The state of the art of islet transplantation and cell therapy in type 1 diabetes

Effects of Mesenchymal Stem Cell-conditioned Media with Natural Immunomodulatory Agent Resveratrol on Type 1 Diabetes

BACKGROUND

Type 1 diabetes mellitus (T1DM) is a condition marked by elevated blood sugar levels and primarily recognized by the destruction of beta cells caused by an autoimmune attack, which is a significant characteristic of T1DM. Recent studies have demonstrated the regenerative potential of conditioned medium therapy. In light of this, the current research sought to assess the impact of Mesenchymal Stem Cell conditioned media (CM) and CM with resveratrol (CM+ Resveratrol) on the management of T1DM in Swiss albino mice. By leveraging and modifying existing conditioned medium therapy, this study aims to evaluate its effectiveness in treating T1DM.

MATERIALS & METHODS

Diabetes was induced in animals using the diabetes-inducing agent streptozotocin (STZ). The animals were then divided into five groups: Normal control, Disease Control, Resveratrol, Condition Media, and CM + Resveratrol. Treatments were given to the animals accordingly. The study period was 28 days. During this time, the animals were monitored for foodwater intake twice a week, blood glucose levels, and body weight. At the conclusion of the 28-day study period, biochemical estimations were performed for serum insulin levels, C-peptide levels, anti-inflammatory cytokines levels and pro-inflammatory cytokines levels. Additionally, histopathology of the pancreas was performed.

RESULTS

The test groups showed a significant decrease in blood glucose levels, an increase in Cpeptide levels, and a decrease in pro-inflammatory cytokine levels compared to the disease group. However, no statistically significant change within groups was observed in terms of serum insulin and anti-inflammatory cytokine levels. The improvement in diabetic symptoms, such as polyphagia, polydipsia, and weight loss, was observed in the treatment group, along with pancreatic regeneration, which indicated improved insulin secretion.

CONCLUSION

In the current investigation, we concluded that CM and CM+ Resveratrol, as natural immunomodulators, have the capacity to regenerate injured pancreatic beta cells and have antidiabetic action, together with immunomodulating impact. Nonetheless, future studies on this therapy appear to be promising.

Advanced therapy to cure diabetes: mission impossible is now possible?

Cell and Gene therapy are referred to as advanced therapies that represent overlapping fields of regenerative medicine. They have similar therapeutic goals such as to modify cellular identity, improve cell function, or fight a disease. These two therapeutic avenues, however, possess major differences. While cell therapy involves introduction of new cells, gene therapy entails introduction or modification of genes. Furthermore, the aim of cell therapy is often to replace, or repair damaged tissue, whereas gene therapy is used typically as a preventive approach. Diabetes mellitus severely affects the quality of life of afflicted individuals and has various side effects including cardiovascular, ophthalmic disorders, and neuropathy while putting enormous economic pressure on both the healthcare system and the patient. In recent years, great effort has been made to develop cutting-edge therapeutic interventions for diabetes treatment, among which cell and gene therapies stand out. This review aims to highlight various cell- and gene-based therapeutic approaches leading to the generation of new insulin-producing cells as a topmost "panacea" for treating diabetes, while deliberately avoiding a detailed molecular description of these approaches. By doing so, we aim to target readers who are new to the field and wish to get a broad helicopter overview of the historical and current trends of cell- and gene-based approaches in β-cell regeneration.

Hydrogel-based approaches to target hypersensitivity mechanisms underlying autoimmune disease

A robust adaptive immune response is essential for combatting pathogens. In the wrong context such as due to genetic and environmental factors, however, the same mechanisms crucial for self-preservation can lead to a loss of self-tolerance. Resulting autoimmunity manifests in the development of a host of organ-specific or systemic autoimmune diseases, hallmarked by aberrant immune responses and tissue damage. The prevalence of autoimmune diseases is on the rise, medical management of which focuses primarily on pharmacological immunosuppression that places patients at a risk of side effects, including opportunistic infections and tumorigenesis. Biomaterial-based drug delivery systems confer many opportunities to address challenges associated with conventional disease management. Hydrogels, in particular, can protect encapsulated cargo (drug or cell therapeutics) from the host environment, afford their presentation in a controlled manner, and can be tailored to respond to disease conditions or support treatment via multiplexed functionality. Moreover, localized delivery to affected sites by these approaches has the potential to concentrate drug action at the site, reduce off-target exposure, and enhance patient compliance by reducing the need for frequent administration. Despite their many benefits for the management of autoimmune disease, such biomaterial-based approaches focus largely on the downstream effects of hypersensitivity mechanisms and have a limited capacity to eradicate the disease. In contrast, direct targeting of mechanisms of hypersensitivity reactions uniquely enables prophylaxis or the arrest of disease progression by mitigating the basis of autoimmunity. One promising approach is to induce self-antigen-specific tolerance, which specifically subdues damaging autoreactivity while otherwise retaining the normal immune responses. In this review, we will discuss hydrogel-based systems for the treatment of autoimmune disease, with a focus on those that target hypersensitivity mechanisms head-on. As the field continues to advance, it will expand the range of therapeutic choices for people coping with autoimmune diseases, providing fresh prospects for better clinical outcomes and improved quality of life.

Efficacy of mesenchymal stromal cells in the treatment of type 1 diabetes: a systematic review

To investigate the efficacy of mesenchymal stromal cells in the treatment of type 1 diabetes. Articles about the effects of mesenchymal stromal cells for T1D were retrieved in PubMed, Web of Science, Embase, and the Cochrane Library databases up to July 2023. Additional relevant studies were manually searched through citations. HbA1c, FBG, PBG, insulin requirement and C-peptide were assessed. The risk of bias was evaluated with the ROB 2.0 and ROBINS-I tools. Six RCTs and eight nRCTs were included. Of the 14 studies included, two evaluated BM-MSCs, three evaluated UC-MSCs, five evaluated AHSCT, two evaluated CB-SCs, and two evaluated UC-SCs plus aBM-MNCs. At the end of follow-up, ten studies found that mesenchymal stromal cells improved glycemic outcomes in T1D, while the remaining four studies showed no significant improvement. Findings support the positive impacts observed from utilizing mesenchymal stromal cells in individuals with T1D. However, the overall methodological quality of the identified studies and findings is heterogeneous, limiting the interpretation of the therapeutic benefits of mesenchymal stromal cells in T1D. Methodically rigorous research is needed to further increase credibility.

Drug Integrating Amphiphilic Nano-Assemblies: 2. Spatiotemporal Distribution within Inflammation Sites

The need for chronic systemic immunosuppression, which is associated with unavoidable side-effects, greatly limits the applicability of allogeneic cell transplantation for regenerative medicine applications including pancreatic islet cell transplantation to restore insulin production in type 1 diabetes (T1D). Cell transplantation in confined sites enables the localized delivery of anti-inflammatory and immunomodulatory drugs to prevent graft loss by innate and adaptive immunity, providing an opportunity to achieve local effects while minimizing unwanted systemic side effects. Nanoparticles can provide the means to achieve the needed localized and sustained drug delivery either by graft targeting or co-implantation. Here, we evaluated the potential of our versatile platform of drug-integrating amphiphilic nanomaterial assemblies (DIANAs) for targeted drug delivery to an inflamed site model relevant for islet transplantation. We tested either passive targeting of intravenous administered spherical nanomicelles (nMIC; 20-25 nm diameter) or co-implantation of elongated nanofibrils (nFIB; 5 nm diameter and >1 μm length). To assess the ability of nMIC and nFIB to target an inflamed graft site, we used a lipophilic fluorescent cargo (DiD and DiR) and evaluated the in vivo biodistribution and cellular uptake in the graft site and other organs, including draining and non-draining lymph nodes, after systemic administration (nMIC) and/or graft co-transplantation (nFIB) in mice. Localized inflammation was generated either by using an LPS injection or by using biomaterial-coated islet-like bead implantation in the subcutaneous site. A cell transplant inflammation model was used as well to test nMIC- and nFIB-targeted biodistribution. We found that nMIC can reach the inflamed site after systemic administration, while nFIB remains localized for several days after co-implantation. We confirmed that DIANAs are taken up by different immune cell populations responsible for graft inflammation. Therefore, DIANA is a useful approach for targeted and/or localized delivery of immunomodulatory drugs to decrease innate and adaptive immune responses that cause graft loss after transplantation of therapeutic cells.

