Investigating the role of the stem cell homing pathway in acute-on-chronic liver failure should be enough for a title.
Final Report Abstract
Acute-on-chronic liver failure (ACLF) occurs in cirrhotic patients and is characterised clinically by multiorgan failure, and pathophysiologically by systemic inflammation and failure of hepatic regeneration. Inhibition of tolllike receptor 4 (TLR4) reduced inflammation and improved survival of models of ACLF but abrogated regeneration. Granulocyte colony stimulating factor (G-CSF) acts by mobilising stems cells but did not improve survival of patients with ACLF. This study was performed to explore whether combining G-CSF with TLR4 antagonist would reduce inflammation whilst enhancing liver regeneration resulting in improved outcomes in models of ACLF. Two mouse models of ACLF were investigated. Chronic liver injury was induced by CCl4 (0.5mg/ml) gavage for 6-weeks followed by either Lipopolysaccharide (LPS, Klebsiella pneumoniae, 4mg/kg) or Galactosamine (GalN,1000mg/kg) i.p. injections acting as extrahepatic and hepatic second insults, respectively. Thereafter (1h), G-CSF (250µg s.c.) and/or TLR4-inhibitor, TAK-242 (10mg/kg i.p.), were injected and continued once every 24h. The treatment duration was 24h and 5d in the LPS model and 48h in the GalN model, respectively. Samples were stored and analyzed later. Induction of ACLF with 6-weeks of CCl4 and acute LPS combined with G-CSF treatment was associated with high rates of mortality (Placebo: 0%; G-CSF: 66%) due to worsening liver injury, increased macrophage infiltration, stellate cell activation and hepatic inflammation. The addition of TAK-242 to G-CSF abrogated mortality (0%) and significantly reduced both liver injury, macrophage infiltration and inflammation. GalN injection on the background of CCl4 also induced significant liver injury but both G-CSF and TAK-242, when used individually reduced liver injury; their combination (G-CSF+TAK-242) was significantly more effective in this model. G-CSF treatment, with or without TAK-242, was associated with activation of the pro-regenerative and anti-apoptotic STAT3 pathway, evidenced by increased pSTAT3 and BCL2 liver expression. LPS-driven ACLF was characterized by induction of hepatocyte senescence (p21 overexpression) and inhibition of proliferation (Cyclin A2, Ki67 negative). While TAK-242 treatment was able to mitigate the effect on senescence, G-CSF therapy, when administered over 5-days with TAK-242, resulted in a significant increase of proliferating hepatocytes (Cyclin A2 and Ki67 positive). G-CSF administration had mixed results in ACLF patients with some studies showing usefulness whilst others showing lack of effect and even highlighted potential harm. The present study clearly showed the deleterious effect of G-CSF in the context of LPS-driven ACLF. TLR4 inhibition with TAK-242 rescued G-CSF-driven cell death, inflammation, enhanced tissue repair and significantly induced regeneration. Therefore, the synergistic action of G-CSF and TAK-242 may be used to improve the outcome of ACLF patients. These results were the basis for a proposed clinical phase 2 trial in patients with severe alcoholc hepatitis and ACLF which was submitted to H2020.
Publications
- Loss of paraspinal muscle mass is a gender-specific consequence of cirrhosis that predicts complications and death. Aliment Pharmacol Ther 2018;48(11-12):1271-1281
Engelmann C et al.
(See online at https://doi.org/10.1111/apt.15026) - Validation of CLIF-C ACLF score to define a threshold for futility of intensive care support for patients with acute-on-chronic liver failure. Crit Care 2018;22(1):254
Engelmann C et al.
(See online at https://doi.org/10.1186/s13054-018-2156-0) - Recombinant alkaline phosphatase prevents acute-on-chronic liver failure. Sci Rep 2020;10(1):389
Engelmann C et al.
(See online at https://doi.org/10.1038/s41598-019-57284-z) - Toll-like receptor 4 is a therapeutic target fort he prevention and treatment of liver failure. J Hepatol 2020;72(1):102-112
Engelmann C et al.
(See online at https://doi.org/10.1016/j.jhep.2020.01.011)
