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1.
Front Endocrinol (Lausanne) ; 14: 1175640, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37409229

RESUMO

Aim: In a recent randomized, multicenter trial (NCT02814838) a short-term anti-inflammatory treatment with ladarixin (LDX; an inhibitor of the CXCR1/2 chemokine receptors) did not show benefit on preserving residual beta cell function in new-onset type 1 diabetes. We present a post hoc analysis of trial patients in the predefined subgroup analysis developed according to baseline daily insulin requirement (DIR) tertiles. Method: A double-blind, randomized (2:1), placebo-controlled study was conducted in 45 men and 31 women (aged 18-46 years) within 100 days of the first insulin administration. Patients received LDX (400 mg twice daily) for three cycles of 14 days on/14 days off, or placebo. The primary endpoint was the area under the curve for C-peptide [AUC (0-120 min)] in response to a 2-h mixed meal tolerance test (MMTT) at week 13 ± 1. Seventy-five patients completed the week 13 MMTT and were divided into three groups according to the DIR tertiles: lower, ≤ 0.23U/kg/die (n = 25); middle, 0.24-0.40 U/kg/die (n = 24); upper, ≥ 0.41 U/kg/die (n = 26). Results: When considering the patients in the upper tertile (HIGH-DIR), C-peptide AUC (0-120 min) at 13 weeks was higher in the LDX group (n = 16) than in the placebo (n = 10) group [difference: 0.72 nmol/L (95% CI 0.9-1.34), p = 0.027]. This difference reduced over time (0.71 nmol/L at 26 weeks, p = 0.04; 0.42 nmol/L at 52 weeks, p = 0.29), while it has never been significant at any time in patients in the lower and/or middle tertile (LOW-DIR). We characterized at baseline the HIGH-DIR and found that endo-metabolic (HOMA-B, adiponectin, and glucagon-to-C-peptide ratio) and immunologic (chemokine (C-C motif) ligand 2 (CCL2)/monocyte chemoattractant protein 1 (MCP1) and Vascular Endothelial Growth Factor (VEGF)) features distinguished this group from LOW-DIR. Conclusion: While LDX did not prevent the progressive loss of beta-cell function in the majority of treated subjects, the post hoc analysis suggests that it could work in subjects with HIGH-DIR at baseline. As we found differences in endo-metabolic and immunologic parameters within this subgroup, this generates the hypothesis that the interactions between host factors and drug action can contribute to its efficacy. Further research is needed to evaluate this hypothesis.


Assuntos
Diabetes Mellitus Tipo 1 , Masculino , Humanos , Feminino , Diabetes Mellitus Tipo 1/tratamento farmacológico , Peptídeo C/metabolismo , Estudos Prospectivos , Fator A de Crescimento do Endotélio Vascular , Insulina/uso terapêutico
3.
Exp Clin Endocrinol Diabetes ; 130(10): 638-651, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35451037

RESUMO

Non-mesenchymal pancreatic cells are a potential source for cell replacement. Their transdifferentiation can be achieved by triggering epigenetic remodeling through e. g. post-translational modification of histones. Valproic acid, a branched-chain saturated fatty acid with histone deacetylase inhibitor activity, was linked to the expression of key transcription factors of pancreatic lineage in epithelial cells and insulin transcription. However, the potential of valproic acid to cause cellular reprogramming is not fully understood. To shed further light on it we employed next-generation RNA sequencing, real-time PCR, and protein analyses by ELISA and western blot, to assess the impact of valproic acid on transcriptome and function of Panc-1-cells. Our results indicate that valproic acid has a significant impact on the cell cycle, cell adhesion, histone H3 acetylation, and metabolic pathways as well as the initiation of epithelial-mesenchymal transition through acetylation of histone H3 resulting in α-cell-like characteristics. We conclude that human epithelial pancreatic cells can be transdifferentiated into cells with endocrine properties through epigenetic regulation by valproic acid favoring an α-cell-like phenotype.


Assuntos
Adenocarcinoma , Insulinas , Humanos , Ácido Valproico/farmacologia , Histonas/metabolismo , Transdiferenciação Celular , Inibidores de Histona Desacetilases/farmacologia , Epigênese Genética , Fatores de Transcrição/metabolismo , Insulinas/metabolismo
4.
Biol Methods Protoc ; 7(1): bpab023, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35036572

RESUMO

Free fatty acids are essentially involved in the pathogenesis of chronic diseases such as diabetes mellitus, non-alcoholic fatty liver disease, and cardiovascular disease. They promote mitochondrial dysfunction, oxidative stress, respiratory chain uncoupling, and endoplasmic reticulum stress and modulate stress-sensitive pathways. These detrimental biological effects summarized as lipotoxicity mainly depend on fatty acid carbon chain length, degree of unsaturation, concentration, and treatment time. Preparation of fatty acid solutions involves dissolving and complexing. Solvent toxicity and concentration, amount of bovine serum albumin (BSA), and ratio of albumin to fatty acids can vary significantly between equal concentrations, mediating considerable harmful effects and/or interference with certain assays such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Herein, we studied the impact of commonly used solvents ethanol and dimethyl sulfoxide and varying concentrations of BSA directly and in solution with oleic acid on MTT to formazan conversion, adenosine triphosphate level, and insulin content and secretion of murine ß-cell line MIN6 employing different treatment duration. Our data show that experimental outcomes and assay readouts can be significantly affected by mere preparation of fatty acid solutions and should thus be carefully considered and described in detail to ensure comparability and distinct evaluation of data.

