Identification of Dhx15 as a Major Regulator of Liver Development, Regeneration, and Tumor Growth in Zebrafish and Mice.

RNA helicase DHX15 plays a significant role in vasculature development and lung metastasis in vertebrates. In addition, several studies have demonstrated the overexpression of DHX15 in the context of hepatocellular carcinoma. Therefore, we hypothesized that this helicase may play a significant role in liver regeneration, physiology, and pathology. Dhx15 gene deficiency was generated by CRISPR/Cas9 in zebrafish and by TALEN-RNA in mice. AUM Antisense-Oligonucleotides were used to silence Dhx15 in wild-type mice. The hepatocellular carcinoma tumor induction model was generated by subcutaneous injection of Hepa 1-6 cells. Homozygous Dhx15 gene deficiency was lethal in zebrafish and mouse embryos. Dhx15 gene deficiency impaired liver organogenesis in zebrafish embryos and liver regeneration after partial hepatectomy in mice. Also, heterozygous mice presented decreased number and size of liver metastasis after Hepa 1-6 cells injection compared to wild-type mice. Dhx15 gene silencing with AUM Antisense-Oligonucleotides in wild-type mice resulted in 80% reduced expression in the liver and a significant reduction in other major organs. In addition, Dhx15 gene silencing significantly hindered primary tumor growth in the hepatocellular carcinoma experimental model. Regarding the potential use of DHX15 as a diagnostic marker for liver disease, patients with hepatocellular carcinoma showed increased levels of DHX15 in blood samples compared with subjects without hepatic affectation. In conclusion, Dhx15 is a key regulator of liver physiology and organogenesis, is increased in the blood of cirrhotic and hepatocellular carcinoma patients, and plays a key role in controlling hepatocellular carcinoma tumor growth and expansion in experimental models.

Antagonizing Activin A/p15INK4b Signaling as Therapeutic Strategy for Liver Disease.

BACKGROUND/AIM: Activin A is involved in the pathogenesis of human liver diseases, but its therapeutic targeting is not fully explored. Here, we tested the effect of novel, highly specific small-molecule-based activin A antagonists (NUCC-474/555) in improving liver regeneration following partial hepatectomy and halting fibrosis progression in models of chronic liver diseases (CLDs). METHODS: Cell toxicity of antagonists was determined in rat hepatocytes and Huh-7 cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay. Hepatocytes and hepatic stellate cells (HSCs) were treated with activin A and NUCC-555 and analyzed by reverse transcription-polymerase chain reaction and immunohistochemistry. Partial hepatectomized Fisher (F)344 rats were treated with NUCC-555, and bromodeoxyuridine (BrdU) incorporation was determined at 18/24/36/120/240 h. NUCC-555 was administered into thioacetamide- or carbon tetrachloride-treated F344 rats or C57BL/6 mice, and the fibrosis progression was studied. RESULTS: NUCC-474 showed higher cytotoxicity in cultured hepatic cells; therefore, NUCC-555 was used in subsequent studies. Activin A-stimulated overexpression of cell cycle-/senescence-related genes (e.g., p15INK4b, DEC1, Glb1) was near-completely reversed by NUCC-555 in hepatocytes. Activin A-mediated HSC activation was blocked by NUCC-555. In partial hepatectomized rats, antagonizing activin A signaling resulted in a 1.9-fold and 2.3-fold increase in BrdU+ cells at 18 and 24 h, respectively. Administration of NUCC-555 in rats and mice with progressing fibrosis significantly reduced collagen accumulation (7.9-fold), HSC activation indicated by reduced alpha smooth muscle actin+ and vimentin+ cells, and serum aminotransferase activity. CONCLUSIONS: Our studies demonstrate that activin A antagonist NUCC-555 promotes liver regeneration and halts fibrosis progression in CLD models, suggesting that blocking activin A signaling may represent a new approach to treating people with CLD.

NIBR-LTSi is a selective LATS kinase inhibitor activating YAP signaling and expanding tissue stem cells in vitro and in vivo.

