Incomplete restoration of the secretion of ghrelin and PYY compared to insulin after food ingestion following weight gain in anorexia nervosa

Assessing biomarkers of remission in female patients with anorexia nervosa (REMANO): a protocol for a prospective cohort study with a nested case-control study using clinical, neurocognitive, biological, genetic, epigenetic and neuroimaging markers in a French specialised inpatient unit

BACKGROUND

Anorexia nervosa (AN) is a severe psychiatric disorder associated with frequent relapses and variability in treatment responses. Previous literature suggested that such variability is influenced by premorbid vulnerabilities such as abnormalities of the reward system. Several factors may indicate these vulnerabilities, such as neurocognitive markers (tendency to favour delayed reward, poor cognitive flexibility, abnormal decision process), genetic and epigenetic markers, biological and hormonal markers, and physiological markers.The present study will aim to identify markers that can predict body mass index (BMI) stability 6 months after discharge. The secondary aim of this study will be focused on characterising the biological, genetic, epigenetic and neurocognitive markers of remission in AN.

METHODS AND ANALYSIS

One hundred and twenty-five (n=125) female adult inpatients diagnosed with AN will be recruited and evaluated at three different times: at the beginning of hospitalisation, when discharged and 6 months later. Depending on the BMI at the third visit, patients will be split into two groups: stable remission (BMI≥18.5 kg/m²) or unstable remission (BMI<18.5 kg/m²). One hundred (n=100) volunteers will be included as healthy controls.Each visit will consist in self-reported inventories (measuring depression, anxiety, suicidal thoughts and feelings, eating disorders symptoms, exercise addiction and the presence of comorbidities), neurocognitive tasks (Delay Discounting Task, Trail-Making Test, Brixton Test and Slip-of-action Task), the collection of blood samples, the repeated collection of blood samples around a standard meal and MRI scans at rest and while resolving a delay discounting task.Analyses will mainly consist in comparing patients stabilised 6 months later and patients who relapsed during these 6 months.

ETHICS AND DISSEMINATION

Investigators will ask all participants to give written informed consent prior to participation, and all data will be recorded anonymously. The study will be conducted according to ethics recommendations from the Helsinki declaration (World Medical Association, 2013). It was registered on clinicaltrials.gov on 25 August 2020 as 'Remission Factors in Anorexia Nervosa (REMANO)', with the identifier NCT04560517 (for more details, see https://clinicaltrials.gov/ct2/show/record/NCT04560517). The present article is based on the latest protocol version from 29 November 2019. The sponsor, Institut National de la Santé Et de la Recherche Médicale (INSERM, https://www.inserm.fr/), is an academic institution responsible for the monitoring of the study, with an audit planned on a yearly basis.The results will be published after final analysis in the form of scientific articles in peer-reviewed journals and may be presented at national and international conferences.

TRIAL REGISTRATION NUMBER

clinicaltrials.govNCT04560517.

The buffet challenge: a behavioral assessment of eating behavior in adolescents with an eating disorder

OBJECTIVE

Eating disorders are characterized by disturbances in nutritional intake and abnormal mealtime behaviors. Laboratory eating paradigms offer a unique opportunity to accurately measure dietary intake and eating behaviors, however, these studies have predominantly occurred in adults. This paper describes the development and preliminary psychometric examination of the Buffet Challenge, a laboratory-based meal task for youths with an eating disorder.

METHOD

We recruited and assessed 56 participants as part of a randomized controlled trial of Family-Based Treatment for adolescents with anorexia nervosa. Adolescents completed the Buffet Challenge at baseline, midway through treatment (~ week 16 of a 6 months course), and end of treatment. Participants and their parents also reported eating disorder symptomatology and treatment related variables of interest were recorded.

RESULTS

All adolescents were willing to complete the Buffet Challenge at all time points, although one refused to give up their cellphone, and there were no significant adverse events recorded. Preliminary results are presented.

CONCLUSIONS

Our initial pilot of this task in adolescents with anorexia nervosa demonstrates its acceptability, although investigation of our hypotheses was hindered by significant missing data due to COVID-related research shutdowns. Future studies should replicate procedures in a larger sample to ensure analyses are adequately powered.

Endocrinology of Underweight and Anorexia Nervosa

More than any other mental illness, the course, prognosis, and therapy of anorexia nervosa are shaped by the physical changes associated with being underweight. This article provides an overview of the endocrine changes associated with malnutrition and underweight. This overview serves as a basis for understanding the other articles in this special issue, which deal with the health risks associated with being underweight. In this context, the differences between underweight in anorexia nervosa and in constitutional thinness are of particular importance in assessing the impact of intentional weight loss. In this context, the regulation of hunger and satiety deserves special interest, as this is the area in which the intentional influence on body weight comes into play. Clinical consequences on, for example, fertility, bone metabolism, the homeostasis of, for example, serum glucose levels, or body temperature have been observed for a long time; nonetheless, the medical responses, apart from vitamin supplementations and advice to gain weight, are still limited. Therefore, emphasis was placed on the potential improvement of outcomes through the administration of central or peripheral hormones. Studies were identified on PubMed via a selection of relevant keywords; original texts that were cited in reviews were studied where it was advantageous. This review found some promising data on bone health and the administration of transdermal oestrogen, which is not yet widely used, as well as distinct hormonal markers to differentiate between CT and AN. We concluded that the continuous efforts to investigate the role of endocrinology in underweight and/or anorexia nervosa lead to outcome benefits and that more and higher-powered studies are needed.

Endocrine complications of anorexia nervosa

An important component in the treatment of anorexia nervosa (AN) is the evaluation and management of its endocrine complications, including functional hypogonadotropic hypogonadism and increased fracture risk. The body's adaptive response to chronic starvation results in many endocrine abnormalities, most of which are reversible upon weight restoration. A multidisciplinary team with experience in treating patients with AN is critical to improving endocrine outcomes in patients with this disorder, including in women with AN who are interested in fertility. Much less is understood about endocrine abnormalities in men, as well as sexual and gender minorities, with AN. In this article, we review the pathophysiology and evidence-based recommendations for the treatment of endocrine complications in AN, as well as discuss the status of clinical research in this area.

