Sexually dimorphic role of G protein-coupled estrogen receptor (GPER) in modulating energy homeostasis.

This article is part of a Special Issue "Energy Balance". The classical estrogen receptors, estrogen receptor-α and estrogen receptor-ß are well established in the regulation of body weight and energy homeostasis in both male and female mice, whereas, the role for G protein-coupled estrogen receptor 1 (GPER) as a modulator of energy homeostasis remains controversial. This study sought to determine whether gene deletion of GPER (GPER KO) alters body weight, body adiposity, food intake, and energy homeostasis in both males and females. Male mice lacking GPER developed moderate obesity and larger adipocyte size beginning at 8 weeks of age, with significant reductions in energy expenditure, but not food intake or adipocyte number. Female GPER KO mice developed increased body weight relative to WT females a full 6 weeks later than the male GPER KO mice. Female GPER KO mice also had reductions in energy expenditure, but no significant increases in body fat content. Consistent with their decrease in energy expenditure, GPER KO males and females showed significant reductions in two brown fat thermogenic proteins. GPER KO females, prior to their divergence in body weight, were less sensitive than WT females to the feeding-inhibitory effects of leptin and CCK. Additionally, body weight was not as modulated by ovariectomy or estradiol replacement in GPER KO mice. Estradiol treatment activated phosphorylated extracellular signal-regulated kinase (pERK) in WT but not GPER KO females. For the first time, GPER expression was found in the adipocyte but not the stromal fraction of adipose tissue. Together, these results provide new information elucidating a sexual dimorphism in GPER function in the development of postpubertal energy balance.

Effects of maternal genotype and diet on offspring glucose and fatty acid-sensing ventromedial hypothalamic nucleus neurons.

Maternal obesity accentuates offspring obesity in dams bred to develop diet-induced obesity (DIO) on a 31% fat, high-sucrose, high-energy (HE) diet but has no effect on offspring of diet-resistant (DR) dams. Also, only DIO dams become obese when they and DR dams are fed HE diet throughout gestation and lactation. We assessed glucose and oleic acid (OA) sensitivity of dissociated ventromedial hypothalamic nucleus (VMN) neurons from 3- to 4-wk old offspring of DIO and DR dams fed chow or HE diet using fura-2 calcium imaging to monitor intracellular calcium fluctuations as an index of neuronal activity. Offspring of DIO dams fed chow had approximately 2-fold more glucose-inhibited (GI) neurons than did DR offspring. This difference was eliminated in offspring of DIO dams fed HE diet. At 2.5 mM glucose, offspring of chow-fed DIO dams had more GI neurons that were either excited or inhibited by OA than did DR offspring. Maternal HE diet intake generally increased the percentage of neurons that were excited and decreased the percentage that were inhibited by OA in both DIO and DR offspring. However, this effect was more pronounced in DIO offspring. These data, as well as concentration-dependent differences in OA sensitivity, suggest that genotype, maternal obesity, and dietary content can all affect the sensitivity of offspring VMN neurons to glucose and long-chain fatty acids. Such altered sensitivities may underlie the propensity of DIO offspring to become obese when fed high-fat, high-sucrose diets.

Characteristics and mechanisms of hypothalamic neuronal fatty acid sensing.

We assessed the mechanisms by which specialized hypothalamic ventromedial nucleus (VMN) neurons utilize both glucose and long-chain fatty acids as signaling molecules to alter their activity as a potential means of regulating energy homeostasis. Fura-2 calcium (Ca(2+)) and membrane potential dye imaging, together with pharmacological agents, were used to assess the mechanisms by which oleic acid (OA) alters the activity of dissociated VMN neurons from 3- to 4-wk-old rats. OA excited up to 43% and inhibited up to 29% of all VMN neurons independently of glucose concentrations. In those neurons excited by both 2.5 mM glucose and OA, OA had a concentration-dependent effective excitatory concentration (EC(50)) of 13.1 nM. Neurons inhibited by both 2.5 mM glucose and OA had an effective inhibitory concentration (IC(50)) of 93 nM. At 0.5 mM glucose, OA had markedly different effects on these same neurons. Inhibition of carnitine palmitoyltransferase, reactive oxygen species formation, long-chain acetyl-CoA synthetase and ATP-sensitive K(+) channel activity or activation of uncoupling protein 2 (UCP2) accounted for only approximately 20% of OA's excitatory effects and approximately 40% of its inhibitory effects. Inhibition of CD36, a fatty acid transporter that can alter cell function independently of intracellular fatty acid metabolism, reduced the effects of OA by up to 45%. Thus OA affects VMN neuronal activity through multiple pathways. In glucosensing neurons, its effects are glucose dependent. This glucose-OA interaction provides a potential mechanism whereby such "metabolic sensing" neurons can respond to differences in the metabolic states associated with fasting and feeding.

