Microencapsulation-based cell therapies

Establishment of subcutaneous transplantation platform for delivering induced pluripotent stem cell-derived insulin-producing cells

Potential trend of regenerative treatment for type I diabetes has been introduced for more than a decade. However, the technologies regarding insulin-producing cell (IPC) production and transplantation are still being developed. Here, we propose the potential IPC production protocol employing mouse gingival fibroblast-derived induced pluripotent stem cells (mGF-iPSCs) as a resource and the pre-clinical approved subcutaneous IPC transplantation platform for further clinical confirmation study. With a multi-step induction protocol, the functional and matured IPCs were generated by 13 days with a long-term survival capability. Further double encapsulation of mGF-iPSC-derived IPCs (mGF-iPSC-IPCs) could preserve the insulin secretion capacity and the transplantation potential of the generated IPCs. To address the potential on IPC transplantation, a 2-step subcutaneous transplantation procedure was established, comprising 1) vascularized subcutaneous pocket formation and 2) encapsulated IPC bead transplantation. The in vivo testing confirmed the safety and efficiency of the platform along with less inflammatory response which may help minimize tissue reaction and graft rejection. Further preliminary in vivo testing on subcutaneous IPC-bead transplantation in an induced type I diabetic mouse model showed beneficial trends on blood glucose control and survival rate sustainability of diabetic mice. Taken together, an established mGF-iPSC-IPC generation protocol in this study will be the potential backbone for developing the iPSC-derived IPC production employing human and animal cell resources. As well as the potential further development of IPC transplantation platform for diabetes treatment in human and veterinary practices using an established subcutaneous encapsulated IPC-bead transplantation platform presented in this study.

Biotechnology Revolution Shaping the Future of Diabetes Management

INTRODUCTION

Diabetes mellitus (DM) has a millennia-long history, with early references dating back to ancient Egypt and India. However, it was not until the 20th century that the connection between diabetes and insulin was fully understood. The sequencing of insulin in the 1950s initiated the convergence of biotechnology and diabetes management, leading to the development of recombinant human insulin in 1982. This marked the start of peptide-based therapies in DM. Recombinant peptides for DM treatment: Numerous recombinant peptides have been developed since, starting with modified insulin molecules, with the aim of bettering DM management through fine-tuning the glycemic response to insulin. Peptide-based therapies in DM have expanded substantially beyond insulin to include agonists of Glucagon-like peptide-1 receptor and Glucose-dependent insulinotropic polypeptide receptor, glucagon receptor antagonists, and even peptides exerting multiple receptor agonist effects, for better metabolic control. Insulin pumps, continuous glucose monitoring, and automated insulin delivery systems: The development of modern delivery systems combined with real-time glucose monitoring has significantly advanced diabetes care. Insulin pumps evolved from early large devices to modern sensor-augmented pumps with automated shutoff features and hybrid closed-loop systems, requiring minimal user input. The second-generation systems have demonstrated superior outcomes, proving highly effective in diabetes management. Islet cell transplantation, organoids, and biological pancreas augmentation represent innovative approaches to diabetes management. Islet cell transplantation aims to restore insulin production by transplanting donor beta cells, though challenges persist regarding graft survival and the need for immunosuppression. Organoids are a promising platform for generating insulin-producing cells, although far from clinical use. Biological pancreas augmentation relies on therapies that promote beta-cell (re)generation, reduce stress, and induce immune tolerance. Further biotechnology-driven perspectives in DM will include metabolic control via biotechnology-enabled tools such as custom-designed insulin hybrid molecules, machine-learning algorithms to control peptide release, and engineering cells for optimal peptide production and secretion.

Microencapsulation and nanoencapsulation of bacterial probiotics: new frontiers in Alzheimer's disease treatment

