Growth-stimulating factor in regenerating canine liver

Augmenter of liver regeneration (ALR) regulates acute pancreatitis via inhibiting HMGB1/TLR4/NF-κB signaling pathway

This research aimed to explore the effect of augmenter of liver regeneration (ALR) in acute pancreatitis (AP) of mice and the underlying mechanism. Caerulein were given to mice to get AP models. AP mice were given saline, ALR plasmids or negative control plasmids. Then, pancreas tissues were fixed and stained for histological examination. The levels of serum amylase, serum lipase, MPO, HMGB1, TNF-α, IL-1β as well as MCP-1 were detected by ELISA assay. The mRNA levels of TLR4, p65, IκBα, iNOS, COX-2 and GAPDH were examined by RT-qPCR. The protein levels of HMGB1, TLR4, MD2, MyD88, IκBα and GAPDH were detected by western blotting. ALR decreased serum amylase as well as lipase levels and alleviated the histopathological alterations of the pancreas in AP mice. ALR decreased the MPO activity of pancreas in AP Mice. ALR decreased the HMGB1/TLR4 signaling pathway in AP Mice. ALR decreased pancreas IL-1β and MCP-1 in AP mice, and also decreased plasma TNF-α and IL-1β in AP mice. ALR attenuated the cerulein-caused increase in p65 mRNA and protein levels, but had no effects on mRNA and protein levels of IκBα. The AP mice significantly promoted the mRNA levels of iNOS and COX-2 that was inhibited by ALR. HNE formation was also increased in AP mice, but it was decreased by ALR. ALR alleviates acute pancreatitis by inhibiting HMGB1/TLR4/NF-κB signaling pathway. It is promising to alleviate the syndromes of patients with acute via targeting ALR.

ALR, the multifunctional protein

ALR is a mystic protein. It has a so called “long” 22 kDa and a “short” 15 kDa forms. It has been described after partial hepatectomy and it has just been considered as a key protein of liver regeneration. At the beginning of the 21st century it has been revealed that the “long” form is localized in the mitochondrial intermembrane space and it is an element of the mitochondrial protein import and disulphide relay system. Several proteins of the substrates of the mitochondrial disulphide relay system are necessary for the proper function of the mitochondria, thus any mutation of the ALR gene leads to mitochondrial diseases. The “short” form of ALR functions as a secreted extracellular growth factor and it promotes the protection, regeneration and proliferation of hepatocytes. The results gained on the recently generated conditional ALR mutant mice suggest that ALR can play an important role in the pathogenesis of alcoholic and non-alcoholic steatosis. Since the serum level of ALR is modified in several liver diseases it can be a promising marker molecule in laboratory diagnostics. Orv. Hetil., 2015, 156(13), 503–509.

Human fetal liver stromal cell co-culture enhances the differentiation of pancreatic progenitor cells into islet-like cell clusters

Recent advance in directed differentiation of pancreatic stem cells offers potential to the development of replacement therapy for diabetic patients. However, the existing differentiation protocols are complex, time-consuming, and costly; thus there is a need for alternative protocols. Given the common developmental origins of liver and pancreas, we sought to develop a novel protocol, devoid of growth factors, by using liver stromal cells (LSCs) derived from human fetal liver. We examined the effects of the LSCs on the differentiation of pancreatic progenitor cells (PPCs) into islet-like cell clusters (ICCs). PPCs and LSCs isolated from 1st to 2nd trimester human fetal tissues underwent co-cultures; differentiation and functionality of ICCs were determined by examining expression of critical markers and secretion of insulin. Co-culture with 2nd but not 1st trimester LSCs enhanced ICC differentiation and functionality without the use of exogenous differentiation 'cocktails'. Differential expression profiles of growth factors from 1st versus 2nd trimester fetal liver were compared. Many morphogenic factors were expressed by LSCs, while insulin-like growth factor 1 (IGF1) was identified as one of the key molecules responsible for the ICC differentiation. This is the first report showing that an LSC-induced microenvironment can enhance ICC differentiation and functionality. Further modifications of the stroma microenvironment may offer an alternative, efficient and cost-effective approach to providing islets for transplantation.

Exogenous augmenter of liver regeneration (ALR) attenuates inflammatory response in renal hypoxia re-oxygenation injury

Recent studies have highlighted the role of the innate immune system in initiating the inflammatory cascade which leads to detrimental changes in renal ischemia reperfusion (I/R) injury. The augmenter of liver regeneration (ALR) is an anti-apoptosis factor which is highly expressed in renal tubulars of renal cortex and medulla after inducing renal I/R injury in rats. It has been shown that exogenous ALR can enhance renal tubular regeneration. However, whether ALR's protective effect against renal I/R injury results from its immune regulatory function remains unknown. Using rat renal tubular epithelial cell (NRK-52E), we investigate the effect of recombinant rat ALR (rrALR) on immune inflammatory response in hypoxia re-oxygenation (H/R) injury in vitro, and further discuss the possible mechanisms. Cultured NRK-52E cells subjected to hypoxia for 6 h followed by re-oxygenation for 12, 24 and 72 h are administered with different doses of rrALR. Expression of Toll-like receptor 4 (TLR4) and transcription nuclear factor-κB (NF-κB) is assessed by reverse-transcriptase polymerase chain reaction (RT-PCR) and western blot. Expression of interleukin (IL)-6 and IL-1β are determined by enzyme-linked immunosorbent assay (ELISA). In rrALR intervened H/R cells, TLR4 and NF-κB are down regulated at both mRNA and protein levels compare with those in control cells. Also, rrALR appears to downregulate IL-6 and IL-1β expression in concentration-dependent manners. In conclusion, rrALR protects NRK-52E cells from H/R injury possibly by relieving the inflammatory response through regulation of TLR4-NF-κB signaling pathway.

Augmenter of liver regeneration (ALR) is a novel biomarker of hepatocellular stress/inflammation: in vitro, in vivo and in silico studies

The liver is a central organ involved in inflammatory processes, including the elaboration of acute-phase proteins. Augmenter of liver regeneration (ALR) protein, expressed and secreted by hepatocytes, promotes liver regeneration and maintains viability of hepatocytes. ALR also stimulates secretion of inflammatory cytokines (tumor necrosis factor [TNF]-α and interleukin [IL]-6) and nitric oxide from Kupffer cells. We hypothesized that ALR may be involved in modulating inflammation induced by various stimuli. We found that hepatic ALR levels are elevated at 24 h, before or about the same time as an increase in the mRNA expression of TNF-α and IL-6, after portacaval shunt surgery in rats. Serum ALR also increased, but significantly only on d 4 when pathological changes in the liver become apparent. In rats, serum ALR was elevated after intraperitoneal administration of lipopolysaccharide alone and in a model of gram-negative sepsis. Serum ALR increased before alanine aminotransferase (ALT) in endotoxemia and in the same general time frame as TNF-α and IL-6 in the bacterial sepsis model. Furthermore, mathematical prediction of tissue damage correlated strongly with alterations in serum ALR in a mouse model of hemorrhagic shock. In vitro, monomethyl sulfonate, TNF-α, actinomycin D and lipopolysaccharide all caused increased release of ALR from rat hepatocytes, which preceded the loss of cell viability and/or inhibition of DNA synthesis. ALR may thus serve as a potential diagnostic marker of hepatocellular stress and/or acute inflammatory conditions.

