Research showing blood components from young can rejuvenate an old mouse's muscles and brain came second in Science breakthrough of the year.

As Science notes, the work has profound implications. " If the results hold up in people-an idea already in testing- factors in young blood could offer the antidote to aging."

Work published in 2014 strengthened the evidence that something in young blood can reverse multiple signs of aging. One group studied a factor isolated from young mouse blood called GDF11, which had already been shown to rejuvenate the heart. They found that it can also boost the muscle strength and endurance of an old mouse and spur neuron growth in the brain. Another team reported that young blood, or even cell-free blood plasma, bolsters an aging mouse's spatial memory.

Now in the first clinical trial that includes 18 middle-aged and older Alzheimer's patients, patients are being given injections of blood plasma provided by young adults to see if it can help fight dementia. Results are expected next year.

Cells that might cure diabetes

Another notable Breakthrough highlighted by Science was finding the methods for growing cells that resemble human β cells.

According to Science, since the discovery of human embryonic stem (ES) cells, researchers have hoped to wield them against disease.  This year, researchers came closer than ever to that goal, when two groups published methods for growing cells that resemble human β cells. One approach works with both ES cells and so-called induced pluripotent stem cells—reprogrammed cells that can be made from a patient's skin cells. The recipe is complex, and it takes 7 weeks to convert stem cells into the insulin-producing cells. But researchers can grow 200 million of the β-like cells in a 500-ml flask—in theory, enough to treat a patient. The other method takes 6 weeks and can produce one β-like cell for every two ES cells at the start. To use the cells to treat type 1 diabetes, researchers need to develop ways of protecting them from the autoimmune reaction that kills β cells in the first place. Meanwhile, the grown-to-order cells give scientists an unprecedented chance to study diabetes in the lab. Researchers have already started to compare β cells made from skin cells of healthy subjects with those made from patients with diabetes, hoping to pinpoint the key differences.

Being able to manipulate memories also made the Science list this year.

As science notes, memory is notoriously malleable. Our recollections fade and take on new meanings; sometimes we remember things that never even happened. But just what is happening in our brain as memories are remodeled remains mysterious.

Researchers discovered ways to manipulate specific memories in mice using optogenetics, a powerful technique that can trigger nerve cells in animals' brains by zapping them with beams of laser light. In a series of experiments, they showed that they could delete existing memories and “incept” false ones. This year, researchers went even further: switching the emotional content of a memory in mice from bad to good and vice versa. Under the laser, for example, male mice that had once associated a certain room with being shocked were tricked into acting as though they had once met friendly female mice there instead.

Whether the mice in these experiments actually experienced vivid false memories or just a fuzzy sense of pleasure or fear is unclear. Nor is it clear whether the findings apply to the tricks of memory so familiar to people. Long-sought therapeutic advances, such as treatments for post-traumatic stress disorder, could remain far off. One thing is certain, however: Once considered beyond scientific dissection, memory is finally starting to yield its secrets.

However, the overall winner of Science's Breakthrough of 2014 involved work by researchers who added two artificial versions to the alphabet of natural nucleotides that make up genetic code.

According to Science, everywhere on Earth, the genetic code at the heart of living things consists of the same four genetic letters. Everywhere, that is, except in a flask of Escherichia coli bacteria on a lab bench in southern California. There, researchers this year engineered the bacteria to incorporate two additional letters into their genetic alphabet. In addition to the natural nucleotides, in which G pairs with C and A pairs with T, the bacterial DNA includes a novel pair: X and Y.

Researchers around the globe had already devised several pairs of “unnatural” nucleotide bases that, in the test tube, could fit within DNA's double helix. They also managed to get DNA's copying machine, an enzyme known as DNA polymerase, to copy some of these new pairs. But no one had ever made it all happen inside living organisms—until this year.

For now, the new letters in the E. coli DNA don't code for anything, but in principle, researchers could use them to create designer proteins that include “unnatural” building blocks: amino acids beyond the 20 encoded by the bases in normal DNA. Researchers have previously used genetic tricks to do that with natural DNA. But adding the new X-Y combo should make the process far easier. That could be a godsend for makers of medicines and materials. And perhaps not the only one: This year, in a parallel effort to tailor DNA, synthetic biologists also modified its chemistry to create novel catalysts.

Eventually, the expanded genetic code could also serve a more academic pursuit, enabling researchers to test whether bacteria equipped with the excess letters might evolve novel skills not found in their wild kin. That may sound like a scenario for a dystopian techno-thriller, but the researchers say there's no need to worry: Because unnatural DNA letters don't exist outside the lab, any bacterial escapees would not be able to replicate their artificially expanded genetic instructions and pass them on to their offspring.

Science’s top ten breakthroughs

• Giving life a bigger genetic alphabet. How scientists added new letters to the genetic code.

• Bringing in new blood. Researchers show blood components from the young can rejuvenate an old mouse’s muscles and brain.

• Landing on a comet. Rosetta’s ten-year mission to comet 67P promises to transform our knowledge about the solar system.

• Cells that might cure diabetes. Researchers create insulin-making cells in the laboratory.

• Cooperative robots. Engineers use novel software to create fleets of tiny robots that can gather in formations and build simple structures.

• The birth of birds. Scientists detail the many steps that turned lumbering dinosaurs into graceful birds.

• Chips that mimic the brain. IBM and other companies have designed neuromorphic chips that process information in ways close to living brains

• Cave art. Scientists quadruple the age of cave art in Indonesia.

• Manipulating memory. Researchers have found ways to delete existing memories in mice and insert new ones.

• The rise of the CubeSat. Tiny 10cm-wide boxes containing a few thousand dollars worth of equipment are being used increasingly as cheap satellites.

News source: Science, AAAs, theguardian

Dr. Shima Naghavi, Director of International Affairs