Human urokinase-type plasminogen activator gene-modified bone marrow-derived mesenchymal stem cells attenuate liver fibrosis in rats by down-regulating the Wnt signaling pathway

AIM: To evaluate the therapeutic effects of bone marrow-derived mesenchymal stem cells (BMSCs) with human urokinase-type plasminogen activator (uPA) on liver fibrosis, and to investigate the mechanism of gene therapy.

METHODS: BMSCs transfected with adenovirus-mediated human urokinase plasminogen activator (Ad-uPA) were transplanted into rats with CCl₄-induced liver fibrosis. All rats were sacrificed after 8 wk, and their serum and liver tissue were collected for biochemical, histopathologic, and molecular analyzes. The degree of liver fibrosis was assessed by hematoxylin and eosin or Masson’s staining. Western blot and quantitative reverse transcription-polymerase chain reaction were used to determine protein and mRNA expression levels.

RESULTS: Serum levels of alanine aminotransferase, aminotransferase, total bilirubin, hyaluronic acid, laminin, and procollagen type III were markedly decreased, whereas the levels of serum albumin were increased by uPA gene modified BMSCs treatment. Histopathology revealed that chronic CCl4-treatment resulted in significant fibrosis while uPA gene modified BMSCs treatment significantly reversed fibrosis. By quantitatively analysing the fibrosis area of liver tissue using Masson staining in different groups of animals, we found that model animals with CCl₄-induced liver fibrosis had the largest fibrotic area (16.69% ± 1.30%), while fibrotic area was significantly decreased by BMSCs treatment (12.38% ± 2.27%) and was further reduced by uPA-BMSCs treatment (8.31% ± 1.21%). Both protein and mRNA expression of β-catenin, Wnt4 and Wnt5a was down-regulated in liver tissues following uPA gene modified BMSCs treatment when compared with the model animals.

CONCLUSION: Transplantation of uPA gene modified BMSCs suppressed liver fibrosis and ameliorated liver function and may be a new approach to treating liver fibrosis. Furthermore, treatment with uPA gene modified BMSCs also resulted in a decrease in expression of molecules of the Wnt signaling pathway.

[Prolonged angiotensin-(1-7) infusion inhibits hepatic fibrosis in rats with bile duct ligation]

OBJECTIVE

To observe the inhibitory effect of angiotensin-(1-7) on liver fibrosis induced by bile duct ligation in rats.

METHODS

Eighteen Wistar rats were randomized into 3 groups and subject to sham operation, bile duct ligation (BDL), or BDL with angiotensin-(1-7) treatment. An osmotic minipump was implanted intraperitoneally for administration of saline in the sham-operated and BDL groups and angiotensin-(1-7) (25 µg·kg(-1)·h(-1)) in angiotensin-(1-7) treatment group. After a 4-week treatments, the fibrosis score, Masson staining, and hydroxyproline assay were used to evaluate the level of liver fibrosis in the rats, and immunohistochemistry was used to detect expression of α-smooth muscle actin (α-SMA) in the liver tissue.

RESULTS

Compared with BDL group, a 4-week treatment with angiotensin-(1-7) following BDL significantly reduced the fibrosis score (2.33±0.52 vs 5.17±0.75), hydroxyproline content (0.36±0.03 vs 0.52±0.04) and α-SMA expression (54.11±17.55 vs 191.84±31.72) in the liver tissue of the rats (P<0.01).

CONCLUSION

Prolonged infusion of angiotensin-(1-7) inhibit the formation of hepatic fibrosis in rats following bile duct ligation.

Modulation of AP-endonuclease1 levels associated with hepatic cirrhosis in rat model treated with human umbilical cord blood mononuclear stem cells

Oxidative stress in liver cells may contribute to the etiology of hepatic diseases, as in liver cirrhosis. AP-Endonuclease1 (APE1/Ref-1) is essential for cell protection toward oxidative stress by acting as a transcriptional regulator of pro-survival genes and as a redox sensitive protein. The aim of this study was to critically analyze the various parameters governing the success of human umbilical cord blood mononuclear stem cell-based (MNCs) therapy without the use of an immunosuppressant and to investigate for the first time the expression of APE1 during thioacetamide (TAA)-induced cirrhosis and MNCs therapy in a rat model. Umbilical cord blood samples from full-term deliveries were collected. Lethal fulminant hepatic cirrhosis in rats was induced by intraperitoneal injection of thio-acetamide. MNCs were then intrahepatically transplanted. We measured APE1 expression at mRNA and protein levels, mRNA expression of TGF-β, α-SMA, STAP, CTGF, MMP-9 and TIMP-1 in a follow up study. Histopathological and immunohistochemical analyses were performed 10 weeks after intrahepatic injection of the cells. Transdifferentiated cells could be efficiently stained with antihuman hepatocytes. Interestingly, human hepatocyte-specific markers, human albumin, cytokeratin-18 and cytokeratin-19 mRNAs were detected in rat liver after 10 days of MNCs infusion. MNC transplanted by intrahepatic route, could engraft recipient liver, differentiated into functional hepatocytes, and rescued liver failure. Moreover up regulation of APE1 expression confirmed by marked immunohistochemical staining may be involved in MNCs-induced hepatocytes regeneration suggesting that maintaining high level of APE1 has protective effect as pro-survival signal.

[Antioxidant system activation in rats with experimental cirrhosis after injection of cryopreserved fetal liver cells]

The possibility to recover the antioxidant system in rats with experimental liver cirrhosis (LC) after allo- and xenotransplantation of cryopreserved fetal liver cells (FLC) was investigated. It was shown that the content of lipid peroxidation products in the blood serum of animals with LC four weeks after FLC transplantation decreased significantly as compared to control group. Such changes were accompanied by a significant increase of catalase (CAT), glutathione reductase (GR), Se-dependent glutathione peroxidase (GP) activity in the liver and total anti-oxidative activity (AOA) of blood. Obtained results demonstrate that the main direction of FLC effects in animals with LC agree with that we observed previously in other experimental models (partial hepatectomy, chronic alcohol poisoning and hypercholesterolemia). In conclusion, cell therapy may be considered as the universal method for correction of disorders in regulation of free-radical processes in various experimental pathologies.

[Cryosurgery in diffuse hepatic diseases]

Comparative studying, using histological and biomicroscopic methods, of the dosed cryohepatodestruction (CHD), periarterial cryodenervation of hepatic artery (CDHA) and their concomitant application influence on the dynamics of hepatic restoration processes in experimental cirrhosis was performed. The investigations were done on 215 male rats owing body mass 200-280 g in a not changed and pathologically changed liver. There was shown, that CDHA promotes changes in hepatic tissue microhemocirculation, as well as the enhancement of the sinusoidal vessels diameter and relative square of vascular bed. CHD stimulates the reparative processes course in a pathologically changed organ. There was established, that while simultaneous application of two cryosurgical methods, the velocity and grade of restoration processes in cirrhotically-changed liver are enhanced in comparison with such indices changes while separate usage of these two methods.

[Effects of gene-transfected bone marrow-derived liver stem cell transplantation on accumulation of extracellular matrix in rats with liver fibrosis]

OBJECTIVE

To explore the effects of urokinase-type plasminogen activator (uPA) gene-modified bone marrow-derived stem cell (BDLSC) transplantation on accumulation of extracellular matrix (ECM) in hepatic tissue in liver fibrosis.

METHODS

BDLSCs obtained from 10 male Fisher344 rats were transfected by adenovirus-mediated human uPA (AduPA) in vitro. Twenty-seven female rats were randomly divided into 3 equal groups to undergo subcutaneous injection of carbon tetrachloride to establish liver fibrosis models and then randomly divided into 3 equal groups: model group injected with normal saline via caudal vein, BDLSC group injected with 2 x 10(6) BDLSCs via caudal vein, and BDLSC-uPA group injected with 2 x 10(6) AduPA-transfected BDLSCs. Eight weeks later the serum levels of alanine transaminase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), albumin (ALB), and ECM levels, i.e., hyaluronic acid, laminin (LN), and procollagen III (PC III), were detected. Then the rats were killed with their livers taken out. The hydroxyproline (Hyp) content of the liver was detected by alkaline hydrolysis. RT-PCR was used to examine the expression of collagen I and III (COLI and COLIII), matrix metalloproteinases-2, 3, and 9 (MMP-2, 3, and 9), and tissue inhibitor of metalloproteinase-1 and 2 (TIMP-1 and 2).

RESULTS

Compared with those of the model group the levels of ALT, AST, and TBIL of the BDLSC-uPA group were all significantly lower, and the ALB level was higher (all P < 0.05). The ECM levels of BDLSC-uPA group were all significantly lower than those of the model group or BDLSC group too (all P < 0.05). Hyp content of the liver decreased dramatically. The mRNA expression levels of COLI and COLIII of the liver of the BDLSC-uPA group were significantly lower (38.9 +/- 2.7, 8.5 +/- 1.6), and the mRNA expression levels of MMP-2, -3, and MMP-9 mRNA (157.5 +/- 32.6, 105.5 +/- 14.6, 187.5 +/- 22.8) were significantly higher than those of the model group or BDLSC group (all P < 0.05), but no significant differences were observed in the mRNA expression of TIMP-1 and 2 mRNA between the 3 groups (all P > 0.05).

CONCLUSION

uPA gene-modified BDLSC transplantation improves the liver function and suppresses the hepatic fibrosis in liver cirrhosis through up-regulating the expression of MMPs and promoting the degradation of ECM.

