Association between exposure to air pollution and blood lipids in the general population of Spain

BACKGROUND AND AIMS

We aimed to assess the associations of exposure to air pollutants and standard and advanced lipoprotein measures, in a nationwide sample representative of the adult population of Spain.

METHODS

We included 4647 adults (>18 years), participants in the national, cross-sectional, population-based di@bet.es study, conducted in 2008-2010. Standard lipid measurements were analysed on an Architect C8000 Analyzer (Abbott Laboratories SA). Lipoprotein analysis was made by an advanced 1 H-NMR lipoprotein test (Liposcale®). Participants were assigned air pollution concentrations for particulate matter <10 μm (PM10 ), <2.5 μm (PM2.5 ) and nitrogen dioxide (NO2 ), corresponding to the health examination year, obtained by modelling combined with measurements taken at air quality stations (CHIMERE chemistry-transport model).

RESULTS

In multivariate linear regression models, each IQR increase in PM10 , PM2.5 and NO2 was associated with 3.3%, 3.3% and 3% lower levels of HDL-c and 1.3%, 1.4% and 1.1% lower HDL particle (HDL-p) concentrations (p < .001 for all associations). In multivariate logistic regression, there was a significant association between PM10 , PM2.5 and NO2 concentrations and the odds of presenting low HDL-c (<40 mg/dL), low HDL-p (

CONCLUSIONS

Our study shows an association between the exposure to air pollutants and blood lipids in the general population of Spain, suggesting a link to atherosclerosis.

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Key Words

• HDL
• air pollution
• cholesterol
• lipids
• lipoprotein
• triglyceride

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MESH Headings

• Male
• Adult
• Humans
• Nitrogen Dioxide/analysis
• Spain/epidemiology
• Cross-Sectional Studies
• Air Pollution/adverse effects
• Air Pollution/analysis
• Air Pollutants/analysis
• Particulate Matter/analysis
• Lipids
• Lipoproteins/analysis
• Environmental Exposure/adverse effects

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Grants

• RC-0006-2016 Consejería de Salud y Bienestar Social, Junta de Andalucía
• CM21/00214 Instituto de Salud Carlos III
• INT21/00037 Instituto de Salud Carlos III
• PI17/02136 Instituto de Salud Carlos III
• PI20/01322 Instituto de Salud Carlos III

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Affiliation(s)

Sergio Valdés Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga/Universidad de Málaga, Instituto de Investigación Biomedica de Málaga-IBIMA, Málaga, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
Viyey Doulatram-Gamgaram Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga/Universidad de Málaga, Instituto de Investigación Biomedica de Málaga-IBIMA, Málaga, Spain
Cristina Maldonado-Araque Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga/Universidad de Málaga, Instituto de Investigación Biomedica de Málaga-IBIMA, Málaga, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
Eva García-Escobar Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga/Universidad de Málaga, Instituto de Investigación Biomedica de Málaga-IBIMA, Málaga, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
Sara García-Serrano Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga/Universidad de Málaga, Instituto de Investigación Biomedica de Málaga-IBIMA, Málaga, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
Wasima Oualla-Bachiri Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga/Universidad de Málaga, Instituto de Investigación Biomedica de Málaga-IBIMA, Málaga, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
Marta García-Vivanco Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) - División de Contaminación Atmosférica, Madrid, Spain
Juan Luis Garrido Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) - División de Contaminación Atmosférica, Madrid, Spain
Victoria Gil Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) - División de Contaminación Atmosférica, Madrid, Spain
Fernando Martín-Llorente Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) - División de Contaminación Atmosférica, Madrid, Spain
Alfonso Calle-Pascual Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain Department of Endocrinology and Nutrition and Instituto de Investigación Sanitaria University Hospital S. Carlos (IdISSC), Department Medicine II, Universidad Complutense (UCM), Madrid, Spain
Luis Castaño Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain Hospital Universitario Cruces, BioCruces, UPV/EHU, Barakaldo, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
Elías Delgado Department of Endocrinology and Nutrition, Hospital Universitario Central de Asturias/University of Oviedo, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
Edelmiro Menéndez Department of Endocrinology and Nutrition, Hospital Universitario Central de Asturias/University of Oviedo, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
Josep Franch-Nadal Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain EAP Raval Sud, Institut Català de la Salut, Red GEDAPS, Primary Care, Unitat de Suport a la Recerca (IDIAP - Fundació Jordi Gol), Barcelona, Spain
Sonia Gaztambide Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain Department of Endocrinology and Nutrition, Hospital Universitario Cruces - BioCruces Bizkaia - UPV-EHU, Baracaldo, Barcelona, Spain
Joan Girbés Diabetes Unit, Hospital Arnau de Vilanova, Valencia, Spain
F Javier Chaves Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain Genomic Studies and Genetic Diagnosis Unit, Fundación de Investigación del Hospital Clínico de Valencia - INCLIVA, Valencia, Spain
José L Galán-García Department of Applied Mathematics, University of Málaga, Málaga, Spain
Gabriel Aguilera-Venegas Department of Applied Mathematics, University of Málaga, Málaga, Spain
Joan Carles Vallvé Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain Research Unit on Lipids and Atherosclerosis, Sant Joan University Hospital, Rovira i Virgili University, IISPV, Reus, Spain
Núria Amigó Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain Metabolomics Platform, Universitat Rovira i Virgili, IISRV, Reus, Spain Biosfer Teslab, Reus, Spain
Montse Guardiola Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain Research Unit on Lipids and Atherosclerosis, Sant Joan University Hospital, Rovira i Virgili University, IISPV, Reus, Spain
Josep Ribalta Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain Research Unit on Lipids and Atherosclerosis, Sant Joan University Hospital, Rovira i Virgili University, IISPV, Reus, Spain
Gemma Rojo-Martínez Department of Endocrinology and Nutrition, Hospital Regional Universitario de Málaga/Universidad de Málaga, Instituto de Investigación Biomedica de Málaga-IBIMA, Málaga, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain

