Antigravics

http://www.physorg.com/news175278162.html

>> Damaged knee joints might one day be repaired with cartilage grown from stem cells in a laboratory, based on research by Professor Kyriacos Athanasiou, chair of the UC Davis Department of Biomedical Engineering and his colleagues.

Using adult stem cells from bone marrow and skin as well as human embryonic stem cells, Athanasiou and his group have already grown cartilage tissue in the lab. Now they are experimenting with various chemical and mechanical stimuli to improve its properties.

Cartilage is one of the very rare tissues that lacks the ability to heal itself. When damaged by injury or osteoarthritis, the effects can be long-lasting and devastating.

"If I cut a tiny line on articular cartilage (the cartilage that covers the surfaces of bones at joints), it will never be erased",Athanasiou said. "It's like writing on the moon. If I go back to look at it a year later, it will look exactly the same".

Work that Athanasiou's group began in the early 1990s at Rice University has resulted in the only FDA-approved products for treatment of small lesions on articular cartilage. (In total, Athanaisou's patents have resulted in 15 FDA-approved products.)

"This will be live, biological cartilage that will not only fill defects, but will potentially be able to resurface the entire surface of joints that have been destroyed by osteoarthritis," Athanasiou said. Currently, joint replacements using metal and plastic prosthetics are the only recourse for the one in five adults who will suffer major joint damage from osteoarthritis. >>

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>>> The exceptional sensitivity of these neural stem cells suggests that we are going to have to rethink our understanding of stem cell susceptibility to radiation, including cosmic radiation encountered during space travel, as well as radiation doses that accompany different medical procedures.”

~ Dennis A. Steindler, Ph.D., executive director of UF’s McKnight Brain Institute

The research indicates the need to find a way to protect astronauts from this health risk before anyone heads out to Mars, or camps out on the moon at the proposed lunar base.

Using a mouse model designed to reveal even slight changes in brain cell populations, scientists found radiation appeared to target a particular type of stem cell in an area of the brain believed to be important for learning and mood control.

These findings from a team of researchers from the Cold Spring Harbor Laboratory, Brookhaven National
Laboratory, NASA’s Kennedy Space Center and the McKnight Brain Institute of the University of Florida,
suggest that identifying medications or physical shielding to protect astronauts from cosmic and solar radiation is necessary for the success of all human space missions beyond low Earth orbit.

Stem cells are especially important cells because they alone have the remarkable ability to renew themselves, and produce a vast variety of different cell types.

For the study, Cold Spring Harbor Laboratory scientists developed mice that were genetically engineered with easily identifiable, fluorescent stem cells. The stem cells lose their fluorescence when they transform into neurons, which makes it easier to account for them.

Next, scientists at the NASA Space Radiation Laboratory at the Brookhaven National Laboratory in Upton,
N.Y., administered a single dose of radiation to the mice about equal to the amount astronauts would receive after a three-year space voyage to Mars.

Unexpectedly, researchers found that a special type of stem cell is selectively killed in the hippocampus,
according to Grigori Enikolopov, Ph.D., a neurobiologist at Cold Spring Harbor Laboratory. The cell is
described as quiescent — or quiet — because even though it is the wellspring that repopulates the brain with new cells, it exists in relative repose while its daughter cells divide and reproduce in great numbers.

“Our findings are surprising because it is assumed that dividing cells are the most vulnerable to radiation — that is why radiation is used in cancer therapy,” Enikolopov said. “These stem cells divide quite rarely and it was unexpected that they would be the most vulnerable to this type of radiation. But at least two thirds of these quiescent cells died. The challenge now is to find something to protect those cells.”

What specific types of cells are at risk is vital information for scientists planning long lunar expeditions or deep space missions. The President’s Commission on Implementation of United States Space Exploration Policy outlined plans to send a human expedition to the moon by 2020. For this to become a reality, NASA must find a way to ensure the safety and health of the crew.

“Space radiation has not been a serious problem for NASA human missions because they have been short in duration or have occurred in low Earth orbit, within the protective magnetic field of the Earth,” said Philip Scarpa, M.D., a NASA flight surgeon at NASA’s Kennedy Space Center in Florida. “However, if we plan to leave low Earth orbit to go back to the moon for long durations or on to Mars, we need to better investigate this issue and assess the risk to the astronauts in order to know whether we need to develop countermeasures such as medications or improved shielding.”

The finding raises concerns about the cognitive and emotional risks associated with radiation exposure during human space exploration missions.

Philip Scarpa, M.D., a NASA flight surgeon at NASA’s Kennedy Space Center acknowledged, “We
currently know very little about the effects of space radiation, especially heavy element cosmic radiation, which is expected on future space missions and was the type of radiation used in this study. In addition, we should expect that within each critical organ system, there may be different cell sensitivities that need to be considered when defining space radiation dose limits.” >>>

http://www.physorg.com/news177704058.html

>> The largest national stem cell study for heart disease showed the first evidence that transplanting a potent form of adult stem cells into the heart muscle of subjects with severe angina results in less pain and an improved ability to walk. The transplant subjects also experienced fewer deaths than those who didn't receive stem cells.

In the 12-month Phase II, double-blind trial, subjects' own purified stem cells, called CD34+ cells, were injected into their hearts in an effort to spur the growth of small blood vessels that make up the microcirculation of the heart muscle. Researchers believe the loss of these blood vessels contributes to the pain of chronic, severe angina.

"This is the first study to show significant benefit in pain reduction and improved exercise capacity in this population with very advanced heart disease," said principal investigator Douglas Losordo, M.D., the Eileen M. Foell Professor of Heart Research at the Northwestern University Feinberg School of Medicine and a cardiologist and director of the program in cardiovascular regenerative medicine at Northwestern Memorial Hospital, the lead site of the study.

Losordo, also director of the Feinberg Cardiovascular Research Institute, said this study provides the first evidence that a person's own stem cells can be used as a treatment for their heart disease. He cautioned, however, that the findings of the 25-site trial with 167 subjects, require verification in a larger, Phase III study.

He presented his findings Nov. 17 at the American Heart Association Scientific Sessions 2009.

