Findings help explain why patients who have had bariatric surgery have a 40-50 per cent lower chance of developing cancer and other obesity complications
Bariatric surgery may reverse the damage obesity causes to key immune cells, Irish researchers have found.
A new study by scientists in Maynooth University made this discovery after examining gamma delta (γδ) T cells, a specialised group of immune cells. In particular, the team focussed on a subset called Vδ2+ T cells.
They found that people living with obesity had fewer Vδ2+ T cells in their blood and that the cells were less active when stimulated. The cells also showed abnormalities in the processes that control nutrient uptake and energy production, both of which are essential to an effective immune response.
The findings indicate that obesity disrupts the cells’ metabolism, limiting the energy available to respond to infection and disease.
However, the research team discovered that, when patients with obesity underwent Roux-en-Y gastric bypass (RYGB) surgery, these immune cell defects were reversed.
These patients showed significant improvements in the metabolic processes that support immune cell function, together with a marked recovery in the cells’ ability to respond.
“The findings provide new insight into the relationship between obesity and immune dysfunction, helping to further explain why people living with obesity may be more vulnerable to serious infections, and a range of other conditions,” said Prof Andrew Hogan, Principle Investigator with the Obesity Immunology Research Group at Maynooth University’s Department of Biology.
“They also highlight that obesity is limiting immune cells metabolism, essentially leaving it without the energy it needs to protect us.”
More than one billion adults worldwide live with obesity, which is linked to a greater risk of severe outcomes from viral and bacterial infections. This was highlighted during the COVID-19 pandemic, when people living with obesity faced a significantly higher risk of serious illness.
This new study was led by Dr Ciara Flynn, working in Maynooth’s Kathleen Lonsdale Institute for Human Health Research. Support was received from Prof Helen Heneghan and Prof Donal O’Shea at St Vincent’s University Hospital and University College Dublin.
“Our study highlights that successful treatment of obesity, with RYGB Surgery, reverses this immune dysfunction caused by obesity,” said Prof Henaghan.
“Essentially RYGB surgery restores the body’s defences against infections and cancer, and helps explain why patients who have had bariatric surgery have a 40-50 per cent lower chance of developing cancer and other obesity complications.”
Prof Paul Moynagh, Director of the Kathleen Lonsdale Institute for Human Health Research at Maynooth University, added: “This study is an excellent example of highly impactful translational research.
“It has been achieved by Profs Hogan and Heneghan bringing their scientific and clinical expertise together to provide new insights into how obesity and its treatment affect the immune system in fighting infections and cancer.”
Read the study: Defective Vδ2+ T cell metabolic and functional responses in obesity are reversed with bariatric surgery – JCI Insight.