Tag Archives: IVF

IVF pioneer Sir Robert Edwards dies aged 87

We are saddened to learn that IVF pioneer Professor Sir Bob Edwards has died at the age of 87, following a long illness. The University of Cambridge announced his death earlier today, noting that through his work Professor Edwards had improved the lives of millions of people around the world. Speaking about his former colleague, Professor Martin Johnson, Emeritus Professor of Reproductive Science at the University of Cambridge noted that Professor Bob was not only a scientific pioneer, but recognized the importance of explaining your research to the public:

Bob Edwards was a remarkable man who changed the lives of so many people. He was not only a visionary in his science but also in his communication to the wider public about matters scientific in which he was a great pioneer.”

Professor Sir Robert Edwards, Nobel Laureate and IVF pioneer

Professor Sir Robert Edwards, Nobel Laureate and IVF pioneer

With his colleague Dr Patrick Steptoe, Professor Edwards performed the first human in-vitro fertilization procedure, which resulted the birth of Louise Joy Brown in 1978.  35 years later more than 4 million children have been born through IVF around the world, and in 2010 Professor Edwards was awarded the Nobel Prize in Physiology or Medicine “for the development of in vitro fertilization”. Unfortunately, as the University of Cambridge statement notes, Professor Edwards was already in poor health when the prize was announced.

The developments for which Edwards and Steptoe were responsible attracted much publicity, some of it, not least from the Vatican, highly critical.

Formal recognition therefore came late, but when it did come, it was decisive, with the award of the Nobel Prize for Physiology or Medicine in 2010 ‘for the development of in vitro fertilization.”

For Professor Edwards the Nobel Prize came late, but for his colleague Dr. Steptoe, who had predeceased him in 1988, it came too late. Dr. Steptoe was not alone in this. When Professor Edwards was awarded the Nobel Prize in 2010 we published a blog post welcoming the award and discussing the key contribution of animal research to the development of IVF, noteing that Dr. Min Chueh Chang – whose studies in rodents and rabbits led directly to the techniques used by Professor Edwards and Dr. Steptoe – was also denied a share in the 2010 Nobel prize as he had died in 1991. Knowing this adds to the poignancy of a moment when we remember the achievements of some of the greatest scientists of the 20th century.

Today our thoughts are with Professor Edwards’ family, friends and colleagues, but we also remember those other scientists and surgeons who worked with him to usher in a revolution in medical care that has brought happiness to millions of people across the globe.

Speaking of Research

From Macaques to Humans: UK regulator gives cautious thumbs up to advanced IVF techniques to prevent mitochondrial disease

Yesterday the UK’s Human Fertilisation and Embryology Authority (HFEA) advised the government that there is no evidence the two advanced forms of IVF developed to prevent mitochondrial diseases are unsafe, recommending that research using human embryos should continue, with close monitoring of the  health of children born through these two techniques, which are known as maternal spindle transfer and pronuclear transfer. At the same time the HFEA announced that a public consultation undertake last year had found broad support for the techniques.

The UK parliament will need to make the final decision on whether these techniques – somewhat misleadingly dubbed “three person embryos” – should be allowed, and it’s important to note that even if they give their approval the HFEA stressed in its assessment that further studies of human embryos in the lab will need to take place over the next 3 to 5 years before they can move into the clinic. These further studies will help to minimize any risks associated with the procedures, though Professor Robin Lovell Badge, a member of the HFEA panel that undertook a thorough scientific review of the science underpinning the techniques, did stress in a statement to the BBC that the ultimate test of the techniques would only cone then they were tried in the clinic.

Safety is absolutely not a black and white issue. In reproductive medicine in particular it is not possible to be absolutely certain about the consequences of any new treatment until children are born.

“Someone at some point is going to have to take the brave decision to go ahead with it.”

This announcement demonstrates that 35 years after the birth of the first IVF baby, the UK still leads the way in pioneering reproductive medicine. The UK did not get here alone though, as scientists in other countries – particularly the USA – have played a vital role in the development of these techniques.

In particular just a few months ago we discussed how Professor Shoukhrat Mitalipov of the Oregon National Primate Research Center  had developed the technique of spindle–chromosomal complex transfer – a.k.a. maternal spindle transfer, and one of the two techniques that the HFEA assessed  – through studies of Rhesus macaque monkeys. These studies included one where the health of four monkeys created using these techniques was followed closely for three years, with no ill effects observed.

