1. Immunological Aspects of AXL/GAS-6 in the Context of Human Liver Regeneration.
- Author
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Ortmayr G, Brunnthaler L, Pereyra D, Huber H, Santol J, Rumpf B, Najarnia S, Smoot R, Ammon D, Sorz T, Fritsch F, Schodl M, Voill-Glaninger A, Weitmayr B, Födinger M, Klimpfinger M, Gruenberger T, Assinger A, Mikulits W, and Starlinger P
- Subjects
- Biomarkers, Humans, Inflammation, Interleukin-6, Signal Transduction, Axl Receptor Tyrosine Kinase, Intercellular Signaling Peptides and Proteins immunology, Liver Regeneration, Proto-Oncogene Proteins immunology, Receptor Protein-Tyrosine Kinases immunology
- Abstract
AXL and its corresponding ligand growth arrest-specific 6 (GAS-6) are critically involved in hepatic immunomodulation and regenerative processes. Pleiotropic inhibitory effects on innate inflammatory responses might essentially involve the shift of macrophage phenotype from a pro-inflammatory M1 to an anti-inflammatory M2. We aimed to assess the relevance of the AXL/GAS-6-pathway in human liver regeneration and, consequently, its association with clinical outcome after hepatic resection. Soluble AXL (sAXL) and GAS-6 levels were analyzed at preoperative and postoperative stages in 154 patients undergoing partial hepatectomy and correlated with clinical outcome. Perioperative dynamics of interleukin (IL)-6, soluble tyrosine-protein kinase MER (sMerTK), soluble CD163 (sCD163), and cytokeratin (CK) 18 were assessed to reflect pathophysiological processes. Preoperatively elevated sAXL and GAS-6 levels predicted postoperative liver dysfunction (area under the curve = 0.721 and 0.722; P < 0.005) and worse clinical outcome. These patients failed to respond with an immediate increase of sAXL and GAS-6 upon induction of liver regeneration. Abolished AXL pathway response resulted in a restricted increase of sCD163, suggesting a disrupted phenotypical switch to regeneratory M2 macrophages. No association with sMerTK was observed. Concomitantly, a distinct association of IL-6 levels with an absent increase of AXL/GAS-6 signaling indicated pronounced postoperative inflammation. This was further supported by increased intrahepatic secondary necrosis as reflected by CK18M65. sAXL and GAS-6 represent not only potent and easily accessible preoperative biomarkers for the postoperative outcome but also AXL/GAS-6 signaling might be of critical relevance in human liver regeneration. Refractory AXL/GAS-6 signaling, due to chronic overactivation/stimulation in the context of underlying liver disease, appears to abolish their immediate release following induction of liver regeneration, causing overwhelming immune activation, presumably via intrahepatic immune regulation., (© 2021 The Authors. Hepatology Communications published by Wiley Periodicals LLC on behalf of American Association for the Study of Liver Diseases.)
- Published
- 2022
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