Riyi Shi

Active Mentor - currently hosting PULSe students for laboratory rotations and recruiting PULSe students into the laboratory; serves on preliminary exam committees

Current Research Interests:

My laboratory is interested in the cellular and molecular underlying mechanism of nerve damage and recovery. We are particularly interested in the responses of the mammalian spinal cord following mechanical injury. We employ a noval double sucrose-gap chamber developed in this laboratory, for physiological recording and subsequently histological analysis of isolated guinea pig spinal cord. We have made progress in both understanding the nature of the injury as well as producing new potential treatments. For instance, we have been investigating the effect of 4-aminopyridine, a potassium channel blocker, in enhancing action potential conduction in chronic and acutely injured mammalian spinal cord. The search for other drugs with potential therapeutically value is also being conducted. Such studies provide strong support for the effective use of certain drugs (like 4-AP and methylprenisolone) in treating clinical spinal cord injury in man. We are also interested in the effects of physiological variables, such as ionic concentrations, O2 tension, temperature and pH in controlling membrane sealing after axonal damage. Sealing is a critical step in the recovery process following spinal cord injury. More recently, collaborating with Dr. Borgens, a new area of research has been identified. We have successfully reconnected two completely severed guinea pig spinal cord segments using a molecular surfactant (polyethylene glycol, or PEG). We have also shown that PEG can enhance the recovery of spinal cord following compression injury, a more clinically relevant type of injury. Currently, in vivo as well as in vitro investigations are underway to explore the clinical usage of PEG.

Selected Publications:

Hamann, K., Nehrt, G., Ouyang, H., Duerstock, D. and Shi, R. Hydralazine inhibits compression and acrolein-mediated injuries in ex vivo spinal cord. Journal of Neurochemistry. . 104: 708-718. 2008.

Ouyang, H., Galle, B., Li, J., Nauman, E., and Shi, R. Biomechanics of spinal cord injury: a multimodal investigation using ex vivo guinea pig spinal cord white matter. Journal of Neurotrauma. 25: 19-29. 2008.

Li, M., McNally, H. and Shi, R. Enhanced neurite alignment on micro-patterned poly-L-Lactic Acid films. Journal of Biomedical Materials Research: Part A. 87: 392-404. 2008.

Rickett, T., Li, M., Patel, M., Sun, W., Leung, G., and Shi, R. Ethyl-Cyanoacrylate is Acutely Non-Toxic and Provides Sufficient Bond Strength for Anastomosis of Peripheral Nerves. Journal of Biomedical Materials Research: Part A. In press. (2008 Jun 20. Epub ahead of print)

Cho, Y., Shi, R., Borgens, R., and Ivanisevic, A. The Functionalized Mesoporous Silica Nanoparticles (MSNs) Based Drug Delivery System to Rescue Acrolein-Mediated Cell Death. Nanomedicine. 3: 507-519. 2008

Cho, Y., Shi, R., Borgens, R and Ivanisevic, A. Repairing the damaged spinal cord and brain with nanomedicine. Small. 4: 1676-1681.2008.

*Hamann, K., Durkes, A., Ouyang, H., Pond, A., and Shi, R. Critical Role of acrolein in secondary injury following ex vivo spinal cord trauma. J. Neurochemistry. 107: 712-721. 2008. *selected by Faculty of 1000 Biology.

Ouyang, H., Galle, B., Li, J., Nauman, E., and Shi, R. Critical roles of decompression in functional recovery of ex vivo spinal cord white matter. Journal of Neurosurgery Spine. 10: 161-170. 2009.

Sun, W., Smith, D., Bryn, S., Borgens, R, and Shi, R. N-(4-pyridyl) methyl carbamate inhibits fast potassium currents in guinea pig dorsal root ganglion cells. Journal of Neurological Sciences. 277: 114-118. 2009.

Li, J., Rickett, T., and Shi, R. Biomimetic nerve scaffolds with aligned intraluminal microchannels: a sweet approach to tissue engineering. Langmuir. 25: 1813-1817. 2009

Chen, H., Quick, E., Leung, G., Hamann, K., Fu, Y., Cheng, J and Shi, R. Polyethylene Glycol protects injured neuronal mitochondria. Pathobiology. 76: 117-128, 2009.

