Scientists temporarily attached a pig’s kidney to a human body and watched it begin to work, a small step in the decades-long quest to one day use animal organs for life-saving transplants.
Pigs have been the most recent research focus to address the organ shortage, but among the hurdles: A sugar in pig cells, foreign to the human body, causes immediate organ rejection. The kidney for this experiment came from a gene-edited animal, engineered to eliminate that sugar and avoid an immune system attack.
Surgeons attached the pig kidney to a pair of large blood vessels outside the body of a deceased recipient so they could observe it for two days. The kidney did what it was supposed to do — filter waste and produce urine — and didn’t trigger rejection.
“It had absolutely normal function,” said Dr. Robert Montgomery, who led the surgical team last month at NYU Langone Health. “It didn’t have this immediate rejection that we have worried about.”
Revivicor via AP
FILE - This undated photo provided by Revivicor in December 2020 shows a "GalSafe" pig which was genetically engineered to eliminate a sugar in pig cells, foreign to the human body, which causes immediate organ rejection.
This research is “a significant step,” said Dr. Andrew Adams of the University of Minnesota Medical School, who was not part of the work. It will reassure patients, researchers and regulators “that we’re moving in the right direction.”
The dream of animal-to-human transplants — or xenotransplantation — goes back to the 17th century with stumbling attempts to use animal blood for transfusions. By the 20th century, surgeons were attempting transplants of organs from baboons into humans, notably Baby Fae, a dying infant, who lived 21 days with a baboon heart.
With no lasting success and much public uproar, scientists turned from primates to pigs, tinkering with their genes to bridge the species gap.
Pigs have advantages over monkeys and apes. They are produced for food, so using them for organs raises fewer ethical concerns. Pigs have large litters, short gestation periods and organs comparable to humans.
Pig heart valves also have been used successfully for decades in humans. The blood thinner heparin is derived from pig intestines. Pig skin grafts are used on burns and Chinese surgeons have used pig corneas to restore sight.
In the NYU case, researchers kept a deceased woman’s body going on a ventilator after her family agreed to the experiment. The woman had wished to donate her organs, but they weren’t suitable for traditional donation.
The family felt “there was a possibility that some good could come from this gift,” Montgomery said.
Montgomery himself received a transplant three years ago, a human heart from a donor with hepatitis C because he was willing to take any organ. “I was one of those people lying in an ICU waiting and not knowing whether an organ was going to come in time,” he said.
Several biotech companies are in the running to develop suitable pig organs for transplant to help ease the human organ shortage. More than 90,000 people in the U.S. are in line for a kidney transplant. Every day, 12 die while waiting.
The advance is a win for Revivicor, a subsidiary of United Therapeutics, the company that engineered the pig and its cousins, a herd of 100 raised in tightly controlled conditions at a facility in Iowa.
The pigs lack a gene that produces alpha-gal, the sugar that provokes an immediate attack from the human immune system.
In December, the Food and Drug Administration approved the gene alteration in the Revivicor pigs as safe for human food consumption and medicine.
But the FDA said developers would need to submit more paperwork before pig organs could be transplanted into living humans.
“This is an important step forward in realizing the promise of xenotransplantation, which will save thousands of lives each year in the not-too-distant future,” said United Therapeutics CEO Martine Rothblatt in a statement.
Experts say tests on nonhuman primates and last month’s experiment with a human body pave the way for the first experimental pig kidney or heart transplants in living people in the next several years.
Raising pigs to be organ donors feels wrong to some people, but it may grow more acceptable if concerns about animal welfare can be addressed, said Karen Maschke, a research scholar at the Hastings Center, who will help develop ethics and policy recommendations for the first clinical trials under a grant from the National Institutes of Health.
“The other issue is going to be: Should we be doing this just because we can?” Maschke said.
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If we are what we eat, then consuming nutritious foods is our surest way to maintain overall health.
With more than 700,000 COVID-19-related deaths in the U.S. reported by the Centers for Disease Control and Prevention, no other event to date has tested the capabilities of the immune system or called upon the importance of nutrition. According to the British Nutrition Foundation, recognizing key immune system-supporting nutrients and learning where to find them are two potent tools in maintaining a healthy lifestyle.
