Scientists from the School of Dental Medicine at the University of Boston Medical Center are looking at a possible link between obesity and immune system function. Previous research has found that obese people are more likely to suffer from periodontal disease than lean people. This new study looked at why.
Researchers worked with laboratory mice — some who were obese and some who were lean and healthy. The mice were infected with a bacterium that causes periodontal disease (porphyromonas gingivalis). The obese mice were more susceptible to gum disease and had a blunted immune system reaction to the infection.
Ten days after infection, the obese mice had a forty percent higher alveolar bone loss than lean mice. The alveolar bone is the ridge that contains tooth sockets on the upper and lower jaw.
So why are overweight mice having trouble fighting off bacterial infection?
Cytokines are proteins (also known as peptides) that signal immune system cells to come and fight infection. Obese mice in the study had irregular cytokine production — so the proteins in obese mice weren’t calling for help the way the proteins in lean mice do.
The immune system cells — like T-cells and macrophages — weren’t quite right in obese mice, either. The macrophages (a kind of white blood cell) were at much lower levels in obese mice than in healthy mice. Inflammation-related genes were also different between the obese mice and the lean mice.
All this may not mean a whole lot to the average person, but it gives a few clues to experts on the relationship between obesity and the immune system. The researchers from the University of Boston suspect that the body’s signal for help (at the site of an infection) is important. Further tests are planned to look at just how extra pounds influence the body’s response to infection.
While we’re waiting for definite answers, it does seem like another benefit to losing some extra weight will be a stronger immune system!