Developments in stem cell-derived islet replacement therapy for treating type 1 diabetes

An adult clock regulator links circadian rhythms to pancreatic β-cell maturation

The circadian clock attunes metabolism to daily energy cycles, but how it regulates maturation of metabolic tissues is poorly understood. Here we show that DEC1, a clock transcription factor induced in adult islet β cells, coordinates their glucose responsiveness by synchronizing energetic and secretory rhythms. DEC1 binds and regulates maturity-linked genes to integrate insulin exocytosis with energy metabolism, and β-cell Dec1 ablation disrupts their transcription synchrony. Dec1-disrupted mice develop lifelong glucose intolerance and insulin deficiency, despite normal islet formation and intact Clock/Bmal1 genes. Metabolic dysfunction upon β-cell Dec1 loss stems from poor coupling of insulin secretion to glucose metabolism, reminiscent of fetal/neonatal immaturity. We link stunted maturation to a deficit in circadian bioenergetics, prompted by compromised glucose utilization, mitochondrial dynamics, and respiratory metabolism, which is rescued by increased metabolic flux. Thus, DEC1 links circadian clockwork to β-cell metabolic maturation, revealing a hierarchy for how the clock programs metabolic tissue specialization.

A 3D-printed microdevice encapsulates vascularized islets composed of iPSC-derived β-like cells and microvascular fragments for type 1 diabetes treatment

Transplantation of insulin-secreting cells provides a promising method for re-establishing the autonomous blood glucose control ability of type 1 diabetes (T1D) patients, but the low survival of the transplanted cells hinder the therapeutic efficacy. In this study, we 3D-printed an encapsulation system containing β-like cells and microvascular fragments (MVF), to create a retrivable microdevice with vascularized islets in vivo for T1D therapy. The functional β-like cells were differentiated from the urine epithelial cell-derived induced pluripotent stem cells (UiPSCs). Single-cell RNA sequencing provided an integrative study and macroscopic developmental analyses of the entire process of differentiation, which revealed the developmental trajectory of differentiation in vitro follows the developmental pattern of embryonic pancreas in vivo. The MVF were isolated from the epididymal fat pad. The microdevice with a groove structure were rapidly fabricated by the digital light processing (DLP)-3D printing technology. The β-like cells and MVF were uniformly distributed in the device. After subcutaneous transplantation into C57BL/6 mice, the microdevice have less collagen accumulation and low immune cell infiltration. Moreover, the microdevice encapsulated vascularized islets reduced hyperglycemia in 33 % of the treated mice for up to 100 days without immunosuppressants, and the humanized C-peptide was also detected in the serum of the mice. In summary, we described the microdevice-protected vascularized islets for long-term treatment of T1D, with high safety and potential clinical transformative value, and may therefore provide a translatable solution to advance the research progress of β cell replacement therapy for T1D.

Pharmacotherapy of type 1 diabetes - part 3: tomorrow

INTRODUCTION

The last 100 years have seen type 1 diabetes, a previously fatal disease, transformed by the administration of exogenous insulin.

AREAS COVERED

A standard literature search using the Google and Microsoft search engines and PubMed was performed. The development of synthetic insulins with varying onsets and duration of action improved glucose control, essential to mitigate the microvascular and macrovascular consequences of diabetes. Today insulin pumps guided by continuous glucose monitors are approaching the objective of normalized glucose levels. The area of greatest development is now in attempting to suppress the immune process which results in progressive destruction of the beta cell. It is possible to identify family members of patients with type 1 diabetes who may eventually develop the disease by measuring several beta cell antibodies. Very recently teplizumab, a CD3 inhibitor, has been approved to delay the onset of hyperglycemia in these individuals.

EXPERT OPINION

The future will see progress in immunosuppression, possibly using specific CAR-Treg cells directed at the beta cell antigens which trigger the immune process. In parallel, stem cell-derived beta cells may eventually make it possible to replace lost beta cells, resulting in a true cure for type 1 diabetes.

Engineering Gene and Protein Switches for Regulation of Lineage-Specifying Transcription Factors

Human pluripotent stem cells (hPSCs) can be differentiated in vitro to an increasing number of mature cell types, presenting significant promise for addressing a wide range of diseases and studying human development. One approach to further enhance stem cell differentiation methods would be to coordinate multiple inducible gene or protein switches to operate simultaneously within the same cell, with minimal cross-interference, to precisely regulate a network of lineage-specifying transcription factors (TFs) to guide cell fate decisions. Therefore, in this study, we designed and tested various mammalian gene and protein switches responsive to clinically safe small-molecule inhibitors of viral proteases. First, we leveraged hepatitis C virus and human rhinovirus proteases to control the activity of chimeric transcription factors, enabling gene expression activation exclusively in the presence of protease inhibitors and achieving high fold-inductions in hPSC lines. Second, we built single-chain protein switches regulating the activity of three differentiation-related pancreatic TFs, MafA, Pdx1, and Ngn3, each engineered with a protease cleavage site within its structure and having the corresponding protease fused at one terminus. While variants lacking the protease retained most of the unmodified TF activity, the attachment of the protease significantly decreased the activity, which could be rescued upon addition of the corresponding protease inhibitor. We confirmed the functionality of these protein switches for simultaneously controlling the activity of three TFs with a common input molecule, as well as the orthogonality of each protease-based system to independently regulate two TFs. Finally, we validated these very compact systems for precisely controlling TF activity in hPSCs. Our results suggest that they will be valuable tools for research in both developmental biology and regenerative medicine.

Glucose Control in Type 1 Diabetes after Pancreas Transplantation: Does Automated Delivery Offer Comparable Results?

Objectives: Pancreas transplantation provides long-term near-normal glycemic control for recipients with type 1 diabetes, but it is unknown how this control compares with an automated insulin delivery (AID) system. Methods: In this prospective study, we compared parameters from 31 consecutive pancreas-kidney transplantation recipients versus from 377 people using an AID-either MiniMed™ 780G (n = 200) or Tandem t:slim X2™ Control-IQ™ (n = 177). Results: Compared with the MiniMed and Tandem AID groups, transplant recipients at 1 month (mean ± standard deviation [SD]: 36 ± 12 days) after pancreas transplantation exhibited significantly lower glycated hemoglobin (38 mmol/mol [36, 40] vs. 55 [53, 56.5] and 56 [54.7, 57.2], respectively), lower mean glycemia (6.4 mmol/L [6, 6.8] vs. 8.5 [8.3, 8.7] and 8.2 [8.0, 8.4], respectively), and spent more time in range (90% [86, 93] vs. 72% [70, 74] and 75% [73, 77], respectively). Time in hypoglycemia did not differ significantly between the groups. Conclusions: Overall, compared with AID treatment, pancreas transplantation led to significantly better diabetes control parameters, with the exception of time below range. Clinical trials registration number is Eudra CT No. 2019-002240-24.

Multilayered Freestanding Porous Polycarbonate Nanosheets with Directed Protein Permeability for Cell-Encapsulated Devices

Implantable pancreatic β cell-encapsulated devices are required for the treatment of type 1 diabetes. Such devices should enable a semipermeable membrane to release insulin in response to glucose levels while avoiding immune reactions. Micrometer-thick track-etched porous polycarbonate (PC) membranes have been used for this purpose. However, the immediate release of insulin remains a challenge in the development of such semipermeable membranes. Herein, we attempted to develop a freestanding polymeric ultrathin film (nanosheet) with a porous structure that can be used in a cell-encapsulated device. Specifically, we fabricated a nonbiodegradable, porous PC nanosheet to enhance molecular permeability. The nanosheet was multistacked to ensure the controlled permeability of proteins of various molecular weights, such as insulin and IgG. The porous PC nanosheet was prepared by gravure coating using a blend solution comprising PC and polystyrene (PS) to induce macro-phase separation of the PC and PS. When the PC:PS weight ratio of the mixture was reduced to 3:1, we succeeded in fabricating a porous PC nanosheet (thickness: 100 nm, diameter: < 2.5 μm). A triple layer of such porous nanosheets with various pore sizes demonstrated 10 times less protein clogging, 10 times higher insulin permeability, and comparable IgG-blocking capability compared with commercially available porous PC membranes (thickness: 10 μm). Finally, we demonstrated that a cell-encapsulated device equipped with the multilayered porous PC nanosheet as a permeable membrane preserved the glucose response level of insulin-producing cells before, during, and after the cell-encapsulation process. We believe that cell-encapsulated devices equipped with such porous PC nanosheets will enable immediate insulin release in response to changes in glucose levels.