Lifestyle—diet in particular—directly affects the health of the immune system, and key nutrients play a major role in its proper functioning. Plant-based foods not only contain these key nutrients, but they also inadvertently support the immune system by reducing inflammation, decreasing the risk of cardiovascular disease, and even fighting cancer and Type 2 diabetes.
The main components of the immune system—cells, tissues, and organs—rely on nutritional choices to function as they should. When a foreign invader—or antigen—is identified, the immune system sends soldiers—antibodies—to fight it off. This is an immune response. The immune system remembers antigens, allowing antibodies to seek and destroy them quickly on the second, third, fourth, or more times around. This is immunity.
As flu season begins, already burdened by a pandemic, it’s more important than ever to support your immune system with curated nutrient-dependent decisions. Nutrition plays a key role in supporting your immune system, but medical professionals agree the best way to ensure a healthy and strong immune system is to pair a nutrient-rich diet with regular doctors visits and staying up-to-date on vaccinations.
Referencing research from scientific journals, including the American Journal of Lifestyle Medicine, the International Journal of Medicine and Medical Sciences, and the Food and Nutrition Bulletin, Thistle compiled a list of foods high in key nutrients that support the immune system, and they are highlighted below.
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- Key nutrient: Vitamin C
The citrus family of fruits—including oranges, lemons, limes, and grapefruits—is an excellent source of immune system-supporting vitamin C. As a powerful antioxidant and cofactor in immune defense, vitamin C is integral in supporting both innate and adaptive immune systems. Vitamin C is also important for bodily systems that contribute to immune health such as repairing tissue, aiding in wound healing, fighting free radicals, and maintaining the health of bones, skin, and blood vessels.
The human body isn’t capable of producing vitamin C on its own and needs a hand from diet-derived sources. Citrus fruits are brimming with the nutrient, as are peppers, strawberries, broccoli, and Brussels sprouts.
gresei // Shutterstock
- Key nutrient: Allicin
Aromatic foods are not only delectable culinary additives, but they also contain potent compounds that, among other benefits, support immune health. Garlic is particularly effective due to a sulfuric compound called alliin. Upon being crushed, cut, or bit, alliin becomes allicin, the source of garlic’s pungent bouquet, as well as its immune system-supporting benefits.
Garlic is a parallel play type of immune support with natural antimicrobial activity and substantial concentrations of sulfur compounds, which are recognized as a powerful part of immune system maintenance. It’s also been found to have protective effects when confronted with conditions that harm the immune system such as cardiovascular disease, cancer, blood pressure conditions, and diabetes.
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- Key nutrient: Probiotics
Gut health affects more than just smooth digestion; it impacts the body as a whole. The delicate balance of healthy and harmful bacteria in the gastrointestinal tract is a determining factor of the stability and health of the immune system. Using probiotics—live microorganisms that create healthy gut microbiota—balances your gut’s ecosystem, nutritionally enhances your diet, and improves overall health—all factors that affect your immune system.
Naturally derived probiotics, which are named for their specific genus, species and strain, are found in several fermented plant-based foods. These foods include miso, natto, sauerkraut, pickles, and kimchi. Probiotic supplements are also a popular and effective option.
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- Key nutrient: Vitamin B6
If you’re looking for a reason to splurge on avocado toast, here’s a pretty good one: That delicious, nutrient-dense avocado is supporting your immune system. Vitamin B6, most notable for using and storing energy and creating red blood cells, is also necessary for immune system function by producing antibodies and cytokines.
One avocado contains around 4% of your daily value of vitamin B6 making this versatile food an excellent source of healthful benefits. In addition, that slice of avocado toast provides vitamin C, vitamin A, folate, copper, and zinc, all key nutrients for immune system support.
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- Key nutrient: Copper
Whole grains are an almost complete package of nutrients and one of the best plant-based sources of copper. Copper, an often forgotten nutrient, supports the immune system in two major ways: It helps immune cells produce energy and protects immune cells. Copper’s impact on the immune system is most clearly seen in cases of severe copper deficiencies, which manifest as impaired immune function.
Whole grains are fairly diversified and complementary to almost any palate, and even gluten-free diets as well. Even better, there’s really no superior option, simply those with differing levels of copper, such as buckwheat with around 100% of your daily value or wild rice, oats, and quinoa with closer to 20%.
