While megakaryocytes are best known for producing platelets that heal wounds, these "mega" cells found in bone marrow also play a critical role in regulating stem cells according to new research from the Stowers Institute for Medical Research. The study is the first to show that hematopoietic stem cells (the parent cells) can be directly controlled by their own progeny (megakaryocytes).
Within our fat lives a variety of cells with the potential to become bone, cartilage or more fat...
The liver provides critical functions, such as...
Biochemists in California have developed a program that predicts the placement of chemical marks that control the activity of genes based on sequences of DNA. By comparing sequences with and without epigenomic modification, the researchers identified DNA patterns associated with the changes. They call this novel analysis pipeline Epigram and have made both the program and the DNA motifs they identified openly available to other scientists.
It’s one of the highest-profile cases of scientific fraud in memory: In 2005, South Korean researcher Woo-Suk Hwang and colleagues made international news by claiming that they had produced embryonic stem cells from a cloned human embryo using nuclear transfer. But within a year, the work had been debunked, soon followed by findings of fraud. South Korea put a moratorium on stem cell research funding.
The Japanese laboratory that retracted a paper reporting a potentially major breakthrough in stem cell research said Wednesday its researchers have not managed to replicate the results. Scientists at the government-affiliated RIKEN Center for Developmental Biology said they are still trying to match results reported in two papers published by Nature in January and then retracted in July.
Cytori Therapeutics said Tuesday it has halted trials of its experimental stem cell therapy for heart failure after three patients developed blood flow problems. The San Diego-based company said it placed the hold on two studies after the patients developed problems with blood flow to the brain. Two of the patients' symptoms resolved in a short period of time and a third was still recovering, the company said in a statement.
A new stem cell discovery might one day lead to a more streamlined process for obtaining stem cells, which in turn could be used in the development of replacement tissue for failing body parts, according to Univ. of California, San Francisco scientists who reported the findings in Cell.
In two papers published in January in the journal Nature, Japanese and American researchers said that they'd been able to transform ordinary mouse cells into versatile stem cells by exposing them to a mildly acidic environment. The scientists withdrew that claim Wednesday, admitting to "extensive" errors that meant they were “unable to say without a doubt" that the method works.
New research led by the Salk Institute shows, for the first time, that stem cells created using two different methods are far from identical. Their work reveals that stem cells created by moving genetic material from a skin cell into an empty egg cell, instead of activating genes to revert adult cells to their embryonic state, more closely resemble human embryonic stem cells, which are considered the gold standard in the field.
Mesenchymal stem cells have become attractive tools for bioengineers, but some scientists haven’t given up on their regenerative potential. A research team at Harvard Univ. recently found that transplanting mesenchymal stem cells along with blood vessel-forming cells naturally found in circulation improves results. This co-transplantation keeps the mesenchymal stem cells alive longer in mice after engraftment, up to weeks from just hours.
Researchers have developed new methods to trace the life history of individual cells back to their origins in the fertilized egg. By looking at the copy of the human genome present in healthy cells, and by looking at the numbers and types of mutations in a cell's DNA, biologists in the U.K. have been able to build a picture of each cell's development from the early embryo on its journey to become part of an adult organ.
New research suggests that scientists have only scratched the surface of understanding the nature, physiology and location of stem cells. Specifically, the report suggests that embryonic and induced pluripotent stem cells may not be the only source from which all three germ layers in the human body (nerves, liver or heart and blood vessels) can develop.
Scientists working to make gene therapy a reality have solved a major hurdle: how to bypass a blood stem cell’s natural defenses and efficiently insert disease-fighting genes into the cell’s genome. In a new study, a team of researchers report that the drug rapamycin, which is commonly used to slow cancer growth, enables delivery of a therapeutic dose of genes to blood stem cells while preserving stem cell function.
How does a stem cell decide what path to take? In a way, it’s up to the wisdom of the crowd. The DNA in a pluripotent stem cell is bombarded with waves of proteins whose ebb and flow nudge the cell toward becoming blood, bone, skin or organs. A new theory by scientists at Rice Univ. shows the cell’s journey is neither a simple step-by-step process nor all random.
