Today, people with diabetes can lead normal lives beyond logical control of their diet, thanks to insulin administration. This hormone began to be extracted in the 1920s. pancreas of pigs and cows, but since it was not human insulin, it sometimes caused allergies. Moreover, to obtain it on a large scale, many animals had to be sacrificed. Even if those who worked in the meat industry took advantage of this, sometimes it was not enough. In the 70s, this problem was solved through the production of human insulin. use of bacteria like little hormonal factories. But now a group of Brazilian scientists wanted to go further and develop cows that can produce insulin in their milk.
This is not something new. Previous studies have already been conducted on mice. Experimental protocol for development transgenic cows or goats. But until now this has not been implemented. For the first time a cow has been produced whose milk can be extract insulin. The process still has a lot of polishing to do, starting with the fact that the cow couldn’t get pregnant. Milk production was only possible through hormonal stimulation, and obviously this was not ideal.
In addition, the amount of insulin in the milk was low. But this is the first giant step towards making insulin that will be much more effective and cost-effective in the long run.
Factories for the production of human insulin for diabetics
Bacteria divide at a high rate. Without a doubt, they reproduce much faster than any animal. Therefore, its replication system is a very good tool to obtain large amounts of insulin.
This has also been done with yeast, but most often it is bacteria, especially coli. Broadly speaking, the process involves introducing into the body a genetic sequence with instructions for synthesizing human insulin. DNA of bacteria. Thus, every time it divides, it makes new copies and produces the corresponding hormone.
What if getting insulin was as easy as milking a cow?
This is something that has been studied for a long time. Several studies have been conducted on mice genetically modified so that their milk contains insulin when they breed. It is created by inserting a gene into your DNA that makes insulin, but with a slight twist. Mice, like cows, are more complex animals than simple bacteria. all your cells They will have the same DNA, but each cell will use the instructions that suit it best. For example, in humans the gene for insulin synthesis is present in all cells, but it is used only in the pancreas. For example, we don’t need eyes to produce the hormone. This is what is known as gene expression. All genes are present in all cells, but not all of them are expressed.
Since this requires that insulin be produced in mammary glandin mouse studies, the gene was introduced next to goat casein promoter. A promoter is a sequence that specifies where a gene should begin to be transcribed. That is, it indicates where the process begins so that these instructions lead to protein synthesis. Casein is a protein found in milk. Therefore, its promoter specifies that it should only be used on the mammary glands. When injected near this promoter, insulin will be synthesized in the mammary glands and released into the milk.
New step: insulin in cow’s milk
It’s true that milking a mouse is possible, but bringing it to an industrial scale is not easy. So once it was discovered that it was something viable in mice, scientists carried out a similar process, but in cows.
There are two options for the synthesis of human insulin in bacteria. You can get two chains which make up the hormone separately and then attach it chemically or use the sequence of proisulin, the protein from which insulin is derived. Both in mice and now in cows the sequence proinsulin.
Using genetic engineering, the gene was introduced into the nucleus 10 cow embryos. Again, appropriate promoters were used to ensure that the gene was expressed only in mammary cells. These embryos were transferred into the uterus of adult cows, but only one was able to bear offspring. full-term pregnancy. The born calf was completely healthy. When she reached adulthood, an attempt was made to inseminate her to see if there would be proinsulin in her milk when she had children, but she was unable to become pregnant. However, this doesn’t worry scientists too much as they believe their infertility has more to do with the process they used to produce the embryos than their genetic modifications. In any case, they managed to get her to produce milk by hormonal stimulation. It did not produce as much as if it were giving birth, but it served to search for insulin.
Surprise in milk
When analyzing milk samples from this genetically modified cow, the scientists saw something that caught their attention. First, in comparison with the milk of non-transgenic cows, the presence of a molecule whose mass corresponded to proinsulin was observed. But, in addition, using another technique, the presence of a peptide was discovered that is released when proinsulin is converted into insulin. Therefore, the transformation will not have to be carried out a posteriori as planned. happened spontaneously.
According to the calculations of these scientists, if technologies are improved, it will be possible to achieve one gram of insulin for every liter of milk. This would mean that with just a hundred cows, they would have insulin for all of Brazil. There is still time for this to become a reality; but without a doubt they are on the right track.
Source: Hiper Textual