Effects of leptin on rat ventromedial hypothalamic neurons.

Neurons in the ventromedial and arcuate hypothalamic nuclei (VMN and ARC, respectively) mediate many of leptin's effects on energy homeostasis. Some are also glucosensing, whereby they use glucose as a signaling molecule to regulate their firing rate. We used fura-2 calcium (Ca2+) imaging to determine the interactions between these two important mediators of peripheral metabolism on individual VMN neurons and the mechanisms by which leptin regulates neuronal activity in vitro. Leptin excited 24%, inhibited 20%, and had a biphasic response in 10% of VMN neurons. Excitation occurred with a EC50 of 5.2 fmol/liter and inhibition with a IC50 of 4.2 fmol/liter. These effects were independent of the ambient glucose levels, and both glucosensing and non-glucosensing neurons were affected by leptin. In contrast, the ARC showed a very different distribution of leptin-responsive neurons, with 40% leptin excited, 10% leptin inhibited, and 2% having a biphasic response (chi2=60.2; P<0.0001). Using pharmacological manipulations we found that leptin inhibits VMN neurons via activation of phosphoinositol-3 kinase and activation of the ATP-sensitive K+ channel. In addition, leptin inhibition was antagonized by 5'-AMP-activated protein kinase activation in 39% of neurons but was unaffected by 5'-AMP-activated protein kinase inhibition. No mechanism was delineated for leptin-induced excitation. Thus, within the physiological range of brain glucose levels, leptin has a differential effect on VMN vs. ARC neurons, and acts on both glucosensing and non-glucosensing VMN neurons in a glucose-independent fashion with inhibition primarily dependent upon activation of the ATP-sensitive K+ channel.

Altered hypothalamic leptin, insulin, and melanocortin binding associated with moderate-fat diet and predisposition to obesity.

Rats with a genetic predisposition to develop diet-induced obesity (DIO) have a preexisting reduction in central leptin and insulin sensitivity. High-fat diets also reduce sensitivity to leptin, insulin, and melanocortin agonists. We postulated that such reduced sensitivities would be associated with decreased binding to the hypothalamic leptin, insulin, and melanocortin receptors in selectively bred DIO rats and in rats fed a high-energy (HE; 31% fat) diet for 7 wk. On HE diet, DIO rats gained 15% more weight and had 121% heavier fat pads and 70% higher leptin levels than low fat chow-fed DIO rats. Diet-resistant (DR) rats gained no more weight on HE diet but had 48% heavier fat pads and 70% higher leptin levels than chow-fed DR rats. Compared with DR rats, DIO (125)I-leptin binding was 41, 36, and 40% lower in the hypothalamic dorsomedial, arcuate, and dorsomedial portion of the ventromedial nuclei, respectively, and arcuate (125)I-insulin binding was 31% lower independent of diet. In contrast, hypothalamic melanocortin binding did not differ between DIO and DR rats. However, HE diet intake lowered lateral hypothalamic melanocortin-3 and melanocortin-4 receptor and hippocampal insulin binding of both DIO and DR rats and hypothalamic paraventricular nucleus melanocortin-4 receptor binding only in DR rats. Neither genotype nor diet affected substantia nigra or ventral tegmental area binding. These results corroborate our previous findings demonstrating a preexisting decrease in DIO hypothalamic leptin and insulin signaling and demonstrate that HE diet intake reduces hypothalamic melanocortin and hippocampal insulin binding.

Feeding effects of melanocortin ligands--a historical perspective.