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Rich oleocanthal and oleacein extra virgin olive oil and inflammatory and antioxidant status in people with obesity and prediabetes. The APRIL study: A randomised, controlled crossover study

BACKGROUND

Oleocanthal and oleacein are olive oil phenolic compounds with well known anti-inflammatory and anti-oxidant properties. The main evidence, however, is provided by experimental studies. Few human studies have examined the health benefits of olive oils rich in these biophenols. Our aim was to assess the health properties of rich oleocanthal and oleacein extra virgin olive oil (EVOO), compared to those of common olive oil (OO), in people with prediabetes and obesity.

METHODS

Randomised, double-blind, crossover trial done in people aged 40-65 years with obesity (BMI 30-40 kg/m²) and prediabetes (HbA1c 5.7-6.4%). The intervention consisted in substituting for 1 month the oil used for food, both raw and cooked, by EVOO or OO. No changes in diet or physical activity were recommended. The primary outcome was the inflammatory status. Secondary outcomes were the oxidative status, body weight, glucose handling and lipid profile. An ANCOVA model adjusted for age, sex and treatment administration sequence was used for the statistical analysis.

RESULTS

A total of 91 patients were enrolled (33 men and 58 women) and finished the trial. A decrease in interferon-γ was observed after EVOO treatment, reaching inter-treatment differences (P = 0.041). Total antioxidant status increased and lipid and organic peroxides decreased after EVOO treatment, the changes reaching significance compared to OO treatment (P < 0.05). Decreases in weight, BMI and blood glucose (p < 0.05) were found after treatment with EVOO and not with OO.

CONCLUSIONS

Treatment with EVOO rich in oleocanthal and oleacein differentially improved oxidative and inflammatory status in people with obesity and prediabetes.

Ambient air pollution and thyroid function in Spanish adults. A nationwide population-based study (Di@bet.es study)

BACKGROUND

Recent reports have suggested that air pollution may impact thyroid function, although the evidence is still scarce and inconclusive. In this study we evaluated the association of exposure to air pollutants to thyroid function parameters in a nationwide sample representative of the adult population of Spain.

