Monday, November 30, 2009

New Stem Cell Technology Provides Rapid Healing from Complicated Bone Fractures

Source: The Hebrew University of Jerusalem
Date: November 30, 2009

Summary:

A novel technology involving use of stem cells, developed by Hebrew University of Jerusalem researchers, has been applied to provide better and rapid healing for patients suffering from complicated bone fractures. The technology, involving isolation of the stem cells from bone marrow, was developed by Dr. Zulma Gazit, Dr. Gadi Pelled, Prof. Dan Gazit and their research team at the Skeletal Biotechnology Laboratory at the Hebrew University Faculty of Dental Medicine and was given public exposure in an article that appeared in the journal Stem Cells. The technology has now successfully been used to treat complicated fractures in seven patients at the Hadassah University Hospital in Ein Kerem, Jerusalem.

For First Time, Study Proves Stem Cell Therapy for Heart Patients Is Safe

Source: University of Miami Miller School of Medicine
Date: November 30, 2009

Summary:

An FDA-approved clinical trial is the first to show that treating patients with adult stem cells after a heart attack is safe and that it appears to repair damaged heart tissue. Results of the study are published in the December 8 issue of the Journal of the American College of Cardiology.

The trial, lead by Joshua M. Hare, M.D., director of the Interdisciplinary Stem Cell Institute at the University of Miami Miller School of Medicine, found that the stem cell-treated patients had lower rates of side effects, such as cardiac arrhythmias. Moreover, "they had significant improvements in heart, lung and global function," Hare explained. "Echocardiography showed improved heart function, particularly in those patients with large amounts of cardiac damage."

The Phase I trial was designed to determine the safety and efficacy of administering Prochymal, an intravenous formulation of adult mesenchymal stem cells, in patients within days of a heart attack to lessen damage to the heart muscle. Fifty-three patients who had suffered a heart attack within one to ten days, were randomized to one of three doses of stem cells, and each dose was compared with placebo. Researchers evaluated treatment-related serious adverse affects after six months and used echocardiography to assess efficacy.

Wednesday, November 25, 2009

New Source Discovered for the Generation of Nerve Cells in the Brain

Source: Helmholtz Zentrum München - German Research Center for Environmental Health
Date: November 25, 2009

Summary:

The research group of Professor Magdalena Götz of Helmholtz Zentrum München and Ludwig-Maximilians-Universität (LMU) Munich has made a significant advance in understanding regeneration processes in the brain. The researchers discovered progenitor cells which can form new glutamatergic neurons following injury to the cerebral cortex. Particularly in Alzheimer's disease, nerve cell degeneration plays a crucial role. In the future, new therapeutic options may possibly be derived from steering the generation and/or migration mechanism. These findings have been published in the current issue of the journal Nature Neuroscience.

Monday, November 23, 2009

When is a stem cell really a stem cell?

Source: Children's Hospital Boston
Date: November 23, 2009

Summary:

Induced pluripotent stem (iPS) cells -- adult cells reprogrammed to look and function like versatile embryonic stem cells -- are of growing interest in medicine. They may provide a way to create different kinds of patient-matched stem cells as treatments for disease, while sidestepping many of the ethical questions surrounding stem cells created from embryos. However, the production of iPS cells is often imprecise, yielding many incompletely reprogrammed cells. Now, researchers at Children's Hospital Boston have developed a technique to help distinguish these cells from the desired pure stem cells.

Rather than relying on single markers to determine a stem cell's status, the new method uses a series of tests to identify the signature of a fully reprogrammed, completely undifferentiated pluripotent stem cell that has the potential to become any type of human cell. The series includes tests for fluorescent markers and tumor formation, as well as karyotyping (examination of the number and composition of a cell's chromosomes) and tests for other molecular characteristics of pluripotency.

The study was published Oct. 11 in the journal Nature Biotechnology.

New discovery about the formation of new brain cells

Source: University of Gothenburg
Date: November 23, 2009

Summary:

The generation of new nerve cells in the brain is regulated by a peptide known as C3a, which directly affects the stem cells' maturation into nerve cells and is also important for the migration of new nerve cells through the brain tissue, reveals new research from the Sahlgrenska Academy published in the journal Stem Cells. Although the research has been carried out using mice and cultured cells, it could lead to a new medicine for human beings, which could be given to patients who have had a stroke or other disorders that damage or destroy the nerve cells.

