Enhancement of Subcutaneous Islet Transplant Performance by Collagen 1 Gel.

Human islets can be transplanted into the portal vein for T1 diabetes, and a similar procedure is being used in a clinical trial for stem cell-derived beta-like cells. Efforts have been underway to find an alternative transplant site that will foster better islet cell survival and function. Although conceptually attractive, the subcutaneous (SC) site has yielded disappointing results, in spite of some improvements resulting from more attention paid to vascularization and differentiation factors, including collagen.

Loss-of-function of ALDH3B2 transdifferentiates human pancreatic duct cells into beta-like cells.

Replenishment of pancreatic beta cells is a key to the cure for diabetes. Beta cells regeneration is achieved predominantly by self-replication especially in rodents, but it was also shown that pancreatic duct cells can transdifferentiate into beta cells. How pancreatic duct cells undergo transdifferentiated and whether we could manipulate the transdifferentiation to replenish beta cell mass is not well understood.

Hydrogel Alginate Considerations for Improved 3D Matrix Stability and Cell Graft Viability and Function in Studying Type 1 Diabetes In Vitro.

Biomedical devices such as islet-encapsulating systems are used for treatment of type 1 diabetes (T1D). Despite recent strides in preventing biomaterial fibrosis, challenges remain for biomaterial scaffolds due to limitations on cells contained within. The study demonstrates that proliferation and function of insulinoma (INS-1) cells as well as pancreatic rat islets may be improved in alginate hydrogels with optimized gel%, crosslinking, and stiffness.

Sustained hyperglycemia specifically targets translation of mRNAs for insulin secretion.

Pancreatic β cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair β cell insulin secretion and have been shown experimentally to suppress insulin translation.

Sustained hyperglycemia specifically targets translation of mRNAs for insulin secretion.

Pancreatic β-cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair β-cell insulin secretion and have been shown experimentally to suppress insulin translation.

Identification of a humanized mouse model for functional testing of immune-mediated biomaterial foreign body response.

Biomedical devices comprise a major component of modern medicine, however immune-mediated fibrosis and rejection can limit their function over time. Here, we describe a humanized mouse model that recapitulates fibrosis following biomaterial implantation. Cellular and cytokine responses to multiple biomaterials were evaluated across different implant sites.

Genome-scale in vivo CRISPR screen identifies RNLS as a target for beta cell protection in type 1 diabetes.

Type 1 diabetes (T1D) is caused by the autoimmune destruction of pancreatic beta cells. Pluripotent stem cells can now be differentiated into beta cells, thus raising the prospect of a cell replacement therapy for T1D. However, autoimmunity would rapidly destroy newly transplanted beta cells.

Beta cell identity changes with mild hyperglycemia: Implications for function, growth, and vulnerability.

Objective: As diabetes develops, marked reductions of insulin secretion are associated with very modest elevations of glucose. We wondered if these glucose changes disrupt beta cell differentiation enough to account for the altered function.

Methods: Rats were subjected to 90% partial pancreatectomies and those with only mild glucose elevations 4 weeks or 10 weeks after surgery had major alterations of gene expression in their islets as determined by RNAseq.

A retrievable implant for the long-term encapsulation and survival of therapeutic xenogeneic cells.

The long-term function of transplanted therapeutic cells typically requires systemic immune suppression. Here, we show that a retrievable implant comprising a silicone reservoir and a porous polymeric membrane protects human cells encapsulated in it after implant transplantation in the intraperitoneal space of immunocompetent mice. Membranes with pores 1 µm in diameter allowed host macrophages to migrate into the device without the loss of transplanted cells, whereas membranes with pore sizes <0.

Long-term implant fibrosis prevention in rodents and non-human primates using crystallized drug formulations.

Implantable medical devices have revolutionized modern medicine. However, immune-mediated foreign body response (FBR) to the materials of these devices can limit their function or even induce failure. Here we describe long-term controlled-release formulations for local anti-inflammatory release through the development of compact, solvent-free crystals.

Acceleration of β Cell Aging Determines Diabetes and Senolysis Improves Disease Outcomes.

Type 2 diabetes (T2D) is an age-related disease. Although changes in function and proliferation of aged β cells resemble those preceding the development of diabetes, the contribution of β cell aging and senescence remains unclear. We generated a β cell senescence signature and found that insulin resistance accelerates β cell senescence leading to loss of function and cellular identity and worsening metabolic profile.

Alginate encapsulation as long-term immune protection of allogeneic pancreatic islet cells transplanted into the omental bursa of macaques.

The transplantation of pancreatic islet cells could restore glycaemic control in patients with type-I diabetes. Microspheres for islet encapsulation have enabled long-term glycaemic control in diabetic rodent models; yet human patients transplanted with equivalent microsphere formulations have experienced only transient islet-graft function, owing to a vigorous foreign-body reaction (FBR), to pericapsular fibrotic overgrowth (PFO) and, in upright bipedal species, to the sedimentation of the microspheres within the peritoneal cavity. Here, we report the results of the testing, in non-human primate (NHP) models, of seven alginate formulations that were efficacious in rodents, including three that led to transient islet-graft function in clinical trials.

Generation of Pancreatic Ductal Organoids and Whole-Mount Immunostaining of Intact Organoids.

