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1) Grow the endometrium using stem cells (It has already been done (Cambridge, 2017))
2) Attach the embryo to it and allow the placenta to grow.
In 2003, there was a researcher at Columbia who did something like this, but there was no technology to create endometrium tissue. She used some donated infertile tissues, but the rat embryos did attach to it and grow, although the growth itself was retarded. That's understandable since the endometrium has some special secretory functions. So what could be the issues with the method I have suggested?
A lot of the new approaches seem to involve artificial placentas , which are probably not very easy to create. The don't seem to be the most obvious approach either. I think a large part of the issue is that you won't get funding if you say you want to create an artificial womb, because of the ethical issues involved. So you have to show some connection to neonatal stuff and hence the easiest approach is neglected. Am I right in this assessment?
In the paper you have (indirectly) linked, the authors describe cultures of organoids. Despite their fancy name and the catchy title of some news article about them, organoids are very far from being mini organs. They are a bunch of cells that grow in a 3D structure and they may resemble an organ in term of cell type and some cell-to-cell communication, but that's pretty much all. Mind that an organ is vascularized, organoids are not. The vascularization allows for organ-to-organ communication, like the delivery of brain-made hormones, for example. Such communication is extremely important during the embryo development, it's not only the endometrium missing here. I am not saying that is impossible to make artificial wombs, but organoids alone will not be sufficient.
Artificial 'womb' unlocks secrets of early embryo development
Pioneering work by a leading University of Nottingham scientist has helped reveal for the first time a vital process in the development of the early mammalian embryo.
A team led by Professor of Tissue Engineering, Kevin Shakesheff, has created a new device in the form of a soft polymer bowl which mimics the soft tissue of the mammalian uterus in which the embryo implants. The research has been published in the journal Nature Communications.
This new laboratory culture method has allowed scientists to see critical aspects of embryonic development that have never been seen in this way before. For the first time it has been possible to grow embryos outside the body of the mother, using a mouse model, for just long enough to observe in real time processes of growth during a crucial stage between the fourth and eighth days of development.
Professor Shakesheff said: "Using our unique materials and techniques we have been able to give our research colleagues a previously unseen view of the incredible behaviour of cells at this vital stage of an embryo's development. We hope this work will unlock further secrets which could improve medical treatments that require tissues to regenerate and also open up more opportunities to improve IVF. In the future we hope to develop more technologies which will allow developmental biologists to understand how our tissue forms."
In the past it has only been possible to culture a fertilised egg for four days as it grows from a single cell into a blastocyst, a ball of 64 cells comprising stem cells which will form the body, and extra-embryonic cells which form the placenta and control stem cell development as the embryo develops. But scientists' knowledge of events at a cellular level after four days, when, to survive, the blastocyst has to implant into the mother's womb, has up to now been limited. Scientists have had to rely on snap shots taken from embryos removed from the living uterus at different stages of development.
Now, thanks to The University of Nottingham team's newly developed culture environment, scientists at Cambridge University have been able to observe and record new aspects of the development of the embryo after four days. Most importantly they have been able to see at first hand the process which is the first step in the formation of the head, involving pioneer cells moving a large distance (for a cell) within the embryo. They have observed clusters of extra-embryonic cells which signal where the head of the embryo should form. To track these cells in mouse embryos they have used a gene expressed only in this 'head' signalling region marked by a protein which glows.
In this way they have been able to work out that these cells come from one or two cells at the blastocyst stage whose progeny ultimately cluster together in a specific part of the embryo, before collectively migrating to the position at which they signal head development. The cells that lead this migration appear to have an important role in leading the rest and acting as pioneers.
This new breakthrough is part of a major research effort at Nottingham to learn how the development of the embryo can teach us how to repair the adult body. The work is led by Professor Kevin Shakesheff with funding from European Research Council.
Professor Shakesheff added: "Everyone reading this article grew themselves from a single cell. With weeks of the embryo forming all of the major tissues and organs are formed and starting to function. If we could harness this remarkable ability of the human body to self-form then we could design new medical treatments that cure diseases that are currently untreatable. For example, diseases and defects of the heart could be reversed if we could recreate the process by which cardiac muscle forms and gets wired into the blood and nervous system."