Augmenter of liver regeneration

'Augmenter of liver regeneration' (ALR) (also known as hepatic stimulatory substance or hepatopoietin) was originally found to promote growth of hepatocytes in the regenerating or injured liver. ALR is expressed ubiquitously in all organs, and exclusively in hepatocytes in the liver. ALR, a survival factor for hepatocytes, exhibits significant homology with ERV1 (essential for respiration and viability) protein that is essential for the survival of the yeast, Saccharomyces cerevisiae. ALR comprises 198 to 205 amino acids (approximately 22 kDa), but is post-translationally modified to three high molecular weight species (approximately 38 to 42 kDa) found in hepatocytes. ALR is present in mitochondria, cytosol, endoplasmic reticulum, and nucleus. Mitochondrial ALR may be involved in oxidative phosphorylation, but also functions as sulfhydryl oxidase and cytochrome c reductase, and causes Fe/S maturation of proteins. ALR, secreted by hepatocytes, stimulates synthesis of TNF-α, IL-6, and nitric oxide in Kupffer cells via a G-protein coupled receptor. While the 22 kDa rat recombinant ALR does not stimulate DNA synthesis in hepatocytes, the short form (15 kDa) of human recombinant ALR was reported to be equipotent as or even stronger than TGF-α or HGF as a mitogen for hepatocytes. Altered serum ALR levels in certain pathological conditions suggest that it may be a diagnostic marker for liver injury/disease. Although ALR appears to have multiple functions, the knowledge of its role in various organs, including the liver, is extremely inadequate, and it is not known whether different ALR species have distinct functions. Future research should provide better understanding of the expression and functions of this enigmatic molecule.

Novel developmental biology-based protocol of embryonic stem cell differentiation to morphologically sound and functional yet immature hepatocytes

BACKGROUND/AIMS

Liver diseases are common in the United States and often require liver transplantation; however, donated organs are limited and thus alternative sources for liver cells are in high demand. Embryonic stem cells (ESC) can provide a continuous and readily available source of liver cells. ESC differentiation to liver cells is yet to be fully understood and comprehensive differentiation protocols are yet to be defined. Here, we aimed to achieve human (h)ESC differentiation into mature hepatocytes using defined recombinant differentiation factors and metabolites.

METHODS

Embryonic stem cell H1 line was sub-cultured on feeder layer. We induced hESCs into endodermal differentiation succeeded by early/late hepatic specification and finally into hepatocyte maturation using step combinations of Activin A and fibroblast growth factor (FGF)-2 for 7 days; followed by FGF-4 and bone morphogenic protein 2 (BMP2) for 7 days, succeeded by FGF-10 + hepatocyte growth factor 4 + epidermal growth factor for 14 days. Specific inhibitors/stimulators were added sequentially throughout differentiation. Cells were analysed by PCR, flow cytometry, microscopy or functional assays.

RESULTS

Our hESC differentiation protocol resulted in viable cells with hepatocyte shape and morphology. We observed gradual changes in cell transcriptome, including up-regulation of differentiation-promoting GATA4, GATA6, POU5F1 and HNF4 transcription factors, steady levels of stemness-promoting SOX-2 and low levels of Nanog, as defined by PCR. The hESC-derived hepatocytes expressed alpha-antitrypsin, CD81, cytokeratin 8 and low density lipoprotein (LDL) receptor. The levels of alpha-fetoprotein and proliferation marker Ki-67 in hESC-derived hepatocytes remained elevated. Unlike stem cells, the hESC-derived hepatocytes performed LDL uptake, produced albumin and alanine aminotransferase and had functional alcohol dehydrogenase.

CONCLUSION

We report a novel protocol for hESC differentiation into morphological and functional yet immature hepatocytes as an alternative method for hepatocyte generation.

Recombinant hepatocyte growth factor treatment in a canine model of congenital liver hypoplasia

BACKGROUND

Although the liver has a large regenerative capacity, in many hepatopathies, these repair mechanisms fail. The therapeutic potential of hepatocyte growth factor (HGF) has been proven in numerous toxin-induced liver failure models in rodents, but never in spontaneously occurring liver diseases in larger animal models.

AIM

The aim of this study was to induce liver growth in a hypoplastic liver by the administration of exogenous recombinant HGF. The natural hypoplastic liver model used is the canine congenital portosystemic shunt (CPSS) characterized by strongly reduced liver growth and function.

METHODS

Recombinant HGF (rHGF), 200 μg/kg, was given twice daily during 3 weeks by an intravenous injection in six dogs with CPSS. Liver volumes were determined by computed tomography before and at 1, 2, 3 and 7 weeks after the initiation of treatment. Portosystemic shunting was evaluated with an ammonia tolerance test and liver portal perfusion was quantified with scintigraphy. Simultaneously, blood parameters for liver function were assayed and liver biopsies were taken for histology, immunohistochemistry and gene-expression measurements.

RESULTS

During 3 weeks of HGF treatment, hepatocyte proliferation increased and an increase in liver volume up to 44% was seen, persisting in two dogs up to 4 weeks after the termination of treatment. Ki-67 expression, gene expression of E2F1 and CDC6, phosphorylated-c-MET and phosphorylated-ERK1/2 protein levels confirmed increased hepatocyte proliferation and HGF signalling. The aberrant portal perfusion did not change during treatment.

CONCLUSIONS

Transient in vivo liver growth is shown using CPPS as a naturally occurring large animal model, indicating the therapeutic potential of HGF in liver disease.

