Genetic Variant Predicts Heart Disease Risk

By Apoorva Mandavilli

Testing for a genetic variation could predict the likelihood that a patient will respond well to certain statins. But some researchers say it's too soon to use the variation to determine treatment.

Researchers from Celera reported yesterday in the Journal of the American College of Cardiology that a single substitution in the sequence of a gene called KIF6 makes people both more susceptible to heart attacks and more responsive to certain drugs that lower cholesterol. Though there is no known biological explanation linking the variation to heart disease, the study found that it increases the risk of heart attacks and strokes by 55 percent.

Celera, the company best known for sequencing the human genome, examined 35 single-nucleotide polymorphisms (SNPs) in 30,000 patients. Of those, "KIF6 is by far the most significant," says Thomas J. White, chief scientific officer at Celera. In fact, nearly 60 percent of the study population was found to carry the KIF6 variant. (According to the study, these findings take into account other factors, such as smoking, high blood pressure, and cholesterol levels.)

The researchers also found that carriers of the KIF6 variant responded better to the cholesterol-lowering drugs pravastatin (Pravachol) and atorvastatin (Lipitor). For example, among patients with the genetic variation, those who took pravastatin were 37 percent less likely to experience a heart attack than those who took the placebo. Those without the genetic variation who took the drug were only 14 percent less likely to experience a heart attack than those who took the placebo. Statins are big sellers for the pharmaceutical industry. In 2006, Lipitor, the world's best-selling drug, brought in $13 billion in global sales.

"This is one of the first studies to show an interaction with therapy" and genotype, says Marc Sabatine, professor of medicine at Harvard Medical School and a coauthor on one of the papers. "That is very exciting to see."

Surprisingly, the researchers found that KIF6 doesn't appear to work by lowering levels of LDL or "bad" cholesterol, the standard by which drugs used to prevent heart attacks are normally measured. White says that KIF6 may instead act by stabilizing "vulnerable plaques," which are particularly prone to triggering heart attacks.

Celera is developing a diagnostic that would test for the KIF6 variant and expects to launch it in a few months.

But some experts caution that it may be premature to introduce such diagnostic tests before there is further confirmation of KIF6's role in heart disease.

"Even if there are beneficial results, the standard should be that you need to document that knowing the genetic information is clinically useful," says Sekar Kathiresan, director of preventive cardiology at Massachusetts General Hospital.

Coronary heart disease caused one of every five deaths in the United States in 2006, so scientists have for quite some time been on the hunt for genes linked to heart attacks.

Rapid advances in technology have made that task much easier. At the same time, many of the genetic links to heart disease identified so far haven't held up on further analysis. At present, the only credible link is to a variant of the gene 9p21, identified last year by the Icelandic company deCODE Genetics, says Kathiresan. DeCODE offers a $200 diagnostic test for the 9p21 variant. (See "Gene Variant Linked to Heart Disease.")

A second gene, PCSK9, also looks promising, Kathiresan adds. "Nearly everything else is in the realm of 'possible but not definite.'"

It's good that KIF6 has been identified as a potential risk factor in several different studies, Kathiresan says. In each of the studies, he notes, there is less than a one-in-20 probability that the finding is a result of chance, which is generally considered an acceptable threshold for statistical significance.

But because of the high possibility of false positives, the threshold for genome-wide association studies should be much higher, on the order of one in 20 million, Kathiresan says. Both the 9p21 and the PCSK9 pass that test, he says.

"The key issue here is we don't know if these [KIF6 studies] are real results," Kathiresan says. "You need to show that it is clinically useful, and they have not crossed that threshold."

From here

Sel Penyebab Leukemia Ditemukan

Selasa, 29 Januari 2008 | 13:28 WIB

TEMPO Interaktif, Oxford:
Tim peneliti menemukan bahwa kedua anak kembar tersebut memiliki sel tunas abnormal praleukemia dalam darah mereka. Sel itu bisa "tidur" dalam sumsum tulang atau berkembang menjadi sel tunas leukemia. Hasil ini dikonfirmasi oleh eksperimen yang menggunakan sel tali pusar manusia.

"Penelitian ini berarti kami dapat mengetes apakah penanganan leukemia lymphoblastic akut pada anak bisa dikaitkan dengan menghilangnya dan berkembangnya sel tunas leukemia," kata Profesor Tariq Enver dari Unit Hematologi Molekuler Universitas Oxford, yang memimpin penelitian tersebut. "Mulai saat ini, upaya penyembuhan bisa difokuskan pada upaya membidik sel tunas praleukemia dan sel tunas kanker dengan obat yang ada atau yang akan kita kembangkan."

Upaya penyembuhan yang terfokus, menurut Tariq, bisa menghindari efek samping pengobatan kanker kemoterapi yang menyakitkan dan terkadang justru membahayakan kondisi tubuh pasien. Hal ini sangat penting karena terbukti, Olivia, salah satu anak kembar yang terkena leukemia, mengalami kebutaan di sebelah matanya akibat infeksi yang tidak bisa dilawan tubuhnya saat kemoterapi.

Para ilmuwan telah melacak kemungkinan sel tunas prakanker itu akibat fusi abnormal dari dua gen yang terjadi selama kehamilan ibu. Fusi ini menghasilkan protein hibrida, sebuah "kesalahan" genetik yang terjadi secara acak dan menyebabkan sel menjadi terjangkit leukemia. Gen yang diambil dari si kembar lantas ditransplantasikan ke tikus laboratorium yang mengkonfirmasi adanya hubungan langsung antara malfungsi genetik dari sel tunas tersebut dan leukemia.

