Scientists were able to engineer a cow that can produce necessary human insulin proteins in its milk. Specialists believe that a herd of such transgenic cattle could help solve global insulin supply issues.
Insulin
Insulin was first found in 1921. For several years, people with diabetes received insulin treatments, with the insulin taken from the pancreas of pigs and cattle.
In 1978, human insulin first saw production. This was sourced from the proteins of genetically modified E. coli bacteria, which is the main medical insulin source today. Similar processes have also been conducted to make use of yeast rather than bacteria.
Read also: Diabetes Breakthrough: Researchers Restore Insulin Production Using Drug Available in the Market
Transgenic Cow Can Produce Human Insulin Proteins
Though the idea of turning cows into a supply of human insulin is not a novel one, this study marks the first time that human insulin production has been successfully done in a genetically engineered bovine. Efforts were noted in the "Human proinsulin production in the milk of transgenic cattle" study.
As part of the study, the researchers inserted a human DNA segment that codes proinsulin, which is the protein that gets converted into insulin, into 10 cow embryos' cell nuclei. The embryos were inserted into normal cow wombs.
One of the embryos successfully developed into a pregnancy. A transgenic calf was then born naturally.
Upon reaching maturity, the researchers made various attempts to get the transgenic cow pregnant. They tried out in vitro fertilization, artificial insemination, and even old-fashioned approaches. However, none of these ended up successful. The scientists note that this could be more related to the creation of the embryo rather than its genetically modified nature.
They eventually induced lactation in the cow through hormonal induction. They made use of an undisclosed approach that is attributed to Pietro Baruselli, an animal reproduction technologist from the University of Sao Paulo.
Though the lactation of the cow was not as much compared to typical pregnancy, the little milk it produced in one month was examined for finding certain proteins, such as mass spectrometry and western blotting.
The blotting showed two bands that had similar molecular masses with insulin and proinsulin. These were not present in non-transgenic cow milk.
Mass spectrometry showed that C-peptide was present. In the process of insulin creation, this peptide is removed from proinsulin. This suggests that the milk of the cow converted human proinsulin and turned it into insulin.
Matt Wheeler, the study's lead author and an animal scientist from the University of Illinois Urbana-Champaign, explains that their aim was to produce proinsulin, convert it into insulin, and move forward from them. However, the cow was basically able to process it on her own.
A typical insulin unit is roughly 0.0347 milligrams. Hence, if each cow could produce a gram of insulin per one liter of milk, this would be equivalent to 28,818 insulin units.
Wheeler explains that a high-health-status and specialized facility would be necessary for such cattle. The animal scientist adds that this is nothing extraordinary, considering the advancements and establishments of the dairy industry.
If such a cattle herd was viable, it may out-compete current productions of insulin, which mainly depend on genetically modified bacteria and yeast. However, based on the first case, it may take a long way for such a herd to be viable.
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