Epidermal growth factor down-regulates the expression of human hepatic stimulator substance via CCAAT/enhancer-binding protein β in HepG2 cells

hHSS (human hepatic stimulator substance), acting as a hepatotrophic growth factor, promotes liver regeneration. However, the regulatory mechanisms for hHSS transcription are still poorly understood. In the present study, we investigated transcription of hHSS triggered by EGF (epidermal growth factor) and the role of C/EBPβ (CCAAT/enhancer-binding protein β) as a potential core factor responsible for hHSS transcription in HepG2 cells. The results show that EGF suppresses hHSS mRNA expression at early time points. Using a promoter deletion assay, we identified a proximal region (−358/−212) that is required for EGF suppression. Overexpression of C/EBPβ enhances EGF suppression of hHSS, and mutation of the C/EBPβ-binding site at −292/−279 or siRNA (short interfering RNA) interference abolishes EGF suppression. Furthermore, using an electrophoretic mobility-shift assay and chromatin immunoprecipitation analysis, we found that C/EBPβ specifically binds to the −292/−279 site that is responsible for EGF inhibition. Moreover, using a knockin (overexpression) and knockdown strategy (siRNA), we confirmed that C/EBPβ is a key factor responsible for inhibition of hHSS mRNA expression. Pre-treatment with an inhibitor of JNK (c-Jun N-terminal kinase) or down-regulation of JNK1 with specific siRNA reverses EGF-inhibited hHSS expression. Our results provide a crucial regulatory mechanism for EGF in hHSS transcription within the promoter proximal region.

Foxa2 (HNF-3beta) regulates expression of hepatotrophic factor ALR in liver cells

Liver regeneration is a multistep and well-orchestrated process which is initiated by injuries such as tissue loss, infectious or toxic insults. Augmenter of liver regeneration (ALR) is a hepatotrophic growth factor which has been shown to stimulate hepatic regeneration after partial hepatectomy and therefore seems to be regulated during the regenerative process in the liver. Our aim was to analyze how ALR is regulated in hepatic tissues and which transcription factors might regulate its tissue-specific expression. Promoter studies of ALR (-733/+527 bp) revealed potential regulatory elements for various transcription factors like Foxa2, IL-6 RE-BP and C/EBPbeta. Analysis of the promoter activity by performing luciferase assays revealed that co-transfection with Foxa2 significantly induced the activity of ALR promoter in HepG2 cells. EMSA and Supershift analysis using anti-Foxa2 antibody confirmed the specific binding of Foxa2 to ALR promoter and this binding was inducible when the cells were simultaneously stimulated with IL-6. The increased binding after activation with IL-6 and/or Foxa2 was confirmed by elevated ALR protein levels using Western blot technique. In addition, we could not detect any binding of C/EBPbeta and IL-6 RE-BP to the promoter of ALR. In conclusion, these results indicate that ALR is regulated by Foxa2, and this regulation may be amplified by IL-6.

Cholera toxin-sensitive GTP-binding protein-coupled activation of augmenter of liver regeneration (ALR) receptor and its function in rat kupffer cells

Mitogenic effect of augmenter of liver regeneration (ALR), a protein produced and released by hepatocytes, on hepatocytes in vivo but not in vitro suggests that the effect is mediated by nonparenchymal cells. Since mediators produced by Kupffer cells are implicated in hepatic regeneration, we investigated receptor for ALR and its functions in rat Kupffer cells. Kupffer cells were isolated from rat liver by enzymatic digestion and centrifugal elutriation. Radioligand ([(125)I] ALR) receptor binding, ALR-induced GTP/G-protein association, and nitric oxide (NO), tumor necrosis factor (TNF)-alpha, and interleukin-6 (IL-6) synthesis were determined. High-affinity receptor for ALR, belonging to the G-protein family, with K(d) of 1.25 +/- 0.18 nM and B(max) of 0.26 +/- 0.02 fmol/microg DNA was identified. ALR stimulated NO, TNF-alpha, and IL-6 synthesis via cholera toxin-sensitive G-protein, as well as p38-MAPK activity and nuclear translocation of NFkappaB. While inhibitor of NFkappaB (MG132) inhibited ALR-induced NO synthesis, MG132 and p38-MAPK inhibitor (SB203580) abrogated ALR-induced TNF-alpha and IL-6 synthesis. ALR also prevented the release of mediator(s) from Kupffer cells that cause inhibition of DNA synthesis in hepatocytes. Administration of ALR to 40% partially hepatectomized rats increased expression of TNF-alpha, IL-6, and inducible nitric oxide synthase (iNOS) and caused augmentation of hepatic regeneration. These results demonstrate specific G-protein coupled binding of ALR and its function in Kupffer cells and suggest that mediators produced by ALR-stimulated Kupffer cells may elicit physiologically important effects on hepatocytes.

Human augmenter of liver regeneration: Molecular cloning, biological activity and roles in liver regeneration

The complete amino acid sequence of human augmenter of liver regeneration (hALR) was reported by deduction from nucleotide sequence of its complementary DNA. The cDNA for hALR was isolated by screening a human fetal liver cDNA library and the sequencing of this insert revealed an open reading frame encoding a protein with 125aa and highly homologous (87%) with rat ALR encoding sequence. The recombinant hALR expressed from its cDNA in transient expression experiments in cos-7 cells could stimulate DNA synthesis of HTC hepatoma cell in the dose-dependent and heat-resistant way. Northern blot analysis with rat ALR cDNA as probe confirmed that ALR mRNA was expressed in the normal rat liver at low level and that dramatically increased in the regenerating liver after partial hepatectomied rat. This size of hALR mRNA is 1.4 kb long and expressed in human fetal liver, kidney and testis. These findings indicated that liver itself may be the resource of ALR and suggested that ALR seems to be an important paracrined regulator of liver regeneration.

Augmenter of liver regeneration: an important intracellular survival factor for hepatocytes

BACKGROUND/AIMS

Augmenter of liver regeneration (ALR), a protein synthesized and stored in hepatocytes, is associated with mitochondria, and possesses sulfhydryl oxidase and cytochrome c reductase activities. We sought to determine the effects of ALR depletion in hepatocytes by antisense oligonucleotide transfection.

METHODS

Rat hepatocytes in primary culture were transfected with antisense oligonucleotide for ALR mRNA (ALR-AS) or scrambled oligonucleotide. Various analyses were performed at times up to 24h after transfection.

RESULTS

Treatment with ALR-AS caused a decrease in ALR mRNA, cellular depletion of ALR protein primarily from mitochondria, and decreased viability. Flow cytometric analysis of ALR-AS-transfected hepatocytes stained with annexin-Vcy3 and 7-aminoactinomycin D revealed apoptosis as the predominant cause of death up to 6h; incubation beyond this time resulted in necrosis in addition to apoptosis. ALR-AS-transfection caused release of mitochondrial cytochrome c, activation of caspase-3, profound reduction in the ATP content, and cellular release of LDH. Inhibition of caspase-3 inhibited the early phase of ALR-AS-induced death but not the late phase that included ALR and LDH release.

CONCLUSIONS

These results suggest that ALR is critically important for the survival of hepatocytes by its association with mitochondria and regulation of ATP synthesis.