METHODS

The Di@bet.es study is a national, cross-sectional, population-based survey which was conducted in 2008-2010 using a random cluster sampling of the Spanish population. The present analyses included 3859 individuals, without a previous thyroid disease diagnosis, and with negative thyroid peroxidase antibodies (TPO Abs) and thyroid-stimulating hormone (TSH) levels of 0.1-20 mIU/L. Participants were assigned air pollution concentrations for particulate matter <2.5μm (PM_2.5) and Nitrogen Dioxide (NO₂), corresponding to the health examination year, obtained by means of modeling combined with measurements taken at air quality stations (CHIMERE chemistry-transport model). TSH, free thyroxine (FT4), free triiodothyronine (FT3) and TPO Abs concentrations were analyzed using an electrochemiluminescence immunoassay (Modular Analytics E170 Roche).

RESULTS

In multivariate linear regression models, there was a highly significant negative correlation between PM_2.5 concentrations and both FT4 (p<0.001), and FT3 levels (p<0.001). In multivariate logistic regression, there was a significant association between PM_2.5 concentrations and the odds of presenting high TSH [OR 1.24 (1.01-1.52) p=0.043], lower FT4 [OR 1.25 (1.02-1.54) p=0.032] and low FT3 levels [1.48 (1.19-1.84) p=<0.001] per each IQR increase in PM_2.5 (4.86 μg/m³). There was no association between NO₂ concentrations and thyroid hormone levels. No significant heterogeneity was seen in the results between groups of men, pre-menopausal and post-menopausal women.

CONCLUSIONS

Exposures to PM_2.5 in the general population were associated with mild alterations in thyroid function.

Fatty liver index as a predictor for type 2 diabetes in subjects with normoglycemia in a nationwide cohort study

Our aim was to evaluate whether fatty liver index (FLI) is associated with the risk of type 2 diabetes (T2DM) development within the Spanish adult population and according to their prediabetes status; additionally, to examine its incremental predictive value regarding traditional risk factors. A total of 2260 subjects (Prediabetes: 641 subjects, normoglycemia: 1619 subjects) from the Di@bet.es cohort study were studied. Socio-demographic, anthropometric, clinical data and survey on habits were recorded. An oral glucose tolerance test was performed and fasting determinations of glucose, lipids and insulin were made. FLI was calculated and classified into three categories: Low (< 30), intermediate (30–60) and high (> 60). In total, 143 people developed diabetes at follow-up. The presence of a high FLI category was in all cases a significant independent risk factor for the development of diabetes. The inclusion of FLI categories in prediction models based on different conventional T2DM risk factors significantly increase the prediction power of the models when all the population was considered. According to our results, FLI might be considered an early indicator of T2DM development even under normoglycemic condition. The data also suggest that FLI could provide additional information for the prediction of T2DM in models based on conventional risk factors.

Association between the Mediterranean Diet and Metabolic Syndrome with Serum Levels of miRNA in Morbid Obesity

Background: The Mediterranean diet (MD) could be involved in the regulation of different miRNAs related to metabolic syndrome (MS). Methods: We analyzed the serum level of mir-let7a-5p, mir-21, mir-590, mir-107 and mir-192 in patients with morbid obesity and its association with the MD and MS. Results: There is an association between the adherence to MD and higher serum levels of mir-590. Mir-590 was lower in those patients who consumed >2 commercial pastries/week. Mir-let7a was lower in those who consumed ≥1 sweetened drinks, in those who consumed ≥3 pieces of fruit/day and in those who consumed less red than white meat. A lower mir-590 and mir-let7a, and a higher mir-192 level, were found in patients who met the high-density lipoprotein cholesterol (HDL) criterion of MS. A higher mir-192 was found in those patients who met the triglyceride criterion of MS and in those with type 2 diabetes (T2DM). Conclusions: There is an association between specific serum levels of miRNAs and the amount and kind of food intake related to MD. Mir-590 was positively associated with a healthy metabolic profile and type of diet, while mir-192 was positively associated with a worse metabolic profile. These associations could be suggestive of a possible modulation of these miRNAs by food.

