RESUMEN
Membrane interactions are critical for the successful use of inorganic nanoparticles as antimicrobial agents and as carriers of, or co-actives with, antimicrobial peptides (AMPs). In order to contribute to an increased understanding of these, we here investigate effects of particle size (42-208 nm) on layered double hydroxide (LDH) interactions with both bacteria-mimicking and mammalian-mimicking lipid membranes. LDH binding to bacteria-mimicking membranes, extraction of anionic lipids, as well as resulting membrane destabilization, was found to increase with decreasing particle size, also translating into size-dependent synergistic effects with the antimicrobial peptide LL-37. Due to strong interactions with anionic lipopolysaccharide and peptidoglycan layers, direct membrane disruption of both Gram-negative and Gram-positive bacteria is suppressed. However, LDH nanoparticles cause size-dependent charge reversal and resulting flocculation of both liposomes and bacteria, which may provide a mechanism for bacterial confinement or clearance. Taken together, these findings demonstrate a set of previously unknown behaviors, including synergistic membrane destabilization and dual confinement/killing of bacteria through combined LDH/AMP exposure, of potential therapeutic interest.
Asunto(s)
Antiinfecciosos/farmacocinética , Lipopolisacáridos , Nanopartículas , Péptidos/farmacocinética , Antiinfecciosos/química , Bacterias Grampositivas/efectos de los fármacos , Hidróxidos , Liposomas , Lípidos de la Membrana , Pruebas de Sensibilidad Microbiana , Tamaño de la Partícula , Péptidos/químicaRESUMEN
The integrity of the vasculature plays an important role in the success of allogeneic organ and haematopoietic stem cell transplantation. Endothelial cells (EC) have previously been shown to be the target of activated cytotoxic T lymphocytes (CTL) resulting in extensive cell lysis. Mesenchymal stromal cells (MSC) are multipotent cells which can be isolated from multiple sites, each demonstrating immunomodulatory capabilities. They are explored herein for their potential to protect EC from CTL-targeted lysis. CD8(+) T cells isolated from human PBMC were stimulated with mitotically inactive cells of a human microvascular endothelial cell line (CDC/EU.HMEC-1, further referred to as HMEC) for 7 days. Target HMEC were cultured in the presence or absence of MSC for 24 h before exposure to activated allogeneic CTL for 4 h. EC were then analysed for cytotoxic lysis by flow cytometry. Culture of HMEC with MSC in the efferent immune phase (24 h before the assay) led to a decrease in HMEC lysis. This lysis was determined to be MHC Class I restricted linked and further analysis suggested that MSC contact is important in abrogation of lysis, as protection is reduced where MSC are separated in transwell experiments. The efficacy of multiple sources of MSC was also confirmed, and the collaborative effect of MSC and the endothelium protective drug defibrotide were determined, with defibrotide enhancing the protection provided by MSC. These results support the use of MSC as an adjuvant cellular therapeutic in transplant medicine, alone or in conjunction with EC protective agents such as defibrotide.
Asunto(s)
Citotoxicidad Inmunológica , Células Endoteliales/inmunología , Células Madre Mesenquimatosas/inmunología , Factores Protectores , Linfocitos T Citotóxicos/inmunología , Comunicación Celular/efectos de los fármacos , Línea Celular , Técnicas de Cocultivo , Células Endoteliales/citología , Células Endoteliales/efectos de los fármacos , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/efectos de los fármacos , Polidesoxirribonucleótidos/farmacología , Cultivo Primario de Células , Sustancias Protectoras/farmacología , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/efectos de los fármacosRESUMEN
AIMS: To examine the incremental usefulness of adding alanine aminotransferase to established risk factors for predicting future diabetes. METHODS: The study population of the Insulin Resistance Atherosclerosis Study included 724 people aged 40-69 years. We excluded people who had excessive alcohol intake or were treated with lipid-lowering agents. Incident diabetes was assessed after a mean follow-up period of 5.2 years. RESULTS: Alanine aminotransferase had a non-linear relationship with incident diabetes (Wald chi-squared test, P < 0.001; P for linearity = 0.005) independent of demographic variables, family history of diabetes, BMI and fasting glucose; therefore, we used Youden's J statistic to dichotomize alanine aminotransferase [threshold ≥ 0.43 µkat/L ( ≥ 26 IU/l)]. Dichotomized alanine aminotransferase increased the area under the receiver-operating characteristic curve (0.805 vs. 0.823; P = 0.007) of a model that included demographic variables, family history of diabetes, BMI and fasting glucose as independent variables. The net reclassification improvement was 9.6% (95% CI 1.8-17.4; P = 0.016), and the integrated discrimination improvement was 0.031 (95% CI 0.011-0.050; P = 0.002). Dichotomized alanine aminotransferase reclassified a net of 9.6% of individuals more appropriately. CONCLUSIONS: Alanine aminotransferase may be useful for classifying individuals who are at risk of future diabetes after accounting for the effect of other risk factors, including family history, adiposity and plasma glucose.