Mitochondrial Gene Therapy. Source Mitalipov Lab/OSHU

Mitochondrial Gene Therapy. Source Mitalipov Lab/OSHU

The development of offspring born through the technique of pronuclear transfer, which was originally developed through research in mice, has not yet been studied in primates. Professor Douglass Turnbull of Newcastle University , who has demonstrated the technique is viable in human embryos in vitro, has cited the Rhesus macaque studies undertaken by Professor Mitalipov as evidence for the safety of the approach.

It is good to see the positive but cautious approach being adopted by the HFEA  as these techniques developed through a synergy of in vivo research on mice and monkeys and in vitro research on human embryonic cells in vitro move closer to becoming a clinical reality for the many parents who are waiting for them.

Speaking of Research

New gene therapy for mitochondrial diseases a step closer thanks to ONPRC

Mitochondria are fascinating. These tiny organelles that reside within almost all of the cells in our bodies (mature red blood cells being an exception) generate the supply of a molecule called adenosine triphosphate (ATP) which is the principle source of energy that cells, and ultimately ourselves, need to survive. They also have an intriguing evolutionary history, being descended from bacteria that over one and a half billion years ago formed a symbiotic relationship with primitive eukaryotic cells that are the ancestors of today’s plants and animals. A legacy of this ancestry is that animal mitochondria contain a tiny genome that encodes 37 genes that are crucial to the mitochondria’s function, and separate from the main genome which is found in the nucleus of the cell and contains just over 20,000 coding genes. Unlike nuclear genes, half of which are inherited from our mother and half from our father, mitochondrial genes are almost always inherited from the mother only, which means that if a mother has a mitochondrial genome mutation it will always be passed on to her children.  However, since a human egg cell contains many mitochondria, and only some of them may be defective, there is usually a threshold level of defective mitochondria which must be reached before the defects cause disease in children, and the severity of disease can be very variable. Nevertheless inherited mitochondrial disorders affect as many as 4,000 children born in the USA every year, and for almost all of them treatment options are limited.

One way in which the transmission of mitochondrial diseases can be prevented is by screening embryos during IVF, and earlier this year we reported on how a team at the Oregon National Primate Research Centre (ONPRC) led by Dr. Shoukhrat Mitalipov discovered through studies performed on Rhesus macaques how to improve the efficiency of this screening. However in cases where screening does not identify eggs that are free from mitochondrial genetic defects other ways of preventing transmission of the disorders are being examined, and one of these is the possibility of replacing the damaged mitochondria with healthy mitochondria from a donor.

Yesterday in a publication in Nature (1), Dr. Mitalipov’s team at ONPRC announced another major advance made possible through research on Rhesus monkeys, the first demonstration that it is possible to replace the faulty mitochondria of a human egg cell before fertilization and create healthy looking human embryos, from which embryonic stem cells could be derived that were identical to controls created through normal IVF.

Mitochondrial Gene Therapy. Source Mitalipov Lab/OSHU

Briefly, the procedure involved the removal of the nuclear genetic material from the egg of a patient whose mitochondrial DNA contains mutations, and its transplantation into an egg containing normal mitochondrial DNA from which the nuclear genetic material has been removed.  More detailed descriptions and discussion of the process used in this therapy and the team’s results can be found on the Oregon Health and Science University website, reports on the BBC and LA Times, and in Nature News, it’s clearly been a study that has caught the imagination of a lot of people!  It’s worth noting that a child born after fertilization with the partner’s sperm would be free of risk from maternal mtDNA mutations as well as being the biological child of the patients, since the mitochondrial genome accounts for only 37 of over 20,000 coding genes in the body it is inaccurate to refer to these as 3 parent embryos.

The news reports make it very clear that research on monkeys was crucial to this advance, indeed the potential of the technique used – which they term spindle–chromosomal complex transfer – was first demonstrated when they were able to produce 3 healthy monkey infants in 2009 (2).  They started by examining the distribution of Rhesus monkey mitochondria during the process of meiosis – the type of cell division through which gametes (sperm and egg cells) are produced – using confocal laser scanning microscopy, and observed that at a particular late stage in the process termed the  metaphase II stage the mitochondria were distributed relatively uniformly throughout the cytoplasm,  except immediately around the chromosomes and the spindle apparatus (a protein structure segregates chromosomes between daughter cells during cell division), which were devoid of mitochondria.  This suggested that it might be possible to isolate the spindle–chromosomal complex at this stage and transfer it to an egg cell from which the egg had been removed without transferring any mitochondria at the same time.

