RESUMEN
Glucagon-like peptide-1 (GLP-1) is a peripheral incretin and centrally active peptide produced in the intestine and nucleus tractus solitarii (NTS), respectively. GLP-1 not only regulates metabolism but also improves cognition and is neuroprotective. While intestinal GLP-1-producing cells have been well characterized, less is known about GLP-1-producing neurons in NTS. We hypothesized that obesity-induced type 2 diabetes (T2D) impairs the function of NTS GLP-1-producing neurons and glycemia normalization counteracts this effect. We used immunohistochemistry/quantitative microscopy to investigate the number, potential atrophy, and activation (cFos-expression based) of NTS GLP-1-producing neurons, in non-diabetic versus obese/T2D mice (after 12 months of high-fat diet). NTS neuroinflammation was also assessed. The same parameters were quantified in obese/T2D mice treated from month 9 to 12 with two unrelated anti-hyperglycemic drugs: the dipeptidyl peptidase-4 inhibitor linagliptin and the sulfonylurea glimepiride. We show no effect of T2D on the number and volume but increased activation of NTS GLP-1-producing neurons. This effect was partially normalized by both anti-diabetic treatments, concurrent with decreased neuroinflammation. Increased activation of NTS GLP-1-producing neurons could represent an aberrant metabolic demand in T2D/obesity, attenuated by glycemia normalization. Whether this effect represents a pathophysiological process preceding GLP-1 signaling impairment in the CNS, remains to be investigated.
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Diabetes Mellitus Tipo 2 , Péptido 1 Similar al Glucagón , Animales , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Dieta Alta en Grasa , Péptido 1 Similar al Glucagón/metabolismo , Ratones , Neuronas/metabolismo , Obesidad/tratamiento farmacológico , Núcleo Solitario/metabolismoRESUMEN
AIMS/HYPOTHESIS: ZBED6 (zinc finger, BED-type containing 6) is known to regulate muscle mass by suppression of Igf2 gene transcription. In insulin-producing cell lines, ZBED6 maintains proliferative capacity at the expense of differentiation and beta cell function. The aim was to study the impact of Zbed6 knockout on beta cell function and glucose tolerance in C57BL/6 mice. METHODS: Beta cell area and proliferation were determined in Zbed6 knockout mice using immunohistochemical analysis. Muscle and fat distribution were assessed using micro-computed tomography. Islet gene expression was assessed by RNA sequencing. Effects of a high-fat diet were analysed by glucose tolerance and insulin tolerance tests. ZBED6 was overexpressed in EndoC-ßH1 cells and human islet cells using an adenoviral vector. Beta cell cell-cycle analysis, insulin release and mitochondrial function were studied in vitro using propidium iodide staining and flow cytometry, ELISA, the Seahorse technique, and the fluorescent probes JC-1 and MitoSox. RESULTS: Islets from Zbed6 knockout mice showed lowered expression of the cell cycle gene Pttg1, decreased beta cell proliferation and decreased beta cell area, which occurred independently from ZBED6 effects on Igf2 gene expression. Zbed6 knockout mice, but not wild-type mice, developed glucose intolerance when given a high-fat diet. The high-fat diet Zbed6 knockout islets displayed upregulated expression of oxidative phosphorylation genes and genes associated with beta cell differentiation. In vitro, ZBED6 overexpression resulted in increased EndoC-ßH1 cell proliferation and a reduced glucose-stimulated insulin release in human islets. ZBED6 also reduced mitochondrial JC-1 J-aggregate formation, mitochondrial oxygen consumption rates (OCR) and mitochondrial reactive oxygen species (ROS) production, both at basal and palmitate + high glucose-stimulated conditions. ZBED6-induced inhibition of OCR was not rescued by IGF2 addition. ZBED6 reduced levels of the mitochondrial regulator PPAR-γ related coactivator 1 protein (PRC) and bound its promoter/enhancer region. Knockdown of PRC resulted in a lowered OCR. CONCLUSIONS/INTERPRETATION: It is concluded that ZBED6 is required for normal beta cell replication and also limits excessive beta cell mitochondrial activation in response to an increased functional demand. ZBED6 may act, at least in part, by restricting PRC-mediated mitochondrial activation/ROS production, which may lead to protection against beta cell dysfunction and glucose intolerance in vivo.
