Stem cells have revolutionized the field of regenerative medicine bringing hope to diseases that seemed to be incurable in the past. Indeed, their unique ability to self-renew and to differentiate into different cell lineages have made them a method of choice to treat diseases like leukemia with therapies such as bone marrow transplants. A work recently published in Science has found a population of stem cells in deer antlers which exhibits a strong regenerative potential and could be applied to medical purposes.

Every year in early spring, old ossified deer antlers cast and a regeneration cycle starts: Nascent antlers start growing from the permanent stumps known as pedicles; in early summer antlers elongate and calcify with a rate of 2.75 cm / day; and at the end of the summer the antlers lose their velvet skin cover and become fully calcified in late autumn until they cast again the next spring.

In order to study their regenerative properties, the authors of this work analyzed the genetic profile of the cells within the antlers at different time points of the antler regeneration cycle and identified an interesting population in the samples. These cells are permanently present in the antlers and can differentiate into chondroblasts (cartilage cells) and osteoblast (bone cells). Interestingly, when implanted into mouse heads, these cells led to the generation of antler-like structures or "mini antlers" in the head of the mice, indicating their ectopic antler regeneration capacity. In addition, these cells share several genes with cells involved in mouse digital tip regeneration, suggesting a conserved core regeneration mechanism in mammals.

In the same work, the authors isolated a subset of cells within this population at the time point when they showed the higher growing rate and identified the genes providing their capability of self-renewal and differentiation. The cells expressing this “regenerative” set of genes showed chondrogenic and osteogenic (but not adipogenic) activity in in vivo cultures, suggesting a potential clinic utility for bone and cartilage regeneration. Finally, such potential was confirmed by the formation of new areas of cartilage and bone after implantation of cells expressing these genes in condyle defective rabbits and immunodeficient mice models.

The perspectives provided by this study are promising for both biological and medical research because it does not only uncover shared genetic mechanisms of regeneration among mammals: the identified deer cells involved in the antler elongation cycle could have an application in clinical bone and cartilage repair that may be used in the future in regenerative medicine for skeletal injuries.

Original article

Qin T, Zhang G, Zheng Y, et al. A population of stem cells with strong regenerative potential discovered in deer antlers. Science. Feb 24 2023;379(6634):840-847. doi:10.1126/science.add0488