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Eslahi N, Abdorahim M, Simchi A. Smart Polymeric Hydrogels for Cartilage Tissue Engineering: A Review on the Chemistry and Biological Functions. Biomacromolecules 2016; 17:3441-3463. [PMID: 27775329 DOI: 10.1021/acs.biomac.6b01235] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Stimuli responsive hydrogels (SRHs) are attractive bioscaffolds for tissue engineering. The structural similarity of SRHs to the extracellular matrix (ECM) of many tissues offers great advantages for a minimally invasive tissue repair. Among various potential applications of SRHs, cartilage regeneration has attracted significant attention. The repair of cartilage damage is challenging in orthopedics owing to its low repair capacity. Recent advances include development of injectable hydrogels to minimize invasive surgery with nanostructured features and rapid stimuli-responsive characteristics. Nanostructured SRHs with more structural similarity to natural ECM up-regulate cell-material interactions for faster tissue repair and more controlled stimuli-response to environmental changes. This review highlights most recent advances in the development of nanostructured or smart hydrogels for cartilage tissue engineering. Different types of stimuli-responsive hydrogels are introduced and their fabrication processes through physicochemical procedures are reported. The applications and characteristics of natural and synthetic polymers used in SRHs are also reviewed with an outline on clinical considerations and challenges.
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Affiliation(s)
- Niloofar Eslahi
- Department of Textile Engineering, Science and Research Branch, Islamic Azad University , P.O. Box 14515/775, Tehran, Iran
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52
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Khaing ZZ, Ehsanipour A, Hofstetter CP, Seidlits SK. Injectable Hydrogels for Spinal Cord Repair: A Focus on Swelling and Intraspinal Pressure. Cells Tissues Organs 2016; 202:67-84. [DOI: 10.1159/000446697] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2016] [Indexed: 11/19/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating condition that leaves patients with limited motor and sensory function at and below the injury site, with little to no hope of a meaningful recovery. Because of their ability to mimic multiple features of central nervous system (CNS) tissues, injectable hydrogels are being developed that can participate as therapeutic agents in reducing secondary injury and in the regeneration of spinal cord tissue. Injectable biomaterials can provide a supportive substrate for tissue regeneration, deliver therapeutic factors, and regulate local tissue physiology. Recent reports of increasing intraspinal pressure after SCI suggest that this physiological change can contribute to injury expansion, also known as secondary injury. Hydrogels contain high water content similar to native tissue, and many hydrogels absorb water and swell after formation. In the case of injectable hydrogels for the spinal cord, this process often occurs in or around the spinal cord tissue, and thus may affect intraspinal pressure. In the future, predictable swelling properties of hydrogels may be leveraged to control intraspinal pressure after injury. Here, we review the physiology of SCI, with special attention to the current clinical and experimental literature, underscoring the importance of controlling intraspinal pressure after SCI. We then discuss how hydrogel fabrication, injection, and swelling can impact intraspinal pressure in the context of developing injectable biomaterials for SCI treatment.
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53
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Combination of a peptide-modified gellan gum hydrogel with cell therapy in a lumbar spinal cord injury animal model. Biomaterials 2016; 105:38-51. [PMID: 27505621 DOI: 10.1016/j.biomaterials.2016.07.019] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/09/2016] [Accepted: 07/16/2016] [Indexed: 12/30/2022]
Abstract
Spinal Cord Injury (SCI) is a highly incapacitating condition for which there is still no cure. Current clinical approaches are mainly based on palliative care, so there is a need to find possible treatments to SCI. Cellular transplantation is regarded with great expectation due to the therapeutic potential of cells such as Adipose tissue-derived Stromal/Stem Cells (ASCs) or Olfactory Ensheathing Cells (OECs). Both are accessible sources and present positive paracrine and cell-to-cell interactions, previously reported by our group. Additionally, biomaterials such as hydrogels have been applied in SCI repair with promising results. We propose to combine a GRGDS-modified gellan gum hydrogel with ASCs and OECs in order to promote SCI regeneration. In vitro, ASCs and OECs could be co-cultured within GG-GRGDS hydrogels inducing a more robust neurite outgrowth when compared to controls. In vivo experiments in a hemisection SCI rat model revealed that the administration of ASCs and OECs encapsulated in a GG-GRGDS hydrogel led to significant motor improvements when compared to both control (SCI) and hydrogel alone (GG-GRGDS) groups. This was accompanied by a decreased infiltration of inflammatory cells and astrocytes, and by an increased intensity of neurofilament. These results suggest evident gains induced by the encapsulation of ASCs and OECs in GG-GRGDS based hydrogels.