Insights on augmenter of liver regeneration cloning and function

Hepatic stimulator substance (HSS) has been referred to as a liver-specific but species non-specific growth factor. Gradient purification and sequence analysis of HSS protein indicated that it contained the augmenter of liver regeneration (ALR), also known as hepatopoietin (HPO). ALR, acting as a hepatotrophic growth factor, specifically stimulated proliferation of cultured hepatocytes as well as hepatoma cells in vitro, promoted liver regeneration and recovery of damaged hepatocytes and rescued acute hepatic failure in vivo. ALR belongs to the new Erv1/Alr protein family, members of which are found in lower and higher eukaryotes from yeast to man and even in some double-stranded DNA viruses. The present review article focuses on the molecular biology of ALR, examining the ALR gene and its expression from yeast to man and the biological function of ALR protein. ALR protein seems to be non-liver-specific as was previously believed, increasing the necessity to extend research on mammalian ALR protein in different tissues, organs and developmental stages in conditions of normal and abnormal cellular growth.

Identification of human hepatic stimulator substance gene promoter and demonstration of dual regulation of AP1/AP4 cis-acting element in different cell lines

Human hepatic stimulator substance (hHSS) is a newly identified growth-promoting factor in the liver. HSS is capable of stimulating hepatic regeneration in partial hepatectomized rats, thus, promoting growth of hepatic tumor cells. To understand and elucidate the transcriptional regulation of hHSS gene, the 4890bp of 5'-flanking region of the gene have been isolated and sequenced. The transcriptional start site, located at 248nt upstream from the ATG starting codon, was identified by 5'-rapid amplification cDNA end (5'-RACE). The classical promoter sequences, such as TATA box or GAATT were not identified in the promoter region, instead a GC-rich segment was formed (>70%) by expanding to a longer than 400bp, and immediately upstream from the ATG start codon. The transient transfection assays, using promoter deletion constructs, showed that hHSS promoter was efficiently capable in driving the reporter expression not only in HepG2 cells, but also in Cos7 cells. A region spanning nucleotides in the range of -447 to -358bp revealed a negative regulation on promoter activity in HepG2 cells, but with positive regulation in Cos7 and Hela cells. The promoter activity was obviously influenced by AP1/AP4 (-375/-369nt) mutation in these three cell lines. EMSAs showed that the site was recognized by AP1 in HepG2 cell, and only by an AP4 protein in Cos7 cells. The c-Jun bound to the promoter was further verified by supershift in HepG2 cells and human liver tissue. Chromatin immuno-precipitation (ChIP) demonstrated that there was a direct association of c-Jun with hHSS promoter in HepG2 cells. The c-Jun strongly suppressed hHSS promoter activity in transient expression analyses in HepG2 cells. Mutations in the AP1 binding sites rescued suppression caused by c-Jun, suggesting this was a direct regulation of the hHSS promoter. In contrast, there was no significant effect in c-Jun over-expressed Cos7 and Hela cells. The tissue-specific function of c-Jun in hHSS promoter activity may in part help explain the differences in biology function of hHSS between liver and non-liver cells.

Chronic hepatitis in dogs: a review of current understanding of the aetiology, progression, and treatment

Chronic hepatitis is common in dogs in primary and referral practice but the cause is usually unknown. This paper reviews the literature on potential causes of chronic hepatitis in dogs (infectious, autoimmune, metabolic, toxic, and breed-associated) together with the literature on the progression of the disease and on treatments. This is compared with the current understanding of aetiology, progression, and treatment of chronic hepatitis in man. Unfortunately, little is known about the aetiology and progression of the canine disease and very few therapies have been subjected to critical trials. It is difficult therefore to draw conclusions about causes and effective treatment in dogs. Even the histological description for canine chronic hepatitis has yet to be standardised. Much research remains to be done and this review suggests some potential areas for future investigation.

History of clinical transplantation

The emergence of transplantation has seen the development of increasingly potent immunosuppressive agents, progressively better methods of tissue and organ preservation, refinements in histocompatibility matching, and numerous innovations in surgical techniques. Such efforts in combination ultimately made it possible to successfully engraft all of the organs and bone marrow cells in humans. At a more fundamental level, however, the transplantation enterprise hinged on two seminal turning points. The first was the recognition by Billingham, Brent, and Medawar in 1953 that it was possible to induce chimerism-associated neonatal tolerance deliberately. This discovery escalated over the next 15 years to the first successful bone marrow transplantations in humans in 1968. The second turning point was the demonstration during the early 1960s that canine and human organ allografts could self-induce tolerance with the aid of immunosuppression. By the end of 1962, however, it had been incorrectly concluded that turning points one and two involved different immune mechanisms. The error was not corrected until well into the 1990s. In this historical account, the vast literature that sprang up during the intervening 30 years has been summarized. Although admirably documenting empiric progress in clinical transplantation, its failure to explain organ allograft acceptance predestined organ recipients to lifetime immunosuppression and precluded fundamental changes in the treatment policies. After it was discovered in 1992 that long-surviving organ transplant recipients had persistent microchimerism, it was possible to see the mechanistic commonality of organ and bone marrow transplantation. A clarifying central principle of immunology could then be synthesized with which to guide efforts to induce tolerance systematically to human tissues and perhaps ultimately to xenografts.

A fresh look at augmenter of liver regeneration in rats

Augmenter of liver regeneration (ALR) is a hepatotrophic protein originally identified by bioassay in regenerating rat and canine livers following partial hepatectomy and in the hyperplastic livers of weanling rats, but not in resting adult livers. The ALR gene and gene product were subsequently described, but little is known about the cellular/subcellular sites of ALR synthesis in the liver, or about the release and dissemination of the peptide. To obtain this information in rats, we raised antibodies in rabbits against rat ALR for development of an enzyme-linked immunosorbent assay (ELISA). ALR concentrations were then determined in intact livers of unaltered weanling and adult rats; in regenerating residual liver after partial hepatectomy; in cultured hepatocytes and nonparenchymal cells (NPCs); and in culture medium and serum. ALR in the various liver cells was localized with immunohistochemistry. In addition, hepatic ALR and ALR mRNA were assayed with Western blotting and reverse-transcriptase polymerase chain reaction (RT-PCR), respectively. The hepatocyte was the predominant liver cell in which ALR was synthesized and stored; the cultured hepatocytes secreted ALR into the medium in a time-dependent fashion. Contrary to previous belief, the ALR peptide and ALR mRNA were present in comparable concentrations in the hepatocytes of both weanling and resting adult livers, as well as in cultured hepatocytes. A further unexpected finding was that hepatic ALR levels decreased for 12 hours after 70% hepatectomy in adult rats and then rose with no corresponding change in mRNA transcripts. In the meantime, circulating (serum) ALR levels increased up to 12 hours and declined thereafter. Thus, ALR appears to be constitutively expressed in hepatocytes in an inactive form, and released from the cells in an active form by unknown means in response to partial hepatectomy and under other circumstances of liver maturation (as in weanling rats) or regeneration.

