Pyridostigmine attenuated high-fat-diet induced liver injury by the reduction of mitochondrial damage and oxidative stress via α7nAChR and M3AChR.

Obesity is a major cause of nonalcohol fatty liver disease (NAFLD), which is characterized by hepatic fibrosis, lipotoxicity, inflammation, and apoptosis. Previous studies have shown that an imbalance in the autonomic nervous system is closely related to the pathogenesis of NAFLD. In this study, we investigated the effects of pyridostigmine (PYR), a cholinesterase (AChE) inhibitor, on HFD-induced liver injury and explored the potential mechanisms involving mitochondrial damage and oxidative stress. A murine model of HFD-induced obesity was established using the C57BL/6 mice, and PYR (3 mg/kg/d) or placebo was administered for 20 weeks. PYR reduced the body weight and liver weight of the HFD-fed mice. Additionally, the serum levels of IL-6, TNF-α, cholesterol, and triglyceride were significantly lower in the PYR-treated versus the untreated mice, corresponding to a decrease in hepatic fibrosis, lipid accumulation, and apoptosis in the former. Furthermore, the mitochondrial morphology improved significantly in the PYR-treated group. Consistently, PYR upregulated ATP production and the mRNA level of the mitochondrial dynamic factors OPA1, Drp1 and Fis1, and the mitochondrial unfolded protein response (UPRmt) factors LONP1 and HSP60. Moreover, PYR treatment activated the Keap1/Nrf2 pathway and upregulated HO-1 and NQO-1, which mitigated oxidative injury as indicated by decreased 8-OHDG, MDA and H2 O2 levels, and increased SOD activity. Finally, PYR elevated acetylcholine (ACh) levels by inhibiting AChE, and upregulated the α7nAChR and M3AChR proteins in the HFD-fed mice. PYR alleviated obesity-induced hepatic injury in mice by mitigating mitochondrial damage and oxidative stress via α7nAChR and M3AChR.

COVID-19 vaccine-induced liver injury.

PURPOSE OF REVIEW: The rapid rollout and uptake of novel coronavirus disease 2019 (COVID-19) vaccines has been accompanied by a small yet noticeable accumulation of reports of liver injury occurring after vaccination. This review describes the present evidence surrounding COVID-19 vaccine-induced liver injury (VILI). RECENT FINDINGS: Liver injury occurring after the COVID-19 vaccine often presents clinically similar to autoimmune hepatitis, with positive autoantibodies and a portal and lobular inflammatory infiltrate and varying degrees of necrosis on biopsy. The overwhelming majority of patients recover, often spontaneously or with a limited course of immunosuppression. The overall incidence of this phenomenon appears to be exceedingly low. SUMMARY: Providers should remain vigilant for ongoing reports of VILI after COVID-19 and yet feel reassured by the low incidence and high likelihood of recovery. Ongoing genetic and histological study, as well as longer-term follow-up of presently identified cases, will shed further light on the clinical entity of VILI.

Vancomycin-Induced Liver Injury, DRESS, and HLA-A∗32:01.

BACKGROUND: Intravenous vancomycin therapy can cause liver injury as well as "drug reaction with eosinophilia and systemic symptoms" (DRESS) syndrome. This study aimed to better define the clinical features and HLA associations of vancomycin-induced liver injury. OBJECTIVE: To describe clinical, biochemical, and temporal characteristics of vancomycin-induced liver injury. METHODS: Cases of liver injury with recent exposure to vancomycin who were enrolled in the US Drug-induced Liver Injury Network between 2004 and 2020 were assessed. Sequencing of HLA alleles was performed on stored blood samples. RESULTS: Among 1697 cases of drug-induced liver injury identified between 2004 and 2021, 9 (0.5%) were attributed to intravenous vancomycin. The 9 cases included 6 men, median age 60 years (range, 23-85 days), and treatment for 26 days (range, 1-34 days). The clinical presentation was DRESS syndrome in 8 patients, of whom 6 received corticosteroids. Liver injury varied from hepatocellular to cholestatic and from mild (n = 5) to fatal (n = 1). In survivors, liver injury and DRESS syndrome ultimately resolved. HLA typing demonstrated the HLA-A∗32:01 allele in 7 vancomycin cases (78%, all with DRESS syndrome), versus 1 of 81 cases (1.2%) exposed but not attributed to vancomycin, and 113 of 1708 cases (6.6%) without vancomycin exposure. The allele frequency in vancomycin cases was 0.44 compared with less than 0.04 in US populations. CONCLUSIONS: Vancomycin-induced liver injury is commonly associated with DRESS syndrome and linked to HLA-A∗32:01. HLA-A∗32:01 testing could be considered early to risk-stratify patients using long-term intravenous vancomycin therapy.

