Beating Heart Created In Laboratory: Method May Revolutionize How Organ Tissues Are Developed

By using a process called whole organ decellularization, scientists from the University of Minnesota Center for Cardiovascular Repair grew functioning heart tissue by taking dead rat and pig hearts and reseeding them with a mixture of live cells. The research will be published online in the January 13 issue of Nature Medicine.

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Researchers create mathematical model of fruit fly eyes

Many researchers have tried to create a mathematical model of how cells pack together to form tissue, but most models have many different complicated factors, and no model is universal.

Researchers at Northwestern University have now created a functional equation — using only two parameters — to show how cells pack together to create the eyes of Drosophila, better known as the fruit fly. They hope that the pared-down equation can be applied to different kinds of tissues, leading to advances in regenerative medicine.

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Researchers discover human embryonic stem cells are the ultimate perpetual fuel cell

A startling discovery on the development of human embryonic stem cells by scientists at McMaster University will change how future research in the area is done.

An article published in the prestigious scientific journal Nature this week reports on a new understanding of the growth of human stem cells. It had been thought previously that stem cells are directly influenced by cells in the local environment or ‘niche’, but the situation may be more complex. Human embryonic stem cells are perpetual machines that generate fuel for life.

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Scientists succeed in hair follicle regeneration in an animal model

Researchers at the University of Pennsylvania School of Medicine have found that hair follicles in adult mice regenerate by re-awakening genes once active only in developing embryos. These findings provide unequivocal evidence for the first time that, like other animals such as newts and salamanders, mammals have the power to regenerate. These findings are published in the May 17 issue of Nature.

A better understanding of this process could lead to novel treatments for hair loss, other skin and hair disorders, and wounds.

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Scientists identify critical gene factor in heart development

Researchers at the Gladstone Institute of Cardiovascular Disease (GICD) announced they have identified a critical genetic factor in the control of many aspects of heart form and function. As reported in the journal Cell, scientists in the lab of Deepak Srivastava, MD, have successfully deleted a genetic factor, called a microRNA, in animal models to understand the role it plays in cardiovascular differentiation and development.
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Scientists unlock mystery of embryonic stem cell signaling pathway

A newly discovered small molecule called IQ-1 plays a key role in preventing embryonic stem cells from differentiating into one or more specific cell types, allowing them to instead continue growing and dividing indefinitely, according to research performed by a team of scientists who have recently joined the stem-cell research efforts at the Keck School of Medicine of the University of Southern California.
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Scientists create mice with enhanced color vision

Researchers at the Johns Hopkins School of Medicine and their colleagues have found that mice simply expressing a human light receptor in addition to their own can acquire new color vision, a sign that the brain can adapt far more rapidly to new sensory information than anticipated.

This work, appearing March 23 in Science, also suggests that when the first ancestral primate inherited a new type of photoreceptor more than 40 million years ago, it probably experienced immediate color enhancement, which may have allowed this trait to spread quickly.
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Scientists Make Major Discovery to Advance Regenerative Medicine

Scientists at Forsyth may have moved one step closer to regenerating human spinal cord tissue by artificially inducing a frog tadpole to re-grow its tail at a stage in its development when it is normally impossible. Using a variety of methods including a kind of gene therapy, the scientists altered the electrical properties of cells thus inducing regeneration. This discovery may provide clues about how bioelectricity can be used to help humans regenerate.
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Scientists develop new procedure to differentiate human embryonic stem cells

Scientists have developed a new procedure for the differentiation of human embryonic stem cells, with which they have created the first transplantable source of lung epithelial cells.

