Hepatocyte proliferation and serum hepatocyte growth factor levels in patients with alcoholic hepatitis

Autologous bone marrow mononuclear cell transplantation in patients with decompensated alcoholic liver disease: a randomized controlled trial

Objective

Impaired liver regeneration is associated with a poor outcome in patients with decompensated alcoholic liver disease (ALD). We assessed whether autologous bone marrow mononuclear cell transplantation (BMMCT) improved liver function in decompensated ALD.

Design

58 patients (mean age 54 yrs; mean MELD score 19, all with cirrhosis, 81% with alcoholic steatohepatitis at baseline liver biopsy) were randomized early after hospital admission to standard medical therapy (SMT) alone (n = 30), including steroids in patients with a Maddrey’s score ≥32, or combined with G-CSF injections and autologous BMMCT into the hepatic artery (n = 28). Bone marrow cells were harvested, isolated and reinfused the same day. The primary endpoint was a ≥3 points decrease in the MELD score at 3 months, corresponding to a clinically relevant improvement in liver function. Liver biopsy was repeated at week 4 to assess changes in Ki67+/CK7+ hepatic progenitor cells (HPC) compartment.

Results

Both study groups were comparable at baseline. After 3 months, 2 and 4 patients died in the BMMCT and SMT groups, respectively. Adverse events were equally distributed between groups. Moderate alcohol relapse occurred in 31% of patients. The MELD score improved in parallel in both groups during follow-up with 18 patients (64%) from the BMMCT group and 18 patients (53%) from the SMT group reaching the primary endpoint (p = 0.43 (OR 1.6, CI 0.49–5.4) in an intention to treat analysis. Comparing liver biopsy at 4 weeks to baseline, steatosis improved (p<0.001), and proliferating HPC tended to decrease in both groups (−35 and −33%, respectively).

Conclusion

Autologous BMMCT, compared to SMT is a safe procedure but did not result in an expanded HPC compartment or improved liver function. These data suggest either insufficient regenerative stimulation after BMMCT or resistance to liver regenerative drive in patients with decompensated alcoholic cirrhosis.

Trial Registration

Controlled-Trials.com ISRCTN83972743.

Molecular targets in the treatment of alcoholic hepatitis

Alcohol related costs to health and society are high. One of the most serious complications of alcohol misuse to the individual is the development of alcoholic hepatitis (AH), a clinical syndrome of jaundice and progressive inflammatory liver injury in patients with a history of recent heavy alcohol use. It has a poor outcome and few existing successful therapies. The use of glucocorticoids in patients with severe AH is still controversial and there remains a group of patients with glucocorticoid-resistant disease. However, as our understanding of the pathogenesis of the condition improves there are opportunities to develop new targeted therapies with specific actions to control liver inflammation without having a detrimental effect on the immune system as a whole. In this article we review the molecular mechanisms of AH concentrating on the activation of the innate and adaptive immune response. We consider existing treatments including glucocorticoids, anti-tumor necrosis factor therapy and pentoxifylline and their limitations. Using our knowledge of the disease pathogenesis we discuss possible novel therapeutic approaches. New targets include pro-inflammatory cytokines such as interleukin (IL)-17, chemokines and their receptors (for example IL-8, CXCL9 and CXCR3) and augmentation of anti-inflammatory molecules such as IL-10 and IL-22. And there is also future potential to consider combination therapy to selectively modulate the immune response and gain control of disease.

Increased level of hepatocyte growth factor in children with dengue virus infection

BACKGROUND

Evidence of hepatocellular damage is common in dengue-infected individuals. Hepatocyte growth factor (HGF), a key cytokine responsible for liver regeneration, may play a prognostic role in dengue virus infection.

AIM

To determine the relationship between serum HGF level and disease severity in patients with dengue virus infection.

METHODS

Serum samples from 27 children [17 dengue fever (DF), ten dengue haemorrhagic fever (DHF)] with serologically confirmed dengue virus infection during the febrile, toxic stages and at follow-up were analysed for HGF. Serum samples obtained from nine healthy children served as the control group.

