Direct Differentiation of Bone Marrow Mononucleated Cells Into Insulin-Producing Cells Using 4 Specific Soluble Factors.

Bone marrow-derived stem cells are self-renewing and multipotent adult stem cells that differentiate into several types of cells. Here, we investigated a unique combination of 4 differentiation-inducing factors (DIFs), including putrescine (Put), glucosamine (GlcN), nicotinamide, and BP-1-102, to develop a differentiation method for inducing mature insulin-producing cells (IPCs) and apply this method to bone marrow mononucleated cells (BMNCs) isolated from mice. BMNCs, primed with the 4 soluble DIFs, were differentiated into functional IPCs. BMNCs cultured under the defined conditions synergistically expressed multiple genes, including those for PDX1, NKX6.1, MAFA, NEUROG3, GLUT2, and insulin, related to pancreatic beta cell development and function. They produced insulin/C-peptide and PDX1, as assessed using immunofluorescence and flow cytometry. The induced cells secreted insulin in a glucose-responsive manner, similar to normal pancreatic beta cells. Grafting BMNC-derived IPCs under kidney capsules of mice with streptozotocin (STZ)-induced diabetes alleviated hyperglycemia by lowering blood glucose levels, enhancing glucose tolerance, and improving glucose-stimulated insulin secretion. Insulin- and PDX1-expressing cells were observed in the IPC-bearing graft sections of nephrectomized mice. Therefore, this study provides a simple protocol for BMNC differentiation, which can be a novel approach for cell-based therapy in diabetes mellitus.

Association between pancreatic fibrosis and development of pancreoprivic diabetes after pancreaticoduodenectomy.

This study investigated the correlation between pancreatic fibrosis (PF) and development of pancreoprivic diabetes after pancreaticoduodenectomy (PD). Ninety-five patients who underwent PD at Gangnam Severance Hospital between 2014 and 2017 were enrolled. PF grade was evaluated with alpha-smooth muscle actin (SMA) and Masson's trichrome (TRC) staining. New-onset pancreoprivic diabetes and recurrence of disease were evaluated using fasting blood glucose measurement and radiography taken at 3-month intervals. Sixty-one patients did not have preoperative diabetes, however, 40 (65.6%) patients developed pancreoprivic diabetes after PD. High-grade PF was more common in the diabetes group than in the normal group (SMA, 42.5% vs. 28.6%, P = 0.747; TRC, 47.5% vs. 28.6%, P = 0.361). The 1-year cumulative incidence of hyperglycemia/pancreoprivic diabetes was higher with high-grade PF than low-grade PF (SMA, 94.4% vs. 73.0%, P = 0.027; TRC, 89.3% vs. 75.0%, P = 0.074). The SMA-TRC combined high-grade group had a higher proportion of primary pancreatic disease than the combined low-grade group (90.0% vs. 37.5%, P = 0.001). The 5-year disease-free survival of patients with pancreatic cancer was worse with high-grade PF than low-grade PF (SMA, 24.5% vs. 66.3%, P = 0.026; TRC, 23.6% vs. 58.4%, P = 0.047). In conclusion, patients with severe PF are more likely to develop pancreoprivic diabetes after PD and have worse disease-free survival.

Significance of Soluble CD93 in Type 2 Diabetes as a Biomarker for Diabetic Nephropathy: Integrated Results from Human and Rodent Studies.