Lembaga donor Inggris yang membiayai penelitian itu, Leukemia Research and the Medical Research Council, dan Rumah Sakit Great Ormond Street menyatakan sangat gembira atas penemuan itu dan berharap penelitian dilanjutkan ke upaya mencegah dan mengobati penyakit tersebut.

AMAL IHSAN | SCIENCEDAILY

from here

Gene Therapy for Chronic Pain

By Jocelyn Rice

A new kind of gene therapy could bring relief to patients suffering from chronic pain while bypassing many of the debilitating side effects associated with traditional painkillers.

Researchers at Mount Sinai School of Medicine injected a virus carrying the gene for an endogenous opioid--a chemical naturally produced by the body that has the same effect as opiate painkillers such as morphine--directly into the spinal fluid of rats. The injections were targeted to regions of the spinal cord called the dorsal root ganglia, which act as a "pain gate" by intercepting pain signals from the body on their way to the brain. "You can stop pain transmission at the spinal level so that pain impulses never reach the brain," says project leader Andreas Beutler, an assistant professor of hematology and medical oncology at Mount Sinai.

The injection technique is equivalent to a spinal tap, a routine procedure that can be performed quickly at a patient's bedside without general anesthesia.

Because it targets the spinal cord directly, this technique limits the opiate-like substance, and hence any side effects, to a contained area. Normally, when opiate drugs are administered orally or by injection, their effects are spread throughout the body and brain, where they cause unwanted side effects such as constipation, nausea, sedation, and decreased mental acuity.

Side effects are a major hurdle in treating chronic pain, which costs the United States around $100 billion annually in treatment and lost wages. While opiate drugs can be very effective, the doses required to successfully control pain are often too high for the patient to tolerate.

"The side effects can be as bad as the pain," says Doris Cope, director of the University of Pittsburgh Medical Center's Pain Medicine Program. Achieving the benefits of opiate treatment without their accompanying side effects, Cope says, would be a "huge step forward."

Beutler hopes to do just that. "Our strategy was to harness the strength of opioids but target it to the pain gate, and thereby create pain relief without the side effects that you always get when you have systemic distribution of opioids," he says.

Several groups have previously attempted to administer gene therapy for pain through spinal injections, but they failed to achieve powerful, long-lasting pain relief. The new technique produced results that lasted as long as three months from a single injection, and unpublished follow-up studies suggest that the effect could persist for a year or more.

Beutler credits his team's success to the development of an improved virus for delivering the gene. The team uses a specially adapted version of adeno-associated virus, or AAV--a tiny virus whose genome is an unpaired strand of DNA. All the virus's own genes are removed, and the human endogenous opioid gene is inserted in their place. Beutler's team also mixed and matched components from various naturally occurring AAV strains and modified the genome into a double-stranded form. These tweaks likely allow the virus to infect nerve cells more easily and stick around longer.

Once the virus is injected into the spinal fluid and makes its way into the nerve cells of the pain gate, it uses the host cells' machinery to churn out the opioid protein--which then goes to work blocking pain signals on their way to the brain. Normally, the gene is rarely activated. But the version used for therapy has no such limitations because the gene carried by the AAV has been modified to continuously produce the opioid chemical.

Cope says that using endogenous opioids is inherently superior to injecting synthetic opiate drugs directly into the spinal fluid, an approach that requires the installation of a pump in order to deliver the drugs over a long time period. "It's kind of a holy grail," she says. "If the body's own system for pain control were activated by genetic expression, that would be superior to an artificial medication."

In Beutler's study, which was published this week in PNAS, rats were surgically modified to have a stronger than usual response to pressure on their paws, mimicking the effects of so-called neuropathic pain. The gene-therapy treatment effectively restored the rats to a normal level of pain sensitivity. The team also tested a nonopioid gene, which produced comparable pain relief through an entirely different mechanism. But while the opioid gene's effects will likely extend to humans, who respond to opiates the same way rats do, the nonopioid's effects may be rat specific.

The Stockholm-based company Diamyd Medical has been developing a different approach to gene therapy for chronic pain that also bypasses the side effects of standard pain treatment. The approach uses a deactivated version of herpes simplex virus (HSV). HSV can be administered straight through the skin as it naturally finds and infects peripheral nerves and travels to the spinal cord on its own. Darren Wolfe of Diamyd says that this method is superior to spinal injection because it's safer and easier, and it can be administered repeatedly.

Because of these considerations, the HSV method may be preferable for treating localized pain. However, when chronic pain involves multiple areas of the body--as it often does with, for example, metastasized cancers--going straight to the pain gate could work more efficiently.

While both of these methods have proved effective in animal models of pain, their efficacy in human patients remains to be shown. Diamyd recently applied to the FDA to begin phase I clinical trials, and Beutler estimates that his approach could be tested on humans in as few as three years.

From here

Gadis Australia Pasien Pertama Dunia yang Berubah Golongan Darah

Canberra (ANTARA News) - Seorang gadis remaja Australia --Demi-Lee Brennan-- menjadi pasien pertama yang mengubah golongan darahnya dan menerima sistem kekebalan dari donor organnya.

Brennan yang kini berusia 15 tahun menerima transplantasi organ hati pada saat usianya 9 tahun karena organ harinya tidak berfungsi.

"Hal itu adalah kesempatan kedua saya untuk dapat bertahan hidup," kata Brennan kepada media massa setempat ketika menceriterakan bagaimana tubuhnya berhasil menerima dan beradaptasi bedah transplantasi yang dapat dikatakan "Mukjizat" yang datang dari Tuhan. "Sungguh sulit dipercaya."

Golongan darah Brennan mengalami perubahan dari "O" negatif menjadi "O" positif pada saat ia sakit dan diberikan pengobatan untuk menghindari penolakan terhadap organ hati donor oleh sistem kekebalan tubuhnya.