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- Key nutrient: Folate
Legumes top the list when it comes to nutrient-dense foods that support the immune system thanks to their folate content.
Folate, also called vitamin B9, is an important part of your body’s most intimate makeup—DNA and genetic material creation, dividing of cells, and protein synthesis. A folate deficiency affects the immune system by decreasing circulating T cells, which are cells that protect the body from infection, and blocking your body’s ability to fight infection.
Getting enough folate is an easy feat for anyone who loves legumes. Beans, peas, and lentils are loaded with folate and offer a great source of other immune health-supporting nutrients including B vitamins and copper. To add to the pot, legumes are an excellent source of fiber, which is necessary for a healthy gut and directly correlates to the stability of your immune system.
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- Key nutrient: Selenium
Among the list of overlooked nutrients is selenium. As a trace element, the body doesn’t need much of the mineral, but those small amounts are essential for a healthy immune system. Selenium is part of the system that protects our bodies from oxidative damage and infection. Brazil nuts are the best plant-based source of selenium. One nut contains around 91 micrograms of this key nutrient, meaning that four or five nuts meet the higher end of the daily recommended allowance.
The Bertholletia excelsa tree in the Amazon jungle consumes inorganic forms of selenite and selenate from the soil, converts them into selenium, and deposits the mineral into the seeds called Brazil nuts. These decadent, creamy nuts are also rich in antioxidants, phenolics and flavonoids, all of which reduce inflammation that can reduce the risk of immune system-harming conditions.
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- Key nutrient: Zinc
Nuts and seeds are nutrient-dense morsels that make an enriching addition to an immune system–supporting diet. They are rich in antioxidants, which help reduce inflammation; fiber, which feeds healthy gut bacteria; and the minerals copper and selenium, which are directly attributed to healthy immune system function.
Yet, most importantly, nuts and seeds are an excellent source of zinc, which helps the immune system respond to infections, aids natural killer cells, and fuels the development of T cells. A zinc deficiency lands a hard blow to immunity by negatively affecting antibody responses, cytokine production, and even reduces bone marrow–based T cell production.
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- Key nutrient: Vitamin A
When it comes to greens, the darker the hue and more bitter the bite, the better for your immune system. These plants are rich in vitamin A, which is directly related to immune system health. Vitamin A is part of the signaling process for the reproduction of T cells and plays a key role in the balance of T helper cells, which help immune responses.
Most dark leafy greens are superfoods thanks to vitamins and minerals that help fight inflammation and add nutrient density to any meal. Both kale and spinach are the richest in vitamin A.
Gaus Alex // Shutterstock
- Key nutrient: Vitamin D
Vitamin D, the sunshine vitamin aptly named for the synthesis that takes place when ultraviolet rays hit the skin, exploded into mainstream popularity during the coronavirus pandemic. Yet, vitamin D has always been known to play an important role in both immune system health and inflammatory responses.
Mushrooms are the only unfortified, plant-based food source of vitamin D. Even with that said, mushrooms have to be exposed to ultraviolet light during growth to contain levels of vitamin D helpful to the human body. Those richest in the vitamin are ultraviolet light-exposed raw crimini, brown, white, portabella, and maitake mushroom varieties. It’s important to note mushrooms alone don’t provide enough vitamin D, therefore additional supplementation is recommended.
This story originally appeared on Thistle and was produced and distributed in partnership with Stacker Studio.
Joe Carrotta/NYU Langone Health via AP
In this September 2021 photo provided by NYU Langone Health, a surgical team at the hospital in New York examines a pig kidney attached to the body of a deceased recipient for any signs of rejection. From left are Drs. Zoe A. Stewart-Lewis, Robert A. Montgomery, Bonnie E. Lonze and Jeffrey Stern. The test was a step in the decades-long quest to one day use animal organs for life-saving transplants.
Joe Carrotta/NYU Langone Health via AP
In this September 2021 photo provided by NYU Langone Health, a surgical team at the hospital in New York examines a pig kidney attached to the body of a deceased recipient for any signs of rejection. The test was a step in the decades-long quest to one day use animal organs for life-saving transplants.