Modulation of the hepatic RANK-RANKL-OPG axis by combined C5 and CD14 inhibition in a long-term polytrauma model

Frontiers in Immunology, vol. 15, pp. 1434274

Abstract

Background: Polytrauma and hemorrhagic shock can lead to direct and indirect liver damage involving intricate pathophysiologic mechanisms. While hepatic function has been frequently highlighted, there is minimal research on how the receptor activator of the NF-κB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system is regulated in the liver following trauma. Furthermore, cross-talking complement and toll-like-receptor (TLR) systems can contribute to the posttraumatic response. Therefore, we investigated the hepatic consequences of polytrauma focusing on the RANK-RANKL-OPG axis, and evaluated the effects of a dual blockade of complement factor C5 and TLR-cofactor CD14 on hepatic features. Methods: The established pig model of polytrauma (PT) and hemorrhagic shock included pulmonary contusion, hepatic dissection, and bilateral femur fractures, surgically addressed either by external fixation (Fix ex) or intramedullary nailing (Nail). Four groups were investigated: 1) sham animals; 2) PT treated by Fix ex (Fix ex); 3) PT by Nail (Nail); or 4) PT by Nail plus combined C5/CD14 inhibition (Nail+Therapy). Serum samples were obtained between 0 - 72 h, and liver samples at 72 h after PT. Liver tissues were histologically scored and subjected to RT-qPCR-analyses, immunohistochemistry and ELISAs to evaluate the posttraumatic hepatic response with a focus on the RANK-RANKL-OPG system. Results: Following PT, the liver injury score of the Nail+Therapy group was significantly lower than in the Fix ex or Nail group without immunomodulation (p<0.05). Similarly, the degree of necrosis, lobular stasis, and inflammation were significantly reduced when treated with C5/CD14-inhibitors. Compared to the Nail group, AST serum concentrations were significantly decreased in the Nail+Therapy group after 72 h (p<0.05). PCR analyses indicated that RANK, RANKL, and OPG levels in the liver were increased after PT in the Nail group compared to lower levels in the Nail+Therapy group. Furthermore, liver tissue analyses revealed increased RANK protein levels and cellular immunostaining for RANK in the Nail group, both of which were significantly reduced in the case of C5/CD14-inhibition (p<0.05). Conclusion: Following experimental PT, dual inhibition of C5/CD14 resulted in altered, mainly reduced hepatic synthesis of proteins relevant to bone repair. However, a comprehensive investigation of the subsequent effects on the liver-bone axis are needed.

Authors 17

1. Yang Li

   Universität Ulm · University Hospital Ulm

   Affiliation as printed

   Institute of Clinical and Experimental Trauma Immunology, Ulm University Medical Center, Ulm, Germany

2. Klemens Horst Aachen Department of Orthopaedics, Trauma and Reconstructive Surgery

   RWTH Aachen University

   Affiliation as printed

   Department of Orthopaedics, Trauma and Reconstructive Surgery, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany

3. Johannes Greven Aachen Department of Orthopaedics, Trauma and Reconstructive Surgery

   RWTH Aachen University

   Affiliation as printed

   Department of Orthopaedics, Trauma and Reconstructive Surgery, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany

4. Ümit Mert Aachen Department of Orthopaedics, Trauma and Reconstructive Surgery

   RWTH Aachen University

   Affiliation as printed

   Department of Orthopaedics, Trauma and Reconstructive Surgery, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany

5. Ludmila Lupu

   Universität Ulm · University Hospital Ulm

   Affiliation as printed

   Institute of Clinical and Experimental Trauma Immunology, Ulm University Medical Center, Ulm, Germany

6. Annette Palmer

   Universität Ulm · University Hospital Ulm

   Affiliation as printed

   Institute of Clinical and Experimental Trauma Immunology, Ulm University Medical Center, Ulm, Germany

7. Lena Doerfer

   Universität Ulm · University Hospital Ulm

   Affiliation as printed

   Institute of Clinical and Experimental Trauma Immunology, Ulm University Medical Center, Ulm, Germany

8. Qun Zhao Aachen Department of Orthopaedics, Trauma and Reconstructive Surgery

   RWTH Aachen University

   Affiliation as printed

   Department of Orthopaedics, Trauma and Reconstructive Surgery, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany

9. Xing Zhang Aachen Department of Orthopaedics, Trauma and Reconstructive Surgery

   RWTH Aachen University

   Affiliation as printed

   Department of Orthopaedics, Trauma and Reconstructive Surgery, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany

10. Rebecca Halbgebauer

    Universität Ulm · University Hospital Ulm

    Affiliation as printed

    Institute of Clinical and Experimental Trauma Immunology, Ulm University Medical Center, Ulm, Germany

11. Anita A. Ignatius

    Universität Ulm · University Hospital Ulm

    Affiliation as printed

    Institute of Orthopaedic Research and Biomechanics, Ulm University Medical Center, Ulm, Germany

12. İngo Marzi

    University Hospital Frankfurt · Goethe University Frankfurt

    Affiliation as printed

    Department of Trauma, Hand, and Reconstructive Surgery, University Hospital Frankfurt, Goethe University, Frankfurt/Main, Germany

13. Martijn van Griensven

    Maastricht University

    Affiliation as printed

    The Department of Cell Biology-Inspired Tissue Engineering (cBITE), MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, Netherlands

14. Elizabeth Rosado Balmayor Aachen Department of Orthopaedics, Trauma and Reconstructive Surgery

    RWTH Aachen University

    Affiliation as printed

    Department of Orthopaedics, Trauma and Reconstructive Surgery, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany

15. Frank Hildebrand Aachen Department of Orthopaedics, Trauma and Reconstructive Surgery

    RWTH Aachen University

    Affiliation as printed

    Department of Orthopaedics, Trauma and Reconstructive Surgery, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Aachen, Germany

16. Tom Eirik Mollnes

    University of Oslo · Oslo University Hospital · Nordland Hospital Trust · Nordland Hospital

    Affiliation as printed

    Department of Immunology, Oslo University Hospital, University of Oslo, Oslo, Norway

    Research Laboratory, Nordland Hospital Bodø, Bodø, Norway

17. Markus Stefan Huber-Lang

    Universität Ulm · University Hospital Ulm

    Affiliation as printed

    Institute of Clinical and Experimental Trauma Immunology, Ulm University Medical Center, Ulm, Germany