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Patients with diabetes mellitus have up to a 15% lifetime risk of non-healing and poorly healing wounds. This work develops core-shell nanofibrous bioactive insulin-loaded poly-D-L-lactide-glycolide (PLGA) scaffolds that release insulin in a sustained manner for repairing wounds in diabetic rats. To prepare the biodegradable core-shell nanofibers, PLGA and insulin solutions were fed into two capillary tubes of different sizes that were coaxially electrospun using two independent pumps. The scaffolds sustainably released insulin for four weeks. The hydrophilicity and water-containing capacity of core-shell nanofibrous insulin/PLGA scaffolds significantly exceeded those of blended nanofibrous scaffolds. The nanofibrous core-shell insulin-loaded scaffold reduced the amount of type I collagen in vitro, increased the transforming growth factor-beta content in vivo, and promoted diabetic would repair. The core-shell insulin-loaded nanofibrous scaffolds prolong the release of insulin and promote diabetic wound healing.
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Vendajes , Diabetes Mellitus Experimental/tratamiento farmacológico , Angiopatías Diabéticas/tratamiento farmacológico , Insulina , Nanofibras , Animales , Preparaciones de Acción Retardada/química , Preparaciones de Acción Retardada/farmacocinética , Preparaciones de Acción Retardada/farmacología , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patología , Angiopatías Diabéticas/metabolismo , Angiopatías Diabéticas/patología , Insulina/química , Insulina/farmacocinética , Insulina/farmacología , Nanofibras/química , Nanofibras/uso terapéutico , Ratas , Ratas Sprague-DawleyRESUMEN
Microscopic examination of transplanted islets in an ectopic environment provides information to evaluate islet engraftment, including revascularization and reinnervation. However, because of the dispersed nature of blood vessels and nerves, global visualization of the graft neurovascular network has been difficult. In this research we revealed the neurovascular network by preparing transparent mouse islet grafts under the kidney capsule with optical clearing to investigate the sympathetic reinnervation via three-dimensional confocal microscopy. Normoglycemic and streptozotocin-induced diabetic mice were used in syngeneic islet transplantation, with both groups maintaining euglycemia after transplantation. Triple staining of insulin/glucagon, blood vessels, and tyrosine hydroxylase (sympathetic marker) was used to reveal the graft microstructure, vasculature, and sympathetic innervation. Three weeks after transplantation, we observed perigraft sympathetic innervation similar to the peri-islet sympathetic innervation in the pancreas. Six weeks after transplantation, prominent intragraft, perivascular sympathetic innervation was achieved, resembling the pancreatic intraislet, perivascular sympathetic innervation in situ. Meanwhile, in diabetic recipients, a higher graft sympathetic nerve density was found compared with grafts in normoglycemic recipients, indicating the graft neural plasticity in response to the physiological difference of the recipients and the resolving power of this imaging approach. Overall, this new graft imaging method provides a useful tool to identify the islet neurovascular complex in an ectopic environment to study islet engraftment.
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Trasplante de Islotes Pancreáticos/fisiología , Islotes Pancreáticos/inervación , Riñón/inervación , Plasticidad Neuronal/fisiología , Sistema Nervioso Simpático/fisiología , Animales , Glucagón/metabolismo , Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Riñón/metabolismo , RatonesRESUMEN
Recently, we successfully utilized noninvasive magnetic resonance and bioluminescence imaging to track MIN6 cells subcutaneously transplanted in immunocompromised nude mice for up to 64 days. In this study, we further used bioluminescence imaging to investigate the immune rejection of MIN6 cells in immunocompetent C3H mice. A total of 5 × 106 luciferase-transfected MIN6 cells were implanted into the subcutaneous space of each nude or C3H mouse. After transplantation, hypoglycemia and persistent bioluminescence signals were observed in eight of eight (100%) nude mice and five of nine (56%) C3H mice (p < 0.05). We then presensitized a group of C3H mice with C57BL/6 spleen cells just prior to transplantation (n = 14). Interestingly, none of them had hypoglycemia or persistent bioluminescence signals (p < 0.01 vs. C3H mice without presensitization). Histological examination of the grafts revealed a lack or minimal presence of insulin-positive cells in recipients without hypoglycemia and persistent bioluminescence signals. In contrast, recipients with hypoglycemia and persistent bioluminescence signals showed a significant presence of insulin-positive cells in their grafts. Our results indicate that rejection of MIN6 cells occurred in C3H mice and could be enhanced by presensitization with C57BL/6 spleen cells and that bioluminescence imaging is a useful noninvasive tool for detecting rejection of subcutaneously transplanted MIN6 cells.