Sel batang pembuluh darah hatinya yang baru memasuki sumsum tulang belakangnya yang mengubah seluruh sistem kekebalan tubuhnya, berarti si remaja Brennan tak lagi memerlukan obat-obatan anti penolakan tubuh.

Para dokter dari Rumah Sakit Anak Westmead di Sydney mengatakan mereka belum dapat memberikan keterangan kasus Brennan yang mengalami kesembuhan, seperti yang mereka sampaikan dalam majalah kedokteran, The New England Journal of Medicine.

"Terus terang kami belum menemukan penjelasan untuk hal itu," kata Michel Stormon seorang ahli hepatologi pediatri seperti dikutip Reuters.

Sturat Dorrney, mantan kepala bagian unit transplantasi di rumah sakit itu mengatakan, kasus Brennan dapat membuka jalan bagi terapi transplantasi organ, karena biasanya sistem kekebalan tubuh pasien penerima menyerang transplantasi jaringan di donor.

"Kini kami harus kembali mengkaji ulang semua tahapan yang terjadi pada Demi-Lee dan melihat mengapa hal itu dapat terjadi dan kalau-kalau dapat melakukan pengulangan kembali," kata Dorney.

"Kami berpikir hal itu mungkin karena kami menggunakan organ hati dari seseorang yang usianya masih muda dan Demi-Lee memiliki sel darah putih dalam jumlah rendah mungkin karena dua faktor itulahyang menjadi alasan," katanya kepada harian Daily Telegraph.

Penolakan tubuh umumnya ditangani dengan kombinasi obat-obatan walaupun penolakan kronik tidak terjadi dua arah (bolak-balik).

Hanya tujuh dalam 10 operasi transplantasi di Australia yang berhasil setelah lima tahun berselang yang dikarenakan oleh penolakan tubuh di pasien. (*)

from here

Pil KB Cegah Kanker Indung Telur

Beijing (ANTARA News) - Pil KB dapat berbuat lebih dari sekedar mencegah kehamilan, pil tersebut juga dapat melindungi perempuan dari kanker indung telur selama lebih dari 30 tahun atau lebih setelah mereka mengkonsumsinya, demikian hasil penelitian di Inggris yang disiarkan pekan ini.

Makin lama perempuan mengkonsumsi pil itu, makin rendah resiko mereka terserang penyakit itu, yang lebih umum menyerang setelah perempuan berusia 50 tahun, tulis para peneliti tersebut di jurnal "Lancet".

Perempuan yang mengkonsumsi pil itu selama 15 tahun mengurangi resiko mereka terserang penyakit tersebut separuhnya, kata para peneliti itu.

Di seluruh dunia, pil tersebut sudah membantu 200.000 perempuan dari serangan kanker indung telur dan telah mencegah 100.000 kematian akibat penyakit itu, kata Valerie Beral dari University of Oxford dan rekannya dalam laporan mereka.

"Ketika anda berusia 60 tahun, ada manfaatnya jika anda mengkonsumsinya lima tahun atau 10 tahun saat anda berusia 20-an tahun," kata Beral dalam suatu wawancara telefon. "Makin lama anda mengkonsumsinya, makin baik bagi anda tatkala resiko kanker indung telur tinggi."

Sebanyak 300 juta perempuan telah menggunakan pil KB sejak pil itu diperkenalkan pada awal 1060-an. Ratusan kajian telah meneliti keamanannya, sebagian menunjukkan manfaat dan yang lain memperlihatkan peningkatan resiko kanker payudara dan kanker leher rahim.

Beral dan rekannya mengatakan penelitian mereka, yang menganalisis 45 kajian kanker indung telur di 21 negara, memperlihatkan bahwa manfaat pil tersebut lebih besar dari resikonya. Kanker

Kanker indung telur sangat mematikan karena perempuan seringkali mengalami gejala ringan atau tak menghadapi gejala sama sekali hingga penyakit itu telah berkembang.

Resiko kanker payudara, yang juga mengakibatkan stroke dan pembekuan darah, jauh lebih kecil dan hanya ada saat perempuan mengkonsumsi pil tersebut dan tak lama setelah mereka berhenti, kata Beral seperti dikutip Xinhuanet.

Mengkonsumsi pil itu selama 10 tahun mengurangi resiko kanker indung telur sebelum usia 75 tahun dari 12 per 1.000 perempuan jadi 8 per 1.000. Pil tersebut juga mengurangi resiko kematian akibat penyakit itu dari 7 per 1.000 perempuan jadi 5 per 1.000 sebelum usia 75 tahun, demikian temuan studi tersebut.

Lebih dari 100 juta perempuan sekarang mengkonsumsi pil tersebut, jadi akhirnya itu akan mencegah lebih dari 30.000 kasus kanker indung telur setiap tahun selama beberapa dasawarsa ke depan, tulis para peneliti tersebut. (*)

Copyright © 2008 ANTARA

Pengobatan Kanker Juga Bantu Obati Osteoporosis

Washington (ANTARA News) - Obat yang digunakan untuk mengobati kanker tulang sumsum juga dapat membantu mengobati osteoporosis dengan merangsang sel-sel tungkai, kata beberapa peneliti AS, Jumat.

Mereka mendapati bahwa Velcade, yang dibuat oleh Millenium Pharmaceuticals Inc (MLNM.O) untuk mengobati tumor ganda di sumsum tulang, mengaktifkan sel-sel tungkai yang berubah menjadi tulang.

Ujicoba terhadap tikus memperlihatkan membantu mengaktifkan jaringan tulang dan mungkin merupakan pengobatan yang berpotensi bagi osteoporosis, kata satu tim di Massachusetts General Hospital dan Harvard Stem Cell Institute di "Journal of Clinical Investigation".