Eating disorders and carbohydrate metabolism interrelations

Introduction: Eating disorders are characterised by persistent disturbances in eating behavior, resulting in severe carbohydrate homeostasis changes. The aim of the study is to review mutual correlations between eating disorders, with emphasis on anorexia nervosa, and carbohydrate metabolism, including glycemia and the levels of relevant hormones.

Material and methods: A priori general inclusion criteria were established and included patients with eating disorders or with glucose metabolism disorders. A MEDLINE database review was carried out. Relevant articles have been extracted and approved by supervisor.

Results: 40 studies got included in the review. Patients with active anorexia nervosa display low levels of fasting and postprandial glucose, decreased lipid metabolism, and decreased pancreatic endocrine activity. Insulin levels remain changed even after patient’s re-nourishment – insulin response tends to be delayed and decreased compared to patients without anorexia history. Eating disorders are associated with poorer glycemic control and a higher percentage of diabetic complications in patients with pre-existing diabetes – mostly type I. There are also reports of higher carbohydrate metabolism disturbances among patients with eating disorders.

Conclusions: Carbohydrate metabolism disorders and eating disorders are clearly interrelated, although data on the nature of these relationships are still lacking. Treatment of eating disorders is not possible without normalizing eating patterns, thus also carbohydrate metabolism. However, it is not usual to monitor the mental state in terms of eating disorders potential development in patients during the treatment of carbohydrate disorders. According to existing data, this approach should be changed due to the risk of anorexia nervosa and other eating disorders in this group.

Dissociable hormonal profiles for psychopathology and stress in anorexia and bulimia nervosa

BACKGROUND

Anorexia nervosa (AN) and bulimia nervosa (BN) are complex psychiatric conditions, in which both psychological and metabolic factors have been implicated. Critically, the experience of stress can precipitate loss-of-control eating in both conditions, suggesting an interplay between mental state and metabolic signaling. However, associations between psychological states, symptoms and metabolic processes in AN and BN have not been examined.

METHODS

Eighty-five women (n = 22 AN binge/purge subtype, n = 33 BN, n = 30 controls) underwent remote salivary cortisol sampling and a 2-day, inpatient study session to examine the effect of stress on cortisol, gut hormones [acyl-ghrelin, peptide tyrosine tyrosine (PYY) and glucagon-like peptide-1] and food consumption. Participants were randomized to either an acute stress induction or control task on each day, and plasma hormones were serially measured before a naturalistic, ad libitum meal.

RESULTS

Cortisol-awakening response was augmented in AN but not in BN relative to controls, with body mass index explaining the most variance in post-awakening cortisol (36%). Acute stress increased acyl-ghrelin and PYY in AN compared to controls; however, stress did not alter gut hormone profiles in BN. Instead, a group-by-stress interaction showed nominally reduced cortisol reactivity in BN, but not in AN, compared to controls. Ad libitum consumption was lower in both patient groups and unaffected by stress.

CONCLUSIONS

Findings extend previous reports of metabolic dysfunction in binge-eating disorders, identifying unique associations across disorders and under stress. Moreover, we observed disrupted homeostatic signaling in AN following psychological stress, which may explain, in part, the maintenance of dysregulated eating in this serious illness.

Reframing anorexia nervosa as a metabo-psychiatric disorder

Anorexia nervosa (AN) is a serious and often fatal illness. Despite decades of research, investigators have failed to adequately advance our understanding of the biological aspects of AN that could inform the development of effective interventions. Genome-wide association studies are revealing the important role of metabolic factors in AN, and studies of the gastrointestinal tract are shedding light on disruptions in enteric microbial communities and anomalies in gut morphology. In this opinion piece, we review the state of the science through the lens of the clinical presentation of illness. We project how the integration of rigorous science in genomics and microbiology, in collaboration with experienced clinicians, has the potential to markedly enhance treatment outcome via precision interventions.

Gastrointestinal peptides in eating-related disorders

Food intake is tightly controlled by homeostatic signals sensitive to metabolic need for the regulation of body weight. This review focuses on the peripherally-secreted gastrointestinal peptides (i.e., ghrelin, cholecystokinin, glucagon-like peptide 1, and peptide tyrosine tyrosine) that contribute to the control of appetite and discusses how these peptides or the signals arising from their release are disrupted in eating-related disorders across the weight spectrum, namely anorexia nervosa, bulimia nervosa, and obesity, and whether they are normalized following weight restoration or weight loss treatment. Further, the role of gut peptides in the pathogenesis and treatment response in human weight conditions as identified by rodent models are discussed. Lastly, we review the incretin- and hormone-based pharmacotherapies available for the treatment of obesity and eating-related disorders.

Ghrelin and PYY in low-weight females with avoidant/restrictive food intake disorder compared to anorexia nervosa and healthy controls

BACKGROUND

Avoidant/restrictive food intake disorder (ARFID) is characterized by restrictive eating and failure to meet nutritional needs but is distinct from anorexia nervosa (AN) because restriction is not motivated by weight/shape concerns. We examined levels of orexigenic ghrelin and anorexigenic peptide YY (PYY) in young females with ARFID, AN and healthy controls (HC).

METHODS

94 females (22 low-weight ARFID, 40 typical/atypical AN, and 32 HC ages 10-22 years) underwent fasting blood draws for total ghrelin and total PYY. A subset also provided blood 30, 60 and 120 min after a standardized meal.

