New study into bladder regeneration heralds organ replacement treatment

Researchers in the United States have developed a medical model for regenerating bladders using stem cells harvested from a patient’s own bone marrow. The research, published in STEM CELLS, is especially relevant for paediatric patients suffering from abnormally developed bladders, but also represents another step towards new organ replacement therapies.

The research, led by Dr Arun Sharma and Earl Cheng from the Feinberg School of Medicine at Northwestern University and Children’s Memorial Research Center, focused on bone marrow mesenchymal stem cells (MSCs) taken from the patient. Previously studies into the regenerative capacity of cells in bladders have focused on animal models, but these have translated poorly in clinical settings.

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Researchers successfully reprogram keratinocytes attached to a single hair

The first reports of the successful reprogramming of adult human cells back into so-called induced pluripotent stem (iPS) cells, which by all appearances looked and acted liked embryonic stem cells created a media stir. But the process was woefully inefficient: Only one out of 10,000 cells could be persuaded to turn back the clock.

Now, a team of researchers led by Juan Carlos Izpisúa Belmonte at the Salk Institute for Biological Studies, succeeded in boosting the reprogramming efficiency more than 100fold, while cutting the time it takes in half. In fact, they repeatedly generated iPS cells from the tiny number of keratinocytes attached to a single hair plucked from a human scalp.

Scientists eliminate viral vector in stem cell reprogramming

Previously, Dr. Shinya Yamanaka of Kyoto University and the Gladstone Institute of Cardiovascular Disease, had shown that adult cells can be reprogrammed to become embryonic stem cell–like using a cancer-causing oncogene as one of the four genes required to reprogram the cells, and a virus to transfer the genes into the cells. In the last year, Dr. Yamanaka and other labs showed that the oncogene, c-Myc, is not needed. However the use of viruses that integrate into the genome prohibit use of iPS cells for regenerative medicine because of safety concerns: its integration into the cell’s genome might activate or inactivate critical host genes.

Now Dr. Yamanaka’s laboratory in Kyoto has eliminated the need for the virus. In a report published this week in Science, they showed that the critical genes can be effectively introduced without using a virus. The ability to reprogram adult cells into iPS cells without viral integration into the genome also lays to rest concerns that the reprogramming event might be dependent upon viral integration into specific genomic loci that could mediate the genetic switch.

Study unlocks stem cell DNA secrets

In a groundbreaking study led by an eminent molecular biologist at Florida State University, researchers have discovered that as embryonic stem cells turn into different cell types, there are dramatic corresponding changes to the order in which DNA is replicated and reorganized.

The findings bridge a critical knowledge gap for stem cell biologists, enabling them to better understand the enormously complex process by which DNA is repackaged during differentiation — when embryonic stem cells, jacks of all cellular trades, lose their anything-goes attitude and become masters of specialized functions.

Fat-regenerating ‘stem cells’ found in mice

Researchers have identified stem cells with the capacity to build fat, according to a report in the October 17th issue of the journal Cell, a Cell Press publication. Although they have yet to show that the cells can renew themselves, transplants of the progenitor cells isolated from the fat tissue of normal mice can restore normal fat tissue in animals that are otherwise lacking it.

The findings may yield insight into the causes of obesity, a condition characterized by an increase in both the size and number of fat cells.

The role of stem cells in renewing the cornea

A group of researchers in Switzerland has published a study appearing in the Oct 1 advance online edition of the Journal Nature that shows how the cornea uses stem cells to repair itself.

Using mouse models they demonstrate that everyday wear and tear on the cornea is repaired from stem cells residing in the corneal epithelium, and that more serious repair jobs require the involvement of other stem cells that migrate from the limbus, a region between the cornea and the conjunctiva, the white part of the eye.

New method for creating inducible stem cells is remarkably efficient

Some of the most challenging obstacles limiting the reprogramming of mature human cells into stem cells may not seem quite as daunting in the near future. Two independent research papers, published by Cell Press in the September 11th issue of the journal Cell Stem Cell, describe new tools that provide invaluable platforms for elucidating the molecular, genetic, and biochemical mechanisms associated with reprogramming. The new findings also offer considerable hope toward making the reprogramming process more therapeutically relevant.

