Search

Islet delivery devices (IDDs) offer potential benefits for islet transplantation and stem cell-based replacement in type 1 diabetes. Little is known about patient preferences regarding islet delivery device characteristics and implantation strategies. Patient preferences for IDDs and implantation strategies remain understudied. We invited patients, parents and caregivers to fill in an online questionnaire regarding IDDs. An online survey gathered responses from 809 type 1 diabetes patients and 47 caregivers. We also assessed diabetes distress in a subgroup of 412 patients. A significant majority (97%) expressed willingness to receive an IDD. Preferred IDD attributes included a 3.5 cm diameter for 37.7% of respondents, while when provided with all options, 30.4% found dimensions unimportant. Respondents were open to approximately 4 implants, each with a 5 cm incision. Many favored a device functioning for 12 months (33.4%) or 24 months (24.8%). Younger participants (16-30) were more inclined to accept a 6 months functional duration ( p < 0.001). Functional duration outweighed implant quantity and size ( p < 0.001) in device importance. This emphasizes patients' willingness to accommodate burdens related to IDD features and implantation methods, crucial for designing future beta cell replacement strategies.

The field of transplantation has witnessed the emergence of Advanced Therapy Medicinal Products (ATMPs) as highly promising solutions to address the challenges associated with organ and tissue transplantation. ATMPs encompass gene therapy, cell therapy, and tissue-engineered products, hold immense potential for breakthroughs in overcoming the obstacles of rejection and the limited availability of donor organs. However, the development and academic research access to ATMPs face significant bottlenecks that hinder progress. This opinion paper emphasizes the importance of addressing bottlenecks in the development and academic research access to ATMPs by implementing several key strategies. These include the establishment of streamlined regulatory processes, securing increased funding for ATMP research, fostering collaborations and partnerships, setting up centralized ATMP facilities, and actively engaging with patient groups. Advocacy at the policy level is essential to provide support for the development and accessibility of ATMPs, thereby driving advancements in transplantation and enhancing patient outcomes. By adopting these strategies, the field of transplantation can pave the way for the introduction of innovative and efficacious ATMP therapies, while simultaneously fostering a nurturing environment for academic research.

The clinical success rate of islet transplantation, namely independence from insulin injections, is limited by factors that lead to graft failure, including inflammation, acute ischemia, acute phase response, and insufficient vascularization. The ischemia and insufficient vascularization both lead to high levels of oxidative stress, which are further aggravated by islet encapsulation, inflammation, and undesirable cell-biomaterial interactions. To identify biomaterials that would not further increase damaging oxidative stress levels and that are also suitable for manufacturing a beta cell encapsulation device, we studied five clinically approved polymers for their effect on oxidative stress and islet (alpha and beta cell) function. We found that 300 poly(ethylene oxide terephthalate) 55/poly(butylene terephthalate) 45 (PEOT/PBT300) was more resistant to breakage and more elastic than other biomaterials, which is important for its immunoprotective function. In addition, it did not induce oxidative stress or reduce viability in the MIN6 beta cell line, and even promoted protective endogenous antioxidant expression over 7 days. Importantly, PEOT/PBT300 is one of the biomaterials we studied that did not interfere with insulin secretion in human islets.

Macroencapsulation of islets of Langerhans is a promising strategy for transplantation of insulin-producing cells in the absence of immunosuppression to treat type 1 diabetes. Hollow fiber membranes are of interest there because they offer a large surface-to-volume ratio and can potentially be retrieved or refilled. However, current available fibers have limitations in exchange of nutrients, oxygen, and delivery of insulin potentially impacting graft survival. Here, multibore hollow fibers for islets encapsulation are designed and tested. They consist of seven bores and are prepared using nondegradable polymers with high mechanical stability and low cell adhesion properties. Human islets encapsulated there have a glucose induced insulin response (GIIS) similar to nonencapsulated islets. During 7 d of cell culture in vitro, the GIIS increases with graded doses of islets demonstrating the suitability of the microenvironment for islet survival. Moreover, first implantation studies in mice demonstrate device material biocompatibility with minimal tissue responses. Besides, formation of new blood vessels close to the implanted device is observed, an important requirement for maintaining islet viability and fast exchange of glucose and insulin. The results indicate that the developed fibers have high islet bearing capacity and can potentially be applied for a clinically applicable bioartificial pancreas.

Intrahepatic islet transplantation is a promising therapy for treatment of type 1 diabetes. During islet isolation, collagenase is used to extract islets from the pancreas, leading to loss of important cell-matrix interactions. Loss of the native pancreatic microenvironment is associated with apoptosis of islet cells, early graft failure, and poor islet function. The islet extracellular matrix (ECM) is composed of a specific combination of collagen (Col), laminin (LN), and fibronectin (FN) molecules. Reintroducing these molecules has been shown to boost the function, viability, morphology, and proliferation of beta-cells. In this research, the effect of combinatorial ECM on islet function and survival was investigated. Specifically, thin-film microwell array scaffolds made from two distinct biomaterials were coated with FN, collagen type IV (Col4), LN111, LN332, or a combination thereof. We found that coatings containing a single type of ECM molecule, for example, FN or Col, can improve short-term islet function. However, these single proteins do not prevent loss of morphology and subsequent loss of islet function afterward. In contrast, combining Col4 with LN111 at a ratio of 8:2 not only improved short-term islet function but also preserved islet structure and islet function on a longer term. This effect was reproducibly shown on poly(ester-urethane) and poly(ethylene-glycol-terephthalate-poly(butylene-terephthalate) microwell islet delivery devices as well as tissue culture polystyrene. We concluded that biofunctionalization of inert biomaterials regardless of their molecular composition with a specific combination of islet ECM molecules can support and improve islet function over longer time periods. Our data suggested that creating a biomimetic islet niche by biofunctionalization of biomaterials can significantly improve the endocrine function of beta-cells. The creation of islet mimicking niches in islet delivery devices leads to an improvement of islet fun

Extracellular matrix (ECM) molecules play significant roles in regulating -cell function and viability within pancreatic islets by providing mechanical and biological support, stimulating cell survival, proliferation, and their endocrine function. During clinical islet transplantation, the -cell's ECM environment is degraded by enzymatic digestion. Literature suggests that interactions between islet cells and ECM molecules, such as fibronectin (FN), collagen type IV (Col4), and laminin (LN), are essential for maintaining, or stimulation of islet function and survival, and can effect differentiation and proliferation of the endocrine cells. It is also thought that three-dimensional (3D) culture of -cells can improve glucose responsiveness by providing a specific niche, in which cells can interact with each other in a more natural manner. Conventional suspension cultures with -cells results generally in a heterogeneous population with small and large aggregates, in which cells experience different nutrient diffusion limitations, negatively affecting their physiology and function. In this study, we have explored the effect of FN, Col4, and LN111 on INS1E insulinoma cells by using microcontact printing (CP) to investigate whether a controlled environment and aggregate dimensions would improve their endocrine function. Using this method, we produced a pattern of well-defined circular spots of FN, Col4, and LN111 on polydimethylsiloxane with high spatial resolution. Cell seeding of the INS1E cells on these ECM protein spots resulted in the formation of 3D -cell aggregates. We show that these INS1E aggregates have very reproducible dimensions, and that the cell culture method can be easily adjusted, leading to a highly accurate way of forming 3D -cell aggregates on an ECM-functionalized substrate. In addition, we show that ECM molecules can act as anchoring points for -cells on an otherwise non-cell-adherent material, and this can improve both the endocrine function and

Allogeneic islet transplantation into the liver in combination with immune suppressive drug therapy is widely regarded as a potential cure for type 1 diabetes. However, the intrahepatic system is suboptimal as the concentration of drugs and nutrients there is higher compared to pancreas, which negatively affects islet function. Islet encapsulation within semipermeable membranes is a promising strategy that allows for the islet transplantation outside the suboptimal liver portal system and provides environment, where islets can perform their endocrine function. In this study, we develop a macroencapsulation device based on thin microwell membranes. The islets are seeded in separate microwells to avoid aggregation, whereas the membrane porosity is tailored to achieve sufficient transport of nutrients, glucose and insulin. The non-degradable, microwell membranes are composed of poly (ether sulfone)/polyvinylpyrrolidone and manufactured via phase separation micro molding. Our results show that the device prevents aggregation and preserves the islet's native morphology. Moreover, the encapsulated islets maintain their glucose responsiveness and function after 7 days of culture (stimulation index above 2 for high glucose stimulation), demonstrating the potential of this novel device for islet transplantation.