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The prevalence of obesity and its associated pathologies continue to increase, which has led to a renewed interest in our major weight-regulating organ, the white adipose tissue. It has become clear that its development, expansion, and physiological function depend on proper crosstalk between each of its cellular constituents, with a central role for the vascular endothelium lining the blood vessels. Although first considered a mere barrier, the endothelium has emerged as a dynamic unit modulating many critical adipose tissue functions. It not only oversees the uptake of all nutrients to be stored in the adipocytes but also provides an important growth niche for adipocyte progenitors and regulates the expandability of the tissue during overfeeding and obesity. In this review, we describe the reciprocal relationship between endothelial cells, adipocytes, and obesity. We present recent studies that support an important role for endothelial cells as central mediators of many of the physiological and pathological functions of the adipose tissue and highlight several unknown aspects of adipose tissue vascular biology. This new perspective could present exciting opportunities to develop new therapeutic approaches against obesity-related pathologies and is thus of great interest in our increasingly obese society.
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Tejido Adiposo , Células Endoteliales , Adipocitos/fisiología , Tejido Adiposo/patología , Tejido Adiposo Blanco/patología , Células Endoteliales/patología , Humanos , ObesidadRESUMEN
KEY POINTS: Adipocyte enlargement is a key feature of obesity and associated with insulin resistance and metabolic disease The cause and consequences of adipocyte enlargement have remained hard to study in vitro due to a lack of human cell models with representative morphology This paper provides an easily set up spheroid culture method, HUVAS (human unilocular vascularized adipocyte spheroids), for the differentiation and culturing of human adipocytes with a more unilocular morphology We show that providing adipocyte progenitors with a vascular differentiation niche is key for achieving in vitro differentiated adipocytes with large lipid droplets Lipid treatment of the HUVAS spheroids can further adipocyte enlargement and induce cellular dysfunction, mimicking the in vivo effects of weight gain The model will allow a wider research community to perform mechanistic studies of the factors impacting on human adipocyte differentiation and growth, increasing our understanding of how obesity develops and why it has such detrimental consequences on whole body metabolism ABSTRACT: The rise in obesity prevalence has created an urgent need for new and improved methods to study human adipocytes and the pathogenic effects of weight gain in vitro. Despite the proven advantage of culturing adipocyte progenitors as 3D structures, the majority of studies continue to use traditional 2D cultures which result in small, multilocular adipocytes with poor representability. We hypothesized that providing differentiating pre-adipocytes with a vascular growth niche would mimic in vivo adipogenesis and improve the differentiation into unilocular adipocytes. Here we present HUVAS (human unilocular vascularized adipocyte spheroids), a simple, easily applicable culture protocol that allows for the differentiation of human adipocytes with a more unilocular morphology and larger lipid droplets than previous protocols. Moreover, we offer a protocol for inducing adipocyte enlargement in vitro, resulting in larger lipid droplets and development of several key features of adipocyte dysfunction, including altered adipokine secretion, impaired lipolysis and insulin resistance. Taken together, our HUVAS model offers an improved culture system for studying the cellular and molecular mechanisms causing metabolic dysfunction and inflammation in human adipose tissue during weight gain.
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Adipocitos , Tejido Adiposo , Adipocitos/metabolismo , Adipogénesis , Tejido Adiposo/metabolismo , Diferenciación Celular , Humanos , Aumento de PesoRESUMEN
Patatin-like phospholipase domain-containing proteins (PNPLAs) are involved in triglyceride hydrolysis and lipid-droplet homeostasis in mice, but the physiological significance of the PNPLAs for triglyceride metabolism in human hepatocytes is unclear. Here, we investigate the roles of PNPLA2, PNPLA3, and PNPLA4 in triglyceride metabolism of human Huh7 and HepG2 hepatoma cells using gene-specific inhibition methods. siRNA inhibition of PNPLA3 or PNPLA4 is not associated with changes in triglyceride hydrolysis, secretion of triglyceride-rich lipoproteins (TRLs), or triglyceride accumulation. However, PNPLA2 siRNA inhibition, both in the absence and presence of oleate-containing medium, or treatment with the PNPLA2 inhibitor Atglistatin reduced intracellular triglyceride hydrolysis and decreased TRL secretion. In contrast, PNPLA2 inhibition showed no effects on lipid-droplet homeostasis, which is the primary physiological function of PNPLA2 in nonhepatic tissues. Moreover, confocal microscopy analysis found no clear evidence for the localization of PNPLA2 around lipid droplets. However, significant colocalization of PNPLA2 with the endoplasmic reticulum marker protein disulfide-isomerase was found in HepG2 and Huh7 cells with Rcoloc values of 0.61 ± 0.06 and 0.81 ± 0.05, respectively. In conclusion, PNPLA2 influences TRL secretion, but is not involved in lipid-droplet homeostasis in human hepatoma cells, a physiological role that is quite distinct from the metabolic function of PNPLA2 in nonhepatic tissues.
