Gene drives can beat pests, but we can’t afford any mistakes

Possum against a dark background

Possums are protected in Australia but reviled in New Zealand

Thorsten Milse /Robert Harding/Getty

Pest control can sometimes get out of hand. In 1995, Australia was testing the deadly calicivirus for controlling rabbits on an island. Somehow the virus escaped and spread across the entire country.

New Zealand, which also has a serious rabbit problem, decided not to introduce the virus. But a group of farmers took it upon themselves to smuggle the virus into the country in 1997, where it still circulates today.

Now New Zealand is considering using genetic “extinction” drives to tackle invaders such as rats, possums

To continue reading this premium article, register or login for free for unlimited access. Existing users, please log in.

Common condition endometriosis reprograms brain for depression

A woman on a hospital bed

Women with endometriosis can experience anxiety as well as pain

Michele Constantini/Getty

Endometriosis can reprogram the brain, causing anxiety and depression – according to research in mice. The findings suggest the common disorder may put the one in ten women who have it at risk of mental health problems.

Endometriosis is caused by uterus lining (endometrium) cells moving elsewhere in the body where they can compress nerves and bleed in time with a woman’s menstrual cycle. It affects 176 million women worldwide and can cause severe pain as well as infertility.

But despite being a common disorder among women of reproductive age, we know very little about it. What causes bits of a women’s uterine lining to turn up elsewhere in the body remains mysterious, but one theory is that menstrual blood somehow moves up through the pelvis, carrying tiny bits of tissue into other organs as it

Medical cannabis vendors must stop making bogus health claims

A pot of medical cannabis on a table

A pot of pot

Portland Press Herald/Getty

Cannabis can make scars disappear, reverse Alzheimer’s disease and even cure cancer – that is, if you believe some of the wilder health claims made by US firms in states where medical marijuana has been legalised.

Unfortunately, such assertions aren’t based on a shred of good evidence. Not only are consumers being ripped off, but sometimes their health is being endangered. Little wonder that the US cannabis industry is sometimes dubbed a Wild-West operation.

Although marijuana is best known as a recreational drug that gets you high, the plant has a long

To continue reading this premium article, register or login for free for unlimited access. Existing users, please log in.

Daytime injuries heal twice as fast as wounds sustained at night

Microscope image of fibroblasts

Healing cells are more active during daytime

VSHYUKOVA / SCIENCE PHOTO LIBRARY

If you’re going to get injured, try to do it during the day. Wounds seem to heal twice as fast if sustained during daytime hours rather than at night.

Nathaniel Hoyle of the Laboratory of Molecular Biology in Cambridge, UK, and his team have been investigating how the time of day affects wound healing, after they discovered that genes in a type of skin cell switch on and off during day-night cycles. These cells, called fibroblasts, help close up a wound after the skin has been cut, and some of the genes whose activity varied throughout the day were ones that help control this process.

Surprised by these day-night changes in gene activity, the team decided to analyse data collected by a specialist burn injuries unit at the University of Manchester, UK. They found that, on average, daytime wounds healed much faster – in only 17 days, compared with 28 days for similar burns sustained at night.

Advertisement

“We found that how well you heal depends on what time of the day you’re injured,” says Hoyle. “Healing in the day can occur 60-per-cent faster.”

Cells on the move

Following a cut to the skin, fibroblast cells rush to the wound and secrete a matrix that helps skin cells move into place, grow, and heal the injury. Before turning to the burns data, the team first discovered in experiments with mouse tissue that fibroblasts arrive at the site of a new wound twice as quickly during a mouse’s usual waking period than during its sleep period.

This seems to be because a group of around 30 genes are more active during waking hours. These genes all help control actin, a protein used by fibroblast cells to move.

Hoyle’s team think healing may be linked to circadian rhythm in mammals because we’re more likely to be injured during the active part of our day. The finding might be useful medically, says Hoyle. If drugs can fool injury sites into a “daytime” status, they might heal more quickly, for example.

“This research adds to the accumulating evidence that ‘time of day’ or ‘circadian rhythmicity’ matters in medicine,” says Derk-Jan Dijk, of the University of Surrey, UK. “The question is how we can make use of this knowledge, and whether it can change clinical practice and help patients.”

Journal reference: Science Translational Medicine, DOI: 10.1126/scitranslmed.aal2774

Gluten-sensitive? It may actually be a carb making you ill

Gluten-free foods

Have we had the wrong culprit all along?

