Vladimir Mironov, head of the Medical University of South Carolina’s (MUSC) Shared Tissue Engineering Laboratory, has proposed the development of a method to grow steak from cell culture for space missions. NASA turned down his grant. The reason given for rejecting the grant application is that astronauts can do fine on protein pills. How unimaginative. Space exploration should be conducted in ways that maximize the fun and innovation. Mironov could still turn to the big fast food companies for funding. Imagine Burger King, McDonalds, or Wendy's patties grown to the exact needed shape.
One problem that meat cell growth faces is the need to exercise the growing muscle cells to develop the ideal texture.
He suggests using a bioreactor with a branching network of hundreds of tiny edible tubes that act like artificial capillaries to convey nutrients to the growing meat. But to satisfy those who crave the texture and mouthfeel of a good steak, you need to develop something that mimics the texture of real meat.
That means generating a complex structure of muscle and connective tissue, and to do that, the muscle myoblasts need to stretch and contract regularly. In other words, not only must you feed your steak well, you have to give it plenty of exercise too.
The article mentions a vegan student who wanted to take a biopsy of her own tissue and then culture it to make self-steaks that would allow her to eat meat without feeling that she killed an animal. Of course, if one took a biopsy from a cow and grew a steak its not like one would have to kill the cow in order to get meat either. Still, perhaps you taste good. Since it will probably be no harder to grow human muscle tissue than to grow cow muscle tissue this could become quite a popular thing to do for anyone who doesn't find the idea of eating their own tissue to be nauseating (makes me queasy just thinking about it).
Mironov's main interests appear to be the growth of cardiovascular replacement tissues
Perfusion Bioreactor with Circumferential and Longitudinal Strain of a Tubular Construct for Accelerated Tissue Engineered Vascular Wall Histogenesis
Department of Cell Biology and Anatomy
Medical University of South Carolina, Charleston
A bioreactor is a key element of cardiovascular tissue engineering technologies. Increased use of stem cells as a cell source in cardiovascular tissue engineering is transforming this field into an in vitro approach that seeks to accelerate recapitulation of in vivo embryonic vascular development. The purpose and goal of existing bioreactors are to provide the pulsatile flow through an engineered construct and thus to generate periodic radial distension (circumferential strain) of the vessel wall. The important mechanical element of embryonic vascular development is longitudinal strain associated with arterial longitudinal growth. Thus, in order to "biomimic" the embryonic mechanical vascular environment (EMVE), perfusion bioreactor must also include the functional capacity for longitudinal strain. To accomplish this, we have developed a novel perfusion bioreactor. This bioreactor was designed and fabricated to provide the simulation of the EMVE including capacities for both circumferential and longitudinal strain of cardiovascular engineered tubular constructs. Results indicate this new bioreactor can provide the new critical component of biomechanical conditioning which is essential to mimic EMVE and accelerate vascular wall histogenesis.
Mironov points out that the discovery of stem cells (and by this he means non-embryonic stem cells that are found in adult organisms) has greatly increased the prospects for tissue engineering.
“Anatomy is no longer a static science,” Mironov said. “The discovery of stem cells has reinvented a classical microscopical anatomy—a tissue biology science, which is now again a vibrant, booming discipline. It no longer considers tissue a static, solid structure, but rather as elastoviscous, constantly renewing its dynamic community of cells and extracellular matrix.”
In the labs and on the near horizon are perfusion and bioengineering techniques to keep transplant organs alive and fresh longer, procedures to shrink a malignant tumor by blocking its blood supply, and plans to grow human organs with the careful manipulation of stem cells.
The growth of muscle tissue for human consumption is relatively easy as compared to its growth for medical applications. Quite a few scientists working on that harder problem. Here's a discussion by UCLA graduate student Carrie Caulkins on the problems that need to be solved to grow muscle tissue to replace damaged, diseased, or aged muscle.
One of the main focuses of the Tissue Engineering Department at UCLA is the design and fabrication of highly porous tissue engineering scaffolds with novel material formulations to control cell-substrate, cell-cell, and cell-signal interactions.
Future challenges in polymer scaffold processing include the development of fabrication techniques that will allow manufacturing of high-strength scaffolds for hard tissue replacement at load-bearing sites, and the ability to incorporate and deliver growth factors into scaffold construction, without loss of growth factor activity. This challenge likewise affects the cellular and signaling aspects of tissue engineering, and prompts the need for more research on cell-cell interactions and the chemical and protein signaling involved.
