The Good, the Bad, and the Ugly in Personalized Medicine
Is the value of "personalized medicine" over-promised? Why is the quality of health care declining for many people despite the pace of innovation? Do patients and doctors have conflicting priorities? What is the best path forward?
"How do we generate evidence for value, which is what everyone is asking for?"
Some of the country's leading medical experts recently debated these questions at the prestigious annual Personalized Medicine Conference, held at Harvard Medical School in Boston, and LeapsMag was there to bring you the inside scoop.
Personalized Medicine: Is It Living Up to the Hype?
The buzzworthy phrase "personalized medicine" has been touted for years as the way of the future—customizing care to patients based on their predicted responses to treatments given their individual genetic profiles or other analyses. Since the initial sequencing of the human genome around fifteen years ago, the field of genomics has exploded as the costs have dramatically come down – from $2.7 billion to $1000 or less today. Given cheap access to such crucial information, the medical field has been eager to embrace an ultramodern world in which preventing illnesses is status quo, and treatments can be tailored for maximum effectiveness. But whether that world has finally arrived remains debatable.
"I've been portrayed as an advocate for genomics, because I'm excited about it," said Robert C. Green, Director of the Genomes2People Research Program at Harvard Medical School, the Broad Institute, and Brigham and Women's Hospital. He qualified his advocacy by saying that he tries to remain 'equipoised' or balanced in his opinions about the future of personalized medicine, and expressed skepticism about some aspects of its rapid commercialization.
"I have strong feelings about some of the [precision medicine] products that are rushing out to market in both the physician-mediated space and the consumer space," Green said, and challenged the value and sustainability of these products, such as their clinical utility and ability to help produce favorable health outcomes. He asked what most patients and providers want to know, which is, "What are the medical, behavioral, and economic outcomes? How do we generate evidence for value, which is what everyone is asking for?" He later questioned whether the use of 'sexy' and expensive diagnostic technologies is necessarily better than doing things the old-fashioned way. For instance, it is much easier and cheaper to ask a patient directly about their family history of disease, instead of spending thousands of dollars to obtain the same information with pricey diagnostic tests.
"Our mantra is to try to do data-driven health...to catch disease when it occurs early."
Michael Snyder, Professor & Chair of the Department of Genetics and Director of the Center for Genomics and Personalized Medicine at Stanford University, called himself more of an 'enthusiast' about precision medicine products like wearable devices that can digitally track vital signs, including heart rate and blood oxygen levels. "I'm certainly not equipoised," he said, adding, "Our mantra is to try to do data-driven health. We are using this to try to understand health and catch disease when it occurs early."
Snyder then shared his personal account about how his own wearable device alerted him to seek treatment while he was traveling in Norway. "My blood oxygen was low and my heart rate was high, so that told me something was up," he shared. After seeing a doctor, he discovered he was suffering from Lyme disease. He then shared other similar success stories about some of the patients in his department. Using wearable health sensors, he said, could significantly reduce health care costs: "$245 billion is spent every year on diabetes, and if we reduce that by ten percent we just saved $24 billion."
From left, Robert Green, Michael Snyder, Sandro Galea, and Thomas Miller.
(Courtesy Rachele Hendricks-Sturrup)
A Core Reality: Unresolved Societal Issues
Sandro Galea, Dean and Professor at Boston University's School of Public Health, coined himself as a 'skeptic' but also an 'enormous fan' of new technologies. He said, "I want to make sure that you all [the audience] have the best possible treatment for me when I get sick," but added, "In our rush and enthusiasm to embrace personalized and precision medicine approaches, we have done that at the peril of forgetting a lot of core realities."
"There's no one to pay for health care but all of us."
Galea stressed the need to first address certain difficult societal issues because failing to do so will deter precision medicine cures in the future. "Unless we pay attention to domestic violence, housing, racism, poor access to care, and poverty… we are all going to lose," he said. Then he quoted recent statistics about the country's growing gap in both health and wealth, which could potentially erode patient and provider interest in personalized medicine.
Thomas Miller, the founder and partner of a venture capital firm dedicated to advancing precision medicine, agreed with Galea and said that "there's no one to pay for health care but all of us." He recalled witnessing 'abuse' of diagnostic technologies that he had previously invested in. "They were often used as mechanisms to provide unnecessary care rather than appropriate care," he said. "The trend over my 30-year professional career has been that of sensitivity over specificity."
