Killifish exhibit distinct structural changes and fibrosis during cardiac aging
Long-lived African turquoise killifish show ventricular enlargement, fibrosis, and reduced myocardial density with age rather than typical cardiomyocyte hypertrophy.
In the African turquoise killifish (Nothobranchius furzeri), researchers characterized age-related cardiac remodeling using the long-lived MZCS strain. The authors compared hearts from young fish aged 1.5 months with old fish aged 7 to 10 months of both sexes using histology, quantitative image analysis, and gene expression assays. Old killifish developed ventricular enlargement, epicardial thickening, valvular abnormalities, and prominent interstitial myocardial fibrosis. Unlike findings in mammals and zebrafish, aged killifish did not display cardiomyocyte hypertrophy. Instead, their hearts exhibited reduced myocardial density and marked thinning of peripheral trabeculae. Glycogen-like material accumulation tended to be more pronounced in young fish, while most glucose metabolism genes showed no marked age-related shifts. Furthermore, senescence-associated beta-galactosidase activity was robustly present from early life onward, indicating it is an intrinsic cardiac feature rather than a simple chronological aging marker in this model.
Why it matters
These findings highlight both conserved traits like fibrosis and species-specific mechanisms in vertebrate heart aging. The work establishes the MZCS killifish strain as a viable model for dissecting structural modes of cardiac decline within a short timeframe.
Caveats
The study was conducted in a fish model whose cardiac aging features, such as the lack of cardiomyocyte hypertrophy, diverge from mammalian biology. The analysis was also limited to histological, imaging, and selective marker comparisons between two specific age groups.
The paper
Structural and metabolic signatures of cardiac aging in African turquoise killifish (Nothobranchius furzeri)
Hishida R, Otsuka T, Toyokuni S et al.
Histology and Histopathology · 28 Sep 2026