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Wellcome Trust Research Round-up: 04.04.16

4 Apr, 2016

Our fortnightly round-up of news from the Wellcome Trust research community.

An apple a day

B0007586 Vitamin C

Increasing the amount of fruit and vegetables we eat may significantly reduce the progression of cataracts, a common condition affecting vision.

In a 10-year study that tracked 324 pairs of twins, Wellcome Trust-funded researchers found that a higher intake of vitamin C was associated with a 33% reduction in the risk of cataract progression.

Cataracts form when the lens in the eye becomes oxidised over time, resulting in cloudy eyes. The condition is often associated with ageing, and surgeons perform over 300,000 procedures a year to replace damaged lenses.

Scientists tracked the diets of the twins throughout the study and analysed photographs of their eyes for signs of cataracts.

The fluid that baths our eyes, preventing oxidation is high in vitamin C, and researchers believe that increasing dietary intake of this vitamin may protect the lens by increasing the levels present in this fluid.

The findings, published in Ophthalmology, suggest a greater role for environmental factors rather than genetic factors in cataracts.

Professor Chris Hammond from Kings College London said: “The findings of this study could have significant impact, particularly for the ageing population globally by suggesting that simple dietary changes such as increased intake of fruit and vegetables as part of a healthier diet could help protect them from cataracts.”

Understanding chromosomal abnormalities

B0000046 Mouse embryo confocal

Early embryos with genetic abnormalities may still be capable of developing into healthy babies according to new research in mice, published in Nature Communications.

Chromosome abnormalities can cause a range of developmental disorders, including Down’s syndrome, with babies born to older mothers being especially at risk. Currently, expectant mothers are offered genetic testing to detect abnormal placental cells, but geneticists have limited understanding of the fate of embryos with these abnormalities.

Wellcome Trust-funded researchers from the University of Cambridge used mouse models to investigate the fate of embryos with an unusual number of chromosomes (instead of the normal 23 pairs) in some of the cells of the placenta. They found that mouse embryos with a mix of half normal and half abnormal cells developed into fully healthy embryos with all normal cells. The researchers observed that the abnormal cells were killed through programmed cell death, or apoptosis, to remove all cells with chromosome abnormalities.

“The embryo has an amazing ability to correct itself,” explains Professor Zernicka-Goetz. “We found that even when half of the cells in the early stage embryo are abnormal, the embryo can fully repair itself. If this is the case in humans, too, it will mean that even when early indications suggest a child might have a birth defect because there are some, but importantly not all abnormal cells in its embryonic body, this isn’t necessarily the case.”

Blocked up immune cells

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Smoking can cause our immune cells to get ‘clogged up’, increasing the risk of contracting tuberculosis (TB) and making the infection worse.

In a new study published in Cell, Wellcome Trust-funded researchers used zebrafish to study a type of immune cell called a macrophage. These specialised cells are our body’s first line of defence against Mycobacterium tuberculosis, engulfing the bacteria and destroying it using enzymes.

As well as destroying bacteria, macrophages also play a key role the body’s ‘housekeeping’ by recycling and removing unwanted material. It is this function that, when disrupted, can cause them to get ‘clogged up.’

The team studied genetic variants associated with increased risk of TB, identifying a variant that can prevent the cell’s housekeeping function. Without this essential activity, macrophages became large and slow, and were unable to move around to destroy bacteria.

Wellcome Trust Principal Research Fellow Professor Lalita Ramakrishnan from the University of Cambridge said: “Macrophages act a bit like vacuum cleaners, hoovering up debris and unwanted material within the body, including the billions of cells that die each day as part of natural turnover. But the defective macrophages are unable to recycle this debris and get clogged up, growing bigger and fatter and less able to move around and clear up other material.”

When the researchers examined the macrophages of smokers, they found that they were blocked with smoke particles which also caused them to be large and slow. The findings explain why smoking increases the risk of getting TB, because smoke particles also prevent macrophages from effectively removing the TB bacterium, in a similar way to those cells with the disrupted housekeeping function.

Other Wellcome Trust research news

Researchers at the Wellcome Trust-funded Mahidol Oxford Tropical Medicine Research Unit are studying the accuracy and cost-effectiveness of different tests to diagnose non-malarial fevers in rural settings. They found that testing for the biological markers of inflammation, rather than specific pathogens, gave a better indication of which patients required antibiotics. The team hope the results will inform a more robust approach to managing antibiotic use in rural settings to help slow the spread of drug resistance. This research was published in PLOS ONE.

Researchers from the Wellcome-Trust funded Mahidol Oxford Tropical Medicine Research Unit and the Oxford University Clinical Research Unit in Vietnam have recommended a more population-based approach to the prevention of drug resistance in malaria. In an article in PLOS Medicine, the researchers called for national and international health policy action to preserve the effectiveness of the drug artemisinin for as long as possible.

In other news

Congratulations to Professors Peter Horby and Heiman Wertheim who were awarded the Vietnam Ministry of Health’s Medal for the People’s Health. Both Professors are previous directors of the Wellcome Trust-funded Oxford University Clinical Research Unit, Hanoi and the medal recognises their major contribution to health in Vietnam.

Image credits: (from top to bottom) Kevin Mackenzie, University of Aberdeen. Wellcome Images; Dr David Becker. Wellcome Images; Macrophage engulfing Tuberculosis bacteria via Flickr CC-BY-NC-ND

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