RESULTS

Females with ARFID ate less than those with AN or HC (ps<0.012); were younger (14.4 ± 3.2 years) than those with AN (18.9 ± 3.1 years) and HC (17.4 ± 3.1 years) (ps<0.003) and at a lower Tanner stage (3.1 ± 1.5) than AN (4.5 ± 1.1;) and HC (4.4 ± 1.1; ps<0.005), but did not differ in BMI percentiles or BMI Z-scores from AN (ps>0.44). Fasting and postprandial ghrelin were lower in ARFID versus AN (ps≤.015), but not HC (ps≥0.62). Fasting and postprandial PYY did not differ between ARFID versus AN or HC (ps≥0.13); ARFID did not demonstrate the sustained high PYY levels post-meal observed in those with AN and HC. Secondary analyses controlling age or Tanner stage and calories consumed showed similar results. Exploratory analyses suggest that the timing of the PYY peak in ARFID is earlier than HC, showing a peak PYY level 30 min post-meal (p = .037).

CONCLUSIONS

ARFID and AN appear to have distinct patterns of secretion of gut-derived appetite-regulating hormones that may aid in differential diagnosis and provide new treatment targets.

The regulation of gastric ghrelin secretion

Ghrelin is a gastric hormone with multiple physiological functions, including the stimulation of food intake and adiposity. It is well established that circulating ghrelin levels are closely associated with feeding patterns, rising strongly before a meal and lowering upon food intake. However, the mechanisms underlying the modulation of ghrelin secretion are not fully understood. The purpose of this review is to discuss current knowledge on the circadian oscillation of circulating ghrelin levels, the neural mechanisms stimulating fasting ghrelin levels and peripheral mechanisms modulating postprandial ghrelin levels. Furthermore, the therapeutic potential of targeting the ghrelin pathway is discussed in the context of the treatment of various metabolic disorders, including obesity, type 2 diabetes, diabetic gastroparesis and Prader-Willi syndrome. Moreover, eating disorders including anorexia nervosa, bulimia nervosa and binge-eating disorder are also discussed.

A Systematic Review and Meta-Analysis Finds Increased Blood Levels of All Forms of Ghrelin in Both Restricting and Binge-Eating/Purging Subtypes of Anorexia Nervosa

Anorexia nervosa (AN) is a severe psychiatric condition associated with high mortality and chronicity. The hunt for state, trait, subtyping, and prognostic biomarkers is ongoing and the orexigenic hormone ghrelin and its different forms, acyl ghrelin and desacyl ghrelin, have been proposed to be increased in AN, especially in the restrictive subtype. A systematic literature search was performed using established databases up to 30 November 2020. Forty-nine studies met inclusion criteria for cross-sectional and longitudinal meta-analyses on total ghrelin, acyl ghrelin, and desacyl ghrelin. All forms of ghrelin were increased in the acute stage of anorexia nervosa during fasting compared to healthy controls. Previous notions on differences in ghrelin levels between AN subtypes were not supported by current data. In addition, a significant decrease in total ghrelin was observed pre-treatment to follow-up. However, total ghrelin levels at follow-up were still marginally elevated compared to healthy controls, whereas for acyl ghrelin, no overall effect of treatment was observed. Due to heterogeneity in follow-up designs and only few data on long-term recovered patients, longitudinal results should be interpreted with caution. While the first steps towards a biomarker in acute AN have been completed, the value of ghrelin as a potential indicator of treatment success or recovery status or its use in subtype differentiation are yet to be established.

Increased plasma asprosin levels in patients with drug-naive anorexia nervosa

PURPOSE

Asprosin is a centrally acting appetite-promoting hormone and promotes glucose production in the liver. This study is the first to investigate the difference in asprosin in the plasma between anorexia nervosa (AN) and healthy controls, and to explore the relationship between asprosin changes and plasma glucose levels and AN symptoms.

METHODS

Plasma asprosin and glucose concentrations were detected in AN patients (n = 46) and healthy control subjects (n = 47). Eating Disorder Inventory-2 (EDI-2) was used to assess subjects' eating disorder symptoms and related personality traits. The patient's concomitant levels of depression and anxiety were also measured using the beck depression inventory and beck anxiety inventory, respectively.

RESULTS

Results indicate that AN patients had a higher asprosin concentration in their plasma compared to healthy controls (p = 0.033). Among AN patients, plasma asprosin levels correlated positively with EDI-2 interoceptive awareness subscale score (p = 0.030) and negatively with duration of illness (p = 0.036). Multiple linear regression analyses showed that increases in asprosin levels (p = 0.029), glucose levels (p = 0.024) and body mass index (p = 0.003) were associated with an increase of the score of EDI-2 bulimia subscale.

CONCLUSIONS

Our findings suggest that the increase in plasma asprosin concentration in patients with AN may be a compensation for the body's energy shortage, and asprosin may be involved in the development of bulimia and lack of interoceptive awareness in AN patients.

LEVEL OF EVIDENCE

Level III, case-control analytic study.

Current Aspects of the Role of Autoantibodies Directed Against Appetite-Regulating Hormones and the Gut Microbiome in Eating Disorders

The equilibrium and reciprocal actions among appetite-stimulating (orexigenic) and appetite-suppressing (anorexigenic) signals synthesized in the gut, brain, microbiome and adipose tissue (AT), seems to play a pivotal role in the regulation of food intake and feeding behavior, anxiety, and depression. A dysregulation of mechanisms controlling the energy balance may result in eating disorders such as anorexia nervosa (AN) and bulimia nervosa (BN). AN is a psychiatric disease defined by chronic self-induced extreme dietary restriction leading to an extremely low body weight and adiposity. BN is defined as out-of-control binge eating, which is compensated by self-induced vomiting, fasting, or excessive exercise. Certain gut microbiota-related compounds, like bacterial chaperone protein Escherichia coli caseinolytic protease B (ClpB) and food-derived antigens were recently described to trigger the production of autoantibodies cross-reacting with appetite-regulating hormones and neurotransmitters. Gut microbiome may be a potential manipulator for AT and energy homeostasis. Thus, the regulation of appetite, emotion, mood, and nutritional status is also under the control of neuroimmunoendocrine mechanisms by secretion of autoantibodies directed against neuropeptides, neuroactive metabolites, and peptides. In AN and BN, altered cholinergic, dopaminergic, adrenergic, and serotonergic relays may lead to abnormal AT, gut, and brain hormone secretion. The present review summarizes updated knowledge regarding the gut dysbiosis, gut-barrier permeability, short-chain fatty acids (SCFA), fecal microbial transplantation (FMT), blood-brain barrier permeability, and autoantibodies within the ghrelin and melanocortin systems in eating disorders. We expect that the new knowledge may be used for the development of a novel preventive and therapeutic approach for treatment of AN and BN.

