Scientists in Vienna have built what they call the Human Aging Endothelial Cell Atlas, a map of how the cells lining the inside of human blood vessels change as people get older1. The team pooled gene activity data on more than 375,000 cells from 290 samples across 12 human tissues, drawn from 34 studies that other groups had already published1. Coverage of the work described it as the first atlas of its kind for human endothelial cells2. The results appear in the peer-reviewed journal Nature Aging1.
What happened
Blood vessels are not just tubes. Their inner walls are covered by a thin layer of specialized cells called endothelial cells, which regulate blood flow, control what passes into nearby tissue and help coordinate responses to injury1. They also take on jobs specific to each organ, such as forming a protective barrier in the brain or supporting filtration in the kidneys2.
As people age, this system can stop working well, which raises the risk of heart and blood vessel disease1. Yet according to the research institute, these cells are often overlooked in aging research, and what happens inside them over time remains poorly understood1.
The study was led by Laura de Rooij, a principal investigator at CeMM, the Research Center for Molecular Medicine of the Austrian Academy of Sciences, with PhD student Sarah Dobner as first author12. Instead of studying whole vessels, the team used single-cell analysis, a method that reads which genes are switched on in each individual cell1. They focused on tissue classified as healthy or free of diagnosed disease, to separate changes linked to aging from changes driven mainly by illness1.
What the atlas found
The main message is that vessel lining cells do not all age the same way. Changes differed depending on the tissue and the part of the blood vessel system2. Dobner said in the institute’s release:
One of the most striking findings was that endothelial aging does not look the same across the vascular system. By bringing together data from different tissues, we could identify patterns that might have been missed by studying individual organs or endothelial cell types in isolation
Specific patterns the team reported:
- Vein linings. Cells lining veins can sprout new blood vessels, part of how the vessel network renews itself. In older people, these cells showed lower activity of several genes involved in forming vessels1.
- Inflammation and “worn-out” cells. Across several tissues, older samples showed higher activity of genes linked to inflammation and to cellular senescence, a state in which cells stop dividing and can affect the cells around them1.
- Sensing force. These cells constantly feel the push of flowing blood and the material around them. The atlas showed age-related changes in genes involved in turning those physical signals into biological responses1.
The team also ran experiments on human skin. A protein called YAP, which helps cells respond to physical forces, was found more often inside the nucleus (the cell’s control center) of vessel lining cells from older donors1.
Finally, the researchers found a group of genes associated with p21, a protein that can slow or stop cell division1. Comparisons with lab-grown endothelial cells and with mice bred to age faster supported a link to cellular senescence1.
What it does not show yet
The study has clear limits, and the researchers and coverage spell several of them out.
- A snapshot, not a timeline. The study compared different people of different ages. It did not follow the same people as they aged2.
- Missing background. Information on donors’ lifestyles and medical histories was incomplete, which limits the conclusions1.
- Gene activity is not function. The lower activity of vessel-forming genes in vein linings could help explain why vessels may renew themselves less well with age, but the study did not directly measure repair ability1.
- Good change or bad change? The team has not determined whether the extra YAP in older cells helps them cope with aging or contributes to declining vessel function2.
- Hard to tell cells apart. The p21-linked genes also take part in stress responses and vessel growth, so they cannot reliably separate permanently senescent cells from cells reacting to other age-related challenges1.
The institute’s release says some of the changes may drive declining function while others could be the body trying to protect itself, and that telling them apart is needed before scientists can decide which processes to target1. No treatment was tested.
Who is behind it
The work comes from Laura de Rooij’s group at CeMM in Vienna, described in coverage as leading an international team2. The main account of the findings comes from the institute’s own press release1. The sources read for this article do not describe the study’s funding or any company ties.
The lab has posted its analysis code publicly. The repository describes scripts that group the cell data by donor and age bracket and then compare gene activity in older versus younger samples, tissue by tissue3. It also lists the underlying cell datasets on Zenodo, a public data archive, marked as released upon publication, and a separate analysis of cells with and without activity of a gene called CDKN1A3. The study itself describes an interactive portal for other researchers to explore the data1.
How it fits the field
Single-cell atlases have become a common way to study aging and organ biology. Earlier work pooled data for blood vessel cells in a single organ: a 2021 study in the journal Circulation reanalyzed 6 datasets to describe more than 15,000 vessel lining cells from 73 people’s lungs, though that work mapped cell types rather than aging4. Other projects have built aging atlases of single human organs, such as a skeletal muscle atlas comparing young adults and older people5.
The idea that vessel lining cells change with age is also not new. A 2016 lab study from Vienna reported that aging endothelial cells grown in a dish were larger, had shorter telomeres (the protective caps on chromosomes), made more inflammatory signals and moved shorter distances6. In that study, adding a protein called Ang2 back to aged cells restored their ability to move6. That was a lab dish study, not a study in people.
What the new atlas adds is breadth: one resource that lines up the same cell type across 12 human tissues, so researchers can see where aging patterns match and where they differ1.
What to watch next
- Whether other labs use the public portal and code to test the atlas’s patterns in new samples13.
- Studies that follow the same people over time, which this design could not do2.
- Experiments that directly measure whether vein lining cells in older people repair and sprout vessels less well, and whether YAP’s shift into the nucleus helps or harms1.
For now, the atlas is a map of where to look, not evidence that any change in these cells causes disease or that anything can reverse it.
