Treatment Of Human Liver Diseases Research Articles

The antioxidant and anti-inflammatory activities of caffeine effectively attenuate nonalcoholic steatohepatitis and thioacetamide-induced hepatic injury in male rats

The antioxidant effect of caffeine, associated with its ability to upregulate the nuclear factor-E2-related factor-2 (Nrf2)-signaling pathway, was explored as a possible mechanism for the attenuation of liver damage. Nonalcoholic steatohepatitis (NASH) was induced in rats by the administration of a high-fat, high-sucrose, high-cholesterol diet (HFSCD) for 15 weeks. Liver damage was induced in rats by intraperitoneal administration of thioacetamide (TAA) for six weeks. Caffeine was administered orally at a daily dose of 50 mg/kg body weight during the period of NASH induction to evaluate its ability to prevent disease development. Meanwhile, rats received TAA for three weeks, after which 50 mg/kg caffeine was administered daily for three weeks with TAA to evaluate its capacity to interfere with the progression of hepatic injury. HFSCD administration induced hepatic steatosis, decreased Nrf2 levels, increased oxidative stress, induced the activation of nuclear factor-κB (NF-κB), and elevated proinflammatory cytokine levels, leading to hepatic damage. TAA administration produced similar effects, excluding steatosis. Caffeine increased Nrf2 levels; attenuated oxidative stress markers, including malondialdehyde and 4-hydroxynonenal; restored normal, reduced glutathione levels; and reduced NF-κB activation, inflammatory cytokine levels, and damage. Our findings suggest that caffeine may be useful in the treatment of human liver diseases.

Direct reprogramming of human umbilical vein- and peripheral blood-derived endothelial cells into hepatic progenitor cells

Recent advances have enabled the direct induction of human tissue-specific stem and progenitor cells from differentiated somatic cells. However, it is not known whether human hepatic progenitor cells (hHepPCs) can be generated from other cell types by direct lineage reprogramming with defined transcription factors. Here, we show that a set of three transcription factors, FOXA3, HNF1A, and HNF6, can induce human umbilical vein endothelial cells to directly acquire the properties of hHepPCs. These induced hHepPCs (hiHepPCs) propagate in long-term monolayer culture and differentiate into functional hepatocytes and cholangiocytes by forming cell aggregates and cystic epithelial spheroids, respectively, under three-dimensional culture conditions. After transplantation, hiHepPC-derived hepatocytes and cholangiocytes reconstitute damaged liver tissues and support hepatic function. The defined transcription factors also induce hiHepPCs from endothelial cells circulating in adult human peripheral blood. These expandable and bipotential hiHepPCs may be useful in the study and treatment of human liver diseases.

The Upstream Pathway of mTOR-Mediated Autophagy in Liver Diseases.

Autophagy, originally found in liver experiments, is a cellular process that degrades damaged organelle or protein aggregation. This process frees cells from various stress states is a cell survival mechanism under stress stimulation. It is now known that dysregulation of autophagy can cause many liver diseases. Therefore, how to properly regulate autophagy is the key to the treatment of liver injury. mechanistic target of rapamycin (mTOR)is the core hub regulating autophagy, which is subject to different upstream signaling pathways to regulate autophagy. This review summarizes three upstream pathways of mTOR: the phosphoinositide 3-kinase (PI3K)/protein kinase (AKT) signaling pathway, the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, and the rat sarcoma (Ras)/rapidly accelerated fibrosarcoma (Raf)/mitogen-extracellular activated protein kinase kinase (MEK)/ extracellular-signal-regulated kinase (ERK) signaling pathway, specifically explored their role in liver fibrosis, hepatitis B, non-alcoholic fatty liver, liver cancer, hepatic ischemia reperfusion and other liver diseases through the regulation of mTOR-mediated autophagy. Moreover, we also analyzed the crosstalk between these three pathways, aiming to find new targets for the treatment of human liver disease based on autophagy.

An experimental study on endoscopic ultrasound-guided microwave ablation for porcine liver and pancreas