Islet Cell Replacement and Regeneration for Type 1 Diabetes: Current Developments and Future Prospects

Type 1 diabetes (T1D) is a chronic autoimmune disorder characterized by the destruction of insulin-producing beta cells in the pancreas, leading to insulin deficiency and chronic hyperglycemia. The main current therapeutic strategies for clinically overt T1D - primarily exogenous insulin administration combined with blood glucose monitoring - fail to fully mimic physiological insulin regulation, often resulting in suboptimal or insufficient glycemic control. Islet cell transplantation has emerged as a promising avenue for functionally replacing endogenous insulin production and achieving long-term glycemic stability. Here, we provide an overview of current islet replacement strategies, ranging from islet transplantation to stem cell-derived islet cell transplantation, and highlight emerging approaches such as immunoengineering. We examine the advancements in immunosuppressive protocols to enhance graft survival, innovative encapsulation, and immunomodulation techniques to protect transplanted islets, and the ongoing challenges in achieving durable and functional islet integration. Additionally, we discuss the latest clinical outcomes, the potential of gene editing technologies, and the emerging strategies for islet cell regeneration. This review aims to highlight the potential of these approaches to transform the management of T1D and improve the quality of life of individuals affected by this condition.

IL-4-primed human umbilical cord mesenchymal stem cells-derived extracellular vesicles facilitate recovery in spinal cord injury via the miR-21-5p/PDCD4-mediated shifting of macrophage M1/M2 polarization

Spinal cord injury (SCI) represents a significant neurological disorder that profoundly impacts human life. Transplantation of extracellular vesicles (EVs) from human umbilical cord mesenchymal stem cells (hUC-MSCs) has emerged as a promising therapeutic strategy. microRNA (miRNA) containing EVs serve as crucial mediators of intercellular communication, playing vital roles in physiological and pathological processes. Research indicates that EVs from hUC-MSCs could attenuate inflammation and facilitate recovery from SCI. Nevertheless, their application in clinical treatment necessitates further investigation. We are actively pursuing an effective approach to modulate the intensity of the inflammatory response, thereby addressing secondary SCI. Initially, we activated hUC-MSCs with interleukin-4 (IL-4) and subsequently harvested their EVs. We investigated the influences of A-hUC-MSCs-EVs compared to routinely acquired EVs on macrophage polarization phenotypes both in vitro and in vivo. Our results show that EVs originating from A-hUC-MSCs are more effective at promoting macrophage polarization from the M1 phenotype to the M2 phenotype than those derived from hUC-MSCs. Notably, we found that A-hUC-MSCs-derived EVs had a superior impact on motor function recovery in mice with SCI. Importantly, we observed that IL-4 activation significantly upregulated the expression of miR-21-5p within these EVs. More specifically, our data demonstrate that A-hUC-MSCs-EVs depend on miR-21-5p to inhibit the effects of PDCD4 on macrophage polarization. This mechanism regulates inflammatory responses while simultaneously reducing apoptosis. In summary, EVs derived from IL-4 primed hUC-MSCs are enriched with miR-21-5p, which exerts a pivotal influence in shifting macrophage polarization, alleviating inflammatory responses following SCI, and facilitating recovery.

AG73-GelMA/AlgMA hydrogels provide a stable microenvironment for the generation of pancreatic progenitor organoids

Patient specific induced pluripotent stem cells (iPSCs) derived β cells represent an effective means for disease modeling and autologous diabetes cell replacement therapy. In this study, an AG73-5%gelatin methacryloyl (GelMA) /2% alginate methacrylate (AlgMA) hydrogel was employed to generate pancreatic progenitor (PP) organoids and improve stem cell-derived β (SC-β) cell differentiation protocol. The laminin-derived homolog AG73, which mimics certain cell‒matrix interactions, facilitates AKT signaling pathway activation to promote PDX1+/NKX6.1+ PP organoid formation and effectively modulates subsequent epithelial-mesenchymal transition (EMT) in the endocrine lineage. The 5%GelMA/2%AlgMA hydrogel mimics the physiological stiffness of the pancreas, providing the optimal mechanical stress and spatial structure for PP organoid differentiation. The Syndecan-4 (SDC4)-ITGAV complex plays a pivotal role in the early stages of pancreatic development by facilitating the formation of SOX9+/PDX1+ bipotent PPs. Our findings demonstrate that AG73-GelMA/AlgMA hydrogel-derived SC-β cells exhibit enhanced insulin secretion and accelerated hyperglycemia reversal in vivo. This study presents a cost-effective, stable, and efficient alternative for the comprehensive 3D culture of SC-β cells in vitro by mitigating the uncertainties associated with conventional culture methods.

Depolymerizing F-actin accelerates the exit from pluripotency to enhance stem cell-derived islet differentiation

In this study, we demonstrate that cytoskeletal state at the onset of directed differentiation is critical for the specification of human pluripotent stem cells (hPSCs) to all three germ layers. In particular, a polymerized actin cytoskeleton facilitates directed ectoderm differentiation, while depolymerizing F-actin promotes mesendoderm lineages. Applying this concept to a stem cell-derived islet (SC-islet) differentiation protocol, we show that depolymerizing F-actin with latrunculin A (latA) during the first 24 hours of definitive endoderm formation facilitates rapid exit from pluripotency and alters Activin/Nodal, BMP, JNK-JUN, and WNT pathway signaling dynamics. These signaling changes influence downstream patterning of the gut tube, leading to improved pancreatic progenitor identity and decreased expression of markers associated with other endodermal lineages. Continued differentiation generates islets containing a higher percentage of β cells that exhibit improved maturation, insulin secretion, and ability to reverse hyperglycemia. Furthermore, this latA treatment reduces enterochromaffin cells in the final cell population and corrects differentiations from hPSC lines that otherwise fail to consistently produce pancreatic islets, highlighting the importance of cytoskeletal signaling at the onset of directed differentiation.

Cell therapy: A beacon of hope in the battle against pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic and progressive interstitial lung disease characterized by abnormal activation of myofibroblasts and pathological remodeling of the extracellular matrix, with a poor prognosis and limited treatment options. Lung transplantation is currently the only approach that can extend the life expectancy of patients; however, its applicability is severely restricted due to donor shortages and patient-specific limitations. Therefore, the search for novel therapeutic strategies is imperative. In recent years, stem cells have shown great promise in the field of regenerative medicine due to their self-renewal capacity and multidirectional differentiation potential, and a growing body of literature supports the efficacy of stem cell therapy in PF treatment. This paper systematically summarizes the research progress of various stem cell types in the treatment of PF. Furthermore, it discusses the primary methods and clinical outcomes of stem cell therapy in PF, based on both preclinical and clinical data. Finally, the current challenges and key factors to consider in stem cell therapy for PF are objectively analyzed, and future directions for improving this therapy are proposed, providing new insights and references for the clinical treatment of PF patients.