Crystallization and preliminary crystallographic data for the augmenter of liver regeneration

A new cellular growth factor termed augmenter of liver regeneration (ALR) has been crystallized. ALR has been shown to have a proliferative effect on liver cells while at the same time producing an immunosuppressive effect on liver-resident natural killer cells and liver-resident mononuclear leukocytes. In addition, ALR appears to play an important role in the synthesis and stabilization of mitochondrial gene transcripts in actively regenerating cells. ALR crystals diffract to beyond 2 A resolution and belong to space group P2(1)2(1)2, with a = 125.1, b = 108.1 and c = 38.5 A. Based on four molecules per asymmetric unit, the Matthews coefficient is calculated to be 2.16 A(3) Da(-1) which corresponds to a solvent content of 43%.

Hepatocyte transplantation as a bridge to orthotopic liver transplantation in terminal liver failure

The limited donor organ supply has led to several bridging techniques to sustain patients with acute and subacute liver failure. We report here the prospective, controlled trial of transplanted isolated fresh and cryopreserved human hepatocytes as a bridge to orthotopic liver transplantation. Five hepatocyte transplant recipients with grade IV encephalopathy and multisystem organ failure and four patients of equal illness severity due to liver failure were studied. Medical therapy resulted in a significant (P<0.05), but not normal, fall in blood ammonia, and a significant (P<0.02) resolving biochemical marker of liver injury that did not improve cardiovascular or cerebral stability; this lead to death within 3 days in all control patients. The five hepatocyte-treated patients maintained normal cerebral perfusion and cardiac stability, with withdrawal of medical support for 2 to 10 days before orthotopic liver transplantation. Biochemical evidence of liver injury improved significantly (P=0.004) and blood ammonia levels decreased significantly (P=0.0005) to normal levels in the hepatocyte-treated patients. Three of five patients who successfully bridged to whole liver allograft transplant are alive, home, and normal with more than 20 months of follow-up. No infections or embolic or pulmonary complications resulted from intra-arterial splenic hepatocyte infusion. Specific antiprotease production in a patients with genetically deficient alpha-1-antitrypsin disease, and immunohistochemical and electron microscopic evidence of splenic "hepatization" are presented as evidence of the viability of hepatocyte splenic seeding. In conclusion, splenic transplantation of differentiated adult hepatocytes can control hyper-ammonemia, correct genetic defects in liver function, and bridge life to orthotopic liver transplantation in human liver failure.

The in vivo effect of hepatotrophic factors augmenter of liver regeneration, hepatocyte growth factor, and insulin-like growth factor-II on liver natural killer cell functions

Fine balanced sequential changes of the levels of circulating hepatotrophic factors are essential for normal liver regeneration. Our recent studies have indicated that liver-resident natural killer (NK) cells are important regulators of liver regeneration and have raised the possibility that hepatotrophic factors might mediate their activities through NK cells. In the present study, we assessed the effects of in vivo administration of three hepatotrophic factors (augmenter of liver regeneration [ALR], insulin-like growth factor-II [IGF-II], and hepatocyte growth factor [HGF]) on NK cells in normal rats. Each of the three, given over a 1-day period in doses known to produce hepatotrophic activity, induced inhibition of NK cell cytotoxic activities in the population of mononuclear leukocytes (MNL) in the liver, but not in MNL from the spleen or peripheral blood. In contrast to these results obtained by the whole animal treatment, the three molecules had no effect on NK cell functions when added to cultures of MNL from the livers, spleens, or blood of untreated rats. These data support and extend our previously advanced hypothesis that ALR and other hepatotrophic factors play an important role in liver regeneration by regional regulation of NK cells through some as-yet-unknown intermediary mechanism.

The in vivo effect of hepatotrophic factors augmenter of liver regeneration, hepatocyte growth factor, and insulin-like growth factor-II on liver natural killer cell functions

Fine balanced sequential changes of the levels of circulating hepatotrophic factors are essential for normal liver regeneration. Our recent studies have indicated that liver-resident natural killer (NK) cells are important regulators of liver regeneration and have raised the possibility that hepatotrophic factors might mediate their activities through NK cells. In the present study, we assessed the effects of in vivo administration of three hepatotrophic factors (augmenter of liver regeneration [ALR], insulin-like growth factor-II [IGF-II], and hepatocyte growth factor [HGF]) on NK cells in normal rats. Each of the three, given over a 1-day period in doses known to produce hepatotrophic activity, induced inhibition of NK cell cytotoxic activities in the population of mononuclear leukocytes (MNL) in the liver, but not in MNL from the spleen or peripheral blood. In contrast to these results obtained by the whole animal treatment, the three molecules had no effect on NK cell functions when added to cultures of MNL from the livers, spleens, or blood of untreated rats. These data support and extend our previously advanced hypothesis that ALR and other hepatotrophic factors play an important role in liver regeneration by regional regulation of NK cells through some as-yet-unknown intermediary mechanism.

Analysis of the structure and expression of the augmenter of liver regeneration (ALR) gene

BACKGROUND

The gene encoding the hepatotrophic factor Augmenter of Liver Regeneration (ALR) has recently been cloned in the rat. The availability of the mouse form of ALR would allow the analysis of the role of this factor in the physiology of liver and other organs, while the identification of the human homolog would allow the transfer of the great wealth of information that has been generated in animal models to clinically oriented pilot trials, and eventually the therapeutic application of this information.

MATERIALS AND METHODS

Standard molecular biology approaches have been used to determine the genomic structure of the ALR gene in the mouse, and to characterize the ALR transcript and its protein product. The human ALR cDNA was also isolated and the amino acid sequence of the human gene product deduced. The mapping of mouse and human ALR genes on mouse and human chromosomes was then completed.

RESULTS

The protein coding portion of the mouse ALR gene is comprised of three exons, the first containing the 5' untranslated sequence and the initial 18 bases after the ATG translation initiation codon, the second exon encompasses 198 bases, and the third exon contains the remaining portion of the protein coding sequence. Rat, mouse, and human ALR genes (and protein products) were found to be highly conserved and preferentially expressed in the testis and in the liver. The ALR gene maps to the mouse chromosome 17, in a region syntenic with human chromosome 16, where the T/t region has also been mapped.

CONCLUSIONS

ALR appears to be a protein with important physiologic properties, not exclusively limited to liver regeneration, with roles that are involved in the synthesis or stability of the nuclear and mitochondrial transcripts that are present in actively regenerating cells, particularly the germ cells of the testes.

