Σάββατο, 5 Αυγούστου 2017

MAJOR BREAKTHROUGH-FIRST HUMAN EMBRYO GENE EDITING

Human embryo gene editing has been performed for the first time in the United States, a study published today in Nature confirms.
Hong Ma, MD, PhD, with the Oregon Health and Science University's (OHSU's) Center for Embryonic Cell and Gene Therapy, and colleagues used CRISPR-Cas9 technology, a type of molecular scissors, which allows scientists to edit genes with unprecedented precision, to potentially fix defective genes that cause inherited diseases, in this case, a common heart condition that can cause sudden death later in life.
The embryos were allowed to develop only for a few days.
"[T]hese results clearly demonstrate that CRISPR–Cas9 gene targeting in human zygotes is exceptionally efficient," the authors write.
Until now, only three such experiments have been published — all by scientists in China. The first two showed poor results, and the third was more promising but used only six embryos, according to media reports. Dr Ma's team used dozens of embryos.
In November last year in Nature , Carl June, MD, who specializes in immunotherapy at the University of Pennsylvania in Philadelphia, was quoted as saying after the technology was used in China, "I think this is going to trigger 'Sputnik 2.0,' a biomedical duel on progress between China and the United States, which is important since competition usually improves the end product."
Last year, James Clapper, US Director of National Intelligence, in a report to the intelligence community, counted gene editing among threats posed by "weapons of mass destruction and proliferation."
Some critics have bitterly opposed what they say will become attempts to create "designer babies."
However, the National Academies of Science, Engineering, and Medicine said earlier this year in a report that "the technology is advancing very rapidly...making heritable genome editing of early embryos, eggs, sperm, or precursor cells in the foreseeable future 'a realistic possibility that deserves serious consideration.' "
The researchers report that NAS guidelines were part of the policy making for this study: "Human embryo and embryonic stem cell research policies and principles at OHSU were vetted over the course of a decade informed by the NAS guidelines, and subsequently affirmed by new guidelines released in 2015 by the Hinxton Group, the International Society for Stem Cell Research (ISSCR), and 2017 recommendations by the NAS and National Academy of Medicine joint panel on human genome editing."

"A Wake-up Call"

Marcy Darnovsky, PhD, executive director of the Center for Genetics and Society in Berkeley, California, said the research should not have been done and called the findings "a wake-up call."
"Unlike dozens of other countries, we don't have legislation in place that prohibits using edited human embryos to initiate a pregnancy," she said.
Use of edited embryos for that purpose would have to be approved by the US Food and Drug Administration (FDA), and consideration of such an application by the FDA is currently prohibited.
"But there's no codified legal prohibition and those are in place in more than 40 other countries," she said.
The question this new research considers is monumental, Dr Darnovsky said, and could lead to new ways to discriminate. It needs to be addressed by nationwide deliberation, not a single research team, she added. "There's no moral authority for a decision of this magnitude."
"This is not a door that can be opened just a crack," she told Medscape Medical News, adding that she would argue it's not a door that should be opened at all.
She adds that such research is not necessary.
"We already have embryo screening techniques for that exact purpose and they would be effective in the vast majority of cases."

Morally Appropriate

Janet Malek, PhD, associate professor in the Center for Medical Ethics and Health Policy at Baylor College of Medicine in Houston, Texas, takes a different view.
She says there are many situations in which this technology is morally appropriate to use."The cases in which it is most appropriate to use are when it's used to eliminate a serious, debilitating disease," she told Medscape Medical News."There are some risks with it, but also potential benefits and in cases where the diseases are serious, debilitating diseases, the benefits pretty clearly outweigh the risks."
As for embryo screening, Dr Malek said, "that includes creating a lot of embryos and discarding the ones we don't want, whereas this technique, in theory, would allow correction of a genetic disorder within a particular embryo, so the ethical issues of that are actually pretty dramatically different."
"You're picking who exists rather than benefiting somebody."
Drs Darnovsky and Malek report no relevant financial relationships One coauthor is a cofounder and shareholder of ToolGen, Inc, and another is cofounder and shareholder of Mitogenome Therapeutics, Inc, and Health and Science Center "M1" Inc, and have disclosed competing financial interests. The other authors have disclosed no relevant financial relationships.

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