Extracellular matrix proteins refine microenvironments for pancreatic organogenesis from induced pluripotent stem cell differentiation

Rationale: The current understanding on manipulating signaling pathways to generate mature human islet organoids with all major hormone-secreting endocrine cell types (i.e., α, β, δ, and γ cells) from induced pluripotent stem cells (iPSCs) is insufficient. However, donor islet shortage necessitates that we produce functional islets in vitro. In this study, we aimed to find decellularized pancreatic extracellular matrix (dpECM) proteins that leverage signaling pathways and promote functional iPSC islet organogenesis. Methods: We performed proteomic analysis to identify key islet promoting factors from porcine and rat dpECM. With this, we identified collagen type II (COL2) as a potential biomaterial cue that endorses islet development from iPSCs. Using global transcriptome profiling, gene set enrichment analysis, immunofluorescence microscopy, flow cytometry, Western blot, and glucose-stimulated hormonal secretion analysis, we examined COL2's role in regulating iPSC pancreatic lineage specification and signaling pathways, critical to islet organogenesis and morphogenesis. Results: We discovered COL2 acts as a functional biomaterial that augments islet development from iPSCs, similar to collagen type V (COL5) as reported in our earlier study. COL2 substantially stimulates the formation of endocrine progenitors and subsequent islet organoids with significantly elevated expressions of pancreatic signature genes and proteins. Furthermore, it enhances islets' glucose sensitivity for hormonal secretion. A cluster of gene expressions associated with various signaling pathways, including but not limited to oxidative phosphorylation, insulin secretion, cell cycle, the canonical WNT, hypoxia, and interferon-γ response, were considerably affected by COL2 and COL5 cues. Conclusion: We demonstrated dpECM's crucial role in refining stem cell differentiation microenvironments for organoid development and maturation. Our findings on biomaterial-stimulated signaling for stem cell specification, organogenesis, and maturation open up a new way to increase the differentiation efficacy of endocrine tissues that can contribute to the production of biologically functional islets.

Can Islet Transplantation Possibly Reduce Mortality in Type 1 Diabetes

Islet transplantation (IT) is a successful natural cell therapy. But the benefits are known mostly to individuals with severe type 1 diabetes who undergo IT and the health care professionals that work to make the therapy available, reproducible, and safe. Data linking IT to overall survival in T1D might alter this situation and frame the therapy in a more positive light. Recent analysis of mortality in several cohorts suggests that IT has possible survival benefits when used alone or in conjunction with renal transplantation. Multi-center prospective studies with long-term follow-up of individuals that receive stand-alone IT versus individuals who qualify for but do not undergo the procedure would seem reasonable to undertake to confirm an IT survival benefit.

Harnessing cellular therapeutics for type 1 diabetes mellitus: progress, challenges, and the road ahead

Type 1 diabetes mellitus (T1DM) is a growing global health concern that affects approximately 8.5 million individuals worldwide. T1DM is characterized by an autoimmune destruction of pancreatic β cells, leading to a disruption in glucose homeostasis. Therapeutic intervention for T1DM requires a complex regimen of glycaemic monitoring and the administration of exogenous insulin to regulate blood glucose levels. Advances in continuous glucose monitoring and algorithm-driven insulin delivery devices have improved the quality of life of patients. Despite this, mimicking islet function and complex physiological feedback remains challenging. Pancreatic islet transplantation represents a potential functional cure for T1DM but is hindered by donor scarcity, variability in harvested cells, aggressive immunosuppressive regimens and suboptimal clinical outcomes. Current research is directed towards generating alternative cell sources, improving transplantation methods, and enhancing cell survival without chronic immunosuppression. This Review maps the progress in cell replacement therapies for T1DM and outlines the remaining challenges and future directions. We explore the state-of-the-art strategies for generating replenishable β cells, cell delivery technologies and local targeted immune modulation. Finally, we highlight relevant animal models and the regulatory aspects for advancing these technologies towards clinical deployment.

Advancements and Challenges in Immune Protection Strategies for Islet Transplantation

Pancreatic islet transplantation is a crucial treatment for managing type 1 diabetes (T1D) in clinical settings. However, the limited availability of human cadaveric islet donors and the need for ongoing administration of immunosuppressive agents post-transplantation hinder the widespread use of this treatment. Stem cell-derived islet organoids have emerged as an effective alternative to primary human islets. Nevertheless, implementing this cell replacement therapy still requires chronic immune suppression, which may result in life-long side effects. To address these challenges, innovations such as encapsulation devices, universal stem cells, and immunomodulatory strategies are being developed to mitigate immune rejection and prolong the function of the transplant. This review outlines the contemporary challenges in pancreatic β cell therapy, particularly immune rejection, and recent progress in immune-isolation devices, hypoimmunogenic stem cells, and immune regulation of transplants. A comprehensive evaluation of the advantages and limitations of these approaches will contribute to improved future clinical investigations. With these promising advancements, the application of pancreatic β cell therapy holds the potential to effectively treat T1D and benefit a larger population of T1D patients.

The role of fetal pancreatic islet cell transplantation in the treatment of type 2 diabetes mellitus

Objectives

Diabetes mellitus has a negative impact on patients' lives and is a significant medical and social problem. Due to the high prevalence of diabetes mellitus, shortage of donor materials, immune rejection of the pancreas and limited efficacy of existing treatment methods, the study of promising and more effective approaches to the treatment of this disease, such as transplantation of fetal pancreatic islet cells, becomes relevant. The aim of the study is to determine the efficacy and necessity of fetal pancreatic islet cell transplantation in the treatment of type 2 diabetes mellitus.

Methods

The study was carried out with the help of analytical-synthetic method, literature review and analysis of medical databases corresponding to the topic of work, clinical and experimental studies conducted by other authors were considered.

Results

As a result of this work, it was found that the use of fetal stem cell transplantation is an effective method in the treatment of diabetes. Studies confirm that this method reduces hyperglycaemia and NOMA index, increases c-peptide values without serious side effects on the background of treatment.

Conclusions

Fetal islet cells have advantages in cell culture, relatively low immunogenicity, effective engraftment, although they may produce less insulin relative to adult somatic stem cells. Transplanted islet cells are able to replace and renew the function of the recipient's own pancreatic β-cells, and prevent their destruction. Fetal pancreatic islet cell transplantation is a promising treatment option for type 2 diabetes that can complement or replace existing therapies, improving patients' glucose control.

Controlling human stem cell-derived islet composition using magnetic sorting

Stem cell-derived islets (SC-islets) consists of multiple hormone-producing cell types and offer a promising therapeutic avenue for treating type 1 diabetes (T1D). Currently, the composition of cell types generated within these SC-islets currently cannot be controlled via soluble factors during this differentiation process and consist of off-target cell types. In this study, we devised a magnetic-activated cell sorting (MACS) protocol to enrich SC-islets for CD49a, a marker associated with functional insulin-producing β cells. SC-islets were generated from human pluripotent stem cells (hPSCs) using an adherent differentiation protocol and then sorted and aggregated into islet-like clusters to produce CD49a-enriched, CD49a-depleted, and unsorted SC-islets. Single-cell RNA sequencing (scRNA-seq) and immunostaining revealed that CD49a-enriched SC-islets had higher proportions of β cells and improved transcriptional identity compared to other cell types. Functional assays demonstrated that CD49a-enriched SC-islets exhibited enhanced glucose-stimulated insulin secretion both in vitro and in vivo following transplantation into diabetic mice. These findings suggest that CD49a-based sorting significantly improves β cell identity and the overall function of SC-islets, improving their effectiveness for T1D cell replacement therapies.

Investigation of the motif activity of transcription regulators in pancreatic β-like cell subpopulations differentiated from human induced pluripotent stem cells

Pancreatic β-cells are composed of different subtypes that play a key role in the control of insulin secretion and thereby control glucose homeostasis. In vitro differentiation of human induced pluripotent stem cells (hiPSCs) into 3D spheroids leads to the generation of β-cell subtypes and thus to the development of islet-like structures. Using this cutting-edge cell model, the aim of the study was to decipher the signaling signature that underlines β-cell subtypes, with a focus on the search for the activity of motifs of important transcription regulators (TRs). The investigation was performed using data from previous single-cell sequencing analysis introduced into the integrated system for motif activity response analysis (ISMARA) of transcription regulators. We extracted the matrix of important TRs activated in the β-cell subpopulation and bi-hormonal-like β-cells. Based on these TRs and their targets, we built specific regulatory networks for main cell subpopulations. Our data confirmed the transcriptomic heterogeneity of the β-cell subtype lineage and suggested a mechanism that could account for the differentiation of β-cell subtypes during pancreas development. We do believe that our findings could be instrumental for understanding the mechanisms that affect the balance of β-cell subtypes, leading to impaired insulin secretion in type 2 diabetes.

