Current understanding and new promises of umbilical cord blood in emerging clinical applications.

Umbilical cord blood (UCB) has become an important resource for regenerative medicine owing to its unique cellular composition, immune immaturity, and abundance of bioactive factors. Although UCB was initially applied in hematopoietic stem cell transplantation, accumulating evidence indicates that its diverse cellular and paracrine components possess broad regenerative potential. Beyond conventional hematopoietic stem cell transplantation, substantial progress has expanded the therapeutic scope of UCB to immune cell-based therapies, the treatment of genetic and metabolic disorders, and tissue repair. In this review, we focus on the biological characteristics of the key cellular and noncellular components of UCB and analyze how these properties support tissue repair, immunomodulation, and regeneration across multiple organ systems. We further summarize recent technological advances, including cell engineering, gene modification, and manufacturing technologies, that have enhanced the scalability and therapeutic potential of UCB-derived products. In addition, we highlight current challenges that limit their widespread clinical application. This review aims to provide a framework for optimizing UCB-based therapies and accelerating their clinical translation. Optimizing UCB collection, processing, and application strategies may further unlock its therapeutic potential, thereby improving clinical efficacy and expanding its applicability to a broader range of diseases.