The quest for tissue stem cells in the pancreas and other organs, and their application in beta-cell replacement

Adult stem cell research has drawn a lot of attention by
many researchers, due to its medical hope of cell replacement
or regenerative therapy for diabetes patients. Despite
the many research efforts to date, there is no consensus on
the existence of stem cells in adult pancreas. Genetic lineage
tracing experiments have put into serious doubt whether beta-
cell neogenesis from stem/progenitor cells takes place
postnatally. Different in vitro experiments have suggested
centroacinar, ductal, acinar, stellate, or yet unidentified clonigenic
cells as candidate beta-cell progenitors. As in the rest of
the adult stem cell field, sound and promising observations
have been made. However, these observations still need to
be replicated. As an alternative to committed stem/progenitor
cells in the pancreas, transdifferentiation or lineage reprogramming
of exocrine acinar and endocrine beta-cells may
be used to generate new beta-cells. At present, it is unclear
which approach is most medically promising. This article
highlights the progress being made in knowledge about tissue
stem cells, their existence and availability for therapy in
diabetes. Particular attention is given to the assessment of
methods to verify the existence of tissue stem cells.