The process of energy homeostasis is a highly regulated process involving interacting signals between a variety of anorexigenic and orexigenic peptides, proteins and signaling molecules. The melanocortin system is an important component of this complex regulatory network. Involvement of the melanocortin pathway in the control of food intake and body weight regulation has been studied extensively in the past two decades. Previous studies that involve central administration of melanocortin molecules and examination of molecules that effect food intake in melanocortin knockout (KO) mice (MC3R, MC4R, POMC, AGRP and NPY) have been examined. In this review, we have summarized feeding studies that have resulted in the recognition of the melanocortin system as a major contributor to the complex neuroendocrine system regulating energy homeostasis.

Ghrelin-induced food intake and growth hormone secretion are altered in melanocortin 3 and 4 receptor knockout mice.

Ghrelin stimulates food intake in part by activating hypothalamic neuropeptide Y (NPY) neurons/agouti related peptide (AGRP) neurons. We investigated the role of AGRP/melanocortin signaling in ghrelin-induced food intake by studying melanocortin 3 and 4 receptor knockout (MC3R KO and MC4R KO) mice. We also determined whether reduced ghrelin levels and/or an altered sensitivity to the GH-stimulating effects of ghrelin accompany the obesity syndromes of MC3R KO and MC4R KO mice. Compared to wild-type (WT) mice, the effects of ghrelin on food intake were reduced in MC3R KO and MC4R KO mice and circulating ghrelin levels were reduced in female MC4R KO mice. Female MC3R KO and MC4R KO mice exhibited a diminished responsiveness to the GH-releasing effects of ghrelin. Thus, deletion of the MC3R or MC4R results in a decreased sensitivity to ghrelin and verifies the involvement in the melanocortin system in ghrelin-induced food intake.

New developments in high pressure x-ray spectroscopy beamline at High Pressure Collaborative Access Team.

The 16 ID-D (Insertion Device - D station) beamline of the High Pressure Collaborative Access Team at the Advanced Photon Source is dedicated to high pressure research using X-ray spectroscopy techniques typically integrated with diamond anvil cells. The beamline provides X-rays of 4.5-37 keV, and current available techniques include X-ray emission spectroscopy, inelastic X-ray scattering, and nuclear resonant scattering. The recent developments include a canted undulator upgrade, 17-element analyzer array for inelastic X-ray scattering, and an emission spectrometer using a polycapillary half-lens. Recent development projects and future prospects are also discussed.

Progress in the development of melanocortin receptor selective ligands.

The melanocortin pathway consists of endogenous agonists, antagonists, G-protein coupled receptors (GPCRs), and auxiliary proteins. This pathway has been identified to participate physiologically in numerous biological pathways including energy homeostasis, pigmentation, sexual function, inflammation, cardiovascular function, adrenal function, sebaceous gland lipid production, just to list a few. During this past decade, a clear link between the melanocortin-4 receptor (MC4R) and obesity, in both mice and humans via the regulation of food intake and energy homeostasis, has made this pathway the target of many academic and industrial research endeavors in attempts to develop potent and selective MC4R small molecules as anti-obesity therapeutic agents. Herein, we attempt to summarize the known proteins that constitute the melanocortin system and discuss advances in peptide and non-peptide drug discovery.

Adverse reactions to nitrofurantoin. Analysis of 921 reports.

Reports on adverse reactions to nitrofurantoin today are common in Sweden and constitute 10 to 12 percent of all incoming reports. We present an analysis of 921 reports of adverse reactions received by the Swedish Adverse Drug Reaction Committee during the period 1966--1976. The two largest groups consist of reports of acute pulmonary reactions (43 percent) and allergic reactions (42 percent). The remaining reports fall into any of four smaller groups, chronic pulmonary reactions, liver damage, blood dyscrasias or neuropathy. Acute pulmonary and acute allergic reactions in all aspects are very similar and carry the characteristics of an acute hypersensitivity reaction. The increasing number of reports--even in relation to sales figures--would be best explained by a continuous sensitization. Chronic pulmonary reactions (interstitial pneumonitis) afflict older patients, often after prolonged treatment with relatively small doses. We suggest that these reactions are elicited by a toxic mechanism. Seventy-one percent of all reactions were severe enough to cause the patient's hospitalization; only 1 percent was fatal. The risk of an adverse reaction varies with sex and age, increases with age and is higher in women than in men. The time has come for a re-evaluation of nitrofurantoin and its role in the treatment of urinary tract infections.

Insomnia in men-a 10-year prospective population based study.