Functional hepatic recovery after xenotransplantation of cryopreserved fetal liver cells or soluble cell-factor administration in a cirrhotic rat model: are viable cells necessary?

BACKGROUND AND AIM

Chronic liver failure results in the decrease of the number of functioning hepatocytes. It dictates the necessity of using exogenous viable cells or/and agents that can stimulate hepatic regenerative processes. Fetal liver contains both hepatic and hematopoietic stem cells with high proliferative potential, which may replace damaged cells. Also, immature cells produce fetal-specific factors which may support the injured liver. Our aim was to test the ability of human fetal liver cells and cell-free fetal-specific factors of non-hepatic origin to stimulate recovery processes in an experimental model of carbon tetrachloride-induced cirrhosis in rats.

METHODS

Cirrhotic rats were intrasplenically injected with fetal liver cells (1 x 10(7) cells/0.3 mL medium) or cell-free fetal-specific factors (0.3 mL/1 mg protein). Control groups received medium alone. Serum indexes, hepatic functions, and morphology were evaluated for 15 days.

RESULT

Human fetal liver cell transplantation was shown to abrogate the mortality of cirrhotic animals, to improve serum markers, and to restore liver mitochondrial function and detoxification. Morphological patterns of liver recovery were observed by histology. In comparison, an injection of fetal-specific factors produced similar functional recovery, whilst a more limited liver regeneration was observed by histology.

CONCLUSIONS

The positive effects of fetal liver cell and cell-free fetal-specific factors in experimental cirrhosis may result from the presence of stage-specific factors activating hepatocellular repair.

Bone marrow cell transplant does not prevent or reverse murine liver cirrhosis

We tested the effect of bone marrow cell (BMC) transplantation in either preventing or reversing cirrhosis on an experimental model of chronic liver disease. Female Wistar rats were fed a liquid alcohol diet and received intraperitoneal injections of carbon tetrachloride (CCl4) over 15 weeks. Ten animals (cell-treated group) received five injections of BMCs during the cirrhosis induction protocol (on the 4th, 6th, 8th, 10th, and 12th weeks) and four animals received the cells after liver injury was established through tail vein. Nine animals (nontreated group) were submitted to the previously described protocols; however, they received vehicle injections. Analyses were performed to verify whether the infusion of cells was effective in preventing the development of cirrhosis in our model of induction, and if the cells could reverse cirrhosis once it was established. Hepatic architecture and fibrotic septa were analyzed in liver slices stained with hematoxilin & eosin and Sirius red, respectively. Fibrosis quantification was measured by Sirius red histomorphometry. Indirect immunofluorescence was performed to detect the amount of tissue transglutaminase 2. Blood analyses were performed to assess liver injury and function by the assessment of alanine aminotransferase and albumin. Ultrasound was performed to analyze the portal vein caliber and presence of ascitis. Cirrhosis features (regenerative nodules and fibrous septa) were observed in histopathology after 15 weeks of continuous hepatic injury in nontreated and cell-treated groups. Collagen content, immunofluorescence analysis, and biochemical and ultrasound parameters were similar in nontreated and cell-treated groups; however, both groups showed significant differences compared to a normal control group. Cell infusions with bone marrow-derived cells seem to be ineffective in improving morphofunctional parameters of the liver when applied to chronic cases either during or after establishment of the hepatic lesion.

[Three-dimensional assessment of the remnant hepatic function following surgery using single photon emission computed tomography in an animal model]

OBJECTIVE

The predictive value of postoperative hepatic function evaluated by liver functional imaging combined with single photon emission computed tomography (SPECT) technique was appraised in the present study.

METHODS

Twenty New Zealand white rabbits were divided randomly into two groups, including the Hepatic Fibrosis with Carcinoma Group (FC-Group, n = 10) and the Control Group (C-Group, n = 10). All the rabbits underwent the resection of outer-right lobe of the liver. The whole hepatic function indexes, such as HCI(5), HLI(5) and Ex(15), and the hepatic function remnant indexes, including HCI(5P), HLI(5P) and Ex(15P), were calculated by 99mTc-EHIDA liver imaging.

RESULTS

Ex(15) of FC-Group was lower than that of C-Group (P < 0.05). HCI(5) and HLI(5) of FC-Group had the trends to increase compared with the C-Group. Ex(15) was positively correlated with ALB, and negatively correlated with TBil and GGT (P < 0.05). HCI(5) had a positive correlation with CHE (P < 0.05), while HLI(5) had a negative correlation with A/G (P < 0.05). HLI(5P) had the negative correlation with postoperative A/G (P < 0.05), and Ex(15P) had the negative correlation with postoperative TBil and GGT (P < 0.05).

CONCLUSIONS

This study has established a method of 3-D liver function evaluation system on an animal model. Among the indexes, Ex(15) can exactly represent the whole liver function while Ex(15P) and HLI(5P) can predict the liver function after the liver resection. The results may help the future clinical use of this technique to evaluate the risk of operation.

Differential regulation of protein S expression in hepatocytes and sinusoidal endothelial cells in rats with cirrhosis

BACKGROUND

Liver dysfunction caused by intrasinusoidal microthrombi is frequently observed in patients with cirrhosis after hepatectomy, but the mechanistic pathway remains unknown.

OBJECTIVE

In the present study, we evaluated the expression of protein S (PS) in hepatocytes and sinusoidal endothelial cells (SECs) from rats with dimethylnitrosoamine-induced cirrhosis before and after hepatectomy.

RESULTS

The plasma level of PS antigen was significantly decreased in cirrhotic rats as compared to control rats treated with vehicle. PS expression was significantly decreased in hepatocytes isolated from cirrhotic rats as compared to controls. In contrast, PS expression was significantly increased in SECs isolated from rats with cirrhosis as compared to controls. Interleukin-6 (IL-6) upregulated the expression of PS in hepatocytes, and tumor necrosis factor-alpha (TNF-alpha) decreased its expression in SECs from both cirrhotic and normal rats. The production of IL-6 and TNF-alpha by Kupffer cells and SECs was decreased in rats with cirrhosis as compared to controls. After hepatectomy, microthrombus formation was markedly enhanced in sinusoids from rats with cirrhosis, and the plasma levels of IL-6 and TNF-alpha were significantly increased in rats with cirrhosis as compared to controls. Furthermore, PS production in SECs was decreased, whereas that in hepatocytes was significantly increased in cirrhotic rats as compared to controls.

CONCLUSIONS

These findings suggest that PS expression is differently regulated in hepatocytes and SECs of rats with cirrhosis before and after hepatectomy, that the expression of PS is regulated by locally released inflammatory cytokines, and that decreased expression of PS in SECs may cause liver microthrombus formation, which is frequently observed in patients with cirrhosis after hepatectomy.

Administration of fibroblast growth factor 2 in combination with bone marrow transplantation synergistically improves carbon-tetrachloride-induced liver fibrosis in mice

We previously reported that fibroblast growth factor 2 (FGF2) facilitated the differentiation of transplanted bone marrow cells (BMCs) into hepatocytes. Our earlier study also demonstrated that administration of FGF2 in combination with bone marrow transplantation (BMT) synergistically activated tumor necrosis factor-alpha signaling and significantly improved liver function and prognosis more than BMT alone. However, the way that it affected the extracellular matrix remained unclear. Here, we investigated the effect of FGF2 treatment together with BMT on liver fibrosis in mice treated with carbon tetrachloride (CCl(4)). Transplantation of BMCs and concurrent treatment with FGF2 caused a statistically significant reduction in CCl(4)-induced liver fibrosis that was accompanied by strong expression of matrix metalloproteinase 9 as compared with FGF2-only treatment or BMT alone. Moreover, in this process, the proliferation of bone-marrow-derived cells was accelerated without causing apoptosis. Thus, the administration of FGF2 in combination with BMT synergistically improves CCl(4)-induced liver fibrosis in mice. This treatment has the potential of being an effective therapy for patients with liver cirrhosis.

Combination gene therapy of HGF and truncated type II TGF-beta receptor for rat liver cirrhosis after partial hepatectomy

BACKGROUND

In a cirrhotic liver, the regenerative ability and specific functions are impaired; a hepatic resection increases the possibility of postoperative liver failure. Hepatocyte growth factor (HGF) stimulates liver regeneration, accelerates restoration of hepatic function, and improves fibrosis. A truncated type II transforming growth factor-beta receptor (TbetaTR), which specifically inhibits TGF-beta signaling as a dominant-negative receptor, appears to prevent the progression of liver fibrosis. We demonstrated the therapeutic efficacy of adenovirus-mediated HGF and TbetaTR gene transduction after partial hepatectomy for liver cirrhosis.

METHODS

Rats were treated with dimethylnitrosamine for 3 weeks, and they all had severe cirrhosis. After partial hepatectomy (10%), we injected adenovirus expressing bacterial beta-galactosidase (AdLacZ), adenovirus expressing a truncated type II TGF-beta receptor (AdTbetaTR), adenovirus expressing hepatocyte growth factor (AdHGF), or AdTbetaTR + AdHGF into the portal vein, which was followed by an additional 2-week dimethylnitrosamine treatment.