Incidence of diabetes mellitus in Spain as results of the nation-wide cohort di@bet.es study

Our aim was to determine the incidence of type 2 diabetes mellitus in a nation-wide population based cohort from Spain (di@bet.es study). The target was the Spanish population. In total 5072 people older than 18 years,were randomly selected from all over Spain). Socio-demographic and clinical data, survey on habits (physical activity and food consumption) and weight, height, waist, hip and blood pressure were recorder. A fasting blood draw and an oral glucose tolerance test were performed. Determinations of serum glucose were made. In the follow-up the same variables were collected and HbA1c was determined. A total of 2408 subjects participated in the follow-up. In total, 154 people developed diabetes (6.4% cumulative incidence in 7.5 years of follow-up). The incidence of diabetes adjusted for the structure of age and sex of the Spanish population was 11.6 cases/1000 person-years (IC95% = 11.1–12.1). The incidence of known diabetes was 3.7 cases/1000 person-years (IC95% = 2.8–4.6). The main risk factors for developing diabetes were the presence of prediabetes in cross-sectional study, age, male sex, obesity, central obesity, increase in weight, and family history of diabetes. This work provides data about population-based incidence rates of diabetes and associated risk factors in a nation-wide cohort of Spanish population.

Tissue-Specific Phenotype and Activation of iNKT Cells in Morbidly Obese Subjects: Interaction with Adipocytes and Effect of Bariatric Surgery

BACKGROUND

The immune response of visceral adipose tissue (VAT) in obesity, in particular the role of invariant natural killer T (iNKT) cells, has not yet been fully elucidated.

OBJECTIVE

To characterize iNKT cells and its activation status in VAT and peripheral blood mononuclear cells (PBMC) in morbidly obese subjects (MO), and to analyze their association with metabolic parameters.

SUBJECTS AND METHODS

Twenty non-obese and 20 MO subjects underwent Roux-en-Y gastric bypass (RYGB) and were studied before and 6 months after RYGB. VAT and PBMC were obtained.

RESULTS

A decrease in VAT iNKT cells from MO was found, however, not in PBMC. Visceral adipocytes from MO presented increased CD1d expression (p = 0.032). MO presented an increase in early activated CD69+ iNKT cells in PBMC before RYGB (p < 0.001), but not after RYGB nor in VAT, and an increase in later activated CD25+ iNKT in VAT (p = 0.046), without differences in PBMC. The co-expression of early and later markers (CD69+CD25+) in iNKT cells was increased in MO in VAT (p = 0.050) and PBMC (p = 0.006), decreasing after RYGB (p = 0.050). CD69+ iNKT and CD69+CD25+ iNKT cells in PBMC after RYGB correlated negatively with glucose, insulin, and insulin resistance levels.

CONCLUSIONS

There is a tissue-specific phenotype and activation of iNKT cells in VAT in morbid obesity, which could be involved in VAT immunometabolism dysregulation. Also, the increase in CD1d expression could be to offset the lack of VAT iNKT cells.

Increased PON lactonase activity in morbidly obese patients is associated with impaired lipid profile

AIMS

The paraoxonase-1 (PON1) enzyme could play an important role in the anti-oxidant capacity of high-density lipoprotein. However, there are no studies which analyse the evolution of the three activities of PON1 (PON arylesterase, PON paraoxonase and PON lactonase) after Roux-en-Y Gastric Bypass (RYGB) in morbidly obese subjects. We analysed the association of PON concentration and activities with the evolution of morbidly obese subjects who underwent RYGB, and its relationship with biochemical variables and different atherogenic indices.

METHODS

Twenty-seven non-obese and 82 morbidly obese subjects were studied before and 6 months after RYGB.

RESULTS

Before RYGB, morbidly obese subjects had a lower PON1 concentration (P < 0.05) and higher PON lactonase activity (P < 0.001) than non-obese subjects, with no differences in PON arylesterase and PON paraoxonase activities. After RYGB, PON1 concentration (P < 0.05) and PON lactonase activity (P < 0.001) decreased with regard to the presurgery state. PON lactonase activity correlated with the atherogenic index of plasma before (r = 0.19, P = 0.047) and after RYGB (r = 0.27, P = 0.035). In different multiple lineal regression analysis models, presurgery PON lactonase activity was associated with total cholesterol (β = 0.909, P < 0.001), LDL (β = 0.632, P = 0.006) and DBP (β = 0.230, P = 0.030) (R²  = 0.295), postsurgery PON lactonase activity was associated with esterified cholesterol (β = 0.362, P = 0.011) (R²  = 0.131), and the change (Δ) in PON lactonase activity after RYGB was associated with Δesterified cholesterol (β = 0.304, P = 0.030) (R²  = 0.093).

