Aging Cell: Calorie restriction slows aging of brain cells

Long-term reduction of calorie intake by about one third may slow the aging of cells that maintain white matter in the brain. This conclusion was reached by scientists from Boston University and the US National Institute on Aging. The study was published in the journal Aging Cell.

White matter consists of nerve fibers covered with myelin. Oligodendrocytes are responsible for producing myelin, while microglia are responsible for immune surveillance in the brain. With age, these cells become less effective, leading to myelin sheath degradation, reduced signal transmission, and cognitive decline.

To determine whether diet can influence this process, the aforesaid scientists studied the brains of adult rhesus macaques that had participated in a 30 percent calorie restriction experiment for over two decades. Their data were compared with age-matched animals fed a normal diet.

The tissue of the primary region of one myelin-rich area of the brain was analyzed using single-nucleus RNA sequencing. This enabled tracking active genes in thousands of individual cells.

It was found that the total number of glial cells in both groups was virtually identical, but their “internal” function differed significantly. In calorie-restricted animals, oligodendrocytes maintained a healthier metabolic profile: genes responsible for fatty acid synthesis and energy production needed to maintain myelin were more active. In contrast, stress and inflammation genes were elevated in control animals.

Researchers paid special attention to a group of so-called “synaptic” oligodendrocytes located near nerve axons. In calorie-restricted macaques, these cells more frequently activated the NLGN1 gene, which is associated with intercellular connectivity. Microscopy showed that these cells were indeed closer to the fibers, which may improve signal transmission.

Scientists also observed differences in T-lymphocytes, which are normally foreign to neural tissue, with age. In the control group, their numbers increased faster, which may indicate deterioration of the brain’s protective barriers. This process occurred more slowly in calorie-restricted animals.

According to the authors, the aforesaid study shows that calorie restriction can reprogram glial cell metabolism and thus maintain white matter health. Such interventions could be one tool for combating age-related brain disorders, alongside physical activity and overall metabolic strategies.