For Tony Y., 37, healing from heartbreak is slow and incomplete. Each of several exes is associated with a cluster of sore memories. Although he loves the Blue Ridge Mountains, he can't visit because they remind him of a romantic holiday years ago.
If a new drug made rejections less painful, one expert argues, it could relieve or even prevent major depression.
Like some 30 to 40 percent of depressed patients, Tony hasn't had success with current anti-depressants. One day, psychiatrists may be able to offer him a new kind of opioid, an anti-depressant for people suffering from the cruel pain of rejection.
A Surprising Discovery
As we move through life, rejections -- bullying in school, romantic breakups, and divorces -- are powerful triggers to depressive episodes, observes David Hsu, a neuroscientist at Stony Brook University School of Medicine in Long Island, New York. If a new drug made them less painful, he argues, it could relieve or even prevent major depression.
Our bodies naturally produce opioids to soothe physical pain, and opioid drugs like morphine and oxycodone work by plugging into the same receptors in our brains. The same natural opioids may also respond to emotional hurts, and painkillers can dramatically affect mood. Today's epidemic of opioid abuse raises the question: How many lives might have been saved if we had a safe, non-addictive option for medicating emotional pain?
Already one anti-depressant, tianeptine, locks into the mu opioid receptor, the target of morphine and oxycodone. Scientists knew that tianeptine, prescribed in some countries in Europe, Asia, and Latin America, acted differently than the most common anti-depressants in use today, which affect the levels of other brain chemicals, serotonin and norepinephrine. But the discovery in 2014 that tianeptine tapped the mu receptor was a "huge surprise," says co-author Jonathan Javitch, chief of the Division of Molecular Therapeutics at Columbia University.
The news arrived when scientists' basic understanding of depression is in flux; viewed biologically, it may cover several disorders. One of them could hinge on opioids. It's possible that some people release fewer opioids naturally or that the receptors for it are less effective.
Javitch has launched a startup, Kures, to make tianeptine more effective and convenient and to find other opioid-modulators. That may seem quixotic in the midst of an opioid epidemic, but tianeptine doesn't create dependency in low, prescription doses and has been used safely around the world for decades. To identify likely patients, cofounder Andrew Kruegel is looking for ways to "segment the depressed population by measures that have to do with opioid release," he says.
Is Emotional Pain Actually "Pain"?
No one imagines that the pain from rejection or loss is the same as pain from a broken leg. Physical pain is two perceptions—a sensory perception and an "affective" one, which makes pain unpleasant.
Exploration of an overlap between physical and what research psychologists call "social pain" has heated up since the mid-2000s.
The sensory perception, processed by regions of the brain called the primary and secondary somatosensory cortices and the posterior insula, tells us whether the pain is in your arm or your leg, how strong it is and whether it is a sting, ache, or has some other quality. The affective perception, in another part of the brain called the dorsal anterior cingulate cortex and the anterior insula, tells us that we want the pain to stop, fast! When people with lesions in the latter areas experience a stimulus that ordinarily would be painful, they don't mind it.
Science now suggests that emotional pain arises in the affective brain circuits. Exploration of an overlap between physical and what research psychologists call "social pain" has heated up since the mid-2000s. Animal evidence goes back to the 1970s: babies separated from their mothers showed less distress when given morphine, and more if dosed with naloxone, the opioid antagonist.
Parents, of course, face the question of whether Baby feels alone or wet whenever she howls. And the answer is: both hurt. Being abandoned is the ultimate threat in our early life, and it makes sense that a brain system to monitor social threats would piggyback upon an existing system for pain. Piggybacking is a feature of evolution. An ancestor who felt "hurt" when threatened by rejection might learn adaptive behavior: to cooperate or run.
In 2010, a large multi-university team led by Nathan DeWall at the University of Kentucky, reported that acetaminophen (Tylenol) reduced social pain. Undergraduates took 500 mg of acetaminophen upon awakening and at bedtime every day for three weeks and reported nightly about their day using a previously-tested "Hurt Feelings Scale," rating how strongly they agreed with questions like, "Today, being teased hurt my feelings."
Over the weeks, their reports of hurt feelings steadily declined, while remaining flat in a control group that took placebos. In a second experiment, the research group showed that, compared to controls, people who had taken acetaminophen for three weeks showed less brain activity in the affective brain circuits while they experienced rejection during a virtual ball-tossing game. Later, Hsu's brain scan research supported the idea that rejection triggers the mu opioid receptor system, which normally provides pain-dampening opioids.
More evidence comes from nonhuman primates with lesions in the affective circuits: They cry less when separated from caregivers or social groups.
Heartbreak seems to lie in those regions: women with major depression are more hurt by romantic rejection than normal controls are and show more activity in those areas in brain scans, Hsu found. Also, factors that make us more vulnerable to rejection -- like low self-esteem -- are linked to more activity in the key areas, studies show.
The trait "high rejection sensitivity" increases your risk of depression more than "global neuroticism" does, Hsu observes, and predicts a poor recovery from depression. Pain sensitivity is another clue: People with a gene linked to it seem to be more hurt by social exclusion. Once you're depressed, you become more rejection-sensitive and prone to pain—a classic bad feedback loop.
"Ideally, we'd have biomarkers to distinguish when loss becomes complicated grief and then depression, and we might prevent the transition with a drug."
Helen Mayberg, a neurologist renowned for her study of brain circuits in depression, sees, as Hsu does, the possibility of preventing depressions. "Nobody would suggest we treat routine bad social pain with drugs. But it is true that in susceptible people, losing a partner, for example, can lead to a full-blown depression," says Mayberg, who is the founding director of The Center for Advanced Circuit Therapeutics at Mount Sinai's Icahn School of Medicine in New York City. "Ideally, we'd have biomarkers to distinguish when loss becomes complicated grief and then depression, and we might prevent the transition with a drug. It would be like taking medication when you feel the warning symptoms of a headache to prevent a full-blown migraine."