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Lipasa/metabolismo , Metabolismo de los Lípidos/fisiología , Hígado/metabolismo , Western Blotting , Línea Celular Tumoral , Diglicéridos/metabolismo , Retículo Endoplásmico/metabolismo , Ácidos Grasos/metabolismo , Células Hep G2 , Humanos , Lipasa/genética , Metabolismo de los Lípidos/genética , Lipólisis/fisiología , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Microscopía Confocal , Enfermedad del Hígado Graso no Alcohólico/enzimología , Enfermedad del Hígado Graso no Alcohólico/genética , Enfermedad del Hígado Graso no Alcohólico/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Triglicéridos/metabolismoRESUMEN
INTRODUCTION: Loss of renal function is associated with high mortality from cardiovascular disease (CVD). Patients with chronic kidney disease (CKD) have altered circulating adipokine and nonesterified fatty acid concentrations and insulin resistance, which are features of disturbed adipose tissue metabolism. Because dysfunctional adipose tissue contributes to the development of CVD, we hypothesize that adipose tissue dysfunctionality in patients with CKD could explain, at least in part, their high rates of CVD. Therefore we characterized adipose tissue from patients with CKD, in comparison to healthy controls, to search for signs of dysfunctionality. METHODS: Biopsy samples of subcutaneous adipose tissue from 16 CKD patients and 11 healthy controls were analyzed for inflammation, fibrosis, and adipocyte size. Protein composition was assessed using 2-dimensional gel proteomics combined with multivariate analysis. RESULTS: Adipose tissue of CKD patients contained significantly more CD68-positive cells, but collagen content did not differ. Adipocyte size was significantly smaller in CKD patients. Proteomic analysis of adipose tissue revealed significant differences in the expression of certain proteins between the groups. Proteins whose expression differed the most were α-1-microglobulin/bikunin precursor (AMBP, higher in CKD) and vimentin (lower in CKD). Vimentin is a lipid droplet-associated protein, and changes in its expression may impair fatty acid storage/mobilization in adipose tissue, whereas high levels of AMBP may reflect oxidative stress. DISCUSSION: These findings demonstrate that adipose tissue of CKD patients shows signs of inflammation and disturbed functionality, thus potentially contributing to the unfavorable metabolic profile and increased risk of CVD in these patients.
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OBJECTIVE: Lipids are central to the development of atherosclerotic plaques. Specifically, which lipids are culprits remains controversial, and promising targets have failed in clinical studies. Sphingolipids are bioactive lipids present in atherosclerotic plaques, and they have been suggested to have both proatherogenic and antiatherogenic. However, the biological effects of these lipids remain unknown in the human atherosclerotic plaque. The aim of this study was to assess plaque levels of sphingolipids and investigate their potential association with and contribution to plaque vulnerability. APPROACH AND RESULTS: Glucosylceramide, lactosylceramide, ceramide, dihydroceramide, sphingomyelin, and sphingosine-1-phosphate were analyzed in homogenates from 200 human carotid plaques using mass spectrometry. Inflammatory activity was determined by analyzing plaque levels of cytokines and plaque histology. Caspase-3 was analyzed by ELISA technique. Expression of regulatory enzymes was analyzed with RNA sequencing. Human coronary artery smooth muscle cells were used to analyze the potential role of the 6 sphingolipids as inducers of plaque inflammation and cellular apoptosis in vitro. All sphingolipids were increased in plaques associated with symptoms and correlated with inflammatory cytokines. All sphingolipids, except sphingosine-1-phosphate, also correlated with histological markers of plaque instability. Lactosylceramide, ceramide, sphingomyelin, and sphingosine-1-phosphate correlated with caspase-3 activity. In vitro experiments revealed that glucosylceramide, lactosylceramide, and ceramide induced cellular apoptosis. All analyzed sphingolipids induced an inflammatory response in human coronary artery smooth muscle cells. CONCLUSIONS: This study shows for the first time that sphingolipids and particularly glucosylceramide are associated with and are possible inducers of plaque inflammation and instability, pointing to sphingolipid metabolic pathways as possible novel therapeutic targets.
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Enfermedades de las Arterias Carótidas/metabolismo , Inflamación/metabolismo , Músculo Liso Vascular/metabolismo , Miocitos del Músculo Liso/metabolismo , Placa Aterosclerótica , Esfingolípidos/metabolismo , Anciano , Apoptosis , Arterias Carótidas/metabolismo , Arterias Carótidas/patología , Enfermedades de las Arterias Carótidas/genética , Enfermedades de las Arterias Carótidas/patología , Caspasa 3/metabolismo , Línea Celular , Vasos Coronarios/metabolismo , Vasos Coronarios/patología , Citocinas/metabolismo , Femenino , Regulación Enzimológica de la Expresión Génica , Humanos , Inflamación/genética , Inflamación/patología , Masculino , Persona de Mediana Edad , Monocitos/metabolismo , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/patología , Miocitos del Músculo Liso/efectos de los fármacos , Miocitos del Músculo Liso/patología , Rotura Espontánea , Esfingolípidos/farmacologíaRESUMEN
Psoriasis is an immune-mediated inflammatory disease, which is associated with a high risk of developing systemic comorbidities, such as obesity, cardiovascular disease, and diabetes mellitus. However, the mechanistic links between psoriatic skin inflammation and systemic comorbidities remain largely unknown. MicroRNAs (miRNAs) are recently discovered gene regulators that play important roles in psoriasis skin inflammation. In this study we aimed to explore whether the skin inflammation in psoriasis affects miRNA expression of the underlying subcutaneous adipose tissue and whether this may be a link between psoriasis and comorbidities. To this end, we compared the miRNA expression profile of subcutaneous adipose tissue underneath lesional and nonlesional psoriatic skin. We further validated the differential expression of several miRNAs and characterized their expression patterns in different cell types present in subcutaneous adipose tissue. We focused on miR-26b-5p, which was highly up-regulated in subcutaneous adipose tissue underneath lesional psoriasis skin. We showed that it targets and down-regulates neutral cholesterol ester hydrolase 1, an enzyme essential for cholesterol efflux, in monocytes/macrophages, adipocytes, vascular endothelial cells, and fibroblasts. We conclude that this miRNA may serve as a mechanistic link between psoriatic skin inflammation and its systemic comorbidities.
