Liver Regeneration In Patients Research Articles

Liver regeneration after hepatectomy is significantly suppressed in a muscular atrophy mouse model.

Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength. As reported in previous studies, the loss of skeletal muscle mass is associated with poor liver regeneration after hepatectomy. It is considered important to clarify the effect of sarcopenia on liver regeneration; however, there are no reports about model animals for sarcopenia. We focused on the peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α) transgenic mice that overexpressed PGC-1α, specifically for skeletal muscle, and showed significant atrophy of type 2B fiber-rich muscles like sarcopenia. We performed 70% hepatectomy using PGC-1α transgenic mice and examined the liver regeneration rate and the effects of branched-chain amino acids (BCAA) after hepatectomy. Liver regeneration after 70% hepatectomy was significantly suppressed in the PGC-1α transgenic mice. In addition, a decrease in the blood BCAA concentration and a decrease in the liver glycogen content after 70% hepatectomy were observed in the PGC-1α transgenic mice. By administering BCAA before and after surgery, it was clarified that a significant increase in the blood BCAA concentration was observed and the liver regeneration rate was improved in the PGC-1α transgenic mice. BCAA administration may improve the suppression of liver regeneration in patients with sarcopenia.

The Influence of Hepatic Steatosis and Fibrosis on Postoperative Outcomes After Major Liver Resection of Perihilar Cholangiocarcinoma

BackgroundSurgical resection for perihilar cholangiocarcinoma (pCCA) is associated with high operative risks. Impaired liver regeneration in patients with pre-existing liver disease may contribute to posthepatectomy liver failure (PHLF) and postoperative mortality. This study aimed to determine the incidence of hepatic steatosis and fibrosis and their association with PHLF and 90-day postoperative mortality in pCCA patients.MethodsPatients who underwent a major liver resection for pCCA were included in the study between 2000 and 2021 from three tertiary referral hospitals. Histopathologic assessment of hepatic steatosis and fibrosis was performed. The primary outcomes were PHLF and 90-day mortality.ResultsOf the 401 included patients, steatosis was absent in 334 patients (83.3%), mild in 58 patients (14.5%) and moderate to severe in 9 patients (2.2%). There was no fibrosis in 92 patients (23.1%), periportal fibrosis in 150 patients (37.6%), septal fibrosis in 123 patients (30.8%), and biliary cirrhosis in 34 patients (8.5%). Steatosis (≥ 5%) was not associated with PHLF (odds ratio [OR] 1.36; 95% confidence interval [CI] 0.69–2.68) or 90-day mortality (OR 1.22; 95% CI 0.62–2.39). Neither was fibrosis (i.e., periportal, septal, or biliary cirrhosis) associated with PHLF (OR 0.76; 95% CI 0.41–1.41) or 90-day mortality (OR 0.60; 95% CI 0.33–1.06). The independent risk factors for PHLF were preoperative cholangitis (OR 2.38; 95% CI 1. 36–4.17) and future liver remnant smaller than 40% (OR 2.40; 95% CI 1.31–4.38). The independent risk factors for 90-day mortality were age of 65 years or older (OR 2.40; 95% CI 1.36–4.23) and preoperative cholangitis (OR 2.25; 95% CI 1.30–3.87).ConclusionIn this study, no association could be demonstrated between hepatic steatosis or fibrosis and postoperative outcomes after resection of pCCA.

The Role of Immune Cells in Liver Regeneration

The liver is the only organ that can regenerate and regain its original tissue-to-body weight ratio within a short period of time after tissue loss. Insufficient liver regeneration in patients after partial hepatectomy or liver transplantation with partial liver grafts often leads to post-hepatectomy liver failure or small-for-size syndrome, respectively. Enhancing liver regeneration after liver injury might improve outcomes and increase patient survival. Liver regeneration comprises hepatocyte proliferation, and hepatic progenitor cell expansion and differentiation into hepatocytes. The immune system is intensively involved in liver regeneration. The current review provides a comprehensive overview of the diverse roles played by immune cells in liver regeneration. Macrophages, neutrophils, eosinophils, basophils, mast cells, platelets, dendritic cells, type 1 innate lymphoid cells, B cells, and T cells are implicated in promoting liver regeneration, while natural killer cells and overactivated natural killer T cells are supposed to inhibit hepatocyte proliferation. We also highlight the predominant underlying mechanisms mediated by immune cells, which may contribute to the development of novel strategies for promoting liver regeneration in patients with liver diseases.