In other words: doctors rely too heavily on diagnostic tools that are sensitive enough to detect signs of a disease, but not accurate enough to confirm the presence of a specific disease. "You will always find that you're sick from something," Miller said. He lamented the counter-productivity and waste brought on by such 'abuse' and added, "That's money that could be used to address some of the problems that you [Galea] just talked about."
Do Patients and Providers Have Conflicting Priorities?
Distrust in the modern health care system is not new in the United States. That fact that medical errors were the third leading cause of death in 2016 may have fueled this mistrust even more. And the level of mistrust appears correlated with race; a recent survey of 118 adults between 18 to 75 years old showed that black respondents were less likely to trust their doctors than the non-Hispanic white respondents. The black respondents were also more concerned about personal privacy and potentially harmful hospital experimentation.
"The vast majority of physicians in this country are incentivized to keep you sick."
As if this context weren't troubling enough, some of the panelists suggested that health care providers and patients have misaligned goals, which may be financially driven.
For instance, Galea stated that health care is currently 'curative' even though that money is better spent on prevention versus cures. "The vast majority of physicians in this country are incentivized to keep you sick," he declared. "They are paid by sick patient visits. Hospital CEOs are paid by the number of sick people they have in their beds." He highlighted this issue as a national priority and mentioned some case studies showing that the behaviors of hospital CEOs quickly change when payment is based on the number of patients in beds versus the number of patients being kept out of the beds. Green lauded Galea's comment as "good sense."
Green also cautioned the audience about potential financial conflicts of interest held by proponents of precision medicine technologies. "Many of the people who are promoting genomics and personalized medicine are people who have financial interests in that arena," he warned. He emphasized that those who are perhaps curbing the over-enthusiasm do not have financial interests at stake.
What is the Best Path Forward for Personalized Medicine?
As useful as personalized medicine may be for selecting the best course of treatment, there is also the flip side: It can allow doctors to predict who will not respond well—and this painful reality must be acknowledged.
Miller argued, "We have a duty to call out therapies that won't work, that will not heal, that need to be avoided, and that will ultimately lead to you saying to a patient, 'There is nothing for you that will work.'"
Although that may sound harsh, it captures the essence of this emerging paradigm, which is to maximize health by using tailored methods that are based on comparative effectiveness, evidence of outcomes, and patient preferences. After all, as Miller pointed out, it wouldn't do much good to prescribe someone a regimen with little reason to think it might help.
For the hype around personalized medicine to be fully realized, Green concluded, "We have to prove to people that [the value of it] is true."
Inside the Atlantis Space Shuttle, astronauts waited for liftoff. At T-minus six seconds, the main engines ignited, rattling the capsule “like a skyscraper in an earthquake,” according to astronaut Tom Jones, describing the 1988 launch in Air & Space Magazine. Liftoff came with what felt like “a massive kick in the back,” he recalled, along with more shaking. As the rocket accelerated to three times the force of gravity on Earth, “It felt as if two of my friends were standing on my chest and wouldn’t get off!” Finally, at 25 times the speed of sound, Atlantis reached orbit. The main engines cut off, and the astronauts were weightless.
Since 1961, NASA has sent hundreds of astronauts into space while working to making their voyages safer and smoother. Yet, challenges remain. Weightlessness may look amusing when watched from Earth, but it has myriad effects on cognition, movement and other functions. When missions to space stretch to six months or longer, microgravity can harm astronauts’ health and performance, making it more difficult to operate their spacecraft.
Yesterday, NASA astronaut Frank Rubio returned to Earth after over one year, the longest single spaceflight for a U.S. astronaut. But this is just the start; longer and more complex missions into deep space loom ahead, from returning to the moon in 2025 to eventually sending humans to Mars. Understanding how spaceflight affects the body is vital to success. By studying these impacts, NASA aims to help astronauts perform in space as well as they do on Earth.
The dangers of microgravity are real
A NASA report published in 2016 details a long list of incidents and near-misses caused – at least partly – by space-induced changes in astronauts’ vision and coordination. These issues make it harder to move with precision and to judge distance and velocity.
According to the report, in 1997, a resupply ship collided with the Mir space station, possibly because a crew member bumped into the commander during the final docking maneuver. This mishap caused significant damage to the space station.
Returns to Earth suffered from problems, too. The same report notes that touchdown speeds during the first 100 space shuttle landings were “outside acceptable limits. The fastest landing on record – 224 knots (258 miles) per hour – was linked to the commander’s momentary spatial disorientation.” Earlier, each of the six Apollo crews that landed on the moon had difficulty recognizing moon landmarks and estimating distances. For example, Apollo 15 landed in an unplanned area, ultimately straddling the rim of a five-foot deep crater on the moon, harming one of its engines.
