Monday, December 14, 2015

WHO says bacon causes cancer?

by Neha Pancholi

Note: Here at the PSPG blog, we like to feature writing from anyone in the Penn community interested in the science policy process or science for general interest. This is the 1st in a series of posts from new authors. Interested is writing for the blog? Contact us!

The daily meat consumption in the United States exceeds that of almost every other country1. While the majority of meat consumed in the United States is red meat2, the consumption of certain red meats has decreased over the past few decades due to associated health concerns, such as heart disease and diabetes1,2. In October, the World Health Organization (WHO) highlighted another potential health concern for red meat: cancer.

The announcement concerned both red and processed meat. Red meat is defined as unprocessed muscle meat from mammals, such as beef and pork3. Processed meat– generally red meat –has been altered to improve flavor through processes such as curing or smoking3. Examples of processed meat include bacon and sausage. The WHO confirmed that processed meat causes cancer and that red meat probably causes cancer. Given the prevalence of meat in the American diet, it was not surprising that the announcement dominated headlines and social media. So how exactly did the WHO decide that processed meat causes cancer?

The announcement by the WHO followed a report from the International Agency for Research on Cancer (IARC), which is responsible for identifying and assessing suspected causes of cancer. The IARC evaluates the typical level of exposure to a suspected agent, results from existing studies, and the mechanism by which the agent could cause cancer.

After a review of existing literature, the IARC classifies the strength of scientific evidence linking the suspected cancer-causing agent to cancer. Importantly, the IARC determines only whether there is sufficient evidence that something can cause cancer. The IARC does not evaluate risk, meaning that it does not evaluate how carcinogenic something is. The IARC classifies the suspected carcinogen into one of the following categories4:
  • Group 1 – There is convincing evidence linking the agent to cancer in humans. The agent is deemed carcinogenic.
  • Group 2A – There is sufficient evidence of cancer in animal models, and there is a positive association observed in humans. However, the evidence in humans does not exclude the possibility of bias, chance, or confounding variables. The agent is deemed as a probable carcinogen.
  • Group 2B – There is a positive association in humans, but the possibility of bias, chance, or confounding variables cannot be excluded. There is inadequate evidence in animal models.
  • This category is also used when there is sufficient evidence of cancer in animal models, but there is not an association observed in humans. The agent is a possible carcinogen.
  • Group 3 – There is inadequate evidence in humans and animals. The agent cannot be classified as carcinogenic or not carcinogenic.
  • Group 4 – There is sufficient evidence to conclude that the agent is not carcinogenic in humans or in animals.
The IARC reviewed over 800 studies that examined the correlation between consumption of processed or red meat and cancer occurrence in humans. These types of studies, which examine patterns of disease in different populations, are called epidemiological studies. The studies included observations from all over the world and included diverse ethnicities and diets. The greatest weight was given to studies that followed the same group of people over time and had an appropriate control group. Most of the available data examined the association between meat consumption and colorectal cancer, but some studies also assessed the effect on stomach, pancreatic, and prostate cancer. The majority of studies showed a higher occurrence of colorectal cancer in people whose diets included high consumption of red or processed meat compared to those who have low consumption. By comparing results from several studies, the IARC determined that for every 100 grams of red meat consumed per day, there is a 17% increase in cancer occurrence. For every 50 grams of processed meat eaten per day, there is an 18% increase. The average red meat consumption for those who eat it is 50-100 grams per day.3

The IARC also reviewed studies that examined how meat could cause cancer. They found strong evidence that consumption of red or processed meat leads to the formation of known carcinogens called N-nitroso compounds in the colon. It is also known that cooked meat contains two types of compounds that are known to damage DNA, which can lead to cancer. However, there is not a direct link between eating meat containing these compounds and DNA damage in the body.3

Based on the strong evidence demonstrating a positive association with consumption of processed meat and colorectal cancer, the IARC classified processed meat as a Group 1 agent3. This means that there is sufficient evidence that consumption of processed meat causes cancer.