StemCells, Inc. Initiates Landmark Trial Targeting "Communication Highway" of the Brain

Source: StemCells, Inc.
Date: November 23, 2009


In an official company news release, Stem Cells, Inc., a biotechnology company in the field of stem cell research, announced commencement of patient recruitment for a clinical trial to test the safety of human neural stem cells in Pelizaeus-Merzbacher Disease ( PMD), a pediatric neurological disorder:

StemCells, Inc. announced today that it has commenced patient recruitment for a Phase I clinical trial designed to test the safety and preliminary efficacy of its HuCNS-SC® purified human neural stem cells in Pelizaeus-Merzbacher Disease ( PMD), a neurological disorder that primarily afflicts children. The study is being conducted at the University of California, San Francisco (UCSF) Children’s Hospital, one of the leading medical centers in the United States for neonatology, pediatric neurology and neurosurgery.


Here is a video featuring Stem Cells, Inc. CEO Martin McGlynn that explains the trial in greater detail.

Stem Cells That “Fool” Immune System May Provide Vaccination for Cancer

Source: University of Connecticut
Date: November 23, 2009

Summary:

University of Connecticut Health Center researchers in collaboration with scientists from China have revealed the potential for human stem cells to provide a vaccination against colon cancer, reports a study published in October in STEM CELLS. This discovery, led by immunology experts Dr. Bei Liu and Dr. Zihai Li, builds upon a century-old theory that immunizing with embryonic materials may generate an anti-tumor response. However, this theory has never before been advanced beyond the use of animal embryonic materials, and the discovery that human stem cells are able to immunize against colon cancer is both new and unexpected.

New research shows versatility of amniotic fluid stem cells

Source: Wake Forest University Baptist Medical Center
Date: November 23, 2009

Summary:

WINSTON-SALEM, N.C. – For the first time, scientists have demonstrated that stem cells found in amniotic fluid meet an important test of potential to become specialized cell types, which suggests they may be useful for treating a wider array of diseases and conditions than scientists originally thought. Reporting in Oncogene, a publication of Nature Publishing Group, the research teams of Anthony Atala, M.D., director of the Wake Forest Institute for Regenerative Medicine, and Markus Hengstschläger, Ph.D., from the Medical University of Vienna, have shown that these amnion stem cells can form three-dimensional aggregates of cells known as embryoid bodies (EBs). It is believed that cells at this stage of development can be directed to become virtually any cell in the human body.

Thursday, November 19, 2009

First Reconstitution of an Epidermis from Human Embryonic Stem Cells

Source: INSERM (Institut national de la santé et de la recherche médicale)
Date: November 20, 2009

Summary:

In a a study carried out by the I-STEM* Institute (I-STEM/ Inserm UEVE U861/AFM) in France, published in The Lancet on 21 November 2009, researchers have just succeeded in recreating a whole epidermis from human embryonic stem cells. The goal is to one day be able to propose this unlimited resource of cells as an alternative treatment in particular for victims of third degree burns.

Below are links to media coverage of this development from various news sources:

Scientific American

New Scientist

The Times

HealthDay News

WebMD

BBC News

Agence France Presse (AFP)

Scotsman

Advanced Cell Technology Files IND With FDA For First Human Clinical Trial Using Embryonic Stem Cells to Treat Eye Disease

Source: Advanced Cell Technology, Inc.
Posted: November 19, 2009 10:00 AM ET

Summary:

In an official company news release, Advanced Cell Technology, Inc. a biotechnology company in the field of stem cell research, announced it has filed an application with the Food & Drug Administration to begin a study using embryonic treat patients with Stargardt’s Macular Dystrophy (SMD), a degenerative eye disease:

WORCESTER, Mass.--Advanced Cell Technology, Inc. announced today that it filed an Investigational New Drug (IND) Application with the US Food and Drug Administration (FDA) to initiate a Phase I/II multicenter study using embryonic stem cell derived retinal cells to treat patients with Stargardt’s Macular Dystrophy (SMD). Among the most common causes of untreatable blindness in the world are degenerative diseases of the retina. As many as 10 million people in the United States have photoreceptor degenerative disease. While most of these patients have Age-Related Macular Degeneration (AMD), a smaller number of patients have Stargardt’s, an Orphan disease and one of the most common forms of juvenile macular blindness. The treatment for eye disease uses stem cells to re-create a type of cell in the retina that supports the photoreceptors needed for vision. These cells, called retinal pigment epithelium (RPE), are often the first to die off in SMD and AMD, which in turn leads to loss of vision.

