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Wellcome Trust Research Round-Up: 11.01.16

11 Jan, 2016

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

A weight off your shoulders

fat cells.jpgWeight-loss surgery can reduce the risk of developing serious heart problems, according to new research published in PLOS Medicine.

Wellcome Trust-funded researchers suggest that increasing access of bariatric (weight-loss) surgery could benefit thousands of people who are classified as ‘severely obese’, with a body mass index (BMI) of at least 40kg/m2. The procedure is thought to cut the risk of heart attacks and type 2 diabetes, and stimulates significant weight loss that can be sustained for at least four years.

Researchers at the London School of Hygiene and Tropical Medicine in partnership with UCL and the UCLH Bariatric Centre for Weight Management and Metabolic Surgery compared different types of weight-loss surgery to determine which ones were most effective. Gastric bypass was identified as the most successful after a four year period, followed by sleeve gastrectomy and gastric band.

Extrapolating the findings from this study, the researchers estimated that 80,000 cases of hypertension, 40,000 cases of type 2 diabetes and 5,000 heart attacks could be prevented over a four year period.

Study co-author Professor Rachel Batterham, Head of the UCLH Bariatric Centre for Weight Management and Metabolic Surgery and the UCL Centre for Obesity Research, said: “Bariatric surgery is safe and produces unrivalled health benefits that are life-changing for patients and cost-saving for the NHS. Unfortunately, less than 1% of the patients who could benefit from this surgery currently receive surgery. This represents a major missed opportunity in terms of improving health and economic savings. Action is now needed to remedy this situation.”

Having a devil of a time

Tasmanian Devil

Credit: jomilo75

A second form of contagious cancer has been discovered in Tasmanian devils, new research from the University of Tasmania, Austrialia and the University of Cambridge, UK confirms.

The study, published in the Proceedings of the National Academy of Science, has made scientists question their current understanding of the processes that drive living cancer cells to spread between individuals and become transmissible.

Previous research conducted in the 1990s discovered contagious cancerous tumours had spread between Tasmanian devils, leading to a significant decline in the population. Transmissible cancers have been considered as very rare in nature; only two other forms have ever been seen, occurring in dogs and in soft-shell crabs.

The second form of contagious cancer in Tasmanian devils was identified in 2014, and at first appeared very similar to the first. However, scientists have now found that this second cancer is genetically distinct.

Dr Elizabeth Murchison from the Department of Veterinary Medicine at the University of Cambridge, and a senior author on the study, says, “Previously, we thought that Tasmanian devils were extremely unlucky to have fallen victim to a single runaway cancer that emerged from one individual devil and spread through the devil population by biting. However, now that we have discovered that this has happened a second time, it makes us wonder if Tasmanian devils might be particularly vulnerable to developing this type of disease, or that transmissible cancers may not be as rare in nature as we previously thought.”

Darwin’s puddle

Cichlid fish

Credit: Brian Gratwicke

New species can evolve even when there is no geographic or physical barrier to separate old and new species from constant genetic mixing researchers from the Wellcome Trust Sanger Institute have discovered.

The process, known as ‘sympatric’ speciation, has been much debated in evolutionary biology, with some questioning whether it’s even possible. This research marks an exciting development as scientists have – for the first time – observed this form of evolution in cichlid fish living in Lake Massoko, a tiny volcanic crater late in Tanzania.

Researchers identified two different forms (‘ecomorphs’) of cichlid fish that were separating from each other in the 700m-wide lake. The first – known as littoral – are yellow-green and male, living near the lake’s shores. The other form – benthic – are dark-blue and male, living deeper under the surface where there is less light. Genetic differences between the ectomorphs revealed that most of the variation was in genes associated with sight, hormone signalling, size and shape.

However, no single factor (either physical or genetic) seems to separate the two ecomorphs. While they prefer to live at different depths, they are often found in close proximity. Researchers undertook mate-choice experiments in a controlled laboratory to investigate whether sexual selection can reinforce differences via mate preference. While some differences were found, there were not enough to explain the separation.

In contrast to Lake Malawi, which is referred to as ‘Darwin’s Pond’ due to the hundreds of cichlid species identified, Lake Massoko has been dubbed ‘Darwin’s puddle’, with far fewer species and factors to drive speciation.

First author Dr Milan Malinsky of the Wellcome Trust Sanger Institute and the Gurdon Institute, University of Cambridge said: “One of the most striking characteristics of this diversification is that less than 1 per cent of the genome appears to be involved.  Previous expectations were that speciation involved changes across the whole genome.  However, in this example of nascent sympatric speciation, we find that the differences are confined to localised regions of the genome – known as genomic islands – that are associated with specific traits.”

In other news…

A recent Wellcome Trust-funded study suggests an antiretroviral treatment could prevent almost two-thirds of new HIV infections in gay and bisexual men in the Netherlands. The research, published in Science Transational Medicine, makes the case for this treatment (known as pre-exposure prophylaxis) to become more widely available in Europe.

Ratmann_ScienceTM_2015Jan06_HIVNLFactsheet_English_figure_2

Credit: Ratmann et al.

Congratulations to scientists at icddr,b, an international public health research institution in Bangladesh, who have being awarded a major research grant to study ways to manage hypertension in rural South Asia. The research is funded by the joint global health trials scheme, a partnership between the UK’s Department of International Development, the Medical Research Council and the Wellcome Trust.

B0006057 Anopheles stephensi full of blood

Credit: Hugh Sturrock. Wellcome Images

MediSieve, the developer of a magnetic filter device that captures and removes red blood cells infected with malaria, has received a Pathfinder Award from the Wellcome Trust. The funding will be used to manufacture and test clinical prototypes of its device, and aims to prove the device is safe for use on human patients.

Professor John Edmunds, Dean of Faculty of Epidemiology & Population Health at the London School of Hygiene and Tropical Medicine and member of the Wellcome Trust’s Population and Public Health Expert Review Group, has been awarded an OBE in the Queen’s New Year Honours list for his services to infectious disease control.

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