David Bennett, a 57-year-old American diagnosed with terminal heart disease, had spent the last six weeks bedridden attached to a machine that kept him alive. Due to this decaying condition, the man was not eligible for a heart transplant. It seems like there was no hope left, but the restriction only applied to human hearts. Mr. Bennett was given a second shot by doctors at the University of Maryland Medical Center who, during a grueling seven-hour surgery, replaced his failing heart with that of a genetically-modified pig. This is the first time the heart of a pig has been transplanted into a human, a procedure known as xenotransplantation.
A medical gamble
In the second half of 2021, surgeons at New York University Langone Health successfully grafted a pig kidney to a human. They actually did this twice. However, both patients were brain-dead and the kidneys from the ungulates were externally attached to the human body via a large blood vessel. By contrast, Mr. Bennett is conscious and could prove that xenotransplantation actually works in the real world.
Out of all mammals, a pig’s organs are the most compatible with those of humans in terms of size and metabolism. For many years, doctors have already been using pig valves in replacement surgeries. But even so, an untreated pig heart will be quickly and furiously rejected by the human body, which is why the animal used in the transplant had been genetically modified to knock out several genes that express molecules that humans do not. Biocompatibility can make or break a transplant and issues can appear even between organs sourced from humans, not to mention those belonging to an entirely different species.
The procedure was deemed a success. The transplanted heart is beating a pulse and drives pressure, but it is too quick to draw definite conclusions. The patient might live only a few extra days or weeks, but he could just as well live another year — such is the nature of experimental medical procedures on the terminally ill.
“It’s working and it looks normal. We are thrilled, but we don’t know what tomorrow will bring us. This has never been done before,” said Dr. Bartley Griffith, the director of the cardiac transplant program at the University of Maryland and one of the doctors who performed the procedure.
More than 100,000 Americans are on organ transplant waiting lists. Demand far exceeds supply, with thousands dying each year in the U.S. before they get their chance at a transplant. Although more Americans received a human donor heart in 2021 than ever before, there’s still an acute shortage of organ donors. In this context, xenotransplantation represents a silver lining.
Scientists hope that animal-to-human organ transplants will become one day become the norm, revolutionizing the way we treat organ failure. However, entering this door is not without its many challenges. Organ rejection regularly occurs even between seemingly well-matched human donors and recipients.
Mr. Bennett decided to choose this unproven procedure because he had no other options. Although his condition is currently stable, his prognosis is rife with uncertainty. He is still hooked up to machines that assist in breathing and heart functioning and is scheduled to be taken off these machines next week. During this time, the patient will be closely monitored, especially in the first 48 hours that are particularly critical.
“It was either die or do this transplant,” Mr. Bennett said before the surgery, according to officials at the University of Maryland Medical Center. “I want to live. I know it’s a shot in the dark, but it’s my last choice.”
The lush environment of Indonesia harbors some of the oldest known cave art. Now, it can officially boast having the oldest known cave art. Dated to 45,500 years ago, this prehistoric figurative painting depicts a Sulawesi warty pig — and researchers say there should be more like it in the area.
Sulawesi is an Indonesian island east of Borneo. Rich in lush vegetation and karst environment, it would have been an excellent home for early humans. Unsurprisingly, then, the island has a long history of human occupation, with stone artifacts dating up to 194,000 years ago, possibly from a yet-unidentified ancient human species.
The Leang Tedongne cave, where the painting was discovered, lies in a narrow valley, enclosed by steep limestone cliffs — exactly the type of karstic landscape you’d expect to find caves in. Doctoral Student Basran Burhan came across the painting during 2017 surveys carried out with local authorities and members of the local Bugis community.
The cave is only accessible during the dry season as the valley gets flooded during rainy season. In fact, it’s so inaccessible that Bugis members told researchers the cave had never been seen by Westeners before.
Measuring 136 by 54 centimeters (53 by 21 inches), the Sulawesi warty pig is painted in a single dark red color. It has a short crest of upright hair and a pair of horn-like warts, which help researchers identify the species of the pig. There are also two hand prints near the pig, as well as two partially preserved pigs, suggesting that it could have been a larger narrative scene.