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Hidrolasas de Éster Carboxílico/genética , Perfilación de la Expresión Génica , MicroARNs/genética , Psoriasis/genética , Grasa Subcutánea/metabolismo , Adulto , Anciano , Análisis de Varianza , Comorbilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Obesidad/diagnóstico , Obesidad/epidemiología , Psoriasis/epidemiología , Psoriasis/inmunología , Psoriasis/fisiopatología , Muestreo , Esterol Esterasa , Grasa Subcutánea/inmunología , Regulación hacia ArribaRESUMEN
PPARδ is involved in the inflammatory response and its expression is induced by cytokines, however, limited knowledge has been produced regarding its regulation. Since recent findings have shown that microRNAs, which are small non-coding RNAs that regulate gene expression, are involved in the immune response, we set out to investigate whether PPARδ can be regulated by microRNAs expressed in monocytes. Bioinformatic analysis identified a putative miR-9 target site within the 3'-UTR of PPARδ that was subsequently verified to be functional using reporter constructs. Primary human monocytes stimulated with LPS showed a downregulation of PPARδ and its target genes after 4 h while the expression of miR-9 was induced. Analysis of pro-inflammatory (M1) and anti-inflammatory (M2) macrophages showed that human PPARδ mRNA as well as miR-9 expression was higher in M1 compared to M2 macrophages. Furthermore, treatment with the PPARδ agonist, GW501516, induced the expression of PPARδ target genes in the pro-inflammatory M1 macrophages while no change was observed in the anti-inflammatory M2 macrophages. Taken together, these data suggest that PPARδ is regulated by miR-9 in monocytes and that activation of PPARδ may be of importance in M1 pro-inflammatory but not in M2 anti-inflammatory macrophages in humans.
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Regulación de la Expresión Génica , Inflamación/genética , Inflamación/patología , MicroARNs/metabolismo , Monocitos/metabolismo , PPAR delta/genética , Secuencia de Bases , Células Cultivadas , Regulación de la Expresión Génica/efectos de los fármacos , Células HEK293 , Humanos , Lipopolisacáridos/farmacología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , MicroARNs/genética , Datos de Secuencia Molecular , Monocitos/efectos de los fármacos , Monocitos/patología , PPAR delta/agonistas , PPAR delta/metabolismo , Perilipina-2 , ARN Mensajero/genética , ARN Mensajero/metabolismo , Tiazoles/farmacología , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/genéticaRESUMEN
BACKGROUND: Inflammation and increased ceramide concentrations characterise adipose tissue of obese women with high liver fat content compared to equally obese women with normal liver fat content. The present study characterises enzymes involved in ceramide metabolism in subcutaneous and intra-abdominal adipose tissue. METHODS: Pathways leading to increased ceramide concentrations in inflamed versus non-inflamed adipose tissue were investigated by quantifying expression levels of key enzymes involved in ceramide metabolism. Sphingomyelinases (sphingomyelin phosphodiesterases SMPD1-3) were investigated further using immunohistochemistry to establish their location within adipose tissue, and their mRNA expression levels were determined in subcutaneous and intra-abdominal adipose tissue from both non-obese and obese subject. RESULTS: Gene expression levels of sphingomyelinases, enzymes that hydrolyse sphingomyelin to ceramide, rather than enzymes involved in de novo ceramide synthesis, were higher in inflamed compared to non-inflamed adipose tissue of obese women (with high and normal liver fat contents respectively). Sphingomyelinases were localised to both macrophages and adipocytes, but also to blood vessels and to extracellular regions surrounding vessels within adipose tissue. Expression levels of SMPD3 mRNA correlated significantly with concentrations of different ceramides and sphingomyelins. In both non-obese and obese subjects SMPD3 mRNA levels were higher in the more inflamed intra-abdominal compared to the subcutaneous adipose tissue depot. CONCLUSIONS: Generation of ceramides within adipose tissue as a result of sphingomyelinase action may contribute to inflammation in human adipose tissue.
