Is There a Blind Spot in the Oversight of Human Subject Research?
A scientist examining samples.
Human experimentation has come a long way since congressional hearings in the 1970s exposed patterns of abuse. Where yesterday's patients were protected only by the good conscience of physician-researchers, today's patients are spirited past hazards through an elaborate system of oversight and informed consent. Yet in many ways, the project of grounding human research on ethical foundations remains incomplete.
As human research has become a mainstay of career and commercial advancement among academics, research centers, and industry, new threats to research integrity have emerged.
To be sure, much of the medical research we do meets exceedingly high standards. Progress in cancer immunotherapy, or infectious disease, reflects the best of what can be accomplished when medical scientists and patients collaborate productively. And abuses of the earlier part of the 20th century--like those perpetrated by the U.S. Public Health Service in Guatemala--are for the history books.
Yet as human research has become a mainstay of career and commercial advancement among academics, research centers, and industry, new threats to research integrity have emerged. Many flourish in the blind spot of current oversight systems.
Take, for example, the tendency to publish only "positive" findings ("publication bias"). When patients participate in studies, they are told that their contributions will promote medical discovery. That can't happen if results of experiments never get beyond the hard drives of researchers. While researchers are often eager to publish trials showing a drug works, according to a study my own team conducted, fewer than 4 in 10 trials of drugs that never receive FDA approval get published. This tendency- which occurs in academia as well as industry- deprives other scientists of opportunities to build on these failures and make good on the sacrifice of patients. It also means the trials may be inadvertently repeated by other researchers, subjecting more patients to risks.
On the other hand, many clinical trials test treatments that have already been proven effective beyond a shadow of doubt. Consider the drug aprotinin, used for the management of bleeding during surgery. An analysis in 2005 showed that, not long after the drug was proven effective, researchers launched dozens of additional placebo-controlled trials. These redundant trials are far in excess of what regulators required for drug approval, and deprived patients in placebo arms of a proven effective therapy. Whether because of an oversight or deliberately (does it matter?), researchers conducting these trials often failed in publications to describe previous evidence of efficacy. What's the point of running a trial if no one reads the results?
It is surprisingly easy for companies to hijack research to market their treatments.
At the other extreme are trials that are little more than shots in the dark. In one case, patients with spinal cord injury were enrolled in a safety trial testing a cell-based regenerative medicine treatment. After the trial stopped (results were negative), laboratory scientists revealed that the cells had been shown ineffective in animal experiments. Though this information had been available to the company and FDA, researchers pursued the trial anyway.
It is surprisingly easy for companies to hijack research to market their treatments. One way this happens is through "seeding trials"- studies that are designed not to address a research question, but instead to habituate doctors to using a new drug and to generate publications that serve as advertisements. Such trials flood the medical literature with findings that are unreliable because studies are small and not well designed. They also use the prestige of science to pursue goals that are purely commercial. Yet because they harm science- not patients (many such studies are minimally risky because all patients receive proven effective medications)- ethics committees rarely block them.
Closely related is the phenomenon of small uninformative trials. After drugs get approved by the FDA, companies often launch dozens of small trials in new diseases other than the one the drug was approved to treat. Because these studies are small, they often overestimate efficacy. Indeed, the way trials are often set up, if a company tests an ineffective drug in 40 different studies, one will typically produce a false positive by chance alone. Because companies are free to run as many trials as they like and to circulate "positive" results, they have incentives to run lots of small trials that don't provide a definitive test of their drug's efficacy.
Universities, funding bodies, and companies should be scored by a neutral third-party based on the impact of their trials -- like Moody's for credit ratings.
Don't think public agencies are much better. Funders like the National Institutes of Health secure their appropriations by gratifying Congress. This means that NIH gets more by spreading its funding among small studies in different Congressional districts than by concentrating budgets among a few research institutions pursuing large trials. The result is that some NIH-funded clinical trials are not especially equipped to inform medical practice.
It's tempting to think that FDA, medical journals, ethics committees, and funding agencies can fix these problems. However, these practices continue in part because FDA, ethics committees, and researchers often do not see what is at stake for patients by acquiescing to low scientific standards. This behavior dishonors the patients who volunteer for research, and also threatens the welfare of downstream patients, whose care will be determined by the output of research.
To fix this, deficiencies in study design and reporting need to be rendered visible. Universities, funding bodies, and companies should be scored by a neutral third-party based on the impact of their trials, or the extent to which their trials are published in full -- like Moody's for credit ratings, or the Kelley Blue Book for cars. This system of accountability would allow everyone to see which institutions make the most of the contributions of research subjects. It could also harness the competitive instincts of institutions to improve research quality.
Another step would be for researchers to level with patients when they enroll in studies. Patients who agree to research are usually offered bromides about how their participation may help future patients. However, not all studies are created equal with respect to merit. Patients have a right to know when they are entering studies that are unlikely to have a meaningful impact on medicine.
Ethics committees and drug regulators have done a good job protecting research volunteers from unchecked scientific ambition. However, today's research is plagued by studies that have poor scientific credentials. Such studies free-ride on the well-earned reputation of serious medical science. They also potentially distort the evidence available to physicians and healthcare systems. Regulators, academic medical centers, and others should establish policies that better protect human research volunteers by protecting the quality of the research itself.
