In the making: growth hormone milker

Aime Jõgi
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Photo: Margus Ansu / Postimees

Cloned calf born this summer may bless Estonia with Skype-type success.

There was a question which Tartu university professors Ülle Jaakma and Sulev Kõks struggled to answer, at clone calf presentation yesterday: to which grand event, in recent world history, would they compare their achievement? 

«Don’t know...» clumsily mumbled Ms Jaakma, Vice Prorector at Estonian University of Life Sciences.

«Like the flight by Gagarin, you mean?» came an attempt to crack a joke by Mr Kõks, professor of physiological genomics at University of Tartu.

«Skype, perhaps?» offered a journalist in the auditorium.

Mr Kõks delved deep within. «Yeah, in a sense we might indeed draw some calf-Skype parallels, as onto this achievement something may be built,» said he.

The read-and-white transgenic calf talked about, meanwhile, was taking its rest on a heap of straw, at a nearby pen of life sciences’ university. As the reporters – smocks and hats on – came over to take a curious look, it purposefully got to its feet and came over, staring into various cameras, then proceeding to lick the pen bars and a hand stuck in belonging to a carer, senior research fellow Jevgeni Kurõkin.

Birthday pangs

The transgenic calf born by cooperation between the two universities came into this world on June 22nd. And was thus christened Juuni (the Estonian for June).

The animal was born early, by Caesarean section, promptly taken to another room to be attended with the care given to a newborn child in intensive care.

Junior veterinarian Maria Kivastik recalls how she and her two colleagues took turns with the calf, the whole summer long, watching after the creature 24/7.

«The calf weighed 47 kg at birth; had an oxygen tube stuck in her nose, and a cannula in a vein. Plus bottle-feeding with milk,» said Ms Kivastik. «That was an intense day. But when it started to breathe and showed signs of vitality, all rejoiced.»

The intensity of the day being one reason why the calf, born two and a half months ago, was only revealed to the public last week – very quietly. Now the animal is growing fast, full of life and weighing 120 kg. Eating grass and drinking from a bucket.

Behind the birth, in June, lay over five months of purposeful labour. Reading out the list of the team, Mr Kõks took several minutes.

The very first cloned calf came to be, in Tartu, last fall; however, death took it on week two (by navel inflammation). The professor has earlier said that five years ago, cloning seemed a thing so elegant and easy, so he thought: two years – and it’s done!

To put it very briefly: making a cloned calf goes as follows. You take a ripe ovum, remove its nucleus and replace it with a nucleus of a skin cell from the cloned animal. Into the latter, prior to that, has been installed a gene construct with a smart chain of command, which, when the clone cow births its first calf, tells its mammary glands what kind of milk is to be produced. 

The ovum with changed nucleus is stuck into an incubator, to grow. It is attempted to make many such ovums. Not always, however, will the clone-embryos develop to the stage needed to be transplanted. After seven days, the most vital embryos will be planted into cows. In nine months, these will give birth to cloned calves.

In the work, lots of factors must come in line, starting with the creation of the gene construct; the labs and the mice used to test the constructs; to finding the «foster mother» and then giving birth.

Juuni the Calf’s genome now includes an artificially created human growth hormone gene; hopefully, the calf will be producing milk containing growth hormone. The hormone can then be extracted from the milk and used in pharmaceutical industry, significantly enhancing the quality and lowering the costs of producing medicines.

The Tartu scientists confessed they were not too sure how much growth hormone Juuni’s milk would contain.

«That’ll be seen in two years after Juuni has had calves and we get the initial milk,» said Prof Jaakma. «Should there prove to be a couple of grams per litre, we would have reason to be happy. Considering that a cow will milk 40 litres a day, that would mean 80 grams; as a medicine, that’s a huge quantity.»

The short-term plan of the scientists is to try and raise up a transgenic cattle of 10-15 cows. Mr Kõks believes that the peculiar cows-to-be will not come about with as much toil as Juuni. For, now, Juuni’s own cells can be used to do the cloning.

So far, life sciences university has had over ten animals impregnated with transgenic cloned embryos. As revealed by history, half of such pregnancies tend to fail.

«This is a weakness in cloning technology the whole world is battling, to no avail,» said Ms Jaakma. According to the professor, there may still be two pregnant cows of that sort. «Two months ago there were, at least,» said she.

Medicine-milking cattle

Still, Mr Kõks and Ms Jaakma assure us that that are much wiser now than five years ago; their hands being much more steady at creating transgenic beasts.

By the latter, they do not merely mean cows milking growth hormone; there would be such as produce hormones stimulating erythropoietin, insulin, or follicles, for instance.

Asked how much money has been spent to come to the achievement now reported, Mr Kõks and Ms Jaakma said that it has cost roughly 25 million Estonian kroons; helped by Enterprise Estonia and many other partners.

Why clone a calf?

To the question regarding the amount of transgenic clone calves in the world, Ms Jaakma answered it was hard to tell, exactly – there being no such register.

«Scientific institutions tend to announce their calves; commercial enterprises may keep mum – that’s part of their business,» said she.

Ms Jaakma said that as far as we know, there is one more calf like Juuni on the planet – in Argentina.

«In New Zealand, the scientists are banking on the hope that, in the future, people would not shy back from consuming milk by cloned cows; thus, they have increased casein content in the milk of their cows – that serves to produce more cheese,» related Ms Jaakma.

The professor also says there has been an attempt to reduce, in milk, the content of such proteins as cause milk allergies in humans.

In China, scientists have produced cows with medicines in their milk affecting the immune system.

Prof Kõks adds that there are, actually, multiple examples of medicines gotten from transgenic cloned animals.

«A problem in the pharmaceutical industry is production of biological medicines, which is complicated and expensive due to technological nuances,» said he. «Transgenic cloning helps make these medicines cheaper.»

Mr Kõks proceeds to describe two medicines marketed in the world, already, produced from transgenic goat milk. One is called ATryn – an antithrombin. The other being Ruconest, helpful to patients with angioedema.

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