Asunto(s)
Dieta Alta en Grasa , Intolerancia a la Glucosa/metabolismo , Células Secretoras de Insulina/fisiología , Mitocondrias/metabolismo , Proteínas Represoras/fisiología , Adenoviridae/genética , Animales , Proliferación Celular , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Regulación de la Expresión Génica/fisiología , Vectores Genéticos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Consumo de Oxígeno/fisiología , Fosforilación , Especies Reactivas de Oxígeno , Reacción en Cadena en Tiempo Real de la Polimerasa , Securina/genéticaRESUMEN
BACKGROUND: Preclinical experiments show that an inflammatory reaction causes degradation of the endothelial glycocalyx layer and accelerated capillary leakage of albumin and fluid. The hypothesis in the present study was that elevated plasma concentrations of glycocalyx degradation products are associated with greater capillary leakage in humans. METHODS: This open clinical trial involved administration of an intravenous infusion of 20% albumin at 3 mL/kg over 30 minutes to 15 postburn patients who showed an activated inflammatory response. Blood samples and urine were collected for 300 minutes. The plasma concentrations of 2 biomarkers of glycocalyx degradation-syndecan-1 and heparan sulfate-were measured at 0, 60, and 300 minutes and compared to the capillary leakage of albumin and fluid obtained by mass balance calculations and population kinetic analysis. RESULTS: Patients were studied at 7 days (median) after a burn injury that covered 15% (maximum 48%) of the body surface area. The median plasma syndecan-1 concentration was 71 (25th-75th percentiles, 41-185) ng/mL. The 2 patients with highest values showed 2279 and 2395 ng/mL (normal 15 ng/mL). Heparan sulfate concentrations averaged 915 (673-1539) ng/mL. The infused amount of albumin was 57 (48-62) g, and 6.3 (5.1-7.7)% of that leaked from the plasma per hour.Linear correlation analysis of the relationship between the 10logarithm of the mean syndecan-1 and the albumin leakage showed a slope coefficient of -1.3 (95% confidence interval [CI], -3.6 to 1.0) and a correlation coefficient of -0.33 (P = .24). The kinetic analysis revealed that syndecan-1 served as a statistically significant covariate to the albumin leakage, but the relationship was inverse (power exponent -0.78, 95% CI, -1.50 to -0.05; P < .02). Heparan sulfate levels did not correlate with the capillary leakage of albumin or fluid in any of the analyses. CONCLUSIONS: A raised plasma concentration of syndecan-1 alone cannot be extrapolated to indicate increased capillary leakage of albumin and fluid.
Asunto(s)
Albúminas/administración & dosificación , Quemaduras/terapia , Permeabilidad Capilar , Células Endoteliales/metabolismo , Fluidoterapia , Glicocálix/metabolismo , Sindecano-1/sangre , Adulto , Anciano , Albúminas/efectos adversos , Biomarcadores/sangre , Quemaduras/sangre , Quemaduras/fisiopatología , Femenino , Fluidoterapia/efectos adversos , Heparitina Sulfato/sangre , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Suecia , Factores de Tiempo , Regulación hacia ArribaRESUMEN
BACKGROUND: The endothelial glycocalyx, a carbohydrate-rich layer coating all endothelial surfaces, plays a fundamental role in the function of microcirculation. The primary aim of this study was to evaluate the feasibility of using dexamethasone and albumin to protect the endothelial glycocalyx in patients undergoing abdominal surgery. Secondary and exploratory outcomes included efficacy and safety. METHODS: We conducted a multicenter, open-label, blinded end point, phase 2, randomized trial. Patients undergoing colorectal, pancreas, or liver surgery were recruited and randomized to receive either intravenous dexamethasone (16 mg) and 20% albumin (100 mL) at induction of anesthesia, then 200 mL of 20% albumin with each subsequent 1000 mL of crystalloid administered (dexamethasone and albumin [Dex-Alb] group), or crystalloid fluid only with no dexamethasone (control group). Feasibility end points included patient recruitment and retention, consent rate, and successful study drug administration. The primary efficacy end point was the measurement of plasma syndecan-1 level on postoperative day (POD) 1, and secondary end points were heparan sulfate levels and inflammatory markers measured at 4 perioperative timepoints. Safety end points included errors in administration of the intervention, hyperglycemia, occurrence of postoperative complications, and patient retention. RESULTS: Seventy-two patients were randomized. All feasibility end points were achievable. There were no statistically significant differences observed in median (interquartile range) syndecan-1 levels on POD 1 (39 ng·mL-1 [20-97] in the Dex-Alb group versus 41 ng·mL-1 [19-84] in the control group; difference in medians -2.1, 95% confidence interval [CI], -13 to 8.6; P = .69). The Dex-Alb group had lower POD 1 heparan sulfate levels (319 ng·mL-1 [161-717] in the Dex-Alb group versus 1422 [670-2430] ng·mL-1 in the control group; difference in medians -1085, 95% CI, -1779 to -391) and C-reactive protein (CRP) levels on POD 1 (48 [29-77] mg·L-1 in the Dex-Alb group versus 85 mg·L-1 [49-133] in the control group; difference in medians -48, 95% CI, -75 to -21). Fewer patients had one or more postoperative complication in the Dex-Alb group than in the control group (6 [17%] vs 18 patients [50%]; odds ratio = 0.2, 95% CI, 0.06-0.6). CONCLUSIONS: Intravenous dexamethasone and albumin administration was feasible but did not reduce syndecan-1 on POD 1 in patients undergoing abdominal surgery. Given the clinically important CIs observed between the groups for heparan sulfate, CRP, and postoperative complications, a larger trial assessing the associations between dexamethasone and albumin administration and these outcomes is warranted.