Cluster of differentiation 93 (CD93) is a glycoprotein expressed in activated endothelial cells. The extracellular portion of CD93 can be secreted as a soluble form (sCD93) under inflammatory conditions. As diabetic nephropathy (DN) is a well-known inflammatory disease, we hypothesized that sCD93 would be a new biomarker for DN. We prospectively enrolled 97 patients with type 2 diabetes and evaluated the association between serum sCD93 and DN prevalence. The association between CD93 and development of DN was investigated using human umbilical cord endothelial cells (HUVECs) in vitro and diabetic db/db mice in vivo. Subjects with higher sCD93 levels had a lower estimated glomerular filtration rate (eGFR). The sCD93 level was an independent determinant of both the albumin-to-creatinine ratio (ACR) and the eGFR. The risk of prevalent DN was higher in the high sCD93 group (adjusted odds ratio 7.212, 95% confidence interval 1.244-41.796, p = 0.028). In vitro, CD93 was highly expressed in HUVECs and both CD93 expression and secretion were upregulated after lipopolysaccharides (LPS) stimulation. In vivo, peritoneal and urine sCD93 levels and the renal glomerular expression of CD93 were significantly higher in the db/db mice than in the control db/m+ mice. These results suggest the potential of sCD93 as a candidate biomarker associated with DN.

Direct differentiation of bone marrow mononucleated cells into insulin producing cells using pancreatic ß-cell-derived components.

Transplantation of stem cell-derived insulin producing cells (IPCs) has been proposed as an alternative to islet transplantation for the treatment of diabetes mellitus. However, current IPC differentiation protocols are focused on generating functional cells from the pluripotent stem cells and tend to rely on multistep, long-term exposure to various exogenous factors. In this study, we addressed the observation that under stress, pancreatic ß-cells release essential components that direct the differentiation of the bone marrow nucleated cells (BMNCs) into IPCs. Without any supplementation with known differentiation-inducing factors, IPCs can be generated from BMNCs by in vitro priming for 6 days with conditioned media (CM) from the ß-cells. In vitro primed BMNCs expressed the ß-cell-specific transcription factors, as well as insulin, and improved hyperglycemia and glucose intolerance after transplantation into the streptozotocin-induced diabetic mice. Furthermore, we have found that components of the CM which trigger the differentiation were enclosed by or integrated into micro particles (MPs), rather than being secreted as soluble factors. Identification of these differentiation-directing factors might enable us to develop novel technologies required for the production of clinically applicable IPCs.

ß-Cell-Derived Angiopoietin-1 Regulates Insulin Secretion and Glucose Homeostasis by Stabilizing the Islet Microenvironment.

Islets are highly vascularized for prompt insulin secretion. Although angiopoietin-1 (Ang1) is a well-known angiogenic factor, its role in glucose homeostasis remains largely unknown. The objective of this study was to investigate whether and how Ang1 contributes to glucose homeostasis in response to metabolic challenge. We used inducible systemic Ang1 knockout (Ang1sys-/-) and ß-cell-specific Ang1 knockout (Ang1ß-cell-/-) mice fed a high-fat diet for 24 weeks. Although the degree of insulin sensitivity did not differ between Ang1sys-/- and Ang1sys+/+ mice, serum insulin levels were lower in Ang1sys-/- mice, resulting in significant glucose intolerance. Similar results were observed in Ang1ß-cell-/- mice, suggesting a critical role of ß-cell-derived Ang1 in glucose homeostasis. There were no differences in ß-cell area or vasculature density, but glucose-stimulated insulin secretion was significantly decreased, and PDX-1 expression and GLUT2 localization were altered in Ang1ß-cell-/- compared with Ang1ß-cell+/+ mice. These effects were associated with less pericyte coverage, disorganized endothelial cell ultrastructure, and enhanced infiltration of inflammatory cells and upregulation of adhesion molecules in the islets of Ang1ß-cell-/- mice. In conclusion, ß-cell-derived Ang1 regulates insulin secretion and glucose homeostasis by stabilizing the blood vessels in the islet and may be a novel therapeutic target for diabetes treatment in the future.

Noninvasive Imaging of Myocardial Inflammation in Myocarditis using 68Ga-tagged Mannosylated Human Serum Albumin Positron Emission Tomography.