CONCLUSIONS

PON lactonase activity is associated with the presence of morbid obesity and with an impaired lipid profile. All associations found could indicate the relationship between PON lactonase activity and the development of atherosclerosis.

miR-20b, miR-296, and Let-7f Expression in Human Adipose Tissue is Related to Obesity and Type 2 Diabetes

OBJECTIVE

This study aimed to analyze the potential association of different microRNA (miRNA) molecules with both type 2 diabetes (T2D) and obesity and determine their target genes.

METHODS

Quantitative PCR was used to analyze the miR-20b, miR-296, and Let-7f levels in human visceral and subcutaneous adipose tissues (ATs) in relation to obesity and T2D, miRTarBase 4.0 was used for validation of target genes, and the Protein Analysis Through Evolutionary Relationships (PANTHER) Classification System and the Database for Annotation, Visualization and Integrated Discovery (DAVID) were used to annotate the biological processes of the predicted targets.

RESULTS

In AT, miR-20b, miR-296, and Let-7f levels were significantly different between normoglycemic subjects and those with T2D. In visceral adipose tissue, miRNA levels were higher in normoglycemic/obesity samples than in T2D/obesity samples. miR-20b-miR-296 and Let-7f target genes that showed significant differences in both ATs in relation to obesity and T2D were CDKN1A, CX3CL1, HIF1A, PPP2R1B, STAT3, and VEGFA. These genes are known to be principally involved in the vascular endothelial growth factor (VEGF) and WNT pathways.

CONCLUSIONS

This study provides experimental evidence of the possible correlation between AT miR-20b-miR-296-Let-7f with obesity and T2D, which might involve vascular endothelial growth factor and WNT-dependent pathways that are regulated by six different genes, suggesting a novel signaling pathway that could be important for understanding the mechanisms underlying the AT dysfunction associated with obesity and T2D.

Ghrelin levels could be involved in the improvement of insulin resistance after bariatric surgery

BACKGROUND AND OBJECTIVE

Ghrelin is a gastrointestinal peptide involved in regulation of body weight and energy balance. However, its behavior after bariatric surgery and its relationship to insulin resistance are still controversial. A simultaneous assessment was made of the association between changes in ghrelin levels and different variables after three types of bariatric surgery.

PATIENTS AND METHODS

Ghrelin levels were measured in 103 morbidly obese subjects before and 6 months after bariatric surgery (Roux-en-Y gastric bypass (RYGB), biliopancreatic diversion of Scopinaro (BPD), and sleeve gastrectomy (SG)), and in 21 non-obese subjects.

RESULTS

Ghrelin levels increased after RYGB (p<0.05), were unchanged after BPD, and decreased after SG (p<0.05). The percent change in ghrelin levels (Δ-ghrelin) was associated to the type of surgery in a multiple linear regression model (p=0.017). When the same analysis was only performed in subjects in whom the gastric fundus was maintained (RYGB and BPD), Δ-ghrelin was negatively associated to Δ-HOMA-IR (p=0.001). In morbidly obese subjects who underwent RYGB and BPD, the odds ratio of a lower Δ-HOMA-IR in patients with Δ-ghrelin in the Q1 quartile versus those with Δ-ghrelin in the Q4 quartile was 8.74 (1.73-44.06) (p=0.009).

CONCLUSIONS

Changes in ghrelin levels after bariatric surgery are associated to the presence or absence of the gastric fundus. After bariatric surgery, the decrease in insulin resistance was associated to increased ghrelin levels in procedures in which the fundus is not excluded.

Dietary fatty acids modulate adipocyte TNFa production via regulation of its DNA promoter methylation levels

The factors regulating TNF alpha (TNFa) levels could be considered therapeutic targets against metabolic syndrome development. DNA methylation is a potent regulator of gene expression and may be associated with protein levels. In this study we investigate whether the effect of dietary fatty acids on TNFa released from adipocytes might be associated with modifications of the TNFa promoter DNA methylation status. A group of rats was assigned to three diets with a different composition of saturated, monounsaturated and polyunsaturated fatty acids. Samples of visceral adipose tissues were taken for adipocyte isolation, in which released TNFa levels were measured, and for methylation and expression studies. In addition, 3 T3-L1 cells were treated with palmitic, oleic and linoleic acids, with and without 5-Azacitydine (5-AZA). After treatments, cells and supernatants were included in the same analyses as rat samples. TNFa promoter methylation levels, gene expression and secretion were different according to the diets and fatty acid treatments associated with them. Cells treated with 5-AZA displayed higher TNFa levels than in the absence of 5-AZA, without differences between fatty acids. According to our results, dietary fatty acid regulation of adipocyte TNFa levels may be mediated by epigenetic modifications of the TNFa promoter DNA methylation levels.