5.
Nutr Neurosci ; 25(9): 1823-1835, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33814001

RESUMO

Objectives: Human nutrition plays an important role in prevention or at least slowing down the progression of age- and diet-related diseases. Thereby, mitochondrial dysfunction represents one common underlying mechanism, which is being investigated in mouse models. However, the influence of the selected diets in preclinical studies on cognition and mitochondrial function has not yet been reported cohesively.Methods: Therefore, we present the results of three different studies that addressed this question. First, we investigated the influence of two standard control chow diets and a special diet low in antioxidants over 6 months in aged NMRI mice. Additionally, a 70% high-fat (HF) chow diet as well as a western-style diet (WSD) rich in lard and fructose were examined in C57/BL6 mice. Cognitive performance, mitochondrial function and bioenergetics in the brain were investigated. Moreover, cerebral expression of genes involved in biogenesis and antioxidant defence (citrate synthase, complex I, complex IV, SOD2, Cat1, GPx-1) were quantified.Results: The results show that a modified, low antioxidant diet increased ATP levels in the brain of aged mice, while cognitive functions remained largely unaffected. A HF diet also showed significant effects on ATP levels and gene expression levels of relevant antioxidant markers, while the WSD had marginal effects on mitochondrial function and bioenergetics in the brain.Discussion: Our results indicate that standard- and special diets have an impact on cognition and mitochondrial function in the brain. Thus, appropriate caution is warranted when selecting a suitable diet for preclinical studies in mice.


Assuntos
Antioxidantes , Mitocôndrias , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/farmacologia , Animais , Antioxidantes/farmacologia , Encéfalo/metabolismo , Citrato (si)-Sintase/metabolismo , Citrato (si)-Sintase/farmacologia , Cognição , Dieta Hiperlipídica , Frutose , Camundongos , Mitocôndrias/metabolismo
6.
Med Oncol ; 38(9): 109, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34357487

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is among the most deadly cancers. Since most patients develop resistance to conventional treatments, new approaches are in urgency. Valproic acid (VPA) was shown to induce apoptosis and reduce proliferation in PANC-1 cells. Wnt signaling pathway is known to be involved in apoptosis and PDAC onset. However, VPA-induced apoptosis and its impact on Wnt signaling in PDACs are not linked, yet. We aimed to calculate IC50 of VPA-induced PANC-1 cells by combined analyses of proliferation and apoptosis, while assessing its effect on Wnt signaling pathway. PANC-1 was induced with increased VPA doses and time points. Three independent proliferation and apoptosis assays were performed utilizing carboxyfluorescein succinimidyl ester and Annexin V/PI staining, respectively. Flow cytometry measurements were analyzed by CellQuest and NovoExpress. Taqman hydrolysis probes and SYBR Green PCR Mastermix were assessed in expression analyses of Wnt components utilizing 2-ΔΔCt method. Cell proliferation was inhibited by 50% at 2.5 mM VPA that evoked a significant apoptotic response. Among the screened Wnt components and target genes, only LEF1 exhibited significant four-fold upregulation at this concentration. In conclusion, cancer studies mostly utilize MTT or BrdU assays in estimating cell proliferation and calculating IC50 of drugs, which provided conflicting VPA dosages utilizing PANC-1 cells. Our novel combined approach enabled specific, accurate and reproducible IC50 calculation at single cell basis with no apparent effect on Wnt signaling components. Future studies are needed to clarify the role of LEF1 in this model.


Assuntos
Apoptose , Carcinoma Ductal Pancreático/patologia , Proliferação de Células , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Neoplasias Pancreáticas/patologia , Ácido Valproico/farmacologia , Via de Sinalização Wnt/efeitos dos fármacos , Anticonvulsivantes/farmacologia , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Humanos , Concentração Inibidora 50 , Fator 1 de Ligação ao Facilitador Linfoide/genética , Fator 1 de Ligação ao Facilitador Linfoide/metabolismo , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Células Tumorais Cultivadas
7.
Antioxidants (Basel) ; 10(2)2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33672062