Objective To evaluate the feasibility and safety of endoscopic ultrasound-guided microwave ablation (EUS-MWA) for porcine liver and pancreas by assessing physiological state and pathological changes. Methods EUS-MWA was performed on liver and pancreas of 8 healthy pigs after general anesthesia. The needle size was 1.9 mm in diameter, and the power of ablation was 65 W, 10 min on liver and 60 W, 5 min on pancreas. The levels of blood amylase and hepatic transaminase were examined before and after the operation. All pigs underwent CT scan on the right postoperative day to assess the extent of ablation and complications. Two pigs were killed 6 hours after operation and 2 others were killed 24 hours after operation to assess structural damage around the puncture path. The remaining 4 pigs were raised to 2 weeks after operation to observe diet, activities and mental state. The ablated areas of liver and pancreas underwent pathological analysis after dissection, and non-ablation regions were treated as the control. Results All 8 pigs underwent EUS-MWA and their vital signs were stable during the operation. Except for the difficulty in locating the pancreas in one case, other surgical procedures were smooth and 18 ablations were performed totally (10 in liver and 8 in pancreas). CT scans showed quasi-circular low density lesions in the liver and pancreas, and the maximum diameter of the ablation area in liver and pancreas was 2.8±0.3 cm, 1.8±0.2 cm respectively. There was no free intraperitoneal gas, ascites or pleural effusion. The level of blood amylase increased at 6 hours after operation and the peak value occurred within 12-24 hours. The level of hepatic transaminase had a mild elevation. The rearing group showed transient food refusal and activity reduction after the operation, but all returned to normal within 1-2 days. No fever, vomiting or other abnormalities occurred. Puncture path burn, adjacent organ damage and bleeding was not observed except for one case of gastric wall burns during pancreas ablation. Pathology showed massive coagulative necrosis and peripheral bleeding area in the liver ablation center, and diffuse focal necrosis in the tissue of the pancreatic ablation area. Conclusion EUS-MWA is safe and feasible for porcine liver and pancreas, which can be used for the treatment of human liver and pancreatic diseases in the future. Key words: Ultrasonography; Microwaves; Endoscopes; Animal experimentation

Pharmacokinetics in Vitro and in Vivo of Two Novel Prodrugs of Oleanolic Acid in Rats and Its Hepatoprotective Effects against Liver Injury Induced by CCl4.

Oleanolic acid (OA) is a well-known pentacyclic triterpenoid compound, which has been used as a dietary supplement and is supplied as an over-the-counter drug for the treatment of human liver diseases. These are reasons for the low bioavailability of OA which have restricted its wider application. In this study, two OA prodrugs (1,3-cyclic propanyl phosphate esters of OA) were designed and synthesized. The hepatoprotective effects of these prodrugs were evaluated against carbon tetrachloride (CCl4) induced liver injury in mice; the levels of alanine aminotransferase (ALT), lactic dehydrogenase (LDH), and aspartate aminotransferase (AST) were significantly increased, and the level of the hepatic malondialdehyde (MDA) was increased. The metabolism, in vitro, of the prodrugs was studied by incubation in rat liver microsome; the plasma pharmacokinetics and the biodistribution in vivo after intravenous (iv) injection to six rats were investigated, respectively. The prodrugs diminished gradually with time; most of the parent drugs were released within 30 min in vitro, and the presumed mechanism of the in vitro metabolism was confirmed. The plasma-concentration data in vivo was analyzed by a compartmental method: both the prodrugs and the corresponding released parent drugs existed at up to 48 h in rats. The t1/2 improved after intravenous administration in rats compared with direct injection of the parent drugs. All analyte concentrations were highest in the liver, and most of the prodrugs were excreted in feces (>47.11%). Therefore, 1,3-cyclic propanyl phosphate esters of OA can serve as a promising lead candidate for drugs.

Advances in Research on Hepatoprotective Activity and Synthesis of Oleanolic Acid Derivatives

Oleanolic acid (3b-hydroxyolean-12-en-28-oic acid) is a pentacyclic triterpenoid compound with a wide spread occurrence throughout the plant kingdom. During the last decade many research articles associated with oleanolic acid have been published. Particularly its hepatoprotective activity has been studied for many years. However, the clinical application of oleanolic acid has been limited by its poor solubility. In order to overcome this disadvantage, various approaches have been sought and many derivatives of oleanolic acid have been designed and synthesized. And some of these analogues show improved pharmacokinetic and pharmacodynamic properties, indicating that it may be promising candidates for the treatment of human liver diseases

Cytometry in stem cell research and therapy

recent Nobel Prize in medicine was awarded to two stemcell researchers, John Gurdon and Shinya Yamanaka, for theirachievements in stem cell research and reprogramming ofsomatic cells. Flow cytometry is by nature the ideal tool toidentify, characterize, and isolate stem and progenitor cells forresearch and potential clinical use (1). The major strength offlow cytometry is its ability to rapidly perform highlymultiplexed quantitative measurements on single cells withina heterogeneous cell population. However, when the cell typeof interest is extremely rare, as most stem and progenitor cellsare, several sources of artifact must be addressed. The impor-tance of flow cytometry as a driving force for stem cellresearch was demonstrated in a focused issue of the journalexactly three years ago (1). This current focus issue of Cytome-try A is devoted to the topic of stem cells due to numerouscurrent innovations and discoveries.Applications of stem cells include several disciplines,from embryogenesis, adult tissue maintenance, and repair,and more recently, cancer as well as for toxicity screening anddisease modeling. All of these topics are represented in thisissue, with special emphasis on the role of analytic and pre-parative flow cytometry in the elucidation of stem cell pheno-type and function, and best laboratory practices as they applyto flow cytometry. Image and flow cytometry together withcell sorting have revolutionized the study of stem cell biologyand the implications of these cells and their progeny indevelopmental biology, tissue engineering, and cellulartherapy. The number of parameters and the speed of theirsimultaneous measurements in single cells has continued toincrease with advances in hardware, reagents, and analyticalsoftware (2).