Prospective Assessment of Treatment-Induced Liver Injury as a Cause of Diffuse Pathologic Hepatic Enhancement in Contrast-Enhanced Ultrasound.

OBJECTIVE: A hypo-enhancement of the liver in contrast-enhanced ultrasound (CEUS), pathologic one-minute hepatic enhancement (pOMHE), was recently observed in 70% of allogeneic hematopoietic stem cell transplantation patients with a high-risk profile for veno-occlusive disease (VOD). Whether pOMHE was a pre-clinical sign of VOD or an unspecific feature of liver damage secondary to intensive chemotherapy is unclear. METHODS: To investigate this, we studied CEUS patterns in patients receiving high-dose chemotherapy prior to autologous hematopoietic stem cell transplantation (auto-HSCT) or intensive induction therapy (IT) for the treatment of acute leukemia. From April 2020 to May 2021, patients undergoing auto-HSCT (n = 20) or acute leukemia patients prior to IT (n = 20) were included. All patients underwent a B-mode ultrasound and CEUS of the liver and spleen before treatment (d0) and on day 10 (d10) after therapy start. The one-minute hepatic enhancement was quantified. An optical density of liver enhancement less than 90% compared with the spleen was considered pathologic (pOMHE). Clinical and laboratory parameters used to assess a drug-induced liver injury (DILI) were documented. RESULTS: The OMHE was normal (d0 and d10) in 36 (90%) patients. After IT, 2 of 20 patients had a pOMHE. A DILI grade IV was diagnosed in one case and hyperfibrinolysis in the second case. In 2 of 20 (5%) auto-HSCT patients a pOMHE was observed at d10 without clinical symptoms. CONCLUSION: Chemotherapy-induced effects are not the cause of a pathologic liver enhancement. In contrast, severe DILI or hyperfibrinolysis can be associated with pOMHE.

SARS-CoV-2 induced liver injury: Incidence, risk factors, impact on COVID-19 severity and prognosis in different population groups.

Liver is unlikely the key organ driving mortality in coronavirus disease 2019 (COVID-19) however, liver function tests (LFTs) abnormalities are widely observed mostly in moderate and severe cases. According to this review, the overall prevalence of abnormal LFTs in COVID-19 patients ranges from 2.5% to 96.8% worldwide. The geographical variability in the prevalence of underlying diseases is the determinant for the observed discrepancies between East and West. Multifactorial mechanisms are implicated in COVID-19-induced liver injury. Among them, hypercytokinemia with "bystander hepatitis", cytokine storm syndrome with subsequent oxidative stress and endotheliopathy, hypercoagulable state and immuno-thromboinflammation are the most determinant mechanisms leading to tissue injury. Liver hypoxia may also contribute under specific conditions, while direct hepatocyte injury is an emerging mechanism. Except for initially observed severe acute respiratory distress syndrome corona virus-2 (SARS-CoV-2) tropism for cholangiocytes, more recent cumulative data show SARS-CoV-2 virions within hepatocytes and sinusoidal endothelial cells using electron microscopy (EM). The best evidence for hepatocellular invasion by the virus is the identification of replicating SARS-CoV-2 RNA, S protein RNA and viral nucleocapsid protein within hepatocytes using in-situ hybridization and immunostaining with observed intrahepatic presence of SARS-CoV-2 by EM and by in-situ hybridization. New data mostly derived from imaging findings indicate possible long-term sequelae for the liver months after recovery, suggesting a post-COVID-19 persistent live injury.

Evaluation and subgroup analysis of the efficacy and safety of intensive rosuvastatin therapy combined with dual antiplatelet therapy in patients with acute ischemic stroke.