Backstage of Eating Disorder-About the Biological Mechanisms behind the Symptoms of Anorexia Nervosa

Anorexia nervosa (AN) represents a disorder with the highest mortality rate among all psychiatric diseases, yet our understanding of its pathophysiological components continues to be fragmentary. This article reviews the current concepts regarding AN pathomechanisms that focus on the main biological aspects involving central and peripheral neurohormonal pathways, endocrine function, as well as the microbiome-gut-brain axis. It emerged from the unique complexity of constantly accumulating new discoveries, which hamper the ability to look at the disease in a more comprehensive way. The emphasis is placed on the mechanisms underlying the main symptoms and potential new directions that require further investigation in clinical settings.

Peptide YY3-36 concentration in acute- and long-term recovered anorexia nervosa

Purpose

The gut–brain axis could be a possible key factor in the pathophysiology of anorexia nervosa. The neuropeptide peptide YY_3–36, secreted by endocrine L cells of the gastrointestinal tract, is a known regulator of appetite and food intake. The objective of this study was to investigate peptide YY_3–36 plasma concentrations at different stages of anorexia nervosa in a combined cross-sectional and longitudinal design to differentiate between effects of acute undernutrition and more enduring characteristics.

Methods

We measured fasting plasma peptide YY_3–36 concentrations in young patients with acute anorexia nervosa (n = 47) and long-term recovered patients (n = 35) cross-sectionally in comparison to healthy control participants (n = 58), and longitudinally over the course of inpatient treatment. Physical activity was controlled as it may modulate peptide YY secretion.

Results

There was no group difference in peptide YY_3–36 concentration among young acutely underweight anorexia nervosa patients, long-term recovered anorexia nervosa patients, and healthy control participants. Longitudinally, there was no change in peptide YY_3–36 concentration after short-term weight rehabilitation. For acute anorexia nervosa patients at admission to treatment, there was a negative correlation between peptide YY_3–36 concentration and body mass index.

Conclusions

The current study provides additional evidence for a normal basal PYY_3–36 concentration in AN. Future studies should study multiple appetite-regulating peptides and their complex interplay and also use research designs including a food challenge.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02210-7) contains supplementary material, which is available to authorized users.

Changes in appetite-regulating hormones following food intake are associated with changes in reported appetite and a measure of hedonic eating in girls and young women with anorexia nervosa

BACKGROUND

Females with anorexia nervosa (AN) have higher ghrelin and peptide YY (PYY) and lower brain-derived neurotropic factor (BDNF) levels than controls, and differ in their perception of hunger cues. Studies have not examined appetite-regulating hormones in the context of homeostatic and hedonic appetite in AN.

OBJECTIVE

To examine whether alterations in appetite-regulating hormones following a standardized meal are associated with homeostatic and hedonic appetite in young females with AN vs. controls.

METHODS

68 females (36 AN, 32 controls) 10-22 years old were enrolled. Ghrelin, PYY and BDNF levels were assessed before, and 30, 60 and 120 min following a 400-kilocalorie standardized breakfast. Visual Analog Scales (VAS) assessing prospective food consumption, hunger, satiety, and hedonic appetite were administered before and 20 min after breakfast. A Cookie Taste Test (CTT) was conducted after a snack as a measure of hedonic eating behavior ∼3 h after breakfast.

RESULTS

AN had higher fasting ghrelin and PYY, and lower fasting BDNF (p = 0.001, 0.002 and 0.044 respectively) than controls. Following breakfast (over 120 min), ghrelin and PYY area under the curve (AUC) were higher, while BDNF AUC was lower in AN vs. controls (p = 0.007, 0.017 and 0.020 respectively). Among AN (but not controls), reductions in ghrelin and increases in PYY in the first 30-minutes following breakfast were associated with reductions in VAS scores for prospective food consumption. AN consumed fewer calories during the CTT vs. controls (p < 0.0001). In AN (particularly AN-restrictive subtype), BDNF AUC was positively associated with kilocalories consumed during the CTT CONCLUSIONS: In young females with AN, changes in ghrelin and PYY following food intake are associated with reductions in a prospective measure of food consumption, while reductions in BDNF are associated with reduced hedonic food intake. Further studies are necessary to better understand the complex interplay between appetite signals and eating behaviors in AN.

Neuroendocrinology of reward in anorexia nervosa and bulimia nervosa: Beyond leptin and ghrelin

The pathophysiology of anorexia nervosa (AN) and bulimia nervosa (BN) are still poorly understood, but psychobiological models have proposed a key role for disturbances in the neuroendocrines that signal hunger and satiety and maintain energy homeostasis. Mounting evidence suggests that many neuroendocrines involved in the regulation of homeostasis and body weight also play integral roles in food reward valuation and learning via their interactions with the mesolimbic dopamine system. Neuroimaging data have associated altered brain reward responses in this system with the dietary restriction and binge eating and purging characteristic of AN and BN. Thus, neuroendocrine dysfunction may contribute to or perpetuate eating disorder symptoms via effects on reward circuitry. This narrative review focuses on reward-related neuroendocrines that are altered in eating disorder populations, including peptide YY, insulin, stress and gonadal hormones, and orexins. We provide an overview of the animal and human literature implicating these neuroendocrines in dopaminergic reward processes and discuss their potential relevance to eating disorder symptomatology and treatment.

Body composition in anorexia nervosa: Meta-analysis and meta-regression of cross-sectional and longitudinal studies

OBJECTIVE

Clinically, anorexia nervosa (AN) presents with altered body composition. We quantified these alterations and evaluated their relationships with metabolites and hormones in patients with AN longitudinally.