The YAP/Hippo pathway is an organ growth and size regulation rheostat safeguarding multiple tissue stem cell compartments. LATS kinases phosphorylate and thereby inactivate YAP, thus representing a potential direct drug target for promoting tissue regeneration. Here, we report the identification and characterization of the selective small-molecule LATS kinase inhibitor NIBR-LTSi. NIBR-LTSi activates YAP signaling, shows good oral bioavailability, and expands organoids derived from several mouse and human tissues. In tissue stem cells, NIBR-LTSi promotes proliferation, maintains stemness, and blocks differentiation in vitro and in vivo. NIBR-LTSi accelerates liver regeneration following extended hepatectomy in mice. However, increased proliferation and cell dedifferentiation in multiple organs prevent prolonged systemic LATS inhibition, thus limiting potential therapeutic benefit. Together, we report a selective LATS kinase inhibitor agonizing YAP signaling and promoting tissue regeneration in vitro and in vivo, enabling future research on the regenerative potential of the YAP/Hippo pathway.

Improvement in aged liver regeneration using cell transplantation with chemically induced liver progenitors.

BACKGROUND: A decrease in the regenerative capacity of age-damaged liver tissue has been reported. Liver progenitor cells may play an important role in the regeneration of injured livers. In the present study we aimed to investigate improvements in the regenerative capacity of age-damaged livers using chemically induced liver progenitors (CLiPs) derived from mature hepatocytes. METHODS: Old (>90 weeks) and young (<20 weeks) mice underwent 70% hepatectomy, with or without trans-splenic CLiP administration. The residual liver/bodyweight (LW/BW) ratio was measured on postoperative days 1 and 7, and changes in liver regeneration and histology were evaluated. RESULTS: At 7 days post-hepatectomy, LW/BW ratios were significantly better in CLiP-treated old mice than in untreated old mice (p = .02). By contrast, no effect of CLiP transplantation was observed in young mice (p = .62). Immunofluorescence staining of liver tissue after CLiP administration showed an increase in Ki67-positive cells (p < .01). Flow cytometry analysis of green fluorescent protein-labeled CLiPs indicated that transplanted CLiPs differentiated into mature hepatocytes and were present in the recipient liver. CONCLUSIONS: CLiP transplantation appears to ameliorate the age-related decline in liver regeneration in mice.

Sarcopenia does not affect liver regeneration and postoperative course after a major hepatectomy. A prospective study on 125 patients using CT volumetry and HIDA scintigraphy.

BACKGROUND & OBJECTIVES: Sarcopenia is a morbi-mortality risk factor in digestive surgery, though its impact after major hepatectomy (MH) remains unknown. This prospective pilot study investigated whether volume and function of a regenerating liver is influenced by body composition. METHODS: From 2011 to 2016, 125 consecutive patients had computed tomography and 99mTc-labelled-mebrofenin SPECT-scintigraphy before and after MH at day 7 and 1 month for measurements of liver volumes and functions. L3 vertebra muscle mass identified sarcopenia. Primary endpoint was the impact of sarcopenia on regeneration capacities (i.e. volume/function changes and post-hepatectomy liver failure (PHLF) rate). Secondary endpoint was 3-month morbi-mortality. RESULTS: Sarcopenic patients (SP; N = 69) were significantly older than non-sarcopenic (NSP), with lower BMI and more malignancies, but with comparable liver function/volume at baseline. Postoperatively, SP showed higher rates of ISGLS_PHLF (24.6 % vs 10.9 %; p = 0.05) but with comparable rates of severe morbidity (23.2 % vs 16.4 %; p = 0.35), overall (8.7 % vs 3.6 %; p = 0.3) and PHLF-related mortality (8,7 % vs 1.8 %; p = 0.075). After matching on the extent of resection or using propensity score, regeneration and PHLF rates were similar. CONCLUSION: This prospective study using first sequential SPECT-scintigraphy showed that sarcopenia by itself does not affect liver regeneration capacities and short-term postoperative course after MH.

Hybrid Bioactive Hydrogel Promotes Liver Regeneration through the Activation of Kupffer Cells and ECM Remodeling After Partial Hepatectomy.

