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1.  mTOR signaling in liver regeneration: Rapamycin combined with growth factor treatment 
AIM: To investigate the effects of mammalian target of rapamycin (mTOR) inhibition on liver regeneration and autophagy in a surgical resection model.
METHODS: C57BL/6 mice were subjected to a 70% partial hepatectomy (PH) and treated intraperitoneally every 24 h with a combination of the mTOR inhibitor rapamycin (2.5 mg/kg per day) and the steroid dexamethasone (2.0 mg/kg per day) in phosphate buffered saline (PBS) or with PBS alone as vehicle control. In the immunosuppressant group, part of the group was treated subcutaneously 4 h prior to and 24 h after PH with a combination of human recombinant interleukin 6 (IL-6; 500 μg/kg per day) and hepatocyte growth factor (HGF; 100 μg/kg per day) in PBS. Animals were sacrificed 2, 3 or 5 d after PH and liver tissue and blood were collected for further analysis. Immunohistochemical staining for 5-Bromo-2’-deoxyuridine (BrdU) was used to quantify hepatocyte proliferation. Western blotting was used to detect hepatic microtubule-associated protein 1 light chain 3 (LC3)-II protein expression as a marker for autophagy. Hepatic gene expression levels of proliferation-, inflammation- and angiogenesis-related genes were examined by real-time reverse transcription-polymerase chain reaction and serum bilirubin and transaminase levels were analyzed at the clinical chemical core facility of the Erasmus MC-University Medical Center.
RESULTS: mTOR inhibition significantly suppressed regeneration, shown by decreased hepatocyte proliferation (2% vs 12% BrdU positive hepatocyte nuclei at day 2, P < 0.01; 0.8% vs 1.4% at day 5, P = 0.02) and liver weight reconstitution (63% vs 76% of initial total liver weight at day 3, P = 0.04), and furthermore increased serum transaminase levels (aspartate aminotransferase 641 U/L vs 185 U/L at day 2, P = 0.02). Expression of the autophagy marker LC3-II, which was reduced during normal liver regeneration, increased after mTOR inhibition (46% increase at day 2, P = 0.04). Hepatic gene expression showed an increased inflammation-related response [tumor necrosis factor (TNF)-α 3.2-fold upregulation at day 2, P = 0.03; IL-1Ra 6.0-fold upregulation at day 2 and 42.3-fold upregulation at day 5, P < 0.01] and a reduced expression of cell cycle progression and angiogenesis-related factors (HGF 40% reduction at day 2; vascular endothelial growth factor receptor 2 50% reduction at days 2 and 5; angiopoietin 1 60% reduction at day 2, all P ≤ 0.01). Treatment with the regeneration stimulating cytokine IL-6 and growth factor HGF could overcome the inhibitory effect on liver weight (75% of initial total liver weight at day 3, P = 0.02 vs immunosuppression alone and P = 0.90 vs controls) and partially reversed gene expression changes caused by rapamycin (TNF-α and IL-1Ra levels at day 2 were restored to control levels). However, no significant changes in hepatocyte proliferation, serum injury markers or autophagy were found.
CONCLUSION: mTOR inhibition severely impairs liver regeneration and increases autophagy after PH. These effects are partly reversed by stimulation of the IL-6 and HGF pathways.
PMCID: PMC3832859  PMID: 24255881
Hepatocyte proliferation; Autophagy; Microtubule-associated protein 1 light chain 3; Partial hepatectomy; Rapamycin
2.  Quantification of Viral DNA and Liver Enzymes in Plasma Improves Early Diagnosis and Management of Herpes Simplex Virus Hepatitis 
Journal of viral hepatitis  2010;18(4):e160-e166.
Herpes simplex virus (HSV) hepatitis is a rare and potential life-threatening disease. The diagnosis of HSV hepatitis is hampered by its indifferent clinical presentation, which necessitates confirmatory laboratory data to identify HSV in the affected liver. However, liver biopsies are often contraindicated in the context of coagulopathy, are prone to sampling errors and have low sensitivity in mild HSV hepatitis cases. There is an unmet need for less-invasive diagnostic tools.