There was a positive association between consumption of red meat and colorectal cancer in several epidemiological studies. However, the possibility of chance or bias could not be excluded from these studies. Furthermore, the best-designed epidemiological studies did not show any association between red meat consumption and cancer. Despite the limited epidemiological evidence, there was strong mechanistic evidence demonstrating that red meat consumption results in the production of known carcinogens in the colon. Therefore, red meat was classified as a probable carcinogen (Group 2A)3.

It will be interesting to see how the WHO announcement affects red meat consumption in the United States and worldwide. But before swearing off processed and red meat forever, there are a few things to consider.

First, it is important to bear in mind that agents classified within the same group have varying carcinogenic potential. Processed meat was classified as a Group 1 agent, which is the same classification for tobacco smoke. However, estimates by the Global Burden of Disease Project attribute approximately 34,000 cancer deaths per year to consumption of processed meat5. In contrast, one million cancer deaths per year are due to tobacco smoke5. While the evidence linking processed meat to cancer is strong, the risk of cancer due to processed meat consumption appears to be much lower than other known carcinogens. Second, the IARC did not evaluate studies that compared vegetarian or poultry diets to red meat consumption5. Therefore, it is unknown whether vegetarian or poultry diets are associated with fewer cases of cancer. Finally, red meat is high in protein, iron, zinc, and vitamin B123. Thus, while high red meat consumption is associated with some diseases, there are also several health benefits of consuming red meat in moderation. Ultimately, it will be important to balance the risks and benefits of processed and red meat consumption.

3Bouvard et al. Carcinogenicity of consumption of red and processed meat. The Lancet Oncology, 2015. 16(16): 1599-1600.

Thursday, December 3, 2015

Ready to Adapt: Experts Discuss Philadelphia Epidemic Preparedness

by Jamie DeNizio and Hannah Shoenhard

In early November, public health experts from a variety of organizations gathered on Penn’s campus to discuss Philadelphia’s communication strategies and preparation efforts in the event of an epidemic outbreak. In light of recent crises, such as H1N1 and Ebola in the US, AAAS Emerging Leaders in Science and Society (ELISS) fellows and the Penn Science Policy Group (PSPG) hosted local experts at both a public panel discussion and a focus group meeting to understand the systems currently in place and develop ideas about what more can be done.
Are we prepared?: Communication with the public
Dr. Max King, moderator of the public forum, set the tone for both events with a Benjamin Franklin quote: “By failing to prepare, you are preparing to fail.” Measures taken before a crisis begins can make or break the success of a public health response. In particular, in the age of the sensationalized, 24-hour news cycle, the only way for public health professionals to get the correct message to the public is to establish themselves as trustworthy sources of information in the community ahead of time.
For reaching the general population, the advent of social media has been game-changing. As an example, James Garrow, Director of Digital Public Health for the Philadelphia Department of Public Health, described Philadelphia’s use of its Facebook page to rapidly disseminate information during the H1N1 flu outbreak. The city was able to provide detailed information while interacting with and answering questions directly from members of the public in real time, a considerable advantage over traditional TV or print news.

However, Garrow was quick to note that “mass media still draws a ton of eyeballs,” and that any public health outreach program would be remiss to neglect traditional media such as TV, radio, and newspapers. At this point, social media is a complement to, but not a replacement for, other forms of media engagement.
Furthermore, those typically at greater risk during an epidemic are often unable to interact with social media channels due to economic disadvantage, age, or a language barrier. In Philadelphia, 21.5% of the population speaks a language other than English at home. Meanwhile, 12.5% of the population is over the age of 65 (U.S. Census Bureau). The focus group meeting specifically discussed how to reach these underserved groups. Some suggestions included having “block captains” or registries. “Block captains” would be Philadelphia citizens from a particular block or neighborhood that would be responsible for communicating important information to residents in their designated section. In addition to these methods of monitoring individuals, there was general agreement that there is a need for translation-friendly, culturally-relevant public health messages.

For example, during the open forum, Giang T. Nguyen, leader of the Penn Asian Health Initiative and Senior Fellow of the Penn Center for Public Health Initiatives, emphasized the importance of building ties with “ethnic media”: small publications or radio channels that primarily cater to immigrant communities in their own languages. He noted that, in the past, lack of direct contact between government public health organizations and non-English-speaking communities has led to the spread of misinformation in these communities.