Stem Cells Restore Muscle In Mice With Muscular Dystrophy

Researchers at the Joslin Diabetes Center have demonstrated for the first time that transplanted muscle stem cells can both improve muscle function in animals with a form of muscular dystrophy and replenish the stem cell population for use in the repair of future muscle injuries.

Genes That Control Embryonic Stem Cell Fate Identified

Scientists have identified about two dozen genes that control embryonic stem cell fate. The genes may either prod or restrain stem cells from drifting into a kind of limbo, they suspect. The limbo lies between the embryonic stage and fully differentiated, or specialized, cells, such as bone, muscle or fat.

By knowing the genes and proteins that control a cell’s progress toward the differentiated form, researchers may be able to accelerate the process — a potential boon for the use of stem cells in therapy or the study of some degenerative diseases, the scientists say.

Elusive pancreatic stem cells found in adult mice

Just as many scientists had given up the search, researchers have discovered that the pancreas does indeed harbor stem cells with the capacity to generate new insulin-producing beta cells. If the finding made in adult mice holds for humans, the newfound progenitor cells will represent an obvious target for therapeutic regeneration of beta cells in diabetes, the researchers report in the Jan. 25 issue of Cell, a publication of Cell Press.

Protein that controls hair growth also keeps stem cells slumbering

Like fine china and crystal, which tend to be used sparingly, stem cells divide infrequently. It was thought they did so to protect themselves from unnecessary wear and tear. But now new research from Rockefeller University has unveiled the protein that puts the brakes on stem cell division and shows that stem cells may not need such guarded protection to maintain their potency.

Stem-cell transplantation improves muscles in muscular dystrophy animal model

Using embryonic stem cells from mice, UT Southwestern Medical Center researchers have prompted the growth of healthy – and more importantly, functioning – muscle cells in mice afflicted with a human model of Duchenne muscular dystrophy.

The study represents the first time transplanted embryonic stem cells have been shown to restore function to defective muscles in a model of muscular dystrophy.

New insight into factors that drive muscle-building stem cells

A report in the January issue of Cell Metabolism, a publication of Cell Press, provides new evidence explaining how stem cells known as satellite cells contribute to building muscles up in response to exercise. These findings could lead to treatments for reversing or improving the muscle loss that occurs in diseases such as cancer and AIDS as well as in the normal aging process, according to the researchers.

Human embryonic stem cell lines created that avoid immune rejection

Scientists from International Stem Cell (ISC) Corp. derived four unique embryonic stem cell lines that open the door for the creation of therapeutic cells that will not provoke an immune reaction in large segments of the population. The stem cell lines are “HLA-homozygous,” meaning that they have a simple genetic profile in the critical areas of the DNA that code for immune rejection. The lines could serve to create a stem cell bank as a renewable source of transplantable cells for use in cell therapy to replace damaged tissues or to treat genetic and degenerative diseases.

UC Irvine scientists find new way to sort stem cells

UC Irvine scientists have found a new way to sort stem cells that should be quicker, easier and more cost-effective than current methods. The technique could in the future expedite therapies for people with conditions ranging from brain and spinal cord damage to Alzheimer’s and Parkinson’s diseases.

In a major breakthrough scientists reprogram human adult cells into embryonic stem cells

Acclaimed stem cell researcher Shinya Yamanaka, MD, PhD, has reported that he and his Kyoto University colleagues have successfully reprogrammed human adult cells to function like pluripotent embryonic stem (ES) cells. Because it circumvents much of the controversy and restrictions regarding generation of ES cells from human embryos, this breakthrough, reported in the journal Cell, should accelerate the pace of stem cell research.

Researchers take first steps towards spinal cord reconstruction following injury

A new study has identified what may be a pivotal first step towards the regeneration of nerve cells following spinal cord injury, using the body’s own stem cells.

This seminal study, published in this week’s Proceedings of the National Academy of Science, identifies key elements in the body’s reaction to spinal injury, critical information that could lead to novel therapies for repairing previously irreversible nerve damage in the injured spinal cord.