The diagnosis of myocarditis traditionally relies on invasive endomyocardial biopsy but none of the imaging studies so far are specific for infiltration of the inflammatory cells itself. We synthesized 68Ga-2-(p-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) mannosylated human serum albumin (MSA) by conjugating human serum albumin with mannose, followed by conjugation with NOTA and labeling it with 68Ga. The efficacy of 68Ga-NOTA-MSA positron emission tomography (PET) for imaging myocardial inflammation was tested in a rat myocarditis model. A significant number of mannose receptor-positive inflammatory cells infiltrated the myocardium in both human and rat myocarditis tissue. 68Ga-NOTA-MSA uptake was upregulated in organs of macrophage accumulation, such as liver, spleen, bone marrow and myocardium (0.32 (0.31~0.33) for normal versus 1.02 (0.86~1.06) for myocarditis (median (range), SUV); n=4~6 per group, p-value=0.01). 68Ga-NOTA-MSA uptake in the left ventricle was upregulated in myocarditis compared with normal rats (2.29 (1.42~3.40) for normal versus 4.18 (3.43~6.15) for myocarditis (median (range), average standard uptake value ratio against paraspinal muscle); n=6 per group, p-value<0.01), which was downregulated in rats with cyclosporine-A treated myocarditis (3.69 (2.59~3.86) for myocarditis versus 2.28 (1.76~2.60) for cyclosporine-A treated myocarditis; n=6 per group, p-value<0.01). The specificity of the tracer was verified by administration of excess non-labeled MSA. 68Ga-NOTA-MSA uptake was significantly enhanced earlier in the evolution of myocarditis before any signs of inflammation could be seen on echocardiography. These results demonstrate the potential utility of visualizing infiltration of mannose receptor-positive macrophages with 68Ga-NOTA-MSA PET in the early diagnosis of as well as in the monitoring of treatment response of myocarditis.

Attenuation of carotid neointimal formation after direct delivery of a recombinant adenovirus expressing glucagon-like peptide-1 in diabetic rats.

AIMS: Enhancement of glucagon-like peptide-1 (GLP-1) reduces glucose levels and preserves pancreatic ß-cell function, but its effect against restenosis is unknown. METHODS AND RESULTS: We investigated the effect of subcutaneous injection of exenatide or local delivery of a recombinant adenovirus expressing GLP-1 (rAd-GLP-1) into carotid artery, in reducing the occurrence of restenosis following balloon injury. As a control, we inserted ß-galactosidase cDNA in the same vector (rAd-ßGAL). Otsuka Long-Evans Tokushima rats were assigned to three groups (n = 12 each): (1) normal saline plus rAd-ßGAL delivery (NS + rAd-ßGAL), (2) exenatide plus rAd-ßGAL delivery (Exenatide + rAd-ßGAL), and (3) normal saline plus rAd-GLP-1 delivery (NS + rAd-GLP-1). Normal saline or exenatide were administered subcutaneously from 1 week before to 2 weeks after carotid injury. After 3 weeks, the NS + rAd-ßGAL group showed the highest intima-media ratio (IMR; 3.73 ± 0.90), the exenatide + rAd-ßGAL treatment was the next highest (2.80 ± 0.51), and NS + rAd-GLP-1 treatment showed the lowest IMR (1.58 ± 0.48, P < 0.05 vs. others). The proliferation and migration of vascular smooth muscle cells and monocyte adhesion were decreased significantly after rAd-GLP-1 treatment, showing the same overall patterns as the IMR. In injured vessels, the apoptosis was greater and MMP2 expression was less in the NS + rAd-GLP-1 than in the exenatide or rAd-ßGAL groups. In vitro expressions of matrix metalloproteinases-2 and monocyte chemoattractant protein-1 and nuclear factor-kappa-B-p65 translocation were decreased more in the NS + rAd-GLP-1 group than in the other two groups (all P < 0.05). CONCLUSION: Direct GLP-1 overexpression showed better protection against restenosis after balloon injury via suppression of vascular smooth muscle cell migration, increased apoptosis, and decreased inflammatory processes than systemic exenatide treatment. This has potential therapeutic implications for treating macrovascular complications in diabetes.

Senp2 expression was induced by chronic glucose stimulation in INS1 cells, and it was required for the associated induction of Ccnd1 and Mafa.