Jesper Mattias/Getty

Gluten might not be the bad guy after all. Evidence suggests it may be the fructan molecules in wheat that cause stomach problems in people with an intolerance.

About 1 per cent of people have coeliac disease, an autoimmune disorder that makes them react badly to gluten proteins in wheat. But a further 12 per cent feel ill after eating wheat-based foods like bread and pasta, despite not having coeliac disorder.

Now it looks like it may not actually be gluten that causes problems for these people with “gluten sensitivity”.

Advertisement

In 2013, a study of non-coeliacs who ate gluten-free to relieve gut issues found no difference in symptoms when these people ate identical meals that either lacked gluten, or were full of it. This suggested gluten has no effect, prompting Jane Muir and Peter Gibson at Monash University in Australia and their team to wonder if there might be an alternative culprit.

Separating the wheat from the chaff

They suspected fructans, which are a type of sugar chain found in wheat, barley and rye, as well as onions, garlic, chickpeas, cabbage, and artichokes.

To test this, they recruited 59 non-coeliac adults currently following gluten-free diets for gut sensitivities. They gave these volunteers three types of cereal bars containing gluten, fructans, or neither, and the participants ate one of these every day for seven days, with week-long spaces in-between each type of bar. The bars all looked and tasted the same, and the participants did not know which ones they were eating.

The fructan bar triggered 15 per cent more bloating and a 13 per cent increase in overall gastrointestinal symptoms, compared to the control bar. The gluten bar, however, had no effect.

This may explain why people with irritable bowels often improve on gluten-free diets but don’t make a full recovery, says Muir. By cutting out wheat, they eliminate a large portion of fructans from their diets, but they can still run into trouble eating other high-fructan foods like onions and garlic. Some gluten-free products like chickpea crisps also contain fructans.

It may also explain why few placebo-controlled studies have managed to find that gluten has any effect, and why it has been so difficult to find out how gluten may cause problems for non-coeliacs, says Gibson.“Gluten was originally assumed to be the culprit because of coeliac disease, and the fact that people felt better when they stopped eating wheat,” he says. “Now it seems like that initial assumption was wrong.”

It’s possible that a small minority of non-coeliacs do react to gluten and studies so far haven’t been big enough to readily detect them, Gibson says. “But certainly the evidence points to fructans being more of a problem.”

Difficult to digest

The team’s findings fit with six recent trials that suggest about 70 per cent of people with irritable bowel syndrome feel better when they cut out fructans and other nutrients from a food group known as FODMAPs.

This stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. These are a collection of short sugar chains that are difficult to digest. They draw in water and are fermented in the large intestine by gas-producing bacteria, causing the gut to stretch slightly. People with irritable bowel syndrome are more aware of this because they have hypersensitive nerve endings in their guts.

Katie Ellard, a gastroenterologist at Mater Hospital in Sydney, Australia, says many clinicians are now prescribing low-FODMAP diets to people with stomach troubles. “Once coeliac disease has been ruled out, I still recommend knocking off wheat to see if that helps, but I explain that it’s to eliminate fructans not gluten from their diet,” she says.

If fructans do turn out to be the real problem, it will open up a range of foods that were previously off-limits, says Ellard. Soy sauce, for example, contains gluten but is low in fructans, while the fermentation process used to make sourdough bread strips away wheat’s fructans.

Journal reference: Gastroenterology, DOI: 10.1053/j.gastro.2017.10.040

Read more: Should you eat wheat? The great gluten debate

More on these topics:

State of unrest: Can fidgeting really help you concentrate?

girl and hair

Is everybody concentrating?

Vladimir Godnik/Plainpicture/fStop

I WONDER whether you will stay completely still until you reach the end of this article. If you do, then perhaps I have done a good job – fidgeting, as you might expect, is a pretty reliable indicator of waning attention.

But is there more to it? For those incessant pen-clickers, hair-twirlers and foot-tappers among us, the urge to fidget is irresistible. The popularity of the fidget spinner is a case in point: earlier this year, variants of it made up every one of the top 10 bestselling toys on Amazon. Many of these gadgets come with claims they can help children with ADHD (attention deficit hyperactivity disorder), anxiety or autism. Some people say fidgeting aids focus, or could even boost efforts to lose weight. So should we all harness the powers of restlessness?

