Factors Affecting Liver Regeneration in Living Donors After Hepatectomy

Liver regeneration of living donor after liver donation for transplantation: Disparity in the left and right remnant liver

Donor safety is crucial for living donor liver transplantation (LDLT), and sufficient liver regeneration significantly affects outcomes of living donors. This study aimed to investigate clinical factors associated with liver regeneration in living donors. The study retrospectively reviewed 380 living donors who underwent liver donation at Chang Gung Memorial Hospital in Linkou. The clinical characteristics and medical parameters of donors were analyzed and compared according to liver donation graft type. There were 355 donors (93.4%) with right hemi-liver donations and 25 donors (6.6%) with left hemi-liver donations. Left hemi-liver donors had a higher body mass index (BMI) and a larger ratio of remnant liver volume (RLV) to total liver volume (TLV). However, the 2 groups showed no significant difference in the liver regeneration ratio. The type of remnant liver (P < .001), RLV/body weight (P = .027), RLV/TLV (P < .001), serum albumin on postoperative day 7 and total bilirubin levels on postoperative day 30 were the most significant factors affecting liver regeneration in living donors. In conclusion, adequate liver regeneration is essential for donor outcome after liver donation. The remnant liver could eventually regenerate to an adequate volume similar to the initial TLV before liver donation. However, the remnant left hemi-liver had a faster growth rate than the remnant right hemi-liver in donors.

Volumetric Remodeling of the Left Liver After Right Hepatectomy: Analysis of Factors Predicting Degree of Hypertrophy and Post-hepatectomy Liver Failure

BACKGROUND

This study investigated the volumetric remodeling of the left liver after right hepatectomy looking for factors predicting the degree of hypertrophy and severe post-hepatectomy liver failure (PHLF).

METHODS

In a cohort of 121 right hepatectomies, we performed CT volumetrics study of the future left liver remnant (FLR) preoperatively and postoperatively. Factors influencing FLR degree of hypertrophy and severe PHLF were identified by multivariate analysis.

RESULTS

After right hepatectomy, the mean degree of hypertrophy and kinetic growth rate of the left liver remnant were 25% and 3%/day respectively. The mean liver volume recovery rate was 77%. Liver remodeling volume was distributed for 79% on segments 2 and 3 and 21% on the segment 4 (p<0.001). Women showed a greater hypertrophy of segments 2 and 3 compared with men (p=0.002). The degree of hypertrophy of segment 4 was lower in case of middle hepatic vein resection (p=0.004). Left liver remnant kinetic growth rate was associated with the standardized future liver remnant (sFLR) (p<0.001) and a two-stage hepatectomy (p=0.023). Severe PHLF were predicted by intraoperative transfusion (p=0.009), biliary tumors (p=0.013), and male gender (p=0.022).

CONCLUSIONS

Volumetric remodeling of the left liver after right hepatectomy is not uniform and is mainly influenced by gender and sacrifice of middle hepatic vein. Male gender, intraoperative transfusion, and biliary tumors increase the risk of postoperative liver failure after right hepatectomy.

Defective endoplasmic reticulum stress response via X box-binding protein 1 is a major cause of poor liver regeneration after partial hepatectomy in mice with non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. Poor regeneration after hepatectomy in NAFLD is well recognized, but the mechanism is unclear. Endoplasmic reticulum (ER) stress plays an important role in the development of NAFLD. Here, we show that an impaired ER stress response contributes to poor liver regeneration in partially hepatectomized mice.

METHODS

Non-alcoholic fatty liver (NAFL) or non-alcoholic steatohepatitis (NASH) was induced in mice using our patented feed and 70% partial hepatectomy (PH) was performed. Mice were sacrificed 0, 4, 8, 24, or 48 hours, or 7 days after PH, and liver regeneration and the mRNA expression of ER stress markers were assessed.

RESULTS

Non-alcoholic fatty liver disease activity score was calculated as 4-6 points for NAFL and 7 points for NASH. NASH was characterized by inflammation and high ER stress marker expression before PH. After PH, NASH mice showed poorer liver regeneration than controls. High expression of proinflammatory cytokine genes was present in NASH mice 4 hours after PH. Xbp1-s mRNA expression was high in control and NAFL mice after PH, but no higher in NASH mice.

