Scientific American Topic - Stem Cells

The Naked Truth: Why Humans Have No Fur (preview)

Wed, 20 Jan 2010 11:01:00 EST

Among primates, humans are unique in having nearly naked skin. Every other member of our extended family has a dense covering of fur--from the short, black pelage of the howler monkey to the flowing copper coat of the orangutan--as do most other mammals. Yes, we humans have hair on our heads and elsewhere, but compared with our relatives, even the hairiest person is basically bare.

How did we come to be so denuded? Scholars have pondered this question for centuries. Finding answers has been difficult, however: most of the hallmark transitions in human evolution--such as the emergence of upright walking--are recorded directly in the fossils of our predecessors, but none of the known remains preserves impressions of human skin. In recent years, though, researchers have realized that the fossil record does contain indirect hints about our transformation from hirsute to hairless. Thanks to these clues and insights gleaned over the past decade from genomics and physiology, I and others have pieced together a compelling account of why and when humans shed their fur. In addition to explaining a very peculiar quirk of our appearance, the scenario suggests that naked skin itself played a crucial role in the evolution of other characteristic human traits, including our large brain and dependence on language.

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Fetal Cells Return as a Parkinson's Cure

Mon, 11 Jan 2010 08:00:00 EST

President Franklin D. Roosevelt admonished in a 1932 commencement address that “it is common sense to take a method and try it. If it fails, admit it frankly and try another.” FDR had the revival of a depressed U.S. economy in mind, but scientists experimenting with treating brain disorders with fetal cell transplants have taken his aphorism to heart. New methods are transforming past failures, and the results seem far more promising this go-round.

Fetal cell therapy began in earnest in the mid-1980s, among researchers hoping to treat Parkinson’s disease. These patients have trouble controlling their movements partly because their brains lack the neurotransmitter dopamine. The hope was that tissue from fetal midbrains placed into patients’ brains would turn into dopamine-making cells. Shortly after the turn of the century, however, the work foundered when a subset of transplant patients developed disabling movement disorders termed runaway dyskinesias.

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Restoring Cells' Potential is Method of the Year

Thu, 31 Dec 2009 08:32:08 EST

The journal Nature Methods recently announced their method of the year, and it is: induced pluripotency. Embryonic stem cells have the potential to be any type of cells, a characteristic known as pluripotency. In 2006 a researcher in Japan announced that he’d genetically reprogrammed mouse fibroblasts--a type of skin cell--to make them pluripotent. These so-called induced pluripotent stem cells, or IPS cells, could now become any cell. [More]

Vitamin C Boosts the Induction of Pluripotent Stem Cells

Thu, 24 Dec 2009 12:15:00 EST

Soon after the exciting discovery of a method to transform human skin cells into stem cells in 2007 came the frustration of actually trying to make a sufficient amount of these induced pluripotent stem (iPS) cells .* The process is so inefficient that scientists typically only get 0.01 percent of a sample of human skin, or fibroblast, cells to form iPS cell colonies after they infect fibroblasts with the retroviruses used to induce pluripotency. "We almost gave up three years ago," says Dr. Duanqing Pei, director general and professor at the Guangzhou Institutes of Biomedicine and Health in Guangzhou, China. [More]

NIH approves first new stem cell lines for funding since 2001

Thu, 03 Dec 2009 13:35:00 EST

The National Institutes of Health (NIH) gave approval Wednesday for 13 new lines of human embryonic stem cells to be made available to federally funded researchers. The decision ends a logjam that resulted from a Bush administration policy banning government-backed research on lines created after August 9, 2001. President Barack Obama lifted those restrictions in March. [More]

Stem Cells Could Offer New Source for Skin Grafts

Wed, 25 Nov 2009 09:30:00 EST

Researchers are now one step closer to being able to use skin tissue derived from stem cells for the treatment of burn victims, according to a study published November 21 in The Lancet . [More]

For Sale: Human Eggs Become a Research Commodity

Tue, 17 Nov 2009 08:00:00 EST

Paying a woman for her eggs to use in stem cell research has been a bioethical no-no for years. But this past June, New York State decided to allow just that, becoming the first state to permit public money to be used in this way. The decision, which allows payment of up to $10,000, will likely jump-start donations--and thereby research. Many bioethicists, however, worry that the financial incentive could exploit women and compromise their health.