Human embryonic stem cells remain embryonic because of epigenetic factors

A human embryonic stem cell is reined in – prevented from giving up its unique characteristics of self-renewal and pluripotency – by the presence of a protein modification that stifles any genes that would prematurely instruct the cell to develop into heart or other specialized tissue. But, thanks to the simultaneous presence of different protein modifications, stem cells are primed and poised, ready to develop into specialized body tissue, Singapore scientists reported in last month’s issue of the journal Cell Stem Cell.

Newly created cancer stem cells could aid breast cancer research

In some ways, certain tumors resemble bee colonies, says pathologist Tan Ince. Each cancer cell in the tumor plays a specific role, and just a fraction of the cells serve as “queens,” possessing the unique ability to maintain themselves in an unspecialized state and seed new tumors. These cells can also divide and produce the “worker” cells that form the bulk of the tumor.

These “queens” are cancer stem cells. Now the lab of Whitehead Member Robert Weinberg has created such cells in a Petri dish by isolating and transforming a particular population of cells from human breast tissue. After being injected with just 100 of these transformed cells, mice developed tumors that metastasized (spread to distant tissues).

Repairing damaged retinas is now a possibility

Japanese researchers from RIKEN and Kyoto University have demonstrated retinal regeneration in a mammalian model of retinal degeneration after stimulation of the Wnt signaling pathway, which functions as a regulator of some adult stem cell populations—in addition to its better known roles in embryogenesis and development.It is a discovery that may ultimately lead to new therapies for retinal diseases including the degenerative disease called retinitis pigmentosa.

Toward an alternative to stem cells for treating chronic brain diseases

With ethical issues concerning use of discarded embryos and technical problems hindering development of stem cell therapies, scientists in Korea are reporting the first successful use of a drug-like molecule to transform human muscle cells into nerve cells. Their report, scheduled for the August 8 issue of the Journal of the American Chemical Society, a weekly journal, states that the advance could lead to new treatments for stroke, Alzheimer’s disease, Parkinson’s disease and other neurological disorders.

 

Scientists identifies gene that regulates blood-forming fetal stem cells

In the rancorous public debate over federal research funding, stem cells are generally assigned to one of two categories: embryonic or adult. But that’s a false dichotomy and an oversimplification. A new University of Michigan study adds to mounting evidence that stem cells in the developing fetus are distinct from both embryonic and adult stem cells.

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.

Stem cells enhance hearing recovery

Researchers have shown that bone marrow stem cells injected into a damaged inner ear can speed hearing recovery after partial hearing loss. The related report by Kamiya et al, “Mesenchymal stem cell transplantation accelerates hearing recovery through the repair of injured cochlear fibrocytes,” appears in the July issue of The American Journal of Pathology.

Scientists find key to stem cell immortality

One of the medical marvels of stem cells is that they continue to divide and renew themselves when other cells would quit. But what is it that gives stem cells this kind of immortality. Researchers now report in the June 16, 2005 issue of the journal Nature that microRNAs — tiny snippets of genetic material that have now been linked to growth regulation in normal cells as well as cancer growth in abnormal cells — appear to shut off the “stop signals” or brakes that would normally tell cells to stop dividing.

In a major breakthrough scientists find new way to create stem cells without embryos

Stem cells with the capacity to form any type of tissue can be created from adult cells without destroying embryos, according to new research that suggests a way of sidestepping ethical controversy over the field.

Three separate teams of scientists have used genetic trickery to wind back the biological clock of mature skin cells from mice, to give them the unlimited potential of stem cells that are normally found only in embryos.

Though it remains uncertain whether the same technique would work in humans, the successes raise the prospect that powerful master cells for use in medicine and research could one day be created from adult bodies, removing any need to use embryos.

Read the article at Times Online site

Muscle Repair Depends on Multiple Cell Types

Researchers have identified a new population of stem cells that act to repair muscle after damage.

Until now, researchers had assumed that all of these cells, which are called satellite cells, had similar properties. They all seemed to follow the same developmental path to becoming mature muscle. The new discoveries show that the developmental fate of a given satellite cell depends on its physical orientation immediately after cell division.

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.

Precursor Cells Generated From Human Embryonic Stem Cells Show Ability to Repair Vascular Damage

Scientists reported for the first time that hemangioblast precursor cells derived from human embryonic stem (hES) cells can be used to achieve vascular repair.

