Adipose tissue as a living drug: Stromal vascular fraction and adipose tissue-derived stem cells in regenerative medicine

Adipose tissue has emerged as a rich and clinically relevant source of regenerative cells. It offers a minimally invasive, abundant, and autologous reservoir for therapeutic applications. Among its cellular components, the stromal vascular fraction (SVF) and adipose-derived stem cells (ASCs) have gained considerable attention due to their potent regenerative and immunomodulatory capacities. SVF is a heterogeneous mixture of cells, whereas ASCs constitute a more homogeneous mesenchymal stem cell-like population obtained through <i>in vitro</i> expansion. Together, these cell populations (SVF and ASCs) are described as "living drugs", as they are viable and act as dynamic biological agents within the body. Unlike conventional medicines, living drugs exert therapeutic effects not only through direct differentiation but also <i>via</i> the secretion of bioactive molecules, including cytokines, growth factors, and extracellular vesicles. These secreted factors can modulate the surrounding microenvironment, enhance tissue repair, and regulate immune responses. Such paracrine mechanisms often play a more significant role than direct cell replacement, making living drugs versatile tools for regenerative medicine. This review provides a comprehensive overview of SVF and ASCs as living drugs. It discusses their cellular composition, mechanisms of action, methods of isolation, and the regenerative biomolecules they secrete. Furthermore, it explores current and emerging clinical applications, challenges, and future innovations.