Drug studied as possible treatment for spinal injuries

Source: Purdue University
Date: November 19, 2009

Summary:

Researchers have shown how an experimental drug might restore the function of nerves damaged in spinal cord injuries by preventing short circuits caused when tiny "potassium channels" in the fibers are exposed. The chemical compound also might be developed as a treatment for multiple sclerosis. Because nerves usually are not severed in a common type of spinal cord trauma, called "compression" injuries, the drug offers hope as a possible treatment, said Riyi Shi, a professor in Purdue University's Department of Basic Medical Sciences, School of Veterinary Medicine, Center for Paralysis Research and Weldon School of Biomedical Engineering.

Tuesday, November 17, 2009

Stem cells alleviate tumor treatment side effects

Source: University of California- Irvine
Date: November 17, 2009

Summary:

Human embryonic stem cells could help people with learning and memory deficits after radiation treatment for brain tumors, suggests a new UC Irvine study. Research with rats found that transplanted stem cells restored learning and memory to normal levels four months after radiotherapy. In contrast, irradiated rats that didn't receive stem cells experienced a more than 50 percent drop in cognitive function.

"Our findings provide the first evidence that such cells can be used to ameliorate radiation-induced damage of healthy tissue in the brain," says Charles Limoli, UCI radiation oncology associate professor and senior author of the study, appearing online the week of Nov. 9 in the Proceedings of the National Academy of Sciences.

Your own stem cells can treat heart disease: Transplanting people’s own stem cells into heart lessens pain, improves ability to walk

Source: Northwestern University
Date: November 18, 2009

Summary:

CHICAGO ---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 patients with severe angina results in less pain and an improved ability to walk. They also experienced fewer deaths than those who didn't receive stem cells. The stem cells were injected in an effort to spur the growth of small blood vessels in the heart muscle.

Here is a story from HealthDay News about this development.

On your last nerve: Researchers advance understanding of stem cells

Source: North Carolina State University
Date: November 17, 2009

Summary:

Researchers from North Carolina State University have identified a gene that tells embryonic stem cells in the brain when to stop producing nerve cells called neurons. The research is a significant advance in understanding the development of the nervous system, which is essential to addressing conditions such as Parkinson's disease, Alzheimer's disease and other neurological disorders.

Sunday, November 15, 2009

Researchers find potential treatment for Huntington's disease

Source: Burnham Institute for Medical Research
Date: November 15, 2009

Summary:

Investigators at Burnham Institute for Medical Research, the University of British Columbia's Centre for Molecular Medicine and Therapeutics and the University of California, San Diego have found that normal synaptic activity in nerve cells (the electrical activity in the brain that allows nerve cells to communicate with one another) protects the brain from the misfolded proteins associated with Huntington's disease.

In contrast, excessive extrasynaptic activity (aberrant electrical activity in the brain, usually not associated with communication between nerve cells) enhances the misfolded proteins' deadly effects. Researchers also found that the drug Memantine, which is approved to treat Alzheimer's disease, successfully treated Huntington's disease in a mouse model by preserving normal synaptic electrical activity and suppressing excessive extrasynaptic electrical activity. The research was published in the journal Nature Medicine on November 15.

Friday, November 13, 2009

How Does The Pancreas In An Embryo ‘Know’ Which Cells Are To Produce Insulin?

Source: Lund University
Date: November 13, 2009

Summary:

How does the developing pancreas in an embryo 'know' which cells are to produce insulin and which cells are to have other assignments? Researchers need to understand this if they want to be able to treat type-1 diabetes with stem cells developed into insulin-producing beta cells. At Lund University scientists have uncovered pioneering new knowledge, and are publishing it in the journal Cell.

Thursday, November 12, 2009

Coverage Summary: UC Irvine Embryonic Stem Cell Cognitive Function Restoration Study

Below is a summary of news coverage of the recent announcement by researchers at University of California, Irvine that embryonic stem cells restored cognitive function in brains damaged by radiation:

Ivanhoe Newswire, November 12, 2009: "Stem Cells Restore Brain Function":

Human embryonic stem cells could reverse learning and memory deficits people experience after undergoing radiation treatment for brain tumors. Research with rats found that transplanted stem cells restored learning and memory to normal levels four months after radiation therapy. In contrast, irradiated rats that didn't receive stem cells experienced a more than 50 percent drop in cognitive function.

