1. Introduction of human cord blood-derived multipotent stem cells (CB-SCs)
CB-SCs are a unique type of stem cells identified from human cord blood [1, 2], which are different from other types of stem cells including hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs) (Table 1), endothelial progenitor cells (EPC), and monocyte-derived stem cells . Phenotypic characterization demonstrates that CB-SCs display embryonic cell markers (e.g., transcription factors OCT-4 and Nanog, stage-specific embryonic antigen (SSEA)-3, and SSEA-4) and leukocyte common antigen CD45, but they are negative for blood cell lineage markers (e.g., CD1a, CD3, CD4, CD8, CD11b, CD11c, CD13, CD14, CD19, CD20, CD34, CD41a, CD41b, CD83, CD90, CD105, and CD133). Additionally, CB-SC displayed very low immunogenicity as indicated by expression of a very low level of major histocompatibility complex (MHC) antigens and failure to stimulate the proliferation of allogeneic lymphocytes . They can give rise to three embryonic layer-derived cells in the presence of different inducers . More specifically, CB-SCs tightly adhere to culture dishes with a large rounded morphology and are resistant to common detaching methods (trypsin/EDTA), making it easy to collect suspended lymphocytes and separate with CB-SCs after ex-vivo co-culture . Thus, during the Stem Cell Educator therapy, only the CB-SC-educated autologous lymphocytes are returned to the subjects .
2. Introduction of Stem Cell Educator therapy
We recently developed a novel therapy designated Stem Cell Educator therapy , based on our results in non-obese diabetic (NOD) mice and other pre-clinical evidence that CB-SCs can control autoimmune responses by altering Tregs and human islet b cell-specific T cell clones [1, 8, 9]. Briefly, a 16-gauge IV needle is placed in the median cubital vein to isolate lymphocytes from the patient’s blood by using a Blood Cell Separator. The collected lymphocytes are transferred into the device for exposure to CB-SCs, and other blood components are automatically returned to the patient. The Stem Cell Educator functions as part of a closed-loop system that circulates a patient’s blood through a blood cell separator, briefly co-cultures the patient’s lymphocytes with CB-SCs in vitro, and returns the educated lymphocytes to the patient’s circulation. CB-SCs tightly attached to interior surfaces in the device, and only the CB-SC-educated autologous lymphocytes are returned to the subjects. The Stem Cell Educator therapy requires only two venipunctures with minimal pain, and does not introduce stem cells or reagents into patients in comparison with other stem cell-based therapies (e.g., mesenchymal stem cells [MSCs] and hematopoietic stem cells [HSCs]) . Additionally, CB-SCs display very low immunogenicity, eliminating the need for human leukocyte antigen (HLA) matching prior to treatment. Thus, these advantages of Stem Cell Educator therapy may provide CB-SC-mediated immune modulation therapy while mitigating the safety and ethical concerns associated with other stem cell-based approaches and conventional immune therapies.
3. Safety of Stem Cell Educator therapy
Our published data  and unpublished data demonstrated that Stem Cell Educator therapy was well tolerated in all participants (n = 150) with minimal pain from two venipunctures. Most patients experienced mild discomfort during venipuncture and some soreness of the arm during aphaeresis, but discomfort and soreness resolved quickly following the conclusion of the procedure. There were no participants experienced any significant adverse events during the course of treatment, and no adverse events during one year follow-up studies.
In comparison with the application of MSCs, autologous bone marrow-derived MSC has been limited for clinical applications due to the painful operations and potential infections in the procedure for harvesting bone marrow. To this end, placenta or umbilical cords are easy to access and represent valuable sources for provision of allogeneic MSCs. However, patients usually showed medium or high fever following transplant of allogeneic MSCs through interventional therapy such as intravenous delivery or direct infusion into pancreatic islets via transfemoral cannulation under angiography.
Findings from our clinical trials provide powerful evidence that a single treatment with the Stem Cell Educator provides lasting reversal of autoimmunity that allows regeneration of islet b cells and improvement of metabolic control in individuals with long-standing T1D . In an open-label, phase1/phase 2 study, 15 patients with T1D received one treatment with the Stem Cell Educator. Their median age was 29 years (range, 15 to 41), and median diabetic history was 8 years (range, 1 to 21). Stem Cell Educator therapy can markedly improve C-peptide levels, reduce the median glycated hemoglobin A1C (HbA1C) values, and decrease the median daily dose of insulin in patients with some residual b cell function (n = 6) and patients with no residual pancreatic islet b cell function (n = 6). Treatment also produced an increase in basal and glucose-stimulated C-peptide levels through 40 weeks. However, participants in the Control Group (n = 3) did not exhibit significant change at any follow-up. Notably, a single treatment could improve islet b function that lasts a year . Individuals who received Stem Cell Educator therapy exhibited increased expression of costimulating molecules (specifically, CD28 and ICOS), increases in the number of CD4+CD25+Foxp3+ Tregs, and restoration of Th1/Th2/Th3 cytokine balance. Thus, findings from these trials indicate that CB-SC-mediated reversal of autoimmunity results from modulation of the immune response in multiple immune cell types, thereby meeting the expectation that successful therapies will likely address different arms of the autoimmune response and balance the immune system through the systemic and local modulations.
Immune dysfunction of T1D is complicated not only in localizing in pancreatic islets, but also appearing outside of pancreata. There are different compartments of immune system (eg, T cells, Tregs, B cells, DCs, Mo/Mϕ, iNKT) contributing to the autoimmune responses. Therefore, the comprehensive immune modulations via local and systematic approaches are needed to simultaneously address these multiple dysfunctions in clinics. Stem Cell Educator therapy functions as “an artificial thymus” that circulates a patient’s blood through a blood cell separator, briefly co-cultures the patient’s lymphocytes with CB-SCs in vitro, induces the immune tolerance through the action of autoimmune regulator (Aire), returns the educated lymphocytes to the patient’s circulation, and restores the immune balance and homeostasis. During this procedure, both peripheral and pancreatic infiltrated lymphocytes can be isolated by a blood cell separator and treated by CB-SCs. This treatment leads to the global immune modulations and immune balance as demonstrated by our clinical data and animal studies [1, 7, 8, 12].