The described invention provides a method of functionally reprogramming adult cells to an immature cell type that expresses one or more embryonic biomarkers. The reprogramming is accomplished by contacting the adult cells with a platelet rich fraction comprising platelet-like cells from umbilical cord blood or peripheral blood, and expanding the immature cell type in vitro under culture conditions to generate an insulin-producing cell population that expresses human beta-cell specific transcription factors and is functionally equivalent to human pancreatic beta-cells. Without being limited by theory, platelet-like cells and their released mitochondria display immune tolerance-associated markers that may modulate the function and differentiation of immune cells. The described invention further provides a pharmaceutical composition comprising a cell product containing a therapeutic amount of an insulin-producing cell population derived from functionally reprogrammed adult cells, wherein the insulin-producing cell population expresses human beta-cell specific transcription factors and is functionally equivalent to human pancreatic beta-cells.