Liver regeneration following partial hepatectomy and stimulation by hepatic stimulatory substance in cirrhotic and non-cirrhotic rats

The effects of hepatic stimulatory substance (HSS) on cirrhotic and non-cirrhotic rats were studied after 70% partial hepatectomy. Liver cirrhosis was produced by weekly intragastric infusion of chloroform for 12-16 weeks. The HSS was prepared by extraction from the livers of weanling mice. Rats in the experimental group were injected with 5 ml HSS after 70% partial hepatectomy, and those in the control group received normal saline. The results showed that the 3H-thymidine incorporation was higher in the HSS group 24 h after partial hepatectomy in both cirrhotic and non-cirrhotic rats, and persistently higher in the non-cirrhotic rats at 48 h. Total DNA was significantly higher in the HSS group of non-cirrhotic rats 24 and 48 h after partial hepatectomy. The restituted liver volume and weight was significantly higher in non-cirrhotic rats 48 h after partial hepatectomy, while there was no significant difference between the HSS and the control groups in the cirrhotic rats. The HSS induced significant effects on 3H-thymidine incorporation in the non-cirrhotic liver, resulting in increasing liver weight, volume and total DNA 48 h after partial hepatectomy. In cirrhotic rats, the 3H-thymidine incorporation was higher in the HSS group at 24 h after partial hepatectomy, though not showing any increase at 48 h, but the regeneration of liver weight, volume and total DNA at 48 h showed no difference between the HSS group and the control group.

Cloning and sequence analysis of the rat augmenter of liver regeneration (ALR) gene: expression of biologically active recombinant ALR and demonstration of tissue distribution

A full-length cDNA clone encoding a purified augmenter of liver regeneration (ALR) factor prepared from the cytosol of weanling rat livers was isolated. The 1.2-kb cDNA included a 299-bp 5' untranslated region, a 375-bp coding region, and a 550-bp 3' untranslated region. It encoded a protein consisting of 125 amino acids. The molecular weight of ALR calculated from the cDNA was 15,081, which is consistent with the size estimated by SDS/PAGE under reducing conditions. The molecular weight of the purified native ALR estimated by SDS/PAGE under nonreducing conditions was approximately 30,000; thus ALR apparently has a homodimeric structure. The recombinant ALR produced by expression of the cDNA in COS cells was tested in vivo in the canine Eck fistula model and found to have potency equivalent to the purified native ALR. The 125-aa sequence deduced from the rat ALR cDNA shows 50% homology to the amino acid sequence of the gene for oxidative phosphorylation and vegetative growth in the yeast Saccharomyces cerevisiae.

Human hepatic stimulator substance: a product of gene expression of human fetal liver tissue

Cloning of human hepatic stimulator substance requires clarification of whether the substance is the product of gene expression of liver cells. In this article the translation experiment in Xenopus laevis oocytes indicates that poly (A)+ messenger RNA of human fetal liver cells could conduct the biosynthesis of human hepatic stimulator substance. The translated human hepatic stimulator substance is a heat-, acid- and alkaline-resistant, but specific hepatic-stimulating, protein with a molecular weight in the range of 10 to 30 kD and with secreting ability. The characteristics of the translated human hepatic stimulator substance are consistent with those of biochemically purified human hepatic stimulator substance from human fetal liver cells. These results demonstrate that human hepatic stimulator substance is a product of gene expression of human fetal liver cells and that the complementary DNA of human hepatic stimulator substance could be screened from the complementary DNA library of human fetal liver tissue.

Apoptosis of serum-free C2.8 mouse embryo hepatocytic cells caused by hepatocyte growth factor deprivation

C2.8 mouse embryo hepatocytic cells, acutely required exogenous hepatocyte growth factor (HGF) to survive and proliferate in serum-free Dulbecco's modified Eagle's medium supplemented with insulin, transferrin and Na-selenite. Greater than 90% of cultured C2.8 cells died within 48 hours from plating in the absence of HGF. Conversely, HGF prolonged maintenance of life and stimulated cell proliferation. Removal of HGF from the medium of cultures that had grown to confluency, also resulted in a rapid decreased cell survival. In the last circumstance, light microscopic observations revealed, with high frequency, morphological features characteristic of apoptosis. DNA within the affected cells underwent rapid fragmentation, revealed as a ladder of DNA fragments in multiples of about 200 base pairs. HGF prevented loss of cell viability, morphological damages and retarded DNA fragmentation in confluent C2.8 cells. Cycloheximide delayed cell death caused by HGF deprivation.

Cytoprotective effect of somatostatin in a rat model of hepatic ischemic reperfusion

To evaluate the possible cytoprotective effect of somatostatin in hepatic ischemic reperfusion injury we used 75 adult male Wistar rats randomly separated into four groups. The rats in group 1 underwent sham operations, and those in group 2 underwent resection of the median and left lateral lobes. The rats in group 3 underwent a 90-min period of ischemia of the right lateral lobe, which we induced by temporarily occluding the right portal vein and the hepatic artery. On restoration of flow to the right lateral lobe, the median and left lateral lobes (about 80% of total liver mass) were excised (and later assayed for thymidine kinase basal activity). The rats in group 4 were given the same treatment as group 3 rats except that a saline solution of somatostatin was infused at a rate of 2 micrograms/min starting at laparotomy and lasting 24 hr. The rats in groups 1, 2 and 3 were infused with saline. Rats in groups 2, 3 and 4 were randomly assigned to two subgroups; one of these subgroups was observed until spontaneous death, and rats in the other group were killed 24 hr after the procedure for obtaining peripheral blood and liver samples. Somatostatin infusion improved the animals' survival rates from 0% (group 3) to 60% (group 4) (p < 0.05) and decreased bilirubin levels (0.78 +/- 0.17 mg/dl, n = 15 [group 4] vs. 1.69 +/- 0.04 mg/dl, n = 15 [group 3]; p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect on the canine Eck fistula liver of intraportal TGF-beta alone or with hepatic growth factors

Transforming growth factor-beta canceled the hepatocyte proliferation caused by transforming growth factor-alpha when the two substances were mixed and administered through a disconnected central portal vein branch after creation of an Eck fistula. In contrast, transforming growth factor-beta had no antidotal action on the stimulatory effects of insulin or full test doses of insulinlike factor-2, hepatocyte growth factor, epidermal growth factor or triiodothymanine. A minor antidotal effect on hepatic stimulatory substance activity could be detected, but only with hepatic stimulatory substance was given in doses smaller than those known to cause maximum stimulatory response. These results suggest a highly specific pharmacological and physiological interaction between transforming growth factor-alpha and transforming growth factor-beta in the modulation of liver growth control.