Indirect co-culture of islet cells in 3D biocompatible collagen/laminin scaffold with angiomiRs transfected mesenchymal stem cells

Diabetes is an autoimmune disease in which the pancreatic islets produce insufficient insulin. One of the treatment strategies is islet isolation, which may damage these cells as they lack vasculature. Biocompatible scaffolds are one of the efficient techniques for dealing with this issue. The current study is aimed to determine the effect of transfected BM-MSCS with angiomiR-126 and -210 on the survival and functionality of islets loaded into a 3D scaffold via laminin (LMN). AngiomiRs/Poly Ethylenimine polyplexes were transfected into bone marrow-mesenchymal stem cells (BM-MSCs), followed by 3-day indirect co-culturing with islets laden in collagen (Col)-based hydrogel scaffolds containing LMN. Islet proliferation and viability were significantly increased in LMN-containing scaffolds, particularly in the miRNA-126 treated group. Insulin gene expression was superior in Col scaffolds, especially, in the BM-MSCs/miRNA-126 treated group. VEGF was upregulated in the LMN-containing scaffolds in both miRNA-treated groups, specifically in the miRNA-210, leading to VEGF secretion. MiRNAs' target genes showed no downregulation in LMN-free scaffolds; while a drastic downregulation was seen in the LMN-containing scaffolds. The highest insulin secretion was recorded in the Oxidized dextran (Odex)/Col^LMN+ group with miRNA-126. LMN-containing biocompatible scaffolds, once combined with angiomiRs and their downstream effectors, promote islets survival and restore function, leading to enhanced angiogenesis and glycemic status.

Direct Reprogramming of Somatic Cells into Induced β-Cells: An Overview

The persistent shortage of insulin-producing islet mass or β-cells for transplantation in the ever-growing diabetic population worldwide is a matter of concern. To date, permanent cure to this medical complication is not available and soon after the establishment of lineage-specific reprogramming, direct β-cell reprogramming became a viable alternative for β-cell regeneration. Direct reprogramming is a straightforward and powerful technique that can provide an unlimited supply of cells by transdifferentiating terminally differentiated cells toward the desired cell type. This approach has been extensively used by multiple groups to reprogram non-β-cells toward insulin-producing β-cells. The β-cell identity has been achieved by various studies via ectopic expression of one or more pancreatic-specific transcription factors in somatic cells, bypassing the pluripotent state. This work highlights the importance of the direct reprogramming approaches (both integrative and non-integrative) in generating autologous β-cells for various applications. An in-depth understanding of the strategies and cell sources could prove beneficial for the efficient generation of integration-free functional insulin-producing β-cells for diabetic patients lacking endogenous β-cells.

Treating iPSC-Derived β Cells with an Anti-CD30 Antibody-Drug Conjugate Eliminates the Risk of Teratoma Development upon Transplantation

Insulin-producing cells derived from induced pluripotent stem cells (iPSCs) are promising candidates for β cell replacement in type 1 diabetes. However, the risk of teratoma formation due to residual undifferentiated iPSCs contaminating the differentiated cells is still a critical concern for clinical application. Here, we hypothesized that pretreatment of iPSC-derived insulin-producing cells with an anti-CD30 antibody−drug conjugate could prevent in vivo teratoma formation by selectively killing residual undifferentiated cells. CD30 is expressed in all human iPSCs clones tested by flow cytometry (n = 7) but not in iPSC-derived β cells (iβs). Concordantly, anti-CD30 treatment in vitro for 24 h induced a dose-dependent cell death (up to 90%) in human iPSCs while it did not kill iβs nor had an impact on iβ identity and function, including capacity to secrete insulin in response to stimuli. In a model of teratoma assay associated with iβ transplantation, the pretreatment of cells with anti-CD30 for 24 h before the implantation into NOD-SCID mice completely eliminated teratoma development (0/10 vs. 8/8, p < 0.01). These findings suggest that short-term in vitro treatment with clinical-grade anti-CD30, targeting residual undifferentiated cells, eliminates the tumorigenicity of iPSC-derived β cells, potentially providing enhanced safety for iPSC-based β cell replacement therapy in clinical scenarios.

Bioengineering the Vascularized Endocrine Pancreas: A Fine-Tuned Interplay Between Vascularization, Extracellular-Matrix-Based Scaffold Architecture, and Insulin-Producing Cells

Intrahepatic islet transplantation is a promising β-cell replacement strategy for the treatment of type 1 diabetes. Instant blood-mediated inflammatory reactions, acute inflammatory storm, and graft revascularization delay limit islet engraftment in the peri-transplant phase, hampering the success rate of the procedure. Growing evidence has demonstrated that islet engraftment efficiency may take advantage of several bioengineering approaches aimed to recreate both vascular and endocrine compartments either ex vivo or in vivo. To this end, endocrine pancreas bioengineering is an emerging field in β-cell replacement, which might provide endocrine cells with all the building blocks (vascularization, ECM composition, or micro/macro-architecture) useful for their successful engraftment and function in vivo. Studies on reshaping either the endocrine cellular composition or the islet microenvironment have been largely performed, focusing on a single building block element, without, however, grasping that their synergistic effect is indispensable for correct endocrine function. Herein, the review focuses on the minimum building blocks that an ideal vascularized endocrine scaffold should have to resemble the endocrine niche architecture, composition, and function to foster functional connections between the vascular and endocrine compartments. Additionally, this review highlights the possibility of designing bioengineered scaffolds integrating alternative endocrine sources to overcome donor organ shortages and the possibility of combining novel immune-preserving strategies for long-term graft function.

Viability and Functionality of Neonatal Porcine Islet-like Cell Clusters Bioprinted in Alginate-Based Bioinks

The transplantation of pancreatic islets can prevent severe long-term complications in diabetes mellitus type 1 patients. With respect to a shortage of donor organs, the transplantation of xenogeneic islets is highly attractive. To avoid rejection, islets can be encapsulated in immuno-protective hydrogel-macrocapsules, whereby 3D bioprinted structures with macropores allow for a high surface-to-volume ratio and reduced diffusion distances. In the present study, we applied 3D bioprinting to encapsulate the potentially clinically applicable neonatal porcine islet-like cell clusters (NICC) in alginate-methylcellulose. The material was additionally supplemented with bovine serum albumin or the human blood plasma derivatives platelet lysate and fresh frozen plasma. NICC were analysed for viability, proliferation, the presence of hormones, and the release of insulin in reaction to glucose stimulation. Bioprinted NICC are homogeneously distributed, remain morphologically intact, and show a comparable viability and proliferation to control NICC. The number of insulin-positive cells is comparable between the groups and over time. The amount of insulin release increases over time and is released in response to glucose stimulation over 4 weeks. In summary, we show the successful bioprinting of NICC and could demonstrate functionality over the long-term in vitro. Supplementation resulted in a trend for higher viability, but no additional benefit on functionality was observed.

Treating Type 1 Diabetes by Pancreas Transplant Alone: A Cohort Study on Actual Long-term (10 Years) Efficacy and Safety

BACKGROUND

Physiologically regulated insulin secretion and euglycemia are achievable in type 1 diabetes (T1D) by islet or pancreas transplantation. However, pancreas transplant alone (PTA) remains a debated approach, with uncertainties on its relative benefits and risks. We determined the actual long-term (10 y) efficacy and safety of PTA in carefully characterized T1D subjects.

