Bariatric surgery restores metabolic and immune responses in obesity
Baku, October 22, AZERTAC
People living with obesity had fewer circulating Vδ2+ T cells and showed weaker responses when those immune cells were stimulated, according to an experimental study led by Maynooth University researchers, as reported by Bioengineer.org.
The peer-reviewed research found that Roux-en-Y gastric bypass surgery was followed by significant improvements in the cells’ metabolic activity and functional responses, reversing many of the defects observed in obesity. The study, published in JCI Insight, examined a specialized subset of gamma delta T cells involved in rapid immune defense and the recognition and destruction of certain cancer cells.
Researchers reported that obesity was associated with reduced numbers of Vδ2+ T cells in the blood. When stimulated in the laboratory, the cells from people with obesity were less active than those from comparison participants. The affected cells also displayed abnormalities in nutrient uptake and energy production, two processes that support the cellular demands of an effective immune response. These observations provide a potential cellular explanation for impaired immune responses in obesity, although the experiment does not establish that the metabolic changes directly caused the reduced cellular function.
The work focused on cells rather than demonstrating clinical protection against infection or cancer. Vδ2+ T cells are described in the research as part of the body’s early defense against infection and can identify and destroy certain cancer cells. The investigators therefore assessed both how these cells functioned after stimulation and how they obtained fuel and generated energy. The findings indicated that obesity disrupted important features of immune-cell metabolism, potentially limiting the resources available for a rapid response. The study used an experimental design, and its results concern biological responses measured in cells; they should not be interpreted by themselves as proof that surgery prevents disease in patients.
After Roux-en-Y gastric bypass, or RYGB, participants showed significant improvement in the metabolic processes that support immune-cell function. The surgery was also followed by a marked recovery in the cells’ capacity to respond to stimulation. The researchers concluded that the metabolic and functional defects detected in obesity were reversed following the procedure. Because the supplied report does not describe the number of participants, duration of follow-up, effect estimates, or the design of any comparison involving surgery, it does not establish the size or durability of the treatment effect or support broad clinical recommendations.
The research was conducted by Dr Ciara Flynn of Maynooth University’s Department of Biology, working in the research group led by Prof Andrew Hogan at the Kathleen Lonsdale Institute for Human Health Research. It was carried out in collaboration with Prof Helen Heneghan and Prof Donal O’Shea at St Vincent’s University Hospital and University College Dublin, and was funded by the Health Research Board. Hogan said the results offer new insight into the relationship between obesity and immune dysfunction, while Prof Paul Moynagh described the project as an example of translational research connecting scientific and clinical expertise. Heneghan said the findings show that successful obesity treatment with RYGB was associated with reversal of the measured immune dysfunction.
Obesity is widely associated with increased risks of severe infection and other health complications, but identifying a biological mechanism is different from proving a clinical outcome. The Maynooth study suggests that altered energy metabolism in Vδ2+ T cells may be one factor connecting obesity with diminished immune readiness. It also shows that these measured cellular abnormalities can improve after bariatric surgery. Whether that recovery translates into fewer infections, better cancer outcomes, or durable immune benefits remains a separate question requiring appropriately designed clinical research.
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