Status of islet transplantation and innovations to sustainable outcomes: novel sites, cell sources, and drug delivery strategies

Islet transplantation (ITx) is an effective means to restore physiologic glycemic regulation in those living with type 1 diabetes; however, there are a handful of barriers that prevent the broad application of this functionally curative procedure. The restricted cell supply, requisite for life-long toxic immunosuppression, and significant immediate and gradual graft attrition limits the procedure to only those living with brittle diabetes. While intraportal ITx is the primary clinical site, portal vein-specific factors including low oxygen tension and the instant blood-mediated inflammatory reaction are detrimental to initial engraftment and long-term function. These factors among others prevent the procedure from granting recipients long-term insulin independence. Herein, we provide an overview of the status and limitations of ITx, and novel innovations that address the shortcomings presented. Despite the marked progress highlighted in the review from as early as the initial islet tissue transplantation in 1893, ongoing efforts to improve the procedure efficacy and success are also explored. Progress in identifying unlimited cell sources, more favourable transplant sites, and novel drug delivery strategies all work to broaden ITx application and reduce adverse outcomes. Exploring combination of these approaches may uncover synergies that can further advance the field of ITx in providing sustainable functional cures. Finally, the potential of biomaterial strategies to facilitate immune evasion and local immune modulation are featured and may underpin successful application in alternative transplant sites.

Immunotherapy in type 1 diabetes: Novel pathway to the future ahead

Since the discovery of insulin over 100 years ago, the focus of research in the management of type 1 diabetes (T1D) has centered around glycemic control and management of complications rather than the prevention of autoimmune destruction of pancreatic β cells. Fortunately, in recent years, there has been significant advancement in immune-targeted pharmacotherapy to halt the natural progression of T1D. The immune-targeted intervention aims to alter the underlying pathogenesis of T1D by targeting different aspects of the immune system. The immunotherapy can either antagonize the immune mediators like T cells, B cells or cytokines (antibody-based therapy), or reinduce self-tolerance to pancreatic β cells (antigen-based therapy) or stem-cell treatment. Recently, the US Food and Drug Administration approved the first immunotherapy teplizumab to be used only in stage 2 of T1D. However, the window of opportunity to practically implement this approved molecule in the selected target population is limited. In this Editorial, we briefly discuss the various promising recent developments in the field of immunotherapy research in T1D. However, further studies of these newer therapeutic agents are needed to explore their true potential for prevention or cure of T1D.

Recent progress in modeling and treating diabetes using stem cell-derived islets

Stem cell-derived islets (SC-islets) offer the potential to be an unlimited source of cells for disease modeling and the treatment of diabetes. SC-islets can be genetically modified, treated with chemical compounds, or differentiated from patient derived stem cells to model diabetes. These models provide insights into disease pathogenesis and vulnerabilities that may be targeted to provide treatment. SC-islets themselves are also being investigated as a cell therapy for diabetes. However, the transplantation process is imperfect; side effects from immunosuppressant use have reduced SC-islet therapeutic potential. Alternative methods to this include encapsulation, use of immunomodulating molecules, and genetic modification of SC-islets. This review covers recent advances using SC-islets to understand different diabetes pathologies and as a cell therapy.

The Role of the Pancreatic Extracellular Matrix as a Tissue Engineering Support for the Bioartificial Pancreas

Type 1 diabetes mellitus (T1DM) is a chronic condition primarily managed with insulin replacement, leading to significant treatment costs. Complications include vasculopathy, cardiovascular diseases, nephropathy, neuropathy, and reticulopathy. Pancreatic islet transplantation is an option but its success does not depend solely on adequate vascularization. The main limitations to clinical islet transplantation are the scarcity of human pancreas, the need for immunosuppression, and the inadequacy of the islet isolation process. Despite extensive research, T1DM remains a major global health issue. In 2015, diabetes affected approximately 415 million people, with projected expenditures of USD 1.7 trillion by 2030. Pancreas transplantation faces challenges due to limited organ availability and complex vascularization. T1DM is caused by the autoimmune destruction of insulin-producing pancreatic cells. Advances in biomaterials, particularly the extracellular matrix (ECM), show promise in tissue reconstruction and transplantation, offering structural and regulatory functions critical for cell migration, differentiation, and adhesion. Tissue engineering aims to create bioartificial pancreases integrating insulin-producing cells and suitable frameworks. This involves decellularization and recellularization techniques to develop biological scaffolds. The challenges include replicating the pancreas's intricate architecture and maintaining cell viability and functionality. Emerging technologies, such as 3D printing and advanced biomaterials, have shown potential in constructing bioartificial organs. ECM components, including collagens and glycoproteins, play essential roles in cell adhesion, migration, and differentiation. Clinical applications focus on developing functional scaffolds for transplantation, with ongoing research addressing immunological responses and long-term efficacy. Pancreatic bioengineering represents a promising avenue for T1DM treatment, requiring further research to ensure successful implementation.

Cryopreservation of Stem Cell-Derived β-Like Cells Enriches for Insulin-Producing Cells With Improved Function

The generation of stem cell-derived β-like cells (sBCs) holds promise as not only an abundant insulin-producing cell source for replacement therapy of type 1 diabetes (T1D) but also as an invaluable model system for investigating human β-cell development, immunogenicity, and function. Several groups have developed methodology to direct differentiate human pluripotent stem cells into pancreatic cell populations that include glucose-responsive sBCs. Nevertheless, the process of generating sBCs poses substantial experimental challenges. It involves lengthy differentiation periods, there is substantial variability in efficiency, and there are inconsistencies in obtaining functional sBCs. Here, we describe a simple and effective cryopreservation approach for sBC cultures that yields homogeneous sBC clusters that are enriched for insulin-expressing cells while simultaneously depleting proliferative progenitors. Thawed sBCs have enhanced glucose-stimulated insulin release compared with controls in vitro and can effectively engraft and function in vivo. Collectively, this approach alleviates current challenges with inefficient and variable sBC generation while improving their functional state. We anticipate that these findings can inform ongoing clinical application of sBCs for the treatment of patients with T1D and serve as an important resource for the wider diabetes field that will allow for accelerated research discoveries.

ARTICLE HIGHLIGHTS

Research advances in understanding crosstalk between organs and pancreatic β-cell dysfunction

Obesity has increased dramatically worldwide. Being overweight or obese can lead to various conditions, including dyslipidaemia, hypertension, glucose intolerance and metabolic syndrome (MetS), which may further lead to type 2 diabetes mellitus (T2DM). Previous studies have identified a link between β-cell dysfunction and the severity of MetS, with multiple organs and tissues affected. Identifying the associations between pancreatic β-cell dysfunction and organs is critical. Research has focused on the interaction between the liver, gut and pancreatic β-cells. However, the mechanisms and related core targets are still not perfectly elucidated. The aims of this review were to summarize the mechanisms of β-cell dysfunction and to explore the potential pathogenic pathways and targets that connect the liver, gut, adipose tissue, muscle, and brain to pancreatic β-cell dysfunction.

Enhancing human islet xenotransplant survival and function in diabetic immunocompetent mice through LRH-1/NR5A2 pharmacological activation

The intricate etiology of type 1 diabetes mellitus (T1D), characterized by harmful interactions between the immune system and insulin-producing beta cells, has hindered the development of effective therapies including human islet transplantation, which requires strong immunosuppressants that impair beta cell survival and function. As such alternative immunomodulating therapies are required for successful transplantation. The discovery that pharmacological activation of the nuclear receptor LRH-1/NR5A2 can reverse hyperglycemia in mouse models of T1D by altering, and not suppressing the autoimmune attack, prompted us to investigate whether LRH-1/NR5A2 activation could improve human islet function/survival after xenotransplantation in immunocompetent mice. Human islets were transplanted under the kidney capsule of streptozotocin (STZ)-induced diabetic mice, and treatment with BL001 (LRH-1/NR5A2 agonist) or vehicle was administered one week post-transplant. Our study, encompassing 3 independent experiments with 3 different islet donors, revealed that mice treated for 8 weeks with BL001 exhibited lower blood glucose levels correlating with improved mouse survival rates as compared to vehicle-treated controls. Human C-peptide was detectable in BL001-treated mice at both 4 and 8 weeks indicating functional islet beta cells. Accordingly, in mice treated with BL001 for 8 weeks, the beta cell mass was preserved, while a significant decrease in alpha cells was observed compared to mice treated with BL001 for only 4 weeks. In contrast, vehicle-treated mice exhibited a reduction in insulin-expressing cells at 8 weeks compared to those at 4 weeks. These results suggest that BL001 significantly enhances the survival, engraftment, and functionality of human islets in a STZ-induced diabetic mouse model.