On the other hand, Philadelphia has also successfully engaged immigrant communities in the recent past. For example, Garrow pointed to Philadelphia’s outreach in the Liberian immigrant community during the Ebola outbreak as a success story. When the outbreak began, the health department had already built strong ties with the Liberian community, to the point where the community actively asked the health department to hold a town hall meeting, rather than the reverse. This anecdote demonstrates the importance of establishing trust and building ties before a crisis emerges.
With regards to both general and community-targeted communication, the experts agreed that lack of funding is a major barrier to solving current problems. At the expert meeting, it was suggested that communication-specific grants, rather than larger grants with a certain percentage allotted for communication, might be one way of ameliorating this problem.
Are we prepared?: Communication between health organizations

The need for established communications networks extends beyond those for communicating directly with individuals. It is crucial for the local health department and healthcare system to have a strong relationship. Here in Philadelphia, the health department has a longstanding relationship with Penn Medicine, as well as other universities and major employers. In case of an emergency, these institutions are prepared to distribute vaccines or other medicines. Furthermore, mechanisms for distribution of vaccines already in place are “road-tested” every year during flu season. As an example, Penn vaccinated 2,500 students and faculty for the flu in eight hours during a recent vaccination drive, allowing personnel to sharpen their skills and identify any areas that need improvement.

In addition to the strong connections between major Philadelphia institutions, there is also a need for smaller health centers and community centers to be kept in the loop. These small providers serve as trusted intermediaries between large public health organizations and the public. According to the experts, these relationships are already in place. For example, during the recent Ebola crisis, the CDC set up a hotline for practitioners to call if one of their patients returned from an Ebola-stricken country with worrying symptoms. “You can’t expect everyone in the entire health system to know all they need to know [about treating a potential Ebola case],” said Nguyen, “but you can at least ensure that every practice manager and medical director knows the phone number to call.”

Can we adapt?
Ultimately, no crisis situation is fully predictable. Therefore, what matters most for responders is not merely having the proper protocols, resources, and avenues of communication in place, but also the ability to adjust their reaction to a crisis situation as it evolves. As Penn behavioral economics and health policy expert Mitesh Patel pointed out at the end of the open forum, “It’s not are we ready?, it’s are we ready to adapt?
The topic of adaptability was also heavily discussed at the focus group meeting. A lack of a central communication source was identified as a potential barrier to adaptability. So was a slow response from agencies further up the chain of command, such as the CDC. However, experts also disagreed about the precise degree of control the CDC should have at a local level. For example, representatives from local government agencies, which are more directly accountable to the CDC, expressed a desire for the CDC to proactively implement strategies, instead of attempting to direct the local response once it has already begun. Many physicians and hospital representatives, on the other hand, were of the opinion that plans formulated by the people closest to the crisis may be superior due to their situational specificity and lack of red tape. Despite this point of contention, experts agreed that there is a need for some consensus and coordination between hospitals in a particular region on how to respond to a large-scale health event.

One gap in Philadelphia’s preparedness identified by the experts in the focus group is its ability to case manage novel diseases—a challenge, since often the transmission route of novel diseases is not known. Some experts in the meeting also expressed doubt that Philadelphia is prepared for a direct biological attack. However, numerous epidemic-response frameworks already in place could potentially be repurposed for novel or deliberately-spread pathogens. In these cases, even more so than in “typical” epidemic situations, the experts identified adaptability as a key factor for success.

At the end of the open forum, the panelists affirmed the belief that Philadelphia is as prepared as it can be for an infectious disease crisis.  Furthermore, it seemed they had also moved the opinions of the event’s attendees: before the forum, attendees rated Philadelphia’s readiness at an average of 3.1 on a 6-point scale (with 0 being “not at all ready” and 6 being “completely ready”), while afterwards, the same attendees rated Philadelphia’s readiness at an average of 3.9 on the same scale (p=0.07, paired t-test).

