Regrowing Amputated Limbs Is Getting Closer to Medical Reality
In June 2012, Kirstie Ennis was six months into her second deployment to Afghanistan and recently promoted to sergeant. The helicopter gunner and seven others were three hours into a routine mission of combat resupplies and troop transport when their CH-53D helicopter went down hard.
Miraculously, all eight people onboard survived, but Ennis' injuries were many and severe. She had a torn rotator cuff, torn labrum, crushed cervical discs, facial fractures, deep lacerations and traumatic brain injury. Despite a severely fractured ankle, doctors managed to save her foot, for a while at least.
In November 2015, after three years of constant pain and too many surgeries to count, Ennis relented. She elected to undergo a lower leg amputation but only after she completed the 1,000-mile, 72-day Walking with the Wounded journey across the UK.
On Veteran's Day of that year, on the other side of the country, orthopedic surgeon Cato Laurencin announced a moonshot challenge he was setting out to achieve on behalf of wounded warriors like Ennis: the Hartford Engineering A Limb (HEAL) Project.
Laurencin, who is a University of Connecticut professor of chemical, materials and biomedical engineering, teamed up with experts in tissue bioengineering and regenerative medicine from Harvard, Columbia, UC Irvine and SASTRA University in India. Laurencin and his colleagues at the Connecticut Convergence Institute for Translation in Regenerative Engineering made a bold commitment to regenerate an entire limb within 15 years – by the year 2030.
Dr. Cato Laurencin pictured in his office at UConn.
Photo Credit: UConn
Regenerative Engineering -- A Whole New Field
Limb regeneration in humans has been a medical and scientific fascination for decades, with little to show for the effort. However, Laurencin believes that if we are to reach the next level of 21st century medical advances, this puzzle must be solved.
An estimated 185,000 people undergo upper or lower limb amputation every year. Despite the significant advances in electromechanical prosthetics, these individuals still lack the ability to perform complex functions such as sensation for tactile input, normal gait and movement feedback. As far as Laurencin is concerned, the only clinical answer that makes sense is to regenerate a whole functional limb.
Laurencin feels other regeneration efforts were hampered by their siloed research methods with chemists, surgeons, engineers all working separately. Success, he argues, requires a paradigm shift to a trans-disciplinary approach that brings together cutting-edge technologies from disparate fields such as biology, material sciences, physical, chemical and engineering sciences.
As the only surgeon ever inducted into the academies of Science, Medicine and Innovation, Laurencin is uniquely suited for the challenge. He is regarded as the founder of Regenerative Engineering, defined as the convergence of advanced materials sciences, stem cell sciences, physics, developmental biology and clinical translation for the regeneration of complex tissues and organ systems.
But none of this is achievable without early clinician participation across scientific fields to develop new technologies and a deeper understanding of how to harness the body's innate regenerative capabilities. "When I perform a surgical procedure or something is torn or needs to be repaired, I count on the body being involved in regenerating tissue," he says. "So, understanding how the body works to regenerate itself and harnessing that ability is an important factor for the regeneration process."
The Birth of the Vision
Laurencin's passion for regeneration began when he was a sports medicine fellow at Cornell University Medical Center in the early 1990s. There he saw a significant number of injuries to the anterior cruciate ligament (ACL), the major ligament that stabilizes the knee. He believed he could develop a better way to address those injuries using biomaterials to regenerate the ligament. He sketched out a preliminary drawing on a napkin one night over dinner. He has spent the next 30 years regenerating tissues, including the patented L-C ligament.
As chair of Orthopaedic Surgery at the University of Virginia during the peak of the wars in Iraq and Afghanistan, Laurencin treated military personnel who survived because of improved helmets, body armor and battlefield medicine but were left with more devastating injuries, including traumatic brain injuries and limb loss.
"I was so honored to care for them and I so admired their steadfast courage that I became determined to do something big for them," says Laurencin.
When he tells people about his plans to regrow a limb, he gets a lot of eye rolls, which he finds amusing but not discouraging. Growing bone cells was relatively new when he was first focused on regenerating bone in 1987 at MIT; in 2007 he was well on his way to regenerating ligaments at UVA when many still doubted that ligaments could even be reconstructed. He and his team have already regenerated torn rotator cuff tendons and ACL ligaments using a nano-textured fabric seeded with stem cells.
