As collaborative efforts grow between rehabilitation scientists and those working in molecular/cellular technologies, physical therapists increasingly appreciate the relevance of regenerative rehabilitation and genomics in their research and practice. Traditionally, PTJ might not have been considered a natural home for papers focused on regenerative medicine and genomics, but the robust response to our call for papers suggests that the tide is turning. In fact, because of the number of submissions received, what started as a special issue has expanded into a special series. In this editorial introducing the first installment of the series, we provide a framework for the importance of this area to physical therapist practice and highlight the articles that inaugurate the series.
The Alliance for Regenerative Rehabilitation Research and Training (AR3T) defines regenerative rehabilitation as “the integration of principles and approaches from the fields of rehabilitation science and regenerative medicine.”1 Regenerative medicine focuses on the enhancement of endogenous stem cell function or the transplantation of exogenous stem cells to repair or replace tissue function that has been lost due to injury, disease, or aging. As such, the efficacy of rehabilitation interventions to restore physical functioning may be enhanced through the use of cellular and other regenerative therapies. Of no surprise to those in the rehabilitation field, regenerative medicine technologies have been shown to benefit from the application of targeted and specific mechanical stimuli. Advances in the field of regenerative medicine offer exciting new opportunities to enhance tissue regenerative capacity where the endogenous response fails, thereby opening up the scope of physical therapist practice where physical therapists are experts in the prescription of physical activity and modalities to promote tissue healing and recovery.
Physical Therapists Play a Role Both After and During the Regenerative Process
The potential to synergize rehabilitation practice and regenerative medicine technologies is elegantly outlined by Thompson et al2 in this issue. As they note, the concept of mechanical forces as a means to promote tissue healing is not new. According to Khan and Scott,3 in the late 19th century, the Oxford English Dictionary defined the term mechanotherapy as “the employment of mechanical means for the cure of disease.” Although mechanical stimulation has been a part of the history of physical therapy since our profession's inception, the underlying molecular and cellular mechanisms guiding tissue regenerative responses to physical forces have been all too often underappreciated. Here, Thompson and colleagues offer a contemporary view of mechanotherapy by canvassing principles of mechanobiology and its relevance to physical therapist practice. They offer a concise yet comprehensive primer of our current understanding of the cascade of events by which physical forces may be converted into targeted cellular and tissue responses. Importantly, they highlight the fact that physical therapists play a critical role in facilitating tissue function not only after regeneration has occurred but during the regenerative process. We believe this will be critical to the success of regenerative technologies, as physical therapy will undoubtedly be an indispensible tool for ensuring that the integration of regenerative medicine technologies into the host tissue is relevant in terms of function.
Building on this framework, Han et al4 present a case series that illustrates the potential of regenerative rehabilitation to influence physical therapist practice. They use nerve conduction studies and electromyography to evaluate physiological muscle properties following bioscaffold implantation—a tissue engineering approach—in 8 people with a chronic volumetric muscle loss injury. The goal of implantation of this acellular scaffold is to stimulate endogenous stem cell regenerative responses and promote the restoration of tissue function. Some individuals have dramatic increases in functional recovery following scaffold implantation, whereas others have only modest benefit, if any benefit at all. Clearly, the successful integration of this tissue engineering approach into clinical practice is dependent on selection of the most appropriate candidate for surgery and on a better understanding of physiological responses to scaffold implantation and how physical therapists may be able to optimize those responses in a patient-specific manner.
“The Genomic Era Is Upon Us”
The completion of the Human Genome Project in 2003 marked the dawn of the genomic era and the birth of personalized medicine. It provided a new understanding of the importance of genetics in predicting, diagnosing, and treating individual health conditions. Indeed, such personalized medicine has begun to impact virtually all areas of medicine, and physical therapy will be no different. Patient responses to rehabilitation interventions are notoriously variable despite apparent similarities in impairment profiles. One of the greatest challenges for any therapist is deciding which intervention is best suited for an individual patient. We are rapidly approaching an era when understanding genetic variation will help physical therapists better understand the individual differences contributing to impairment manifestation, treatment response, and overall patient wellness. Providing therapists with better tools for stratifying individual patients will undoubtedly enhance the impact of therapy.