Post-translational modification by bonding of small ubiquitin-like modifier (SUMO) peptides influences various cellular functions, and is regulated by SUMO-specific proteases (SENPs). Several proteins have been suggested to have diverse impact on insulin synthesis and secretion through SUMO modification in ß cells. However, the role of SUMO modification in ß cell mass has not been established. Here, we examined the changes in expression of Senp in INS1 cells and pancreatic islets under diabetes-relevant stress conditions and associated changes in ß cell mass. Treatment with 25 mM glucose for 72 h induced Senp2 mRNA expression but not that of Senp1 in INS1 cells. Immunohistochemical staining with anti-SENP2 antibody on human pancreas sections revealed that SENP2 was localized in the nucleus. Moreover, in a patient with type 2 diabetes, SENP2 levels were enhanced, especially in the cytoplasm. Senp2 cytoplasmic levels were also increased in islet cells in obese diabetic mice. Cell number peaked earlier in INS1 cells cultured in high-glucose conditions compared to those cultured in control media. This finding was associated with increased Ccnd1 mRNA expression in high-glucose conditions, and siRNA-mediated Senp2 suppression abrogated it. Mafa expression, unlike Pdx1, was also dependent on Senp2 expression during high-glucose conditions. In conclusion, Senp2 may play a role in ß cell mass in response to chronic high-glucose through Cyclin D1 and Mafa.

BNIP3 is essential for mitochondrial bioenergetics during adipocyte remodelling in mice.

AIMS/HYPOTHESIS: Adipose tissue is a highly versatile system in which mitochondria in adipocytes undergo significant changes during active tissue remodelling. BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) is a mitochondrial protein and a known mitochondrial quality regulator. In this study, we investigated the role of BNIP3 in adipocytes, specifically under conditions of peroxisome proliferator-activated receptor-γ (PPARγ)-induced adipose tissue remodelling. METHODS: The expression of BNIP3 was evaluated in 3T3-L1 adipocytes in vitro, C57BL/6 mice fed a high-fat diet and db/db mice in vivo. Mitochondrial bioenergetics was investigated in BNIP3-knockdown adipocytes after rosiglitazone treatment. A putative peroxisome proliferator hormone responsive element (PPRE) was characterised by promoter assay and electrophoretic mobility shift assay (EMSA). RESULTS: The protein BNIP3 was more abundant in brown adipose tissue than white adipose tissue. Furthermore, BNIP3 expression was upregulated by 3T3-L1 pre-adipocyte differentiation, starvation and rosiglitazone treatment. Conversely, BNIP3 expression in adipocytes decreased under various conditions associated with insulin resistance. This downregulation of BNIP3 was restored by rosiglitazone treatment. Knockdown of BNIP3 in adipocytes inhibited rosiglitazone-induced mitochondrial biogenesis and function, partially mediated by the 5' AMP-activated protein kinase (AMPK)-peroxisome proliferator-activated receptor γ, co-activator 1 α (PGC1α) signalling pathway. Rosiglitazone treatment increased the transcription level of Bnip3 in the reporter assay and the presence of the PPRE site in the Bnip3 promoter was demonstrated by EMSA. CONCLUSIONS/INTERPRETATION: The protein BNIP3 contributes to the improvement of mitochondrial bioenergetics that occurs on exposure to rosiglitazone. It may be a novel therapeutic target for restoring mitochondrial dysfunction under insulin-resistant conditions.

Synthesis and Characterization of Carbon Nanofibers on Transition Metal Catalysts by Chemical Vapor Deposition.