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Ceramidas/metabolismo , Grasa Intraabdominal/enzimología , Obesidad/enzimología , Esfingomielina Fosfodiesterasa/metabolismo , Grasa Subcutánea/enzimología , Adipocitos/enzimología , Adulto , Apolipoproteínas B/metabolismo , Ceramidasas/genética , Ceramidasas/metabolismo , Femenino , Humanos , Grasa Intraabdominal/irrigación sanguínea , Grasa Intraabdominal/patología , Metabolismo de los Lípidos , Hígado/patología , Macrófagos/enzimología , Persona de Mediana Edad , Obesidad/patología , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Esfingomielina Fosfodiesterasa/genética , Esfingosina N-Aciltransferasa/genética , Esfingosina N-Aciltransferasa/metabolismo , Grasa Subcutánea/irrigación sanguínea , Grasa Subcutánea/patologíaRESUMEN
BACKGROUND: A sedentary lifestyle predisposes to cardiometabolic diseases. Lifestyle changes such as increased physical activity improve a range of cardiometabolic risk factors. The objective of this study was to examine whether functional changes in adipose tissue were related to these improvements. METHODS: Seventy-three sedentary, overweight (mean BMI 29.9 ± 3.2 kg/m2) and abdominally obese, but otherwise healthy men and women (67.6 ± 0.5 years) from a randomised controlled trial of physical activity on prescription over a 6-month period were included (control n = 43, intervention n = 30). Detailed examinations were carried out at baseline and at follow-up, including fasting blood samples, a comprehensive questionnaire and subcutaneous adipose tissue biopsies for fatty acid composition analysis (n = 73) and quantification of mRNA expression levels of 13 candidate genes (n = 51), including adiponectin, leptin and inflammatory cytokines. RESULTS: At follow-up, the intervention group had a greater increase in exercise time (+137 min/week) and a greater decrease in body fat mass (-1.5 kg) compared to the control subjects (changes of 0 min/week and -0.5 kg respectively). Circulating concentrations of adiponectin were unchanged, but those of leptin decreased significantly more in the intervention group (-1.8 vs -1.1 ng/mL for intervention vs control, P < 0.05). The w6-polyunsaturated fatty acid content, in particular linoleic acid (18:2w6), of adipose tissue increased significantly more in the intervention group, but the magnitude of the change was small (+0.17 vs +0.02 percentage points for intervention vs control, P < 0.05). Surprisingly leptin mRNA levels in adipose tissue increased in the intervention group (+107% intervention vs -20% control, P < 0.05), but changes in expression of the remaining genes did not differ between the groups. CONCLUSIONS: After a 6-month period of increased physical activity in overweight elderly individuals, circulating leptin concentrations decreased despite increased levels of leptin mRNA in adipose tissue. Otherwise, only minor changes occurred in adipose tissue, although several improvements in metabolic parameters accompanied the modest increase in physical activity.
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Ejercicio Físico , Obesidad Abdominal/metabolismo , Grasa Subcutánea/metabolismo , Adiponectina/sangre , Anciano , Ácidos Grasos/metabolismo , Femenino , Expresión Génica , Humanos , Leptina/sangre , Modelos Lineales , Masculino , Obesidad Abdominal/sangre , Estadísticas no Paramétricas , Grasa Subcutánea/patología , Transcriptoma , Resultado del Tratamiento , Pérdida de PesoRESUMEN
Although saturated and monounsaturated very-long-chain fatty acids (VLCFAs) have long been associated with undesirable effects on health, including obesity, heart failure, and atherosclerosis, the physiological role of endogenous synthesis is largely unknown. The fatty acid elongase ELOVL3 is involved in the synthesis of C20-C24 saturated and monounsaturated VLCFAs mainly in liver, brown and white adipose tissue, and triglyceride-rich glands such as the sebaceous and meibomian glands. Here we show that ablation of ELOVL3 leads to reduced adiponectin levels, constrained expansion of adipose tissue, and resistance against diet-induced obesity, a situation that is more exaggerated in female mice. Both female and male knockout mice show reduced hepatic lipogenic gene expression and triglyceride content, a situation that is associated with reduced de novo fatty acid synthesis and uptake. As a consequence, the VLDL-triglyceride level in serum is significantly reduced. Remarkably, despite increased energy expenditure, markedly reduced serum levels of leptin, and increased expression of orexigenic peptides in the hypothalamus, the Elovl3(-/-) mice do not compensate by increased food intake. Thus, these results reveal that C20-C22 saturated and monounsaturated VLCFAs produced by ELOVL3 are indispensable for appropriate synthesis of liver triglycerides, fatty acid uptake, and storage in adipose tissue.
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Acetiltransferasas/genética , Acetiltransferasas/metabolismo , Dieta , Obesidad/enzimología , Adipoquinas/metabolismo , Adiponectina/sangre , Tejido Adiposo/metabolismo , Animales , Metabolismo Basal/genética , Células Cultivadas , Ingestión de Alimentos/genética , Elongasas de Ácidos Grasos , Femenino , Regulación Enzimológica de la Expresión Génica , Lipogénesis/genética , Lipoproteínas VLDL/biosíntesis , Lipoproteínas VLDL/sangre , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/metabolismo , Factores Sexuales , Triglicéridos/biosíntesis , Triglicéridos/sangreRESUMEN
BACKGROUND: Insufficient physical activity (PA), overweight and abdominal obesity are increasing global public health problems. DESIGN: Randomized controlled 6-month intervention study. METHODS: One hundred and one 68-year-old individuals (57% female) with low PA, overweight (BMI 25-40 kg/m) and abdominal obesity (waist circumference >88 cm in women and >102 cm in men), were randomized to PA on prescription (PAP) or a minimal intervention. PA measured by several methods, anthropometric parameters, body composition and cardiometabolic risk factors were measured at baseline and after intervention. RESULTS: Favourable changes in anthropometrics, body composition, S-glucose, glycosolated haemoglobin (HbA1c), blood lipids and apolipoproteins were seen in the PAP group. In the control group, however, some positive changes were also noted. Bodyweight, neck circumference, fat mass, S-cholesterol and HbA1c decreased significantly more in the PAP group. CONCLUSION: Individualized PAP improves body composition and cardiometabolic risk factors in sedentary older overweight individuals. PAP might be useful in clinical practice to counteract the epidemic of sedentary lifestyle and concomitant cardiometabolic disorders.