Out of the estimated 1 million people in the U.S. who suffer from chronic, severe angina -- chest pain due to blocked arteries -- about 300,000 cannot be helped by any traditional medical treatment such as angioplasty, bypass surgery or stents. This is called intractable or severe angina, the severity of which is designated by classes. The subjects in Losordo's study were class 3 or 4, meaning they had chest pain from normal to minimal activities, such as from brushing their teeth or even resting.

The stem cell transplant is the first therapy to produce an improvement in severe angina subjects' ability to walk on a treadmill. Twelve months after the procedure, the transplant subjects were able to double their improvement on a treadmill compared to the placebo group. It also took twice as long until they experienced angina pain on a treadmill compared to the placebo group, and, when they felt pain, it went away faster with rest. In addition, they had fewer overall episodes of chest pain in their daily lives.

In the trial, the CD34+ cells were injected into 10 locations in the heart muscle. A sophisticated electromechanical mapping technology identifies where the heart muscle is alive but not functioning, because it is not receiving enough blood supply. >>>

http://www.physorg.com/news178987799.html


A representation of relative size of a typical RNA molecule involved in transfer of genetic information and newly discovered RNA molecule GOLLD, the third largest and most complex RNA discovered to date. GOLLD appears to be used by viruses that infect bacteria.

>. Yale University researchers have found very large RNA structures within previously unstudied bacteria that appear crucial to basic biological functions such as helping viruses infect cells or allowing genes to "jump" to different parts of the chromosome.

These exceptionally large RNA molecules have been discovered using DNA sequence data available within the past few years. The findings, reported in the December 3 issue of the journal Nature, suggest many other unusual RNAs remain to be found as researchers explore the genes of more species of bacteria, said Ronald Breaker, senior author of the paper and professor of Molecular, Cellular and Developmental Biology.

"Our work reveals new classes of large RNAs exist, which would be akin to protein scientists finding new classes of enzymes," said Breaker, a Howard Hughes Medical Institute investigator. "Since we have only scratched the surface when it comes to examining microbial DNA that is covering the planet - there will certainly be many more large RNAs out there to discover and these newfound RNAs are also likely to have amazing functions as well."

The RNA molecules rank among the largest and most sophisticated RNAs yet discovered and may act like enzymes or carry out other complex functions in bacteria. The RNAs are found in bacteria which have yet to be grown in labs and so have been difficult to study.

RNA, or ribonucleic acid, is a chemical related to DNA. (Move definition up) RNA molecules are best known for carrying information from genes encoded in DNA to ribosomes, which are the protein-manufacturing machines of cells. However, some RNAs are not passive messengers, but form intricate structures that function like enzymes. For example, ribosomes are constructed using the two largest structured RNAs in bacteria that together function as the chemical factory for producing proteins. Yale University's Thomas Steitz won the 2009 Nobel Prize for his work to solve the atomic-resolution structure of ribosomes from bacterial cells. His work helped prove that ribosomes stitch together amino acids to make proteins using large RNAs like enzymes.

Nearly all of the largest structured RNAs previously known had been discovered in the 1970s or earlier. The scientists discovered these new RNAs by analyzing genetic data from poorly studied bacteria that in many cases cannot yet be grown in laboratory conditions. Only a tiny fraction of bacteria in the wild can now be grown in the lab, and scientists have only recently been able to collect genetic data from uncultivated bacteria. Consequently, there is a vast array of bacteria for which genetic data remains unavailable. Many other RNAs likely remain hidden in these under-studied bacteria that also have unusual characteristics that will greatly expand the known roles of RNA in biology.

The Breaker laboratory has used the explosion of DNA sequence information and new computer programs to discover six of the top twelve largest bacterial RNAs just in the last several years. One of the newly discovered RNAs, called GOLLD, is the third largest and most complex RNA discovered to date, and appears to be used by viruses that infect bacteria. Another large RNA revealed in the study, called HEARO, has a genetic structure that suggests it is part of a type of "jumping gene" that can move to new locations in the bacterial chromosome. They also found other RNAs in species of bacteria abundant in the open ocean, and some of these had been identified near Hawaii by researchers from the Massachusetts Institute of Technology. These RNAs are also very common in bacteria that live near the shore of the North American east coast, and so organisms that carry this RNA are likely to be very common in the waters of all the earth's oceans. >>>

http://www.physorg.com/news181224938.html

>> "The successful storage and implantation of stem cells poses significant challenges for tissue engineering in the nervous system, challenges in addition to those inherent to neural regeneration," said Dr. Ellis-Behnke, corresponding author. "There is a need for creating an environment that can regulate cell activity by delaying cell proliferation, proliferation and maturation. Nanoscaffolds can play a central role in organ regeneration as they act as templates and guides for cell proliferation, differentiation and tissue growth. It is also important to protect these fragile cells from the harsh environment in which they are transplanted."

According to Dr. Ellis-Behnke, advancements in nanotechnology offer a "new era" in tissue and organ reconstruction. Thus, finding the right nano-sized scaffold could be beneficial, so the research team developed a "self-assembling nanofiber scaffold" (SAPNS), a nanotechnology application to use for implanting young cells.

"Fine control of the nanodomain will allow for increased targeting of cell placement and therapeutic delivery amplified by cell encapsulation and implantation," explained Dr. Ellis-Behnke.

The research team created the scaffold to provide a substrate for cell adhesion and migration and to influence the survival of transplanted cells or the invasion of cells from surrounding tissue. The SAPNS they developed appear to slow the growth rate and differentiation of the cells, allowing the cells time to acclimate to their new environment.

"That delay is very important when the immune system tries attacking cells when they are placed in vivo," he further explained.

By manipulating both cell density and SAPNS concentration, the researchers were able to control the nanoenvironment surrounding PC 12 cells (a cell line developed from transplantable rat cells that respond to nerve growth factor), Schwann cells (glial cells that keep peripheral nerve fibers alive) and neural precursor cells (NPCs) and also control their proliferation, elongation, differentiation and maturation in vitro. They extended the method to living animals with implants in the brain and spinal cord.

The researchers concluded that the use of a combination of SAPNS and young cells eliminated the need for immuno-suppressants when cells were implanted in the central nervous system.

