Certain maladies march forward through time, growing progressively more devastating. Now, scientists can turn back the clock.
1. Alzheimer’s Disease: Young blood repairs memory
More than five million Americans are currently living with Alzheimer’s disease, a number that’s expected to nearly triple by 2050. Despite billions spent on research, the hunt for a cure has had little success. But new studies led by Tony Wyss-Coray, a neuroscientist at Stanford University, point to an unusual solution.
When Wyss-Coray began studying the blood of Alzheimer’s patients, he noticed a marked difference from that of healthy individuals. Because the composition of blood changes with age, he wondered whether simply providing an infusion of young blood could impact the aging brain. To find out, he and his colleagues conducted a rather gruesome experiment: They stitched old and young mice together so that they shared a single circulatory system. Over the next five weeks, the young mice produced fewer new neurons and the old mice produced more. Next, the researchers injected old mice with young plasma, the fluid that remains when you strain the cells from blood. When tested in a maze, treated mice appeared to learn more easily and remember better.
5,000,000: Number of Americans living with Alzheimer’s disease
The researchers are still trying to pinpoint what makes young blood so powerful. The plasma may contain proteins that quiet inflammation, a potential cause of Alzheimer’s; identifying those proteins may lead to new therapies. The team has launched a clinical trial to test the theory in humans: 18 patients will receive infusions of youthful plasma to see whether it improves Alzheimer’s symptoms. It’s a leap of faith, Wyss-Coray says, but one with few risks and tremendous potential.
2. Diabetes: New techniques shed weight and lower blood sugar
Many people with diabetes control their illness with hefty doses of insulin and a smorgasbord of pills. For years, George Treff was one of them, but eventually, his body stopped responding. Even diet and exercise didn’t help. “Whether I fasted or I sat down and ate 20 pounds of chocolates, nothing was really changing,” he says. So in April 2009, Treff, who weighed 240 pounds at the time, tried something new: Roux-en-Y gastric bypass, a surgery typically reserved for morbidly obese patients.
The operation shrinks the stomach and reroutes the digestive tract. Postsurgery, patients eat less and absorb fewer nutrients, so they lose weight. Some people also show metabolic improvements in just a few days. In the wake of his surgery, Treff’s blood sugar plummeted, and for a long time afterward, he didn’t need to take insulin. Today, he takes just a fraction of the dose he once required. “These operations are better for treating diabetes than they are for treating obesity,” says Carel Le Roux, a physician at the University College Dublin. New research may help explain why: The body increases production of bile acids, which bind to a receptor called FXR, prompting the release of hormones that help regulate blood sugar.
Scientists are now trying to use medication to the same effect. Michael Downes, a molecular biologist at the Salk Institute in La Jolla, California, published a study in January showing that a pill designed to activate FXR in the intestine helped mice shed weight and control their blood sugar. The pill could be even more effective than surgery. “You get all the metabolic benefits,” Downes says—without the knife.
3. Blindness: Stem cell therapy restores eyesight
People with age-related macular degeneration lose their vision slowly. Many never go totally blind, but objects blur, colors dim, and eventually faces can become unrecognizable. Last fall, Ocata Therapeutics announced a human embryonic stem cell therapy that could help restore disintegrating eyesight.
In the most common form of the disease, a thin layer of tissue, called the retinal pigment epithelium, begins to deteriorate. This tissue delivers nutrients and oxygen to the eye’s rods and cones; without it those photoreceptors fail. Ocata coaxes embryonic stem cells to become retinal pigment epithelium cells, which can then be injected into the eyes. What happens next is still unclear: The cells may rejuvenate sickly rods and cones or generate new ones, says Eddy Anglade, chief medical officer for Ocata. Either way, people begin to see again.
Data from the company’s first two clinical trials, published last year, confirm the treatment works. Ten of 18 people experienced some improvement in their vision, and the therapy seemed to halt the loss of vision in another seven. Some even had a dramatic recovery: A 75-year-old rancher who had gone blind in one eye was able to start riding his horses again. It’s likely still a few years from Food and Drug Administration (FDA) approval, but Anglade hopes the treatment will one day become as common as cataract surgery.
4. Heart Failure: Gene therapy keeps hearts pumping
A failing heart leaves people tired, weak, and short of breath. Some ultimately need a transplant. But soon, there may be another option: gene therapy.
In order to beat, a heart’s muscle cells must contract and relax. To contract, calcium ions flow out of the cells through a special organelle. To relax, a protein called SERCA2a pumps them back in. Failing hearts tend to have less of this protein than normal hearts, so Roger Hajjar, a cardiologist at Mount Sinai Hospital in New York, developed a way to deliver more. His lab engineered a virus to carry extra copies of the gene that codes for SERCA2a into heart cells and insert them into the DNA. Consequently, the cells increase SERCA2a production. Although the protein can’t undo existing damage, it can help the remaining cells work harder.
In 2007, researchers tested the therapy, called MYDICAR, in a clinical trial of 51 heart failure patients. Those who received the highest dose had fewer heart attacks and heart transplants. Three years later, they’d also experienced fewer heart-related hospitalizations and deaths. In 2012, the team launched a study of 250 patients. And last year, MYDICAR received a breakthrough-therapy designation from the FDA, which will accelerate the review process. Sian Harding, a researcher at Imperial College London and Hajjar’s collaborator, is optimistic about its prospects: “The therapy could allow you to live out a normal life,” she says.
5. PTSD: Brain stimulation counteracts depression
The wars in Iraq and Afghanistan took a toll on the more than two million American men and women who served in them. Studies suggest that roughly one in five veterans will experience post-traumatic stress disorder (PTSD). For some, the nightmares and anxiety—hallmarks of the illness—disappear on their own. But for others, no amount of counseling and medication seems to help. “PTSD is associated with a tremendous amount of suffering,” says Ralph Koek, a psychiatrist at the VA Sepulveda Ambulatory Care Center in Los Angeles.
Roughly one in five veterans will experience post-traumatic stress disorder.
That’s why Koek and his colleagues recently launched the first human study to see whether deep brain stimulation could help veterans who have failed to respond to other PTSD treatments. The team plans to implant electrodes in each of the six participants’ amygdala, the region of the brain that links events to emotions. “In PTSD, it seems that the amygdala is linking events to fear,” says Jean-Philippe Langevin, a neurosurgeon at the VA Greater Los Angeles Healthcare System. Scientists think the device may jam the signal coming from a hyperactive amygdala and help to extinguish the excessive fear people with PTSD feel in response to everyday events. Animal research seems to support that: A 2012 study on rats found that deep brain stimulation reduced hypervigilance more effectively than antidepressants. DARPA is working on similar research.
In 2013, the agency launched a $70-million, five-year program to develop a brain implant. The device will monitor specific neural circuits, with the same goal: “We’re aiming to transform people’s lives,” Langevin says.
This article was originally published in the April 2015 issue of Popular Science