Even as a finalist for the $4 million NIH Pioneer Award for high-risk/high-reward research, he faced a skeptical scientific audience in 2014. "They said, 'Well what do you plan to do?' I said 'I plan to regenerate a whole limb in people.' There was a lot of incredulousness. They stared at me and asked a lot of questions. About three days later, I received probably the best score I've ever gotten on an NIH grant."
In the Thick of the Science
Humans are born with regenerative abilities--two-year-olds have regrown fingertips--but lose that ability with age. Salamanders are the only vertebrates that can regenerate lost body parts as adults; axolotl, the rare Mexican salamander, can grow extra limbs.
The axolotl is important as a model organism because it is a four-footed vertebrate with a similar body plan to humans. Mapping the axolotl genome in 2018 enhanced scientists' genetic understanding of their evolution, development, and regeneration. Being easy to breed in captivity allowed the HEAL team to closely study these amphibians and discover a new cell type they believe may shed light on how to mimic the process in humans.
"Whenever limb regeneration takes place in the salamander, there is a huge amount of something called heparan sulfate around that area," explains Laurencin. "We thought, 'What if this heparan sulfate is the key ingredient to allowing regeneration to take place?' We found these groups of cells that were interspersed in tissues during the time of regeneration that seemed to have connections to each other that expressed this heparan sulfate."
Called GRID (Groups that are Regenerative, Interspersed and Dendritic), these cells were also recently discovered in mice. While GRID cells don't regenerate as well in mice as in salamanders, finding them in mammals was significant.
"If they're found in mice. we might be able to find these in humans in some form," Laurencin says. "We think maybe it will help us figure out regeneration or we can create cells that mimic what grid cells do and create an artificial grid cell."
What Comes Next?
Laurencin and his team have individually engineered and made every single tissue in the lower limb, including bone, cartilage, ligament, skin, nerve, blood vessels. Regenerating joints and joint tissue is the next big mile marker, which Laurencin sees as essential to regenerating a limb that functions and performs in the way he envisions.
"Using stem cells and amnion tissue, we can regenerate joints that are damaged, and have severe arthritis," he says. "We're making progress on all fronts, and making discoveries we believe are going to be helping people along the way."
That focus and advancement is vital to Ennis. After laboring over the decision to have her leg amputated below the knee, she contracted MRSA two weeks post-surgery. In less than a month, she went from a below-the-knee-amputee to a through-the-knee amputee to an above-the-knee amputee.
"A below-the-knee amputation is night-and-day from above-the-knee," she said. "You have to relearn everything. You're basically a toddler."
Kirstie Ennis pictured in July 2020.
Photo Credit: Ennis' Instagram
The clock is ticking on the timeline Laurencin set for himself. Nine years might seem like forever if you're doing time but it might appear fleeting when you're trying to create something that's never been done before. But Laurencin isn't worried. He's convinced time is on his side.
"Every week, I receive an email or a call from someone, maybe a mother whose child has lost a finger or I'm in communication with a disabled American veteran who wants to know how the progress is going. That energizes me to continue to work hard to try to create these sorts of solutions because we're talking about people and their lives."
He devotes about 60 hours a week to the project and the roughly 100 students, faculty and staff who make up the HEAL team at the Convergence Institute seem acutely aware of what's at stake and appear equally dedicated.
"We're in the thick of the science in terms of making this happen," says Laurencin. "We've moved from making the impossible possible to making the possible a reality. That's what science is all about."
Niklas Anzinger is the founder of Infinita VC based in the charter city of Prospera in Honduras. Infinita focuses on a new trend of charter cities and other forms of alternative jurisdictions. Healso hosts a podcast about how to accelerate the future by unblocking “stranded technologies”.This spring he was a part of the network city experiment Zuzalu spearheaded by Ethereum founder Vitalik Buterin where a few hundred invited guests from the spheres of longevity, biotechnology, crypto, artificial intelligence and investment came together to form a two-monthlong community. It has been described as the world’s first pop-up city. Every morning Vitalians would descend on a long breakfast—the menu had been carefully designed by famed radical longevity self-experimenter Bryan Johnson—and there is where I first met Anzinger who told me about Prospera. Intrigued to say the least, I caught up with him later the same week and the following is a record of our conversation.