Asunto(s)
Alanina Transaminasa/sangre , Aterosclerosis , Diabetes Mellitus Tipo 2/diagnóstico , Resistencia a la Insulina , Adulto , Anciano , Aterosclerosis/sangre , Aterosclerosis/complicaciones , Aterosclerosis/epidemiología , Estudios de Cohortes , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/epidemiología , Ayuno/sangre , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Resistencia a la Insulina/fisiología , Masculino , Persona de Mediana Edad , Obesidad/sangre , Obesidad/complicaciones , Obesidad/epidemiología , Valor Predictivo de las Pruebas , PronósticoRESUMEN
AIMS: To investigate whether the degree of albuminuria reduction observed in the ALTITUDE trial is associated with renal and cardiovascular protection, and secondly, whether the reduction in albuminuria was too small to afford clinical benefit. METHODS: In a post hoc analysis of the ALTITUDE trial in 8561 patients with type 2 diabetes and chronic kidney disease or cardiovascular disease we examined the effect of albuminuria changes at 6 months on renal and cardiovascular outcomes using Cox proportional hazard regression. RESULTS: The median change in albuminuria in the first 6 months in the aliskiren arm of the trial was -12% (25th to 75th percentile: -48.7_to_ +41.9%) and 0.0% (25th to 75th percentile: -40.2_to_55%) in the placebo arm. Changes in albuminuria in the first 6 months were linearly associated with renal and cardiovascular endpoints: a >30% reduction in albuminuria in the first 6 months was associated with a 62% reduction in renal risk and a 25% reduction in cardiovascular risk compared with an increase in albuminuria. The association between changes at 6 months in albuminuria and renal or cardiovascular endpoints was similar in the two treatment groups (p for interaction >0.1 for both endpoints). CONCLUSIONS: The addition of aliskiren to angiotensin-converting enzyme inhibitor/angiotensin receptor blocker therapy resulted in albuminuria changes that were associated with renal and cardiovascular risk changes. This did not translate into renal or cardiovascular protection because the overall reduction in albuminuria in the aliskiren arm was too small and nearly similar to that in the placebo arm.
Asunto(s)
Albuminuria/prevención & control , Antihipertensivos/uso terapéutico , Enfermedades Cardiovasculares/prevención & control , Diabetes Mellitus Tipo 2/complicaciones , Hipertensión/tratamiento farmacológico , Insuficiencia Renal Crónica/prevención & control , Renina/antagonistas & inhibidores , Anciano , Albuminuria/complicaciones , Albuminuria/epidemiología , Amidas/uso terapéutico , Antagonistas de Receptores de Angiotensina/uso terapéutico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Biomarcadores/orina , Enfermedades Cardiovasculares/complicaciones , Enfermedades Cardiovasculares/epidemiología , Estudios de Cohortes , Método Doble Ciego , Quimioterapia Combinada , Femenino , Estudios de Seguimiento , Fumaratos/uso terapéutico , Humanos , Hipertensión/complicaciones , Hipertensión/orina , Masculino , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto , Insuficiencia Renal Crónica/complicaciones , Insuficiencia Renal Crónica/epidemiología , Factores de RiesgoRESUMEN
OBJECTIVES: To examine the specific distribution of liver fat content, visceral and subcutaneous adiposity in normal glucose tolerance (NGT/NGT), isolated impaired fasting glucose (iIFG), isolated impaired glucose tolerance (iIGT) and combined conditions (IFG+IGT), as well as with newly diagnosed type 2 diabetes (nT2D). DESIGN: Multicenter, international observational study: cross-sectional analysis. SUBJECTS: Two thousand five hundred and fifteen patients (50.0% women, 54.5% non-Caucasian) without previously known diabetes were recruited from 29 countries. Abdominal fat distribution was measured by computed tomography (CT). Liver fat was estimated using the CT-liver mean attenuation. RESULTS: Compared with NGT/NGT patients, increased visceral adiposity was found in iIFG, iIGT, IFG+IGT and nT2D; estimated liver fat progressively increased across these conditions. A one-s.d. increase in visceral adiposity was associated with an increased risk of having iIFG (men: odds ratio (OR) 1.41 (95% confidence interval (CI) 1.15-1.74), women: OR 1.62 (1.29-2.04)), iIGT (men: OR 1.59 (1.15-2.01), women: OR 1.30 (0.96-1.76)), IFG+IGT (men: OR 1.64 (1.27-2.13), women: OR 1.83 (1.36-2.48)) and nT2D (men: OR 1.80 (1.35-2.42), women: OR 1.73 (1.25-2.41)). A one-s.d. increase in estimated liver fat was associated with iIGT (men: OR 1.46 (1.12-1.90), women: OR 1.81 (1.41-2.35)), IFG+IGT (men: OR 1.42 (1.14-1.77), women: OR 1.74 (1.35-2.26)) and nT2D (men: OR 1.77 (1.40-2.27), women: OR 2.38 (1.81-3.18)). Subcutaneous abdominal adipose tissue showed an inverse relationship with nT2D in women (OR 0.63 (0.45-0.88)). CONCLUSIONS: Liver fat was associated with iIGT but not with iIFG, whereas visceral adiposity was associated with both. Liver fat and visceral adiposity were associated with nT2D, whereas subcutaneous adiposity showed an inverse relationship with nT2D in women.
Asunto(s)
Glucemia/metabolismo , Intolerancia a la Glucosa/metabolismo , Grasa Intraabdominal/metabolismo , Hígado/metabolismo , Estado Prediabético/metabolismo , Índice de Masa Corporal , Estudios Transversales , Ayuno , Femenino , Intolerancia a la Glucosa/sangre , Prueba de Tolerancia a la Glucosa , Humanos , Resistencia a la Insulina , Masculino , Persona de Mediana Edad , Estado Prediabético/sangre , Valor Predictivo de las PruebasRESUMEN
AIM: To investigate whether previous physical activity levels are associated with blood glucose levels in individuals with impaired glucose tolerance in the context of an international pharmaceutical trial. METHODS: Data were analysed from the NAVIGATOR trial, which involved 9306 individuals with impaired glucose tolerance and high cardiovascular risk from 40 different countries, recruited in the period 2002-2004. Fasting glucose, 2-h post-challenge glucose and physical activity (pedometer) were assessed annually. A longitudinal regression analysis was used to determine whether physical activity levels 2 years (t-2 ) and 1 year (t-1 ) previously were associated with levels of glucose, after adjusting for previous glucose levels and other patient characteristics. Those participants with four consecutive annual measures of glucose and two consecutive measures of physical activity were included in the analysis. RESULTS: The analysis included 3964 individuals. Change in physical activity from t-2 to t-1 and activity levels at t-2 were both associated with 2-h glucose levels after adjustment for previous glucose levels and baseline characteristics; however, the associations were weak: a 100% increase in physical activity was associated with a 0.9% reduction in 2-h glucose levels. In addition, previous physical activity only explained an additional 0.05% of the variance in 2-h glucose over the variance explained by the history of 2-h glucose alone (R(2) = 0.3473 vs. 0.3468). There was no association with fasting glucose. CONCLUSIONS: In the context of a large international clinical trial, previous physical activity levels did not meaningfully influence glucose levels in those with a high risk of chronic disease, after taking into account participants' previous trajectory of glucose control.
