Gene-editing damages DNA more than thought: study

Agencies
July 17, 2018

Paris, Jul 17:  A revolutionary gene editing technique hailed as the future of disease eradication and mooted for a Nobel Prize may be less precise and cause more cell damage than previously thought, researchers said Monday.

Lab experiments using mouse and human cells revealed that the CRISPR-Cas9 technique "frequently" caused "extensive" gene mutations, a study team reported.

"This is the first systematic assessment of unexpected events resulting from CRISPR-Cas9 editing," said Allan Bradley of the Wellcome Sanger Institute in England, where the team conducts research.

The research showed that "changes in the DNA have been seriously underestimated before now," said Bradley, who co-authored a study published in the journal Nature Biotechnology.

The mutations have not been shown to be harmful, nor benign.

"It is important that anyone thinking of using this technology for gene therapy proceeds with caution and looks very carefully to check for harmful effects," Bradley said in a statement issued by the institute.

First unveiled about six years ago, CRISPR-Cas9 allows scientists to insert, remove and correct a faulty sequence on a strand of DNA in a cell with pinpoint precision.

It has raised hopes that one-day disease-causing genes could be removed or altered before a baby is even born.

In recent years, CRISPR-Cas9 has repeatedly been predicted to win the Nobel Chemistry Prize.

CRISPRs -- clustered regularly interspaced short palindromic repeats -- are part of the immune defence system in bacteria, used to hone in on the exact spot on the genome where the cut should be made.

Cas9 is a protein used as "scissors" to snip through the faulty gene, which is then replaced or fixed by the cell's own DNA repair mechanism.

The technique's safety has not yet been proven, and it is not approved for use in human therapy.

So far, researchers have used it to improve hearing in mice going deaf and to fix a disease-causing mutation in cloned, early-stage human embryos.

But the new finding raises "safety implications," the team said.

They found "large genetic rearrangements such as DNA deletions and insertions" in cells, which could lead to important genes being switched on or off and causing dangerous changes.

The research also showed that standardized tests do not pick up damage to DNA caused by CRISPR-Cas9.

Experts not involved in the study said it was unclear how such large, unintended changes were not noticed before.

But, "the results give no reason to panic or to lose faith in the methods when they are carried out by those who know what they are doing," said Robin Lovell-Badge of The Francis Crick Institute, a biomedical research centre in London.

For Francesca Forzano, a consultant in clinical genetics and genomics with the Guy's and St Thomas' NHS Foundation Trust, the work showed that CRISPR-Cas9 "is much less safe than previously thought" and that safety-monitoring techniques were "not entirely adequate".

More research is needed before any clinical application of the method is considered, said Forzano.

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News Network
February 4,2020

Toronto, Feb 4: People who text while walking face a higher risk of an accident than those listening to music or talking on the phone, a study has found.

The study, published in the journal Injury Prevention, found that smartphone texting is linked to compromised pedestrian safety, with higher rates of 'near misses', and failure to look left and right before crossing a road.

Researchers from the University of Calgary in Canada call for a more thorough approach to exploring the impact of distracted pedestrian behaviours on crash risk.

Worldwide, around 270,000 pedestrians die every year, accounting for around a fifth of all road traffic deaths, according to the researchers.

'Pedestrian distraction' has become a recognised safety issue as more and more people use their smartphones or hand held devices while walking on the pavement and crossing roads, they said.

The researchers looked for published evidence to gauge the potential impact on road safety of hand-held or hands-free device activities.

This included talking on the phone, text messaging, browsing and listening to music.

From among 33 relevant studies, they pooled the data from 14 -- involving 872 people -- and systematically reviewed the data from another eight.

The analysis showed that listening to music wasn't associated with any heightened risk of potentially harmful pedestrian behaviours.

Talking on the phone was associated with a small increase in the time taken to start crossing the road, and slightly more missed opportunities to cross the road safely.

The researchers found that text messaging emerged as the potentially most harmful behaviour.

It was associated with significantly lower rates of looking left and right before or while crossing the road, and with moderately increased rates of collisions, and close calls with other pedestrians or vehicles, they said.

Texting also affected the time taken to cross a road, and missed opportunities to cross safely, but to a lesser extent, according to the researchers.

The review of the eight observational studies revealed that the percentage of pedestrians who were distracted ranged from 12 to 45 per cent, they said.

It also found behaviours were influenced by several factors, including gender, time of day, solo or group crossing, and walking speed.

The researchers acknowledge "a variety of study quality issues" which limit the generalisability of the findings.

"Given the ubiquity of smartphones, social media, apps, digital video and streaming music, which has infiltrated most aspects of daily life, distracted walking and street cross will be a road safety issue for the foreseeable future," the researchers noted.

"And as signage and public awareness campaigns don't seem to alter pedestrian behaviour, establishing the relationship between distracted walking behaviour and crash risk is an essential research need," they said.

