Comparative analysis of anthropometric indicators for diagnosing obesity and predicting cardiometabolic risk in Mexican adolescents / Análisis comparativo de indicadores antropométricos para el diagnóstico de obesidad y predicción del riesgo cardiometabólico en adolescentes mexicanos

Introduction: obesity is a cardiometabolic risk (CMR) factor in adolescents. It represents a public health problem that requires simple diagnostic strategies based on the determination of anthropometric indicators (AIs) such as body mass index (BMI), waist circumference (WC), conicity index (CONI), waist-to-height ratio (WHtR), and body fat percentage (BFP). The purpose of the current contribution was to analyze the utility of the aforementioned AIs for evaluating obesity as a CMR factor in Mexican adolescents. Materials and methods: the design of the study is descriptive and cross-sectional. Nutritional status was established by using various AIs and as a CMR factor under the criteria of WHtR. Participating in the present investigation were 2,000 adolescents from 15 to 17 years of age, of which 1,079 (53.9 %) were female and 921 (46.1 %) were male. All were high school students in Tuxtla Gutiérrez, Chiapas, Mexico. Results and conclusion: the prevalence of obesity was influenced by gender. With the WHtR and BFP, male students exhibited a greater prevalence of obesity, while with the BMI and CONI, the percentage of obesity was similar between the two genders. BMI was significantly correlated with BFP, WC and WHtR, and was one of the AIs with the greatest area under the curve, showing a good capacity to predict cardiometabolic risk. BMI is a simple and adequate tool for diagnosing obesity and predicting CMR in adolescents (AU)

Introducción: la obesidad es un factor de riesgo cardiometabolico (RCM) en los adolescentes y representa un problema de salud pública que requiere estrategias diagnosticas sencillas, basadas en la determinación de indicadores antropométricos (IA) como el índice de masa corporal (IMC), la circunferencia de la cintura (CC), el índice de conicidad (ICONI), el índice de cintura-talla (ICT) y el porcentaje de grasa corporal (PGC). El propósito del presente estudio fue analizar la utilidad de diversos IA (IMC, CC, ICONI, ICT y PGC) para evaluar la obesidad como factor de RCM en adolescentes mexicanos. Materiales y métodos: el diseño del estudio fue descriptivo y transversal. Se analizó el estado nutricional mediante varios IA y el factor de RCM bajo los criterios del ICT. Este estudio fue conducido en 2000 adolescentes de entre 15 y 17 años, de los cuales 1079 (53,9 %) eran mujeres y 921 (46,1 %) varones, todos ellos estudiantes de nivel medio superior de Tuxtla Gutiérrez, Chiapas, México. Resultados y conclusión: la prevalencia de la obesidad estuvo influenciada por el género: los varones presentaron una mayor prevalencia de obesidad con ICT y PGC, mientras que con IMC e ICONI, el porcentaje de obesidad fue similar entre ambos géneros. El IMC se correlacionó significativamente con el PGC, la CC y el ICT, y fue uno de los IA con mayor área bajo la curva, mostrando una buena capacidad para predecir el RCM. El IMC representa una herramienta sencilla y adecuada para el diagnóstico de obesidad y predecir el RCM en adolescentes (AU)

Ovariectomy increases the age-induced hyperphosphorylation of Tau at hippocampal CA1.

One of the main hallmarks of Alzheimer's disease includes the neurofibrillary tangles formation produced by hyperphosphorylation of the Tau protein, whose expression is putatively regulated by the ovarian hormones estradiol and progesterone. Hippocampus is a brain region that participates in many functions related to learning and memory; in addition, it is abundant in both estradiol and progesterone receptors. In this study, we explore the expression of Tau hyperphosphorylation at hippocampus and the performance of rats in an autoshaping learning task at 5, 10 and 15 months after the ovaries removal. In these animals, ovariectomy was performed at 3 months of age. These data were compared with those derived from intact rats at 8, 13 and 18 months old. A clear decrease in the number of conditioned responses of both intact and ovariectomized rats in the autoshaping learning task was observed. The interaction of both factors confirms that, in this test, learning varies depending on aging and the presence or absence of ovaries. A progressive increase in hippocampal Tau phosphorylation at Ser-396 was observed in either intact or ovariectomized rats. Interestingly, an interaction between the analyzed factors shows that such hyperphosphorylation was potentiated by the absence of ovaries. These results emphasize the importance of aging and the lack of ovarian hormones for an associative learning test and for the expression of one of the most important hallmarks of Alzheimer's disease.