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Rechazo de Injerto , Mediciones Luminiscentes , Ratones Endogámicos C3H , Animales , Ratones , Rechazo de Injerto/inmunología , Mediciones Luminiscentes/métodos , Ratones Endogámicos C57BL , Ratones Desnudos , Línea Celular Tumoral , BazoRESUMEN
Previously, we have successfully used noninvasive magnetic resonance (MR) and bioluminescence imaging to detect and monitor mPEG-poly(Ala) hydrogel-embedded MIN6 cells at the subcutaneous space for up to 64 days. In this study, we further explored the histological evolution of MIN6 cell grafts and correlated it with image findings. MIN6 cells were incubated overnight with chitosan-coated superparamagnetic iron oxide (CSPIO) and then 5 × 106 cells in the 100 µL hydrogel solution were injected subcutaneously into each nude mouse. Grafts were removed and examined the vascularization, cell growth and proliferation with anti-CD31, SMA, insulin and ki67 antibodies, respectively, at 8, 14, 21, 29 and 36 days after transplantation. All grafts were well-vascularized with prominent CD31 and SMA staining at all time points. Interestingly, insulin-positive cells and iron-positive cells were scattered in the graft at 8 and 14 days; while clusters of insulin-positive cells without iron-positive cells appeared in the grafts at 21 days and persisted thereafter, indicating neogrowth of MIN6 cells. Moreover, proliferating MIN6 cells with strong ki67 staining was observed in 21-, 29- and 36-day grafts. Our results indicate that the originally transplanted MIN6 cells proliferated from 21 days that presented distinctive bioluminescence and MR images.
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Recently, we have shown that manganese magnetism-engineered iron oxide nanoparticles (MnMEIO NPs) conjugated with exendin-4 (Ex4) act as a contrast agent that directly trace implanted mouse islet ß-cells by magnetic resonance imaging (MRI). Here we further advanced this technology to track implanted porcine neonatal pancreatic cell clusters (NPCCs) containing ducts, endocrine, and exocrine cells. NPCCs from one-day-old neonatal pigs were isolated, cultured for three days, and then incubated overnight with MnMEIO-Ex4 NPs. Binding of NPCCs and MnMEIO-Ex4 NPs was confirmed with Prussian blue staining in vitro prior to the transplantation of 2000 MnMEIO-Ex4 NP-labeled NPCCs beneath the left renal capsule of six nondiabetic nude mice. The 7.0 T MRI on recipients revealed persistent hypointense areas at implantation sites for up to 54 days. The MR signal intensity of the graft on left kidney reduced 62-88% compared to the mirror areas on the contralateral kidney. Histological studies showed colocalization of insulin/iron and SOX9/iron staining in NPCC grafts, indicating that MnMEIO-Ex4 NPs were taken up by mature ß-cells and pancreatic progenitors. We conclude that MnMEIO-Ex4 NPs are excellent contrast agents for detecting and long-term monitoring implanted NPCCs by MRI.
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AIMS: To examine the impact of the threat of hypoglycaemic episodes on people with diabetes in Taiwan. BACKGROUND: Intensive diabetes treatment in people with diabetes helps them to achieve better glycaemic control. However, it also causes more frequent hypoglycaemic episodes and has an impact on their overall quality of life. Hypoglycaemia is accompanied by various distressing symptoms which may cause excessive fear, affecting decision making in hypoglycaemic management. DESIGN: Purposive sampling and in-depth, face-to-face interviews were used to collect data. METHODS: Semi-structured interviews were conducted from July 2008-January 2009 with 17 individuals treated with insulin who had previous hypoglycaemic episodes. Data were analysed using qualitative content analysis. RESULTS: Four themes were generated from the analysis, 'inability to control fluctuations in health', 'challenges to interpersonal relationships', 'facing the disease alone' and 'finding a balance between competing symptoms'. CONCLUSIONS: Hypoglycaemia is a major health issue for many people with diabetes. Understanding individuals' experiences with hypoglycaemic episodes should help practitioners become more fully involved in promoting self-management. We identified key areas that health care providers should address, including concerns about patient education and professional support for people with diabetes experiencing hypoglycaemia, to enhance problem solving skills for them and their families. RELEVANCE TO CLINICAL PRACTICE: We recommend that health care providers make proper use of support groups for family caregivers or other important individuals in the lives of people with diabetes to provide education, clarification, support and guidance. In addition, health care providers also need to provide clients with hypoglycaemia-related emotional support, while enhancing diabetes self-management and problem-solving skills.