METHODS

This is a single-center, cohort study in 66 consecutive T1D subjects who received a PTA between April 2001 and December 2007, and were then all followed until 10 y since transplant. Main features evaluated were patient survival, pancreas graft function, C-peptide levels, glycemic parameters, and the function of the native kidneys.

RESULTS

Ten-year actual patient survival was 92.4%. Optimal (insulin independence) or good (minimal insulin requirement) graft function was observed in 57.4% and 3.2% of patients, respectively. Six (9.0%) patients developed stage 5 or 4 chronic kidney disease. In the remaining individuals bearing a successful PTA, estimated glomerular filtration rate (eGFR) decline per year was -2.29 ± 2.69 mL/min/1.73 m2. Reduction of eGFR at 1 y post-PTA was higher in those with pre-PTA hyperfiltration and higher HbA1c concentrations; eGFR changes afterward significantly correlated with diabetes duration. In recipients with normoglycemia at 10 y, 74% of normoalbuminuric or microalbuminuric subjects pre-PTA remained stable, and 26% progressed toward a worse stage; conversely, in 62.5% of the macroalbuminuric individuals albuminuria severity regressed.

CONCLUSIONS

These long-term effects of PTA on patient survival, graft function, and the native kidneys support PTA as a suitable approach to treat diabetes in selected T1D patients.

Localized drug delivery graphene bioscaffolds for cotransplantation of islets and mesenchymal stem cells

In the present work, we developed, characterized, and tested an implantable graphene bioscaffold which elutes dexamethasone (Dex) that can accommodate islets and adipose tissue–derived mesenchymal stem cells (AD-MSCs). In vitro studies demonstrated that islets in graphene–0.5 w/v% Dex bioscaffolds had a substantial higher viability and function compared to islets in graphene-alone bioscaffolds or islets cultured alone (P < 0.05). In vivo studies, in which bioscaffolds were transplanted into the epididymal fat pad of diabetic mice, demonstrated that, when islet:AD-MSC units were seeded into graphene–0.5 w/v% Dex bioscaffolds, this resulted in complete restoration of glycemic control immediately after transplantation with these islets also showing a faster response to glucose challenges (P < 0.05). Hence, this combination approach of using a graphene bioscaffold that can be functionalized for local delivery of Dex into the surrounding microenvironment, together with AD-MSC therapy, can significantly improve the survival and function of transplanted islets.

Felix dies natalis, insulin… ceterum autem censeo "beta is better"

One hundred years after its discovery, insulin remains the life-saving therapy for many patients with diabetes. It has been a 100-years-old success story thanks to the fact that insulin therapy has continuously integrated the knowledge developed over a century. In 1982, insulin becomes the first therapeutic protein to be produced using recombinant DNA technology. The first "mini" insulin pump and the first insulin pen become available in 1983 and 1985, respectively. In 1996, the first generation of insulin analogues were produced. In 1999, the first continuous glucose-monitoring device for reading interstitial glucose was approved by the FDA. In 2010s, the ultra-long action insulins were introduced. An equally exciting story developed in parallel. In 1966. Kelly et al. performed the first clinical pancreas transplant at the University of Minnesota, and now it is a well-established clinical option. First successful islet transplantations in humans were obtained in the late 1980s and 1990s. Their ability to consistently re-establish the endogenous insulin secretion was obtained in 2000s. More recently, the possibility to generate large numbers of functional human β cells from pluripotent stem cells was demonstrated, and the first clinical trial using stem cell-derived insulin producing cell was started in 2014. This year, the discovery of this life-saving hormone turns 100 years. This provides a unique opportunity not only to celebrate this extraordinary success story, but also to reflect on the limits of insulin therapy and renew the commitment of the scientific community to an insulin free world for our patients.

Recent Advances in the Generation of β-Cells from Induced Pluripotent Stem Cells as a Potential Cure for Diabetes Mellitus

Diabetes mellitus (DM) is a group of metabolic disorders characterized by high blood glucose levels due to insufficient insulin secretion, insulin action, or both. The present-day solution to diabetes mellitus includes regular administration of insulin, which brings about many medical complications in diabetic patients. Although islet transplantation from cadaveric subjects was proposed to be a permanent cure, the increased risk of infections, the need for immunosuppressive drugs, and their unavailability had restricted its use. To overcome this, the generation of renewable and transplantable β-cells derived from autologous induced pluripotent stem cells (iPSCs) has gained enormous interest as a potential therapeutic strategy to treat diabetes mellitus permanently. To date, extensive research has been undertaken to derive transplantable insulin-producing β-cells (iβ-cells) from iPSCs in vitro by recapitulating the in vivo developmental process of the pancreas. This in vivo developmental process relies on transcription factors, signaling molecules, growth factors, and culture microenvironment. This review highlights the various factors facilitating the generation of mature β-cells from iPSCs. Moreover, this review also describes the generation of pancreatic progenitors and β-cells from diabetic patient-specific iPSCs, exploring the potential of the diabetes disease model and drug discovery. In addition, the applications of genome editing strategies have also been discussed to achieve patient-specific diabetes cell therapy. Last, we have discussed the current challenges and prospects of iPSC-derived β-cells to improve the relative efficacy of the available treatment of diabetes mellitus.

Pancreas transplant versus islet transplant versus insulin pump therapy: in which patients and when?

PURPOSE OF REVIEW

The aim of the present review is to gather recent reports on the use of pancreas and islet transplantation and conventional insulin therapy for treating patients experiencing diabetes and its related complications. The present review directs attention to the current status, challenges and perspectives of these therapies and sheds light on potential future cellular therapies.

RECENT FINDINGS

The risks and benefits of diabetes treatment modalities continue to evolve, altering the risk versus benefit calculation for patients. As continuous subcutaneous insulin infusion and monitoring technologies demonstrate increasing effectiveness in achieving better diabetes control and reducing hypoglycemia frequency, so are pancreas and islet transplantation improving and becoming more effective and safer. Both beta-cell replacement therapies, however, are limited by a dependence on immunosuppression and a shortage of cadaver donors, restricting more widespread and safer deployment. Based on the effectiveness of clinical beta-cell replacement for lengthening lifespan and improving quality of life, scientists are aggressively investigating alternative cell sources, transplant platforms, and means of preventing immunological damage of transplanted cells to overcome these principle limitations.

SUMMARY

Essential goals of diabetes therapy are euglycemia, avoidance of hypoglycemia, and prevention or stabilization of end-organ damage. With these goals in mind, all therapeutic options should be considered.

The effect of liver donors' age, gender and metabolic state on pancreatic lineage activation

Autologous cells replacement therapy by liver to pancreas transdifferentiation (TD) allows diabetic patients to be also the donors of their own therapeutic tissue. Aim: To analyze whether the efficiency of the process is affected by liver donors' heterogeneity with regard to age, gender and the metabolic state. Materials & methods: TD of liver cells derived from nondiabetic and diabetic donors at different ages was characterized at molecular and cellular levels, in vitro. Results: Neither liver cells proliferation nor the propagated cells TD efficiency directly correlate with the age (3-60 years), gender or the metabolic state of the donors. Conclusion: Human liver cells derived from a wide array of ages and metabolic states can be used for autologous cells therapies for diabetics.

Targeting CXCR1/2 Does Not Improve Insulin Secretion After Pancreatic Islet Transplantation: A Phase 3, Double-Blind, Randomized, Placebo-Controlled Trial in Type 1 Diabetes

OBJECTIVE

Reparixin is an inhibitor of CXCR1/2 chemokine receptor shown to be an effective anti-inflammatory adjuvant in a pilot clinical trial in allotransplant recipients.

