Chronic stress has been linked to memory loss in new research.

How chronic stress can make you forgetful and inflame your brain

Also in health news this week: a smartphone app that measures blood pressure is returning false readings in eight out of 10 users, and tobacco smoke residues on clothes and surfaces can trigger diabetes

Jeanette Wang

Published: 8:01am, 5 Mar 2016

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Sustained stress erodes short-term memory, and the immune system plays a key role in the cognitive impairment, according to a new study in mice from Ohio State University researchers. Mice were exposed to chronic stress through repeat visits from a larger, nasty intruder mouse. These mice had a hard time recalling where the escape hole was in a maze they’d mastered prior to the stressful period.

“The stressed mice didn’t recall it. The mice that weren’t stressed, they really remembered it,” says lead researcher Jonathan Godbout, an associate professor of neuroscience. The stressed mice also had measurable changes in their brains, including evidence of inflammation brought on by the immune system’s response to the outside pressure. This was associated with the presence of immune cells, called macrophages, in the brain of the stressed mice. The research team was able to pin the short-term memory loss on the inflammation, and on the immune system. “Stress releases immune cells from the bone marrow and those cells can traffic to brain areas associated with neuronal activation in response to stress,” says researcher John Sheridan. “They’re being called to the brain, to the centre of memory.”

Concern has been raised over the accuracy of a blood pressure app for smartphones.

Popular blood pressure app misses problems in 80pc of users

A popular smartphone app purported to accurately measure blood pressure simply by placing a cellphone on the chest with a finger over the built-in camera lens misses high blood pressure in eight out of 10 users, potentially putting their health at risk, according to research from Johns Hopkins University in the United States. Although the app, called Instant Blood Pressure, is no longer available for purchase, it was downloaded more than 100,000 times and is still functional on phones, the researchers say. “We think there is definitely a role for smartphone technology in health care, but because of the significant risk of harm to users who get inaccurate information, the results of our study speak to the need for scientific validation and regulation of these apps before they reach consumers,” says Dr Timothy Plante, a fellow in the division of general internal medicine at the Johns Hopkins.

The researchers recruited 85 adult volunteers among patients and staff members in clinics associated with Johns Hopkins Medicine. Each participant had his or her resting blood pressure measured twice using a reliable automated blood pressure monitor commonly used in research studies, and twice using the app on the same day. Close to 80 per cent of those with clinically high blood pressure, defined as 140/90 millimetres of mercury or above, measured by the automated blood pressure monitor showed normal blood pressure with the app.

Third-hand smoke linked to type 2 diabetes

Third-hard smoke – that found on surfaces that exhaled tobacco smoke touches, such as clothing, hair and furniture – has shown in a new study on mice to cause insulin resistance, a precursor to type 2 diabetes. “If confirmed in humans, our study could greatly impact how people view exposure to environmental tobacco toxins,” says Manuela Martins-Green, a professor of cell biology and neuroscience at the University of California, Riverside and the lead author of the study. “Children and the elderly are especially vulnerable to third-hand smoke and its impact on health. Because infants frequently crawl on carpets and touch objects exposed to exhaled smoke, they are at high risk for third-hand smoke exposure. The elderly are at high risk simply because older organs are more susceptible to disease.” Martins-Green explains that third-hand smoke consists of tobacco smoke toxins that linger on surfaces and in dust after tobacco has been smoked. “This includes toxins that become increasingly toxic with age and are re-emitted into the air or react with other chemicals in the environment to produce new pollutants,” she says. “Some of these pollutants are carcinogenic.” Previous research in mice has shown third-hand smoke to also damage the liver and lungs, complicate wound healing and cause hyperactivity.

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