Objectives: The origin of adult stem cells remains an open question. If they derive from embryos, it is difficult to determine the mechanism which interrupts their differentiation during tissue formation. In the 1960s, the Bonghan microcell was suggested as one possible, yet to be described, route of stem cell production, such that they have the potential to proliferate to produce normal cells.
Materials and methods: In this study, Bonghan microcells were isolated from Bonghan tissues on rat organ surfaces, and their detailed morphology examined by electron and atomic force microscopy.
Results: The ultrastructure observed distinguished them from apoptotic bodies and other microorganisms, and their unique, possible proliferation feature, as protruding threads, was imaged by atomic force microscopy.
Conclusions: The unique threadlike structure of the Bonghan microcell is consistent with Prof. Kim's observation in the first step of making a cell. Understanding of the functions of this threadlike structure may give a clue to understand the origin or the differentiation cue of adult stem cells.