Why older individuals are more prone to developing periodontitis - an inflammatory disease that leads to loss of tooth-supporting bone - and perhaps other chronic inflammatory diseases is presented in a report published in Nature Immunology. These findings suggest a potential treatment to control the destructive inflammatory response associated with periodontal disease.
Periodontitis is marked by chronic recruitment of neutrophils, a class of immune cells that typically respond to the presence of microbes. Neutrophils release toxic molecules into the affected tissues but can also cause local tissue damage.
George Hajishengallis and colleagues found that in young mice a molecule called Del-1 antagonizes neutrophil recruitment, but that older mice express less Del-1 in gingival tissues. Del-1-deficient mice spontaneously develop severe periodontal bone loss, associated with increased numbers of activated neutrophils responding to oral bacteria. Local gingival injections of Del-1 in older mice could protect mice against periodontal inflammation and bone loss. The authors likewise find an inverse correlation of Del-1 expression in human patients with periodontitis.