Mark J. Holterman

Reversal of type 1 diabetes via islet β cell regeneration following immune modulation by cord blood-derived multipotent stem cells.

BackgroundInability to control autoimmunity is the primary barrier to developing a cure for type 1 diabetes (T1D). Evidence that human cord blood-derived multipotent stem cells (CB-SCs) can control autoimmune responses by altering regulatory T cells (Tregs) and human islet β cell-specific T cell clones offers promise for a new approach to overcome the autoimmunity underlying T1D.MethodsWe developed a procedure for Stem Cell Educator therapy in which a patients blood is circulated through a closed-loop system that separates lymphocytes from the whole blood and briefly co-cultures them with adherent CB-SCs before returning them to the patients circulation. In an open-label, phase1/phase 2 study, patients (n = 15) with T1D received one treatment with the Stem Cell Educator. Median age was 29 years (range: 15 to 41), and median diabetic history was 8 years (range: 1 to 21).ResultsStem Cell Educator therapy was well tolerated in all participants with minimal pain from two venipunctures and no adverse events. 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 β cell function (n = 6) and patients with no residual pancreatic islet β 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. Individuals who received Stem Cell Educator therapy exhibited increased expression of co-stimulating molecules (specifically, CD28 and ICOS), increases in the number of CD4+CD25+Foxp3+ Tregs, and restoration of Th1/Th2/Th3 cytokine balance.ConclusionsStem Cell Educator therapy is safe, and in individuals with moderate or severe T1D, a single treatment produces lasting improvement in metabolic control. Initial results indicate Stem Cell Educator therapy reverses autoimmunity and promotes regeneration of islet β cells. Successful immune modulation by CB-SCs and the resulting clinical improvement in patient status may have important implications for other autoimmune and inflammation-related diseases without the safety and ethical concerns associated with conventional stem cell-based approaches.Trial registrationClinicalTrials.gov number, NCT01350219.

Selective Induction of Dendritic Cells Using Granulocyte Macrophage-Colony Stimulating Factor, But Not fms-Like Tyrosine Kinase Receptor 3-Ligand, Activates Thyroglobulin-Specific CD4+/CD25+ T Cells and Suppresses Experimental Autoimmune Thyroiditis

fms-like tyrosine kinase receptor 3-ligand (Flt3-L) and GM-CSF cause expansion of different subsets of dendritic cells and skew the immune response toward predominantly Th1 and Th2 type, respectively. In the present study, we investigated their effects on experimental autoimmune thyroiditis in CBA/J mice. Relative to mouse thyroglobulin (mTg) immunized controls, mTg-immunized mice treated with Flt3-L showed more severe thyroiditis characterized by enhanced lymphocytic infiltration of the thyroid, and IFN-γ and IL-2 production. In contrast, mice treated with GM-CSF, either before or after immunization with mTg, showed suppressed T cell response to mTg and failed to develop thyroiditis. Lymphocytes from these mice, upon activation with mTg in vitro, produced higher levels of IL-4 and IL-10. Additionally, GM-CSF-treated mice showed an increase in the frequency of CD4+/CD25+ T cells, which suppressed the mTg-specific T cell response. Neutralization of IL-10, but not IL-4, or depletion of CD4+/CD25+ cells resulted in increased mTg-specific in vitro T cell proliferation suggesting that IL-10 produced by the Ag-specific CD4+/CD25+ regulatory T cells might be critical for disease suppression. These results indicate that skewing immune response toward Th2, through selective activation of dendritic cells using GM-CSF, may have therapeutic potential in Th1 dominant autoimmune diseases including Hashimoto’s thyroiditis.