RESULTS

In dengue-infected patients, serum HGF was significantly higher at the febrile and toxic stages than at follow-up (p<0.05). In comparison with DF, patients with DHF had a greater level of HGF at the febrile stage (p<0.05). A cut-off HGF level of 1220 pg/mL obtained during the febrile stage showed a sensitivity of 90% and a specificity of 53% for predicting clinical progression to DHF (area under the ROC curve 0.75).

CONCLUSION

Serum HGF level at the early stage of dengue virus infection is elevated and may be a useful predictor for clinical progression to DHF.

Treatment of alcoholic hepatitis

Cirrhosis and its sequelae are responsible for close to 2% of all causes of death in the United States. Some studies have suggested that the costs of liver disease may account for as much as 1% of all health care spending, with alcohol-related liver disease (ALD) representing a major portion. It accounts for between 40% to 50% of all deaths due to cirrhosis, with an accompanying rate of progression of up to 60% in patients with pure alcoholic fatty liver over 10 years, and a 5-year survival rate as low as 35% if patients continue to drink. A subset of patients with ALD will develop an acute, virulent form of injury, acute alcoholic hepatitis, which has a substantially worse prognosis. Despite enormous progress in understanding the physiology of this disease, much remains unknown, and therefore, a consensus regarding effective therapy for ALD is lacking. Conventional therapy is still based largely on abstinence from alcohol, as well as general supportive and symptomatic care. Unfortunately, hepatocellular damage may progress despite these measures. Multiple treatment interventions for both the short- and long-term morbidity and mortality of this disease have been proposed, but strong disagreement exists among experts regarding the value of any of the proposed specific therapeutic interventions.

Hepatocyte growth factor: from diagnosis to clinical applications

Hepatocyte growth factor (HGF), initially identified and molecularly cloned as a potent mitogen of primary cultured hepatocytes, has multiple activities in a variety of tissues during the course of development and also in various disease states. HGF plays key roles in the attenuation of disease progression as an intrinsic repair factor. It is also evident that HGF levels are regulated under different conditions, for example, during the course of pregnancy, aging, and disease. This review focuses on the levels of HGF in normal and pathophysiological situations and examines the relationships between HGF levels and disease, disease stage, and disease prognosis. The clinical potential of HGF as a treatment for subjects with various diseases is also given attention.

Liver regeneration investigated in a non-human primate model (Macaca mulatta)

BACKGROUND/AIMS

An adequate model to study liver regeneration in humans is presently unavailable. We explored the feasibility of studying liver regeneration in a genetically similar species to man, the non-human primate Rhesus macaque.

METHODS

Five animals were studied; two underwent 60% hepatectomy, one underwent 30% hepatectomy, and cholecystectomy alone was performed on two animals. Laparoscopic-guided or open liver biopsies were performed on days 1, 2, 7, 14, 21, 30 and 60 following all surgeries. Liver regeneration was evaluated by measuring Ki-67, proliferating cell nuclear antigen expression and mitotic index, calculating changes in the surface area of the liver remnant and assessing intrahepatic production of cytokines.

RESULTS

Significant liver regeneration was induced in the animals that underwent 60% hepatectomy, peaking between days 21-30 postoperatively. Regeneration was minimal in all other animals studied. Cytokine production followed a similar pattern. Maximal liver regeneration correlated with restoration of surface area in the liver remnant.

CONCLUSIONS

Sixty percent hepatectomy in a non-human primate model induced significant liver regeneration, maximizing 21-30 days following partial hepatectomy, suggesting a significant interspecies difference when compared to a rodent hepatectomy model. A partial hepatectomy model in Rhesus macaques may allow further characterization of liver regeneration in a species closer to humans.

Polymorphonuclear neutrophils are a source of hepatocyte growth factor in patients with severe alcoholic hepatitis

BACKGROUND/AIMS

Hepatocyte growth factor (HGF) is a pleiotropic cytokine involved in liver regeneration. Plasma HGF levels correlate with survival and hepatocyte proliferation in alcoholic hepatitis (AH). As AH is accompanied by inflammation, neutrophilia and polymorphonuclear neutrophil (PMN) infiltration of the liver, we postulated that PMN could be a source of HGF in such patients.