Alzheimer's disease, a progressive neurodegenerative disorder marked by cognitive decline, affects millions worldwide. The presence of amyloid plaques and neurofibrillary tangles in the brain is the key pathological feature, leading to neuronal dysfunction and cell death. Current treatment options include pharmacological approaches such as cholinesterase inhibitors, as well as non-pharmacological strategies like cognitive training and lifestyle modifications. Recently, the potential role of probiotics, particularly strains, such as Lactobacillus and Bifidobacterium, in managing neurodegenerative diseases through the gut-brain axis has garnered significant attention. Probiotics can modulate inflammation, produce neurotransmitters, and support neuronal health, potentially slowing disease progression and alleviating symptoms, such as stress and anxiety. Optimizing the pharmacotherapeutic effects of probiotics is critical and involves advanced formulation techniques, such as microencapsulation and nanoencapsulation. Microencapsulation employs natural or synthetic polymers to protect probiotic cells, enhancing their viability and stability against environmental stressors. Methods like extrusion, emulsion, and spray-drying are used to create microcapsules suited for various applications. Nanoencapsulation, on the other hand, operates at the nanoscale, utilizing polymeric or lipid-based nanoparticles to improve the bioavailability and shelf life of probiotics. Techniques, such as nanoprecipitation and emulsification, are employed to ensure stable nanocapsule formation, thereby augmenting the therapeutic potential of probiotics as nutraceutical agents. This study delves into the essential formulation aspects of microencapsulation and nanoencapsulation for beneficial probiotic strains, aimed at managing Alzheimer's disease by optimizing the gut-brain axis. The insights gained from these advanced techniques promise to enhance probiotic delivery efficacy, potentially leading to improved health outcomes for patients suffering from neurodegenerative disorders.

A generic cell-based biosensor converts bacterial infection signals into chemoattractants for immune cells

Bacterial infection is a major challenge to human health. Although various potent antibiotics have emerged in recent decades, current challenges arise from the increasing number of multi-drug-resistant species. Infections associated with implants represent a particular challenge because they are usually diagnosed at an advanced stage and are difficult to treat with antibiotics owing to the formation of protective biofilms. In this study, we designed and explored a synthetic biology-inspired cell-based biosensor/actor for the detection and counteraction of bacterial infections. The system is generic, as it senses diverse types of infections and acts by enhancing the endogenous immune system. This strategy is based on genetically engineered sensor/actor cells that can sense type I interferons (IFNs), which are released by immune cells at the early stages of infection. IFN signalling activates a synthetic circuit to induce reporter genes with a sensitivity of only 5 pg ml-1of IFN and leads to a therapeutic protein output of 100 ng ml-1, resulting in theranostic cells that can visualize and fight infections. Robustness and resilience were achieved by implementing a positive feedback loop. We showed that diverse gram-positive and gram-negative implant-associated pathogenic bacteria activate the cascade in co-culture systems in a dose-dependent manner. Finally, we showed that this system can be used to secrete chemoattractants that facilitate the infiltration of immune cells in response to bacterial triggers. Together, the system is not only universal to bacterial infections, but also hypersensitive, allowing the sensing of infections at initial stages.

Angiogenesis unveiled: Insights into its role and mechanisms in cartilage injury

Osteoarthritis (OA) commonly results in compromised mobility and disability, thereby imposing a significant burden on healthcare systems. Cartilage injury is a prevalent pathological manifestation in OA and constitutes a central focus for the development of treatment strategies. Despite the considerable number of studies aimed at delaying this degenerative process, their outcomes remain unvalidated in preclinical settings. Recently, therapeutic strategies focused on angiogenesis have attracted the growing interest from researchers. Thus, we conducted a comprehensive literature review to elucidate the current progress in research and pinpoint research gaps in this domain. Additionally, it provides theoretical guidance for future research endeavors and the development of treatment strategies.

Probing of New Polymer-Based Microcapsules for Islet Cell Immunoisolation

Islet allotransplantation offers a promising cell therapy for type 1 diabetes, but challenges such as limited donor availability and immunosuppression persist. Microencapsulation of islets in polymer-coated alginate microcapsules is a favored strategy for immune protection and maintaining islet viability. This study introduces Poly [2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) as an innovative coating material for microcapsules. PMETAC enhances biocompatibility and durability, marking a significant advancement in islet encapsulation. Our approach combines alginate with PMETAC to create Langerhans islet microcapsules, simplifying material composition and preparation and ultimately lowering costs and increasing clinical applicability. Our comprehensive evaluation of the stability (including osmotic stability, thermal stability, and culture condition stability) and cytotoxicity of a novel microencapsulation system based on alginate-PMETAC-alginate offers insights into its potential application in islet immunoisolation strategies. Microcapsules with PMETAC content ranging from 0.01 to 1% are explored in the current work. The results indicate that the coatings made with 0.4% PMETAC show the most promising outcomes, remaining stable in the mentioned tests and exhibiting the required permeability. It was shown that the islets encapsulated in this manner retain viability and functional activity. Thus, alginate microcapsules coated with 0.4% PMETAC are suitable for further animal trials. While our findings are promising, further studies, including animal testing, will be necessary to evaluate the clinical applicability of our encapsulation method.