RESEARCH DESIGN AND METHODS

A phase 3, multicenter, randomized, double-blind, parallel-assignment study (NCT01817959) was conducted in recipients of islet allotransplants randomized (2:1) to reparixin or placebo in addition to immunosuppression. Primary outcome was the area under the curve (AUC) for C-peptide during the mixed-meal tolerance test at day 75 ± 5 after the first and day 365 ± 14 after the last transplant. Secondary end points included insulin independence and standard measures of glycemic control.

RESULTS

The intention-to-treat analysis did not show a significant difference in C-peptide AUC at both day 75 (27 on reparixin vs. 18 on placebo, P = 0.99) and day 365 (24 on reparixin vs. 15 on placebo, P = 0.71). There was no statistically significant difference between treatment groups at any time point for any secondary variable. Analysis of patient subsets showed a trend for a higher percentage of subjects retaining insulin independence for 1 year after a single islet infusion in patients receiving reparixin as compared with patients receiving placebo (26.7% vs. 0%, P = 0.09) when antithymocyte globulin was used as induction immunosuppression.

CONCLUSIONS

In this first double-blind randomized trial, islet transplantation data obtained with reparixin do not support a role of CXCR1/2 inhibition in preventing islet inflammation-mediated damage.

Magnetic Retrieval of Encapsulated Beta Cell Transplants from Diabetic Mice Using Dual-Function MRI Visible and Retrievable Microcapsules

Encapsulated beta cell transplantation offers a potential cure for a subset of diabetic patients. Once transplanted, beta cell grafts can help to restore glycemic control; however, locating and retrieving cells in the event of graft failure may pose a surgical challenge. Here, a dual-function nanoparticle-loaded hydrogel microcapsule is developed that enables graft retrieval under an applied magnetic field. Additionally, this system facilitates graft localization via magnetic resonance imaging (MRI), and graft isolation from the immune system. Iron oxide nanoparticles encapsulated within alginate hydrogel capsules containing viable islets are transplanted and the in vitro and in vivo retrieval of capsules containing nanoparticles functionalized with various ligands are compared. Capsules containing islets co-encapsulated with COOH-coated nanoparticles restore normal glycemia in immunocompetent diabetic mice for at least 6 weeks, can be visualized using MRI, and are retrievable in a magnetic field. Application of a magnetic field for 90 s via a magnetically assisted retrieval device facilitates rapid retrieval of up to 94% (±3.1%) of the transplant volume 24 h after surgical implantation. This strategy aids monitoring of cell-capsule locations in vivo, facilitates graft removal at the end of the transplant lifetime, and may be applicable to many encapsulated cell transplant systems.

Standardized GMP-compliant scalable production of human pancreas organoids

Background

Organoids are three-dimensional in vitro-grown cell clusters that recapitulate key features of native organs. In regenerative medicine, organoid technology represents a promising approach for the replacement of severely damaged organs, such as the pancreas in patients with type 1 diabetes. Isolation human pancreas organoids (hPOs) in chemically defined serum-free culture media would be a major milestone for this approach.

Methods

Starting from discarded pancreatic tissues, we developed a large-scale process for obtaining clinically relevant quantities of undifferentiated organoids, obviating enzymatic digestion and operator-dependent pancreatic ducts picking steps. hPO identity was characterized by molecular and flow cytometry analysis.

Results

This work demonstrates that it is possible to obtain a large-scale production of organoids. We introduced some innovations in the isolation, expansion, and freezing of hPOs from five donors. First of all, the choice of the starting material (islet-depleted pancreas) that allows obtaining a high quantity of hPOs at low passages. On the other hand, we introduced mechanical dissociation and we eliminated the picking step to exclude the operator-depending steps, without affecting the success of the culture (100% success rate). Another important improvement was to replace R-spondin-1 (Rspo1) conditioned medium with Rspo1 recombinant molecule to obtain a well-defined composition of the expansion medium. Finally, we implemented a GMP-compliant freezing protocol. hPOs showed exponential growth with diameter and area that increased three- and eight-fold in 7 days, respectively. Immunophenotypic profile and gene expression analysis revealed that hPOs were composed of ductal (82.33 ± 8.37%), acinar (2.80 ± 1.25%) cells, and pancreatic progenitors (5.81 ± 2.65%).

Conclusion

This work represents a milestone for a GMP-compliance hPO production and, ultimately, their clinical application as a type 1 diabetes therapy.

The effect of human wharton's jelly-derived mesenchymal stem cells on MC4R, NPY, and LEPR gene expression levels in rats with streptozotocin-induced diabetes

OBJECTIVES

Type 1 diabetes (T1D) is an autoimmune disease resulting from inflammatory destruction of islets β-cells. Nowadays, progress in cell therapy, especially mesenchymal stem cells (MSCs) proposes numerous potential remedies for T1D. We aimed to investigate the combination therapeutic effect of these cells with insulin and metformin on neuropeptide Y, melanocortin-4 receptor, and leptin receptor genes expression in TID.

MATERIALS AND METHODS

One hundreds male rats were randomly divided into seven groups: the control, diabetes, insulin (Ins.), insulin+metformin (Ins.Met.), Wharton's Jelly-derived MSCs (WJ-MSCs), insulin+metformin+WJ-MSCs (Ins.Met.MSCs), and insulin+WJ-MSCs (Ins.MSCs). Treatment was performed from the first day after diagnosis as diabetes. Groups of the recipient WJ-MSCs were intraportally injected with 2× 10⁶ MSCs/kg at the 7th and 28th days of study. Fasting blood sugar was monitored and tissues and genes analysis were performed.

RESULTS

The blood glucose levels were slightly decreased in all treatment groups within 20th and 45th days compared to the diabetic group. The C-peptide level enhanced in these groups compared to the diabetic group, but this increment in Ins.MSCs group on the 45th days was higher than other groups. The expression level of melanocortin-4 receptor and leptin receptor genes meaningfully up-regulated in the treatment groups, while the expression of neuropeptide Y significantly down-regulated in the treatment group on both times of study.

CONCLUSION

Our data exhibit that infusion of MSCs and its combination therapy with insulin might ameliorate diabetes signs by changing the amount of leptin and subsequent changes in the expression of neuropeptide Y and melanocortin-4 receptor.

Role of the PD-1/PD-L1 Dyad in the Maintenance of Pancreatic Immune Tolerance for Prevention of Type 1 Diabetes

The human pancreas, like almost all organs in the human body, is immunologically tolerated despite the presence of innate and adaptive immune cells that promptly mediate protective immune responses against pathogens in situ. The PD-1/PD-L1 inhibitory pathway seems to play a key role in the maintenance of immune tolerance systemically and within the pancreatic tissue. Tissue resident memory T cells (TRM), T regulatory cells (Treg), macrophages and even β cells exhibit PD-1 or PD-L1 expression that contributes in controlling pancreatic immune homeostasis and tolerance. Dysregulation of the PD-1/PD-L1 axis as shown by animal studies and our recent experience with checkpoint inhibitory blockade in humans can lead to immune dysfunctions leading to chronic inflammatory disease and to type 1 diabetes (T1D) in genetically susceptible individuals. In this review, we discuss the role of the PD-1/PD-L1 axis in pancreatic tissue homeostasis and tolerance, speculate how genetic and environmental factors can regulate the PD-1/PD-L1 pathway, and discuss PD-1/PD-L1-based therapeutic approaches for pancreatic islet transplantation and T1D treatment.