The painting also features an artistic technique often found in ancient cave paintings, the researchers note in the study.
“It should be noted that the artists portrayed preorbital warts in the so-named twisted perspective. This is a common method of graphical representation in prehistoric art that entails using a single outline profile image of an animal to depict how it appears to an onlooker when observed from different viewpoints.”
“The pig appears to be observing a fight or social interaction between two other warty pigs,” said co-author Adam Brumm.
Sulawesi warty pigs have been hunted for tens of thousands of years in Indonesia, and have even been domesticated in some regions. It’s unsurprising then that these creatures feature prominently in cave art.
The researchers also analyzed a couple of other cave paintings, dating them and identifying the depicted species. The previous oldest cave art was dated from 43,900 years ago, also from Indonesia.
Could be even older
Since the maximum age that can be dated using carbon dating is 50,000 years, the cave painting was dated using another method: uranium dating. However, the team didn’t date the paint itself to prevent any damage, but rather the layer of calcite that formed on top of the painting. This means that the painting itself “could be much older because the dating that we’re using only dates the calcite on top of it,” they say.
But even if the painting dates from so long ago, the people who made it were, by any definition, people. The team believes the artwork was made by Homo sapiens and not another, now-extinct human species like Denisovans (or another unidentified species) but cannot say this for certain at this moment. Regardless of what species made it, they were still people, researchers conclude.
“The people who made it were fully modern, they were just like us, they had all of the capacity and the tools to do any painting that they liked,” he added.
Since the depicted scene also features a couple of handprints, researchers are hoping to get some DNA samples and see what species created the art. In order to produce these handprints, the artists would have had to place their hand on the wall and then spit pigment over it — traces of that may yet be discovered, shedding new light on this ancient episode of human evolution.
Pigs were also faster than dogs in solving the task researchers handed to them, adding more weight to the intelligence of these mammals.
We’ve known for quite a while that pigs are intelligent, emotional, and cognitively complex. They love to play, they exhibit a wide range of emotions and relationships, and they’re quite good at problem-solving.
In a new study, researchers at Eötvös Loránd University, Budapest (ELTE) compared the problem-solving attitudes of dogs to those of humans.
In neutral situations, both dogs and pigs look to humans for interaction. But when faced with an unsolvable problem, dogs exhibit spontaneous human-oriented behaviors, attempting to initiate communication. In other words, dogs look to humans for help when it comes to problem solving.
Meanwhile, pigs tend to be more independent thinkers. Much like wolves and other animals, pigs attempt to solve problems on their own, without the help of humans.
“Similarly socialized wolves and cats communicate less with humans than dogs in the same problem-solving context, but maybe it is because wolves are not domesticated, and cats are not a social species. So we designed a study to compare dogs’ behavior with that of another domestic and social species, the pig,” explains Ph.D. student Paula Pérez.
To put the hypothesis to the test, they tested 10 companion miniature pigs, raised as pets (just as people raise dogs). Since the pigs were exposed to a similar environment to pet dogs, this puts them on an equal footing and eliminates the impact of the environment in which the animals grew up in.
“We launched the Family Pig Project in 2017 at the Department of Ethology, Budapest. The animals are raised in a similar environment as family dogs, providing the basis for unique comparative investigations between the two species,” explains Attila Andics, principal investigator of the MTA-ELTE ‘Lendület’ Neuroethology of Communication Research Group.
In the study, the animals first had to solve a simple problem: a transparent plastic container containing food that they had to turn upside down to get access to the food.
Then, the problem became unsolvable, and the container was fixed in place. There were two goals: the first one was to see how easily pigs solve the problem compared to dogs. The second was to see how pigs behaved when they couldn’t solve the problems.
As it turns out, pigs were faster than dogs (although this could be attributed to their ease of turning the container).
However, when they couldn’t solve the problem, they didn’t look for external help, and instead tried to handle things on their own.
