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Kengelbach-Weigand A, Thielen C, Bäuerle T, Götzl R, Gerber T, Körner C, Beier JP, Horch RE, Boos AM. Personalized medicine for reconstruction of critical-size bone defects - a translational approach with customizable vascularized bone tissue. NPJ Regen Med 2021; 6:49. [PMID: 34413320 PMCID: PMC8377075 DOI: 10.1038/s41536-021-00158-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 07/29/2021] [Indexed: 02/07/2023] Open
Abstract
Tissue engineering principles allow the generation of functional tissues for biomedical applications. Reconstruction of large-scale bone defects with tissue-engineered bone has still not entered the clinical routine. In the present study, a bone substitute in combination with mesenchymal stem cells (MSC) and endothelial progenitor cells (EPC) with or without growth factors BMP-2 and VEGF-A was prevascularized by an arteriovenous (AV) loop and transplanted into a critical-size tibia defect in the sheep model. With 3D imaging and immunohistochemistry, we could show that this approach is a feasible and simple alternative to the current clinical therapeutic option. This study serves as proof of concept for using large-scale transplantable, vascularized, and customizable bone, generated in a living organism for the reconstruction of load-bearing bone defects, individually tailored to the patient's needs. With this approach in personalized medicine for the reconstruction of critical-size bone defects, regeneration of parts of the human body will become possible in the near future.
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Affiliation(s)
- Annika Kengelbach-Weigand
- grid.411668.c0000 0000 9935 6525Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Carolina Thielen
- grid.411668.c0000 0000 9935 6525Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Tobias Bäuerle
- grid.5330.50000 0001 2107 3311Institute of Radiology, Preclinical Imaging Platform Erlangen (PIPE), University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Rebekka Götzl
- grid.411668.c0000 0000 9935 6525Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany ,grid.412301.50000 0000 8653 1507Present Address: Department of Plastic Surgery, Hand Surgery, Burn Center, University Hospital RWTH Aachen, Aachen, Germany
| | - Thomas Gerber
- grid.10493.3f0000000121858338Institute of Physics, University of Rostock, Rostock, Germany
| | - Carolin Körner
- grid.5330.50000 0001 2107 3311Department of Materials Science and Engineering, Institute of Science and Technology of Metals, Friedrich-Alexander-University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Justus P. Beier
- grid.411668.c0000 0000 9935 6525Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany ,grid.412301.50000 0000 8653 1507Present Address: Department of Plastic Surgery, Hand Surgery, Burn Center, University Hospital RWTH Aachen, Aachen, Germany
| | - Raymund E. Horch
- grid.411668.c0000 0000 9935 6525Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Anja M. Boos
- grid.411668.c0000 0000 9935 6525Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany ,grid.412301.50000 0000 8653 1507Present Address: Department of Plastic Surgery, Hand Surgery, Burn Center, University Hospital RWTH Aachen, Aachen, Germany
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2
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Mende W, Götzl R, Kubo Y, Pufe T, Ruhl T, Beier JP. The Role of Adipose Stem Cells in Bone Regeneration and Bone Tissue Engineering. Cells 2021; 10:cells10050975. [PMID: 33919377 PMCID: PMC8143357 DOI: 10.3390/cells10050975] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 02/07/2023] Open
Abstract
Bone regeneration is a complex process that is influenced by tissue interactions, inflammatory responses, and progenitor cells. Diseases, lifestyle, or multiple trauma can disturb fracture healing, which might result in prolonged healing duration or even failure. The current gold standard therapy in these cases are bone grafts. However, they are associated with several disadvantages, e.g., donor site morbidity and availability of appropriate material. Bone tissue engineering has been proposed as a promising alternative. The success of bone-tissue engineering depends on the administered cells, osteogenic differentiation, and secretome. Different stem cell types offer advantages and drawbacks in this field, while adipose-derived stem or stromal cells (ASCs) are in particular promising. They show high osteogenic potential, osteoinductive ability, and immunomodulation properties. Furthermore, they can be harvested through a noninvasive process in high numbers. ASCs can be induced into osteogenic lineage through bioactive molecules, i.e., growth factors and cytokines. Moreover, their secretome, in particular extracellular vesicles, has been linked to fracture healing. The aim of this review is a comprehensive overview of ASCs for bone regeneration and bone tissue engineering.
