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Stem Cell Flambé: Test-Tube T-Bones on the Horizon Say Researchers

A world which is free of caged chickens, slaughterhouses and avian flu is possible, researchers claim. All that’s needed is labaratory-made meat. While test-tube T-bones are still the domain of futurists, scientists have already taken the first important steps.

The frog steaks were sautéed in a garlic and parsley sauce, then garnished with chives. When the feast was finally ready to eat, the artists sat down for dinner at the museum.

Two years ago, at an exhibit in the French city of Nantes titled “L’Art Biotech,” Oron Catts, Ionat Zurr and Guy Ben-Ary dined on “tiny polymers stuffed with clawed frog cell à la Davis, flambéed with Calvados.” The artists, part of the Australian “Tissue Culture Art Project,” called their installation “Disembodied Cuisine.” They had mounted tissue cells from frogs onto small biopolymer substrates — about three centimeters in diameter — and watched as they grew into small “steaks.” The four frogs from which the tissue had been taken looked on from a nearby aquarium.

The purpose of the project was to probe the boundaries between the living and the “semi-living,” while at the same time creating “victim-free meat” — meat that doesn’t require the slaughter of a single animal. The comical biotech installation was meant to “disturb,” says Catts. But real life could one day be just as disturbing. The vision of frog-friendly frog legs could soon become reality.

And it’s not just frog meat that may soon be jumping from Petri dishes onto your plate. Laboratories, some hope, may someday replace slaughterhouses and even now, researchers are working feverishly to pull steaks and hamburger out of their pipettes. Their goal is the development of giant bioreactors where butcher shop wares are grown out of cell cultures, potentially forever relegating mass-production chicken farms, veal calf production and pigsties to agriculture museums. One day, say some scientists, meat incubators could become standard kitchen equipment, allowing consumers to grow their own liver pâté and meat balls, turkey sausage and smoked salami.

“Animal products without animals”

“The technology already exists for making a sort of pressed chicken in the laboratory,” says agriculture economist Jason Matheny of the University of Maryland. Researchers in the Netherlands are even studying ways to take the next step — from laboratory meat to industrial production. The Dutch Ministry of Economic Affairs has earmarked €2 million for a four-year research project at universities in Eindhoven, Utrecht and Amsterdam. The project is being co-sponsored by the meat-processing industry, which has kicked in another €2.3 million.

“We’re trying to develop animal production without animals,” says cell researcher Henk Haagsman, director of the research group in Utrecht. At this point, he says, researchers still haven’t figured out whether laboratory meat can be produced inexpensively enough to compete with traditional meat. “But from a scientific perspective,” says Haagsman, “the sky is the limit when it comes to meat production in the laboratory.”

The basic concept behind what is known as in vitro cultivated meat sounds surprisingly simple. Meat is mostly made up of bundled muscle cells, interspersed with fat and connective tissue cells. If it were possible to grow these cells in the laboratory and combine them at the right ratios, test-tube meat could become a reality. The patent that serves as the basis for the Dutch research project puts the issue succinctly: “The product has the structure and flavor of lean meat, but without requiring animals to suffer and without involving religious and ethical concerns or causing environment problems, all of which are the case in today’s meat production.”

As promising as this may sound, biotech meat production still has many hurdles to overcome. Scientists are just now beginning to experiment with ways to reconstruct knuckles of veal and pig stomachs in the laboratory. Three years ago, US researcher Morris Benjaminson of New York’s Touro College was one of the first to experiment with the concept of growing filets in a Petri dish. After placing tiny muscle particles taken from goldfish into a nutrient solution, he observed how the muscle tissue grew by up to 14 percent within a week.

Fetal calf serum gravy

He then presented the thumb-sized results, in fresh and sautéed form, to a jury. “The smell and appearance corresponded to that of supermarket fish,” says Benjaminson. The only problem was that no one was interested in eating his fish nuggets, perhaps because his tiny goldfish filets matured in something called fetal calf serum.

This nutrient medium, derived from cow fetuses, is prized in biology labs all over the world as extremely effective in growing cells. But it’s hardly suitable for use as a culture medium in food production, partly because it’s a potential source of the prions that cause Mad Cow Disease (BSE) and partly because it’s prohibitively expensive. Matheny estimates that a kilogram of laboratory meat would cost about half a million dollars if it were grown in calf serum.