The method involves the use of protein markers under the control of cell-specific promoters to convert undifferentiated human embryonic stem cells into highly-specialized cells. The human embryonic stem cells were cultured on specially coated dishes and transfected with a lung epithelial gene regulator of a drug selection gene.
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How stem cells are regulated

Researchers from Biotech Research & Innovation Centre (BRIC) at University of Copenhagen have identified a new group of proteins that regulate the function of stem cells. The results are published in the new issue of Cell.
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Researchers replace organ in adult mice using ‘single-parent’ stem cells

Researchers at the University of Pennsylvania School of Veterinary Medicine have derived uniparental embryonic stem cells – created from a single donor’s eggs or two sperm – and, for the first time, successfully used them to repopulate a damaged organ with healthy cells in adult mice. Their findings demonstrate that single-parent stem cells can proliferate normally in an adult organ and could provide a less controversial alternative to the therapeutic cloning of embryonic stem cells.
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Master switches found for adult blood stem cells

Scientists have found a set of “master switches” that keep adult blood-forming stem cells in their primitive state. Unlocking the switches’ code may one day enable scientists to grow new blood cells for transplant into patients with cancer and other bone marrow disorders.

The scientists located the control switches not at the gene level, but farther down the protein production line in more recently discovered forms of ribonucleic acid, or RNA. MicroRNA molecules, once thought to be cellular junk, are now known to switch off activity of the larger RNA strands which allow assembly of the proteins that let cells grow and function.
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Scientists discover early key to regeneration

Science may be one step closer to understanding how a limb can be grown or a spinal cord can be repaired. Scientists at The Forsyth Institute have discovered that some cells have to die for regeneration to occur. This research may provide insight into mechanisms necessary for therapeutic regeneration in humans, potentially addressing tissues that are lost, damaged or non- functional as a result of genetic syndromes, birth defects, cancer, degenerative diseases, accidents, aging and organ failure. Through studies of the frog (Xenopus) tadpole, the Forsyth team examined the cellular underpinnings of regeneration.
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Researchers create genetically matched embryonic stem cells for transplantation

Researchers at Children’s Hospital Boston report a new and efficient strategy, using eggs alone, for creating mouse embryonic stem cells that can be transplanted without the risk of rejection because the cells are compatible with the recipient’s immune system. The findings are published online in the journal Science on December 14.

Though done in mice, the work establishes the principle of using unfertilized eggs as a source of customized embryonic stem cells that are genetically matched to the egg donor at the genes that control recognition of cells by the immune system, making them potentially useful for transplantation therapies. There are several caveats, including the fact that only females could benefit from this technique, donating their own eggs to generate the stem cells, and concerns that the tissues derived from this special type of embryonic stem cells might not function normally.
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How does a zebrafish grow a new tail?

If a zebrafish loses a chunk of its tail fin, it’ll grow back within a week. Like lizards, newts, and frogs, a zebrafish can replace surprisingly complex body parts. A tail fin, for example, has many different types of cells and is a very intricate structure. It is the fish version of an arm or leg.

The question of how cold-blooded animals re-grow missing tails and other appendages has fascinated veterinary and medical scientists. They also wonder if people, and other warm-blooded animals that evolved from these simpler creatures, might still have untapped regenerative powers hidden in their genes.
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Researchers map out networks that determine cell fate

A two-step process appears to regulate cell fate decisions for many types of developing cells, according to researchers from the University of Chicago.

This finding sheds light on a puzzling behavior. For some differentiating stem cells, the first step leads not to a final decision but to a new choice. In response to the initial chemical signal, these cells take on the genetic signatures of two different cell types. It often requires a second signal for them to commit to a single cellular identity.

In the Aug. 25 2006 issue of Cell, the researchers, working with hematopoietic stem cells, which give rise to the many types of blood cells, show how “pioneer transcription factors” trigger the first step, pushing these stem cells towards this mixed lineage, midway between two related cell types — in this case between a macrophage and a neutrophil.
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Cell transplants restore sight in mice

Scientists have successfully transplanted light-sensing cells called photoreceptors, which are immature retinal stem cells, directly into the eyes of mice and restored their visual function. The mice had eye damage similar to that seen in many human eye diseases. Experts welcomed the study, published in the magazine Nature, saying it was “stunning” research.

The achievement is based on a novel technology in which the cells are introduced at a particular stage in their development. It was carried out at the London Institute of Ophthalmology using a novel approach developed at the University of Michigan Kellogg Eye Center to tag rod precursor cells and prepare them for transplantation.