STUDY OBJECTIVES: to prospectively analyze changes in the prevalence of insomnia and the relationship between insomnia, aging, lifestyle, and medical disorders DESIGN: a longitudinal population survey. PARTICIPANTS: a randomly selected population sample of 2,602 men (age 30-69 years) from Uppsala in Sweden. INTERVENTION: all participants answered a questionnaire on sleep disturbances, lifestyle factors, and medical disorders in 1984 and again in 1994. MEASUREMENTS AND RESULTS: The prevalence of INSOMNIA was 10.3% in 1984 and 12.8% in 1994. No significant correlation was found between age and insomnia in any of the two time periods. Insomnia in 1994 was independently related to having insomnia in 1984 (OR=6.45), being over-weight (BMI> 27 kg/m2) (OR=1.35), physical inactivity (OR=1.42), alcohol dependence (OR=1.75), psychiatric disorders (OR=8.27) and joint/low back disorders (OR=2.95). The number of subject with reported insomnia in 1984 but not 1994 was 149. Subjects that quit smoking during the time period had an increased likeliness of remission (OR=2.70) while men who were overweight were less likely to remit (OR=0.43). CONCLUSIONS: We conclude that in men insomnia is related to lifestyle factors such as obesity, physical inactivity and alcohol dependency but not to aging. Medical disorders such as joint and low back disorders and psychiatric illnesses also increase the risk of reporting insomnia. This study demonstrates the close relationship between quality of sleep and overall health status.

Sleep disturbances in a young adult population: can gender differences be explained by differences in psychological status?

To study the prevalence of reported sleep disturbances and the association between these complaints and psychological status, 529 randomly selected subjects aged 20-45 years were questioned about their sleep symptoms and psychological status by means of questionnaires. In this young population, feeling refreshed in the morning almost every day was reported by only 15.3%. Females reported a significantly longer mean total sleep time (TST) than males (F: 425 +/- 58 minutes, M: 403 +/- 50 minutes; p < 0.01). Despite this, the difference compared with the reported need of sleep was greater in females (56 +/- 62 minutes) than in males (40 +/- 51 minutes) (p < 0.05). Difficulties maintaining sleep (DMS, > or = 3/week) (F: 20.1%, M: 10.4%; p < 0.01), the absence of feeling refreshed in the morning (F: 36.2%, M: 26.8%; p < 0.05), and excessive daytime sleepiness (EDS) (F: 23.3%, M: 15.9%; p < 0.05) were significantly more common among females. According to the Hospital Anxiety and Depression scale, females suffered from anxiety more frequently than males (F: 32.8%, M: 18.9%; p < 0.001). An association was found between anxiety and many sleep disturbances. After making adjustments for age, smoking, snoring, gender and psychological status by means of multiple regression, the gender differences mentioned above remained significant. We conclude that despite a longer TST, females report insufficient sleep, EDS, DMS, and the absence of feeling refreshed in the morning more frequently than males. The higher prevalence of anxiety among females alone cannot explain the gender differences in sleep disturbances seen in this population.

Prevalence of sleep disturbances among young adults in three European countries.

The aim of this investigation was to study the geographic variation in sleep complaints and to identify risk factors for sleep disturbances in three European countries: Iceland (Reykjavik), Sweden (Uppsala and Göteborg) and Belgium (Antwerp). The study involved a random population of 2,202 subjects (age 20-45 years) who participated in the European Community Respiratory Health Survey. The subjects answered a questionnaire on sleep disturbances. Participants in Iceland and Sweden also estimated their sleep habits and sleep times during a period of 1 week in a sleep diary. Habitual (> or = 3/week) difficulties inducing sleep (DIS) were reported by 6-9% and early morning awakenings by 5-6% of the subjects. The estimated number of awakenings and the prevalence of nightmares was significantly lower in Reykjavik. Participants in Reykjavik went to bed at night and woke in the morning approximately 1 hour later than participants at the Swedish centers (p < 0.001). Symptoms of gastroesophageal reflux (GER) were associated with DIS (odds ratio [OR] = 2.7), nightmares (OR = 4.4), longer sleep latency and frequent nocturnal awakenings. Smoking correlated positively to DIS (OR = 1.8) and estimated sleep latency. We conclude that the prevalence of DIS was fairly similar at these four European centers but that there was a variation in the prevalence of nightmares and nocturnal awakenings. The significant correlation between reported GER and subjective quality of sleep should be followed up in studies using objective measurements.