Curtis et al5 review how genetics and personalized medicine have enhanced the ability to preserve wellness through diet and exercise and optimize treatment for cardiovascular disease and osteoarthritis. Curtis and colleagues show us that “the genomic era is upon us” and explain why physical therapists need to be prepared to include genomics as a factor in guiding patient wellness.
Another paper on genomics borrows from recent advances in functional neurogenomics showing the presence of genetic variations within genes encoding for “plasticity proteins” thought to mediate behavioral recovery. Kim and colleagues6 highlight that the presence of a single nucleotide polymorphism within the brain-derived neurotrophic factor (BDNF) gene is associated with altered patterns of brain activity in patients with stroke following robot-assisted motor rehabilitation. Patients who had the polymorphism demonstrated decreased brain activity during movement of the paretic hand in comparison with patients who did not have the polymorphism. Such changes in brain activity may be indicative of differential responses to motor rehabilitation.
The Next Generation
To wrap up this month's installment of the special series, Norland et al7 present an unprecedented Perspective—unprecedented because it is written from the point of view of doctorate of physical therapy (DPT) students. Under the mentorship of Dr. Rumit Kakar, DPT students from 4 different universities converged to survey DPT program faculty and students from across the country. The objective of the survey was to gauge the perceived importance of regenerative rehabilitation and genomics on physical therapist practice and how this perceived importance matches up with the incorporation of such concepts into DPT curricula. Compiling more than 1,000 survey responses, these authors bring to light a stark disconnect between “importance” and “incorporation.” Unfortunately, even though education programs generally recognize that innovative technologies are “highly relevant” to physical therapist practice, few programs effectively incorporate the material into their curricula. Based on these findings, the authors provide recommendations for bridging the gap between the basic sciences and education and for inspiring the next generation of physical therapist clinicians. Topp8 contributes a thoughtful “Program Director's Response” to the students' Perspective. She gives a historical framework for the need to incorporate innovative technologies into practice, references valuable resources available for those who want to learn more about the emerging fields of regenerative rehabilitation and genomics, and suggests targeted steps for ensuring that DPT students learn about state-of-the art technologies that will one day affect their clinical practice and research.
We hope that this special series on Regenerative Rehabilitation and Genomics will further stimulate discussion about the growing role of innovative technologies for rehabilitation practice and that manuscripts on these topics will continue to be submitted to PTJ to extend this series. We are so grateful to the authors who contributed to this series with their thought-provoking perspectives and cutting-edge research. We also sincerely appreciate the time and expertise provided by the reviewers, whose efforts greatly strengthened the impact of the series; they are listed here. Finally, we extend our heartfelt thanks to former Editor-in-Chief Dr. Rebecca Craik, who offered invaluable support and advice throughout the development of this series.
Appendix
Manuscript Reviewers for PTJ's Regenerative Rehabilitation and Genomics Special Series
Editor in Chief Alan Jette and former Editor in Chief Rebecca Craik, and Special Series Co-Editors Dr. Fabrisia Ambrosio and Dr. Jeffrey Kleim gratefully acknowledge the manuscript reviewers who contributed their time, expertise, and constructive comments to this special series.
Tracy Baker-Herman, PhD
Michele Crites Battié, PhD
Lara A. Boyd, PT, PhD
Steven Cramer, MD
Catherine L. Curtis, PT, EdD
Zoher F. Kapasi, PT, PhD
Karim Khan, MD, PhD
John Lawler, PhD
Richard M. Lovering, PT, PhD
Paula M. Ludewig, PT, PhD
David Mack, PhD
Gretchen A. Meyer, MD
D. Mirowska-Guzel, PhD
Michael Modo, PhD
Kirkwood (Kirk) Personius, PT, PhD
Darlene Reid, BMR, PhD
Darcy S. Reisman, PT, PhD
Heather H. Ross, PhD
David Russ, PT, PhD
Barbara K. Smith, PT, PhD
Gwendolyn Sowa, MD, PhD
Shiro Suda, MD
Carmen Terzic, MD, PhD
Kimberly S. Topp, PT, PhD
Samuel R. Ward, PT, PhD
Nick Willett, PT, PhD, OCS, CSCS
- © 2016 American Physical Therapy Association