Microencapsulated islet-like microtissues with toroid geometry for enhanced cellular viability

Transplantation of immuno-isolated islets is a promising strategy to restore insulin-secreting function in patients with Type 1 diabetes. However, the clinical translation of this treatment approach remains elusive due to the loss of islet viability resulting from hypoxia at the avascular transplantation site. To address this challenge, we designed non-spherical islet-like microtissues and investigated the effect of their geometries on cellular viability. Insulin-secreting microtissues with different shapes were fabricated by assembly of monodispersed rat insulinoma beta cells on micromolded nonadhesive hydrogels. Our study quantitatively demonstrated that toroid microtissues exhibited enhanced cellular viability and metabolic activity compared to rod and spheroid microtissues with the same volume. At a similar level of cellular viability, toroid geometry facilitated efficient packing of more cells into each microtissue than rod and spheroid geometries. In addition, toroid microtissues maintained the characteristic glucose-responsive insulin secretion of rat insulinoma beta cells. Furthermore, toroid microtissues preserved their geometry and structural integrity following their microencapsulation in immuno-isolatory alginate hydrogel. Our study suggests that adopting toroid geometry in designing therapeutic microtissues potentially reduces mass loss of cellular grafts and thereby may improve the performance of transplanted islets towards a clinically viable cure for Type 1 diabetes. STATEMENT OF SIGNIFICANCE: Transplantation of therapeutic cells is a promising strategy for the treatment of a wide range of hormone or protein-deficiency diseases. However, the clinical application of this approach is hindered by the loss of cell viability and function at the avascular transplantation site. To address this challenge, we fabricated hydrogel-encapsulated islet-like microtissues with non-spheroidal geometry and optimal surface-to-volume ratio. This study demonstrated that the viability of therapeutic cells can be significantly increased solely by redesigning the microtissue configuration without requiring any additional biochemical or operational accessories. This study suggests that the adoption of toroid geometry provides a possible avenue to improve the long-term survival of transplanted therapeutic cells and expedite the translation of cell-based therapy towards clinical application.

Islet Allotransplantation in the Bone Marrow of Patients With Type 1 Diabetes: A Pilot Randomized Trial

BACKGROUND

Results in murine and nonhuman primate suggested that the bone marrow (BM) might be an alternative site for pancreatic islet transplantation.

METHODS

We report the results of 2 clinical studies in patients with type 1 diabetes receiving an intra-BM allogeneic islet transplantation: a feasibility study in patients with hepatic contraindications for liver islet allotransplantation receiving a single intra-BM islet infusion (n = 4) and a pilot randomized trial (1:1 allocation using blocks of size 6) in which patients were randomized to receive islets into either the liver (n = 6) or BM (n = 3) to evaluate islet transplant function and survival.

RESULTS

We observed no adverse events related to the intrabone injection procedure or the presence of islets in the BM. None of the recipient of an intra-BM allogeneic islet transplantation had a primary nonfunction, as shown by measurable posttransplantation C-peptide levels and histopathological evidence of insulin-producing cells or molecular markers of endocrine tissue in BM biopsy samples collected during follow-up. All patients receiving islets in the BM except 1 lost islet function during the first 4 months after infusion (2 with an early graft loss). Based on biopsies and immunomonitoring, we concluded that the islet loss was primarily caused by the recurrence of autoimmunity.

CONCLUSIONS

Bone marrow is not a suitable alternative site for pancreatic islet allotransplantation in patients with type 1 diabetes.

Bioactive nanoparticle embedded microcapsules for improving the efficacy of type I diabetes therapy

In order to overcome the side effects of pancreatic transplantation and insulin injection treatment for type I diabetes, we established a drug delivery system employing nanoparticle embedded microcapsules (NEMs). The system co-encapsulated chitosan nanoparticles with γ-aminobutyric acid and β-TC-6 cells for combined drug and cell therapy in diabetes mellitus (DM). The NEMs, which were formed via high-voltage electrostatic method, had an excellent sphericity with a smooth surface. The average size NEM was 245.52 ± 22.00 μm, which indicated a good size for cell encapsulation. Haemolysis rate of NEMs at concentrations of 100, 200 or 300 mg/mL were all below 5%. Relative viability rates of L929 cells with the same concentrations at 24, 48 or 72 h were all above 80%. We implanted bioactive NEMs into type 1 DM mice to evaluate the effect of the combined therapy. The level of blood glucose in the group receiving the combined therapy decreased during the first 2 weeks of treatment. During the next week, the level of blood glucose stayed in a safe range. Body weight continuously increased during the postoperative period after combined therapy group. Oral glucose tolerance test (OGTT) performed after 24 d showed that the level of blood glucose combined therapy reached the maximum peak of 13.04 mmol/L, lower than 16.56 mmol/L for the cell therapy group. This primary study indicated that microencapsulation technology and combined therapy are promising for the treatment of type I diabetes mellitus.

Development of a microchannel emulsification process for pancreatic beta cell encapsulation

In this study, we developed a high‐throughput microchannel emulsification process to encapsulate pancreatic beta cells in monodisperse alginate beads. The process builds on a stirred emulsification and internal gelation method previously adapted to pancreatic cell encapsulation. Alginate bead production was achieved by flowing a 0.5–2.5% alginate solution with cells and CaCO₃ across a 1‐mm thick polytetrafluoroethylene plate with 700 × 200 μm rectangular straight‐through channels. Alginate beads ranging from 1.5–3 mm in diameter were obtained at production rates exceeding 140 mL/hr per microchannel. Compared to the stirred emulsification process, the microchannel emulsification beads had a narrower size distribution and demonstrated enhanced compressive burst strength. Both microchannel and stirred emulsification beads exhibited homogeneous profiles of 0.7% alginate concentration using an initial alginate solution concentration of 1.5%. Encapsulated beta cell viability of 89 ± 2% based on live/dead staining was achieved by minimizing the bead residence time in the acidified organic phase fluid. Microchannel emulsification is a promising method for clinical‐scale pancreatic beta cell encapsulation as well as other applications in the pharmaceutical, food, and cosmetic industries.

Therapies for Type 1 Diabetes: Current Scenario and Future Perspectives

Type 1 diabetes (T1D) is caused by autoimmune destruction of insulin-producing β cells located in the endocrine pancreas in areas known as islets of Langerhans. The current standard-of-care for T1D is exogenous insulin replacement therapy. Recent developments in this field include the hybrid closed-loop system for regulated insulin delivery and long-acting insulins. Clinical studies on prediction and prevention of diabetes-associated complications have demonstrated the importance of early treatment and glucose control for reducing the risk of developing diabetic complications. Transplantation of primary islets offers an effective approach for treating patients with T1D. However, this strategy is hampered by challenges such as the limited availability of islets, extensive death of islet cells, and poor vascular engraftment of islets post-transplantation. Accordingly, there are considerable efforts currently underway for enhancing islet transplantation efficiency by harnessing the beneficial actions of stem cells. This review will provide an overview of currently available therapeutic options for T1D, and discuss the growing evidence that supports the use of stem cell approaches to enhance therapeutic outcomes.

The role of the vasculature niche on insulin-producing cells generated by transdifferentiation of adult human liver cells

Background

Insulin-dependent diabetes is a multifactorial disorder that could be theoretically cured by functional pancreatic islets and insulin-producing cell (IPC) implantation. Regenerative medicine approaches include the potential for growing tissues and organs in the laboratory and transplanting them when the body cannot heal itself. However, several obstacles remain to be overcome in order to bring regenerative medicine approach for diabetes closer to its clinical implementation; the cells generated in vitro are typically of heterogenic and immature nature and the site of implantation should be readily vascularized for the implanted cells to survive in vivo. The present study addresses these two limitations by analyzing the effect of co-implanting IPCs with vasculature promoting cells in an accessible site such as subcutaneous. Secondly, it analyzes the effects of reconstituting the in vivo environment in vitro on the maturation and function of insulin-producing cells.

