Research progress in seed cells for cartilage tissue engineering.

Cartilage defects affect millions of patients worldwide and their repair via conventional treatment is quite difficult. Excitingly, tissue engineering technology provides a promising strategy for efficient cartilage regeneration. The seed cell, as a biological prerequisite for cartilage regeneration, determines the quality of regenerated cartilage. This article reviews in detail the cellular characteristics, research progress, clinical translation challenges and future research directions of various chondrocytes, chondroprogenitor cells and stem cells. Chondrocytes, especially elastic chondrocytes, could complete subcutaneous cartilage regeneration, whereas stem cells are superior for composite defects, allografts and cartilage defects caused by inflammation. In brief, this article provides a guide for selecting appropriate seed cells for cartilage regeneration.