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Stretching bone marrow stem cells pushes them towards becoming blood vessel

When stretched, a type of adult stem cell taken from bone marrow can be nudged towards becoming the type of tissue found in blood vessels, according to a new study by bioengineers at the University of California, Berkeley.

Researchers placed mesenchymal stem cells onto a silicone membrane that was stretched longitudinally once every second. It was a cellular workout routine that helped point the bone marrow stem cell in the direction of becoming the smooth muscle tissue of vascular walls.

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Researchers map out networks that determine cell fate

A two-step process appears to regulate cell fate decisions for many types of developing cells, according to researchers from the University of Chicago.

This finding sheds light on a puzzling behavior. For some differentiating stem cells, the first step leads not to a final decision but to a new choice. In response to the initial chemical signal, these cells take on the genetic signatures of two different cell types. It often requires a second signal for them to commit to a single cellular identity.
Continue reading “Researchers map out networks that determine cell fate”

Mapping system tells skin cells whether to become scalp or palm tissues

Global-positioning system aficionados know that it’s possible to precisely define any location in the world with just three geographic coordinates: latitude, longitude and altitude. Now scientists at the Stanford University School of Medicine have discovered that specialized skin cells use a similar mapping system to identify where they belong in the body and how to act once they arrive.

These cellular cornerstones direct embryonic patterning and wound healing by sending vital location cues to their neighbors, and may help in growing tissue for transplant or understanding metastatic cancer.
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Sperm created in the laboratory from embryonic stem cells produce viable progeny

Scientists have demonstrated for the first time that embryonic stem (ES) cells cultured in the laboratory can produce sperm with the capacity to produce viable offspring. The research, published in the July issue of Developmental Cell, opens many exciting avenues for future studies, including investigation of mechanisms involved in sperm production and development of new treatment strategies for infertility.
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Medium is the message for stem cells in search of identities

Embryonic stem cells, prized for their astonishing ability to apparently transform into any kind of cell in the body, acquire their identities in part by interacting with their surroundings – even when they are outside of the body in a laboratory dish, University of Florida scientists report.

Using an animal model of embryonic stem cell development, researchers with UF’s McKnight Brain Institute have begun to answer one of the most fundamental questions in science – how does a batch of immature cells give rise to an organ as extraordinarily complex as the human brain?

The findings, to be published this week in the Proceedings of the National Academy of Sciences, may one day help scientists create laboratory environments to grow specialized cells that can be transplanted into patients to treat epilepsy, Parkinson’s, Huntington’s and Alzheimer’s diseases or other brain disorders.
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Growth factor triggers growth of new blood vessels in the heart

The newest concept for treating coronary artery disease is to induce hearts to grow their own new blood vessels to bypass damaged tissue or clogged arteries. Unfortunately, clinical trials of two important blood-vessel growth factors — fibroblast growth factor 2 (FGF2) and vascular endothelial growth factor (VEGF) — have not produced stellar results.

Now researchers at Washington University School of Medicine in St. Louis have investigated a third signaling molecule — called Sonic hedgehog — that could overcome problems associated with FGF2 and VEGF therapy.
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Discoveries may advance stem cell therapy for Parkinson’s, cancer patients

Two studies in the Jan. 27, 2006 issue of Cell have yielded evidence that could prove a boon for stem cell therapies aimed at patients with Parkinson’s disease and those with compromised immune systems due to intensive cancer therapy or autoimmune disease, according to researchers. The basic findings in mice revealed critical factors that determine the fate of one type of nerve cell progenitor and that set bone marrow stem cells into action.