CONCLUSIONS

Dysfunction of the ER stress response might be a cause of poor liver regeneration in NASH.

Series of Intravoxel Incoherent Motion and T2* Magnetic Resonance Imaging Mapping in Detection of Liver Perfusion Changes and Regeneration Among Partial Hepatectomy in Sprague-Dawley Rats

RATIONALE AND OBJECTIVES

To evaluate liver perfusion changes and their effect on liver regeneration (LR) after partial hepatectomy (PH) using intravoxel incoherent motion (IVIM) and T2* mapping in a rat model.

METHODS

One hundred and two rats underwent 30%, 50%, or 70% PH. Within each group (n = 34), rats in MR imaging subgroup (n = 10) underwent liver IVIM and T2* mapping before and within 2 h, 1, 2, 3, 5, 7, 14, and 21 days post-PH to measure D*, perfusion fraction (PF), and T2* values. Three rats from histologic subgroup (n = 24) sacrificed at each time point for hepatocyte Ki-67 indices and diameters measurement.

RESULTS

Liver D* and PF values decreased immediately post-PH, then returned to original level as LR progressed in all groups. PF values in 70% PH group were significantly lower than in the other two groups (p < .05). D* and PF values correlated significantly with hepatocyte Ki-67 indices (r =  -0.588 to -0.915; p < .05) and hepatocyte diameter (r  = -0.555 to -0.792; p < .05). Liver T2* values decreased immediately within 2 h post-PH, then increased to a high level and followed with returning to original level gradually. The duration of the high T2* levels was consistent with Ki-67 indices.

CONCLUSIONS

Liver perfusion decreased immediately followed with increasing gradually after PH. IVIM and T2* mapping are promising methods for monitoring changes of liver perfusion. IVIM-derived D* value is the best indicator in reflecting the process of LR noninvasively.

Comparison of liver regeneration between donors and recipients after adult right lobe living-donor liver transplantation

BACKGROUND

Living-donor liver transplantation (LDLT) is recognized as the standard treatment for end-stage liver diseases. The regeneration of the residual liver and graft after LDLT is important in evaluating surgical success. Previous studies have attempted to elucidate mechanisms, principles of liver regeneration after LDLT, or influencing factors. However, they have not ruled out patients with complications and reached a uniform conclusion. In this study, for the first time, we unified measurement methods of liver volumes and eliminated patients with complications to compare liver regeneration trends between donors and recipients after LDLT and search for potential influencing factors.

METHODS

A total of 61 donors and 62 recipients without complications after adult right lobe LDLT were included in this retrospective observational cohort study. The liver regeneration ratios (LRRs) at different time points in donors and recipients after LDLT were calculated and compared. Factors that affect LRRs include gender, age, graft with or without the middle hepatic vein (MHV), initial remnant liver (IRLV)/estimated standard liver volume (ESLV), initial graft volume (IGV)/ESLV, Child-Pugh grade, and model for end-stage liver disease (MELD) score of the recipients. Analysis of variance, independent-sample t-test, and correlation analysis were performed for statistical analyses.

RESULTS

Significant differences were found in LRRs between the donors and recipients after LDLT (all P<0.05). The LRRs of donors at 0.5, 1, 3, and 6 months were 80.80%±24.12% (72.87%, 88.73%), 98.62%±37.47% (75.97%, 121.26%), 103.34%±23.47% (83.73%, 122.96%), and 130.18%±17.68% (102.04%, 158.32%), respectively. The LRRs of recipients at 0.5, 1, 3, and 6 months were 58.49%±26.67% (49.04%, 67.95%), 50.16%±27.25% (40.94%, 59.38%), 44.36%±26.75% (35.30%, 53.41%), and 31.19%±22.57% (20.91%, 41.47%), respectively. The former values were higher than the latter. The LRRs of recipients with the MHV was higher than those without MHV at 1 and 3 months (P<0.05). The LRRs at 1 month were 59.63%±27.48% and 41.68%±24.73%, and at 3 months were 57.25%±25.42% and 32.81%±22.79%, respectively. The IRLV/ESLV and IGV/ESLV were negatively correlated with LRRs at several times [r=-0.419 (-0.646, -0.134), -0.608 (-0.832, -0.318), respectively; P<0.05]. At 0.5 month, significant difference was found between Child-Pugh score of ≤9.55 and >9.55 (P<0.05) and MELD score of ≤14 and >14 (P<0.05).