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Affiliation(s)
- Wolfgang Mende
- Hand Surgery-Burn Center, Department of Plastic Surgery, RWTH Aachen University Hospital, 52074 Aachen, Germany
| | - Rebekka Götzl
- Hand Surgery-Burn Center, Department of Plastic Surgery, RWTH Aachen University Hospital, 52074 Aachen, Germany
| | - Yusuke Kubo
- Department of Anatomy and Cell Biology, RWTH Aachen University Hospital, 52074 Aachen, Germany
| | - Thomas Pufe
- Department of Anatomy and Cell Biology, RWTH Aachen University Hospital, 52074 Aachen, Germany
| | - Tim Ruhl
- Hand Surgery-Burn Center, Department of Plastic Surgery, RWTH Aachen University Hospital, 52074 Aachen, Germany
| | - Justus P Beier
- Hand Surgery-Burn Center, Department of Plastic Surgery, RWTH Aachen University Hospital, 52074 Aachen, Germany
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Maurel DB, Fénelon M, Aid-Launais R, Bidault L, Le Nir A, Renard M, Fricain JC, Letourneur D, Amédée J, Catros S. Bone regeneration in both small and large preclinical bone defect models using an injectable polymer-based substitute containing hydroxyapatite and reconstituted with saline or autologous blood. J Biomed Mater Res A 2021; 109:1840-1848. [PMID: 33797182 DOI: 10.1002/jbm.a.37176] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 03/18/2021] [Accepted: 03/22/2021] [Indexed: 01/12/2023]
Abstract
Microbeads consisting of pullulan and dextran supplemented with hydroxyapatite have recently been developed for bone tissue engineering applications. Here, we evaluate the bone formation in two different preclinical models after injection of microbeads reconstituted with either saline buffer or autologous blood. Addition of saline solution or autologous blood to dried microbeads packaged into syringes allowed an easy injection. In the first rat bone defect model performed in the femoral condyle, microcomputed tomography performed after 30 and 60 days revealed an important mineralization process occurring around and within the core of the microbeads in both conditions. Bone volume/total volume measurements revealed no significant differences between the saline solution and the autologous blood groups. Histologically, osteoid tissue was evidenced around and in contact of the microbeads in both conditions. Using the sinus lift model performed in sheep, cone beam computed tomography revealed an important mineralization inside the sinus cavity for both groups after 3 months of implantation. Representative Masson trichrome staining images showed that bone formation occurs at the periphery and inside the microbeads in both conditions. Quantitative evaluation of the new bone formation displayed no significant differences between groups. In conclusion, reconstitution of microbeads with autologous blood did not enhance the regenerative capacity of these microbeads compared to the saline buffer group. This study is of particular interest for clinical applications in oral and maxillofacial surgery.