Q. We are sitting here in the so-called pop-up network state Zuzalu temporarily realized in the village of Lusticia Bay by the beautiful Mediterranean Sea. To me this is an entirely new concept: What is a network state?
A. A network state is a highly aligned online community that has a level of in-person civility; it crowd-funds territory, and it eventually seeks diplomatic recognition. In a way it's about starting a new country. The term was coined by the crypto influencer and former CTO of Coinbase Balaji Srinivasan in a book by the same title last year [2022]. What many people don't know is that it is a more recent addition or innovation in a space called competitive governance. The idea is that you have multiple jurisdictions competing to provide you services as a customer. When you have competition among governments or government service providers, these entities are forced to provide you with a better service instead of the often worse service at higher prices or higher taxes that we're currently getting. The idea went from seasteading, which was hardly feasible because of costs, to charter cities getting public/private partnerships with existing governments and a level of legal autonomy, to special economic zones, to now network states.
Q. How do network states compare to charter cities and similar jurisdictions?
A. Charter cities and special economic zones were legal forks from other existing states. Dubai, Shenzhen in China, to some degree Hong Kong, to some degree Singapore are some examples. There's a host of other charter cities, one of which I'm based in myself, which is Prospera located in Honduras on the island Roatán. Charter cities provide the full stack of governance; they provide new laws and regulations, business registration, tax codes and governance services, Estonia style: you log on to the government platform and you get services as a citizen.
When conceptualizing network states, Balagi Srinivasan turns the idea of a charter city a bit on its head: he doesn't want to start with this full stack because it's still very hard to get these kinds of partnerships with government. It's very expensive and requires lots of experience and lots of social capital. He is saying that network states could instead start as an online community. They could have a level of alignment where they trade with each other; they have their own economy; they meet in person in regular gatherings like we're doing here in Zuzulu for two months, and then they negotiate with existing governments or host cities to get a certain degree of legal autonomy that is centered around a moral innovation. So, his idea is: don't focus on building a completely new country or city; focus on a moral innovation.
Q. What would be an example of such a moral innovation?
A. An example would be longevity—life is good; death is bad—let's see what we can do to foster progress around that moral innovation and see how we can get legal forks from the existing system that allow us to accelerate progress in that area. There is an increasing realization in the science that there are hallmarks of aging and that aging is a cause of other diseases like cancer, ALS or Alzheimer's. But aging is not recognized as a disease by the FDA in the United States and in most countries around the world, so it's very hard to get scientific funding for biotechnology that would attack the hallmarks of aging and allow us potentially to reverse aging and extend life. This is a significant shortcoming of existing government systems that groups such as the ones that have come together here in Montenegro are now seeking alternatives too. Charter cities and now network states are such alternatives.
Q. Would it not be better to work within the current systems, and try to improve them, rather than abandon them for new experimental jurisdictions?
A. There are numerous failures of public policies. These failures are hard, if not impossible, to reverse, because as soon as you have these policies, you have entrenched interests who benefit from the regulations. The only way to disrupt incumbent industries is with start-ups, but the way the system is set up makes it excessively hard for such start-ups to become big companies. In fact, larger companies are weaponizing the legal system against small companies, because they can afford the lawyers and the fixed cost of compliance.
I don't believe that our institutions in many developed countries are beyond hope. I just think it's easier to change them if you could point at successful examples. ‘Hey, this country or this zone is already doing it very successfully’; if they can extend people’s lifespan by 10 years, if they can reduce maternal mortality, and if they have a massive medical tourism where people come back healthier, then that is just very embarrassing for the FDA.
Q. Perhaps a comparison here would be the relationship between Hong Kong and China?
A. Correct, so having Hong Kong right in front of your door … ‘Hey, this capitalism thing seems to work, why don't we try it here?’ It was due to the very bold leadership by Deng Xiaoping that they experimented with it in the development zone of Shenzhen. It worked really well and then they expanded with more special economic zones that also worked.
Próspera is a private city and special economic zone on the island of Roatán in the Central American state of Honduras.
Q. Tell us about Prospera, the charter city in Honduras, that you are intimately connected with.
A. Honduras is a very poor country. It has a lot of crime, never had a single VC investment, and has a GDP per capita of 2,000 per year. Honduras has suffered tremendously. The goal of these special economic zones is to bring in economic development. That's their sole purpose. It's a homegrown innovation from Honduras that started in 2009 with a very forward-thinking statesman, Octavio Sanchez, who was the chief of staff to the president of Honduras, and then president. He had his own ideas about making Honduras a more decentralized system, where more of the power lies in the municipalities.
