# Jackson Laboratory maps hotspots of uneven cardiac aging in mouse hearts

- Published: 2026-11-07 05:18 UTC
- Section: Life & Health › Biology & biochemistry
- Tags: cardiac aging, Jackson Laboratory, mouse heart, aortic valve, inflammaging, fibroblasts, macrophages
- URL: https://realtech.media/news/rt-c2d045009ae50cb9dc98c842_jackson_laboratory_maps/

**Researchers analyzed whole mouse hearts to show that age-related inflammation and fibrosis concentrate primarily in the aortic valves and aortic root.**

![Jackson Laboratory maps hotspots of uneven cardiac aging in mouse hearts](https://realtech.media/media/2026/11/cb2eef66e5e56ace.jpg)
*Lena Gulenko, Wikimedia Commons, CC BY 4.0*

Scientists from The Jackson Laboratory (JAX) published a spatial genomic study showing that cardiac aging does not occur uniformly throughout the heart. According to an announcement released via EurekAlert, the researchers analyzed thousands of cells from young and aged mouse hearts, identifying specific anatomical hotspots where signals of chronic inflammation and tissue remodeling accumulate [1]. Rather than being evenly distributed across the myocardium, cellular hallmarks of aging were clustered in the heart valves and the aortic root.

Previous investigations focused primarily on the left ventricle and contractile muscle cells. Using single-cell and spatial genomics technologies, the JAX team examined whole organ architecture to track structural and immune components [1]. The data revealed that structural fibroblasts and immune macrophages accumulate in the aortic root and valves, driving localized changes. Macrophages exhibited increased expression of genes related to inflammation and tissue remodeling, while fibroblasts shifted toward profibrotic pathways, elevating molecular markers such as Ccl8 and Cdkn1a (p21).

## Spatial hubs and molecular markers

The researchers noted that certain molecular markers commonly associated with cellular senescence were present in the aortic valves of young, six-month-old mice. This indicates that these markers alone do not necessarily denote senescent arrest, requiring a reevaluation of standard identification methods [1]. The study identified that the persistent signaling between immune cells and structural fibroblasts in these vascular regions serves as a focal driver of age-related cardiac changes.

## Sex-dependent pathways

The analysis also identified sex-specific molecular differences in aging fibroblasts. In male mice, aging fibroblasts demonstrated activation of pathways linked to fibrosis, whereas in female mice, they were associated with pathways related to cardiac development and protein synthesis [1]. Comparative analyses with published human datasets confirmed that several stress-response programs observed in mice are conserved in human cardiac tissue.

## Sources

1. [EurekAlert](https://www.eurekalert.org/news-releases/1150882)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-c2d045009ae50cb9dc98c842_jackson_laboratory_maps/