"Implanted stem cells are adversely susceptible to their new environment and quickly get old, but this study suggests a solution to conquer this problem," said Prof. Shinn-Zong Lin, professor of Neurosurgery at China University Medical Hospital, Taiwan and Chairman of the Pan Pacific Symposium on Stem Cell Research where part of this work was first presented. "The self-assembling nanofiber scaffold (SAPNS) provides a niche for the encapsulated stem cells by slowing down their growth, differentiation and proliferation, as well as potentially minimizing the immune response, thus enhancing the survival rate of the implanted stem cells. This allows the implanted stem cells to "stay forever young" and extend their neurites to reach distant targets, thereby re-establishing the neural circuits

This combination of stem cells and SAPNS technologies gives a new hope for building up younger neural circuit in the central neural system." >>>

http://www.physorg.com/news183817862.html


>> scientists at the Stanford University School of Medicine have succeeded in the ultimate switch: transforming mouse skin cells in a laboratory dish directly into functional nerve cells with the application of just three genes.

The cells make the change without first becoming a pluripotent type of stem cell -- a step long thought to be required for cells to acquire new identities.

The finding could revolutionize the future of human stem cell therapy and recast our understanding of how cells choose and maintain their specialties in the body.

"We actively and directly induced one cell type to become a completely different cell type," said Marius Wernig, MD, assistant professor of pathology and a member of Stanford's Institute for Stem Cell Biology and Regenerative Medicine. "These are fully functional neurons. They can do all the principal things that neurons in the brain do." That includes making connections with and signaling to other nerve cells — critical functions if the cells are eventually to be used as therapy for Parkinson's disease or other disorders.

Wernig is the senior author of the research, which will be published online Jan. 27 in Nature. Graduate student Thomas Vierbuchen is the lead author.

Although previous research has suggested that it's possible to coax specialized cells to exhibit some properties of other cell types, this is the first time that skin cells have been converted into fully functional neurons in a laboratory dish. The change happened within a week and with an efficiency of up to nearly 20 percent. The researchers are now working to duplicate the feat with human cells.

"This study is a huge leap forward," said Irving Weissman, MD, director of Stanford's Institute for Stem Cell Biology and Regenerative Medicine. "The direct reprogramming of these adult skin cells into brain cells that can show complex, appropriate behaviors like generating electrical currents and forming synapses establishes a new method to study normal and disordered brain cell function. Finally we may be able to capture and study conditions like Parkinson's or Alzheimer's or heritable mental diseases in the laboratory dish for the first time."

Until recently, it's been thought that cellular specialization, or differentiation, was a one-way path: pluripotent embryonic stem cells give rise to all the cell types in the body, but as the daughter cells become more specialized, they also become more biologically isolated. Like a tree trunk splitting first into branches and then into individual leaves, the cells were believed to be consigned to one developmental fate by physical modifications — called epigenetic changes — added to their DNA along the way. A skin cell could no more become a nerve cell than a single leaf could flit from branch to branch or Superman could become Clark Kent in midair.

That view began to change when Dolly the sheep was cloned from an adult cell in 1997, showing that, under certain conditions, a specialized cell could shed these restrictions and act like an embryonic stem cell.

And in 2007, researchers announced the creation of induced pluripotent stem cells, or iPS cells, from human skin cells by infecting them with four stem-cell-associated proteins called transcription factors. Once the cells had achieved a pluripotent state, the researchers coaxed them to develop into a new cell type. The process was often described in concept as moving the skin cells backward along the differentiation pathway (in the leaves analogy, reversing down the branch to the tree's trunk) and then guiding them forward again along a different branch into a new lineage.

Finally, in 2008, Doug Melton, PhD, a co-director of Harvard's Stem Cell Institute, showed it was possible in adult mice to reprogram one type of cell in the pancreas to become another pancreatic cell type by infecting them with a pool of viruses expressing just three transcription factors.

As a result, Wernig, who as a postdoctoral fellow in Rudolf Jaenisch's laboratory at the Whitehead Institute in Massachusetts participated in the initial development of iPS cells, began to wonder whether the pluripotent pit stop was truly necessary. Thomas Südhof, the Avram Goldstein Professor in the Stanford School of Medicine, also collaborated on the research.

To test the theory, Wernig, Vierbuchen and graduate student Austin Ostermeier amassed a panel of 19 genes involved in either epigenetic reprogramming or neural development and function. They used a virus called a lentivirus to infect skin cells from embryonic mice with the genes, and then monitored the cells' response. After 32 days they saw that some of the former skin cells now looked like neural cells and expressed neural proteins.

The researchers, which included postdoctoral scholar Zhiping Pang, PhD, used a mix-and-match approach to winnow the original pool of 19 genes down to just three. They also tested the procedure on skin cells from the tails of adult mice. They found that about 20 percent of the former skin cells transformed into neural cells in less than a week. That may not, at first, sound like a quick change, but it is vast improvement over iPS cells, which can take weeks. What's more, the iPS process is very inefficient: Usually only about 1 to 2 percent of the original cells become pluripotent.

In Wernig's experiments, the cells not only looked like neurons, they also expressed neural proteins and even formed functional synapses with other neurons in laboratory dish.

"We were very surprised by both the timing and the efficiency," said Wernig. "This is much more straightforward than going through iPS cells, and it's likely to be a very viable alternative." Quickly making neurons from a specific patient may allow researchers to study particular disease processes such as Parkinson's in a laboratory dish, or one day to even manufacture cells for therapy.

The research suggests that the pluripotent stage, rather than being a required touchstone for identity-shifting cells, may simply be another possible cellular state. Wernig speculates that finding the right combination of cell-fate-specific genes may trigger a domino effect in the recipient cell, wiping away restrictive DNA modifications and imprinting a new developmental fate on the genomic landscape.

"It may be hard to prove," said Wernig, "but I no longer think that the induction of iPS cells is a reversal of development. It's probably more of a direct conversion like what we're seeing here, from one cell type to another that just happens to be more embryonic-like. This tips our ideas about epigenetic regulation upside down."

Provided by Stanford University (news : web) >>.

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>> Northwestern University researchers are the first to design a bioactive nanomaterial that promotes the growth of new cartilage in vivo and without the use of expensive growth factors. Minimally invasive, the therapy activates the bone marrow stem cells and produces natural cartilage. No conventional therapy can do this.

The results will be published online the week of Feb. 1 by the Proceedings of the National Academy of Sciences (PNAS).