In order to make faux meat a reality, then, one of the first tasks is to develop an inexpensive ersatz nutrient solution from plants or mushrooms. Maitake mushrooms, for example, have already proved to be a possible alternative.

One additional step, though, needs to be taken to achieve the dream of meat production entirely without animals. In his pioneering experiments, Benjaminson was still using real goldfish as the starting material for his cultures. But experts now believe they can create flank steak wholly without the flanks. The key? Cells called myoblasts, the non-differentiated precursors to all skeletal muscle cells. Tiny myoblasts are capable of dividing at a tremendous rate. If conditions are right, they ultimately combine and mature into the muscle fibers that characterize meat. “Only when myoblasts fuse does muscle tissue develop, leading to the meat structure we are familiar with,” explains cell researcher Haagsman, who is currently studying the process in pigs. He adds that certain growth factors, electromagnetic fields and a sort of cellular muscle-building are necessary to encourage the cells to fuse. Otherwise, he says, “you get nothing but cell paste.”

Scientists are already concocting methods to conduct in vitro muscle development on an industrial scale. Matheny, for example, proposes using large support membranes made of edible collagen as a substrate for the cell strains. If the frames were stretched at regular intervals, Matheny theorizes, they would pull apart and essentially train the muscle fibers growing on them. As soon as the wafer-thin sheets of muscle material reached maturity, they could be harvested and processed into meat products.

Tissue expert Vladimir Mironov of the Medical University of South Carolina has another elegant idea. His plan is to encourage myoblasts to grow on small spheres that expand and contract in respond to changes in temperature. The muscle tissue could then develop on the slowly pulsating spheres in rotating bioreactors filled with nutrient solution. Mironov’s plan also calls for harvesting the tissue balls and then processing them further, into poultry nuggets, for example. Mironov has already produced small amounts of turkey meat using a similar approach.

Artificial blood vessels

Nevertheless, the results of cellular bodybuilding are unlikely to live up to the standards of gourmet cooking. “We’re still a long way from juicy steaks,” Matheny admits. The problem, he says, is that not all cells can be supplied with nutrient solution in a filet-shaped tissue base. The laboratory muscle tissue would have to be permeated with blood vessels, so that muscle cells as well as fatty and connective tissue could adhere to these vessels. These types of tissue cultures have already been developed in medical research. Scientists at the Massachusetts Institute of Technology (MIT), for example, recently grew skeletal muscle tissue that develops its own blood vessels in the laboratory. When they were transplanted into the muscles of mice, a few of the blood vessels grown in the laboratory actually adhered to blood vessels in the mouse body, and then supplied the implanted tissue with nutrients.

It’s a technology that may one day be used to repair the heart muscles of heart attack patients. But as a technology for creating artificial sirloins and chicken nuggets, it is probably not suitable, says Haagsman. “This kind of approach can only work in medicine,” he says. “It’s far too expensive and therefore virtually unusable in large-scale meat production.”

All of which means that the world may have to wait a few more decades before the perfect flank steak emerges from a counter-top kitchen incubator. Nevertheless, the disciples of the Petri dish are firmly convinced that the technology will establish itself sooner or later.

“The benefits for animal protection, the environment and our health are obvious,” says Matheny. He envisions an age free of large-scale animal farming with a concurrent elimination of disease risk and animal waste problems. “Meat grown in cultures doesn’t need pastures or stables, doesn’t need drugs and doesn’t contract BSE or avian flu,” he says. Matheny believes that astronauts and soldiers could be the first target group for laboratory meatballs. He even has plans to tweak the ingredients in the future: “We could make meat healthier, for example, by replacing saturated with unsaturated fatty acids.”

Test-tube sausage is also likely to be popular among many vegetarians, especially as the culinary quality of laboratory meat is presumably similar to that of tofu cubes. Despite researcher Mironov’s claim that “the taste of meat depends on the fat; we can simply add fat cells to create taste,” the culinary delights of laboratory meat are not exactly earth-shattering at this point. The “ultimate nouvelle cuisine” created by the “Tissue Culture Art Project” artists in Nantes ultimately proved to be a flop.

Bio-researcher Catts reported that the frog steak was gelatinous, and the substrate had the consistency of material.

And the taste? “The sauce was good.”

Translated from the German by Christopher Sultan

–> read original story at SPIEGEL Online International

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