Sunday, November 22, 2015

Reminder: Science does not happen in a vacuum

by Chris Yarosh

It is very easy to become wrapped up in day-to-day scientific life. There is always another experiment to do, or a paper to read, or a grant to submit. This result leads to that hypothesis, and that hypothesis needs to be tested, revised, re-tested, etc. Scientists literally study the inner workings of life, matter and the universe itself, yet science often seems set apart from other worldly concerns.

But it’s not.

The terrorist attacks in Paris and Beirut and the ongoing Syrian refugee crisis have drawn the world’s attention, and rightfully so. These are genuine catastrophes, and it is difficult to imagine the suffering of those who must face the aftermath of these bouts of shocking violence.

At the same time, 80 world leaders are preparing to gather in freshly scarred Paris for another round of global climate talks. In a perfect world, these talks would focus only on the sound science and overwhelming consensus supporting action on climate change, and they would lead to an agreement that sets us on a path toward healing our shared home.

But this is not a perfect world.

In addition to the ongoing political struggle and general inertia surrounding climate change, we now must throw the fallout from the Paris attacks into the mix. Because of this, the event schedule will be limited to core discussions, which will deprive some people of their chance to demonstrate and make their voices heard on a large stage. This is a shame, but at least the meeting will go on. If the situation is as dire as many scientists and policy experts say it is, this meeting may be our last chance to align the world’s priorities and roll back the damage being caused to our planet. It was never going to be easy, and the fearful specter of terrorism—and the attention and resources devoted to the fight against it— does nothing to improve the situation.

This is a direct example of world events driving science and science policy, but possible indirect effects abound as well. It is not outside the realm of possibility that political disagreement over refugee relocation may lead to budget fights or government shutdown, both of which could seriously derail research in the U.S. With Election 2016 rapidly approaching, it is also possible that events abroad can drive voter preferences at home, with unforeseen impacts on how research is funded, conducted, and disseminated.

What does this mean for science and science policy?

For one, events like this remind us once again that scientists must stay informed and be ready to adapt as sentiments and attention shift in real time. Climate change and terrorism may not have seemed linked until now (though there is good reason to think that this connection runs deep), but the dramatic juxtaposition of both in Paris changes that. Scientists can offer our voices to the discussion, but it is vital that we keep abreast of the shifting political landscapes that influence the conduct and application of science. Keeping this birds-eye view is critical, because while these terrorist attacks certainly demand attention and action, they do nothing to change the urgent need for action on the climate, on health, and on a whole host of issues that require scientific expertise.

While staying current and engaging in policymaking is always a good thing for science (feel free to contact your representatives at any time), situations like the Syrian refugee crisis offer a more unique chance to lend a hand. Science is one of humanity’s greatest shared endeavors, an approach to understanding the world that capitalizes on the innate curiosity that all people share. This shared interest has always extended to displaced peoples, with the resulting collaborations providing a silver lining to the negative events that precipitated their migrations. Where feasible, it would be wise for universities across the globe to welcome Syrians with scientific backgrounds; doing so would provide continuity and support for the displaced while preventing a loss of human capital. Efforts to this effect are currently underway in Europe, though it is unclear how long these programs can survive the tension surrounding that continent.

For good and ill, world events have always shaped science. The tragedies in France, Syria, and elsewhere have incurred great human costs, and they will serve as a test of our shared humanity. As practitioners of one of our great shared enterprises, scientists have a uniquely privileged place in society, and we should use our station to help people everywhere in any way possible.

Wednesday, November 4, 2015

Communicating about an Epidemic in the Digital Age - Live Stream of Forum

To watch this event in real time, please follow this link (from 530 - 7pm, 11/4)

How prepared are Philadelphia’s institutions to communicate with the public in the event of a future epidemic? What specific challenges were successfully or unsuccessfully addressed during the Ebola crisis that could provide learning points going forward? Are there successful models or case studies for handling communication during epidemics that are worth emulating?

These questions will be up for debate on Wednesday at the University of Pennsylvania in a forum open to the public. The event will be held in the Penn bookstore (3601 Walnut St.) upstairs meeting room from 5:30 to 7 p.m. on Wednesday, November 4.

To learn more about this event, please read our preview article.

