Latest news with #mitochondria
Yahoo
2 days ago
- Health
- Yahoo
Breakthrough study uncovers biological trigger that forces the brain to sleep
We spend nearly a third of our lives sleeping, yet the biological trigger behind sleep has remained elusive. Despite decades of research, scientists have struggled to identify a concrete, physical reason why the brain demands rest. A new study from the University of Oxford might have changed that. Researchers have found that the pressure to sleep may come from deep inside our brain cells, from the tiny power plants known as mitochondria. These structures, responsible for converting oxygen into energy, appear to sound an internal alarm when pushed into overdrive. The team, led by Professor Gero Miesenböck and Dr. Raffaele Sarnataro, discovered that a build-up of electrical stress inside mitochondria in specific brain cells acts as a signal to trigger sleep. The research, carried out in fruit flies, showed that when mitochondria become overcharged, they leak electrons. 'When they do, they generate reactive molecules that damage cells,' said Dr. Sarnataro. This electron leak produces what are known as reactive oxygen species, byproducts that, in high quantities, can damage cellular structures. The brain appears to respond to this imbalance by initiating sleep, giving the cells a chance to reset before damage spreads further. The findings open a new chapter in how scientists think about energy metabolism's role in brain health. Switch in the brain The researchers found that specialized neurons function like circuit breakers. These cells measure the electron leak and trip the sleep response when the stress crosses a threshold. By manipulating the energy flow in these neurons, either by increasing or decreasing electron transfer, the scientists could directly control how long the flies slept. They even bypassed the system's normal inputs by replacing electrons with energy from light using microbial proteins. The result remained the same: more energy, more leak, more sleep. 'We set out to understand what sleep is for, and why we feel the need to sleep at all,' said Professor Miesenböck. 'Our findings show that the answer may lie in the very process that fuels our bodies: aerobic metabolism.' He explained that when the mitochondria in certain sleep-regulating neurons are overloaded with energy, they begin leaking electrons. When this leak becomes too great, the neurons trigger sleep to prevent damage from escalating. Ties to aging and fatigue The findings may help explain why metabolism and sleep are so closely linked. Small animals that consume more oxygen per gram of body weight tend to sleep more and live shorter lives. Meanwhile, people with mitochondrial disorders often experience extreme fatigue even without physical exertion. This new mechanism offers a potential explanation. 'This research answers one of biology's big mysteries,' said Dr. Sarnataro. 'Why do we need sleep? The answer appears to be written into the very way our cells convert oxygen into energy.' These insights could reshape not just sleep science, but also how doctors understand chronic fatigue, neurological disorders, and the aging process itself. The study is published in the journal Nature. Solve the daily Crossword
CBC
4 days ago
- Health
- CBC
8 babies born with experimental 3-parent IVF technique
Eight healthy babies were born in Britain with the help of an experimental technique that uses DNA from three people to help mothers avoid passing devastating rare diseases to their children, researchers report. Most DNA is found in the nucleus of our cells, and it's that genetic material — some inherited from mom, some from dad — that makes us who we are. But there's also some DNA outside of the cell's nucleus, in structures called mitochondria. Dangerous mutations there can cause a range of diseases in children that can lead to muscle weakness, seizures, developmental delays, major organ failure and death. Testing during the in vitro fertilization process can usually identify whether these mutations are present. But in rare cases, it's not clear. Researchers have been developing a technique that tries to avoid the problem by using the healthy mitochondria from a donor egg. They reported in 2023 that the first babies had been born using this method, where scientists take genetic material from the mother's egg or embryo, which is then transferred into a donor egg or embryo that has healthy mitochondria but the rest of its key DNA removed. The latest research"marks an important milestone," said Dr. Zev Williams, who directs the Columbia University Fertility Center and was not involved in the work. "Expanding the range of reproductive options … will empower more couples to pursue safe and healthy pregnancies." Using this method means the embryo has DNA from three people — from the mother's egg, the father's sperm and the donor's mitochondria — and it required a 2016 U.K. law change to approve it. It is also allowed in Australia but not in many other countries, including the U.S. and Canada. Experts at Britain's Newcastle University and Monash University in Australia reported in the New England Journal of Medicine Wednesday that they performed the new technique in fertilized embryos from 22 patients, which resulted in eight babies that appear to be free of mitochondrial diseases. One woman is still pregnant. One of the eight babies born had slightly higher than expected levels of abnormal mitochondria, said Robin Lovell-Badge, a stem cell and developmental genetics scientist at the Francis Crick Institute who was not involved in the research. He said it was still not considered a high enough level to cause disease, but should be monitored