"Unlike bone, cartilage does not grow back, and therefore clinical strategies to regenerate this tissue are of great interest," said Samuel I. Stupp, senior author, Board of Trustees Professor of Chemistry, Materials Science and Engineering, and Medicine, and director of the Institute for BioNanotechnology in Medicine. Countless people -- amateur athletes, professional athletes and people whose joints have just worn out -- learn this all too well when they bring their bad knees, shoulders and elbows to an orthopaedic surgeon.

Damaged cartilage can lead to joint pain and loss of physical function and eventually to osteoarthritis, a disorder with an estimated economic impact approaching $65 billion in the United States. With an aging and increasingly active population, this figure is expected to grow.

"Cartilage does not regenerate in adults. Once you are fully grown you have all the cartilage you'll ever have," said first author Ramille N. Shah, assistant professor of materials science and engineering at the McCormick School of Engineering and Applied Science and assistant professor of orthopaedic surgery at the Feinberg School of Medicine. Shah is also a resident faculty member at the Institute for BioNanotechnology in Medicine.

Type II collagen is the major protein in articular cartilage, the smooth, white connective tissue that covers the ends of bones where they come together to form joints.

"Our material of nanoscopic fibers stimulates stem cells present in bone marrow to produce cartilage containing type II collagen and repair the damaged joint," Shah said. "A procedure called microfracture is the most common technique currently used by doctors, but it tends to produce a cartilage having predominantly type I collagen which is more like scar tissue."

The Northwestern gel is injected as a liquid to the area of the damaged joint, where it then self-assembles and forms a solid. This extracellular matrix, which mimics what cells usually see, binds by molecular design one of the most important growth factors for the repair and regeneration of cartilage. By keeping the growth factor concentrated and localized, the cartilage cells have the opportunity to regenerate.

Together with Nirav A. Shah, a sports medicine orthopaedic surgeon and former orthopaedic resident at Northwestern, the researchers implanted their nanofiber gel in an animal model with cartilage defects.

The animals were treated with microfracture, where tiny holes are made in the bone beneath the damaged cartilage to create a new blood supply to stimulate the growth of new cartilage. The researchers tested various combinations: microfracture alone; microfracture and the nanofiber gel with growth factor added; and microfracture and the nanofiber gel without growth factor added.

They found their technique produced much better results than the microfracture procedure alone and, more importantly, found that addition of the expensive growth factor was not required to get the best results. Instead, because of the molecular design of the gel material, growth factor already present in the body is enough to regenerate cartilage.

The matrix only needed to be present for a month to produce cartilage growth. The matrix, based on self-assembling molecules known as peptide amphiphiles, biodegrades into nutrients and is replaced by natural cartilage.

More information: The PNAS paper is titled "Supramolecular Design of Self-assembling Nanofibers for Cartilage Regeneration." In addition to Stupp, Ramille Shah and Nirav Shah, other authors of the paper are Marc M. Del Rosario Lim, Caleb Hsieh and Gordon Nuber, all from Northwestern. >>>>

http://www.physorg.com/news184769748.html

>> Tiny circles of DNA are the key to a new and easier way to transform stem cells from human fat into induced pluripotent stem cells for use in regenerative medicine, say scientists at the Stanford University School of Medicine. Unlike other commonly used techniques, the method, which is based on standard molecular biology practices, does not use viruses to introduce genes into the cells or permanently alter a cell's genome.

It is the first example of reprogramming adult cells to pluripotency in this manner, and is hailed by the researchers as a major step toward the use of such cells in humans. They hope that the ease of the technique and its relative safety will smooth its way through the necessary FDA approval process.

"This technique is not only safer, it's relatively simple," said Stanford surgery professor Michael Longaker, MD, and co-author of the paper. "It will be a relatively straightforward process for labs around the world to begin using this technique.

We are moving toward clinically applicable regenerative medicine."

The Stanford researchers used the so-called minicircles - rings of DNA about one-half the size of those usually used to reprogram cell - to induce pluripotency in stem cells from human fat. Pluripotent cells can then be induced to become many different specialized cell types. Although the researchers plan to first use these cells to better understand - and perhaps one day treat-human heart disease, induced pluripotent stem cells, or iPS cells, are a starting point for research on many human diseases.

"Imagine doing a fat or skin biopsy from a member of a family with heart problems, reprogramming the cells to pluripotency and then making cardiac cells to study in a laboratory dish," said cardiologist Joseph Wu, MD, PhD. "This would be much easier and less invasive than taking cell samples from a patient's heart." Wu is the senior author of the research, which will be published online Feb. 7 in Nature Methods. Research assistant Fangjun Jia, PhD is the lead author of the work.

Longaker is the deputy director of Stanford's Institute for Stem Cell Biology and Regenerative Medicine and director of children's surgical research at Lucile Packard Children's Hospital. Wu is an assistant professor of cardiology and of radiology, and a member of Stanford's Cardiovascular Institute. A third author, Mark Kay, MD, PhD, is the Dennis Farrey Family Professor in Pediatrics and professor of genetics.

The finding brings together disparate areas of Stanford research. Kay's laboratory invented the minicircles several years ago in a quest to develop suitable gene therapy techniques. At the same time, Longaker was discovering the unusual prevalence and developmental flexibility of stem cells from human fat. Meanwhile, Wu was searching for ways to create patient-specific cell lines to study some of the common, yet devastating, heart problems he was seeing in the clinic.

"About three years ago Mark gave a talk and I asked him if we could use minicircles for cardiac gene therapy," said Wu. "And then it clicked for me, that we should also be able to use them for non-viral reprogramming of adult cells."

The minicircle reprogramming vector works so well because it is made of only the four genes needed to reprogram the cells (plus a gene for a green fluorescent protein to track minicircle-containing cells). Unlike the larger, more commonly used DNA circles called plasmids, the minicircles contain no bacterial DNA, meaning that the cells containing the minicircles are less likely than plasmids to be perceived as foreign by the body. The expression of minicircle genes is also more robust, and the smaller size of the minicircles allows them to enter the cells more easily than the larger plasmids. Finally, because they don't replicate they are naturally lost as the cells divide, rather than hanging around to potentially muck up any subsequent therapeutic applications.