Ahli sel tungkai di Harvard Dr. David Scadden mengatakan, para ilmuwan telah berharap menemukan cara untuk menggunakan obat guna merangsang sel-sel tungkai, yang merupakan sel pengendali tubuh.

"Terapi sel tungkai seringkali dikira sebagai tindakan memasukkan sel baru ke dalam tubuh, tapi studi ini menunjukkan bahwa pengobatan dapat mengubah sel-sel tungkai yang ada yang terdapat di jaringan tubuh dan bertindak sebagai obat pengaktifan untuk meningkatkan mekanisme perbaikan sendiri tubuh," kata Scadden dalam suatu pernyataan.

"Obat yang mengarahkan sel-sel tak matang untuk menjadi sejenis sel khusus, seperti dalam studi ini, dapat berpotensi sangat bermanfaat," katanya seperti dikutip Reuters.

Velcade, yang secara generika dikenal sebagai "bortezamib", merangsang sel-sel tungkai "mesenchymal", demikian temuan para peneliti tersebut. Sel-sel itu berkembang menjadi zat pembangun-tulang "osteoblast" dan beberapa jenis sel lain termasuk "cartilage", lemak, kulit dan otot.

Ujicoba pada tikus memperlihatkan obat tersebut meningkatkan kegiatan "osteoblast", dan ketika digunakan pada tikus yang menderita osteoporosis, obat itu secara mencolok meningkatkan kepadatan dan susunan tulang.

"Jika paradigma yang terlihat dalam studi ini terbukti benar bagi jaringan lain, kita mungkin memiliki pilihan untuk memperbaiki dan mengaktifkan kembali berbagai tempat yang terpengaruh oleh cedera atau penyakit dengan menggunakan obat --itu akan sangat menggairahkan," kata Scadden. (*)

Copyright © 2008 ANTARA

Mixing Up the Immune System

By Anna Davison

By performing bone-marrow transplants along with kidney transplants, doctors in Boston were better able to trick recipients' immune systems into accepting the new organs as if they were their own.

Even though the patients received donor kidneys that weren't a good match, most of them were successfully weaned off of immune-suppressing drugs about a year after their transplants. Normally, patients have to take the drugs, which can have serious side effects, for the rest of their lives.

"It's groundbreaking work," says John C. Magee, director of the Kidney Transplant Program at the University of Michigan, who was not involved in the study. "They've shown that you can reeducate the immune system."

The technique could be applied to other kinds of transplants and used in the treatment of autoimmune diseases, says Megan Sykes, one of many researchers who carried out the work at Massachusetts General Hospital. Sykes is the associate director of the hospital's Transplantation Biology Research Center.

The team has been working for about 20 years to outsmart the immune system by inducing tolerance to a donor organ. In this study, reported in this week's issue of the New England Journal of Medicine, the scientists transplanted bone marrow along with a mismatched kidney, giving patients a kind of hybrid immune system that blended elements of both the donor and the recipient.

Four out of five patients who received bone-marrow transplants in conjunction with kidney transplants didn't need long-term treatment with immune-suppressing drugs. The technique was not successful for the fifth patient, however: his body rejected the donor kidney. He was given a second--and successful--transplant according to conventional protocol.

Doctors try to match people with similar versions of the genes that play a crucial role in immune reactions to foreign tissue. This genetic region is known as the human leucocyte antigen (HLA) complex. But finding a good match isn't always possible, so doctors often use a mismatched kidney and put the patient on immunosuppressive drugs to reduce the risk of rejection. The patients in the study, whose ages ranged from 22 to 46, were all suffering from advanced kidney disease and were unable to find living donors who were a very good tissue match. They received kidneys from family members who were HLA mismatched.

Before the surgery, the transplant team gave the patients drugs to deplete their bone marrow and suppress their immune response. After receiving new kidneys and then an intravenous infusion of bone marrow from their donors, the patients were kept in a relatively sterile environment to reduce their chance of infection, and to allow the bone marrow to regenerate and produce new immune cells that wouldn't attack the donor kidney.

In the months after their transplants, the patients in the study were treated with immunosuppressive drugs, but four out of five of them were able to discontinue those drugs between 9 and 14 months after surgery, and their new kidneys have been functioning well in the years since.

"I think it's quite exciting," Magee says. "It shows what's possible."

The researchers' approach could make transplants more feasible for people whose immune systems are already compromised by conditions like HIV, according to Yasir Qazi, medical director of the kidney and pancreas transplant program at the University of Southern California. (Qazi was not involved in the work.) Sykes says that the approach could potentially be used to treat autoimmune diseases such as type 1 diabetes. "It could have huge benefits," she says.

Although immunosuppressive drugs have revolutionized transplant medicine, they can increase the risk of cancer and heart disease. "Immunosuppression is great, because it makes kidneys work, but it's bad because it has lots of side effects," Magee says. "Some people say that in many ways, you're trading one disease for another. You still have to take lots of medicine and see a doctor."

The protocol developed by Sykes and her colleagues initially requires heavier drug treatment than that required with the standard kidney-transplant procedure, to allow the recipient's body to accept donated bone marrow as well as a donated kidney. But, she points out, the patient is only on the drugs for a limited time.

From here

Treating Muscular Dystrophy with Stem Cells

Researchers at the University of Texas Southwestern Medical Center (UT Southwestern) have used embryonic stem cells from mice to grow muscle cells. These same cells, injected into mice with a mild form of muscular dystrophy, formed healthy, functional muscle fibers at the site of deteriorating tissue. Scientists say that the research, while still in its early stages, could eventually lead to a cell-based therapy for patients with muscular dystrophy and other muscle-related diseases. The research was recently published in the online edition of Nature Medicine.