Professor Shakesheff's work was carried out in collaboration with scientists led by Professor Magdalena Zernicka-Goetz at the Gurdon Institute, Cambridge University.
A stem cell method for creating artificial wombs? - Biology
For the first time, an artificially create a mouse embryo has successfully passed a critical developmental milestone in the lab.
Gastrulation is a process during embryonic development in which the embryo transforms from being a single layer of cells to three layers, known as endoderm, mesoderm and ectoderm. This process is essential for the development of an organism and has never before been demonstrated in an artificially created embryo.
'Our artificial embryos underwent the most important event in life in the culture dish. They are now extremely close to real embryos,' said Professor Magdalena Zernicka-Goetz, who led the study at the University of Cambridge.
The researchers had previously worked on a simpler structure of a mouse embryo consisting of two types of stem cells and a 3D jelly scaffold. In the new study &ndash published in Nature Cell Biology &ndash they used all three types of stem cells: embryonic stem cells that will form the future organism, extraembryonic trophoblast cells that form the placenta and primitive endoderm cells that develop into the yolk sac for nutrient supply.
'Proper gastrulation in normal development is only possible if you have all three types of stem cells. In order to reconstruct this complex dance, we had to add the missing third stem cell,' said Professor Zernicka-Goetz. 'By replacing the jelly that we used in earlier experiments with this third type of stem cell, we were able to generate structures whose development was astonishingly successful.'
The embryos that resulted from these experiments underwent gastrulation in a very similar way to real mouse embryos with respect to timing, architecture and gene pattern activity, leading to a display of the three body layers of all animals.
The researchers hope that this new model will be of use to study early human embryonic development. Current British regulations only allow for the study of human embryos for the first 14 days of their development after which they must be destroyed. Artificial embryos using human cells could possibly allow for analysis of embryos beyond this point.
'The early stages of embryo development are when a large proportion of pregnancies are lost and yet it is a stage that we know very little about,' said Professor Zernicka-Goetz. 'Now we have a way of simulating embryonic development in the culture dish, so it should be possible to understand exactly what is going on during this remarkable period in an embryo's life, and why sometimes this process fails.'
Stem cells create early human embryo structure in advance for fertility research
Left is stem cell embryo model right is nature human embryo. Credit: University of Exeter
Exeter scientists have discovered a simple, efficient way to recreate the early structure of the human embryo from stem cells in the laboratory. The new approach unlocks news ways of studying human fertility and reproduction.
Stem cells have the ability to turn into different types of cell. Now, in research published in Cell Stem Cell and funded by the Medical Research Council, scientists at the University of Exeter's Living Systems Institute, working with colleagues from the University of Cambridge, have developed a method to organize lab-grown stem cells into an accurate model of the first stage of human embryo development.
The ability to create artificial early human embryos could benefit research into infertility, by furthering understanding of how embryos develop, and the conditions needed to avoid miscarriage and other complications. The embryo models can also be used to test conditions that may improve the development of embryos in assisted conception procedures such as IVF.
The new discovery comes after the team found that a human stem cell was able to generate the founding elements of a blastocyst—the very early formation of an embryo after a fertilized egg divides. Professor Austin Smith, Director of the University of Exeter's Living Systems Institute, said: "Finding that stem cells can create all the elements of an early embryo is a revelation. The stem cells come from a fully-formed blastocyst, yet they are able to recreate exactly the same whole embryo structure. This is quite remarkable and unlocks exciting possibilities for learning about the human embryo."
Left is stem cell embryo model right is nature human embryo. Credit: University of Exeter
The research has the potential to significantly advance understanding. Few human embryos are available for study, so until now, scientists have largely focussed on animal research, particularly mice, despite the fact that their reproductive systems differ significantly from humans. Around one in seven couples in the UK has difficulty conceiving.
In the research, the team arranged the stem cells into clusters and briefly introduced two molecules known to influence how cells behave in early development. They found that 80 percent of the clusters organized themselves after 3 days into structures that look remarkably like the blastocyst stage of an embryo—a ball of around 200 cells that forms from the fertilized egg after 6 days. The team went on to show that the artificial embryos have the same active genes as the natural embryo.
