Tag: embryonic development

Bioethics News

Viable human embryos CRISPR genetically edited in the USA. Technique and ethical controversies

Numerous complications could go unnoticed in this study

On 26th July, the journal MIT Technology Review  announced that the CRISPR technique (see HERE) had been applied in human embryos for the first time in the United States, in a study led by embryologist Shoukhrat Mitalipov of Oregon Health and Science University.

Gene editing has previously been performed on human embryos on at least three occasions in China. Accordingly, two articles from 2015 (see HERE) and 2016, respectively, reported the application of CRISPR on non-viable human embryos (see HERE) . Subsequently, in 2017, another paper reported the application of CRISPR on human embryos, this time viable (See HERE ). In all cases, the results revealed that there are still serious safety and efficacy obstacles before the method can even be considered for use in medical applications. Consequently, the editing was completely successful in only a very small number of embryos, and moreover, there were undesirable effects like mosaicism (when only some of the embryonic cells incorporate the desired change) and off-target mutations.

The findings of the new study were published on 2nd August in Nature. Most relevant, though, is not the fact that viable human embryos have been edited for the first time in the US, but that the problems of mosaicism and off-target mutations found in previous studies appear to have been largely overcome.

The technique

The experiment consisted of correcting a mutation in the MYBPC3 gene, which causes a heart disease. The mutation was found in the DNA of the sperm used to fertilize the eggs.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

Bioethics News

The amazing finding of senescent cells in embryos. Until now, these cells had been found only in aging tissue

The discovery raises the possibility that the start and end of life are intimately connected

The process by which cells cease multiplying is known as senescence. In 1961, biologists Hayflick and Moorehead cryoconserved human fetal cells and found that these divide around 50 times and then simply stop doing so, as occurs in the human body (see recent article, AGING CELLS ARE KEY TO FINDING FOUNTAIN OF YOUTH)

In fact, senescent cells are involved in many of the signs of aging: wrinkled skin, cataracts, and arthritic joints, which are produced by the effect of an increase in these cells. On the contrary, it has been found that by decreasing senescent cells in mice, signs of rejuvenation can be detected in these animals.

Considering that in all research, senescent cells have been found only in old or damaged tissues, the last place one would expect to find them would be at the very beginning of life, in the embryo. Now, however, three scientific teams have reported that they have observed the same phenomenon at this point.

Senescent cells in embryos

For the first time, senescent cells have been found in embryos, and scientists have presented proof that senescence is crucial for their proper development.

This discovery raises the possibility that the start and end of life are intimately connected. In order for life to have a good start, senescent cells are needed, i.e. youth needs a little bit of old age.

Scott Lowe, an expert in senescence at Memorial Sloan-Kettering Cancer Center, who did not participate in the research, has lauded the studies, which point to the unexpected role of old age, and predicted that it would provoke a spirited debate between developmental biologists, who study how embryos are formed.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

Bioethics News

The biological status of the early human embryo. When does human life begins?

“Those who argue that that embryo can be destroyed with impunity will have to prove that this newly created life is not human. And no-one, to the best of our knowledge, has yet been able to do so.”

Introduction

In order to determine the nature of the human embryo, we need to know its biological, anthropological, philosophical, and even its legal reality. In our opinion, however, the anthropological, philosophical and legal reality of the embryo — the basis of its human rights — must be built upon its biological reality (see also HERE).

Consequently, one of the most widely debated topics in the field of bioethics is to determine when human life begins, and particularly to define the biological status of the human embryo, particularly the early embryo, i.e. from impregnation of the egg by the sperm until its implantation in the maternal endometrium.

Irrespective of this, though, this need to define when human life begins is also due to the fact that during the early stages of human life — approximately during its first 14 days — this young embryo is subject to extensive and diverse threats that, in many cases, lead to its destruction (see HERE).

These threats affect embryos created naturally, mainly through the use of drugs or technical procedures used in the control of human fertility that act via an anti-implantation mechanism, especially intrauterine devices (as DIU); this is also the case of drugs used in emergency contraception, such as levonorgestrel or ulipristal-based drugs (see HERE), because both act via an anti-implantation mechanism in 50% of cases.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

Bioethics News

The biological status of the early human embryo. When does human life begins?

“Those who argue that that embryo can be destroyed with impunity will have to prove that this newly created life is not human. And no-one, to the best of our knowledge, has yet been able to do so.”

Introduction

In order to determine the nature of the human embryo, we need to know its biological, anthropological, philosophical, and even its legal reality. In our opinion, however, the anthropological, philosophical and legal reality of the embryo — the basis of its human rights — must be built upon its biological reality (see also HERE).