RESUMO

Lipotoxicity is a major contributor to type 2 diabetes mainly promoting mitochondrial dysfunction. Lipotoxic stress is mediated by elevated levels of free fatty acids through various mechanisms and pathways. Impaired peroxisome proliferator-activated receptor (PPAR) signaling, enhanced oxidative stress levels, and uncoupling of the respiratory chain result in ATP deficiency, while ß-cell viability can be severely impaired by lipotoxic modulation of PI3K/Akt and mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase (ERK) pathways. However, fatty acids are physiologically required for an unimpaired ß-cell function. Thus, preparation, concentration, and treatment duration determine whether the outcome is beneficial or detrimental when fatty acids are employed in experimental setups. Further, ageing is a crucial contributor to ß-cell decay. Cellular senescence is connected to loss of function in ß-cells and can further be promoted by lipotoxicity. The potential benefit of nutrients has been broadly investigated, and particularly polyphenols were shown to be protective against both lipotoxicity and cellular senescence, maintaining the physiology of ß-cells. Positive effects on blood glucose regulation, mitigation of oxidative stress by radical scavenging properties or regulation of antioxidative enzymes, and modulation of apoptotic factors were reported. This review summarizes the significance of lipotoxicity and cellular senescence for mitochondrial dysfunction in the pancreatic ß-cell and outlines potential beneficial effects of plant-based nutrients by the example of polyphenols.

8.
Stem Cell Res Ther ; 12(1): 121, 2021 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-33579357

RESUMO

BACKGROUND: Type 1 diabetes mellitus (T1D) is characterized by the autoimmune destruction of the pancreatic ß cells. The transplantation of mesenchymal stromal/stem cells (MSC) was reported to rescue the damaged pancreatic niche. However, there is an ongoing discussion on whether direct physical contact between MSC and pancreatic islets results in a superior outcome as opposed to indirect effects of soluble factors released from the MSC entrapped in the lung microvasculature after systemic administration. Hence, MSC were studied in direct contact (DC) and indirect contact (IDC) with murine pancreatic ß cell line MIN6-cells damaged by nitrosourea derivative streptozotocin (STZ) in vitro. Further, the protective and antidiabetic outcome of MSC transplantation was evaluated through the intrapancreatic route (IPR) and intravenous route (IVR) in STZ-induced diabetic NMRI nude mice. METHODS: MSC were investigated in culture with STZ-damaged MIN6-cells, either under direct contact (DC) or separated through a semi-permeable membrane (IDC). Moreover, multiple low doses of STZ were administered to NMRI nude mice for the induction of hyperglycemia. 0.5 × 106 adipose-derived mesenchymal stem cells (ADMSC) were transferred through direct injection into the pancreas (IPR) or the tail vein (IVR), respectively. Bromodeoxyuridine (BrdU) was injected for the detection of proliferating islet cells in vivo, and real-time polymerase chain reaction (RT-PCR) was employed for the measurement of the expression of growth factor and immunomodulatory genes in the murine pancreas and human MSC. Phosphorylation of AKT and ERK was analyzed with Western blotting. RESULTS: The administration of MSC through IPR ameliorated hyperglycemia in contrast to IVR, STZ, and non-diabetic control in a 30-day window. IPR resulted in a higher number of replicating islet cells, number of islets, islet area, growth factor (EGF), and balancing of the Th1/Th2 response in vivo. Physical contact also provided a superior protection to MIN6-cells from STZ through the AKT and ERK pathway in vitro in comparison with IDC. CONCLUSION: Our study suggests that the physical contact between MSC and pancreatic islet cells is required to fully unfold their protective potential.


Assuntos
Diabetes Mellitus Experimental , Ilhotas Pancreáticas , Transplante de Células-Tronco Mesenquimais , Animais , Diabetes Mellitus Experimental/terapia , Insulina , Camundongos , Camundongos Nus , Estreptozocina
9.
Exp Clin Endocrinol Diabetes ; 129(5): 357-364, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-32052390

RESUMO

Mesenchymal stem cells are useful tools employed in clinical and preclinical medicine. Their beneficial potential in especially degenerative as well as autoimmune diseases is a constant focus of research. Regarding diabetes mellitus, transplantation of stem cells is seen as a possible therapeutic approach to overcome the loss of endocrine pancreatic cells. It was reported that co-transplantation of mesenchymal stem cells with pancreatic islet cells improves function and survival of the graft. However, these multipotent progenitors may be able to form tumors, especially under immunosuppressed conditions. Histone deacetylase inhibitors might offer the potential to overcome this issue. These small molecules can induce cell differentiation and control proliferation. Their potential to control lineage development of stem cells has been distinctly demonstrated in the treatment of cancer, mainly in hematopoietic neoplasias.In this study, we demonstrate that human bone marrow-derived mesenchymal stem cells exhibit low carcinogenic potential in an immunosuppressed condition in vivo. Further, the effect of histone deacetylase inhibitors LBH589, MS-275, and MGCD0103 was examined after normalizing histone deacetylase activities in culture. Interestingly, transcripts of insulin gene enhancer protein and paired-box-gene 6, two markers of pancreatic endocrine differentiation were constitutively expressed in the cell line. The broad spectrum inhibitor of class I and class II histone deacetylases LBH589 upregulated the expression of these transcription factors in a significant way, whereas addition of selective class I histone deacetylase inhibitors MS-275 and MGCD0103 did not result in significant changes in gene expression.In conclusion, we deliver evidence that a combined class I and II histone deacetylase inhibition is able to modulate the transcripts of differentiation markers of mesenchymal stem cells. The treatment holds the capability to facilitate endocrine differentiation in future approaches to replace endocrine cells by stem cell therapy.