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Abdomen/cirugía , Albúminas/administración & dosificación , Soluciones Cristaloides/administración & dosificación , Dexametasona/administración & dosificación , Procedimientos Quirúrgicos del Sistema Digestivo , Endotelio Vascular/efectos de los fármacos , Glucocorticoides/administración & dosificación , Microvasos/efectos de los fármacos , Complicaciones Posoperatorias/prevención & control , Anciano , Albúminas/efectos adversos , Biomarcadores/sangre , Proteína C-Reactiva/metabolismo , Soluciones Cristaloides/efectos adversos , Dexametasona/efectos adversos , Procedimientos Quirúrgicos del Sistema Digestivo/efectos adversos , Endotelio Vascular/metabolismo , Estudios de Factibilidad , Femenino , Glucocorticoides/efectos adversos , Glicocálix/efectos de los fármacos , Glicocálix/metabolismo , Heparitina Sulfato/sangre , Humanos , Infusiones Intravenosas , Masculino , Microvasos/metabolismo , Persona de Mediana Edad , Nueva Zelanda , Complicaciones Posoperatorias/sangre , Complicaciones Posoperatorias/etiología , Cuidados Preoperatorios , Sindecano-1/sangre , Factores de Tiempo , Resultado del Tratamiento , VictoriaRESUMEN
The naturally occurring quassinoid compound brusatol improves the survival of insulin-producing cells when exposed to the proinflammatory cytokines IL-1ß and IFN-γ in vitro. The aim of the present study was to investigate whether brusatol also promotes beneficial effects in mice fed a high-fat diet (HFD), and if so, to study the mechanisms by which brusatol acts. In vivo, we observed that the impaired glucose tolerance of HFD-fed male C57BL/6 mice was counteracted by a 2 wk treatment with brusatol. Brusatol treatment improved both ß-cell function and peripheral insulin sensitivity of HFD-fed mice. In vitro, brusatol inhibited ß-cell total protein and proinsulin biosynthesis, with an ED50 of â¼40 nM. In line with this, brusatol blocked cytokine-induced iNOS protein expression via inhibition of iNOS mRNA translation. Brusatol may have affected protein synthesis, at least in part, via inhibition of eukaryotic initiation factor 5A (eIF5A) hypusination, as eIF5A spermidine association and hypusination in RIN-5AH cells was reduced in a dose- and time-dependent manner. The eIF5A hypusination inhibitor GC7 promoted a similar effect. Both brusatol and GC7 protected rat RIN-5AH cells against cytokine-induced cell death. Brusatol reduced eIF5A hypusination and cytokine-induced cell death in EndoC-ßH1 cells as well. Finally, hypusinated eIF5A was reduced in vivo by brusatol in islet endocrine and endothelial islet cells of mice fed an HFD. The results of the present study suggest that brusatol improves glucose intolerance in mice fed an HFD, possibly by inhibiting protein biosynthesis and eIF5A hypusination.-Turpaev, K., Krizhanovskii, C., Wang, X., Sargsyan, E., Bergsten, P., Welsh, N. The protein synthesis inhibitor brusatol normalizes high-fat diet-induced glucose intolerance in male C57BL/6 mice: role of translation factor eIF5A hypusination.
Asunto(s)
Dieta Alta en Grasa/efectos adversos , Intolerancia a la Glucosa/tratamiento farmacológico , Factores de Iniciación de Péptidos/metabolismo , Inhibidores de la Síntesis de la Proteína/farmacología , Cuassinas/farmacología , Proteínas de Unión al ARN/metabolismo , Animales , Muerte Celular/efectos de los fármacos , Citocinas/metabolismo , Intolerancia a la Glucosa/metabolismo , Células Secretoras de Insulina/efectos de los fármacos , Células Secretoras de Insulina/metabolismo , Islotes Pancreáticos/efectos de los fármacos , Islotes Pancreáticos/metabolismo , Lisina/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Óxido Nítrico Sintasa de Tipo II/metabolismo , Biosíntesis de Proteínas/efectos de los fármacos , Procesamiento Proteico-Postraduccional/fisiología , Factor 5A Eucariótico de Iniciación de TraducciónRESUMEN
BACKGROUND: Fluid-induced hypervolemia may stimulate the release of natriuretic peptides and cause degradation (shedding) of the endothelial glycocalyx layer. Sevoflurane is believed to protect the glycocalyx, but the importance of using sevoflurane to prevent shedding during routine surgery is unclear. METHODS: The plasma concentrations of brain natriuretic peptide and two biomarkers of glycocalyx shedding, syndecan-1, and heparan sulfate, were measured in 26 patients randomized to receive general anesthesia with sevoflurane or propofol during open abdominal hysterectomy. The fluid therapy consisted of 25 mL/kg (approximately 2 L) of Ringer´s lactate over 30 minutes. Blood hemoglobin and plasma albumin were used to indicate plasma volume expansion and capillary leakage. RESULTS: The plasma concentrations of brain natriuretic peptide and shedding products showed low levels throughout the surgery (median brain natriuretic peptide, 21 ng/L; syndecan-1, 12.9 ng/mL; and heparan sulfate, 6.5 µg/mL), but the heparan sulfate concentration increased 2 hours post-operatively (to 17.3 µg/mL, P < .005). No differences were noted between the propofol and sevoflurane groups in any of the measured parameters. Albumin was apparently recruited to the bloodstream during the first 20 minutes, when the intravascular retention of infused fluid was almost 100%. The urine flow was <1 mL/min, despite the vigorous volume loading. CONCLUSIONS: No relevant elevations of brain natriuretic peptide or degradation products of the glycocalyx layer were observed when hypervolemia was induced during open abdominal hysterectomy performed with sevoflurane or propofol anesthesia. Plasma volume expansion from Ringer´s lactate was pronounced.