Asunto(s)
Glucemia/metabolismo , Ayuno , Intolerancia a la Glucosa/metabolismo , Actividad Motora , Conducta de Reducción del Riesgo , Acelerometría , Actigrafía , Anciano , Bloqueadores del Receptor Tipo 1 de Angiotensina II/uso terapéutico , Enfermedades Cardiovasculares , Estudios de Cohortes , Ciclohexanos/uso terapéutico , Femenino , Intolerancia a la Glucosa/tratamiento farmacológico , Prueba de Tolerancia a la Glucosa , Humanos , Hipoglucemiantes/uso terapéutico , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Nateglinida , Fenilalanina/análogos & derivados , Fenilalanina/uso terapéutico , Estudios Prospectivos , Análisis de Regresión , Factores de Riesgo , Valsartán/uso terapéuticoRESUMEN
BACKGROUND: Coffee consumption has been associated with reduced risk of developing type 2 diabetes mellitus (T2DM) however, the mechanism for this association has yet to be elucidated. Non-alcoholic fatty liver disease (NAFLD) characterizes and predicts T2DM yet the relationship of coffee with this disorder remains unclear. Our aim was to investigate the associations of coffee with markers of liver injury in 1005 multi-ethnic, non-diabetic adults in the Insulin Resistance Atherosclerosis Study. METHODS: Dietary intake was assessed using a validated 114-item food frequency questionnaire. Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and fetuin-A were determined in fasting blood samples and the validated NAFLD liver fat score was calculated. Multivariate linear regression assessed the contribution of coffee to variation in markers of liver injury. RESULTS: Caffeinated coffee showed significant inverse associations with ALT (ß = -0.08, p = 0.0111), AST (ß = -0.05, p = 0.0155) and NAFLD liver fat score (ß = -0.05, p = 0.0293) but not with fetuin-A (ß = 0.04, p = 0.17). When the highest alcohol consumers were excluded, these associations remained (ALT ß = -0.11, p = 0.0037; AST ß = -0.05, p = 0.0330; NAFLD liver fat score ß = -0.06, p = 0.0298). With additional adjustment for insulin sensitivity, the relationship with ALT remained significant (ALT ß = -0.08, p = 0.0400; AST ß = -0.03, p = 0.20; NAFLD liver fat score ß = -0.03, p = 0.27). There were no significant associations of decaffeinated coffee with liver markers. CONCLUSIONS: These analyses indicate a beneficial impact of caffeinated coffee on liver morphology and/or function, and suggest that this relationship may mediate the well-established inverse association of coffee with risk of T2DM.
Asunto(s)
Alanina Transaminasa/sangre , Aspartato Aminotransferasas/sangre , Café , Diabetes Mellitus Tipo 2 , Hígado/patología , alfa-2-Glicoproteína-HS/metabolismo , Biomarcadores/sangre , Cafeína , Diabetes Mellitus Tipo 2/sangre , Femenino , Humanos , Resistencia a la Insulina , Modelos Lineales , Pruebas de Función Hepática , Masculino , Persona de Mediana Edad , Enfermedad del Hígado Graso no Alcohólico/sangre , Factores Protectores , Encuestas y CuestionariosRESUMEN
Increased physical activity is known to be beneficial in people with type 2 diabetes mellitus (T2DM), but it is not known whether individuals change their activity levels after T2DM diagnosis. The present Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial, conducted in participants with impaired glucose tolerance at high cardiovascular risk, assessed ambulatory activity annually using research-grade pedometers. Oral glucose tolerance tests were performed annually and repeated to confirm T2DM diagnosis. This observational analysis used general linear models to compare step counts before and after T2DM diagnosis in the 2816 participants with the requisite data. Participants were relatively inactive at baseline, taking a median (interquartile range) of 5488 (3258-8361) steps/day, which decreased after T2DM diagnosis by a mean (s.e.) of 258 (64) steps/day (p < 0.0001); however, after adjusting for background trend for activity, step count after T2DM diagnosis was unchanged [mean (s.e.) of 103 (87) fewer steps/day; p = 0.23]. Awareness of T2DM diagnosis had no impact on the trajectory of activity established before the diagnosis.
