The enormous variety of degenerative aging, the many forms of declining function and organ failure, derives from a simpler array of underlying cell and tissue damage. One might look at the SENS research proposals for an overview of that damage. Given this, it isn't surprising to see that many age-related conditions share metabolic signatures. One might suppose these signatures to be reactions to specific forms of damage or consequences of specific forms of damage.
Many elderly people suffer simultaneously from several, frequently very different diseases, a condition also known as multimorbidity. In a recent study, researchers have now identified a number of metabolic processes that are associated not only with one, but simultaneously with up to 14 diseases.
The scientists first examined the concentration of hundreds of different molecules in the blood samples of a total of 11,000 study participants. They then examined how the concentration of individual metabolites was related to the onset of a total of 27 serious diseases in the participants. The metabolites included not only known metabolic products such as sugars, fats, and vitamins, but also substances whose concentration depends on genetic or environmental factors. For example, the scientists were able to detect the degradation products of medications, coffee consumption or the presence of gut bacteria using a process known as molecular profiling.
The blood samples had already been taken from the participants more than 20 years ago and been stored at minus 196 degrees Celsius since then. At that time, the people were mostly healthy. The diseases they developed afterwards were systematically recorded in detail for more than 20 years through electronic hospital data.
For example, the team found that the concentration of many metabolites in the blood that were associated with disease onset were explained by impaired liver and kidney function, obesity, or chronic inflammation. But they also discovered that certain lifestyle factors or a reduced diversity of intestinal bacteria, also known as the gut microbiome, influence blood levels and can thus provide clues to the development of diseases over time. It turned out that half of all detected molecules were associated with an increased or decreased risk of at least one disease - the majority with multiple, sometimes very different, diseases, pointing to metabolic pathways that increase the risk of multimorbidity.