The Year in Biomedicine

Brain trauma among soldiers, a $5,000 genome, cellular switches, and insight into the brain’s beauty.

Brain Injury in Iraq
In April, we ran a feature exploring the new epidemic of brain injuries in U.S. soldiers serving in Iraq and Afghanistan, and the scientists racing to understand the often invisible wounds. One of the central questions–still unanswered–is whether mild brain injuries, undetectable with traditional brain scans, have a long-term impact, especially if caused by repeated traumas. Scientists are making progress using new brain-imaging technologies to find and monitor these subtle injuries.

Hidden wounds: Scientists have developed new methods to measure subtle brain injuries not visible on traditional brain scans. Here, a version of MRI known as magnetic resonance spectroscopic imaging is used to measure the levels of two chemicals–NAA and choline–in the brains of brain-injury patients and healthy controls. In the images above, the redder the color, the higher the ratio of choline to NAA. Brain-injury patients (bottom three rows) have a higher ratio of choline to NAA than do healthy people (top row).

Soon after the May issue of the magazine came out, President Bush signed into law the Traumatic Brain Injury (TBI) Act, which reauthorizes through 2011 federal programs in prevention, education, research, and community living for people with TBI. The U.S. Army beefed up screening requirements in June; all soldiers who experience dizziness or loss of consciousness from a blast, a fall, or some other trauma are to receive immediate medical attention. This is especially important because the impact of repeated mild TBI, which can be easy to shrug off and difficult to diagnose, is still unknown.

Ups and Downs for Personal-Genomics Companies
Startups offering genetic analysis directly to consumers, including 23andMe and Navigenics, have had a roller-coaster year. The Genetic Non-Discrimination Act, which prohibits genetic discrimination in employment or health insurance, passed after more than a decade of debate, removing a potential barrier to use. And retail genetic tests, specifically 23andMe’s, were named Time magazine’s best invention of the year. But it’s unclear whether either action has helped sales. 23andMe drastically reduced the price of its analysis service in September, prompting speculation of poor sales. And both companies have declined to report sales figures.

Navigenics and 23andMe also had to contend with regulatory skirmishes in New York and California, two states with strict laws on diagnostic testing. In June, the California Department of Health sent 13 personal-genomics companies cease-and-desist letters pending proof that they were complying with state law, including clinical licensing for the laboratories performing tests and the requirement of a physician’s order for all clinical tests. The state gave both companies the green light in August, but the regulatory future of personal genomics is still far from clear.

Reprogramming Stem Cells
Following the announcement late last year of a revolutionary technique to make stem cells from adult skin cells, scientists have now used the approach to generate stem cells from patients with a number of different conditions, including Parkinson’s disease, type 1 diabetes, muscular dystrophy, and Down syndrome. The cells can be differentiated into the cell type affected in each disease, such as motor neurons in Parkinson’s, allowing scientists to examine the molecular mistakes that might underlie these diseases and test drugs to prevent them. (See “Patient-Matched Stem Cells.”) Doug Melton’s team at Harvard took the process one step further, transforming one type of pancreatic cell into another without first making stem cells.

Scientists have also developed new variations of the reprogramming technique–most important, eliminating the need to use viruses that can potentially integrate into the host cell’s genome and raise risk of cancer. (See “Stem Cells without Side Effects.”)

Fast Sequencing
A little-known genomics startup made a splash in October by announcing a $5,000 genome. Rather than selling its technology, Complete Genomics, based in Mountain View, CA, will offer pharmaceutical companies and others a sequencing service. The claims met with some skepticism in the scientific community. A scientist at a recent genomics conference reportedly offered representatives of Complete Genomics $5,000 in cash for his genome, but was declined.

In August, Cambridge-based Knome doled out its first product, an individual’s genome, privately sequenced for $350,000 and delivered complete with an engraved silver box. Another of Knome’s customers, Dan Stoicescu, a millionaire living in Switzerland, announced plans to make his genome public. That data will join just a handful of complete human genomes.

The Brain Unveiled
In July, scientists unveiled the first detailed map of the network of connections in the human cortex. The feat required a combination of network analysis and a specialized version of magnetic resonance imaging that can measure the long thin wires that connect brain cells. The map revealed a highly interconnected central hub in the back of the brain.

A photo essay and interactive movies published online in November show brain images generated with this approach, called diffusion spectrum imaging.

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