Los Angeles Times Health, November 10, 2009: "Embryonic stem cells may restore brains damaged by radiation":

Scientists at UC Irvine and UC San Francisco have found a potential new use for human embryonic stem cells – helping cancer patients recover the cognitive function lost when their brains are treated with radiation. People with tumors in their head or neck often undergo radiation therapy after the cancer is surgically removed. That radiation helps kill off any malignant cells left behind. But it can also debilitate the region of the brain called the hippocampus, which is responsible for learning, memory and processing of spatial information. It is also one of only two areas in the brain known to produce new neurons.

Agence France Presse (AFP), November 10, 2009: "Stems cells repair brain function in irradiated rats":

WASHINGTON — Human embryonic stem cells may one day be used to help people recover abilities to learn and remember that are lost after radiation treatment for brain tumors, experiments on rats suggest. In a study published Monday in the Proceedings of the National Academy of Sciences, researchers found that transplanted stem cells in rats restored learning and memory within four months of radiotherapy.

Wednesday, November 11, 2009

Mouse Gene Suppresses Alzheimer’s Plaques and Tangles

Source: Burnham Institute for Medical Research
Date: November 11, 2009

Summary:

Investigators at Burnham Institute for Medical Research (Burnham) and colleagues have identified a novel mouse gene (Rps23r1) that reduces the accumulation of two toxic proteins that are major players in Alzheimer’s disease: amyloid beta and tau. The amyloid and tau lowering functions of this gene were demonstrated in both human and mouse cells. Amyloid beta is responsible for the plaques found in the brains of Alzheimer’s patients. Tau causes the tangles found within patients’ brain cells. The study was published in the journal Neuron on November 12. These findings could lead to new treatments for Alzheimer’s disease.

Longevity tied to genes that preserve tips of chromosomes

Albert Einstein College of Medicine
November 11, 2009

Summary:

A team led by researchers at Albert Einstein College of Medicine of Yeshiva University has found a clear link between living to 100 and inheriting a hyperactive version of an enzyme that rebuilds telomeres – the tip ends of chromosomes. The findings appear in the latest issue of the Proceedings of the National Academy of Sciences.

In investigating the role of telomeres in aging, the Einstein researchers studied Ashkenazi Jews because they are a homogeneous population that was already well studied genetically. Three groups were enrolled: 86 very old — but generally healthy —
Gil Atzmon, Ph.D.people (average age 97); 175 of their offspring; and 93 controls (offspring of parents who had lived a normal lifespan).

Researchers found that participants who have lived to a very old age have inherited mutant genes that make their telomerase-making system extra active and able to maintain telomere length more effectively. For the most part, these people were spared age-related diseases such as cardiovascular disease and diabetes, which cause most deaths among elderly people.

Geron Collaborators Publish Data on hESC-Derived Glial Progenitor Cell Therapy in Cervical Spinal Cord Injury

Source: Geron Corporation
Date: November 11, 2009

Summary:

Geron Corporation today announced the publication of data showing that oligodendrocyte progenitor cells (OPCs) derived from human embryonic stem cells (hESCs), when transplanted into a rodent model of cervical spinal cord injury, reduced tissue damage within the lesion and improved recovery of locomotor function. These data provide preclinical proof-of-concept for the use of GRNOPC1, Geron's hESC-derived oligodendrocyte progenitor product, in patients with cervical spinal cord injuries. Over half of the 11,000 human spinal cord injuries that are sustained in the U.S. annually are in the cervical region.

The study was authored by Geron collaborator Dr. Hans S. Keirstead and colleagues at the Reeve-Irvine Research Center and the Sue & Bill Gross Stem Cell Research Center at the University of California at Irvine. The paper was published online in advance of print in the journal Stem Cells.

Monday, November 09, 2009

Stem cells restore cognitive abilities impaired by brain tumor treatment, UCI study finds

Source: University of California - Irvine
Date: November 9, 2009

Summary:

Human embryonic stem cells could help people with learning and memory deficits after radiation treatment for brain tumors, suggests a new UC Irvine study appearing online the week of Nov. 9 in the Proceedings of the National Academy of Sciences. Research with rats found that transplanted stem cells restored learning and memory to normal levels four months after radiotherapy. In contrast, irradiated rats that didn't receive stem cells experienced a more than 50 percent drop in cognitive function. In the UCI study, stem cells were transplanted into the heads of rats that had undergone radiation treatment. They migrated to a brain region known to support the growth of neurons, scientists observed, and developed into new brain cells.