Inspired by the ideas of Nobel laureate economist Paul Romer, who gave a famous Ted Talk in 2009 about charter cities, Sanchez initiated a process that lasted for years and eventually led to the creation of a special economic zone legal regime that’s anchored in the Hunduran constitution that provides the highest legal autonomy in the world to these zones. There are today three special economic zones approved by the Honduran government: Prospera, Ciudad Morazan and Orchidea.
Q. How did you become interested and then involved in Prospera?
A. I read about it first in an article by Scott Alexander, a famous rationalist blogger, who wrote a very long article about Prospera, and I thought, this is amazing! Then I came to Prospera and I found it to be one of the most if not the most exciting project in the world going on right now and that it also opened my heart to the country and its people. Most of my friends there are Honduran, they have been working on this for 10 or more years. They want to remake Honduras and put it on the map as the place in the world where this legal and governance innovation started.
Q. To what extent is Prospera autonomous relative to the Honduran government?
A. What's interesting about the Honduran model is that it's anchored within the Honduran constitution, and it has a very clear framework for what's possible and what's not possible, and what's possible ensures the highest degree of legal autonomy anywhere seen in the world. Prospera has really pushed the model furthest in creating a common law-based polycentric legal system. The idea is that you don't have a legislature, instead you have common law and it's based on the best practice common law principles that a legal scholar named Tom W. Bell created.
One of the core ideas is that as a business you're not obligated to follow one regulatory monopoly like the FDA. You have regulatory flexibility so you can choose what you're regulated under. So, you can say: ‘if I do a medical clinic, I do it under Norwegian law here’. And you even have the possibility to amend it a bit. You're still required to have liability insurance, and have to agree to binding arbitration in case there's a legal dispute. And your insurance has to approve you. So, under that model the insurance becomes the regulator and they regulate through prices. The limiting factor is criminal law; Honduran criminal law fully applies. So does immigration law. And we pay taxes.
Q. Is there also an idea of creating a kind of healthy living there, and encourage medical tourism?
A. Yes, we specifically look for legal advantages in autonomy around creating new drugs, doing clinical trials, doing self-medication and experimentation. There is a stem cell clinic here and they're doing clinical trials. The island of Roatán is very easily accessible for American tourists. It's a beautiful island, and it's for regulatory reasons hard to do stem cell therapies in the United States, so they're flying in patients from the United States. Most of them are very savvy and often have PhDs in biotech and are able to assess the risk for themselves of taking drugs and doing clinical trials. We're also going to get a wellness center, and there have been ideas around establishing a peptide clinic and a compound pharmacy and things like that. We are developing a healthcare ecosystem.
Q. This kind of experimental tourism raises some ethical issues. What happens if patients are harmed? And what are the moral implications for society of these new treatments?
A. As a moral principle we believe in medical freedom: people have rights over their bodies, even at the (informed) risk of harm to themselves if no unconsenting third-parties are harmed; this is a fundamental right currently not protected effectively.
What we do differently is not changing ethical norms around safety and efficacy, we’re just changing the institutional setup. Instead of one centralized bureaucracy, like the FDA, we have regulatory pluralism that allows different providers of safety and efficacy to compete under market rules. Like under any legal system, common law in Prospera punishes malpractice, fraud, murder etc. This system will still produce safe and effective drugs, and it will still work with common sense legal notions like informed consent and liability for harm. There are regulations for medical practice, there is liability insurance and things like that. It will just do so more efficiently than the current way of doing things (unless it won’t, in which case it will change and evolve – or fail).
A direct moral benefit ´to what we do is that we increase accessibility. Typical gene therapies on the market cost $1 million dollars in the US. The gene therapy developed in Prospera costs $25,000. As to concern about whether such treatments are problematic, we do not share this perspective. We are for advancing science responsibly and we believe that both individuals and society stand to gain from improving the resiliency of the human body through advanced biotechnology.