RESULTS

On histologic examination, fibrotic tissue had decreased in the livers of the AdTbetaTR + AdHGF-treated rats compared with rats that were treated by AdLacZ, AdTbetaTR alone, and AdHGF alone. Liver function, which included serum levels of alanine aminotransferase, improved significantly in AdTbetaTR + AdHGF-treated rats compared with all other groups. The number of hepatocytes that were positive for proliferating-cell nuclear antigen was greater (P < .05) in AdHGF alone and AdTbetaTR + AdHGF-treated rat livers than in AdLacZ- and AdTbetaTR-treated rats. All AdTbetaTR + AdHGF-treated rats survived >60 days, and AdTbetaTR + AdHGF treatment markedly improved the survival rate after a partial hepatectomy.

CONCLUSION

Our results suggest that the combination of HGF and TbetaTR gene therapy may increase the possibility of hepatectomy in a cirrhotic liver by improving fibrosis, hepatic function, and hepatocyte regeneration.

Safety limit of large-volume hepatic radiofrequency ablation in a rat model

BACKGROUND

Large-volume hepatic radiofrequency ablation (RFA) has been used to treat large liver tumors, but its safety limit is unknown. This study aimed to investigate the possible systemic responses of large-volume hepatic RFA and to estimate its safety limit in normal and cirrhotic rats.

HYPOTHESIS

Large-volume hepatic RFA causes a significant systemic inflammatory reaction.

DESIGN

Experimental study.

SETTING

University teaching hospital.

INTERVENTION

Using the Cool-tip RF System (Radionics, Burlington, Mass), RFA was performed for different percentages of the liver volume by weight in normal and cirrhotic Sprague-Dawley rats.

MAIN OUTCOME MEASURES

Changes in concentrations of serum inflammatory markers (tumor necrosis factor alpha [TNF-alpha] and interleukin [IL] 6), functions of various end organs, and survival rates were assessed.

RESULTS

In the normal liver groups, the concentrations of TNF-alpha and IL-6 were significantly elevated in the early postoperative period when 50% (mean +/- SD TNF-alpha concentration, 130.3 +/- 15.6 pg/mL; mean +/- SD IL-6 concentration, 163.2 +/- 12.2 pg/mL) and 60% (mean +/- SD TNF-alpha concentration, 145.7 +/- 13.0 pg/mL; mean +/- SD IL-6 concentration, 180.8 +/- 11.0 pg/mL) of the liver volume were ablated compared with the control group (mean +/- SD TNF-alpha concentration, 30.4 +/- 9.9 pg/mL, P<.001; mean +/- SD IL-6 concentration, 28.4 +/- 6.7 pg/mL, P<.001). The concentrations of TNF-alpha and IL-6 in other groups remained similar to those in the control group. Thrombocytopenia, prolonged clotting time, and interstitial pneumonitis occurred when 50% and 60% of the liver volume were ablated. The 4-week survival rates were 100%, 60%, and 0% when 40%, 50%, and 60%, respectively, of the liver volume were ablated. Similar systemic inflammatory responses and poor survival rates were observed among the cirrhotic liver groups when 30% and 40% of the liver volume were ablated.

CONCLUSIONS

The normal rats can tolerate RFA of 40% of the liver volume with minimal morbidity and no mortality whereas the cirrhotic rats can only tolerate 20% of the ablated liver volume. Beyond that limit, RFA would cause significant systemic inflammatory responses and poor survival.

Rapamycin attenuates liver graft injury in cirrhotic recipient--the significance of down-regulation of Rho-ROCK-VEGF pathway

To investigate whether rapamycin could attenuate hepatic I/R injury in a cirrhotic rat liver transplantation model, we applied a rat orthotopic liver transplantation model using 100% or 50% of liver grafts and cirrhotic recipients. Rapamycin was given (0.2 mg/kg, i.v.) at 30 min before graft harvesting in the donor and 24 h before operation, 30 min before total hepatectomy and immediately after reperfusion in the recipient. Rapamycin significantly improved small-for-size graft survival from 8.3% (1/12) to 66.7% (8/12) (p = 0.027). It also increased 7-day survival rates of whole grafts (58.3%[7/12] vs. 83.3%[10/12], p = 0.371). Activation of hepatic stellate cells was mainly found in small-for-size grafts during the first 7 days after liver transplantation. Rapamycin suppressed expression of smooth muscle actin, which is a marker of hepatic stellate cell activation, especially in small-for-size grafts. Intragraft protein expression and mRNA levels of vascular endothelial growth factor (VEGF) were down-regulated by rapamycin at 48 h both in whole and small-for-size grafts. Consistently, mRNA levels and protein expression of Rho and ROCK I were decreased by rapamycin during the 48 h after liver transplantation. In conclusion, rapamycin attenuated graft injury in a cirrhotic rat liver transplantation model by suppression of hepatic stellate cell activation, related to down-regulation of Rho-ROCK-VEGF pathway.

Availability of bone marrow stromal cells in three-dimensional coculture with hepatocytes and transplantation into liver-damaged mice

Rat bone marrow stromal cells (BMSCs) were cultured in porous hydroxyapatite (HA) disks for 2 weeks to form a cell layer on the surface. Freshly isolated hepatocytes were then inoculated into both BMSC-cultured and non-treated HA disks. Hepatocytes cocultured with BMSCs secreted significantly more albumin than those in monoculture in vitro. The cell-packed HA disks were implanted into the peritoneal cavity of Nagase analbuminemia rats (NARs), and 4 weeks later, blood samples were collected to measure the albumin concentration. The cotransplantation of BMSCs with hepatocytes significantly increased the serum albumin concentration in NARs. The HA disks coculturing mice hepatocytes and BMSCs were also implanted into mice, in which liver damage had been induced using carbon tetrachloride and phenobarbital. The decreased serum albumin level in liver-damaged mice was completely recovered by the transplantation of hepatocytes and BMSCs. The serum level of IL-6 in liver-damaged mice was also increased by the cotransplantation of BMSCs and hepatocytes. Thus, the transplantation of BMSCs appears to have a systemic effect on recipients through the increase in the serum cytokine level as well as a local effect on cotransplanted hepatocytes.

Functional restoration of cirrhotic liver after partial hepatectomy in the rat

BACKGROUND/AIMS

Although cirrhosis is the terminal stage of various liver diseases, thanks to recent advances one might eliminate some causes of liver damage. Liver has a potent regeneration capacity. It is important to evaluate the regenerating cirrhotic liver after partial hepatectomy, morphologically and functionally, in the long term.

METHODOLOGY

We evaluated the functional capacity of the rat liver rendered cirrhotic by orally administered thioacetamide, and examined the correlation between morphological and functional restoration after 2/3 hepatectomy in comparison with hepatectomized normal rats and sham-operated cirrhotic rats. Morphological restoration was evaluated by remnant liver weight, proliferating cell nuclear antigen labeling index, and fibrosis ratio. Functional restoration was evaluated by the indocyanine green disappearance rate and aminopyrine clearance.

RESULTS

Cirrhotic rats were functionally deteriorated in comparison with the normal rats. Morphological restoration in cirrhotic rats was delayed in comparison with normal rats. Functional restoration after 2/3 hepatectomy was advanced in comparison with morphological restoration. In comparison with sham-operated cirrhotic rats, functional restoration of the cirrhotic liver was accelerated by partial hepatectomy.

CONCLUSIONS

In cirrhotic rats, functional restoration of the liver after 2/3 hepatectomy was advanced in comparison with morphological restoration. Partial hepatectomy seemed to promote functional restoration of the cirrhotic liver.

[Effects of portaazygous disconnection, portocaval shunt and selective shunts on experimental rat liver cirrhosis]

OBJECTIVE

To evaluate the effects of portaazygous disconnection (PAD), portacaval shunt (PCS) and distal splenocaval shunt (DSCS) on the portosytemic shunting (PSS), hepatic function (HF), hepatic mitochondrial respiratory function (HMRF), oral glucose tolerance test (OGTT) and arterial ketone body ratio (KBR) in order to provide a sound basis for selecting suitable operations for patients.

METHODS

Using a cirrhotic portal hypertensive model induced by CCl4/ethanol in Wistar rats, the PSS, HF, HMRF, OGTT and KBR were determined three weeks after PCS, DSCS and PAD.

RESULTS

It was revealed that: (1) In the cirrhotic portal hypertension rats, the PSS increased significantly, HMRF and hepatic reserve function (HRF) decreased significantly when compared with the control rats. (2) At the time of first postoperative week, the mean blood glucose value in the 120-minute OGTT in each PAD, PCS and DSCS groups had significant differences compared with the cirrhotic control group. But during the second and third postoperative weeks, the mean blood glucose values in the 120-minute OGTT in both PAD and DSCS groups had no significant differences compared with the cirrhotic control group except for the PCS group. The values of KBR in the three operative groups decreased significantly compared with the cirrhotic control group during the two postoperative weeks. In the third postoperative week, only the values of KBR in the PCS group had a significant difference compared with the cirrhotic control group. (3) After PCS, the PSS was further increased; HF and HMRF were significantly decreased. Little improvement was found in the third postoperative week. (4) After DSCS and PAD, the above mentioned indices were less influenced, and they were restored more quickly than those in the PCS group.

CONCLUSION

We found that PAD and DSCS are more desirable than PCS.