Intravoxel incoherent motion diffusion weighted imaging for preoperative evaluation of liver regeneration after hepatectomy in hepatocellular carcinoma.

To explore whether intravoxel incoherent motion (IVIM) parameters could evaluate liver regeneration preoperatively. A total of 175 HCC patients were initially recruited. The apparent diffusion coefficient, true diffusion coefficient (D), pseudodiffusion coefficient (D*), pseudodiffusion fraction (f), diffusion distribution coefficient, and diffusion heterogeneity index (Alpha) were measured by two independent radiologists. Spearman's correlation test was used to assess correlations between IVIM parameters and the regeneration index (RI), calculated as 100% × (the volume of the postoperative remnant liver - the volume of the preoperative remnant liver) / the volume of the preoperative remnant liver. Multivariate linear regression analyses were used to identify the factors for RI. Finally, 54 HCC patients (45 men and 9 women, mean age 51.26 ± 10.41 years) were retrospectively analyzed. The intraclass correlation coefficient ranged from 0.842 to 0.918. In all patients, fibrosis stage was reclassified as F0-1 (n = 10), F2-3 (n = 26), and F4 (n = 18) using the METAVIR system. Spearman correlation test showed D* (r = 0.303, p = 0.026) was associated with RI; however, multivariate analysis showed that only D value was a significant predictor (p< 0.05) of RI. D and D*showed moderate correlations with fibrosis stage (r = -0.361, p= 0.007; r = -0.457, p = 0.001). Fibrosis stage showed a negative correlation with RI (r = -0.263, p= 0.015). In the 29 patients who underwent minor hepatectomy, only the D value showed a positive association (p< 0.05) with RI, and a negative correlation with fibrosis stage (r = -0.360, p= 0.018). However, in the 25 patients who underwent major hepatectomy, no IVIM parameters were associated with RI (p > 0.05). The D and D* values, especially the D value, may be reliable preoperative predictors of liver regeneration. • The D and D* values, especially the D value, derived from IVIM diffusion-weighted imaging may be useful markers for the preoperative prediction of liver regeneration in patients with HCC. • The D and D* values derived from IVIM diffusion-weighted imaging show significant negative correlations with fibrosis, an important predictor of liver regeneration. • No IVIM parameters were associated with liver regeneration in patients who underwent major hepatectomy, but the D value was a significant predictor of liver regeneration in patients who underwent minor hepatectomy.

Preoperative evaluation of liver regeneration following hepatectomy in hepatocellular carcinoma using magnetic resonance elastography.

For patients with hepatocellular carcinoma (HCC) undergoing hepatectomy, insufficient remnant liver regenerative capacity can lead to liver failure. The aim of this study was to evaluate the potential role of magnetic resonance elastography (MRE) for the preoperative prediction of liver regeneration in patients with HCC after partial hepatectomy (PH). A total of 54 patients with HCC undergoing MRE prior to PH were retrospectively included. The total functional liver, volume of preoperative future liver remnant (LVpre), and volume of postoperative liver remnant (LVpost), respectively, were measured, and the regeneration index (RI) and parenchymal hepatic resection rate (PHRR) were manually calculated. Univariate and multivariate logistic regression analyses were conducted to identify factors associated with a high RI, and receiver operating characteristic (ROC) curves were employed to evaluate the diagnostic performance of the liver stiffness (LS) values. Patients were classified into three subgroups based on the value of PHRR: low PHRR (<30%), intermediate PHRR (30-50%), and high PHRR (>50%). Subsequently, Spearman correlation analysis was used to investigate the relationship between LS values and RI in the subgroups. Multivariable analysis revealed a low LS value was associated with greater odds of a high RI [odds ratio (OR), 0.049; 95% confidence interval (CI): 0.002 to 0.980]. An optimal cutoff value of 3.30 kPa was used to divide all patients into a low RI group and a high RI group with an area under the curve (AUC) value of 0.882 (95% CI: 0.767 to 0.996). A significant negative relationship between RI and LS values (r=-0.799; P<0.001) was observed in the intermediate PHRR subgroup. The LS values based on MRE may serve as a potential preoperative predictor of liver regeneration for patients with HCC undergoing PH.