“We used the so called ‘Unsolvable task paradigm,’ where the animal first faces a problem that he can solve, in our case an easy-to-open box with food inside. After some trials, the problem becomes unsolvable because the box is securely closed,” adds Pérez. “When the box was first in the room without food in it, pigs and dogs performed similar human-oriented behaviors,” says Linda Gerencsér, research fellow at the Research Group. “The differences appeared when we put food in the box and opening it became an exciting challenge. Pigs were faster than dogs already in solving the task and getting the reward, perhaps due to their better manipulative capacities. Then, when the task became unsolvable, dogs turned to the humans more than before. In contrast, pigs performed less human-oriented behaviors, but they were more persistent than dogs in trying to solve the task, which may reflect their predisposition to solve problems independently.”
This is the first study to directly compare family dogs and pigs’ problem-solving abilities, and shows just how able pigs really are. They are as smart, and a bit more independent than our best friends.
Although in small quantities of under 70 grams (2.5 ounces) / day, red meat is not as harmful to your health, consumption of pork is associated with a significant risk of several chronic conditions including diabetes, cardiovascular disease, and several types of cancer.
“I would never recommend eating animal products, and certainly not pork,” says Dana Hunnes, assistant professor at the UCLA Fielding School of Public Health.
The main (but not the only) reason why pork is bad for you is its high content of saturated fats and cholesterol. However, as is often the case with nutrition, the scientific studies are not always clear-cut, and dietary recommendations tend to be laxer than existing evidence.
We eat too much pork
Pigs were domesticated in Mesopotamia, around 15,000 years ago. But up until the 20th century, consumption of pork was relatively low, and often restricted to the autumn-winter part of the year.
In the 20th century, mankind rethought its animal consumption, and industrial farming took over. The world now produces 4 times more meat than 50 years ago — which in 2013, meant 320 million tons of meat. Over 80 billion animals are slaughtered each year for meat, with pig meat being the most popular type of meat globally (although poultry is increasing most rapidly).
The average American consumes 124 kilograms of meat every year, and around 24 of those are pig. Pork (the “food” name of pigs) is consumed in a number of ways, from sausages and bacon to fresh meat and lard.
Pork consumption in the US has remained relatively stable for much of the past century (although chicken, turkey, and beef have increased compared to the early 1900s). But this doesn’t necessarily mean good news.
Virtually all dietary guidelines recommend no more than 500 grams (1.1 pounds) of red meat a week — not just pork. Meanwhile, Americans consume double that, and the numbers keep growing.
It’s not just Americans (although the US is near the top of the list for per capita red meat consumption) — as the world is becoming more affluent, it is consuming more red meat, and pork is a staple in many parts of the world.
Despite some claims from the industry, pork is undoubtedly red meat. In particular, one advertising campaign from the U.S. National Pork Board labeled pork as “the other white meat”. The campaign was highly successful, and at some point, 87% of consumers identified pork with the slogan, although the USDA never considered pork to be anything other than red meat.
“Pork is considered a red meat, and it is high levels of saturated fat, and all of the other animal protein compounds that are deleterious to health. Pork is not a “white meat”, and even if it were, white meat has also been demonstrated to be deleterious to health,” Hunnes told ZME Science.
Is pork bad for you?
In 2012, a large study on over 100,000 individuals found strong evidence that consumption of red meat is linked to a shorter and less healthy life. The evidence was strong, although pork wasn’t analyzed in particular — this is often the case with such studies, they classify all red meat together.
“This study provides clear evidence that regular consumption of red meat, especially processed meat, contributes substantially to premature death,” according to Dr. Frank Hu, one of the senior scientists involved in the study and a professor of nutrition at the Harvard School of Public Health.
It was by no means an isolated study. Studies have highlighted the health risks associated with pork consumption for decades. Sometimes, it’s not always obvious problems — for instance, a 1985 study finding a correlation between pork consumption and cirrhosis. But most of the time, the same health problems pop up. Despite the fact that pork can be a source of nutrients such as protein and iron, it is associated with a number of health problems.
Pork consumption and cancer
In 2015, the International Agency for Research on Cancer concluded that red meat is probably carcinogenic to humans. Several types of cancer have been linked to pork. For instance, a 2011 analysis found that for each additional 100 grams of red meat (either pork or beef) per day, the risk of colorectal cancer increases by 17%. Correlations were also observed for pancreatic and prostate cancer, although the associations were not as strong.