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54
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Pakulska MM, Miersch S, Shoichet MS. Designer protein delivery: From natural to engineered affinity-controlled release systems. Science 2016; 351:aac4750. [PMID: 26989257 DOI: 10.1126/science.aac4750] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Exploiting binding affinities between molecules is an established practice in many fields, including biochemical separations, diagnostics, and drug development; however, using these affinities to control biomolecule release is a more recent strategy. Affinity-controlled release takes advantage of the reversible nature of noncovalent interactions between a therapeutic protein and a binding partner to slow the diffusive release of the protein from a vehicle. This process, in contrast to degradation-controlled sustained-release formulations such as poly(lactic-co-glycolic acid) microspheres, is controlled through the strength of the binding interaction, the binding kinetics, and the concentration of binding partners. In the context of affinity-controlled release--and specifically the discovery or design of binding partners--we review advances in in vitro selection and directed evolution of proteins, peptides, and oligonucleotides (aptamers), aided by computational design.
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Affiliation(s)
- Malgosia M Pakulska
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Shane Miersch
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Molly S Shoichet
- Department of Chemical Engineering and Applied Chemistry, Institute of Biomaterials and Biomedical Engineering, and Donnelly Centre, University of Toronto, Toronto, Ontario, Canada. Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
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55
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Liu W, Saunders MJ, Bagia C, Freeman EC, Fan Y, Gawalt ES, Waggoner AS, Meng WS. Local retention of antibodies in vivo with an injectable film embedded with a fluorogen-activating protein. J Control Release 2016; 230:1-12. [PMID: 27038493 DOI: 10.1016/j.jconrel.2016.03.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 02/25/2016] [Accepted: 03/22/2016] [Indexed: 11/17/2022]
Abstract
Herein we report an injectable film by which antibodies can be localized in vivo. The system builds upon a bifunctional polypeptide consisting of a fluorogen-activating protein (FAP) and a β-fibrillizing peptide (βFP). The FAP domain generates fluorescence that reflects IgG binding sites conferred by Protein A/G (pAG) conjugated with the fluorogen malachite green (MG). A film is generated by mixing these proteins with molar excess of EAK16-II, a βFP that forms β-sheet fibrils at high salt concentrations. The IgG-binding, fluorogenic film can be injected in vivo through conventional needled syringes. Confocal microscopic images and dose-response titration experiments showed that loading of IgG into the film was mediated by pAG(MG) bound to the FAP. Release of IgG in vitro was significantly delayed by the bioaffinity mechanism; 26% of the IgG were released from films embedded with pAG(MG) after five days, compared to close to 90% in films without pAG(MG). Computational simulations indicated that the release rate of IgG is governed by positive cooperativity due to pAG(MG). When injected into the subcutaneous space of mouse footpads, film-embedded IgG were retained locally, with distribution through the lymphatics impeded. The ability to track IgG binding sites and distribution simultaneously will aid the optimization of local antibody delivery systems.
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Affiliation(s)
- Wen Liu
- Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, United States
| | - Matthew J Saunders
- Molecular Biosensor and Imaging Center and Carnegie Mellon University, Pittsburgh, PA 15213, United States; Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Christina Bagia
- Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, United States
| | - Eric C Freeman
- College of Engineering, University of Georgia, Athens, GA 30602, United States
| | - Yong Fan
- Institute of Cellular Therapeutics, Allegheny-Singer Research Institute, Pittsburgh, PA 15212, United States; Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Ellen S Gawalt
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282, United States; McGowan Institute for Regenerative Medicine, Pittsburgh, PA 15213, United States
| | - Alan S Waggoner
- Molecular Biosensor and Imaging Center and Carnegie Mellon University, Pittsburgh, PA 15213, United States; Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Wilson S Meng
- Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, United States.
