Fernando Cardona

Adipose tissue gene expression of factors related to lipid processing in obesity.

Background Adipose tissue lipid storage and processing capacity can be a key factor for obesity-related metabolic disorders such as insulin resistance and diabetes. Lipid uptake is the first step to adipose tissue lipid storage. The aim of this study was to analyze the gene expression of factors involved in lipid uptake and processing in subcutaneous (SAT) and visceral (VAT) adipose tissue according to body mass index (BMI) and the degree of insulin resistance (IR). Methods and Principal Findings VLDL receptor (VLDLR), lipoprotein lipase (LPL), acylation stimulating protein (ASP), LDL receptor-related protein 1 (LRP1) and fatty acid binding protein 4 (FABP4) gene expression was measured in VAT and SAT from 28 morbidly obese patients with Type 2 Diabetes Mellitus (T2DM) or high IR, 10 morbidly obese patients with low IR, 10 obese patients with low IR and 12 lean healthy controls. LPL, FABP4, LRP1 and ASP expression in VAT was higher in lean controls. In SAT, LPL and FABP4 expression were also higher in lean controls. BMI, plasma insulin levels and HOMA-IR correlated negatively with LPL expression in both VAT and SAT as well as with FABP4 expression in VAT. FABP4 gene expression in SAT correlated inversely with BMI and HOMA-IR. However, multiple regression analysis showed that BMI was the main variable contributing to LPL and FABP4 gene expression in both VAT and SAT. Conclusions Morbidly obese patients have a lower gene expression of factors related with lipid uptake and processing in comparison with healthy lean persons.

Intermittent hypoxia alters gut microbiota diversity in a mouse model of sleep apnoea

We assessed whether intermittent hypoxia, which emulates one of the hallmarks of obstructive sleep apnoea (OSA), leads to altered faecal microbiome in a murine model. In vivo partial pressure of oxygen was measured in colonic faeces during intermittent hypoxia in four anesthetised mice. 10 mice were subjected to a pattern of chronic intermittent hypoxia (20u2005s at 5% O2 and 40u2005s at room air for 6u2005h·day−1) for 6u2005weeks and 10 mice served as normoxic controls. Faecal samples were obtained and microbiome composition was determined by 16S rRNA pyrosequencing and bioinformatic analysis by Quantitative Insights into Microbial Ecology. Intermittent hypoxia exposures translated into hypoxia/re-oxygenation patterns in the faeces proximal to the bowel epithelium (<200u2005μm). A significant effect of intermittent hypoxia on global microbial community structure was found. Intermittent hypoxia increased the α-diversity (Shannon index, p<0.05) and induced a change in the gut microbiota (ANOSIM analysis of β-diversity, p<0.05). Specifically, intermittent hypoxia-exposed mice showed a higher abundance of Firmicutes and a smaller abundance of Bacteroidetes and Proteobacteria phyla than controls. Faecal microbiota composition and diversity are altered as a result of intermittent hypoxia realistically mimicking OSA, suggesting the possibility that physiological interplays between host and gut microbiota could be deregulated in OSA. Faecal microbiota composition and diversity are altered due to intermittent hypoxia mimicking OSA in a murine model http://ow.ly/ERjA9

Monounsaturated n-9 fatty acids and adipocyte lipolysis in rats.

To investigate the role of the monounsaturated n-9 fatty acids (MUFA) in the lipolytic activity of adipocytes, a study was carried out in which an increase in MUFA was produced in the tissues by two different methods; by the dietary enrichment of oleic acid or by producing an essential fatty acid deficiency syndrome. For this, forty-five male Sprague-Dawley rats were fed with a normal-energy diet and were subdivided into three groups. The diets varied in the type of dietary fat; palmitic acid, olive oil, or soyabean oil+palmitic acid. At the end of the study measurements were taken of weight, plasma leptin, tissue concentration of fatty acids, fat-cell size in the epididymal and the omental adipose tissues, adipocyte lipolytic activity of both tissues after stimulation with adrenaline, and the capacity of insulin to inhibit lipolysis. The baseline and adrenaline-stimulated lipolytic activity were greater and the anti-lipolytic capacity of insulin lower in the animals undergoing an increase in MUFA in the tissues (palmitic-acid and olive-oil diets). The area under the curve of glycerol, used as an indicator of lipolytic activity, was positively correlated with the concentration of MUFA and negatively with polyunsaturated fatty acids in the adipose tissues. It is concluded that an increase in tissue MUFA, however obtained, induces an increase in lipolytic activity.

The -1131T>C SNP of the APOA5 gene modulates response to fenofibrate treatment in patients with the metabolic syndrome: a postprandial study.