CONCLUSIONS

After LDLT, donors had more significant and faster liver regeneration than the recipients. Graft with or without MHV, initial liver volume, and preoperative liver function status of the recipients significantly affect liver regeneration.

Impact of laparoscopic liver resection on liver regeneration

BACKGROUND

Liver regeneration after liver resection plays an important role in preventing posthepatectomy liver failure. In this study, we aimed to evaluate and compare the impact of laparoscopic liver resection (LLR) and open liver resection (OLR) on liver regeneration.

METHODS

Patients who underwent curative anatomical liver resection for hepatocellular carcinoma, cholangiocellular carcinoma, and colorectal liver metastases at our institution between January 2010 and December 2018 were included in this study. The patients were divided into the OLR and LLR groups. Preoperative liver volume (PLV), future remnant liver volume, resected liver volume (RLV), liver volume at 1 month after the surgery, and liver volume at 6 months after the surgery were calculated. The liver regeneration rate was defined as the increase in the rate of RLV, and the liver recovery rate was defined as the rate of return to the PLV.

RESULTS

The study included 72 patients. Among them, 43 were included in the OLR group and 29 were included in the LLR group. No differences were observed in the baseline characteristics and surgical procedures between the two groups. Moreover, no significant difference was observed in the liver regeneration rate at 1 month after the surgery (OLR vs. LLR: 68.9% vs. 69.0%, p = 0.875) and at 6 months after the surgery (91.8% vs. 93.2%, p = 0.995). Furthermore, the liver recovery rates were not significantly different between the two groups at 1 month after the surgery (90.3% vs. 90.6%, p = 0.893) and at 6 months after the surgery (96.9% vs. 98.8%, p = 0.986).

CONCLUSION

Liver regeneration after liver resection is not affected by the type of surgical procedure and both laparoscopic and open procedures yield similar regeneration and recovery rates.

Donor Morbidity Is Equivalent Between Right and Left Hepatectomy for Living Liver Donation: A Meta-Analysis

Maximizing liver graft volume benefits the living donor liver recipient. Whether maximizing graft volume negatively impacts living donor recovery and outcomes remains controversial. Patient randomization between right and left hepatectomy has not been possible due to anatomic constraints; however, a number of published, nonrandomized observational studies summarize donor outcomes between 2 anatomic living donor hepatectomies. This meta-analysis compares donor-specific outcomes after right versus left living donor hepatectomy. Systematic searches were performed via PubMed, Cochrane, ResearchGate, and Google Scholar databases to identify relevant studies between January 2005 and November 2019. The primary outcomes compared overall morbidity and incidence of severe complications (Clavien-Dindo >III) between right and left hepatectomy in donors after liver donation. Random effects meta-analysis was performed to derive summary risk estimates of outcomes. A total of 33 studies (3 prospective and 30 retrospective cohort) were used to identify 7649 pooled patients (5993 right hepatectomy and 1027 left hepatectomy). Proportion of donors who developed postoperative complications did not significantly differ after right hepatectomy (0.33; 95% confidence interval [CI], 0.27-0.40) and left hepatectomy (0.23; 95% CI, 0.17-0.29; P = 0.19). The overall risk ratio (RR) did not differ between right and left hepatectomy (RR, 1.16; 95% CI, 0.83-1.63; P = 0.36). The relative risk for a donor to develop severe complications showed no differences by hepatectomy side (Incidence rate ratio, 0.97; 95% CI, 0.67-1.40; P = 0.86). There is no evidence that the overall morbidity differs between right and left lobe donors. Publication bias reflects institutional and surgeon variation. A prospective, standardized, multi-institutional study would help quantify the burden of donor complications after liver donation.

