By: Sylvina Raver, Ph.D.
Biotechnology and Bioethics
Scientists edit the genome in human embryos for the first time
Scientists now have access to technologies that allow them to edit DNA sequences in human tissue with relative ease. As has been discussed in detail previously, the safety and ethical considerations of permanently altering the human genome are considerable. Genetic modifications, however well intentioned, may be unsafe and result in unintended consequences in the embryo. And because these alterations can be passed on to subsequent generations of people, the far-reaching effects are substantial as well. In light of the many concerns raised by these technological advances, the scientific community has been nearly unanimous in calling for a temporary moratorium on genetic engineering in human embryos until the technical, safety, and bioethical concerns can be more fully understood. However, not all scientists are adhering to this temporary ban. This week a team of researchers at Sun Yat-sen University in Guangzhou, China published a report in the online journal Protein & Cell describing how they were able to successfully modify the genetic code in human embryos. The scientists, led by Dr. Junjiu Huang, performed experiments in non-viable human embryos using the CRISPR-Cas9 technology to modify a gene called HBB, mutations of which can lead to the fatal blood disorder beta-thalassemia. The scientists found that the rate of successful editing was quite low; only 28 of the 86 very early embryos studied demonstrated successful repair of the HBB gene. In addition to the relatively low efficacy of this technique, the paper also reported that embryos contained multiple unintended changes to their DNA. The authors state that their results highlight the need to improve the fidelity and efficacy of the CRISPR-Cas9 platform if it is to be applied in clinical settings in the future. Despite these qualifications, responses to the report by the international scientific community have been swift and mostly critical. Many scientists and watchdog groups argue that these experiments underscore the need for a moratorium on germline gene modification. However, other prominent voices in the bioethical and stem cell communities praise the value of basic research aimed at improving genetic engineering methods. A wave of similar research reports may be on the horizon as multiple Chinese research teams are rumored to be conducting ongoing experiments to edit the genome of human embryos. (David Cyranoski & Sara Reardon, Nature; Rob Stein, NPR; Jocelyn Kaiser & Dennis Normile, ScienceInsider)
Contraceptive implants could decrease the rate of unplanned teenage pregnancies in the US
The rate of unplanned pregnancies in the United States is nearly 50%, and since 2001 the US made no substantial progress toward reduce this number. In teenage women between the ages of 15-19, the rate of unintended pregnancy is nearly seven times higher than in countries like Switzerland or the Netherlands. Many of these pregnancies could be averted through more widespread use of highly effective forms of birth control, including hormonal implants (miniature plastic rods inserted under the skin) or intrauterine devices (IUDs). The failure rate for these forms of contraception is only about 0.2%, which is remarkably lower than those for more commonly used methods like the pill (9%) or condoms (18%). Furthermore, because implants and IUDs are inserted and then remain stable for multiple years, they remove the need for women to remember to take a daily pill, or to rely on her partner to use a condom. Long-term contraception essentially changes the default, so that instead of actively preventing pregnancy, women can instead consciously decide when to conceive. Yet despite these clear advantages, only 7% of American teenage women use implants or IUDs, compared to nearly 40% of women in China. A primary reason for the limited use may be lack of information. A recent survey by the National Campaign to Prevent Teen and Unplanned Pregnancy found that nearly 77% of American women knew “little to nothing” about implantable birth control. Misconceptions about the safety and efficacy of these devices are also prevalent, possibly due to a lingering collective memory of a defective IUD that caused infections in some women and was removed from the market in the 1970’s. However, a lack of adequate information concerning implants does not lie solely with patients. Despite guidelines that require medical providers to recommend implants and IUDs as the “first-line” method of birth control for teenagers, many practitioners are not trained to insert these devices or worry that they are not suitable for teenagers. Medical providers, including pediatricians, who many teenagers first approach for birth control, must be reminded of the benefits of recommending IUDs and implants, and must be trained to properly insert and remove these devices. Increased promotion of IUDs and implants by public health agencies is also warranted. States that have increased the prevalence of these devices have seen both their birth rates and abortion rates fall dramatically among teens, particularly those in lower socioeconomic brackets. (The Economist)
Major earthquake devastates Nepal, may herald more Himalayan tremors
A 7.8 magnitude earthquake struck late in the morning of Saturday April 25, 2015 and has devastated a large portion of central Nepal, including the capital city of Kathmandu and the mountaineering destination of Mount Everest. At least 3,800 people are dead in what may prove to be one of the most deadly natural disasters to strike the Himalayas in years. Sadly, an earthquake of this magnitude was not unexpected, as the tectonic plates underneath Nepal have been close to the breaking point for centuries. The same geological forces that cause the Himalayan Mountains to reach such towering heights cause this region to be one of the most seismically active in the world. While seismic events are not unexpected in Nepal, the socioeconomic situations of many Nepalese citizens, combined with a rapid rate of urbanization, contribute to the devastation wrought by the April 25th quake. Much of the older infrastructure in villages and cities like Kathmandu has not been upgraded to withstand earthquakes. And as the country becomes more urbanized, new construction that lacks structural reinforcement often occurs hastily in dense and impoverished neighborhoods. Earthquake recovery, rather than prevention, will likely dominate Nepal for the foreseeable future. While the April 25 quake released much of the strain accumulating within the faults in the region, many experts feel that this earthquake was not sufficient to relieve all of the building pressure, and predict more than 30 aftershocks greater than magnitude 5 in the coming weeks. (Matt Schiavenza, The Atlantic; Alexandra Witze, Nature; Priyanka Pulla, ScienceInsider)
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