Mount Everest is often the site of impressive physical feats, as climbers brave brutal conditions to scale the tallest peak in the world. But the extreme altitude takes quite a toll on the body, causing hypoxia, muscle loss, sleep apnea, and other ill effects. Many of the same symptoms are more commonly found in elderly patients suffering from heart conditions or other chronic ailments—meaning Everest provides a natural laboratory for researchers to gain a better understanding of these diseases.
With optogenetics, a technique that uses beams of light to control the activity of particular cells, researchers have already flicked on clusters of neurons that trigger aggressive behavior and ramped up insulin production in mice. Now, scientists are applying the technique to the heart, working towards a cardiac pacemaker driven by light, Courtney Humphries reports in Technology Review.
Smooth-muscle cells show green in this comparison of blood vessels grown with (right)
and without (left) growth factor FGF9. Without muscle, vessels don’t pump.
What’s the News: Biologists may have been barking up the wrong tree when it comes to growing new blood vessels to provide blood to tissues damaged by heart disease. The vessels that form under the influence of a growth factor intended to kick-start the process are sickly and shrivel up within a year, but a new study in Nature Biotechnology ($) shows that focusing on making the surrounding cells provide support may solve the problem.
If you send stem cells just the right signals, they’ll develop into any one of a wide range of tissues, from retina to spinal cord to heart muscle. But which signals to send? A team at John Hopkins has painstakingly gone over more than 30 techniques for getting cells to differentiate and consolidated them into a simple procedure that has successfully been used to turn at least 11 lines of stem cells into healthy, beating heart cells—all without introducing the cancer-causing mutations that can plague this kind of work.
What’s the News: Scientists found that periodic fasting may decrease the risk of coronary artery disease and diabetes, and also causes significant changes in heart-disease risk factors like cholesterol, blood-sugar, and triglyceride levels, which hadn’t been linked to fasting before. “We’ve shown it is not a chance finding. Fasting is not just an indicator for other healthy lifestyles,” says lead researcher Benjamin Horne of the Intermountain Medical Center Heart Institute. “It is actually the fasting that is working to reduce the risk of disease.”
Smoke is in the air again. Well, smoking, rather. The newest report by the Surgeon General (yes, they’re still doing those) came out this week, and the 30th installment of this institutional dispatch ratcheted up the message. It’s not just a lot of smoking that will kill you; the Surgeon General’s office is now pushing the idea that even one cigarette is one too many—serious damage can start immediately, says the report.
Thursday’s report says there’s no doubt that tobacco smoke begins poisoning immediately — as more than 7,000 chemicals in each puff rapidly spread through the body to cause cellular damage in nearly every organ. “That one puff on that cigarette could be the one that causes your heart attack,” said Surgeon General Regina Benjamin. [AP]
It’s not exactly a revelation that smoking is risky and get riskier the more you do it. However, this is the first in the long line of these reports to really press the points that have turned up in recent research, like epigenetic changes or immediate risk to the cardiovascular system.
The root of the problem is that even small amounts of the chemicals in cigarette smoke cause rapid inflammation in the endothelium, or lining, of blood vessels and in the lungs. Inflammation is increasingly blamed by researchers as a key promoter of blood vessel plaques and clots and in obstructive lung diseases like emphysema. “The evidence on the mechanisms by which smoking causes disease indicates that there is no risk-free level of exposure to tobacco smoke,” the report concludes. [WebMD Health News]
Is plain old aspirin the best medicine to ward off cancer? A new study in The Lancet says that it could definitely help, but researchers urge caution before anybody goes on a low-dose aspirin regimen for this reason.
The study, led by Oxford’s Peter Rothwell, is actually a review of eight previous studies that compared people on regular doses of low-dose aspirin to those on a placebo. The researchers who initially performed the studies were investigating questions like whether the aspirin regimen was effective in lowering the risk of heart disease. But in doing so, they kept detailed records on the more than 25,000 people who were involved in the studies—including their causes of death.