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Diabetes Mellitus/fisiopatología , Hipoglucemia/complicaciones , Femenino , Humanos , Hipoglucemia/fisiopatología , Entrevistas como Asunto , Masculino , Calidad de Vida , TaiwánRESUMEN
The purpose of this study was to evaluate the effects of a hypoglycemia problem-solving program (HPSP) on problem-solving ability and glycemic control in diabetics with hypoglycemia. This was a prospective, quasi-experimental study with two groups, using a pre- and post-repeated measures design. A total of 71 diabetic patients with hypoglycemia were purposively assigned to an experimental group (n = 34) and a control group (n = 37). The experimental group participated in an 8-week HPSP, and each weekly session lasted approximately 90 min, while the control group received usual care. Participants were assessed at baseline, 1, 3, and 6 months after intervention care. In the experimental group, 6 months after the HPSP intervention, HbA1c was superior to that before the intervention. In both groups, the score obtained using the hypoglycemia problem-solving scale (HPSS) was low before the intervention. In the experimental group, HPSS tracking improved at all stages after the intervention compared to before the intervention. In the control group, the HPSS score improved slightly in the first month and sixth months after usual care. There were significant differences between and within groups in HbA1c levels and HPSS score over time. The intervention based on the HPSP effectively improves HbA1c level and hypoglycemia problem-solving ability in patients with hypoglycemia.
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Diabetes Mellitus , Hipoglucemia , Hemoglobina Glucada/análisis , Control Glucémico , Humanos , Hipoglucemia/prevención & control , Solución de Problemas , Estudios ProspectivosRESUMEN
BACKGROUND: Previous studies showed inconsistent Results of the effects of dipeptidyl peptidase (DPP)-IV inhibitors on syngeneic mouse islet transplantation. We hypothesized that the implanted islet numbers are critical for the effects of DPP-IV inhibitors on the outcomes of transplantation. METHODS: One hundred and fifty or three hundred islets were syngeneically transplanted under the renal capsule of each streptozocin-diabetic C57BL/6 mouse and recipients were then treated without or with LAF237 (10 mg/kg/day, po) for 6 weeks. After transplantation, recipients' blood glucose, body weight and intraperitoneal glucose tolerance test (IPGTT) were followed-up periodically. The graft was removed for the measurement of ß-cell mass at 6 weeks. RESULTS: In recipients with 150 islets, it was not significantly different between the LAF237- treated group (n = 14) and control group (n = 14) in terms of the blood glucose, body weight, glucose tolerance at 2, 4 and 6 weeks or the graft ß-cell mass at 6 weeks. In contrast, in recipients with 300 islets, the LAF237-treated group (n = 24) did have a lower area under the curve of the IPGTT at 4 weeks (p = 0.0237) and 6 weeks (p = 0.0113) as well as more graft ß-cell mass at 6 weeks (0.655 ± 0.008 mg vs. 0.435 ± 0.006 mg, p = 0.0463) than controls (n = 24). CONCLUSIONS: Our findings revealed 6-week treatment of LAF237 improves glucose tolerance and increases graft ß-cell mass in diabetic mice transplanted with a sufficient number but not a marginal number of islets. These indicate that the effects of DPP-IV inhibitors are influenced by the implanted islet mass.