The study was directed by Dr. Ge Guo, of the University of Exeter's Living Systems Institute, said: "Our new technique provides for the first time a reliable system to study early development in humans without using embryos. This shouldn't be seen as a move towards producing babies in a laboratory, but rather as an important research tool that could benefit IVF and infertility studies."
The next stage for the researchers is to understand how to develop the artificial embryos a few days further to study the critical period when an embryo would implant into the womb, which is when many embryos fail to develop properly.
The paper is entitled "Naive stem cell blastocyst model captures human embryo lineage segregation," and is published in Cell Stem Cell.
Advanced mouse embryos grown outside the uterus
Credit: Pixabay/CC0 Public Domain
To observe how a tiny ball of identical cells on its way to becoming a mammalian embryo first attaches to an awaiting uterine wall and then develops into nervous system, heart, stomach and limbs: This has been a highly-sought grail in the field of embryonic development for nearly 100 years. Prof. Jacob Hanna of the Weizmann Institute of Science and his group have now accomplished this feat. The method they created for growing mouse embryos outside the womb during the initial stages after embryo implantation will give researchers an unprecedented tool for understanding the development program encoded in the genes, and it may provide detailed insight into birth and developmental defects as well as those involved in embryo implantation. The results of this research were published in Nature.
Hanna, who is in the Institute's Molecular Genetics Department, explains that much of what is known about mammalian embryonic development today comes either from observing the process in non-mammals like frogs or fish that lay transparent eggs, or by obtaining static images from dissected mouse embryos and adding them together. The idea of growing early embryos outside the uterus has been around since before the 1930s, he adds, but experiments based on these proposals had limited success and the embryos tended to be abnormal.
Hanna's team decided to renew that effort in order to advance the research in his lab, which focuses on the way the development program is enacted in embryonic stem cells. Over seven years, through trial and error, fine-tuning and double-checking, his team came up with a two-step process in which they were able to grow normally developing mouse embryos outside the uterus for six days—around a third of their 20-day gestation—by which time the embryos already had a well-defined body plan and visible organs. "To us, that is the most mysterious and the most interesting part of embryonic development, and we can now observe it and experiment with it in amazing detail," say Hanna.
The research was led by Alejandro Aguilera-Castrejon, Dr. Bernardo Oldak, the late Dr. Rada Massarwa and Dr. Noa Novershtern in Hanna's lab and Dr. Itay Maza, a former student of Hanna's now in the Rambam Health Care Campus of the Technion—Israel Institute of Technology.
For the first step, which lasted around two days, the researchers started with several-day old mouse embryos—right after they would have implanted in the uterus. At this stage the embryos were balls consisting of 250 identical stem cells. These were placed on a special growth medium in a laboratory dish and the team got the balls to attach to this medium as they would to the uterine wall. With this step, they succeeded in duplicating the first stage of embryonic development, in which the embryo doubles and triples in size, as it differentiates into three layers: inner, middle and outer.
Beyond two days, as the embryos entered the next developmental stage—the formation of organs from each of the layers—they needed additional conditions. For this second step, the scientists placed the embryos in a nutrient solution in tiny beakers, setting the beakers on rollers that kept the solutions in motion and continually mixed. That mixing seems to have helped keep the embryos, which were growing without maternal blood flow to the placenta, bathed in the nutrients. In addition to carefully regulating the nutrients in the beakers, the team learned in further experiments to closely control the gases, oxygen and carbon dioxide—not just the amounts, but the gas pressure as well.
To check whether the developmental processes they were observing throughout the two steps were normal, the team conducted careful comparisons with embryos removed from pregnant mice in the relevant time period, showing that both the separation into layers and the organ formation were all but identical in the two groups. In subsequent experiments, they inserted into the embryos genes that labeled the growing organs in fluorescent colors. The success of this attempt suggested that further experiments with this system involving various genetic and other manipulations should produce reliable results. "We think you can inject genes or other elements into the cells, alter the conditions or infect the embryo with a virus, and the system we demonstrated will give you results consistent with development inside a mouse uterus," says Hanna.