Spaceflight causes unique stresses on astronauts’ brains and central nervous systems. NASA is working to reduce these harmful effects.
Space messes up your brain
In space, astronauts face the challenges of microgravity, ionizing radiation, social isolation, high workloads, altered circadian rhythms, monotony, confined living quarters and a high-risk environment. Among these issues, microgravity is one of the most consequential in terms of physiological changes. It changes the brain’s structure and its functioning, which can hurt astronauts’ performance.
The brain shifts upwards within the skull, displacing the cerebrospinal fluid, which reduces the brain’s cushioning. Essentially, the brain becomes crowded inside the skull like a pair of too-tight shoes.
That’s partly because of how being in space alters blood flow. On Earth, gravity pulls our blood and other internal fluids toward our feet, but our circulatory valves ensure that the fluids are evenly distributed throughout the body. In space, there’s not enough gravity to pull the fluids down, and they shift up, says Rachael D. Seidler, a physiologist specializing in spaceflight at the University of Florida and principal investigator on many space-related studies. The head swells and legs appear thinner, causing what astronauts call “puffy face chicken legs.”
“The brain changes at the structural and functional level,” says Steven Jillings, equilibrium and aerospace researcher at the University of Antwerp in Belgium. “The brain shifts upwards within the skull,” displacing the cerebrospinal fluid, which reduces the brain’s cushioning. Essentially, the brain becomes crowded inside the skull like a pair of too-tight shoes. Some of the displaced cerebrospinal fluid goes into cavities within the brain, called ventricles, enlarging them. “The remaining fluids pool near the chest and heart,” explains Jillings. After 12 consecutive months in space, one astronaut had a ventricle that was 25 percent larger than before the mission.
Some changes reverse themselves while others persist for a while. An example of a longer-lasting problem is spaceflight-induced neuro-ocular syndrome, which results in near-sightedness and pressure inside the skull. A study of approximately 300 astronauts shows near-sightedness affects about 60 percent of astronauts after long missions on the International Space Station (ISS) and more than 25 percent after spaceflights of only a few weeks.
Another long-term change could be the decreased ability of cerebrospinal fluid to clear waste products from the brain, Seidler says. That’s because compressing the brain also compresses its waste-removing glymphatic pathways, resulting in inflammation, vulnerability to injuries and worsening its overall health.
The effects of long space missions were best demonstrated on astronaut twins Scott and Mark Kelly. This NASA Twins Study showed multiple, perhaps permanent, changes in Scott after his 340-day mission aboard the ISS, compared to Mark, who remained on Earth. The differences included declines in Scott’s speed, accuracy and cognitive abilities that persisted longer than six months after returning to Earth in March 2016.
By the end of 2020, Scott’s cognitive abilities improved, but structural and physiological changes to his eyes still remained, he said in a BBC interview.
“It seems clear that the upward shift of the brain and compression of the surrounding tissues with ventricular expansion might not be a good thing,” Seidler says. “But, at this point, the long-term consequences to brain health and human performance are not really known.”
NASA astronaut Kate Rubins conducts a session for the Neuromapping investigation.
Staying sharp in space
To investigate how prolonged space travel affects the brain, NASA launched a new initiative called the Complement of Integrated Protocols for Human Exploration Research (CIPHER). “CIPHER investigates how long-duration spaceflight affects both brain structure and function,” says neurobehavioral scientist Mathias Basner at the University of Pennsylvania, a principal investigator for several NASA studies. “Through it, we can find out how the brain adapts to the spaceflight environment and how certain brain regions (behave) differently after – relative to before – the mission.”
To do this, he says, “Astronauts will perform NASA’s cognition test battery before, during and after six- to 12-month missions, and will also perform the same test battery in an MRI scanner before and after the mission. We have to make sure we better understand the functional consequences of spaceflight on the human brain before we can send humans safely to the moon and, especially, to Mars.”
As we go deeper into space, astronauts cognitive and physical functions will be even more important. “A trip to Mars will take about one year…and will introduce long communication delays,” Seidler says. “If you are on that mission and have a problem, it may take eight to 10 minutes for your message to reach mission control, and another eight to 10 minutes for the response to get back to you.” In an emergency situation, that may be too late for the response to matter.
