You may have heard of your biological clock, but what about your inflammatory clock of aging (iAge)? As this is a relatively recent idea from scientists, you may not know what it means. It’s a way of measuring the aging of your immune system, your risk of developing age-related inflammation and other illnesses, and how that affects longevity.
The research was published in July 2021 (https://www.nature.com/articles/s43587-021-00082-y). The idea was to find a way to measure the aging of the immune system, particularly how its deterioration leads to increased chronic inflammation, which in turn is associated with conditions ranging from Alzheimer’s to heart disease. This could allow for the identification of which people are most at risk of age-related immune problems that can reduce their lifespan.
To conduct the study, researchers analyzed various biomarkers associated with the immune system, most of which are found in the blood. They also investigated the patterns displayed by the immune system’s inflammatory response. These were used to calculate a score that would represent the participants iAge. The blood samples came from the 1000 Immunomes Project, the world’s biggest long-term study into aging and immunology.
Next, they had to test the effectiveness of their iAge algorithm. They chose a group of people from Bologna, Italy, where lifespans tend to be on the longer side. In this case, the participants were all at least 100 years old. However, while their literal age was far above average, their iAge was around 40 years younger. When they were compared to regular people aged between 50 and 79, it soon became apparent that iAge was a better health indicator than age in years.
Multimorbidity is the accumulation of different inflammatory conditions. Subjects with a higher iAge had higher multimorbidity. iAge also correlated with the amount of white blood cells involved in the immune response. A protein called CXCL9 appeared to be one of the most significant indicators of aging and deterioration in the immune system. As its levels increased (most commonly after the age of 60), it damaged what are known as endothelial cells, which triggered inflammation.
Being able to calculate iAge may mean we can identify which people are most at risk of chronic inflammation and age-related immune system problems. This could then lead to more targeted therapies, such as inhibiting CXCL9 to delay aging. The research has a lot of potential.