Impact of Perihepatic Adhesions on Liver Regeneration during Two-Stage Hepatectomy for Unresectable Colorectal Liver Metastases: Results from the Sepra-C2T Prospective Trial

Introduction: Two-stage hepatectomy (TSH) is an effective treatment for unresectable colorectal liver metastasis (CLM). Insufficient hepatic growth may prevent from performing the second stage. Peri-hepatic adhesions are frequent after the first hepatectomy. Incidence and severity of adhesions can be prevented by anti-adhesion barriers. The objective of our study was to investigate the impact of post-operative peri-hepatic adhesions on liver regeneration in patients who underwent TSH for unresectable CLM.

Predictive implication for liver regeneration by transient elastography in patients with major hepatectomy of perihilar cholangiocarcinoma

There are many studies regarding postoperative liver regeneration after major hepatectomy related to posthepatectomy liver failure (PHLF). However, there are no study which focused on liver fibrosis measured by transient elastography and liver regeneration. Therefore, we aimed to evaluate the correlation between transient elastography and liver regeneration in patients who underwent surgery for perihilar cholangiocarcinoma (PHCC). Patients who underwent major hepatectomy for PHCC with curative intent between 2016 and 2020 were included in the study. Patients were divided into groups by the value of liver stiffness measured by transient liver elastography and the cutoff values for severity of fibrosis were derived from the study by Tsochatzis et al. Liver volumes were compared between preoperative and postoperative day 5 CT scan. Of the 45 patients who underwent surgery for PHCC, F1 group was consisted of 23 (51.1%) patients, F2 group 10 (22.2%), F3 group 9 (20.0%), and F4 group 3 (6.7%) patients. The patients were divided into 2 groups, F1 and F2 as Group A and F3 and F4 as Group B. The ICG R 15 value was 14.7 ± 6.6 in Group A and 20.3 ± 9.9 in Group B (p = 0.034). The mean value of liver volume increase rate of each group was 42.3% ± 30.9% in Group A, and 37.4% ± 24.6% in Group B (p = 0.622). This study suggests that liver fibrosis has a tendency to be related with less liver regeneration but without clinical significance. However, transient elastography could be used as one of the useful predictor reference for liver regeneration related to PHLF.

Bile Salt and FGF19 Signaling in the Early Phase of Human Liver Regeneration.

The involvement of bile salt–fibroblast growth factor 19 (FGF19) signaling in human liver regeneration (LR) is not well studied. Therefore, we studied aspects of bile salt–FGF19 signaling shortly after liver resection in patients. We compared plasma bile salt and FGF19 levels in arterial, portal and hepatic venous blood, calculated venous‐arterial differences (ΔVA), and determined hepatic transcript levels on two intra‐operative time points: before (< 1 hour) and immediately after (> 2‐3 hours) liver resection (i.e., following surgery). Postoperative bile salt and FGF19 levels were assessed on days 1, 2, and 3. LR was studied by computed tomography (CT)–liver volumetry. Following surgery, the liver, arterial, and portal bile salt levels were elevated (P < 0.05). Furthermore, an increased amount of bile salts was released in portal blood and extracted by the remnant liver (P < 0.05). Postoperatively, bile salt levels were elevated from day 1 onward (P < 0.001). For FGF19, intra‐operative or postoperative changes of ΔVA or plasma levels were not observed. The bile salt–homeostatic regulator farnesoid X receptor (FXR) was markedly up‐regulated following surgery (P < 0.001). Cell‐cycle re‐entry priming factors (interleukin 6 [IL‐6], signal transducer and activator of transcription 3 [STAT3], and cJUN) were up‐regulated following surgery and were positively correlated with FXR expression (P < 0.05). Postoperative hyperbilirubinemia was preceded by postsurgery low FXR and high Na+/Taurocholate cotransporting polypeptide (NTCP) expression in the remnant liver coupled with higher liver bile salt content (P < 0.05). Finally, bile salt levels on postoperative day 1 were an independent predictor of LR (P < 0.05). Conclusion: Systemic, portal, and liver bile salt levels are rapidly elevated after liver resection. Postoperative bile salts were positively associated with liver volume gain. In the studied time frame, FGF19 levels remained unaltered, suggesting that FGF19 plays a minor role in human LR. These findings indicate a more relevant role of bile salts in human LR.