Partial hepatectomy is an essential surgical technique used to treat advanced liver diseases such as liver tumors, as well as for performing liver transplants from living donors. However, postoperative complications such as bleeding, abdominal adhesions, wound infections, and inadequate liver regeneration pose significant challenges and increase morbidity and mortality rates. A self-repairing mixed hydrogel (O5H2/Cu2+/SCCK), containing stem cell derived cytokine (SCCK) derived from human umbilical cord mesenchymal stem cells (HUMSCs) treated with the traditional Chinese remedy Tanshinone IIA (TSA), is developed. This SCCK, in conjunction with O5H2, demonstrates remarkable effects on Kupffer cell activation and extracellular matrix (ECM) remodeling. This leads to the secretion of critical growth factors promoting enhanced proliferation of hepatocytes and endothelial cells, thereby facilitating liver regeneration and repair after partial hepatectomy. Furthermore, the hydrogel, featuring macrophage-regulating properties, effectively mitigates inflammation and oxidative stress damage in the incision area, creating an optimal environment for postoperative liver regeneration. The injectability and strong adhesion of the hydrogel enables rapid hemostasis at the incision site, while its physical barrier function prevents postoperative abdominal adhesions. Furthermore, the hydrogel's incorporation of Cu2+ provides comprehensive antibacterial effects, protecting against a wide range of bacteria types and reducing the chances of infections after surgery.

Role of Fibrinogen-like Protein 1 in Tumor Recurrence Following Hepatectomy.

Partial hepatectomy is a first-line treatment for hepatocellular carcinoma. Within 2 weeks following partial hepatectomy, specific molecular pathways are activated to promote liver regeneration. Nevertheless, residual microtumors may also exploit these pathways to reappear and metastasize. Therapeutically targeting molecules that are differentially regulated between normal cells and malignancies, such as fibrinogen-like protein 1 (FGL1), appears to be an effective approach. The potential functions of FGL1 in both regenerative and malignant cells are discussed within the ambit of this review. While FGL1 is normally elevated in regenerative hepatocytes, it is normally downregulated in malignant cells. Hepatectomy does indeed upregulate FGL1 by increasing the release of transcription factors that promote FGL1, including HNF-1α and STAT3, and inflammatory effectors, such as TGF-ß and IL6. This, in turn, stimulates certain proliferative pathways, including EGFR/Src/ERK. Hepatectomy alters the phase transition of highly differentiated hepatocytes from G0 to G1, thereby transforming susceptible cells into cancerous ones. Activation of the PI3K/Akt/mTOR pathway by FGL1 allele loss on chromosome 8, a tumor suppressor area, may also cause hepatocellular carcinoma. Interestingly, FGL1 is specifically expressed in the liver via HNF-1α histone acetylase activity, which triggers lipid metabolic reprogramming in malignancies. FGL1 might also be involved in other carcinogenesis processes such as hypoxia, epithelial-mesenchymal transition, immunosuppression, and sorafenib-mediated drug resistance. This study highlights a research gap in these disciplines and the necessity for additional research on FGL1 function in the described processes.

PFKFB3-mediated glycolysis in hepatic stellate cells promotes liver regeneration.

Hepatic stellate cells (HSCs) perform a significant function in liver regeneration (LR) by becoming active. We propose to investigate if activated HSCs enhance glycolysis via PFKFB3, an essential glycolytic regulator, and whether targeting this pathway could be beneficial for LR. The liver and isolated HSCs of mice subjected to 2/3 partial hepatectomy (PHx) exhibited a significant rise in PFKFB3 expression, as indicated by quantitative RT-PCR analyses and Western blotting. Also, the primary HSCs of mice subjected to PHx have a significant elevation of the glycolysis level. Knocking down PFKFB3 significantly diminished the enhancement of glycolysis by PDGF in human LX2 cells. The hepatocyte proliferation in mice treated with PHx was almost completely prevented when the PFKFB3 inhibitor 3PO was administered, emerging that PFKFB3 is essential in LR. Furthermore, there was a decline in mRNA expression of immediate early genes and proinflammatory cytokines. In terms of mechanism, both the p38 MAP kinase and ERK1/2 phosphorylation in LO2 cells and LO2 proliferation were significantly reduced by the conditioned medium (CM) obtained from LX2 cells with either PFKFB3 knockdown or inhibition. Compared to the control group, isolated hepatocytes from 3PO-treated mice showed decreased p38 MAP kinase and ERK1/2 phosphorylation and proliferation. Thus, LR after PHx involves the activation of PFKFB3 in HSCs, which enhances glycolysis and promotes lactate production, thereby facilitating hepatocyte proliferation via the p38/ERK MAPK signaling pathway.

A p21-ATD mouse model for monitoring and eliminating senescent cells and its application in liver regeneration post injury.

