Pain may be a universal experience, but what actually causes that experience within our brains is still poorly understood. Pain often continues long after the relevant receptors in the body have stopped being stimulated and can persist even after those receptors cease to exist, as is the case with “phantom limb” pain.
The exact experience an individual will have after a painful incident comes down to the complex, variable connections formed between several different parts of the brain. The inability to predict how those connections will form and evolve can make pain management a tricky, frustrating endeavor for both healthcare providers and patients.
Now, a team of Penn researchers has shown a way to make such predictions from the pattern of neural connections that begin to take shape soon after the first onset of pain. Though their study was conducted in rats, it suggests that similar brain imaging techniques could be used to guide treatment decisions in humans, such as which individuals are most likely to benefit from different drugs or therapies.
The study, published in the journal Pain, was led by Beth Winkelstein, Eduardo D. Glandt President’s Distinguished Professor in Penn Engineering’s Department of Bioengineering and Deputy Provost of the University of Pennsylvania, along with Megan Sperry, then a graduate student in her lab. Eric Granquist, Director of the Center for Temporomandibular Joint Disease at the Hospital of the University of Pennsylvania in the Department of Oral & Maxillofacial Surgery, and assistant professor of Oral & Maxillofacial Surgery in Penn’s School of Dental Medicine, also contributed to the research.
“Our findings provide the first evidence that brain networks differ between acute and persistent pain states, even before those different groups of rats actually show different pain symptoms,” says Winkelstein.
Drugs are commonly injected directly into an injury site to speed healing. For chronic pain, clinicians can inject drugs to reduce inflammation in painful joints, or can inject nerve blockers to block the nerve signals that cause pain. In a recent study, a group from UCLA developed a technique to deform a material surrounding nerve fibers to trigger a response in the fibers that would relieve pain. The combination of mechanics and treatment – i.e., ‘mechanoceuticals’ – is a clever way to trick fibers and reverse painful symptoms. Done without any injections and simply controlling magnetic fields outside the body, this approach can be reused as necessary.
The design of this mechanoceutical was completed by Dino Di Carlo, PhD, Professor of Bioengineering, and his team at UCLA’s Sameuli School of Engineering. By encasing tiny, magnetic nanoparticles within a biocompatible hydrogel, the group used magnetic force to stimulate nerve fibers and cause a corresponding decrease in pain signals. This promising development opens up a new approach to pain management, one which can be created with different biomaterials to suit different conditions, and delivered “on demand” without worrying about injections or, for that matter, any prescription drugs.
Understanding the Adolescent Brain
It’s no surprise that adults and adolescents often struggle to understand one another, but the work of neurologists and other researchers provides a possible physical reason for why that might be. Magnetic resonance elastrography (MRE) is a tool used in biomedical imaging to estimate the mechanical properties, or stiffness, of tissue throughout the body. Unexpectedly, a recent study suggests that brain stiffness correlates with cognitive ability, suggesting MRE may provide insight into patients’ behavior, psychology, and psychiatric state.
A new paper in Developmental Cognitive Neuroscience published the results of a study using MRE to track the relative “stiffness” vs. “softness” of adult and adolescent brains. The University of Delaware team, led by Biomedical Engineering Assistant Professor Curtis Johnson, PhD, and his doctoral student Grace McIlvain, sampled 40 living subjects (aged 12-14) and compared the properties to healthy adult brains.
The study found that children and adolescent brains are softer than those of adults, correlating to the overall malleability of childhood development. The team hopes to continue their studies with younger and older children, looking to demonstrate exactly when and how the change from softness to stiffness takes place, and how these properties correspond to individual qualities such as risk-taking or the onset of puberty. Eventually, establishing a larger database of measurements in the pediatric brain will help further studies into neurological and cognitive disorders in children, helping to understand conditions such as multiple sclerosis, autism, and cerebral palsy.
Can Nanoparticles Replace Stents?
Researchers and clinicians have made amazing advances in heart surgery. Stents, in particular, have become quite sophisticated: they are used to both prop open clogged arteries as well as deliver blood-thinning medication slowly over days to weeks in the area of the stent. However, the risk of blood clotting increases with stents and the blood vessels can constrict over time after the stent is placed in the vessel.
A recent NIH grant will support the design of a stent-free solution to unclog blood vessels. Led by Shaoqin Gong, PhD, Vilas Distinguished Professor of Biomedical Engineering at UW-Madison, the team used nanoparticles (or nanoclusters) to directly target the affected blood vessels and prevent regrowth of the cells post-surgery, eliminating the need for a stent to keep the pathways open. These nanoclusters are injected through an intravenous line, further reducing the risks introduced by the presence of the stent. As heart disease affects millions of people worldwide, this new material has far-reaching consequences. Their study is published in the September edition of Biomaterials.