Effects of S/B Remedy Containing Scutellaria baicalensis and Bupleurum scorzonerifolfium on Hepatic Interleukin-6 Related Signal Transducer and Activator of Transcription 3 Activation in Mice through Cell-Cell Interaction

Signal transducer and activator of transcription 3 (STAT3) plays an important role in regulating interleukin 6 (IL-6) related growth control of the liver. Our previous study demonstrated that a mixture containing Scutellaria baicalensis and Bupleurum scorzonerifolfium (S/B remedy) modulated the growth of hepatocytes during liver regeneration after 2/3 partial hepatectomy. The aim of this study was to investigate whether S/B remedy induced mouse hepatic STAT3 activation directly in hepatocytes or indirectly via non-parenchymal cell-hepatocyte interaction. Direct S/B remedy effects were studied using primarily isolated hepatocytes; while C57BL/6J mice were used to study indirect effects of S/B remedy using gadolinium chloride to deplete Kupffer cells' function. The results showed that S/B remedy and its active constituents did not directly activate growth-related signaling in primarily isolated hepatocytes. However, S/B remedy induced STAT3 and subsequently suppressor of cytokine signaling (SOCS3) activation in mouse liver and increased serum IL-6 level in a dose-dependent manner, which could be partially blocked by pretreatment with gadolinium chloride. Oligonucloetide microarray analysis from S/B remedy-treated peripheral blood leukocytes demonstrated an up-regulation of IL-6 gene expression. We conclude that S/B remedy did not directly induce STAT3 activation in vitro, but induced hepatic IL-6 related STAT3 activation through non-parenchymal cell-hepatocyte interaction in vivo. The results provide important information on the molecular mechanisms of S/B remedy for treatment of human liver diseases.

Implications of the immunoregulatory functions of mesenchymal stem cells in the treatment of human liver diseases

Transplantation of mesenchymal stem cells (MSCs) has been recently studied in animal models, and in clinical trials of patients with fulminant hepatic failure, end-stage liver diseases and inherited metabolic disorders. Modulatory cytokines produced by MSCs can inhibit immunocyte proliferation and migration to the liver, thereby attenuating inflammatory injury and reducing hepatocyte apoptosis. In addition, MSCs play an important role in regressing liver fibrosis and in supporting the function, proliferation and differentiation of endogenous hepatocytes under appropriate conditions. Although remarkable progress has been achieved in basic and clinical MSC studies, optimal therapeutic regimens for the clinical application of MSCs, such as optimal doses, transplantation routine and interval period for transplantation, need to be elucidated in detail. Furthermore, the long-term safety and therapeutic efficacy of MSC transplantation should be evaluated in future clinical trials. This review summarizes our current understanding of the immunomodulatory effects of MSC therapies on human liver diseases.

III. JNK/AP-1 regulation of hepatocyte death

Activation of the JNK/activator protein-1 (AP-1)-signaling pathway is a common mediator of hepatocyte death from a variety of stimuli. Although the mechanism by which JNK or AP-1 promotes death is unknown, it results when activation of this signaling pathway is unusually prolonged. Although JNK/AP-1 mediates TNF-induced cell death at or above the level of the mitochondria, the ability of JNK/AP-1 to promote death from necrosis as well as apoptosis suggests that JNK/AP-1 may induce death by several mechanisms. Recognition of JNK/AP-1 signaling as a critical promoter of hepatocyte death raises the possibility that the therapeutic manipulation of this pathway may be effective in the treatment of human liver disease.

Liver stem cells: a potential source of hepatocytes for the treatment of human liver disease.

Severe liver injury often leads to the proliferation of oval cells, which differentiate along hepatocytic and biliary lineages. Because oval cells proliferate only when hepatocyte replication is impaired, they are considered to be the progeny of facultative liver stem cells (FLSCs). Identification and isolation of FLSCs has been hampered by the lack of markers that delineate these bipotential progenitors. We hypothesized that transition ductal cells are FLSCs because they are located in a unique anatomical niche sharing tight junctions with a neighboring hepatocyte and another terminal ductular cell. Alternatively, it has been proposed recently that bone marrow-derived stem cells are FLSCs since these cells differentiate along the hepatic lineage following colonization of the liver. The intent of this review is to provide insight into the nature and origin of liver stem cells and to explore the possibility that stem cell technology may lead to the development of clinical modalities for the treatment of human liver disease.

