Seminar - Axon Stretch-Growth: Discovery of a New and Important Form of Nervous System Development
Date: March 8, 2005
Time: 10:00 AM
Location: Baiada Center, Room: Wedge Room
Dr. Bryan Pfister
Department of Neurosurgery,
University of Pennsylvania
Axon extension via its growth cone has been extensively studied as the primary form of axon growth. However, after an axon integrates with its target, the continued growth of an animal induces a distinct form of rapid axon growth as a result of mechanical stretching. Recently, we have demonstrated this form of axon stretch-growth in our laboratory.
We found that integrated axons spanning two populations of neurons in culture can be stretch grown at rates of up to 10mm/day, producing uniaxially aligned tracts up to 10cm in length and comprised of up to one million axons. Amazingly, stretch-grown axons increase in cross sectional area by 35%, maintain a normal cytoskeletal structure and retain the ability to generate action potentials. While providing insight into the mechanisms of axon growth during development, it is exciting to consider that axon stretch growth can be exploited to investigate numerous neurobiological questions.
Currently a postdoctoral fellow under the mentorship of Dr. Douglas Smith, Department of Neurosurgery, at the University of Pennsylvania, Dr. Pfister received his graduate degree from the Johns Hopkins University the areas of mechanical engineering and material science. As part of his dissertation, he developed an in vitro model to study the biomechanics of brain injury at the cellular level. Using this model to investigate the role of mechanical deformation and Bcl-2 protein expression in the development of axonal injury.
His current research has identified a fundamentally different form of axonal growth demonstrating that axon tracts can undergo rapid and sustained stretch-growth in laboratory culture. Exploiting this process, this research has led to the creation of transplantable nerve constructs spanned by living axon tracts, and are currently being evaluated in rat models of nerve injury. Dr. Pfister s research interests include neural tissue engineering, developmental neural biology, axon growth, mechanisms of neural injuries, and nervous system injury repair.
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