Asunto(s)
Endotelio Vascular/metabolismo , Fluidoterapia/efectos adversos , Glicocálix/metabolismo , Histerectomía , Propofol/farmacología , Sevoflurano/farmacología , Adulto , Anestésicos por Inhalación/farmacología , Anestésicos Intravenosos/farmacología , Femenino , Fluidoterapia/métodos , Glicocálix/efectos de los fármacos , Heparitina Sulfato/sangre , Humanos , Letonia , Masculino , Persona de Mediana Edad , Péptido Natriurético Encefálico/sangre , Péptido Natriurético Encefálico/efectos de los fármacos , Lactato de Ringer/efectos adversos , Sindecano-1/sangre , Desequilibrio Hidroelectrolítico/complicacionesRESUMEN
BACKGROUND: Albumin may persist intravascularly for a shorter time in patients after major surgery than in healthy volunteers due to a surgery-induced breakdown (shedding) of the endothelial glycocalyx layer. METHODS: In this nonrandomized clinical trial, an IV infusion of 3 mL/kg of 20% albumin was given at a constant rate during 30 minutes to 15 patients on the first day after major open abdominal surgery (mean operating time 5.9 h) and to 15 conscious volunteers. Blood samples and urine were collected during 5 h and mass balance calculations used to estimate the half-lives of the administered albumin molecules and the induced plasma volume expansion, based on measurements of hemodilution and the plasma albumin concentration. RESULTS: At the end of the infusions, albumin had diluted the plasma volume by 13.3% ± 4.9% (mean ± SD) in the postoperative patients and by 14.2% ± 4.8% in the volunteers (mean difference -0.9, 95% CI, -4.7 to 2.9; 1-way ANOVA P = .61), which amounted to twice the infused volume. The intravascular half-life of the infused albumin molecules was 9.1 (5.7-11.2) h in the surgical patients and 6.0 (5.1-9.0) h in the volunteers (Mann-Whitney U test, P = .26; geometric mean difference 1.2, 95% CI, 0.8-2.0). The half-life of the plasma volume expansion was 10.3 (5.3-17.6; median and interquartile range) h in the surgical patients and 7.6 (3.5-9.0) h in the volunteers (P = .10; geometric mean difference 1.5, 95% CI, 0.8-2.8). All of these parameters correlated positively with the body mass index (correlation coefficients being 0.42-0.47) while age and sex did not affect the results. CONCLUSIONS: Twenty percent albumin caused a long-lasting plasma volume expansion of similar magnitude in postoperative patients and volunteers.
Asunto(s)
Albúminas/farmacocinética , Procedimientos Quirúrgicos Operativos , Abdomen/cirugía , Adulto , Anciano , Albúminas/administración & dosificación , Femenino , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Volumen Plasmático , Periodo PosoperatorioRESUMEN
BACKGROUND: Surgery with and without hypervolaemia may cause shedding (breakdown) of the endothelial glycocalyx layer, but the severity of this problem is unclear. METHODS: In this preliminary report of a larger clinical trial, the plasma and urine concentrations of three biomarkers of glycocalyx shedding (syndecan-1, hyaluronic acid and heparan sulfate) were measured in seven patients before, during, and after open hysterectomy. The fluid therapy consisted of 25 ml/kg (approximately 2 l) of Ringer's lactate, which was infused over 30 min when the surgery started. The resulting plasma volume expansion at the end of the infusion was estimated from the haemodilution. RESULTS: The mean plasma concentration of syndecan-1 was 21.7 ng/ml before surgery and averaged 19.7 ng/ml during and after the surgery. The plasma concentration of hyaluronic acid decreased from 38.0 to 27.7 ng/ml (P < 0.05), while heparan sulfate increased from 3.4 to 5.5 µg/ml (P < 0.05). The urine concentrations of syndecan-1 decreased significantly, while they increased for hyaluronic acid and heparan sulfate. Despite the vigorous fluid load, the urine flow did not exceed 1 ml/min. CONCLUSIONS: No clear evidence was found for shedding of the endothelial glycocalyx layer when 2 l of Ringer's lactate was infused over 30 min during abdominal hysterectomy. Urine analyses yielded patterns of changes that differed from those in plasma. TRIAL REGISTRATION: ISRCTN81005631 . Registered May 17, 2016.