Children whose diet contained olive oil had a lower likelihood of increasing their body mass index Z-score over 1 year

OBJECTIVE

Changes in eating habits may be influential in the ever-increasing rate of childhood obesity. Our aim was to determine whether those children who consume olive oil have a lower risk of weight gain compared with children who consume other oils.

DESIGN AND METHODS

The study included 18 girls and 74 boys, all aged 13-166 months. A survey was completed for each subject about eating habits and physical activity. A sample of subcutaneous adipose tissue was also obtained for cellular study. Data were recorded on the mean size of the adipocytes, the number of preadipocytes, and the concentration of particular fatty acids. The weight and height of the children were measured 13 months later.

RESULTS

The likelihood that after 1 year the children would have increased their body mass index (BMI) Z-score above the initial score was less in the children who consumed only olive oil (odds ratio (OR)=0.22; 95% confidence interval (CI): 0.08-0.63; P=0.005). These results remained after adjusting for age, physical activity and BMI (OR=0.19; 95% CI: 0.06-0.61; P=0.005) and after adjusting for age, physical activity and adipocyte volume (OR=0.15; 95% CI: 0.04-0.52; P=0.003).

CONCLUSIONS

Diets with mono unsaturated fatty acid (MUFA)-rich olive oil could reduce the risk of obesity in childhood.

Stearoyl-CoA desaturase-1 is associated with insulin resistance in morbidly obese subjects

Animal studies have revealed the association between stearoyl-CoA desaturase 1 (SCD1) and obesity and insulin resistance. However, only a few studies have been undertaken in humans. We studied SCD1 in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) from morbidly obese patients and their association with insulin resistance, sterol regulatory element binding protein-1 (SREBP-1) and ATPase p97, proteins involved in SCD1 synthesis and degradation. The insulin resistance was calculated in 40 morbidly obese patients and 11 overweight controls. Measurements were made of VAT and SAT SCD1, SREBP-1 and ATPase p97 mRNA expression and protein levels. VAT and SAT SCD1 mRNA expression levels in the morbidly obese patients were significantly lower than in the controls (P = 0.006), whereas SCD1 protein levels were significantly higher (P < 0.001). In the morbidly obese patients, the VAT SCD1 protein levels were decreased in patients with higher insulin resistance (P = 0.007). However, SAT SCD1 protein levels were increased in morbidly obese patients with higher insulin resistance (P < 0.05). Multiple linear regressions in the morbidly obese patients showed that the variable associated with the SCD1 protein levels in VAT was insulin resistance, and the variables associated with SCD1 protein levels in SAT were body mass index (BMI) and ATPase p97. In conclusion, these data suggest that the regulation of SCD1 is altered in individuals with morbid obesity and that the SCD1 protein has a different regulation in the two adipose tissues, as well as being closely linked to the degree of insulin resistance.

Jejunal wall triglyceride concentration of morbidly obese persons is lower in those with type 2 diabetes mellitus

The overproduction of intestinal lipoproteins may contribute to the dyslipidemia found in diabetes. We studied the influence of diabetes on the fasting jejunal lipid content and its association with plasma lipids and the expression of genes involved in the synthesis and secretion of these lipoproteins. The study was undertaken in 27 morbidly obese persons, 12 of whom had type 2 diabetes mellitus (T2DM). The morbidly obese persons with diabetes had higher levels of chylomicron (CM) triglycerides (P < 0.001) and apolipoprotein (apo)B48 (P = 0.012). The jejunum samples obtained from the subjects with diabetes had a lower jejunal triglyceride content (P = 0.012) and angiopoietin-like protein 4 (ANGPTL4) mRNA expression (P = 0.043). However, the apoA-IV mRNA expression was significantly greater (P = 0.036). The jejunal triglyceride content correlated negatively with apoA-IV mRNA expression (r = -0.587, P = 0.027). The variables that explained the jejunal triglyceride content in a multiple linear regression model were the insulin resistance state and the apoA-IV mRNA expression. Our results show that the morbidly obese subjects with diabetes had lower jejunal lipid content and that this correlated negatively with apoA-IV mRNA expression. These findings show that the jejunum appears to play an active role in lipid homeostasis in the fasting state.