The diagnostic and therapeutic value of HSV DNA load and liver enzyme level kinetics was determined in five HSV hepatitis patients and twenty disease controls with HSV-DNAemia without hepatitis.
At time of hospitalization, HSV hepatitis patients had a higher median (± interquartile range) HSV DNA load (6.0×106 ± 1.2×109) compared to disease controls (171 ± 2,845). Viral DNA load correlated with liver transaminase levels and disease severity. Antiviral treatment led to rapid decline of HSV DNA load and improvement of liver function of HSV hepatitis patients.
The data advocate the prompt and consecutive quantification of the HSV DNA load and liver enzyme levels in plasma of patients suspected of HSV hepatitis as well as those under antiviral treatment.
PMCID: PMC2992574  PMID: 20704650
Acute Liver Failure; Herpes simplex virus; Plasma Viral Load; Diagnosis; Follow-up
3.  Detailed Kinetics of the Direct Allo-Response in Human Liver Transplant Recipients: New Insights from an Optimized Assay 
PLoS ONE  2010;5(12):e14452.
Conventional assays for quantification of allo-reactive T-cell precursor frequencies (PF) are relatively insensitive. We present a robust assay for quantification of PF of T-cells with direct donor-specificity, and establish the kinetics of circulating donor-specific T cells after liver transplantation (LTx). B cells from donor splenocytes were differentiated into professional antigen-presenting cells by CD40-engagement (CD40-B cells). CFSE-labelled PBMC from LTx-recipients obtained before and at several time points after LTx, were stimulated with donor-derived or 3rd party CD40-B cells. PF of donor-specific T cells were calculated from CFSE-dilution patterns, and intracellular IFN-γ was determined after re-stimulation with CD40-B cells. Compared to splenocytes, stimulations with CD40-B cells resulted in 3 to 5-fold higher responding T-cell PF. Memory and naïve T-cell subsets responded equally to allogeneic CD40-B cell stimulation. Donor-specific CD4+ and CD8+ T-cell PF ranged from 0.5 to 19% (median: 5.2%). One week after LTx, PF of circulating donor-specific CD4+ and CD8+ T cells increased significantly, while only a minor increase in numbers of T cells reacting to 3rd party allo-antigens was observed. One year after LTx numbers of CD4+ and CD8+ T cells reacting to donor antigens, as well as those reacting to 3rd party allo-antigens, were slightly lower compared to pre-transplant values. Moreover, CD4+ and CD8+ T cells responding to donor-derived, as well as those reacting to 3rd party CD40-B cells, produced less IFN-γ. In conclusion, our alternative approach enables detection of allo-reactive human T cells at high frequencies, and after application we conclude that donor-specific T-cell PF increase immediately after LTx. However, no evidence for a specific loss of circulating T-cells recognizing donor allo-antigens via the direct pathway up to 1 year after LTx was obtained, underscoring the relative insensitiveness of previous assays.
PMCID: PMC3012075  PMID: 21206923
4.  Trends in liver transplantation for primary biliary cirrhosis in the Netherlands 1988-2008 
BMC Gastroenterology  2010;10:144.
A decrease in the need for liver transplantations (LTX) in Primary Biliary Cirrhosis (PBC), possibly related to treatment with ursodeoxycholic acid (UDCA), has been reported in the USA and UK. The aim of this study was to assess LTX requirements in PBC over the past 20 years in the Netherlands.
Analysis of PBC transplant data of the Dutch Organ Transplant Registry during the period 1988-2008, including both absolute and proportional numbers. The indication for LTX was categorized as liver failure, hepatocellular carcinoma or poor quality of life (severe fatigue or pruritus). Data were analysed for two decades: 1.1.1988-31.12.1997 (1st) and 1.1.1998-31.12.2007 (2nd). The severity of disease was quantified using MELD scores. To fit lines which show trends over time we applied a linear regression model.