Non-invasive quantification of stem cell-derived islet graft size and composition

AIMS/HYPOTHESIS

Stem cell-derived islets (SC-islets) are being used as cell replacement therapy for insulin-dependent diabetes. Non-invasive long-term monitoring methods for SC-islet grafts, which are needed to detect misguided differentiation in vivo and to optimise their therapeutic effectiveness, are lacking. Positron emission tomography (PET) has been used to monitor transplanted primary islets. We therefore aimed to apply PET as a non-invasive monitoring method for SC-islet grafts.

METHODS

We implanted different doses of human SC-islets, SC-islets derived using an older protocol or a state-of-the-art protocol and SC-islets genetically rendered hyper- or hypoactive into mouse calf muscle to yield different kinds of grafts. We followed the grafts with PET using two tracers, glucagon-like peptide 1 receptor-binding [18F]F-dibenzocyclooctyne-exendin-4 ([18F]exendin) and the dopamine precursor 6-[18F]fluoro-L-3,4-dihydroxyphenylalanine ([18F]FDOPA), for 5 months, followed by histological assessment of graft size and composition. Additionally, we implanted a kidney subcapsular cohort with different SC-islet doses to assess the connection between C-peptide and stem cell-derived beta cell (SC-beta cell) mass.

RESULTS

Small but pure and large but impure grafts were derived from SC-islets. PET imaging allowed detection of SC-islet grafts even <1 mm3 in size, [18F]exendin having a better detection rate than [18F]FDOPA (69% vs 44%, <1 mm3; 96% vs 85%, >1 mm3). Graft volume quantified with [18F]exendin (r2=0.91) and [18F]FDOPA (r2=0.86) strongly correlated with actual graft volume. [18F]exendin PET delineated large cystic structures and its uptake correlated with graft SC-beta cell proportion (r2=0.68). The performance of neither tracer was affected by SC-islet graft hyper- or hypoactivity. C-peptide measurements under fasted or glucose-stimulated conditions did not correlate with SC-islet graft volume or SC-beta cell mass, with C-peptide under hypoglycaemia having a weak correlation with SC-beta cell mass (r2=0.52).

CONCLUSIONS/INTERPRETATION

[18F]exendin and [18F]FDOPA PET enable non-invasive assessment of SC-islet graft size and aspects of graft composition. These methods could be leveraged for optimising SC-islet cell replacement therapy in diabetes.

Engineered IRES-mediated promoter-free insulin-producing cells reverse hyperglycemia

Background

Endogenous insulin supplementation is essential for individuals with type 1 diabetes (T1D). However, current treatments, including pancreas transplantation, insulin injections, and oral medications, have significant limitations. The development of engineered cells that can secrete endogenous insulin offers a promising new therapeutic strategy for type 1 diabetes (T1D). This approach could potentially circumvent autoimmune responses associated with the transplantation of differentiated β-cells or systemic delivery of viral vectors.

Methods

We utilized CRISPR/Cas9 gene editing coupled with homology-directed repair (HDR) to precisely integrate a promoter-free EMCVIRES-insulin cassette into the 3' untranslated region (UTR) of the GAPDH gene in human HEK-293T cells. Subsequently quantified insulin expression levels in these engineered cells, the viability and functionality of the engineered cells when seeded on different cell vectors (GelMA and Cytopore I) were also assessed. Finally, we investigated the therapeutic potential of EMCVIRES-based insulin secretion circuits in reversing Hyperglycaemia in T1D mice.

Result

Our results demonstrate that HDR-mediated gene editing successfully integrated the IRES-insulin loop into the genome of HEK-293T cells, a non-endocrine cell line, enabling the expression of human-derived insulin. Furthermore, Cytopore I microcarriers facilitated cell attachment and proliferation during in vitro culture and enhanced cell survival post-transplantation. Transplantation of these cell-laden microcarriers into mice led to the development of a stable, fat-encapsulated structure. This structure exhibited the expression of the platelet-endothelial cell adhesion molecule CD31, and no significant immune rejection was observed throughout the experiment. Diabetic mice that received the cell carriers reversed hyperglycemia, and blood glucose fluctuations under simulated feeding stimuli were very similar to those of healthy mice.

Conclusion

In summary, our study demonstrates that Cytopore I microcarriers are biocompatible and promote long-term cell survival in vivo. The promoter-free EMCVIRES-insulin loop enables non-endocrine cells to secrete mature insulin, leading to a rapid reduction in glucose levels. We have presented a novel promoter-free genetic engineering strategy for insulin secretion and proposed an efficient cell transplantation method. Our findings suggest the potential to expand the range of cell sources available for the treatment of diabetes, offering new avenues for therapeutic interventions.

Low Immunogenicity of Keratinocytes Derived from Human Embryonic Stem Cells

Epidermal transplantation is a common and widely used surgical technique in clinical medicine. Derivatives of embryonic stem cells have the potential to serve as a source of transplantable cells. However, allograft rejection is one of the main challenges. To investigate the immunogenicity of keratinocytes derived from human embryonic stem cells (ESKCs), we conducted a series of in vivo and in vitro experiments. The results showed that ESKCs have low HLA molecule expression, limited antigen presentation capabilities, and a weak ability to stimulate the proliferation and secretion of inflammatory factors in allogeneic PBMCs in vitro. In humanized immune mouse models, ESKCs elicited weak transplant rejection responses in the host. Overall, we found that ESKCs have low immunogenicity and may have potential applications in the field of regenerative medicine.

Mesenchymal stem cell conditioned medium improves hypoxic injury to protect islet graft function

OBJECTIVES

Islet transplantation is one of the most promising curative methods for type 1 diabetes mellitus (T1DM), but early hypoxic death of the graft post-transplantation impedes successful treatment. To improve the efficacy of islet transplantation and enhance islet cell resistance to hypoxia, reducing hypoxic injury before revascularization is crucial. Mesenchymal stem cells (MSCs) are known to regulate immune responses and protect against hypoxic damage through paracrine mechanisms. This study aims to verify the protective effects of MSC-conditioned medium (CM) in enhancing islet cells' tolerance to hypoxic conditions and preserving islet graft function.

METHODS

MIN6 cells were cultured under hypoxic conditions (1% oxygen), and their viability was assessed at different time points using AO/PI staining, observed through fluorescence microscopy. MIN6 cells were treated with varying concentrations of MSC-CM under normal and hypoxic conditions. At different time points, cell viability was measured by Annexin/PI flow cytometry, and insulin secretion capacity was assessed through glucose-stimulated insulin secretion tests. A NCG T1DM mouse model was established, and islet cells from BALB/c mice were co-incubated with MSC-CM for 24 hours. The islet cells were then transplanted under the renal capsule of NCG T1DM mice. Mice body weight and blood glucose levels were monitored, and glucose tolerance tests were conducted to evaluate graft function. Graft survival was further assessed by HE staining and insulin immunohistochemistry.

RESULTS

Under hypoxic conditions, MIN6 cell death increased with prolonged hypoxia. Flow cytometry showed that after 48 hours of hypoxia, the survival rate of MIN6 cells was significantly lower than that of the normoxic group [(68.07±7.90)% vs (94.57±2.12)%, P<0.01)]. MSC-CM treatment restored the insulin secretion function of MIN6 cells under hypoxia, with the stimulation index (SI) increasing from 1.43±0.06 to 1.77±0.02 (P<0.001). Both 10% and 20% MSC-CM effectively mitigated hypoxic damage, whereas 30% MSC-CM had weaker effects. Glucose-stimulated insulin secretion results showed trends consistent with cell survival. Primary mouse islet cells pretreated with 10% MSC-CM and transplanted under the renal capsule of T1DM mice showed a sustained decrease in blood glucose levels 5 days post-surgery. HE staining and insulin immunohistochemistry indicated that the islet cells in the MSC-CM group maintained more intact morphology and higher insulin secretion. Glucose tolerance tests demonstrated better graft function in the MSC-CM group.

