Saturday 19 January 2013

Leprosy bacteria use 'biological alchemy'


Infectious bacteria have for the first time been caught performing "biological alchemy" to transform parts of a host body into those more suited to their purposes, by a team in Edinburgh.
The study, in the journal Cell, showed leprosy-causing bacteria turning nerves into stem cells and muscle.
The authors said the "clever and sophisticated" technique could further therapies and stem-cell research.
Experts described the discovery as "amazing" and "exciting".
Alchemists may have failed to morph base metals into gold, but a team at the University of Edinburgh has shown that bacteria can transform parts of the body into something more valuable to them.
It is a feat that scientists have already achieved in the laboratory. Skin cells have been transformed into flexible stem cells that can become any of the body's building blocks from heart muscle to brain cells.
One of the researchers, Prof Anura Rambukana, said: "Our body's cells can be manipulated and why would a bacterium not take advantage of that?"
Master manipulators
Experiments on mice and cells grown in the laboratory showed the leprosy bug infected nerve cells. Then over a period of a few weeks the bacteria began to subvert the nerves for their own ends. The chemistry of the cells changed and they became stem cells.

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The ability of bacteria to convert one mammalian cell type to another is 'alchemy' by nature on a grand scale”
Prof Chris MasonStem cell scientist
These can grow and spread around the body, unlike the static nerves.
"This is a stem cell that is generated by the body's own tissue so the immune system does not recognise it and they can get any place they want without being attacked," said Prof Rambukana.
Those cells could lodge inside muscle and become muscle cells.
"We realised, 'Wow, this is something very, very striking'.
"It's the first time a bacterial infection has been shown to make stem cells, that's the big thing here."
'Alchemy'
He hopes the findings will increase understanding of leprosy and lead to new ways of developing stem cells - which have been touted as future treatments for a range of diseases.
Prof Rambukana also believes it is "probable" that other species of bacteria would have evolved the same ability to reprogramme their host.
Prof Chris Mason, a specialist in stem cell research at University College London, said: "The ability of bacteria to convert one mammalian cell type to another is 'alchemy' by nature on a grand scale.
"Whilst this amazing discovery is in a mouse model, it highlights the extraordinary complexity of the interactions between mammals and bacteria and the ingenuity of scientists to uncover disease mechanisms that a decade ago would have been beyond science fiction.
"The next essential step is to translate this valuable piece of knowledge into tangible benefits for patients - a process that may take a decade before its relevance to clinical medicine is fully understood."
Prof Diana Lockwood, from the London School of Hygiene and Tropical Medicine, said: "Their finding that bacteria can reprogramme cells is very interesting and exciting."
However, she cautioned that there was "quite a gap between this and clinical leprosy and I don't think it's going to lead to new treatments".
Dr Rob Buckle, head of regenerative medicine at the Me Redical Research Council, said: "This discovery is important not just for our understanding and treatment of bacterial disease, but for the rapidly progressing field of regenerative medicine."
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Weight loss 'is body's way of fighting off gut worms'


Weight loss following infection with intestinal worms is the body's way of fighting off the parasites, University of Manchester researchers have said.
The immune system hijacks a hormone that controls when to stop eating, their study of mice suggests.
This then triggers the type of immune response needed to expel the worms from the gut, PLOS Pathogens reports.
The finding could lead to new ways to treat people with intestinal worms, researchers say.
Researchers first saw a potential link when they were measuring levels of a hormone called cholecystokinin in volunteers after they had been fed a meal.
One man had incredibly high levels and on further investigation it was found he had an intestinal worm infection he had picked up on holiday.
Joining forces with a team specialising in gut worm infections the researchers did a study in mice infected with a worm called Trichinella spiralis.

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Naturally you would think that if you are losing weight you are going to have less energy to fight off infection.”
Dr John WorthingtonUniversity of Manchester
They found that immune cells called T-cells responded to the worm infection by driving up levels of cholecystokinin.
This increase has a knock-on effect of driving down another hunger hormone, leptin, which influences what type of immune response the body needs to produce.
When they artificially added leptin back into the infected mice, the immune system mounted the wrong response and the intestinal worms remained in the gut for longer.
Global problem
Nearly one in every four of the world's population are infected with gastrointestinal parasites.
It has long been known that these infections often result in a period of reduced appetite and weight loss but why or how this happens was not understood.
Study author Dr John Worthington said the researchers had looked at only one type of parasitic worm but were now doing tests to see if the same response was produced in response to other worms.
"Naturally you would think that if you are losing weight you are going to have less energy to fight off infection," he said.
"This does the opposite of what you would expect."
Dr Worthington added that eventually they would be looking at whether different treatment or nutrition strategies could be designed to boost this immune effect in people affected with intestinal worms.
Dr Mark Robinson, lecturer in parasite proteomics at Queen's University Belfast, said that diseases of humans and animals caused by parasitic worms were among the most widespread and economically devastating throughout the world and drug resistance was becoming a problem.
"The best way to combat worm infections in the future will be the development of vaccines which represent safer, more environmentally-friendly, alternatives to drugs," he said.
"At present, vaccine development is hampered by a lack of basic understanding of how parasitic worms interact with, and influence, our immune system, so research in this area will hope
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Monday 14 January 2013

