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Domain: ahajournals.org
Stories and comments across the archive that link to ahajournals.org.
Stories · 3
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Air Pollution Linked To Changes In Heart Structure, Study Shows (theguardian.com)
Researchers say air pollution is linked to changes in the structure of the heart of the sort seen in early stages of heart failure. "The findings could help explain the increased number of deaths seen in areas with high levels of dirty air," reports The Guardian. From the report: "What we don't know is what is the mechanism behind it, why is air pollution leading to increased risk of heart attack and stroke?" said Dr Nay Aung, a cardiologist at Queen Mary University of London and first author of the research. The latest study helps to unpick the conundrum. Writing in the journal Circulation, Aung and colleagues report that they found exposure to nitrogen dioxide and fine particulate matter, known as PM2.5 and PM10 particles, is linked to an increase in the size of two of the chambers of the heart, the left and right ventricle. PM particles are commonly emitted by motor vehicles, among other sources. The authors add that similar changes can affect the performance of the heart and are often seen before heart failure takes hold.
The team used data from almost 4,000 volunteers who were part of a wider research effort known as the UK Biobank. These participants were aged between 40 and 69 years old, had been at the same address for the whole study, and were free from cardiovascular disease at the outset. Crucially, their data included cardiac MRI scans, which offer detailed images of the structure and function of the heart. The study also involved estimates of the outdoor concentrations of different pollutants at participants' home addresses at about five years prior to the scan. After controlling for factors including age, sex, income and smoking history, the team found that higher exposure to PM2.5 particles, PM10 particles and nitrogen dioxide were each linked to a greater volume of both the right and left ventricles after they had filled with blood. -
E-Cigarettes With Nicotine Increase Your Risk of Heart Disease, Says Study (theverge.com)
An anonymous reader quotes a report from The Verge: Even after puffing on just one electronic cigarette with nicotine, healthy non-smokers were found to have a biological marker known to increase the risk of heart disease in tobacco users, according to a new study. The research, published in Journal of the American Heart Association, shows that nicotine is not harmless, as many people believe. It can affect a smoker's health in more than one way, and not just by triggering addiction. Another study, conducted by Middlekauff that was published earlier this year, showed that people who use e-cigs almost every day have biological markers known to increase the risk of heart disease in tobacco users. These included an increase in adrenaline levels in the heart, which can predispose smokers to bad heart rhythms, heart attacks, and sudden death, as well as increased oxidative stress, an imbalance in the body's ability to defend itself against the damaging action of free radicals. Oxidative stress can lead to changes in blood fats and lead to arteriosclerosis.
That study, however, didn't show what exactly was causing those changes. E-cigarettes can have different flavoring and solvents, as well as nicotine. So to identify the culprit, Middlekauff brought 33 healthy non-smokers and non-vapers into the lab. On three different days, one month apart, the participants were asked to puff on three different kinds of e-cigarettes for 30 minutes: one with nicotine, one without nicotine, and a sham e-cig that was empty. The researchers did blood tests and measured the subjects' heart rhythms, and found that the participants had high levels of adrenaline in their hearts after they smoked the e-cig with nicotine, but not after they puffed on the e-cigarette without nicotine or the empty e-cig. -
Scientists Use Stem Cells To Regenerate the External Layer of a Human Heart (indy100.com)
schwit1 quotes a report from Indy100: A team of scientists from Massachusetts General Hospital and Harvard Medical School have used adult skin cells to regenerate functional human heart tissue. The study, published in the journal Circulation Research, detailed that the team took adult skin cells, using a technique called messenger RNA to turn them into pluripotent stem cells, before inducing them to become two different types of cardiac cells. Then for two weeks they infused the hearts with a nutrient solution, allowing them to develop under the same circumstances a heart would grow inside a human body. After the two week period, the hearts contained well-structured tissue, which appeared similar to that contained in developing human hearts. When shocked with electricity, they started beating. This represents the closest that medical researchers have come to growing an entire beating human heart.