Changes in food intake, metabolic parameters and insulin resistance are induced by an isoenergetic, medium-chain fatty acid diet and are associated with modifications in insulin signalling in isolated rat pancreatic islets

LLong-chain fatty acids are capable of inducing alterations in the homoeostasis of glucose-stimulated insulin secretion (GSIS), but the effect of medium-chain fatty acids (MCFA) is poorly elucidated. In the present study, we fed a normoenergetic MCFA diet to male rats from the age of 1 month to the age of 4 months in order to analyse the effect of MCFA on body growth, insulin sensitivity and GSIS. The 45% MCFA substitution of whole fatty acids in the normoenergetic diet impaired whole body growth and resulted in increased body adiposity and hyperinsulinaemia, and reduced insulin-mediated glucose uptake in skeletal muscle. In addition, the isolated pancreatic islets from the MCFA-fed rats showed impaired GSIS and reduced protein kinase Ba (AKT1) protein expression and extracellular signal-related kinase isoforms 1 and 2 (ERK(1/2)) phosphorylation, which were accompanied by increased cellular death. Furthermore, there was a mildly increased cholinergic sensitivity to GSIS. We discuss these findings in further detail, and advocate that they might have a role in the mechanistic pathway leading to the compensatory hyperinsulinaemic status found in this animal model.

Oral leucine supplementation is sensed by the brain but neither reduces food intake nor induces an anorectic pattern of gene expression in the hypothalamus

Leucine activates the intracellular mammalian target of the rapamycin (mTOR) pathway, and hypothalamic mTOR signaling regulates food intake. Although central infusion of leucine reduces food intake, it is still uncertain whether oral leucine supplementation is able to affect the hypothalamic circuits that control energy balance. We observed increased phosphorylation of p70s6k in the mouse hypothalamus after an acute oral gavage of leucine. We then assessed whether acute oral gavage of leucine induces the activation of neurons in several hypothalamic nuclei and in the brainstem. Leucine did not induce the expression of Fos in hypothalamic nuclei, but it increased the number of Fos-immunoreactive neurons in the area postrema. In addition, oral gavage of leucine acutely increased the 24 h food intake of mice. Nonetheless, chronic leucine supplementation in the drinking water did not change the food intake and the weight gain of ob/ob mice and of wild-type mice consuming a low- or a high-fat diet. We assessed the hypothalamic gene expression and observed that leucine supplementation increased the expression of enzymes (BCAT1, BCAT2 and BCKDK) that metabolize branched-chain amino acids. Despite these effects, leucine supplementation did not induce an anorectic pattern of gene expression in the hypothalamus. In conclusion, our data show that the brain is able to sense oral leucine intake. However, the food intake is not modified by chronic oral leucine supplementation. These results question the possible efficacy of leucine supplementation as an appetite suppressant to treat obesity

Dietary intake of environmentally persistent plaguicides in the european population

[EN] Global pollution has become one of the most important problems of the modern societies and pesticides play a major role among the chemical contaminants that are released to the environment every year. Organochlorine compounds have been widely used in the past all over the world as pesticides and some of them are still used for the control of vectors of infectious diseases. Due to their high lipophilicity, stability and resistance to degradation, most of them have been banned or strictly regulated but their levels remain high in the environment as persistent organic pollutants (POPs). Their presence in the environment leads to their introduction into the food chain, especially affecting food of animal origin with higher fat content. Due to their liposolubility, these substances tend to be bioaccumulated into the fat tissues of living beings along their entire lives, and to be biomagnificated across trophic levels in the food chain. Thus, the main human source of these pesticides comes from the daily intake of contaminated food from environmental sources. It has been established the role of many of the POPs as endocrine disruptors and even as carcinogenic agents, being thus considered as important risk factors for health. Moreover, chronic exposure to pesticides, even at very low levels, has been related with cancer, fertility problems, immunosuppression and other diseases. For this reason, it is important to know the level of POPs contamination and to identify the main sources contributing to it. Fish, meat and dairy products are the food groups with the highest levels of pollution. However, the residue levels vary by geographic area, and are influenced by several factors as food security policies, local pesticide use patterns, environmental practices, or the time when the study is conducted. Food habits, conditioned by different social and economic factors, as well as several biological factors (i.e. gender, sex and age), determine the levels of POPs exposure in the population. The purpose of this chapter is to give an overview of the dietary intake of environmentally persistent pesticides by the European population, and the potential adverse consequences of this exposure on human health.

Plant food supplement (PFS) market structure in EC Member States, methods and techniques for the assessment of individual PFS intake

The popularity of herbal products, especially plant food supplements (PFS) and herbal medicine is on the rise in Europe and other parts of the world, with increased use in the general population as well as among specific subgroups encompassing children, women or those suffering from diseases such as cancer. The aim of this paper is to examine the PFS market structures in European Community (EC) Member States as well as to examine issues addressing methodologies and consumption data relating to PFS use in Europe. A revision of recent reports on market data, trends and main distribution channels, in addition an example of the consumption of PFS in Spain, is presented. An overview of the methods and administration techniques used...

