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Embryonic stem cell (Science Photo Library)
Entire organs could be grown from stem cells
British scientists have grown part of a human heart from stem cells for the first time.
Wed April 15, 2007 9:05AM EDT

United Kingdom (BBC News) - Heart surgeon Sir Magdi Yacoub, who led the team, said doctors could be using artificially grown heart components in transplants within three years.

His researchers at Harefield hospital managed to grow tissue that works in the same way as human heart valves.

Sir Magdi told the Guardian newspaper a whole heart could be produced from stem cells within 10 years.

'Common pathway'

The team which spent 10 years working on the project included physicists, pharmacologists, clinicians and cellular scientists.

You can see the common pathway of death and suffering is heart failure
Sir Magdi Yacoub

Researchers will see their achievement as a major step towards growing entire organs for transplant.

Stem cells have the potential to turn into many different types of cell.

Many scientists believe it should be possible to harness the cells' ability to grow into different tissues to repair damage and treat disease.

Previously, scientists have grown tendons, cartilages and bladders, which are all less complex.

Sir Magdi, professor of cardiac surgery at Imperial College London, had been working on ways to address a shortage of donated hearts for patients.

Entire heart hope

He said he hoped that soon an entire heart could be grown from stem cells.

He added: "It is an ambitious project but not impossible. If you want me to guess I'd say 10 years."

His team extracted stem cells from bone marrow and cultivated them into heart valve cells.

After they were placed in scaffolds formed from collagen, 3cm-wide discs of heart valve tissue were formed.

Later in the year, these will be implanted into animals such as sheep or pigs to see how well they fare.

Heart valves do not simply open and close like the artificial alternatives currently used in surgery, they are able to anticipate changes in the way the blood flows, and respond accordingly.

Professor Yacoub's team hope the valves they are growing will be equally sophisticated.

No drugs

In theory, if the valve was grown from the patient's own cells there would also be no need to take drugs to stop the body rejecting it.

They would also be potentially much longer lasting than artificial valves, which often have to be replaced after several years.

Dr Adrian Chester, a senior member of the research team, said: "We are attempting to grow a valve that will be functional in adults and children and will be made entirely of living tissue.

"Hopefully it will be able to adapt to its environment, and then just sit there and function just as a normal valve functions under normal physiological conditions."

Dr Chester said ultimately the work could mean that some patients might be able to avoid a heart transplant.

Dr Stephen Minger, a stem cell expert at London's King's College, said Sir Magdi's team were at the forefront of tissue engineering for cardiac disease.

"If the valves they've engineered prove successful in experimental animals, this could open the door to generating complex tissues from stem cells for a wide variety of clinical application.

"But as they stress, this is very preliminary work and the direct translation to human is still some way off in the future."

Professor John Martin of the British Heart Foundation, which supported the research, said: "This opens the possibility that whole parts of the heart may be made in the laboratory from the patient's own stem cells. "

This is very preliminary work and the direct translation to human is still some way off in the future
Dr Stephen Minger
King's College London

He said patients could benefits because using the tissue could prevent the need for a heart transplant.

Professor Martin added: "Although the work carried out the Harefield is exciting there is a long road to be travelled before patients awaiting heart transplants will benefit from this research."

Heart disease is the UK's biggest killer. More than 200,000 people died from heart disease and strokes in 2004.

And in 2003 nearly 10,000 people needed surgery to replace heart valves with artificial ones.

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Bone Marrow Cells Morphed Into Immature Sperm
Wed April 15, 2007 9:05AM EDT

By Maggie Fox

WASHINGTON (Reuters) - Stem cells taken from the bone marrow of men can be coaxed into something that resembles an immature sperm cell, researchers working in Germany said on Friday.

They hope to use their findings to come up with new and better fertility treatments for both men and women.

"Our next goal is to see if we can get the spermatogonial stem cells to progress to mature sperm in the laboratory and this should take around three to five years of experiments," Dr. Karim Nayernia, who led the study while at the University of Gottingen in Germany, said in a statement.

Nayernia, now at Newcastle University and the North East England Stem Cell Institute in Britain, had previously grown sperm cells from mouse bone marrow and used them to fertilize mouse eggs and create living baby mice.

His team worked with men who were about to get bone marrow transplants, a common treatment for cancer.