A significant challenge was how to avoid damaging the spindle-nuclear complex during this operation, but the team had recently developed new techniques to transfer the nuclei of adult skin cells from monkeys into egg cells and successfully derive embryonic stem cells from the resulting clones.  By modifying these techniques they were able to reconstructed eggs that were capable of being fertilized normally, undergoing embryo development and producing healthy offspring. Genetic analysis confirmed that nuclear DNA in the three infant macaques originated from the spindle donors whereas mitochondrial DNA came from the cytoplast donors. This set the stage for the work announced yesterday.

In addition to reporting the production of human embryos through spindle–chromosomal complex transfer (ST) this week’s Nature paper (1) also reported the outcome of follow-up examination from birth to 3 years of four monkeys born through ST – the 3 reported in 2009 and one born subsequent to that publication – and found that they were developing normally and were in good health.

Because egg cells only remain viable for a short period of time after they are harvested from a donor, it is considered crucial that ST can be performed successfully using frozen egg cells for this technique to be clinically viable, so the team also examined if it was possible to do this using thawed Rhesus macaque cells. They were successful; the experiment resulted in the birth of a healthy monkey. More surprisingly they also found to their surprise that while the spindle–chromosomal complex could withstand prior cryopreservation the technique failed when the egg into which the spindle-chromosal complex is transferred had been frozen – indicating that most of the damage to the frozen egg is to its cytoplasm, rather than to the nucleus as had previously been thought, a discovery that may have wider implications for the future improvement of human egg cryopreservation and IVF techniques.

Impressive as this study is it is by no means the end of the road, this technique needs further refinement and optimization before anyone should attempt to use it in the clinic, but it does provide both scientists and ethicists with very valuable information.  This is particularly true in the UK, where the Human Fertilisation and Embryology Authority is reviewing this technique and another that is being developed by Professor Mary Herbert at the University of Newcastle. Speaking to the BBC yesterday, Peter Braude, Professor of Obstetrics and Gynaecology at King’s College London, said:

It is exactly the sort of science that the HFEA expert committee recommended needed doing, and demonstrates further the feasibility of this technique.”

We at Speaking of Research congratulate Dr. Mitalipov and his team at ONPRC on their groundbreaking work.

Paul Browne

1)      Masahito Tachibana, Paula Amato, Michelle Sparman, JoyWoodward, Dario Melguizo Sanchis, Hong Ma, Nuria Marti Gutierrez, Rebecca Tippner-Hedges, Eunju Kang, Hyo-Sang Lee, Cathy Ramsey, Keith Masterson, David Battaglia, David Lee, Diana Wu, Jeffrey Jensen, Phillip Patton, Sumita Gokhale, Richard Stouffer& Shoukhrat Mitalipov “Towards germline gene therapy of inherited mitochondrial diseases” Nature Published online 24 Oct 2012, doi:10.1038/nature11647

2)      Masahito Tachibana, Michelle Sparman, Hathaitip Sritanaudomchai, Hong Ma, Lisa Clepper, Joy Woodward, Ying Li, Cathy Ramsey, Olena Kolotushkina & Shoukhrat Mitalipov “Mitochondrial gene replacement in primate offspring and embryonic stem cells” Nature 461, 367-372 (2009) doi:10.1038/nature08368

OHSU Rhesus macaque embryo research to improve Preimplantation Genetic Diagnosis

Preimplantation Genetic Diagnosis is used by parents to screen embryos produced through in-vitro fertilization (IVF) in order to ensure that the baby will be free of specific genetic diseases.  New research from Oregon Health and Science University on the inheritance of the mitochondrial genome indicates that screening for genetic mutations that are located in the genome of the mitochondria – which is outside the nucleus of the cell where the much larger chromosomal genome id found, and is inherited only from the mother – can be made more accurate by carrying out the screening procedure slightly later than is now the practice.

Dr. Shoukhrat Mitalipov, who led this research project, explains what the project involved and its implications

A press release from OHSU highlights the importance of the Rhesus macaque to this discovery about the inheritance of mitochondial genomes:

“This latest breakthrough, which was conducted in rhesus macaque monkeys because of their similarity to humans, demonstrates the specific stage of early embryonic development when genetic mutations are passed from mother to fetus. This stage, referred to by scientists as “the bottleneck,” occurs when an early embryo called blastocyst, transitions into a fetus.

To conduct the research, Mitalipov and colleagues needed to design a way to mark and track specific mitochondrial genes as they transitioned from egg, through fertilization, to embryo and then to fetus. This was accomplished by combining two separate mitochondrial genomes into one egg cell. More specifically, one-half of an egg cell from a species of Indian-continent rhesus macaque monkey was merged with one-half of an egg cell from a Chinese-continent monkey. Because these animal species have distinct mitochondrial gene sequences (like breeding two distinct species of dogs), their genetics could be tracked closely.