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Composición Corporal , Actividad Motora , Sobrepeso/fisiopatología , Anciano , Apolipoproteínas/sangre , Glucemia/análisis , Presión Sanguínea , Índice de Masa Corporal , Peso Corporal , Colesterol/sangre , Femenino , Hemoglobina Glucada/análisis , Humanos , Masculino , Cuello/anatomía & histología , Sobrepeso/sangre , Factores de Riesgo , Triglicéridos/sangre , Circunferencia de la CinturaRESUMEN
AIMS: We investigated whether polymorphisms in candidate genes involved in lipid metabolism and type 2 diabetes are related to liver fat content. METHODS: Liver fat content was measured using proton magnetic resonance spectroscopy ((1)H-MRS) in 302 Finns, in whom single nucleotide polymorphisms (SNPs) in acyl-CoA synthetase long-chain family member 4 (ACSL4), adiponectin receptors 1 and 2 (ADIPOR1 and ADIPOR2), and the three peroxisome proliferator-activated receptors (PPARA, PPARD, and PPARG) were analyzed. To validate our findings, SNPs significantly associated with liver fat content were studied in two independent cohorts and related to surrogate markers of liver fat content. RESULTS: In the Finnish subjects, polymorphisms in ACSL4 (rs7887981), ADIPOR2 (rs767870), and PPARG (rs3856806) were significantly associated with liver fat content measured with (1)H-MRS after adjusting for age, gender, and BMI. Anthropometric and circulating parameters were comparable between genotypes. In the first validation cohort of approximately 600 Swedish men, ACSL4 rs7887981 was related to fasting insulin and triglyceride concentrations, and ADIPOR2 rs767870 to serum gamma glutamyltransferase concentrations after adjusting for BMI. The SNP in PPARG (rs3856806) was not significantly associated with any relevant metabolic parameter in this cohort. In the second validation cohort of approximately 3000 subjects from Western Finland, ADIPOR2 rs767870, but not ACSL4 rs7887981 was related to fasting triglyceride concentrations. CONCLUSIONS: Genetic variation, particularly in the ADIPOR2 gene, contributes to variation in hepatic fat accumulation in humans.
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Metabolismo de los Lípidos/genética , Hígado/metabolismo , Receptores de Adiponectina/genética , Adolescente , Adulto , Anciano , Análisis de Varianza , Estudios de Cohortes , Hígado Graso/epidemiología , Hígado Graso/genética , Hígado Graso/metabolismo , Femenino , Finlandia/epidemiología , Frecuencia de los Genes , Marcadores Genéticos , Variación Genética , Humanos , Espectroscopía de Resonancia Magnética , Masculino , Persona de Mediana Edad , Polimorfismo Genético/genética , Polimorfismo de Nucleótido Simple , Suecia/epidemiología , Triglicéridos/metabolismo , Adulto JovenRESUMEN
AIMS: Prospective studies indicate that apolipoprotein measurements predict coronary heart disease (CHD) risk; however, evidence is conflicting, especially in the US. Our aim was to assess whether measurements of apolipoprotein B (apoB) and apolipoprotein A-I (apoA-I) can improve the ability to predict CHD death beyond what is possible based on traditional cardiovascular (CV) risk factors and clinical routine lipid measurements. METHODS AND RESULTS: We analysed prospectively associations of apolipoprotein measurements, traditional CV risk factors, and clinical routine lipid measurements with CHD mortality in a multi-ethnic representative subset of 7594 US adults (mean age 45 years; 3881 men and 3713 women, median follow-up 124 person-months) from the Third National Health and Nutrition Examination Survey mortality study. Multiple Cox-proportional hazards regression was applied. There were 673 CV deaths of which 432 were from CHD. Concentrations of apoB [hazard ratio (HR) 1.98, 95% confidence interval (CI) 1.09-3.61], apoA-I (HR 0.48, 95% CI 0.27-0.85) and total cholesterol (TC) (HR 1.17, 95% CI 1.02-1.34) were significantly related to CHD death, whereas high density lipoprotein cholesterol (HDL-C) (HR 0.68, 95% CI 0.45-1.05) was borderline significant. Both the apoB/apoA-I ratio (HR 2.14, 95% CI 1.11-4.10) and the TC/HDL-C ratio (HR 1.10, 95% CI 1.04-1.16) were related to CHD death. Only apoB (HR 2.01, 95% CI 1.05-3.86) and the apoB/apoA-I ratio (HR 2.09, 95% CI 1.04-4.19) remained significantly associated with CHD death after adjusting for CV risk factors. CONCLUSION: In the US population, apolipoprotein measurements significantly predict CHD death, independently of conventional lipids and other CV risk factors (smoking, dyslipidaemia, hypertension, obesity, diabetes and C-reactive protein). Furthermore, the predictive ability of apoB alone to detect CHD death was better than any of the routine clinical lipid measurements. Inclusion of apolipoprotein measurements in future clinical guidelines should not be discarded.