They removed some of the bone marrow, a rich source of so-called adult stem cells. These stem cells are used by the body to replenish blood, bone, muscle and other tissues.

Writing in the journal Reproduction: Gamete Biology, Nayernia and colleagues said they searched out stem cells that most closely resembled germ cells -- the cells found in the testes of men and ovaries of women that eventually give rise to sperm and eggs. 

"Here we show that a small population of bone marrow cells is able to transdifferentiate to male germ cell-like cells," Nayernia's team wrote.

"Our findings provide direct evidence that human bone marrow cells can differentiate to putative male germ cells and identify bone marrow as a potential source of male germ cells that could sustain sperm production."

Stem cell science counts on being able to redirect a cell so it will create a particular tissue. The more immature a stem cell is, the more malleable it is, which is why many researchers want to work with and study stem cells taken from days-old embryos.

Unlike mature tissue, stem cells live longer, with some types being virtually immortal under the right lab conditions.

If scientists can take bone marrow cells from an infertile man and turn them into sperm, he could father a child using standard techniques such as in vitro fertilization (IVF).

Other researchers have done similar work in female mice, taking bone marrow cells and turning them into egg cells.

Dr. Malcolm Alison of Queen Mary's School of Medicine and Dentistry in London was cautious about the findings. "Before we get too excited about this being a new form of infertility treatment, these cells cannot as yet be made into functioning sperm, so we have no idea if they can pass 'the acid test,' the ability to fertilize female eggs as is achieved with donor sperm in IVF treatment," he said in a statement.

Harry Moore of the Centre for Stem Cell Biology at the University of Sheffield noted that such experiments are very difficult to replicate.

"This is a fast-moving field but we are still many years away from developing any therapies for infertility using such techniques," Moore said.

"Unfortunately, these stem cell manipulations can lead to permanent genetic changes which would make them unsafe to use especially as a potential sperm or egg."

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Heavy coffee drinkers show no blood pressure rise
Wed Mar 21, 2007 1:05PM EDT

By Amy Norton

NEW YORK (Reuters Health) - Coffee lovers who are in good health may have little reason to cut back, at least as far as their blood pressure is concerned, a new study suggests.

Because the caffeine in coffee and other foods can cause a short-term spike in blood pressure, there's been concern that coffee drinking may over time raise the risk of high blood pressure. Studies, however, have come to inconsistent conclusions.

In the new study, published in the American Journal of Clinical Nutrition, researchers found that healthy women who drank upwards of six cups of coffee per day were no more likely than abstainers to develop high blood pressure over the next decade.

On the other hand, women who drank coffee occasionally or in moderation -- reporting anywhere from zero to three cups a day -- had a higher risk of developing high blood pressure than the heavy coffee drinkers or the abstainers.

For men, the risk of high blood pressure did not significantly increase or decrease, regardless of how much coffee they drank each day. However, men who abstained did have a lower risk than any coffee drinkers.

Still, the effect was "relatively small," Dr. Cuno S. P. M. Uiterwaal, the study's lead author, told Reuters Health.

Handing out blanket advice on coffee or any food is difficult, noted Uiterwaal, an associate professor at the University Medical Center Utrecht, in the Netherlands.

But given the overall research on the effects of coffee on healthy people -- including studies that suggest health benefits, like a lower diabetes risk -- there seems to be no reason to discourage them from enjoying their java, according to the researcher.

"The general advice to healthy people, if any, would then be that there is no argument for healthcare workers to advise against coffee drinking," he said.

The findings come from an 11-year follow-up of nearly 6,400 Dutch men and women who were 40 years old, on average, at the study's start. Participants completed detailed questionnaires on their diets, including coffee drinking, as well as other lifestyle habits, education and family medical history.

Over the next 11 years, the researchers found, light coffee drinkers were more likely to develop high blood pressure than either non-drinkers or heavier consumers, with other health factors considered.

A possible reason, according to Uiterwaal's team, is that people who drink several cups of coffee every day develop a tolerance to the transient blood-pressure-raising effects of caffeine, while those who drink less coffee less often may remain sensitive.

Even if coffee drinking contributes to blood pressure elevations in some people, Uiterwaal noted, studies have failed to show that it actually raises the risk of heart disease in healthy people.