"If you give an embryo the right conditions, its genetic code will function like a pre-set line of dominos, arranged to fall one after the other," he adds. "Our aim was to recreate those conditions, and now we can watch, in real time, as each domino hits the next one in line." Among other things, explains Hanna, the method will lower the cost and speed up the process of research in the field of developmental biology, as well as reducing the need for lab animals.
In fact, the next step in Hanna's lab will be to see if they can skip the step of removing embryos from pregnant mice. He and his team intend to try to create artificial embryos made from stem cells for use in this research. Among other things, they hope to put their new method to work to answer such questions as why so many pregnancies fail to implant, why the window for implantation is so short, how stem cells gradually lose their "stemness" as differentiation progresses and what conditions in gestation may later lead to developmental disorders.
Artificial womb improves survival rates for the very smallest
Credit: Eindhoven University of Technology
An artificial womb to enhance the chances for survival and quality of life of extremely premature babies by mimicking the conditions of a real womb. Whereas a year ago during the Dutch Design Week there was only an initial design, in the next years the focus will be on working towards the first (pre)clinical tests. Researchers Prof. Frans van de Vosse and Prof. Guid Oei of TU/e and MMC are the initiators of this research.
Because the lungs of extremely premature babies are not yet sufficiently developed, the artificial womb will eventually have to replace the incubator and artificial ventilation. This is much more natural, because this technique approaches the conditions of a real womb much more closely. "Using this artificial womb, we want to help extremely premature babies through the critical period of 24 to 28 weeks," says Guid Oei, gynecologist working at MMC and part-time professor at TU/e.
The chances of survival of these babies are small about half die at 24 weeks of pregnancy. And the surviving babies often have life-long problems with chronic conditions such as brain damage, impaired lung function and/or retina problems with possible blindness as a result. "With each day that the growth of a 24-week fetus in an artificial womb is prolonged, the chance of survival without complications increases. If we can extend the fetal growth of these children in the artificial womb to 28 weeks, the risk of premature death is three times as low," says Oei.
Testing with computer models
Frans van de Vosse, Professor of Cardiovascular Biomechanics at the Department of Biomedical Engineering at TU/e: "The artificial womb is filled with fluid just like the natural womb. The exchange of oxygen and nutrients takes place via the umbilical cord, which is connected to an artificial placenta. The baby's condition is continuously monitored. Such as heart rate and oxygen supply but also brain and muscle activity. We use advanced computer models that simulate the baby's condition and the outcome of interventions that can be performed via the artificial womb. In this way, the computer simulations form a decision support system that can be used to support the doctor to make very quick decisions about the settings of the artificial womb."
To test the artificial womb before it is used in clinical tests, TU/e researchers Prof. Loe Feijs and Frank Delbressine are developing a lifelike dummy, or so-called simulation manikin that mimics a premature fetus in an Intensive Care environment.
Eight years to first human test
"Over the next eight years, we're going to develop these technologies, and come up with the first prototypes of the artificial womb. Once these have been carefully tested, we want to help the first extremely premature baby in our artificial mother in eight years' time in the first clinical tests. That's quite the challenge," says Oei.
But in developing the technique of the artificial womb alone, the research team is not yet finished. In order to be able to use this new technology in birth care, many questions still need to be answered. What is the optimal birth procedure for the baby into the artificial womb? And what does the birth from the artificial womb look like? The team will study these dilemmas using simulation manikins of the baby, simulation models of the artificial womb and simulation models of mother and child.
Ethics and public debate
Another important part of the research concerns the many ethical dilemmas, legal issues and public debate about, among other things, the desirability of an artificial womb, the bond between mother and child and the step from prototype to human testing. During the complete development of the artificial womb and the related procedures, collaboration will therefore take place with ethicists and lawyers, but also with discussion groups including midwives. Together, this team of specialists will come up with the best design of the artificial womb, the most ideal research procedure and a transparent working method.