Mum's testing affects HPV jab uptake, says survey


A mother's attitude towards cervical cancer screening influences decisions to vaccinate daughters against the cancer, researchers in Manchester say.
Data from 117,000 girls was analysed.
Teenagers were at least three times more likely to have had the HPV vaccination if their mothers had been tested in the past five years.
The study, in the European Journal of Cancer, also showed daughters were more likely to have been vaccinated if their mothers received an abnormal result.
The cervical cancer vaccine was introduced in the UK in 2008 and is offered to girls with parental consent in their second year of secondary school with catch-up campaigns in older teenagers.
It provides immunity to the sexually transmitted infection responsible for most cases of cervical cancer.
New finding
The team from the University of Manchester linked cervical screening records and HPV vaccination records in the north-east of England by address.
It is the first time such a link has been studied in the UK.
They found that the uptake of HPV vaccination among 12-13-year-olds in those whose mothers had never been screened for cervical cancer was 58%.

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"It shows there is a link within families and that targeting both mothers and daughters may have an influence on uptake of prevention programmes”
Angela SpencerUniversity of Manchester researcher
In the same age group whose mothers had been screened for cervical cancer in the past five years, the uptake was almost 84%.
Further analysis showed mothers who had personally decided to stop screening were less likely to have vaccinated their daughters than those who had stopped for medical reasons.
The researchers are now planning to carry out in-depth interviews. They want to out what influences a mother's decision to give consent for her daughter to be vaccinated and whether socio-economic factors play a part.
But they pointed out that there were important public health implications to the findings.
They said not only are teenagers of mothers not engaging with screening less likely to be vaccinated they are also less likely to engage with screening themselves when they get older, putting them at risk.
And maintaining high HPV vaccine coverage is extremely important because figures show cervical screening coverage is declining among 25-29-year-olds with some evidence of increasing cancer incidence at younger ages, they pointed out.
Family pattern
Research assistant Angela Spencer said the results suggest that a mother's attitudes and behaviour with respect to her own cervical screening attendance or to preventive programmes in general, are important determinants in her decision to vaccinate her daughter, particularly at younger ages.
She added: "It shows there is a link within families and that targeting both mothers and daughters may have an influence on uptake of prevention programmes."
Dr Claire Knight, Cancer Research UK's health information manager, said: "HPV vaccination and screening are the best ways of reducing the risk of cervical cancer.
"This study adds to our knowledge about the factors that affect vaccination behaviour, including the influence of family and friends.
"It's important to ensure all women understand the importance of HPV vaccination and cervical screening and their role in saving lives."
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Pill-sized scanner images gullet


Doctors have made a pill-sized device that can take detailed microscopic images of inside the gullet.
It is hoped the US technology could become an easier way of screening people for a condition called Barrett's oesophagus, which can lead to cancer.
Unlike current imaging techniques, the device can be used while the patient is conscious and takes only a few minutes.
The device has been tested in a small number of patients so far, Nature Medicine reports.
Although researchers at Wellman Center for Photomedicine at Massachusetts General Hospital in Boston say the device has potentially wide application, it could be particularly useful for Barrett's oesophagus where many people do not realise they have it, but there is no easy way to screen for it.
In those with the condition, the cells in the lower gullet become abnormal due to chronic acid reflux, which puts them at a higher risk of developing cancer of the oesophagus.
Doctors can screen those at risk using an endoscope - a flexible tube containing a tiny video camera - but this is unpleasant and usually has to be done under sedation.
Tiny capsule
The new device is contained in a capsule about the size of a multivitamin pill connected by a thin wire.
Within the capsule is a rapidly rotating laser tip which emits infrared light that is then reflected back from the lining of the oesophagus.

When the patient swallows the capsule it is carried down the oesophagus in the same way any piece of food would be then once it reaches the stomach it can be pulled back out using the wire.The image doctors see on the screen is a 3D landscape showing far more microscopic detail than can be seen with endoscopy.
Images are taken the whole time the device is moving up and down the gullet and the whole process takes a matter of minutes.
Testing the equipment in six patients known to have Barrett's oesophagus and seven healthy volunteers, the researchers said the images clearly showed the cellular changes that occur in those with the condition.
'Best pictures'
Prof Gary Tearney, one of the research collaborators, said the technology is cheaper than endoscopy and avoids the need for sedation, specialised equipment or special training.
And the microscopic detail shown in the images means a biopsy can be avoided.
"The images produced have been some of the best we have seen of the oesophagus," says Prof Tearne, a professor of pathology at Harvard Medical School.
"We originally were concerned that we might miss a lot of data because of the small size of the capsule, but we were surprised to find that, once the pill has been swallowed, it is firmly 'grasped' by the oesophagus, allowing complete microscopic imaging of the entire wall."
Prof Tearney added that the device could help doctors work out who is at risk and detect cancers at potentially more treatable stage.
Prof Rebecca Fitzgerald, a specialist on Barrett's oesophagus at the Cambridge Cancer Centre, said: "It is elegant technology. The downside is that you will have to endoscope anyone with suspected Barrett's as you will have no way of sampling and detecting dysplasia [abnormalities] with this technology."
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