Assuntos
Células da Medula Óssea/efeitos dos fármacos , Carcinogênese/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Inibidores de Histona Desacetilases/farmacologia , Ilhotas Pancreáticas/efeitos dos fármacos , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/efeitos dos fármacos , Panobinostat/farmacologia , Humanos
10.
Stem Cell Res Ther ; 11(1): 497, 2020 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-33239104

RESUMO

BACKGROUND: Mesenchymal stem cells (MSC) are non-haematopoietic, fibroblast-like multipotent stromal cells. In the injured pancreas, these cells are assumed to secrete growth factors and immunomodulatory molecules, which facilitate the regeneration of pre-existing ß-cells. However, when MSC are delivered intravenously, their majority is entrapped in the lungs and does not reach the pancreas. Therefore, the aim of this investigation was to compare the regenerative support of hTERT-MSC (human telomerase reverse transcriptase mesenchymal stem cells) via intrapancreatic (IPR) and intravenous route (IVR). METHODS: hTERT-MSC were administered by IPR and IVR to 50% pancreatectomized NMRI nude mice. After eight days, blood glucose level, body weight, and residual pancreatic weight were measured. Proliferating pancreatic ß-cells were labelled and identified with bromodeoxyuridine (BrdU) in vivo. The number of residual islets and the frequency of proliferating ß-cells were compared in different groups with sequential pancreatic sections. The pancreatic insulin content was evaluated by enzyme-linked immunosorbent assay (ELISA) and the presence of hTERT-MSC with human Alu sequence. Murine gene expression of growth factors, ß-cell specific molecules and proinflammatory cytokines were inspected by real-time polymerase chain reaction (RT-PCR) and Western blot. RESULTS: This study evaluated the regenerative potential of the murine pancreas post-hTERT-MSC administration through the intrapancreatic (IPR) and intravenous route (IVR). Both routes of hTERT-MSC transplantation (IVR and IPR) increased the incorporation of BrdU by pancreatic ß-cells compared to control. MSC induced epidermal growth factor (EGF) expression and inhibited proinflammatory cytokines (IFN-γ and TNF-α). FOXA2 and PDX-1 characteristics for pancreatic progenitor cells were activated via AKT/ PDX-1/ FoxO1 signalling pathway. CONCLUSION: The infusion of hTERT-MSC after partial pancreatectomy (Px) through the IVR and IPR facilitated the proliferation of autochthonous pancreatic ß-cells and provided evidence for a regenerative influence of MSC on the endocrine pancreas. Moderate benefit of IPR over IVR was observed which could be a new treatment option for preventing diabetes mellitus after pancreas surgery.


Assuntos
Diabetes Mellitus Experimental , Regulação para Baixo , Células Secretoras de Insulina , Células-Tronco Mesenquimais , Animais , Proteína Forkhead Box O1/genética , Camundongos , Camundongos Nus
11.
Stem Cell Res Ther ; 10(1): 240, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-31387633

RESUMO

BACKGROUND: Adipose-derived mesenchymal stem cells (ADMSC) are non-haematopoietic, fibroblast-like multipotent progenitor cells. They have the potential for trilineage (adipocyte, chondrocyte and osteocyte) differentiation as well as differentiation into endocrine pancreatic progenitors. In diabetic or cancer therapy, somatostatin (SST) expression plays a vital role. Small molecules such as valproic acid (VPA) and micronutrients like vitamin D3 have differentiation potential in ADMSC. Therefore, the aim of this study was to investigate the role of vitamin D3 machinery and its metabolic enzymes in ADMSC. Furthermore, the reprogramming effect of vitamin D3 and VPA was evaluated on somatostatin expression in pancreatic lineage differentiation. METHODS: ADMSC were characterised based on their cell surface marker profile using flow cytometry. Specific adipogenic and osteogenic differentiation protocols were used in this study. Gene expression of several pluripotent, endodermal, pancreatic progenitor and pancreatic endocrine lineage markers were investigated in native ADMSC and after stimulation with different concentration of vitamin D3 for five consecutive days (0, 50, 100, 150 nM) and VPA (0.5, 1, 1.5, 2 mM) by real-time PCR. Furthermore, somatostatin expression was confirmed with ELISA and immunocytochemistry. RESULTS: In ADMSC, the expression of somatostatin mRNA, the vitamin D receptor (VDR) and its metabolising enzymes 1 α-Hydroxylase, 24-Hydroxylase and 25-Hydroxylase were detected. Upon stimulation with vitamin D3, nuclear translocation of vitamin D receptor (VDR) was observed. Interestingly, the presence of vitamin D3 reduced the transcription of the somatostatin gene. By contrast, VPA treatment of cultivated ADMSC showed enhancing effect on somatostatin gene expression. No other pluripotent, endodermal, pancreatic progenitor or pancreatic endocrine lineage mRNA expression was modulated under the influence of vitamin D3 and VPA. CONCLUSION: Human ADMSC carry the VDR. The vitamin D metabolising enzyme 25-Hydroxylase responded to the addition of vitamin D3. Moreover, our results demonstrate that somatostatin expression in ADMSC is constitutive, partially secreted and regulated by vitamin D3 and VPA.