OBJECTIVES: We investigated the efficacy of intensive rosuvastatin therapy plus 7-day dual antiplatelet therapy (DAPT) in reducing stroke recurrence for patients with acute ischemic stroke (AIS) and compared subgroups of patients. METHODS: We enrolled patients with AIS whose time of onset to medication was ≤ 72 h, and the baseline scores of NIHSS (bNIHSS) were 0-10. The patients received intensive rosuvastatin therapy plus 7-day DAPT with aspirin and clopidogrel (study group) or rosuvastatin plus single antiplatelet therapy (SAPT, control group). The primary outcomes were recurrence of ischemic stroke, bleeding, statin-induced liver injury, and statin-associated myopathy (SAM) within 90 days. We also performed a subgroup analysis to assess the heterogeneity of the two therapy regimens in reducing recurrent stroke. RESULTS: Recurrent stroke occurred in 10 patients in the study group and 42 patients in the control group (hazard ratio [HR], 0.373, 95% confidence interval [CI], 0.178-0.780; P = 0.009). Bleeding events occurred in 9 patients in the study group and 14 patients in the control group (HR, 1.019; 95%CI, 0.441-2.353; P = 0.966). Statin-induced liver injury and SAM were not recorded. Intensive rosuvastatin plus 7-day DAPT was generally effective in reducing the risk of recurrent stroke, except in the subgroup with bNIHSS ≤ 2. The therapy was particularly efficient in the elderly, male, high-bNIHSS, and hypertension, diabetes, and hyperlipidemia subgroups, with P < 0.02. CONCLUSIONS: Without increasing bleeding and statin-associated adverse events, intensive rosuvastatin therapy plus 7-day DAPT significantly reduced the risk of recurrent stroke, especially for subgroups with high-risk factors. CLINICAL TRIAL REGISTRATION: China Clinical Trial Registration Center (ChiCTR1800017809).

Compound Probiotic Ameliorates Acute Alcoholic Liver Disease in Mice by Modulating Gut Microbiota and Maintaining Intestinal Barrier.

Alcoholic liver disease (ALD) is a worldwide health threaten lack of effective treatment. Gut dysbiosis and concomitant augmented intestinal permeability are strongly implicated in the pathogenesis and progression of ALD. Research on the protective effect of probiotics on ALD is limited, and more effective intestinal microecological regulators and the related mechanisms still need to be further explored. In the present study, the protective effects and mechanisms of a compound probiotic against acute alcohol-induced liver injury in vivo were explod. It was showed that the compound probiotic ameliorated liver injury in acute ALD mice and stabilized the levels of ALT, AST, and TG in serum. The compound probiotic reversed acute alcohol-induced gut dysbiosis and maintained the intestinal barrier integrity by upregulating the production of mucus and the expression of tight junction (TJ) proteins and thus reduced LPS level in liver. Meanwhile, the compound probiotic reduced inflammation level by inhibiting TLR4/NF-κB signaling pathway and suppressed oxidative stress level in liver. Furthermore, the compound probiotic alleviated liver lipid accumulation by regulating fatty acid metabolism-associated genes and AMPK-PPARα signaling pathway. Noteworthy, fecal microbiota transplantation (FMT) realized comparable protective effect with that of compound probiotic. In conclusion, present study demonstrates the beneficial effects and underlying mechanism of the compound probiotic against acute alcohol-induced liver injury. It provides clues for development of novel strategy for treatment of ALD.

Targeting VEGF using Bevacizumab attenuates sepsis-induced liver injury in a mouse model of cecal ligation and puncture.