Longitudinal profiling of plasma and urine metabolites during liver regeneration in living liver donors

BACKGROUND

Knowledge of metabolic processes affected by major hepatectomy (MHx), and the metabolic pathways involved in liver regeneration and recovery of function, is limited and mainly derived from animal models. Assessment of restoration of hepatic function is essential in human living liver donors (LD).

METHODS

We used a targeted metabolomic approach to longitudinally quantify changes in plasma and urine biomarkers from healthy LD. The biomarkers were analyzed before MHx and at scheduled intervals up to 12 months thereafter.

RESULTS

Marked changes were found in the concentration of 15 primary and secondary plasma bile acids. Most significant changes occurred 2 days after MHx and persisted for up to 3 months. In addition, there were significant changes in acylcarnitine, phospholipid, and amino acid metabolism. The sum of aromatic amino acids and the Fischer ratio, both metabolic markers of liver damage, and the symmetrically demethylated arginine to arginine ratio, a marker of kidney function, were affected.

CONCLUSIONS

This is the first comprehensive longitudinal study investigating metabolic processes during recovery of liver function after MHx in LD. It provides further evidence of full restoration of metabolic processes 3 months after MHx and supports future investigation to understand how metabolic changes affect donors' hepatic function.

Additional partial hepatectomy at the time of portal vein ligation accelerates the regeneration of the future liver remnant

Portal vein ligation (PVL) has been adopted to induce hypertrophy of the future liver remnant (FLR) in patients with primarily irresectable liver tumor. However, regeneration of the FLR is not always sufficient to allow curative resection of the portally-deprived tumor-bearing liver lobe. We hypothesize that simultaneous hepatectomy (PHx) and PVL augments regeneration of the FLR and that the effect is related to the extent of the additional resection. Seventy-two Lewis rats were enrolled into 3 groups: 20%PVL + 70%PHx; 70%PVL + 20%PHx; 90%PVL. Animals were observed for 1, 2, 3 and 7 days postoperatively (n = 6/time point). Liver enzymes, caudate liver/body-weight-ratio, BrdU-proliferation-index (PI), proliferating-cell-nuclear-antigen (PCNA)-mRNA-expression level and autophagy-related-proteins were evaluated. Compared with 90% PVL, additional PHx induced significantly more hypertrophy during the observation time, which was confirmed by significantly higher PI and higher level of PCNA-mRNA expression. Similarly, the additional PHx induced more autophagy in the FLR compared with PVL alone. However, both effects were not clearly related to the extent of additional resection. Additional resection augmented liver regeneration and autophagy substantially compared with PVL alone. Therefore, we concluded that autophagy might play a critical role in regulating hepatocyte proliferation and the size of the FLR after simultaneous PVL + PHx.

[Liver regeneration: resolved and problem issues]

Liver is an exceptional organ due to unique anatomical and physiological features, as well as advanced regenerative ability. Discovery of molecular mechanisms governing liver regeneration allowed researchers to use them to enhance liver regeneration. However, significant progress in this area was achieved through the introduction of gene therapy. In this manuscript, the authors consider stem cells for cell therapy and tissue engineering, as well as an alternative to liver transplantation.

Differentiation of Cells Isolated from Afterbirth Tissues into Hepatocyte-Like Cells and Their Potential Clinical Application in Liver Regeneration

