Imagine a Mizzou football game day at Faurot Field. The stands of Memorial Stadium are filled to absolute capacity, brimming with a sea of tigers bedecked in black and gold. This crowd of more than 70,000 football fans, an enormous mass of humanity gathered in one place, would still be outnumbered by the body of Americans whose game clocks on life are running out — candidates for organ transplant.
A staggering 79,435 individuals are active candidates for organ transplant in the United States. In the time that it would take to play a college football game, that number would grow by 20 individuals in need of a life-saving organ donation.
Science is tackling the challenges of treatment and transplantation for a host of medical maladies, from severe burns to renal failure. Researchers at the University of Missouri National Swine Resource & Research Center (NSRRC) might have found the answer in real pigs’ skin, and lungs, eyes, hearts and veins, to name a few.
The NSRRC, created in 2003, produces a catalog of genetically engineered swine models for use in biomedical studies. The center is comprised of a team of researchers and professionals in genetics, porcine reproduction and physiology.
According to Randall Prather, a professor in the Division of Animal Sciences and a principal investigator at the NSRRC, the pig is uniquely suited for biomedical research. The size and structure of swine organs and the similarities between hog and human physiology allow researchers to develop more effective responses and technologies to human health concerns.
“The genotype (of a pig) is about three times closer to a human’s than a mouse’s,” Prather said, in reference to another animal species commonly used for biomedical research.
The similar immune responses of pigs and people are also a benefit of using the hog as a biomedical research model for studying disease.
“When you challenge a pig with a foreign molecule, the genes that turn on in response are more similar to the genes that turn on in humans, as compared to the mouse,” Prather said.
For the thousands of Americans awaiting an organ transplant, a solution to what is often a risky medical procedure — up to 12 percent of kidney transplants fail within the first year — might seem as likely as pigs taking flight. Although pigs developed by the NSRRC do not fly, many of them do have a miraculous potential to deliver future antidotes to this and a host of other human health concerns.
Researchers at the NSRRC genetically engineer swine by knocking out genetic qualities, such as the sugar molecule that inhibits organ transfer between swine and humans, and introducing mutations, including one that elicits the symptoms of cystic fibrosis as they would appear in humans.
By manifesting certain genetic traits in swine and disabling the effects of others, the researchers produce more effective swine models for eventual use in biomedical applications.
According to Prather, in a hog-to-human transplant situation, human antibodies would recognize and attack a sugar molecule found in hog cells, causing a hyperacute rejection response. Blocking the molecule, known as the GGTA1 sugar linkage, in swine through genetic engineering removes this response. With the ability to disable this molecule, xenotransplantation, the transfer of cells, tissues and organs between species, may shorten the nation’s transplant waiting list while lengthening the lives of waitlisted patients.
The breadth of research conducted with the NSRRC’s genetically engineered swine reflects the hog’s versatility as a physiological model, contributing substantially to the international body of medical knowledge.
Medical researchers across the globe use everything but the oink of NSRRC swine — from stem cells to skin tissue.
“We send umbilical cords and stem cells to Kansas State, skin to Calgary, testicles to Saskatchewan, neural stem cells to UC Irvine and Pittsburgh, and cardiac stem cells to Pittsburgh,” Prather said.
Prather added that researchers apply biomedical technologies, develop medical devices and test remedies for diseases by using the unique genetic qualities of these swine resources.
Studying the influences of chronic disease has become easier with the help of genetically engineered hogs. Through gene disruption, hogs have been developed that simulate the acute effects of cystic fibrosis — a life-threatening genetic disorder. Hogs with the disrupted genes exhibit a more accurate simulation of human cystic fibrosis symptoms, from liver lesions to bile and pancreatic duct blockages. Therefore, researchers are better able to assess the effectiveness of potential treatments.
Biomedical researchers and hospital patients aren’t the only individuals who benefit from the technology behind the genetically engineered swine at the NSRRC. Animal science students at the University of Missouri help care for the pigs, learning the importance of the animals as they provide meticulous care.
Rachel Shuey, a Pre-Veterinary Scholar and sophomore animal science student from Moore, Oklahoma, is a hog caretaker at the NSRRC. She assists in delivery and processing of piglets and helps maintain the cleanliness of the animal care facilities.
As a student with in interest in veterinary science, Shuey sees an overlap in the futures of animal science and medical science.
“Veterinarians understand a lot about how animals will react to certain health concerns,” Shuey said. “Seeing as these pigs react similarly to humans, veterinarians can then work with human doctors to determine a plan or administer certain drugs to help fix diseases.”
Genetically engineering swine might have seemed like science fiction 20 years ago. However, 20 years from now, organ donation and medical applications stemming from NSRRC research could become standard practice.
Garrett Wilt, a junior biochemistry major from Blue Springs, Missouri, is planning a career in the medical field. Wilt believes that with patience, hog-to-human transplant technology may emerge as a lifesaver for patients.
“With the possibility of a hog-to-human transplant, the timeline on treating patients is much improved, the success rate of transplantation goes up dramatically, and the transplant procedure becomes more cost-effective,” Wilt said.
As the medical potential of genetically engineered swine continues to emerge, patients facing health challenges and disease may find hope in hogs that produce more than cured ham — ham with a cure.