Sepsis, a life-threatening condition resulting from an uncontrolled host response to infection, often leads to severe liver damage and remains a significant cause of mortality in critically ill patients despite advances in antibiotic therapy and resuscitation. Bevacizumab, a neutralizing antibody targeting vascular endothelial growth factor (VEGF), is approved for treating certain cancers. However, its potential impact on sepsis-related liver injury is not well understood. This study aimed to explore the potential hepatoprotective effect of Bevacizumab on sepsis-induced liver injury. Twenty-four mice were divided into four groups: a sham group subjected to a midline incision only, a cecal ligation and puncture induction (CLP) group, a vehicle-treated group that received a vehicle one hour before CLP induction, and a Bevacizumab-treated group that received Bevacizumab one hour before CLP induction. Blood samples were collected, and angiopoietin-2 (ANGPT2), alanine transaminase (ALT), and aspartate transaminase (AST) serum levels were measured. Liver tissue homogenates were analyzed for IL-6, TNFα, intracellular adhesion molecule (ICAM-1), macrophage inhibitory factor (MIF), vascular endothelial growth factor (VEGF), F2-isoprostane, and caspase-11 levels. A histological examination was performed to assess the extent of liver damage. Mice exposed to CLP had high levels of the biomarkers mentioned above with a high degree of liver injury compared to the sham group. In contrast, treatment with Bevacizumab notably reduced these markers and mitigated liver damage. In conclusion, Bevacizumab may be a protective agent against sepsis-induced liver injury.

The pathogenesis and therapeutic strategies of heat stroke-induced liver injury.

Heat stroke (HS) is a life-threatening systemic disease characterized by an elevated core body temperature of more than 40 â„ƒ and subsequent multiple organ dysfunction syndrome. With the growing frequency of global heatwaves, the incidence rate of HS has increased significantly, which has caused a huge burden on people's lives and health. Liver injury is a well-documented complication of HS and usually constitutes the direct cause of patient death. In recent years, a lot of research has been carried out on the pathogenesis and treatment strategies of HS-induced liver injury. In this review, we summarized the important pathogenesis of HS-induced liver injury that has been confirmed so far. In addition to the comprehensive effect of systemic factors such as heat cytotoxicity, coagulopathy, and systemic inflammatory response syndrome, excessive hepatocyte cell pyroptosis, dysfunction of Kupffer cells, abnormal expression of heat shock protein expression, and other factors are also involved in the pathogenesis of HS-induced liver injury. Furthermore, we have also established the current therapeutic strategies for HS-induced liver injury. Our study is of great significance in promoting the understanding of the pathogenesis and treatment of HS-induced liver injury.

Intestinal Osteopontin Protects From Alcohol-induced Liver Injury by Preserving the Gut Microbiome and the Intestinal Barrier Function.

BACKGROUND & AIMS: The gut-liver axis plays a key role in the pathogenesis of alcohol-associated liver disease (ALD). We demonstrated that Opn-/- develop worse ALD than wild-type (WT) mice; however, the role of intestinal osteopontin (OPN) in ALD remains unknown. We hypothesized that overexpression of OPN in intestinal epithelial cells (IECs) could ameliorate ALD by preserving the gut microbiome and the intestinal barrier function. METHODS: OpnKI IEC, OpnΔIEC, and WT mice were fed control or ethanol Lieber-DeCarli diet for 6 weeks. RESULTS: OpnKI IEC but not OpnΔIEC mice showed improved intestinal barrier function and protection from ALD. There were less pathogenic and more beneficial bacteria in ethanol-fed OpnKI IEC than in WT mice. Fecal microbiome transplant (FMT) from OpnKI IEC to WT mice protected from ALD. FMT from ethanol-fed WT to OpnKI IEC mice failed to induce ALD. Antimicrobial peptides, Il33, pSTAT3, aryl hydrocarbon receptor (Ahr), and tight-junction protein expression were higher in IECs from jejunum of ethanol-fed OpnKI IEC than of WT mice. Ethanol-fed OpnKI IEC showed more tryptophan metabolites and short-chain fatty acids in portal serum than WT mice. FMT from OpnKI IEC to WT mice enhanced IECs Ahr and tight-junction protein expression. Oral administration of milk OPN replicated the protective effect of OpnKI IEC mice in ALD. CONCLUSION: Overexpression of OPN in IECs or administration of milk OPN maintain the intestinal microbiome by intestinal antimicrobial peptides. The increase in tryptophan metabolites and short-chain fatty acids signaling through the Ahr in IECs, preserve the intestinal barrier function and protect from ALD.

Propionate Ameliorates Alcohol-Induced Liver Injury in Mice via the Gut-Liver Axis: Focus on the Improvement of Intestinal Permeability.