Deaths from esophageal cancer were reduced by 60% in the aspirin-takers (who took the drug for at least five years), compared with the placebo group. Lung cancer deaths were reduced by 30%, colorectal cancer deaths were cut by 40% and prostate cancer deaths were lowered by 10%, compared with the patients who got placebo. What’s more, the longer people took aspirin, the greater their reduction in cancer risk. [TIME]
After two years of work developing new guidelines to tell us how much vitamin D and calcium is enough, the Institute of Medicine released its report this week with the basic message: Relax, you’re all doing pretty well.
Yet confusion still reigns in headlines about the report, as there are several different facets to the new standards (and the reaction to them). The new report also seem to contradict earlier, alarming studies that found vitamin D deficiencies in most Americans. So, what’s going on?
Most people are doing just fine
IOM looked at both Vitamin D and calcium intake for different age groups, and slogged through hundreds of studies of the levels of those nutrients versus health. The only group that was found deficient was adolescent girls, whom the researchers said should intake a little bit more calcium.
The panel said its findings challenged the notion that, when it comes to dietary nutrients, “more is better” — a belief that has inspired a multibillion-dollar market for dietary supplements in the United States. Americans spent $1.2 billion last year on calcium supplements and $430 million on pills containing vitamin D, according to the Nutrition Business Journal. [Los Angeles Times]
Ohio State oncologist Steven K. Clinton, a coauthor of the report, says most people have enough variety in their normal diet to get adequate amounts of both nutrients.
New findings? Not convincing enough
The reason that gigantic supplement market exists is that a number of studies have suggested vitamin D—found in some foods but mostly produced in your skin by the action of ultraviolet radiation—could help to prevent diseases like cancer, heart disease, diabetes, and more. But in its meta-review of vitamin D studies, IOM wasn’t convinced. Its report reinforced the traditional wisdom that vitamin D is crucial for skeletal health, but wouldn’t go further in determining healthy levels.
In early 2010, some scientists offered their predictions for the new decade which this blog covered in the post, “Scientists Predict: The 2010s Will Be Freakin’ Awesome–With Lasers.” In what could be an early sign of that sunny prognostication coming true, researchers have announced that they’ve controlled the beating of an embryonic heart with an infrared laser beam. While the work is in its early stages, researchers say this remarkable advance will help them study heart disease and could one day lead to optical pacemakers.
The embryonic hearts in question came from quail eggs. Each quail embryo was only two or three days old so the heart measured just 2 cubic millimeters in volume; at that stage, the heart is essentially a clump of cells that hasn’t yet developed its four-chambered structure. The pulses of infrared light were delivered by an optical fiber that ended 500 micrometres from the embryo.
Before they switched on the laser, the heart beat once every 1.5 seconds, but firing the laser twice a second quickened the heartbeat to match the laser rate as long as the laser fired…. “It worked beautifully: the heart rate was in lockstep with the laser pulse rate,” says [study coauthor] Duco Jansen of Vanderbilt University in Nashville, Tennessee. [New Scientist]
In January, we discussed a biotech first–a transformation from skin cell to brain cell, without reverting to a more mutable stem cell in between. Today a paper in the journal Cell describes a similar direct transformation in mice, from a type of structural cell called a fibroblast to heart cells. If one day scientists can entice human cells to make a similar “direct conversion,” the researchers believe this metamorphosis may prove one way to fix heart damage that’s irreparable under the current state of medicine.
The study’s authors at the Gladstone Institute of Cardiovascular Disease at the University of California, San Francisco, once attempted to use stem cells for heart repair with little success, Nature News reports. Though the stem cells quickly turned into the beating variety, called cardiomyocytes, they remained feeble, never transforming into the strongly beating muscle cells of a healthy heart.
“I don’t know that this [direct conversion] will entirely replace stem cells,” says Deepak Srivastava [lead author on the study]… “But it will offer another strategy that might remove some of the concerns of using stem cells.” [Nature News]