Single-Cell RNA-seq Reveals Angiotensin-Converting Enzyme 2 and Transmembrane Serine Protease 2 Expression in TROP2+ Liver Progenitor Cells: Implications in Coronavirus Disease 2019-Associated Liver Dysfunction.

The recent coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2. COVID-19 was first reported in China (December 2019) and is now prevalent across the globe. Entry of severe acute respiratory syndrome coronavirus 2 into mammalian cells requires the binding of viral Spike (S) proteins to the angiotensin-converting enzyme 2 receptor. Once entered, the S protein is primed by a specialized serine protease, transmembrane serine protease 2 in the host cell. Importantly, besides the respiratory symptoms that are consistent with other common respiratory virus infections when patients become viremic, a significant number of COVID-19 patients also develop liver comorbidities. We explored whether a specific target cell-type in the mammalian liver could be implicated in disease pathophysiology other than the general deleterious response to cytokine storms. Here, we used single-cell RNA-seq to survey the human liver and identified potentially implicated liver cell-type for viral ingress. We analyzed ~300,000 single cells across five different (i.e., human fetal, healthy, cirrhotic, tumor, and adjacent normal) liver tissue types. This study reports on the co-expression of angiotensin-converting enzyme 2 and transmembrane serine protease 2 in a TROP2+ liver progenitor population. Importantly, we detected enrichment of this cell population in the cirrhotic liver when compared with tumor tissue. These results indicated that in COVID-19-associated liver dysfunction and cell death, a viral infection of TROP2+ progenitors in the liver might significantly impair liver regeneration in patients with liver cirrhosis.

Role of alpha-fetoprotein in prognostic evaluation of patients with liver failure

China is a big country with liver diseases, and various hepatitis viruses, drug poisons, and alcohol can cause liver injury and even liver failure. The key to the prognosis of patients with liver failure is liver self-repair and regeneration. Alpha-fetoprotein (AFP) has been extensively studied as a tumor marker in liver cancer, but its role in liver regeneration in patients with liver failure awaits further studies. This article summarizes the basic research on AFP in liver regeneration and the clinical research on AFP in acute liver failure and acute-on-chronic liver failure (ACLF), as well as the previous research findings of our group that AFP is an important prognostic index and regeneration factor for liver regeneration after hepatitis B virus-related ACLF. The analysis shows that further studies on the role of AFP in the prognosis of various types of liver failure and the mechanism of liver regeneration will help deepen our understanding of AFP and liver regeneration, thereby providing new ideas and methods for the clinical diagnosis, treatment, and prognostic evaluation of patients with various types of liver failure.

Still 'dwelling in the possibility' - critical update on stem cell therapy for acute on chronic liver failure.

Stem cells therapy could improve survival in patients with liver failure. Studies on stem cell therapy and related growth factors in decompensated cirrhosis has been on the forefront but has shown heterogenous results. Recent high-quality studies have shown a lack of efficacy and safety. Patients with acute-on-chronic liver failure (ACLF) are a unique group with high mortality in the short-term associated with rapid onset extrahepatic organ failures. In these patients, there is an urgent need to identify treatments that can improve liver cell function and mass, prevent sepsis/organ failure, ameliorate systemic inflammation, and increase transplant-free survival. Stem cells are a novel treatment in ACLF but with unclear efficacy and safety. In this narrative review, we discuss the basics of liver regeneration in patients with ACLF and update current clinical status of stem cell use in patients with ACLF for improving our understanding of future directions.