Targeted CTLA-4 Engagement Induces CD4+CD25+CTLA-4high T Regulatory Cells with Target (Allo)antigen Specificity

CTLA-4 (CD152) is actively involved in down-regulating T cell activation and maintaining lymphocyte homeostasis. Our earlier studies showed that targeted engagement of CTLA-4 can down-modulate T cell response and suppress allo- and autoimmune responses. In this study, we report that targeted CTLA-4 engagement can induce immune tolerance to a specific target through selective induction of an Ag-specific CD4+CD25+CTLA-4high regulatory T cell (Treg cell) population. Allogeneic cells coated with anti-CTLA-4 Ab induced immune hyporesponsiveness through suppression of proinflammatory cytokines IFN-γ and IL-2, and up-regulation of the regulatory cytokines IL-10, TGF-β1, and IL-4, presumably through the engagement of CTLA-4 on activated T cells. Although rechallenge with alloantigen failed to break the unresponsiveness, a transient recovery from tolerance was observed in the presence of high concentrations of exogenous IL-2, saturating concentrations of neutralizing anti-TGF-β1 and anti-IL-10 Abs, and blocking anti-CTLA-4 Ab, and upon depletion of CD4+CD25+ Treg cells. The CD4+CD25+CTLA-4high Treg cells from tolerant mice suppressed the effector function of CD25− T cells from Ag-primed mice. Adoptive transfer of these Treg cells into Ag-primed mice resulted in a significantly reduced alloantigen-specific response. Further characterization demonstrated that the Treg cells with memory phenotype (CD62L−) were more potent in suppressing the alloantigen-specific T cell response. These results strongly support that the targeted engagement of CTLA-4 has therapeutic potential for the prevention of transplant rejection.

Living related small bowel transplantation: Donor surgical technique

Objective:To describe a standardized technique for ileal graft procurement in the setting of living related bowel transplantation. Summary Background Data:Living donor transplantation has been successfully developed for kidney, liver, pancreas, and lung transplantation. More recently, living related small bowel transplantation (LR-SBTx) has been developed with the aim of expanding the pool of intestinal graft donors and reducing the mortality in patients on the waiting list. To date, a total of 25 LR-SBTx worldwide have been reported to the international registry. We herein report the largest single center experience. Methods:A segment of ileum, 150 to 200 cm, is resected 20 cm proximal to the ileocecal valve (ICV), which is always preserved. The arterial inflow is given by the terminal branch of the superior mesenteric artery and venous outflow by a proximal segment of the superior mesenteric vein. The entire bowel is measured intraoperatively and at least 60% of intestine length is left in the donor. Results:Since 1998, we have performed 9 terminal ileum resections for small bowel donation. None of the donors has experienced persistent alteration of bowel habits or malabsorption; only 1 minor wound complication has occurred. Conclusions:Terminal ileal resection with preservation of the ICV seems to assure fast functional recovery of the donor and has minimal postoperative complications.

Short-term outcome in the first 10 morbidly obese adolescent patients in the FDA-approved trial for laparoscopic adjustable gastric banding

Background: We received the LAP-BAND Investigational Device Exemption (IDE) from the US Food and Drug Administration in December 2004 to conduct a prospective longitudinal trial examining the safety and efficacy of laparoscopic adjustable gastric banding (LAGB) in morbidly obese adolescents ages 14 to 17 years. Objectives: To report the short-term results of LAGB in the first 10 adolescents with complete 9 months of follow-up. Patients and Methods: Baseline characteristics and outcome data were analyzed in 10 patients enrolled between March 2005 and February 2006. Results: All of the patients were girls. Their mean body mass index (±SD) was 50 ± 13 kg/m2, and excess weight was 171 ± 79 pounds. Comorbidities included depression (3 patients), sleep apnea (3), hypertension (6), dyslipidemia (7), insulin resistance (9), metabolic syndrome (9), and steatohepatitis (in 4 of 5 patients with liver biopsy). Operative time was 45 ± 9 minutes, and discharges were within 23 hours of surgery. Band-related complications were as follows: 2 dehydration, 1 pouch dilation, and 1 port revision. All of the patients lost weight, with a 9-month excess weight loss of 30% ± 16% (range 14%–57%). Hypertension and the metabolic syndrome were resolved in 100% of patients (P = 0.04) and 80% of the patients (P = 0.01), respectively, along with significant improvement in the Pediatric Quality of Life and Beck Depression Inventory scores and a trend toward improvement in high-density lipoprotein cholesterol abnormalities (P = 0.08). Conclusions: At short-term follow-up, weight loss occurred with minimal complications, leading to early resolution of major obesity-related comorbidities. Continued evaluation of the long-term safety and efficacy of LAGB as a surgical adjunct to a comprehensive obesity treatment program is warranted.