He also stressed, however, that this study focused on adults in good general health. The findings do not pertain to people with high blood pressure or other risk factors that increase their odds of heart disease.

SOURCE: American Journal of Clinical Nutrition, March 2007.

Pneumococcal vaccine beyond expectations: study

April 1, 2007 09:56:33 PM PST

A vaccine to fight common bacterial diseases has produced significant and unexpected drops in repeat ear infections and the need for inserted ear tubes in children since its U.S. introduction in 2000, researchers reported on Monday.

"This is exciting news for parents whose children suffer from frequent and painful ear infections," said Katherine Poehling, a pediatrician at Wake Forest University Baptist Medical Center and lead author of the study.

The vaccine "is going beyond what it was supposed to do," she said in an interview.

The vaccination, given initially at 2, 4 and 6 months of age, was designed to combat a number of pneumococcal infections, including ear infections that most children have at least once by the time they turn 2 years old.

But Poehling said the new research shows that the vaccine was also preventing repeat infections, which occur three or four times a year in up to nearly a third of all children, often requiring the insertion of ear tubes to equalize pressure.

The vaccine has also helped adults, she said, by preventing the general spread of disease.

"We have seen declines in the incidence of serious infections such as pneumococcal meningitis in both children and adults, as well as the number of children developing frequent ear infections," she said.

The study, published in the April issue of "Pediatrics," the journal of the American Academy of Pediatrics, looked at data from more than 150,000 children in Tennessee and another 26,409 in upstate New York enrolled in health insurance programs from birth to age 5.

Since the introduction of Pneumococcal Conjugate Vaccine, it found, the proportion of children who developed frequent ear infections and the proportion who received ear tubes declined by 16 percent in Tennessee and 25 percent in New York by age 2.

The vaccine, called PCV7, is marketed by Wyeth under the brand name Prevenar.

Poehling called the results "very exciting" but said public health officials need to keep watch of the situation to make sure pneumococcal strains not included in the vaccine do not become a problem.

Pediatricians urge HIV treatment changes

April 1, 2007 09:18:27 PM PST

The American Academy of Pediatrics says more child-friendly HIV drugs are needed, including smaller pills and three-in-one tablets for kids, to help address a crisis affecting more than 2 million youngsters globally.

In a new policy statement endorsed by 19 international groups including the World Health Organization, the academy outlines barriers and solutions to an issue that is critical in developing regions.

In parts of Africa, AIDS kills about half of HIV-infected children before they reach the age of 2, said Dr. Peter Havens, chairman of an academy AIDS committee. By contrast, about 98 percent of HIV-infected U.S. children are expected to live to adulthood and have nearly normal life spans, thanks to readily available virus-fighting drugs, Havens said.

Some HIV drugs come as bottled liquids that require refrigeration. That poses a problem in rural countries, where some families travel for days by foot to get several months' supply of bottled medicine that weighs as much as the infected child, said Havens, an infectious disease specialist at the Medical College of Wisconsin.

Pills pose a separate problem. Caregivers sometimes break or crush adult-dose tablets to give youngsters smaller amounts, but that results in inexact and inappropriate doses, the policy statement says.

"We hope that this outline ... will give some guidance to the pharmaceutical industry about where it might be best for them to put some of their energies," Havens said.

The statement also is designed to raise awareness among policymakers, he said, noting that two federal measures encouraging research and development of medicines for children are up for reauthorization this year.

"It's important for lawmakers to know this issue is important," Havens said.

The statement was prepared for release Monday in April's Pediatrics, the academy's monthly medical journal.

While much attention has been focused on AIDS in Africa, limited access to HIV medicine and treatment is also an issue in Eastern Europe, "where the number of newly infected infants is still high," said Dr. Carlo Giaquinto of the Pediatric European Network for Treatment of AIDS, whose group is among those that have endorsed the academy's statement.

According to a United Nations/WHO report, 1.7 million people were living with AIDS in Eastern Europe and Central Asia in 2006, a 20-fold increase in less than a decade. Only 13 percent of people in those regions who needed treatment were receiving virus-fighting drugs last year, the UN/WHO report said.

By contrast, there were about 438,000 U.S. AIDS patients in 2005, nearly 4,000 of them under age 13, according to the federal Centers for Disease Control and Prevention.