Asunto(s)
Actigrafía , Enfermedades Cardiovasculares/prevención & control , Diabetes Mellitus Tipo 2/psicología , Angiopatías Diabéticas/prevención & control , Monitoreo Ambulatorio , Actividad Motora , Conducta de Reducción del Riesgo , Caminata , Actigrafía/instrumentación , Glucemia/metabolismo , Presión Sanguínea , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/terapia , Progresión de la Enfermedad , Ejercicio Físico , Femenino , Prueba de Tolerancia a la Glucosa , Conocimientos, Actitudes y Práctica en Salud , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Ambulatorio/instrumentación , Cooperación del Paciente , Educación del Paciente como Asunto , Factores de RiesgoRESUMEN
AIMS/HYPOTHESIS: Markers of liver injury, such as alanine aminotransferase (ALT), have been associated with atherogenic lipoprotein changes. We examined the extent to which this association was explained by insulin resistance, adiposity, glucose tolerance and chronic inflammation. METHODS: In this analysis we included 824 non-diabetic participants (age 40-69 years) in the Insulin Resistance Atherosclerosis Study. No participants reported excessive alcohol intake or treatment with lipid-lowering medications. Lipoproteins and apolipoproteins were measured by conventional methods and lipoprotein heterogeneity by nuclear magnetic resonance (NMR) spectroscopy. RESULTS: ALT had a positive relationship with triacylglycerols, LDL-to-HDL-cholesterol ratio and apolipoprotein B (ApoB) after adjusting for demographic variables (p < 0.001 for all three relationships). ALT was also associated with the following NMR lipoproteins: positively with large VLDL (p < 0.001), intermediate-density lipoprotein (IDL) (p < 0.001) and small LDL subclass particles (p < 0.001), and VLDL particle size (p < 0.001); and negatively with large LDL subclass particles (p < 0.05) and LDL (p < 0.001) and HDL particle sizes (p < 0.01). ALT remained associated with IDL and small LDL subclass particles and ApoB after adjusting for glucose tolerance, adiposity, directly measured insulin sensitivity and C-reactive protein. CONCLUSIONS/INTERPRETATION: ALT is associated with a wide range of atherogenic lipoprotein changes, which are partially explained by insulin resistance, adiposity, glucose tolerance and chronic inflammation. Because of the significant variability in the relationship between ALT and liver fat, further studies are needed to assess the extent of the lipoprotein changes using a direct measure of liver fat.
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Alanina Transaminasa/sangre , Apolipoproteínas/sangre , Aterosclerosis/sangre , Aterosclerosis/metabolismo , Resistencia a la Insulina , Lipoproteínas/sangre , Adiposidad , Adulto , Anciano , Aterosclerosis/etnología , Enfermedad Crónica , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Inflamación , Espectroscopía de Resonancia Magnética , Masculino , Persona de Mediana Edad , Análisis de RegresiónRESUMEN
AIMS/HYPOTHESIS: Insulin clearance may decline as an early mechanism compensating for deteriorating insulin sensitivity. However, no previous studies have investigated the association between subclinical inflammation or impaired fibrinolysis and insulin clearance. We examined the association between plasminogen activator inhibitor (PAI)-1, C-reactive protein (CRP), TNF-α, leptin and fibrinogen and the progression of metabolic clearance rate of insulin (MCRI) over time. METHODS: We studied 784 non-diabetic white, Hispanic and African-American individuals in the Insulin Resistance Atherosclerosis Study (IRAS). Insulin sensitivity, acute insulin response and MCRI were determined from frequently sampled intravenous glucose tolerance tests at baseline and at 5-year follow-up. Inflammatory and fibrinolytic proteins were measured in fasting plasma at baseline. RESULTS: MCRI had declined significantly by 29% at the 5-year follow-up. We observed a significant association between higher plasma PAI-1 levels and the decline in MCRI in multivariable-adjusted regression models (ß = -0.045 [95% CI -0.081, -0.0091]). Higher plasma CRP and leptin levels were associated with a decline in MCRI in unadjusted models, but these associations were non-significant after adjusting for BMI and waist circumference (ß = -0.016 [95% CI -0.041, 0.0083] for CRP; ß = -0.044 [95% CI -0.10, 0.011] for leptin). A higher plasma TNF-α concentration was associated with a decline in MCRI in unadjusted (ß = -0.071 [95% CI -0.14, -0.00087]) but not in multivariable-adjusted (ß = -0.056 [95% CI -0.13, 0.017]) models. Plasma fibrinogen level was not associated with the change in MCRI. CONCLUSIONS/INTERPRETATION: We identified that higher plasma PAI-1 (but not CRP, TNF-α, leptin or fibrinogen) levels independently predicted the progressive decline of insulin clearance in the multiethnic cohort of the IRAS.
Asunto(s)
Aterosclerosis/etiología , Hipoglucemiantes/farmacocinética , Resistencia a la Insulina , Insulina/farmacocinética , Sobrepeso/fisiopatología , Inhibidor 1 de Activador Plasminogénico/sangre , Estado Prediabético/etiología , Aterosclerosis/epidemiología , Índice de Masa Corporal , Estudios de Cohortes , Angiopatías Diabéticas/sangre , Angiopatías Diabéticas/epidemiología , Angiopatías Diabéticas/inmunología , Angiopatías Diabéticas/metabolismo , Femenino , Fibrinógeno/análisis , Estudios de Seguimiento , Humanos , Hipoglucemiantes/sangre , Mediadores de Inflamación/sangre , Insulina/sangre , Leptina/sangre , Masculino , Tasa de Depuración Metabólica , Persona de Mediana Edad , Sobrepeso/sangre , Sobrepeso/inmunología , Sobrepeso/metabolismo , Estado Prediabético/epidemiología , Estudios Prospectivos , Factores de Riesgo , Estados Unidos/epidemiologíaRESUMEN
AIM: Visceral adipose tissue (VAT) and liver fat (LF) are strongly associated with type 2 diabetes. It is not known, however, how diabetes treatment and/or risk factor management modulates the association between VAT, LF and diabetes. The aim was to determine the level of VAT and LF in patients with type 2 diabetes according to their treatment status and achievement of the American Diabetes Association's (ADA) diabetes management goals. METHODS: We performed a cross-sectional analysis of the baseline data of the International Study of the Prediction of Intra-Abdominal Adiposity and its Relationship with Cardiometabolic risk/Intra-Abdominal Adiposity (INSPIRE ME IAA), a 3-year prospective cardiometabolic imaging study conducted in 29 countries. Patients (n = 3991) were divided into four groups: (i) those without type 2 diabetes (noT2D n = 1003 men, n = 1027 women); (ii) those with type 2 diabetes but not treated with diabetes medications (T2Dnomeds n = 248 men, n = 198 women); (iii) those with type 2 diabetes and treated with diabetes medications but not yet using insulin (T2Dmeds-ins n = 591 men, n = 484 women) and (iv) those with type 2 diabetes and treated with insulin (T2Dmeds+ins n = 233 men, n = 207 women). Abdominal and liver adiposity were measured by computed tomography. RESULTS: Fewer patients with high VAT or LF achieved the ADA's goals for high-density lipoprotein cholesterol (HDL-C) or triglycerides compared to patients with low VAT or LF. Visceral adiposity (p = 0.02 men, p = 0.003 women) and LF (p = 0.0002 men, p = 0.0004 women) increased among patients who met fewer of the ADA treatment criteria, regardless of type 2 diabetes treatment. CONCLUSION: Residual cardiometabolic risk exists among patients with type 2 diabetes characterized by elevated VAT and LF.