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Affiliation(s)
- Delphine B Maurel
- Tissue Bioengineering, INSERM U1026, University of Bordeaux, Bordeaux, France
| | - Mathilde Fénelon
- Tissue Bioengineering, INSERM U1026, University of Bordeaux, Bordeaux, France.,Department of Oral Surgery, CHU Bordeaux, Bordeaux, France
| | - Rachida Aid-Launais
- INSERM U1148, LVTS, Université Sorbonne Paris Nord, X Bichat Hospital, Université de Paris, Paris, France.,INSERM UMS-34, FRIM, X Bichat School of Medicine, Université de Paris, Paris, France
| | | | - Alice Le Nir
- Tissue Bioengineering, INSERM U1026, University of Bordeaux, Bordeaux, France.,Department of Oral Surgery, CHU Bordeaux, Bordeaux, France
| | | | - Jean-Christophe Fricain
- Tissue Bioengineering, INSERM U1026, University of Bordeaux, Bordeaux, France.,Department of Oral Surgery, CHU Bordeaux, Bordeaux, France
| | - Didier Letourneur
- INSERM U1148, LVTS, Université Sorbonne Paris Nord, X Bichat Hospital, Université de Paris, Paris, France.,SA, Zac de la Nau, SILTISS, Saint-Viance, France
| | - Joëlle Amédée
- Tissue Bioengineering, INSERM U1026, University of Bordeaux, Bordeaux, France
| | - Sylvain Catros
- Tissue Bioengineering, INSERM U1026, University of Bordeaux, Bordeaux, France.,Department of Oral Surgery, CHU Bordeaux, Bordeaux, France
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Kengelbach-Weigand A, Lotz L, Schmid R, Lang W, Beckmann MW, Hoffmann I, Horch RE, Renner SP, Dittrich R, Boos AM, Hildebrandt T. Intra- and Postoperative Blood Flow Monitoring in a Sheep Model of Uterus Transplantation. In Vivo 2019; 33:325-336. [PMID: 30804109 PMCID: PMC6506297 DOI: 10.21873/invivo.11478] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 01/24/2019] [Accepted: 01/28/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND The introduction of the opportunity to transplant a viable uterus into women for fulfilling their desire to have a child has awakened high expectations worldwide. MATERIALS AND METHODS A sheep model was used to evaluate tools for optimizing measurement of blood flow in uterine transplantation. Intraoperatively, blood flow was measured using unidirectional Doppler and indocyanine green (ICG) fluorescence imaging. Postoperatively, an implantable Doppler probe served as a tool for clinical monitoring the patency of anastomosed vessels. RESULTS ICG imaging showed complete vascularization of the uterus before and in short-term evaluation after surgery. The implantable Doppler probe proved to be highly suitable for assessing patency of vessels in a non-invasive way. Results of histology, and real-time polymerase chain reaction demonstrated viability of the transplanted uterus. CONCLUSION Different methods to monitor vasculature patency have proven to be advantageous in supporting both surgeons and researchers in ensuring successful implementation of uterine transplantation.
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Affiliation(s)
- Annika Kengelbach-Weigand
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Laura Lotz
- Department of Obstetrics and Gynecology, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Rafael Schmid
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Werner Lang
- Department of Vascular Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Matthias W Beckmann
- Department of Obstetrics and Gynecology, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Inge Hoffmann
- Department of Obstetrics and Gynecology, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Raymund E Horch
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Stefan P Renner
- Department of Obstetrics and Gynecology, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Ralf Dittrich
- Department of Obstetrics and Gynecology, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Anja M Boos
- Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
| | - Thomas Hildebrandt
- Department of Obstetrics and Gynecology, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen (FAU), Erlangen, Germany
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Gugjoo MB, Amarpal. Mesenchymal stem cell research in sheep: Current status and future prospects. Small Rumin Res 2018. [DOI: 10.1016/j.smallrumres.2018.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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6
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The impact of various scaffold components on vascularized bone constructs. J Craniomaxillofac Surg 2017; 45:881-890. [DOI: 10.1016/j.jcms.2017.02.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 01/23/2017] [Accepted: 02/14/2017] [Indexed: 01/01/2023] Open
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Weigand A, Beier JP, Schmid R, Knorr T, Kilian D, Götzl R, Gerber T, Horch RE, Boos AM. Bone Tissue Engineering Under Xenogeneic-Free Conditions in a Large Animal Model as a Basis for Early Clinical Applicability. Tissue Eng Part A 2017; 23:208-222. [PMID: 27998239 DOI: 10.1089/ten.tea.2016.0176] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
For decades, researchers have been developing a range of promising strategies in bone tissue engineering with the aim of producing a significant clinical benefit over existing therapies. However, a major problem concerns the traditional use of xenogeneic substances for the expansion of cells, which complicates direct clinical transfer. The study's aim was to establish a totally autologous sheep model as a basis for further preclinical studies and future clinical application. Ovine mesenchymal stromal cells (MSC) were cultivated in different concentrations (0%, 2%, 5%, 10%, and 25%) of either autologous serum (AS) or fetal calf serum (FCS). With an increase of serum concentration, enhanced metabolic activity and proliferation could be observed. There were minor differences between MSC cultivated in AS or FCS, comparing gene and protein expression of osteogenic and stem cell markers, morphology, and osteogenic differentiation. MSC implanted subcutaneously in the sheep model, together with a nanostructured bone substitute, either in stable block or moldable putty form, induced similar vascularization and remodeling of the bone substitute irrespective of cultivation of MSC in AS or FCS and osteogenic differentiation. The bone substitute in block form together with MSC proved particularly advantageous in the induction of ectopic bone formation compared to the cell-free control and putty form. It could be demonstrated that AS is suitable for replacement of FCS for cultivation of ovine MSC for bone tissue engineering purposes. Substantial progress has been made in the development of a strictly xenogeneic-free preclinical animal model to bring future clinical application of bone tissue engineering strategies within reach.