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Diabetes Mellitus Experimental , Inhibidores de la Dipeptidil-Peptidasa IV , Adamantano/análogos & derivados , Animales , Glucemia , Peso Corporal , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/cirugía , Inhibidores de la Dipeptidil-Peptidasa IV/farmacología , Inhibidores de la Dipeptidil-Peptidasa IV/uso terapéutico , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas , Humanos , Hipoglucemiantes/farmacología , Ratones , Ratones Endogámicos C57BL , PirrolidinasRESUMEN
Neonatal pancreatic cell clusters (NPCCs) are potential tissues for the treatment of diabetes. Different from adult cells, they continuously proliferate and differentiate after transplantation. In this study, we utilized magnetic resonance imaging (MRI) to detect and monitor implanted NPCCs. NPCCs were isolated from one-day-old neonatal pigs, cultured for three days, and then incubated overnight with the contrast agent chitosan-coated superparamagnetic iron oxide (CSPIO) nanoparticles. In vitro, Prussian blue staining and MR scans of CSPIO-labeled NPCCs were performed. In vivo, we transplanted 2000 CSPIO-labeled NPCCs under the kidney capsule of nondiabetic nude mice. Recipients were scanned with 7.0T MRI. Grafts were removed for histology with insulin and Prussian blue staining. After being incubated overnight with CSPIO, NPCCs showed positive iron staining and appeared as dark spots on MR scans. After transplantation of CSPIO-labeled NPCCs, persistent hypointense areas were observed at recipients' implant sites for up to 54 days. Moreover, histology showed colocalization of the insulin and iron staining in 15-, 51- and 55-day NPCC grafts. Our results indicate that transplanted NPCCs survived and differentiated to ß cells after transplantation, and that MRI is a useful tool for the detection and monitoring of CSPIO-labeled NPCC grafts.
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To specifically detect and trace transplanted islet ß-cells by magnetic resonance imaging (MRI), we conjugated manganese magnetism-engineered iron oxide nanoparticles (MnMEIO NPs) with exendin-4 (Ex4) which specifically binds glucagon-like peptide-1 receptors on the surface of ß-cells. The size distribution of MnMEIO and MnMEIO-Ex4 NPs were 67.8 ± 1.3 and 70.2 ± 2.3 nm and zeta potential 33.3 ± 0.5 and 0.6 ± 0.1 mV, respectively. MnMEIO and MnMEIO-Ex4 NPs with iron content ≤ 40 µg/mL did not affect MIN6 ß-cell viability and insulin secretion. Positive iron staining was found in MIN6 ß-cells loaded with MnMEIO-Ex4 NPs but not in those with MnMEIO NPs. A transmission electron microscope confirmed MnMEIO-Ex4 NPs were distributed in the cytoplasm of MIN6. In vitro MR images revealed a loss of signal intensity in MIN6 ß-cells labeled with MnMEIO-Ex4 NPs but not with MnMEIO NPs. After transplantation of islets labeled with MnMEIO-Ex4, the graft under kidney capsule could be visualized on MRI as persistent hypointense areas up to 17 weeks. Moreover, histology of the islet graft showed positive staining for insulin, glucagon and iron. Our results indicate MnMEIO-Ex4 NPs are safe and effective for the detection and long-term monitoring of transplanted ß-cells by MRI.
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Recently, we demonstrated the feasibility of subcutaneous transplantation of MIN6 cells embedded in a scaffold with poly(ethylene glycol) methyl ether (mPEG)-poly(Ala) hydrogels. In this study, we further tracked these grafts using magnetic resonance (MR) and bioluminescence imaging. After being incubated overnight with chitosan-coated superparamagnetic iron oxide (CSPIO) nanoparticles and then mixed with mPEG-poly(Ala) hydrogels, MIN6 cells appeared as dark spots on MR scans. For in vivo experiments, we transfected MIN6 cells with luciferase and/or incubated them overnight with CSPIO overnight; 5 × 106 MIN6 cells embedded in mPEG-poly(Ala) hydrogels were transplanted into the subcutaneous space of each nude mouse. The graft of CSPIO-labeled MIN6 cells was visualized as a distinct hypointense area on MR images located at the implantation site before day 21. However, this area became hyperintense on MR scans for up to 64 days. In addition, positive bioluminescence images were also observed for up to 64 days after transplantation. The histology of removed grafts showed positive insulin and iron staining. These results indicate mPEG-poly(Ala) is a suitable scaffold for ß-cell encapsulation and transplantation. Moreover, MR and bioluminescence imaging are useful noninvasive tools for detecting and monitoring mPEG-poly(Ala) hydrogel-embedded MIN6 cells at a subcutaneous site.
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Decoy receptor 3 (DCR3) halts both Fas ligand- and LIGHT-induced cell deaths, which are required for pancreatic beta cell damage in autoimmune diabetes. To directly investigate the therapeutic potential of DCR3 in preventing this disease, we generated transgenic nonobese diabetic mice, which overexpressed DCR3 in beta cells. Transgenic DCR3 protected mice from autoimmune and cyclophosphamide-induced diabetes in a dose-dependent manner and significantly reduced the severity of insulitis. Local expression of the transgene did not alter the diabetogenic properties of systemic lymphocytes or the development of T helper 1 or T regulatory cells. The transgenic islets had a higher transplantation success rate and survived for longer than wild-type islets. We have demonstrated for the first time that the immune-evasion function of DCR3 inhibits autoimmunity and that genetic manipulation of grafts may improve the success and survival of islet transplants.