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.

Advances of Schwann cells in peripheral nerve regeneration: From mechanism to cell therapy

Peripheral nerve injuries (PNIs) frequently occur due to various factors, including mechanical trauma such as accidents or tool-related incidents, as well as complications arising from diseases like tumor resection. These injuries frequently result in persistent numbness, impaired motor and sensory functions, neuropathic pain, or even paralysis, which can impose a significant financial burden on patients due to outcomes that often fall short of expectations. The most frequently employed clinical treatment for PNIs involves either direct sutures of the severed ends or bridging the proximal and distal stumps using autologous nerve grafts. However, autologous nerve transplantation may result in sensory and motor functional loss at the donor site, as well as neuroma formation and scarring. Transplantation of Schwann cells/Schwann cell-like cells has emerged as a promising cellular therapy to reconstruct the microenvironment and facilitate peripheral nerve regeneration. In this review, we summarize the role of Schwann cells and recent advances in Schwann cell therapy in peripheral nerve regeneration. We summarize current techniques used in cell therapy, including cell injection, 3D-printed scaffolds for cell delivery, cell encapsulation techniques, as well as the cell types employed in experiments, experimental models, and research findings. At the end of the paper, we summarize the challenges and advantages of various cells (including ESCs, iPSCs, and BMSCs) in clinical cell therapy. Our goal is to provide the theoretical and experimental basis for future treatments targeting peripheral nerves, highlighting the potential of cell therapy and tissue engineering as invaluable resources for promoting nerve regeneration.

Global scientific trends on the islet transplantation in the 21st century: A bibliometric and visualized analysis

BACKGROUND

Islet transplantation (IT) has emerged as a significant research area for the treatment of diabetes mellitus and has witnessed a surge in scholarly attention. Despite its growing importance, there is a lack of bibliometric analyses that encapsulate the evolution and scientific underpinnings of this field. This study aims to fill this gap by conducting a comprehensive bibliometric analysis to delineate current research hotspots and forecast future trajectories within the IT domain with a particular focus on evidence-based medicine practices.

METHODS

This analysis scrutinized literature from January 1, 2000, to October 1, 2023, using the Web of Science Core Collection (WoSCC). Employing bibliometric tools such as VOSviewer, CiteSpace, and the R package "bibliometrix," we systematically evaluated the literature to uncover scientific trends and collaboration networks in IT research.

RESULTS

The analysis revealed 8388 publications from 82 countries, predominantly the United States and China. However, global cross-institutional collaboration in IT research requires further strengthening. The number of IT-related publications has increased annually. Leading research institutions in this field include Harvard University, the University of Alberta, the University of Miami, and the University of Minnesota. "Transplantation" emerges as the most frequently cited journal in this area. Shapiro and Ricordi were the most prolific authors, with 126 and 121 publications, respectively. Shapiro also led to co-citations, totaling 4808. Key research focuses on IT sites and procedures as well as novel therapies in IT. Emerging research hotspots are identified by terms like "xenotransplantation," "apoptosis," "stem cells," "immunosuppression," and "microencapsulation."

CONCLUSIONS

The findings underscore a mounting anticipation for future IT research, which is expected to delve deeper into evidence-based methodologies for IT sites, procedures, and novel therapeutic interventions. This shift toward evidence-based medicine underscores the field's commitment to enhancing the efficacy and safety of IT for diabetes treatment, signaling a promising direction for future investigations aimed at optimizing patient outcomes.

