Porcine pancreas mesenchymal cell characterization and functional differentiation into insulin‑producing cells in vitro

In Vivo Assessment of the Effects of Mono-Carrier Encapsulated Fucoxanthin Nanoparticles on Type 2 Diabetic C57 Mice and Their Oxidative Stress

Fucoxanthin (FX) is a carotenoid from a marine origin that has an important role in our health, especially in the regulation and alleviation of type 2 diabetes. Its specific molecular structure makes it very unstable, which greatly affects its delivery in the body. In this study, FX was encapsulated in a mono-carrier using a hydrolyzed zein to form a nanocomplex with a stable structure and chemical properties (FZNP). Its stability was demonstrated by characterization and the efficacy of FX before and after encapsulation in alleviating diabetes in mice, which was evaluated by in vivo experiments. FZNP reduced the level of fasting blood glucose and restored it to normal levels in T2DM mice, which was not caused by a decrease in food intake, and effectively reduced oxidative stress in the organism. Both FX and FZNP repaired the hepatocyte and pancreatic β-cell damage, increased serum SOD and reduced INS values significantly, upregulated PI3K-AKT genes as well as CaMK and GNAs expression in the pancreas. FZNP increased ADPN and GSH-PX values more significantly and it decreased serum HOMA-IR and MDA values, upregulated GLUT2 expression, promoted glucose transport in pancreatic and hepatocytes, regulated glucose metabolism and glycogen synthesis with much superior effects than FX.

Mn(II)-Mediated Self-Assembly of Tea Polysaccharide Nanoparticles and Their Functional Role in Mice with Type 2 Diabetes

Tea polysaccharide (TPS) is a bioactive compound that has attracted increasing attention for its health effect on regulating the metabolism of glucose and lipid. Moreover, due to their good biocompatibility and biodegradability, TPS-based nanoparticles have emerged as effective nanocarriers for the delivery of bioactive molecules. In this study, we developed a TPS-based biocarrier system for the orally targeted administration of Mn(II) ions and investigated their antidiabetic effects in C57BL/6 mice with HFD/streptozotocin (STZ)-induced T2DM. Mn(II)-loaded TPS-based nanoparticles (MTNPs) were synthesized, in which negatively charged functional groups in protein and uronic acid in TPS conjugates would act as binding sites for Mn(II) ions, which is responsible for the cross-linking reaction of MTNP. The resulting MTNP had a spherical shape and a mean particle size of around 30 nm with a Mn(II) ion content of 2.24 ± 0.13 mg/g. In T2DM mice, we discovered that MTNP treatment significantly lowered blood glucose levels and improved glucose intolerance. Furthermore, the impact of MTNP on the recovery of FINS, the homeostatic index of insulin resistance (HOMA-IR), and the homeostatic index of β-cell (HOMA β-cell) levels was significantly larger (p < 0.05) than TPS alone, demonstrating that Mn(II) ions can enhance TPS's ability to repair HFD/STZ-induced β-cell damage. Mn(II) ions in MTNP not only acted as cofactors to increase the exocytosis of insulin secretory cells by upregulating the expression of Ca(II)/calmodulin-dependent protein kinase II (CaMK II) but also promoted TPS's lipid-lowering effect in T2DM mice by inhibiting glucogenesis and regulating the lipid metabolism. Our findings suggest that Mn(II) ions can be used not only as cross-linkers in the formation of nanoparticulated TPS but also as cofactors in improving the functional role of TPS in regulating the glucose and lipid metabolism, which will provide insights into the development of TPS-based drug delivery systems for the prevention of type 2 diabetes.

Therapeutic Effects of Insulin-Producing Human Umbilical Cord-Derived Mesenchymal Stem Cells in a Type 1 Diabetes Mouse Model

In patients with type 1 diabetes (T1D), compromised pancreatic β-cell functions are compensated through daily insulin injections or the transplantation of pancreatic tissue or islet cells. However, both approaches are associated with specific challenges. The transplantation of mesenchymal stem cells (MSCs) represents a potential alternative, as MSCs have tissue-forming capacity and can be isolated from various tissues. The human umbilical cord (hUC) is a good source of freely available MSCs, which can be collected through pain-free, non-invasive methods subject to minimal ethical concerns. We sought to develop a method for the in vitro generation of insulin-producing cells (IPCs) using MSCs. We examined the potential therapeutic uses and efficacy of IPCs generated from hUC-derived MSCs (hUC-IPCs) and human adipose tissue (hAD)-derived MSCs (hAD-IPCs) through in vitro experiments and streptozotocin (STZ)-induced C57BL/6 T1D mouse models. We discovered that compared to hAD-IPCs, hUC-IPCs exhibited a superior insulin secretion capacity. Therefore, hUC-IPCs were selected as candidates for T1D cell therapy in mice. Fasting glucose and intraperitoneal glucose tolerance test levels were lower in hUC-IPC-transplanted mice than in T1D control mice and hAD-IPC-transplanted mice. Our findings support the potential use of MSCs for the treatment of T1D.