 1 EMBRYO, 2 MOMS
British scientists graft third-party mitochondria into a human embryo
Germinal cells can become embryonic stem cells
WASHINGTON
Primordial germinal cells, which are precursors to spermatozoids, apparently have the capacity of turning into embryonic stem cells, according to a recent study. Researcher from the Georgetown school of medicine and a Washington-based regional transplant consortium have obtained these primordial germinal cells shortly after donors' deaths.
These cells known as CGPM were separated using a process that involves enzymes. When the CGPM cells were placed in human embryonic stem-cell cultures, they formed colonies that had characteristics similar to stem cells, according to Drs. Martin Dym and Nady Golestaneh, the main authors of the study presented at a conference of the American Society for Cell Biology.
When these colonies of stem cells were allowed to grow and multiply, they displayed characteristics similar to somite entoblast and ectoblast cells found in an embryo. This has led the researchers to believe that primordial germinal cells have a great potential for organ-regeneration therapies.
Dym pointed out that one could imagine a day when men could be cured from various diseases through testicular biopsy.
African scientists sequence TB genome
JOHANNESBURG
South African scientists announced a major breakthrough in the fight against a highly deadly strain of drug-resistant tuberculosis. Using technology bought from the United States for US$750,000, a group of scientists working for a government-sponsored research center decoded and sequenced the strain.
"We have taken a sample of [extremely drug-resistant (XDR)] TB from a Kwazulu-Natal patient and sequenced the entire genome of the strain of TB," said Carl Montague, the health-portfolio manager of Lifelab which funds the National Genomics Platform. "[It] took us just over a week, using other technology it would have taken up to a year," he said.
It is hoped the breakthrough will lead better diagnosis of the strain and understanding of the mechanisms involved in its resistance to drugs.
"A bacterium is a fairly simple organism. By looking at mutations between the drug-resistant form and drug-sensitive form we are able to see differences and from that be able to look at biological mechanisms, [such as] which genes mutated and how can we use the knowledge to develop better diagnostics," Montague said.
XDR-TB was first discovered in 2006 in Kwazulu-Natal, one of the areas worst hit by AIDS in South Africa.
Three hundred people are known to have contracted it, 188 of whom died, said Lifelab chief executive Blessed Okole, adding the number of cases "may be the absolute minimum." In one situation, all but one of a group of 53 people with the strain died within 25 days of diagnosis.
"We are a significant way from finding a treatment. We do hope to have better diagnostic tools within a year or two. This is the very first step towards a better drug," said James Sakwa, manager of the national genomics platform.
He said the technology imported from the US was able to generate 100 million base pairs of DNA sequence per experiment, meaning massive amounts of information are generated in a very short period of time. The strain of TB was fully sequenced more than 20 times, so that mutations could be distinguished from sequencing errors. The sequence is now busy being analyzed and scientists hope to use it to develop a rapid test to diagnose TB.
Using this technology "we can design drugs that are more effective and better drugs that have already been developed and approved," said Sakwa. Finding an effective drug could take up to 10 years, but the technology could prove useful in probing other drug-resistant diseases such as HIV. "We are going to use it for HIV drug resistance, and we already have a project in line with that," said Okole.
Psoriasis, lupus linked to genes
PARIS
Scientists have identified genes linked to psoriasis and lupus, diseases triggered by immune responses that cause painful inflammation. Knowing that a gene called beta-defensin can trigger skin inflammation in response to infections, a team led by John Armour, a researcher at the University of Nottingham in Britain, decided to find out if people with extra copies of the gene might be more prone to developing psoriasis.
The hunch proved to be right on target. In two separate groups examined, one in the Netherlands and the other in Germany, psoriasis sufferers had significantly more copies of the suspect gene than individuals not troubled by the skin disease.
Many diseases originate from both genetic and environmental factors, and even when genes do play a dominant role, there can be more than one culprit, making it very difficult to determine the root cause. But linking a particular genetic variation to an illness is a key step, and can give researchers leads for new treatments, and possibly even a cure.
Lupus is a far less common disease that makes the body's immune system turn against itself, causing swelling and pain of the skin, joints, and various internal organs. Symptoms are generally mild, but in extreme cases can be life-threatening. More than 90 percent of people with lupus are women, especially during child-bearing years, between 15 and 45. Like psoriasis, the exact cause of lupus is unknown.
A team of researchers in Britain and the United States led by Timothy Vyse of Imperial College in London showed that individuals with a particular genetic variation near a gene called TNFSF4 were at higher risk of developing lupus. In a group of nearly 500 affected families in Britain, along with a smaller sampling in the US, the researchers found that this set of genetic variants seemed to boost the expression of TNFSF4 in blood lymphocytes in lupus sufferers.