Asunto(s)
Glicocálix/metabolismo , Heparitina Sulfato/sangre , Heparitina Sulfato/orina , Ácido Hialurónico/sangre , Ácido Hialurónico/orina , Histerectomía/efectos adversos , Sindecano-1/sangre , Sindecano-1/orina , Adulto , Biomarcadores/sangre , Femenino , Fluidoterapia/efectos adversos , Humanos , Persona de Mediana EdadRESUMEN
A reduced prevalence of a thoracic aortic aneurysm (thoracic AA) is observed in type 2 diabetes (T2D). Glucagon-like peptide-1 (GLP-1)/GLP-1-based anti-diabetic therapy has indicated protective effects in thoracic AA and regulates the processes controlling the vascular tissue expression of Syndecan-1 (Sdc-1). Sdc-1 expression on macrophages infiltrating the aortic tissue contributes to a counter-regulatory response to thoracic AA formation in animal models through the interplay with inflammation/proteolytic activity. We hypothesized that elevated fasting plasma GLP-1 (fpGLP-1) increases the aortic Sdc-1 expression in T2D, which may contribute to a reduced prevalence of thoracic AA. Consequently, we determined whether T2D/thoracic AA associates with an altered Sdc-1 expression in the aortic tissue and the possible associations with fpGLP-1 and inflammation/proteolytic activity. From a cohort of surgical patients with an aortic valve pathology, we compared different disease groups (T2D/thoracic AA) with the same sub-cohort group of controls (patients without T2D and thoracic AA). The MMP-2 activity and Sdc-1, GLP-1R and CD68 expression were analyzed in the aortic tissue. GLP-1, Sdc-1 and cytokines were analyzed in the plasma. The aortic Sdc-1 expression was increased in T2D patients but did not correlate with fpGLP-1. Thoracic AA was associated with an increased aortic expression of Sdc-1 and the macrophage marker CD68. CD68 was not detected in T2D. In conclusion, an increased aortic Sdc-1 expression may contribute to a reduced prevalence of thoracic AA in T2D.
RESUMEN
Glucagon-like peptide-1 (GLP-1) regulates processes involved in the pathophysiology of thoracic aortic aneurysms (TAAs), including inflammation, while protecting against aortic aneurysms in animal models. Type 2 diabetes (T2D) involves altered GLP-1 signaling due to pathology and/or therapy and is associated with reduced prevalence of TAAs. We aimed to assess whether T2D alters the inflammatory profile/proteolytic activity, possible correlations to elevated fasting GLP-1 (F-GLP-1), and its relevance for TAA. F-GLP-1, pro-inflammatory T helper 1 (Th1) cytokines, Th2 cytokines, C-reactive protein, and matrix metalloproteinase-2 activity (MMP-2) were analyzed in surgical patients with aortic valve pathology with/without T2D and without T2D but with TAA. Patients with T2D displayed an increase in the relative systemic expression of interleukin 6 and tumor necrosis factor α and a clear trend towards reduced levels of interferon γ (IFNγ). In addition, a positive association between GLP-1 and the plasma interleukin 4 (IL-4)/IFNγ ratio was detected. TAA was associated with significantly lower plasma levels of the Th2 cytokines IL-4 and interleukin 5. Plasma MMP-2 activity did not differ between groups. We conclude that T2D involved a Th2 shift, which associates with elevated F-GLP-1 and may-considering Th1 bias in TAA-contribute to reduced prevalence of TAA in T2D.
RESUMEN
The interplay between obesity and type 2 diabetes (T2D) in poststroke recovery is unclear. Moreover, the impact of glucose control during the chronic phase after stroke is undetermined. We investigated whether obesity-induced T2D impairs neurological recovery after stroke by using a clinically relevant experimental design. We also investigated the potential efficacy of two clinically used T2D drugs: the dipeptidyl peptidase 4 inhibitor linagliptin and the sulfonylurea glimepiride. We induced transient middle cerebral artery occlusion (tMCAO) in T2D/obese mice (after 7 months of high-fat diet [HFD]) and age-matched controls. After stroke, we replaced HFD with standard diet for 8 weeks to mimic the poststroke clinical situation. Linagliptin or glimepiride were administered daily from 3 days after tMCAO for 8 weeks. We assessed neurological recovery weekly by upper-limb grip strength. Brain damage, neuroinflammation, stroke-induced neurogenesis, and atrophy of parvalbumin-positive (PV+) interneurons were quantified by immunohistochemistry. T2D/obesity impaired poststroke neurological recovery in association with hyperglycemia, neuroinflammation, and atrophy of PV+ interneurons. Both drugs counteracted these effects. In nondiabetic mice, only linagliptin accelerated recovery. These findings shed light on the interplay between obesity and T2D in stroke recovery. Moreover, they promote the use of rehabilitative strategies that are based on efficacious glycemia regulation, even if initiated days after stroke.