Nocturnal dipping behaviour in normotensive white children and young adults in response to changes in salt intake

Nocturnal nondipping is a feature of salt-sensitive, hypertensive individuals. In normotensive children and adults, the impact of salt intake on circadian blood pressure (BP) rhythm is not well defined.

Confirmation analysis of ethyl glucuronide and ethyl sulfate in human serum and urine by CZE-ESI-MS(n) after intake of alcoholic beverages

CZE coupled to sheath liquid-based electrospray ionization (ESI) and multiple-stage ion trap mass spectrometry (MS(n) ) was used for the confirmation analysis of ethyl glucuronide (EtG) and ethyl sulfate (EtS) in human serum and urine collected after intake of alcoholic beverages. Electrophoretic separations were performed in uncoated fused-silica capillaries using a pH 9.5 ammonium acetate background electrolyte and normal polarity. MS detection of EtG and EtS occurred after negative ionization using a spray liquid containing 0.5% v/v ammonia in isopropanol/water (60:40%, v/v). CZE-MS and CZE-MS² results obtained after injection of solid-phase extracts for EtG and EtS and of diluted urine confirmed the presence of EtG and EtS in samples whose levels were previously determined by CZE with indirect UV detection. Detection limits of each compound were estimated to be around 2.0 (injection of diluted urine) and 0.2 μg/mL (extracts).

High salt intake down-regulates colonic mineralocorticoid receptors, epithelial sodium channels and 11β-hydroxysteroid dehydrogenase type 2

Besides the kidneys, the gastrointestinal tract is the principal organ responsible for sodium homeostasis. For sodium transport across the cell membranes the epithelial sodium channel (ENaC) is of pivotal relevance. The ENaC is mainly regulated by mineralocorticoid receptor mediated actions. The MR activation by endogenous 11β-hydroxy-glucocorticoids is modulated by the 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). Here we present evidence for intestinal segment specific 11β-HSD2 expression and hypothesize that a high salt intake and/or uninephrectomy (UNX) affects colonic 11β-HSD2, MR and ENaC expression. The 11β-HSD2 activity was measured by means of 3H-corticosterone conversion into 3H-11-dehydrocorticosterone in Sprague Dawley rats on a normal and high salt diet. The activity increased steadily from the ileum to the distal colon by a factor of about 3, an observation in line with the relevance of the distal colon for sodium handling. High salt intake diminished mRNA and protein of 11β-HSD2 by about 50% (p<0.001) and reduced the expression of the MR (p<0.01). The functionally relevant ENaC-β and ENaC-γ expression, a measure of mineralocorticoid action, diminished by more than 50% by high salt intake (p<0.001). The observed changes were present in rats with and without UNX. Thus, colonic epithelial cells appear to contribute to the protective armamentarium of the mammalian body against salt overload, a mechanism not modulated by UNX.

The meanings of pasture in resource degradation negotiations: Evidence from post-socialist rural Kyrgyzstan

Pasture use in the Kyrgyz Republic has changed significantly as a result of fundamental political, economic, and societal changes following the collapse of the Soviet Union and the subsequent changes in people’s livelihoods. Government institutions criticize current land use patterns as unsustainable and the cause of degradation. But at the local level, pasture quality is rarely seen as a major problem. This article uses a qualitative approach to examine the tension between these views and addresses current land use practices and related narratives about pasture degradation in rural Kyrgyzstan. By focusing on meanings ascribed to pastures, it shows how people closely relate current practices to the experiences and value systems of the Soviet period and to changing identities emerging in the post-Soviet transformation process. It argues that proper understanding of resource degradation issues requires adequate consideration of the context of meaning constructed by local resource users when they make sense of their environment.

Equine botulism and acute pasture myodystrophy: new soil-borne emerging diseases in Switzerland?

In Switzerland, the incidence of equine botulism and acute pasture myodystrophy have remarkably increased in the last five years. Equine fodder-borne botulism in Europe is most likely caused by Clostridium botulinum types C and D that produce the toxins BoNT/C and BoNT/D. Horses showing signs suggestive of botulism (muscle weakness and tremors, reduced tongue tone, slow chewing, salivation and difficulties swallowing, drooping eyelids, mydriasis), especially patients that have fed on suspect fodder (mostly haylage), must be treated with anti-serum as soon as possible.They also need intensive care, which is often difficult to provide and always expensive in the face of a guarded to poor prognosis. Therefore, prevention (high standards of forage quality and vaccination) is all the more important. Pasture myodystrophy is an acute disease with signs of rhabdomyolysis and lethality rate over 90%. It affects grazing horses under frosty, windy and rainy conditions. Preliminary results indicate that Clostridium sordellii and Clostridium bifermentans producing lethal toxin may play a role in pasture myodystrophy. Our efforts concentrate on developing a new subunit vaccine for equine botulism and understanding the ethiology and pathogenesis of pasture myodystrophy with the goal of improving prevention against these highly fatal diseases that present a significant risk to our horse population.

