A bioengineered peripheral nerve construct using aligned peptide amphiphile nanofibers.

Peripheral nerve injuries can result in lifelong disability. Primary coaptation is the treatment of choice when the gap between transected nerve ends is short. Long nerve gaps seen in more complex injuries often require autologous nerve grafts or nerve conduits implemented into the repair. Nerve grafts, however, cause morbidity and functional loss at donor sites, which are limited in number. Nerve conduits, in turn, lack an internal scaffold to support and guide axonal regeneration, resulting in decreased efficacy over longer nerve gap lengths. By comparison, peptide amphiphiles (PAs) are molecules that can self-assemble into nanofibers, which can be aligned to mimic the native architecture of peripheral nerve. As such, they represent a potential substrate for use in a bioengineered nerve graft substitute. To examine this, we cultured Schwann cells with bioactive PAs (RGDS-PA, IKVAV-PA) to determine their ability to attach to and proliferate within the biomaterial. Next, we devised a PA construct for use in a peripheral nerve critical sized defect model. Rat sciatic nerve defects were created and reconstructed with autologous nerve, PLGA conduits filled with various forms of aligned PAs, or left unrepaired. Motor and sensory recovery were determined and compared among groups. Our results demonstrate that Schwann cells are able to adhere to and proliferate in aligned PA gels, with greater efficacy in bioactive PAs compared to the backbone-PA alone. In vivo testing revealed recovery of motor and sensory function in animals treated with conduit/PA constructs comparable to animals treated with autologous nerve grafts. Functional recovery in conduit/PA and autologous graft groups was significantly faster than in animals treated with empty PLGA conduits. Histological examinations also demonstrated increased axonal and Schwann cell regeneration within the reconstructed nerve gap in animals treated with conduit/PA constructs. These results indicate that PA nanofibers may represent a promising biomaterial for use in bioengineered peripheral nerve repair.

[1]  A. Chong,et al.  Early Clinical Experience With Collagen Nerve Tubes in Digital Nerve Repair , 2009 .

[2]  S. Mackinnon,et al.  Functional Evaluation of Complete Sciatic, Peroneal, and Posterior Tibial Nerve Lesions in the Rat , 1989, Plastic and reconstructive surgery.

[3]  Samuel I. Stupp,et al.  A Self-Assembly Pathway to Aligned Monodomain Gels , 2010, Nature materials.

[4]  Christine E Schmidt,et al.  Neural tissue engineering: strategies for repair and regeneration. , 2003, Annual review of biomedical engineering.

[5]  L. Yao,et al.  A biomaterials approach to peripheral nerve regeneration: bridging the peripheral nerve gap and enhancing functional recovery , 2012, Journal of The Royal Society Interface.

[6]  J. Hubbell,et al.  An RGD spacing of 440 nm is sufficient for integrin alpha V beta 3- mediated fibroblast spreading and 140 nm for focal contact and stress fiber formation , 1991, The Journal of cell biology.

[7]  P. Ducheyne,et al.  RGDS peptides immobilized on titanium alloy stimulate bone cell attachment, differentiation and confer resistance to apoptosis. , 2007, Journal of biomedical materials research. Part A.

[8]  J. Ecklund,et al.  History of peripheral nerve surgery techniques. , 2001, Neurosurgery clinics of North America.

[9]  Eric J Berns,et al.  Aligned neurite outgrowth and directed cell migration in self-assembled monodomain gels. , 2014, Biomaterials.

[10]  D. Boyd,et al.  FDA approved guidance conduits and wraps for peripheral nerve injury: a review of materials and efficacy. , 2012, Injury.

[11]  V. Carriel,et al.  Tissue engineering of the peripheral nervous system , 2014, Expert review of neurotherapeutics.

[12]  M. Wiberg,et al.  ECM molecules mediate both Schwann cell proliferation and activation to enhance neurite outgrowth. , 2007, Tissue engineering.

[13]  M. Millan,et al.  The induction of pain: an integrative review , 1999, Progress in Neurobiology.

[14]  I. Spigelman,et al.  Altered ATP release and metabolism in dorsal root ganglia of neuropathic rats , 2008, Molecular pain.

[15]  David J Mooney,et al.  Alginate type and RGD density control myoblast phenotype. , 2002, Journal of biomedical materials research.

[16]  G. Lawton,et al.  Shaping the military wound: issues surrounding the reconstruction of injured servicemen at the Royal Centre for Defence Medicine , 2011, Philosophical Transactions of the Royal Society B: Biological Sciences.

[17]  S. Stupp,et al.  Self‐assembling peptide amphiphile promotes plasticity of serotonergic fibers following spinal cord injury , 2010, Journal of neuroscience research.