Researchers at the Karolinska Institutet in Sweden discovered a “master determinant” that turns embryonic stem cells into bona fide dopamine neurons, brain cells that degenerate in those with Parkinson’s disease. The findings hold promise for the future of cell replacement therapy for the debilitating and incurable disease characterized by tremors, said study authors Thomas Perlmann and Johan Ericson. The results also underscore the general importance of a thorough understanding of development for producing authentic cells of a desired type from stem cells.
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Tiny RNA molecules fine-tune the brain’s synapses

Non-coding regions of the genome – those that don’t code for proteins – are now known to include important elements that regulate gene activity. Among those elements are microRNAs, tiny, recently discovered RNA molecules that suppress gene expression. Increasing evidence indicates a role for microRNAs in the developing nervous system, and researchers from Children’s Hospital Boston now demonstrate that one microRNA affects the development of synapses – the points of communication between brain cells that underlie learning and memory.

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Scientists show that cloned stem cells are identical to fertilized stem cells

Scientists generally agree that all cloned animals are biologically flawed. But they don’t agree about what that means for stem cells derived from cloned embryos, the basis for therapeutic cloning.

Also known as somatic cell nuclear transfer, therapeutic cloning is a promising approach to create individually customized cellular therapies for treating certain disorders. Demonstrated in mice but not in humans, it begins with stem cells derived from a cloned embryo. But if cloned embryos can’t produce normal organisms, how can they produce normal stem cells?

Analyzing the complete gene-expression profiles of both cloned and fertilization-derived stem cells in mice, scientists at Whitehead Institute for Biomedical Research now have concluded that the two are, in fact, indistinguishable.
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Hedgehog protein blocks fat production, produces more bone

A protein that guides the early development of creatures as diverse as fruit flies and humans also plays a role in regulating fat and bone formation in adult organisms, researchers at UT Southwestern Medical Center have discovered.

The findings, reported in the January issue of the journal Cell Metabolism, open an avenue for potential therapy in humans for obesity, diabetes, osteoporosis and lipodystrophy, a disorder characterized by a selective loss of body fat.
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Fish increase their lifespan by evolving a longer reproductive period

A UC Riverside-led research team has found that as some populations of an organism evolve a longer lifespan, they do so by increasing only that segment of the lifespan that contributes to “fitness” – the relative ability of an individual to contribute offspring to the next generation. Study results appear Dec. 27 in the online edition of the Public Library of Science – Biology.

The study supports the controversial hypothesis that natural selection – the process in nature by which only organisms best adapted to their environment tend to survive and pass on their genetic characters in increasing numbers to succeeding generations – introduces changes in only a specific segment of an organism’s lifespan.

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Researcher finds neuron growth in adult brain

Despite the prevailing belief that adult brain cells don’t grow, a researcher at MIT’s Picower Institute for Learning and Memory reports in the Dec. 27 issue of Public Library of Science (PLoS) Biology that structural remodeling of neurons does in fact occur in mature brains.

This finding means that it may one day be possible to grow new cells to replace ones damaged by disease or spinal cord injury, such as the one that paralyzed the late actor Christopher Reeve.

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Ancient Jawless Vertebrates Use Novel Immune System

Researchers recently discovered that the sea lamprey, a modern representative of ancient jawless vertebrates, fights invading pathogens by generating up to 100 trillion unique receptors. These receptors, referred to as VLRs, are proteins and function like antibodies and T-cell receptors, sentinels of the immune system in all jawed vertebrates, including humans.

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Scientists Discover a Gene That Regulates Lifespan

Genes that control the timing of organ formation during development also control timing of aging and death, and provide evidence of a biological timing mechanism for aging, Yale researchers report in the journal Science.

“Although there is a large variation in lifespan from species to species, there are genetic aspects to the processes of development and aging,” said Frank Slack, associate professor of Molecular, Cellular and Developmental Biology and senior author of the paper. “We used the simple, but genetically well-studied, C. elegans worm and found genes that are directly involved in determination of lifespan. Humans have genes that are nearly identical.”

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Researchers hone in on differentiation of heart stem cells

A team of scientists from the Gladstone Institute of Cardiovascular Disease (GICD) has identified a key factor in heart development that could help advance gene therapy for treating cardiac disorders.

The findings could help cardiac stem cell researchers one day develop strategies for gene and cell- mediated cardiac therapies.

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