“High intake of red and processed meat is associated with significant increased risk of colorectal, colon and rectal cancers,” the study concluded.
Even moderate intake of pork can increase the cancer risk, another study found. The study, carried out in 2019, found that even red meat consumption in accordance with existing guidelines leads to an increased bowel cancer risk: 20% with each extra slice of ham or rasher of bacon per day. This is particularly significant because it shows that the risk has remained significant even as people’s diets may have changed over the years.
It’s worth noting that all these are big studies — and there’s more. A 2013 meta-analysis (a study of studies) found that gastric cancer risk also increases with red meat consumption, although the authors called for more research to clarify this connection.
A 2016 literature review found that for 100g or more per day of red meat, the risk breast cancer increases by 11%, 17% for colorectal cancer, and 19% for prostate cancer.
“Red meat products, especially those that have been processed, have a wide variety of carcinogenic molecules known to increase the risk of colorectal cancer,” the study concluded.
It should be noted that this is an increase in relative risk. Let’s take an example.
Let’s say the cancer risk is 10%, and pork consumption causes a 17% increase in the total cancer risk. The net increase in risk is 17% of 10% — so in total, it’s a 1.7% increase that takes the total risk from 10 to 11.7%.
Some use this to claim that the disease risk from red meat is exaggerated. At the end of the day, we all judge risk in our own way, and one may consider the extra risk acceptable — but even a 1% change is huge considering how common these diseases are.
The exact risk is hard to establish, but overall, pork consumption seems to be linked with higher cancer risk. There is “sufficient evidence” to draw a link between the consumption of processed meat products and cancer, WHO experts also conclude.
Pork consumption and obesity
It’s no secret that the world (and especially the developed world) is facing an obesity crisis. Decades ago, the culprit was considered to be fat, whereas in more recent years, sugar has also emerged as a major issue. However, according to a recent study, meat is also to blame.
“In the analysis of obesity prevalence across 170 countries, we have found that sugar availability in a nation explains 50% of obesity variation while meat availability another 50%. After correcting for differences in nations’ wealth (Gross Domestic Product), calorie consumption, levels of urbanization and of physical inactivity, which are all major contributors to obesity, sugar availability remained an important factor, contributing independently 13%, while meat contributed another 13% to obesity,” said Professor Maciej Henneberg, head of the Biological Anthropology and Comparative Anatomy Research Unit, and one of the study authors.
Again, the effect of individual meats was not calculated, but overall, high meat availability was found to be correlated with obesity. It’s also worth noting that it’s not necessarily the fat, but also the protein in the meat that contributes to obesity.
According to another 2014 review of studies covering a combined total over 1 million participants, “red and processed meat intake is directly associated with risk of obesity, and higher BMI.”
The key to understanding these nutritional studies is to look at the big picture. You will always find differences between individual studies, and you can find studies that support varying viewpoints.
If you want to have a better understanding of this process, it’s best to look at large-scale studies and reviews of studies.
The fact that many diet-and-disease studies lump pork together with other types of red meat also dilutes the association related to pork alone.
According to the Global Burden of Disease study 4.7 million people died prematurely in 2017 as a result of obesity. Obesity is one of the most important health risk factors. According to recent estimates
Pork consumption and the link to diabetes and cardiovascular disease
This is where things are not as clear as before. Because red meat consumption is associated with increased weight, and increased weight is associated with diabetes and cardiovascular disease, it’s doubly difficult to assess which risks are caused directly by meat, and which by increased weight. This is why studies in this regard are often inconclusive and hard to interpret.
Even so, the prevailing evidence seems to show negative effects of red meat consumption.
A 2011 study on over 100,000 participants found that “red meat consumption, particularly processed red meat, is associated with an increased risk of type 2 diabetes.” Substituting one serving of red meat per day with nuts, low-fat dairy and whole grains reduces the risk of type 2 diabetes by up to 35%. Another study, one year earlier, concluded that a “reduction of the consumption of processed meat may help prevent the global epidemic of type 2 diabetes”.
A review of almost half a million people found a positive link between red meat consumption and cardiovascular disease and overall mortality. Eating red meat daily triples the levels of a heart disease-related chemical called TMAO.