as the baby develops. Dr. Andy Greenfield, a reproductive health expert at the University of Oxford, called the work "a triumph of scientific innovation," and said the method of exchanging mitochondria would only be used for a small number of women for whom other ways of avoiding passing on genetic diseases, like testing embryos at an early stage, was not effective. Lovell-Badge said the amount of DNA from the donor is insignificant, noting that any resulting child would have no traits from the woman who donated the healthy mitochondria. The genetic material from the donated egg makes up less than 1 per cent of the baby born after this technique. Safety and ethical questions remain "If you had a bone marrow transplant from a donor … you will have much more DNA from another person," he said. In the U.K., every couple seeking a baby born through donated mitochondria must be approved by the country's fertility regulator. As of this month, 35 patients have been authorized to undergo the technique. Critics have previously raised concerns, warning that it's impossible to know the impact these sorts of novel techniques might have on future generations. "Currently, pronuclear transfer is not permitted for clinical use in the U.S., largely due to regulatory restrictions on techniques that result in heritable changes to the embryo," Williams, of Columbia, said in an email. "Whether that will change remains uncertain and will depend on evolving scientific, ethical, and policy discussions." For about a decade, Congress in the U.S. has included provisions in annual funding bills banning the Food and Drug Administration from accepting applications for clinical research involving techniques, "in which a human embryo is intentionally created or modified to include a heritable genetic modification." But in countries where the technique is allowed, advocates say it could provide a promising alternative for some families. Liz Curtis, whose daughter Lily died of a mitochondrial disease in 2006, now works with other families affected by them. She said it was devastating to be told there was no treatment for her eight-month-old baby and that death was inevitable. She said the diagnosis "turned our world upside down, and yet nobody could tell us very much about it, what it was or how it was going to affect Lily." Curtis later founded the Lily Foundation in her daughter's name to raise awareness and support research into the disease, including the latest work done at Newcastle University.
Yahoo
5 days ago
- Health
- Yahoo
8 babies spared from potentially deadly inherited diseases through new 'mitochondrial donation' trial
When you buy through links on our articles, Future and its syndication partners may earn a commission. Mitochondria, the powerhouses of cells, contain their own special DNA that gets passed from mother to child — but that DNA can sometimes carry mutations, causing diseases for which there are currently no cures. Now, in a new clinical trial, eight babies who had a high risk of inheriting such diseases from their moms appear to have been spared, thanks to an emerging technique called "mitochondrial donation." The approach used in the trial has been in development for many years and is only just making its way into human patients. Early attempts at mitochondrial donation were first described in mouse experiments published in the 1980s, said study co-author Mary Herbert, a professor of reproductive biology at Monash University in Melbourne. After that came studies in human embryos that were fertilized through in vitro fertilization (IVF) but unfit for use, so they were instead donated for research. Then, world-first legislation passed in the United Kingdom in 2015 enabled research with good-quality human embryos, which was necessary to show the technique could actually result in a viable pregnancy. Since then, scientists have refined the approach for transferring healthy mitochondria into embryos, troubleshooting the many problems that arose along the way. "There were hurdles at every stage," said Herbert, who also holds appointments at Newcastle University and the Newcastle Fertility Centre in the U.K. Now, the trial results, described in two reports published Wednesday (July 16) in The New England Journal of Medicine, may offer a solution to parents who otherwise have a very high likelihood of passing these diseases to their kids. "It's just such a burden that goes down through the generations of women in these families," Herbert said. "It really is gratifying to be able to do something, to offer some kind of way out." Related: 8-year-old with rare, fatal disease shows dramatic improvement on experimental treatment "This has brought joy and relief to the parents" Inherited mitochondrial diseases, estimated to affect about 1 in 5,000 births, can cause a wide range of symptoms, including seizures, muscle weakness, fatigue, vision loss, heart disease, developmental delay and learning disabilities. These symptoms can range from mild and manageable to severe and life-threatening, with more serious presentations typically arising shortly after birth. Although it's known that the mutations behind these diseases are inherited from mom, their transfer from parent to offspring is still somewhat unpredictable. That's because, in a given egg, the "mutational load" can vary — some eggs carry mitochondrial DNA with few to no harmful mutations, while others carry mitochondria with only mutated DNA. If affected parents conceive without the help of reproductive technologies, "they might have a child who's perfectly healthy or a child who dies in the first few days of life, essentially," Herbert said. Moms-to-be who carry a mix of high-load and low-load