Asunto(s)
Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Insulina/uso terapéutico , Síndrome Metabólico/prevención & control , Adiposidad , Adulto , Anciano , Estudios de Cohortes , Terapia Combinada , Estudios Transversales , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/patología , Diabetes Mellitus Tipo 2/terapia , Quimioterapia Combinada , Femenino , Humanos , Hiperlipidemias/etiología , Hiperlipidemias/prevención & control , Grasa Intraabdominal/diagnóstico por imagen , Grasa Intraabdominal/patología , Metabolismo de los Lípidos , Hígado/diagnóstico por imagen , Hígado/patología , Masculino , Cumplimiento de la Medicación , Síndrome Metabólico/epidemiología , Síndrome Metabólico/fisiopatología , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto , Radiografía , Factores de RiesgoRESUMEN
AIMS: Cross-sectional evidence indicates that abdominal adiposity, hypertension, dyslipidaemia and glycaemia are associated with reduced metabolic clearance rate of insulin (MCRI). Little is known about the progression of MCRI and whether components of metabolic syndrome are associated with the change in MCRI. In this study, we examined the association between components of metabolic syndrome and the 5-year change of MCRI. METHODS: At baseline and 5-year follow-up, we measured fasting plasma triglycerides (TG), high-density lipoprotein (HDL) cholesterol, blood pressure (BP), waist circumference (WC) and fasting blood glucose (FBG) in 784 non-diabetic participants in the Insulin Resistance Atherosclerosis Study. MCRI, insulin sensitivity (SI ) and acute insulin response (AIR) were determined from frequently sampled intravenous glucose tolerance tests. RESULTS: We observed a 29% decline of MCRI at follow-up. TG, systolic BP and WC at baseline were inversely associated with a decline of MCRI regression models adjusted for age, sex, ethnicity, smoking, alcohol consumption, energy expenditure, family history of diabetes, BMI, SI and AIR [ß = -0.057 (95% confidence interval, CI: -0.11, -0.0084) for TG, ß = -0.0019 (95% CI: -0.0035, -0.00023) for systolic BP and ß = -0.0084 (95% CI: -0.013, -0.0039) for WC; all p < 0.05]. Higher HDL cholesterol at baseline was associated with an increase in MCRI [multivariable-adjusted ß = 0.0029 (95% CI: 0.0010, 0.0048), p = 0.002]. FBG at baseline was not associated with MCRI at follow-up [multivariable-adjusted ß = 0.0014 (95% CI: -0.0026, 0.0029)]. CONCLUSIONS: MCRI declined progressively over 5 years in a non-diabetic cohort. Components of metabolic syndrome at baseline were associated with a significant change in MCRI.
Asunto(s)
Aterosclerosis/sangre , HDL-Colesterol/sangre , Resistencia a la Insulina , Insulina/sangre , Síndrome Metabólico/sangre , Triglicéridos/sangre , Adiposidad , Adulto , Anciano , Aterosclerosis/epidemiología , Aterosclerosis/metabolismo , Biomarcadores/sangre , Glucemia/metabolismo , Presión Sanguínea , Índice de Masa Corporal , Estudios Transversales , Progresión de la Enfermedad , Dislipidemias/sangre , Femenino , Estudios de Seguimiento , Prueba de Tolerancia a la Glucosa , Hemoglobina Glucada/metabolismo , Humanos , Masculino , Tasa de Depuración Metabólica , Síndrome Metabólico/epidemiología , Síndrome Metabólico/metabolismo , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Factores de Riesgo , Estados Unidos/epidemiología , Circunferencia de la CinturaRESUMEN
BACKGROUND AND AIMS: Previous research on the association between fish consumption and incident type 2 diabetes has been inconclusive. In addition, few studies have investigated how fish consumption may be related to the metabolic abnormalities underlying diabetes. Therefore, we examined the association of fish consumption with measures of insulin sensitivity and beta-cell function in a multi-ethnic population. METHODS AND RESULTS: We examined the cross-sectional association between fish consumption and measures of insulin sensitivity and secretion in 951 non-diabetic participants in the Insulin Resistance Atherosclerosis Study (IRAS). Fish consumption, categorized as <2 vs. ≥2 portions/week, was measured using a validated food frequency questionnaire. Insulin sensitivity (S(I)) and acute insulin response (AIR) were determined from frequently sampled intravenous glucose tolerance tests. Higher fish consumption was independently associated with lower S(I)-adjusted AIR (ß = -0.13 [-0.25, -0.016], p = 0.03, comparing ≥2 vs. <2 portions/week). Fish consumption was positively associated with intact and split proinsulin/C-peptide ratios, however, these associations were confounded by ethnicity (multivariable-adjusted ß = 0.073 [-0.014, 0.16] for intact proinsulin/C-peptide ratio, ß = 0.031 [-0.065, 0.13] for split proinsulin/C-peptide ratio). We also observed a significant positive association between fish consumption and fasting blood glucose (multivariable-adjusted ß = 2.27 [0.68, 3.86], p = 0.005). We found no association between fish consumption and S(I) (multivariable-adjusted ß = -0.015 [-0.083, 0.053]) or fasting insulin (multivariable-adjusted ß = 0.016 [-0.066, 0.10]). CONCLUSIONS: Fish consumption was not associated with measures of insulin sensitivity in the multi-ethnic IRAS cohort. However, higher fish consumption may be associated with pancreatic beta-cell dysfunction.