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56
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Nagy-Smith K, Yamada Y, Schneider JP. Protein release from highly charged peptide hydrogel networks. J Mater Chem B 2016; 4:1999-2007. [PMID: 32263077 PMCID: PMC8244587 DOI: 10.1039/c5tb02137e] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogels are useful delivery vehicles for therapeutic proteins. The ability to control the rate of protein release is paramount to a gel's utility and, in part, defines its clinical application. Electrostatic interactions made between encapsulated protein and a gel's network represents one modality in which protein motility can be controlled. For many gels this strategy works well under low ionic strength solution conditions, but dramatically less so in solutions of physiologically relevant ionic strength where electrostatic interactions are more effectively screened. Herein, we find that highly charged self-assembling peptides can be used to prepare fibrillar hydrogels of sufficient electropotential to allow electrostatic-based control over protein release under physiological buffer conditions. Rheology shows that proteins, differing significantly in their isoelectric point, can be directly encapsulated within negatively- or positively-charged peptide hydrogel networks during the peptide self-assembly event leading to gelation. Bulk adsorption studies coupled with transmission electron microscopy shows that electrostatic interactions drive the association of protein to oppositely charged fibrils in the final gel state, which in turn, dictates the diffusion and retention of these macromolecules in the hydrogel network.
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Affiliation(s)
- Katelyn Nagy-Smith
- Chemical Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA.
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57
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Parker J, Mitrousis N, Shoichet MS. Hydrogel for Simultaneous Tunable Growth Factor Delivery and Enhanced Viability of Encapsulated Cells in Vitro. Biomacromolecules 2016; 17:476-84. [DOI: 10.1021/acs.biomac.5b01366] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- James Parker
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
- Donnelly
Centre, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | - Nikolaos Mitrousis
- Donnelly
Centre, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
- Institute
of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
| | - Molly S. Shoichet
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
- Donnelly
Centre, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
- Institute
of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario M5S 3G9, Canada
- Department
of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E1, Canada
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58
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Serizawa T, Fukuta H, Date T, Sawada T. Affinity-based release of polymer-binding peptides from hydrogels with the target segments of peptides. Chem Commun (Camb) 2016; 52:2241-4. [DOI: 10.1039/c5cc09016d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Peptides with affinities for the target segments of polymer hydrogels were identified by phage display methods and exhibited affinity-based release capability from the hydrogels. The sustained anticancer effects of the drug-conjugated peptides were also demonstrated by their release from the hydrogels.
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Affiliation(s)
- Takeshi Serizawa
- Department of Organic and Polymeric Materials
- Tokyo Institute of Technology
- Meguro-ku
- Japan
| | - Hiroki Fukuta
- Department of Organic and Polymeric Materials
- Tokyo Institute of Technology
- Meguro-ku
- Japan
| | - Takaaki Date
- Department of Organic and Polymeric Materials
- Tokyo Institute of Technology
- Meguro-ku
- Japan
| | - Toshiki Sawada
- Department of Organic and Polymeric Materials
- Tokyo Institute of Technology
- Meguro-ku
- Japan
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59
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Wilems TS, Sakiyama-Elbert SE. Sustained dual drug delivery of anti-inhibitory molecules for treatment of spinal cord injury. J Control Release 2015; 213:103-111. [PMID: 26122130 PMCID: PMC4691576 DOI: 10.1016/j.jconrel.2015.06.031] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/05/2015] [Accepted: 06/23/2015] [Indexed: 11/25/2022]
Abstract
Myelin-associated inhibitors (MAIs) and chondroitin sulfate proteoglycans (CSPGs) are major contributors to axon growth inhibition following spinal cord injury and limit functional recovery. The NEP1-40 peptide competitively binds the Nogo receptor and partially blocks inhibition from MAIs, while chondroitinase ABC (ChABC) enzymatically digests CSPGs, which are upregulated at the site of injury. In vitro studies showed that the combination of ChABC and NEP1-40 increased neurite extension compared to either treatment alone when dissociated embryonic dorsal root ganglia were seeded onto inhibitory substrates containing both MAIs and CSPGs. Furthermore, the ability to provide sustained delivery of biologically active ChABC and NEP1-40 from biomaterial scaffolds was achieved by loading ChABC into lipid microtubes and NEP1-40 into poly (lactic-co-glycolic acid) (PLGA) microspheres, obviating the need for invasive intrathecal pumps or catheters. Fibrin scaffolds embedded with the drug delivery systems (PLGA microspheres and lipid microtubes) were capable of releasing active ChABC for up to one week and active NEP1-40 for over two weeks in vitro. In addition, the loaded drug delivery systems in fibrin scaffolds decreased CSPG deposition and development of a glial scar, while also increasing axon growth after spinal cord injury in vivo. Therefore, the sustained, local delivery of ChABC and NEP1-40 within the injured spinal cord may block both myelin and CSPG-associated inhibition and allow for improved axon growth.
