February 16, 2008
IVF Embryo Selection Method Boosts Success 50%

Using a microscope to choose among fertilized embryos for implantation German and Chinese researchers have found a way to boost success rates for in vitro fertilization (IVF).

In future a new method could help some couples who are childless against their will. The microscopic procedure significantly improves the success rate of 'ICSI' (intracytoplasmic sperm injection). This was discovered by scientists at the University of Bonn together with colleagues from China and industrial partners in a study of 124 women. Up to now, the desire to have a child is only fulfilled for every third couple that decides to have ICSI. In a study the artificial insemination method was twice as successful. The scientists have now published their data in the journal 'Reproductive BioMedicine'. (Online version available at http://www.rbmonline.com/Article/3161).

Improvements in artificial insemination technology are going to eventually move into the mainstream when genetic testing starts providing a big advantage for those who choose to start pregnancies with IVF. So you might think an advance like this one only applies to the small minority with fertility problems. But in fact this technique or others like it will eventually get used to start a large fraction of all pregnancies in developed nations.

In cases where they can identify 2 promising ova they can achieve a 50% success rate.

Which of the fertilised ova are finally implanted has usually been left up to chance. But today it is known that not all ova have the same quality. Using a special procedure the Bonn scientists can select the two most suitable candidates. 'For this we observe the ovule integument under a DIC microscope,' Dr. Montag explains. 'There it appears as a luminescent orange-red ring. The brighter this ring is and the more uniformly it shines, the greater the chance that it becomes a child.' The reason for this is that the ovule integument always seems to have a particularly uniform structure if the cell has matured under good conditions.

Normally every third ICSI is successful. But if medics used two 'good ' ova in their experiment, this rate increased to more than 50 per cent. With a 'good' and a 'bad' ovum the success rate was still around 40 per cent, using two 'bad' ones only 20 per cent. 'Mind you, two “good” ova are rare,' Markus Montag emphasises. 'Only with two out of ten cells does the ovule integument have an intense regular orange colour.'

If only 2 out of 10 IVF ova look good by this criteria that makes genetically-based embyro selection harder to do. Ideally one would want to be able to choose among dozens of genetically tested and viable embryos. The more you can choose between the closer you can get to your ideal combination of genes that you'll want to pass along to offspring.

To make selection of offspring by genetic testing viable we still need a few more pieces of biotechnology. First off, we need lots of information about what all the genetic variations mean. That information is now coming in a rapidly increasing torrent. Five years from now we are going to know about hundreds or thousands of genetic variations that contribute to health, size, musculature, coordination, personality, intelligence, endurance, and other characteristics. Second, we need the ability to test for thousands of genetic variations in a cell removed from an embryo. Well, the cost of testing for those genetic variations in cells removed from embryos will continue to fall rapidly. So that's not going to be an obstacle for much longer.

Our third and hard problem: The limited number of good ova. You can't test what you don't have. You can only choose among the viable fertilized embryos that can survive and develop into a baby. To solve this problem we probably need the ability to turn adult cells into eggs. Just turning adult cells into eggs isn't enough. The eggs also need all the regulatory state (called epigenetic state). They need the right genes activated and deactivated.

How long will it take to solve the problem of how to mass produce human eggs with correct epigenetic state from adult cells? Once that problem gets solved the rate of human evolution will accelerate by orders of magnitude.

Share |      Randall Parker, 2008 February 16 12:45 PM  Biotech Reproduction

aa2 said at February 16, 2008 1:02 PM:

One cool thing is seeing researchers from mainland China contributing to research projects. They must have millions of geniuses, who with funding and laboratories and advanced universities could work on the most cutting edge problems.

One interesting thing is the Chinese national budget is growing at above 20% a year in dollar terms. It would be great if they raise the amount they spend on research as the budget grows. Another country that wants to spend on research and has growing means is Russia.

Bob Badour said at February 16, 2008 1:37 PM:

Actually, this advance sounds like the first necessary step to increasing the overall viability rate of IVF ova.

Previously, the only way one could measure whether the ovum was properly handled throughout was to implant it and see how many babies one got. By having the ability to measure how well the ovum was handled before implantation, the door is now open to reducing systemic error a la Deming. If we can measure the error, we can reduce it.

Brock said at February 16, 2008 2:02 PM:

I doubt that "mass produc[tion of] human eggs with correct epigenetic state" will ever be a common means of reproduction. I'm sure we'll figure out how to do it one day, in theory, but it seems to me that (given our current state of technology) we'll have better alternatives by the time we figure that out. I think it will be easier and more efficient to take a cheek swab from each parent, read off their DNA (if this hasn't already been done for health insurance purposes), use a computer to find the optimum combination (with perhaps a few non-parental upgrades thrown in), synthesize the desired DNA directly and insert it into an ova. Each step in that process can already be done in limited ways and needs only to be improved / reduced in cost.

That sounds much easier than creating hundreds (thousands?) of ova randomly and then reading off each of them and sorting for fitness.

Brett Bellmore said at February 17, 2008 6:32 AM:

I suppose the next step, given that they now have a measure of ovum fitness, is to work on a protocol for rehabilitating less than optimal ova. Maybe culturing them in the right medium?

Randall Parker said at February 17, 2008 8:16 AM:

Brett Bellmore,

Some of the unfit ova are that way due to genetic abnormalities. We need to know a lot more what causes unfit ova before we try to make them develop more successfully. Though cell culturing techniques might be contributing to the damage. So there's probably room to improve outcomes.


I think the DNA synthesis approach faces some really tough problems including 3 dimensional folding and setting of epigenetic state. But the DNA synthesis approach would allow a huge step-up in capabilities. We wouldn't be limited to the genetic sequences the two parents have to contribute.

Bob Badour said at February 17, 2008 1:10 PM:


From the excerpt in your article: "The reason for this is that the ovule integument always seems to have a particularly uniform structure if the cell has matured under good conditions." (emphasis added)

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