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Diabetes Mellitus Tipo 1/inmunología , Islotes Pancreáticos/inmunología , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/fisiología , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/fisiología , Animales , Secuencia de Bases , Cartilla de ADN/genética , Diabetes Mellitus Tipo 1/patología , Diabetes Mellitus Tipo 1/prevención & control , Femenino , Expresión Génica , Supervivencia de Injerto , Islotes Pancreáticos/patología , Trasplante de Islotes Pancreáticos , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Ratones Transgénicos , Receptores del Factor de Necrosis Tumoral , Miembro 6b de Receptores del Factor de Necrosis Tumoral , Células TH1/inmunología , Células Th2/inmunologíaRESUMEN
Islet transplantation has been demonstrated to be a promising therapy for type 1 diabetes mellitus. Although it is a minimally invasive operating procedure and provides easy access for graft monitoring, subcutaneous transplantation of the islet only has limited therapeutic outcomes, owing to the poor capacity of skin tissue to foster revascularization in a short period. Herein, 3D cell spheroids of clinically accessible umbilical cord blood mesenchymal stem cells and human umbilical vein endothelial cells are formed and employed for codelivery with ß cells subcutaneously. The 3D stem cell spheroids, which can secrete multiple proangiogenic and prosurvival growth factors, induce robust angiogenesis and prevent ß cell graft death, as indicated by the results of in vivo bioluminescent tracking and histological analysis. These experimental data highlight the efficacy of the 3D stem cell spheroids that are fabricated using translationally applicable cell types in promoting the survival and function of subcutaneously transplanted ß cells.
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Supervivencia Celular/fisiología , Células Secretoras de Insulina , Neovascularización Fisiológica/fisiología , Esferoides Celulares , Animales , Células Cultivadas , Células Endoteliales de la Vena Umbilical Humana/citología , Células Endoteliales de la Vena Umbilical Humana/trasplante , Humanos , Células Secretoras de Insulina/fisiología , Células Secretoras de Insulina/trasplante , Células Madre Mesenquimatosas/citología , Ratones , Ratones Desnudos , Esferoides Celulares/citología , Esferoides Celulares/trasplanteRESUMEN
More than half of diabetic wounds demonstrate clinical signs of infection at presentation and lead to poor outcomes. This work develops coaxial sheath-core nanofibrous poly(lactide-co-glycolide) (PLGA) scaffolds that are loaded with bioactive antibiotics and platelet-derived growth factor (PDGF) for the repair of diabetic infectious wounds. PDGF and PLGA/antibiotic solutions were pumped, respectively, into two independent capillary tubings for coaxial electrospinning to prepare biodegradable sheath-core nanofibers. Spun nanofibrous scaffolds sustainably released PDGF, vancomycin, and gentamicin for 3 weeks. The scaffolds also reduced the phosphatase and tensin homologue content, enhanced the amount of angiogenesis marker (CD31) around the wound area, and accelerated healing in the early stage of infected diabetic wound repair. Antibiotic/biomolecule-loaded PLGA nanofibers may provide a very effective way to aid tissue regeneration at the sites of infected diabetic wounds.
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Diabetes Mellitus , Nanofibras , Antibacterianos , Humanos , Factor de Crecimiento Derivado de Plaquetas , VancomicinaRESUMEN
BACKGROUND: The high lifetime risk of vascular disease is one of the important issues that plague patients with diabetes mellitus. Systemic oral vildagliptin administration favors endothelial recovery and inhibits smooth muscle cell (SMC) proliferation. However, the localized release of vildagliptin in the diabetic vessel damage has seldom been investigated. RESEARCH DESIGN AND METHODS: In this work, nanofiber-eluting stents that loaded with vildagliptin, a dipeptidyl peptidase-4 enzyme (DPP-4) inhibitor, was fabricated to treat diabetic vascular disease. To prepare nanofibers, the poly (D,L)-lactide-co-glycolide (PLGA) and vildagliptin were mixed using hexafluoroisopropanol and electrospinning process. In vitro and in vivo release rates of the vildagliptin were characterized using high-performance liquid chromatography. RESULTS: Effective vildagliptin concentrations were delivered for more than 28 days from the nanofibrous membranes coating on the surface of the stents in vitro and in vivo. The vildagliptin-eluting PLGA membranes greatly accelerated the recovery of diabetic endothelia and reduced SMC hyperplasia. The type I collagen content of the diabetic vascular intimal area that was treated by vildagliptin-eluting stents was lower than that of the non-vildagliptin-eluting group. CONCLUSION: The experimental results revealed that stenting with vildagliptin-eluting PLGA membranes could potentially promote healing for diabetic arterial diseases.