V. Fetal Stem Cells
Pluripotent stem cells can be derived from fetal tissue after abortion. However, use of fetal tissue is ethically controversial because it is associated with abortion, which many people object to. Under federal regulations, research with fetal tissue is permitted provided that the donation of tissue for research is considered only after the decision to terminate pregnancy has been made. This requirement minimizes the possibility that a woman’s decision to terminate pregnancy might be influenced by the prospect of contributing tissue to research. Currently there is a phase 1 clinical trial in Batten’s disease, a lethal degenerative disease affecting children, using neural stem cells derived from fetal tissue (43,44).
Scientists Create Immature Human Eggs From Stem Cells
Immature human eggs (pink) were created by Japanese researchers using stem cells that were derived from blood cells.
Scientists say they have taken a potentially important — and possibly controversial — step toward creating human eggs in a lab dish.
A team of Japanese scientists turned human blood cells into stem cells, which they then transformed into very immature human eggs.
The eggs are far too immature to be fertilized or make a baby. And much more research would be needed to create eggs that could be useful — and safe — for human reproduction.
But the work, reported Thursday in the journal Science, is seen by other scientists as an important development.
"For the first time, scientists have been able to convincingly demonstrate that we are able to make eggs — very immature eggs," says Amander Clark, a developmental biologist at UCLA who wasn't involved in the research.
The technique might someday help millions of people suffering from infertility because of cancer treatments or other reasons, Clark says.
But the prospect of being able to mass-produce human eggs in labs raises a host of societal and ethical issues.
Theoretically, babies someday could be made from the blood, hair or skin cells of children, grandmothers, even deceased people. "So there are some very weird possibilities emerging," says Ronald Green, a Dartmouth bioethicist.
People could even potentially make babies from cells stolen from unwitting celebrities, such as skin cells left behind on a soda can or follicles from hair clipped at a salon.
"A woman might want to have George Clooney's baby," Green says. "And his hairdresser could start selling his hair follicles online. So we suddenly could see many, many progeny of George Clooney without his consent."
For years, scientists have been trying to make eggs and sperm from stem cells.
In 2012, Mitinori Saitou at Kyoto University and his colleagues reported they produced mature mouse eggs and sperm from stem cells, and used them to breed healthy mouse pups.
But scientists have been stymied in their attempts to get even close to those results for humans. "The field has been stalled for a number of years at this bottleneck," Clark says.
But Saitou and his colleagues kept at it, and they described how they achieved success in their Science paper.
First, the scientists used a well-established method to turn adult human blood cells into induced pluripotent stem cells, which have the ability to become any cell in the body.
But the key, apparently, was putting the induced human pluripotent stem cells into miniature ovaries they created in the lab from mouse embryonic cells.
"They created a tiny little artificial ovary and inside that little reconstituted ovary were these very immature human egg cells. So the entire experiment happened entirely within an incubator within a laboratory," Clark says.
In their paper, the Japanese scientists say the next step will be to try to make mature human eggs and produce human sperm this way.
"It's the beginning of a paradigm change," says Kyle Orwig, a professor in the department of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine.
In addition to helping infertile people, such a development could enable gay couples to have babies with sperm and eggs made from their own skin cells.
But such a possibility would also have much broader implications, say others following the field.
"If we can make human eggs and sperm from skin cells it opens up an enormous number of possibilities for changing how humans reproduce," says Hank Greely, a bioethicist at Stanford who wrote The End of Sex and the Future of Reproduction.
For example, easy access to eggs might mean it would become routine to scan the DNA of embryos before anyone tries to have a baby.
"Doing genetic testing basically on a large chunk of every generation of babies before they even become fetuses — while they're still embryos — and having parents and potentially governments pick and chose which embryos go on to become babies — that has lots of implications," Greely says.
Correction Sept. 21, 2018
An earlier version of this story misspelled Amander Clark's first name as Amanda.
Stem cells have been the object of much excitement and controversy amongst both scientists and the general population. Surprisingly, though, not everybody understands the basic properties of stem cells, let alone the fact that there is more than one type of cell that falls within the “stem cell” category. Here, I’ll lay out the basic concepts of stem cell biology as a background for understanding the stem cell research field, where it is headed, and the enormous promise it offers for regenerative medicine.
