Diabetes results from the inability of pancreatic islets to maintain blood glucose concentrations within a normal physiological range. Clinical features are usually not observed until islets begin to fail and irreversible damage has occurred. Diabetes is generally diagnosed based on elevated glucose, which does not distinguish between type 1 and 2 diabetes. Thus, new diagnostic approaches are needed to detect different modes of diabetes before manifestation of disease. During prediabetes (pre-DM), islets undergo stress and release micro (mi) RNAs. Here, we review studies that have measured and tracked miRNAs in the blood for those with recent-onset or longstanding type 1 diabetes, obesity, pre-diabetes, type 2 diabetes, and gestational diabetes. We summarize the findings on miRNA signatures with the potential to stage progression of different modes of diabetes. Advances in identifying selective biomarker signatures may aid in early detection and classification of diabetic conditions and treatments to prevent and reverse diabetes.

Exosomes are known for their ability to transport nucleic acid, lipid, and protein molecules, which allows for communication between cells and tissues. The cargo of the exosomes can have a variety of effects on a wide range of targets to mediate biological function. Pancreatic islet transplantation is a minimally invasive cell replacement therapy to prevent or reverse diabetes mellitus and is currently performed in patients with uncontrolled type 1 diabetes or chronic pancreatitis. Exosomes have become a focus in the field of islet transplantation for the study of diagnostic markers of islet cell viability and function. A growing list of miRNAs identified from exosomes collected during the process of isolating islets can be used as diagnostic biomarkers of islet stress and damage, leading to a better understanding of critical steps of the isolation procedure that can be improved to increase islet yield and quality. Exosomes have also been implicated as a possible contributor to islet graft rejection following transplantation, as they carry donor major histocompatibility complex molecules, which are then processed by recipient antigen-presenting cells and sensed by the recipient immune cells. Exosomes may find their way into the therapeutic realm of islet transplantation, as exosomes isolated from mesenchymal stem cells have shown promising results in early studies that have seen increased viability and functionality of isolated and grafted isletsin vitroas well asin vivo. With the study of exosomes still in its infancy, continued research on the role of exosomes in islet transplantation will be paramount to understanding beta cell regeneration and improving long-term graft function.

Islet transplantation is a therapeutic option to replace β-cell mass lost during type 1 or type 3c diabetes. Innate immune responses, particularly the instant blood-mediated inflammatory reaction and activation of monocytes, play a major role in the loss of transplanted islet tissue. In this study, we aimed to investigate the inhibition of toll-like receptor 4 (TLR4) on innate inflammatory responses. We first demonstrate a significant loss of graft function shortly after transplant through the assessment of miR-375 and miR-200c in plasma as biomarkers. Using in vitro models, we investigate how targeting TLR4 mitigates islet damage and immune cell activation during the peritransplant period. The results of this study support the application of TAK-242 as a therapeutic agent to reduce inflammatory and innate immune responses to islets immediately following transplantation into the hepatic portal vein. Therefore, TLR4 may serve as a target to improve islet transplant outcomes in the future.

In patients with chronic pancreatitis, pancreatic calcification is a risk factor for diabetes development, poor islet yield, and metabolic outcomes after total pancreatectomy with islet autotransplantation (TPIAT). We investigated whether calcification pattern based on computed tomography is associated with outcomes using our database of 200 consecutive TPIAT procedures. Three groups were compared: noncalcification (NC); focal calcification (FC), limited to the pancreas head, body, or tail; and diffuse calcification (DC), with calcification in >2 sections. Maximum changes in outcomes were seen in the DC vs FC group. In the DC group, preoperative hemoglobin A1c levels were higher (P < 0.01) and stimulated C-peptide levels were lower (P < 0.01) than in the NC group. Islet isolation from the DC pancreas resulted in the lowest islet yield (IEQ) and IEQ/kg among the three groups (P < 0.0001) with no insulin independence 12 months posttransplant (P < 0.05 vs NC). Notably, at 12 months, the DC group was 91.7% narcotic free, significantly higher than the NC group (P < 0.05). Although DC is a sign of diabetes risk after TPIAT, the DC group showed exceptional pain relief. These findings suggest that TPIAT can be beneficial for patients with chronic pancreatitis with severe calcification.

Diabetes mellitus remains a leading cause of morbidity worldwide, driven in type 1 diabetes by autoimmune destruction of pancreatic β-cells and in advanced type 2 diabetes by progressive β-cell dysfunction and failure. Diabetes affects around 830 million people globally, with the vast majority residing within low- and middle-income nations. Over the last few decades, the numbers of people who have diabetes and those with untreated diabetes have consistently increased. Although current pharmacologic therapies improve glycemic control, they do not restore functional β-cell mass. Consequently, strategies aimed at protecting, regenerating, or replacing insulin-producing cells have emerged as a major focus of regenerative medicine. Stem cell-based approaches offer the potential to generate renewable sources of glucose-responsive β-like cells, but challenges remain in achieving full functional maturation, immune protection, scalable manufacturing, and durable clinical engraftment. This review examines advances in engineering stem cell-derived insulin-producing cells for islet replacement therapy, with an emphasis on differentiation strategies, immunoprotective approaches, and the translational barriers that must be addressed for durable β-cell replacement.