[Cellular mechanisms of cirrhotic rat liver regeneration. II. Proliferation, polyploidization and hypertrophy after partial hepatectomy]

Using cytofluorimetry and absorptional cytophotometry, hepatocyte DNA and total protein contents were measured in intact and cirrhotic rats in 1, 3 and 6 months after partial hepatectomy (PH). It has been found that within one month of intact rat liver regeneration the level of hepatocyte ploidy rised by 25% to remain elevated for the next 6 months. This was due mainly to reducing the number of cells with diploid nuclei (2c 2-fold, 2c x 2 - 6.6-fold) and to rising the number of octaploid hepatocytes. In cirrhotic animals the ploidy level in hepatocytes increased in 3 months after PH, and decreased by 15% in 6 months. The number of hepatocytes with diploid nuclei (2c and 2c x 2) increased within 3-6 months in both control and cirrhotic rats. The protein content per diploid hepatocyte rised by 30% within 3-6 months of liver regeneration after PH. Special calculations have shown that within 3 months after PH the increase in the liver mass of control and cirrhotic rats was due completely to hepatocyte DNA synthesis, i. e. proliferation and polyploidization. Within the next 3 months of liver regeneration after PH, the contribution of polyploidization to liver mass increase was negative because of depolyploidization of liver parenchyma cell population. At this time hypertrophy was the main process determining the liver mass increase.

Role of intrasplenic hepatocyte transplantation in improving survival and liver regeneration after hepatic resection in cirrhotic rats

We studied the effect of preoperative hepatocyte transplantation on the prevention of liver failure in cirrhotic rats after hepatic resection. Two groups of Lewis rats were rendered cirrhotic by i.p. injection of 1% dimethylnitrosamine and were subjected to 33% hepatectomy. Two days before the resection, 36 rats in group I received intrasplenic hepatocyte transplantation, and 25 rats in group II were given intrasplenic injection of normal saline as a control. By the end of the third postoperative day, the rats in group I had better survival and a better biochemical profile than those in group II. The liver growth rate and the labeling index of proliferating cell nuclear antigen (PCNA-LI) showed a steady rise in group I. Compared with group II, group I had a significantly lower transforming growth factor (TGF-beta1) level (p < 0.05). We conclude that preoperative intrasplenic hepatocyte transplantation improves survival and facilitates regeneration in cirrhotic rats after hepatic resection.

Treatment of cirrhosis and liver failure in rats by hepatocyte xenotransplantation

BACKGROUND & AIMS

Hepatocyte transplantation has been proposed as an alternative to liver transplantation for the treatment of hepatic failure. A major limitation to this form of therapy is the availability of human livers as a source of hepatocytes. The use of porcine hepatocytes might address this problem; however, xenogeneic hepatocytes are thought to be functionally incompatible across species and susceptible to irreversible rejection.

METHODS

Liver cirrhosis was induced with phenobarbital and carbon tetrachloride. Only rats with decompensated liver failure that did not correct 4 weeks after the discontinuation of carbon tetrachloride were subjected to intrasplenic rat or porcine hepatocyte transplantation. The immunologic integrity of cirrhotic rats was assessed by allogeneic skin grafting, and the immune response to transplanted porcine hepatocytes was assessed by enzyme-linked immunosorbent assay.

RESULTS

Porcine hepatocytes restored metabolic function and prolonged the survival of cirrhotic rats, as well as rat hepatocytes. Cirrhotic rats retained the ability to reject allogeneic skin grafts and showed an immune response to the engrafted hepatocytes. Despite this, survival of transplanted porcine hepatocytes was accepted in cirrhotic rats for a period of weeks without immunosuppression. Conventional immunosuppression with FK506 allowed successful retransplantation with hepatocytes from a second porcine donor.

CONCLUSIONS

Hepatocytes transplanted between widely divergent species can function to correct liver failure in cirrhotic rats and prolong their survival. Conventional immunosuppression allows long-term functioning of xenogeneic hepatocyte retransplants and suggests that hepatocyte xenotransplantation might be useful as a bridge to liver transplantation and could potentially provide long-term hepatic support.

Changes in serum hyaluronic acid levels and expression of CD44 and CD44 mRNA in hepatic sinusoidal endothelial cells after major hepatectomy in cirrhotic rats

Serum hyaluronic acid (HA) is widely distributed in connective tissues, and the majority of circulating HA is degraded by hepatic sinusoidal endothelial cells (SECs) via a receptor recycling pathway. Our previous clinical study revealed that monitoring serum HA levels after hepatectomy is useful in predicting the development of liver failure. In the present study, to determine the mechanism of the high HA levels after hepatectomy, especially in patients with liver cirrhosis, expression of the major HA receptor, CD44, and its mRNA was investigated in SECs isolated from rats with thioacetamide-induced liver cirrhosis subjected to 70% hepatectomy (group I) and from rats with a normal liver that were subjected to 70% hepatectomy (group II). The 48-hour postoperative survival rate in group I (13.3%) was significantly lower than in group II (100%). In group II, the expression of CD44 mRNA had increased significantly at 6 hours after hepatectomy, and this was followed by progressive increases in expression of CD44, indicating activation of SEC function. The increased serum HA levels after hepatectomy in group II became normal as CD44 expression increased. By contrast, the expression of CD44 and CD44 mRNA in group I was markedly attenuated after hepatectomy. The very low CD44 expression was followed by a significant and sustained increase in serum HA levels, indicating functional failure of the SECs. These results suggest that the significantly impaired functional reserve of SECs in liver cirrhosis is associated with increased mortality after 70% hepatectomy.

Safe upper limit of intermittent hepatic inflow occlusion for liver resection in cirrhotic rats

AIM: To evaluate the effects of varying ischemic durations on cirrhotic liver and to determine the safe upper limit of repeated intermittent hepatic inflow occlusion.

METHODS: Hepatic ischemia in cirrhotic rats was induced by clamping the common pedicle of left and median lobes after non-ischemic lobes resection. The cirrhotic rats were divided into six groups according to the duration and form of vascular clamping: sham occlusion (SO), intermittent occlusion for 10 (IO-10), 15 (IO-15), 20 (IO-20) and 30 (IO-30) minutes with 5 minutes of reflow and continuous occlusion for 60 minutes (CO-60). All animals received a total duration of 60 minutes of hepatic inflow occlusion. Liver viability was investigated in relation of hepatic adenylate energy charge (EC). Triphenyltetrazollum chloride (TTC) reduction activities were assayed to qualitatively evaluate the degree of irreversible hepatocellular injury. The biochemical and morphological changes were also assessed and a 7-day mortality was observed.

RESULTS: At 60 min after reperfusion following a total of 60 min of hepatic inflow occlusion, EC values in IO-10 (0.749 ± 0.012) and IO-15 (0.699 ± 0.002) groups were rapidly restored to that in SO group (0.748 ± 0.016), TTC reduction activities remained in high levels (0.144 ± 0.002 mg/mg protein, 0.139 ± 0.003 mg/mg protein and 0.121 ± 0.003 mg/mg protein in SO, IO-10 and IO-15 groups, respectively). But in IO-20 and IO-30 groups, EC levels were partly restored (0.457 ± 0.023 and 0.534 ± 0.027) accompanying with a significantly decreased TTC reduction activities (0.070 ± 0.005 mg/mg protein and 0.061 ± 0.003 mg/mg protein). No recovery in EC values (0.228 ± 0.004) and a progressive decrease in TTC reduction activities (0.033 ± 0.002 mg/mg protein) were shown in CO-60 group. Although not significantly different, the activities of the serum aspartate aminotransferase (AST) on the third postoperative day (POD₃) and P OD₇ and of the serum alanine aminotransferase (ALT) on POD₃ in CO-60 group remained higher than that in intermittent occlusion groups. Moreover, a 60% animal mortality rate and more severe morphological alterations were also shown in CO-60 group.

CONCLUSION: Hepatic inflow occlusion during 60 min for liver resection in cirrhotic rats resulted in less hepatocellular injury when occlusion was intermittent rather than continuous. Each period of 15 minutes was the safe upper limit of repeated intermittent vascular occlusion that the cirrhotic liver could tolerate without undergoing irreversible hepatocellular injury.

[Surgical correction of blood and lymph circulation in liver cirrhosis]

After modeling cirrhosis of the liver in experimental dogs the gastroesophagolienal hemo- and lymphocirculation and that of the greater omentum were transferred into the system of the vena cava inferior, the mesenterial outflow being preserved through the liver. The dynamic observation of the experimental animals has shown the intervention performed to be valid. In 6 patients the gastroesophagolienal circulation and that of the greater omentum were transferred into the system of the vena cava inferior. The proposed method of surgical correction leads to lower portal pressure, to saved hepatopetal blood flow along the portal vein. The reestablished absorbing capacity of the greater omentum and the developed collateral lymph circulation decrease the transudation of the lymph into the abdominal cavity and increase its reabsorption.

Reassessment of monoethylglycinexylidide as preoperative liver function test in a rat model of liver cirrhosis and man

It is known that lidocaine is rapidly metabolized by the hepatic cytochrome P-450 system to form monoethylglycinexylidide (MEGX), its primary metabolite. We analyzed serum MEGX levels experimentally and clinically by fluorescent polarization immunoassay to reassess preoperative liver microsome functions.

EXPERIMENTAL STUDY

Liver cirrhosis was produced in rats by intra-abdominal injection of thioacetamide. MEGX, indocyanine green test (ICG), and liver biochemical variables were measured periodically. Then, survival rates were assessed after the rats received a 70% hepatectomy.