[18]  P. Messersmith,et al.  Lipopeptides incorporated into supported phospholipid monolayers have high specific activity at low incorporation levels. , 2004, Journal of the American Chemical Society.

[19]  Nathan Swami,et al.  Alignment and composition of laminin-polycaprolactone nanofiber blends enhance peripheral nerve regeneration. , 2012, Journal of biomedical materials research. Part A.

[20]  A. Craig,et al.  Responses of spinothalamic lamina I neurons to repeated brief contact heat stimulation in the cat. , 2002, Journal of neurophysiology.

[21]  A. Rengarajan,et al.  Functional motor recovery after peripheral nerve repair with an aligned nanofiber tubular conduit in a rat model. , 2012, Regenerative medicine.

[22]  I. Ducic,et al.  Innovative Treatment of Peripheral Nerve Injuries: Combined Reconstructive Concepts , 2012, Annals of plastic surgery.

[23]  D. Irvine,et al.  Nanoscale clustering of RGD peptides at surfaces using Comb polymers. 1. Synthesis and characterization of Comb thin films. , 2001, Biomacromolecules.

[24]  J. Firrell,et al.  Functional Results of Vascularized versus Nonvascularized Nerve Grafting , 1992, Plastic and reconstructive surgery.

[25]  R. Langer,et al.  Prolonged Regional Nerve Blockade by Controlled Release of Local Anesthetic from a Biodegradable Polymer Matrix , 1993, Anesthesiology.

[26]  L G Griffith,et al.  Cell adhesion and motility depend on nanoscale RGD clustering. , 2000, Journal of cell science.

[27]  D. Ionescu,et al.  [Microsurgery on the peripheral nerves]. , 1984, Revista de chirurgie, oncologie, radiologie, o.r.l., oftalmologie, stomatologie. Chirurgie.

[28]  M. Yaszemski,et al.  Designing ideal conduits for peripheral nerve repair. , 2009, Neurosurgical focus.

[29]  Krista L. Niece,et al.  Selective Differentiation of Neural Progenitor Cells by High-Epitope Density Nanofibers , 2004, Science.

[30]  H. Ryoo,et al.  The effects of the modulation of the fibronectin-binding capacity of fibrin by thrombin on osteoblast differentiation. , 2012, Biomaterials.

[31]  M. Meek,et al.  Functional assessment of sciatic nerve recovery: biodegradable poly (DLLA‐ϵ‐CL) nerve guide filled with fresh skeletal muscle , 2003, Microsurgery.

[32]  Sing Yian Chew,et al.  Nanofibrous nerve conduit‐enhanced peripheral nerve regeneration , 2014, Journal of tissue engineering and regenerative medicine.

[33]  C. A. Hardin,et al.  Prognosis of nerve injuries incurred during acute trauma to peripheral arteries. , 1980, American journal of surgery.

[34]  M. Mrksich,et al.  The microenvironment of immobilized Arg-Gly-Asp peptides is an important determinant of cell adhesion. , 2001, Biomaterials.

[35]  Samuel I Stupp,et al.  Tubular hydrogels of circumferentially aligned nanofibers to encapsulate and orient vascular cells. , 2012, Biomaterials.

[36]  B. Wong,et al.  Experimental nerve regeneration. A review. , 1991, Otolaryngologic clinics of North America.

[37]  H. Millesi.  Microsurgery of Peripheral Nerves , 1973, World journal of surgery.

[38]  R Langer,et al.  Novel approach to fabricate porous sponges of poly(D,L-lactic-co-glycolic acid) without the use of organic solvents. , 1996, Biomaterials.

[39]  Kevin C. Chen,et al.  Scaffolds from block polyurethanes based on poly(ɛ-caprolactone) (PCL) and poly(ethylene glycol) (PEG) for peripheral nerve regeneration. , 2014, Biomaterials.

[40]  J. Gunn,et al.  Adhesive and mechanical properties of hydrogels influence neurite extension. , 2005, Journal of biomedical materials research. Part A.

[41]  L G Griffith,et al.  Nanoscale clustering of RGD peptides at surfaces using comb polymers. 2. Surface segregation of comb polymers in polylactide. , 2001, Biomacromolecules.

[42]  R. Kinne,et al.  Omental graft improves functional recovery of transected peripheral nerve , 2002, Muscle & nerve.

[43]  E. Diao,et al.  Engineering bi-layer nanofibrous conduits for peripheral nerve regeneration. , 2011, Tissue engineering. Part C, Methods.

[44]  Jung Keun Hyun,et al.  Phosphate glass fibres promote neurite outgrowth and early regeneration in a peripheral nerve injury model , 2015, Journal of tissue engineering and regenerative medicine.

[45]  Pedro Melo-Pinto,et al.  Methods for the experimental functional assessment of rat sciatic nerve regeneration , 2004, Neurological research.