Human cord blood stem cell-modulated regulatory T lymphocytes reverse the autoimmune-caused type 1 diabetes in nonobese diabetic (NOD) mice.

Background The deficit of pancreatic islet β cells caused by autoimmune destruction is a crucial issue in type 1 diabetes (T1D). It is essential to fundamentally control the autoimmunity for treatment of T1D. Regulatory T cells (Tregs) play a pivotal role in maintaining self-tolerance through their inhibitory impact on autoreactive effector T cells. An abnormality of Tregs is associated with initiation of progression of T1D. Methodology/Principal Findings Here, we report that treatment of established autoimmune-caused diabetes in NOD mice with purified autologous CD4+CD62L+ Tregs co-cultured with human cord blood stem cells (CB-SC) can eliminate hyperglycemia, promote islet β-cell regeneration to increase β-cell mass and insulin production, and reconstitute islet architecture. Correspondingly, treatment with CB-SC-modulated CD4+CD62L+ Tregs (mCD4CD62L Tregs) resulted in a marked reduction of insulitis, restored Th1/Th2 cytokine balance in blood, and induced apoptosis of infiltrated leukocytes in pancreatic islets. Conclusions/Significance These data demonstrate that treatment with mCD4CD62L Tregs can reverse overt diabetes, providing a novel strategy for the treatment of type 1 diabetes as well as other autoimmune diseases.

Absence of IL-4, and Not Suppression of the Th2 Response, Prevents Development of Experimental Autoimmune Graves’ Disease

In autoimmune Graves’ disease (GD), autoantibodies bind to the thyrotropin receptor (TSHR) and cause hyperthyroidism. We studied the effects of fms-like tyrosine kinase receptor 3 ligand (Flt3-L) or GM-CSF treatment on the development of experimental autoimmune GD (EAGD) in mice, a slowly progressing Ab-mediated organ-specific autoimmune disease of the thyroid induced by immunization with syngeneic cells expressing TSHR. Flt3-L and GM-CSF treatment resulted in up-regulation of CD8a+ and CD8a− dendritic cells, and skewing of cytokine and immune responses to TSHR in favor of Th1 and Th2, respectively. However, this skewing did not persist until the later stages, and thus failed to affect the course or severity of the disease. To determine whether the total absence of either IL-4 or IFN-γ could affect the development of EAGD, we immunized wild-type, IFN-γ−/− and IL-4−/− BALB/c mice with TSHR. Nearly 100% of the wild-type and IFN-γ−/− mice developed EAGD with optimal TSHR-specific immune responses, while IL-4−/− mice completely resisted disease and showed delayed and suboptimal pathogenic Ab response. These data demonstrated that skewing immune responses to TSHR, using either Flt3-L or GM-CSF, in favor of Th1 or Th2, respectively, may not be sufficient to alter the course of the disease, while the complete absence of IL-4, but not IFN-γ, can prevent the development of EAGD.