“These findings reinforce current dietary recommendations that encourage all ages to follow a heart-healthy eating plan that limits red meat,” says nutrition researcher Dr. Charlotte Pratt, the NHLBI project officer for the study. “This means eating a variety of foods, including more vegetables, fruits, whole grains, low-fat dairy foods, and plant-based protein sources such as beans and peas.”
Another recent study has found that eating two servings of red meat per week was linked to a 7% higher risk of heart and circulatory diseases, compared to eating none at all (again, this is relative risk).
However, another study concluded that eating meat within the recommended quantity does not increase cardiovascular risk, and recent studies have called for more studies on this issue.
A part of the reason why nutritional studies are so hard to reconcile is that they often rely on self-reported questionnaires. Humans are notoriously unreliable when it comes to self-reporting and often tend to distort the data.
This is why it’s important to look at results from multiple angles, and when possible, also try to find the mechanism producing the observed effect.
Another important aspect is how the meat is prepared: is it processed, and if yes, how? Is it cooked at high temperatures? All this can matter. As a rule of thumb, the more it is processed and cooked, the worse it is. This is particularly concerning since pork is often consumed in processed form (in products such as bacon or sausages), which seem to have an even higher health risk.
Other health risks associated with pork consumption: liver disease, MS, yersinia
Some of the health issues associated with pork consumption tend to fly under the radar.
For instance, the link between pork and multiple sclerosis (MS) is known at least since the 1980s, and has been demonstrated across dozens of countries. The link has been supported by multiple studies carried in various environments. It’s more than just an observation: between 2007 and 2009, a cluster of 24 pork plant workers fell mysteriously ill with a disease that triggers MS-like symptoms — a problem which was ultimately traced back to pork.
Remember the 1985 cirrhosis study we mentioned at the start of the article? Surprisingly, pork can also cause liver disease, including cirrhosis and liver cancer. Alcohol is of course a main driver here, but pig meat has been repeatedly proven to play a role in both liver cancer and cirrhosis.
Yersinia is another potential risk factor that is often overlooked. In pork that isn’t properly cooked, the Yersinia bacteria can creep in, causing severe symptoms and even contributing to mortality. In the US alone, yersinia kills 35 people and causes 117,000 cases of food poisoning each year. Its main point of access inside the human body? You’ve guessed it — pork. The problem can be averted by properly cooking the meat.
Can pork ever be good for you?
Every once in a while, you end up seeing a “pork isn’t bad for you” study picked up by the media. Recently, one such study published in late 2019 made all the rounds. “Red meat is back on the menu” and “Stop worrying about red meat” were just some of the headlines flown around, validating what meat lovers all around the world wanted to hear. But there’s a problem — several, actually.
This was just one study, the authors themselves admitted low-quality evidence, and the study was called into question in more ways than one (see our detailed analysis of that study here).
A Professor of Medicine and Human Nutrition at University of Otago, New Zealand, summed up the general feeling among scientists:
“In my opinion, the weak recommendation based on low-certainty evidence that adults continue current consumption of unprocessed red meat and processed meat is potentially unhelpful and could be misleading.”
This doesn’t mean that the study is meaningless or that we should immediately disregard conflicting evidence — but neither should we overturn decades of research because a conflicting study came out. This just means that we shouldn’t jump on the next study that gets picked up by the media. Instead, looking at multiple, large studies can offer a much more accurate image.
It can be daunting to look through studies when all you want is to know whether bacon is alright, so if you want to boil it down to a simple tidbit, it’s hard to see pork as part of a healthy diet.
“All animal proteins, exclusive of what animal they come from, can be harmful to health, especially if and when they are processed. So I would never recommend eating animal products, and certainly not pork,” says Hunnes.
This being said, if your diet is low in salts, saturated fats and you have an active lifestyle, you can incorporate low amounts of lean, preferably unprocessed pork into your diet, and will still have a relatively low risk of developing chronic diseases.
There are many things we don’t fully understand about nutrition, but what we do know is that the total matters more than the sum of the parts. Some things are healthier than others, and it’s important to be careful with all aspects of your lifestyle.