Prostaglandin E2 production during hepatic regeneration downregulates Kupffer cell IL-6 production

The liver possesses the remarkable ability to regenerate to its original size after a 70% partial hepatectomy. There has been little effort to characterize the Kupffer cells' role in this unique mammalian reparative physiologic phenomenon. The capacity of rat Kupffer cells (KC) isolated at specific intervals after partial hepatectomy to produce interleukin-6 (IL-6) and prostaglandin E2 (PGE2) in response to endotoxin was evaluated in standard RPMI-1640 (1200 microM L-arginine) and arginine-depleted RPMI-1640 (10 microM L-arginine) media. Regenerating liver KC 48 to 120 hours after partial hepatectomy responded to endotoxin stimulation with a significantly greater (p less than 0.05) production of IL-6 in standard RPMI-1640. Because Kupffer cells function in an environment where high arginase activity results in negligible L-arginine levels, the 10 microM L-arginine RPMI-1640 was used to simulate the true hepatic microenvironment. Production of IL-6 by regenerating liver KC was further increased (p less than 0.05) by placing these same KC in 10 microM L-arginine RPMI-1640 tissue culture media. During the same period, regenerating liver KC produced significantly (p less than 0.01) more PGE2 than sham-operated KC in both standard and low-arginine media. When the cyclo-oxygenase inhibitor indomethacin (1 x 10(-5) M) was added to cultures, the PGE2 production was inhibited, and IL-6 production was upregulated (p less than 0.05) in arginine-depleted cultures. The authors conclude that during hepatic regeneration KC IL-6 production is elevated but controlled in an autoregulatory fashion by KC PGE2 production.

Screening for candidate hepatic growth factors by selective portal infusion after canine Eck's fistula

Completely diverting portacaval shunt (Eck's fistula) in dogs causes hepatocyte atrophy, disruption of hepatocyte organelles, fatty infiltration and low-grade hyperplasia. The effect of hepatic growth regulatory substances on these changes was assessed by constantly infusing test substances for four postoperative days after Eck's fistula into the detached left protal vein above the shunt. The directly infused left lobes were compared histopathologically with the untreated right lobes. In what has been called an hepatotrophic effect, stimulatory substances prevented the atrophy and increased hepatocyte mitoses. Of the hormones tested, only insulin was strongly hepatotrophic; T3 had a minor effect, and glucagon, prolactin, angiotensin II, vasopressin, norepinephrine and estradiol were inert. Insulin-like growth factor, hepatic stimulatory substance, transforming growth factor-alpha and hepatocyte growth factor (also known as hematopoietin A) were powerfully hepatotrophic, but epidermal growth factor had a barely discernible effect. Transforming growth factor-beta was inhibitory, but tamoxifen, interleukin-1 and interleukin-2 had no effect. The hepatotrophic action of insulin was not altered when the insulin infusate was mixed with transforming growth factor-beta or tamoxifen. These experiments show the importance of in vivo in addition to in vitro testing of putative growth control factors. They illustrate how Eck's fistula model can be used to screen for such substances and possibly to help delineate their mechanisms of action.

Screening for candidate hepatic growth factors by selective portal infusion after canine Eck's fistula

Completely diverting portacaval shunt (Eck's fistula) in dogs causes hepatocyte atrophy, disruption of hepatocyte organelles, fatty infiltration and low-grade hyperplasia. The effect of hepatic growth regulatory substances on these changes was assessed by constantly infusing test substances for four postoperative days after Eck's fistula into the detached left protal vein above the shunt. The directly infused left lobes were compared histopathologically with the untreated right lobes. In what has been called an hepatotrophic effect, stimulatory substances prevented the atrophy and increased hepatocyte mitoses. Of the hormones tested, only insulin was strongly hepatotrophic; T3 had a minor effect, and glucagon, prolactin, angiotensin II, vasopressin, norepinephrine and estradiol were inert. Insulin-like growth factor, hepatic stimulatory substance, transforming growth factor-alpha and hepatocyte growth factor (also known as hematopoietin A) were powerfully hepatotrophic, but epidermal growth factor had a barely discernible effect. Transforming growth factor-beta was inhibitory, but tamoxifen, interleukin-1 and interleukin-2 had no effect. The hepatotrophic action of insulin was not altered when the insulin infusate was mixed with transforming growth factor-beta or tamoxifen. These experiments show the importance of in vivo in addition to in vitro testing of putative growth control factors. They illustrate how Eck's fistula model can be used to screen for such substances and possibly to help delineate their mechanisms of action.

Further steps of hepatic stimulatory substance purification

The hepatic stimulatory substance (HSS) extracted from weanling rat livers was purified 381,000-fold using chromatographic techniques including nondissociating polyacrylamide gel electrophoresis (nondenaturing PAGE). The activity of this highly purified HSS, named Acr-F4, was assessed in two in vivo models. In 40% hepatectomized rats, it produced a fivefold increase in the proliferative rate normally seen following this partial hepatectomy. In Eck fistula dogs, the level of base increase in hepatocyte renewal was amplified threefold by an infusion of Acr-F4 (50 ng/kg/day). Acr-F4 had no influence on the regenerative response of the kidney following a unilateral nephrectomy or of the bowel following a 40% resection of the small bowel. On the basis of these findings, it can be concluded that HSS (Acr-F4) has a high biological activity and is organ specific.

Hepatic stimulator substance. Discovery, characteristics and mechanism of action

Hepatic stimulator substance is a unique, 12,000- to 18,000-dalton peptide found in the liver of weanling and regenerating, but not normal, adult rats. It has also been demonstrated in dogs, rabbits, and pigs. It is organ specific, both in vivo and in vitro, but species nonspecific. It induces liver growth after a 10- to 12-hr lag period, during which time new protein and RNA synthesis are required. The initial events induced by HSS in HTC hepatoma cells in vitro include a rapid influx of Na+ via the Na+/H+ antiport and a rapid influx of extracellular Ca2+. The rise in intracellular Ca2+ appears to be dependent on the influx of Na+ and the influx of Na+ is necessary, but not in itself sufficient, to stimulate DNA synthesis.