Living Related Segmental Bowel Transplantation: From Experimental to Standardized Procedure

Introduction:Living donor bowel transplantation has recently emerged as a valuable alternative to cadaver bowel transplant. We herein present our single-center experience with this procedure. Materials and Methods:From April 1998 to October 2004, 12 living donor intestinal transplants were performed in 11 patients (7 males, 4 females; average age, 26 years). Four of the patients were children under 5 years. A segment of distal ileum 150 to 180 cm long in pediatric recipients and 200 cm long in adult was used. The immunosuppressive protocol consisted of induction with thymoglobulin and maintenance with tacrolimus with or without mycophenolate mofetil and steroids. Results:All donors recovered well and did not experience any early or late complications. The overall 1- and 3-year patient survival was 82% with a graft survival of 75%. In the last 8 patients, transplanted after January 2000, the 1-year patient and graft survival has been 100% and 88%, respectively. The median hospital stay was 36 days (range, 13–290 days). During the first year after transplant only, the patient who received a totally mismatched graft experienced one episode of rejection (8%). All the surviving patients are currently supported by enteral diet without fluid requirements. Conclusions:Living donor bowel transplantation is a valuable strategy in the treatment of irreversible intestinal failure. The results have improved over the years thanks to increased experience of the team.

Enhanced Engagement of CTLA-4 Induces Antigen-Specific CD4+CD25+Foxp3+ and CD4+CD25− TGF-β1+ Adaptive Regulatory T Cells

CTLA-4 is a critical negative regulator of T cell response and is instrumental in maintaining immunological tolerance. In this article, we report that enhanced selective engagement of CTLA-4 on T cells by Ag-presenting dendritic cells resulted in the induction of Ag-specific CD4+CD25+Foxp3+ and CD4+CD25−TGF-β1+ adaptive Tregs. These cells were CD62Llow and hyporesponsive to stimulation with cognate Ag but demonstrated a superior ability to suppress Ag-specific effector T cell response compared with their CD62Lhigh counterparts. Importantly, treatment of mice with autoimmune thyroiditis using mouse thyroglobulin (mTg)-pulsed anti-CTLA-4 agonistic Ab-coated DCs, which results in a dominant engagement of CTLA-4 upon self-Ag presentation, not only suppressed thyroiditis but also prevented reemergence of the disease upon rechallenge with mTg. Further, the disease suppression was associated with significantly reduced mTg-specific T cell and Ab responses. Collectively, our results showed an important role for selective CTLA-4 signaling in the induction of adaptive Tregs and suggested that approaches that allow dominant CTLA-4 engagement concomitant with Ag-specific TCR ligation can be used for targeted therapy.

Preferential costimulation by CD80 results in IL-10-dependent TGF-beta1(+) -adaptive regulatory T cell generation.

Costimulatory ligands CD80 and CD86 have different binding preferences and affinities to their receptors, CD28 and CTLA-4. Earlier, we demonstrated that CD80 binds to CTLA-4 with higher affinity and has a role in suppressing T cell response. The current study demonstrates that not only did blockade of CD86 upon Ag presentation by bone marrow-derived dendritic cells (DC) to OVA-specific T cells result in induction of hyporesponsive T cells but also that these T cells could suppress the proliferative response of effector T cells. These T cells showed TGF-β1 on their surface and secreted TGF-β1 and IL-10 upon restimulation. Although blockade of CTLA-4 and neutralization of IL-10 profoundly inhibited the induction of these TGF-β1+ T cells, their ability to suppress the effector T cell proliferation was abrogated by neutralization of TGF-β1 alone. Induction of TGF-β1+ and IL-10+ T cells was found to be independent of natural CD4+CD25+ regulatory T cells, demonstrating that preferential ligation of CTLA-4 by CD80 induced IL-10 production by effector T cells, which in turn promoted the secretion of TGF-β1. Treatment of prediabetic NOD mice with islet β cell Ag-pulsed CD86−/− DCs, but not CD80−/− DCs, resulted in the induction of TGF-β1- and IL-10-producing cells, significant suppression of insulitis, and delay of the onset of hyperglycemia. These observations demonstrate not only that CD80 preferentially binds to CTLA-4 but also that interaction during Ag presentation can result in IL-10-dependent TGF-β1+ regulatory T cell induction, reinstating the potential of approaches to preferentially engage CTLA-4 through CD80 during self-Ag presentation in suppressing autoimmunity.