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Apolipoproteína A-I/sangre , Apolipoproteínas B/sangre , Enfermedad Coronaria/sangre , Enfermedad Coronaria/mortalidad , Factores de Edad , Análisis de Varianza , Biomarcadores/sangre , Pesos y Medidas Corporales , Estudios de Cohortes , Enfermedad Coronaria/diagnóstico , Femenino , Humanos , Lípidos/sangre , Masculino , Persona de Mediana Edad , Oportunidad Relativa , Valor Predictivo de las Pruebas , Estudios Prospectivos , Estados Unidos/epidemiologíaRESUMEN
Recent reports suggest that IGF (insulin-like growth factor)-I and IGFBP-3 (IGF-binding protein-3) have independent and opposing mechanistic effects on insulin. The aim of the present study was to assess the relationship between the IGF-I/IGFBP-3 ratio and the metabolic syndrome. We examined 3281 subjects (1463 men and 1818 women, aged 20-49 years), otherwise healthy adults, who participated in NHANES III (Third National Health and Nutrition Examination Survey), which has released measurements of IGF-I and IGFBP-3. Insulin resistance was estimated using the computer HOMA2 (homoeostatic model assessment 2) model. The updated ATP-III (Adult Treatment Panel III) definition of the metabolic syndrome was used. We applied adjusted logistic and linear regression models. After adjusting for age and race, men and women in the lowest quartile of the IGF-I/IGFBP-3 ratio were 3-fold more likely to meet the ATP-III definition of the metabolic syndrome and twice as likely to be insulin-resistant. Mean values of the IGF-I/IGFBP-3 ratio decreased significantly as the number of metabolic syndrome components increased (P<0.0001, as determined by ANOVA). The area under the ROC (receiver operating characteristic) curve for detecting insulin resistance using the IGF-I/IGFBP-3 ratio was 0.760, significantly improving upon either protein alone (P=0.01). In conclusion, the IGF-I/IGFBP-3 ratio is significantly associated with the metabolic syndrome. Calculating the ratio of these two proteins may provide insight into the metabolic syndrome clustering phenomenon.
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Proteínas de Unión a Factor de Crecimiento Similar a la Insulina/sangre , Factor I del Crecimiento Similar a la Insulina/análisis , Síndrome Metabólico/sangre , Adulto , Biomarcadores/sangre , Estudios Transversales , Femenino , Humanos , Resistencia a la Insulina/fisiología , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina , Masculino , Síndrome Metabólico/diagnóstico , Persona de Mediana Edad , Modelos Estadísticos , Adulto JovenRESUMEN
AIMS: We examined whether antibodies against peptides 45 and 210 of apoB-100 are related to myocardial infarction (MI) and severity of coronary atherosclerosis. METHODS AND RESULTS: Three hundred and eighty-seven survivors of a first MI (aged <60 years) and 387 sex- and age-matched controls were characterized in detail. IgG and IgM autoantibodies against native and malondialdehyde (MDA)-modified peptides 45 and 210 of apoB-100 (amino acids 661-680 and 3136-3155) were quantified in plasma and quantitative coronary angiography was performed in 243 patients. Post-infarction patients had significantly lower IgG against the native peptide 210 (IgG-p210(nat)) and higher IgM against the MDA-modified peptide 210 (IgM-p210(MDA)) compared with controls, whereas no differences were found for other antibodies. Plasma concentrations of IgG-p210(nat), but not IgM-p210(MDA), were independently and inversely related to the degree of coronary atherosclerosis in patients. In multiple logistic regression analysis (including established risk indicators), MI risk was 0.55 (95%CI: 0.37-0.81) for individuals in the IgG-p210(nat) upper quartile compared with the remaining individuals. CONCLUSION: Circulating IgG antibodies against the native peptide 210 of apoB-100 are inversely related to the severity of coronary atherosclerosis and associated with lower risk of MI. Epitope 210 of apoB-100 emerges as a target for immunization against atherosclerosis in humans.