CLINICAL STUDY

MEGX levels were measured in various human patients with chronic hepatitis or liver cirrhosis who underwent hepatectomy. Serum MEGX levels significantly dropped and ICG levels significantly rose with macroscopic and histologic progression of liver cirrhosis in rats. The MEGX levels correlated closely with albumin levels and ICG. Preoperative MEGX and ICG levels of the mortal group of rats differed significantly from those of the survival group with 70% hepatectomy. Furthermore, 100% of the rats with MEGX levels above 40 ng/ml and ICG levels below 1.0%. In the clinical study, MEGX levels were significantly lower in patients with chronic hepatitis or liver cirrhosis than in healthy volunteers and correlated significantly with liver function tests such as albumin, Fischer's ratio, prothrombin time, hepaplastin and ICG. A significant difference was found in MEGX levels between patients receiving lobectomy and those receiving subsegmentectomy or partial hepatectomy. All patients tolerated their operations. Our data indicate that the MEGX test combined with ICG test and Child-Pugh classification is a better predictor of residual liver reserve capacity, and the analysis of hepatic MEGX formation might prove useful for rapid and reliable assessment liver function and choice of surgical treatment.

Effects of hepatic blood inflow occlusion on liver regeneration following partial hepatectomy in an experimental model of cirrhosis

BACKGROUND

Hepatic blood inflow occlusion during hepatectomy may influence postoperative liver regeneration. The aim of this study was to investigate the influence of hepatic blood inflow occlusion on liver regeneration following partial hepatectomy in thioacetamide-induced cirrhotic rats.

METHODS

Forty-three cirrhotic Wistar-Furth rats were randomly assigned to three groups. Rats in group 1 underwent 64 per cent hepatectomy alone, those in group 2 were subjected to 15 min hepatic blood inflow occlusion followed by 64 per cent hepatectomy, and animals in group 3 were subjected to 30 min inflow occlusion followed by 64 per cent hepatectomy. Liver function, 5-bromo-2'-deoxyuridine (BrdU) labelling index and percentage of initial liver weight on days 1, 2 and 7 posthepatectomy were assessed.

RESULTS

Rats in groups 1 and 2 had a significantly higher serum albumin level and a markedly lower alanine aminotransferase level than animals in group 3 on day 1 posthepatectomy (P < 0.05). There was no significant difference in the serum level of total bilirubin of the three groups on days 1, 2 and 7. The BrdU labelling index was significantly higher in groups 1 and 2 than in group 3 animals on day 1 posthepatectomy (P < 0.01 and P < 0.05 respectively). Percentages of initial liver weight were similar in groups 1, 2 and 3 on days 1, 2 and 7 after hepatectomy.

CONCLUSION

Hepatic blood inflow occlusion for up to 30 min suppressed DNA synthesis and hepatocyte proliferation at an early posthepatectomy stage and consequently delayed recovery of liver function in cirrhotic rats. However, it did not affect restoration of liver mass or survival after 64 per cent hepatectomy.

Treatment of carbon tetrachloride and phenobarbital-induced chronic liver failure with intrasplenic hepatocyte transplantation

Hepatocyte transplantation (HTx) has been shown to improve the survival of laboratory animals with experimentally induced acute liver failure and to ameliorate the physiologic abnormalities associated with liver-based metabolic deficiencies. However, the role of HTx in the treatment of liver cirrhosis (LC) has not been adequately studied. In order to address this issue, HTx was performed in rats following induction of stable LC using phenobarbital (PhB) and carbon tetrachloride (CCl4). Intrasplenic transplantation of 50 x 10(6) primary hepatocytes could significantly improve liver functions and prolong the survival of rats with irreversible, decompensated LC.

Portal flow augmentation for liver cirrhosis

BACKGROUND

Portal hypertension due to chronic liver disease is a major cause of death worldwide. Orthotopic liver transplantation offers the best therapeutic option but is available to only a minority of patients. In the past few years mechanically pumping portal venous inflow has been reported to reduce portal hypertension and improve liver function.

METHODS

A review of the published data on augmented portal perfusion for the treatment of portal hypertension in cirrhosis was carried out by searching Medline and other online databases. From each published study portal pressure and blood flow data before and after augmented portal perfusion were used to calculate the change in mean intrahepatic portal vascular resistance (IHPR). The standardized data were then combined to allow meta-analysis.

RESULTS

Seven papers were identified on normal and cirrhotic animal and human livers with augmented flow (50% to fourfold over baseline) for 30-180 min. Meta-analysis revealed that the increased portal venous inflow was associated with a significant rise in portal venous pressure on the hepatic side (P < 0.001), a significant reduction on the mesenteric side (P < 0.001) and a significant reduction in IHPR (P = 0.013). Limited data were available to support improved liver function.

CONCLUSION

Detailed in vivo cirrhotic liver studies on augmented portal flow in experimental models assessing haemodynamic and functional changes are required before clinical evaluation.

Effect of fetal tissue transplantation on reparative processes in experimental liver cirrhosis

Reparative regeneration after fetal tissue transplantation and after surgical stimulation was studied in rats with experimental cirrhosis of the liver. Fetal tissue restored the morphology and function of cirrhotic liver and modified functional activity of peritoneal macrophages.

Regenerative capacities of normal and cirrhotic livers following 70% hepatectomy in rats and the effect of alpha-tocopherol on cirrhotic regeneration

BACKGROUND

The regeneration of normal and cirrhotic liver has been very well demonstrated after partial hepatectomy; although the tissue regenerated by cirrhotic liver is also cirrhotic. The structural differences of the regenerated tissues between normal and cirrhotic livers may also indicate different regeneration capacities. The objective of this study was to compare the regeneration capacities of normal and cirrhotic livers by bromodeoxyuridine (BrdU) incorporation and proliferating cell nuclear antigen (PCNA) labeling indices in replicating nuclei and mitotic figures in cells in partially hepatectomized normal and cirrhotic rats and to study the effect of alpha-tocopherol on cirrhotic liver regeneration.

METHODS

Five groups of adult Wistar rats comprised normal livers, cirrhotic livers, regenerated normal livers, regenerated cirrhotic livers, and alpha-tocopherol-treated regenerated cirrhotic livers. Cirrhosis was induced by intragastric administration of carbon tetrachloride and phenobarbital in the drinking water of the rats. Liver regeneration capacities in normal and cirrhotic rats and following partial hepatectomy in normal and cirrhotic rats and cirrhotic rats that were administered alpha-tocopherol were evaluated through BrdU incorporation, PCNA labeling, and mitotic indices.

RESULTS

BrdU and PCNA labeling and mitotic indices were zero for normal rats and 4.3 +/- 3.5, 6.5 +/- 5, and 2.5 +/- 1.5 for cirrhotic rats, respectively. The values after partial hepatectomy in normal and cirrhotic rats were 46.2 +/- 8.7 and 27.8 +/- 7.5 for BrdU labeling, 83.7 +/- 6.5 and 51.3 +/- 6.8 for PCNA labeling, and 31.8 +/- 4.2 and 18.6 +/- 3.4 for mitotic index, respectively. For the fifth group comprising cirrhotic rats that were administered alpha-tocopherol and had undergone partial hepatectomy, BrdU incorporation, PCNA labeling, and mitotic indices were 37.5 +/- 6.3, 76.5 +/- 6.2, and 27.2 +/- 4.2, respectively. When the cirrhotic liver regeneration group was compared with the normal liver regeneration group, rates of liver regeneration in the cirrhotic group were significantly depressed (P < 0.01). Although the BrdU incorporation and PCNA labeling indices of the alpha-tocopherol-administered cirrhotic liver regeneration group indicated significantly lower rates of liver regeneration when compared with the normal liver regeneration group (P < 0.05), the liver regeneration rates of the alpha-tocopherol-administered cirrhotic group were also significantly higher than those of the cirrhotic liver regeneration group that was not administered alpha-tocopherol (P < 0.01).

CONCLUSIONS

Cirrhotic livers revealed a significantly depressed capacity for regeneration following partial hepatectomy. alpha-Tocopherol administration seemed to improve the rates of regeneration in cirrhotic rats with respect to the BrdU incorporation, PCNA labeling, and mitotic indices.

Hepatocyte transplantation in rats with decompensated cirrhosis

Hepatocyte transplantation improves the survival of laboratory animals with experimentally induced acute liver failure and the physiological abnormalities associated with liver-based metabolic deficiencies. The role of hepatocyte transplantation in treating decompensated liver cirrhosis, however, has not been studied in depth. To address this issue, cirrhosis was induced using phenobarbital and carbon tetrachloride (CCL(4)) and animals were studied only when evidence of liver failure did not improve when CCL(4) was held for 4 weeks. Animals received intrasplenic transplantation of syngeneic rat hepatocytes (G1); intraperitoneal transplantation of syngeneic rat hepatocytes (G2); intraperitoneal transplantation of a cellular homogenate of syngeneic rat hepatocytes (G3); intraperitoneal transplantation of syngeneic rat bone marrow cells (G4); or intrasplenic injection of Dulbecco's modified Eagle medium (DMEM) (G5). After transplantation, body weight and serum albumin levels deteriorated over time in all control (G2-G5) animals but did not deteriorate in animals receiving intrasplenic hepatocyte transplantation (G1) (P <.01). Prothrombin time (PT), total bilirubin, serum ammonia, and hepatic encephalopathy score were also significantly improved toward normal in animals receiving intrasplenic hepatocyte transplantation (P <. 01). More importantly, survival was prolonged after a single infusion of hepatocytes and a second infusion prolonged survival from 15 to 128 days (P <.01). Thus, hepatocyte transplantation can improve liver function and prolong the survival of rats with irreversible, decompensated cirrhosis and may be useful in the treatment of cirrhosis in humans.