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Aterosclerosis/sangre , Dieta , Resistencia a la Insulina , Células Secretoras de Insulina/fisiología , Carne , Adulto , Anciano , Animales , Glucemia/metabolismo , Péptido C/sangre , Estudios de Cohortes , Estudios Transversales , Diabetes Mellitus Tipo 2/sangre , Femenino , Peces , Prueba de Tolerancia a la Glucosa , Humanos , Insulina/sangre , Modelos Lineales , Masculino , Persona de Mediana Edad , Análisis Multivariante , Encuestas y CuestionariosRESUMEN
AIMS: The Insulinogenic Index from 0 to 30 min (ΔI (0-30) /ΔG(0-30) ), a measure of insulin secretion derived from the early period of the oral glucose tolerance test, predicts future diabetes. However, there are few data on secretory measures from the late oral glucose tolerance test period. We therefore investigated the association of the ratio of the area under the insulin curve to the area under the glucose curve from 60 to 120 min (I/G(AUC 60-120) ) with incident diabetes. METHODS: Participants were 1540 Mexican Americans and non-Hispanic whites in the San Antonio Heart Study who were free of diabetes at baseline. We analysed indices of sensitivity (Matsuda index) and secretion from the early (ΔI(0-30) /ΔG(0-30) ) and late oral glucose tolerance test periods (I/G(AUC 60-120) ). RESULTS: A total of 179 participants developed diabetes after 7.5 years. I/G(AUC 60-120) was an independent predictor of diabetes [odds ratio × 1 SD unit increase, 0.37 (0.26-0.54)] in a model that also included age, sex, ethnicity, body mass index, family history of diabetes, Matsuda index and (ΔI (0-30) /ΔG(0-30) ) as covariates. I/G(AUC 60-120) increased the C statistic (a test of discrimination) of the model (0.882 vs. 0.875, P=0.044). I/G(AUC 60-120) correctly reclassified one-fifth of individuals with moderate and strong risks of future diabetes. The net reclassification improvement was 0.13 (P<0.001) and the integrated discrimination improvement was 0.033 (P<0.001). CONCLUSIONS: An insulin secretory measure derived from the late oral glucose tolerance test period is useful for classifying individuals at risk of future diabetes independently of other risk factors, including insulin sensitivity and a secretory measure from the early oral glucose tolerance test period.
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Diabetes Mellitus Tipo 2/diagnóstico , Insulina/metabolismo , Adulto , Área Bajo la Curva , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/etnología , Diabetes Mellitus Tipo 2/metabolismo , Diagnóstico Precoz , Femenino , Prueba de Tolerancia a la Glucosa/métodos , Humanos , Incidencia , Resistencia a la Insulina/fisiología , Secreción de Insulina , Masculino , Americanos Mexicanos/etnología , Persona de Mediana Edad , Texas/epidemiología , Factores de TiempoRESUMEN
AIMS: We evaluated the relations between surrogate indices of insulin resistance and waist circumference, metabolic syndrome and coronary heart disease risk across Hispanic and non-Hispanic white populations. METHODS: The study was a cross-sectional analysis of participants without diabetes in the San Antonio Heart Study, Mexico City Diabetes Study and Spanish Insulin Resistance Study. We evaluated commonly used indices of insulin resistance, including homeostasis model assessment, McAuley's index, Gutt's insulin sensitivity index, Avignon's insulin sensitivity index and the Stumvoll index with and without demographics, the modified Matsuda index and the product of the triglycerides and glucose index. The metabolic syndrome was defined by American Heart Association/National Heart, Lung, and Blood Institute criteria and coronary heart disease risk by Framingham risk scores. RESULTS: The Stumvoll index with demographics and the Avignon's insulin sensitivity index had the strongest correlations with waist circumference across populations. The triglycerides and glucose and McAuley's indices had the most robust correlations with Framingham risk score. The triglycerides and glucose index had the greatest ability to detect individuals with the metabolic syndrome and ≥ 10% coronary heart disease risk. Some indices display significant variability in the strength of the relationship with adiposity and coronary heart disease risk across populations. CONCLUSIONS: There are significant differences between insulin resistance indices regarding the ability to detect the metabolic syndrome and coronary heart disease risk across populations. Studies may need to consider the index of insulin resistance that best suits the objectives.