When stem cells are used to regenerate bone tissue, many wind up migrating away from the repair site, which disrupts the healing process. But a technique employed by a Univ. of Rochester research team keeps the stem cells in place, resulting in faster and better tissue regeneration. The keyis encasing the stem cells in polymers that attract water and disappear when their work is done.
One of the biggest challenges for medical researchers studying the effectiveness of stem cell therapies is that transplants or grafts of cells are often rejected by the hosts. This rejection can render experiments useless. Now, researchers at the Univ. of Missouri have shown that a new line of genetically modified pigs will host transplanted cells without the risk of rejection.
The gap between stem cell research and regenerative medicine just became a lot narrower, thanks to a new technique that coaxes stem cells, with potential to become any tissue type, to take the first step to specialization. It is the first time this critical step has been demonstrated in a laboratory.
A Harvard Univ.-led team is the first to demonstrate the ability to use low-power light to trigger stem cells inside the body to regenerate tissue, an advance they reported in Science Translational Medicine. The research lays the foundation for a host of clinical applications in restorative dentistry and regenerative medicine more broadly, such as wound healing, bone regeneration and more.
Researchers in New York have been able to, for the first time, generate fully functional human cartilage from mesenchymal stem cells by mimicking, in vitro, the developmental process of mesenchymal condensation. While there has been great success in engineering pieces of cartilage using young animal cells, no one has, until now, been able to reproduce these results using adult human stem cells from bone marrow or fat.
In a potential step toward new diabetes treatments, scientists used a cloning technique to make insulin-producing cells with the DNA of a diabetic woman. The approach could someday aid treatment of the Type 1 form of the illness, which is usually diagnosed in childhood and accounts for about 5% of diabetes cases in the U.S.
A new study has discovered that stem cells in bone marrow need to produce hydrogen sulfide in order to properly multiply and form bone tissue. The presence of hydrogen sulfide produced by the cells governs the flow of calcium ions, which activates a chain of cellular signals that results in osteogenesis, or the creation of new bone tissue, and keeps the breakdown of old bone tissue at a proper level.
The Japanese scientist accused of falsifying data in a widely heralded stem-cell research paper said Wednesday the results are valid despite mistakes in their presentation. Haruko Obokata, 30, struggled to maintain her composure during a televised news conference packed with hundreds of reporters, but insisted she did not tamper with the data to fabricate results.
Researchers have reported they can generate human motor neurons from stem cells much more quickly and efficiently than previous methods allowed. The new method involves adding critical signaling molecules to precursor cells a few days earlier than previous methods specified. This increases the proportion of healthy motor neurons derived from stem cells (from 30 to 70%) and cuts in half the time required to do so.
Stem cells have the potential to repair human tissue and maintain organ function in chronic disease, but a major problem has been how to mass-produce such a complex living material. Scientists in the U.K. have now developed a new substance which could simplify the manufacture of therapeutic cells by allowing both self-renewal of cells and evolution into cardiomyocyte cells.
A new organ has been developed at George Washington Univ. to help return blood flow from veins lacking functional valves. A rhythmically contracting cuff made of cardiac muscle cells surrounds the vein acting as a 'mini heart' to aid blood flow through venous segments. The cuff can be made of a patient’s own adult stem cells, eliminating the chance of implant rejection.
In 2007, Massachusetts Institute of Technology scientists developed a type of microscopy that allowed them to detail the interior of a living cell in 3-D, without adding any fluorescent markers or other labels. This technique also revealed key properties, such as the cells’ density. Now the researchers have adapted that method so they can image cells as they flow through a tiny microfluidic channel.
Overcoming a major limitation to the study of the origins and progress of human disease, Yale Univ. researchers report that they have transplanted human innate immune cells into mouse models, which resulted in human immune responses. This study has reproduced human immune function at a level not seen previously, and could significantly improve the translation of knowledge gained from mouse studies into humans.
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