Stem cells come in different flavors of potency
Fertilization of an egg cell by a sperm cell results in the generation of a zygote, the single cell that, upon a myriad of divisions, gives rise to our whole body. Because of this amazing developmental potential, the zygote is said to be totipotent. Along the way, the zygote develops into the blastocyst, which implants into the mother’s uterus. The blastocyst is a structure comprising about 300 cells that contains two main regions: the inner cell mass (ICM) and the trophoblast. The ICM is made of embryonic stem cells (ES cells), which are referred to as pluripotent. They are able to give rise to all the cells in an embryo proper, but not to extra-embryonic tissues, such as the placenta. The latter originate from the trophoblast .
Even though it is hard to pinpoint exactly when or by whom what we now call “stem cells” were first discovered, the consensus is that the first scientists to rigorously define the key properties of a stem cell were Ernest McCulloch and James Till. In their pioneering work in mice in the 1960s, they discovered the blood-forming stem cell, the hematopoietic stem cell (HSC) [2, 3]. By definition, a stem cell must be capable of both self-renewal (undergoing cell division to make more stem cells) and differentiation into mature cell types. HSCs are said to be multipotent, as they can still give rise to multiple cell types, but only to other types of blood cells (see Figure 1, left column). They are one of many examples of adult stem cells, which are tissue-specific stem cells that are essential for organ maintenance and repair in the adult body. Muscle, for instance, also possesses a population of adult stem cells. Called satellite cells, these muscle cells are unipotent, as they can give rise to just one cell type, muscle cells.
Therefore, the foundations of stem cell research lie not with the famous (or infamous) human embryonic stem cells, but with HSCs, which have been used in human therapy (such as bone marrow transplants) for decades. Still, what ultimately fueled the enormous impact that the stem cell research field has today is undoubtedly the isolation and generation of pluripotent stem cells, which will be the main focus of the remainder of the text.
Figure 1: Varying degrees of stem cell potency. Left: The fertilized egg (totipotent) develops into a 300-cell structure, the blastocyst, which contains embryonic stem cells (ES cells) at the inner cell mass (ICM). ES cells are pluripotent and can thus give rise to all cell types in our body, including adult stem cells, which range from multipotent to unipotent. Right: An alternative route to obtain pluripotent stem cells is the generation of induced pluripotent stem cells (iPS cells) from patients. Cell types obtained by differentiation of either ES cell (Left) or iPS cells (Right) can then be studied in the dish or used for transplantation into patients. Figure drawn by Hannah Somhegyi.
Reprogramming committed adult cells into stem cells: from frog to man
Martin Evans (Nobel Prize, 2007) and Matt Kauffman were the first to identify, isolate and successfully culture ES cells using mouse blastocysts in 1981 . This discovery opened the doors to the creation of “murine genetic models,” which are mice that have had one or several of their genes deleted or otherwise modified to study their function in disease . This is possible because scientists can modify the genome of a mouse in its ES cells and then inject those modified cells into mouse blastocysts. This means that when the blastocyst develops into an adult mouse, every cell its body will have the modification of interest.
The desire to use stem cells’ unique properties in medicine was greatly intensified when James Thomson and collaborators first isolated ES cells from human blastocysts . For the first time, scientists could, in theory, generate all the building blocks of our body in unlimited amounts. It was possible to have cell types for testing new therapeutics and perhaps even new transplantation methods that were previously not possible. Yet, destroying human embryos to isolate cells presented ethical and technical hurdles. How could one circumvent that procedure? Sir John Gurdon showed in the early 1960s that, contrary to the prevalent belief back then, cells are not locked in their differentiation state and can be reverted to a more primitive state with a higher developmental potential. He demonstrated this principle by injecting the nucleus of a differentiated frog cell into an egg cell from which the nucleus had been removed. (This is commonly known as reproductive cloning, which was used to generate Dolly the Sheep.) When allowed to develop, this egg gave rise to a fertile adult frog, proving that differentiated cells retain the information required to give rise to all cell types in the body. More than forty years later, Shinya Yamanaka and colleagues shocked the world when they were able to convert skin cells called fibroblasts into pluripotent stem cells by altering the expression of just four genes . This represented the birth of induced pluripotent stem cells, or iPS cells (see Figure 1, right column). The enormous importance of these findings is hard to overstate, and is perhaps best illustrated by the fact that, merely six years later, Gurdon and Yamanaka shared the Nobel Prize in Physiology or Medicine 2012 .
