Mapping Lipid Changes with Age in Mice Points to the Gut Microbiome

Researchers here note some interesting findings when mapping age-related changes in the levels of lipid metabolites present in tissues in mice. This is a starting point on the road to finding novel aspects of aging that might be addressed. The researchers focus down on changes related to lipids produced in the gut microbiome. It is presently known that the gut microbiome is influential in health and pace of aging, and that the relative population sizes of microbial species undergo harmful changes with age. While some inroads have been made, a complete map of specific problematic changes has yet to be produced; here researchers have found another point of entry to that mapping process.

Lipids, often in the form of fats or oils, are essential molecules for storing energy in our bodies, among other things. In addition, lipids act as signaling molecules and as components of cell membranes. Metabolism - the breakdown of biomolecules such as lipids and sugars into their component parts - slows down as we age, which helps explain why it's easier to gain weight, and more difficult to lose it, as we get older. Although this has been known for over 50 years, how changes in lipid metabolism in particular affects lifespan and health remain unclear. Before this question can be fully answered, we need to know what the actual changes are, in great detail. Only then can scientists begin looking for links between aging lipid metabolism and human health. Toward this end, researchers used mice to develop an atlas of age-related changes in lipid metabolites.

By using a cutting-edge technique to take multiple snapshots of the mouse lipidome - all lipid metabolites present in a biological sample - the researchers found that bis (monoacylglycero) phosphate (BMP) type lipids increased with age in the kidneys, liver, lungs, muscles, spleen, and small intestine of the mice. These lipids play key roles in cholesterol transport and the breakdown of biomolecules within cellular recycling centers called lysosomes. Age-related lysosomal damage might result in cells making more BMPs, which could lead to further metabolic changes, such as increasing cholesterol derivatives in the kidney.

The researchers also investigated the impact of gut bacteria on the lipidome, discovering that while gut bacteria produced many structurally unique lipids, only sulfonolipids increased with age in the liver, kidney, and spleen. In fact, no other group of lipid metabolites from gut bacteria were even detected in these peripheral tissues. "As this kind of lipid is known to be involved in regulating immune responses, the next phase of our research will involve testing the gut bacteria-derived sulfonolipids to determine their structure and physiological functions."