Effect of cyclosporine on hepatic energy status and on fructose metabolism after portacaval shunt in dog as monitored by phosphorus-31 nuclear magnetic resonance spectroscopy in vivo

The effect of cyclosporin A on the hepatic energy status and intracellular pH of the liver and its response to a fructose challenge has been investigated using in vivo phosphorus-31 nuclear magnetic resonance spectroscopy in dogs. Three experimental groups were studied: (a) control dogs (n = 5), (b) dogs 4 days after the creation of an end-to-side portacaval shunt (n = 5), and (c) dogs 4 days after portacaval shunt and continuous infusion of cyclosporin A (4 mg/kg/day) by way of the left portal vein (portacaval shunt plus cyclosporin A, n = 5). The phosphorus-31 nuclear magnetic resonance spectra were obtained at 81 MHz using a Bruker BIOSPEC II 4.7-tesla nuclear magnetic resonance system equipped with a 40-cm horizontal bore superconducting solenoid. The phosphomonoesters (p less than 0.01), inorganic phosphate and ATP levels (p less than 0.05) were decreased significantly in portacaval shunt-treated and in portacaval shunt-plus-cyclosporin A-treated dogs compared with unshunted control dogs. After a fructose challenge (750 mg/kg body wt, intravenously), fructose-1-phosphate metabolism was reduced in portacaval shunt-treated dogs compared with either the normal or portacaval shunt-plus-cyclosporin A-treated dogs (p less than 0.05). Both portacaval shunt- and portacaval shunt-plus-cyclosporin A-treated dogs demonstrated a reduced decline in ATP levels after fructose infusion when compared with the controls (p less than 0.05). Immediately after the fructose challenge, the intracellular pH decreased from 7.30 +/- 0.03 to 7.00 +/- 0.05 in all animals (p less than 0.01) and then gradually returned to normal over 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatotrophic effects of FK506 in dogs

Portacaval shunt (Eck fistula) in dogs causes hepatocyte atrophy and organelle disruption, as well as tripling of hepatocyte mitoses. After submitting dogs to this procedure, FK506 was infused into the tied-off left portal vein. The size, anatomic quality, and replication of hepatocytes were enhanced in the portion of liver infused with FK506, with a significant spillover effect in the noninfused portion. These hepatotrophic qualities of FK506 may explain part of FK506's efficacy for the treatment of chronic liver rejection. Also, the observations support a trial with this drug for the treatment of autoimmune liver diseases because, in addition to turning off the immunologic genesis of such disorders, repair and regeneration of the damaged liver may be augmented. Finally, these hepatrophic qualities are part of an emerging spectrum of biologic effects caused by drugs that may modulate the enzyme cis-trans peptidyl-prolyl isomerase (PPIase), the principal constituent of the cytosolic binding sites of FK506, repatomycin, cyclosporine, and presumably other immunosuppressive drugs as yet undiscovered.

Human hepatic regenerative stimulator substance: partial purification and biological characterization of hepatic stimulator substance from human fetal liver cells

Current support or replacement therapies for fulminant acute hepatic failure are frequently very disappointing. In this study, human hepatic stimulator substance--a liver-specific growth factor--was partially purified from human fetal liver cells and characterized by its biological effects. Almost 70-fold protein content was purified with an approximately 80-fold increase in specific growth stimulator activity. Human hepatic stimulator substance proved to be heat-stable, protease-sensitive, organ-specific and species-nonspecific. Human hepatic stimulator substance produced a two- to threefold increase of 3H-thymidine incorporation into hepatic DNA when injected intraperitoneally into growing weanling mice (nonhepatectomized) or regenerating rats (34% hepatectomy). The effects of hHSS in reversing the lethality of D-galactosamine (1.6 gm/kg body weight)-induced hepatic necrosis in rats were further evaluated. A survival rate of 4% (n = 24), 41% (n = 12, p less than 0.05), 33% (n = 12, p less than 0.05), 31% (n = 13, p less than 0.05) and 18% (n = 11, p greater than 0.05) was observed when the rats were injected with 4 ml of saline intraperitoneally, 4 ml of human intact fetal hepatocytes (2.4 x 10(8] intraperitoneally, 4 ml of human hepatic stimulator substance intraperitoneally, 2 ml of twofold concentrated human hepatic stimulator substance intravenously and 1 ml of fourfold human hepatic stimulator substance intramuscularly, respectively, 20 hr after poisoning.(ABSTRACT TRUNCATED AT 250 WORDS)

The hepatotropic influence of cyclosporine

The effect of cyclosporine on liver regeneration has been investigated in 25 dogs that underwent an end-to-side portacaval shunt (Eck fistula) followed by 4 days continuous infusion of the drug into the left branch of the portal vein. Three different cyclosporine infusion rates were used: 0.06, 0.6, and 4.0 mg/kg/day. Control animals received the intravenous vehicle of cyclosporine at the same rate as the treated animals; a second control group received insulin, 0.42 units/kg/day. Hepatocyte 3H-thymidine-labeled mitoses (index of hyperplasia) and hepatocyte volume (index of hypertrophy) were studied in the left (infused) and right (control) lobes in each animal. Cyclosporine vehicle had no measurable effect on hepatocytes that suffered typical atrophy and moderate increase in mitotic index after the Eck fistula. Cyclosporine infusion stimulated cell renewal significantly and restored hepatocyte size in the infused lobes with a dose-response relation. Similar positive effects were observed in the right (nonperfused) lobes, although they were less than those in the left (infused) lobes. This was because of an unmistakable spillover of cyclosporine from the infused lobes, especially in the large-dose group. No sign of hepatotoxicity was detected at any cyclosporine infusion rate. Cyclosporine has a remarkable hepatotropic effect that may be helpful in the context of liver transplantation.

Augmentation of rat liver regeneration by FK 506 compared with cyclosporin

The immunosuppressive drug, FK 506, increased the regeneration response that follows 40% and 70% hepatectomy in rats. The effect was similar to that obtained with cyclosporin.

Clinical significance of human hepatocyte growth factor in blood from patients with fulminant hepatic failure

We have recently found the presence of human hepatocyte growth factor in sera of patients with fulminant hepatic failure and have purified human hepatocyte growth factor from plasma of a patient with fulminant hepatic failure. In this paper, we report the clinical significance of human hepatocyte growth factor in blood from patients with fulminant hepatic failure. The effect of sera or plasma from 17 patients with fulminant hepatic failure on liver cell growth was examined by use of adult rat hepatocytes in primary cultures. Sera or plasma from 16 of the 17 patients with fulminant hepatic failure stimulated DNA synthesis in hepatocytes more effectively than normal human serum. The mean growth-promoting activity for the 17 patients with fulminant hepatic failure was about 16 times higher than that obtained for normal human serum. This growth-promoting activity of the patients' blood was not related to sex, age, clinical outcome of the patients or type of fulminant hepatic failure, but was intimately related to the clinical grade of hepatic coma. Sera or plasma with Grade III and IV coma showed stimulatory activity on DNA synthesis more markedly than sera or plasma from patients with coma of less than Grade II. In the surviving group, this activity decreased as the hepatic coma of patients improved. In fact, this activity of sera from patients at the recovery stage showed no significant increase compared with that of normal human serum. In the group of terminal patients, this activity increased as the coma developed.(ABSTRACT TRUNCATED AT 250 WORDS)