Alcohol-related liver disease (ALD) is a major cause of chronic liver disease worldwide with limited therapeutic options. Here, we first revealed the promising beneficial effect of gut microbiota-derived propionate on alcoholic liver injury in mice. This effect was dependent on the modulation of homeostasis of the gut-liver axis, especially the improvement of intestinal permeability. Dietary supplementation with propionate protected against ethanol-induced loss of hepatic function and hepatic steatosis in mice. Meanwhile, propionate treatment attenuated intestinal epithelial barrier dysfunction, restored the expression of intestinal mucus layer components, suppressed intestinal inflammation, and altered intestinal microbiota dysbiosis, which inhibited the intestinal hyperpermeability and subsequently reduced lipopolysaccharide leakage in ALD mice. Furthermore, as a consequence of endotoxemia amelioration, the liver inflammation-related TLR4-NF-κB pathway was inhibited. Collectively, our results suggested that propionate supplementation may be a promising option for the prevention and treatment of ALD.

Corticosteroid-Induced Liver Injury in Adult-Onset Still's Disease.

Background and Objectives: Adult-onset Still's disease (AOSD) is a rheumatic disease characterized by systemic inflammatory symptoms, including intermittent spiking fever, polyarthritis and a distinctive salmon-colored rash. Corticosteroids are the first-line treatment for AOSD. However, corticosteroids are potentially hepatotoxic in certain cases and may complicate the course of the disease. Materials and Methods: A 29-year-old female suffering from fever of unknown origin for two weeks was diagnosed with AOSD according to Yamaguchi's criteria. She received corticosteroids as the first-line treatment for AOSD and developed acute severe hepatitis. A diagnostic protocol has been performed. Results: Corticosteroid-induced liver injury was confirmed by clinical observation and rechallenge of the drug in this case. The result of liver biopsy also supported the diagnosis. Mycophenolic acid, a disease-modifying antirheumatic drug (DMARD) was chosen as an alternative treatment. AOSD remission was achieved under this treatment after three months. Conclusions: Severe acute hepatitis induced by corticosteroids, although very rare, may be observed in patients with AOSD. Drug-induced liver injury needs to be kept in mind when unexpected acute hepatitis is found. Mycophenolic acid could be a proper substitute medication in these cases.

Spontaneous extradural hematoma: a rare entity.

Spontaneous onset extradural hematoma (EDH) is a very rare entity and has been seen mostly to be associated with adjacent infective pathologies, dural vascular malformations, extradural metastasis, or coagulopathies. We report a series of two such cases and review the literature. One case presented with spontaneous EDH that was managed conservatively and was diagnosed to have chronic kidney disease later; the other had deranged coagulation profile and liver function secondary to drug induced hepatitis and was operated. Both patients were discharged in a stable condition and were improving on follow up.

Acute liver failure.

Acute liver failure is a rare and severe consequence of abrupt hepatocyte injury, and can evolve over days or weeks to a lethal outcome. A variety of insults to liver cells result in a consistent pattern of rapid-onset elevation of aminotransferases, altered mentation, and disturbed coagulation. The absence of existing liver disease distinguishes acute liver failure from decompensated cirrhosis or acute-on-chronic liver failure. Causes of acute liver failure include paracetamol toxicity, hepatic ischaemia, viral and autoimmune hepatitis, and drug-induced liver injury from prescription drugs, and herbal and dietary supplements. Diagnosis requires careful review of medications taken, and serological testing for possible viral exposure. Because of its rarity, acute liver failure has not been studied in large, randomised trials, and most treatment recommendations represent expert opinion. Improvements in management have resulted in lower mortality, although liver transplantation, used in nearly 30% of patients with acute liver failure, still provides a life-saving alternative to medical management.

Assessment of Serious Acute and Chronic Idiosyncratic Drug-Induced Liver Injury in Clinical Practice.