However as Havard researchers have pointed out, even the dietary guidelines sometimes don’t take into consideration the risks that their very own analyses highlight.
But don’t you need red meat for protein?
As mentioned, pork can contain large amounts of protein, but the idea that you need to eat red meat to get your protein is a myth.
“We need nutrients, and we need amino acids that come from protein, but neither of these do we need from animal proteins,” Hunne explains.
Replacing red meat with plant protein has been found to increase longevity and improve overall health in a number of studies. While people who don’t eat much meat (or don’t eat meat at all) need to pay some attention to complementing their protein and vitamin intake, diets focused on plant rather than animal protein tend to be associated with better health outcomes.
In 2006, a study compared plant with animal protein, concluding that “with a proper combination of sources, vegetable proteins may provide similar benefits as protein from animal sources.”
Results of a 2016 meta-analysis found that plant-based protein is associated with a lower risk of disease of all-cause mortality, and cardiovascular problems — a link that was especially prevalent for people who have at least one health risk factor.
“Substitution of plant protein for animal protein, especially that from processed red meat, was associated with lower mortality, suggesting the importance of protein source.”
The bottom line
Consumption of meat, in any quantity, can be detrimental to your health in a number of ways, and generally speaking, the more you eat, the more you increase your risk.
Not all pork is made equal. Uncooked meat can carry pathogens, while processed meat tends to be worse. Meat that is high in saturated fats and trans fats causes the greatest risk to health.
Multiple conditions have been associated with pork consumption, including but not limited to diabetes, MS, cardiovascular disease, obesity, cirrhosis, and multiple types of cancer. The exact nature of this risk is still a matter of active research, but if you want to be on the safe side, no amount of pork is safe. If you just can’t give it up, the common recommendation is to not go over 500 g (1.1 pounds) per week and stick to lean, unprocessed meat.
Substituting red meat protein with plant protein is linked to a longer, healthier life, with multiple studies backing this up. Reducing pork consumption can also have a positive environmental impact, reducing the greenhouse gas emissions and water consumption associated with our food. Ethically, slaughtering billions of animals every year (especially animals as — or even more — intelligent than dogs) is not the right thing to do.
Oh, and there’s another reason why avoiding pork might be wise, Hunnes notes.
“In the past couple of decades, a couple of disease epidemics (swine flus) have emerged from pigs. Just another reason not to raise animals in confinement.
In short, I do not recommend eating pork. Under any circumstances,” she concludes.
Chinese scientists are now desperately seeking government approval to launch a clinical trial for xenotransplantation. The goal is to have genetically modified pig organs transplanted into humans. This could happen as early as 2019.
Every country on Earth is in short supply of organs for transplants with some patients staying on waiting lists for years, some over a decade. Suffice to say most die from health complications before they get a chance to receive a heart, lung or kidney. This situation could go on forever unless we find a way to literally grow transplant organs.
An unbeaten path
One promising approach involves genetically modifying pigs whose organs can then be transplanted to a human patient. This procedure is referred to as xenotransplantation. Out of all mammals, a pig’s organs are the most compatible with those of humans in terms of size and metabolism.
To demonstrate how such a procedure might work, scientists working with the National Heart, Lung and Blood Institute, USA, grafted a pig’s heart to a baboon’s last year. The researchers suppressed the alpha 1-3 galactosyltransferase gene which produces an epitope that is easily recognized as foreign. This way, the baboon’s immune system doesn’t attack the pig heart although immunosuppressants still had to be taken. Amazingly, the longest a pig heart kept beating was 945 days or nearly three years.
The leader in this field, however, is China. According to the South China Morning Post, about 1,000 cloned pigs are made inside dedicate clone farms around China.
Also in China, no fewer than ten national institutes are closely collaborating for xenotransplantation project funded by the central government. Already, there is fantastic progress. For instance, 400 cornea transplants have been performed from pigs to humans with a stunning 95 percent success rate once the Chinese government gave the green light in 2015.
Now, the same scientific consortium is looking permission from the government to make the next big step: a clinical trial for organ xenotransplantation.