In this week's Friday Five, an old diabetes drug finds an exciting new purpose. Plus, how to make the cities of the future less toxic, making old mice younger with EVs, a new reason for mysterious stillbirths - and much more.
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Here is the promising research covered in this week's Friday Five:
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- How to make cities of the future less noisy
- An old diabetes drug could have a new purpose: treating an irregular heartbeat
- A new reason for mysterious stillbirths
- Making old mice younger with EVs
- No pain - or mucus - no gain
And an honorable mention this week: How treatments for depression can change the structure of the brain
Researchers at Stanford have found that the virus that causes Covid-19 can infect fat cells, which could help explain why obesity is linked to worse outcomes for those who catch Covid-19.
Obesity is a risk factor for worse outcomes for a variety of medical conditions ranging from cancer to Covid-19. Most experts attribute it simply to underlying low-grade inflammation and added weight that make breathing more difficult.
Now researchers have found a more direct reason: SARS-CoV-2, the virus that causes Covid-19, can infect adipocytes, more commonly known as fat cells, and macrophages, immune cells that are part of the broader matrix of cells that support fat tissue. Stanford University researchers Catherine Blish and Tracey McLaughlin are senior authors of the study.
Most of us think of fat as the spare tire that can accumulate around the middle as we age, but fat also is present closer to most internal organs. McLaughlin's research has focused on epicardial fat, “which sits right on top of the heart with no physical barrier at all,” she says. So if that fat got infected and inflamed, it might directly affect the heart.” That could help explain cardiovascular problems associated with Covid-19 infections.
Looking at tissue taken from autopsy, there was evidence of SARS-CoV-2 virus inside the fat cells as well as surrounding inflammation. In fat cells and immune cells harvested from health humans, infection in the laboratory drove "an inflammatory response, particularly in the macrophages…They secreted proteins that are typically seen in a cytokine storm” where the immune response runs amok with potential life-threatening consequences. This suggests to McLaughlin “that there could be a regional and even a systemic inflammatory response following infection in fat.”
It is easy to see how the airborne SARS-CoV-2 virus infects the nose and lungs, but how does it get into fat tissue? That is a mystery and the source of ample speculation.
The macrophages studied by McLaughlin and Blish were spewing out inflammatory proteins, While the the virus within them was replicating, the new viral particles were not able to replicate within those cells. It was a different story in the fat cells. “When [the virus] gets into the fat cells, it not only replicates, it's a productive infection, which means the resulting viral particles can infect another cell,” including microphages, McLaughlin explains. It seems to be a symbiotic tango of the virus between the two cell types that keeps the cycle going.
It is easy to see how the airborne SARS-CoV-2 virus infects the nose and lungs, but how does it get into fat tissue? That is a mystery and the source of ample speculation.
Macrophages are mobile; they engulf and carry invading pathogens to lymphoid tissue in the lymph nodes, tonsils and elsewhere in the body to alert T cells of the immune system to the pathogen. Perhaps some of them also carry the virus through the bloodstream to more distant tissue.
ACE2 receptors are the means by which SARS-CoV-2 latches on to and enters most cells. They are not thought to be common on fat cells, so initially most researchers thought it unlikely they would become infected.
However, while some cell receptors always sit on the surface of the cell, other receptors are expressed on the surface only under certain conditions. Philipp Scherer, a professor of internal medicine and director of the Touchstone Diabetes Center at the University of Texas Southwestern Medical Center, suggests that, in people who have obesity, “There might be higher levels of dysfunctional [fat cells] that facilitate entry of the virus,” either through transiently expressed ACE2 or other receptors. Inflammatory proteins generated by macrophages might contribute to this process.
Another hypothesis is that viral RNA might be smuggled into fat cells as cargo in small bits of material called extracellular vesicles, or EVs, that can travel between cells. Other researchers have shown that when EVs express ACE2 receptors, they can act as decoys for SARS-CoV-2, where the virus binds to them rather than a cell. These scientists are working to create drugs that mimic this decoy effect as an approach to therapy.
Do fat cells play a role in Long Covid? “Fat cells are a great place to hide. You have all the energy you need and fat cells turn over very slowly; they have a half-life of ten years,” says Scherer. Observational studies suggest that acute Covid-19 can trigger the onset of diabetes especially in people who are overweight, and that patients taking medicines to regulate their diabetes “were actually quite protective” against acute Covid-19. Scherer has funding to study the risks and benefits of those drugs in animal models of Long Covid.
McLaughlin says there are two areas of potential concern with fat tissue and Long Covid. One is that this tissue might serve as a “big reservoir where the virus continues to replicate and is sent out” to other parts of the body. The second is that inflammation due to infected fat cells and macrophages can result in fibrosis or scar tissue forming around organs, inhibiting their function. Once scar tissue forms, the tissue damage becomes more difficult to repair.
Current Covid-19 treatments work by stopping the virus from entering cells through the ACE2 receptor, so they likely would have no effect on virus that uses a different mechanism. That means another approach will have to be developed to complement the treatments we already have. So the best advice McLaughlin can offer today is to keep current on vaccinations and boosters and lose weight to reduce the risk associated with obesity.