Assuntos
Colecalciferol/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Somatostatina/metabolismo , Ácido Valproico/farmacologia , 25-Hidroxivitamina D3 1-alfa-Hidroxilase/metabolismo , Adipogenia , Tecido Adiposo/citologia , Diferenciação Celular , Células Cultivadas , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Osteogênese , RNA Mensageiro/metabolismo , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Somatostatina/genética , Vitamina D3 24-Hidroxilase/metabolismo
12.
J Vis Exp ; (135)2018 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-29782007

RESUMO

Pancreatic islet transplantation to reduce hyperglycemia is highly successful in rodents with chemically-induced diabetes. The most common transplantation site in experimental islet transplantation is the kidney capsule. However, as less is known about the interaction of pancreatic islets with blood constituents, it also makes sense to utilize the portal vein approach in experimental islet transplantation. This protocol demonstrates an intraportal islet transplantation technique in NMRI nude mice. Streptozotocin (180 mg/kg) is injected intraperitoneally to induce hyperglycemia in recipient mice. They are considered as diabetic at a non-fasting blood glucose level greater than 20 mmol/L. One day prior to transplantation, mouse pancreatic islets are isolated from the donor pancreas by collagenase digestion; a minimum of 350 islets are utilized per diabetic recipient. Depending upon the islet isolation yield, two or more donor mice are utilized per recipient. After overnight culture at 37 °C, islets are administered into the recipient liver via the portal vein. After surgery, the mice are protected in red Makrolon houses and observed until are awake. This protocol maintains glycemic control for 120 days in syngeneic mice and 15 days in allogeneic mice.


Assuntos
Diabetes Mellitus Experimental/terapia , Transplante das Ilhotas Pancreáticas/métodos , Ilhotas Pancreáticas/patologia , Animais , Diabetes Mellitus Experimental/sangue , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus
13.
Stem Cells Int ; 2016: 3764681, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27047547

RESUMO

Type 1 diabetes is an autoimmune disease resulting in the permanent destruction of pancreatic islets. Islet transplantation to portal vein provides an approach to compensate for loss of insulin producing cells. Clinical trials demonstrated that even partial islet graft function reduces severe hypoglycemic events in patients. However, therapeutic impact is restrained due to shortage of pancreas organ donors and instant inflammation occurring in the hepatic environment of the graft. We summarize on what is known about regenerative therapy in type 1 diabetes focusing on pancreatic islet transplantation and new avenues of cell substitution. Metabolic pathways and energy production of transplanted cells are required to be balanced and protection from inflammation in their intravascular bed is desired. Mesenchymal stem cells (MSCs) have anti-inflammatory features, and so they are interesting as a therapy for type 1 diabetes. Recently, they were reported to reduce hyperglycemia in diabetic rodents, and they were even discussed as being turned into endodermal or pancreatic progenitor cells. MSCs are recognized to meet the demand of an individual therapy not raising the concerns of embryonic or induced pluripotent stem cells for therapy.