METHOD

In accordance with PRISMA guidelines, we conducted 94 meta-analyses on 62 samples published during 1996-2019, comparing up to 2,319 pretreatment, posttreatment, and weight-recovered female patients with AN with up to 1,879 controls. Primary outcomes were fat mass, fat-free mass, body fat percentage, and their regional distribution. Secondary outcomes were bone mineral density, metabolites, and hormones. Meta-regressions examined relationships among those measures and moderators.

RESULTS

Pretreatment female patients with AN evidenced 50% lower fat mass (mean difference [MD]: -8.80 kg, 95% CI: -9.81, -7.79, Q = 1.01 × 10-63 ) and 4.98 kg (95% CI: -5.85, -4.12, Q = 1.99 × 10-28 ) lower fat-free mass, with fat mass preferentially stored in the trunk region during early weight restoration (4.2%, 95% CI: -2.1, -6.2, Q = 2.30 × 10-4 ). While the majority of traits returned to levels seen in healthy controls after weight restoration, fat-free mass (MD: -1.27 kg, 95% CI: -1.79, -0.75, Q = 5.49 × 10-6 ) and bone mineral density (MD: -0.10 kg, 95% CI: -0.18, -0.03, Q = 0.01) remained significantly altered.

DISCUSSION

Body composition is markedly altered in AN, warranting research into these phenotypes as clinical risk or relapse predictors. Notably, the long-term altered levels of fat-free mass and bone mineral density suggest that these parameters should be investigated as potential AN trait markers.

RESUMENOBJETIVO

Clínicamente, la anorexia nervosa (AN) se presenta con alteraciones en la composición corporal. Cuantificamos estas alteraciones y evaluamos longitudinalmente su relación con metabolitos y hormonas en pacientes con AN. MÉTODO: De acuerdo con las pautas PRISMA, realizamos 94 meta-análisis en 62 muestras publicadas entre 1996-2019, comparando hasta 2,319 pacientes mujeres en pre-tratamiento, post-tratamiento, y recuperadas en base al peso con hasta 1,879 controles. Las principales medidas fueron masa grasa, masa libre de grasa, porcentaje de grasa corporal y su distribución regional. Las medidas secundarias fueron densidad mineral ósea, metabolitos y hormonas. Las meta-regresiones examinaron las relaciones entre esas medidas y moderadores.

RESULTADOS

Las pacientes femeninas con AN pre-tratamiento mostraron un 50% menos de masa grasa (MD: -8.80 kg, CI 95%: -9.81, -7.79, Q = 1.01 × 10-63 ) y 4.98 kg (CI 95%: -5.85, -4.12, Q = 1.99 × 10-28 ) menos de masa libre de grasa, con masa grasa preferentemente almacenada en la región del tronco durante la recuperación temprana del peso (4.2%, CI 95%: -2.1, -6.2, Q = 2.30 × 10-4 ). Aunque la mayoría de los rasgos regresaron a los niveles vistos en los controles sanos después de la restauración del peso, la masa libre de grasa (MD: -1.27 kg, CI 95%: -1.79, -0.75, Q = 5.49 × 10-6 ) y la densidad mineral ósea (MD: -0.10 kg, CI 95%: -0.18, -0.03, Q = 0.01) permanecieron significativamente alteradas. DISCUSIÓN: La composición corporal es marcadamente alterada en la AN, lo que garantiza la investigación en estos fenotipos como predictores de riesgo clínico o de recaída. Notablemente, la alteración a largo plazo de los niveles de masa libre de grasa y densidad mineral ósea sugieren que estos parámetros debe ser investigados como potenciales rasgos indicadores de AN.

Menopause is associated with decreased postprandial ghrelin, whereas a history of anorexia nervosa is associated with increased total ghrelin

Middle age has been linked with various dysfunctional eating patterns in women. The hormone ghrelin is related to food intake, with plasma levels rising before eating and decreasing immediately afterwards. Animal research has shown that oestradiol is an antagonist of ghrelin. Given that both menopause and anorexia nervosa (AN) are states characterised by reduced oestradiol, the present study aimed to investigate for the first time whether menopausal status and a history of AN are linked with altered ghrelin levels in middle-aged women. Based on previous research, we hypothesised that (i) post-menopausal women would demonstrate comparably increased ghrelin after food intake and (ii) women with a history of AN would exhibit increased total ghrelin levels. Healthy, middle-aged women (n = 57) were recruited. Of the women, 31 were post-menopausal and 27 had a history of AN. Plasma ghrelin was repeatedly collected before and after a meal standardised in terms of caloric content. Areas under the curves were calculated to indicate total (AUCg) and postprandial ghrelin (AUCi). Menopausal status was linked with postprandial ghrelin (AUCi -1.6 ± 2.2 vs -2.9 ± 2.6; P = 0.058), whereas a history of AN was linked with total ghrelin (AUCg 36.2 ± 5.6 vs 39.0 ± 3.7; P = 0.050). There were no interaction effects (both P > 0.466). A closer examination of the effects revealed that post-menopausal women showed marginally greater decreases in ghrelin immediately after food intake (P = 0.064) and marginally greater re-increases after 60 minutes (P = 0.084) compared to pre-menopausal women. Women with a history of AN had significantly higher total ghrelin compared to women without a history of AN (P = 0.042). Post-menopause was linked with higher sensitivity of ghrelin to food intake (trend), whereas a history of AN was related to greater total ghrelin. Future research should investigate to what extent the observed alterations in ghrelin may affect dysfunctional eating behaviour during middle age.