Cellular senescence associates with pathological aging and tissue dysfunctions. Studies utilizing mouse models for cell lineage tracings have emphasized the importance of senescence heterogeneity in different organs and cell types. Here, we constructed a p21- (Akaluc - tdTomato - Diphtheria Toxin Receptor [DTR]) (ATD) mouse model to specifically study the undefined mechanism for p21-expressing senescent cells in the aged and liver injury animals. The successful expressions of these genes enabled in vitro flow cytometric sorting, in vivo tracing, and elimination of p21-expressing senescent cells. During the natural aging process, p21-expressing cells were found in various tissues of p21-ATD mice. Eliminating p21-expressing cells in the aged p21-ATD mice recovered their multiple biological functions. p21-ATD/Fah-/- mice, bred from p21-ATD mice and fumarylacetoacetate hydrolase (Fah)-/- mice of liver injury, showed that the majority of their senescent hepatocytes were the phenotype of p21+ rather than p16+. Furthermore, eliminating the p21-expressing hepatocytes significantly promoted the engraftment of grafted hepatocytes and facilitated liver repopulation, resulting in significant recovery from liver injury. Our p21-ATD mouse model serves as an optimal model for studying the pattern and function of p21-expressing senescent cells under the physical and pathological conditions during aging.

New insights into the regulation of bile acids synthesis during the early stages of liver regeneration: A human and experimental study.

BACKGROUND AND AIMS: Liver regeneration is essential for the preservation of homeostasis and survival. Bile acids (BAs)-mediated signaling is necessary for liver regeneration, but BAs levels need to be carefully controlled to avoid hepatotoxicity. We studied the early response of the BAs-fibroblast growth factor 19 (FGF19) axis in healthy individuals undergoing hepatectomy for living donor liver transplant. We also evaluated BAs synthesis in mice upon partial hepatectomy (PH) and acute inflammation, focusing on the regulation of cytochrome-7A1 (CYP7A1), a key enzyme in BAs synthesis from cholesterol. METHODS: Serum was obtained from twelve human liver donors. Mice underwent 2/3-PH or sham-operation. Acute inflammation was induced with bacterial lipopolysaccharide (LPS) in mice fed control or antoxidant-supplemented diets. BAs and 7α-hydroxy-4-cholesten-3-one (C4) levels were measured by HPLC-MS/MS; serum FGF19 by ELISA. Gene expression and protein levels were analyzed by RT-qPCR and western-blot. RESULTS: Serum BAs levels increased after PH. In patients with more pronounced hypercholanemia, FGF19 concentrations transiently rose, while C4 levels (a readout of CYP7A1 activity) dropped 2 h post-resection in all cases. Serum BAs and C4 followed the same pattern in mice 1 h after PH, but C4 levels also dropped in sham-operated and LPS-treated animals, without marked changes in CYP7A1 protein levels. LPS-induced serum C4 decline was attenuated in mice fed an antioxidant-supplemented diet. CONCLUSIONS: In human liver regeneration FGF19 upregulation may constitute a protective response from BAs excess during liver regeneration. Our findings suggest the existence of post-translational mechanisms regulating CYP7A1 activity, and therefore BAs synthesis, independent from CYP7A1/Cyp7a1 gene transcription.

Angiotensin II type-2 receptor signaling facilitates liver injury repair and regeneration via inactivation of Hippo pathway.

The angiotensin II type 2 receptor (AT2R) is a well-established component of the renin-angiotensin system and is known to counteract classical activation of this system and protect against organ damage. Pharmacological activation of the AT2R has significant therapeutic benefits, including vasodilation, natriuresis, anti-inflammatory activity, and improved insulin sensitivity. However, the precise biological functions of the AT2R in maintaining homeostasis in liver tissue remain largely unexplored. In this study, we found that the AT2R facilitates liver repair and regeneration following acute injury by deactivating Hippo signaling and that interleukin-6 transcriptionally upregulates expression of the AT2R in hepatocytes through STAT3 acting as a transcription activator binding to promoter regions of the AT2R. Subsequently, elevated AT2R levels activate downstream signaling via heterotrimeric G protein Gα12/13-coupled signals to induce Yap activity, thereby contributing to repair and regeneration processes in the liver. Conversely, a deficiency in the AT2R attenuates regeneration of the liver while increasing susceptibility to acetaminophen-induced liver injury. Administration of an AT2R agonist significantly enhances the repair and regeneration capacity of injured liver tissue. Our findings suggest that the AT2R acts as an upstream regulator in the Hippo pathway and is a potential target in the treatment of liver damage.

JCAD deficiency delayed liver regenerative repair through the Hippo-YAP signalling pathway.