CONCLUSIONS

Hypoxia significantly reduces the survival of MIN6 cells and suppresses their insulin secretion function. However, MSC-CM can significantly improve hypoxia-induced cell death and functional decline, and protect islet graft function in a T1DM mouse transplantation model.

Human umbilical cord-derived mesenchymal stem cells alleviate valproate-induced immune stress and social deficiency in rats

Introduction

Autism spectrum disorders (ASD) are a set of heterogeneous neurodevelopmental disorders characterized by impaired social interactions and stereotypic behaviors. Current clinical care is palliative at the most and there remains huge unmet medical need to fully address the core symptoms of ASD. Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are emerging as a promising candidate for ASD treatment, but the precise mechanism remains controversial.

Methods

In vitro studies we performed the transwell migration assay to explore the interaction between hUC-MSCs and the primary-cultured cortical neurons. Then we determined the therapeutic effects of intravenous administration of hUC-MSCs in rats challenged with valproic acid (VPA) during gestation, a well-defined rat model of autism.

Results

Our studies showed that hUC-MSCs promoted the growth of primary-cultured cortical neurons. Furthermore, our results demonstrated that hUC-MSCs significantly alleviated microglial activation in the brain, especially in the anterior cingulate cortex, and effectively improved the sociability of the VPA-exposed rats.

Discussion

These results offer valuable insights for clinical translation and further research on the mechanisms of hUC-MSCs in psychiatric disorders characterized by microglial activation, particularly in cases of autism, shall be warranted.

Immunoprotection Strategies in β-Cell Replacement Therapy: A Closer Look at Porcine Islet Xenotransplantation

Type 1 diabetes mellitus (T1DM) is characterized by absolute insulin deficiency primarily due to autoimmune destruction of pancreatic β-cells. The prevailing treatment for T1DM involves daily subcutaneous insulin injections, but a substantial proportion of patients face challenges such as severe hypoglycemic episodes and poorly controlled hyperglycemia. For T1DM patients, a more effective therapeutic option involves the replacement of β-cells through allogeneic transplantation of either the entire pancreas or isolated pancreatic islets. Unfortunately, the scarcity of transplantable human organs has led to a growing list of patients waiting for an islet transplant. One potential alternative is xenotransplantation of porcine pancreatic islets. However, due to inter-species molecular incompatibilities, porcine tissues trigger a robust immune response in humans, leading to xenograft rejection. Several promising strategies aim to overcome this challenge and enhance the long-term survival and functionality of xenogeneic islet grafts. These strategies include the use of islets derived from genetically modified pigs, immunoisolation of islets by encapsulation in biocompatible materials, and the creation of an immunomodulatory microenvironment by co-transplanting islets with accessory cells or utilizing immunomodulatory biomaterials. This review concentrates on delineating the primary obstacles in islet xenotransplantation and elucidates the fundamental principles and recent breakthroughs aimed at addressing these challenges.

Pancreatic stellate cells support human pancreatic β-cell viability in vitro and enhance survival of immunoisolated human islets exposed to cytokines

Pancreatic islet transplantation is proposed as a cure for type 1 diabetes mellitus (T1D). Despite its success in optimal regulation of glucose levels, limitations in longevity of islet grafts still require innovative solutions. Inflammatory stress post-transplantation and loss of extracellular matrix attribute to the limited β-cell survival. Pancreatic stellate cells (PSCs), identified as pancreatic-specific stromal cells, have the potential to play a crucial role in preserving islet survival. Our study aimed to determine the effects of PSCs co-cultured with human CM β-cells and human islets under inflammatory stress induced by a cytokine cocktail of IFN-γ, TNF-α and IL-1β. Transwell culture inserts were utilized to assess the paracrine impact of PSCs on β-cells, alongside co-cultures enabling direct interaction between PSCs and human islets. We found that co-culturing PSCs with human CM β-cells and human cadaveric islets had rescuing effects on cytokine-induced stress. Effects were different under normoglycemic and hyperglycemic conditions. PSCs were associated with upregulation of β-cell mitochondrial activity and suppression of inflammatory gene expression. The rescuing effects exist both in indirect and direct co-culture methods. Furthermore, we tested whether PSCs have rescuing effects on human islets in conventional alginate-based microcapsules and in composite microcapsules composed of alginate-pectin collagen type IV, laminin sequence RGD, Nec-1, and amino acid. PSCs partially prevented cytokine-induced stress in both systems, but beneficial effects were stronger in composite capsules. Our findings show novel effects of PSCs on islet health. Islets and PSCs coculturing or co-transplantation might mitigate the inflammation stress and improve islet transplantation outcomes.

Increase in the Expression of Glucose Transporter 2 (GLUT2) on the Peripheral Blood Insulin-Producing Cells (PB-IPC) in Type 1 Diabetic Patients after Receiving Stem Cell Educator Therapy

Multicenter international clinical trials demonstrated the clinical safety and efficacy by using stem cell educator therapy to treat type 1 diabetes (T1D) and other autoimmune diseases. Previous studies characterized the peripheral blood insulin-producing cells (PB-IPC) from healthy donors with high potential to give rise to insulin-producing cells. PB-IPC displayed the molecular marker glucose transporter 2 (GLUT2), contributing to the glucose transport and sensing. To improve the clinical efficacy of stem cell educator therapy in the restoration of islet β-cell function, we explored the GLUT2 expression on PB-IPC in recent onset and longstanding T1D patients. In the Food and Drug Administration (FDA)-approved phase 2 clinical studies, patients received one treatment with the stem cell educator therapy. Peripheral blood mononuclear cells (PBMC) were isolated for flow cytometry analysis of PB-IPC and other immune markers before and after the treatment with stem cell educator therapy. Flow cytometry revealed that both recent onset and longstanding T1D patients displayed very low levels of GLUT2 on PB-IPC. After the treatment with stem cell educator therapy, the percentages of GLUT2+CD45RO+ PB-IPC were markedly increased in these T1D subjects. Notably, we found that T1D patients shared common clinical features with patients with other autoimmune and inflammation-associated diseases, such as displaying low or no expression of GLUT2 on PB-IPC at baseline and exhibiting a high profile of the inflammatory cytokine interleukin (IL)-1β. Flow cytometry demonstrated that their GLUT2 expressions on PB-IPC were also markedly upregulated, and the levels of IL-1β-positive cells were significantly downregulated after the treatment with stem cell educator therapy. Stem cell educator therapy could upregulate the GLUT2 expression on PB-IPC and restore their function in T1D patients, leading to the improvement of clinical outcomes. The clinical data advances current understanding about the molecular mechanisms underlying the stem cell educator therapy, which can be expanded to treat patients with other autoimmune and inflammation-associated diseases.

An Autoclavable and Transparent Thermal Cutter for Reliably Sealing Wet Nanofibrous Membranes

Sealing wet porous membranes is a major challenge when fabricating cell encapsulation devices. Herein, we report the development of an Autoclavable Transparent Thermal Cutter (ATTC) for reliably sealing wet nanofibrous membranes. Notably, the ATTC is autoclavable and transparent, thus enabling in situ visualization of the sealing process in a sterile environment and ensuring an appropriate seal. In addition, the ATTC could generate smooth, arbitrary-shaped sealing ends with excellent mechanical properties when sealing PA6, PVDF, and TPU nanofibrous tubes and PP microporous membranes. Importantly, the ATTC could reliably seal wet nanofibrous tubes, which can shoulder a burst pressure up to 313.2 ± 19.3 kPa without bursting at the sealing ends. Furthermore, the ATTC sealing process is highly compatible with the fabrication of cell encapsulation devices, as verified by viability, proliferation, cell escape, and cell function tests. We believe that the ATTC could be used to reliably seal cell encapsulation devices with minimal side effects.