This could happen as early as two years from now, South China Morning Post reported, although there’s a good chance the deadline could be extended even further. It seems like the Chinese government is delaying giving the go. Corneas, which don’t contain blood vessels, are one thing but an organ which can be mind-wrecking complex is a whole different ballgame.
“We have patients dying from organ failure and their desperate relatives pleading for them to have the chance to live,” said Zhao Zijian, director of the Metabolic Disease Research Centre at Nanjing Medical University in Jiangsu.
“But when we turn to the authorities in charge of approving the clinical trials, all we get is silence. We understand it must be very hard for the government to make a decision, but it’s time we got an answer,” he added.
Zhao admitted, however, that genetically modified pig organs are barely a 50 percent match for human organs. According to the Chinese leading scientist, it’s quite possible that a pig organ transplanted tomorrow inside a human’s body won’t get rejected. The big risk though is in the long term such as inflammation as a result of the immune system attacking the transplanted heart or lung.
Even in such an experimental stage, however, for many patients, such a procedure would be much welcomed. In the end, there can’t be progress absent clinical trials.
“Someone has to take the first step – whether it’s the US Food and Drug Administration or the China Food and Drug Administration,” he said.
Five baboons were each hooked up with a pig heart alongside their own hearts. Essentially, these baboons lived with two hearts and the pig one still functioned two years on average after the grafting, marking a marvelous breakthrough in xenografting. The longest a pig heart kept beating was 945 days or nearly three years.
The hearts were sourced from genetically modified piglets, engineered for biocompatibility with the baboon organism. The researchers suppressed the alpha 1-3 galactosyltransferase gene which produces an epitope that is easily recognized as foreign. The process isn’t perfect though, so the baboons had to kept for the whole duration of the experiment on immunosuppressants, not all that different to those that humans who undergo heart transplant have to take for all their lives.
“This milestone shattered previous records of pig-to-primate heart transplant also achieved by this group of researchers over past five years,” the National Heart, Lung and Blood Institute announced in a news release.
Previously, the same researchers grafted hearts to baboons that survived for more than 200 days, but this latest attempt is far more successful. The end goal is to eventually have a primate survive on a single heart from a foreign species, likely a pig. This would open an avenue for human hybrid transplants. Another more Frankenstein line of research involves growing human hearts directly into a pig or some other animal and having it transplanted afterward. The heart would be grown from cells collected from the would-be recipient so, theoretically, it would be like a getting a new heart specially built for the recipient with fewer risks of immune rejection. Technical challenges are huge at this point, though.
Chinese researchers have genetically modified pigs to grow about as big as a medium-sized dog, and they will soon go up for sale, the Beijing Genomics Institute (BGI) announced last week. Many researchers have expressed concerns about using such advanced techniques for such frivolous purposes, and personally, I feel like this could cascade onto many other problems – despite their undeniable cuteness.
BGI in Shenzhen, the genomics institute that is famous for a series of high-profile breakthroughs in genomic sequencing, originally created the micropigs as models for human disease. Unlike rats for example, pigs have much more in common to human physiology, which makes them a much more useful model. But their large size brings along many logistic and financial problems. Bama pigs, which weigh 35–50 kilograms, have often been used in research – but Chinese researchers engineered them to get even smaller.
The animals grew up to 15 kilograms, and this made really attractive for the general public – who wanted them as dog-like pets; researchers paid attention to the public demand, and a week ago, on 23 September, at the Shenzhen International Biotech Leaders Summit in China, BGI revealed that it would start selling the pigs, starting at $1600. Furthermore, in the future, customers will be offered pigs with different coat colours and patterns, which BGI says it can also genetically engineer.
But the alarm signals are already being raised.
“It’s questionable whether we should impact the life, health and well-being of other animal species on this planet light-heartedly,” says geneticist Jens Boch at the Martin Luther University of Halle-Wittenberg in Germany. Boch helped to develop the gene-editing technique used to create the pigs, which uses enzymes known as TALENs (transcription activator-like effector nucleases) to disable certain genes.
BGI showcases its micropigs at a summit in Shenzhen, China.