Differential expression of apoptosis-associated genes post-hepatectomy in cirrhotic vs. normal rats

Liver regeneration after partial hepatectomy or liver injury is controlled by a wide variety of growth factors that are proven activators or inhibitors of hepatocyte proliferation. Liver regeneration post-hepatectomy has been proven to be decreased and delayed in cirrhotic vs. normal liver. Apoptosis seems to play an important role in cellular proliferation and in liver regeneration. Therefore, this study has analyzed the expression of apoptosis-associated genes following 2/3 hepatectomy in cirrhotic vs. normal rats. Cirrhosis was induced by a weekly intragastric administration of CCl4 for 16 weeks followed by hepatectomy and histological examination of the resected liver. Rats were sacrificed at 6 h, 12 h, 24 h, or 72 h after liver resection. The expression of proapoptotic (Bad, Bak, Bax) and antiapoptotic (Bcl-2, Bcl-XL) genes was analyzed by quantitative RT-PCR. We have observed an early increase in antiapoptotic mRNA levels and a delayed increase in proapoptotic mRNA levels in normal liver following hepatectomy. Before resection, proapoptotic mRNA levels were significantly higher in cirrhotic vs. normal liver. After hepatectomy, apoptotic mRNA levels were decreased and delayed as compared with that observed following hepatectomy in normal liver. These results indicate that apoptosis takes place in liver during CCl4-induced cirrhosis and could participate in the impaired regenerative response observed in cirrhotic liver.

Effect of preoperative interventions on outcome following liver resection in a rat model of cirrhosis

BACKGROUND/AIMS

High morbidity and mortality rates in cirrhotic patients undergoing resections for hepatocellular malignancies underscore the need for identifying a therapy that will decrease fibrosis or enhance hepatic regenerative activity in the perioperative period. Thus, in the present study, 104 carbon tetrachloride-induced cirrhotic rats received either saline (untreated cirrhotic controls) or one of the following agents that have been reported to decrease hepatic fibrosis or increase hepatic regeneration; pentoxifylline, ciprofloxacin or a traditional Chinese herbal remedy (TCHR). Twelve additional rats served as healthy, non-cirrhotic controls.

METHODS

Treatments were administered daily by gavage for 4 weeks followed by a 70% partial hepatectomy. Hepatic fibrosis was documented at the time of surgery by computer-assisted quantitation of collagen content. Liver function and hepatic regenerative activity were documented 24 h post partial hepatectomy by serum bilirubin determinations and a combination of 3[H]-Thymidine incorporation into hepatic DNA and proliferating cell nuclear antigen (PCNA) quantitation, respectively.

RESULTS

Compared to untreated cirrhotic controls (8.1 +/- 0.7%), fibrosis was significantly reduced in the pentoxifylline- and ciprofloxacin-treated groups (4.6 +/- 0.2%, p<0.005 and 5.5 +/- 0.6%, p<0.05) but unchanged in the TCHR-treated group (6.6 +/- 11.0%). Post-operatively, total serum bilirubin levels were lower in the pentoxifylline (1.40 +/- 0.15 mg/dl,p<0.01) and ciprofloxacin (1.87 +/- 0.25 mg/dl, p<0.05)-treated groups, but unchanged in the TCHR group (2.20 +/- 0.45 mg/dl), when compared to untreated cirrhotic controls (3.00 +/- 0.37 mg/dl). Hepatic regenerative activity was also significantly improved in the pentoxifylline-treated group (17.8 +/- 2.2 versus 9.9 +/- 1.9 DPM/microg DNA in untreated cirrhotic controls, p<0.05), but unchanged in the ciprofloxacin (16.1 +/- 1.8 DPM/microg DNA) and TCHR (10.9 +/- 1.2 DPM/microg DNA)-treated groups. PCNA protein determinations were in keeping with the 3[H]-Thymidine results

CONCLUSIONS

Pre-operative pentoxifylline holds promise as a useful therapeutic intervention for patients with cirrhosis requiring hepatic resection.

A canine model of multiple portosystemic shunting

The objective of this study was to develop and describe an experimental canine model of multiple acquired portosystemic shunts (PSS) similar in nature to spontaneously occurring PSS. Sixteen dogs were used and were divided into a control (n = 6) and a diseased group (n = 10). Dogs of the diseased group were administered dimethylnitrosamine (2 mg/kg of body weight, po) twice weekly, and clinicopathologic, ultrasonographic, and hepatic scintigraphic findings were recorded during the development of hepatic disease and PSS. Surgery was then performed to permit visual verification of multiple shunts, catheter placement for portography examination, and biopsy of the liver. All diseased dogs developed severe hepatic disease and multiple PSS as documented visually at surgery and on portography. Based on this study, dimethylnitrosamine-induced portosystemic shunting appears to be an appropriate model for spontaneously occurring multiple PSS secondary to portal hypertension.

[Hepatopulmonary syndrome: physiopathology of impaired gas exchange]

The hepatopulmonary syndrome (HPS) consists of a triad of liver dysfunction, increased alveolar-arterial oxygen gradient and intrapulmonary vascular dilations. The mechanisms of impaired arterial oxygenation are still debated but the multiple inert gases elimination technique and more recently contrast echocardiography, greatly facilitated the investigation of such mechanisms. Subsequently the cause of hypoxemia can be attributed to several mechanisms such as ventilation-perfusion mismatch, right-to-left intrapulmonary shunts and alveolar-to-capillary diffusion defect, variously implicated in the severity of the disease. SHP may result from intrapulmonary vascular dilations and angiogenesis but the pathogenesis of such abnormalities is not completely explained. The hypothesis of an imbalance in vasoactive mediators and angiogenic factors has been put forward. Increasing data support the theory that the increase in synthesis and release of nitric oxide (NO) is the key factor modulating vascular tone. If this hypothesis is true, the use of compettive inhibitors of NO synthesis should restore pulmonary vascular tone, reversing the hemodynamic changes and gas exchange impairment of HPS.

Pretreatment with soluble thrombomodulin prevents intrasinusoidal coagulation and liver dysfunction following extensive hepatectomy in cirrhotic rats

The major cause of posthepatectomy liver dysfunction is supposed to be microcirculatory disturbance caused by imbalance of intrasinusoidal coagulation equilibrium. Thrombomodulin (TM) is a potent anticoagulant expressed on the endothelial cell surface that regulates the coagulation system by binding thrombin and accelerating the thrombin-catalyzed activation of protein C. Therefore, we examined the effect of soluble TM purified from human urine (UTM) on intrasinusoidal coagulation in cirrhotic rats. Dimethylnitrosamine-induced cirrhotic rats underwent 70% hepatectomy and received endotoxin 48 h after. UTM or vehicle alone was intravenously administered to each rat 30 min before endotoxin injection. UTM treatment attenuated the increases in cytosolic enzymes and serum hyaluronic acid level. The UTM supply improved the survival rate of the rats at 12 h after endotoxin challenge. Histologically, intrasinusoidal fibrin depositions and massive hepatocellular necrosis observed in control rats were scarcely found in UTM-treated rats. Immunohistochemical examination revealed that marked TM stains in sinusoidal endothelial cells were well preserved in UTM-treated rats. In conclusion, UTM administration prevented intrasinusoidal fibrin depositions and attenuated posthepatectomy liver dysfunction in cirrhotic rats.

Functional capacity of the cirrhotic liver after partial hepatectomy in the rat

BACKGROUND

Posthepatectomy liver insufficiency is one of the most serious problems associated with a major hepatic resection, especially in the cirrhotic liver, which has less functional reserve than the normal liver. Evaluation of morphologic liver regeneration is important in cirrhotic rats, as well as in the normal liver, and assessment of functional capacity in cirrhosis is clinically important for preventing hepatic insufficiency of the remnant liver after hepatectomy.

METHODS

We evaluated the functional capacity of the cirrhotic liver induced by carbon tetrachloride in rats and studied the correlation between morphologic and functional restoration of the liver after partial hepatectomy in comparison with healthy rats. Morphologic restoration of the liver after hepatectomy was evaluated on the basis of remnant liver weight, proliferating cell nuclear antigen labeling index, and the DNA content of the regenerating liver. Functional restoration was evaluated by the indocyanine green disappearance rate and serum aminopyrine clearance.

RESULTS

Morphologic restoration in cirrhotic rats was delayed in comparison with healthy rats. Although functional capacity in the cirrhotic rats was diminished, functional restoration was advanced after a two-thirds hepatectomy, in comparison with morphologic restoration.

CONCLUSIONS

Functional restoration in cirrhotic rats after partial hepatectomy is advanced in comparison with morphologic restoration.

Manganese deposition in basal ganglia structures results from both portal-systemic shunting and liver dysfunction

BACKGROUND & AIMS

Manganese (Mn) deposition could be responsible for the T(1)-weighted magnetic resonance signal hyperintensities observed in cirrhotic patients. These experiments were designed to assess the regional specificity of the Mn increases as well as their relationship to portal-systemic shunting or hepatobiliary dysfunction.

METHODS

Mn concentrations were measured in (1) brain samples from basal ganglia structures (pallidum, putamen, caudate nucleus) and cerebral cortical structures (frontal, occipital cortex) obtained at autopsy from 12 cirrhotic patients who died in hepatic coma and from 12 matched controls; and from (2) brain samples (caudate/putamen, globus pallidus, frontal cortex) from groups (n = 8) of rats either with end-to-side portacaval anastomosis, with biliary cirrhosis, or with fulminant hepatic failure as well as from sham-operated and normal rats.