Carbon nanofibers were synthesized on transition metal (Fe, Co, Cu) catalysts by Chemical Vapor Deposition (CVD). The variations of thickness and surface of the fibers were investigated according to the concentration of the transition metal. In order to prepare the metal catalysts for synthesis, transition metal nitrate and copper nitrate at a weight ratio were dissolved in distilled water. The obtained catalyst precipitates were filtered and then dried for more than 24 hours at 110 degrees C. Carbon nanofibers were synthesized by using ethylene gas of carbon source by CVD after pulverization of the fully-dried catalyst precipitates. They were characterized by SEM, EDS, Raman, XRD, XPS and TG/DTA, and their specific surface area was measured by BET. The characteristics of the synthesized carbon nanofibers were greatly influenced by the concentration ratio of the metal catalysts. Especially, uniform carbon nanofibers grew when the concentration ratio of Fe and Cu was 7:3, and that of Co and Cu was 6:4. Carbon nanofibers synthesized under such concentration conditions had the best crystallizability, compared to carbon nanofibers synthesized with metal catalysts of different concentration ratios, and revealed high amorphicity as well as high specific surface area.

Effect of a new PPAR-gamma agonist, lobeglitazone, on neointimal formation after balloon injury in rats and the development of atherosclerosis.

OBJECTIVE: The ligand-activated transcription factor peroxisome proliferator-activated receptor gamma (PPARγ) is a key factor in adipogenesis, insulin sensitivity, and cell cycle regulation. Activated PPARγ might also have anti-inflammatory and antiatherogenic properties. We tested whether lobeglitazone, a new PPARγ agonist, might protect against atherosclerosis. METHODS: A rat model of balloon injury to the carotid artery, and high-fat, high-cholesterol diet-fed apolipoprotein E gene knockout (ApoE(-/-)) mice were studied. RESULTS: After the balloon injury, lobeglitazone treatment (0.3 and 0.9 mg/kg) caused a significant decrease in the intima-media ratio compared with control rats (2.2 ± 0.9, 1.8 ± 0.8, vs. 3.3 ± 1.2, P < 0.01). Consistent with this, in ApoE(-/-) mice fed a high-fat diet, lobeglitazone treatment (1, 3, and 10 mg/kg) for 8 weeks reduced atherosclerotic lesion sizes in the aorta compared with the control mice in a dose-dependent manner. Treatment of vascular smooth muscle cells with lobeglitazone inhibited proliferation and migration and blocked the cell cycle G0/G1 to S phase progression dose-dependently. In response to lobeglitazone, tumor necrosis factor alpha (TNFα)-induced monocyte-endothelial cell adhesion was decreased by downregulating the levels of adhesion molecules. TNFα-induced nuclear factor kappa-B (NF-κB) p65 translocation into the nucleus was also blocked in endothelial cells. Insulin resistance was decreased by lobeglitazone treatment. Circulating levels of high sensitivity C-reactive protein and monocyte chemoattractant protein-1 were decreased while adiponectin levels were increased by lobeglitazone in the high-fat diet-fed ApoE(-/-) mice. CONCLUSION: Lobeglitazone has antiatherosclerotic properties and has potential for treating patients with diabetes and cardiovascular risk.

Anti-diabetic efficacy of KICG1338, a novel glycogen synthase kinase-3ß inhibitor, and its molecular characterization in animal models of type 2 diabetes and insulin resistance.

Selective inhibition of glycogen synthase kinase-3 (GSK3) has been targeted as a novel therapeutic strategy for diabetes mellitus. We investigated the anti-diabetic efficacy and molecular mechanisms of KICG1338 (2-(4-fluoro-phenyl)-3H-imidazo[4,5-b]pyridine-7-carboxylic acid(4-methyl-pyridin-3-yl)-amide), a GSK3ß inhibitor, in three animal models: Otsuka Long-Evans Tokushima Fatty (OLETF) rats, leptin receptors-deficient db/db mice, and diet-induced obese (DIO) mice. Biochemical parameters including glucose tolerance tests and gene expressions associated with glucose metabolism were investigated. Glucose excursion decreased significantly by KICG1338-treated OLETF rats, accompanied by increase in insulin receptor substrate-1 and glucose transporter (GLUT)-4 expressions in muscle and decreased GLUT-2 expression in liver. Glucose-lowering effects were similarly observed in KICG1338-treated db/db and DIO mice. KICG1338 treatment increased adiponectin levels and decreased TNF-α levels. KICG1338 therapy also led to greater ß-cell preservation and less hepatic fat infiltration with decreased expressions of genes involved in inflammation and endoplasmic reticulum stress. These data demonstrate anti-diabetic efficacy of KICG1338, a novel GSK3ß inhibitor.