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Apolipoproteína B-100/inmunología , Autoanticuerpos/sangre , Enfermedad de la Arteria Coronaria/inmunología , Infarto del Miocardio/inmunología , Péptidos/inmunología , Linfocitos T Reguladores/inmunología , Apolipoproteína B-100/sangre , Autoanticuerpos/inmunología , Angiografía Coronaria/métodos , Enfermedad de la Arteria Coronaria/tratamiento farmacológico , Femenino , Humanos , Inmunoglobulina G/metabolismo , Inmunoglobulina M/metabolismo , Masculino , Persona de Mediana Edad , Infarto del Miocardio/tratamiento farmacológico , Péptidos/sangre , Factores de RiesgoRESUMEN
BACKGROUND: Skipping meals is a common practice in our current society; however, it is not clear whether eating meals regularly is associated with the metabolic syndrome. OBJECTIVE: Our aim was to assess the association of eating meals regularly with parameters of the metabolic syndrome and insulin resistance in a representative population-based cohort of 60-year-old men and women. METHODS AND PROCEDURES: A population-based cross-sectional study of 3,607 individuals (1,686 men and 1,921 women), aged 60 years, was conducted in Stockholm County, Sweden. Medical history, socioeconomic factors, and lifestyle data were collected by a questionnaire and a medical examination, which included laboratory tests. RESULTS: Of the subjects who were regular eaters, 20% fulfilled the criteria for the metabolic syndrome vs. 27% of subjects who were irregular eaters (P < 0.0001). The adjusted odds ratio (OR) for having the greatest number of components of the metabolic syndrome in subjects who were regular eaters was 0.27 (95% confidence interval (CI), 0.13-0.54) using subjects who did not fulfill any criteria for the metabolic syndrome as a reference group. Eating meals regularly was also inversely related to insulin resistance (OR, 0.68 (95% CI, 0.48-0.97)) and to gamma-glutamyl transferase (OR, 0.52 (95% CI, 0.33-83)) after full adjustment. DISCUSSION: Eating meals regularly is inversely associated to the metabolic syndrome, insulin resistance and (high) serum concentrations of gamma-glutamyl transferase. These findings suggest that eating meals irregularly may be part of several potential environmental risk factors that are associated with the metabolic syndrome and may have future implications in giving dietary advice to prevent and/or treat the syndrome.
Asunto(s)
Ingestión de Alimentos/fisiología , Conducta Alimentaria/fisiología , Síndrome Metabólico/epidemiología , Síndrome Metabólico/fisiopatología , Estudios de Cohortes , Estudios Transversales , Recolección de Datos , Femenino , Humanos , Resistencia a la Insulina/fisiología , Modelos Logísticos , Masculino , Persona de Mediana Edad , Factores de Riesgo , gamma-Glutamiltransferasa/sangreRESUMEN
Despite the high prevalence of nonalcoholic fatty liver disease (NAFLD), little is known of its pathogenesis based on study of human liver samples. By the use of Affymetrix GeneChips (17,601 genes), we investigated gene expression in the human liver of subjects with extreme steatosis due to NAFLD without histological signs of inflammation (liver fat 66.0 +/- 6.8%) and in subjects with low liver fat content (6.4 +/- 2.7%). The data were analyzed by using sequence-based reannotation of Affymetrix probes and a robust model-based normalization method. We identified genes involved in hepatic glucose and lipid metabolism, insulin signaling, inflammation, coagulation, and cell adhesion to be significantly associated with liver fat content. In addition, genes involved in ceramide signaling (MAP2K4) and metabolism (UGCG) were found to be positively associated with liver fat content. Genes involved in lipid metabolism (PLIN, ACADM), fatty acid transport (FABP4, CD36), amino acid catabolism (BCAT1), and inflammation (CCL2) were validated by real-time PCR and were found to be upregulated in subjects with high liver fat content. The data show that multiple changes in gene expression characterize simple steatosis.
Asunto(s)
Hígado Graso/genética , Perfilación de la Expresión Génica , Acil-CoA Deshidrogenasa/genética , Adulto , Antígenos CD36/genética , Metabolismo de los Hidratos de Carbono/genética , Proteínas Portadoras , Quimiocina CCL2/genética , Regulación hacia Abajo/genética , Proteínas de la Matriz Extracelular/genética , Proteínas de Unión a Ácidos Grasos/genética , Femenino , Humanos , Inflamación/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Metabolismo de los Lípidos/genética , Persona de Mediana Edad , Análisis de Secuencia por Matrices de Oligonucleótidos , Perilipina-1 , Fosfoproteínas/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transaminasas/genética , Regulación hacia Arriba/genéticaRESUMEN
BACKGROUND: Insulin-induced genes (INSIGs) encode proteins that block proteolytic activation of sterol regulatory element-binding proteins, transcription factors that regulate lipogenic enzymes, and adipocyte differentiation. OBJECTIVE: Here, we analyzed the relative significance of INSIG1 and INSIG2 in human liver and adipocyte metabolism, and defined a novel, functional polymorphism in the promoter of INSIG2 associated with body mass index. RESEARCH METHODS: Variations in gene expression of different human tissues, of hepatoma cells exposed to INSIG1 and INSIG2 gene silencing probes, and of differentiating 3T3-L1 adipocytes were determined by real-time quantitative PCR. The functional significance of a novel polymorphism in the promoter of INSIG2 was analyzed using in vitro methods and gene expression analysis of human adipose tissue, whereas the phenotype associated with this polymorphism was studied in two cohorts of middle-aged men. RESULTS: Gene expression analysis of 17 human tissues demonstrated that INSIG1 is highly expressed in the liver, whereas INSIG2 is ubiquitously expressed. Gene silencing experiments confirmed that INSIG1, but not INSIG2, regulates the expression of sterol regulatory element-binding proteins target genes in human hepatoma cells. In contrast, adipocyte differentiation of 3T3-L1 cells was associated with a 13-fold increase in expression of INSIG2. Significant relationships between the INSIG2-102G/A polymorphism and body mass index were observed in two cohorts of middle-aged men (ANOVA P = 0.017 and 0.044, respectively). In vitro studies and analysis of allele-specific expression in human adipose tissue substantiated the functional significance of the INSIG2-102G/A polymorphism. CONCLUSION: INSIG2 is involved in adipocyte metabolism and body weight regulation.