Asunto(s)
Glucemia/análisis , Diabetes Mellitus Tipo 2/complicaciones , Infarto de la Arteria Cerebral Media/complicaciones , Obesidad/complicaciones , Recuperación de la Función/efectos de los fármacos , Accidente Cerebrovascular/complicaciones , Animales , Peso Corporal/efectos de los fármacos , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Dieta , Modelos Animales de Enfermedad , Hipoglucemiantes/farmacología , Hipoglucemiantes/uso terapéutico , Infarto de la Arteria Cerebral Media/sangre , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Linagliptina/farmacología , Linagliptina/uso terapéutico , Masculino , Ratones , Obesidad/sangre , Obesidad/tratamiento farmacológico , Accidente Cerebrovascular/sangre , Accidente Cerebrovascular/tratamiento farmacológico , Compuestos de Sulfonilurea/farmacología , Compuestos de Sulfonilurea/uso terapéutico , Resultado del TratamientoRESUMEN
Epidemiological evidence supports a reduced prevalence of Thoracic Aortic Aneurysm (TAA) and Abdominal Aortic Aneurysm (AAA) in patients with Diabetes (DM). The mechanisms underlying this negative association are unknown. Some studies support that hyperglycemia has effects on the Extracellular Matrix (ECM), resulting in collagen cross-links and altered proteolytic activity, which ultimately counteracts aneurysm formation. However, recent experimental research indicates that incretin- based anti-diabetic therapy and Glucagon-Like Peptide-1 (GLP-1) may reduce the formation of TAA. GLP-1 is a peptide hormone, released from intestinal L-cells in response to hormonal, neural and nutrient stimuli. In addition to potentiation of meal-stimulated insulin secretion, GLP-1 signaling exerts numerous pleiotropic effects on various tissues, including protective effects on the myocardium and vascular endothelium. Recent studies also report protective effects of GLP-1 based therapy on the formation of aneurysms in animal models and direct effects of GLP-1 signaling on the molecular mechanisms suggested to influence TAA formation, including inflammation, proteolytic activity and collagen composition. In this narrative review, we present the available evidence for effects of GLP-1 on experimental aneurysm development and discuss the potential role of GLP-1 in aneurysm formation based on available data from pre-clinical and clinical studies.
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Aorta Torácica/efectos de los fármacos , Aneurisma de la Aorta Torácica/prevención & control , Diabetes Mellitus/tratamiento farmacológico , Péptido 1 Similar al Glucagón/metabolismo , Receptor del Péptido 1 Similar al Glucagón/antagonistas & inhibidores , Hipoglucemiantes/uso terapéutico , Incretinas/uso terapéutico , Remodelación Vascular/efectos de los fármacos , Animales , Aorta Torácica/metabolismo , Aorta Torácica/patología , Aneurisma de la Aorta Torácica/epidemiología , Aneurisma de la Aorta Torácica/metabolismo , Aneurisma de la Aorta Torácica/patología , Diabetes Mellitus/epidemiología , Diabetes Mellitus/metabolismo , Diabetes Mellitus/patología , Receptor del Péptido 1 Similar al Glucagón/metabolismo , Humanos , Hipoglucemiantes/efectos adversos , Incretinas/efectos adversos , Factores de Riesgo , Transducción de Señal , Resultado del TratamientoRESUMEN
BACKGROUND: Fatty acids (FAs), and especially monounsaturated FAs (MUFAs) stimulate GLP-1 release. However, lipotoxicity is indicated in GLP-1 secreting cells following long-term exposure to elevated levels of saturated FAs (SFAs) in vivo and in vitro, where in vitro studies indicate that cosupplementation with MUFAs confers lipoprotection. SFAs and MUFAs differentially affect the fate of cells in ways that depend on the cell type, concentration and ratio of the FAs. The present study was designed to further elucidate the mechanisms underlying the effects of SFAs/MUFAs on GLP-1-producing cells in terms of lipotoxicity/lipoprotection and GLP-1 secretion. METHODS: Cultured GLP-1 secreting cells were exposed to hyperlipidemia simulated by SFA-albumin complexes where the molar ratio was 2:1. The cellular response to simulated hyperlipidemia was assessed in the presence/absence of MUFA cosupplementation by determining intracellular ceramide, ROS, neutral lipid accumulation, and cellular respiration. The role for cellular respiration in GLP-1 secretion in response to SFAs/MUFAs was assessed. RESULTS: Generation of intracellular ceramide mediate a detrimental increased in ROS production following long term exposure to SFAs in GLP-1-secreting cells. Cosupplementation with MUFAs increases cellular respiration, triglyceride synthesis, and the expression of ceramide kinase, while reducing ceramide synthesis and attenuating ROS production, caspase-3 activity and DNA fragmentation. Further, acute secretory effects of unsaturated FAs are independent of FAO, but mediated by a FFAR1 induced increase in cellular respiration. CONCLUSION: This study demonstrates novel data supporting effects of MUFAs on the ceramide biosynthetic pathway, triglyceride storage respiration and secretion in GLP-1 secreting cells. These findings may be of value for nutritional interventions, as well as for identification of novel targets, to help preserve L-cell mass and potentiate GLP-1 secretion in diabesity.