Synthesis and Electrochemical Properties of CNFs-Si Composites as an Anode Material for Li Secondary Batteries.

We have performed a study on the electrochemical and structural characteristics of CNFs-Si composites which are active anode material for lithium secondary batteries. Carbon nanofibers (CNFs) have been synthesized by Chemical Vapor Deposition (CVD) using Co and Cu catalysts. The CNFs on the surface of the Si particle can provide a flexible space to relieve the volumetric expansion during a charge. Therefore, the CNFs composites on Si particles were prepared on the basis of the following two processes: (1) CNFs were grown on the simple mechanical mixture of Si particles and catalysts (CNFs/Si); (2) CNFs were grown on the surface of a pyrolytic carbon that was coated with Si particles (CNFs/PC/Si). The morphology and composition of CNFs-Si composites were analyzed by SEM and EDS measurements. Crystallinity and amorphicity were investigated using XRD and Raman spectroscopy. The characteristics of the synthesized CNFs-Si composites were analyzed through XPS, TGA, and BET. The two different CNFs-Si composite materials were evaluated as the anodic material in three different electrode cells. We found that the initial capacity of the CNFs/PC/Si composite electrode was 1,361 mAh/g with retention rate of 28.4%, which was better than the retention rate of 4.9% with the CNFs/Si electrode.

Characteristics and Electrochemical Performance of Si-Carbon Nanofibers Composite as Anode Material for Binder-Free Lithium Secondary Batteries.

The carbon nanofibers (CNFs) and Si-CNFs composite were synthesized using a chemical vapor deposition (CVD) method with an iron-copper catalyst and silicon-covered Ni foam. Acetylene as a carbon source was flowed into the quartz reactor of a tubular furnace heated to 600 degrees C. This temperature was maintained for 10 min to synthesize the CNFs. The morphologies, compositions, and crystal quality of the prepared CNFs were characterized by Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), X-ray Diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The electrochemical characteristics of the Si-CNFs composite as an anode of the Li secondary batteries were investigated using a three-electrode cell. The as-deposited Si-CNF composite on the Ni foam was directly employed as an working electrode without any binder, and lithium foil was used as the counter and reference electrode. A glass fiber separator was used as the separator membrane. Two kinds of electrolytes were employed; 1) 1 M LiPF6 was dissolved in a mixture of EC (ethylene carbonate): PC (propylene carbonate): EMC (Ethyl methyl carbonate) in a 1:1:1 volume ratio and 2) 1 M LiClO4 was dissolved in a mixture of propylene carbonate (PC): ethylene carbonate (EC) in a 1:1 volume ratio. The galvanostatic charge-discharge cycling and cyclic voltammetry measurements were carried out at room temperature by using a battery tester. The resulting Si-CNFs composite achieved the large discharge capacity of 613 mAh/g and much improved cycle-ability with the retention rate of 87% after 20 cycles.

Novel strategy for successful long-term hematopoietic recovery after transplanting a limited number of hematopoietic stem/progenitor cells.