The researchers chose to test the reprogramming efficiency of the minicircles in stem cells from human fat because previous work in Wu and Longaker's lab has shown that the cells are numerous, easy to isolate and amenable to the iPS transformation, probably because of the naturally higher levels of expression of some reprogramming genes. They found that about 10.8 percent of the stem cells took up the minicircles and expressed the green fluorescent protein, or GFP, versus about 2.7 percent of cells treated with a more traditional DNA plasmid.

When the researchers isolated the GFP-expressing cells and grew them in a laboratory dish, they found that the minicircles were gradually lost over a period of four weeks. To be sure the cells got a good dose of the genes, they reapplied the minicircles at days four and six. After 14 to 16 days, they began to observe clusters of cells resembling embryonic stem cell colonies - some of which no longer expressed GFP.

They isolated these GFP-free clusters and found that they exhibited all of the hallmarks of induced pluripotent cells: they expressed embryonic stem cell genes, they had similar patterns of DNA methylation, they could become multiple types of cells and they could form tumors called teratomas when injected under the skin of laboratory mice. They also confirmed that the minicircles had truly been lost and had not integrated into the stem cells' DNA.

Altogether, the researchers were able to make 22 new iPS cell lines from adult human adipose stem cells and adult human fibroblasts. Although the overall reprogramming efficiency of the minicircle method is lower than that of methods using viral vectors to introduce the genes (about 0.005 percent vs. about 0.01-0.05 percent, respectively), it still surpasses that of using conventional bacterial-based plasmids. Furthermore, stem cells from fat, and, for that matter, fat itself, are so prevalent that a slight reduction in efficiency should be easily overcome.

"This is a great example of collaboration," said Longaker. "This discovery represents research from four different departments: pediatrics, surgery, cardiology and radiology. We were all doing our own things, and it wasn't until we focused on cross-applications of our research that we realized the potential."

"We knew minicircles worked better than plasmids for gene therapy," agreed Kay, "but it wasn't until I started talking to stem cell people like Joe and Mike that we started thinking of using minicircles for this purpose. Now it's kind of like 'why didn't we think of this sooner?'" >>>

http://www.physorg.com/news186758255.html

>> Schwartz devised a method for turning ordinary human skin cells into heart cells. The cells developed are similar to embryonic stem cells and ultimately can be made into early-stage heart cells derived from a patient's own skin. These then could be implanted and grown into fully developed beating heart cells, reversing the damage caused by previous heart attacks. These new cells would replace the damaged cardiac tissue that weakens the heart's ability to pump, develops into scar tissue and causes arrhythmias. Early clinical trials using these reprogrammed cells on actual heart patients could begin within one or two years.

Although Schwartz is not the first scientist to turn adult cells into such stem cells, his improved method could pave the way for breakthroughs in other diseases. Schwartz's method requires fewer steps and yields more stem cells. Armed with an effective way to make induced stem cells from a patient's own skin, scientists can then begin the work of growing all kinds of human cells.

For example, new brain cells could treat Alzheimer's patients or those with severe brain trauma, or a diabetic could get new insulin-producing cells in the pancreas. Generating new kidney, lung or liver tissue is also possible, with scientists even being able to one day grow an entirely new heart or other organ from these reprogrammed cells. Additionally, Schwartz and his team are working on turning induced stem cells into skeletal muscle cells to treat muscular dystrophy. >>>

>> UCSF scientists report that they were able to prompt a new period of "plasticity," or capacity for change, in the neural circuitry of the visual cortex of juvenile mice. The approach, they say, might some day be used to create new periods of plasticity in the human brain that would allow for the repair of neural circuits following injury or disease.

The strategy - which involved transplanting a specific type of immature neuron from embryonic mice into the visual cortex of young mice - could be used to treat neural circuits disrupted in abnormal fetal or postnatal development, stroke, traumatic brain injury, psychiatric illness and aging.

Like all regions of the brain, the visual cortex undergoes a highly plastic period during early life. Cells respond strongly to visual signals, which they relay in a rapid, directed way from one appropriate cell to the next in a process known as synaptic transmission. The chemical connections created in this process produce neural circuitry that is crucial for the function of the visual system. In mice, this critical period of plasticity occurs around the end of the fourth week of life.

The catalyst for the so-called critical period plasticity in the visual cortex is the development of synaptic signaling by neurons that release the inhibitory neurotransmitter GABA. These neurons receive excitatory signals from other neurons, thus helping to maintain the balance of excitation and inhibition in the visual system.

In their study, published in the journal Science, (Vol. 327. no. 5969, 2010), the scientists wanted to see if the embryonic neurons, once they had matured into GABA-producing inhibitory neurons, could induce plasticity in mice after the normal critical period had closed.

The team first dissected the immature neurons from their origin in the embryonic medial ganglionic eminence (MGE) of the embryonic mice. Then they transplanted the MGE cells into the animals' visual cortex at two different juvenile stages. The cells, targeted to the visual cortex, dispersed through the region, matured into GABAergic inhibitory neurons, and made widespread synaptic connections with excitatory neurons.

The scientists then carried out a process known as monocular visual deprivation, in which they blocked the visual signals to one eye in each of the animals for four days. When this process is carried out during the critical period, cells in the visual cortex quickly become less responsive to the eye deprived of sensory input, and become more responsive to the non-deprived eye, creating alterations in the neural circuitry. This phenomenon, known as ocular dominance plasticity, greatly diminishes as the brain matures past this critical postnatal developmental period.

The team wanted to see if the transplanted cells would affect the visual system's response to the visual deprivation after the critical period. They studied the cells' effects after allowing them to mature for varying lengths of time. When the cells were as young as 17 days old or as old as 43 days old, they had little impact on the neural circuitry of the region. However, when they were 33-39 days old, their impact was significant. During that time, monocular visual deprivation shifted the neural responses away from the deprived eye and toward the non-deprived eye, revealing the state of ocular dominance plasticity.

Naturally occurring, or endogenous, inhibitory neurons are also around 33-39 days old when the normal critical period for plasticity occurs. Thus, the transplanted cells' impact occurred once they had reached the cellular age of inhibitory neurons during the normal critical period.

The finding, the team says, suggests that the normal critical period of plasticity in the visual cortex is regulated by a developmental program intrinsic to inhibitory neurons, and that embryonic inhibitory neuron precursors can retain and execute this program when transplanted into the postnatal cortex, thereby creating a new period of plasticity.