OBJECTIVEnApolipoprotein A5 is a key gene controlling VLDL synthesis and hydrolysis and is the target of the main pharmacological agent to lower triglycerides (fibrates). We hypothesised that variability in the promoter of the APOA5 gene may affect the individual response to fibrate therapy, in both the fasting and postprandial states.nnnMETHODSnWe selected 50 subjects with the metabolic syndrome who also had important increase in fasting triglycerides. A subgroup of 36 patients underwent lipid-lowering treatment with 160 mg/day of fenofibrate (Secalip) for 3 months. The participants underwent a 60 g fat overload with a commercial preparation, after which we assessed the influence of the -1131T>C APOA5 SNP on the postprandial response.nnnRESULTSnCompared with non-carriers, the C allele carriers had significantly higher triglyceride levels at baseline (54.87%), and at 3h (61.08%) and 4h (68.35%). Other lipid parameters were not affected by the APOA5 genotype. Our results indicate that carriers of the -1131C allele had a better response to fenofibrate treatment (reduction in triglyceride levels of 40.33% at baseline, P=0.018; and postprandially, 37.64% at 3h, P=0.028 and 42.58% at 4h after the high-fat meal, P=0.018) than wild-type subjects (30.91% decrease at baseline, P<0.001; and 26.61% at 3h P=0.005 and 22.95% at 4h P=0.033 after the high-fat meal).nnnCONCLUSIONnThus, the treatment for patients with the metabolic syndrome and elevated plasma triglyceride levels may vary according to whether they carry the APOA5 -1131T>C polymorphism.

Effect of apolipoprotein C3 and apolipoprotein A1 polymorphisms on postprandial response to a fat overload in metabolic syndrome patients.

OBJECTIVESnApolipoprotein C-III (APOC3) is a component of triglyceride rich lipoproteins, and SstI polymorphism has been associated with hypertriglyceridemia. Apolipoprotein A-I (APOA1) is the major component of HDL and MspI polymorphism has been associated with APOA1 and HDL-C levels. Thus, we study the influence of these polymorphisms in the postprandial response in metabolic syndrome (MS).nnnDESIGN AND METHODSn73 MS patients and 21 healthy subjects underwent a fat overload, with measurements of their fasting and postprandial lipid profile. The APOC3 SstI and the APOA1MspI polymorphisms were genotyped.nnnRESULTSnNo significant differences were found in the lipid profile with respect to the MspI genotype. Patients with the S2S2 APOC3 genotype had significantly higher fasting and postprandial triglyceride levels and postprandial APOC3 and chylomicron-triglyceride levels compared with the other SstI APOC3 genotypes.nnnCONCLUSIONSnHomozygosity for the minor allele of the APOC3 SstI polymorphism was associated to a worse postprandial response in MS patients.

Particular characteristics of the metabolic syndrome in patients with morbid obesity

BACKGROUNDnCriteria for the diagnosis of the metabolic syndrome are currently being reconsidered, as their usefulness is not the same for all phenotypes in relation to the risk of cardiovascular disease.nnnAIMnWe analyzed the changes in metabolic parameters after a fat overload in different groups of patients.nnnMATERIALS AND METHODSnThe study included 20 healthy persons, 30 metabolic syndrome patients without morbid obesity, 80 metabolic syndrome patients with morbid obesity and 16 patients with morbid obesity without the metabolic syndrome. All the participants received a fat overload of 60g. Measurements were made before the overload and 3h afterwards of triglycerides, free fatty acids, insulin and uric acid.nnnRESULTSnMetabolic syndrome patients with morbid obesity had a lower waist-to-hip ratio, and lower plasma free fatty acid and triglycerides levels at baseline and after the overload than patients without morbid obesity. Plasma uric acid levels rose after the fat overload in the metabolic syndrome patients who had morbid obesity but not in the patients without morbid obesity. A positive relation was found between plasma triglycerides and free fatty acid levels in all the patients but not in the controls after the fat overload. A positive relation was also found between uric acid and insulin levels in the metabolic syndrome patients with morbid obesity.nnnCONCLUSIONSnMetabolic syndrome patients with and without morbid obesity presented different metabolic characteristics. This suggests that there are 2 different clinical phenotypes, both grouped under the metabolic syndrome umbrella.

Influence of a fat overload on lipogenic regulators in metabolic syndrome patients.

Several epidemiological studies have related an increase of lipids in the postprandial state to an individual risk for the development of CVD, possibly due to the increased plasma levels of TAG and fatty acids (FA) through enzymes of FA metabolism. The interaction between nutrition and the human genome determines gene expression and metabolic response. The aim of the present study was to evaluate the influence of a fat overload on the gene mRNA levels of lipogenic regulators in peripheral blood mononuclear cells (PBMC) from patients with the metabolic syndrome. The study included twenty-one patients with criteria for the metabolic syndrome who underwent a fat overload. Measurements were made before and after the fat overload of anthropometric and biochemical variables and also the gene mRNA levels of lipogenic factors. The main results were that the fat overload led to an increased mRNA levels of sterol regulatory element binding protein-1 (SREBP1), retinoid X receptor α (RXRα) and liver X receptor α (LXRα) in PBMC, and this increase was associated with the FA synthase (FASN) mRNA levels. We also found that TAG levels correlated with FASN mRNA levels. In addition, there was a positive correlation of SREBP1 with RXRα and of LXRα with the plasma lipoperoxide concentration. The fat overload led to an increase in regulators of lipogenesis in PBMC from patients with the metabolic syndrome.

Anti‐oxidized LDL antibody levels are reduced in women with hypertension

Backgroundu2002 Previous studies have suggested that hypertension may be associated with increased oxidized low‐density lipoprotein (LDL). Increased in vitro oxidizability of LDL or elevated titers of anti‐oxidized LDL antibodies have been shown in subjects with essential hypertension. However, the relationship between oxidized LDL and hypertension is equivocal. We examined the association between hypertension and levels of IgG anti‐oxidized LDL antibodies in a group of women from the general population.