higher than those in MaS- (<5% of MaS; n = 30) patients (P = 0.030, 0.042, and 0.019, respectively). Mean numbers of positively stained hepatocytes were 53.1 +/- 12.0 in patients with MaS and 48.0 +/- 17.1 in those without MaS by PCNA (P = 0.390), and 24.4 +/- 10.5 and 24.0 +/- 14.0 by Ki-67 (P = 0.940). However, a significant negative correlation was found between the degree of MaS and nPT/A (P = 0.013), and nPT/A was correlated with the grade of histological cholestasis (r = 0.350, P = 0.039). Intrahepatic cholestasis and hyperbilirubinemia after LDLT could be caused by scanty morphologic change of portal tract during steatotic liver regeneration.

A remarkable permeability of canalicular tight junctions might facilitate retrograde, non-viral gene delivery to the liver via the bile duct

AIMS

To establish the extent of retrograde bile duct infusion at an ultrastructural level, as a preliminary step before evaluating the efficacy of gene delivery to the rat liver via a branch of the bile duct.

METHODS

The extent of retrograde infusion into the biliary tree was established by light and electron microscopy, following infusion of 10 nm gold particles into the right lateral lobe. Canalicular permeability was further assessed by the infusion of a 67 kDa protein. For gene delivery, both naked DNA and a synthetic peptide vector system were evaluated. Because canalicular tight junction permeability can be compromised in damaged livers, both normal rats and rats recovering from the hepatotoxin D-galactosamine were studied.

RESULTS

The gold particles penetrated the peripheral one third of the hepatic lobules and, surprisingly, reached the space of Disse in normal rats. Equally surprisingly, blood levels of a 67 kDa protein were identical after bile duct infusion and portal vein injection. Gene delivery with peptide/DNA complexes was much more effective in rats treated with D-galactosamine. However, gene delivery with naked DNA was equally effective in normal and damaged livers. Localisation of gene expression showed a scattering of positive hepatocytes restricted to the right lateral lobe.

CONCLUSIONS

Retrograde infusion into the bile duct advances well into the hepatic lobule and reveals a remarkable permeability of the canalicular or cholangiole tight junctions in normal rats. It is an effective approach for delivering genes to a small population (approximately 1%) of hepatocytes.

Living-donor liver transplantation: present status and future perspective

About 15 years have passed since the first liver transplant from a living donor (living donor liver transplantation: LDLT), and the status of the procedure has since been established as a standard cure for end-stage liver disease in Japan where liver transplantation (LTx) from deceased donors has not yet been accepted. However, the following problems are surfacing with the increase in the number of LDLTs between adults: graft size mismatching, an ABO blood-type incompatible transplantation, the expansion of LDLT indication to hepatocellular carcinoma (HCC), the relapse of hepatitis C after LDLT, marginal donors, and the freedom from immunosuppressive treatment. In this article we outline the present conditions of these problems and the future view of the LDLT.