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Affiliation(s)
- Thomas S Wilems
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, United States
| | - Shelly E Sakiyama-Elbert
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, United States.
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60
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Pakulska MM, Vulic K, Tam RY, Shoichet MS. Hybrid Crosslinked Methylcellulose Hydrogel: A Predictable and Tunable Platform for Local Drug Delivery. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:5002-5008. [PMID: 26184559 DOI: 10.1002/adma.201502767] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Indexed: 06/04/2023]
Abstract
Design of experiment is used to develop a hybrid methylcellulose hydrogel that combines physical and chemical crosslinks, resulting in an injectable, in situ stiffening, and long-lasting material with predictable swelling and rheological properties. Chemical crosslinking is complete prior to injection, allowing for ease of use and storage. Controlled release of two relevant protein therapeutics and biocompatibility of the hydrogel are demonstrated.
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Affiliation(s)
- Malgosia M Pakulska
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, ON, M5S 3E5, Canada
- Institute for Biomaterials and Bioengineering, University of Toronto, 164 College St., Rm 407, Toronto, ON, M5S 3G9, Canada
| | - Katarina Vulic
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada
| | - Roger Y Tam
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, ON, M5S 3E5, Canada
- Institute for Biomaterials and Bioengineering, University of Toronto, 164 College St., Rm 407, Toronto, ON, M5S 3G9, Canada
| | - Molly S Shoichet
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, ON, M5S 3E5, Canada
- Institute for Biomaterials and Bioengineering, University of Toronto, 164 College St., Rm 407, Toronto, ON, M5S 3G9, Canada
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada
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61
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Kabu S, Gao Y, Kwon BK, Labhasetwar V. Drug delivery, cell-based therapies, and tissue engineering approaches for spinal cord injury. J Control Release 2015; 219:141-154. [PMID: 26343846 DOI: 10.1016/j.jconrel.2015.08.060] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/23/2015] [Accepted: 08/31/2015] [Indexed: 12/28/2022]
Abstract
Spinal cord injury (SCI) results in devastating neurological and pathological consequences, causing major dysfunction to the motor, sensory, and autonomic systems. The primary traumatic injury to the spinal cord triggers a cascade of acute and chronic degenerative events, leading to further secondary injury. Many therapeutic strategies have been developed to potentially intervene in these progressive neurodegenerative events and minimize secondary damage to the spinal cord. Additionally, significant efforts have been directed toward regenerative therapies that may facilitate neuronal repair and establish connectivity across the injury site. Despite the promise that these approaches have shown in preclinical animal models of SCI, challenges with respect to successful clinical translation still remain. The factors that could have contributed to failure include important biologic and physiologic differences between the preclinical models and the human condition, study designs that do not mirror clinical reality, discrepancies in dosing and the timing of therapeutic interventions, and dose-limiting toxicity. With a better understanding of the pathobiology of events following acute SCI, developing integrated approaches aimed at preventing secondary damage and also facilitating neuroregenerative recovery is possible and hopefully will lead to effective treatments for this devastating injury. The focus of this review is to highlight the progress that has been made in drug therapies and delivery systems, and also cell-based and tissue engineering approaches for SCI.