Reduction of liver Fas expression by an antisense oligonucleotide protects mice from fulminant hepatitis.

Aberrant apoptosis-mediated cell death is believed to result in a number of different human diseases. For example, excessive apoptosis in the liver can result in fulminant and autoimmune forms of hepatitis. We have explored the possibility that inhibition of Fas expression in mice would reduce the severity of fulminant hepatitis. To do this, we have developed a chemically modified 2'-O-(2-methoxy)ethyl antisense oligonucleotide (ISIS 22023) inhibitor of mouse Fas expression. In tissue culture, this oligonucleotide induced a reduction in Fas mRNA expression that was both concentration- and sequence-specific. In Balb/c mice, dosing with ISIS 22023 reduced Fas mRNA and protein expressions in liver by 90%. The ID50 for this response was 8-10 mg kg-1 daily dosing, and the reduction was highly dependent on oligonucleotide sequence, oligonucleotide concentration in liver, and treatment time. Pretreatment with ISIS 22023 completely protected mice from fulminant hepatitis induced by agonistic Fas antibody, by a mechanism entirely consistent with an oligonucleotide antisense mechanism of action. In addition, oligonucleotide-mediated suppression of Fas expression reduced the severity of acetaminophen-mediated fulminant hepatitis, but was without effect on concanavalin A-mediated hepatitis. Our results demonstrate that 2'-O-(2-methoxy)ethyl containing antisense oligonucleotides targeting Fas can exert in vivo pharmacological activity in liver, and suggest that oligonucleotide inhibitors of Fas may be useful in the treatment of human liver disease.

Prevention of carbon tetrachloride-induced rat liver injury by soluble tumor necrosis factor receptor

Background/Aims: Considerable indirect evidence suggests that cytokine tumor necrosis factor α contributes to the hepatocellular damage caused by toxic liver injury. The effects of tumor necrosis factor α neutralization on liver cell injury were determined in an in vivo model of toxic liver injury. Methods: The in vivo effects of tumor necrosis factor α were examined in carbon tetrachloride liver injury through the administration of a soluble tumor necrosis factor receptor to neutralize the effects of this cytokine. Results: Soluble tumor necrosis factor receptor treatment decreased the degree of liver injury as measured by reduced levels of serum liver enzymes and improved histology. Soluble tumor necrosis factor receptor administration also lowered the mortality from a lethal dose of carbon tetrachloride from 60% to 16%. Tumor necrosis factor α neutralization had no detrimental effect on liver regeneration as determined by the timing of histone gene expression and postinjury liver weight. Conclusions: These data provide direct evidence for a role of tumor necrosis factor α in toxin-induced liver cell injury. In addition, these investigations suggest that soluble tumor necrosis factor receptor therapy may be of benefit in the treatment of human liver disease.

16,16-dimethyl prostaglandin E2 delays collagen formation in nutritional injury in rat liver

Chronic nutritional injury was induced in rats by a high-fat, lipotrope-deficient diet. The hepatoprotective effect of 16,16-dimethyl prostaglandin E2 on the deposition of collagen and fat was assessed by histological evaluation and measurement of hydroxyproline. Dose-response studies established that optimal protection was achieved by the twice daily administration of 16,16-dimethyl prostaglandin E2 at 100 micrograms per kg (subcutaneous) or 250 micrograms per kg (oral). 16,16-Dimethyl prostaglandin E2 and a crystalline analog [(p-acetamidobenzamido)phenyl ester of 16,16-dimethyl prostaglandin E2 significantly delayed both the deposition of collagen and the increase in hepatic hydroxyproline content. There was an excellent correlation between the histological assessment of collagen and the biochemical measurement of hydroxyproline. These data provide a rationale for the evaluation of prostaglandins in the treatment of human liver disease.

Homotransplantation of the liver.

The feasibility of hepatic homotransplantation has been clearly established in principle inasmuch as several animals are still alive almost 3 years after complete hepatectomy and liver replacement. Both orthotopic and auxiliary operations are complicated surgical techniques. Nevertheless, the results in dogs are comparable to those which can be obtained with homotransplantation of the kidney. In man the problem is more difficult. In patients who have a need for such operations, there is invariably a metabolic disorder more complex than that caused by renal failure. In addition, the new organ must function efficiently from the beginning since its complete functional failure leads to death within a few hours. There is no recourse to an artificial liver to maintain life until the reversal of an injury which is caused by either ischemia or rejection. Nevertheless, research of several kinds may soon make possible the successful use of hepatic transplantation procedures for the definitive treatment of human liver disease as exemplified by the reports in this symposium concerning new techniques of organ preservation, histocompatibility analysis, and immunosuppression. © 1967 by The Williams and Wilkins Co.