Methods

IPCs that are generated by the transdifferentiation of human liver cells are exposed to the paracrine effects of endothelial colony-forming cells (ECFCs) and human bone marrow mesenchymal stem cells (MSCs), which are the “building blocks” of the blood vessels. The role of the vasculature on IPC function is analyzed upon subcutaneous implantation in vivo in immune-deficient rodents. The paracrine effects of vasculature on IPC maturation are analyzed in culture.

Results

Co-implantation of MSCs and ECFCs with IPCs led to doubling the survival rates and a threefold increase in insulin production, in vivo. ECFC and MSC co-culture as well as conditioned media of co-cultures resulted in a significant increased expression of pancreatic-specific genes and an increase in glucose-regulated insulin secretion, compared with IPCs alone. Mechanistically, we demonstrate that ECFC and MSC co-culture increases the expression of CTGF and ACTIVINβα, which play a key role in pancreatic differentiation.

Conclusions

Vasculature is an important player in generating regenerative medicine approaches for diabetes. Vasculature displays a paracrine effect on the maturation of insulin-producing cells and their survival upon implantation. The reconstitution of the in vivo niche is expected to promote the liver-to-pancreas transdifferentiation and bringing this cell therapy approach closer to its clinical implementation.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1157-5) contains supplementary material, which is available to authorized users.

Paving the way for successful islet encapsulation

Type 1 diabetes mellitus (T1DM) is a disorder that decimates pancreatic β-cells which produce insulin. Direct pancreatic islet transplantation cannot serve as a widespread therapeutic modality owing to the need for lifelong immunosuppression and donor shortage. Therefore, several encapsulation techniques have been developed to enclose the islets in semipermeable vehicles that will allow oxygen and nutrient input as well as insulin, other metabolites and waste output, while accomplishing immunoisolation. Although encapsulation technology continues to face significant obstacles, recent advances in material science, stem cell biology and immunology potentially serve as pathways to success. This review summarizes the accomplishments of the past 5 years.

Neuroligin-2-derived peptide-covered polyamidoamine-based (PAMAM) dendrimers enhance pancreatic β-cells' proliferation and functions

Pancreatic β-cell membranes and presynaptic areas of neurons contain analogous protein complexes that control the secretion of bioactive molecules. These complexes include the neuroligins (NLs) and their binding partners, the neurexins (NXs). It has been recently reported that both insulin secretion and the proliferation rates of β-cells increase when cells are co-cultured with full-length NL-2 clusters. The pharmacological use of full-length protein is always problematic due to its unfavorable pharmacokinetic properties. Thus, NL-2-derived short peptide was conjugated to the surface of polyamidoamine-based (PAMAM) dendrimers. This nanoscale composite improved β-cell functions in terms of the rate of proliferation, glucose-stimulated insulin secretion (GSIS), and functional maturation. This functionalized dendrimer also protected β-cells under cellular stress conditions. In addition, various novel peptidomimetic scaffolds of NL-2-derived peptide were designed, synthesized, and conjugated to the surface of PAMAM in order to increase the biostability of the conjugates. However, after being covered by peptidomimetics, PAMAM dendrimers were inactive. Thus, the original peptide-based PAMAM dendrimer is a leading compound for continued research that might provide a unique starting point for designing an innovative class of antidiabetic therapeutics that possess a unique mode of action.

Biofabrication of a vascularized islet organ for type 1 diabetes

Islet transplantation is superior to extrinsic insulin supplementation in the treating severe Type 1 diabetes. However, its efficiency and longevity are limited by substantial islet loss post-transplantation due to lack of engraftment and vascular supply. To overcome these limitations, we developed a novel approach to bio-fabricate functional, vascularized islet organs (VIOs) ex vivo. We endothelialized acellular lung matrixes to provide a biocompatible multicompartment scaffold with an intact hierarchical vascular tree as a backbone for islet engraftment. Over seven days of culture, islets anatomically and functionally integrated into the surrounding bio-engineered vasculature, generating a functional perfusable endocrine organ. When exposed to supra-physiologic arterial glucose levels in vivo and ex vivo, mature VIOs responded with a physiologic insulin release from the vein and provided more efficient reduction of hyperglycemia compared to intraportally transplanted fresh islets. In long-term transplants in diabetic mice, subcutaneously implanted VIOs achieved normoglycemia significantly faster and more efficiently compared to islets that were transplanted in deviceless fashion. We conclude that ex vivo bio-fabrication of VIOs enables islet engraftment and vascularization before transplantation, and thereby helps to overcome limited islet survival and function observed in conventional islet transplantation. Given recent progress in stem cells, this technology may enable assembly of functional personalized endocrine organs.

Induction of functional islet-like cells from human iPS cells by suspension culture

Introduction

To complement islet transplantation for type1 diabetic patients, cell-based therapy using pluripotent stem cells such as ES cells and iPS cells is promising. Many papers have already reported the induction of pancreatic β cells from these cell types, but a suspension culture system has not usually been employed. The aim of this study is to establish a suspension culture method for inducing functional islet-like cells from human iPS cells.

Methods

We used 30 ml spinner type culture vessels for human iPS cells throughout the differentiation process. Differentiated cells were analyzed by immunostaining and C-peptide secretion. Cell transplantation experiments were performed with STZ-induced diabetic NOD/SCID mice. Blood human C-peptide and glucagon levels were measured serially in mice, and grafts were analyzed histologically.

Results

We obtained spherical pancreatic beta-like cells from human iPS cells and detected verifiable amounts of C-peptide secretion in vitro. We demonstrated reversal of hyperglycemia in diabetic model mice after transplantation of these cells, maintaining non-fasting blood glucose levels along with the human glycemic set point. We confirmed the secretion of human insulin and glucagon dependent on the blood glucose level in vivo. Immunohistological analysis revealed that grafted cells became α, β and δ cells in vivo.

Conclusions

These results suggest that differentiated cells derived from human iPS cells grown in suspension culture mature and function like pancreatic islets in vivo.

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Functional islet-like cells were induced from human iPS cells by suspension culture.

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They ameliorated hyperglycemia in diabetic mice and secreted human insulin and glucagon.

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Grafted cells became α, β and δ cells in vivo.

Extending Remission and Reversing New-Onset Type 1 Diabetes by Targeted Ablation of Autoreactive T Cells

Preserving endogenous insulin production is clinically advantageous and remains a vital unmet challenge in the treatment and reversal of type 1 diabetes. Although broad immunosuppression has had limited success in prolonging the so-called remission period, it comes at the cost of compromising beneficial immunity. Here, we used a novel strategy to specifically deplete the activated diabetogenic T cells that drive pathogenesis while preserving not only endogenous insulin production but also protective immunity. Effector T (Teff) cells, such as diabetogenic T cells, are naturally poised on the edge of apoptosis because of activation-induced DNA damage that stresses the p53 regulation of the cell cycle. We have found that using small molecular inhibitors that further potentiate p53 while inhibiting the G2/M cell cycle checkpoint control drives apoptosis of activated T cells in vivo. When delivered at the onset of disease, these inhibitors significantly reduce diabetogenic Teff cells, prolong remission, preserve functional islets, and protect islet allografts while leaving naive, memory, and regulatory T-cell populations functionally untouched. Thus, the targeted manipulation of p53 and cell cycle checkpoints represents a new therapeutic modality for the preservation of islet β-cells in new-onset type 1 diabetes or after islet transplant.

Tackling the Concept of Symbiotic Implantable Medical Devices with Nanobiotechnologies

This review takes an approach to implanted medical devices that considers whether the intention of the implanted device is to have any communication of energy or materials with the body. The first part describes some specific examples of three different classes of implants, analyzed with regards to the type of signal sent to cells. Through several examples, the authors describe that a one way signaling to the body leads to encapsulation or degradation. In most cases, those phenomena do not lead to major problems. However, encapsulation or degradation are critical for new kinds of medical devices capable of duplex communication, which are defined in this review as symbiotic devices. The concept the authors propose is that implanted medical devices that need to be symbiotic with the body also need to be designed with an intended duplex communication of energy and materials with the body. This extends the definition of a biocompatible system to one that requires stable exchange of materials between the implanted device and the body. Having this novel concept in mind will guide research in a new field between medical implant and regenerative medicine to create actual symbiotic devices.