eggs have the option to handpick eggs with low loads using preimplantation genetic testing (PGT), a technique paired with IVF. However, "the ones who are not suitable for PGT are people who have very high mutation loads in all their eggs — sometimes 100% mutation loads," Herbert explained. These patients, who aren't necessarily super sick themselves but would likely pass on concerning mutations, are the ones who could benefit from mitochondrial donation. In the trial, researchers directly compared the PGT approach to mitochondrial donation. All the participants carried disease-causing mitochondrial DNA mutations, and they all underwent intracytoplasmic sperm injection (ICSI), a form of IVF in which a single sperm cell is injected straight into an egg to trigger fertilization. Patients with low enough mutational loads in some of their eggs were offered PGT, while those whose mutational loads were too high were offered mitochondrial donation. The donation itself could be done a few different ways, but in the trial, the researchers used "pronuclear transfer," in which an egg is fertilized before having its nucleus removed and placed in a different, donated egg cell. The donated egg had been screened for known mitochondrial mutations and also had its own nucleus removed. As such, the resulting embryo carries the nuclear DNA from the egg and sperm used for fertilization, as well as mitochondrial DNA from the donor egg. Ultimately, 16 of 39 patients given PGT became pregnant, resulting in 18 babies born (including some twins). By comparison, 8 of 22 patients who received mitochondrial donation got pregnant, resulting in the birth of eight babies, so far, as there's one pregnancy still ongoing. Both techniques resulted in a similar proportion of pregnancies out of the total people treated. "This process has brought joy and relief to the parents of these children, who thought they were never going to be able to have children without the risk of mitochondrial disease," said study co-author Dr. Bobby McFarland, a professor of pediatric mitochondrial medicine and honorary consultant pediatric neurologist at Newcastle University. "To be part of the team effort to make that happen has been very special indeed," he told Live Science in an email. Related: In a 1st, child treated for rare, often-fatal disorder while still in the womb Refining the technique even further All the babies conceived through mitochondrial donation were born healthy and are meeting their developmental milestones, the team reported. "We are now proud parents to a healthy baby — a true mitochondrial replacement success," one mother to a baby boy said in a statement. "This breakthrough has lifted the heavy cloud of fear that once loomed over us." The children's health will continue to be monitored closely going forward. "We have cast a wide net for clinical health data reporting on these children and also included a detailed developmental assessment at 18 months," McFarland said. "We are in the process of amending the study to look for more subtle developmental problems at 5 years." Notably, the pronuclear transfer procedure doesn't guarantee that every last scrap of mitochondrial DNA in the baby will be from the donor egg. That's because, in the process of moving the nucleus from one egg to another, some small amount of mom's mitochondrial DNA can be carried over with the nucleus, Herbert explained. In the eight babies born so far, some had undetectable levels of maternal mitochondrial DNA in their blood cells while others have a detectable amount, but the concentration is below that which would be expected to cause disease. However, the team will need to watch to see if that mutation-carrying DNA becomes more plentiful over time, Herbert said. "We have to view these technologies as risk reduction; we cannot guarantee prevention," she said, emphasizing that parents are informed of this limitation prior to the procedure and counseled about all their options. Looking forward, the scientists hope to refine the technique to reduce the risk of that carry-over as much as possible, while also making the process more efficient and easy to reproduce. Although the two groups of parents in the trial differed from one another, especially in terms of their mutational loads, it was good to compare the groups directly, Robin Lovell‑Badge, a principal group leader at the Francis Crick Institute in the U.K., wrote in an accompanying commentary in The New England Journal of Medicine. RELATED STORIES —Scientists just discovered a single molecule that may treat rare, devastating mitochondrial diseases —1st-of-its-kind database reveals how DNA mutations 'destabilize' proteins, triggering genetic disease —1 gene may explain 30 mysterious medical conditions "Having the group that underwent PGT as the comparison group strengthens the conclusion that pronuclear transfer is a valid method to reduce the risk of mtDNA [mitochondrial DNA] disease," he wrote. "The articles, which were hotly anticipated, show a (cautiously) good outcome and are well worth the wait," he added. Research into mitochondrial donation will continue in the U.K., as well as in Australia, which passed similar regulations to the U.K. in 2022 to enable such studies, Herbert noted. McFarland added of the current trial that "this is still a relatively small number of babies so we do need to follow up more and for longer." Meanwhile, in the U.S., the Food and Drug Administration does not currently allow clinical research into these types of "mitochondrial replacement techniques" in humans, in part due to long-standing regulations passed by Congress. This article is for informational purposes only and is not meant to offer medical advice.
