ALPL and type 2 diabetes mellitus: Metformin, which is a first-line drug used for the treatment of type 2 diabetes, has been shown to successfully extend longevity and lifespan in experimental mice.57 Therefore, the use of metformin as an anti-ageing drug has been recently suggested based on its wide application in clinical practice, well-known pharmacokinetics and acceptable toxicity.45,57 In our study, the metformin treatment exhibited a stronger capacity to rescue the function of Alpl+/- MSCs both in vitro and in vivo than the recovery of the Alpl level.