RESULTS

Mn content was significantly increased in frontal cortex (by 38%), occipital cortex (by 55%), pallidum (by 186%), putamen (by 66%), and caudate (by 54%) of cirrhotic patients compared with controls. Brain Mn content did not correlate with patient age, etiology of cirrhosis, or history of chronic hepatic encephalopathy. In cirrhotic and portacaval-shunted rats, Mn content was increased in pallidum (by 27% and 57%, respectively) and in caudate/putamen (by 57% and 67%, respectively) compared with control groups. Mn concentration in pallidum was significantly higher in portacaval-shunted rats than in cirrhotic rats. No significant changes in brain Mn concentrations were observed in rats with acute liver failure.

CONCLUSIONS

These findings suggest that brain Mn deposition results both from portal-systemic shunting and from liver dysfunction.

Portal branch ligation with a continuous hepatocyte growth factor supply makes extensive hepatectomy possible in cirrhotic rats

In a cirrhotic liver, the regenerative ability and specific functions are so impaired that excessive resection easily complicates postoperative liver dysfunction, which frequently leads to life-threatening multiple-organ failure. Hepatocyte growth factor (HGF), first identified as the most potent stimulator of DNA synthesis in primary hepatocytes, not only stimulates liver regeneration, but also accelerates hepatic function, improves fibrosis, and protects liver cells against injury. Therefore, we investigated the efficacy of preoperative portal branch ligation (PBL) (which can induce compensatory hypertrophy of the unaffected lobes) combined with a continuous HGF supply in the performance of extensive hepatectomy in cirrhotic rats. Cirrhosis was induced by intraperitoneal injections of dimethylnitrosamine (DMN) three times per week for 3 weeks. Five days after the last injection, when 70% hepatectomy is lethal, the rats underwent portal ligation of the left lateral and median branches (corresponding to approximately 70% of the total volume of the liver). Simultaneously, they were continuously treated with either recombinant human HGF (rhHGF) or vehicle from an intraperitoneally implanted osmotic pump. Four days after the portal ligation, the occluded lobes were resected. The HGF treatment rapidly increased both the wet weight of the unoccluded lobes and the hepatocellular DNA synthesis. The blood chemical analysis indicated that HGF significantly suppressed the posthepatectomy liver dysfunction. Most importantly, the HGF treatment markedly improved the survival rate of the rats at 48 hours after the major hepatectomy. In conclusion, PBL combined with a continuous HGF supply makes extensive hepatectomy possible in cirrhotic rats, mainly by promoting the hypertrophy of the unaffected lobes.

Glycogen-forming function of hepatocytes in the rat regenerating cirrhotic liver after a partial hepatectomy

Rat liver punctate biopsies were used for cytofluorimetric determinations of the content of glycogen and its fractions in hepatocytes, and also for microchemical measurements of the activity of glucose-6-phosphatase, glycogen phosphorylase, and glycogen synthase, in liver tissue with cirrhosis produced by carbon tetrachloride (CCl4) poisoning, during regeneration of the liver after the cessation of poisoning and after a partial resection of the cirrhosed liver. The liver cirrhosis was shown to be characterized by an accumulation of glycogen (predominantly of its metabolically less active fraction) in hepatocytes and by a decrease in the activities of the glycogenolytic enzymes in the liver parenchyma. On the cessation of poisoning, there was a partial or complete return to normal levels of the glycogen metabolism parameters. Some of them returned to normal more quickly if a partial hepatectomy was performed after the cessation of poisoning.

[The influence of intrahepatic transplantation of hepatocytes and insular cells on liver cirrhosis]

OBJECTIVE

To protect liver function, we used the cirrhotic rats to study whether the postshunt intrahepatic transplantation of hepatocytes and insular cells via hepatic artery can improve liver function.

METHOD

We irrigated the cirrhotic liver of rat via hepatic artery with hepatocytes and insular cells and observed the influence of this method on liver function.

RESULT

The improvement of TP, ALB and TBIL in the experimental group were significant, and there was significant difference in these parameters between the experimental and control groups (P < 0.01). Light microscopic examination of liver fibrosis and immunohistochemistry and data analysis of I, II collagens also showed significant difference (P < 0.05).

CONCLUSION

The intrahepatic transplantation of hepatocytes and insular cells via hepatic artery can not only improve liver function, but also increase the degradation of liver collagens and reverse the course of liver cirrhosis.

Vascular occlusion in hepatic resections in cirrhotic rat livers: an experimental study in rats

The aim of this study was to evaluate the tolerance of normothermic liver ischemia with different degrees of hepatic function in cirrhotic rats. Liver cirrhosis was induced by administering carbon tetrachloride (CCl4) in water solution to male Wistar rats. Hepatic function was graded using the plasma levels of antithrombin III, albumin, and bilirubin and the presence of ascites. Rats were distributed in four groups: noncirrhotic (control group), compensated cirrhosis (group A), decompensated cirrhosis (group B), and decompensated cirrhosis with ascites (group C). Groups A, B, and C were significantly different in all four parameters studied (P < .003). Subtotal liver ischemia was performed for periods of 0, 30, 45, 60, and 75 minutes. At the end of the procedure, the nonischemic lobes were resected. Postoperative evolution of alanine aminotransferase, aspartate aminotransferase, and bilirubin levels was also recorded. Survival rates after the same periods of ischemia were statistically different (P < .05): control group, 7 of 7 after 45 minutes (100%), 7 of 7 after 60 minutes (100%), and 4 of 9 after 75 minutes (44%); group A, 7 of 7 after 45 minutes (100%) and 1 of 7 after 60 minutes (14%); group B, 7 of 7 after 0 minutes (100%), 5 of 7 after 30 minutes (71%), and 1 of 7 after 45 minutes (14%); and group C, 0 of 5 after 0 minutes (0%) and 1 of 7 after 30 minutes (14%). No differences were found in the postoperative course of transaminases. However, bilirubin levels found 24 hours and 7 days after ischemia were significantly greater in cirrhotic rats, and this was directly related to the degree of hepatic insufficiency (P < .001). Histological examination of the livers exposed to CCl4 showed features of liver cirrhosis with ductal proliferation. The ischemia time tolerated by cirrhotic rat livers is shorter than the time tolerated by normal rats. Tolerance to hilar vascular occlusion depends on the degree of hepatic insufficiency. Rats with decompensated cirrhosis and ascites do not tolerate any surgical procedure.

Stimulation of liver regeneration and function after partial hepatectomy in cirrhotic rats by continuous infusion of recombinant human hepatocyte growth factor

BACKGROUND/AIMS

Radical resection is accepted as one of the most curative treatments for hepatocellular carcinoma. However, most patients have coexisting cirrhosis and their liver function is usually impaired. It is therefore important to stimulate the regeneration and function of the remnant cirrhotic liver after hepatectomy. Hepatocyte growth factor is a potent mitogen that has been suggested to play a crucial role in liver regeneration.

METHODS

In this study, we performed 45% hepatectomy in rats with cirrhosis induced by thioacetamide, and administered recombinant human hepatocyte growth factor (rhHGF) with dextran sulfate by continuous infusion into the jugular vein with an infusion pump.

RESULTS

rhHGF stimulated an increase in the wet weight of the remnant liver compared with untreated control rats. The proliferating cell nuclear antigen labeling index showed that this increase resulted from the stimulation of DNA synthesis. Serum levels of liver enzymes increased after hepatectomy, but returned to the prehepatectomy level more rapidly in rhHGF-treated rats than in controls. rhHGF increased hepatic protein synthesis above prehepatectomy levels and also markedly increased the serum levels of hepatic lipid metabolites.

CONCLUSIONS

These results demonstrate that continuous intravenous infusion of rhHGF enhances the growth and function of the remnant liver in rats with cirrhosis after partial hepatectomy. Therefore, rhHGF may be useful after hepatic resection in patients with cirrhosis.

Experimental, clinical, and metabolic results of side-to-side portacaval shunt for intractable cirrhotic ascites

BACKGROUND

Intractable ascites, refractory to medical therapy, occurs in approximately 10 percent of patients with ascites from cirrhosis and is almost always fatal. Sinusoidal hypertension resulting from hepatic venous outflow obstruction plays a primary role in the pathogenesis of cirrhotic ascites and provides the rationale for decompression of the liver by side-to-side portacaval shunt in treatment of intractable ascites. This report presents the experimental basis for the use of side-to-side shunt and long-term results of a prospective study in 34 selected patients with intractable cirrhotic ascites.

STUDY DESIGN

In the experimental studies, hepatic venous outflow obstruction and massive ascites were produced in dogs by ligation of the hepatic veins, and the effect of portacaval shunts on ascites, thoracic duct lymph flow, and aldosterone secretion were measured. In the clinical study, 34 carefully selected patients with cirrhosis (91 percent alcoholic) and truly intractable ascites (failure of medical therapy for 5 to 24 months) underwent side-to-side portacaval shunt. The effects on ascites, survival, metabolic abnormalities, and quality of life were studied prospectively during follow-up that was longer than 5 years in all but two patients. Quantitative Child's risk classes in percent of patients were A in 0, B in 68, and C in 32.