Washington Post
5 days ago
- Health
- Washington Post
Healthy babies born in Britain after scientists used DNA from three people to avoid genetic disease
LONDON — Eight healthy babies were born in Britain with the help of an experimental technique that uses DNA from three people to help mothers avoid passing devastating rare diseases to their children, researchers reported Wednesday. Most DNA is found in the nucleus of our cells, and it's that genetic material — some inherited from mom, some from dad — that makes us who we are. But there's also some DNA outside of the cell's nucleus, in structures called mitochondria. Dangerous mutations there can cause a range of diseases in children that can lead to muscle weakness, seizures, developmental delays, major organ failure and death.
Yahoo
5 days ago
- Health
- Yahoo
Healthy babies born in Britain after scientists used DNA from three people to avoid genetic disease
LONDON (AP) — Eight healthy babies were born in Britain with the help of an experimental technique that uses DNA from three people to help mothers avoid passing devastating rare diseases to their children, researchers reported Wednesday. Most DNA is found in the nucleus of our cells, and it's that genetic material — some inherited from mom, some from dad — that makes us who we are. But there's also some DNA outside of the cell's nucleus, in structures called mitochondria. Dangerous mutations there can cause a range of diseases in children that can lead to muscle weakness, seizures, developmental delays, major organ failure and death. Testing during the in vitro fertilization process can usually identify whether these mutations are present. But in rare cases, it's not clear. Researchers have been developing a technique that tries to avoid the problem by using the healthy mitochondria from a donor egg. They reported in 2023 that the first babies had been born using this method, where scientists take genetic material from the mother's egg or embryo, which is then transferred into a donor egg or embryo that has healthy mitochondria but the rest of its key DNA removed. The latest research 'marks an important milestone,' said Dr. Zev Williams, who directs the Columbia University Fertility Center and was not involved in the work. 'Expanding the range of reproductive options … will empower more couples to pursue safe and healthy pregnancies.' Using this method means the embryo has DNA from three people — from the mother's egg, the father's sperm and the donor's mitochondria — and it required a 2016 U.K. law change to approve it. It is also allowed in Australia but not in many other countries, including the U.S. Experts at Britain's Newcastle University and Monash University in Australia reported in the New England Journal of Medicine Wednesday that they performed the new technique in fertilized embryos from 22 patients, which resulted in eight babies that appear to be free of mitochondrial diseases. One woman is still pregnant. One of the eight babies born had slightly higher than expected levels of abnormal mitochondria, said Robin Lovell-Badge, a stem cell and developmental genetics scientist at the Francis Crick Institute who was not involved in the research. He said it was still not considered a high enough level to cause disease, but should be monitored as the baby develops. Dr. Andy Greenfield, a reproductive health expert at the University of Oxford, called the work 'a triumph of scientific innovation,' and said the method of exchanging mitochondria would only be used for a small number of women for whom other ways of avoiding passing on genetic diseases, like testing embryos at an early stage, was not effective. Lovell-Badge said the amount of DNA from the donor is insignificant, noting that any resulting child would have no traits from the woman who donated the healthy mitochondria. The genetic material from the donated egg makes up less than 1% of the baby born after this technique. 'If you had a bone marrow transplant from a donor … you will have much more DNA from another person,' he said. In the U.K., every couple seeking a baby born through donated mitochondria must be approved by the country's fertility regulator. As of this month, 35 patients have been authorized to undergo the technique. Critics have previously raised concerns, warning that it's impossible to know the impact these sorts of novel techniques might have on future generations. 'Currently, pronuclear transfer is not permitted for clinical use in the U.S., largely due to regulatory restrictions on techniques that result in heritable changes to the embryo," Williams, of Columbia, said in an email. 'Whether that will change remains uncertain and will depend on evolving scientific, ethical, and policy discussions." For about a decade, Congress has included provisions in annual funding bills banning the Food and Drug Administration from accepting applications for clinical research involving techniques, 'in which a human embryo is intentionally created or modified to include a heritable genetic modification.' But in countries where the technique is allowed, advocates say it could provide a promising alternative for some families. Liz Curtis, whose daughter Lily died of a mitochondrial disease in 2006, now works with other families affected by them. She said it was devastating to be told there was no treatment for her eight-month-old baby and that death was inevitable. She said the diagnosis 'turned our world upside down, and yet nobody could tell us very much about it, what it was or how it was going to affect Lily.' Curtis later founded the Lily Foundation in her daughter's name to raise awareness and support research into the disease, including the latest work done at Newcastle University. 'It's super exciting for families that don't have much hope in their lives,' Curtis said. ___ Ungar reported from Erie, Pennsylvania. ——- The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content. Maria Cheng And Laura Ungar, The Associated Press