The decision to sell these pigs as pets also surprised Lars Bolund, a medical geneticist at Aarhus University in Denmark who helped BGI to develop its pig gene-editing programme, and it’s easy to see where this could go extremely wrong.
First of all, micropigs will almost certainly additional medical problems, similar to pets created by selective breeding. Many pure-breed dogs and cats suffer many health conditions, and the growing consensus seems to be that pure-bred dogs should be phased out for their own good. Also, if this is done on pigs, it only seems like a matter of time before the same is done for dogs and cats. Jeantine Lunshof, a bioethicist at Harvard Medical School in Boston, Massachusetts described it as “stretching physiological limits for the sole purpose of satisfying idiosyncratic aesthetic preferences of humans” – but then again, the same can be said about selective breeding. Dana Carroll, a gene-editing pioneer at the University of Utah in Salt Lake City, adds:
“I can certainly imagine resistance to manipulating dogs, even though all of the current breeds are the result of selective breeding by humans.”
The pace and scale of China’s economic transformation have no historical precedent. In 1979, China initiated a series of reforms which set the country in economic high gear producing some of the most fundamental changes ever to occur in any country. China’s annual average GDP per capita growth in the last ten year period was 9.9 percent, compounding to a total increase in GDP per capita of 158 percent. This astonishing growth has however also fueled some of the most profound social and environmental shifts. What’s funny about China’s economic growth is that it can be correlated to an unlikely proxy: pigs.
A food wholesale center near Shanghai.Qilai Shen/Bloomberg News
According to The Economist, the Chinese are fattening up on their favorite vegetable: pork. This may sound like a cruel joke, but you might first want to consider that Chinese pigs are gobbling up nearly half the world’s feed crops. Already in 2010 China’s soy imports accounted for more than 50% of the total global soy market, and grain imports a skyrocketing. The US Grains Council, a trade body, predicts that by 2022 China will need to import 19m-32m tonnes of corn, almost a third of the world’s entire trade in corn today.
You may have heard about how China is buying real estate all over the world. Some 5m hectares have been bought in developing countries alone, according to Sustainable Development, a Canadian think-tank. Of course, this land is used to raise buildings, factories, other business or just to control the market, but much of it will also be used as farm land. Shuanghui, China’s largest pork producer, bought Smithfield Foods, an American firm, in 2013 and with it acquired huge stretches of Missouri and Texas. So, what? The rest of world eats a lot of pork too. Yes, but the average Chinese eats 39kg of pork per year – more than Americans, who granted prefer beef. To put things into perspective, that’s five times more per person than they ate in 1979. In 1949, most people in China got only 3% of their annual calorific intake from meat.
The Chinese are in love with pork meat, which is deeply linked with prosperity. In Mandarin the word for “meat” and “pork” are the same. The character for “family” is a pig under a roof. But, historically, the Chinese ate little pork because it wasn’t plentiful. When China grows, so do its pigs. In fact, it’s so deeply tied to its economy that in 2007 when 45 million pigs were killed by “blue ear pig disease”, not only did pork prices skyrocket, but all other products as well. The the annual rate of increase of the consumer price index – an index that gauges consumption – is also called the “consumer pig index”. In fact, the government set up the world’s first pork reserve! Millions of pigs are owned by the government – some frozen, others alive – and released on the market when pigs become too expensive.
The Chinese’s insatiable appetite for pork, however, comes at a hefty price. For each kg of pork meat, growers need to supply 6 kg of feed, typically processed soy or corn. As mentioned earlier, though, more than 50% of the world’s soy goes to China’s pigs. Argentina exports almost all of its soybean to China, and in order to grow more it has cut down thousands of hectares of forest.
Besides the displacement of CO2 sucking trees, pigs themselves contribute significantly to global warming. Like all animals, pigs release methane and nitrous oxide. Methane is a greenhouse gas which is 300 times more potent than CO2 at trapping heat. Greenhouse-gas emissions from Chinese agriculture increased by 35% between 1994 and 2005, and according to Tony Weis of the University of Western Ontario, Canada, livestock production is responsible for almost a fifth of emissions produced by human activity.
Both a symbol of prosperity, and a menace, the pig is yet to have its final say in Chinese life.