The effect of increased lipid intake on hormonal responses during aerobic exercise in endurance-trained men

In view of the growing health problem associated with obesity, clarification of the regulation of energy homeostasis is important. Peripheral signals, such as ghrelin and leptin, have been shown to influence energy homeostasis. Nutrients and physical exercise, in turn, influence hormone levels. Data on the hormonal response to physical exercise (standardized negative energy balance) after high-fat (HF) or low-fat (LF) diet with identical carbohydrate intake are currently not available. The aim of the study was to investigate whether a short-term dietary intervention with HF and LF affects ghrelin and leptin levels and their modulators, GH, insulin and cortisol, before and during aerobic exercise. Eleven healthy, endurance-trained male athletes (W(max) 365 +/- 29 W) were investigated twice in a randomized crossover design following two types of diet: 1. LF - 0.5 g fat/kg body weight (BW) per day for 2.5 days; 2. HF - 0.5 g fat/kg BW per day for 1 day followed by 3.5 g fat/kg BW per day for 1.5 days. After a standardized carbohydrate snack in the morning, metabolites and hormones (GH, ghrelin, leptin, insulin and cortisol) were measured before and at regular intervals throughout a 3-h aerobic exercise test on a cycloergometer at 50% of W(max). Diet did not significantly affect GH and cortisol concentrations during exercise but resulted in a significant increase in ghrelin and decrease in leptin concentrations after LF compared with HF diet (area under the curve (AUC) ghrelin LF vs HF: P < 0.03; AUC leptin LF vs HF: P < 0.02, Wilcoxon rank test). These data suggest that acute negative energy balance induced by exercise elicits a hormonal response with opposite changes of ghrelin and leptin. In addition, the hormonal response is modulated by the preceding intake of fat.

Psychobiological responses to drug cues before and after methadone intake in heroin-dependent patients: A pilot study

Craving and stress frequently drive compulsive heroin use. Although methadone attenuates craving, drug-conditioned stimuli can trigger craving and possibly stress arousal in heroin-dependent patients receiving methadone maintenance. This study investigated drug cue-related craving, affectivity, and cortisol reactivity in 16 methadone-maintained patients before and after daily methadone. Unexpectedly, drug cues significantly increased craving after (t[15]=-4.27, p=0.001), but not before methadone intake. Patients displayed blunted cortisol response after post-methadone drug cues (t[15]=3.05, p=0.008) suggesting dissociated craving and cortisol reactivity after methadone intake of possible clinical relevance.

Postexercise fat intake repletes intramyocellular lipids but no faster in trained than in sedentary subjects

The hypotheses that postexercise replenishment of intramyocellular lipids (IMCL) is enhanced by endurance training and that it depends on fat intake were tested. Trained and untrained subjects exercised on a treadmill for 2 h at 50% peak oxygen consumption, reducing IMCL by 26-22%. During recovery, they were fed 55% (high fat) or 15% (low fat) lipid energy diets. Muscle substrate stores were estimated by (1)H (IMCL)- and (13)C (glycogen)-magnetic resonance spectroscopy in tibialis anterior muscle before and after exercise. Resting IMCL content was 71% higher in trained than untrained subjects and correlated significantly with glycogen content. Both correlated positively with indexes of insulin sensitivity. After 30 h on the high-fat diet, IMCL concentration was 30-45% higher than preexercise, whereas it remained 5-17% lower on the low-fat diet. Training status had no significant influence on IMCL replenishment. Glycogen was restored within a day with both diets. We conclude that fat intake postexercise strongly promotes IMCL repletion independently of training status. Furthermore, replenishment of IMCL can be completed within a day when fat intake is sufficient.

Urinary iodine concentration during pregnancy in an area of unstable dietary iodine intake in Switzerland

We prospectively investigated urinary iodine concentration (UIC) in pregnant women and in female, non-pregnant controls in the canton of Berne, Switzerland, in 1992. Mean UIC of pregnant women [205 +/- 151 microg iodine/g creatinine (microg l/g Cr); no. = 153] steadily decreased from the first (236 +/- 180 microg l/g Cr; no. = 31) to the third trimester (183 +/- 111 microg l/g Cr, p < 0.0001; no. = 66) and differed significantly from that of the control group (91 +/- 37 microg l/g Cr, p < 0.0001; no. = 119). UIC increased 2.6-fold from levels indicating mild iodine deficiency in controls to the first trimester, demonstrating that high UIC during early gestation does not necessarily reflect a sufficient iodine supply to the overall population. Pregnancy is accompanied by important alterations in the regulation of thyroid function and iodine metabolism. Increased renal iodine clearance during pregnancy may explain increased UIC during early gestation, whereas increased thyroidal iodine clearance as well as the iodine shift from the maternal circulation to the growing fetal-placental unit, which both tend to lower the circulating serum levels of inorganic iodide, probably are the causes of the continuous decrease of UIC over the course of pregnancy. Mean UIC in our control group, as well as in one parallel and several consecutive investigations in the same region in the 1990s, was found to be below the actually recommended threshold, indicating a new tendency towards mild to moderate iodine deficiency. As salt is the main source of dietary iodine in Switzerland, its iodine concentration was therefore increased nationwide in 1998 for the fourth time, following increases in 1922, 1965 and 1980.