Appetite Perceptions, Gastrointestinal Symptoms, Ghrelin, Peptide YY and State Anxiety Are Disturbed in Adolescent Females with Anorexia Nervosa and Only Partially Restored with Short-Term Refeeding

Factors underlying disturbed appetite perception in anorexia nervosa (AN) are poorly characterized. We examined in patients with AN whether fasting and postprandial appetite perceptions, gastrointestinal (GI) hormones, GI symptoms and state anxiety (i) differed from healthy controls (HCs) and (ii) were modified by two weeks of refeeding. 22 female adolescent inpatients with restricting AN, studied on hospital admission once medically stable (Wk0), and after one (Wk1) and two (Wk2) weeks of high-calorie refeeding, were compared with 17 age-matched HCs. After a 4 h fast, appetite perceptions, GI symptoms, state anxiety, and plasma acyl-ghrelin, cholecystokinin (CCK), peptide tyrosine tyrosine (PYY) and pancreatic polypeptide (PP) concentrations were assessed at baseline and in response to a mixed-nutrient test-meal (479 kcal). Compared with HCs, in patients with AN at Wk0, baseline ghrelin, PYY, fullness, bloating and anxiety were higher, and hunger less, and in response to the meal, ghrelin, bloating and anxiety were greater, and hunger less (all p < 0.05). After two weeks of refeeding, there was no change in baseline or postprandial ghrelin or bloating, or postprandial anxiety, but baseline PYY, fullness and anxiety decreased, and baseline and postprandial hunger increased (p < 0.05). We conclude that in AN, refeeding for 2 weeks was associated with improvements in PYY, appetite and baseline anxiety, while increased ghrelin, bloating and postprandial anxiety persisted.

The Neuroendocrinology of the Microbiota-Gut-Brain Axis: A Behavioural Perspective

The human gut harbours trillions of symbiotic bacteria that play a key role in programming different aspects of host physiology in health and disease. These intestinal microbes are also key components of the gut-brain axis, the bidirectional communication pathway between the gut and the central nervous system (CNS). In addition, the CNS is closely interconnected with the endocrine system to regulate many physiological processes. An expanding body of evidence is supporting the notion that gut microbiota modifications and/or manipulations may also play a crucial role in the manifestation of specific behavioural responses regulated by neuroendocrine pathways. In this review, we will focus on how the intestinal microorganisms interact with elements of the host neuroendocrine system to modify behaviours relevant to stress, eating behaviour, sexual behaviour, social behaviour, cognition and addiction.

The Role of Ghrelin in Anorexia Nervosa

Ghrelin, a 28-amino acid peptide hormone expressed in X/A-like endocrine cells of the stomach, is the only known peripherally produced and centrally acting peptide that stimulates food intake and therefore attracted a lot of attention with one major focus on the treatment of conditions where an increased energy intake or body weight gain is desired. Anorexia nervosa is an eating disorder characterized by a pronounced reduction of body weight, a disturbed body image and hormonal alterations. Ghrelin signaling has been thoroughly investigated under conditions of anorexia nervosa. The present review will highlight these alterations of ghrelin in anorexia and discuss possible treatment strategies targeting ghrelin signaling. Lastly, gaps in knowledge will be mentioned to foster future research.

Toward valid and reliable brain imaging results in eating disorders

Human brain imaging can help improve our understanding of mechanisms underlying brain function and how they drive behavior in health and disease. Such knowledge may eventually help us to devise better treatments for psychiatric disorders. However, the brain imaging literature in psychiatry and especially eating disorders has been inconsistent, and studies are often difficult to replicate. The extent or severity of extremes of eating and state of illness, which are often associated with differences in, for instance hormonal status, comorbidity, and medication use, commonly differ between studies and likely add to variation across study results. Those effects are in addition to the well-described problems arising from differences in task designs, data quality control procedures, image data preprocessing and analysis or statistical thresholds applied across studies. Which of those factors are most relevant to improve reproducibility is still a question for debate and further research. Here we propose guidelines for brain imaging research in eating disorders to acquire valid results that are more reliable and clinically useful.

Bone metabolism in anorexia nervosa and hypothalamic amenorrhea

Anorexia nervosa (AN) and hypothalamic amenorrhea (HA) are states of chronic energy deprivation associated with severely compromised bone health. Poor bone accrual during adolescence followed by increased bone loss results in lifelong low bone density, degraded bone architecture, and higher risk of fractures, despite recovery from AN/HA. Amenorrhea is only one of several compensatory responses to the negative energy balance. Other hypothalamic-pituitary hormones are affected and contribute to bone deficits, including activation of hypothalamic-pituitary-adrenal axis and growth hormone resistance. Adipokines, particularly leptin, provide information on fat/energy stores, and gut hormones play a role in the regulation of appetite and food intake. Alterations in all these hormones influence bone metabolism. Restricted in scope, current pharmacologic approaches to improve bone health have had overall limited success.

The endocrine manifestations of anorexia nervosa: mechanisms and management

Anorexia nervosa is a psychiatric disorder characterized by altered body image, persistent food restriction and low body weight, and is associated with global endocrine dysregulation in both adolescent girls and women. Dysfunction of the hypothalamic-pituitary axis includes hypogonadotropic hypogonadism with relative oestrogen and androgen deficiency, growth hormone resistance, hypercortisolaemia, non-thyroidal illness syndrome, hyponatraemia and hypooxytocinaemia. Serum levels of leptin, an anorexigenic adipokine, are suppressed and levels of ghrelin, an orexigenic gut peptide, are elevated in women with anorexia nervosa; however, levels of peptide YY, an anorexigenic gut peptide, are paradoxically elevated. Although most, but not all, of these endocrine disturbances are adaptive to the low energy state of chronic starvation and reverse with treatment of the eating disorder, many contribute to impaired skeletal integrity, as well as neuropsychiatric comorbidities, in individuals with anorexia nervosa. Although 5-15% of patients with anorexia nervosa are men, only limited data exist regarding the endocrine impact of the disease in adolescent boys and men. Further research is needed to understand the endocrine determinants of bone loss and neuropsychiatric comorbidities in anorexia nervosa in both women and men, as well as to formulate optimal treatment strategies.