Consequently, one of the most widely debated topics in the field of bioethics is to determine when human life begins, and particularly to define the biological status of the human embryo, particularly the early embryo, i.e. from impregnation of the egg by the sperm until its implantation in the maternal endometrium.

Irrespective of this, though, this need to define when human life begins (see our article  is also due to the fact that during the early stages of human life — approximately during its first 14 days — this young embryo is subject to extensive and diverse threats that, in many cases, lead to its destruction (see HERE).

These threats affect embryos created naturally, mainly through the use of drugs or technical procedures used in the control of human fertility that act via an anti-implantation mechanism, especially intrauterine devices (as DIU); this is also the case of drugs used in emergency contraception, such as levonorgestrel or ulipristal-based drugs (see HERE), because both act via an anti-implantation mechanism in most of the time.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

Bioethics Blogs

Regenerative Medicine: Making Blood Stem Cells in the Lab

Caption: Arrow in first panel points to an endothelial cell induced to become hematopoietic stem cell (HSC). Second and third panels show the expansion of HSCs over time.
Credit: Raphael Lis, Weill Cornell Medicine, New York, NY

Bone marrow transplants offer a way to cure leukemia, sickle cell disease, and a variety of other life-threatening blood disorders.There are two major problems, however: One is many patients don’t have a well-matched donor to provide the marrow needed to reconstitute their blood with healthy cells. Another is even with a well-matched donor, rejection or graft versus host disease can occur, and lifelong immunosuppression may be needed.

A much more powerful option would be to develop a means for every patient to serve as their own bone marrow donor. To address this challenge, researchers have been trying to develop reliable, lab-based methods for making the vital, blood-producing component of bone marrow: hematopoietic stem cells (HSCs).

Two new studies by NIH-funded research teams bring us closer to achieving this feat. In the first study, researchers developed a biochemical “recipe” to produce HSC-like cells from human induced pluripotent stem cells (iPSCs), which were derived from mature skin cells. In the second, researchers employed another approach to convert mature mouse endothelial cells, which line the inside of blood vessels, directly into self-renewing HSCs. When these HSCs were transplanted into mice, they fully reconstituted the animals’ blood systems with healthy red and white blood cells.

As reported in Nature, both teams took advantage of earlier evidence showing that HSCs are formed during embryonic development from budding endothelial cells in the aorta.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

Bioethics Blogs

The Very Early Embryo & Its Moral Signifiance

by Andrew J. Prunty

As technology and biological research continue to develop in the twenty-first century, it is necessary to address and further define the ethical considerations of embryonic research and the appropriate rights that may limit the extent of human research on zygotes, blastocysts, and fetal scientific advancement. Because the area of harvesting embryonic stem cells remains significantly undefined, both legally and morally, there are vastly different opinions between researchers and bioethicists, mainly because of ethical limitations, on the rights that should be granted to cells with the potential to develop into human beings and the consequences of neglecting significant scientific research or advancement.

Current laws in the United States differ at the federal and state level, but there is no consistency in recognizing human embryos as humans, or affording them the same legal rights granted to a child; in fact, legal precedent actually detracts certain rights from developing embryos, favoring a human’s ability to destroy a potential human being (i.e. Roe v. Wade[i]) or the categorization of embryos as property (i.e. Davis v. Davis[ii], A.Z. v. B.Z.[iii], Marriage of Dahl[iv], or Reber v. Reiss[v]). These case law samples suggest the courts’ inability to reach a conclusion as to what is the status of an embryo.

The debate is not only circumscribed to matters of research, but to fundamental controversial and intertwined issues of bioethics such as: when life begins, embryonic stem cells, fetal rights, abortion, et cetera. All these topics are contentious and when one topic arises, they begin to comingle.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

Bioethics News

Ethical questions about mitochondrial replacement in humans. Three parents babies

We thus consider it necessary to establish a moratorium on their use in humans, at least until more is known about these aspects. If this knowledge is obtained, ethical questions would still remain to be resolved, among which we consider the most relevant to be those related to the dignity and identity of the human embryo.

Children with two mothers and a father

In January 2017, the prestigious scientific journal Bioethics published a special edition dedicated to the ethical aspects of nuclear transfer techniques aimed at preventing the transmission of mitochondrial diseases, a topic that we have extensively addressed in our Observatory (see HERE).