14.
Am J Clin Nutr ; 100(4): 1059-68, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25030779

RESUMO

BACKGROUND: Isomaltulose attenuates postprandial glucose and insulin concentrations compared with sucrose in patients with type 2 diabetes mellitus (T2DM). However, the mechanism by which isomaltulose limits postprandial hyperglycemia has not been clarified. OBJECTIVE: The objective was therefore to assess the effects of bolus administration of isomaltulose on glucose metabolism compared with sucrose in T2DM. DESIGN: In a randomized, double-blind, crossover design, 11 participants with T2DM initially underwent a 3-h euglycemic-hyperinsulinemic (0.8 mU · kg(-1) · min(-1)) clamp that was subsequently combined with 1 g/kg body wt of an oral (13)C-enriched isomaltulose or sucrose load. Hormonal responses and glucose kinetics were analyzed during a 4-h postprandial period. RESULTS: Compared with sucrose, absorption of isomaltulose was prolonged by ∼50 min (P = 0.004). Mean plasma concentrations of insulin, C-peptide, glucagon, and glucose-dependent insulinotropic peptide were ∼10-23% lower (P < 0.05). In contrast, glucagon-like peptide 1 (GLP-1) was ∼64% higher (P < 0.001) after isomaltulose ingestion, which results in an increased insulin-to-glucagon ratio (P < 0.001) compared with sucrose. The cumulative amount of systemic glucose appearance was ∼35% lower after isomaltulose than after sucrose (P = 0.003) because of the reduction in orally derived and endogenously produced glucose and a higher first-pass splanchnic glucose uptake (SGU). Insulin action was enhanced after isomaltulose compared with sucrose (P = 0.013). CONCLUSIONS: Ingestion of slowly absorbed isomaltulose attenuates postprandial hyperglycemia by reducing oral glucose appearance, inhibiting endogenous glucose production (EGP), and increasing SGU compared with ingestion of rapidly absorbed sucrose in patients with T2DM. In addition, GLP-1 secretion contributes to a beneficial shift in the insulin-to-glucagon ratio, suppression of EGP, and enhancement of SGU after isomaltulose consumption. This trial was registered at clinicaltrials.gov as NCT01070238.


Assuntos
Metabolismo dos Carboidratos , Diabetes Mellitus Tipo 2/sangue , Carboidratos da Dieta/farmacocinética , Isomaltose/análogos & derivados , Período Pós-Prandial , Glicemia/metabolismo , Peptídeo C/sangue , Estudos Cross-Over , Método Duplo-Cego , Feminino , Polipeptídeo Inibidor Gástrico/sangue , Glucagon/sangue , Peptídeo 1 Semelhante ao Glucagon/sangue , Humanos , Hiperglicemia/sangue , Insulina/sangue , Isomaltose/farmacocinética , Masculino , Pessoa de Meia-Idade , Sacarose/farmacocinética
15.
PLoS One ; 8(12): e82639, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24349326

RESUMO

Substitution of pancreatic islets is a potential therapy to treat diabetes and it depends on reconstitution of islet's capillary network. In this study, we addressed the question whether stabilization of Glucagon-Like-Peptide-1 (GLP-1) by inhibiting Dipeptidyl Peptidase-IV (DPP-IV) increases ß-cell mass by modulating vascularization. Mouse or porcine donor islets were implanted under kidney capsule of diabetic mice treated with DPP-IV inhibitor sitagliptin. Grafts were analyzed for insulin production, ß-cell proliferation and vascularization. In addition, the effect of sitagliptin on sprouting and Vascular Endothelial Growth Factor (VEGF)-A expression was examined ex vivo. The cAMP response element-binding (CREB) and VEGF-A/ Vascular Endothelial Growth Factor Receptor (VEGFR)-2 signaling pathway leading to islet vascularization was explored. Sitagliptin increased mean insulin content of islet grafts and area of insulin-positive tissue as well as ß-cell proliferation. Interestingly, sitagliptin treatment also markedly increased endothelial cell proliferation, microvessel density and blood flow. Finally, GLP-1 (7-36) stimulated sprouting and VEGF expression, which was significantly enhanced by sitagliptin- mediated inhibition of DPP-IV. Our in vivo data demonstrate that sitagliptin treatment phosphorylated CREB and induced islet vascularization through VEGF-A/VEGFR-2 signaling pathway. This study paves a new pathway for improvement of islet transplantation in treating diabetes mellitus.


Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Dipeptidil Peptidase 4/metabolismo , Ilhotas Pancreáticas/irrigação sanguínea , Ilhotas Pancreáticas/metabolismo , Neovascularização Fisiológica , Transdução de Sinais , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Animais , Glicemia , Proliferação de Células/efeitos dos fármacos , Inibidores da Dipeptidil Peptidase IV/farmacologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Peptídeo 1 Semelhante ao Glucagon/sangue , Insulina/biossíntese , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Transplante das Ilhotas Pancreáticas , Camundongos , Neovascularização Fisiológica/efeitos dos fármacos , Pirazinas/farmacologia , Fluxo Sanguíneo Regional/efeitos dos fármacos , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fosfato de Sitagliptina , Suínos , Serina-Treonina Quinases TOR/metabolismo , Triazóis/farmacologia
16.
World J Urol ; 31(4): 711-6, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23519458

