Paulina Bustos

Metabolic syndrome in obese adolescents.

Bustos P, Saez K, Gleisner A, Ulloa N, Calvo C, Asenjo S. Metabolic syndrome in obese adolescents.

Β-Sitosterol modulation of monocyte-endothelial cell interaction : A comparison to female hormones

OBJECTIVE To investigate the effect of beta-sitosterol, 17beta-estradiol and progesterone on oxidized LDL (oxLDL)-stimulated human umbilical venous endothelial cell (HUVEC) expression of intercellular adhesion molecule-1 (ICAM-1), THP-1 monocyte chemotactic activity, migration and adhesion of THP-1 cells co-cultured with HUVECs. METHODS ICAM-1 expression was determined by immunofluorescence in HUVEC monolayers treated with LDL or oxLDL and 17beta-estradiol, progesterone or beta-sitosterol. Monocyte chemotactic activity was performed in Transwell chambers by culturing HUVECs with different stimuli and steroids, THP-1 cells labeled with [(3)H] thymidine were added to the upper chamber and the radioactivity was measured. Migration assays were performed using Transwell chambers but monocytes were labeled with BCECF-AM and THP-1 cells adhered to HUVECs were visualized by fluorescence microscopy. MCP-1 was quantified by ELISA. RESULTS ICAM-1 expression was inhibited by beta-sitosterol alone, when combined with 17beta-estradiol or progesterone, or with both hormones. It was shown that 7.5 microM beta-sitosterol decreased migration and adhesion of THP-1 cells to HUVECs cultured in the presence of oxLDL. This effect was also observed in HUVEC cultures in the presence of beta-sitosterol, the 17beta-estradiol and progesterone mixture, and in the presence of the two hormones. It was shown that 7.5 microM beta-sitosterol significantly inhibited chemotaxis of [(3)H] thymidine labeled THP-1 cells in oxLDL-stimulated HUVEC cultures. MCP-1 concentrations in the supernatants of oxLDL-stimulated HUVEC cultures were inhibited by 7.5 microM beta-sitosterol as well as by progesterone and the mixture of the two female hormones.

Expression and localization of an agmatinase-like protein in the rat brain

Agmatinase catalyzes the hydrolysis of agmatine into putrescine and urea, and agmatine (decarboxylated l-arginine) plays several roles in mammalian tissues, including neurotransmitter/neuromodulatory actions in the brain. Injection of agmatine in animals produces anticonvulsant, antineurotoxic and antidepressant-like actions. Information regarding the enzymatic aspects of agmatine metabolism in mammals, especially related to its degradation, is relatively scarce. The explanation for this is the lack of enzymatically active preparations of mammalian agmatinase. Recently, we have cloned a protein from a cDNA rat brain library having agmatinase activity although its amino acid sequence greatly differs from all known agmatinases, we called agmatinase-like protein. In this work, we analyzed the expression of this enzyme in the rat brain by means of RT-PCR and immunohistochemical analysis using a polyclonal antibody generated against the recombinant agmatinase-like protein. The agmatinase-like protein was detected in the hypothalamus in glial cells and arcuate nucleus neurons, and in hippocampus astrocytes and neurons, but not in brain cortex. In general, detected localization of agmatinase-like protein coincides with that described for its substrate agmatine and our results help to explain several reported effects of agmatine in the brain. Concretely, a role in the regulation of intracellular concentrations of the neurotransmitter/neuromodulator agmatine is suggested for the brain agmatinase-like protein.

FTO gene is related to obesity in Chilean Amerindian children and impairs HOMA-IR in prepubertal girls.

The objective of this study was to investigate the allelic frequency of the fat mass and obesity‐associated (FTO) gene (rs9939609) and its influences on obesity and metabolic risk biomarkers in a cohort of normal weight and obese Chilean children determining its ethnicity.