Hydrogel-Encapsulated Pancreatic Islet Cells as a Promising Strategy for Diabetic Cell Therapy

Islet transplantation has now become a promising treatment for insulin-deficient diabetes mellitus. Compared to traditional diabetes treatments, cell therapy can restore endogenous insulin supplementation, but its large-scale clinical application is impeded by donor shortages, immune rejection, and unsuitable transplantation sites. To overcome these challenges, an increasing number of studies have attempted to transplant hydrogel-encapsulated islet cells to treat diabetes. This review mainly focuses on the strategy of hydrogel-encapsulated pancreatic islet cells for diabetic cell therapy, including different cell sources encapsulated in hydrogels, encapsulation methods, hydrogel types, and a series of accessorial manners to improve transplantation outcomes. In addition, the formation and application challenges as well as prospects are also presented.

Identification of unique cell type responses in pancreatic islets to stress

Diabetes involves the death or dysfunction of pancreatic β-cells. Analysis of bulk sequencing from human samples and studies using in vitro and in vivo models suggest that endoplasmic reticulum and inflammatory signaling play an important role in diabetes progression. To better characterize cell type-specific stress response, we perform multiplexed single-cell RNA sequencing to define the transcriptional signature of primary human islet cells exposed to endoplasmic reticulum and inflammatory stress. Through comprehensive pair-wise analysis of stress responses across pancreatic endocrine and exocrine cell types, we define changes in gene expression for each cell type under different diabetes-associated stressors. We find that β-, α-, and ductal cells have the greatest transcriptional response. We utilize stem cell-derived islets to study islet health through the candidate gene CIB1, which was upregulated under stress in primary human islets. Our findings provide insights into cell type-specific responses to diabetes-associated stress and establish a resource to identify targets for diabetes therapeutics.

Insights into the role of mesenchymal stem cells in cutaneous medical aesthetics: from basics to clinics

With the development of the economy and the increasing prevalence of skin problems, cutaneous medical aesthetics are gaining more and more attention. Skin disorders like poor wound healing, aging, and pigmentation have an impact not only on appearance but also on patients with physical and psychological issues, and even impose a significant financial burden on families and society. However, due to the complexities of its occurrence, present treatment options cannot produce optimal outcomes, indicating a dire need for new and effective treatments. Mesenchymal stem cells (MSCs) and their secretomics treatment is a new regenerative medicine therapy that promotes and regulates endogenous stem cell populations and/or replenishes cell pools to achieve tissue homeostasis and regeneration. It has demonstrated remarkable advantages in several skin-related in vivo and in vitro investigations, aiding in the improvement of skin conditions and the promotion of skin aesthetics. As a result, this review gives a complete description of recent scientific breakthroughs in MSCs for skin aesthetics and the limitations of their clinical applications, aiming to provide new ideas for future research and clinical transformation.

Cell identity dynamics and insight into insulin secretagogues when employing stem cell-derived islets for disease modeling

Stem cell-derived islets (SC-islets) are not only an unlimited source for cell-based therapy of type 1 diabetes but have also emerged as an attractive material for modeling diabetes and conducting screening for treatment options. Prior to SC-islets becoming the established standard for disease modeling and drug development, it is essential to understand their response to various nutrient sources in vitro. This study demonstrates an enhanced efficiency of pancreatic endocrine cell differentiation through the incorporation of WNT signaling inhibition following the definitive endoderm stage. We have identified a tri-hormonal cell population within SC-islets, which undergoes reduction concurrent with the emergence of elevated numbers of glucagon-positive cells during extended in vitro culture. Over a 6-week period of in vitro culture, the SC-islets consistently demonstrated robust insulin secretion in response to glucose stimulation. Moreover, they manifested diverse reactivity patterns when exposed to distinct nutrient sources and exhibited deviant glycolytic metabolic characteristics in comparison to human primary islets. Although the SC-islets demonstrated an aberrant glucose metabolism trafficking, the evaluation of a potential antidiabetic drug, pyruvate kinase agonist known as TEPP46, significantly improved in vitro insulin secretion of SC-islets. Overall, this study provided cell identity dynamics investigation of SC-islets during prolonged culturing in vitro, and insights into insulin secretagogues. Associated advantages and limitations were discussed when employing SC-islets for disease modeling.

Emerging approaches for the development of artificial islets

The islet of Langerhans, functioning as a "mini organ", plays a vital role in regulating endocrine activities due to its intricate structure. Dysfunction in these islets is closely associated with the development of diabetes mellitus (DM). To offer valuable insights for DM research and treatment, various approaches have been proposed to create artificial islets or islet organoids with high similarity to natural islets, under the collaborative effort of biologists, clinical physicians, and biomedical engineers. This review investigates the design and fabrication of artificial islets considering both biological and tissue engineering aspects. It begins by examining the natural structures and functions of native islets and proceeds to analyze the protocols for generating islets from stem cells. The review also outlines various techniques used in crafting artificial islets, with a specific focus on hydrogel-based ones. Additionally, it provides a concise overview of the materials and devices employed in the clinical applications of artificial islets. Throughout, the primary goal is to develop artificial islets, thereby bridging the realms of developmental biology, clinical medicine, and tissue engineering.

Exploring therapy transport from implantable medical devices using experimentally informed computational methods

Implantable medical devices that can facilitate therapy transport to localized sites are being developed for a number of diverse applications, including the treatment of diseases such as diabetes and cancer, and tissue regeneration after myocardial infraction. These implants can take the form of an encapsulation device which encases therapy in the form of drugs, proteins, cells, and bioactive agents, in semi-permeable membranes. Such implants have shown some success but the nature of these devices pose a barrier to the diffusion of vital factors, which is further exacerbated upon implantation due to the foreign body response (FBR). The FBR results in the formation of a dense hypo-permeable fibrous capsule around devices and is a leading cause of failure in many implantable technologies. One potential method for overcoming this diffusion barrier and enhancing therapy transport from the device is to incorporate local fluid flow. In this work, we used experimentally informed inputs to characterize the change in the fibrous capsule over time and quantified how this impacts therapy release from a device using computational methods. Insulin was used as a representative therapy as encapsulation devices for Type 1 diabetes are among the most-well characterised. We then explored how local fluid flow may be used to counteract these diffusion barriers, as well as how a more practical pulsatile flow regimen could be implemented to achieve similar results to continuous fluid flow. The generated model is a versatile tool toward informing future device design through its ability to capture the expected decrease in insulin release over time resulting from the FBR and investigate potential methods to overcome these effects.

GLP-1 Analogue-Loaded Glucose-Responsive Nanoparticles as Allies of Stem Cell Therapies for the Treatment of Type I Diabetes

Type 1 diabetes (T1D) is characterized by insufficient insulin secretion due to β-cell loss. Despite exogenous insulin administration being a lifesaving treatment, many patients still experience severe glycemic lability. For these patients, a β-cell replacement strategy through pancreas or pancreatic islet transplantation is the most physiological approach. However, donors' scarcity and the need for lifelong immunosuppressive therapy pose some challenges. This study proposes an innovative biomimetic pancreas, comprising β- and α-cells differentiated from human induced pluripotent stem cells (hiPSCs) embedded in a biofunctional matrix with glucose-responsive nanoparticles (NPs) encapsulating a glucagon-like peptide 1 (GLP-1) analogue, which aims to enhance the glucose responsiveness of differentiated β-cells. Herein, glucose-sensitive pH-responsive NPs encapsulating exenatide or semaglutide showed an average size of 145 nm, with 40% association efficiency for exenatide-loaded NPs and 55% for semaglutide-loaded NPs. Both peptides maintained their secondary structure after in vitro release and showed a similar effect on INS-1E cells' insulin secretion. hiPSCs were differentiated into β- and α-cells, and insulin-positive cells were obtained (82%), despite low glucose responsiveness, as well as glucagon-positive cells (17.5%). The transplantation of the developed system in diabetic mice showed promising outcomes since there was an increase in the survival rate of those animals. Moreover, diabetic mice transplanted with cells and exenatide showed a decrease in their glucose levels. Overall, the biomimetic pancreas developed in this work showed improvements in diabetic mice survival rate, paving the way for new cellular therapies for T1D that explore the synergy of nanomedicines and stem cell-based approaches.

