Prevalence of metabolic syndrome in urban Colombian adolescents aged 10-16 years using three different pediatric definitions.

The aim of this study was to evaluate the metabolic syndrome (MetS) prevalence in adolescents using three different definitions for this age group. The evaluated sample consisted of 718 male and 743 female adolescents. Definitions by Cook et al., de Ferranti et al. and International Diabetes Federation (IDF) for adolescents were used to estimate the prevalence of MetS. The prevalence of MetS was 8.5, 2.5 and 1.2% by de Ferranti et al., Cook et al. and IDF definitions, respectively. High fasting glucose component had the lower prevalence whereas high triglycerides levels component was the most prevalent. In obese adolescents, the prevalence of MetS was higher. MetS classification in adolescents strongly depends on the definition chosen. Further research is required for the evaluation of the current definitions (multicentric studies), and for addition or design of new and useful criteria.

C-reactive protein, waist circumference, and family history of heart attack are independent predictors of body iron stores in apparently healthy premenopausal women.

Ferritin levels have been associated with metabolic syndrome and insulin resistance. The aim of the present study was to evaluate the prediction of ferritin levels by variables related to cardiometabolic disease risk in a multivariate analysis. For this aim, 123 healthy women (72 premenopausal and 51 posmenopausal) were recruited. Data were collected through procedures of anthropometric measurements, questionnaires for personal/familial antecedents, and dietary intake (24-h recall), and biochemical determinations (ferritin, C reactive protein (CRP), glucose, insulin, and lipid profile) in blood serum samples obtained. Multiple linear regression analysis was used and variables with no normal distribution were log-transformed for this analysis. In premenopausal women, a model to explain log-ferritin levels was found with log-CRP levels, heart attack familial history, and waist circumference as independent predictors. Ferritin behaves as other cardiovascular markers in terms of prediction of its levels by documented predictors of cardiometabolic disease and related disorders. This is the first report of a relationship between heart attack familial history and ferritin levels. Further research is required to evaluate the mechanism to explain the relationship of central body fat and heart attack familial history with body iron stores values.

Influencia del origen etnico sobre la sensibilidad a insulina, perfil lipidico en personas entre 18 y 39 años / Influence of ethnic origen on insulin sensivity, lipid profile of persons with 18 and 39 years old

Se observa en ciertos grupos étnicos, un riesgo alto de desarrollar enfermedades crónicas no transmisibles (ECnT) cuando los sujetos son sometidos a dieta de alta densidad calórica y estilo de vida sedentaria. Este hecho se asocia al desarrollo de resistencia a insulina en estas mismas poblaciones. La resistencia a insulina está ligada a enfermedad cardiovascular posiblemente a través de cambios en el metabolismo de lípidos. El objetivo de este estudio fue evaluar la asociación entre el grupo étnico con sensibilidad a insulina, características bioquímicas y antropométricas.A 113 sujetos entre 18-39 años se les realizó encuesta de antecedentes familiares, antropometría, test de tolerancia a insulina, genotipificación ApoE y determinación de glucosa y lípidos. Los resultados fueron sometidos a Análisis de Regresión Múltiple para cada uno de los grupos étnicos. TAG se asocian significantemente con edad, sensibilidad a insulina e IMC en etnia blanca (p=0.016), mestiza (p=0.040) e indígena (p=0.040). Sin relación significante con colesterol total y col-HDL, etnia, IMC, edad y sensibilidad a insulina. Resistentes a insulina 44 por ciento, porcentaje relativamente alto considerando que es un grupo de personas jóvenes. La distribución del genotipo ApoE es: 2/ 3=7 por ciento, 3/3=72 por ciento, 3/4=17 por ciento y 4/4=2 por ciento con alto porcentaje del alelo E4. Los datos sugieren que la sensibilidad a insulina es independiente del grupo étnico, IMC y edad. El análisis estadístico permite concluir: que en la etnia blanca la concentración de TAG está correlacionada con la sensibilidad a insulina, en los mestizos se correlaciona con el IMC y en los indígenas con la edad y sensibilidad a insulina. En el grupo étnico negro ninguna de estas variables está correlacionada con los TAG. En cada etnia existen situaciones de riesgo para perfiles alterados de lípidos que se sabe están asociados al desarrollo temprano de ECNT. Los resultados de este estudio pueden ser utilizados como base para el diseño de estrategias de prevención para mejorar la calidad de vida en el adulto

Antigenicity and immunogenicity of multiple antigen peptides (MAP) containing P. vivax CS epitopes in Aotus monkeys.