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Affiliation(s)
- Shushi Kabu
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Yue Gao
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Brian K Kwon
- Department of Orthopaedics, International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, Canada V5Z 1M9
| | - Vinod Labhasetwar
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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62
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Study the effect of His-tag on chondroitinase ABC I based on characterization of enzyme. Int J Biol Macromol 2015; 78:96-101. [DOI: 10.1016/j.ijbiomac.2015.03.068] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 03/21/2015] [Accepted: 03/26/2015] [Indexed: 11/22/2022]
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63
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Papastefanaki F, Matsas R. From demyelination to remyelination: the road toward therapies for spinal cord injury. Glia 2015; 63:1101-25. [PMID: 25731941 DOI: 10.1002/glia.22809] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/10/2015] [Accepted: 02/11/2015] [Indexed: 12/14/2022]
Abstract
Myelin integrity is crucial for central nervous system (CNS) physiology while its preservation and regeneration after spinal cord injury (SCI) is key to functional restoration. Disturbance of nodal organization acutely after SCI exposes the axon and triggers conduction block in the absence of overt demyelination. Oligodendrocyte (OL) loss and myelin degradation follow as a consequence of secondary damage. Here, we provide an overview of the major biological events and underlying mechanisms leading to OL death and demyelination and discuss strategies to restrain these processes. Another aspect which is critical for SCI repair is the enhancement of endogenously occurring spontaneous remyelination. Recent findings have unveiled the complex roles of innate and adaptive immune responses in remyelination and the immunoregulatory potential of the glial scar. Moreover, the intimate crosstalk between neuronal activity, oligodendrogenesis and myelination emphasizes the contribution of rehabilitation to functional recovery. With a view toward clinical applications, several therapeutic strategies have been devised to target SCI pathology, including genetic manipulation, administration of small therapeutic molecules, immunomodulation, manipulation of the glial scar and cell transplantation. The implementation of new tools such as cellular reprogramming for conversion of one somatic cell type to another or the use of nanotechnology and tissue engineering products provides additional opportunities for SCI repair. Given the complexity of the spinal cord tissue after injury, it is becoming apparent that combinatorial strategies are needed to rescue OLs and myelin at early stages after SCI and support remyelination, paving the way toward clinical translation.
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Affiliation(s)
- Florentia Papastefanaki
- Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, Athens, 11521, Greece
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64
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Vo TTN, Meere MG. A Mathematical Model for the Release of Peptide-Binding Drugs from Affinity Hydrogels. Cell Mol Bioeng 2015. [DOI: 10.1007/s12195-014-0375-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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65
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Abstract
Three theories of regeneration dominate neuroscience today, all purporting to explain why the adult central nervous system (CNS) cannot regenerate. One theory proposes that Nogo, a molecule expressed by myelin, prevents axonal growth. The second theory emphasizes the role of glial scars. The third theory proposes that chondroitin sulfate proteoglycans (CSPGs) prevent axon growth. Blockade of Nogo, CSPG, and their receptors indeed can stop axon growth in vitro and improve functional recovery in animal spinal cord injury (SCI) models. These therapies also increase sprouting of surviving axons and plasticity. However, many investigators have reported regenerating spinal tracts without eliminating Nogo, glial scar, or CSPG. For example, many motor and sensory axons grow spontaneously in contused spinal cords, crossing gliotic tissue and white matter surrounding the injury site. Sensory axons grow long distances in injured dorsal columns after peripheral nerve lesions. Cell transplants and treatments that increase cAMP and neurotrophins stimulate motor and sensory axons to cross glial scars and to grow long distances in white matter. Genetic studies deleting all members of the Nogo family and even the Nogo receptor do not always improve regeneration in mice. A recent study reported that suppressing the phosphatase and tensin homolog (PTEN) gene promotes prolific corticospinal tract regeneration. These findings cannot be explained by the current theories proposing that Nogo and glial scars prevent regeneration. Spinal axons clearly can and will grow through glial scars and Nogo-expressing tissue under some circumstances. The observation that deleting PTEN allows corticospinal tract regeneration indicates that the PTEN/AKT/mTOR pathway regulates axonal growth. Finally, many other factors stimulate spinal axonal growth, including conditioning lesions, cAMP, glycogen synthetase kinase inhibition, and neurotrophins. To explain these disparate regenerative phenomena, I propose that the spinal cord has evolved regenerative mechanisms that are normally suppressed by multiple extrinsic and intrinsic factors but can be activated by injury, mediated by the PTEN/AKT/mTOR, cAMP, and GSK3b pathways, to stimulate neural growth and proliferation.