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Agencies
February 26,2020

Feb 26: While too much stress can be toxic to your health, a new study suggests that despite its negative side effects, it may also lead to a surprising social benefit.

The research, published in the journal Stress & Health, found that experiencing stress made people both more likely to give and receive emotional support from another person.

This was true on the day they experienced the stressor as well as the following day.

"Our findings suggest that just because we have a bad day, that doesn't mean it has to be completely unhealthy," said study researcher David Almeida from Penn State University in the US.

"If stress can actually connect us with other people, which I think is absolutely vital to the human experience, I think that's a benefit. Stress could potentially help people deal with negative situations by driving them to be with other people," Almeida added.

For the study, the researchers interviewed 1,622 participants every night for eight nights. They asked the participants about their stressors and whether they gave or received emotional support on that day.

Stressors included arguments, stressful events at work or school, and stressful events at home.

The researchers found that on average, participants were more than twice as likely to either give or receive emotional support on days they experienced a stressor.

Additionally, they were 26 per cent more likely to give or receive support the following day.

The researchers said that while this effect, on average, was found across the participants, it differed slightly between men and women.

"Women tended to engage in more giving and receiving emotional support than men," said study researcher Hye Won Chai.

"In our study, men were also more likely to engage in emotional support on days they were stressed, but to a lesser extent than women," Chai added.

The researchers said they were surprised that stress was linked to people not just receiving emotional support, but giving it, as well.

"We saw that someone experiencing a stressor today actually predicted them giving emotional support the next day," Almeida said.

"This made me think that it's actually possible that stress helps to drive you to other people and allows it to be ok to talk about problems -- your problems, my problems," Almeida added.

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Agencies
January 11,2020

Europe, Jan 11: Researchers have revealed the people who drink tea at least three times a week have healthy years of life and longer life expectancy.

The research was published in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).

Dr Xinyan Wang, who is the author of the study, said: "Habitual tea consumption is associated with lower risks of cardiovascular disease and all-cause death. The favourable health effects are the most robust for green tea and for long-term habitual tea drinkers."
The analysis that was conducted included about 100,902 participants of the China-PAR project2 with no history of heart attack, stroke, or cancer.

Participants were classified into two groups: Habitual tea drinkers and never or non-habitual tea drinkers and followed-up for a median of 7.3 years.

The analyses estimated that 50-year-old habitual tea drinkers would develop coronary heart disease and stroke 1.41 years later and live 1.26 years longer than those who never or seldom drank tea. Compared with never or non-habitual tea drinkers, the habitual tea consumers had a 20 per cent lower risk of incident heart disease and stroke, 22 per cent lower risk of fatal heart disease and stroke, and 15 per cent decreased risk of all-cause death.

The potential influence of changes in tea drinking behaviour was suspected in a subset of 14,081 participants with assessments at two-time points. The average duration between the two surveys was 8.2 years, and the median follow-up after the second survey was 5.3 years.

Habitual tea drinkers who maintained their habit in both surveys had a 39 per cent lower risk of incident heart disease and stroke, 56 per cent lower risk of fatal heart disease and stroke, and 29 per cent decreased risk of all-cause death compared to consistent never or non-habitual tea drinkers.

Senior author Dr Dongfeng Gu said: "The protective effects of tea were most pronounced among the consistent habitual tea drinking group. Mechanism studies have suggested that the main bioactive compounds in tea, namely polyphenols, are not stored in the body long-term. Thus, frequent tea intake over an extended period may be necessary for the cardioprotective effect."

In a subanalysis by type of tea, drinking green tea was linked with approximately 25 per cent lower risks for incident heart disease and stroke, fatal heart disease and stroke, and all-cause death. However, no significant associations were observed for black tea.
Dr Gu noted that a preference for green tea is unique to East Asia.

Two factors may be at play. First, green tea is a rich source of polyphenols which protect against cardiovascular disease and its risk factors including high blood pressure and dyslipidaemia. Black tea is fully fermented and during this process, polyphenols are oxidised into pigments and may lose their antioxidant effects. Second, black tea is often served with milk, which previous research has shown may counteract the favourable health effects of tea on vascular function.

Gender-specific analyses showed that the protective effects of habitual tea consumption were pronounced and robust across different outcomes for men, but only modest for women. Dr Wang said: "One reason might be that 48 per cent of men were habitual tea consumers compared to just 20 per cent of women. Secondly, women had a much lower incidence of, and mortality from, heart disease and stroke. These differences made it more likely to find statistically significant results among men."

She said: "The China-PAR project is ongoing, and with more person-years of follow-up among women the associations may become more pronounced."

In conclusion, the authors have found that randomised trials are required to validate the results and to illustrate nutritional guidelines and advice for lifestyle.

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