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Glucemia/metabolismo , Enfermedades Cardiovasculares/sangre , Hispánicos o Latinos/estadística & datos numéricos , Resistencia a la Insulina , Síndrome Metabólico/sangre , Triglicéridos/sangre , Circunferencia de la Cintura , Población Blanca/estadística & datos numéricos , Adulto , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/fisiopatología , Estudios Transversales , Ayuno/sangre , Femenino , Humanos , Masculino , Síndrome Metabólico/epidemiología , Síndrome Metabólico/fisiopatología , México/epidemiología , Persona de Mediana Edad , Factores de Riesgo , Sensibilidad y EspecificidadRESUMEN
AIM: This study evaluated whether the risk of acute renal failure (ARF) increases with exenatide and sitagliptin use. METHODS: A retrospective cohort study of a large medical and pharmacy claims database was performed. Data for 4 91 539 patients were analysed. Cox proportional hazard models were used to compare the risk of ARF between diabetic and non-diabetic subjects and between diabetic patients treated with exenatide, sitagliptin and control medications. RESULTS: Adjusted Cox analyses showed diabetic subjects had a higher risk of ARF [HR 1.51, confidence interval (CI) 1.26-1.81, p < 0.001] than non-diabetic controls. Compared with diabetic controls, neither exenatide (HR 0.77, CI 0.42-1.41, p = 0.40) nor sitagliptin (HR 1.17, CI 0.82-1.65, p = 0.39) increased the risk of ARF. CONCLUSION: Our study revealed an increased incidence of ARF in diabetic versus non-diabetic patients but no association between use of exenatide or sitagliptin and ARF. Because of the limitations of this observational analysis, we cannot exclude the possibility of a very small increased risk.
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Lesión Renal Aguda/inducido químicamente , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Inhibidores de la Dipeptidil-Peptidasa IV/farmacología , Péptidos/farmacología , Pirazinas/farmacología , Triazoles/farmacología , Ponzoñas/farmacología , Lesión Renal Aguda/etiología , Lesión Renal Aguda/fisiopatología , Adolescente , Adulto , Estudios de Cohortes , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/fisiopatología , Inhibidores de la Dipeptidil-Peptidasa IV/administración & dosificación , Inhibidores de la Dipeptidil-Peptidasa IV/efectos adversos , Etiquetado de Medicamentos , Exenatida , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Péptidos/administración & dosificación , Péptidos/efectos adversos , Modelos de Riesgos Proporcionales , Pirazinas/administración & dosificación , Pirazinas/efectos adversos , Estudios Retrospectivos , Medición de Riesgo , Fosfato de Sitagliptina , Triazoles/administración & dosificación , Triazoles/efectos adversos , Ponzoñas/administración & dosificación , Ponzoñas/efectos adversos , Adulto JovenRESUMEN
AIMS: Associations of proinsulin-to-insulin ratios with incident type 2 diabetes have been inconsistent. The use of C-peptide as the denominator in the ratio may allow for better prediction because C-peptide concentration is not affected by hepatic insulin clearance. The objective of this paper was to compare fasting intact and split proinsulin-to-insulin ratios (PI/I, SPI/I) with intact and split proinsulin-to-C-peptide ratios (PI/C-pep, SPI/C-pep) in the prediction of type 2 diabetes. METHODS: Prospective data on 818 multi-ethnic adults without diabetes at baseline from the Insulin Resistance Atherosclerosis Study (IRAS) were used. Insulin sensitivity (S(I)) and acute insulin response (AIR) were determined from frequently sampled intravenous glucose tolerance tests, and fasting intact and split proinsulin were measured using specific two-site monoclonal antibody-based immunoradiometric assays. Associations of proinsulin ratios with type 2 diabetes were determined using logistic regression and differences in prediction were assessed by comparing areas under the receiver operating characteristic curve (AROCs). RESULTS: In logistic regression analyses, PI/C-pep and SPI/C-pep were more strongly associated with incident type 2 diabetes (n = 128) than PI/I and SPI/I, and were significantly better predictors of diabetes in AROC analyses (PI/C-pep = 0.662 vs PI/I = 0.603, p = 0.02; SPI/C-pep = 0.690 vs SPI/I = 0.631, p = 0.01). Both PI/C-pep and SPI/C-pep were associated with type 2 diabetes after adjustment for age, sex, ethnicity, waist circumference, impaired glucose tolerance, lipids and S(I). Both PI/C-pep and SPI/C-pep were significantly associated with incident type 2 diabetes in models that included AIR. CONCLUSIONS: Proinsulin-to-C-peptide ratios were stronger predictors of diabetes in comparison with proinsulin-to-insulin ratios. These findings support the use of C-peptide as the denominator for proinsulin ratios, to more accurately reflect the degree of disproportional hyperproinsulinaemia.
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Aterosclerosis/sangre , Péptido C/sangre , Resistencia a la Insulina , Insulina/sangre , Estado Prediabético/sangre , Proinsulina/sangre , Ayuno , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Curva ROC , Circunferencia de la CinturaRESUMEN
AIMS/HYPOTHESIS: Although protective relationships between coffee consumption and type 2 diabetes mellitus have consistently been observed, few studies have examined the relationships between coffee consumption and underlying pathophysiological defects that characterise diabetes aetiology. The aim of this study was to explore the associations between caffeinated and decaffeinated coffee consumption and measures of insulin sensitivity and secretion. METHODS: The study population included 954 multi-ethnic non-diabetic adults from the Insulin Resistance Atherosclerosis Study (IRAS). Multiple regression analyses were performed to examine the cross-sectional relationships between caffeinated and decaffeinated coffee intake and insulin sensitivity and acute insulin response, measured by a frequently sampled intravenous glucose tolerance test, 2 h postload glucose measured by OGTT, fasting insulin, and proinsulin to C-peptide ratios. RESULTS: Caffeinated coffee intake was positively associated with insulin sensitivity (ß = 0.054; SE = 0.026; p = 0.04) and inversely related to 2 h postload glucose (ß = -0.37; SE = 0.10; p = 0.0003) in fully adjusted models. Caffeinated coffee intake was not associated with acute insulin response or proinsulin ratios. Decaffeinated coffee intake was inversely related to 2 h postload glucose (ß = -0.47; SE = 0.18; p = 0.0096) and positively related to acute insulin response (ß = 0.191; SE = 0.077; p = 0.0132). Decaffeinated coffee intake was inversely related to the ratios of both intact and split proinsulin to C-peptide (ß = -0.150; SE = 0.061; p = 0.0148; ß = -0.254; SE = 0.068; p = 0.0002, respectively). CONCLUSIONS/INTERPRETATION: In this cross-sectional study, caffeinated coffee was positively related to insulin sensitivity and decaffeinated coffee was favourably related to measures of beta cell function. These results provide pathophysiological insight as to how coffee could impact the risk of type 2 diabetes mellitus.
