Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Three parents and a baby - Scientists advise caution with regard to artificial insemination method

17.06.2014

The approval of a new treatment method by which three parents will be able to beget a child is being discussed since a few years in Great Britain and will possibly become a reality in two years.

The method is supposed to help in eliminating the mother's genetic defects already in the test tube. The defect lies in so-called mitochondria, the "power houses" of cells. To get rid of defective mitochondria the nucleus of one egg cell has to be transferred to another egg cell bearing intact mitochondria. Scientists at the Vetmeduni Vienna show for the first time that even a few defective mitochondria dragged along in the transfer could cause diseases.


Already a few dysfunctional mitochondria (in yellow on top of the picture) could cause a disease by overgrowing functional ones (in blue). Illustration: Iain Johnston

The results were published in Cell Reports.

Mitochondria are cell organelles located within animal and human cells. They produce energy for the organism, possess their own genetic material - mitochondrial DNA (mtDNA) - and are transmitted exclusively by the mother. Depending on their activity and tasks, different numbers of mitochondria are present in a cell - usually a few hundred to a thousand per body cell.

Inherited mitochondrial disorders or so-called mitochondropathies occur in about one of 10,000 humans throughout the world. Diseases such as diabetes, stroke, cardiac defects, epilepsy, or muscle weakness may originate from mitochondrial defects. Inherited mitochondrial disorders have been incurable so far. Therefore, efforts are now being made to enable women with this disease to bear healthy children by means of nuclear transfer.

Mitochondria multiply at different rates

Jörg Burgstaller, a scientist and member of Gottfried Brem's research group at the Vetmeduni Vienna, has been working for several years on the genetics of mitochondria. It was known before that different types of mitochondria within a cell can proliferate at different rates. However, it was not known whether this is a singular phenomenon or if these cases occur more frequently.

Burgstaller investigated this in four newly bred mouse models which carried different mixtures of mitochondria whose DNA were related to each other to a differing extent. This meant no health problem for the mice since all mtDNAs are were fully functional.

The outcome was: the more distantly two types of mitochondria within an egg cell were related, the more frequently a growth advantage was noted in favor of one of the two types of mitochondria. When two different mtDNAs were equally common in cells of an organ at the time of birth, one type was completely lost after a while. One mitochondria variant had thus achieved a growth advantage compared to the other variant and superseded the latter. This effect was almost non-existent in genetically very similar mitochondria within the cells; the ratio between the two types of mitochondria was not altered in that case.

The effect is of significance in reproduction medicine

Burgstaller's results may have effects on the planned introduction of the so called "Three-Parent Baby" in Great Britain. Experts take the cell nucleus of one human egg cell whose mitochondria have a defect and place it in an egg cell with "healthy" mitochondria. The baby resulting from this procedure has three parents, namely the mother whose cell nucleus is used, the mother whose mitochondria are involved, and the father whose sperm inseminated the egg cell.

However, this method raises the following problem: in every nuclear transfer, a small number of defective mitochondria are transferred into the healthy egg cell. "So far it was believed that this minimal ‘contamination’ is of no consequence for the baby. However, our data show that the effect may have dramatic consequences on the health of the offspring. If the mitochondria of both mothers are genetically very different, it may have the same effects seen in the mouse model," says Burgstaller who developed the theory together with co-author Joanna Poulton, Professor of Mitochondrial Genetics at the John Radcliffe Hospital in Oxford. "One mitochondrial type may be able to assert itself against the other. If the assertive one happens to carry the defective mtDNA, the benefit of the therapy would be jeopardized."

The solution to the "Three-Parent Baby"-problem

Burgstaller and his colleagues suggest the following solution to the problem: the mtDNA of both mothers, i.e. the donor of the nucleus and the donor of the mitochondria, should be analyzed in advance and aligned to each other. So called “machting haplotypes” could prevent the dangerous effect. In the future the effect may even be utilized in a targeted manner to suppress defective mtDNA.

The work was conducted in cooperation with BIAT (Biomodels Austria) and the technology platform Vetcore at Vetmeduni Vienna, Joanna Poulton from John Radcliffe Hospital in Oxford, Jaroslav Piálek from the Czech Academy of Sciences, and Iain Johnston and Nick Jones from the Imperial College (London).

The article „mtDNA Segregation in Heteroplasmic Tissues Is Common In Vivo and Modulated by Haplotype Differences and Developmental Stage”, by Joerg Patrick Burgstaller, Iain G. Johnston, Nick S. Jones, Jana Albrechtová, Thomas Kolbe, Claus Vogl, Andreas Futschik, Corina Mayrhofer, Dieter Klein, Sonja Sabitzer, Mirjam Blattner, Christian Gülly, Joanna Poulton, Thomas Rülicke, Jaroslav Piálek, Ralf Steinborn and Gottfried Brem was published in the journal Cell Reports. DOI: 10.1016/j.celrep.2014.05.020 http://www.sciencedirect.com/science/article/pii/S2211124714003957

About the University of Veterinary Medicine, Vienna
The University of Veterinary Medicine, Vienna in Austria is one of the leading academic and research institutions in the field of Veterinary Sciences in Europe. About 1,200 employees and 2,300 students work on the campus in the north of Vienna which also houses five university clinics and various research sites. Outside of Vienna the university operates Teaching and Research Farms. http://www.vetmeduni.ac.at

Scientific Contact:
Dr. Joerg Burgstaller
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-5639
M +43 664 3767262
joerg.burgstaller@vetmeduni.ac.at

Released by:
Susanna Kautschitsch
Science Communication / Public Relations
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-1153
susanna.kautschitsch@vetmeduni.ac.at

Weitere Informationen:

http://www.vetmeduni.ac.at/en/infoservice/presseinformation/press-releases-2014/...

Dr. Susanna Kautschitsch | idw - Informationsdienst Wissenschaft

Further reports about: Medicine Poulton Veterinary artificial mitochondria mitochondrial mtDNA

More articles from Life Sciences:

nachricht How molecules teeter in a laser field
18.01.2019 | Forschungsverbund Berlin

nachricht Discovery of enhanced bone growth could lead to new treatments for osteoporosis
18.01.2019 | University of California - Los Angeles

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Ten-year anniversary of the Neumayer Station III

The scientific and political community alike stress the importance of German Antarctic research

Joint Press Release from the BMBF and AWI

The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...

Im Focus: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

Im Focus: Nanocellulose for novel implants: Ears from the 3D-printer

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

Im Focus: Elucidating the Atomic Mechanism of Superlubricity

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

Additive manufacturing reflects fundamental metallurgical principles to create materials

18.01.2019 | Materials Sciences

How molecules teeter in a laser field

18.01.2019 | Life Sciences

The cytoskeleton of neurons has been found to be involved in Alzheimer's disease

18.01.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>