The future: stem cell-based personalized regenerative medicine?
Since the generation of iPS cells was first reported, the stem cell ﬁeld has expanded at an unparalleled pace. Today, these cells are the hope of personalized medicine, as they allow one to capture the unique genome of each individual in a cell type that can be used to generate, in principle, all cell types in our body, as illustrated on the right panel of Figure 1. The replacement of diseased tissues or organs without facing the barrier of immune rejection due to donor incompatibility thus becomes approachable in this era of iPS cells and is the object of intense research .
The first proof-of-principle study showing that iPS cells can potentially be used to correct genetic diseases was carried out in the laboratory of Rudolf Jaenisch. In brief, tail tip cells from mice with a mutation causing sickle cell anemia were harvested and reprogrammed into iPS cells. The mutation was then corrected in these iPS cells, which were then differentiated into blood progenitor cells and transplanted back into the original mice, curing them . Even though iPS cells have been found not to completely match ES cells in some instances, detailed studies have failed to find consistent differences between iPS and ES cells . This similarity, together with the constant improvements in the efficiency and robustness of generating iPS cells, provides bright prospects for the future of stem cell research and stem cell-based treatments for degenerative diseases unapproachable with more conventional methods.
Leonardo M. R. Ferreira is a graduate student in Harvard University’s Department of Molecular and Cellular Biology
 Becker, A. J., McCulloch, E.A., Till, J.E. Cytological demonstration of the clonal nature of spleen colonies derived from transplanted mouse marrow cells. Nature 1963. 197: 452-4
 Siminovitch, L., McCulloch, E.A., Till, J.E. The distribution of colony-forming cells among spleen colonies. J Cell Comp Physiol 1963, 62(3): 327-336
 Evans, M. J. and Kaufman, M. Establishment in culture of pluripotential stem cells from mouse embryos. Nature 1981, 292: 151–156
 Simmons, D. The Use of Animal Models in Studying Genetic Disease: Transgenesis and Induced Mutation. Nature Education 2008, 1(1):70
 Thomson, J. A. et al. Embryonic stem cell lines derived from human blastocysts. Science 1998, 282(5391): 1145-1147
 Takahashi, K. and Yamanaka S. Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 2006. 126(4): 663-76
 “The Nobel Prize in Physiology or Medicine 2012”:
 Ferreira, L.M.R. and Mostajo-Radji, M.A. How induced pluripotent stem cells are redefining personalized medicine. Gene 2013. 520(1): 1-6  Hanna J. et al. Treatment of sickle cell anemia mouse model with iPS cells generated from autologous skin. Science 2007. 318: 1920-1923
 Yee, J. Turning Somatic Cells into Pluripotent Stem Cells. Nature Education 2010. 3(9):25
A stem cell method for creating artificial wombs? - Biology
Artificial cells have attracted much attention as substitutes for natural cells. There are many different forms of artificial cells with many different definitions. They can be integral biological cell imitators with cell-like structures and exhibit some of the key characteristics of living cells. Alternatively, they can be engineered materials that only mimic some of the properties of cells, such as surface characteristics, shapes, morphology, or a few specific functions. These artificial cells can have applications in many fields from medicine to environment, and may be useful in constructing the theory of the origin of life. However, even the simplest unicellular organisms are extremely complex and synthesis of living artificial cells from inanimate components seems very daunting. Nevertheless, recent progress in the formulation of artificial cells ranging from simple protocells and synthetic cells to cell-mimic particles, suggests that the construction of living life is now not an unrealistic goal. This review aims to provide a comprehensive summary of the latest developments in the construction and application of artificial cells, as well as highlight the current problems, limitations, challenges and opportunities in this field.