The physiology of functional hypothalamic amenorrhea associated with energy deficiency in exercising women and in women with anorexia nervosa

An energy deficiency is the result of inadequate energy intake relative to high energy expenditure. Often observed with the development of an energy deficiency is a high drive for thinness, dietary restraint, and weight and shape concerns in association with eating behaviors. At a basic physiologic level, a chronic energy deficiency promotes compensatory mechanisms to conserve fuel for vital physiologic function. Alterations have been documented in resting energy expenditure (REE) and metabolic hormones. Observed metabolic alterations include nutritionally acquired growth hormone resistance and reduced insulin-like growth factor-1 (IGF-1) concentrations; hypercortisolemia; increased ghrelin, peptide YY, and adiponectin; and decreased leptin, triiodothyronine, and kisspeptin. The cumulative effect of the energetic and metabolic alterations is a suppression of the hypothalamic-pituitary-ovarian axis. Gonadotropin releasing hormone secretion is decreased with consequent suppression of luteinizing hormone and follicle stimulating hormone release. Alterations in hypothalamic-pituitary secretion alters the production of estrogen and progesterone resulting in subclinical or clinical menstrual dysfunction.

Anorexia Nervosa and Its Associated Endocrinopathy in Young People

Anorexia nervosa (AN) is a condition of severe undernutrition associated with adaptive changes in many endocrine axes. These changes include hypogonadotropic hypogonadism, acquired growth hormone resistance with low insulin-like growth factor 1 (IGF-1) levels, hypercortisolemia, altered secretion of adipokines and appetite-regulating hormones, and low bone mineral density (BMD). Bone health is impaired subsequent to a low body mass index, decreased lean mass, and the endocrine changes described above. In addition to low areal BMD, AN is characterized by a decrease in volumetric BMD, changes in bone geometry, and reductions in strength estimates, leading to an increased risk for fracture. Weight restoration is essential for restoration of normal endocrine function; however, hypercortisolemia, high peptide YY levels, and ghrelin dynamics may not completely normalize. In some patients, hypogonadotropic hypogonadism persists despite weight restoration. Weight gain and menstrual recovery are critical for improving bone health in AN; however, residual deficits may persist. Physiologic estrogen replacement using transdermal, but not oral, estrogen increases bone accrual in adolescents with AN, while bisphosphonates improve BMD in adults. Recombinant human IGF-1 and teriparatide have been used in a few studies as bone anabolic therapies. More data are necessary to determine the optimal therapeutic strategies for low BMD in AN.

One-year intranasal application of growth hormone releasing peptide-2 improves body weight and hypoglycemia in a severely emaciated anorexia nervosa patient

BACKGROUND

In Japan, growth hormone releasing peptide-2 (GHRP-2) is clinically used as a diagnostic agent for growth hormone secretion deficiency, but the therapeutic application of GHRP-2 has not been studied in anorexia nervosa. GHRP-2 reportedly exhibits agonistic action for ghrelin receptor and increases food intake.

METHODS

We administered GHRP-2 to a patient with a 20-year history of anorexia nervosa to determine whether GHRP-2 treatment increases food intake and body weight. GHRP-2 was administered before every meal by an intranasal approach for 1 year.

RESULTS

Although the patient reported a decreased fear of eating and decreased desire to be thin by our previous treatment, she was unable to increase food intake or body weight because of digestive tract dysfunction. Vomiting after meals caused by delayed gastric emptying and incurable constipation were prolonged, and sub-ileus and hypoglycemia were observed. GHRP-2 increased the feeling of hunger and food intake, decreased early satiety and improved hypoglycemia. The patient's body weight gradually increased by 6.7 kg (from 21.1 kg to 27.8 kg) in 14 months after starting GHRP-2 administration. The fatigability and muscle strength improved, and the physical and mental activities were also increased. No obvious side effects were observed after long-term intranasal administration of GHRP-2.

CONCLUSIONS

Patients with a long-term history of eating disorder occasionally recover from the psychological problems such as fear for obesity but remain emaciated. We believe that ghrelin agonists such as GHRP-2 may be promising agents for the effective treatments of severe anorexia nervosa in a chronic condition.

Ghrelin in psychiatric disorders - A review

Ghrelin is a 28-amino-acid peptide hormone, first described in 1999 and broadly expressed in the organism. As the only known orexigenic hormone secreted in the periphery, it increases hunger and appetite, promoting food intake. Ghrelin has also been shown to be involved in various physiological processes being regulated in the central nervous system such as sleep, mood, memory and reward. Accordingly, it has been implicated in a series of psychiatric disorders, making it subject of increasing investigation, with knowledge rapidly accumulating. This review aims at providing a concise yet comprehensive overview of the role of ghrelin in psychiatric disorders. Ghrelin was consistently shown to exert neuroprotective and memory-enhancing effects and alleviated psychopathology in animal models of dementia. Few human studies show a disruption of the ghrelin system in dementia. It was also shown to play a crucial role in the pathophysiology of addictive disorders, promoting drug reward, enhancing drug seeking behavior and increasing craving in both animals and humans. Ghrelin's exact role in depression and anxiety is still being debated, as it was shown to both promote and alleviate depressive and anxiety-behavior in animal studies, with an overweight of evidence suggesting antidepressant effects. Not surprisingly, the ghrelin system is also implicated in eating disorders, however its exact role remains to be elucidated. Its widespread involvement has made the ghrelin system a promising target for future therapies, with encouraging findings in recent literature.

Appetite regulatory hormones in women with anorexia nervosa: binge-eating/purging versus restricting type

OBJECTIVE

Anorexia nervosa is a psychiatric illness characterized by low weight, disordered eating, and hallmark neuroendocrine dysfunction. Behavioral phenotypes are defined by predominant restriction or bingeing/purging; binge-eating/purging type anorexia nervosa is associated with poorer outcome. The pathophysiology underlying anorexia nervosa types is unknown, but altered hormones, known to be involved in eating behaviors, may play a role.