METHODS

We studied 25 patients with severe AH in comparison with 20 alcoholic cirrhotic patients without AH and 20 healthy controls; the impact of a 28-day course of corticosteroids was evaluated in patients with AH.

RESULTS

On day 0, HGF plasma and homogenized liver tissue levels were markedly increased in AH patients as compared to controls. The role of PMN in HGF production during AH was confirmed by a significantly higher ex-vivo HGF production capacity of lipopolysaccharide-stimulated blood PMN from AH patients relative to both control groups. Formyl-Methionyl-Leucyl-Phenylalanine-induced PMN release of HGF (degranulation conditions) was also higher in AH patients. In this setting, we found that HGF release by PMN ex vivo correlated strongly with HGF plasma levels, and that the degree of hepatic PMN correlated strongly with hepatic HGF levels. HGF plasma levels and ex-vivo HGF release by PMN were unaffected by steroid therapy.

CONCLUSIONS

These findings suggest that, by releasing HGF, PMN could participate in liver regeneration during severe alcoholic hepatitis.

Induction of DNA synthesis in mouse liver following increases of DNA adduct levels elicited by very low cumulative doses of the genotoxic hepatocarcinogen 7H-dibenzo[c,g]carbazole

The purpose of this work was to investigate the administration of very low but repeated doses of a genotoxic carcinogen and an eventual correlation with cellular DNA synthesis. The compound 7H-dibenzo[c,g]carbazole is a genotoxic carcinogen in the mouse liver and was administered topically at the dose of 13.35 microg per animal every 2 days to give a total of 13 applications. Animals were sacrificed 48 hours after every 2 applications until the 10th treatment, then 48 hours after every treatment. Postulated genotoxic effects such as DNA adduct formation were detected by the 32P-post labeling assay. Liver sections were examined for microscopic changes and DNA synthesis. Results showed an increase of the total DNA adduct level in the liver throughout the study with a slowing down in the level after the sixth application of the compound. This change could correspond to the onset of DNA synthesis and to the moderate hepatocellular apoptosis which was observed. The DNA synthesis, which was considered to be secondary to the cytotoxicity induced by the high level of DNA adducts altering normal cellular activity, could also be the opportunity to fix the DNA adducts into heritable mutations. These results raise the question regarding the risk assessment in humans exposed regularly to very low doses of chemicals in the environment: for non-proliferating tissue, the regular accumulation of DNA adducts could remain silent until a "threshold level" is reached from which stimulation of the DNA synthesis may fix the DNA adducts into heritable mutations, eventually leading to tumors.

Alcohol and cytokine networks

Experimental and clinical data pertaining to alcohol (ethanol, EtOH) interference with cytokine networks are analyzed from the viewpoint of their importance for understanding the deleterious effects of EtOH on various functions. The data are grouped and analysed according to several major directions that have emerged in the last decade since the research on EtOH interference with cytokine networks started. These are: cytokine secretion, including the effects of the drug on in vivo cytokine levels and on in vitro cytokine secretion by various cells; cytokine-receptor interaction; intracellular fate of cytokines; and cellular responses to cytokines. Correspondingly, the data are presented in four tables. Attention is paid to the fact that the effects of EtOH on various aspects of cytokine biology (e.g., secretion by various cells) are diversified. Contradictory data have been reported but the cause for discrepancy is poorly understood. EtOH effects vary with the cytokine studied, the method of EtOH administration (i.e., acute or chronic), the species used, or with other experimental conditions. It is important to note, however, that the vast majority of experimental and clinical data show that EtOH interferes with cytokine networks and that research on such interference may lead to important steps in understanding the mechanisms of action of EtOH. An attempt is made herein to select aspects of cytokine biology, as affected by EtOH, that have been studied to a lesser extent, thus calling for more research efforts in those areas.