Drug-induced liver injury (DILI) is the leading cause of acute liver failure (ALF) in developed countries. The extremely variable phenotype of DILI, both in presentation and in severity, is one of the distinctive characteristics of the disease and one of the major challenges that hepatologists face when assessing hepatotoxicity cases. A new Hy's law that more accurately predicts the risk of ALF related to DILI has been proposed and validated. Other prognostic scoring algorithms for the early identification of DILI patients who may go on to develop ALF have been developed as it is of most clinical relevance to stratify patients for closer monitoring. Recent data indicate that acute DILI often presents a more prolonged resolution or evolves into chronicity at a higher frequency than other forms of acute liver injury. Risk factors for chronicity, specific phenotypes, and histological features are discussed in this study. Biomarkers to predict DILI outcome are in need.

Chronic liver injury alters driver mutation profiles in hepatocellular carcinoma in mice.

Most hepatocellular carcinomas (HCCs) develop in a chronically injured liver, yet the extent to which this microenvironment promotes neoplastic transformation or influences selective pressures for genetic drivers of HCC remains unclear. We sought to determine the impact of hepatic injury in an established mouse model of HCC induced by Sleeping Beauty transposon mutagenesis. Chemically induced chronic liver injury dramatically increased tumor penetrance and significantly altered driver mutation profiles, likely reflecting distinct selective pressures. In addition to established human HCC genes and pathways, we identified several injury-associated candidates that represent promising loci for further study. Among them, we found that FIGN is overexpressed in human HCC and promotes hepatocyte invasion. We also validated Gli2's oncogenic potential in vivo, providing direct evidence that Hedgehog signaling can drive liver tumorigenesis in the context of chronic injury. Finally, we show that a subset of injury-associated candidate genes identifies two distinct classes of human HCCs. Further analysis of these two subclasses revealed significant trends among common molecular classification schemes of HCC. The genes and mechanisms identified here provide functional insights into the origin of HCC in a chronic liver damage environment. CONCLUSION: A chronically damaged liver microenvironment influences the genetic mechanisms that drive hepatocarcinogenesis. (Hepatology 2018;67:924-939).

Risk of liver decompensation with cumulative use of mitochondrial toxic nucleoside analogues in HIV/hepatitis C virus coinfection.

PURPOSE: Among patients dually infected with human immunodeficiency virus (HIV) and chronic hepatitis C virus (HCV), use of antiretroviral therapy (ART) containing mitochondrial toxic nucleoside reverse transcriptase inhibitors (mtNRTIs) might induce chronic hepatic injury, which could accelerate HCV-associated liver fibrosis and increase the risk of hepatic decompensation and death. METHODS: We conducted a cohort study among 1747 HIV/HCV patients initiating NRTI-containing ART within the Veterans Aging Cohort Study (2002-2009) to determine if cumulative mtNRTI use increased the risk of hepatic decompensation and death among HIV-/HCV-coinfected patients. Separate marginal structural models were used to estimate hazard ratios (HRs) of each outcome associated with cumulative exposure to ART regimens that contain mtNRTIs versus regimens that contain other NRTIs. RESULTS: Over 7033 person-years, we observed 97 (5.6%) decompensation events (incidence rate, 13.8/1000 person-years) and 125 (7.2%) deaths (incidence rate, 17.8 events/1000 person-years). The risk of hepatic decompensation increased with cumulative mtNRTI use (1-11 mo: HR, 1.79 [95% confidence interval (CI), 0.74-4.31]; 12-35 mo: HR, 1.39 [95% CI, 0.68-2.87]; 36-71 mo: HR, 2.27 [95% CI, 0.92-5.60]; >71 mo: HR, 4.66 [95% CI, 1.04-20.83]; P = .045) versus nonuse. Cumulative mtNRTI use also increased risk of death (1-11 mo: HR, 2.24 [95% CI, 1.04-4.81]; 12-35 mo: HR, 2.05 [95% CI, 0.68-6.20]; 36-71 mo: HR, 3.04 [95% CI, 1.12-8.26]; >71 mo: HR, 3.93 [95% CI, 0.75-20.50]; P = .030). CONCLUSIONS: These findings suggest that cumulative mtNRTI use may increase the risk of hepatic decompensation and death in HIV/HCV coinfection. These drugs should be avoided when alternatives exist for HIV/HCV patients.

Sphingosine-1-Phosphate Prevents Egress of Hematopoietic Stem Cells From Liver to Reduce Fibrosis.