A total of 110 patients (87% women) was placed on the waiting list. 105 patients were transplanted (1st: 61, 2nd: 44), 5 (5%) died while listed. The absolute annual number of LTX for PBC slightly decreased during the 20 year period, the proportional number decreased significantly. At the time of LTX the mean age was 53.6 yrs. (1st: 53.4, 2nd: 53.8), the mean MELD score 13.9 (1st:14.5, 2nd:13.0). The median interval from diagnosis to LTX was 90.5 months (1st:86.5, 2nd: 93.5). 69% of patients was treated with UDCA (1st 38%, 2nd 82%).
Over the past 20 years the absolute number of LTX for PBC in the Netherlands showed a tendency to decrease whereas the proportional decrease was significant. There was a trend over time toward earlier transplantation.
PMCID: PMC3020176  PMID: 21172005
5.  Combined antiviral activity of interferon-α and RNA interference directed against hepatitis C without affecting vector delivery and gene silencing 
The current standard interferon-alpha (IFN-α)-based therapy for chronic hepatitis C virus (HCV) infection is only effective in approximately half of the patients, prompting the need for alternative treatments. RNA interference (RNAi) represents novel approach to combat HCV by sequence-specific targeting of viral or host factors involved in infection. Monotherapy of RNAi, however, may lead to therapeutic resistance by mutational escape of the virus. Here, we proposed that combining lentiviral vector-mediated RNAi and IFN-α could be more effective and avoid therapeutic resistance. In this study, we found that IFN-α treatment did not interfere with RNAi-mediated gene silencing. RNAi and IFN-α act independently on HCV replication showing combined antiviral activity when used simultaneously or sequentially. Transduction of mouse hepatocytes in vivo and in vitro was not effected by IFN-α treatment. In conclusion, RNAi and IFN-α can be effectively combined without cross-interference and may represent a promising combinational strategy for the treatment of hepatitis C.
PMCID: PMC2700866  PMID: 19404587
RNAi; IFN-α; Gene therapy; Lentiviral vector; HCV
6.  Physical fitness, fatigue, and quality of life after liver transplantation 
Fatigue is often experienced after liver transplantation. The aims of this cross-sectional study were to assess physical fitness (cardiorespiratory fitness, neuromuscular fitness, body composition) in liver transplant recipients and to explore whether physical fitness is related to severity of fatigue. In addition, we explored the relationship between physical fitness and health-related quality of life. Included were 18 patients 1–5 years after transplantation (aged 48.0 ± 11.8 years) with varying severity of fatigue. Peak oxygen uptake during cycle ergometry, 6-min walk distance, isokinetic muscle strength of the knee extensors, body mass index, waist circumference, skinfold thickness, severity of fatigue, and health-related quality of life were measured. Cardiorespiratory fitness in the liver transplant recipients was on average 16–34% lower than normative values (P ≤ 0.05). Furthermore, the prevalence of obesity seemed to be higher than in the general population (17 vs. 10%). We found no deficit in neuromuscular fitness. Cardiorespiratory fitness was the only fitness component that was related with severity of fatigue (rs = −0.61 to rs = -0.50, P ≤ 0.05). Particularly cardiorespiratory fitness was related with several aspects of health-related quality of life (rs = 0.48 to rs = 0.70, P ≤ 0.05). Results of our study imply that cardiorespiratory fitness and body composition are impaired in liver transplant recipients and that fitness is related with severity of fatigue (only cardiorespiratory fitness) and quality of life (particularly cardiorespiratory fitness) in this group. These findings have implications for the development of rehabilitation programs for liver transplant recipients.
PMCID: PMC1914221  PMID: 17364193
Liver transplantation; Fatigue; Peak oxygen uptake; Isokinetic muscle strength; Body composition

Results 1-6 (6)