Scientists Create a Genetically Modified Cow That Produces Human Insulin in Milk
Researchers from Brazil, including biotechnologists at the University of Northern Paraná and the University of São Paulo, with collaboration from colleagues in the United States, reported the creation of a transgenic cow capable of producing human insulin proteins in its milk. The discovery appeared in the scientific journal Biotechnical Journal, marking a notable step in the field of therapeutic protein production.
The team introduced a precise segment of human DNA that encodes proinsulin into the cell nuclei of ten cow embryos. These embryos were subsequently implanted into the uteri of typical dairy cows in hopes of developing healthy offspring carrying the genetic modification.
Only one of the ten embryos resulted in a successful pregnancy and the natural birth of a viable transgenic calf. As the animal matured, researchers explored methods to fertilize the genetically modified individual through artificial means, in vitro techniques, and even traditional approaches. While none of these attempts yielded a successful pregnancy, the researchers interpreted this as a limitation of embryo creation methods rather than a consequence of the genetic modification itself.
With the calf reaching adulthood, scientists applied hormonal protocols to stimulate milk production, aiming to harvest milk for analysis of the inserted human proteins. The resulting milk contained substances that could be processed to form human insulin, though the overall yield was lower than that observed during pregnancy. The data indicated the presence of components in the milk that could be converted to functional insulin suitable for further study.
In their assessment, the authors estimated that a herd of about 100 transgenic cows could generate enough insulin to meet the needs of a country the size of the United States, highlighting the potential scale of production. Prior researchers have explored various biological strategies to influence blood sugar control, including the use of dairy-origin substances for therapeutic purposes. The work thus contributes to ongoing discussions about how livestock could serve as a biomanufacturing platform for essential medicines, while also underscoring the challenges and ethical considerations involved in translating these findings to widespread use.
Experts stress that this line of inquiry requires careful examination of safety, regulatory frameworks, and long-term effects on animal welfare, with ongoing research needed to validate the viability of large-scale insulin production via milk. The study, though promising, remains a foundational demonstration rather than a directly implementable industry model at this stage, and further work will determine whether such approaches can become practical, economical, and ethically acceptable in real-world healthcare settings. [Citation: Biotechnical Journal, author group from Brazilian institutions with U.S. collaboration]