Pathophysiology of bile acids affects liver regeneration in patients undergoing liver resection

Pathophysiology of bile acids affects liver regeneration in patients undergoing liver resection

Loss of Integrin αvβ8 in Murine Hepatocytes Accelerates Liver Regeneration

Recent fate-mapping studies in mice have provided substantial evidence that mature adult hepatocytes are a major source of new hepatocytes after liver injury. In other systems, integrin αvβ8 has a major role in activating transforming growth factor (TGF)-β, a potent inhibitor of hepatocyte proliferation. We hypothesized that depletion of hepatocyte integrin αvβ8 would increase hepatocyte proliferation and accelerate liver regeneration after injury. Using Itgb8flox/flox;Alb-Cre mice to deplete hepatocyte αvβ8, after partial hepatectomy, hepatocyte proliferation and liver-to-body weight ratio were significantly increased in Itgb8flox/flox;Alb-Cre mice compared with control mice. Antibody-mediated blockade of hepatocyte αvβ8 in vitro, with assessment of TGF-β signaling pathways by real-time quantitative PCR array, supported the hypothesis that integrin αvβ8 inhibition alters hepatocyte TGF-β signaling toward a pro-regenerative phenotype. A diethylnitrosamine-induced model of hepatocellular carcinoma, used to examine the possibility that this pro-proliferative phenotype might be oncogenic, revealed no difference in either tumor number or size between Itgb8flox/flox;Alb-Cre and control mice. Immunohistochemistry for integrin αvβ8 in healthy and injured human liver demonstrated that human hepatocytes express integrin αvβ8. Depletion of hepatocyte integrin αvβ8 results in increased hepatocyte proliferation and accelerated liver regeneration after partial hepatectomy in mice. These data demonstrate that targeting integrin αvβ8 may represent a promising therapeutic strategy to drive liver regeneration in patients with a broad range of liver diseases.

Volumetric and Functional Regeneration of Remnant Liver after Hepatectomy

BackgroundPost-hepatectomy liver regeneration is of great interest to liver surgeons, and understanding the process of regeneration could contribute to increasing the safety of hepatectomies and improving prognoses. MethodsFive hundred thirty-eight patients who underwent hepatectomy were retrospectively analyzed. Postoperative outcomes were evaluated, with a focus on the effects of portal vein resection and resected liver volume on remnant liver regeneration in patients with liver tumors. Remnant liver volumes (RLVs) and laboratory data were measured postoperatively using multidetector computed tomography on day 7 and months 1, 2, 5, 12, and 24 after the operation. ResultsLiver regeneration speed peaked at 1 week postoperatively and gradually decreased. Regeneration with large resections was longer than that with small resections, with the remnant liver regeneration rate being significantly lower in the former at all time points. Remnant liver regeneration plateaued around 5 months postoperatively, when regeneration is almost complete. Up to 1 month postoperatively, laboratory data were significantly worse when more portal veins was resected. After 2 months postoperatively, these data recovered to near normal levels. ConclusionThe speed and rate of remnant liver regeneration primarily showed a strong correlation with the number of resected portal veins and the amount of removed liver parenchyma. The larger the resection ratio, the longer it took the liver to regenerate. We confirmed that recovery of the liver’s functional aspects accompanies recovery of the RLV.

Serial Assessment of Growth Factors Associated with Liver Regeneration in Patients Operated with Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy

Background: There is limited knowledge about the mechanisms behind the unparalleled growth of the future liver remnant (FLR) linked to associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). In this study, liver regenerative markers were examined in patients subjected to ALPPS. Methods: Ten patients with colorectal liver metastases treated with neoadjuvant chemotherapy and ALPPS were included. Plasma was sampled at 6 time points and biopsies from both liver lobes were collected at both stages of ALPPS. The levels of interleukin (IL)-6, hepatocyte growth factor (HGF), tumor necrosis factor-α, epidermal growth factor, and vascular endothelial growth factor in plasma were measured at each time point. Expression of mRNA for markers of proliferation and apoptosis was studied in the biopsies from both liver lobes taken at both stages. Results: ALPPS resulted in a peak of IL-6 after stage 1 (p = 0.004), which decreased rapidly and did not increase again after stage 2. HGF also increased after stage 1 (p = 0.048), and the HGF levels correlated significantly with the degree of growth of the FLR before stage 2 (p = 0.02, r² = 0.47). There was a correlation between peak levels of IL-6 and HGF (p = 0.03, r² = 0.84). Conclusions: IL-6 and HGF seem to be early mediators of hypertrophy after stage 1 in the ALPPS procedure. The peak HGF plasma level correlates with the degree of FLR growth in patients subjected to ALPPS.

