Cows are important to John Mortimer. From his home in Dallas Center, IA, he coordinates the Cattlemen’s Beef Quarters at the Iowa State Fair, an enterprise that uses volunteer labor from 70 county cattlemen’s organizations to serve beef to more than 70,000 people each year during the 10-day summer festival.
And with every beat of his heart, blood travels through a bovine pericardial valve.
It was early 2010 when Mortimer was diagnosed with an aortic dissection. During the surgery to repair the artery with a fabric patch, doctors discovered a bad valve, and replaced it with a bovine valve.
“I had no part in the decision and they had no idea of the connection,” Mortimer says. “It was just fate, I guess.”
Mortimer’s surgeon, Robert Schneider, MD, and his partners, perform 50-70 of the procedures each year at Iowa Methodist Medical Center in nearby Des Moines.
“The advantage of the bovine valves over mechanical ones is that barring no other complications, the patient doesn’t require blood thinners,” Schneider says. The valves are crafted from a sheet of pericardium (heart sac) cut into leaflets, and attached to a cloth and metal framework. The first models made in the 1970s and ’80s weren’t very hemodynamic (meaning they took up too much space and restricted the flow of blood). But in the 1990s, Edwards Life Sciences improved the design, Schneider says, and he’s used them ever since.
Schneider says rejection isn’t an issue since there’s no live protein. Plus, infection risks are low, basically equal to mechanical versions, though mechanical versions are more durable. The bovine valve has a typical lifespan of 15-20 years.
W&G Marketing Co., Inc. is based in Ames, IA, and “harvests” medical tissue as it processes beef for its specialty meat business.
“It’s not a new field,” says Marvin J. Walter, board chairman for W&G Marketing, which also collects porcine tissue. “Both are better than synthetic,” he says. W&G Marketing performs the initial tissue collection and then sells the product to a company that processes it for medical use.
“From a business perspective, it’s important to do it in a volume that makes it worthwhile. For many, it’s too small of a piece of the business,” he adds. W&G Marketing makes the effort pay by producing a variety of bovine, porcine and rabbit products like vascular segments, valves and blood products; shipping daily to ensure freshness.
Bovine vascular grafts are used for hemodialysis patients, and Schneider says he’s used pericardium sheets to repair tears in the heart from traumatic injury.
W&G Marketing also harvests whole hearts and heads for research and teaching purposes. “It really is true that everything is sold but the moo,” Walter says.
“Certainly there’s a long history of producing pharmaceutical products from cattle,” says David Faber, president of Trans Ova Genetics in Sioux Center, IA. “Products like epinephrine, insulin, ACTH – a pituitary gland extract; both adult and fetal calf serum are important for research.” Fetal calf serum is used for in vitro cell culture because of its low level of antibodies and versatility.
Sioux Pharm Inc., also in Sioux Center, is the largest producer of arthritis treatment chondroitin sulfate in the U.S. Chondroitin sulfate is a nutriceutical, not technically a pharmaceutical, as is trypsin, an enzyme used to degrade protein, also produced by Sioux Pharm.
“We produce and isolate chondriotin sulfate from bovine trachea,” says Allan Kramer, PhD, Sioux Pharm’s president. Sioux Pharm uses half of all the bovine tracheas produced from all of the major slaughterhouses in the U.S. He says the drug not only relieves pain, but lubricates the joint and helps rebuild cartilage.
“It’s basically a natural substance that replaces what the body has stopped making,” Kramer explains.
At the University of Connecticut, renowned orthopaedic surgeon Cato T. Laurencin, MD, PhD, utilizes xenotransplantation (the transplantation, implantation or infusion of non-human cells, tissues, or organs into a human recipient) for bone, cartilage and tendon repair.
According to the American Academy of Orthopaedic Surgeons (AAOS), this approach is gaining in popularity “because the demand for all types of organs and tissues far outweighs the supply.”
Tailoring the supply
An industry leader in cloning, Trans Ova assists companies like Hematech, Inc., in producing animals to meet specific medical and research needs. “We can genetically engineer a cow to produce a pharmaceutical protein,” Faber explains.
The implications are numerous, according to Faber. Albumen, a major component of blood protein, can be made from cows as well as humans. Cows can be also be engineered to produce antibodies that combat viruses and even snake-bite venom.
Hematech is working to develop genetically altered cattle that can produce human antibodies for treating antibiotic- resistant infections, immune deficiencies, autoimmune diseases and transplant rejection.
“This is especially useful for troops in the field combating bio-warfare, where they don’t have time to build the antibodies,” Faber says. The Department of Defense and the National Institutes of Allergy and Infectious Disease are funding Hemetach research that is developing antibody therapeutics for botulism toxin, anthrax and smallpox exposure.
Research and development in cattle cloning also offers implications for human medicine.
“Cloning in its simplest form is reprogramming a cell from its differentiated adult form back to a cell with total potential to develop to any cell type found in the body,” Faber says. “If we can understand this process, then we can gain valuable insight in many areas of research including cancer, aging, and cell therapy.”
There are skeptics
“With bovine-derived pharmaceutical products, there is some industry concern with cattle diseases such as BSE,” Faber says. “There is great promise and application for bovine products, and we have the ability to manage the issue.” Cows used by Trans Ova are housed and segregated on special farms. “There’s no intent for them to ever have anything to do with beef production. They’re ‘pharm’ animals, not farm animals.
“It’s more of a perception problem,” he continues. “Just like there was concern not that long ago with dried human-derived blood products and AIDS.” He adds that, with proper management, cows are a perfectly safe, and many times, the only option for producing certain products. “You can’t vaccinate cells and have them produce antibodies. You need a living, breathing animal.”
Laurencin is one of those concerned about disease transmission. In an interview published by the OOAS, the orthopedic surgeon says he would expand the information required by the Food and Drug Administration to include animal and herd-health management; whether or not the herd was closed; isolation of harvested material from that of other animals; and age and source verification.
Those on the supply side say every precaution is taken to ensure safety.
Sioux Pharm has all animals inspected by a veterinarian and adheres to U.S. Pharmacopeia standards that “set the industry standard for purity and strength,” Kramer says.
W&G Marketing relies on USDA inspection and vet oversight. Any domestically produced animal that meets USDA Food Safety Inspection Service standards for consumption through pre- and postmortem inspection, is a potential candidate for medical material harvest. There are strict harvesting protocols for cleanliness and sanitation that include proper attire – boots, socks and covering of all hair, even facial hair, and utensil sanitation. And W&G Marketing’s program is under the direct supervision of a company-employed veterinarian with expertise in the field.
“It’s important to have people do this who understand biosecurity,” Walter says. Walter adds that while there are currently no source-verification standards in place for the products harvested for use in the U.S., there are for those shipped to other countries.
Having a bovine valve doesn’t bother John Mortimer a bit. “I’ve been involved with beef for so long, it’s never scared me,” he says. “It works great. I feel great. But, yes, it is interesting.”