Using linear synthetic peptides corresponding to the Plasmodium vivax circumsporozoite (CS) protein of the common type, we have identified several T and B-cell epitopes recognized by human individuals. Three T-cell epitopes studied (p6) from the amino, (p11) from the central and (p25) from the carboxyl regions, were widely recognized by lymphocytes of immune donors. A series of six peptides, in addition to p11, representing the central repeat domain of the CS(p11-p17) protein were used in ELISA assays to map the B-cell epitopes of this region. P11 was the peptide most frequently recognized by sera containing antibodies to the homologous CS protein as determined by IFAT. The sequences corresponding to peptides p6, p11 and P25 as well as that representing a universal T-cell epitope derived from the tetanus toxin were used to assemble eight different Multiple Antigen Peptides (MAP). The immunogenicity of these MAP was analysed in Aotus monkeys. Groups of two animals were immunized with each MAP and both antibody response, T-lymphocyte proliferation and in vitro gamma-IFN production were evaluated. Two MAPs containing the same B-cell epitope and either a promiscuous CS-protein derived T-cell epitope (p25) or the tetanus toxin epitope (p-tt30) proved to be the most immunogenic and induced high levels of anti-peptide antibodies that recognized the native protein. Except for animals immunized with MAP VII, there was no correlation between antibody levels, lymphocyte proliferation or gamma-IFN production in vitro. The broad recognition of these epitopes by individuals which had been exposed to malaria, the capacity of these MAPs to induce antibodies, recognize the cognate protein, and in vitro gamma-IFN production encourages further analyses of the potential of these proteins as malaria vaccine candidates for human use.

Serum factors inhibitory for in vitro development of Plasmodium falciparum blood-stage parasites.

Sera from 29 individuals residing in a malaria-endemic region of Colombia were evaluated by an inhibition assay for their capacity to retard the growth of Plasmodium falciparum in vitro. The inhibitory activity was found to be independent of antibody activity. Furthermore, the degree of inhibition of parasite development was variable, depending on the parasite isolate used for the assay and the season of malaria transmission. We selected sera with high inhibitory activity and carried out partial analytical characterization by anion exchange fast protein liquid chromatography (FPLC) to identify the chemical nature of the inhibitory factor(s). The results suggested that the in vitro inhibitory activity might result from the additive effect of different molecules. It appears that these molecules could be non-specifically induced by stimulation of the immune system, they seem to play a role in the immunity to malaria.

Immunogenicity of multiple antigen peptides containing Plasmodium vivax CS epitopes in BALB/c mice.

Multiple antigen peptide systems (MAPs) allow the incorporation of various epitopes in to a single synthetic peptide immunogen. We have characterized the immune response of BALB/c mice to a series of MAPs assembled with different B and T cell epitopes derived from the Plasmodium vivax circumsporozoite (CS) protein. A B-cell epitope from the central repeat domain and two T-cell epitopes from the amino and carboxyl flanking regions were used to assembled eight different MAPs. An additional universal T cell epitope (ptt-30) from tetanus toxin protein was included. Immunogenicity in terms of antibody responses and in vitro T lymphocyte proliferation was evaluated. MAPs containing B and T cell epitopes induced high titers of anti-peptides antibodies, which recognized the native protein on sporozoites as determined by IFAT. The antibody specificity was also determined by a competitive inhibition assay with different MAPs. A MAP containing the B cell epitope (p11) and the universal epitope ptt-30 together with another composed of p11 and the promiscuous T cell epitope (p25) proved to be the most immunogenic. The strong antibody response and specificity for the cognate protein indicates that further studies designed to assess the potential of these proteins as human malaria vaccine candidates are warranted.

A conserved region of the MSP-1 surface protein of Plasmodium falciparum contains a recognition sequence for erythrocyte spectrin.

The major surface protein MSP-1 of Plasmodium falciparum blood-stage malaria parasites contains notably conserved sequence blocks with unknown function. The recombinant protein 190L, which represents such a block, exhibits a high affinity for red blood cell membranes. We demonstrate that both 190L and native MSP-1 protein bind to the inner red blood cell membrane skeleton protein spectrin. By using overlapping peptides covering the 190L molecule, we show that the spectrin contact site of 190L is included in a linear sequence of 30 amino acid residues. Association of 190L with naturally occurring spectrin deficient red blood cells is drastically reduced. In the same cells parasite invasion is normal, but the intracellular parasite development arrests late in the trophozoite stage. A similar situation arises when synthetic peptides covering the spectrin recognition sequence of 190L are added to P.falciparum cultures. These data and the cellular localization of MSP-1 suggest the possibility that MSP-1 associates with spectrin under natural conditions.

Human recognition of T cell epitopes on the Plasmodium vivax circumsporozoite protein.

In order to identify T cell epitopes recognized by human in the Plasmodium vivax circumsporozoite protein, 28 overlapping synthetic peptides spanning the entire circumsporozoite protein were tested for their ability to stimulate proliferation of PBMC from 22 adults living in a malaria-endemic area of the Colombian Pacific Coast and from four individuals who never had a history of malaria infection. In addition, BALB/c mice were immunized with pools of peptides, and their lymph node cells were stimulated in vitro with individual peptides. Four epitopes were recognized by human lymphocytes but not all of them by mice. One of the epitopes was located inside the central repetitive B cell immunodominant domain. Several of the variants of the repeats were recognized by about one-third of the studied individuals. Another T cell epitope was located in the amino terminus and the other two in the carboxyl region. Peptides were recognized by both immune and nonimmune donors. Some of them were frequently recognized suggesting a lack of genetic restriction, whereas some others were recognized by only a few individuals but induced strong proliferation. These epitopes may be of potential value for a malaria subunit vaccine.