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.

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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.

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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.

“We took the recipe for this process from a complex minestrone to a simple miso soup,” says study leader Elias Zambidis.

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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.”

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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]

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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]

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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.

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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]

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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]

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Dick Cheney may not have a pulse, but part of his ticker is spinning at 9,000 RPM.

The former Vice President provided an instant laugh line for comedians this week when it was revealed that during his latest heart surgery, doctors installed a new implant called left ventricular assist device, or LVAD.

The pump runs something like a drill bit, continuously rotating at 9,000 rotations per minute rather than squeezing and releasing, so Cheney now officially has no pulse, according to Dr. Stuart D. Russell, chief of heart failure and transplantation at Johns Hopkins’ Comprehensive Transplant Center [Baltimore Sun].

A device like Cheney’s is implanted in his chest, with the exception of the batteries, which the user must wear in a separate vest. (Though the Baltimore Sun reports that patients can wear the power source “holster style,” which may be more Cheney’s style.)

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When a person has a heart attack, the heart repairs its damaged muscle by forming scar tissue. As a result, the heart never truly goes back to the way it was. But when a zebrafish has a heart injury, like having a large chunk of it chopped off, it grows a brand new piece to replace it.

Two independent reports published in the journal Nature show that within days of an injury to its heart, the zebrafish has the remarkable ability to regenerate most of the missing cardiac tissue using mature heart cells–not stem cells, as some researchers had suspected.

The findings help explain why human beings can’t regenerate a heart or missing limbs. The reports contradict a previous study (pdf) done by one of the research teams in 2006 that suggested that stem cells, the general all-purpose cells that develop into all the mature and functional cells of the body, were responsible for self-repair.

The finding suggest that doctors have been on the wrong track with recent stem cell-based therapies for heart attack patients. Many heart patients have received injections of stem cells, often ones taken from their own bone marrow. But the beneficial effects have generally been unremarkable [The New York Times].

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Former President Bill Clinton is out of the hospital today after seeing a doctor in New York about chest pains this week. Clinton showed no evidence of a heart attack and his prognosis is excellent after a procedure Thursday to insert two stents in a coronary artery that had become blocked, said his cardiologist Dr. Alan Schwartz [Los Angeles Times].

Clinton’s rush to the hospital brought new attention to the common medical practice of using stents in heart patients. A stent is a small wire mesh tube that is inserted into an artery in order to prop it open, like a miniature scaffold. Surgeons use stents to improve blood flow to the heart muscle and relieve symptoms such as the chest pain that Clinton experienced [ABC News]. Most people who undergo coronary angioplasty procedures receive stents. Once the tube is in the artery, the artery grows over it and it becomes a permanent part.

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We’ve brought you stories of lab-created blood cells able to simulate red blood cells in humans, or to act like platelets in rodents and stop bleeding. Now, in a study soon to be published in the Proceedings of the National Academy of Sciences, comes a new, even smaller creation for our bloodstreams: A nanoparticle that could target and latch onto only the damaged cells in arteries around the heart to deliver drugs there.

The MIT researchers, led by Robert Langer, have developed other nanoparticles to target cancer; this new particle they call a “nanoburr,” named for those seeds covered in bristles or hooks that latch onto animals passing by. Its nanoburrs are coated with proteins which can only stick to a structure in the blood vessel wall called the “basement membrane.” This is only exposed when the wall is damaged, so only damaged sections of blood vessel are targeted [BBC News]. Then the particle can slowly release the drug stored inside.

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There’s a new addition to the parade of studies investigating potential health problems connected to the ubiquitous plastics ingredient bisphenol A (BPA). But while the new data backs up the connection between BPA and heart disease that appeared in previous studies, the nature of the link still isn’t conclusive, and other links are not clear.

The study in PLoS One analyzed data gathered between 2003 and 2006. The association with diabetes is a bit weaker [than shown in earlier studies], but the one with heart disease remains robust. In fact, the authors are able to show a linear relationship between BPA exposure and cardiovascular disease in both data sets [Ars Technica]. While the authors confirmed that BPA-heart disease link from their 2008 study, they said they still could not sufficiently tell correlation versus causation and called for more study.

They did find another interesting tidbit, though, this one being on the good side. BPA levels in the urine of test participants plunged by 28 percent from the 2003/04 period to the 2005/06 period. That’s odd because it predates the wave of public concern over BPA, though perhaps changed industry practices are responsible, study author David Melzer says. “BPA in baby’s bottles has been very controversial and we speculate that manufacturers may be switching to other plastics for use involving food and beverages” [Scientific American].

Related Content:
80beats: Study: The Chemical BPA, in High Doses, Causes Impotence
80beats: More Bad News on BPA: Linked to Heart Disease and Diabetes in Humans
80beats: BPA Won’t Leave Public-Health Conversation—or Your Body
80beats: Plastic Is More Biodegradable Than We Thought. (That’s Bad.)
80beats: FDA Declares Chemical in Baby Bottles Safe, But Doubts Remain
DISCOVER: The Dirty Truth About Plastic

Image: iStockphoto

This week brings more vindication for a childhood full of bumps, bruises, and going outside, rather than sterile modern living. In a long-term study published in The Proceedings of the Royal Society B, U.S. researchers suggest that over-cleanliness could make babies more prone to inflammation later in life, and in turn raise the risk for stroke and heart disease.

Thomas McDade’s team studied more than 1,500 people in the Philippines who had health surveys at age two and then again at age 20. The team tested them for C-reactive protein (CRP), a marker of inflammation. They found that the more pathogens the people had encountered before age 2, the less CRP they had at age 20. Every episode of diarrhoea back then cut the chance of higher CRP later by 11 per cent; every two months spent in a place with animal faeces cut it by 13 per cent. Being born in the dusty, dirty dry season cut the chance by a third [New Scientist].

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