BACKGROUND AND AIMS: Liver regeneration retardation post partial hepatectomy (PH) is a common clinical problem after liver transplantation. Identification of key regulators in liver regeneration post PH may be beneficial for clinically improving the prognosis of patients after liver transplantation. This study aimed to clarify the function of junctional protein-associated with coronary artery disease (JCAD) in liver regeneration post PH and to reveal the underlying mechanisms. METHODS: JCAD knockout (JCAD-KO), liver-specific JCAD-KO (Jcad△Hep) mice and their control group were subjected to 70% PH. RNA sequencing was conducted to unravel the related signalling pathways. Primary hepatocytes from KO mice were treated with epidermal growth factor (EGF) to evaluate DNA replication. Fluorescent ubiquitination-based cell cycle indicator (FUCCI) live-imaging system was used to visualise the phases of cell cycle. RESULTS: Both global and liver-specific JCAD deficiency postponed liver regeneration after PH as indicated by reduced gene expression of cell cycle transition and DNA replication. Prolonged retention in G1 phase and failure to transition over the cell cycle checkpoint in JCAD-KO cell line was indicated by a FUCCI live-imaging system as well as pharmacologic blockage. JCAD replenishment by adenovirus reversed the impaired DNA synthesis in JCAD-KO primary hepatocyte in exposure to EGF, which was abrogated by a Yes-associated protein (YAP) inhibitor, verteporfin. Mechanistically, JCAD competed with large tumour suppressor 2 (LATS2) for WWC1 interaction, leading to LATS2 inhibition and thereafter YAP activation, and enhanced expression of cell cycle-associated genes. CONCLUSION: JCAD deficiency led to delayed regeneration after PH as a result of blockage in cell cycle progression through the Hippo-YAP signalling pathway. These findings uncovered novel functions of JCAD and suggested a potential strategy for improving graft growth and function post liver transplantation. KEY POINTS: JCAD deficiency leads to an impaired liver growth after PH due to cell division blockage. JCAD competes with LATS2 for WWC1 interaction, resulting in LATS2 inhibition, YAP activation and enhanced expression of cell cycle-associated genes. Delineation of JCADHippoYAP signalling pathway would facilitate to improve prognosis of acute liver failure and graft growth in living-donor liver transplantation.

HMGB2 Promotes De Novo Lipogenesis to Accelerate Hepatocyte Proliferation During Liver Regeneration.

Liver regeneration is a well-orchestrated compensatory process that is regulated by multiple factors. We recently reported the importance of the chromatin protein, a high-mobility group box 2 (HMGB2) in mouse liver regeneration. However, the molecular mechanism remains unclear. In this study, we aimed to study how HMGB2 regulates hepatocyte proliferation during liver regeneration. Seventy-percent partial hepatectomy (PHx) was performed in wild-type (WT) and HMGB2-knockout (KO) mice, and the liver tissues were used for microarray, immunohistochemistry, quantitative polymerase chain reaction (qPCR), and Western blotting analyses. In the WT mice, HMGB2-positive hepatocytes colocalized with cell proliferation markers. In the HMGB2-KO mice, hepatocyte proliferation was significantly decreased. Oil Red O staining revealed the transient accumulation of lipid droplets at 12-24 hr after PHx in the WT mouse livers. In contrast, decreased amount of lipid droplets were found in HMGB2-KO mouse livers, and it was preserved until 36 hr. The microarray, immunohistochemistry, and qPCR results demonstrated that the expression of lipid metabolism-related genes was significantly decreased in the HMGB2-KO mouse livers. The in vitro experiments demonstrated that a decrease in the amount of lipid droplets correlated with decreased cell proliferation activity in HMGB2-knockdown cells. HMGB2 promotes de novo lipogenesis to accelerate hepatocyte proliferation during liver regeneration.

Regeneration of Non-Alcoholic Fatty Liver Cells Using Chimeric FGF21/HGFR: A Novel Therapeutic Approach.

