Thanks to genetic modification of cow embryos, the mammal can produce human insulin in its milk. This could make it easier for people with diabetes to access this hormone.
- Researchers have genetically modified cow embryos by inserting a segment of human DNA: the latter codes for a precursor of insulin called proinsulin.
- The cow born from this experiment produced proinsulin in its milk and even insulin directly.
- For researchers, this could one day become a new insulin resource, necessary for people with diabetes.
Are cows the future of diabetes care? This is the theory developed by a team of American and Brazilian researchers. These scientists, from the universities of Illinois Urbana-Champaign and Saõ Paulo, have discovered a new way to make insulin, necessary for people with diabetes. Genetically modified cows are able to produce the hormone in their milk.
Why might we need cows to produce insulin?
In the scientific journal Biotechnology Newspaper, the authors point out that the demand for insulin is increasing. “Diabetes is one of the fastest growing global health emergenciesthey write. An estimated 537 million people had diabetes in 2021, and this number is expected to reach 783 million by 2045.” People with type 1 diabetes need insulin because their pancreas no longer produces it. People with type 2 diabetes may also rely on insulin treatment because the body produces it. becomes insufficient. But how can we ensure sufficient insulin production if cases of diabetes increase? For this team, the answer lies in genetic modifications.”Transgenic animals are considered potential candidates for large-scale production of recombinant proteins and milk, in many cases, represents the most advantageous means of producing them., they continue. Proinsulin is one of these recombinant proteins: it corresponds to the protein precursor of the active form of insulin.
Diabetes: how was the cow genetically modified to produce insulin?
To test this hypothesis, the research team inserted a segment of human DNA encoding proinsulin into the cell nuclei of ten cow embryos. Then, they were implanted in the uteruses of cows in Brazil: from this experiment, a single transgenic calf was born. When the cow reached maturity, the researchers tried to inseminate it, without success. So they decided to stimulate her milk production with hormones, which worked. The result of this experiment surprised them. “Our goal was to make proinsulin, then purify it into insulin, specifies Matt Wheeler, of the department of animal sciences at the University of Illinois, in a communicated. But the cow basically treated it herself.” A few grams of insulin and proinsulin were present in the milk. For Matt Wheeler, if a cow could make 1 gram of insulin per liter, that would be a lot of insulin. “Each gram is equivalent to 28,818 units of insulin, and that’s only one liter; Holsteins can produce 50 liters per dayhe announces. You can do the math.”
Genetically modified cows: what are the risks for the animals?
The researcher and his colleagues plan to continue their experiments. Ultimately, they also want to breed genetically modified bulls, so that they can reproduce with genetically modified cows, or even develop a herd. “We know what we are doing with cows, reassures the scientist. (…) In the old days we used to insert DNA and hope it expressed where you wanted it. We can be much more strategic and focused these days. Using a DNA construct specific to mammary tissue means there is no human insulin circulating in the cow’s blood or other tissues.” With this new technique, they hope to help “hundreds of millions of people all over the world”.