Our interest in the subject has a long history. In 1885, the polymath Francis Galton – a cousin of Darwin – found himself in such a tedious meeting that he measured the amount of fidgeting in the audience, publishing his findings in Nature. Freud ascribed deeper meaning to fidgeting, interpreting it as a manifestation of sexual problems. And then in the 1950s, when “hyperkinetic disorder” – later ADHD – came to prominence, fidgeting began to be seen as a pathological symptom.

Underlying the claim that fidget spinners can help boost attention in those with ADHD, especially children, is the idea that the disorder is associated with chronic under-arousal at a neural level. This hampers mental performance, but the thinking is that movement can compensate by stimulating the neurotransmitters associated with arousal. “When I watched

How social stress makes your brain vulnerable to depression

A woman in a dark room

Changes in your brain can be brought on by stressful situations

Gordon Spooner/Plainpicture

Social stress can trigger changes in the brain that open the door to depression. Experiments in human brains and mice suggest that experiences such as bullying make the blood-brain barrier leaky, letting inflammation into the brain and altering mood.

Anything that threatens your sense of worth is a type of social stress – be it bullying, body-image issues, social anxiety or extreme shyness. To see how such stresses might affect mood, Scott Russo of the Icahn School of Medicine at Mount Sinai, New York, and his team exposed 24 small, subordinate mice to larger, dominant mice for 10 minutes every day, for 10 days. Ten of the mice coped well with this, but 14 became socially withdrawn and more timid.

Comparing blood, DNA and tissue samples from the stressed small mice, nine control mice and mice that were more relaxed in the presence of big bruisers suggests that there are three stages in the process of social stress leading to an altered mood. First, the stress kicks off inflammation in the bloodstream. This then weakens the blood-brain barrier, which normally protects the brain, making it leaky and more likely to let substances through into the brain.

Advertisement

This enables large molecules like inflammatory substance interleukin-6 and aggressive white blood cells called monocytes to pass into the brain. Here they seem to disrupt signalling in the nucleus accumbens, a part of the brain that helps evaluate threats and rewards.

Change of mood

This is the first study to link social stress to blood-brain barrier dysfunction and depression-related behaviour, says Russo.

In stressed mice, up to 30 per cent of vessels lining the blood-brain barrier showed signs of breaches in the nucleus accumbens. This seems to be caused by changes in gene activity – in stressed mice, genes in this brain area produced 40 per cent less of a protein called claudin-5, which usually secures the integrity of the blood-brain barrier.

When the team examined post-mortem human brain tissue from 39 people who’d had depression, and 24 people who hadn’t, they found that levels of claudin-5 in the nucleus accumbens of many of the people who had had depression were around 50 per cent lower.

“The study cements the central role of inflammation in the genesis of mood disorders,” says Michael Berk of the University of Melbourne in Australia. “It also explains a critical element of the puzzle –the mechanisms whereby stress can influence the brain via inflammation.”

Russo says the study suggests new avenues for treating depression. One option would be to use an antibody called sirukumab to remove interleukin-6 from the blood, so that it can’t reach the brain. Previous work by Russo’s team has found that people with depression can have as much as 100 times more interleukin-6 in their blood than people who aren’t depressed.

Sirukumab is already being tested in people with depression, but other strategies may work too. One could be to shore-up the blood-brain barrier, making it less likely to let inflammatory molecules through, or reducing the level of monocytes in the blood. If approaches like this could work, they may help protect people in difficult circumstances – such as a hostile work environment or a stressful family situation – from developing depression.

Journal reference: Nature Neuroscience, DOI: 10.1038/s41593-017-0010-3

Read more: Having an overactive immune system may prime you for depression

More on these topics:

Coffee and plant-based diets linked to lower heart failure risk

A woman eating salad

Salad with a side of coffee

d3sign/Getty

Less meat, more coffee. That’s the secret to reducing your risk of heart failure, according to two studies.

Heart failure is a progressive condition in which the heart cannot pump as much blood as the body needs. This results in less oxygen and nutrients being delivered to the rest of the body, and can lead to death.

Kyla Lara at Mount Sinai Hospital in New York and her team have analysed data on diet and heart health from more than 15,000 people over the age of 45. They found that people who had been previously diagnosed with heart disease or heart failure were 28 per cent less likely to be subsequently hospitalised for heart failure if they ate a diet consisting mostly of fruit, vegetables, beans, whole grains, and some fish, when compared with people who ate mainly meat and processed foods.

