Program in Respiratory Neurobiology, Physiology and Rehabilitation

Injuries and diseases that compromise breathing are both debilitating and life-threatening. Respiratory insufficiency is associated with wide range of neurological and muscular pathologies, and is associated with pulmonary infection, reduced exercise tolerance. In extreme conditions, failure of the respiratory neuromuscular system requires long-term mechanical ventilator support. However, once ventilator support is initiated, weaning represents a major challenge. Ongoing research in the Dept. of Physical Therapy at the University of Florida is focused on respiratory system with an emphasis on rehabilitation. The goals of this research are 1) to understand the neuroplastic processes involved in the regulation of breathing; 2) to determine how the respiratory muscles adapt to chronic disease states; 3) to develop and optimize strategies for respiratory rehabilitation, and 4) to gain a detailed understanding of the physiological mechanisms underlying the success of respiratory rehabilitation. To this end, both clinical and basic science approaches are being used.

Dr. A.D. Martin’s clinical research focuses primarily on the development and implementation of respiratory rehabilitation programs for lung transplant and ventilator dependent patients. The traditional approach to mechanical ventilation has focused on optimizing medical care and the patient-ventilator interface. In contrast, Dr. Martin is using respiratory muscle training to offset the inspiratory muscle weakness that results from mechanical ventilation. He has found that inspiratory training with a pressure-threshold device rapidly (days-weeks) improves the overall performance of the inspiratory muscles. The ultimate goal of these treatment strategies is to decrease dependence on mechanical ventilation, allow extended periods of spontaneous respiration, and improve the speech production of treated patients.

Dr. B. Smith’s research examines the time course and extent of respiratory muscle remodeling in response to respiratory muscle overload training, using a combination of basic science and clinical approaches. Traditionally, it was thought that early training-induced respiratory strength gains were largely due to neural adaptations. Dr. Smith’s bench research illustrated that the diaphragm and synergist inspiratory muscles also undergo rapid remodeling during the first two weeks of respiratory muscle overload training. Moreover, it appears that the mechanisms of remodeling may vary between the ventilatory muscles. Her current research interests include 1) examining the biology of acute muscle remodeling following a respiratory overload, 2) using translational strategies to test respiratory muscle strength and function, 3) identifying the patterns of motor weakness and training-induced plasticity in respiratory neuromuscular diseases, and 4) measuring the effect of respiratory muscle strengthening in infants and children with Pompe disease. Her longer-term goals are to understand the muscular substrates of respiratory motor training, in order to facilitate compensation or recovery for patients with neuromuscular disease and impaired breathing.

Dr. D. Fuller is using a basic science approach to understand how neuroplasticity in the brain and spinal cord influences the control of the respiratory muscles. He is particularly interested in identifying treatments and neural mechanisms that enhance the function of spinal neurons and networks following spinal cord injury. Appropriate induction of neuroplasticity in the spinal cord has the potential to improve respiratory muscle control following injury, thereby reducing dependence on mechanical ventilators and improving the quality of life for spinally injured patients. Dr. Fuller’s laboratory uses neurophysiological techniques to explore mechanisms of plasticity influencing respiratory neuron, nerve and muscle behavior following high cervical spinal cord injury. Current projects focus on 1) the neural regulation of phrenic motoneurons and cervical interneurons following cervical spinal cord injury; 2) respiratory and upper extremity muscle plasticity after cervical spinal cord injury; 3) the use of cell replacement therapies (“spinal transplants”) in the cervical spinal cord; 4) the neural regulation of breathing in glycogen storage diseases, and 5) the use of AAV vectors for gene delivery to respiratory motoneurons.