Both studies were published online in Nature Genetics.
Stem-cell treatment could work in a decade
TOKYO
Stem-cell technologies could be used to cure diseases and heal injuries within 10 years, a Japanese scientist who recently broke new ground in the field said. Prof. Shinya Yamanaka of Kyoto University, whose team reported in November they reprogrammed human skin cells to be indistinguishable from stem cells taken from human embryos, said the new technology is so simple that many laboratories are competing to make further breakthroughs.
Yamanaka said it was a matter of time before such stem-cell technology was used in hospitals. Said Yamanaka: "I can tell for some patients and for some diseases it may be not, like, 10 years, but for some diseases I can imagine it can take longer than 10 years. That depends on diseases and injuries. There's no single answer."
Stem cells are primitive cells that eventually turn into any of the 220 different types of cells in the human body. They offer enormous potential for curing and treating disease because it is hoped they can replace damaged or diseased cells, tissues, and organs.
The research by Yamanaka's team, who worked alongside US researchers led by James Thomson of the University of Wisconsin at Madison, was praised by the Roman Catholic Church and other critics of embryo research.
The research has since accelerated. Yamanaka said that up to five laboratories in the United States and several in Japan have since also produced stem cells from human skin, known as pluripotent stem cells, or iPS cells.
"This is because technology is very simple," he said. "All you need is a basic technology, cell biology, you don't need special technology or equipment."
Yamanaka said having lots of rivals in his research area has caused him a lot of stress but that he believes it speeds up the process because of the competition. "So I think it's very good for patients who are waiting" for treatment, he said.
New light on human differences
WASHINGTON
US researchers have discovered that individual differences in humans may have more to do with rearranged chunks of DNA rather than specific gene mutations. The findings, which showed as many as 1,300 structural variations between two women of different ethnic descent, could shed light on new ways to combat disease, said researchers at Yale University.
"The focus for identifying genetic differences has traditionally been on point mutations or SNPs-changes in single bases in individual genes," said Michael Snyder, senior author of the study published in Science Express. "Our study shows that a considerably greater amount of variation between individuals is due to rearrangement of big chunks of DNA."
Researchers used a new method called paired-end mapping to examine structural variants between one female of African descent and one of European descent.
The approach involved breaking up the "genome DNA into manageable-sized pieces about 3,000 bases long," after which point scientists "tagged and rescued the paired ends of the fragments, and then analyzed their sequence with a high-throughput, rapid-sequencing method developed by 454 Life Sciences," the study said.
"Previous work, based on point mutations estimated that there is a 0.1-percent difference between individuals, while this work points to a level of variation between two- and five-times higher," Snyder said.
"We also found 'hot spots'-particular regions where there is a lot of variation," said Yale researcher and coauthor Jan Korbel. "While these regions may be still actively undergoing evolution, they are often regions associated with genetic disorder and disease."
The authors said that scientists may have to alter their approach when examining gene variation in the hunt for disease because components of the human genome "may be more variable, and possibly more flexible, than previously thought."
Human embryo with three parents created
LONDON
Scientists in Britain claimed a first, saying they have created a human embryo using DNA from one man and two women, which they say could help provide treatment for genetic diseases.
Researchers from Newcastle University in northeast England used 10 embryos that were unsuitable for in vitro fertilization (IVF), and replaced faulty mitochondria cells from the mother with undamaged cells from a female donor.
The research was disclosed before the House of Lords but has not yet been published officially in scientific journals, the university said.
The embryos were developed for five days and the transplant on one of them was deemed a success. Mitochondria play a vital role in the body's energy supply. However, if they are damaged they can cause a series of serious neuromuscular diseases, liver failure, blindness, deafness, or strokes.
"The research aims to tackle and prevent a group of relatively uncommon but really severe diseases which affect the nervous system and muscles," said Prof. Patrick Chinnery, a Newcastle University neurogenetic expert. "Ultimately in many ... cases they are fatal and there is no treatment. The aim is to develop ways of preventing them from being passed on from the mother to her offspring."
In five to 10 years' time, transplanting "good" mitochondria could be done within days of a routine IVF, he said. The baby would only inherit the mother and father's characteristics, as the transplanted mitochondria from the donor would not have any effect on the child's personality or appearance, the scientists said.
Josephine Quintavelle, of the prolife group Comment on Reproductive Ethics, said: "We should not be messing around with the building blocks of life. To experiment on a human child in this way is absolutely unforgivable."
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