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Diabetes Mellitus/tratamiento farmacológico , Stents Liberadores de Fármacos , Endotelio/patología , Nanofibras/química , Neointima/tratamiento farmacológico , Vildagliptina/uso terapéutico , Animales , Aorta/efectos de los fármacos , Aorta/patología , Colágeno Tipo I/metabolismo , Endotelio/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Humanos , Masculino , Nanofibras/ultraestructura , Conejos , Vildagliptina/farmacologíaRESUMEN
In the study, chitosan (CS) was conjugated with trimethyl groups for the synthesis of N-trimethyl chitosan (TMC) polymers with different degrees of quaternization. Nanoparticles (NPs) self-assembled by the synthesized TMC and poly(gamma-glutamic acid) (gamma-PGA, TMC/gamma-PGA NPs) were prepared for oral delivery of insulin. The loading efficiency and loading content of insulin in TMC/gamma-PGA NPs were 73.8 +/- 2.9% and 23.5 +/- 2.1%, respectively. TMC/gamma-PGA NPs had superior stability in a broader pH range to CS/gamma-PGA NPs; the in vitro release profiles of insulin from both test NPs were significantly affected by their stability at distinct pH environments. At pH 7.0, CS/gamma-PGA NPs became disintegrated, resulting in a rapid release of insulin, which failed to provide an adequate retention of loaded insulin, while the cumulative amount of insulin released from TMC/gamma-PGA NPs was significantly reduced. At pH 7.4, TMC/gamma-PGA NPs were significantly swelled and a sustained release profile of insulin was observed. Confocal microscopy confirmed that TMC40/gamma-PGA NPs opened the tight junctions of Caco-2 cells to allow the transport of insulin along the paracellular pathway. Transepithelial-electrical-resistance measurements and transport studies implied that CS/gamma-PGA NPs can be effective as an insulin carrier only in a limited area of the intestinal lumen where the pH values are close to the p K a of CS. In contrast, TMC40/gamma-PGA NPs may be a suitable carrier for transmucosal delivery of insulin within the entire intestinal tract.
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Quitosano/química , Portadores de Fármacos/química , Insulina/química , Insulina/farmacología , Nanopartículas/química , Ácido Poliglutámico/análogos & derivados , Polímeros/química , Administración Oral , Animales , Células CACO-2 , Portadores de Fármacos/síntesis química , Impedancia Eléctrica , Ensayo de Inmunoadsorción Enzimática , Células Epiteliales/metabolismo , Humanos , Concentración de Iones de Hidrógeno , Insulina/administración & dosificación , Metilación , Modelos Moleculares , Conformación Molecular , Ácido Poliglutámico/química , Polímeros/síntesis química , SolubilidadRESUMEN
Exendin-4 stimulates insulin secretion, suppresses glucagons secretion, increases beta-cell replication and neogenesis, and reduces beta-cell apoptosis. However, it has been shown that posttransplant exendin-4 treatment did not improve glucose homeostasis in diabetic mice transplanted with a large number of freshly isolated islets. The aim of this study was to test if exendin-4 is beneficial for hyperglycemic recipients with a marginal number of fresh islets. We transplanted 150 C57BL/6 mouse islets under the kidney capsule of inbred streptozotocin-diabetic mice, and then treated the recipients with and without exendin-4 for 6 weeks. Before and after transplantation, recipients' blood glucose, body weight, and intraperitoneal glucose tolerance test were measured. At 6 weeks, the grafts were removed to determine beta-cell mass. Blood glucose levels in both groups decreased progressively after transplantation, and the exendin-4-treated group had had lower blood glucose than controls since day 3. By 6 weeks, euglycemia was achieved more in mice treated with exendin-4 than in controls (100% vs. 62.5%, p = 0.018). The time to obtain normoglycemia was shorter in the exendin-4-treated group than in controls (12 +/- 8 vs. 29 +/- 13 days, p < 0.001). Blood glucose at 6 weeks was 123 +/- 18 and 170 +/- 62 mg/dl in the exendin-4-treated group and controls, respectively (p = 0.008). Additionally, the exendin-4-treated group had better glucose tolerance than controls at 2 and 4 weeks (p <0.02). However, both groups exhibited increased body weight over time, and weight changes did not significantly differ between the two groups throughout the study period. At 6 weeks after transplantation, grafts in the exendin-4-treated group were more prominent and contained more insulin-stained cells than those of controls. They had 2.3-fold beta-cell mass of the graft compared with controls (0.30 +/- 0.11 vs. 0.13 +/- 0.03 mg, p = 0.012). These results indicate posttransplant exendin-4 treatment in the diabetic recipient with a marginal number of fresh islets expands graft beta-cell mass and improves transplantation outcome.