Tuesday, November 3, 2015

New funding mechanism aims to bring balance to the biomedical research (work)force

by Chris Yarosh

This past March, the National Cancer Institute (NCI) announced a new funding mechanism designed to stabilize the biomedical research enterprise by creating new career paths for PhD-level scientists. That mechanism, called the NCI Research Specialist Award (R50), is now live. Applications (of which there will likely be many) for the R50 will be accepted beginning in January, with the first crop of directly-funded Research Specialists starting in October 2016. More details about the grant can be found in the newly released FOA.

Why is this a big deal? In recent years, there have been increased calls for reform of the biomedical enterprise. More people than ever hold PhDs, and professor positions (the traditional career goal of doctorate holders) are scarce. This leaves many young researchers trapped somewhere in the middle in postdoctoral positions, something we've talked about  before on this blog. These positions are still considered to be training positions, and without professor openings (or funding for independent labs), these scientists often seek industry positions or leave the bench altogether in lieu of finding academic employment.

On the flip side, modern academic labs are highly dependent on a constant stream of graduate students and postdocs to do the lion’s share of the research funded by principal investigator-level grants (R01s). This creates a situation where entire labs can turn over in relatively short periods of time, possibly diminishing the impact of crucial research programs.

But what if there was another way? That, in a nutshell, is the aim of the R50. By funding the salaries (but not the research costs) of PhD-level researchers, the R50 seeks to create opportunities for scientists to join established research programs or core facilities without having to obtain larger grants or academic appointments. This attempts to kill two birds with one stone: more jobs for PhDs, less turnover in labs already funded by other NCI grants.

This approach is not all roses, however. For one, this doesn’t change the fact that research funding has been flat or worse in recent years. Even with more stable staffing, the amount of research being completed will continue to atrophy. Moreover, the money for future R50s will need to come from somewhere, and it is possible that this will put additional strain on the NCI’s budget if overall R&D spending is not increased soon. Lastly, there are some concerns about how the R50 will work in practice. For example, Research Specialists will be able to move to other labs with NCI approval, but how will this actually play out? Will R50s really be pegged to their recipients, or will there be an implicit understanding that they are tied to the supporting labs/institutions?

It should be noted that this is only a trial period, and that full evaluation of the program will not be possible until awards are actually made. Still, this seems like a positive response to the forces currently influencing the biomedical research enterprise, and it will be interesting to see if and when the other NIH institutes give something like this a shot.

Monday, November 2, 2015

Communicating about an Epidemic in the Digital Age

**Link for live streaming of this event can be found here**

by Hannah Shoenhard, Jamie DeNizio, and Michael Allegrezza

Craig Spencer, a New York City doctor, tested positive for Ebola on October 23. The story broke online the same day, and by the next morning, tabloids were plastered with images of masked and gowned health workers with headlines such as Bungle Fever and Ebola! Late-night comedy, Twitter, local news: the story was inescapable, the hysteria palpable. All in all, only eleven Ebola patients were treated on U.S. soil. But the media’s reaction affected the lives of anyone who watched television or had an internet connection.

The Ebola epidemic in Africa has died down. Liberia is Ebola-free, while Sierra Leone and Guinea continue to report cases in the low single digits per week. Most promisingly, a new vaccine has been shown to be highly effective in a clinical trial. Given the vaccine, it seems that the likelihood of future epidemics on the scale of the one in 2014 is low. But especially during the early days of the epidemic, miscommunication and mistrust of international public health workers slowed the medical response and exacerbated the epidemic. And, as the reaction to the New York City case shows us, this problem is not unique to West African countries.

Even if the threat from Ebola in particular is under control, infectious disease is endemic to civilization. Knowing that new epidemic threats can emerge at any time, important questions need to be considered. 

How prepared are Philadelphia’s institutions to communicate with the public in the event of a future epidemic? What specific challenges were successfully or unsuccessfully addressed during the Ebola crisis that could provide learning points going forward? Are there successful models or case studies for handling communication during epidemics that are worth emulating?

These questions will be up for debate on Wednesday at the University of Pennsylvania in a forum open to the public. The event will be held in the Penn bookstore (3601 Walnut St.) upstairs meeting room from 5:30 to 7 p.m. on Wednesday, November 4.

