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Ruehle MA, Li MTA, Cheng A, Krishnan L, Willett NJ, Guldberg RE. Decorin-supplemented collagen hydrogels for the co-delivery of bone morphogenetic protein-2 and microvascular fragments to a composite bone-muscle injury model with impaired vascularization. Acta Biomater 2019; 93:210-221. [PMID: 30685477 PMCID: PMC6759335 DOI: 10.1016/j.actbio.2019.01.045] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 01/17/2019] [Accepted: 01/23/2019] [Indexed: 12/25/2022]
Abstract
Traumatic musculoskeletal injuries that result in bone defects or fractures often affect both bone and the surrounding soft tissue. Clinically, these types of multi-tissue injuries have increased rates of complications and long-term disability. Vascular integrity is a key clinical indicator of injury severity, and revascularization of the injury site is a critical early step of the bone healing process. Our lab has previously established a pre-clinical model of composite bone-muscle injury that exhibits impaired bone healing; however, the vascularization response in this model had not yet been investigated. Here, the early revascularization of a bone defect following composite injury is shown to be impaired, and subsequently the therapeutic potential of combined vascularization and osteoinduction was investigated to overcome the impaired regeneration in composite injuries. A decorin (DCN)-supplemented collagen hydrogel was developed as a biomaterial delivery vehicle for the co-delivery microvascular fragments (MVF), which are multicellular segments of mature vasculature, and bone morphogenetic protein-2 (BMP-2), a potent osteoinductive growth factor. We hypothesized that collagen + DCN would increase BMP-2 retention over collagen alone due to DCN's ability to sequester TGF-ß growth factors. We further hypothesized that MVF would increase both early vascularization and subsequent BMP-2-mediated bone regeneration. Contrary to our hypothesis, BMP + MVF decreased the number of blood vessels relative to BMP alone and had no effect on bone healing. However, collagen + DCN was demonstrated to be a BMP-2 delivery vehicle capable of achieving bridging in the challenging composite defect model that is comparable to that achieved with a well-established alginate-based delivery system. STATEMENT OF SIGNIFICANCE: We have previously established a model of musculoskeletal trauma that exhibits impaired bone healing. For the first time, this work shows that the early revascularization response is also significantly, albeit modestly, impaired. A decorin-supplemented collagen hydrogel was used for the first time in vivo as a delivery vehicle for both a cell-based vascular therapeutic, MVF, and an osteoinductive growth factor, BMP-2. While MVF did not improve vascular volume or bone healing, collagen + DCN is a BMP-2 delivery vehicle capable of achieving bridging in the challenging composite defect model. Based on its support of robust angiogenesis in vitro, collagen + DCN may be extended for future use with other vascular therapeutics such as pre-formed vascular networks.
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Affiliation(s)
- Marissa A Ruehle
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA, USA
| | - Mon-Tzu Alice Li
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA, USA
| | - Albert Cheng
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA; George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Laxminarayanan Krishnan
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Nick J Willett
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, GA, USA; Department of Orthopedics, Emory University, Atlanta, GA, USA; Research Service, Atlanta VA Medical Center, Decatur, GA, USA
| | - Robert E Guldberg
- Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA; Knight Campus for Accelerating Scientific Impact, University of Oregon, Eugene, OR, USA.
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