Various investigators have attempted to overcome the shortage of available hematopoietic stem/progenitor cells (HSPCs) by facilitating their engraftment after transplantation. Preconditioning of HSPCs with the granulocyte-derived cationic peptide LL-37 has been suggested as a useful strategy to facilitate engraftment of transplanted cells by enhancing their responsiveness to CXCL12. In this study, we evaluated whether LL-37 preconditioning is acceptable for clinical application. We found that the effect of LL-37 preconditioning was specific to clonogenic cells and was mediated specifically by increased calcium influx with the activation of downstream signaling through mammalian target of rapamycin complex 1 (mTORC1). Because hyperactivation of mTORC1 and the disruption of 5' adenosine monophosphate-activated protein kinase (AMPK) are known to deplete HSPC pools, we compared the repopulation capacity of HSPCs preconditioned with LL-37 and those preconditioned with AMPK activator (AICAR). In vivo competitive repopulation experiments revealed that LL-37 preconditioning impairs long-term repopulation of transplanted HSPCs, suggesting that this strategy might not acceptable for clinical applications in which long-term repopulation capacity is a prerequisite. AICAR preconditioning dramatically enhanced the long-term repopulation of transplanted HSPCs, however. Taken together, these results suggest that future strategies to ensure successful transplantation outcomes should focus on protecting HSPCs from various stimuli during their homing to the bone marrow niches rather than activating them before transplantation.

Growth of carbon nanofibers using resol-type phenolic resin and cobalt(II) catalyst.

This study investigated carbon nanofibers (CNFs) grown on reticulated vitreous carbon (RVC) foam through catalytic deposition of ethylene. Before growing the CNFs, Co(II) on the RVC foam was expected to act as a catalyst by deposition. The preparation of the CNFs was a two-step process. The first step was preparing the RVC from polyurethane (PU) foam. Changes in weight over time were evaluated using two kinds of resol. The change in the mass and state of the sample with the change in temperature was studied during the carbonization process. The second step was to prepare the CNFs. An OH group was attached by the oxidation of the RVC foam. A change in the shape and mass of the sample was observed due to a change in nitric acid concentration and oxidation time. Then, cobalt was deposited to grow CNFs on the RVC foam. Hydrolysis helped to deposit the Co(ll) on the RVC foam. The appropriate time and temperature were investigated for the reduction process. In the last step, CNFs were prepared by the introducing ethylene gas. The resulting samples were analyzed using scanning electron microscopy, energy dispersive spectroscopy, N2-sorption, and X-ray photoelectron spectroscopy.

4-Deoxypyridoxine improves the viability of isolated pancreatic islets ex vivo.

The successful islet transplantation, for the treatment of type 1 diabetes, depends on the quantity and the quality of transplanted islets. Previously, it has reported that the significant loss of isolated islet mass could be prevented by sphingolipid metabolite, sphinogosine 1-phophate (S1P). This study was performed to elucidate whether the beneficial effects of S1P maintaining isolated pancreatic islets ex vivo are mimicked by modulation of intracellular S1P. We tested the in vitro effect of various agents that modulate intracellular S1P levels in insulinoma cell lines and isolated islets to compare their anti-apoptotic effects with that of S1P. As results, we discovered that 4-deoxypyridoxine (DOP), which inhibits the degradation of intracellular S1P by inhibiting S1P lyase (SPL) activity, minimized the chemically induced apoptosis of insulinoma cell lines as S1P did. Also, supplementation of DOP in the culture media protected the regression of isolated islets that have been maintained ex vivo at least for 18 h providing the evidence of increasing viability of isolated islets with DOP, which impaired SPL activity. In conclusion, these results suggest that the application of SPL inhibitors could be considered as a supplement for the maintenance of viable islets isolated from donor sources in the process of islet transplantation.

Differential effects of trimetazidine on vascular smooth muscle cell and endothelial cell in response to carotid artery balloon injury in diabetic rats.