Lipoprotein composition in children and adolescents with type 1 diabetes mellitus

Atherosclerotic cardiovascular diseases are the major causes of morbidity and mortality in patients with diabetes mellitus. Both quantitative and qualitative abnormalities of lipo-proteins are associated with the development of atherogenesis. In this study, the prevalence of dyslipidemia and the relative levels of glycosylated lipoproteins in 20 children and adolescents with type 1 diabetes mellitus were determined. Lipid profile, apolipoproteins A-I and B, Lp(a) and LpA-I in plasma were assayed. LpB and glycosylated HDL and LDL were evaluated by ELISA. Diabetic patients and controls had normal lipid profiles, but the diabetic group showed significantly higher LpA-I and lower LpA-I:A-II concentrations than controls. The diabetic group showed a significantly higher glycosylation level of HDL than controls and did not show a statistical difference for glycosylated LDL. No significant correlation between glycosylated lipoproteins, glycemia or HbA1c was found. In conclusion, these results suggest that type 1 diabetic patients develop important qualitative lipid abnormalities.

Unsaturated fatty acids and insulin resistance in childhood obesity.

Abstract Objective: Obesity is characterized by increased levels of plasma free fatty acids (FFAs) that interfere with insulin signaling. The aim of our study was to assess the FFA profile in obese children and adolescents and to determine their relation with different degrees of insulin resistance. Methods: A transversal study was conducted of 51 children and adolescents (mean age, 11.7±1.6 years; 47% males) with obesity (body mass index ≥95 percentile). Anthropometric, clinical, and biochemical parameters were assessed. Insulin resistance was determined using the homeostasis model assessment of insulin resistance (HOMA-IR) index. Plasma fatty acids were quantified by high-performance liquid chromatography with heptadecanoic acid as the internal standard. Results: The mean concentration of myristic acid, linoleic acid, palmitic acid, oleic acid, stearic acid, and total fatty acids was 9.3±2.2, 86.5±38.3, 93.0±35.5, 177.0±83.6, 48.5±14.9, and 414.3±160.9 μmol/L, respectively. Total fatty acids and unsaturated fatty acids such as oleic acid and linoleic acid showed an inverse significant correlation with insulin resistance. Children with high insulin resistance (HOMA-IR >2.5) showed a decrease in unsaturated fatty acids compared with children having a HOMA-IR of <2.5. There were no changes in saturated fatty acid concentrations between those groups. Conclusions: A decrease in unsaturated fatty acids was correlated with insulin resistance in childhood obesity.

Development, characterization and in vitro evaluation of biodegradable rhein-loaded microparticles for treatment of osteoarthritis

&NA; Rhein is an active metabolite of the drug diacerein, whose anti‐inflammatory properties have been demonstrated in both in vitro and in vivo models. However, the low oral bioavailability of rhein has limited its utility as a potential treatment of osteoarthritis (OA), a chronic inflammatory disease. In order to overcome this limitation, the aim of this work was the development of a drug delivery system intended for intra‐articular administration of rhein, based on polymeric biodegradable PLGA microparticles (MPs) loaded with the drug. The MPs, prepared by the emulsion–solvent evaporation technique were characterized in terms of several parameters including morphology, encapsulation efficiency, molecular interactions between components of the formulation and in vitro release profiling. Furthermore, cell‐based in vitro studies were performed to evaluate the cytotoxicity of the formulations and their effect on the release of inflammatory markers including pro‐inflammatory cytokines and reactive oxygen species (ROS). Scanning electron microscopy demonstrated that the prepared MPs exhibited an almost spherical shape with smooth surface. The size distribution of the prepared MPs ranged between 1.9 and 7.9 &mgr;m, with mean diameter of 4.23 ± 0.87 &mgr;m. The optimal encapsulation efficiency of rhein was 63.8 ± 3.0%. The results of powder X‐ray diffraction and differential scanning calorimetry studies demonstrated that the active ingredient is partially the crystalline state, dispersed in the polymer matrix. This outcome is somewhat reflected in the release kinetics of rhein from the MPs. The cytotoxicity evaluation, carried out in macrophages derived from THP‐1 cells, showed that both rhein‐loaded MPs and unloaded MPs did not significantly affect the cell viability at MP concentrations up to 13.8 &mgr;M. In lipopolysaccharide‐activated macrophages, the rhein‐loaded MPs significantly decreased the production of interleukin‐1&bgr; (IL‐1&bgr;) and (ROS), when compared to the unloaded MPs. In conclusion, the results of this preliminary study suggest that an MP‐based formulation of rhein could be tested in animal models of inflammation, aiming for an injectable commercial product capable of providing a therapeutic solution to patients suffering from chronic joint diseases. Graphical abstract Figure. No caption available.

