{"id":38584,"date":"2017-08-03T12:03:19","date_gmt":"2017-08-03T12:03:19","guid":{"rendered":"https:\/\/www.biphoo.com\/bipnews\/?p=38584"},"modified":"2017-08-03T12:03:19","modified_gmt":"2017-08-03T12:03:19","slug":"first-human-embryo-editing-experiment-in-u-s-repairs-gene-for-heart-condition","status":"publish","type":"post","link":"https:\/\/www.biphoo.com\/bipnews\/health\/first-human-embryo-editing-experiment-in-u-s-repairs-gene-for-heart-condition.html","title":{"rendered":"First human embryo editing experiment in U.S. repairs gene for heart condition"},"content":{"rendered":"

First human embryo editing experiment in U.S. repairs gene for heart condition<\/span><\/strong><\/span><\/h2>\n

First human embryo editing experiment in U.S. repairs gene for heart condition:- In a first, researchers safely repaired a disease-causing gene in human embryos, targeting a heart defect best known for killing young athletes \u2014 a big step toward one day preventing a list of inherited diseases.<\/span><\/p>\n

A research team led by Oregon Health & Science University reported Wednesday that embryos can help fix themselves if scientists jump-start the process early enough.<\/span><\/p>\n

It\u2019s laboratory research only, nowhere near ready to be tried in a pregnancy.<\/span><\/p>\n

But it suggests that scientists might alter DNA in a way that protects not just one baby from a disease that runs in the family but his or her offspring as well. And that raises ethical questions.<\/span><\/p>\n

\u201cI for one believe, and this paper supports the view, that ultimately gene editing of human embryos can be made safe. Then the question truly becomes, if we can do it, should we do it?\u201d said Dr. George Daley, a stem cell scientist and dean of Harvard Medical School.<\/span><\/p>\n

He wasn\u2019t involved in the new research and praised it as \u201cquite remarkable.\u201d<\/span><\/p>\n

\u201cThis is definitely a leap forward,\u201d agreed developmental geneticist Robin Lovell-Badge of Britain\u2019s Francis Crick Institute.<\/span><\/p>\n

The new research comes less than six months after the National Academies of Science, Engineering and Medicine recommended that scientists limit their trials of what is often called human germ-line editing to diseases that could not be treated with \u201creasonable alternatives\u201d \u2014 at least for now.<\/span><\/p>\n

Genetics and ethics experts not involved in the work say it\u2019s a critical first step \u2014 but just one step \u2014 toward eventually testing the process in pregnancy, something currently prohibited by U.S. policy.<\/span><\/p>\n

\u201cThis is very elegant lab work,\u201d but it\u2019s moving so fast that society needs to catch up and debate how far it should go, said Johns Hopkins University bioethicist Jeffrey Kahn.<\/span><\/p>\n

Today, couples seeking to avoid passing on a bad gene sometimes have embryos created in fertility clinics so they can discard those that inherit the disease and attempt pregnancy only with healthy ones, if there are any.<\/span><\/p>\n

Gene editing in theory could rescue diseased embryos. But germ-line changes \u2014 altering sperm, eggs or embryos \u2014 are controversial because they would be permanent, passed down to future generations.<\/span><\/p>\n

Critics worry about attempts at \u201cdesigner babies\u201d instead of just preventing disease. And a few previous attempts at learning to edit embryos, in China, didn\u2019t work well and, more important, raised safety concerns.<\/span><\/p>\n

In a series of laboratory experiments reported in the journal Nature, the Oregon researchers tried a different approach.<\/span><\/p>\n

They targeted a gene mutation that causes a heart-weakening disease, hypertrophic cardiomyopathy, that affects about 1 in 500 people. Inheriting just one copy of the bad gene can cause it.<\/span><\/p>\n

The team programmed a gene-editing tool, named CRISPR-Cas9, that acts like a pair of molecular scissors to find that mutation \u2014 a missing piece of genetic material.<\/span><\/p>\n

Then came the test. Researchers injected sperm from a patient with the heart condition along with those molecular scissors into healthy donated eggs at the same time. The scissors cut the defective DNA in the sperm.<\/span><\/p>\n

Normally, cells will repair a CRISPR-induced cut in DNA by essentially gluing the ends back together. Or scientists can try delivering the missing DNA in a repair package, like a computer\u2019s cut-and-paste program.<\/span><\/p>\n

Instead, the newly forming embryos made their own perfect fix without that outside help, reported Oregon Health & Science University senior researcher Shoukhrat Mitalipov.<\/span><\/p>\n

We all inherit two copies of each gene, one from dad and one from mom \u2014 and those embryos just copied the healthy one from the donated egg.<\/span><\/p>\n

\u201cThe embryos are really looking for the blueprint,\u201d said Mitalipov, who directs OHSU\u2019s Center for Embryonic Cell and Gene Therapy. \u201cWe\u2019re finding embryos will repair themselves if you have another healthy copy.\u201d<\/span><\/p>\n

It worked 72 percent of the time, in 42 out of 58 embryos. Normally a sick parent has a 50-50 chance of passing on the mutation.<\/span><\/p>\n

Previous embryo-editing attempts in China found that not every cell was repaired, a safety concern called mosaicism. Beginning the process before fertilization avoided that problem: Until now, \u201ceverybody was injecting too late,\u201d Mitalipov said.<\/span><\/p>\n

Nor did intense testing uncover any \u201coff-target\u201d errors, cuts to DNA in the wrong places, reported the team, which also included researchers from the Salk Institute for Biological Studies in California and South Korea\u2019s Institute for Basic Science.<\/span><\/p>\n

The embryos weren\u2019t allowed to develop beyond eight cells, a standard for laboratory research. The experiments were privately funded; U.S. tax dollars aren\u2019t allowed for embryo research.<\/span><\/p>\n

Lots more research is needed to tell if it\u2019s really safe, Lovell-Badge said.<\/span><\/p>\n

\u201cWhat we do not want is for rogue clinicians to start offering treatments\u201d that are unproven, as has happened with some other experimental technologies, he stressed.<\/span><\/p>\n

Among key questions: Would the technique work if mom, not dad, harbored the mutation? Is repair even possible if both parents pass on a bad gene?<\/span><\/p>\n

Mitalipov is \u201cpushing a frontier,\u201d but it\u2019s responsible basic research that\u2019s critical for understanding embryos and disease inheritance, noted University of Pittsburgh professor Kyle Orwig.<\/span><\/p>\n

Source:-\u00a0http:\/\/www.omaha.com\/livewellnebraska\/health\/first-human-embryo-editing-experiment-in-u-s-repairs-gene\/article_e9a418c4-77b6-11e7-a43a-9b2c2f1b0de6.html<\/span><\/p>\n

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