Insulin-mimetic effects of short-term rapamycin in type 1 diabetic patients prior to islet transplantation

BACKGROUND

The immunosuppressive drug rapamycin may influence insulin sensitivity in insulin-responsive tissues.

AIMS

This study aimed at evaluating the effectiveness of rapamycin pre-treatment before pancreatic islet allotransplantation (ITx) in patients with type 1 diabetes mellitus (T1DM).

METHODS

Forty-one T1DM patients were studied. Thirteen patients with poor glycemic control underwent a short-term rapamycin treatment before ITx (Group 1), and they were compared to 28 patients undergoing ITx without rapamycin pre-treatment (Group 2). Outcomes were daily insulin requirement (DIR), fasting blood glucose, HbA1c, C-peptide and the SUITO index of beta-cell function. A subgroup of patients pre-treated with rapamycin before ITx underwent euglycemic hyperinsulinemic clamp with [6,6-²H₂] glucose before and after ITx to evaluate insulin sensitivity.

RESULTS

We found a significant reduction in DIR after rapamycin pre-treatment (- 8 ± 6 U/day, mean ± SD, p < 0.001) and 1 year after ITx. DIR reduction 1 year after ITx was greater in Group 1 as compared to Group 2 (- 37 ± 15 vs. - 19 ± 13 U/day, p = 0.005) and remained significant after adjusting for gender, age, glucose and baseline HbA1c (beta = 18.2 ± 5.9, p = 0.006). Fasting glucose and HbA1c significantly decreased 1 year after ITx in Group 1 (HbA1c: - 2.1 ± 1.4%, p = 0.002), while fasting C-peptide (+0.5 ± 0.3 nmol/l, p = 0.002) and SUITO index increased (+57.4 ± 39.7, p = 0.016), without differences between the two groups. Hepatic glucose production decreased after rapamycin pre-treatment (- 1.1 ± 1.1 mg/kg/min, p = 0.04) and after ITx (- 1.6 ± 0.6 mg/kg/min, p = 0.015), while no changes in peripheral glucose disposal were observed.

CONCLUSIONS

Rapamycin pre-treatment before ITx succeeds in reducing insulin requirement, enhancing hepatic insulin sensitivity. This treatment may improve short-term ITx outcomes, possibly in selected patients with T1DM complicated by insulin resistance.

CLINICAL TRIAL

Clinicaltrials.gov NCT01060605; NCT00014911.

Defining outcomes for beta cell replacement therapy: a work in progress

Defined outcomes for beta cell replacement therapy in the treatment of diabetes are critically needed. Progress towards the clinical acceptance of pancreas and islet transplantation has been hampered by the lack of clear definitions of functional and efficacy outcomes, as well as a lack of consistently applied glycaemic control metrics, together with poor alignment with the field of artificial insulin delivery/artificial pancreas development. To address this problem, the International Pancreas & Islet Transplant Association (IPITA) collaborated with the European Pancreas and Islet Transplant Association (EPITA) to develop a consensus for a joint statement on the definition of function and failure of beta cell replacement therapies, which is summarised in this commentary.

Insights into Islet Differentiation and Maturation through Proteomic Characterization of a Human iPSC-Derived Pancreatic Endocrine Model

PURPOSE

Great progresses have been made for generating in vitro pluripotent stem cell pancreatic β-like cells. However, the maturation stage of the cells still requires in vivo maturation to recreate the environmental niche. A deeper understanding of the factors promoting maturation of the cells is of great interest for clinical applications.

EXPERIMENTAL DESIGN

Label-free mass spectrometry based proteomic analysis is performed on samples from a longitudinal study of differentiation of human induced pluripotent stem cells toward glucose responsive insulin producing cells.

RESULTS

Proteome patterns correlate with specific transcription factor gene expression levels during in vitro differentiation, showing the relevance of the technology for identification of pancreatic-specific markers. The analysis of proteomes of the implanted cells in a longitudinal study shows that the neovascularization process linked to the extracellular matrix environment is time-dependent and conditions the proper maturation of the cells in β-like cells secreting insulin in response to glucose.

CONCLUSIONS AND CLINICAL RELEVANCE

Proteomic profiling is valuable to qualify and better understand in vivo maturation of progenitor cells toward β-cells. This is critical for future clinical trials where in vivo maturation still needs to be improved for robustness and effectiveness of cell therapy. Novel biomarkers for predicting the efficiency of maturation represents noninvasive monitoring tools for following efficiency of the implant.

Effect of γ-Aminobutyric Acid-Chitosan Nanoparticles on Glucose Homeostasis in Mice

Diabetes mellitus is the most common endocrine disease worldwide; hyperglycemia is a hallmark of this disease. To alleviate the pain caused by diabetes, developing and utilizing effective diabetic drugs to maintain or recover the function of the residual β-cells is an attractive therapeutic approach. γ-aminobutyric acid (GABA) has been shown to have such effects, but it is easy to have reduced GABA activity under physiological conditions. In the present study, GABA-chitosan nanoparticles (GABA-CS NPs) were prepared, and glucose homeostasis, pancreatic β-cell protection, and anti-inflammatory effects of GABA-CS NPs were investigated in vivo. The results showed that blood glucose levels and IL-1β levels in the GABA-CS NP-administered group were both significantly lower, whereas the PDX1 expression was significantly higher than that of the impaired group (p < 0.01). This indicates that GABA-CS NPs can efficiently maintain glucose homeostasis, protect β-cells, and inhibit inflammation. These nanoparticles have the potential to be applied for future diabetes theranostics.

Proceedings of the signature series event of the international society for cellular therapy: "Advancements in cellular therapies and regenerative medicine in digestive diseases," London, United Kingdom, May 3, 2017

A summary of the First Signature Series Event, "Advancements in Cellular Therapies and Regenerative Medicine for Digestive Diseases," held on May 3, 2017, in London, United Kingdom, is presented. Twelve speakers from three continents covered major topics in the areas of cellular therapy and regenerative medicine applied to liver and gastrointestinal medicine as well as to diabetes mellitus. Highlights from their presentations, together with an overview of the global impact of digestive diseases and a proposal for a shared online collection and data-monitoring platform tool, are included in this proceedings. Although growing evidence demonstrate the feasibility and safety of exploiting cell-based technologies for the treatment of digestive diseases, regulatory and methodological obstacles will need to be overcome before the successful implementation in the clinic of these novel attractive therapeutic strategies.

Effect of resveratrol treatment on graft revascularization after islet transplantation in streptozotocin-induced diabetic mice

We evaluated the effect of resveratrol (RSV) on graft survival after islet transplantation (ITx) in diabetic mice. Isolated islets from Balb/c mice (200 IEQ) were transplanted under the kidney capsule of diabetic Balb/c mice. Vehicle or RSV (200 mg/kg/day, orally) was given for 14 days after ITx. Two more control groups [STZ-treated (No-ITx-Control) and STZ+RSV-treated (No-ITx-RSV) mice without ITx] were added. Glucose tolerance tests (GTT) was performed at 14 days after ITx. In vitro, isolated islets pretreated with vehicle or RSV (1 μM) were incubated in a hypoxic chamber (O2 1%, 1hr). Some of the ITx was performed in mouse insulin 1 gene promoter-green fluorescent protein (MIP-GFP) transgenic mice and analyzed using an in vivo imaging system. After 14 days of ITx, 2-hr glucose levels on GTT in the RSV-treated group were significantly lower than those of other control groups. But the glucose status was not improved in No-ITx mice with RSV. At day 3, the percentage of Ki-67/insulin co-stained cells in islet graft was significantly increased in the RSV-ITx group. Immunostaining with anti-insulin and anti-BS-1 antibodies revealed significantly higher insulin-stained area and vascular density in RSV-treated islet grafts. The mean vessel volume per islet graft measured by in vivo imaging was significantly higher in the RSV-treated group at day 3. In isolated islets cultured in hypoxic conditions, the cell death rate and oxidative stress were significantly attenuated with RSV pretreatment. Hypoxic treatment for isolated islets decreased the expression of SIRT-1 mRNA, and this attenuation was recovered by RSV pretreatment. Our data suggest that RSV treatment improved glycemic control, beta-cell proliferation, reduced oxidative stress, and enhanced islet revascularization and the outcome of ITx in diabetic mice.