The microscopic manipulation of splitting and uniting two halved egg cells takes specialized skills and expertise, which the Mitalipov lab has developed over a period of several years.

By studying the development of these joined and then fertilized eggs, scientists were surprised to see that eggs transitioned from containing a 50/50 split of genetics to a fetus that contained a nearly 100 percent either Indian or Chinese-based genome.

 We discovered that during early development, each individual cell in the eight-cell embryo would contain varying percentages of the Indian and Chinese rhesus genes. Some would be a 50/50 split. But others would be 90/10 and so on,” explained Mitalipov. “When these percentages were combined as a whole embryo, the average genetic split between the two species was about equal as initially created. However, later during the transition from a blastocyst to fetus, the genetics would swing one way or another. The resulting offspring would have always a genome that is predominantly Chinese or Indian. Our study tells us precisely when this mitochondrial gene switch occurs and how this can lead to disease.”

This finding raises significant questions about validity of currently methods for genetic diagnosis in early embryos, when a woman is known to carry a mitochondrial gene mutation may pass a disease to her children.

The current pre-implantation genetic diagnosis method is to examine genetic disease risk is by taking one cell from an early eight-cell embryo, and then looking for mutations in that one particular cell. This is done to predict if the remaining embryo is mutation-free,” explained Mitalipov.

The problem with this approach is that you may choose a cell that may not have mutations. But that does not mean the remaining cells in an embryo are mutation-free. Our research suggests that such approach could be flawed because diagnosis takes place prior to the stage when an offspring’s mitochondrial genetics is truly established.”

With this new information and with additional data gathered through further research, Mitalipov and colleagues believe that new methods for genetic diagnosis for mitochondrial disease should be located. The research also demonstrates that the Mitalipov lab’s previously developed method for preventing the passing of mitochondrial mutations from mother to child is highly successful.”

It’s an important discovery, one with important implications for preimplantation genetic diagnosis, and we congratulate Dr. Mitalipov and his colleagues at OHSU on their success!

Lee, H., Ma, H., Juanes, R., Tachibana, M., Sparman, M., Woodward, J., Ramsey, C., Xu, J., Kang, E., Amato, P., Mair, G., Steinborn, R., & Mitalipov, S. (2012). Rapid Mitochondrial DNA Segregation in Primate Preimplantation Embryos Precedes Somatic and Germline Bottleneck Cell Reports DOI: 10.1016/j.celrep.2012.03.011

Bob Edwards wins 2010 Nobel Prize for developing IVF: Thank the mice, rabbits, hamsters…

Professor Robert G. Edwards of the University of Cambridge has long been recognized as one of the pioneers of reproductive medicine. His most famous accomplishment, along with surgeon Patrick Steptoe*, came in 1978 with the birth of Louise Joy Brown, the first baby born through in-vitro fertilization.  This achievement has now been recognized by the Nobel Assembly who awarded him the Nobel Prize in Physiology or Medicine 2010 for “the development of in vitro fertilization”.

As Dario discussed in an article for this blog a few months ago the development of IVF by Bob Edwards depended on basic and applied research undertaken in rabbits and hamsters by pioneers including Gregory Pincus and Min Chueh Chang, who identified the essential conditions required for IVF.

In advanced information accompanying today’s announcement the Nobel Assembly notes the importance of this research in laying the foundations for the development of human IVF by Bob Edwards and Patrick Steptoe, and also discusses how Bob Edwards’ own extensive research on the reproductive biology of mice – and animal research he and his colleagues conducted in a variety of species while working on IVF – aided progress. In particular the Nobel Assembly highlights how his experience with mice in enabled Bob Edwards to solve a critical problem that was preventing successful IVF, by developing a way to harvest human egg cells at the optimal stage of their maturation prior to in vitro fertilization.

Professor Robert Edwards, Nobel Laureate and IVF pioneer

Without the decades of careful animal research undertaken by Bob Edwards, Gregory Pincus, Min Chueh Chang, and scores of their colleagues it is unlikely that IVF would ever have become a reality.

We heartily congratulate Professor Edwards on his Nobel Prize, an award that recognizes his outstanding contribution to a medical advance that has brought joy to hundreds of thousands of families around the world.

* Sadly Patrick Steptoe died in 1988 and therefore could not share the Nobel Prize with Robert Edwards.

Paul Browne

Animal Research Benefits Mom and Baby Alike

The contributions of animal research to human health are many.

In response to blanket statement that animal research “does not work” I wanted to provide three examples of how animal research has directly benefited the health of women and their babies: in-vitro fertilization, oral contraceptives and neonatal intensive care.