Non-alcoholic fatty liver disease (NAFLD) has emerged as a significant liver ailment attributed to factors like obesity and diabetes. While ongoing research explores treatments for NAFLD, further investigation is imperative to address this escalating health concern. NAFLD manifests as hepatic steatosis, precipitating insulin resistance and metabolic syndrome. This study aims to validate the regenerative potential of chimeric fibroblast growth factor 21 (FGF21) and Hepatocyte Growth Factor Receptor (HGFR) in NAFLD-afflicted liver cells. AML12, a murine hepatocyte cell line, was utilized to gauge the regenerative effects of chimeric FGF21/HGFR expression. Polysaccharide accumulation was affirmed through Periodic acid-Schiff (PAS) staining, while LDL uptake was microscopically observed with labeled LDL. The expression of FGF21/HGFR and NAFLD markers was analyzed by mRNA analysis with RT-PCR, which showed a decreased expression in acetyl-CoA carboxylase 1 (ACC1) and sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP) with increased expression of hepatocellular growth factor (HGF), hepatocellular nuclear factor 4 alpha (HNF4A), and albumin (ALB). These findings affirm the hepato-regenerative properties of chimeric FGF21/HGFR within AML12 cells, opening novel avenues for therapeutic exploration in NAFLD.

First-in-class MKK4 inhibitors enhance liver regeneration and prevent liver failure.

Diminished hepatocyte regeneration is a key feature of acute and chronic liver diseases and after extended liver resections, resulting in the inability to maintain or restore a sufficient functional liver mass. Therapies to restore hepatocyte regeneration are lacking, making liver transplantation the only curative option for end-stage liver disease. Here, we report on the structure-based development and characterization (nuclear magnetic resonance [NMR] spectroscopy) of first-in-class small molecule inhibitors of the dual-specificity kinase MKK4 (MKK4i). MKK4i increased liver regeneration upon hepatectomy in murine and porcine models, allowed for survival of pigs in a lethal 85% hepatectomy model, and showed antisteatotic and antifibrotic effects in liver disease mouse models. A first-in-human phase I trial (European Union Drug Regulating Authorities Clinical Trials [EudraCT] 2021-000193-28) with the clinical candidate HRX215 was conducted and revealed excellent safety and pharmacokinetics. Clinical trials to probe HRX215 for prevention/treatment of liver failure after extensive oncological liver resections or after transplantation of small grafts are warranted.

Natural antibodies are required for clearance of necrotic cells and recovery from acute liver injury.

Background & Aims: Hepatocellular necrosis is common in both acute and chronic liver injury and may evolve to fibrosis and liver failure. Injury leads to accumulation of necrotic cell debris in the liver, which drives persistent inflammation and poor recovery. This study investigated the role of natural antibodies (NAbs) in the clearance of necrotic cells in the injured liver, their impact on tissue regeneration and their potential as a therapy for acute liver injury. Methods: We used murine models of drug-induced liver injury and focal thermal injury in immunocompetent and antibody-deficient mice (Rag2-/- and IgMi). Intravital microscopy was used to investigate the role of NAbs in the phagocytosis of necrotic cells in the liver in vivo. Immunostainings were used to quantify the extent of liver necrosis (fibrin), antibody deposition (IgM and IgG) and cellular proliferation (Ki67). Results: Both IgM and IgG NAbs bound necrotic liver areas and opsonized multiple debris molecules released during hepatocellular necrosis such as DNA, histones, actin, phosphoinositides and mitochondrial cardiolipin, but not phosphatidylserine. Rag2-/- and IgMi mice presented impaired recovery from liver injury, which was correlated to the sustained presence of necrotic debris in the tissue, prolonged inflammation and reduced hepatocellular proliferation. These defects were rescued by treating mice with NAbs after the induction of injury. Mechanistically, in vitro and in vivo, phagocytosis of necrotic debris was dependent on NAbs via Fcγ receptors and CD11b. Moreover, NAb-mediated phagocytosis of necrotic cell debris occurs in two waves, firstly driven by neutrophils and then by recruited monocytes. Importantly, supplementation of immunocompetent mice with NAbs also improved liver regeneration significantly, demonstrating the therapeutic potential of natural IgM and IgG. Conclusion: NAbs drive the phagocytosis of necrotic cells in liver injury and promote liver regeneration and recovery. Impact and implications: Treatment with natural antibodies after acute liver injury improved recovery by increasing the clearance of necrotic debris and by improving cellular proliferation in the liver. This preclinical study provides a basis for the development of an immunotherapy for patients with early-stage, reversible, liver injury that aims to prevent disease chronification into fibrosis and liver failure.

Critical Roles of the Sphingolipid Metabolic Pathway in Liver Regeneration, Hepatocellular Carcinoma Progression and Therapy.