Ethical issues surround egg donation because the process is not without risk. It requires a series of hormonal stimulation injections as well as an invasive procedure to retrieve the eggs. The long-term health effects and risks of complication are not well known. A woman who provides eggs for research is “assuming unknown risk for unknown benefits,” says Debra Mathews, a geneticist at Johns Hopkins University. The lingering unknowns prompted the National Academy of Science to issue in 2005 nonbinding guidelines to prohibit payment (but allow direct reimbursement for expenses), as a means to protect underprivileged women in particular.

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Medicine looks ahead at TED MED

Wed, 28 Oct 2009 08:57:00 EST

“If you open your minds and let your imaginings run wild, you can see.” J. Craig Venter, the genomic scientist and founder of the J. Craig Venter Institute, was speaking yesterday about the potential for techniques involved in the field of synthetic life to improve medicine, but his words could have been applied to the all the talks during the opening session of TED MED (“TED” is for technology, entertainment, design). The conference is running from October 27 through 30 at the Hotel Del Coronado in San Diego. Speakers also described advances in using stem cells for regenerative medicine and tissue engineering.

Venter reviewed recent advances in “software building its own hardware.” That is, by inserting DNA from one organism into another , scientists have been able to use existing cellular machinery to read that DNA--transforming one species to another. He mentioned Phase II clinical trials of a vaccine for meningitis developed with the technique.

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The Root of Thought: What Do Glial Cells Do?

Tue, 27 Oct 2009 10:00:00 EST

Andrew Koob received his Ph.D. in neuroscience from Purdue University in 2005, and has held research positions at Dartmouth College, the University of California, San Diego, and the University of Munich, Germany. He's also the author of The Root of Thought , which explores the purpose and function of glial cells, the most abundant cell type in the brain. Mind Matters editor Jonah Lehrer chats with Koob about why glia have been overlooked for centuries, and how new experiments with glial cells shed light on some of the most mysterious aspects of the mind.

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Beating Heart Tissue from Stem Cells

Thu, 15 Oct 2009 13:57:08 EST

[ The following is an exact transcript of this podcast. ]

One of the goals of regenerative medicine is to make tissue to replace our own damaged body parts. That’s still a ways off. But starting with mouse embryonic stem cells, researchers have succeeded in creating heart muscle that actually beats. The study appears in the October 16th issue of the journal Science .

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Stem Cells from Fat Used to Grow Teen's Missing Facial Bones

Thu, 15 Oct 2009 10:15:00 EST

Stem cells so far have been used to mend tissues ranging from damaged hearts to collapsed tracheas . Now the multifaceted cells have proved successful at regrowing bone in humans. In the first procedure of its kind, doctors at Cincinnati Children's Hospital Medical Center replaced a 14-year-old boy's missing cheekbones--in part by repurposing stem cells from his own body. [More]

Unraveling the Ribosome: Chemistry Nobel Awarded to Modelers of Cells' Protein-Maker [Update]

Wed, 07 Oct 2009 07:20:00 EST

The 2009 Nobel Prize in Chemistry will be split among three researchers who, over the course of the past two decades, puzzled out--at the atomic level--the function of the ribosome in piecing together proteins. [More]

Breakthrough: Bone Graft Grown in Exact Shape of Complex Skull-Jaw Joint

Mon, 05 Oct 2009 16:10:00 EST

Bones often come in complex, delicate shapes, making it hard to find matching natural replacements for them in patients suffering from injuries, diseases or birth defects. Now researchers have grown bone grafts in the exact shape of a desired bone, an advance that could help provide doctors with just what they need for face , skull and other skeletal reconstructions.

