Top 10 Medical Breakthroughs of 2008

1. First Neurons Created from ALS Patients

President-elect Obama has pledged to lift the seven-year ban on federal funding for embryonic stem-cell research — a boon for the field. But for some scientists, it almost doesn't matter. Researchers at Harvard and Columbia reported a milestone experiment in July, using a new method — one that doesn't require embryos at all — to generate the first motor neurons from stem cells in two elderly women with Lou Gehrig's disease, or ALS. The technique, developed by Kyoto University scientist Shinya Yamanaka in 2006, involves reprogramming a patient's ordinary skin cells to behave like stem cells, then coaxing them into the desired tissue-specific cells. Using the motor neurons created from ALS patients, scientists can now study the progress of the disease as the affected cells develop, degenerate and die in a dish — something researchers could never do before for such slow-moving conditions. Once scientists understand the development of ALS, they may be able to create more effective treatments, or perhaps even a cure.

2. Inflammation vs. Cholesterol

Half of all heart attacks in the U.S. occur in people with normal cholesterol levels. Baffled? So were doctors, until November. That's when Dr. Paul Ridker at Boston's Brigham and Women's Hospital confirmed a separate, perhaps equally powerful, risk factor for heart disease: inflammation, the same culprit behind arthritis and other autoimmune diseases. Smaller studies had hinted at the link in the past, but Ridker's recent research, published in the New England Journal of Medicine, showed that when people with normal cholesterol and high levels of CRP — a protein marker for inflammation in the blood — took statins, their CRP levels plummeted and their heart attack risk fell 54%. Compare that to the 20% reduced risk in people who take statins to lower cholesterol alone. Doctors say cholesterol and fatty plaques are still the main indicators of heart disease, but inflammation may be just as important, playing a key role as a trigger: It increases the instability of plaques, making them more likely to rupture, block heart vessels and cause a heart attack.

3. Scarless Surgery

Correction Appended: Dec. 15, 2008

It may sound outlandish, but doctors are increasingly experimenting with "natural orifice" surgery, a new technique in which surgeons enter the body through existing openings such as the mouth, vagina and colon, instead of cutting through the skin. A team at the University of California at San Diego performed the first such appendectomy in the U.S. in March, using camera-fitted scopes to guide the removal of a woman's appendix through her vagina. The technique is also helping some gastric bypass patients whose stomach tissue has stretched out post-surgery; doctors insert a scope through the mouth and gather up the stretched folds to shrink the stomach back to a smaller size. The technique isn't completely incision-free — surgeons make small cuts through tissue inside the body — but by reducing incisions through the skin, it could reduce pain and infection and promote faster recovery for some common surgical procedures.

The original version of this story misstated that the first natural orifice surgery was performed at the University of California at San Diego this year. In fact, the first procedure was performed at NewYork-Presbyterian Hospital/Columbia in 2007, to remove a gallbladder. The UCSD procedure was the first such appendectomy.

4. Genomes for the Masses

James Watson, co-discoverer of the structure of DNA, did it. So did Craig Venter, co-mapper of the human genome. Now you, too, can map your entire genome and reveal some of its many secrets — for just $399 and a little spit. Scientists debate whether that information is really worth anything at the moment — in many cases, there isn't enough scientific knowledge to interpret what it really means to have this gene variant or that one — but companies like 23 and Me at least make it possible for you to take a gander at your genetic data. (Although the service was available previously, until this year, it's been prohibitively expensive.) You provide a sample of saliva, from which your DNA is extracted, copied and combed for the presence of 90 known genetic variations that code for different traits or conditions, from lactose intolerance (though you could probably drink a glass of milk and find out for far cheaper) to prostate cancer. Right now, there's no way to know whether you'll get cancer just because you have the gene, but once the science has advanced, the hope is that such genetic mining will predict disease, giving people the option of seeking treatment before they get sick.