Prevalence of sleep apnea syndrome among Swedish men--an epidemiological study.

The prevalence of the sleep apnea syndrome (SAS) among Swedish men 30-69 years old was estimated by a two-stage procedure. In the first stage, 4064 questionnaires were mailed to a random sample of a defined population in the municipality of Uppsala. The response rate was almost 80%; 15.6% of the responders were habitual snorers and 5.8% complained of daytime sleepiness. From these, a group of 166 men highly suspected of having SAS was selected. Eventually, 61 of these came for all-night polysomnographic studies, and 15 of these were found to have SAS. On this basis the lower limit of the prevalence of SAS was estimated to be as high as 1.3%. The majority of subjects with the syndrome were in the age group 50-59 years.

Habitual coughing and its associations with asthma, anxiety, and gastroesophageal reflux.

STUDY OBJECTIVE: Coughing was studied in relation to different disorders and objective variables indicative of airway inflammation. SETTING: A random sample of 800 persons, aged 20 to 44 years, was chosen from a larger cohort of participants in the European Community Respiratory Health Survey in Uppsala Sweden; of these, 623 participated. This sample was enriched with 201 individuals who reported asthma-related symptoms or the use of asthma medication. METHODS: The study comprised a structured interview, including questions about habitual (productive and nonproductive) and nocturnal coughing and spirometry, methacholine challenge, peak flow diary, skin prick tests, and measurements of blood eosinophil count and serum eosinophil cationic protein (S-ECP). RESULTS: A significant positive correlation was found between productive coughing and asthma (adjusted odds ratios [OR] = 2.0), allergic rhinitis (OR = 1.9), gastroesophageal reflux (OR = 4.4), smoking (OR = 1.9), and anxiety (OR = 1.8), while nonproductive coughing was related to female gender (OR = 1.8) and anxiety (OR = 1.7). Nocturnal coughing was positively correlated to female gender (OR = 1.8), smoking (OR = 1.9), and asthma (OR = 2.2). Bronchial hyperresponsiveness was positively related to productive coughing (p < 0.001), nonproductive coughing, and nocturnal coughing (p < 0.05). S-ECP was significantly higher in individuals with nonproductive coughing compared with subjects without habitual coughing (p < 0.01). CONCLUSIONS: We conclude that habitual coughing has a significant association with different disease categories.

Increased CSF opioid activity in sleep apnea syndrome. Regression after successful treatment.

The etiology of the SAS is unknown. To test whether endogenous opioids could be pathologically active in SAS, markers of opioid systems were measured in the CSF of 15 patients with SAS and in control subjects. Measured by receptor assay, the concentration of so-called fraction 1 opioid was higher in patients with SAS (3.0 +/- 1.5 pmol/ml; mean +/- SD) than in control subjects (1.1 +/- 0.5 pmol/ml) (p less than 0.01), whereas that of fraction 2 opioid was similar in the two groups. Beta-endorphin-like activity, measured by radioimmunoassay, was somewhat lower in patients with SAS (14.0 +/- 2.8 pmol/ml) than in control subjects (21.8 +/- 7.6 pmol/ml) (p less than 0.05). Six months after surgical treatment of the soft palate, new measurements were made in eight patients. Fraction 2 endorphin and beta-endorphin showed no consistent changes. A decrease in the level of fraction 1 from 4.1 +/- 1.5 pmol/ml to 2.3 +/- 1.0 pmol/ml (p less than 0.02) was noted in those six patients showing a successful clinical course. The data support the hypothesis that in SAS the opioid activity is increased.

A 10-year follow-up of snoring in men.