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Affiliation(s)
- Annika Weigand
- 1 Laboratory for Tissue Engineering and Regenerative Medicine, Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Erlangen, Germany
| | - Justus P Beier
- 1 Laboratory for Tissue Engineering and Regenerative Medicine, Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Erlangen, Germany
| | - Rafael Schmid
- 1 Laboratory for Tissue Engineering and Regenerative Medicine, Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Erlangen, Germany
| | - Tobias Knorr
- 1 Laboratory for Tissue Engineering and Regenerative Medicine, Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Erlangen, Germany
| | - David Kilian
- 1 Laboratory for Tissue Engineering and Regenerative Medicine, Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Erlangen, Germany
| | - Rebekka Götzl
- 1 Laboratory for Tissue Engineering and Regenerative Medicine, Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Erlangen, Germany
| | - Thomas Gerber
- 2 Institute of Physics, University of Rostock , Rostock, Germany
| | - Raymund E Horch
- 1 Laboratory for Tissue Engineering and Regenerative Medicine, Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Erlangen, Germany
| | - Anja M Boos
- 1 Laboratory for Tissue Engineering and Regenerative Medicine, Department of Plastic and Hand Surgery, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Erlangen, Germany
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8
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Ding M, Henriksen SS, Martinetti R, Overgaard S. 3D perfusion bioreactor-activated porous granules on implant fixation and early bone formation in sheep. J Biomed Mater Res B Appl Biomater 2016; 105:2465-2476. [PMID: 27655015 DOI: 10.1002/jbm.b.33783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 08/08/2016] [Accepted: 08/22/2016] [Indexed: 11/10/2022]
Abstract
Early fixation of total joint arthroplasties is crucial for ensuring implant survival. An alternative bone graft material in revision surgery is needed to replace the current gold standard, allograft, seeing that the latter is associated with several disadvantages. The incubation of such a construct in a perfusion bioreactor has been shown to produce viable bone graft materials. This study aimed at producing larger amounts of viable bone graft material (hydroxyapatite 70% and β-tricalcium-phosphate 30%) in a novel perfusion bioreactor. The abilities of the bioreactor-activated graft material to induce early implant fixation were tested in a bilateral implant defect model in sheep, with allograft as the control group. Defects were bilaterally created in the distal femurs of the animals, and titanium implants were inserted. The concentric gaps around the implants were randomly filled with either allograft, granules, granules with bone marrow aspirate or bioreactor-activated graft material. Following an observation time of 6 weeks, early implant fixation and bone formation were assessed by micro-CT scanning, mechanical testing, and histomorphometry. Bone formations were seen in all groups, while no significant differences between groups were found regarding early implant fixation. The microarchitecture of the bone formed by the synthetic graft materials resembled that of allograft. Histomorphometry revealed that allograft induced significantly more bone and less fibrous tissue (p < 0.05). In conclusion, bone formation was observed in all groups, while the bioreactor-activated graft material did not reveal additional effects on early implant fixation comparable to allograft in this model. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2465-2476, 2017.