Liver dual arterial blood supply maintains liver regeneration: Analysis of signaling pathways in rats.

Liver dual arterial blood supply (LDABS) could increase blood supply to the liver and maintain normal liver regeneration in patients with compromised portal vein. The current study attempted to examine the underlying molecular mechanisms. Male Sprague-Dawley rats randomly received partial hepatectomy (PH) alone or PH followed by LDABS. Liver regeneration was assessed by histological examination, liver function and liver regeneration rate (LRR). Whole-genome oligo microarray analysis was used to compare gene expression profile between rats receiving PH and rats receiving PH plus LDABS. Key genes identification was validated using a MAPK signaling polymerase chain reaction (PCR) array. The extent of liver regeneration in rats receiving PH plus LDABS was comparable to that in rats receiving PH alone. The differentially expressed genes were enriched in 12 signaling pathways in two groups. MAPK signaling pathway, NF-kappa B signaling pathway, and Toll-like receptor signaling pathway were involved in LDABS-mediated liver regeneration, with Retinoblastoma 1 (Rb1), Cyclin D1, Cyclin-dependent kinase 4, Mitogen-activated protein kinase 10 (Mapk10) and CAMP responsive element binding protein 1 genes in the initiation phase, Kirsten rat sarcoma viral oncogene homolog (Kras), tumor protein 53, MYC proto-oncogene, BHLH transcription factor, Cyclin E1 and Heat shock protein family B (small) member 1 genes in the proliferation phase, Kras, Rb1, Jun proto-oncogene, AP-1 transcription factor subunit, Cyclin D2 and Mapk10 genes in the termination phase were identified as key genes in LDABS-mediated liver regeneration using MAPK signaling PCR array analysis.

Advanced oxidation protein products induce S-phase arrest of hepatocytes via the ROS-dependent, β-catenin-CDK2-mediated pathway

Liver regeneration has important clinical importance in the setting of partial hepatectomy (PH). Following PH, quiescent hepatocytes can reenter cell cycle to restore liver mass. Hepatocyte cell cycle progression, as the basic motivations of liver regeneration, can be disrupted by multiple pathological factors such as oxidative stress. This study aimed to evaluate the role of advanced oxidation protein products (AOPP) in S-phase arrest in hepatocytes. Serum AOPP level were measured during the perioperative period of PH in 33 patients with hepatocellular carcinoma (HCC). Normal Sprague Dawley rats, human and murine liver cell line (HL-7702 and AML-12) were challenged with AOPP prepared by incubation of rat serum albumin (RSA) with hypochlorous acid, and the effect of AOPP on hepatocytes cell cycle progression and liver regeneration was studied after PH. AOPP levels were increased following partial hepatectomy (PH) in patients with primary liver cancer. AOPP treatment impaired liver regeneration in rats following 70% partial hepatectomy. S-phase arrest was induced by AOPP administration in hepatocytes derived from the remnant liver at controlled times following partial hepatectomy in rats, and in HL-7702 and AML-12 cells. The effect of AOPP on hepatocyte S phase arrest was mainly mediated by a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent reactive oxygen species (ROS) generation, downregulation of downstream β-catenin signaling and decreased cyclin-dependent kinase 2 (CDK2) expression, which inhibited S-phase progression in hepatocytes. This study provides preliminary evidence that AOPP can induce S-phase arrest in hepatocytes via the ROS-dependent, β-catenin-CDK2-mediated pathway. These findings suggest a novel pathogenic role of AOPP contributing to the impaired liver regeneration and may provide the basis for developing new strategies to improve liver regeneration in patients undergoing PH.

Modulation of liver regeneration via myeloid PTEN deficiency

Molecular mechanisms that modulate liver regeneration are of critical importance for a number of hepatic disorders. Kupffer cells and natural killer (NK) cells are two cell subsets indispensable for liver regeneration. We have focused on these two populations and, in particular, the interplay between them. Importantly, we demonstrate that deletion of the myeloid phosphatase and tensin homolog on chromosome 10 (PTEN) leading to an M2-like polarization of Kupffer cells, which results in decreased activation of NK cells. In addition, PTEN-deficient Kupffer cells secrete additional factors that facilitate the proliferation of hepatocytes. In conclusion, PTEN is critical for inhibiting M2-like polarization of Kupffer cells after partial hepatectomy, resulting in NK cell activation and thus the inhibition of liver regeneration. Furthermore, PTEN reduces growth factor secretion by Kupffer cells. Our results suggest that targeting PTEN on Kupffer cells may be useful in altering liver regeneration in patients undergoing liver resection.