Oxidative stress in severely obese persons is greater in those with insulin resistance

The postprandial state seems to have a direct influence on oxidative status and insulin resistance. We determined the effect of an increase in plasma triglycerides after a high-fat meal on oxidative stress in severely obese patients with differing degrees of insulin resistance. The study was undertaken in 60 severely obese persons who received a 60-g fat overload with a commercial preparation. Measurements were made of insulin resistance, the plasma activity of various antioxidant enzymes, the total antioxidant capacity (TAC) and the plasma concentration of thiobarbituric acid reactive substances (TBARS). The patients with greater insulin resistance had a lower plasma superoxide dismutase (SOD) activity (P < 0.05) and a greater glutathione peroxidase (GSH-Px) activity (P < 0.05). The high-fat meal caused a significant reduction in SOD activity and an increase in the plasma concentration of TBARS in all the patients. Only the patients with lower insulin resistance experienced a significant increase in plasma catalase activity (2.22 +/- 1.02 vs. 2.93 +/- 1.22 nmol/min/ml, P < 0.01), remaining stable in the patients with greater insulin resistance. These latter patients had a reduction in plasma TAC (6.92 +/- 1.93 vs. 6.29 +/- 1.80 mmol/l, P < 0.01). In conclusion, our results show a close association between the degree of insulin resistance and markers of oxidative stress, both before and after a high-fat meal. The postprandial state causes an important increase in oxidative stress, especially in severely obese persons with greater insulin resistance. However, we are unable to determine from this study whether there is first an increase in oxidative stress or in insulin resistance.

Changes in the serum composition of free-fatty acids during an intravenous glucose tolerance test

Recent studies suggest that measuring the free-fatty acids (FFA) during an intravenous glucose tolerance test (IVGTT) may provide information about the metabolic associations between serum FFA and carbohydrate and insulin metabolism. We evaluated the FFA profile during an IVGTT and determined whether this test changes the composition and concentration of FFA. An IVGTT was given to 38 severely obese persons before and 7 months after undergoing bariatric surgery and also to 12 healthy, nonobese persons. The concentration and composition of the FFA were studied at different times during the test. The concentration of FFA fell significantly faster during the IVGTT in the controls and in the severely obese persons with normal-fasting glucose (NFG) than in the severely obese persons with impaired-fasting glucose (IFG) or type 2 diabetes mellitus (T2DM) (P < 0.05). Significant differences were found in the time to minimum serum concentrations of FFA (control = NFG < IFG < T2DM) (P < 0.001). These variables improved after bariatric surgery in the three groups. The percentage of monounsaturated and n-6 polyunsaturated FFA in the control subjects and in the obese persons, both before and after surgery, decreased significantly during the IVGTT. In conclusion, during an IVGTT, severely obese persons with IFG or T2DM experienced a lower fall in the FFA than the severely obese persons with NFG and the controls, becoming normal after bariatric surgery.

Improved carbohydrate metabolism after bariatric surgery raises antioxidized LDL antibody levels in morbidly obese patients

OBJECTIVE

Antioxidized LDL (anti-oxLDL) antibodies have recently been suggested to be protective against the development of diabetes. We measured the changes in anti-oxLDL antibody levels in the inverse situation of improvement in carbohydrate metabolism.

RESEARCH DESIGN AND METHODS

The study was undertaken in 73 morbidly obese individuals, 21 of whom had type 2 diabetes, before and 7 months after they underwent bariatric surgery and in 11 healthy, nonobese individuals. Measurements were made of the area under the curve of glucose (AUC(Glu)) by an intravenous glucose tolerance test and of oxidized LDL (oxLDL) and IgG and IgM anti-oxLDL antibodies.