Toxic, viral and surgical injuries can pose medical indications for liver transplantation. The number of patients waiting for a liver transplant still increases, but the number of organ donors is insufficient. Hepatocyte transplantation was suggested as a promising alternative to liver transplantation, however, this method has some significant limitations. Currently, afterbirth tissues seem to be an interesting source of cells for the regenerative medicine, because of their unique biological and immunological properties. It has been proven in experimental animal models, that the native stem cells, and to a greater extent, hepatocyte-like cells derived from them and transplanted, can accelerate regenerative processes and restore organ functioning. The effective protocol for obtaining functional mature hepatocytes in vitro is still not defined, but some studies resulted in obtaining functionally active hepatocyte-like cells. In this review, we focused on human stem cells isolated from placenta and umbilical cord, as potent precursors of hepatocyte-like cells for regenerative medicine. We summarized the results of preclinical and clinical studies dealing with the introduction of epithelial and mesenchymal stem cells of the afterbirth origin to the liver failure therapy. It was concluded that the use of native afterbirth epithelial and mesenchymal cells in the treatment of liver failure could support liver function and regeneration. This effect would be enhanced by the use of hepatocyte-like cells obtained from placental and/or umbilical stem cells.

Liver fibrosis is a major risk factor for liver regeneration: A comparison between healthy and fibrotic liver

BACKGROUND

Blood flow factors, such as congestion or ischemia after hepatectomy, have a significant impact on liver regeneration, but with the popularization of precise hepatectomy technology, segmental hepatectomy without congestion or ischemia has become the preferred treatment. Our aim is to investigate the factors affecting liver regeneration after hepatectomy without blood flow changes, and to provide clinical evidence for surgeons on the timing of second hepatectomy for cirrhosis patients with hepatocellular carcinoma (HCC).

METHODS

This study retrospectively analyzed data from patients who underwent right hepatectomy without middle hepatic vein (MHV) in West China Hospital between January 2016 and January 2018. Eighteen living-donors without MHV as normal group and 45 HCC patients, further classified into 3 subgroups based on the severity of fibrosis using the Scheure system. Demographic data, pre- and postoperative liver function indexes, and remnant liver volume (RLV) were retrospectively compared. We also analyzed the remnant liver regeneration rate (RLRR) post-operatively in each group. The significant indexes in univariate analysis were further analyzed using both receiver operating characteristic (ROC) analysis and multivariate regression analysis.

RESULTS

Liver regeneration occurred in both living-donor and HCC groups after hepatectomy; the RLRRs at 1 month were 59.46 ± 10.39% and 57.27 ± 4.77% (P = .509), respectively. Regeneration in the cirrhosis group occurred more slowly and less completely compared with that in other groups. The regeneration rate in the first 6 months showed rapid increase and the RLRR reached above 70% in cirrhosis group. Multivariate and ROC analyses revealed that Alb and the hepatic fibrosis grade in the early postoperative period were significant predictors of remnant liver regeneration.

CONCLUSION

The liver regenerated in all HCC patients; however, regeneration was significantly slower and less complete compared with the normal liver, especially in the patients with cirrhosis. Therefore, it can be concluded that the degree of liver fibrosis is a major predictor of liver regeneration. Furthermore, the optimal time for second resection in recurrent HCC patients with cirrhosis was 6 months after the first operation.

[Liver regeneration after resection in clinical and experimental conditions]

The researches devoted to postoperative liver regeneration and influence in this process were analyzed. Liver injury is followed by hypertrophy of residual liver parenchyma. The use of various cytokines is perspective for activation, acceleration and inhibition of liver recovery. Cellular technologies in the treatment of liver diseases can affect its repair. Moreover, these methods could make unnecessary resection and transplantation of liver in certain cases. It is generally accepted that the main effect of multipotent stromal cells (MSC) in liver failure is associated with their differentiation to the cellular elements of this organ. At the same time, recent reports revealed that MSC injection to the liver is followed by their quick death, dissemination to other organs and tissues or even elimination from the organism. Regeneration of non-parenchymal structures (vascular network and bile ducts) should be considered in addition to functional recovery of liver parenchyma after resection. Clarification of indications and contraindications for MSC therapy, as well as prevention of possible complications associated with cellular technologies are required.

Influence of the Glissonean Pedicle Transection Approach in Spiegel Lobe-Preserving Left Hepatectomy on Spiegel Lobe Volume and Remnant Liver Functions

BACKGROUND

The extrahepatic surgical technique in liver resection can be divided into glissonean pedicle transection and glissonean separated transection approaches. In this study, we compared remnant liver function and liver regeneration involving the Spiegel lobe between these two approaches regarding Spiegel lobe-preserving left hepatectomy.