Advertisement

The findings, presented at a meeting of the American Heart Association in Anaheim, California, today, were observational, and couldn’t show cause-and-effect, but they fit with other research, says Lara. “People who eat more plant-based foods eat less processed foods and therefore have less sodium intake, which has been shown to increase risk for high blood pressure and heart failure,” she says.

Caffeine hit

The meeting today also heard that drinking coffee is associated with a lower risk of heart failure.

In an analysis of more than 17,000 adults aged 44 and older, Laura Stevens at the University of Colorado and her team found that coffee-drinkers seem to have a 7 per cent lower risk of developing heart failure for every cup of coffee they consume per week, compared with non-coffee drinkers.

It is unclear why coffee would cut the risk of heart failure, says Stevens. “We don’t yet know if it is the coffee intake itself or another behaviour that might go along with it,” she says. For example, coffee-drinkers may simply have healthier lifestyles.

The findings are supported by two other studies published earlier this year that found that coffee-drinking seems to significantly reduce the chance of dying from heart disease.

More on these topics:

NHS reforms have failed to boost community-based care in England

GettyImages-556634653

Reorganising the National Health Service in England has failed to increase the amount of care taking place in the community.

The health service changed radically in England in 2013, when two-thirds of the NHS budget was transferred to family doctors. The hope was that more people could be treated relatively cheaply locally, rather going for assessment or treatment at hospitals.

Advertisement

But a study has found that the rate of people going into hospital between 2013 and 2015 has remained static. By the end of 2015, the number of referrals to specialists had increased by 19 per cent. Rates of hospitalisation and referrals were unaltered in Scotland, where no reforms took place.

“It’s hard to say whether the policy as a whole is a failure,” says James Lopez Bernal of the London School of Hygiene and Tropical Medicine. “But we know that the idea was to shift more care into the community, and our findings suggest that’s not been happening.”

Journal reference: PLOS Medicine, DOI: 10.1371/journal.pmed.1002427

This article appears in print under the headline “NHS plan backfires”

More on these topics:

How long should you let a pregnancy run before being induced?

A newborn baby

Safer to be born at 40 weeks

Kohei Hara/Getty

If your pregnancy runs past its due date, how long should you wait before being induced? Evidence is building that, at least for older women, it’s safer to get the baby out on time, at 40 weeks.

This seems to be the case for first-time mums, according to a review of 80,000 women in England. Gordon Smith of the University of Cambridge and his colleagues found that when women aged 35 or older are induced at 40 weeks, only 0.08 per cent of their babies died. But in women who waited until they gave birth naturally, or who were induced at 41 to 42 weeks, this rose to 0.26 per cent.

This means that, for every 562 women who were induced at 40 weeks, one stillbirth was avoided.

Advertisement

Failing placenta

After a certain point, the longer a pregnancy continues, the more likely it is that a baby will die unexpectedly in the womb – probably because it gets too big to be supported by a deteriorating placenta. By 40 weeks, the placenta is beginning to fail, says Smith.

Birth can be triggered with medicines that open the cervix and bring on contractions, but this tends to make labour longer and more painful. Induction is currently recommended in the UK if a woman has gone overdue by one to two weeks, regardless of her age.

The team found that earlier inductions tended to have a slightly higher rate of emergency Caesarean sections and the use of instruments like forceps. But this could have been because women with complications were more likely to be induced early, says Smith.

Last year a randomised trial found inducing over-35s even earlier, at 39 to 40 weeks, made no difference to the rate of C-sections or instrumental deliveries.

Making a choice

Smith says women should be told about the pros and cons of induction and offered a choice. “The absolute risk [of waiting] is small. For some women it’s acceptable in the context of prioritising a natural approach. For others it’s unacceptable.”

Women are tending to have children later in life in the UK, says Hannah Knight of the London School of Hygiene and Tropical Medicine, who also worked on the study. About one in seven first-time mothers were 35 or older in England and Wales in 2015.

Smith says younger women might also consider an earlier induction based on these findings. “It’s self-evident that if you deliver the baby at 40 weeks, it cannot be stillborn at 41 weeks.”

Journal reference: Plos Medicine, DOI: 10.1371/journal.pmed.1002425

More on these topics: