The Current Status of Bioartificial Pancreas Devices

Themes, Rates, and Risk of Adverse Events of the Artificial Pancreas in the United States Using MAUDE

Three manufacturers sell artificial pancreas systems in the United States for management of Type 1 Diabetes. Given the life-saving task required of an artificial pancreas there needs to be a high level of trust and safety in the devices. This evaluation sought to find the adjusted safety event reporting rate and themes along with device-associated risk in events reported utilizing the MAUDE database. We searched device names in the MAUDE database over the period from 2016 until August 2023 (the date of retrieval). Thematic analysis was performed using dual-reviewer examination with a 96% concurrence. Relative risk (RR) was calculated for injury, malfunction, and overall, for each manufacturer, as well as adjusted event rate per manufacturer. Most events reported related to defects in the manufacturing of the casing materials which resulted in non-delivery of therapy. Tandem Diabetes Care, Inc. had an adjusted event rate of 50 per 100,000 units and RR of 0.0225. Insulet had an adjusted event rate of 300 per 100,000 units and RR of 0.1684. Medtronic has an adjusted event rate of 2771.43 per 100,000 units and RR of 20.7857. The newer Medtronic devices show improvements in likely event rate. While the artificial pancreas is still in its infancy, these event rates are not at an acceptable level for a device which can precipitate death from malfunctions. Further exploration into safety events and much more research and development is needed for devices to reduce the event rates. Improved manufacturing practices, especially the casing materials, are highly recommended. The artificial pancreas holds promise for millions but must be improved before it becomes a true life-saving device that it has the potential to become.

Legal and Regulatory Challenges for Emerging Regenerative Medicine Solutions for Diabetes

Regenerative medicine solutions for type 1 diabetes are a rapidly developing field of medical technology. To date, these solutions have been principally cell-based treatments and at present, in Europe, these therapies are regulated under European Union regulations for advanced therapy medicinal products. But now, new emerging technology combining cellular therapy with medical devices is under development. The potential of this novel hybrid model to create a bioartificial pancreas to treat type 1 diabetes is tantalizing. However, incorporating medical devices creates a further layer of regulatory complexity. This article seeks to expose the complexity of this legal and regulatory landscape and demonstrate how evolving technology could challenge the entire existing legal paradigm. We start by summarizing the status of the only established cell-based therapy-transplantation. We set out the regulation of cellular therapies, their classification, and the role of statutory bodies. We examine the bottleneck of therapies moving from bench to bedside, and we consider the additional challenges of products, which use a combination of cells and medical devices. Finally, we argue that for the potential of this rapidly growing area of technology to be realized a seismic shift in how we regulate frontier cellular therapies will be required.

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.

Engineering superstable islets-laden chitosan microgels with carboxymethyl cellulose coating for long-term blood glucose regulation in vivo

Islet transplantation to restore endogenous insulin secretion is a promising therapy for type 1 diabetes in clinic. However, host immune rejection seriously limits the survival of transplanted islets. Despite of the various encapsulation strategies and materials developed so far to provide immune isolation for transplanted islets, long-term blood glucose regulation is still difficult due to the inherent defects of the encapsulation materials. Herein, a novel islet-encapsulation composite material with low immunogenicity, good biocompatibility and excellent stability is reported. Specifically, chitosan (CS) microgels (diameter: ∼302 μm) are prepared via Michael addition reaction between maleimide grafted chitosan (CS-Mal) and thiol grafted chitosan (CS-NAC) in droplet-based microfluidic device, and then zwitterionic surface layer is constructed on CS microgel surface by covalent binding between maleimide groups on CS and thiol groups on thiol modified carboxymethyl cellulose (CMC-SH). The as-formed carboxymethyl cellulose coated chitosan (CS@CMC) microgels show not only long-term stability in vivo owing to the non-biodegradability of CMC, but also fantastic anti-adsorption and antifibrosis because of the stable zwitterionic surface layer. As a result, islets encapsulated in the CS@CMC microgels exhibit high viability and good insulin secretion function in vivo, and long-term blood glucose regulation is achieved for 180 days in diabetic mice post-transplantation.

β1-Integrin-A Key Player in Controlling Pancreatic Beta-Cell Insulin Secretion via Interplay With SNARE Proteins

Shortcomings in cell-based therapies for patients with diabetes have been revealed to be, in part, a result of an improper extracellular matrix (ECM) environment. In vivo, pancreatic islets are emersed in a diverse ECM that provides physical support and is crucial for healthy function. β1-Integrin receptors have been determined to be responsible for modulation of beneficial interactions with ECM proteins influencing beta-cell development, proliferation, maturation, and function. β1-Integrin signaling has been demonstrated to augment insulin secretion by impacting the actin cytoskeleton via activation of focal adhesion kinase and downstream signaling pathways. In other secretory cells, evidence of a bidirectional relationship between integrins and exocytotic machinery has been demonstrated, and, thus, this relationship could be present in pancreatic beta cells. In this review, we will discuss the role of ECM-β1-integrin interplay with exocytotic proteins in controlling pancreatic beta-cell insulin secretion through their dynamic and unique signaling pathway.

Dynamic actuation enhances transport and extends therapeutic lifespan in an implantable drug delivery platform

Fibrous capsule (FC) formation, secondary to the foreign body response (FBR), impedes molecular transport and is detrimental to the long-term efficacy of implantable drug delivery devices, especially when tunable, temporal control is necessary. We report the development of an implantable mechanotherapeutic drug delivery platform to mitigate and overcome this host immune response using two distinct, yet synergistic soft robotic strategies. Firstly, daily intermittent actuation (cycling at 1 Hz for 5 minutes every 12 hours) preserves long-term, rapid delivery of a model drug (insulin) over 8 weeks of implantation, by mediating local immunomodulation of the cellular FBR and inducing multiphasic temporal FC changes. Secondly, actuation-mediated rapid release of therapy can enhance mass transport and therapeutic effect with tunable, temporal control. In a step towards clinical translation, we utilise a minimally invasive percutaneous approach to implant a scaled-up device in a human cadaveric model. Our soft actuatable platform has potential clinical utility for a variety of indications where transport is affected by fibrosis, such as the management of type 1 diabetes.

Drug delivery implants suffer from diminished release profiles due to fibrous capsule formation over time. Here, the authors use soft robotic actuation to modulate the immune response of the host to maintain drug delivery over the longer-term and to perform controlled release in vivo.

J. Schreiber L, Wallace EJ, Wylie R, O'Sullivan J, Dolan EB, Duffy GP. Medical devices, smart drug delivery, wearables and technology for the treatment of Diabetes Mellitus

Diabetes mellitus refers to a group of metabolic disorders which affect how the body uses glucose impacting approximately 9% of the population worldwide. This review covers the most recent technological advances envisioned to control and/or reverse Type 1 diabetes mellitus (T1DM), many of which will also prove effective in treating the other forms of diabetes mellitus. Current standard therapy for T1DM involves multiple daily glucose measurements and insulin injections. Advances in glucose monitors, hormone delivery systems, and control algorithms generate more autonomous and personalised treatments through hybrid and fully automated closed-loop systems, which significantly reduce hypo- and hyperglycaemic episodes and their subsequent complications. Bi-hormonal systems that co-deliver glucagon or amylin with insulin aim to reduce hypoglycaemic events or increase time spent in target glycaemic range, respectively. Stimuli responsive materials for the controlled delivery of insulin or glucagon are a promising alternative to glucose monitors and insulin pumps. By their self-regulated mechanism, these "smart" drugs modulate their potency, pharmacokinetics and dosing depending on patients' glucose levels. Islet transplantation is a potential cure for T1DM as it restores endogenous insulin and glucagon production, but its use is not yet widespread due to limited islet sources and risks of chronic immunosuppression. New encapsulation strategies that promote angiogenesis and oxygen delivery while protecting islets from recipients' immune response may overcome current limiting factors.

Bio-Engineering of Pre-Vascularized Islet Organoids for the Treatment of Type 1 Diabetes

Lack of rapid revascularization and inflammatory attacks at the site of transplantation contribute to impaired islet engraftment and suboptimal metabolic control after clinical islet transplantation. In order to overcome these limitations and enhance engraftment and revascularization, we have generated and transplanted pre-vascularized insulin-secreting organoids composed of rat islet cells, human amniotic epithelial cells (hAECs), and human umbilical vein endothelial cells (HUVECs). Our study demonstrates that pre-vascularized islet organoids exhibit enhanced in vitro function compared to native islets, and, most importantly, better engraftment and improved vascularization in vivo in a murine model. This is mainly due to cross-talk between hAECs, HUVECs and islet cells, mediated by the upregulation of genes promoting angiogenesis (vegf-a) and β cell function (glp-1r, pdx1). The possibility of adding a selected source of endothelial cells for the neo-vascularization of insulin-scereting grafts may also allow implementation of β cell replacement therapies in more favourable transplantation sites than the liver.