Researchers discover new source of brain cells. Discovery could speed progress on stem cell treatments of brain disorders

Source: University of California - Davis
Date: November 9, 2009

Summary:

(SACRAMENTO, Calif.) — Twenty-six years after scientists first suspected their existence, UC Davis researchers provide definitive evidence that certain neural progenitor cells, which can be identified by their expression of a myelin gene promoter, are present throughout the adult brain and spinal cord, and that these cells are capable of differentiating into neurons.

Using genetic fate mapping — a technique for detailing the developmental path of cells — Pleasure and his team found that cells known as PPEPs (pronounced pee-peps) differentiate into the three main types of neural cells: astrocytes, oligodendrocytes and neurons. Neurons are the main cells of the brain, responsible for communicating with each other and responding to stimuli. The other two cell types — known as glial cells — play supporting roles in brain functions.

The findings, reported in June 2009 issue of the Journal of Neuroscience, open up a new way of thinking about using multipotent progenitor cells to treat diseases of the brain and spinal cord, such as Huntington’s disease and traumatic brain injury. Now the UC Davis team and other stem cell scientists have a new class of endogenous neural progenitor cells with which to work.

Embryonic Stem Cell Therapy Restores Walking Ability In Rats With Neck Injuries

Source: University of California - Irvine
Date: November 9, 2009

Summary:

The first human embryonic stem cell treatment approved by the FDA for human testing has been shown to restore limb function in rats with neck spinal cord injuries -- a finding that could expand the clinical trial to include people with cervical damage. In January, the U.S. Food & Drug Administration gave Geron Corp. of Menlo Park, Calif., permission to test the UC Irvine treatment in individuals with thoracic spinal cord injuries, which occur below the neck. However, trying it in those with cervical damage wasn't approved because preclinical testing with rats hadn't been completed.

Results of the cervical study currently appear online in the journal Stem Cells. UCI scientist Hans Keirstead hopes the data will prompt the FDA to authorize clinical testing of the treatment in people with both types of spinal cord damage. About 52 percent of spinal cord injuries are cervical and 48 percent thoracic.

UC Irvine has produced a video that explains the results of this finding.

Sunday, November 08, 2009

Findings show nanomedicine promising for treating spinal cord injuries

Source: Purdue University
Date: November 8, 2009

Summary:

Researchers at Purdue University have discovered a new approach for repairing damaged nerve fibers in spinal cord injuries using nano-spheres that could be injected into the blood shortly after an accident. The synthetic "copolymer micelles" are drug-delivery spheres about 60 nanometers in diameter, or roughly 100 times smaller than the diameter of a red blood cell. Researchers have been studying how to deliver drugs for cancer treatment and other therapies using these spheres. Medications might be harbored in the cores and ferried to diseased or damaged tissue. Purdue researchers have now shown that the micelles themselves repair damaged axons, fibers that transmit electrical impulses in the spinal cord. Findings are detailed in a research paper appearing Sunday (Nov. 8) in the journal Nature Nanotechnology.

Friday, November 06, 2009

Scientists Successfully Reprogram Blood Cells to Correct Lysosomal Storage Disease

Source: Cincinnati Children's Hospital Medical Center
Date: November 6, 2009

Summary:

Researchers have transplanted genetically modified hematopoietic stem cells into mice so that their developing red blood cells produce a critical lysosomal enzyme -preventing or reducing organ and central nervous system damage from the often-fatal genetic disorder Hurler's syndrome. The research team from Cincinnati Children's Hospital Medical Center reports its preclinical laboratory results this week in the early edition of Proceedings of the National Academy of Sciences.

The study suggests a new approach to molecular gene therapy and a much-needed improved treatment option for children with Hurler's syndrome, said Dao Pan, Ph.D., a researcher in the Division of Experimental Hematology/Cancer Biology at Cincinnati Children's and the study's principal author. It also is the first study to demonstrate that
developing red blood cells can be used to produce lysosomal enzymes.

Thursday, November 05, 2009

Gene therapy technique slows ALD brain disease

Source: American Association for the Advancement of Science
Date: 5 November 2009

Summary:

A strategy that combines gene therapy with blood stem cell therapy may be a useful tool for treating a fatal brain disease, French researchers have found. These findings appear in the 6 November 2009 issue of the journal Science. In a pilot study of two patients monitored for two years, an international team of researchers slowed the onset of the debilitating brain disease X-linked adrenoleukodystrophy (ALD) using a lentiviral vector to introduce a therapeutic gene into patient's blood cells. Although studies with larger cohorts of patients are needed, these results suggest that gene therapy with lentiviral vectors, which are derived from disabled versions of human immunodeficiency virus (HIV), could potentially become instrumental in treating a broad range of human disorders.