Q. How does Prospera relate to the local Honduran population?
A. I think it's very important that our projects deliver local benefits and that they're well anchored in local communities. Because when you go to a new place, you're seen as a foreigner, and you're seen as potentially a danger or a threat. The most important thing for Prospera and Ciudad Morazan is to show we're creating jobs; we're creating employment; we're improving people's lives on the ground. Prospera is directly and indirectly employing 1,100 people. More than 2/3 of the people who are working for Prospera are Honduran. It has a lot of local service workers from the island, and it has educated Hondurans from the mainland for whom it's an alternative to going to the United States.
Q. What makes a good Prosperian citizen?
A. People in Prospera are very entrepreneurial. They're opening companies on a small scale. For example, Vehinia, who is the cook in the kitchen at Prospera, she's from the neighboring village and she started an NGO that is now funding a school where children from the local village can go to instead of a school that's 45 minutes away. There's very much a spirit of ‘let's exchange and trade with each other’. Some people might see that as a bit too commercial, but that's something about the culture that people accept and that people see as a good thing.
Q. Five years from now, if everything goes well, what do we see in Prospera?
A. I think Prospera will have at least 10,000 residents and I think Honduras hopefully will have more zones. There could be zones with a thriving industrial sector and sort of a labor-intensive economy and some that are very strong in pharmaceuticals, there could also be other zones for synthetic biology, and other zones focused on agriculture. The zones of Prospera, Ciudad Morazan and Orchidea are already showing the results we want to see, the results that we will eventually be measured by, and I'm tremendously excited about Honduras.
How to Measure Your Stress, with Dr. Rosalind Picard
Today’s podcast guest is Rosalind Picard, a researcher, inventor named on over 100 patents, entrepreneur, author, professor and engineer. When it comes to the science related to endowing computer software with emotional intelligence, she wrote the book. It’s published by MIT Press and called Affective Computing.
Dr. Picard is founder and director of the MIT Media Lab’s Affective Computing Research Group. Her research and engineering contributions have been recognized internationally. For example, she received the 2022 International Lombardy Prize for Computer Science Research, considered by many to be the Nobel prize in computer science.
Through her research and companies, Dr. Picard has developed wearable sensors, algorithms and systems for sensing, recognizing and responding to information about human emotion. Her products are focused on using fitness trackers to advance clinical quality treatments for a range of conditions.
Meanwhile, in just the past few years, numerous fitness tracking companies have released products with their own stress sensors and systems. You may have heard about Fitbit’s Stress Management Score, or Whoop’s Stress Monitor – these features and apps measure things like your heart rhythm and a certain type of invisible sweat to identify stress. They’re designed to raise awareness about forms of stress such as anxieties and anger, and suggest strategies like meditation to relax in real time when stress occurs.
But how well do these off-the-shelf gadgets work? There’s no one more knowledgeable and experienced than Rosalind Picard to explain the science behind these stress features, what they do exactly, how they might be able to help us, and their current shortcomings.
Dr. Picard is a member of the National Academy of Engineering and a Fellow of the National Academy of Inventors, and a popular speaker who’s given over a hundred invited keynote talks and a TED talk with over 2 million views. She holds a Bachelors in Electrical Engineering from Georgia Tech, and Masters and Doctorate degrees in Electrical Engineering and Computer Science from MIT. She lives in Newton, Massachusetts with her husband, where they’ve raised three sons.
In our conversation, we discuss stress scores on fitness trackers to improve well-being. She describes the difference between commercial products that might help people become more mindful of their health and products that are FDA approved and really capable of advancing the science. We also talk about several fascinating findings and concepts discovered in Dr. Picard’s lab including the multiple arousal theory, a phenomenon you’ll want to hear about. And we explore the complexity of stress, one reason it’s so tough to measure. For example, many forms of stress are actually good for us. Can fitness trackers tell the difference between stress that’s healthy and unhealthy?
Show links:
- Dr. Picard’s book, Affective Computing
- Dr. Picard’s bio
- Dr. Picard on Twitter
- Dr. Picard’s company, Empatica - https://www.empatica.com/ - The FDA-cleared Empatica Health Monitoring Platform provides accurate, continuous health insights for researchers and clinicians, collected in the real world
- Empatica Twitter
- Dr. Picard and her team have published hundreds of peer-reviewed articles across AI, Machine Learning, Affective Computing, Digital Health, and Human-computer interaction.
- Dr. Picard’s TED talk
Rosalind Picard