The role of HIF-1α in maintaining cartilage homeostasis and during the pathogenesis of osteoarthritis

As a consequence of the avascular nature of cartilage the microenvironment in which chondrocytes must exist is characterized by hostile conditions, most prominently very low levels of oxygen (hypoxia). In recent years, a vast number of papers reporting on the role of hypoxia in cartilage development and disease has been published. It is well established today that the principal mediator of cellular adaptation to hypoxia, the transcription factor hypoxia inducible factor (HIF)-1, is of pivotal importance for survival and growth arrest of chondrocytes during cartilage development as well as energy generation and matrix synthesis of chondrocytes in healthy as well as osteoarthritic cartilage. With this commentary we aim to briefly discuss the recently published literature in this field.