Study shows neural stem cells in mice affected by gene associated with longevity

Source: Stanford University School of Medicine
November 5, 2009

Summary:

A gene associated with longevity in roundworms and humans has been shown to affect the function of stem cells that generate new neurons in the adult brain, according to researchers at the Stanford University School of Medicine. The study in mice suggests that the gene may play an important role in maintaining cognitive function during aging.

“It’s intriguing to think that genes that regulate life span in invertebrates may have evolved to control stem cell pools in mammals,” said Anne Brunet, PhD, assistant professor of genetics. She is the senior author of the research, published Nov. 6 in Cell Stem Cell.

First use of antibody and stem cell transplantation to successfully treat advanced leukemia

Source: Fred Hutchinson Cancer Research Center
Date: November 5, 2009

Summary:

For the first time, researchers at Fred Hutchinson Cancer Research Center have reported the use of a radiolabeled antibody to deliver targeted doses of radiation, followed by a stem cell transplant, to successfully treat a group of leukemia and pre-leukemia patients for whom there previously had been no other curative treatment options.

All fifty-eight patients, with a median age of 63 and all with advanced acute myeloid leukemia or high-risk myelodysplastic syndrome - a pre-leukemic condition - saw their blood cancers go into remission using a novel combination of low-intensity chemotherapy, targeted radiation delivery by an antibody and a stem-cell transplant. Forty percent of the patients were alive a year after treatment and approximately 35 percent had survived three years, about the same rates as patients who received similar treatment but whose disease was already in remission and who had much more favorable risk for relapse when therapy began.

Results of the research appear online in the journal Blood. The principal investigator and corresponding author of the paper is John Pagel, M.D., Ph.D, a transplant oncologist and assistant member of the Hutchinson Center's Clinical Research Division.

Wednesday, November 04, 2009

Lung tissue generated from human embryonic stem cells

Source: BioMed Central
November 4, 2009

Summary:

Scientists in Belgium have successfully differentiated human embryonic stem cells (hESC) into major cell types of lung epithelial tissue using a convenient air-liquid interface. The technique, published in BioMed Central's open access journal Respiratory Research, could provide an alternative to lung transplants for patients with lung injury due to chronic pulmonary disease and inherited genetic diseases such as cystic fibrosis.

SCIENTISTS REVEAL HOW INDUCED PLURIPOTENT STEM CELLS DIFFER FROM EMBRYONIC STEM CELLS AND TISSUE OF DERIVATION

Source: Johns Hopkins Medicine
Date: November 4, 2009

Summary:

The same genes that are chemically altered during normal cell differentiation, as well as when normal cells become cancer cells, are also changed in stem cells that scientists derive from adult cells, according to new research from Johns Hopkins and Harvard. Although genetically identical to the mature body cells from which they are derived, induced pluripotent stem cells (iPSCs) are notably special in their ability to self-renew and differentiate into all kinds of cells. And now scientists have detected a remarkable if subtle molecular disparity between the two: They have distinct “epigenetic” signatures; that is, they differ in what gets copied when the cell divides, even though these differences aren’t part of the DNA sequence.

Monday, November 02, 2009

Unraveling the mechanisms behind organ regeneration in zebrafish

Source: Salk Institute for Biological Studies
Date: November 2, 2009

Summary:

Unlike humans, zebrafish are able to regenerate amputated appendages. The search for the holy grail of regenerative medicine -- the ability to "grow back" a perfect body part when one is lost to injury or disease -- has been under way for years, yet the steps involved in this seemingly magic process are still poorly understood.

Now researchers at the Salk Institute for Biological Studies have identified an essential cellular pathway in zebrafish that paves the way for limb regeneration by unlocking gene expression patterns last seen during embryonic development. They found that a process known as histone demethylation switches cells at the amputation site from an inactive to an active state, which turns on the genes required to build a copy of the lost limb.

Their findings, which will be published in a forthcoming issue of Proceedings of the National Academy of Sciences, U.S.A., help to explain how epimorphic regeneration—the regrowing of morphologically and functionally perfect copies of amputated limbs—is controlled, an important step toward understanding why certain animals can do it and we cannot.