"The findings suggest it ultimately might be possible to use inhibitory neuron transplantation, or some factor that is produced by inhibitory neurons, to create a new period of plasticity of limited duration for repairing damaged brains," says author Sunil P. Gandhi, PhD, a postdoctoral fellow in the lab of Michael Stryker, PhD, professor of physiology and a member of the Keck Center for Integrative Neurosciences at UCSF. "It will be important to determine whether transplantation is equally effective in older animals."

Likewise, "the results raise a fundamental question: how do these cells, as they pass through a specific stage in their development, create these windows of plasticity?" says author Derek G. Southwell, PhD, a student in the lab of Arturo Alvarez-Buylla, PhD, Heather and Melanie Muss Professor of Neurological Surgery and a member of the Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research at UCSF.

The findings could be relevant to understanding why learning certain behaviors, such as language, occurs with ease in young children but not in adults, says Alvarez-Buylla. "Grafted MGE cells may some day provide a way to induce cortical plasticity and learning later in life."

The findings also complement two other recent UCSF studies using MGE cells to modify neural circuits. In a collaborative study among the laboratories of Scott Baraban, PhD, professor of neurological surgery; John Rubenstein, MD, PhD, professor of psychiatry, and Alvarez-Buylla, the cells were grafted into the neocortex of juvenile rodents, where they reduced the intensity and frequency of epileptic seizures. (Proceedings of the National Academy of Science, vol. 106, no. 36, 2009). Other teams are exploring this tactic, as well.

http://www.physorg.com/news188745701.html

>> "Scientists have been puzzled by why human embryonic stem cells die at a critical step in the culture process. In addition to posing a question in fundamental biology, this created a huge technical challenge in the lab."

In the study, the team discovered two novel synthetic small molecule drugs that can be added to human stem cell culture that each individually prevent the death of these cells. The team also unravels the mechanisms by which the compounds promote stem cell survival, shedding light on a previously unknown aspect of stem cell biology.

The hope of most researchers in the field is that one day it will be possible to use stem cells — which possess the ability to develop into many other distinct cell types, such as nerve, heart, or lung cells — to repair damaged tissue from any number of diseases, from Type 1 diabetes to Parkinson's disease, as well as from injuries.

Laboratory work with human embryonic stem cells, however, has been hampered by their notorious fragility. In the process of growing stem cells in culture, scientists must split off cells from their cell colonies. At this point in the process, however, human embryonic stem cells die unless the scientists take extraordinary care that this does not happen.

"The current techniques to keep these cells alive are tedious and labor-intensive," said Ding. "Keeping the cells alive is so difficult that some people are discouraged from entering the field. It is very frustrating experience for everyone."

Mysteriously, mouse embryonic stem cells—which share much basic biology with human embryonic stem cells—do not pose the same difficulties in the laboratory. They can usually be split off from a colony and go on to survive and thrive.

To address these issues, the scientists decided to start with a screen of a library of chemical compounds to see if they could find any small molecules that could be added to the human embryonic stem cell culture that would promote the cells' survival.

When the scientists examined their results, they were elated to find two novel compounds (named Thiazovivin and Pyrintegrin) that both worked to dramatically protect the cells, promoting human embryonic stem cell survival by more than 30 fold.

"Basically, this solved this cell survival problem that has been plaguing scientists for more than 10 years," said Ding.

Next, using the two new survival-promoting small molecules as clues, the scientists set out to understand the biological mechanism behind the cells' survival or demise. By examining cell growth in the presence and absence of the compounds, the team found that the key factor was a protein on the cell surface called e-cadherin, which mediates interactions among cells and between cells and the extracellular matrix (a structure present between a variety of animal cells that provides support and anchorage for cells and regulates intercellular communication).

"While in the past people have often talked about the proteins in cell nucleus as regulating stem cell function, our study puts the focus on a different area," said Ding. "E-cadherin is a protein on the cell surface that is very important to cell survival and cell growth."

The team found that when human embryonic stem cells are cut out from the colony, this key protein is disrupted and then internalized within the cell. Without e-cadherin on the cell surface, cell signaling between the cells and their environment is disrupted and the cells quickly die.

Both chemical compounds identified by the study, however, protected e-cadherin from damage.

In further experiments, the scientists found that the key difference between human and mouse embryonic stem cells lay not only within the cells themselves, but also in and controlled by their microenvironment—the surrounding cells, signaling factors, and extracellular matrix. The scientists were able to transfer human embryonic stem cells into a mouse embryonic stem cell microenvironment. There, the scientists found, human cells were more likely to survive, even without the survival-promoting compounds.

Moreover, when the scientists chemically induced human embryonic stem cells back to an earlier stage of development—which had an extracellular environment similar to mouse embryonic stem cells conventionally used in the laboratory—there were also no longer problems growing them in culture.

"This validated our mechanistic investigations from a different angle," said Ding, "showing that we had dissected out a very core regulatory mechanism."

Ding expects that the methods discussed in the new study will soon be widely adopted by stem cell laboratories around the world.

"My lab currently uses the novel small molecules indentified in this study on a routine basis, making our life significantly easier and advancing our efforts," said Ding. "Even more, chemically inducing human embryonic stem cells back to an earlier stage of development has advantages for some areas of investigation."

http://www.physorg.com/news190309887.html

>> For the first time, human embryonic stem cells have been cultured under chemically controlled conditions without the use of animal substances, which is essential for future clinical uses. The method has been developed by researchers at Karolinska Institutet and is presented in the journal Nature Biotechnology.

Embryonic stem cells can be turned into any other type of cell in the body and have potential uses in treatments where sick cells need to be replaced. One problem, however, is that it is difficult to culture and develop human embryonic stem cells without simultaneously contaminating them. They are currently cultured with the help of proteins from animals, which rules out subsequent use in the treatment of humans. Alternatively the stem cells can be cultured on other human cells, known as feeder cells, but these release thousands of uncontrolled proteins and therefore lead to unreliable research results.

A research team at Karolinska Institutet (Sweden) has now managed to produce human stem cells entirely without the use of other cells or substances from animals. Instead they are cultured on a matrix of a single human protein: laminin-511.