The research, which appears today online (ahead of print) in the journal Nature Methods, by Advanced Cell Technology (ACT) and its collaborators, describes an efficient method for generating large numbers of bipotential progenitors–known as hemangioblasts–from hES cells that are capable of differentiating into blood vessels, as well as into all blood and immune cell lineages.

When smell cells fail they call in stem cell reserves

Hopkins researchers have identified a backup supply of stem cells that can repair the most severe damage to the nerves responsible for our sense of smell. These reservists normally lie around and do nothing, but when neighboring cells die, the scientists say, the stem cells jump into action. A report on the discovery will appear online next week in Nature Neuroscience.

Stem cell transplantation may treat type 1 diabetes

A therapy that includes stem cell transplantation induced extended insulin independence in patients with type 1 diabetes mellitus, according to a preliminary study in the April 11 issue of JAMA.

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.

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.

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.

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.

Super-thin membrane, 50 atoms thick, sorts individual molecules

A newly designed porous membrane, so thin it’s invisible edge-on, may revolutionize the way doctors and scientists manipulate objects as small as a molecule.

The 50-atom thick filter can withstand surprisingly high pressures and may be a key to better separation of blood proteins for dialysis patients, speeding ion exchange in fuel cells, creating a new environment for growing neurological stem cells, and purifying air and water in hospitals and clean-rooms at the nanoscopic level.

Scientists clone mice from adult skin stem cells

For cells that hold so much promise, stem cells’ potential has so far gone largely untapped. But new research from Rockefeller University and Howard Hughes Medical Institute scientists now shows that adult stem cells taken from skin can be used to clone mice using a procedure called nuclear transfer. The findings are reported in the Feb. 12 online edition of the Proceedings of the National Academy of Sciences.

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.

Researchers identify stem cells in pancreatic cancer

Researchers have discovered the small number of cells in pancreatic cancer that are capable of fueling the tumor’s growth. The finding is the first identification of cancer stem cells in pancreatic tumors.

Cancer stem cells are the small number of cancer cells that replicate to drive tumor growth. Researchers believe current cancer treatments sometimes fail because they are not attacking the cancer stem cells. By identifying the stem cells, researchers can then develop drugs to target and kill these cells.

This is particularly crucial for pancreatic cancer, which has the worst survival rate of any major cancer type. Nearly everyone who develops pancreatic cancer dies from the disease.

The Incredible, Medical Egg

Genetically modified chickens that produce medicines in their eggs may be the drug factories of the future. The chicken egg has a storied history in medicine. Even today, millions of ordinary fertilized eggs are each punctured with a drill and injected with flu virus to make vaccines. Now, scientists at the same research institute that cloned Dolly the sheep have produced a genetically modified rooster whose female descendants lay eggs that produce medicines in place of a protein in egg whites.

Helen Sang of the Roslin Institute in Edinburgh, Scotland, and her colleagues used lentivirus to introduce a gene into freshly fertilized chicken embryos that trigger the production of various drugs rather than the protein ovalbumin, which normally makes up roughly 54 percent of egg whites. The researchers screened the resultant cockerels for one that produced the new gene in its semen. They then bred him with normal hens to produce a flock of chickens that carried the inserted gene thereby producing medicines in their egg’s whites.

Read rest of the story at Scientific American

Brain tumor researchers find their ‘niche’

Brain tumors appear to arise from cancer stem cells (CSCs) that live within microscopic protective “niches” formed by blood vessels in the brain; and disrupting these niches is a promising strategy for eliminating the tumors and preventing them from re-growing, according to results of a study by investigators at St. Jude Children’s Research Hospital. CSCs are cells that continually multiply, acting as the source of tumors.

“The finding that brain CSCs exist in protective vascular (blood vessel) niches helps explain the origin of brain tumors and suggests a new strategy for eliminating them,” said Richard Gilbertson, M.D., Ph.D., co-director of the Neurobiology and Brain Tumor Program at St. Jude. Gilbertson is senior author of a report on this work that appears in the January issue of Cancer Cell.

Stem cell marker identified in head and neck cancer

Researchers have found a marker on head and neck tumor cells that indicates which cells are capable of fueling the cancer’s growth. The finding is the first evidence of cancer stem cells in head and neck tumors.