BACKGROUND: Treatment with trimetazidine (TMZ), 1-[2,3,4-trimethoxybenzyl] piperazine, dihydrochloride, improves cardiac function and ameliorates endothelial dysfunction. However, its potential efficacy against restenosis after balloon injury has not been addressed. We investigated the effect of TMZ on reducing the occurrence of restenosis in the carotid artery in response to balloon injury and explored potential mechanisms for the effects. MATERIAL AND METHODS: Streptozotocin (40 mg/kg)-injected Sprague-Dawley rats and Otsuka Long-Evans Tokushima Fatty rats were used for type 1 and type 2 diabetes models, respectively. Both types of rats were divided into three groups: control and TMZ treatment 10 and 20mg/kg per day (n=10 per group). TMZ or normal saline was given orally from 2 weeks before to 2 weeks after carotid injury. RESULTS: Four weeks of TMZ treatment resulted in a significant and dose-dependent reduction in the intima-media ratio in diabetic rats. This effect was accompanied by decreased proliferation of vascular smooth muscle cells (VSMCs) and accelerated re-endothelialization after carotid balloon injury. In vitro study with VSMCs decreased proliferation and migration, while human umbilical vein endothelial cells (HUVECs) increased proliferation and decreased apoptosis after TMZ treatment. Antioxidative effects of TMZ were observed in both VSMCs and HUVECs. CONCLUSIONS: Reduction of restenosis by TMZ treatment involved changes in antioxidative and anti-inflammatory properties, which are cell-specific effects on either survival or apoptosis. The specific actions and physiological effects of TMZ may contribute to better understanding of the pathogenesis of atherosclerosis, which is a major complication of diabetes mellitus.

Effect of a dipeptidyl peptidase-IV inhibitor, des-fluoro-sitagliptin, on neointimal formation after balloon injury in rats.

BACKGROUND: Recently, it has been suggested that enhancement of incretin effect improves cardiac function. We investigated the effect of a DPP-IV inhibitor, des-fluoro-sitagliptin, in reducing occurrence of restenosis in carotid artery in response to balloon injury and the related mechanisms. METHODS AND FINDINGS: Otsuka Long-Evans Tokushima Fatty rats were grouped into four: control (normal saline) and sitagliptin 100, 250 and 500 mg/kg per day (n = 10 per group). Sitagliptin or normal saline were given orally from 1 week before to 2 weeks after carotid injury. After 3 weeks of treatment, sitagliptin treatment caused a significant and dose-dependent reduction in intima-media ratio (IMR) in obese diabetic rats. This effect was accompanied by improved glucose homeostasis, decreased circulating levels of high-sensitivity C-reactive protein (hsCRP) and increased adiponectin level. Moreover, decreased IMR was correlated significantly with reduced hsCRP, tumor necrosis factor-α and monocyte chemoattractant protein-1 levels and plasminogen activator inhibitor-1 activity. In vitro evidence with vascular smooth muscle cells (VSMCs) demonstrated that proliferation and migration were decreased significantly after sitagliptin treatment. In addition, sitagliptin increased caspase-3 activity and decreased monocyte adhesion and NFκB activation in VSMCs. CONCLUSIONS: Sitagliptin has protective properties against restenosis after carotid injury and therapeutic implications for treating macrovascular complications of diabetes.

Endothelial progenitor cell cotransplantation enhances islet engraftment by rapid revascularization.

Impaired revascularization of transplanted islets is a critical problem that leads to progressive islet loss. Since endothelial progenitor cells (EPCs) are known to aid neovascularization, we aimed to enhance islet engraftment by cotransplanting EPCs with islets. Porcine islets, with (islet-EPC group) or without (islet-only group) human cord blood-derived EPCs, were transplanted into diabetic nude mice. The islet-EPC group reached euglycemia by ∼11 days posttransplantation, whereas the islet-only group did not. Also, the islet-EPC group had a higher serum porcine insulin level than the islet-only group. Islets from the islet-EPC group were more rapidly revascularized at the early period of transplantation without increment of final capillary density at the fully revascularized graft. Enhanced revascularization rate in the islet-EPC group was mainly attributed to stimulating vascular endothelial growth factor-A production from the graft. The rapid revascularization by EPC cotransplantation led to better graft perfusion and recovery from hypoxia. EPC cotransplantation was also associated with greater ß-cell proliferation, probably by more basement membrane production and hepatocyte growth factor secretion. In conclusion, cotransplantation of EPCs and islets induces better islet engraftment by enhancing the rate of graft revascularization. These findings might provide a directly applicable tool to enhance the efficacy of islet transplantation in clinical practice.