STUDY OBJECTIVES: Little is known about the natural development of snoring, and this survey was conducted to study the development of snoring in men over a 10-year period. DESIGN: Population-based prospective survey. SETTING: The Municipality of Uppsala, Sweden. PARTICIPANTS AND MEASUREMENTS: In 1984, 3,201 randomly selected men aged 30 to 69 years answered a questionnaire on snoring and sleep disturbances. Of the 2,975 survivors in 1994, 2,668 (89.7%) answered a new questionnaire with identical questions to those used at baseline. Questions about smoking habits, alcohol, and physical activity were also added. RESULTS: Habitual snoring was reported by 393 men (15.0%) in 1984 and by 529 (20.4%) 10 years later. In both 1984 and 1994, the prevalence of snoring increased until age 50 to 60 years and then decreased. Risk factors for being a habitual snorer at the follow-up were investigated using multiple logistic regression with adjustments for previous snoring status, age, body mass index (BMI), weight gain, smoking habits, and physical activity. In men aged 30 to 49 years at baseline, the predictors of habitual snoring at the follow-up, in addition to previous snoring status, were as follows: persistent smoking (adjusted odds ratio, 95% confidence interval) (1.4, 1.1 to 1.9), BMI 1984 (1.1, 1.02 to 1.1/kg/m2) and weight gain (1.1, 1.03 to 1.2/kg/m2). Among men aged 50 to 69 years, after adjustments for previous snoring status and age, weight gain was the only significant risk factor for developing habitual snoring (1.2, 1.05 to 1.4/kg/m2). CONCLUSIONS: In men, the prevalence of snoring increases up to the age of 50 to 60 years and is then followed by a decrease. Weight gain is a risk factor for snoring in all age groups, while smoking is mainly associated with snoring in men <60 years of age.

Skin infection caused by Mycobacterium szulgai after allogeneic bone marrow transplantation.

Infections are responsible for a large part of the morbidity and mortality after BMT because of the sustained impairment of host defenses. We report a case of cutaneous infection caused by Mycobacterium szulgai in a boy who underwent BMT with marrow from a matched unrelated donor.

Bronchial hyperresponsiveness in two populations with different prevalences of atopy.

SETTING: Random population samples of young adults from Tartu, Estonia (n = 307) and Uppsala, Sweden (n = 498) in the framework of the European Community Respiratory Health Survey (ECRHS). OBJECTIVE: To compare the prevalence and risk factors for bronchial hyperresponsiveness (BHR) to methacholine in two centres with similar climate and ethnicity but differences in the prevalence of atopy, asthma and respiratory symptoms. DESIGN: General population-based cross-sectional survey. RESULTS: The prevalence of BHR using the cut-off points 1.5, 1.0 and 0.5 mg was 19%, 12% and 8% in Tartu and 11%, 7% and 2%, respectively, in Uppsala. Current smoking was a common risk factor for BHR in both centres. Female sex (odds ratio [OR] 2.9), sensitisation to cat (OR 5.9) and visible mould in the home (OR 2.4) were independent risk factors for BHR in Tartu. In Uppsala, BHR was significantly associated with total IgE levels (OR 2.0) and exposure to environmental tobacco smoke (OR 3.3). CONCLUSION: The high prevalence of BHR can explain the high prevalence of respiratory symptoms in Tartu and indicates that causes other than asthma and atopy can be responsible for the high prevalence of BHR in a population.

Symptoms related to the sick building syndrome in a general population sample: associations with atopy, bronchial hyper-responsiveness and anxiety.

OBJECTIVE: The sick building syndrome (SBS) is a term mainly applied to irritative symptoms in the eyes, skin and upper airways that are experienced in certain environments. The aim of this study was to investigate the characteristics of subjects from the general population that report SBS-related symptoms. METHODS: The study comprised a randomly selected population of 418 individuals aged 20-45 years. The subjects underwent a structured interview, skin prick tests, a methacholine provocation test and answered two questionnaires respectively assessing psychiatric status and the presence of SBS symptoms. RESULTS: Eighty-seven subjects (21%) reported one or more SBS symptom weekly. Most common were general symptoms reported by 10% of the population. Female sex (odds ratio [OR] = 2.1), atopy (OR = 2.2) and anxiety (OR = 2.6) were significant independent risk factors for reporting at least one SBS-related symptom. Anxiety (OR = 3.2) and depression (OR = 4.4) were significant predictors for general symptoms, while bronchial hyper-responsiveness was a significant predictor for pharyngeal symptoms (dryness in the throat, sore throat and irritating cough) (OR = 5.4). CONCLUSIONS: Sick building symptoms are common in the general population and among women, while atopy and anxiety increase the risk of reporting such symptoms. Psychological factors are mainly related to general symptoms, while bronchial hyperresponsiveness is connected with pharyngeal symptoms.