Although missing bone can be replaced by titanium , "there is no better substitute for lost tissue than living tissue," bioengineer Gordana Vunjak-Novakovic at Columbia University explains. "Although titanium is better than nothing--you need something to help bear loads--real bones also have bone marrow inside that has many important metabolic functions."

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Work on Telomeres Wins Nobel Prize in Physiology or Medicine for 3 U.S. Genetic Researchers [Update]

Mon, 05 Oct 2009 07:30:00 EST

The 2009 Nobel Prize in Physiology or Medicine will go to three Americans who discovered telomeres , the genetic code that protects the ends of chromosomes, and telomerase , the enzyme that assists in this process, findings that are important in the study of cancer, aging and stem cells. [More]

Stem cells bring new insights to future treatment of vision--and neural--disorders

Thu, 24 Sep 2009 12:30:00 EST

BALTIMORE--Deep in the brain, buried in the hippocampus and subventricular zone, reside adult neural stem cells , cells that retain the ability to become other types of neural cells and could serve as possible treatments for ailments ranging from vision impairment to Parkinson's to spinal cord injuries. Doctors, scientists and patients, however, are understandably hesitant to go digging around for them, their location being "a great deterrent," Sally Temple , founder of the New York Neural Stem Cell Institute, said at the 2009 World Stem Cell Summit here on Wednesday. [More]

Cancer stem cell research gains traction, tackles new targets

Wed, 23 Sep 2009 07:30:00 EST

BALTIMORE--In the decades-long war on cancer, as of late, researchers had been making little progress in comparison to colleagues treating other conditions, such as cardiac or infectious diseases. "Cancer research has really plateaued out," William Matsui , an associate professor of oncology at Johns Hopkins University's School of Medicine, said at the 2009 World Stem Cell Summit here on Tuesday. But pushing cancer stem cell research "gives us a novel way to study cancer," said Matsui, who also runs a lab at the university's Sidney Kimmel Comprehensive Cancer Center . [More]

Where There Was Smoke, There's Science

Tue, 08 Sep 2009 20:00:08 EST

Wake Forest University School of Medicine neuroscientist Dwayne Godwin talks about the the Winston–Salem area's adoption of biomedical research as well as meetings with Congress about science funding and his comic strip contributions to Scientific American Mind . Plus, we'll test your knowledge of some recent science in the news.

Podcast Transcription

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Induced Pluripotent Stem Cells Created from Fat Cells

Tue, 08 Sep 2009 16:35:00 EST

The standard way to make induced pluripotent stem (iPS) cells for medical research is to scrape skin cells and mix up their internal clocks, coaxing them back into pluripotency over a matter of weeks. But now researchers at the Stanford University School of Medicine have turned their attention to another cell type in abundant supply: fat cells. The team of cardiologists and plastic surgeons found adipose fat cells to be much more efficient than skin cells at turning back into stem cells. [More]

Divide to Conquer: Infection-Specific T Cells Multiply to Fight Infection

Thu, 03 Sep 2009 15:30:00 EST

When the body contracts a new virus or bacteria, specific white blood cells --T lymphocytes--are recruited to fight back. Each T cell is only programmed, however, to recognize a specific viral or bacterial strain, so out of every 100,000 T cells, only one might match a novel pathogen. Therefore, once the matches are found, those few cells need to multiply in a hurry to stave off illness. [More]

Researchers Design Patches of Cells to Repair Damaged Hearts

Mon, 24 Aug 2009 19:30:00 EST

Clinical trials are underway for stem cell injections to quicken healing of the cardiac muscle after a heart attack. Although promising results trickle in, other researchers are looking for a speedier way to renew a damaged area of the organ: patches of cardiac cells. One patch is getting a leg up from a temporary stay in stomach tissue, and another is using a biodegradable mesh to help the heart rebuild itself. [More]