Advances and challenges of the cell-based therapies among diabetic patients

Diabetes mellitus is a significant global public health challenge, with a rising prevalence and associated morbidity and mortality. Cell therapy has evolved over time and holds great potential in diabetes treatment. In the present review, we discussed the recent progresses in cell-based therapies for diabetes that provides an overview of islet and stem cell transplantation technologies used in clinical settings, highlighting their strengths and limitations. We also discussed immunomodulatory strategies employed in cell therapies. Therefore, this review highlights key progresses that pave the way to design transformative treatments to improve the life quality among diabetic patients.

Diabetes: a review of its pathophysiology, and advanced methods of mitigation

Diabetes mellitus (DM) is a long-lasting metabolic non-communicable disease often characterized by an increase in the level of glucose in the blood or hyperglycemia. Approximately, 415 million people between the ages of 20 and 79 years had DM in 2015 and this figure will rise by 200 million by 2040. In a study conducted by CARRS, it's been found that in Delhi the prevalence of diabetes is around 27% and for prediabetic cases, it is more than 46%. The disease DM can be both short-term and long-term and is often associated with one or more diseases like cardiovascular disease, liver disorder, or kidney malfunction. Early identification of diabetes may help avoid catastrophic repercussions because untreated DM can result in serious complications. Diabetes' primary symptoms are persistently high blood glucose levels, frequent urination, increased thirst, and increased hunger. Therefore, DM is classified into four major categories, namely, Type 1, Type 2, Gestational diabetes, and secondary diabetes. There are various oral and injectable formulations available in the market like insulin, biguanides, sulphonylureas, etc. for the treatment of DM. Recent attention can be given to the various nano approaches undertaken for the treatment, diagnosis, and management of diabetes mellitus. Various nanoparticles like Gold Nanoparticles, carbon nanomaterials, and metallic nanoparticles are some of the approaches mentioned in this review. Besides nanotechnology, artificial intelligence (AI) has also found its application in diabetes care. AI can be used for screening the disease, helping in decision-making, predictive population-level risk stratification, and patient self-management tools. Early detection and diagnosis of diabetes also help the patient avoid expensive treatments later in their life with the help of IoT (internet of medical things) and machine learning models. These tools will help healthcare physicians to predict the disease early. Therefore, the Nano drug delivery system along with AI tools holds a very bright future in diabetes care.

Exosomes derived from mesenchymal stem cells in diabetes and diabetic complications

Diabetes, a group of metabolic disorders, constitutes an important global health problem. Diabetes and its complications place a heavy financial strain on both patients and the global healthcare establishment. The lack of effective treatments contributes to this pessimistic situation and negative outlook. Exosomes released from mesenchymal stromal cells (MSCs) have emerged as the most likely new breakthrough and advancement in treating of diabetes and diabetes-associated complication due to its capacity of intercellular communication, modulating the local microenvironment, and regulating cellular processes. In the present review, we briefly outlined the properties of MSCs-derived exosomes, provided a thorough summary of their biological functions and potential uses in diabetes and its related complications.

Innovations in bio-engineering and cell-based approaches to address immunological challenges in islet transplantation

Human allogeneic pancreatic islet transplantation is a life-changing treatment for patients with severe Type 1 Diabetes (T1D) who suffer from hypoglycemia unawareness and high risk of severe hypoglycemia. However, intensive immunosuppression is required to prevent immune rejection of the graft, that may in turn lead to undesirable side effects such as toxicity to the islet cells, kidney toxicity, occurrence of opportunistic infections, and malignancies. The shortage of cadaveric human islet donors further limits islet transplantation as a treatment option for widespread adoption. Alternatively, porcine islets have been considered as another source of insulin-secreting cells for transplantation in T1D patients, though xeno-transplants raise concerns over the risk of endogenous retrovirus transmission and immunological incompatibility. As a result, technological advancements have been made to protect transplanted islets from immune rejection and inflammation, ideally in the absence of chronic immunosuppression, to improve the outcomes and accessibility of allogeneic islet cell replacement therapies. These include the use of microencapsulation or macroencapsulation devices designed to provide an immunoprotective environment using a cell-impermeable layer, preventing immune cell attack of the transplanted cells. Other up and coming advancements are based on the use of stem cells as the starting source material for generating islet cells 'on-demand'. These starting stem cell sources include human induced pluripotent stem cells (hiPSCs) that have been genetically engineered to avoid the host immune response, curated HLA-selected donor hiPSCs that can be matched with recipients within a given population, and multipotent stem cells with natural immune privilege properties. These strategies are developed to provide an immune-evasive cell resource for allogeneic cell therapy. This review will summarize the immunological challenges facing islet transplantation and highlight recent bio-engineering and cell-based approaches aimed at avoiding immune rejection, to improve the accessibility of islet cell therapy and enhance treatment outcomes. Better understanding of the different approaches and their limitations can guide future research endeavors towards developing more comprehensive and targeted strategies for creating a more tolerogenic microenvironment, and improve the effectiveness and sustainability of islet transplantation to benefit more patients.

LINC MIR503HG Controls SC-β Cell Differentiation and Insulin Production by Targeting CDH1 and HES1

Stem cell-derived pancreatic progenitors (SC-PPs), as an unlimited source of SC-derived β (SC-β) cells, offers a robust tool for diabetes treatment in stem cell-based transplantation, disease modeling, and drug screening. Whereas, PDX1+/NKX6.1+ PPs enhances the subsequent endocrine lineage specification and gives rise to glucose-responsive SC-β cells in vivo and in vitro. To identify the regulators that promote induction efficiency and cellular function maturation, single-cell RNA-sequencing is performed to decipher the transcriptional landscape during PPs differentiation. The comprehensive evaluation of functionality demonstrated that manipulating LINC MIR503HG using CRISPR in PP cell fate decision can improve insulin synthesis and secretion in mature SC-β cells, without effects on liver lineage specification. Importantly, transplantation of MIR503HG-/- SC-β cells in recipients significantly restored blood glucose homeostasis, accompanied by serum C-peptide release and an increase in body weight. Mechanistically, by releasing CtBP1 occupying the CDH1 and HES1 promoters, the decrease in MIR503HG expression levels provided an excellent extracellular niche and appropriate Notch signaling activation for PPs following differentiation. Furthermore, this exhibited higher crucial transcription factors and mature epithelial markers in CDH1High expressed clusters. Altogether, these findings highlighted MIR503HG as an essential and exclusive PP cell fate specification regulator with promising therapeutic potential for patients with diabetes.

Clinical translation of pluripotent stem cell-based therapies: successes and challenges

The translational stem cell research field has progressed immensely in the past decade. Development and refinement of differentiation protocols now allows the generation of a range of cell types, such as pancreatic β-cells and dopaminergic neurons, from human pluripotent stem cells (hPSCs) in an efficient and good manufacturing practice-compliant fashion. This has led to the initiation of several clinical trials using hPSC-derived cells to replace lost or dysfunctional cells, demonstrating evidence of both safety and efficacy. Here, we highlight successes from some of the hPSC-based trials reporting early signs of efficacy and discuss common challenges in clinical translation of cell therapies.

Encapsulation and immune protection for type 1 diabetes cell therapy

Type 1 Diabetes (T1D) involves the autoimmune destruction of insulin-producing β-cells in the pancreas. Exogenous insulin injections are the current therapy but are user-dependent and cannot fully recapitulate physiological insulin secretion dynamics. Since the emergence of allogeneic cell therapy for T1D, the Edmonton Protocol has been the most promising immunosuppression protocol for cadaveric islet transplantation, but the lack of donor islets, poor cell engraftment, and required chronic immunosuppression have limited its application as a therapy for T1D. Encapsulation in biomaterials on the nano-, micro-, and macro-scale offers the potential to integrate islets with the host and protect them from immune responses. This method can be applied to different cell types, including cadaveric, porcine, and stem cell-derived islets, mitigating the issue of a lack of donor cells. This review covers progress in the efforts to integrate insulin-producing cells from multiple sources to T1D patients as a form of cell therapy.