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Ceramidas/farmacocinética , Péptido 1 Similar al Glucagón/metabolismo , Hiperlipidemias/metabolismo , Ácido Oléico/farmacología , Especies Reactivas de Oxígeno/metabolismo , Animales , Línea Celular Tumoral , Humanos , Hiperlipidemias/patología , RatonesRESUMEN
BACKGROUND AND AIM: Fatty acids acutely stimulate GLP-1 secretion from L-cells in vivo. However, a high fat diet has been shown to reduce the density of L-cells in the mouse intestine and a positive correlation has been indicated between L-cell number and GLP-1 secretion. Thus, the mechanism of fatty acid-stimulated GLP-1 secretion, potential effects of long-term exposure to elevated levels of different fatty acid species, and underlying mechanisms are not fully understood. In the present study, we sought to determine how long-term exposure to saturated (16:0) and unsaturated (18:1) fatty acids, by direct effects on GLP-1-producing cells, alter function and viability, and the underlying mechanisms. METHODS: GLP-1-secreting GLUTag cells were cultured in the presence/absence of saturated (16:0) and unsaturated (18:1) fatty acids (0.125 mM for 48 h, followed by analyses of viability and apoptosis, as well as involvement of fatty acid oxidation, free fatty acid receptors (FFAR1) and ceramide synthesis. In addition, effects on the expression of proglucagon, prohormone convertase 1/3 (PC1/3), free fatty acid receptors (FFAR1, FFAR3), sodium glucose co-transporter (SGLT) and subsequent secretory response were determined. RESULTS: Saturated (16:0) and unsaturated (18:1) fatty acids exerted opposing effects on the induction of apoptosis (1.4-fold increase in DNA fragmentation by palmitate and a 0.5-fold reduction by oleate; p<0.01). Palmitate-induced apoptosis was associated with increased ceramide content and co-incubation with Fumonisin B1 abolished this lipo apoptosis. Oleate, on the other hand, reduced ceramide content, and-unlike palmitate-upregulated FFAR1 and FFAR3, evoking a 2-fold increase in FFAR1-mediated GLP-1 secretion following acute exposure to 0.125 mmol/L palmitate; (p<0.05). CONCLUSION/INTERPRETATION: Saturated (16:0), but not unsaturated (18:1), fatty acids induce ceramide-mediated apoptosis of GLP-1-producing cells. Further, unsaturated fatty acids confer lipoprotection, enhancing viability and function of GLP-1-secreting cells. These data provide potential mechanistic insight contributing to reduced L-cell mass following a high fat diet and differential effects of saturated and unsaturated fatty acids on GLP-1 secretion in vivo.
Asunto(s)
Ácidos Grasos Insaturados/metabolismo , Ácidos Grasos/metabolismo , Péptido 1 Similar al Glucagón/metabolismo , Animales , Caspasa 3/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Ceramidas/metabolismo , Ácidos Grasos/farmacología , Ácidos Grasos Insaturados/farmacología , Ratones , Ácido Oléico/farmacología , Especies Reactivas de Oxígeno/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
BACKGROUND: Diabetes is a risk factor for peripheral, coronary, and cerebrovascular disease. In contrast, results also indicate that patients with diabetes have reduced prevalence of aortic aneurysms, although the mechanisms remain largely unknown. We hypothesize that altered endogenous secretion of the intestinal hormone glucagon-like peptide-1 (GLP-1)-previously shown to protect from aneurysm formation, and governing many of the mechanisms thought to be involved in aneurysm formation-may provide insights into the mechanisms underlying the inverse relationship of diabetes and aneurysm. METHODS: We undertook a case-control study to characterize circulating plasma GLP-1 levels in diabetic and non-diabetic surgical patients with aortic valve disease, and with or without ascending aortic dilation. The cohort included patients with a bicuspid aortic valve (BAV), a common congenital disorder associated with ascending aortic aneurysm, as well as patients with a tricuspid aortic valve (TAV). RESULTS: In our patient group, diabetes was characterized by a significant increase in fasting plasma GLP-1 levels. Further, we show that aortic dilation in these patients was associated with a significant increase in fasting plasma GLP-1, although a significant increase in the intact and bioactive peptide could not be detected in BAV patients with aortic dilation. CONCLUSION: A subgroup of diabetic patients with aortic valve pathology have increased fasting plasma GLP-1 levels, which may be of importance for the low prevalence of aortic dilation in this patient group. Further, in TAV patients, GLP-1 secretion and plasma levels of intact GLP-1 are upregulated in association with aortic dilation, possibly indicating a compensatory mechanism.