Development of biodegradable methylprednisolone microparticles for treatment of articular pathology using a spray-drying technique

In this work, microparticles were prepared by spray-drying using albumin, chondroitin sulfate, and hyaluronic acid as excipients to create a controlled-release methylprednisolone system for use in inflammatory disorders such as arthritis. Scanning electron microscopy demonstrated that these microparticles were almost spherical, with development of surface wrinkling as the methylprednisolone load in the formulation was increased. The methylprednisolone load also had a direct influence on the mean diameter and zeta potential of the microparticles. Interactions between formulation excipients and the active drug were evaluated by x-ray diffraction, differential scanning calorimetry, and thermal gravimetric analysis, showing limited amounts of methylprednisolone in a crystalline state in the loaded microparticles. The encapsulation efficiency of methylprednisolone was approximately 89% in all formulations. The rate of methylprednisolone release from the microparticles depended on the initial drug load in the formulation. In vitro cytotoxic evaluation using THP-1 cells showed that none of the formulations prepared triggered an inflammatory response on release of interleukin-1β, nor did they affect cellular viability, except for the 9.1% methylprednisolone formulation, which was the maximum test concentration used. The microparticles developed in this study have characteristics amenable to a therapeutic role in inflammatory pathology, such as arthritis.

Monoclonal antibodies to human apolipoproteins: application to the study of high density lipoprotein subpopulations.

We produced, selected and cloned hybridomas that secrete monoclonal antibodies against human apolipoprotein (apo) A-I. All of the antibodies corresponded to the IgG(1) subclass and were named 1C11, 2B4, 2C10, 7C5, 8A4 and 8A5. The antibodies were characterized by their reactivity with whole lipoproteins, apolipoproteins, synthetic peptides and fragments generated by cleavage of the apo A-I. Three of the monoclonal antibodies studied (2B4, 2C10 and 7C5) were similarly inhibited by an amino-terminal peptide (amino acid sequence 1-20) of apo A-I, whereas antibodies 1C11, 8A4 and 8A5 had no reaction. Other results show that monoclonal antibody 1C11 recognizes an epitope located between amino acids 135-148. We evaluated the monoclonal antibody 8A4 against different HDL subpopulations by competitive displacement analysis and it showed a similar reactivity with the HDL particles: LpA-I and LpA-I:A-II. This antibody was used to standardize a sandwich ELISA to quantitate LpA-I in plasma. We conclude that these monoclonal antibodies are relevant for the study of apo A-I epitope expression and for quantitating apo A-I containing lipoparticles.

Efecto del estado nutricional neonatal en el riesgo de síndrome metabólico en niños obesos de 2 comunas de la Región del Bío-Bío

: A nested case/control study in a sample of 410 obese school children aged 10 to 16 years (57% males) was performed. The dichotomous response variable was the presence of MS defined as International Diabetes Federation (IDF) or Cook’s criteria. The ex-posure variable was having NPI < percentile (p) 10.BACKGROUND Neonatal malnutrition defined by birth weight (BW) is a risk factor for obesity and cardio-metabolic diseases in adults. Neonatal ponderal index (NPI) may have better diagnostic value than BW to establish nutritional status. AIM To determine the effect of neonatal nutritional status, established by the three NPI curves available in Chile, on the risk of Metabolic Syndrome (MS) in obese school children. MATERIAL AND METHODS A nested case/control study in a sample of 410 obese school children aged 10 to 16 years (57% males) was performed. The dichotomous response variable was the presence of MS defined as International Diabetes Federation (IDF) or Cooks criteria. The exposure variable was having NPI < percentile (p) 10. RESULTS The frequency of MS was 36 and 39% according to the IDF and Cook criteria, respectively. The proportion of children with neonatal malnutrition exceeded 20%. A significantly increased risk for MS was only found when PNI was defined according to Lagoss Table and MS was defined using IDF criteria. Having a PNI > p90, however, showed a trend towards a reduced risk of MS, which only reached significance using Lagoss Table and Cooks Criteria. CONCLUSIONS Neonatal malnutrition defined by NPI is common in obese school children. The condition of neonatal under nutrition defined as PNI < p10 may be a risk factor for developing MS. Instead, having a NPI > p90 could be protective.