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Affiliation(s)
- Wise Young
- W. M. Keck Center for Collaborative Neuroscience, Rutgers, State University of New Jersey, Piscataway, NJ, USA
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66
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Expression, purification and thermostability of MBP-chondroitinase ABC I from Proteus vulgaris. Int J Biol Macromol 2015; 72:6-10. [DOI: 10.1016/j.ijbiomac.2014.07.040] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/15/2014] [Accepted: 07/15/2014] [Indexed: 11/21/2022]
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67
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Vulic K, Pakulska MM, Sonthalia R, Ramachandran A, Shoichet MS. Mathematical model accurately predicts protein release from an affinity-based delivery system. J Control Release 2014; 197:69-77. [PMID: 25449806 DOI: 10.1016/j.jconrel.2014.10.032] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 10/31/2014] [Indexed: 11/26/2022]
Abstract
Affinity-based controlled release modulates the delivery of protein or small molecule therapeutics through transient dissociation/association. To understand which parameters can be used to tune release, we used a mathematical model based on simple binding kinetics. A comprehensive asymptotic analysis revealed three characteristic regimes for therapeutic release from affinity-based systems. These regimes can be controlled by diffusion or unbinding kinetics, and can exhibit release over either a single stage or two stages. This analysis fundamentally changes the way we think of controlling release from affinity-based systems and thereby explains some of the discrepancies in the literature on which parameters influence affinity-based release. The rate of protein release from affinity-based systems is determined by the balance of diffusion of the therapeutic agent through the hydrogel and the dissociation kinetics of the affinity pair. Equations for tuning protein release rate by altering the strength (KD) of the affinity interaction, the concentration of binding ligand in the system, the rate of dissociation (koff) of the complex, and the hydrogel size and geometry, are provided. We validated our model by collapsing the model simulations and the experimental data from a recently described affinity release system, to a single master curve. Importantly, this mathematical analysis can be applied to any single species affinity-based system to determine the parameters required for a desired release profile.
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Affiliation(s)
- Katarina Vulic
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3E1, Canada; The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Malgosia M Pakulska
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E1, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3E1, Canada; The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Rohit Sonthalia
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Arun Ramachandran
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E1, Canada.
| | - Molly S Shoichet
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3E1, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E1, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3E1, Canada; The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada.
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68
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Abstract
Even after 20 years of granting orphan status for chondroitinase by US FDA, there is no visible outcome in terms of clinical use. The reasons are many. One of them could be lack of awareness regarding the biological application of the enzyme. The biological activity of chondroitinase is due to its ability to act on chondroitin sulfate proteoglycans (CSPGs). CSPGs are needed for normal functioning of the body. An increase or decrease in the level of CSPGs results in various pathological conditions. Chondroitinase is useful in conditions where there is an increase in the level of CSPGs, namely spinal cord injury, vitreous attachment and cancer. Over the last decade, various animal studies showed that chondroitinase could be a good drug candidate. Research focusing on developing a suitable carrier system for delivering chondroitinase needs to be carried out so that pharmacological activity observed in vitro and preclinical studies could be translated to clinical use. Further studies on distribution of chondroitinase as well need to be focused so that chondroitinase with desired attributes could be discovered. The present review article discusses about various biological applications of chondroitinase, drug delivery systems to deliver the enzyme and distribution of chondroitinase among microbes.
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Affiliation(s)
- Narayanan Kasinathan
- a Department of Pharmaceutical Biotechnology , Manipal College of Pharmaceutical Sciences, Manipal College of Pharmaceutical Sciences, Manipal University , Manipal , Karnataka , India
| | - Subrahmanyam M Volety
- a Department of Pharmaceutical Biotechnology , Manipal College of Pharmaceutical Sciences, Manipal College of Pharmaceutical Sciences, Manipal University , Manipal , Karnataka , India
| | - Venkata Rao Josyula
- a Department of Pharmaceutical Biotechnology , Manipal College of Pharmaceutical Sciences, Manipal College of Pharmaceutical Sciences, Manipal University , Manipal , Karnataka , India
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Vulic K, Shoichet MS. Affinity-Based Drug Delivery Systems for Tissue Repair and Regeneration. Biomacromolecules 2014; 15:3867-80. [DOI: 10.1021/bm501084u] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Katarina Vulic
- Department of Chemistry, ‡Department of Chemical
Engineering and Applied Chemistry, §Institute of Biomaterials
and Biomedical Engineering, Donnelly Centre, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
| | - Molly S. Shoichet
- Department of Chemistry, ‡Department of Chemical
Engineering and Applied Chemistry, §Institute of Biomaterials
and Biomedical Engineering, Donnelly Centre, University of Toronto, 160 College Street, Toronto, Ontario M5S3E1, Canada