Lack of pediatric drugs and clinical expertise is a problem in some Eastern European countries, as is a "low commitment of health care authorities in implementing treatment of HIV infected children," Giaquinto said.

There are some HIV drugs designed for children, but not nearly as many as there are for adults, Havens said. As of September, 13 virus-fighting HIV drugs were approved by the FDA for use in children, compared with 22 for adults.

There are no three-in-one HIV drugs approved by the FDA for children, an agency representative said.

Many pediatric HIV drugs are in liquid form or chalky-tasting powders that children reject, Havens said.

Among the newest HIV medicines for children are mini-pills developed by Cipla Pharmaceuticals, an Indian drug maker. The pills, called Pedimune, combine three key virus-fighting medicines ? nevirapine, stavudine and lamivudine ? in doses for infants and older children. They are being studied in African children.

Also, Illinois-based Abbott Laboratories is seeking FDA approval for a new pill version of its Kaletra liquid medicine for children, which combines the virus-fighting drugs lopinavir and ritonavir.

The new tablet is being developed in part to eliminate the need for refrigeration, said Abbott spokeswoman Laureen Cassidy.

AIDS researcher Diana Gibb of the United Kingdom's Medical Research Council praised the academy's report and industry efforts to address the problem, but added: "There is still a way to go and in particular, fast track licensing of new formulations of new and older drugs for children."

Researchers find genetic links to prostate cancer

April 1, 2007 10:02:11 AM PST

Scientists have identified several genetic risk factors for prostate cancer, shedding new light on the cause of a leading worldwide cancer killer among men that hits U.S. blacks especially hard.

"The importance of it is that this is the first real evidence of the genetic basis of prostate cancer," said Dr. Brian Henderson, dean of the Keck School of Medicine at the University of Southern California and one of the researchers of the study released on Sunday.

"It gives us the first real insight we've had into the cause of this disease and how we might do something about it," Henderson added.

The researchers described seven genetic risk factors -- DNA sequences present in some people but not others -- bunched in a relatively small region of one of the human chromosomes, chromosome 8, that reliably predicted one's probability of developing prostate cancer.

Five were newly discovered and two confirmed earlier findings.

The prostate, about the size of a walnut, is a gland below a man's bladder that produces fluid for semen. According to the American Cancer Society, prostate cancer is the second leading cause of cancer deaths in men, behind lung cancer.

Pinpointing these genetic risk factors could be an important step toward helping explain the higher prevalence in U.S. blacks compared to whites, the researchers said.

Black men are twice as likely to die of the disease, and nearly all of the risk factors were seen most frequently in blacks involved in the study.

Henderson said the disease's greater prevalence among blacks had hinted at some sort of a genetic basis for it.

The findings also could lead to ways to sort out who is at highest risk by finding if a man has one of the genetic risk factors, and for early diagnosis of the disease, the researchers said.

Prostate cancer death rates are falling in part because screening is allowing it to be found earlier when it is more treatable.

'GENETIC BASIS'

"We do believe there is a genetic basis. Of course, it's not all genetic. There are also going to be other lifestyle and environmental factors as well," said Christopher Haiman, a USC preventive medicine professor.

"But our findings here in this study suggest that a large fraction of the disparity between African Americans and other populations could be due to genetic variation in this region," Haiman said.

About two-thirds of cases are in men over age 65. The American Cancer Society said men who eat a lot of red meat or high-fat dairy products appear to have higher risk.

The three teams of researchers -- one led by scientists at Harvard University and USC, one by Icelandic company deCODE genetics Inc. and one by the National Cancer Institute, part of the U.S. National Institutes of Health -- presented their findings in the journal Nature Genetics.

The researchers examined genetic information on thousands of men with and without prostate cancer.

Harvard geneticist David Reich said that until last year, when deCODE published narrower earlier findings, there had been no confirmed genetic risk factors for prostate cancer.

"I think it's likely there are other genetic risk factors either in this section of the genome or elsewhere that we and others have not yet identified," Reich said.

"It's only the beginning of the story," Reich added.

Haiman said the researchers do not yet fully understand the biological mechanism through which the genetic variants influence risk for prostate cancer.

 

 

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