According to the Muscular Dystrophy Association, about 250,000 people in the United States have some form of the disease. The most well known, Duchenne muscular dystrophy, is caused by a genetic mutation that disrupts the formation of dystrophin, an important protein involved in the formation of muscle cells. In the absence of dystrophin, muscles are unable to regenerate, and they gradually weaken and waste away. Eventually, the deteriorated area is taken over by fat and connective tissue.

Rita Perlingeiro, assistant professor of developmental biology at UT Southwestern, says that embryonic stem cells may be the key to reversing muscular dystrophy's debilitating effects. The advantage lies in the cells' pluripotency--the ability to transform into any mature cell, be it bone, muscle, or cartilage. However, many researchers have found it difficult to direct every stem cell in a culture to form a specific type of cell. In lab experiments, scientists often end up with a mixture of cells that, when injected into an animal, form large clusters resembling a tumor.

So Perlingeiro and her team set two main goals: to find the right set of cues to convert embryonic stem cells into muscle cells, and to look for ways to isolate muscle cells from the rest of the culture medium, in order to inject a dose of pure muscle cells into a mouse model.

In normal embryologic development, stem cells turn into various tissue and bone, depending on a combination of molecular and genetic signals. In the case of muscle cells, past research has shown that the gene Pax-3 is essential in pointing stem cells down the path of muscle formation. With this knowledge, Perlingeiro and her team grew mouse-derived embryonic stem cells in a culture dish, then genetically manipulated the solution to overexpress Pax-3. They found that, compared with mixtures without Pax-3, a significant number of stem cells exposed to the activated gene formed muscle cells.

However, not all of the cells turned into muscle, and when the team injected the solution into a mouse with a mild form of muscular dystrophy, the mixture caused tumors to form. The team then focused on developing an identification process that would make muscle cells stand out from the rest of the solution. Once again, Perlingeiro looked to basic developmental research and found that, during normal muscle formation in the embryo, stem cells that become very early versions of muscle cells display certain surface molecules, or markers. The team repeated the first phase of its experiment, exposing embryonic stem cells to Pax-3, and looked for the telltale markers indicating muscle cells. The researchers then isolated these cells, creating a solution that consisted solely of muscle cells.

In preparation for injecting the new solution into a mouse model, the team first injected cardiotoxin into the mouse's leg. The effect inhibited the production of dystrophin, causing a weakening of the muscle--a condition resembling muscular dystrophy. Perlingeiro and her colleagues then injected the mouse with the muscle-cell solution. The team then took muscle biopsies and, after immuno-staining, found that, compared with mice that did not receive the solution, treated mice exhibited more dystrophin, indicating healthy muscle regeneration.

To confirm their results, the researchers ran both groups of mice on a treadmill; they found that the mice that received the solution outlasted the group that did not. Perlingeiro went a step further: after sacrificing both animal groups, she and her colleagues extracted every leg muscle, treated or untreated. They then placed each muscle in a bath and tested its strength by exposing it to an electrical impulse. The team found that the stronger contractions came from the muscles treated with the stem-cell-derived solution.

Perlingeiro says that the study's results are encouraging, as she envisions one day providing stem-cell-based therapy for people with muscular dystrophy and other muscle-related diseases. However, there will have to be more follow-up studies before the technique can be applied to humans.

"I have a long to-do list," says Perlingeiro. "We'd like to use the same technique on human embryonic stem cells."

Recently, researchers were able to turn human skin cells into embryonic stem cells, a technique that bypasses the thorny issues currently surrounding use of embryonic stem cells. Perlingeiro says that combining this technique with her muscle-deriving method may one day yield effective, efficient treatment of diseases such as muscular dystrophy.

"If we can reprogram skin cells to become pluripotent, and use Pax-3 to make muscle, then we would be able to make cells from the patient, and we wouldn't face ethical issues or problems of rejection," says Perlingeiro.

Paul Muhlrad, a research program coordinator for the Muscular Dystrophy Association, says that the study's results are a promising step toward effective treatment for muscle-related diseases. "These researchers present a nice proof of principle that embryonic stem cells can be turned into muscle-producing cells in the laboratory and used to deliver healthy muscle to people with Duchenne muscular dystrophy," says Muhlrad. "Of course, these experiments were done with mice. We've yet to see whether they will work in humans, but this study offers us much hope."

from here

How Important Is the Latest Cloning Feat?

Scientists at Stemagen, a small biotechnology company in La Jolla, CA, reported yesterday that they have for the first time generated cloned human blastocysts--early-stage embryos--from adult skin cells. This is the first step in generating stem cell lines matched to individuals, which are crucial for creating new cellular models of disease and potentially important for future tissue replacement therapies. (See "Next Steps for Stem Cells" and "The Real Stem Cell Hope".) The new findings also confirm that access to fresh eggs from healthy young donors is a key part of successful cloning. Lack of access to human eggs has been the major barrier in the field. (See "Human Therapeutic Cloning at a Standstill".)

Cloned blastocysts have been generated before, but from embryonic stem cells rather than from adult cells. Scientists theorize that embryonic stem cells are easier to turn into blastocysts because of their earlier developmental stage.

Experts in the field have had a mixed reaction to the new work. "It's a nice achievement, but in my view, they haven't crossed the bar," says Evan Snyder, director of the Stem Cells and Regenerative Medicine Program at the Burnham Institute in La Jolla. "The real test will be, can you generate cell lines that are stable and self-renewing and normal?" Others applaud the confirmation of the feasibility of human cloning. "The fact that it can be done is important," says Jeanne Loring, a stem cell scientist at the Scripps Research Institute in La Jolla. "It wipes away that blot on our scientific integrity," she says, referring to a massive fraud unveiled in 2005 in which South Korean scientist Woo Suk Hwang claimed to have generated stem cell lines from cloned human embryos. (See "Stem Cells Reborn".)