Its editorial, Ethics of mitochondrial replacement, starts by referring to the recent birth of the first baby resulting from these techniques (see HERE). It then provides a brief description of the main characteristics of mitochondrial diseases, which are inherited exclusively from the mother. It explains that mothers who carry mutations in their mitochondrial DNA (mtDNA) face the uncertainty of not knowing if their genetic children will or will not inherit a serious mitochondrial disease. However the emergence of mitochondrial replacement techniques (MRT) offers these mothers hope, as healthy mitochondria from a donor are used to replace those of the mother. These techniques are maternal spindle transfer (MST) and pronuclear transfer (PNT), which consist, respectively, in removing the nucleus from a healthy egg or zygote, which will keep its mitochondria. The nucleus of the mother’s oocyte (patient or carrier of the mutation) or of another zygote obtained by fertilising the mothers egg is then transferred into the enucleated oocyte or zygote.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

Bioethics Blogs

Do Extended Pluripotent Stem Cells Raise Ethical Issues?

On April 6, the journal Cell published work (subscription or online article purchase required) from the Salk Institute in San Diego, in which scientists have created a new “reprogrammed” stem cell.

These cells are called “extended pluripotent stem cells” or “EPS” cells.  They are different from embryonic stem (ES) cells, which are removed from intact embryos that arise from fertilization—typically requiring specific creation and destruction of an embryo.   Of course, ES cells can be human or non-human, depending on the source.

EPS cells are similar to “induced pluripotent stem cells,” or iPSCs, invented in 2006.  The latter are generated from adult skin cells that have been reprogrammed, using genetic alterations.

EPS cells may be made by reprogramming ES cells or skin cells or, if I understand the work correctly, iPSCs.  In this case, the reprogramming is done with a cocktail of chemicals in the lab.

But EPS cells are more capable than iPSCs.  Unlike iPSCs, which can give rise to many different types of cells but not all—including not a placenta and not an entire intact new individual—EPS cells can do all of that.  They are totipotent, meaning they can make all the cells of an individual from their species.  Moreover, they are quite long-lived in the laboratory.  EPS cells from one species—e.g., humans—can be placed into non-human (e.g., mouse) embryos to make hybrid animals that, it appears, survive quite well and can breed.  And, remarkably, the authors of the Cell paper report (again, if I understand correctly, and I think I do) that they were able to use a mouse EPS cell to give rise to a whole new mouse, not “just” a laboratory tissue hybrid.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

Bioethics News

New advances and challenges in the production of human-animal chimeras

They had overcome the obstacle of using human embryonic stem cells, but that even so, a ethical difficulty remained with the producing organs formed almost entirely of human cells in experimental animals.

It seems a little excessive that, in less than two months, we have dedicated three reports to the latest studies by Juan Carlos Izpisúa and his group. Nonetheless, we believe that the importance of his work merits this level of interest.

In our first report, we referred to a study published in Nature, which describes — among other breakthroughs — the production of human-animal chimeras in order to generate quasi-human organs for use in transplantation. In the report, we mentioned the ethical difficulties evident in the study as a result of the use of human embryonic stem cells.

In the second, we discussed the new steps taken in the production of human organs in animals, in connection with an interview by Izpisúa published in Investigación y Ciencia (the Spanish version of Scientific American). In the interview, Izpisúa particularly stressed that, from an ethical point of view, they had overcome the obstacle of using human embryonic stem cells, but that even so, a potential ethical difficulty remained with the possibility of producing organs formed almost entirely of human cells in experimental animals.

Now, we evaluate these experiments by analysing the latest findings published in an article in scientific journal Cell (see HERE).  We also discuss another paper by a different research group, in which the authors also describe the production of human-animal chimeras, likewise with the intention of producing organs for transplantation.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.

Bioethics Blogs

Public funds authorised for production of chimeras (human-animal hybrids)

In September 2005, the dedication of public financial aid by the National Health Institutes for experiments on transferring human stem cells to animal embryos to produce chimeras was banned. However, on 4 August this year, this ban was lifted for certain experiments, and it was proposed that a panel of experts be created to evaluate the ethical problems with chimeras production.

The ban also prohibits the transfer of human stem cells before the nervous system begins to form in the recipient animal embryo, a measure aimed at limiting the implantation of human stem cells in the brain of the transplanted animal.

Chimeras are currently being used to study the early stages of embryonic development and various human diseases, although the main aim is undoubtedly to produce animals with human organs for human transplants (Nature, 536; 135, 2016). This regulation is expected to be applied from January 2017.

We have already referred to these practices (see HERE) which, from a bioethical perspective, can be labelled as clearly utilitarian.

La entrada Public funds authorised for production of chimeras (human-animal hybrids) aparece primero en Observatorio de Bioética, UCV.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.