"Now, for the first time, we can produce large quantities of human embryonic stem cells in an environment that is completely chemically defined," says professor Karl Tryggvason, who led the study. "This opens up new opportunities for developing different types of cell which can then be tested for the treatment of disease."

Together with researchers at the Harvard Stem Cell Institute, the researchers have also shown that in the same way they can culture what are known as reprogrammed stem cells, which have been converted back from tissue cells to stem cells.

Laminin-511 is part of our connective tissue and acts in the body as a matrix to which cells can attach. In the newly formed embryo, the protein is also needed to keep stem cells as stem cells. Once the embryo begins to develop different types of tissue, other types of laminin are needed.

Until now, different types of laminin have not been available to researchers, because they are almost impossible to extract from tissues and difficult to produce. Over the last couple of decades, Karl Tryggvason's research group has cloned the genes for most human laminins, studied their biological role, described two genetic laminin diseases and, in recent years, even managed to produce several types of laminin using gene technology. In this latest experiment, the researchers produced the laminin-511 using recombinant techniques.

http://www.physorg.com/news194526873.html

>> (AP) -- Dozens of people who were blinded or otherwise suffered severe eye damage when they were splashed with caustic chemicals had their sight restored with transplants of their own stem cells - a stunning success for the burgeoning cell-therapy field, Italian researchers reported Wednesday.

The treatment worked completely in 82 of 107 eyes and partially in 14 others, with benefits lasting up to a decade so far. One man whose eyes were severely damaged more than 60 years ago now has near-normal vision.

"This is a roaring success," said ophthalmologist Dr. Ivan Schwab of the University of California, Davis, who had no role in the study - the longest and largest of its kind.

Stem cell transplants offer hope to the thousands of people worldwide every year who suffer chemical burns on their corneas from heavy-duty cleansers or other substances at work or at home.

The approach would not help people with damage to the optic nerve or macular degeneration, which involves the retina. Nor would it work in people who are completely blind in both eyes, because doctors need at least some healthy tissue that they can transplant.

In the study, published online by the New England Journal of Medicine, researchers took a small number of stem cells from a patient's healthy eye, multiplied them in the lab and placed them into the burned eye, where they were able to grow new corneal tissue to replace what had been damaged. Since the stem cells are from their own bodies, the patients do not need to take anti-rejection drugs.

Adult stem cells have been used for decades to cure blood cancers such as leukemia and diseases like sickle cell anemia. But fixing a problem like damaged eyes is a relatively new use. Researchers have been studying cell therapy for a host of other diseases, including diabetes and heart failure, with limited success.

Adult stem cells, which are found around the body, are different from embryonic stem cells, which come from human embryos and have stirred ethical concerns because removing the cells requires destroying the embryos.

Currently, people with eye burns can get an artificial cornea, a procedure that carries such complications as infection and glaucoma, or they can receive a transplant using stem cells from a cadaver, but that requires taking drugs to prevent rejection.

The Italian study involved 106 patients treated between 1998 and 2007. Most had extensive damage in one eye, and some had such limited vision that they could only sense light, count fingers or perceive hand motions. Many had been blind for years and had had unsuccessful operations to restore their vision.

The cells were taken from the limbus, the rim around the cornea, the clear window that covers the colored part of the eye. In a normal eye, stem cells in the limbus are like factories, churning out new cells to replace dead corneal cells. When an injury kills off the stem cells, scar tissue forms over the cornea, clouding vision and causing blindness.

In the Italian study, the doctors removed scar tissue over the cornea and glued the laboratory-grown stem cells over the injured eye. In cases where both eyes were damaged by burns, cells were taken from an unaffected part of the limbus.

Researchers followed the patients for an average of three years and some as long as a decade. More than three-quarters regained sight after the transplant. An additional 13 percent were considered a partial success. Though their vision improved, they still had some cloudiness in the cornea.

Patients with superficial damage were able to see within one to two months. Those with more extensive injuries took several months longer.
"They were incredibly happy. Some said it was a miracle," said one of the study leaders, Graziella Pellegrini of the University of Modena's Center for Regenerative Medicine in Italy. "It was not a miracle. It was simply a technique."

Researchers in the United States have been testing a different way to use self-supplied stem cells, but that work is preliminary.

One of the successful transplants in the Italian study involved a man who had severe damage in both eyes as a result of a chemical burn in 1948. Doctors grafted stem cells from a small section of his left eye to both eyes. His vision is now close to normal.

In 2008, there were 2,850 work-related chemical burns to the eyes in the United States, according to the Bureau of Labor Statistics.
Schwab of UC Davis said stem cell transplants would not help those blinded by burns in both eyes because doctors need stem cells to do the procedure.
"I don't want to give the false hope that this will answer their prayers," he said.

Dr. Sophie Deng, a cornea expert at the UCLA's Jules Stein Eye Institute, said the biggest advantage was that the Italian doctors were able to expand the number of stem cells in the lab. This technique is less invasive than taking a large tissue sample from the eye and lowers the chance of an eye injury.

"The key is whether you can find a good stem cell population and expand it," she said.

http://www.physorg.com/news196533786.html

>> One of the characteristics of embryonic stem cells is their ability to form unusual tumors called teratomas. These tumors, which contain a mixture of cells from a variety of tissues and organs of the body, are typically benign. But they present a major obstacle to the development of human embryonic stem cell therapies that seek to treat a variety of human ailments such as Parkinson's, diabetes, genetic blood disorders and spinal cord injuries.

Now a team of biologists at UC San Diego funded by a grant from the California Institute for Regenerative Medicine, the state's stem-cell funding agency, has discovered a way to limit the formation of teratomas.

In this week's issue of the Proceedings of the National Academy of Sciences, the researchers report that they have identified a new signaling pathway critical for unlimited self propagation of embryonic stem cells. Using small molecule compounds that inhibit this pathway, the scientists were able to dramatically reduce the potential of embryonic stem cells to form teratomas.

"Human stem cell therapy involves differentiating human embryonic stem cells into the kinds of cells needed for the treatment," said Yang Xu, a professor of biology who headed the team that published the report. "But this differentiation is never complete, meaning that the final product is a mixture of cells inevitably containing undifferentiated embryonic stem cells. So by transplanting these cells into a patient, there's clearly a risk of producing teratomas."