Human Muse Cells, Nontumorigenic Phiripotent-Like Stem Cells, Have Liver Regeneration Capacity through Specific Homing and Cell Replacement in a Mouse Model of Liver Fibrosis

Muse cells, a novel type of nontumorigenic pluripotent-like stem cells, reside in the bone marrow, skin, and adipose tissue and are collectable as cells positive for pluripotent surface marker SSEA-3. They are able to differentiate into cells representative of all three germ layers. The capacity of intravenously injected human bone marrow-derived Muse cells to repair an immunodeficient mouse model of liver fibrosis was evaluated in this study. The cells exhibited the ability to spontaneously differentiate into hepatoblast/hepatocyte lineage cells in vitro. They demonstrated a high migration capacity toward the serum and liver section of carbon tetrachloride-treated mice in vitro. In vivo, they specifically accumulated in the liver, but not in other organs except, to a lesser extent, in the lungs at 2 weeks after intravenous injection in the liver fibrosis model. After homing, Muse cells spontaneously differentiated in vivo into HepPar-1 (71.1±15.2%), human albumin (54.3±8.2%), and anti-trypsin (47.9±4.6%)-positive cells without fusing with host hepatocytes, and expressed mature functional markers such as human CYP1A2 and human Glc-6-Pase at 8 weeks after injection. Recovery in serum, total bilirubin, and albumin and significant attenuation of fibrosis were recognized with statistical differences between the Muse cell-transplanted group and the control groups, which received the vehicle or the same number of a non-Muse cell population of MSCs (MSCs in which Muse cells were eliminated). Thus, unlike ESCs and iPSCs, Muse cells are unique in their efficient migration and integration into the damaged liver after intravenous injection, nontumorigenicity, and spontaneous differentiation into hepatocytes, rendering induction into hepatocytes prior to transplantation unnecessary. They may repair liver fibrosis by two simple steps: expansion after collection from the bone marrow and intravenous injection. A therapeutic strategy such as this is feasible and may provide significant advancements toward liver regeneration in patients with liver disease.

Administration of multipotent mesenchymal stromal cells restores liver regeneration and improves liver function in obese mice with hepatic steatosis after partial hepatectomy

BackgroundThe liver has the remarkable capacity to regenerate in order to compensate for lost or damaged hepatic tissue. However, pre-existing pathological abnormalities, such as hepatic steatosis (HS), inhibits the endogenous regenerative process, becoming an obstacle for liver surgery and living donor transplantation.Recent evidence indicates that multipotent mesenchymal stromal cells (MSCs) administration can improve hepatic function and increase the potential for liver regeneration in patients with liver damage. Since HS is the most common form of chronic hepatic illness, in this study we evaluated the role of MSCs in liver regeneration in an animal model of severe HS with impaired liver regeneration.MethodsC57BL/6 mice were fed with a regular diet (normal mice) or with a high-fat diet (obese mice) to induce HS. After 30 weeks of diet exposure, 70% hepatectomy (Hpx) was performed and normal and obese mice were divided into two groups that received 5 × 105 MSCs or vehicle via the tail vein immediately after Hpx.ResultsWe confirmed a significant inhibition of hepatic regeneration when liver steatosis was present, while the hepatic regenerative response was promoted by infusion of MSCs. Specifically, MSC administration improved the hepatocyte proliferative response, PCNA-labeling index, DNA synthesis, liver function, and also reduced the number of apoptotic hepatocytes.These effects may be associated to the paracrine secretion of trophic factors by MSCs and the hepatic upregulation of key cytokines and growth factors relevant for cell proliferation, which ultimately improves the survival rate of the mice.ConclusionsMSCs represent a promising therapeutic strategy to improve liver regeneration in patients with HS as well as for increasing the number of donor organs available for transplantation.