Asunto(s)
Adipocitos/metabolismo , Peso Corporal , Péptidos y Proteínas de Señalización Intracelular/fisiología , Proteínas de la Membrana/fisiología , Adipogénesis , Índice de Masa Corporal , Línea Celular Tumoral , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Masculino , Proteínas de la Membrana/genética , Persona de Mediana Edad , Polimorfismo Genético , Regiones Promotoras Genéticas , ARN Mensajero/análisis , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/fisiologíaRESUMEN
CCL2 (MCP-1, monocyte chemoattractant protein 1) and CCL3 (MIP-1alpha, macrophage inflammatory protein 1alpha) are required for macrophage infiltration in adipose tissue. Insulin increases CCL2 expression in adipose tissue and in serum more in insulin-resistant obese than in insulin-sensitive lean mice, but whether this is true in humans is unknown. We compared basal expression and insulin regulation of CCL2 and CCL3 in adipose tissue and MCP-1 and MIP-1alpha in serum between insulin-resistant and insulin-sensitive human subjects. Subcutaneous adipose tissue biopsies and blood samples were obtained before and at the end of 6 h of in vivo euglycemic hyperinsulinemia (maintained by the insulin clamp technique) in 11 lean insulin-sensitive and 10 obese insulin-resistant women, and before and after a 6-h saline infusion in 8 women. Adipose tissue mRNA concentrations of monocyte/macrophage markers CD68, EMR1, ITGAM, ADAM8, chemokines CCL2 and CCL3, and housekeeping gene ribosomal protein large P0 (RPLP0) were measured by means of real-time PCR at baseline. In addition, mRNA concentrations of CCL2, CCL3, and RPLP0 were measured after insulin infusion. Levels of MCP-1 and MIP-1alpha were determined in serum, and protein concentration of MCP-1 was determined in adipose tissue at baseline and after insulin infusion. Basally, expression of the macrophage markers CD68 and EMR1 were increased in adipose tissue of insulin-resistant subjects. Insulin increased MCP-1 gene and protein expression significantly more in the insulin-resistant than in the insulin-sensitive subjects. Basally expression of CCL2 and CCL3 and expression of macrophage markers CD68 and ITGAM were significantly correlated. In serum, MCP-1 decreased significantly in insulin-sensitive but not insulin-resistant subjects. MIP-1alpha was undetectable in serum. Insulin regulation of CCL2 differs between insulin-sensitive and -resistant subjects in a direction that could exacerbate adipose tissue inflammation.
Asunto(s)
Tejido Adiposo/metabolismo , Quimiocina CCL2/biosíntesis , Insulina/fisiología , Obesidad/metabolismo , Adolescente , Adulto , Biomarcadores , Quimiocina CCL2/genética , Quimiocina CCL3/biosíntesis , Quimiocinas/biosíntesis , ADN Complementario/análisis , ADN Complementario/biosíntesis , Femenino , Técnica de Clampeo de la Glucosa , Humanos , Resistencia a la Insulina , Persona de Mediana Edad , Obesidad/genética , ARN/análisis , ARN/biosíntesisRESUMEN
The role of inflammation in atherosclerotic disease is well established, but the role of autoantibodies against modified apolipoprotein (apo) B-100 remains unclear. The metabolic syndrome is associated with a proinflammatory state, a predominance of small dense low-density lipoprotein (LDL) particles, and an increased risk for atherosclerotic diseases. Previous studies have shown specific autoantibodies against modified apo B-100 (within LDL) to be related to human atherosclerotic disease. The objective of the present study was to investigate whether autoantibodies against modified apo B-100 are related to parameters of the metabolic syndrome, such as small dense LDL. Two hundred ninety-one healthy men were investigated for different metabolic, anthropometric, and inflammatory variables; LDL peak particle size; and distribution of LDL in 4 subfractions. Subjects were grouped according to LDL peak size > or = 23.5 nm (pattern A, n = 230) or <23.5 nm (pattern B, n = 61). Immunoglobulin (Ig) G and IgM antibodies against 2 aldehyde-modified peptide sequences, denoted as 45 and 210, within apo B-100 were quantified. Levels of IgG(45), but not the other autoantibodies, were significantly higher in pattern B individuals (with a predominance of small dense LDL particles) compared with pattern A (P < .01). Relationships for both IgG(45) and IgG(210) with parameters typically associated with the metabolic syndrome were found. Only IgG(45) tended to be higher in individuals with the metabolic syndrome compared with those without (P = .07). We conclude that subjects with a predominance of small dense LDL particles have elevated concentrations of IgG(45) in the circulation, which reflect an activated immune response to a specific epitope of modified apo B-100.