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70
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Elliott Donaghue I, Tam R, Sefton MV, Shoichet MS. Cell and biomolecule delivery for tissue repair and regeneration in the central nervous system. J Control Release 2014; 190:219-27. [DOI: 10.1016/j.jconrel.2014.05.040] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/12/2014] [Accepted: 05/20/2014] [Indexed: 11/25/2022]
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Ramburrun P, Kumar P, Choonara YE, Bijukumar D, du Toit LC, Pillay V. A review of bioactive release from nerve conduits as a neurotherapeutic strategy for neuronal growth in peripheral nerve injury. BIOMED RESEARCH INTERNATIONAL 2014; 2014:132350. [PMID: 25143934 PMCID: PMC4131113 DOI: 10.1155/2014/132350] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/04/2014] [Indexed: 02/07/2023]
Abstract
Peripheral nerve regeneration strategies employ the use of polymeric engineered nerve conduits encompassed with components of a delivery system. This allows for the controlled and sustained release of neurotrophic growth factors for the enhancement of the innate regenerative capacity of the injured nerves. This review article focuses on the delivery of neurotrophic factors (NTFs) and the importance of the parameters that control release kinetics in the delivery of optimal quantities of NTFs for improved therapeutic effect and prevention of dose dumping. Studies utilizing various controlled-release strategies, in attempt to obtain ideal release kinetics, have been reviewed in this paper. Release strategies discussed include affinity-based models, crosslinking techniques, and layer-by-layer technologies. Currently available synthetic hollow nerve conduits, an alternative to the nerve autografts, have proven to be successful in the bridging and regeneration of primarily the short transected nerve gaps in several patient cases. However, current research emphasizes on the development of more advanced nerve conduits able to simulate the effectiveness of the autograft which includes, in particular, the ability to deliver growth factors.
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Affiliation(s)
- Poornima Ramburrun
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Pradeep Kumar
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Yahya E. Choonara
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Divya Bijukumar
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Lisa C. du Toit
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
| | - Viness Pillay
- Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa
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72
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Rodda AE, Meagher L, Nisbet DR, Forsythe JS. Specific control of cell–material interactions: Targeting cell receptors using ligand-functionalized polymer substrates. Prog Polym Sci 2014. [DOI: 10.1016/j.progpolymsci.2013.11.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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73
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Burnside ER, Bradbury EJ. Review: Manipulating the extracellular matrix and its role in brain and spinal cord plasticity and repair. Neuropathol Appl Neurobiol 2014; 40:26-59. [DOI: 10.1111/nan.12114] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/20/2013] [Indexed: 12/17/2022]
Affiliation(s)
- E. R. Burnside
- King's College London; Regeneration Group; The Wolfson Centre for Age-Related Diseases; Guy's Campus; London UK
| | - E. J. Bradbury
- King's College London; Regeneration Group; The Wolfson Centre for Age-Related Diseases; Guy's Campus; London UK
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74
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Tam RY, Fuehrmann T, Mitrousis N, Shoichet MS. Regenerative therapies for central nervous system diseases: a biomaterials approach. Neuropsychopharmacology 2014; 39:169-88. [PMID: 24002187 PMCID: PMC3857664 DOI: 10.1038/npp.2013.237] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 07/09/2013] [Accepted: 07/12/2013] [Indexed: 02/07/2023]
Abstract
The central nervous system (CNS) has a limited capacity to spontaneously regenerate following traumatic injury or disease, requiring innovative strategies to promote tissue and functional repair. Tissue regeneration strategies, such as cell and/or drug delivery, have demonstrated promising results in experimental animal models, but have been difficult to translate clinically. The efficacy of cell therapy, which involves stem cell transplantation into the CNS to replace damaged tissue, has been limited due to low cell survival and integration upon transplantation, while delivery of therapeutic molecules to the CNS using conventional methods, such as oral and intravenous administration, have been limited by diffusion across the blood-brain/spinal cord-barrier. The use of biomaterials to promote graft survival and integration as well as localized and sustained delivery of biologics to CNS injury sites is actively being pursued. This review will highlight recent advances using biomaterials as cell- and drug-delivery vehicles for CNS repair.
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Affiliation(s)
- Roger Y Tam
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada,Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada
| | - Tobias Fuehrmann
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada,Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada
| | - Nikolaos Mitrousis
- Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada
| | - Molly S Shoichet
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Donnelly Centre for Cellular and Biomolecular Research, Toronto, ON, Canada,Institute of Biomaterials and Biomedical Engineering, Toronto, ON, Canada,Department of Chemistry, University of Toronto, Toronto, ON, Canada,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Donnelly Centre for Cellular and Biomolecular Research, 160 College Street, Room 514, Toronto, ON, Canada, Tel: +416 978 1460, Fax: +416 978 4317, E-mail:
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