If researchers could halt the propagation of human embryonic stem cells during lineage-specific differentiation before they are transplanted, they could avoid the risk of producing teratomas.

"This is a proof of concept to show how we can avoid teratomas in human embryonic stem cell therapies by studying the basic biology of these cells," said Xu. "At this point, we only see a significant but partial effect because we are targeting only one pathway. Once we identify more pathways required for teratoma formation by embryonic stem cells, we might be able to completely suppress the formation of teratomas by targeting multiple pathways simultaneously."

http://www.physorg.com/news197805027.html

>> Researchers at the Stanford University School of Medicine have developed a technique they believe will help scientists overcome a major hurdle to the use of adult stem cells for treating muscular dystrophy and other muscle-wasting disorders that accompany aging or disease: They've found that growing muscle stem cells on a specially developed synthetic matrix that mimics the elasticity of real muscle allows them to maintain their self-renewing properties.

"Cells don't normally exist in contact with a rigid cell culture dish," said Helen Blau, PhD, the Donald E. and Delia B. Baxter Professor and member of Stanford's Institute for Stem Cell Biology and Regenerative Medicine. "They sit on soft tissue. By mimicking this environment we can really influence their function and allow them to self-renew in ways we've never been able to achieve before."

Adult stem cells already exist in the body, and are important in regenerating tissues like blood, muscles and neurons in the brain. But scientists have struggled to produce them in quantities needed for therapies because the cells differentiate and lose their "stemness" as soon as they're placed in a tissue culture dish. This new method of growing the cells creates a way to study the behavior of many types of adult stem cells in culture and may revolutionize the ability to produce these cells for future therapies, say the researchers.

Blau is the senior author of the research, which will be published online July 15 in Science Express. Postdoctoral scholar Penney Gilbert, PhD, and graduate student Karen Havenstrite share first authorship of the work.

Self-renewal, or the ability to become both another stem cell and a differentiating daughter cell, is a defining trait of stem cells. This ability is necessary for a small number of cells to, for example, fully reconstitute the pantheon of blood cell types necessary to regenerate a patient's immune system after chemotherapy or to successfully contribute to the long-term generation of new, healthy muscle tissue. Until now, however, all attempts to grow these and some other adult stem cells, like blood stem cells, in culture have resulted in the cells differentiating into more specialized — but less therapeutically useful — progenitor cells. This differentiation constitutes a major obstacle to treating muscle-wasting diseases, for using cord blood or for treating blood cancers.

The researchers wondered if the way the cells are normally grown in culture could be the problem. After all, as Blau pointed out, cells are used to rubbing shoulders comfortably with their neighbors on all sides rather than being splayed out and anchored on a rigid plastic culture dish that is 100,000-fold less elastic than true muscle.

To find out if the cells would be happier on a softer, more giving surface, they had to develop an entirely new culture system. They turned to a material called hydrogel, which is made up of a latticework of polyethylene glycol polymers filled with water. Decreasing the percentage of polymer molecules in the mix makes the resulting matrix more elastic and wobbly; increasing it makes it more dense and rigid.

Hydrogel is often used as scaffolding to grow cells in two- and three-dimensional arrays useful in tissue engineering. But because it can swell over time, it was not possible to accurately calibrate the amount of proteins and other components needed to maintain the cells in this type of experiment. Gilbert and Havenstrite tinkered with the system until they came up with a version that maintains a constant volume, making it possible to test the effects of gels of different elasticity that all contained the same amount of protein. They then patterned the gel into hundreds of tiny wells and added one freshly isolated muscle stem cell per well.

After letting the cells grow for one week, the researchers found that the softer, or more pliant, gels mimicking the elasticity of muscle tissue had many more cells than the less-elastic gels. Closer investigation using an algorithm they developed for automated cell tracking showed that it wasn't because the cells were dividing more quickly, but because not as many were dying during the culture period. The computer program, which they have called the Baxter Algorithm to honor the Baxter Foundation that funded this portion of the work, reduced the time needed to analyze the cell division data by more than 90 percent.

"This in itself is a huge advance," Blau said of the software. "Until now it's been pretty impossible to do these studies without spending half a year or more manually scoring pictures or movies of cells in culture. Now we can figure out exactly how the cells divide and move, who begets who. As a result we can begin to study all types of variables."

After studying the dynamics of the muscle stem cells' division and dying, the researchers began to study specific aspects of their biology. They found that the cells grown on the softer surface were less likely than those grown on the harder surfaces to express a gene associated with differentiation called myogenin. They were also as able as freshly isolated muscle stem cells to contribute to the development of leg muscles when transplanted into recipient mice.

"Testing their function in animals like this is extremely important," said Blau. "It's really the only way to confirm their 'stemness.'"

To prove definitively that the stem cells were self-renewing, Gilbert and Blau turned to a "doublet" experiment. In this test, Gilbert allowed just one cell to divide just one time, resulting in two daughter cells. There are three potential combinations for these resulting doublets: two stem cells, one stem cell and one progenitor cell, or two progenitor cells. The first two represent self-renewal; the last does not. (A progenitor cell is one that can go on to differentiate into more specialized cells.)

Gilbert found that one-third of cells grown on the muscle-mimicking substrate expressed a muscle-stem-cell-specific gene (indicating that at least one of the two cells was a stem cell) but that only 6 percent of those grown on the plastic surface did so. Furthermore, when Gilbert transplanted five doublets (for a total of 10 cells) into mice from the muscle-mimicking substrate, the cells made themselves at home and began to contribute to muscle fiber development in three of 12 recipient animals. When she repeated the experiment with doublets grown on hard surfaces, none of the animals demonstrated similar engraftment.

"Clearly the cells grown on the more-elastic surfaces have better survival and self-renewing properties than those grown on standard tissue culture dishes," said Blau. "We conducted our experiments with muscle stem cells, but I expect this will be true for other types of adult stem cells as well."

In addition to exploring this possibility in the future, the researchers will also investigate how their findings may help advance therapies for conditions like muscular dystrophy. "Researchers really had no way to grow these cells in the laboratory before," said Blau. "These findings may allow us one day to replenish the muscles of patients with muscular dystrophy and other muscle-wasting diseases with healthy stem cells."

http://www.physorg.com/news198403107.html