Cancer stem cells are the small number of cancer cells that replicate to drive tumor growth. Researchers believe current cancer treatments sometimes fail because they are not attacking the cancer stem cells. By identifying the stem cells, researchers can then develop drugs to target and kill these cells.

Researchers map gene that regulates adult stem cell growth

The researchers genetically mapped a stem cell gene and its protein product, Laxetin, and building on that effort, carried the investigation all the way through to the identification of the gene itself. This is the first time such a complete study on a stem cell gene has been carried out. This particular gene is important because it helps regulate the number of adult stem cells in the body, particularly in bone marrow. Now that it has been identified, researchers hope the gene, along with its protein product Latexin, can be used clinically, such as for ramping up the stem cell count in cancer patients undergoing chemotherapy and bone marrow transplantation.

The researchers agreed that this very process is not only interesting, but important because of its usefulness in a wide variety of future genetics studies.

Neural stem cells lend the brain a surprising capacity for self-repair

The brain contains stem cells with a surprising capacity for repair, researchers report in recent issue of the journal Cell. The novel insight into the brain’s natural ability to heal might ultimately have clinical implications for the treatment of brain damage, according to the researchers.

The researchers found that mice whose brains were severely damaged by loss of the genes “Numb” and “Numblike” in one region just after birth showed substantial mending within weeks. They attributed that repair to neural stem cell “escapees” that had somehow retained or restored the genes’ activity and, with it, their regenerative potential.

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.

Scientists discover new, readily available source of stem cells

Scientists have discovered a new source of stems cells and have used them to create muscle, bone, fat, blood vessel, nerve and liver cells in the laboratory. The first report showing the isolation of broad potential stem cells from the amniotic fluid that surrounds developing embryos was published in Nature Biotechnology.

“Our hope is that these cells will provide a valuable resource for tissue repair and for engineered organs as well,” said Anthony Atala, M.D., senior researcher and director of the Institute for Regenerative Medicine at Wake Forest University School of Medicine.

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.

Scientists create 3-D scaffold for growing stem cells

Stem cells grew, multiplied and differentiated into brain cells on a new three-dimensional scaffold of tiny protein fragments designed to be more like a living body than any other cell culture system.

An MIT engineer and Italian colleagues will report the invention-which may one day replace the ubiquitous Petri dish for growing cells-in the Dec. 27th issue of the PLoS ONE. Shuguang Zhang, associate director of MIT’s Center for Biomedical Engineering, is a pioneer in coaxing tiny fragments of amino acids called self-assembling peptides to organize themselves into useful structures. Working with visiting graduate student Fabrizio Gelain from Milan, Zhang created a designer scaffold from a network of protein nanofibers, each 5,000 times thinner than a human hair and containing pores up to 20,000 times smaller than the eye of a needle.

The researchers were able to grow a healthy colony of adult mouse stem cells on the three-dimensional scaffold without the drawbacks of two-dimensional systems.

Stem cells as cancer therapy

It is widely hoped that neural stem cells will eventually be useful for replacing nerves damaged by degenerative diseases like Alzheimer disease and multiple sclerosis. But there may also be another use for such stem cells–delivering anti-cancer drugs to cancer cells.

A Perspective article in PLoS Medicine, by Professor Riccardo Fodder, discusses a new study in mice, published in the launch issue of PLoS ONE (www.plosone.org), that showed that neural stem cells could be used to help deliver anti-cancer drugs to metastatic cancer cells.

Muscle and bone from an ink-jet printer

A Pittsburgh-based research team has created and used an innovative ink-jet system to print “bio-ink” patterns that direct muscle-derived stem cells from adult mice to differentiate into both muscle cells and bone cells. The results, which could revolutionize the design of replacement body tissues, will be presented Sunday, Dec. 10 at the 46th annual meeting of the American Society for Cell Biology in San Diego.

This report is the first describing a system that can pattern the formation of multiple cell types within the same vessel from a single population of adult stem cells. The new preclinical advance in the field of regenerative medicine could one day benefit millions of people whose tissues are damaged from a variety of conditions, including fatal genetic diseases like Duchenne Muscular Dystrophy (DMD), wear and tear associated with aging joints, accidental trauma, and joint deterioration due to autoimmune disorders.