METHODS

We enrolled 31 patients who underwent Spiegel lobe-preserving left hepatectomy for malignant hepatobiliary diseases between April 2008 and January 2020. The postoperative Spiegel lobe volume was measured using a volume analyzer at 3 and 6 months postoperatively.

RESULTS

Of the 31 patients, 22 and 9 were included in the glissonean separated transection and glissonean pedicle transection groups, respectively. There was no significant between-group difference in the preoperative Spiegel lobe volume. However, the volumes at 3 and 6 months postoperatively were significantly larger in the glissonean pedicle transection group than in the glissonean transection group (29.92 mL vs. 13.00 mL; P < 0.001 and 28.43 mL vs. 15.01 mL; P < 0.001, respectively). There was no significant between-group difference in postoperative remnant liver function.

CONCLUSIONS

The postoperative Spiegel lobe volume was larger, and liver regeneration was better with the glissonean pedicle transection approach because of transection for Spiegel branch of the portal vein. It is desirable to preserve Spiegel branch in possible cases when surgeons select the glissonean separated transection approach based on the location and size of the tumors.

Hepatoprotective effect of opioid peptides in stress

Introduction: Influence of the endogenous opioid system on the liver has not been studied enough. To understand the damaging effects of stress on the liver and the hepatoprotective effects of opioids, a study was performed on stress-resistant and stress-susceptible animals.

Materials and methods: The investigation was performed on 725 Wistar male-rats. Various types of stress were modeled: acute immobilization stress of various duration (3, 6 and 12 hours), chronic stress of limited mobility, swimming stress and traumatic stress (resection of 70% of the liver). Agonists of various types of opioid receptors in equimolar doses were injected to stressed animals at equimolar doses: DAGO – a mu-receptor agonist – at a dose of 6.3 mcg/kg, DSLET – a delta-receptor agonist – at a dose of 10 mcg/kg, and kappa receptor agonist dynorphin A (1-13) – at a dose of 20.1 mcg/kg.

Results and discussion: The stress-limiting action of the studied opioids is characterized by the reduced hepatocyte dystrophy, microcirculation correction, a decreased concentration of lipid peroxidation metabolites, a suppressed cytolytic syndrome, a stimulated synthetic ability of the liver, and is more pronounced in stress- susceptible animals. The greatest stress-protective effect is shown after administering dynorphin A (1-13) in immobilization stress, and DAGO – in swimming stress. Dynorphin A (1-13) and DAGO manifested the most pronounced effect on the liver regeneration after resection. A preliminary stress simulation accelerates liver regeneration at the initial stage after resection.

Conclusion: The hepatoprotective effect of opioids in stress depends on the typological peculiarities of animals. The results obtained offer a challenge of synthesizing new hepatoprotectors.

Effects of thymoquinone and curcumin on the regeneration of rat livers subject to 70% hepatectomy

PURPOSE

To investigate thymoquinone, curcumin and a combination of these two drugs were effective or not at the growth of liver.

METHODS

Forty female Wistar-Albino rats distributed into five groups of eight rats each, control, thymoquinone, curcumin, and thymoquinone/curcumin groups. Pathological specimens were studied using the Ki-67 Proliferation Index(PI); and arginase(Arg), tissue plasminogen activator(tPA), ceruloplasmin(Cer) and nitric oxide(NO) were studied in biochemical analysis.

RESULTS

Our results showed that Ki-67 proliferation index was low in Groups 1. The proliferation coefficient was significantly higher in the Group 2 and Group 4 than in the Group 1 and Group 3.(P < 0.001 between Groups 1 and 2, 1 and 4, and 3 and 4). There was no difference between Groups 2 and 4 (P = 1). The results of the biochemical Arg, tPA and Cer test showed statistically between the Group 1 and Group 2. NO showed significant differences Group 1 and 3.

CONCLUSIONS

Thymoquinone and curcumin both have known positive effects on the organism. Histological and biochemical tests showed that thymoquinone is more effective than curcumin.