Rickett, T., Li, M., Patel, M., Sun, W., Leung, G., and Shi, R. Ethyl-Cyanoacrylate is Acutely Non-Toxic and Provides Sufficient Bond Strength for Anastomosis of Peripheral Nerves. Journal of Biomedical Materials Research: Part A. 90:750-4. 2009.

Cho, Y., Shi, R., Ivanisevic, A., and Borgens, R. A mesoporous silica nanosphere-based drug delivery system using electrically condcting polymer. Nanotechnology. 20: 275102. 2009.

Fu, Y., Sun, W., Shi, Y. Shi*, R, and Cheng*, J. “Glutamate excitotoxicity inflicts paranodal myelin splitting and retraction.” PLoS ONE, 4(8): e6705. doi:10.1371/journal.pone.0006705, 2009. *: Co-correspondent author.

Hamann, K., and Shi, R. Acrolein scavenging: A potential novel mechanism of attenuating oxidative stress following spinal cord injury (invited review). J. Neurochem. 111: 1348-1356. 2009.

Shi, Y, Kim, S., Huff, T., Borgens, R., Park, K., Shi, R., and Cheng, J. Effective repair of traumatically injured spinal cord by block copolymer micelles: A pilot study. Nature Nanotechnology. 5:

Sun, W., Smith, D., Fu, Y., Cheng, J., Bryn, S., Borgens, R. and Shi, R. “A novel potassium channel blocker, 4-AP-3-MeOH, inhibits fast potassium channels and restores axonal conduction in injured guinea pig spinal cord white matter.” Journal of Neurophysiol. 103: 469-478. 2010.

Nehrt, A, Hammann, K., Ouyang, H., and Shi, R. Polyethylene glycol enhances axolemmal resealing following transetion in cultured cells and in ex vivo spinal cord. Journal of Neurotrauma. 27: 151-161, 2010.

Cho*, Y., Shi*, R., and Borgens, R. Chitosan nanoparticle-based neuronal membrane sealing and neuroprotection following acrolein-induced cell injury. Journal of Biological Engineering. 4:2, 2010. (open access: http://www.jbioleng.org/content/4/1/2). *: equal contribution.

Cho, Y., Shi, R., Ivanisevic, A., and Borgens, R. Functional silica nanoparticle-mediated neuronal membrane sealing following traumatic spinal cord injury. J. Neurosci. Res. 88, 1433-1444. 2010.

Cho, Y., Shi, R., and Borgens, R. Chiotosan produces potent Neuroprotection and physiological recovery following traumatic spinal cord injury. Journal of Experimental Biology. 213, 1513-1520. 2010.

Ouyang, H., Sun, W., Fu, Y., Li, J., Cheng, J., Nauman, E., and Shi, R. Compression induces acute demyelination and potassium channel exposure in spinal cord. J. Neurotrauma. 27: 1109-20. 2010.

Galle, B., Ouyang, H., Shi, R., and Nauman, E. A transversely isotropic constitutive model of excised guinea pig spinal cord white matter. J. Biomechanics. 43: 2839-43. 2010

Li, J., Kong, X., Gozani, S., Shi, R., and Borgens, B. Current-distance relationship for Peripheral Nerve stimulation localization. Anesth Analg In press.

Leung, G., Sun , W., Brookes, S, Smith, D., Shi, R. Potassium channel blocker, 4-Aminopyridine-3-Methanol, restores axonal conduction in spinal cord of an animal model of multiple sclerosis. Experimental Neurology In press.

Huang, J., Chen, J., Wang, W., Wang, Y., Wang, W., Wei, Y., Shi, R., Kaneko, T., Li, Y., Wu, S. Expression Pattern of Enkephalinergic Neurons in the Developing Spinal Cord Revealed by Preproenkephalin-Green Fluorescent Protein Transgenic Mouse and Its Colocalization with GABA Immunoreactivity. Cells Tissues Organs. In press.

Leung, G., Sun , W., Zheng, L., Brookes, S, Tully, M., and Shi, R. Anti-acrolein treatment improves behavioral outcome and alleviates myelin damage in EAE mouse. Neuroscience. In press.

Rickett, T., Amoozgar, Z., Tuchek, C., Park, J., Yeo, Y. and Riyi Shi. Rapidly Photo-Cross-Linkable Chitosan Hydrogel for Peripheral Neurosurgeries. Biomacromolecules. In press.