Christine Mummery and Eric Anthony discuss some key changes to the ISSCR Guidelines for Stem Cell Research and Clinical Translation, which concern, among other experimental procedures, the culturing of human embryos, genome editing and mitochondrial replacement techniques.

Satellite cells are skeletal muscle stem cells that are largely quiescent. They are activated upon muscle damage and differentiate into muscle cells or return to quiescence. These processes are controlled by cell-intrinsic mechanisms and by signals from the niche, and are deregulated in ageing, leading to impaired muscle regeneration.

Xie et al. show that the hair shaft regulates the size of the hair follicle stem cell niche and consequently its maintenance.