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Affiliation(s)
- Ming Ding
- Orthopaedic Research Laboratory, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, J.B. Winsloewsvej 15, 3rd floor, DK-5000 Odense C, Denmark
| | - Susan S Henriksen
- Orthopaedic Research Laboratory, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, J.B. Winsloewsvej 15, 3rd floor, DK-5000 Odense C, Denmark
| | | | - Søren Overgaard
- Orthopaedic Research Laboratory, Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, J.B. Winsloewsvej 15, 3rd floor, DK-5000 Odense C, Denmark
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Weigand A, Horch RE, Beier JP, Arkudas A, Boos AM. Comment on 'Basic concepts regarding fractures healing and the current options and future directions in managing bone fractures'. Int Wound J 2015; 13:1080-2. [PMID: 26663542 DOI: 10.1111/iwj.12556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 11/16/2015] [Indexed: 11/30/2022] Open
Affiliation(s)
- Annika Weigand
- Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg FAU, Erlangen, Germany.
| | - Raymund E Horch
- Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg FAU, Erlangen, Germany
| | - Justus P Beier
- Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg FAU, Erlangen, Germany
| | - Andreas Arkudas
- Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg FAU, Erlangen, Germany
| | - Anja M Boos
- Department of Plastic and Hand Surgery and Laboratory for Tissue Engineering and Regenerative Medicine, University Hospital of Erlangen, Friedrich-Alexander University of Erlangen-Nürnberg FAU, Erlangen, Germany
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Weigand A, Beier JP, Hess A, Gerber T, Arkudas A, Horch RE, Boos AM. Acceleration of vascularized bone tissue-engineered constructs in a large animal model combining intrinsic and extrinsic vascularization. Tissue Eng Part A 2015; 21:1680-94. [PMID: 25760576 DOI: 10.1089/ten.tea.2014.0568] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
During the last decades, a range of excellent and promising strategies in Bone Tissue Engineering have been developed. However, the remaining major problem is the lack of vascularization. In this study, extrinsic and intrinsic vascularization strategies were combined for acceleration of vascularization. For optimal biomechanical stability of the defect site and simplifying future transition into clinical application, a primary stable and approved nanostructured bone substitute in clinically relevant size was used. An arteriovenous (AV) loop was microsurgically created in sheep and implanted, together with the bone substitute, in either perforated titanium chambers (intrinsic/extrinsic) for different time intervals of up to 18 weeks or isolated Teflon(®) chambers (intrinsic) for 18 weeks. Over time, magnetic resonance imaging and micro-computed tomography (CT) analyses illustrate the dense vascularization arising from the AV loop. The bone substitute was completely interspersed with newly formed tissue after 12 weeks of intrinsic/extrinsic vascularization and after 18 weeks of intrinsic/extrinsic and intrinsic vascularization. Successful matrix change from an inorganic to an organic scaffold could be demonstrated in vascularized areas with scanning electron microscopy and energy dispersive X-ray spectroscopy. Using the intrinsic vascularization method only, the degradation of the scaffold and osteoclastic activity was significantly lower after 18 weeks, compared with 12 and 18 weeks in the combined intrinsic-extrinsic model. Immunohistochemical staining revealed an increase in bone tissue formation over time, without a difference between intrinsic/extrinsic and intrinsic vascularization after 18 weeks. This study presents the combination of extrinsic and intrinsic vascularization strategies for the generation of an axially vascularized bone substitute in clinically relevant size using a large animal model. The additional extrinsic vascularization promotes tissue ingrowth and remodeling processes of the bone substitute. Extrinsic vessels contribute to faster vascularization and finally anastomose with intrinsic vasculature, allowing microvascular transplantation of the bone substitute after a shorter prevascularization time than using the intrinsic method only. It can be reasonably assumed that the usage of perforated chambers can significantly reduce the time until transplantation of bone constructs. Finally, this study paves the way for further preclinical testing for proof of the concept as a basis for early clinical applicability.
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Affiliation(s)
- Annika Weigand
- 1 Department of Plastic and Hand Surgery, University Hospital of Erlangen , Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
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