Body Fluids as a Stem Cell Reservoir: Myth, Mystery, or Medical Revolution?

Abstract

For decades, the prevailing paradigm of stem cell biology emphasized specialized tissue niches as the principal reservoirs of adult stem and progenitor cells, although clinically important hematopoietic stem cell populations from peripheral blood and umbilical cord blood have long been recognized and successfully utilized. Accumulating evidence now demonstrates that additional stem and progenitor cell populations can be isolated from a broad spectrum of human body fluids, such as urine, menstrual blood, peripheral blood, umbilical cord blood, amniotic fluid, synovial fluid, breast milk, and cerebrospinal fluid. The central question in regenerative medicine has consequently shifted from verifying the existence of these cells to deciphering their biological origins, physiological functions, and ultimate translational potential. Body fluid-derived stem cells (BFSCs) represent an extraordinarily accessible, non-invasively obtained source of regenerative biological material, yet significant questions remain regarding their cellular turnover dynamics, heterogeneity, and therapeutic scalability. Moreover, major challenges remain regarding standardization, lineage
tracing, manufacturing reproducibility, and regulatory approval for clinical translation.This manuscript systematically reviews the origin, biological landscape, translational advantages, current preclinical applications, and future trajectories of BFSCs, framing them as a candidate paradigm shift in regenerative and precision medicine.