Once the harder case of muscle or organ growth outside of a living organism has been solved for medical purposes the ability to do it for food production will be trivial by comparison. Therefore it seems reasonable to expect the easier problem of growing cells for meat consumption will be solved as well. When that technology becomes really mature we'll be able to buy home meat growing devices just as we can today buy home bread makers.Herman Vandenburgh of Brown University is working on modelling the effects of gravity on muscle development.
For Vandenburgh, the primary goal of his space research is developing pharmaceutical countermeasures to prevent the muscle wasting that occurs in space, "helping man explore a new environment, and a very hostile environment at that." His research group has developed a tissue culture system for preliminary tests of these countermeasures. "It's really the classical way of doing these types of experiments," he said, "You first test out new drugs in tissue culture, on cells outside the body, and then the next set of experiments are in animals. You hope you see a similar type of effect as you saw in cell culture. Then you go from animal to human. At each stage you have to hope that what happens early on is going to follow through. It's much more difficult to predict what's going to happen if you go right into doing animal studies."
While Vandenburgh is interested in solving this problem for astronauts this work might also be useful for growing meat in a cell culture. Recall that the first article above mentioned the problem of exercising the growing muscle tissue. Exercise and gravity both affect how muscle cells grow and organize themselves. so any attempt to solve those problems for human health will provide useful information for how to grow more realistic steaks.
Robert G. Dennis, Ph.D., University of Michigan Biomedical Engineering Assistant Professor, and member of the U Mich and MIT Biomechatronics (cool word, no?) Groups, lays out his tissue engineering Vision for the Future
Imagine the technology to seamlessly integrate hybrid prosthetic devices with their human users. Instead of bulky and ineffective synthetic mechanisms, prosthetic devices could have tissues integrated directly into them. One of our primary objectives is to integrate living muscle actuators into prosthetic devices. As the art and science of tissue engineering evolves, so too will the hybrid prosthetic devices, incorporating a greater percentage of more sophisticated engineered tissues, until the device eventually becomes fully biologic. We are working on the technology to grow the engineered tissues from small samples of the native tissue of the user, so that when complete the engineered prosthetic device will be fully compatible with the user, employing no foreign biological elements.
Imagine engineered tissues that can fully replace injured tissue, or be used for the surgical correction of congenital deformity.
Imagine the end of animal testing. New drugs and surgical procedures will be tested directly on engineered tissues. Tissues will be grown from small samples of cells without requiring animals to be killed. New drugs and procedures can be tested on human tissues that are engineered in culture, eliminating the cost and clinical uncertainty of animal testing.
Imagine engineered meat as a food source, eliminating the need for raising and slaughtering livestock.
Imagine a world with living computers, robots, and other devices, that operate silently and efficiently, are fault tolerant and can heal themselves, can adapt to their environment, are energy efficient, produce no harmful byproducts, and are 100% biodegradable. Humans will be able to interact with their creations in ways never dreamed possible.
Imagine the day when clattering, inefficient, synthetic electro-mechanical contrivances seem quaint and frivolous. From the first time that a proto-human grasped the first stone tool and used it to shape the environment, the use of living tissues as tools has been set in our destiny.
This is a future that most of us will live long to see. Tissue engineering will allow the reversal of aging of many parts of our bodies by replacement with newer and even better and longer lasting parts.
Robert G. Dennis say there are only three groups in the world working on engineering functional skeletal muscle.
The State of the Art in Functional Skeletal Muscle Tissue Engineering can be easily summarized by first defining the function of skeletal muscle. Though muscle tissue performs many functions for the body, some arising from the emergent properties of muscle cells organized into whole muscle organs, such as heat generation and protein synthesis, the most basic definition of muscle tissue function is the generation of controlled force, work, and power. It is necessary to quantify the contractility of the muscle tissue, to organize the tissue in such a way as to promote the generation of directed force, and exert control over the contractions for research in this area to be considered engineering, rather than cell biology. After all, spontaneous contractions in cultured skeletal muscle cells were first reported in 1915 (Lewis), and this was not construed as 'engineering'. Defining Functional Skeletal Muscle Tissue Engineering in this way, it is possible to assert that at this time there are only three research groups in the world engineering functional skeletal muscle in vitro: Herman Vandenburgh and Paul Kosnik in Providence, RI; myself and Hugh Herr at MIT, and the Muscle Mechanics Laboratory at the University of Michigan.
Update: Some Chinese eat aborted and stillborn babies. I'd excerpt from it but its too disgusting.
Update II: More on cannibalism in China. Not for the faint of heart.
|Share |||Randall Parker, 2003 January 01 02:02 PM Biotech Organ Replacement|