RESUMEN
BACKGROUND: Enhanced IAPP production may contribute to islet amyloid formation in type 2 diabetes. The objective of this study was to determine the effects of the saturated fatty acid palmitate on IAPP levels in human ß-cells. METHODS: EndoC-ßH1 cells and human islets were cultured in the presence of sodium palmitate. Effects on IAPP/insulin mRNA expression and secretion were determined using real-time qPCR/ELISA. Pharmacological activators and/or inhibitors and RNAi were used to determine the underlying mechanisms. RESULTS: We observed that EndoC-ßH1 cells exposed to palmitate for 72 h displayed decreased expression of Pdx-1 and MafA and increased expression of thioredoxin-interacting protein (TXNIP), reduced insulin mRNA expression and glucose-induced insulin secretion, as well as increased IAPP mRNA expression and secretion. Further, these effects were independent of fatty acid oxidation, but abolished in response to GPR40 inhibition/downregulation. In human islets both a high glucose concentration and palmitate promoted increased IAPP mRNA levels, resulting in an augmented IAPP/insulin mRNA ratio. This was paralleled by elevated IAPP/insulin protein secretion and content ratios. CONCLUSIONS: Addition of exogenous palmitate to human ß-cells increased the IAPP/insulin expression ratio, an effect contributed to by activation of GPR40. These findings may be pertinent to our understanding of the islet amyloid formation process.
Asunto(s)
Insulina/metabolismo , Polipéptido Amiloide de los Islotes Pancreáticos/metabolismo , Ácido Palmítico/farmacología , ARN Mensajero/genética , Receptores Acoplados a Proteínas G/metabolismo , Animales , Línea Celular , Ácidos Grasos/metabolismo , Glucosa/metabolismo , Humanos , Insulina/genética , Polipéptido Amiloide de los Islotes Pancreáticos/genética , Islotes Pancreáticos/efectos de los fármacos , Islotes Pancreáticos/metabolismo , Ratones , Oxidación-Reducción , Proteína Quinasa C/metabolismo , Transducción de Señal , Factores de Transcripción/metabolismoRESUMEN
Aims - Human pancreatic islets are known to die in response to the free fatty acid of sodium palmitate when cultured in vitro. This is in contrast to EndoC-ßH1 cells, which in our hands are not sensitive to the cell death-inducing effects sodium palmitate, making these cells seemingly unsuitable for lipotoxicity studies. However, the EndoC-ßH1 cells are routinely cultured in a nutrient mixture based on Dulbecco's Modified Eagle Medium (DMEM), which may not be the optimal choice for studies dealing with lipotoxicity. The aim of the present investigation was to define culture conditions that render EndoC-ßH1 cells sensitive to toxic effects of sodium palmitate. Methods - EndoC-ßH1 cells were cultured at standard conditions in either DMEM or DMEM/F12 culture medium. Cell death was analyzed using propidium iodide staining and flow cytometry. Insulin release and content was quantified using a human insulin ELISA. Results - We presently observe that substitution of DMEM for a DMEM/Ham's F12 mixture (50%/50% vol/vol) renders the cells sensitive to the apoptotic effects of sodium palmitate and sodium palmitate + high glucose leading to an increased cell death. Supplementation of the DMEM culture medium with linoleic acid partially mimicked the effect of DMEM/F12. Culture of EndoC-ßH1 cells in DMEM/F12 resulted also in increased proliferation, ROS production and insulin contents, but markers for metabolic stress, autophagy or amyloid deposits were unaffected. Conclusions - The culture conditions for EndoC-ßH1 cells can be modified so these cells display signs of lipotoxicity in response to sodium palmitate.
Asunto(s)
Apoptosis/efectos de los fármacos , Medios de Cultivo/farmacología , Inhibidores Enzimáticos/farmacología , Células Secretoras de Insulina/efectos de los fármacos , Ácido Palmítico/farmacología , Proliferación Celular/efectos de los fármacos , Medios de Cultivo/química , Glucosa/farmacología , Humanos , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Ácido Linoleico/farmacología , Especies Reactivas de Oxígeno/metabolismoRESUMEN
OBJECTIVE: Renal conservation (retention) of fluid might affect the outcome of hospital care and can be indicated by increased urinary concentrations of metabolic waste products. We obtained a reference material for further studies by exploring the prevalence of fluid retention in a healthy population. METHODS: Spot urine sampling was performed in 300 healthy hospital workers. A previously validated algorithm summarized the urine-specific gravity, osmolality, creatinine, and color to a fluid retention index (FRI), where 4.0 is the cut-off for fluid retention consistent with dehydration. In 50 of the volunteers, we also studied the relationships between FRI, plasma osmolality, and water-retaining hormones. RESULTS: The cut-off for fluid retention (FRI ≥ 4.0) was reached by 38% of the population. No correlation was found between the FRI and the time of the day of urine sample collection, and the FRI was only marginally correlated with the time period spent without fluid intake. Volunteers with fluid retention were younger, generally men, and more often had albuminuria (88% vs. 34%, P < 0.001). Plasma osmolality and plasma sodium were somewhat higher in those with a high FRI (mean 294.8 vs. 293.4 mosmol/kg and 140.3 vs. 139.9 mmol/l). Plasma vasopressin was consistently below the limit of detection, and the plasma cortisol, aldosterone, and renin concentrations were similar in subjects with a high or low FRI. The very highest FRI values (≥ 5.0, N = 61) were always accompanied by albuminuria. CONCLUSION: Fluid retention consistent with moderate dehydration is common in healthy staff working in a Swedish hospital.