NIST Grant Supports
The National Institute of Standards and Technology (NIST) awarded a $30 million grant to Johns Hopkins University, Binghamton University, and Morgan State University as part of their Professional Research Experience Program (PREP). Over five years, this award will support the collaboration of academics from all levels (faculty, postdoc, graduate, and undergraduate) across the three universities, enabling them to conduct research and attend NIST conferences.
The principal investigator for Binghamton U. is Professor and Chair of the Biomedical Engineering Department, Kaiming Ye, PhD. Dr. Ye is also the Director of the Center of Biomanufacturing for Regenerative Medicine (CBRM), which will participate in this collaborative new enterprise. Dr. Ye hopes that this grant will create opportunities for academics and researchers to network with each other as well as to more precisely define the standards for the fields of regenerative medicine and biomaterial manufacturing.
The gift honors the late A. James Clark, former CEO of Clark Enterprises and Clark Construction Group LLC, one of the country’s largest privately-held general building contractors. It is designed to prepare future engineering and business leaders, with an emphasis on low income families and first-generation college students. Clark never forgot that his business successes began with an engineering scholarship. This has guided the Clark family’s longstanding investments in engineering education and reflects its commitment to ensure college remains accessible and affordable to high-potential students with financial need.
We are proud to say that three incoming Clark Scholars from the Freshman Class of 2022 will be part of the Bioengineering Department here at Penn.
And finally, our congratulations to the new Dean of the School of Engineering at the University of Mississippi: David A. Puleo, PhD. Dr. Puleo earned his bachelor’s degree and doctorate in Biomedical Engineering from Rensselaer Polytechnic Institute. Most recently he served as Professor of Biomedical Engineering and Associate Dean for Research and Graduate Studies at the University of Kentucky’s College of Engineering. Building on his research in regenerative biomaterials, he also founded Regenera Materials, LLC in 2014. Over the course of his career so far, Dr. Puleo received multiple teaching awards and oversaw much departmental growth within his previous institution, and looks poised to do the same for “Ole Miss.”
Pain is the body’s way of telling you there’s something wrong. For most of us, the pain goes away after the body fixes itself. However, more than 10% of Americans suffer from chronic pain after the healing period. Many chronic pain patients need drugs to reduce their symptoms. Given the pervasive use of opioid drugs to treat chronic pain, opioid addiction is common among chronic pain patients.
However, a remarkably clever and elegant cellular engineering technology may provide a new approach for treating chronic pain. Martin Fussenegger, Ph.D., a professor in the Department of Biosystems Science and Bioengineering at the Swiss Federal Institute of Technology, is the lead author of a new study published in Nature Biomedical Engineering combining cellular and genetic engineering to alleviate pain using cells as factories to produce spearmint. The strategy employed by the authors used engineered human cells to express huwentoxin IV, a blocker of sodium channels regulating pain signals in neurons, upon exposure to carvone, a terpenoid found in spearmint.
Testing their concept in a mouse model of pain, the authors found that mice exposed to spearmint both orally and via aromatherapy showed fewer signs of pain. Looking forward, Dr. Fussenegger and his colleagues believe that their technology, called AromaCell, should be tested next in human cell lines to alleviate concerns about immunological responses to the cells when implanted into patients.
Press Button to Bleed
Another recent article in Nature Biomedical Engineeringdetails the work of the Boston-area biotech firm Seventh Sense Biosystems on their push-button blood collection device, called TAP. As we have discussed here before, currently used blood-drawing procedures are often uncomfortable to patients because of the sharp needle prick used to collect blood. TAP was designed to collect 100 microliters of whole blood using a device the size of a stethoscope bell in a “virtually painless” manner.
The scientists from Seventh Sense designed the patch using microneedle technology. With this approach, they designed TAP with multiple microneedles deployed at high velocity to collect blood from capillaries — the tiniest vessels that connect veins and arteries and that lie closest to the surface of the skin — rather than from a vein tied off with a tourniquet. Testing the device in 144 volunteers, the study authors found that the device was as accurate as current methods for obtaining blood to measure hemoglobin (important for diabetics) and was significantly less painful.
Seventh Sense predicts this disposable device will cost only $5 per use, but this is still almost double the materials cost for standard blood draws. However, the company believes that the pain-free nature of and time saved with TAP will offset the higher cost of the device.