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Hipoglucemiantes/uso terapéutico , Células Secretoras de Insulina , Trasplante de Islotes Pancreáticos , Péptidos/uso terapéutico , Ponzoñas/uso terapéutico , Animales , Glucemia/metabolismo , Diabetes Mellitus Experimental/terapia , Exenatida , Humanos , Hipoglucemiantes/farmacología , Células Secretoras de Insulina/citología , Células Secretoras de Insulina/efectos de los fármacos , Estimación de Kaplan-Meier , Masculino , Ratones , Ratones Endogámicos C57BL , Péptidos/farmacología , Estreptozocina , Trasplante Homólogo , Ponzoñas/farmacologíaRESUMEN
BACKGROUND: Hypoglycemia is recognized as a limiting factor in diabetes management. Fear of experiencing hypoglycemia may lead to lower quality of life, impaired glycemic control, and emotional distress, all of which impair the ability of patients to self-manage their diabetes effectively. Problem solving is central to diabetes self-management and may help patients achieve effective self-care of their disease. PURPOSE: The aim of this study was to investigate the ability of people with diabetes to avoid hypoglycemia and to explore associated factors. METHODS: A cross-sectional, descriptive design was used for the study. Data were collected using a demographic and disease characteristics datasheet, the Hypoglycemic Problem Solving Scale, and the Disease-Associated Negative Mood Scale. RESULTS: Three hundred thirteen participants were recruited, with a mean age of 55.49 years. The average item score for the questions on hypoglycemic problem-solving ability was 2.43 (SD = 0.75). In comparing Hypoglycemic Problem Solving Scale subscales, participants scored highest on the problem orientation subscales and lowest on the problem-solving skills subscales. Multiple regression analysis revealed that being younger and unmarried and having a higher level of education, a diagnosis of Type 1 diabetes, and a lower negative mood score were each significantly associated with greater problem-solving ability as regards hypoglycemic events. CONCLUSIONS/IMPLICATIONS FOR PRACTICE: We suggest that patients with diabetes, especially those who are older or with lower levels of education, receive disease-related psychological interventions and that healthcare professionals teach problem-solving abilities in conjunction with hypoglycemia management.
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Diabetes Mellitus/terapia , Hipoglucemia/prevención & control , Autocuidado/psicología , Adulto , Anciano , Estudios Transversales , Femenino , Humanos , Hipoglucemia/psicología , Masculino , Persona de Mediana Edad , Solución de Problemas , Factores de Riesgo , Factores SocioeconómicosRESUMEN
Efficient nonviral oral gene delivery offers an attractive modality for chronic protein replacement therapy. Herein, the oral delivery of insulin gene is reported by a nonviral vector comprising a copolymer with a high degree of substitution of branched polyethylenimine on chitosan (CS-g-bPEI). Protecting the plasmid from gastric acidic degradation and facilitating transport across the gut epithelium, the CS-g-bPEI/insulin plasmid DNA nanoparticles (NPs) can achieve systemic transgene expression for days. A single dose of orally administered NPs (600 µg plasmid insulin (pINS)) to diabetic mice can protect the animals from hyperglycemia for more than 10 d. Three repeated administrations spaced over a 10 d interval produce similar glucose-lowering results with no hepatotoxicity detected. Positron-emission-tomography and computed-tomography images also confirm the glucose utilization by muscle cells. While this work suggests the feasibility of basal therapy for diabetes mellitus, its significance lies in the demonstration of a nonviral oral gene delivery system that can impact chronic protein replacement therapy and DNA vaccination.