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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Blood Glucose, Bone Marrow Transplantation, Diabetes Mellitus, Experimental, Diabetes Mellitus, Type 1, Flow Cytometry, Follow-Up Studies, Insulin, Male, Mice, Mice, Inbred C57BL, Pancreas, T-Lymphocytes, Regulatory, Transplantation, Autologous, Transplantation, Isogeneic.
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Is time point important for effects of syngeneic bone marrow transplantation for type 1 diabetes in mice? Context: Autologous hematopoietic stem cell transplantation (HSCT) has recently become a novel therapy for patients with new-onset type 1 diabetes (T1D). However, the optimal time points for HSCT are still unknown. By using multiple low-dose streptozotocin (STZ)-induced T1D mice models, we performed syngeneic bone marrow transplantation (syn-BMT) in diabetic mice at various time points new-onset day 3 (n = 12); new-onset day 10 (n = 13); later-onset day 20 (n = 12); and day 40 (n = 7), respectively. At 120 days after syn-BMT, we examined pancreata histology, serum insulin, and CD4(+)CD25(+)FoxP3(+) T regulatory lymphocytes (Tregs). Our previous results showed that syn-BMT can overcome diabetes when performed on day 10, but not at day 40. Our new data showed BMT only attenuated diabetes when done on day 3 or day 20. Moreover, the percentage of Tregs in the spleen correlated with the attenuation of hyperglycemia.
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These results indicated that syn-BMT should be performed, when diabetes is neither too new-onset nor too late-stage. Tregs represent one mechanism for syn-BMT-induced restoration of immune tolerance in STZ-diabetic mice. Final Decision: yes