To clone an embryo, a process also called nuclear transfer, scientists first strip an egg of its genetic material. Then they insert DNA from an adult cell, such as a skin cell, into the egg. Through an unknown process, the egg turns back the clock on the adult DNA and begins to develop as a normally fertilized egg would. From the embryo, researchers could theoretically collect a specialized ball of cells that can be coaxed to turn into stem cells. So far, however, no one has successfully performed this feat.

Stemagen, a relatively unknown player in the field, probably owes its success to access to human eggs through a close association with a local fertility clinic. (The company was founded by a fertility specialist at the Reproductive Sciences Center in La Jolla.) "We were able to get access to high-quality oocytes and have them in the incubator within one to two hours," says Andrew French, Stemagen's chief scientific officer.

Egg donors and the intended parents gave eggs in excess of those needed for in vitro fertilization to the Stemagen scientists for research. Regulations in many states prohibit compensation for donated eggs for ethical reasons, a requirement that has slowed other cloning efforts.

Starting with 25 fresh oocytes, French and colleagues generated five blastocysts--five- to six-day-old embryos consisting of 30 to 70 cells. Rather than attempting to generate stem cell lines from the embryos, the researchers sent them to an independent company for genetic confirmation of their results. "They showed we had completely removed the DNA from the egg donor and replaced it with DNA from the skin-cell donor," says French. One blastocyst was confirmed as a clone via two DNA-fingerprinting methods, while genetic analysis of two others indicated the likelihood that they were clones.

The next crucial step will be generating stem cell lines from cloned embryos, which many stem cell scientists speculate will be the most challenging step. "That's likely where Hwang failed," says Synder.

French and colleagues are planning such experiments, with results potentially in the next eight to twelve months. "The quality of our blastocysts improved with each experiment," says French. Based on the success rate of previous attempts to make stem cells from regular embryos, he estimates that Stemagen will be able to generate a stem cell line from between five and ten cloned embryos and report the results in the next year. The company aims to sell or license the lines to pharmaceutical companies and others who would use them to test new drugs or develop new therapies.

While human therapeutic cloning has always been an ethically contentious area of research--partly because it requires the creation and destruction of human embryos--it has recently come under greater fire. After the announcement of new techniques for reprogramming adult cells so that they turn into stem cells without first forming embryos, some opponents called for a halt on embryonic-stem-cell research. (See "Stem Cells without the Embryos".)

However, researchers in the field emphasize the need to pursue all reprogramming techniques. "Even though there are other techniques to reprogram a cell that have gotten a lot of press, we still don't know how those compare with the reprogramming you actually see with nuclear transfer," says Snyder. "My feeling is, if we understand nuclear transfer better, we will be able to do the other kind of reprogramming more efficiently."

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Magnetic Cell Therapy

Stents are expandable stainless-steel scaffolds commonly used to prop open clogged arteries. But inserting a stent can damage an artery's inner lining, and stented arteries may reclose after several months, causing blood clots and possibly heart attacks. Now researchers at the Children's Hospital of Philadelphia have devised a way to use tiny iron-bearing nanoparticles and a magnetic field to direct cells with therapeutic properties to the sites of steel stents. The cells could help repair arterial damage and prevent clotting, among other things.

"Stents have been known to induce severe trauma," says Robert Levy, chair of pediatric cardiology at the Children's Hospital of Philadelphia. "Repairing blood vessels with cell therapy is a very important concept that can be realized with magnetic targeting."

Levy and his colleagues engineered nanoparticles, or tiny spheres, of polylactic acid, a biodegradable polymer used in sutures and other medical applications. The team then loaded each nanoparticle with a small dose of magnetically responsive iron oxide and inserted it into a bovine endothelial cell--a cell found in a blood vessel's inner lining. The bovine cells were genetically altered to express a fluorescent marker, making them easily detectable.

Next, the researchers surgically implanted small metal stents in the carotid arteries of live rats. They injected the rats with a solution of treated endothelial cells and created a steady magnetic field around each rat using two large, external electromagnetic coils. Levy says that the magnetic field he and his colleagues applied was less than a tenth of the strength of the fields generated by conventional MRI machines. After 48 hours, the team created images of the rat using bioluminescence imaging.

The researchers found that the magnetic field caused the cells to migrate to the metal stents under two scenarios: when cells were injected directly into the carotid artery, near the stent location, and when they were injected farther away, in the aortic arch, whence they could have branched out to all areas of the body. In tests that didn't use a magnetic field, the cells migrated throughout the body with little direction.

Magnetically directing cells, particularly endothelial cells, to the sites of metal stents may have a significant therapeutic effect, says Levy. During surgical implantation, stents tend to scrape off endothelial cells, whose normal functions include helping prevent blood clotting. Endothelial cells are also barriers to inflammatory cells. While inflammatory cells normally flock to an injury to help repair it, in the absence of endothelial cells, they build up excessively, creating arterial blockage. In recent years, stents have been engineered to release anticlotting drugs to prevent arteries from reclosing. But such drug-releasing stents have problems of their own, including preventing endothelial cells from regenerating.

"Two years ago, clinicians noticed that patients in significant numbers were having problems with these stents, probably because the endothelium wasn't properly healed," says Levy. "Clotting, myocardial infarctions, and sudden deaths occurred, and this has caused a big uproar over stent usage."