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Cafeína , Café , Células Secretoras de Insulina/metabolismo , Adulto , Anciano , Glucemia/fisiología , Estudios Transversales , Femenino , Humanos , Resistencia a la Insulina/fisiología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Análisis de Regresión , Encuestas y CuestionariosRESUMEN
OBJECTIVE: Previous studies have replicated the association of variants within FTO (fat mass- and obesity-associated) intron 1 with obesity and adiposity quantitative traits in populations of European ancestry. Non-European populations, however, have not been so intensively studied. The goal of this investigation was to examine the association of FTO single-nucleotide polymorphisms (SNPs), prominent in the literature in a multiethnic sample of non-Hispanic White American (n=458), Hispanic American (n=373) and African American (n=288) subjects from the Insulin Resistance Atherosclerosis Study (IRAS). This cohort provides the unique ability to evaluate how variation within FTO influences measures of adiposity and glucose homeostasis in three different ethnicities, which were ascertained and examined using a common protocol. DESIGN: A total of 26 FTO SNPs were genotyped, including those consistently associated in the literature (rs9939609, rs8050136, rs1121980, rs1421085, rs17817449 and rs3751812), and tested for association with adiposity and glucose homeostasis traits. RESULTS: For the adiposity phenotypes, these and other SNPs were associated with body mass index (BMI) in both non-Hispanic Whites (P-values ranging from 0.015 to 0.048) and Hispanic Americans (P-values ranging from 7.1 × 10(-6) to 0.027). In Hispanic Americans, four other SNPs (rs8047395, rs10852521, rs8057044 and rs8044769) still showed evidence of association after multiple comparisons adjustment (P-values ranging from 5.0 × 10(-5) to 5.2 × 10(-4)). The historically associated BMI SNPs were not associated in the African Americans, but rs1108102 was associated with BMI (P-value of 5.4 × 10(-4)) after accounting for multiple comparisons. For glucose homeostasis traits, associations were seen with acute insulin response in non-Hispanic Whites and African Americans. However, all associations with glucose homeostasis measures were no longer significant after adjusting for multiple comparisons. CONCLUSION: These results replicate the association of FTO intron 1 variants with BMI in non-Hispanic Whites and Hispanic Americans but show little evidence of association in African Americans, suggesting that the effect of FTO variants on adiposity phenotypes shows genetic heterogeneity dependent on ethnicity.
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Adiposidad/genética , Aterosclerosis/genética , Glucemia/metabolismo , Resistencia a la Insulina/genética , Obesidad/genética , Adiposidad/etnología , Adulto , Negro o Afroamericano/genética , Anciano , Aterosclerosis/etnología , Índice de Masa Corporal , Femenino , Predisposición Genética a la Enfermedad , Genotipo , Hispánicos o Latinos/etnología , Hispánicos o Latinos/genética , Homeostasis , Humanos , Resistencia a la Insulina/etnología , Masculino , Persona de Mediana Edad , Obesidad/sangre , Obesidad/etnología , Polimorfismo de Nucleótido Simple , Población Blanca/genéticaRESUMEN
Membrane interactions and photooxidative membrane destabilization of titanium dioxide (TiO2) nanoparticles were investigated, focusing on the effects of membrane composition, notably phospholipid headgroup charge and presence of cholesterol. For this, we employed a battery of state-of-the-art methods for studies of bilayers formed by zwitterionic palmitoyloleoylphosphatidylcholine (POPC) containing also polyunsaturated palmitoylarachidonoylphosphocholine (PAPC), as well as its mixtures with anionic palmitoyloleoylphosphatidylglycerol (POPG) and cholesterol. It was found that the TiO2 nanoparticles display close to zero charge at pH 7.4, resulting in aggregation. At pH 3.4, in contrast, the 6 nm TiO2 nanoparticles are well dispersed due to a strongly positive ζ-potential. Mirroring this pH dependence, TiO2 nanoparticles were observed to bind to negatively charged lipid bilayers at pH 3.4, but much less so at pH 7.4. While nanoparticle binding has some destabilizing effect alone, illumination with ultraviolet (UV) light accentuates membrane destabilization, a result of oxidative stress caused by generated reactive oxygen species (ROS). Neutron reflectivity (NR), quartz crystal microbalance (QCM), and small-angle X-ray scattering (SAXS) results all demonstrate that membrane composition strongly influences membrane interactions and photooxidative destabilization of lipid bilayers. In particular, the presence of anionic POPG makes the bilayers more sensitive to oxidative destabilization, whereas a stabilizing effect was observed in the presence of cholesterol. Also, structural aspects of peroxidation were found to depend strongly on membrane composition, notably the presence of anionic phospholipids. The results show that membrane interactions and UV-induced ROS generation act in concert and need to be considered together to understand effects of lipid membrane composition on UV-triggered oxidative destabilization by TiO2 nanoparticles, e.g., in the context of oxidative damage of bacteria and cells.