Clinical Translation of Bio-Artificial Pancreas Therapies: Ethical, Legal and Psychosocial Interdisciplinary Considerations and Key Recommendations

Assessing Implantation Sites for Pancreatic Islet Cell Transplantation: Implications for Type 1 Diabetes Mellitus Treatment

Type 1 diabetes mellitus (T1DM) involves the destruction of pancreatic β-cells, requiring ongoing insulin therapy. A promising alternative for management is pancreatic islet transplantation, or the bioartificial pancreas. Here, we examine the primary implantation sites for the bioartificial pancreas, highlighting their anatomical, physical, and immunological characteristics in the context of T1DM treatment. Traditionally used for islet transplantation, the liver promotes metabolic efficiency due to portal drainage; however, it presents issues such as hypoxia and inflammatory responses. The omentum offers excellent vascularization but has limited capacity for subsequent transplants. The renal subcapsular space is advantageous when combined with kidney transplants; however, its use is limited due to low vascularization. The subcutaneous space is notable for its accessibility and lower invasiveness, although its poor vascularization poses significant challenges. These challenges can be mitigated with bioengineering strategies. The gastrointestinal submucosa provides easy access and good vascularization, which makes it a promising option for endoscopic approaches. Additionally, the intrapleural space, which remains underexplored, offers benefits such as increased oxygenation and reduced inflammatory response. Selecting the ideal site for bioartificial pancreas implantation should balance graft support, complication reduction, and surgical accessibility. Bioengineered devices and scaffolds can address the limitations of traditional sites and enhance T1DM management.

Recreating the Endocrine Niche: Advances in Bioengineering the Pancreas

Intrahepatic islet transplantation is a promising strategy for β-cell replacement therapy in the treatment of Type 1 Diabetes. However, several obstacles hinder the long-term efficacy of this therapy. A major challenge is the scarcity of donor organs. During the isolation process, islets are disconnected from their extracellular matrix (ECM) and vasculature, leading to significant loss due to anoikis and hypoxia. Additionally, inflammatory and rejection reactions further compromise islet survival and engraftment success. Extensive efforts are being made to improve the efficacy of islet transplantation. These strategies include promoting revascularization and ECM support through bioengineering techniques, exploring alternative sources of insulin-secreting cells, and providing immunomodulation for the graft. Despite these advancements, a significant gap remains in integrating these strategies into a cohesive approach that effectively replicates the native endocrine environment. Specifically, the lack of comprehensive methods to address both the structural and functional aspects of the endocrine niche limits reproducibility and clinical translation. Therefore, bioengineering an endocrine pancreas must aim to recreate the endocrine niche to achieve lifelong efficacy and insulin independence. This review discusses various strategies developed to produce the building blocks for generating a vascularized, immune-protected insulin-secreting construct, emphasizing the importance of the endocrine niche's composition and function.

Current Challenges in Pancreas and Islet Transplantation: A Scoping Review

Type 1 diabetes mellitus is an autoimmune condition characterized by the destruction of pancreatic β-cells, necessitating insulin therapy to prevent life-threatening complications such as diabetic ketoacidosis. Despite advancements in glucose monitoring and pharmacological treatments, managing this disease remains challenging, often leading to long-term complications and psychological burdens, including diabetes distress. Advanced treatment options, such as whole-pancreas transplantation and islet transplantation, aim to restore insulin production and improve glucose control in selected patients with diabetes. The risk of transplant rejection necessitates immunosuppressive therapy, which increases susceptibility to infections and other adverse effects. Additionally, surgical complications, including infection and bleeding, are significant concerns, particularly for whole-pancreas transplantation. Recently, stem cell-derived therapies for type 1 diabetes have emerged as a promising alternative, offering potential solutions to overcome the limitations of formerly established transplantation methods. The purpose of this scoping review was to: (1) summarize the current evidence on achieved insulin independence following various transplantation methods of insulin-producing cells in patients with type 1 diabetes; (2) compare insulin independence rates among whole-pancreas transplantation, islet cell transplantation, and stem cell transplantation; and (3) identify limitations, challenges and potential future directions associated with these techniques. We systematically searched three databases (PubMed, Scopus, and Web of Science) from inception to November 2024, focusing on English-language, peer-reviewed clinical studies. The search terms used were 'transplantation' AND 'type 1 diabetes' AND 'insulin independence'. Studies were included if they reported on achieved insulin independence, involved more than 10 patients with type 1 diabetes, and had a mean follow-up period of at least one year. Reviewers screened citations and extracted data on transplant type, study population size, follow-up duration, and insulin independence rates. We identified 1380 papers, and after removing duplicates, 705 papers remained for title and abstract screening. A total of 139 English-language papers were retrieved for full-text review, of which 48 studies were included in this review. The findings of this scoping review indicate a growing body of literature on transplantation therapy for type 1 diabetes. However, significant limitations and challenges, like insufficient rates of achieved insulin independence, risks related to immunosuppression, malignant diseases, and ethical issues remain with each of the established techniques, highlighting the need for innovative approaches such as stem cell-derived islet transplantation to promote β-cell regeneration and protection.

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.