A Way Out of the Opioid Crisis?
The exploration of social pain should lead us to a deeper understanding of pain, beyond the sharp distinctions between "physical" and "psychological." Finding our way out of the current crisis may require that deeper understanding. About half of the people with opioid prescriptions have mental health disorders. "I expect there are a lot of people using street opioids—heroin or prescriptions purchased from others--to self-medicate psychological pain," Kreugel says.
What we may need, he suggests, is "a new paradigm for using opioids in psychiatry: low, sub-analgesic, sub-euphoric dosing." But so far it hasn't been easy. Investors don't flock to fund psychiatric drugs and in 2018, the word opioid is poison.
As for Tony Y., he's struggled for three years to recover from his most serious relationship. "Driving around highways looking at exit signs toward places we visited together sometimes fills me with unbearable anguish," he admits. "And because we used to do so much bird watching together, sometimes a mere glimpse of a random bird sets me off." He perks up at the idea of a heartbreak drug. "If the side effects didn't seem bad, I would consider it, absolutely."
In December 1958, on a vacation with his wife in Kenya, a 28-year-old British tea broker named Robin Cavendish became suddenly ill. Neither he nor his wife Diana knew it at the time, but Robin's illness would change the course of medical history forever.
Robin was rushed to a nearby hospital in Kenya where the medical staff delivered the crushing news: Robin had contracted polio, and the paralysis creeping up his body was almost certainly permanent. The doctors placed Robin on a ventilator through a tracheotomy in his neck, as the paralysis from his polio infection had rendered him unable to breathe on his own – and going off the average life expectancy at the time, they gave him only three months to live. Robin and Diana (who was pregnant at the time with their first child, Jonathan) flew back to England so he could be admitted to a hospital. They mentally prepared to wait out Robin's final days.
But Robin did something unexpected when he returned to the UK – just one of many things that would astonish doctors over the next several years: He survived. Diana gave birth to Jonathan in February 1959 and continued to visit Robin regularly in the hospital with the baby. Despite doctors warning that he would soon succumb to his illness, Robin kept living.
After a year in the hospital, Diana suggested something radical: She wanted Robin to leave the hospital and live at home in South Oxfordshire for as long as he possibly could, with her as his nurse. At the time, this suggestion was unheard of. People like Robin who depended on machinery to keep them breathing had only ever lived inside hospital walls, as the prevailing belief was that the machinery needed to keep them alive was too complicated for laypeople to operate. But Diana and Robin were up for the challenges – and the risks. Because his ventilator ran on electricity, if the house were to unexpectedly lose power, Diana would either need to restore power quickly or hand-pump air into his lungs to keep him alive.
Robin's wheelchair was not only the first of its kind; it became the model for the respiratory wheelchairs that people still use today.
In an interview as an adult, Jonathan Cavendish reflected on his parents' decision to live outside the hospital on a ventilator: "My father's mantra was quality of life," he explained. "He could have stayed in the hospital, but he didn't think that was as good of a life as he could manage. He would rather be two minutes away from death and living a full life."
After a few years of living at home, however, Robin became tired of being confined to his bed. He longed to sit outside, to visit friends, to travel – but had no way of doing so without his ventilator. So together with his friend Teddy Hall, a professor and engineer at Oxford University, the two collaborated in 1962 to create an entirely new invention: a battery-operated wheelchair prototype with a ventilator built in. With this, Robin could now venture outside the house – and soon the Cavendish family became famous for taking vacations. It was something that, by all accounts, had never been done before by someone who was ventilator-dependent. Robin and Hall also designed a van so that the wheelchair could be plugged in and powered during travel. Jonathan Cavendish later recalled a particular family vacation that nearly ended in disaster when the van broke down outside of Barcelona, Spain:
"My poor old uncle [plugged] my father's chair into the wrong socket," Cavendish later recalled, causing the electricity to short. "There was fire and smoke, and both the van and the chair ground to a halt." Johnathan, who was eight or nine at the time, his mother, and his uncle took turns hand-pumping Robin's ventilator by the roadside for the next thirty-six hours, waiting for Professor Hall to arrive in town and repair the van. Rather than being panicked, the Cavendishes managed to turn the vigil into a party. Townspeople came to greet them, bringing food and music, and a local priest even stopped by to give his blessing.
Robin had become a pioneer, showing the world that a person with severe disabilities could still have mobility, access, and a fuller quality of life than anyone had imagined. His mission, along with Hall's, then became gifting this independence to others like himself. Robin and Hall raised money – first from the Ernest Kleinwort Charitable Trust, and then from the British Department of Health – to fund more ventilator chairs, which were then manufactured by Hall's company, Littlemore Scientific Engineering, and given to fellow patients who wanted to live full lives at home. Robin and Hall used themselves as guinea pigs, testing out different models of the chairs and collaborating with scientists to create other devices for those with disabilities. One invention, called the Possum, allowed paraplegics to control things like the telephone and television set with just a nod of the head. Robin's wheelchair was not only the first of its kind; it became the model for the respiratory wheelchairs that people still use today.
Robin went on to enjoy a long and happy life with his family at their house in South Oxfordshire, surrounded by friends who would later attest to his "down-to-earth" personality, his sense of humor, and his "irresistible" charm. When he died peacefully at his home in 1994 at age 64, he was considered the world's oldest-living person who used a ventilator outside the hospital – breaking yet another barrier for what medical science thought was possible.
Sarah Watts is a health and science writer based in Chicago. Follow her on Twitter at @swattswrites.
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."