RESULTS

The morbidly obese patients with diabetes had significantly higher levels of oxLDL compared with the morbidly obese patients with normal fasting glucose and the control subjects and significantly lower levels of IgM anti-oxLDL antibodies. An inverse correlation was found between the levels of oxLDL and IgM anti-oxLDL antibodies (r = -0.352, P = 0.012). Although the levels of IgG and IgM anti-oxLDL antibodies rose after surgery, this increase was only significant in the diabetic patients, who experienced an improvement in their metabolic profile. Different multiple linear regression models showed that the AUC(Glu) was the main factor explaining the behavior of the levels of oxLDL and anti-oxLDL antibodies.

CONCLUSIONS

We found a close association between carbohydrate metabolism and IgM anti-oxLDL antibodies, which were significantly reduced in the morbidly obese patients with diabetes. The improvement in carbohydrate metabolism after bariatric surgery led to a significant increase in the levels of IgG and IgM anti-oxLDL antibodies.

Plasma visfatin concentrations in severely obese subjects are increased after intestinal bypass

OBJECTIVE

Visfatin has shown to be increased in obesity and in type 2 diabetes. The aim of this study was to determine the change in plasma visfatin in severely obese (SO) persons after weight loss following bariatric surgery in relation to glucose concentration.

RESEARCH METHODS AND PROCEDURES

Visfatin and leptin were studied in 53 SO persons (BMI, 54.4 +/- 6.8 kg/m(2)) before and 7 months after bariatric surgery and in 28 healthy persons (BMI, 26.8 +/- 3.8 kg/m(2)). All of the patients underwent bariatric surgery with biliopancreatic diversion or gastric bypass.

RESULTS

The pre-surgery levels of visfatin in the SO group were greater than in the control group (55.9 +/- 39.9 vs. 42.9 +/- 16.6 ng/mL, p = 0.024). This increase was significant in the SO group with impaired fasting glucose (63.4 +/- 36.6 ng/mL) and diabetes (60.0 +/- 46.0 ng/mL). SO patients with normal fasting glucose had similar levels of visfatin to the controls. Seven months after surgery, visfatin levels were significantly increased (84.8 +/- 32.8 ng/mL, p < 0.001). This increase was independent of the pre-surgical glucose levels. The type of bariatric surgery had no influence on visfatin levels. Post-surgical visfatin was significantly correlated with the post-surgery plasma concentrations of leptin (r = 0.39, p = 0.014).

DISCUSSION

Plasma levels of visfatin in the SO group were increased but only when accompanied by high glucose levels, even in the range of impaired fasting glucose. Bariatric surgery causes an increase in visfatin, which is correlated mainly with the changes produced in the leptin concentration.

Morbidly obese individuals with impaired fasting glucose have a specific pattern of insulin secretion and sensitivity: effect of weight loss after bariatric surgery

BACKGROUND

Obesity is often associated with hyper-secrection of insulin. Impaired fasting glucose (IFG) has recently been redefined as a fasting plasma glucose of 5.6-6.9 mmol/L. The aim of this study was to determine whether changes in insulin secretion in morbidly obese persons also commence with normal serum glucose levels.

METHODS

32 morbidly obese subjects were studied before and after bariatric surgery. Measurements were made of glucose tolerance (K(G)), insulin sensitivity (SI), first-phase insulin release and the disposition index (DI) from a frequently sampled intravenous glucose tolerance test.

RESULT

In morbidly obese subjects, the SI (P<0.01), DI (P<0.01) and first-phase insulin release (P<0.02) started changing with serum glucose levels considered to be normal (5.00-5.28 mmol/L). K(G) showed a clear slope according to the baseline glycemia status (P<0.05), and it was significantly related with the DI, both before (r=0.76, P<0.001) and after (r=0.57, P=0.002) surgery. Following surgery, all the variables significantly associated with insulin secretion and insulin sensitivity recovered significantly. The most significant changes occurred in morbidly obese individuals with IFG.

CONCLUSIONS

Morbidly obese subjects show slopes of insulin sensitivity and insulin secretion in accordance with their baseline serum glucose levels. The fall in first-phase insulin release begins when serum glucose values are considered normal. Morbidly obese persons with the IFG phenotype have a specific pattern of insulin sensitivity and insulin secretion. K(G) clearly discriminates the clinical phenotypes, depending on baseline serum glucose levels.