Advances in Global Health
The positively epidemic nature of human papilloma virus (HPV), affecting nearly one quarter of all Americans, has drawn particular attention over the last decade or so. The clear association between HPV and cervical cancer (as well as head and neck cancers) has led to the development and deployment of vaccines (controversial due to the sexually transmitted nature of HPV) and to increased calls for more regular and accurate screening. In developing nations, implementing either effective vaccination or early screening programs remains an uphill struggle.
Responding to the need for more accessible screening technologies, Jessica Ramella-Roman, Ph.D., Associate Professor of Biomedical Engineering at Florida International University (FIU), and Purnima Madhivanan, Ph.D., an epidemiology professor at FIU, traveled to Mysore, India, to install a device developed by Dr. Ramella-Roman at the Public Health Research Institute of India. The device is a hand-held imaging tool that uses a technology called Mueller matrix imaging to provide high-resolution digital images of the cervix in about 5 seconds. The resolution of the images eliminates the need to use dyes or stains to detect malignant cells. The testing of the device is currently ongoing.
Elsewhere in global health, researchers at Google have teamed with medical faculty from Stanford to produce a machine learning algorithm that could examine the human retina and determine whether the person in question is at risk for cardiovascular disease. They report their findings in Nature Biomedical Engineering.
The technology is not ready for actual patients yet — the study authors concede that the algorithm does not outperform the currently available technologies. However, if improved with additional research and testing, the algorithm could be deployed virtually anywhere, including in patients’ homes.
People and Places
Yale University has launched a new Center for Biomedical Data Science, dedicated to collecting, studying, and managing big data. The interim directors are Mark Gerstein, Ph.D., Albert L Williams Professor of Biomedical Informatics, Molecular Biophysics, and Biochemistry, and Hongyu Zhao, Ph.D., Ira V. Hiscock Professor of Biostatistics and Professor of Genetics and Professor of Statistics and Data Science.
The University of Virginia has announced a partnership with Smithfield Bioscience, a subsidiary of Smithfield Foods, Inc. The goal of the partnership is to advance a variety of tissue engineering applications using tissue samples from pigs. George J. Christ, Ph.D., Professor of Biomedical Engineering and Orthopaedic Surgery, heads UVA’s $3 million Center for Advanced Biomanufacturing, which is involved in the partnership.
Finally, we offer our congratulations to Guoqiang Yu, Ph.D., Professor of Biomedical Engineering at the University of Kentucky and a former research faculty member in physics here at Penn, for being awarded a two-year $420,000 R21 research grant from the NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development. Dr. Yu will use the money to develop a device to measure cerebral hemodynamics in neonatal ICU patients.
Zhiliang Cheng, Ph.D., a research assistant professor in the Department of Bioengineering at the University of Pennsylvania, has received an R01 grant from the National Institute of Neurological Disorders and Stroke to study chronic pain. The grant, which provides nearly $1.7 million over the next five years, will support the work of Dr. Cheng, Bioengineering Professor Andrew Tsourkas, and Vice Provost for Education and Professor Beth Winkelstein, in developing a novel nanotechnology platform for greater effectiveness in radiculopathy treatment.
Based on the idea that phospholipase-A2 (PLA2) enzymes, which modulate inflammation, play an important role in pain due to nerve damage, the group’s research seeks to develop PLA2-responsive multifunctional nanoparticles (PRMNs) that could both deliver anti-inflammatory drugs and magnetic resonance contrast agents to sites of pain so that the molecular mechanisms at work in producing chronic pain can be imaged, as well as allowing for the closer monitoring of treatment.
This research builds on previous findings by Drs. Cheng, Tsourkas, and Winkelstein. In a 2011 paper, Drs. Tsourkas and Winkelstein used superparamagnetic iron oxide nanoparticles to enhance magnetic resonance imaging of neurological injury in a rat model. Based on the theory of reactive oxygen species playing a role in pain following neural trauma, a subsequent paper published in July with Sonia Kartha as first author and Dr. Cheng as a coauthor found that a type of nanoparticle called polymersomes could be used to deploy superoxide dismutase, an antioxidant, to sites of neuropathic pain. The current grant-supported study combines the technologies developed in the previous studies.
“To the best of our knowledge, no studies have sought to combine and/or leverage this aspect of the inflammatory and PLA2 response for developing effective pain treatment. We hypothesize that this theranostic agent, which integrates both diagnostic and therapeutic functions into a single system, offers a unique opportunity and tremendous potential for monitoring and treating patients with direct, clinically translational impact,” Dr. Cheng said.