RESULTS

In the experimental studies, side-to-side portacaval shunt permanently relieved severe ascites, reduced the 13-fold increase in thoracic duct lymph flow rate to almost normal, and abolished the aldosterone hypersecretory response to minimal hepatic venous outflow obstruction. End-to-side portacaval shunt was much less effective. In the clinical study, side-to-side portacaval shunt reduced mean portal vein-inferior vena cava pressure gradient from 282 mm saline to 4 mm and permanently relieved all patients of ascites without subsequent requirement of diuretic therapy. Two patients who died of hepatoma, and one who died of heart failure developed terminal ascites. Thirty-day mortality rate was 6 percent, and long-term survival rates at 5, 10, and 15 years were 75 percent, 74 percent, and 73 percent. In metabolic studies, side-to-side shunt produced marked diuresis and natriuresis and abolished hypersecretion of aldosterone. Quality of life was generally improved as a result of a low incidence of recurrent portal-systemic encephalopathy (6 percent), abstinence from alcohol in 91 percent, improvement in liver function in 81 percent, and improvement in Child's risk class. The portacaval anastomosis remained permanently patent in every patient.

CONCLUSIONS

Side-to-side portacaval shunt is very effective treatment of intractable ascites from cirrhosis. Our results are attributable to careful selection of patients, an organized system of care, and a program of rigorous, lifelong follow-up that emphasizes abstinence from alcohol and dietary protein restriction.

Enhancement of proliferation of intrasplenically transplanted hepatocytes in cirrhotic rats by hepatic stimulatory substance

This study aimed at investigating the efficacy of hepatic stimulatory substance (HSS) on the proliferation of transplanted hepatocytes in the spleen of rats with carbon tetrachloride (CCl4)-induced liver cirrhosis. After hepatocyte transplantation (HTx; 1x10(7) cells/rat), the recipients received intravenous administration of HSS (3ml) of 2, 4, or 7 times/week to investigate the effect of the frequency of HSS treatment on the proliferation of intrasplenically transplanted hepatocytes. Next, to investigate the effect of the severity of liver cirrhosis on HSS-stimulated proliferation of transplanted hepatocytes, different doses (0.00, 0.08, 0.12, and 0.16 ml/week) of CCl4 were given to rats after HTx. The recipients were killed and the spleens were removed at 2 and 4 weeks after HTx and stained with bromodeoxyuridine (BrdU) and hematoxylin and eosin for determining the BrdU labeling index (L.I.) and the hepatocyte-occupied area ratio in the longitudinal cut surface of the spleen (H:S ratio), respectively. The H:S ratio was measured in the hematoxylin and eosin-stained splenic sections under a light microscope connected to an image processor. HSS-treated rats showed significantly higher BrdU L.I. and H:S ratios than the untreated control rats at 2 and 4 weeks after HTx. However, the difference in the BrdU L.I. and H:S ratio was not statistically significant among the HSS-treated rats. Without HSS treatment, the severity of liver cirrhosis did not affect the proliferation of intrasplenically transplanted hepatocytes. On the other hand, HSS-induced proliferation of transplanted hepatocytes was further enhanced in proportion to the severity of liver cirrhosis. The H:S ratio of the rats treated with 0.04, 0.08, and 0.16 ml/week of CCl4 after HTx was 1.27+/-0.5%, 4.32+/-0.65%, and 6.25+/-0.70%, respectively, at week 4. During the long-term observation of up to 12 weeks, a marked decrease in the H:S ratio was observed in HSS-untreated control rats at weeks 4-12 compared with week 2. While HSS-treated rats revealed gradual proliferation of intrasplenically transplanted hepatocytes, the difference in the H:S ratio between HSS-treated and -untreated rats became larger. These results indicate that HSS treatment of recipient rats stimulated the proliferation of intrasplenically transplanted hepatocytes in cirrhotic rats and that the severity of liver cirrhosis enhanced the stimulative effect of HSS on the proliferation of transplanted hepatocytes.

Bilioenteric anastomosis reverses hyperkinetic circulation in bile duct-ligated cirrhotic rats

BACKGROUND/AIMS

The chronic bile duct-ligated rat is used to study hemodynamic changes in cirrhosis but suffers from total biliary obstruction and deep jaundice. The extent of reversibility of hemodynamics and histology following bile flow reconnection is controversial. We aimed to characterize the hemodynamics and histology of bile duct-ligated cirrhotic rats in which bile flow was reconnected by a Roux-en-y choledochojejunostomy.

METHODS

Operations created four groups: double sham (control), bile duct ligated, and two reconnected groups. Cardiac index and regional blood flows were measured by radioactive microspheres 4 weeks following the last operation in the first three groups and 8 weeks afterwards in the second reconnected group. Liver histology was assessed by a computer-aided scoring program.

RESULTS

Cardiac index, mean arterial pressure, and systemic vascular resistance in the reconnected groups were different from bile duct-ligated rats and returned to control values. Portal pressures in the reconnected groups (4-weeks, 10.0 +/- 0.5 and 8-week, 9.7 +/- 0.6 mmHg) were significantly lower than in bile-duct-ligated rats (13.7 +/- 0.6) but remained elevated compared to controls (7.0 +/- 0.3). Portal pressure in the reconnected rats was correlated with cardiac index and mesenteric blood flow, r = 0.66 and r = 0.45, respectively. Liver histology was improved in the reconnected rats, with decreased bile duct proliferation, fibrosis and apoptosis.

CONCLUSIONS

We conclude that many of the histological features of secondary biliary cirrhosis are reversible after bilioenteric anastomosis. Furthermore, the hyperdynamic circulation is also largely reversible and is related to the degree of portal hypertension.

[Changes of Kupffer cell DNA and RNA synthetic functions after partial hepatectomy in cirrhotic rats]

We studied the changes of DNA and RNA synthetic functions of regenerating liver cells after partial hepatectomy in cirrhotic rats and discussed the relationship between liver regeneration and liver functional failure. Seventy healthy male Wistar rats weighing 200 approximately 250 g, were randomized into sham-operated (SO), partial hepatectomy in cirrhotic rats (C-PH) and partial hepatectomy in normal rats (N-PH). The left and middle lobes were dissected. The synthetic DNA peak of Kupffer cells (KC) in the G2 and M phase in C-PH was found after 24 hr of operation. The regenerating index peak of KC was at 48 hr after operation, which was higher than the other groups, but the liver weights in C-PH was lower than that in the N-PH at 1 week after operation. The RNA content of KC markedly decreased and returned to normal levels at 1 week after operation. We think that KC functions are suppressed after partial hepatectomy in cirrhotic rats. It is an important cause of hepatocyte regeneration function decrease and liver functional failure for delay of liver cell regeneration "start" and the regeneration cell cycle.

[Stimulation of regenerative processes and correction of the functional activity of the liver in its partial resection and toxic lesions]

The effects of hepatotropic growth factors (HGFs) and phospholipid drugs on the recovery of functions and the regeneration of the rat liver were studied in CC14-induced toxic damage and after partial hepatectomy (PHE). HGFs isolated from the cytoplasmic cells of the regenerating liver, as well as from the liver of the animals given prodigiozan and from the media taken after culturing the explants of the regenerating liver were found to stimulate DNA synthesis and hepatocytic proliferation following PHE and in the cirrhotic liver. Prodigiozan was shown to induce the formation of HGFs not only in the rat liver following PHE, but in the liver of intact animals. It was established that the covalently binding complex of albumin and bilirubin stimulated the synthesis of proteins and DNA in the regenerating liver, but non-covalently binding complex inhibited these processes. When CC14 was administered to the animals, the two complexes enhanced the reparative synthesis of DNA, without changing the level of replicating synthesis, the non-covalently binding complex completely eliminating the single-strand breaks in DNA. Phospholipid agents containing soybean and sunflower phosphatidylcholines increased the synthesis of RNA and albumin, which were decreased due to exposure to CC14 and had the property of stimulating the synthesis of total DNA and considerably enhancing that of mitochondrial DNA.

Significance of aminopyrine breath test as a parameter of hepatic functional reserve in 40% partial hepatectomy of rats with CCl4-induced liver injury

Rats with CCl4-induced liver injury underwent partial (40%) hepatectomy. The [14C]aminopyrine breath test (ABT) values in rats with CCl4-induced liver injury were reduced by 34% compared with those in rats with normal liver. Preoperative ABT values clearly discriminated between survivors and those that died following 40% partial hepatectomy in rats CCl4-induced liver injury (P < 0.05). Hepatic protein synthesis was remarkably enhanced in CCl4-induced liver injury compared with normal liver (P < 0.001), and this was inversely correlated with ABT values (P < 0.001). These data show that the enhanced hepatic protein synthesis could induce a decrease of hepatic functional reserve. ABT seems to be a useful preoperative test for predicting surgical mortality following hepatectomy.

[Quantitative changes of hepatic microcirculation and mitochondrial function after splenectomy in liver cirrhosis rats]

To evaluate the potential risk of splenectomy for patients with cirrhotic liver. I measured quantitative time-course changes of portal pressure (PP), and hepatic tissue blood flow (TBF) by hydrogen clearance method and adenine nucleotides by HPLC in a rat model. Intraperitoneal thioacetamide injection (200mg/kg x 30) produced histologically proven cirrhotic liver (TAAs) as well as increasing the spleen weight and PP compared to controls. PP and TBF simultaneously decreased on the 1st postoperative day (POD) after splenectomy in TAAs, whereas controls showed no changes in these parameter after splenectomy. Although PP of TAAs remained decreased until the 7th POD after splenectomy, their TBF gradually increased between the 2nd and 7th PODs returning to the baseline value. Recovery of ATP or energy charge after their decrease on the 1st POD was delayed in TAAs. Splenectomy in TAAs enhanced the deterioration of energical metabolism. Splenectomy in cirrhotic rats resulted in an additional postoperative risk.