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General interest items edited by Janice Flahiff

Complex signaling between blood and stem cells controls regeneration in fly gut

Complex signaling between blood and stem cells controls regeneration in fly gut.

 

Buck Institute scientists say impaired interactions between macrophages and stem cells are likely players in human intestinal maladies like IBS, leaky gut and colorectal cancers 

May 25, 2015/NOVATO, CA:  Having a healthy gut may well depend on maintaining a complex signaling dance between immune cells and the stem cells that line the intestine. Scientists at the Buck Institute are now reporting significant new insight into how these complex interactions control intestinal regeneration after a bacterial infection. It’s a dance that ensures repair after a challenge, but that also goes awry in aging fruit flies — the work thus offers important new clues into the potential causes of age-related human maladies, such as irritable bowel syndrome, leaky gut and colorectal cancer.

“We’ve dissected a very complex signaling interaction,” said senior scientist and Buck faculty Heinrich Jasper, PhD. “By doing so temporally we’ve clearly established a role for the immune system both in initiating the regenerative process and in shutting it down – activities that are essential for maintaining tissue homeostasis.”

Publishing in the May 25, advance online edition of Nature Cell Biology, researchers in the Jasper lab show that the macrophage-like hemocytes (which comprise the cellular immune system in flies) go to the intestines ofDrosophila following damage. The hemocytes secrete the growth factor Dpp (a homologue of BMP, which has many functions, including the control of mobility, differentiation and invasiveness of normal cells), setting off the regenerative process by activating specific receptors in stem cells. In a fascinating twist, stem cells switch their response to Dpp in the middle of the regenerative response by turning on other Dpp-related receptors, which in turn instruct the stem cells to go back to a quiescent or quiet state.  Jasper says it’s a balancing act that both allows for healing and prevents excessive cell proliferation, which could lead to pre-cancerous dysplasia. “The temporal sequence of cell interactions during injury-induced regeneration is only beginning to be understood,” said Jasper. “The proper timing of these interactions may be key in maintaining a healthy gut.”

Jasper says aging makes it harder for the stem cells to switch gears between proliferation and quiescence and that flies suffer from age-related intestinal dysfunctions similar to those experienced by humans.

July 28, 2015 Posted by | Medical and Health Research News | , , , , , , , , , , , , , | Leave a comment

Anxiety increases the risk of gastrointestinal infection and long-term complications | EurekAlert! Science News

Anxiety increases the risk of gastrointestinal infection and long-term complications | EurekAlert! Science News.

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From the 2 July 2015 news release

A team comprised of scientists at VIB, KU Leuven and UZ Leuven has made significant progress in uncovering the connection between psychological factors and the immune system. Their findings are based on an investigation of a massive drinking water contamination incident in Belgium in 2010, and are now published in the leading international medical journal Gut.

In December 2010, the Belgian communities of Schelle and Hemiksem in the province of Antwerp faced an outbreak of gastroenteritis, with more than 18,000 people exposed to contaminated drinking water. During the outbreak, VIB and KU Leuven set up a scientific task force to study the incident’s long-term effects, led by Guy Boeckxstaens (UZ Leuven / KU Leuven) and Adrian Liston (VIB / KU Leuven).

Seizing an unexpected opportunity

Adrian Liston (VIB/KU Leuven): “The water contamination in Schelle and Hemiksem was an ‘accidental experiment’ on a scale rarely possible in medical research. By following the patients from the initial contamination to a year after the outbreak we were able to find out what factors altered the risk of long-term complications.”

Anxiety and depression affect immune system

The scientists found that individual with higher levels of anxiety or depression prior to the water contamination developed gastrointestinal infections of increased severity. The same individuals also had an increased risk of developing the long-term complication of irritable bowel syndrome, with intermittent abdominal cramps, diarrhea or constipation a year after the initial contamination.

Guy Boeckxstaens (UZ Leuven / KU Leuven): “Irritable Bowel Syndrome is a condition of chronic abdominal pain and altered bowel movements. This is a common condition with large socio-economic costs, yet there is so much that still remains to be discovered about the causes. Our investigation found that that anxiety or depression alters the immune response towards a gastrointestinal infection, which can result in more severe symptoms and the development of chronic irritable bowel syndrome.”

Psychological factors key in preventing long-term complications

The study’s results provide valuable new insight into the cause of irritable bowel syndrome, and underscoring the connection between psychological factors and the immune system.

Adrian Liston (VIB/KU Leuven): “These results once again emphasize the importance of mental health care and social support services. We need to understand that health, society and economics are not independent, and ignoring depression and anxiety results in higher long-term medical costs.”

July 17, 2015 Posted by | Consumer Safety, Medical and Health Research News, Psychology | , , , , , , , , , , | Leave a comment

   

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