Aldehyde dehydrogenase 1 a1 regulates energy metabolism in adipocytes from different species

BACKGROUND

Survival and longevity of xenotransplants depend on immune function and ability to integrate energy metabolism between cells from different species. However, mechanisms for interspecies cross talk in energy metabolism are not well understood. White adipose tissue stores energy and is capable of mobilization and dissipation of energy as heat (thermogenesis) by adipocytes expressing uncoupling protein 1 (Ucp1). Both pathways are under the control of vitamin A metabolizing enzymes. Deficient retinoic acid production in aldehyde dehydrogenase 1 A1 (Aldh1a1) knockout adipocytes (KO) inhibits adipogenesis and increases thermogenesis. Here we test the role Aldh1a1 in regulation of lipid metabolism in xenocultures.

METHODS

Murine wide-type (WT) and KO pre-adipocytes were encapsulated into a poly-L-lysine polymer that allows exchange of humoral factors <32kD via nanopores. Encapsulated murine adipocytes were co-incubated with primary differentiated canine adipocytes. Then, expression of adipogenic and thermogenic genes in differentiated canine adipocytes was detected by real-time polymerase chain reaction (PCR). The regulatory factors in WT and KO cells were identified by comparison of secretome using proteomics and in transcriptome by gene microarray.

RESULTS

Co-culture of encapsulated mouse KO vs WT adipocytes increased expression of peroxisome proliferator-activated receptor gamma (Pparg), but reduced expression of its target genes fatty acid binding protein 4 (Fabp4), and adipose triglyceride lipase (Atgl) in canine adipocytes, suggesting inhibition of PPARγ activation. Co-culture with KO adipocytes also induced expression of Ucp1 in canine adipocytes compared to expression in WT adipocytes. Cumulatively, murine KO compared to WT adipocytes decreased lipid accumulation in canine adipocytes. Comparative proteomics revealed significantly higher levels of vitamin A carriers, retinol binding protein 4 (RBP4), and lipokalin 2 (LCN2) in KO vs WT adipocytes.

CONCLUSIONS

Our data demonstrate the functional exchange of regulatory factors between adipocytes from different species for regulation of energy balance. RBP4 and LCN2 appear to be involved in the transport of retinoids for regulation of lipid accumulation and thermogenesis in xenocultures. While the rarity of thermogenic adipocytes in humans and dogs precludes their use for autologous transplantation, our study demonstrates that xenotransplantation of engineered cells could be a potential solution for the reduction in obesity in dogs and a strategy for translation to patients.

PTPN22 and islet-specific autoimmunity: What have the mouse models taught us?

An allelic variant of the protein tyrosin phosphatase non-receptor 22 (PTPN22) gene, PTPN22 R620W, constitutes the strongest non-HLA genetic risk factor for the development of type 1 diabetes (T1D). A number of studies using mouse models have addressed how PTPN22 predisposes to T1D. PTPN22 downmodulation, overexpression or expression of the variant gene in genetically manipulated mice has generated controversial results. These discrepancies probably derive from the fact that PTPN22 has differential effects on innate and adaptive immune responses. Moreover, the effects of PTPN22 are dependent on other genetic variables. Here we discuss these findings and try to explain the discrepancies. Exploring the mechanism by which PTPN22 contributes to islet-specific autoimmunity could help us understand its role in T1D pathogenesis and exploit it as a potential therapeutic target to prevent the disease.

Effects of bone marrow on the microenvironment of the human pancreatic islet: A Protein Profile Approach

Stem cells are a new therapeutic modality that may support the viability and function of human organs and tissue. Our previous studies have revealed that human allogeneic bone marrow (BM) sustains pancreatic β cell function and survival. This paper examines whether BM creates a microenvironment that supports human pancreatic islets in vitro by evaluating 107 proteins in culture media from BM, islet, and islet/bone marrow (IB) with mass spectrometry. Proteins were considered up- or down-regulated if p-values < 0.05 and fold change was greater than 2 fold I VS. IB. In addition, proteins identified that were uniquely found in islets co-cultured with bone marrow, but not in islets or bone marrow. A 95% protein probability was used as a threshold. Twenty three proteins were upregulated, and sixteen proteins were downregulated. The function of each protein is listed based on the protein database, which include structural proteins (9 upregulated, 4 downregulated); anti-protease and anti-endopeptidase enzymes (8 upregulated); cation binding proteins (6 up-regulated). Six proteins were uniquely identified in islet co-cultured with bone marrow. Three are anti-proteases or anti-endopeptidases, and 1 is a structural protein. These findings suggest that BM, by changing culture media proteins, may be one of mechanisms to maintain human islet function and survival.

Why should people with type 1 diabetes exercise regularly?

Plethoric evidence reminds of the protective effects of exercise against a number of health risks, across all ages, in the general population. The benefits of exercise for individuals with type 2 diabetes are indisputable. An in-depth understanding of energy metabolism has reasonably entailed exercise as a cornerstone in the lifestyle of almost all subjects with type 1 diabetes. Nevertheless, individuals with type 1 diabetes often fail in accomplishing exercise guidelines and they are less active than their peer without diabetes. Two major obstacles are feared by people with type 1 diabetes who wish to exercise regularly: management of blood glucose control and hypoglycemia. Nowadays, strategies, including glucose monitoring technology and insulin pump therapy, have significantly contributed to the participation in regular physical activity, and even in competitive sports, for people with type 1 diabetes. Novel modalities of training, like different intensity, interspersed exercise, are as well promising. The beneficial potential of exercise in type 1 diabetes is multi-faceted, and it has to be fully exploited because it goes beyond the insulin-mimetic action, possibly through immunomodulation.

MRI tracking of autologous pancreatic progenitor-derived insulin-producing cells in monkeys

Insulin-producing cells (IPCs) derived from a patient’s own stem cells offer great potential for autologous transplantation in diabetic patients. However, the limited survival of engrafted cells remains a bottleneck in the application of this strategy. The present study aimed to investigate whether nanoparticle-based magnetic resonance (MR) tracking can be used to detect the loss of grafted stem cell-derived IPCs in a sensitive and timely manner in a diabetic monkey model. Pancreatic progenitor cells (PPCs) were isolated from diabetic monkeys and labeled with superparamagnetic iron oxide nanoparticles (SPIONs). The SPION-labeled cells presented as hypointense signals on MR imaging (MRI). The labeling procedure did not affect the viability or IPC differentiation of PPCs. Importantly, the total area of the hypointense signal caused by SPION-labeled IPCs on liver MRI decreased before the decline in C-peptide levels after autotransplantation. Histological analysis revealed no detectable immune response to the grafts and many surviving insulin- and Prussian blue-positive cell clusters on liver sections at one year post-transplantation. Collectively, this study demonstrates that SPIO nanoparticles can be used to label stem cells for noninvasive, sensitive, longitudinal monitoring of stem cell-derived IPCs in large animal models using a conventional MR imager.