Immune Protein May Link Chronic Inflammation and Frailty in Older Adults

A study in the Journals of Gerontology, Series A details a possible link between chronic inflammation and frailty and the immune protein interleukin-6 (IL-6), reports Medical Xpress . Johns Hopkins Medicine researchers genetically engineered a mouse model that develops chronic inflammation but does not have IL-6. The model can be used to ascertain if the absence of IL-6 during uncontrollable chronic inflammation can shield against age-related physical and functional deterioration. The team learned that frail mice missing IL-6 built up circulating fat compounds critical in maintaining healthy mitochondria function, which decline with age in humans. The frail, IL-6-lacking mice also produced more heart energy compared to those mice that generated the protein, and both these findings indicate that improvements in mitochondrial function occurred in frail mice when IL-6 was lacking. In tests involving mice running on a treadmill, "frail mice without IL-6 had short-term improvements in running and fewer falls off the treadmill, but this improvement disappeared after three days," noted Johns Hopkins Medicine Professor Peter Abadir. "Surprisingly . . . we observed dramatically higher mortality in these mice in the presence of chronic inflammation — as high as a fourfold increase compared with nonmodified mice and with mice that developed chronic inflammation but could still produce IL-6." These observations imply a delicate balance between aging and chronic inflammation, and IL-6 may be needed to maintain long-term exercise ability and prevent premature death.