The sphingolipid metabolic pathway, an important signaling pathway, plays a crucial role in various physiological processes including cell proliferation, survival, apoptosis, and immune regulation. The liver has the unique ability to regenerate using bioactive lipid mediators involving multiple sphingolipids, including ceramide and sphingosine 1-phosphate (S1P). Dysregulation of the balance between sphingomyelin, ceramide, and S1P has been implicated in the regulation of liver regeneration and diseases, including liver fibrosis and hepatocellular carcinoma (HCC). Understanding and modulating this balance may have therapeutic implications for tumor proliferation, progression, and metastasis in HCC. For cancer therapy, several inhibitors and activators of sphingolipid signaling, including ABC294640, SKI-II, and FTY720, have been discussed. Here, we elucidate the critical roles of the sphingolipid pathway in the regulation of liver regeneration, fibrosis, and HCC. Regulation of sphingolipids and their corresponding enzymes may considerably influence new insights into therapies for various liver disorders and diseases.

Synergistic Hepatoprotective Effects of Mesenchymal Stem Cells and Platelet-Rich Plasma in a Rat Model of Bile Duct Ligation-Induced Liver Cirrhosis.

Liver cirrhosis poses a global health challenge marked by significant prevalence and mortality. Current therapeutic options are limited by high costs and immune-mediated rejection, necessitating the exploration of innovative strategies to enhance hepatic self-rehabilitation, and counteract the underlying pathological mechanisms. We evaluated the hepatoprotective activity of rat adipose-derived mesenchymal stem cells (ADMSCs) in combination with platelet-rich plasma (PRP) and recombinant human hepatocyte growth factor (rh-HGF) on a rat model of liver fibrosis/cirrhosis induced by bile duct ligation (BDL). Treatment with PRP or rh-HGF alone did not yield significant hepatoprotection in the BDL-induced liver cirrhosis model. However, ADMSC transplantation alone exhibited the potential to alleviate impaired liver conditions. The combination of PRP and rh-HGF demonstrated superior ameliorative effects compared to either treatment alone. Notably, the combination of ADMSC + PRP or ADMSC + rh-HGF significantly enhanced hepatoprotective capacity compared to individual or combined PRP and rh-HGF therapies. Injection of ADMSC via the tail vein reduced inflammation, hepatocyte damage, and collagen deposition, improving overall liver function. This improvement was more pronounced when ADMSC was administered with PRP and rh-HGF versus monotherapy. Our study concludes that ADMSCs exert antifibrotic effects by inhibiting hepatic stellate cell proliferation, collagen synthesis, and inducing apoptosis. ADMSCs also demonstrate immune-modulatory effects and transdifferentiate into hepatic progenitor cells, secreting trophic factors, cytokines, and chemokines that promote impaired liver regeneration. The observed arrest in liver fibrosis progression highlights the potential therapeutic impact of these interventions.

Single center experience with ALPPS and timing with stage 2 in patients with fibrotic/cirrhotic liver.

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a novel procedure for major resection in patients with insufficient future liver remnant (FLR). Effective FLR augmentation is pivotal in the completion of ALPPS. Liver fibrosis/cirrhosis associated with chronic viral hepatitis impairs liver regeneration. To investigate the augmentation of FLR in associating ALPPS between patients with fibrotic/cirrhotic livers (FL) and non-fibrotic livers (NFL) and compare their short-term clinical outcomes and long-term survival. Patients were divided into two groups based on the Ishak modified staging: non-fibrotic liver group (NFL, stage 0) and fibrotic/cirrhotic liver group (FL, stage 1-5/6). Weekly liver regeneration in FLR, perioperative data, and survival outcomes were investigated. Twenty-seven patients with liver tumors underwent ALPPS (NFL, n = 7; FL, n = 20). NFL and FL patients had viral hepatitis (28.6% [n = 2] and 95% [n = 19]), absolute FLR volume increments of 134.90 ml and 161.85 ml (p = 0.825), and rates of hypertrophy were 16.46 ml/day and 13.66 ml/day (p = 0.507), respectively. In the FL group, baseline FLR volume was 360.13 ml, postoperatively it increased to a plateau (542.30 ml) in week 2 and declined (378.45 ml) in week 3. One patient (3.7%) with cirrhotic liver (stage 6) failed to proceed to ALPPS-II. The overall ALPPS-related major complication rate was 7.4%. ALPPS is feasible for fibrotic liver patients classified by Ishak modified stages ≤ 5. After ALPPS-I, 14 days for FLR augmentation seems an appropriate waiting time to reach a maximum FLR volume in these patients.