An enriched environment and 17-beta estradiol produce similar pro-cognitive effects on ovariectomized rats.

Estrogen depletion due to aging, surgery or pathological events can cause a multitude of problems, including neurodegenerative alterations. In rodents without ovaries, 17-beta estradiol (E2) has been shown to produce beneficial effects on cognition, stimulating brain regions (e.g., the neocortex, hippocampus and amygdala) related to cognition and learning. Another treatment that stimulates these brain regions is an enriched environment (EE), which is a complex set of external factors in the immediate surroundings that facilitates greater stimulation of sensorial, cognitive and motor circuits of the brain. The aim of the present study was to test, using an animal model of ovariectomy-induced impairment of memory, the relative effect of E2 (with a time-released pellet; 1 µg/rat/day), EE exposure and a combination of both treatments. Experimental and control groups were submitted to two memory tests 18 weeks post-surgery: the autoshaping learning task (ALT) for measuring associative learning and the novel object recognition test (NORT) for evaluating short- and long-term memory. To assess potential motor impairments caused by treatments, all rats were tested after the ALT in an automatic activity counter. Results from ALT show that the ovariectomy blocked the conditioned responses displayed, an effect rescued by chronic treatment with estrogen or EE exposure. The combination of both treatments did not improve the results obtained separately. In the NORT, the exploration time for recognizing a novel object was similar in the short run with all groups, but greater in the long run with hormone administration or EE exposure. As with the ALT, in the NORT there was no improvement shown by the combination treatment. These data were not masked by changes in spontaneous activity because this parameter was not modified in the rats by either treatment. Possible action mechanisms are proposed, taking into account the role of corticosterone and BDNF on cognition.

Role of estrogens on some cognition-related aspects.

Two of the most studied brain areas related with learning and memory are prefrontal cortex and hippocampus. However, serious inconsistencies arise when these regions are analyzed in relation to the role of estrogens on cognitive deterioration. Some of these contradictions are reviewed in the context of the recently proposed critical period hypothesis, which takes into account the frame-time after cessation of ovarian function. Other factors related with cognition and influenced by estrogens include their role on; a) cholinergic central transmission, b) spinogenesis and synaptogenesis at hippocampus, and c) classical genomic and rapid non genomic effects. Understanding the cellular and molecular basis of these phenomena is vital for designing novel therapeutic actions applicable to human health and disease.

Effect of a M1 allosteric modulator on scopolamine-induced amnesia.

It is well accepted that acetylcholine is involved in memory and learning processes and that loss of memory is characteristic of Alzheimer's disease (AD). Several muscarinic agonists have been shown to be clinically effective in the treatment of AD. However, their use has been limited due to adverse side effects. As a result, more selective M1 agonists are expected to be the next generation of agents for the treatment of AD. One pharmacological approach to evaluate possible cognitive effects of compounds includes their ability to reverse scopolamine-induced amnesia. In the current study the succinamide and succinimide of p-aminophenol, two newly synthesized compounds that were previously designed to be acetylcholine analogues, were evaluated in a Pavlovian/Instrumental autoshaped memory task. Simultaneously, docking studies on the M1 receptor were done. The scopolamine-induced amnesia was reversed by the amide but not the imide. These findings are in line with results derived from the docking simulations, and suggest that at least the succinamide of p-aminophenol could represent a novel candidate for the treatment of AD.

Effects of succinic acid derivatives on ex vivo acetylcholinesterase activity.

In the present study the acetylcholinesterase (AChE) inhibition and acute toxicity of two succinic acid derivatives were compared with tacrine. Administration of a single dose of each of two succinic acid derivatives produced a time and dose-dependent inhibition of brain AChE activity. Although the magnitude of the cholinergic effects observed with the two succinic acid derivatives was similar to that seen with tacrine and other AChE inhibitors, the toxicity study showed that the new inhibitors have less adverse side effects.