5. New Genes for Alzheimer's

There is no cure, no vaccine and no way to diagnose Alzheimer's disease without an autopsy. But there may be hope in the discovery of four new genes that contribute to the most common form of the disease. The genes emerged from a study of over 1,300 families, and although the genes' exact role in Alzheimer's isn't known yet, researchers think they may contribute to the death of nerve cells. As the disease progresses, fatty plaques and fibrous tangles of protein build up in the brain, ensnaring nerve cells and eventually strangling them to death. The newly identified genes may shed light on how to keep those nerves alive, which may be an important target for future therapies. Even more exciting is that one of the genes produces a protein that nerve cells use to communicate, another function that declines when Alzheimer's sets in. Dozens of genes have already been linked to Alzheimer's, but each newly discovered gene represents a new target and new hope for future drug treatment.

6. A Five-in-One Vaccine

Any parent can appreciate how much babies hate shots. So, welcome Pentacel, the first vaccine to immunize against five diseases at once — diphtheria, tetanus, pertussis, polio and haemophilus influenzae type B. The vaccine was studied in more 5,000 infants, who showed only minor side effects, including fever, redness and swelling at the injection site. Pentacel still has to be administered in four separate doses, three times between the ages of 2 and 6 months, then again between 15 and 18 months — but it cuts down by 30% on the 23 injections toddlers under 18 months normally receive. Telescoping immunizations may help to get more kids up to date on their immunizations; so far, 77.4% of kids aged 19 to 35 months have received all of their vaccinations, which is just shy of the government's goal of 80% by 2010.

7. Gene Screens for Breast Cancer

Gene screens are fast becoming a powerful tool, not just for diagnosing cancer but for treating it as well. Joining the growing pool of genetic tests for breast cancer, SPOT-Light mines patients' genes to determine who will respond best to the cancer drug Herceptin, which is effective against tumors that release an abundance of the HER2 protein. The SPOT-Light test can measure how many HER2 genes are present in a sample of breast tumor; the more genes there are, the more likely the tumor will respond to treatment with Herceptin. Breast cancer patients are also increasingly relying o n another gene test, OncotypeDx, which can determine the risk of breast cancer recurrence and which chemotherapy agents will work best against a particular tumor.

8. Blood Test for Down Syndrome

One of the best ways to confirm Down syndrome before birth is by amniocentesis, which uses a needle to remove a sample of the amniotic fluid surrounding a fetus. But needles can be nerve-wracking, especially when they're aimed at a growing baby in the womb, and the procedure carries a 1 in 200 risk of miscarriage. Now, a new genetic test may be able to pick up the disease with a simple blood sample from the mom-to-be. Because small amounts of fetal DNA enter the mother's bloodstream, the test is designed to detect abnormally elevated levels of chromosome 21 (an extra copy of it causes Down) in the mother's blood, which would indicate a baby with the disease. The test is still in the development stages, but could herald a new way to identify certain genetic conditions.

9. Seasick Patch for Cancer Patients

Those motion-sickness patches can really help calm a churning stomach on a boat. So, someone decided to apply the same idea to deliver anti-nausea drugs to cancer patients after chemotherapy. In September, the FDA approved Sancuso, a patch that releases a continuous dose of the drug granisetron, which blocks serotonin receptors and reduces queasiness. The prescription drug is already available to cancer patients in solution, tablet or injection form, but the patch makes delivery easier and more convenient. Once on, the Sancuso patch quells nausea and vomiting for about five days.

10. Stem-Cell Trachea Transplant

In a transplant first, doctors in Spain gave Claudia Lorena Castillo Sanchez, 30, a new windpipe, constructed from a donor trachea lined with Sanchez's own stem cells. It's the first time a patient's adult stem cells, extracted from bone marrow, have been used to seed a new tissue or organ for transplant. Because the donor trachea was stripped of cells that could cause rejection, Sanchez, who suffered from tuberculosis and lost function of one branch of her trachea, avoided having to take the powerful immunosuppressant drugs that transplant patients normally require. Doctors expect that this type of transplant, which is still experimental, will need several more years of study before it becomes widely used. But Sanchez, for one, is happy she didn't have to wait that long; the mother of two is already back to work and enjoying dancing six months after her operation.