A Bioartificial Pancreas with "Immune Stealth" and Continuous Oxygen Supply for Islet Transplantation

Transplantation of microencapsulated islet cells remains a promising strategy for the normalization of glucose metabolism control in type 1 diabetes mellitus. However, vigorous host immunologic rejection, fibrotic overgrowth around the microcapsules, and poor oxygen supply often lead to graft failure. Herein, a bioartificial pancreas is constructed, which incorporates the "stealth effect" based on polyethylene glycol copolymers and the high oxygen-carrying performance of fluorinated nanoparticles. Polycationic poly(l-lysine)-grafted-poly(ethylene glycol) is successfully coated on the surface of alginate microcapsules through electrostatic interaction, which can not only resist fibrinogen adhesion and avoid excessive fibrosis around the microcapsules but also isolate the host immune system from attacking, achieving a "stealth effect" of microencapsulated islet cells. Furthermore, the coloading of fluoride-based O2 nanocarriers gives them enhanced oxygen-carrying and continuous oxygen supply capabilities, thereby effectively prolonging the survival of islet cells. The intracapsular islet cells still display similar cell viability and almost normal insulin secretion function even in long-term culture under hypoxic conditions. Collectively, here a new approach is opened for microencapsulated islets to efficiently evade host immune attack and improve oxygen supply and a promising strategy is provided for islet transplantation in type 1 diabetes mellitus.

A review on chitosan and alginate-based microcapsules: Mechanism and applications in drug delivery systems

Natural polymers, like chitosan and alginate have potential of appearance, as well as the changes and handling necessary to make it acceptable vehicle for the controlled release of medicines and biomolecules. Microcapsules are characterized as micrometer-sized particulate that can be employed to store chemicals within them. In the present review, we have discussed various advantages, components of microcapsules, release mechanisms, preparation methods, and their applications in drug delivery systems. The preparation methods exhibited strong encapsulation effectiveness and may be used in a wide range of pharmaceutical and biomedical applications. The major advantages of using the microencapsulation technique are, sustained and controlled delivery of drugs, drug targeting, improvement of shelf life, stabilization, immobilization of enzymes and microorganisms. As new biomaterials are developed for the body, they are better suited to the development of pharmaceutical systems than traditional pharmaceuticals because they are more reliable, biocompatible, biodegradable, and nontoxic. Furthermore, the designed microcapsules had been capable of shielding the essential components from hostile environments. More advanced techniques could be developed in the future to facilitate the formulation and applications of microcapsules and working with the pharmaceutical and medical industries.

Engineering a material-genetic interface as safety switch for embedded therapeutic cells

Encapsulated cell-based therapies involve the use of genetically-modified cells embedded in a material in order to produce a therapeutic agent in a specific location in the patient's body. This approach has shown great potential in animal model systems for treating diseases such as type I diabetes or cancer, with selected approaches having been tested in clinical trials. Despite the promise shown by encapsulated cell therapy, though, there are safety concerns yet to be addressed, such as the escape of the engineered cells from the encapsulation material and the resulting production of therapeutic agents at uncontrolled sites in the body. For that reason, there is great interest in the implementation of safety switches that protect from those side effects. Here, we develop a material-genetic interface as safety switch for engineered mammalian cells embedded into hydrogels. Our switch allows the therapeutic cells to sense whether they are embedded in the hydrogel by means of a synthetic receptor and signaling cascade that link transgene expression to the presence of an intact embedding material. The system design is highly modular, allowing its flexible adaptation to other cell types and embedding materials. This autonomously acting switch constitutes an advantage over previously described safety switches, which rely on user-triggered signals to modulate activity or survival of the implanted cells. We envision that the concept developed here will advance the safety of cell therapies and facilitate their translation to clinical evaluation.

Freezing biological organisms for biomedical applications

Biological organisms play important roles in human health, either in a commensal or pathogenic manner. Harnessing inactivated organisms or living organisms is a promising way to treat diseases. As two types of freezing, cryoablation makes it simple to inactivate organisms that must be in a non-pathogenic state when needed, while cryopreservation is a facile way to address the problem of long-term storage challenged by living organism-based therapy. In this review, we present the latest studies of freezing biological organisms for biomedical applications. To begin with, the freezing strategies of cryoablation and cryopreservation, as well as their corresponding technical essentials, are illustrated. Besides, biomedical applications of freezing biological organisms are presented, including transplantation, tissue regeneration, anti-infection therapy, and anti-tumor therapy. The challenges and prospects of freezing living organisms for biomedical applications are well discussed. We believe that the freezing method will provide a potential direction for the standardization and commercialization of inactivated or living organism-based therapeutic systems, and promote the clinical application of organism-based therapy.