The event is hosted by two graduate student groups at Penn, the Emerging Leaders in Science and Society (ELISS) Fellows and the Penn Science Policy Group with the goal of fostering collaborative ideas to develop effective channels to manage trust, fear, and accurate communication during potential future epidemics.

On the panel for the forum will be three innovators in communicating public health issues, Dr. Mitesh Patel, MD, MBA, MS, James Garrow, MPH, and Dr. Giang T. Nguyen, MD, MPH, MSCE. Moderating the discussion will be Dr. Max King, Ph.D., Associate Vice Provost for Health and Academic Services at Penn.

Community members are encouraged to attend the forum with questions and comments. People can also watch a live stream of the event (check our twitter page for the link) and submit questions via twitter with #EpidemicPhilly.

Biographies of the panelists and moderator

Mitesh Patel
Mitesh S. Patel, MD, MBA, MS is a board-certified general internist, physician scientist, and entrepreneur. He is an Assistant Professor of Medicine and Health Care Management at the Perelman School of Medicine and The Wharton School at the University of Pennsylvania. His work focuses on leveraging behavioral economics, connected health approaches and data science to improve population health and increase value within the health care delivery system. 

As a physician-scientist, Mitesh studies how we can utilize innovative technology and connected health approaches to passively monitor activity and how we can use health incentives to motivate behavior change. His prior work has been published in NEJM, JAMA, the Annals of Internal Medicine and featured in the New York Times, NPR, and CNN. Mitesh also co-founded, Docphin, a startup that strives to improve the application of evidence-based medicine into clinical practice.

Mitesh holds undergraduate degrees in Economics and Biochemistry as well as a Medical Doctorate from the University of Michigan. He obtained an MBA in Health Care Management from The Wharton School and an MS in Health Policy Research from the Perelman School of Medicine at the University of Pennsylvania. Mitesh completed his internal medicine residency training and the Robert Wood Johnson Clinical Scholars Program at the University of Pennsylvania.

James Garrow

James Garrow, MPH is a nationally recognized proponent and advocate for the use of social media and digital tools in the execution of public health activities. His role as the Director of Digital Public Health in Philadelphia is among the first in the country charged with using new digital tools and techniques like social media, crowdsourcing, and big data utilization. He also provides media relations support for the Philadelphia Department of Public Health.

An accomplished public speaker and noted thought leader, Jim has been invited to and spoken at conferences across the US on social media use in public health and emergency response. He is an active social media user, maintaining two regularly scheduled Twitterchats and a blog on crisis and emergency risk communications.

Jim obtained a B.S. in Applied Sociology from Drexel in 2001 and a Master’s of Public Health from Temple in 2011. 

Giang T. Nguyen

Dr. Nguyen, MD, MPH, MSCE, is an Assistant Professor in the School of Medicine, Department of Family Medicine and Community Health at Penn.  He is also Chair of the MD-MPH Advisory Committee and a member of the MPH Program Curriculum Committee.

Dr. Nguyen leads the Penn Asian Health Initiatives. His research focus is in Asian immigrant health with concentrations in cancer control, disease prevention, and community-based participatory research. His community engagement work has included outreach to Vietnamese and other Southeast Asian refugees, health fairs and immunization clinics, cancer education workshops, advocacy, HIV/AIDS, and LGBT issues. He serves on boards and advisory committees for several Asian serving organizations, including the Asian and Pacific Islander National Cancer Survivors Network.

Dr. Nguyen is also the Medical Director of Penn Family Care, the clinical practice of the University of Pennsylvania's Department of Family Medicine and Community Health. He provides direct care to adult and pediatric patients in the primary care setting and teaches medical students and family medicine residents. He also is a Senior Fellow of the Penn Center for Public Health Initiatives, where he is a core faculty member for the Penn MPH program.
Max King
Previously the coordinator of Penn State's University Scholars Program, Max King, Ph.D., MS, is now Associate Vice Provost for Health and Academic Services at The University of Pennsylvania.
Dr. King holds three degrees from Penn State: a B.S. in Biological Health, M.S. in Health Education, and Ph.D. from the Interdisciplinary Program in Educational Theory and Policy. His research focus is the multidimensional Methodology of Q-Analysis, or Polyhedral Dynamics, a higher-level structural analysis approach derived from algebraic topology.

