How to mass produce meat with immortal stem cells

2023-05-12 11:31:33

At Tufts University they have developed immortalized bovine muscle stem cells (iBSCs) that can grow rapidly and divide hundreds of times, even indefinitely.

To make it possible for cellular livestock, the process of growing meat in bioreactors, to feed millions of people, several technical challenges will have to be overcome.

It will require growing muscle cells from chicken, fish, cows, and other food sources to produce millions of metric tons per year.

With this objective, the investigation of the Tufts University Center for Cellular Agriculture (TUCCA) ⁽¹⁾described in the magazine ACS Synthetic Biology ⁽²⁾means that researchers and companies around the world can access and develop new products without having to repeatedly obtain cells from farm animal biopsies.

Cell-cultured meat production will require muscle and fat cells with a very high capacity to grow and divide. While cell-cultured meat has garnered media attention with examples such as the US FDA’s preliminary approval of cultured chicken and even a mastodon DNA-cultured hamburger, the products are still expensive and hard to scale up.

Maintain “youthful” chromosomes

Normal muscle stem cells taken from live animals to start a culture typically divide only about 50 times before they begin to age and are no longer viable. While it is theoretically possible for these stem cells to produce a substantial amount of meat, the immortalized cells developed by the TUCCA team offer several advantages. One is the possibility of producing significantly more mass for meat production.

Another advantage is that by making immortalized cells widely available, they will lower the barrier to entry for other researchers to explore cell agriculture, finding ways to reduce costs and overcome challenges to increase production.

“Usually, researchers have had to do their own isolates of animal stem cells, which is expensive and time-consuming, or use model cell lines from less relevant species, such as mouse muscle cells,” said Andrew Stout, a student at TUCCA postgraduate and project lead investigator, “Using these new persistent bovine cell lines, your studies can be more relevant, literally getting right to the heart of the matter.”

Two steps were key to transforming regular bovine muscle stem cells into immortalized bovine muscle stem cells. Most cells, as they divide and age, begin to lose DNA at the ends of their chromosomes, called telomeres, like worn ropes that fray with use. This can lead to errors when DNA is copied or repaired. It can also cause gene loss and eventually cell death.

The researchers engineered the bovine stem cells to constantly rebuild their telomeres, effectively keeping their “juvenile” chromosomes ready for another round of replication and cell division.

immortalize cells

The second step in immortalizing the cells was to have them continuously produce a protein that stimulates a critical stage of cell division. This effectively speeds up the process and helps cells grow faster.

Muscle stem cells are not the final product one wants to eat. They must not only divide and grow, but also differentiate into mature muscle cells like, or at least very similar to, the muscle cells we eat in a steak or steak. Stout and his research team found that the new stem cells did differentiate into mature muscle cells, although not quite identical to animal muscle cells or muscle cells from conventional bovine stem cells.

“It’s possible that they’re mature enough to replicate the flavor and texture of natural meat,” Stout said, “That’s something we’ll have to explore further. They’re doubling at a very fast rate, so it’s possible that they need a little more time to reach full maturity.

“While some may question whether it is safe to ingest immortalized cells, in fact, when the cells are harvested, stored, cooked and digested, there is no viable path to continued growth,” said David Kaplan, a Stern Family professor. in biomedical engineering at Tufts and director of TUCCA. “Like the natural meat we eat today, the cells are simply turned into inert material that we hope will taste delicious and provide a wide range of nutritional benefits.”

References

• ⁽¹⁾ New Cellular Agriculture Consortium Will Help Develop the Foods of the Future. Tufts University Center for Cellular Agriculture (TUCCA).
• ⁽²⁾ Immortalized Bovine Satellite Cells for Cultured Meat Applications. ACS Synthetic Biology.