Levy hopes that magnetically directing new endothelial cells to blood vessels may solve many of the problems that stents currently face. His team plans to continue experimenting on rats, using endothelial cells derived from rats instead of cows, to minimize risk of rejection. Now that he has found a way to direct cells to metal stents, Levy is also looking at other potential therapies, including nitric oxide, which is known to relax and dilate blood vessels. He is currently engineering cells to genetically express enzymes that produce nitric oxide, and he will eventually load them with iron-oxide nanoparticles that will drive them to the sites of stents, further opening arteries.

Levy adds that the magnetic-based technique has applications outside of cardiovascular therapy. For example, in treating lung cancer, clinicians often use metal stents to keep airways open. However, a patient's tumor may continue to grow, eventually obstructing the passage despite the stenting. Magnetically targeted therapies could help deliver specific drugs to stent sites to treat tumors, in addition to keeping airways open.

"Metallic implants are also widely used in other areas, like orthopedics, for complex fractures, and correcting spinal curvature, where cell therapies could also be helpful," says Levy. "Steel implants are widely used in medicine, and there are all sorts of situations where applications could be used."

What's more, Levy envisions that such therapies can be applied using conventional MRI machines. The magnetic field generated by MRI cores is an order of magnitude more powerful than the ones Levy used in his experiments, so fewer iron-oxide nanoparticles could produce the same effect.

Robert Langer, Institute Professor at MIT, believes that Levy's technique is a promising step toward directed cell therapies. "They were able to localize more drugs into the targeted areas," he says. "I think it's a neat idea that has a lot of potential."

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Gene Therapy for Alcoholics

Researchers in Chile have succeeded in keeping the drinking habits of alcoholic rats in check using gene therapy. The treatment mimics a natural mutation common in East Asian people, which lowers their tolerance to alcohol, making them less likely to become alcoholics.

According to the National Institutes of Health, 17.6 million people abuse alcohol or are alcohol dependent in the United States alone. If the gene-therapy technique could be applied to humans, scientists say that it may be a valuable addition to the drugs and behavioral approaches currently used to treat alcoholism.

The gene therapy works in a similar way to a drug currently used to treat alcoholics, which is effective but unpopular with patients, many of whom stop taking it.

"It's great when innovative approaches are being used for treatment, because we need them," says George Koob, codirector of the Pearson Center for Alcoholism and Addiction Research, at the Scripps Research Institute. He was not involved in the work in Chile.

The gene therapy, described in the latest issue of the journal Alcohol: Clinical and Experimental Research, curbed the activity in the liver of an enzyme--aldehyde dehydrogenase--that plays a major role in metabolizing alcohol. Nearly a third of East Asians have a natural genetic mutation that has the same effect, so when they drink, their faces turn red, their hearts pound, and they feel sick--all good incentives to go easy on alcohol.

The gene therapy tested by Yedy Israel, a professor of pharmacological and toxicological chemistry at the University of Chile, and his colleagues triggers the same unpleasant response to alcohol in rats.

"It's a new way of doing an old thing," Koob says. "I think it's very clever and very interesting."

The researchers in Chile started with rats bred for their alcoholic tendencies and offered them unlimited quantities of diluted ethanol--the equivalent of higher-alcohol premium beer--for two months to make them even more dependent. The researchers then cut off the animals' access to alcohol and injected some of them with a virus containing a gene that inhibits aldehyde dehydrogenase.

Three days later, the researchers implemented a month of daily "happy hours," letting the rats drink as much as they wanted. In an hour, each of the animals put away the equivalent, in human terms, of about seven premium beers--10 times more alcohol than what was put away by alcoholic animals that hadn't been through the two-month dependency regimen.

During the first happy hour, rats that were given gene therapy "didn't realize they were going to feel bad, and they drank a tremendous amount," Israel says. Afterward, "the animals clearly didn't look comfortable." Those rats then markedly reduced their alcohol consumption on subsequent days. Over the course of the happy hours, they drank half as much, on average, as the untreated animals. The effect lasted throughout the monthlong study.

Israel and his colleagues are now working on ways of delivering gene therapies that last for years or even a lifetime, in the hope of developing long-lasting treatments for alcoholism. Most of the medications available now need to be taken at least once a day, and many alcoholics don't comply with the routine. A longer-lasting drug is likely to be more successful, Israel says.

Two of the three existing drug treatments approved for alcoholism by the Food and Drug Administration--naltrexone and acamprosate--limit the craving for alcohol. The other treatment--disulfiram--works in a similar way to Israel's gene therapy: by making patients sick if they drink. The trace of alcohol in mouthwash is enough to trigger a reaction, and most alcoholics "really dislike this medication," says Carolyn Drazinic, an assistant professor in the Department of Psychiatry and the Department of Genetics and Developmental Biology at the University of Connecticut. She was not involved in the gene-therapy research.

"All of these drugs," Israel says, "really require patients' compliance with their medication, which is rare."

Drazinic says, though, that a lifelong treatment that makes someone sick after a whisper of alcohol might not have too many takers. "There may be a lot of patients who would refuse something like this, if they've ever experienced a disulfiram reaction," she says. Drazinic believes that a more popular option might be a treatment that doesn't last a lifetime, but long enough not to be a daily hassle.

That, Koob says, would be better than "someone sitting there with a baseball bat telling you to take your Antabuse [the trade name for disulfiram] with your Wheaties."

Robert Swift, a professor of psychiatry and human behavior and the associate director of

Brown University's Center for Alcohol and Addiction Studies, says that the gene-therapy approach "is a very interesting technique, but it's not ready for prime time."

"There are a lot of medications that reduce drinking in animals but may not be as effective in humans," he says. "The question is, can you really make enough difference in the enzymes that humans will reduce their drinking?"

