Current
therapy for
type 1 diabetes mellitus involves a daily regimen of multiple subcutaneous or
intramuscular injections of recombinant human
insulin. To achieve long-term
insulin delivery in vivo, we investigated the applicability of cytomedical
therapy using beta TC6 cells or MIN6 cells, both of which are murine pancreatic beta cell lines that secrete
insulin in a subphysiologically or physiologically regulated manner, respectively. We examined this
therapy in the insulinopenic diabetic mice intraperitoneally injected with beta TC6 cells or MIN6 cells microencapsulated within
alginate-poly(L)lysine-
alginate membranes (APA-beta TC6 cells or APA-MIN6 cells). The diabetic mice treated with APA-beta TC6 cells fell into
hypoglycemia, whereas those injected with APA-MIN6 cells maintained normal
blood glucose concentrations for over 2 months without developing
hypoglycemia. In addition, we also conducted an oral
glucose tolerance test using these mice. The
blood glucose concentrations of normal and of diabetic mice injected with APA-MIN6 cells similarly changed over time, although the blood
insulin concentration increased later in the injected diabetic mice than in the former. These results suggest that cytomedicine utilizing microencapsulated pancreatic beta cell lines with a physiological
glucose sensor may be a beneficial and safe
therapy with which to treat
diabetes mellitus.