RESUMO

OBJECTIVES: The prostatitis syndrome is classified into bacterial prostatitis (acute and chronic), chronic pelvic pain syndrome and asymptomatic prostatitis. The aim of this report is to review current management standards for bacterial prostatitis. METHODS: A research was performed on literature dealing with acute and chronic bacterial prostatitis. RESULTS: There is a consensus on diagnostic management of bacterial prostatitis comprising microbiological sampling of midstream urine in acute bacterial prostatitis and performance of a bacterial localisation test in chronic bacterial prostatitis. Approximately 10 % of acute bacterial prostatitis cases eventually develop into chronic bacterial prostatitis and further 10 % into chronic pelvic pain syndrome. Bacterial isolates causing acute bacterial prostatitis are highly virulent strains comprising an array of different virulence factors. Presumably, the additional ability of isolates to form biofilms might be one factor amongst others to facilitate development of chronic bacterial prostatitis. Therapy for infectious prostatitis is standardised with antibiotics as the primary agents, empirically administered in acute prostatitis and after susceptibility testing in chronic bacterial prostatitis. Fluoroquinolones exhibit more favourable pharmacological properties; therefore, fluoroquinolones have been recommended as first-line agents in the treatment for chronic bacterial prostatitis. Antibiotic resistance to fluoroquinolones, however, is increasing and is posing significant clinical problems. Further studies on alternative antibiotics active within the prostate are therefore needed both for prophylaxis in transrectal prostate biopsy, for example, and for therapy of chronic bacterial prostatitis. CONCLUSIONS: Bacterial prostatitis has developed into well-managed entities with increasing antimicrobial resistance being the most severe drawback of yielding therapeutic success.


Assuntos
Infecções Bacterianas/tratamento farmacológico , Prostatite/classificação , Prostatite/tratamento farmacológico , Doença Aguda , Antibacterianos/uso terapêutico , Infecções Bacterianas/complicações , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/microbiologia , Doença Crônica , Progressão da Doença , Farmacorresistência Bacteriana , Fluoroquinolonas/uso terapêutico , Humanos , Masculino , Prostatite/diagnóstico , Prostatite/microbiologia
17.
Biol Trace Elem Res ; 151(3): 384-99, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23271678

RESUMO

The anti-carcinogenic effects of sulforaphane (SFN) are based on the up-regulation of antioxidant enzymes (AE) and phase II enzymes (PIIE) through the transcription factor Nrf2. Current knowledge on the roles of the SFN precursor glucoraphanin (GRA) on these processes is limited. Anti-carcinogenic effects of Se depending on glutathione peroxidase (GPx) activity have also been reported. We studied effects and possible synergisms of Se and GRA on the expression and activity of a broad spectrum of AE and PIIE in jejunum, colon and the liver of rats fed diets differing in Se and GRA concentration. In all organs, GPx1 mRNA expression was 70 % to 90 % lower in Se deficiency than in Se sufficiency. GPx2 expression increased in jejunum and liver under Se deficiency and decreased in the colon. Se deficiency increased most colonic AE and PIIE compared to Se adequacy. Adequate and in particular supranutritive Se combined with GRA increased colonic AE and PIIE expression up to 3.72-fold. In the liver Se deficiency raised the expression of AE and PIIE up to 4.49-fold. GRA attenuated liver AE and PIIE response in Se deficiency. Expression- and correlation analyses revealed that Keap1 mRNA better reflects AE and PIIE gene expression than Nrf2 mRNA. We conclude that: (1) GPx1 sensitively indicates Se deficiency; (2) the influence of Se and Nrf2/Keap1 on GPx2 expression depends on the organ; (3) GRA combined with supranutritive Se may effectively protect against inflammation and colon cancer; (4) future investigations on AE and PIIE expression should consider the role of Keap1 to a higher extent.


Assuntos
Antioxidantes/metabolismo , Glucosinolatos/farmacologia , Imidoésteres/farmacologia , Intestino Delgado/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/enzimologia , Selênio/administração & dosagem , Selênio/farmacologia , Animais , Comportamento Alimentar , Glucosinolatos/administração & dosagem , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Imidoésteres/administração & dosagem , Intestino Delgado/enzimologia , Intestino Delgado/metabolismo , Fígado/metabolismo , Masculino , Oximas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Selênio/deficiência , Sulfóxidos
18.
Diabetes ; 61(8): 2045-53, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22586582

RESUMO

Islet transplantation provides an approach to compensate for loss of insulin-producing cells in patients with type 1 diabetes. However, the intraportal route of transplantation is associated with instant inflammatory reactions to the graft and subsequent islet destruction as well. Although matrix metalloprotease (MMP)-2 and -9 are involved in both remodeling of extracellular matrix and leukocyte migration, their influence on the outcome of islet transplantation has not been characterized. We observed comparable MMP-2 mRNA expressions in control and transplanted groups of mice, whereas MMP-9 mRNA and protein expression levels increased after islet transplantation. Immunostaining for CD11b (Mac-1)-expressing leukocytes (macrophage, neutrophils) and Ly6G (neutrophils) revealed substantially reduced inflammatory cell migration into islet-transplanted liver in MMP-9 knockout recipients. Moreover, gelatinase inhibition resulted in a significant increase in the insulin content of transplanted pancreatic islets and reduced macrophage and neutrophil influx compared with the control group. These results indicate that the increase of MMP-9 expression and activity after islet transplantation is directly related to enhanced leukocyte migration and that early islet graft survival can be improved by inhibiting MMP-9 (gelatinase B) activity.