Gene therapy is risky, and if it's ever used to treat alcoholism in humans, it should be a last-ditch option for hardcore alcoholics, Swift says. However, those patients are often suffering from liver damage, and "if someone's got damaged liver cells, you've got a greater risk of complications from genetic treatment."

Israel's gene-therapy approach is "perfectly logical," says Raymond White, director of the University of California, San Francisco's Ernest Gallo Clinic and Research Center, where scientists study the biological basis of alcohol and substance abuse. But White adds that he'd be quite surprised "if this became a real therapy."

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A New Treatment for Alzheimer's?

By Anna Davison

A drug commonly used to treat arthritis caused a dramatic and rapid improvement in patients with Alzheimer's disease, according to physicians in California. However, scientists and others not involved in the work worry that the report, which was based on trials in a few patients and hasn't been independently confirmed, may offer little more than false hope for Alzheimer's sufferers and their families.

Alzheimer's patients injected with the anti-inflammatory drug etanercept--marketed as Enbrel--showed dramatic improvements in their functioning within minutes, according to Edward Tobinick, director of the Institute for Neurological Research, a private medical facility in Los Angeles where the patients were treated, and an assistant clinical professor of medicine at the University of California, Los Angeles.

"The patients improve literally before your eyes," says Tobinick, who began using etanercept in Alzheimer's patients three years ago. He uses an unconventional method to administer the drug; he injects it near patients' spines. In 2006, he reported success with weekly treatments given to 15 people over the course of six months. In a case study in the latest issue of the Journal of Neuroinflammation, Tobinick and Hyman Gross, who practices in Santa Monica, describe how a patient improved within 10 minutes of treatment, and how cognitive tests performed two hours after the treatment showed a marked improvement over tests given before the injection. Tobinick says that the rapid improvement is typical in patients he has injected with etanercept. He treats them weekly, or, in some cases, less often.

"In each case, the person was more alert, calm, attentive, and they stayed on track," says Sue Griffin, director of research at the Donald W. Reynolds Institute on Aging at the University of Arkansas for Medical Sciences, who watched Tobinick treat several patients. Griffin says that she was skeptical when she first heard about Tobinick's approach, but having witnessed the effect firsthand, she says, "It was just completely amazing, like nothing I'd ever seen for an Alzheimer's person."

Minutes before the treatment, the patient in the case study couldn't recall the year or which state he was in. Ten minutes after the injection, he answered these questions correctly. As part of a cognitive assessment performed the day before the treatment, the patient was asked to draw a clock face showing a certain time. He sketched a square. Two hours after the injection, he drew a round face with two hands in approximately the correct positions.

The case report on this patient's rapid improvement is "interesting," says William Thies, vice president of medical and scientific relations for the Alzheimer's Association, but he adds that "we're going to need more information before it's something that people should get wildly excited about."

"There are some kernels of good science here," says David Standaert, director of the Center for Neurodegeneration and Experimental Therapeutics at the University of Alabama at Birmingham, but he cautions that "this is not enough evidence that we would start treating people outside of a trial." Standaert was not involved in the work.

Etanercept has been used since 1998, primarily to treat rheumatoid arthritis. It's usually injected into the thigh, stomach, or upper arm, but Tobinick says that by injecting it into the neck, near the spine, the drug can reach the brain. It's a method that requires considerable skill. "It would be incorrect for anyone to think that they could just take Enbrel if they have Alzheimer's, and they'll get better," he says.

For decades, scientists have been trying to figure out how Alzheimer's disease does its damage so that they can determine how it might be treated. A hallmark of the disease is the globs of protein that form in the brain. There's mounting evidence that "part of what damages the brain is the body's own immune responses to these abnormal proteins," Standaert says. Various anti-inflammatory drugs have been trialed in Alzheimer's patients, but with disappointing results.

Etanercept reduces inflammation by blocking a protein called tumor necrosis factor (TNF), which plays an important role in immune responses. TNF occurs naturally in the brain, but studies have found elevated levels in people suffering from Alzheimer's disease.

Recent evidence suggests that TNF regulates the activity of synapses, which connect brain cells and enable electrical signals to travel around the brain. In Alzheimer's patients, an excess of TNF may wreck havoc on those connections, Tobinick says. "Even though the neurons may be working, the connections between the neurons and between the different lobes of the brain may not be working properly."

By using etanercept to reduce levels of TNF in the brains of Alzheimer's patients, Tobinick thinks he may have normalized those connections, leading to an immediate improvement in cognitive functioning. He says that he's working with academic partners to design larger-scale trials of the treatment. However, Sonia Fiorenza, a spokeswoman for Amgen, which markets Enbrel, says that the company won't be sponsoring trials because it doesn't believe there's enough evidence that it may be useful in Alzheimer's disease.

Some researchers want to see independent studies carried out, in part because Tobinick has disclosed that he has stock in Amgen and holds patents on the use of the drug and other anti-TNF agents to treat Alzheimer's disease.

It's not unusual for researchers to have a financial interest in something they're studying, Thies says, and "it doesn't stop them from doing good science." However, "you're going to have to have some independent confirmation in the hands of others."

"You have to do these [studies] double blind, placebo controlled, by people who don't have a financial interest," says J. Wesson Ashford, a senior research scientist at the Stanford University/VA Aging Clinical Research Center. (He was not involved in Tobinick's work.) "I'd really like to believe it, but I've seen it so many times, when people say something and it doesn't turn out to be anything."

"This is something that's got to be looked at," Griffin says. "I hope that scientists will pay attention to this, and the funding agencies will pay attention to this."

"This is not a cure," she adds, but if there's a person who can't dress or feed himself, is arrogant, mean, and up all night, "and you can take them to the point where they can feed themselves, they're calmer, attentive, conversational--in other words, you can stand them--that's great."

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