Dr. King also held an appointment as an Affiliate Assistant Professor and a member of the graduate faculty in the Department of Administration, Policy, Foundations, and Comparative/International Education at Penn State. He taught educational foundations, comparative education, British education, research methods, and international education. He also has extensive experience in computer systems, developing mainframe and microcomputer research and thesis applications.

Friday, October 16, 2015

NIH to chimera researchers: Let's talk about this...

by Chris Yarosh

When we think about the role of the National Institutes of Health (NIH) in biomedical research, we often think only in terms of dollars and cents. The NIH is a funding agency, after all, and most researchers submit grants with this relationship in mind. However, because the NIH holds the power of the purse, it also plays a large role in dictating the scope of biomedical research conducted in the U.S. It is noteworthy, then, that the NIH recently delayed some high profile grant applications related to one type of research: chimeras.

Chimeras, named for a Greek mythological monster composed of several different animals, are organisms that feature cells that are genetically distinct.  In the lab, this commonly refers to animals that contain cells from more than once species. Research into chimeras is not new; scientists have been successfully using animal/animal (e.g. sheep/goat) chimeras for over 30 years to learn about how animals develop. Human/animal chimeras are also a common research tool. For example, the transfer of cancerous human tissue into mice with weakened immune systems is standard practice in cancer biology research because it allows researchers to test chemotherapy drugs in a system that is more complex than a dish of cells before testing them in human subjects. These experiments are largely uncontroversial, save for individuals who fall into the anti-animal testing camp (and those who dispute the predictive power of mouse models in general). Why then, has the NIH decided to pump the brakes on this line of research?

Like many things, the answer lies in the timing. The temporarily-stalled research involves injecting human pluripotent cells—undifferentiated cells that can develop into any number of different cell types—not into mature animals, but instead into animal embryos. Unlike the tumor-in-a-mouse research mentioned above, this kind of experiment is specifically trying to get normal human cells to develop as an animal matures and remain, well, normal human cells. One idea is that someday we could grow an organ (liver, pancreas, etc.) in an animal, such as a pig, that is still a human organ. This would lower the barrier for successful transplantation, meaning that somebody in serious need of a new liver could receive one from livestock instead of waiting for a human donor from a transplant list. Another thought is that chimeric animals will better model human physiology, making subsequent clinical trials more accurate.

If you read the last paragraph and felt a bit uneasy, you’re not alone. For some, this type of research crosses the invisible line that separates humans from animals, and is therefore unacceptable. Others find this research troubling from an animal welfare standpoint, and still other worry about unanticipated differentiation (e.g. “we wanted a liver, but we found some human cells in the pig’s nerves, too”) or unethical uses for this type of technology.

The NIH hears these concerns, and wants to talk about them before giving scientists the go ahead to use public funds on this type of research. Some researchers have reacted negatively to this, fearing broader restrictions in the future, but I think this is an important part of the scientific process. We live (and for scientists, work) in an era of unprecedented ability to modify genomes and cell lineages, and human/animal chimeras are just one example of a type of research destined for more attention and oversight. It is important to get the guidelines right.

The NIH will convene a panel of scientists and bioethicists to discuss human/animal chimera research on November 6th, so keep an eye out for possible policy revisions after then. Given the promise of this type of research and the potential concerns over its use, this surely is only the beginning of the deliberative process.

UPDATE (11/05/2015): Scientists from Stanford University have posted an open letter in Science calling for a repeal of the current restrictions in this field. The full letter, found here, argues that there is little scientific justification for the NIH's stated concerns. Over at Gizmodo,  the NIH has responded by claiming that the true purpose of the stop order and review is to "stay ahead" of current research and anticipate future work. This is consistent with the NIH's views as articulated on the Under the Poliscope blog. All things considered, the workshop tomorrow, and any guidelines resulting from it, should be very interesting for people who wish to develop and use these tools.