Assuntos
Sobrevivência de Enxerto/fisiologia , Transplante das Ilhotas Pancreáticas/métodos , Ilhotas Pancreáticas/metabolismo , Inibidores de Metaloproteinases de Matriz , Animais , Antígeno CD11b/metabolismo , Captopril/farmacologia , Movimento Celular/efeitos dos fármacos , Inflamação/prevenção & controle , Insulina/metabolismo , Fígado/cirurgia , Macrófagos/fisiologia , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Suínos
19.
Food Funct ; 2(11): 654-64, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21959850

RESUMO

Data from human and animal trials have revealed contradictory results regarding the influence of selenium (Se) status on homocysteine (HCys) metabolism. It was hypothesised that sufficient Se reduces the flux of HCys through the transsulphuration pathway by decreasing the expression of glutathione (GSH) synthesising enzymes. Glucoraphanin (GRA) is a potent inducer of genes regulated via an antioxidant response element (ARE), including those of GSH biosynthesis. We tested the hypothesis that GRA supplementation to rat diets lowers plasma HCys levels by increasing GSH synthesis. Therefore 96 weaned albino rats were assigned to 8 groups of 12 and fed diets containing four different Se levels (15, 50, 150 and 450 µg kg(diet)(-1)), either without GRA (groups: C15, C50, C150 and C450) or in combination with 700 µmol GRA kg(diet)(-1) (groups G15, G50, G150 and G450). Rats fed the low Se diets C15 and G15 showed an impressive decrease of plasma HCys. Se supplementation increased plasma HCys and lowered GSH significantly by reducing the expression of GSH biosynthesis enzymes. As new molecular targets explaining these results, we found a significant down-regulation of the hepatic GSH exporter MRP4 and an up-regulation of the HCys exporter Slco1a4. In contrast to our hypothesis, GRA feeding did not reduce plasma HCys levels in Se supplemented rats (G50, G150 and 450) through inducing GSH biosynthesis enzymes and MRP4, but reduced their mRNA in some cases to a higher extent than Se alone. We conclude: 1. That the long-term supplementation of moderate GRA doses reduces ARE-driven gene expression in the liver by increasing the intestinal barrier against oxidative stress. 2. That the up-regulation of ARE-regulated genes in the liver largely depends on GRA cleavage to free sulforaphane and glucose by plant-derived myrosinase or bacterial ß-glucosidases. As a consequence, higher dietary GRA concentrations should be used in future experiments to test if GRA or sulforaphane can be established as HCys lowering compounds.


Assuntos
Enzimas/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Glucosinolatos/administração & dosagem , Glutationa/biossíntese , Homocisteína/sangue , Imidoésteres/administração & dosagem , Fígado/enzimologia , Selênio/administração & dosagem , Regulação para Cima/efeitos dos fármacos , Animais , Antioxidantes/metabolismo , Vias Biossintéticas , Suplementos Nutricionais/análise , Enzimas/metabolismo , Humanos , Fígado/efeitos dos fármacos , Masculino , Oximas , Ratos , Elementos de Resposta , Sulfóxidos
20.
PLoS One ; 4(7): e6312, 2009 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-19617916

RESUMO

Thalidomide possesses both anti-inflammatory and anti-angiogenic properties. This study investigates its potential application in islet transplantation with a xenogenic transplantation model. Transplantation was performed using C57Bl/6 mice and NMRI nu/nu mice as recipients of porcine islets. Moreover, islet graft vasculature and inflammation were investigated to identify the mechanisms of thalidomide action. In the immunocompetent environment of C57Bl/6 mice, a fast graft rejection was observed. The group treated with thalidomide 200 mg/kg BW per day achieved and maintained euglycemia in the complete observation period for 42 days. The treated mice had more functional islet graft mass with less leukocyte infiltration. The pro-inflammatory TNF-alpha and VEGF content in islet grafted kidneys was significantly lowered by the treatment. By comparison, thalidomide was not effective in improving graft survival in immunocompromised nude mice. It strongly inhibited the VEGF and TNF-alpha-induced endothelial proliferation of isolated pig islets in a dose dependent manner. The magnitude of thalidomide's inhibitory effect was nearly identical to the effect of VEGF- receptor 2 inhibitor SU416 and anti-TNF-receptor 1 neutralizing antibody, and was reversed by sphingosine-1-phosphate. In conclusion, the anti-inflammatory effect of thalidomide improved islet graft survival and function in a transplantation model with a maximum immune barrier.


Assuntos
Anti-Inflamatórios/farmacologia , Ilhotas Pancreáticas/efeitos dos fármacos , Talidomida/farmacologia , Animais , Glicemia/análise , Ilhotas Pancreáticas/patologia , Camundongos , Camundongos Endogâmicos C57BL , Suínos , Transplante Heterólogo , Fator de Necrose Tumoral alfa/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
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