Traditionally, studies of cells and tissues have been performed on isolated primary cells or immortalized cell lines by culturing them in 2D culture dishes or flasks. However, a caveat regarding 2D culture is that the cells poorly recapitulate their in vivo counterparts, mainly due to a lack of 3D cell-cell and cell-extracellular matrix interactions. In recent years, the development of in vitro organoids as 3D culture has gained substantial attention as a model to study different tissues.

Apolipoprotein E is a pancreatic extracellular factor that maintains mature β-cell gene expression.

The in vivo microenvironment of tissues provides myriad unique signals to cells. Thus, following isolation, many cell types change in culture, often preserving some but not all of their in vivo characteristics in culture. At least some of the in vivo microenvironment may be mimicked by providing specific cues to cultured cells.

Heterogeneity of SOX9 and HNF1β in Pancreatic Ducts Is Dynamic.

Pancreatic duct epithelial cells have been suggested as a source of progenitors for pancreatic growth and regeneration. However, genetic lineage-tracing experiments with pancreatic duct-specific Cre expression have given conflicting results. Using immunofluorescence and flow cytometry, we show heterogeneous expression of both HNF1β and SOX9 in adult human and murine ductal epithelium.

β Cell Aging Markers Have Heterogeneous Distribution and Are Induced by Insulin Resistance.

We hypothesized that the known heterogeneity of pancreatic β cells was due to subpopulations of β cells at different stages of their life cycle with different functional capacities and that further changes occur with metabolic stress and aging. We identified new markers of aging in β cells, including IGF1R. In β cells IGF1R expression correlated with age, dysfunction, and expression of known age markers p16, p53BP1, and senescence-associated β-galactosidase.

Trimeprazine increases IRS2 in human islets and promotes pancreatic β cell growth and function in mice.

The capacity of pancreatic β cells to maintain glucose homeostasis during chronic physiologic and immunologic stress is important for cellular and metabolic homeostasis. Insulin receptor substrate 2 (IRS2) is a regulated adapter protein that links the insulin and IGF1 receptors to downstream signaling cascades. Since strategies to maintain or increase IRS2 expression can promote β cell growth, function, and survival, we conducted a screen to find small molecules that can increase IRS2 mRNA in isolated human pancreatic islets.

The Hypoglycemic Phenotype Is Islet Cell-Autonomous in Short-Chain Hydroxyacyl-CoA Dehydrogenase-Deficient Mice.

Congenital hyperinsulinism of infancy (CHI) can be caused by inactivating mutations in the gene encoding short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD), a ubiquitously expressed enzyme involved in fatty acid oxidation. The hypersecretion of insulin may be explained by a loss of interaction between SCHAD and glutamate dehydrogenase in the pancreatic β-cells. However, there is also a general accumulation of metabolites specific for the enzymatic defect in affected individuals.

Long-term glycemic control using polymer-encapsulated human stem cell-derived beta cells in immune-competent mice.

The transplantation of glucose-responsive, insulin-producing cells offers the potential for restoring glycemic control in individuals with diabetes. Pancreas transplantation and the infusion of cadaveric islets are currently implemented clinically, but these approaches are limited by the adverse effects of immunosuppressive therapy over the lifetime of the recipient and the limited supply of donor tissue. The latter concern may be addressed by recently described glucose-responsive mature beta cells that are derived from human embryonic stem cells (referred to as SC-β cells), which may represent an unlimited source of human cells for pancreas replacement therapy.

MAFA and T3 Drive Maturation of Both Fetal Human Islets and Insulin-Producing Cells Differentiated From hESC.

Context: Human embryonic stem cells (hESCs) differentiated toward β-cells and fetal human pancreatic islet cells resemble each other transcriptionally and are characterized by immaturity with a lack of glucose responsiveness, low levels of insulin content, and impaired proinsulin-to-insulin processing. However, their response to stimuli that promote functionality have not been compared.

Objective: The objective of the study was to evaluate the effects of our previous strategies for functional maturation developed in rodents in these two human models of β-cell immaturity and compare their responses.

Size- and shape-dependent foreign body immune response to materials implanted in rodents and non-human primates.

The efficacy of implanted biomedical devices is often compromised by host recognition and subsequent foreign body responses. Here, we demonstrate the role of the geometry of implanted materials on their biocompatibility in vivo. In rodent and non-human primate animal models, implanted spheres 1.

Reduced Ki67 Staining in the Postmortem State Calls Into Question Past Conclusions About the Lack of Turnover of Adult Human β-Cells.

Some report that adult human β-cells do not replicate, but we postulate this assumption is erroneous due a postmortem decline in replication markers such as Ki67. Our earlier report showed that Ki67-marked β-cells were rarely found in human cadaveric pancreases but were in the range of 0.2-0.

Repurposing cAMP-modulating medications to promote β-cell replication.

Loss of β-cell mass is a cardinal feature of diabetes. Consequently, developing medications to promote β-cell regeneration is a priority. cAMP is an intracellular second messenger that modulates β-cell replication.

Sustained NF-κB activation and inhibition in β-cells have minimal effects on function and islet transplant outcomes.

The activation of the transcription factor NF-κB leads to changes in expression of many genes in pancreatic β-cells. However, the role of NF-κB activation in islet transplantation has not been fully elucidated. The aim of the present study was to investigate whether the state of NF-κB activation would influence the outcome of islet transplantation.