Study links aging cells to falling phosphatidylcholine levels

Researchers at the Leibniz Institute on Aging—Fritz Lipmann Institute in Germany say they have identified a lipid change that can help drive age-related mitochondrial decline. The finding matters because mitochondria supply cells with energy, and their weakening is tied to reduced cellular flexibility during aging.

In a study published in Nature Communications, the team linked aging mitochondria to lower production of phosphatidylcholine, a common lipid in cell membranes. According to FLI, boosting phosphatidylcholine or its precursor, choline, improved mitochondrial structure and energy function in aging laboratory worms.

A lipid tied to mitochondrial networks

Mitochondria do more than generate energy. FLI said they also help cells respond to changing demands, share metabolic materials and maintain communication inside cells.

The researchers focused on mitochondrial fusion, the process by which mitochondria connect into networks. Those networks help distribute energy molecules, DNA, metabolic products and signaling compounds, according to the institute.

Phosphatidylcholine helps membranes stay flexible enough to reorganize, FLI said. The study found that phosphatidylcholine production declines with age, and that loss was associated with fragmented, less effective mitochondrial networks.

When researchers disrupted genes involved in phosphatidylcholine production in young Caenorhabditis elegans worms, their mitochondria quickly took on features usually seen in older animals, according to FLI. Feeding worms phosphatidylcholine or choline restored a more youthful mitochondrial structure within two days.

“We were surprised ourselves by how strongly this molecule influences the structure, connectivity, and function of mitochondria,” said Tetiana Poliezhaieva, the study’s first author.

Worm experiments and human data

The research combined experiments in C. elegans, studies in human cell cultures and analysis of clinical datasets, according to FLI. The team examined proteins, lipids, genetic variation, gene activity and metabolic function across stages of human aging.

FLI said the combined data tied molecular changes seen in laboratory models to patterns found in people. The worm studies were used to test cause and effect across the whole organism.

The authors reported that mitochondrial aging appears to reflect more than accumulated genetic damage. Their findings point to changes in lipid production and membrane behavior as part of the process.

Maria Ermolaeva, who led the study, compared the mitochondrial network to a power grid that becomes damaged with age. “Although energy production continues, it becomes less efficient and sustainable, and energy can no longer be distributed flexibly,” she said.

Possible stages of aging

The study also suggests aging may involve distinct phases, according to FLI. The researchers found early changes in stress resistance and protein homeostasis, followed by metabolic changes, with epigenetic alterations appearing later.

FLI said the team also observed sex-specific differences in lipid metabolism. Human metabolomic data showed the largest relative decline in phosphatidylcholine levels among women around menopause, the institute said.

Ermolaeva said that timing was notable because it overlaps with a period when many women report lower energy and persistent fatigue. The study did not show that phosphatidylcholine decline causes those symptoms in humans.

No human treatment yet

The clearest intervention evidence came from worms. According to FLI, raising phosphatidylcholine levels in older C. elegans made mitochondrial networks more stable and improved energy production, including when given in middle or advanced age.

“Our work shows that both mitochondrial aging and broader systemic aging are, at least in part, modifiable. If we understand the underlying processes, we may be able to take targeted countermeasures,” Ermolaeva said.

Further research is needed to determine whether the findings can support therapies or nutrition-based interventions in people, FLI said. For now, the study identifies phosphatidylcholine synthesis as a malleable trigger of mitochondrial aging in the models tested.

This story draws on original reporting from ScienceDaily.