Researchers identify elusive human skeletal stem cells.
It is known that the human skeleton is an amalgam of diverse tissue types including bone, cartilage and fat cells. Each tissue type in the skeleton is generated and maintained by the precise regulation of stem cells which possess the ability to replenish themselves via specific cell-lineages, with researchers looking for the elusive stem cell-type for bone and cartilage. Now, a study from researchers led by Stanford University isolates human skeletal stem cells, which become bone or cartilage cells from fetal and adult bones. The team state that they were also able to derive the skeletal stem cells from human induced pluripotent stem cells, opening up a realm of therapeutic possibilities. The opensource study is published in the journal Cell.
Previous studies show that skeletal dysfunction can lead to a broad spectrum of health conditions ranging from age-related diseases such as osteoporosis and osteoarthritis to non-healing skeletal injury, blood disorders, and even cancer. However, despite its significant impact on health and disease, treatment options aimed at improving skeletal function are currently limited. One major hurdle is that stem cell regulation in the human skeletal system remains largely unexplored, with only rodent studies identifying skeletal stem cells. The current study identifies and characterizes human skeletal stem cells and downstream bone and cartilage progeny in a variety of tissues.
The current study analyzes cells from human tissue located in bone growth plate zones, which produce cells for bone growth. Results, using single cell analysis of RNA sequences, identifies potential human skeletal stem cells with gene expression similar to the previously characterized mouse skeletal stem cells. Data findings show these self-renewing and multipotent cells were present in both fetal and adult human bone marrow tissues and could be derived from induced pluripotent stem cells.
Results show that these cells can be isolated from various human tissue sources and quantify their response to fracture. Data findings show that comparison of human skeletal stem cells with mouse skeletal stem cells provides insights into convergent and divergent skeletal evolution. The lab explain that by comparing the molecular and functional differences in specific types of stem cells between different species of vertebrates, it may be possible to uncover convergent and divergent mechanisms that underlie tissue growth and regeneration and apply this understanding towards enhancing health and rejuvenation in humans.
The team surmise they have successfully isolated human skeletal stem cells capable of self-renewal and multilineage differentiation into bone, cartilage, and stroma. For the future, the researchers state they envision a multitude of applications for their technique, including a time when readily available fat cells from liposuction could be turned into stem cells which could then be injected into joints to make new cartilage, or stimulated to form new bone in the repair fractures.
Source: National Institutes of Health