“On a mission to Mars, astronauts will be exposed to stressors for unprecedented amounts of time,” Basner says. To counter them, NASA is considering the continuous use of artificial gravity during the journey, and Seidler is studying whether artificial gravity can reduce the harmful effects of microgravity. Some scientists are looking at precision brain stimulation as a way to improve memory and reduce anxiety due to prolonged exposure to radiation in space.
To boldly go where no astronauts have gone before, they must have optimal reflexes, vision and decision-making. In the era of deep space exploration, the brain—without a doubt—is the final frontier.
Additionally, NASA is scrutinizing each aspect of the mission, including astronaut exercise, nutrition and intellectual engagement. “We need to give astronauts meaningful work. We need to stimulate their sensory, cognitive and other systems appropriately,” Basner says, especially given their extreme confinement and isolation. The scientific experiments performed on the ISS – like studying how microgravity affects the ability of tissue to regenerate is a good example.
“We need to keep them engaged socially, too,” he continues. The ISS crew, for example, regularly broadcasts from space and answers prerecorded questions from students on Earth, and can engage with social media in real time. And, despite tight quarters, NASA is ensuring the crew capsule and living quarters on the moon or Mars include private space, which is critical for good mental health.
Exploring deep space builds on a foundation that began when astronauts first left the planet. With each mission, scientists learn more about spaceflight effects on astronauts’ bodies. NASA will be using these lessons to succeed with its plans to build science stations on the moon and, eventually, Mars.
“Through internally and externally led research, investigations implemented in space and in spaceflight simulations on Earth, we are striving to reduce the likelihood and potential impacts of neurostructural changes in future, extended spaceflight,” summarizes NASA scientist Alexandra Whitmire. To boldly go where no astronauts have gone before, they must have optimal reflexes, vision and decision-making. In the era of deep space exploration, the brain—without a doubt—is the final frontier.
Swiss researchers have discovered a third type of brain cell that appears to be a hybrid of the two other primary types — and it could lead to new treatments for many brain disorders.
The challenge: Most of the cells in the brain are either neurons or glial cells. While neurons use electrical and chemical signals to send messages to one another across small gaps called synapses, glial cells exist to support and protect neurons.
Astrocytes are a type of glial cell found near synapses. This close proximity to the place where brain signals are sent and received has led researchers to suspect that astrocytes might play an active role in the transmission of information inside the brain — a.k.a. “neurotransmission” — but no one has been able to prove the theory.
A new brain cell: Researchers at the Wyss Center for Bio and Neuroengineering and the University of Lausanne believe they’ve definitively proven that some astrocytes do actively participate in neurotransmission, making them a sort of hybrid of neurons and glial cells.
According to the researchers, this third type of brain cell, which they call a “glutamatergic astrocyte,” could offer a way to treat Alzheimer’s, Parkinson’s, and other disorders of the nervous system.
“Its discovery opens up immense research prospects,” said study co-director Andrea Volterra.
The study: Neurotransmission starts with a neuron releasing a chemical called a neurotransmitter, so the first thing the researchers did in their study was look at whether astrocytes can release the main neurotransmitter used by neurons: glutamate.
By analyzing astrocytes taken from the brains of mice, they discovered that certain astrocytes in the brain’s hippocampus did include the “molecular machinery” needed to excrete glutamate. They found evidence of the same machinery when they looked at datasets of human glial cells.
Finally, to demonstrate that these hybrid cells are actually playing a role in brain signaling, the researchers suppressed their ability to secrete glutamate in the brains of mice. This caused the rodents to experience memory problems.
“Our next studies will explore the potential protective role of this type of cell against memory impairment in Alzheimer’s disease, as well as its role in other regions and pathologies than those explored here,” said Andrea Volterra, University of Lausanne.
But why? The researchers aren’t sure why the brain needs glutamatergic astrocytes when it already has neurons, but Volterra suspects the hybrid brain cells may help with the distribution of signals — a single astrocyte can be in contact with thousands of synapses.
“Often, we have neuronal information that needs to spread to larger ensembles, and neurons are not very good for the coordination of this,” researcher Ludovic Telley told New Scientist.
Looking ahead: More research is needed to see how the new brain cell functions in people, but the discovery that it plays a role in memory in mice suggests it might be a worthwhile target for Alzheimer’s disease treatments.
The researchers also found evidence during their study that the cell might play a role in brain circuits linked to seizures and voluntary movements, meaning it’s also a new lead in the hunt for better epilepsy and Parkinson’s treatments.
“Our next studies will explore the potential protective role of this type of cell against memory impairment in Alzheimer’s disease, as well as its role in other regions and pathologies than those explored here,” said Volterra.