Do you or any of your friends conceived with help of in-vitro fertilization?  Do you know how the method was developed?

It turns out that rabbits played a central role in the development of in-vitro fertilization.   As far abck as 1891 Walter Heape in England reported the first known case of embryo transplantation from one rabbit species to another, thereby showing that it was possible to transfer the embryos to a gestational carrier without adverse effects.  In 1934 Dr. Gregory Pincus at Harvard achieved in-vitro fertilization in rabbits for the first time, and he made very detailed studies in animals of the effects of hormones on ovulation and early embryonic development.  Being ahead of his time brought him much negative reputation and was described by the media a modern “Dr. Frankestein” (in fact, he was denied tenure due to these experiments.)   In 1958 Dr. Min Chueh Chang demonstrated conclusively that IVF was possible by implanting black rabbit embryos conceived in the lab into a white rabbit.  His studies in rabbits, rats, mice and hamsters during the 1950’s, 60’s, and 70’s, identified key conditions for IVF to be successful, such as the need for sperm capacitation.  These findings paved the way for the development of in-vitro fertilization in humans by Dr. Robert Edwards and Dr. Patrick Steptoe, which allows families to have a children overcoming many obstacles to pregnancy, both in cases of female and male infertility.  Approximately 60,000 infants are born with the help of IVF in the US every year…   Thank the rabbits.

Have you ever asked yourself where oral contraceptives come from?

The “pill” was first introduced in the 60s based on synthetic hormones that mimic the way progesterone works to prevent ovulation.  In 1919 Dr Ludwig Haberlandt and colleagues first demonstrated that transplantation of ovaries of pregnant rabbits into fertile female rabbits suppressed their ovulation.   Shortly before his death Haberlandt was able to prevent pregnancy in mice through the oral administration of an extract from the ovaries. It later was discovered that this was caused by the hormone progesteroneMargaret Sanger, the famous American birth control activist,  asked Dr. Gregory Pincus (the same one that developed IFV) to think of new methods of contraception and, building on these results, he showed that repeated injections of progesterone indeed could stop ovulation in rabbits.   This key finding, along with the development of a synthetic version of progesterone, led the first clinical trials of “the pill” in Puerto Rico.   Identifying effective synthetic progesterones was not an easy task, Dr. Pincus and Dr. Chang screened over 200 candidates before identifying three that prevented ovulation in laboratory animals.  The subsequent clinical trials of one of these synthetic progesterones were successful and Enovid was approved by the FDA in 1957.   Thank the rabbits again…

Dr Gregory Pincus and Dr Min Chueh Chang, pictured alongside artificial insemination pioneer Sir John Hammond. Courtesy of Mrs. F. Hammond.

Have you any of your friends had a premature baby in the intensive care unit?   Do you know why survival rates are now much higher than in the past?

The rate of premature birth has increased by 36% since the 80s (1).  Most babies born before 37 weeks of pregnancy are premature and are at risk of many complications.  In the USA alone, about 12.8% of babies are born prematurely and will spend their first few days of their lives in the neonatal intensive care unit.  Among babies born before the 34th week, 23,000 a year of them suffer from respiratory distress syndrome (RDS).  Such babies lack a protein in their lungs (called surfactants) that keep the air sacs in the lungs from collapsing.

Surfactants were discovered and their chemical composition analyzed using dogs in biomedical research and through research on rabbits and lambs surfactant therapy, initially using surfactant from cows and later synthetic surfactant, was developed.  The fruits of this research were translated into the treatments using surfactants in the 90s, which reduced the death of babies from RDS by about 50% (2).  In other words, slightly more than 10,000 babies are saved every year just in the US alone due to surfactant-replacement therapy.

That’s more than one baby per hour just in the US… Saved.  Thanks to animal research.

And this work goes on, for example in recent posts Paul has discussed the use of brain cooling and xenon gas to protect babies who have suffered oxygen starvation during birth from brain damage.

So when animal rights activists and the medical wing of their movement state that animal research “does not work”, what they really mean is that it does not work… for them.

Yet, they cannot deny these facts with books full of half-truths and out-of-context citations.

Anyone can walk into the nearest neonatal ICU and face the babies and their parents.  Face the facts.

Dario Ringach

References:

(1) Martin, J.A., et al. Births: Final Data for 2006. National Vital Statistics Reports, volume 57, number 7, January 7, 2008.

(2) Engle, W.A., and the Committee on Fetus and Newborn. Surfactant-Replacement Therapy for Respiratory Distress in the Preterm and Term Neonate. Pediatrics, volume 121, number 2, February 2008, pages 419-428