BACKGROUND & AIMS: There is growing interest in the use of bone marrow cells to treat liver fibrosis, however, little is known about their antifibrotic efficacy or the identity of their effector cell(s). Sphingosine-1-phosphate (S1P) mediates egress of immune cells from the lymphoid organs into the lymphatic vessels; we investigated its role in the response of hematopoietic stem cells (HSCs) to liver fibrosis in mice. METHODS: Purified (c-kit+/sca1+/lin-) HSCs were infused repeatedly into mice undergoing fibrotic liver injury. Chronic liver injury was induced in BoyJ mice by injection of carbon tetrachloride (CCl4) or placement on a methionine-choline-deficient diet. Some mice were irradiated and given transplants of bone marrow cells from C57BL6 mice, with or without the S1P antagonist FTY720; we then studied HSC mobilization and localization. Migration of HSC lines was quantified in Transwell assays. Levels of S1P in liver, bone marrow, and lymph fluid were measured using an enzyme-linked immunosorbent assay. Liver tissues were collected and analyzed by immunohistochemical quantitative polymerase chain reaction and sphingosine kinase activity assays. We performed quantitative polymerase chain reaction analyses of the expression of sphingosine kinase 1 and 2, sphingosine-1-phosphate lyase 1, and sphingosine-1-phosphate phosphatase 1 in normal human liver and cirrhotic liver from patients with alcohol-related liver disease (n = 6). RESULTS: Infusions of HSCs into mice with liver injury reduced liver scarring based on picrosirius red staining (49.7% reduction in mice given HSCs vs control mice; P < .001), and hepatic hydroxyproline content (328 mg/g in mice given HSCs vs 428 mg/g in control mice; P < .01). HSC infusion also reduced hepatic expression of α-smooth muscle actin (0.19 ± 0.007-fold compared with controls; P < .0001) and collagen type I α 1 chain (0.29 ± 0.17-fold compared with controls; P < .0001). These antifibrotic effects were maintained with infusion of lymphoid progenitors that lack myeloid potential and were associated with increased numbers of recipient neutrophils and macrophages in liver. In studies of HSC cell lines, we found HSCs to recruit monocytes, and this process to require C-C motif chemokine receptor 2. In fibrotic liver tissue from mice and patients, hepatic S1P levels increased owing to increased hepatic sphingosine kinase-1 expression, which contributed to a reduced liver:lymph S1P gradient and limited HSC egress from the liver. Mice given the S1P antagonist (FTY720) with HSCs had increased hepatic retention of HSCs (1697 ± 247 cells in mice given FTY720 vs 982 ± 110 cells in controls; P < .05), and further reductions in fibrosis. CONCLUSIONS: In studies of mice with chronic liver injury, we showed the antifibrotic effects of repeated infusions of purified HSCs. We found that HSCs promote recruitment of endogenous macrophages and neutrophils. Strategies to reduce SIP signaling and increase retention of HSCs in the liver could increase their antifibrotic activities and be developed for treatment of patients with liver fibrosis.

Prevention of liver fibrosis by intrasplenic injection of high-density cultured bone marrow cells in a rat chronic liver injury model.

Endothelial progenitor cells (EPCs) from bone marrow have proven to be functional for the prevention of liver fibrosis in chronic liver injury. However, expansion of EPCs in culture is complicated and expansive. Previously, we have established a simple method that could enrich and expand EPCs by simple seeding bone marrow cells in high density dots. The purpose of this study is to evaluate whether cells derived from high-density (HD) culture of rat bone marrow cells could prevent the liver fibrosis in a chronic liver injury rat model, induced by carbon tetrachloride (CCl4). Flow cytometric analysis showed that cells from HD culture were enriched for EPCs, expressing high levels of EPC markers. Intrasplenic injection of HD cultured bone marrow cells in the CCl4-induced liver injury rat showed an enhanced antifibrogenic effect compared with animals treated with cells from regular-density culture. The antifibrogenic effect was demonstrated by biochemical and histological analysis 4 weeks post-transplantation. Furthermore, cells from HD culture likely worked through increasing neovascularization, stimulating liver cell proliferation, and suppressing pro-fibrogenic factor expression. HD culture, which is a simple and cost-effective procedure, could potentially be used to expand bone marrow cells for the treatment of liver fibrosis.