METHOD

To examine the role of anorexigenic hormones in anorexia nervosa subtypes, we examined serum levels of peptide YY (PYY; total and active [3-36] forms), brain-derived neurotrophic factor (BDNF), and leptin as primary outcomes in women with DSM-5 restricting type anorexia nervosa (n = 50), binge-eating/purging type anorexia nervosa (n = 25), and healthy controls (n = 22). In addition, women completed validated secondary outcome measures of eating disorder psychopathology (Eating Disorder Examination-Questionnaire) and depression and anxiety symptoms (Hamilton Rating Scales for Depression [HDRS] and Anxiety [HARS]). The study samples were collected from May 22, 2004, to February 7, 2012.

RESULTS

Mean PYY 3-36 and leptin levels were lower and BDNF levels higher in binge-eating/purging type anorexia nervosa than in restricting type anorexia nervosa (all P values < .05). After controlling for body mass index, differences in PYY and PYY 3-36 between anorexia nervosa types were significant (P < .05) and differences in BDNF were at the trend level (P < .10). PYY 3-36 was positively (r = 0.27, P = .02) and leptin was negatively (r = -0.51, P < .0001) associated with dietary restraint; BDNF was positively associated with frequency of purging (r = 0.21, P = .04); and leptin was negatively associated with frequency of bingeing (r = -0.29, P = .007) and purging (r = -0.31, P = .004).

CONCLUSIONS

Among women with anorexia nervosa, the anorexigenic hormones PYY, BDNF, and leptin are differentially regulated between the restricting and binge/purge types. Whether these hormone pathways play etiologic roles with regard to anorexia nervosa behavioral types or are compensatory merits further study.

Abnormal relationships between the neural response to high- and low-calorie foods and endogenous acylated ghrelin in women with active and weight-recovered anorexia nervosa

Evidence contributing to the understanding of neurobiological mechanisms underlying appetite dysregulation in anorexia nervosa draws heavily on separate lines of research into neuroendocrine and neural circuitry functioning. In particular, studies consistently cite elevated ghrelin and abnormal activation patterns in homeostatic (hypothalamus) and hedonic (striatum, amygdala, insula) regions governing appetite. The current preliminary study examined the interaction of these systems, based on research demonstrating associations between circulating ghrelin levels and activity in these regions in healthy individuals. In a cross-sectional design, we studied 13 women with active anorexia nervosa (AN), 9 women weight-recovered from AN (AN-WR), and 12 healthy-weight control women using a food cue functional magnetic resonance imaging paradigm, with assessment of fasting levels of acylated ghrelin. Healthy-weight control women exhibited significant positive associations between fasting acylated ghrelin and activity in the right amygdala, hippocampus, insula, and orbitofrontal cortex in response to high-calorie foods, associations which were absent in the AN and AN-WR groups. Women with AN-WR demonstrated a negative relationship between ghrelin and activity in the left hippocampus in response to high-calorie foods, while women with AN showed a positive association between ghrelin and activity in the right orbitofrontal cortex in response to low-calorie foods. Findings suggest a breakdown in the interaction between ghrelin signaling and neural activity in relation to reward responsivity in AN, a phenomenon that may be further characterized using pharmacogenetic studies.

Central and peripheral peptides regulating eating behaviour and energy homeostasis in anorexia nervosa and bulimia nervosa: a literature review

A large body of literature suggests the occurrence of a dysregulation in both central and peripheral modulators of appetite in patients with anorexia nervosa (AN) and bulimia nervosa (BN), but at the moment, the state or trait-dependent nature of those changes is far from being clear. It has been proposed, although not definitively proved, that peptide alterations, even when secondary to malnutrition and/or to aberrant eating behaviours, might contribute to the genesis and the maintenance of some symptomatic aspects of AN and BN, thus affecting the course and the prognosis of these disorders. This review focuses on the most significant literature studies that explored the physiology of those central and peripheral peptides, which have prominent effects on eating behaviour, body weight and energy homeostasis in patients with AN and BN. The relevance of peptide dysfunctions for the pathophysiology of eating disorders is critically discussed.

Neuroactive peptides as putative mediators of antiepileptic ketogenic diets

Various ketogenic diet (KD) therapies, including classic KD, medium chain triglyceride administration, low glycemic index treatment, and a modified Atkins diet, have been suggested as useful in patients affected by pharmacoresistant epilepsy. A common goal of these approaches is to achieve an adequate decrease in the plasma glucose level combined with ketogenesis, in order to mimic the metabolic state of fasting. Although several metabolic hypotheses have been advanced to explain the anticonvulsant effect of KDs, including changes in the plasma levels of ketone bodies, polyunsaturated fatty acids, and brain pH, direct modulation of neurotransmitter release, especially purinergic (i.e., adenosine) and γ-aminobutyric acidergic neurotransmission, was also postulated. Neuropeptides and peptide hormones are potent modulators of synaptic activity, and their levels are regulated by metabolic states. This is the case for neuroactive peptides such as neuropeptide Y, galanin, cholecystokinin, and peptide hormones such as leptin, adiponectin, and growth hormone-releasing peptides (GHRPs). In particular, the GHRP ghrelin and its related peptide des-acyl ghrelin are well-known controllers of energy homeostasis, food intake, and lipid metabolism. Notably, ghrelin has also been shown to regulate the neuronal excitability and epileptic activation of neuronal networks. Several lines of evidence suggest that GHRPs are upregulated in response to starvation and, particularly, in patients affected by anorexia and cachexia, all conditions in which also ketone bodies are upregulated. Moreover, starvation and anorexia nervosa are accompanied by changes in other peptide hormones such as adiponectin, which has received less attention. Adipocytokines such as adiponectin have also been involved in modulating epileptic activity. Thus, neuroactive peptides whose plasma levels and activity change in the presence of ketogenesis might be potential candidates for elucidating the neurohormonal mechanisms involved in the beneficial effects of KDs. In this review, we summarize the current evidence for altered regulation of the synthesis of neuropeptides and peripheral hormones in response to KDs, and we try to define a possible role for specific neuroactive peptides in mediating the antiepileptic properties of diet-induced ketogenesis.

Ghrelin decreases firing activity of gonadotropin-releasing hormone (GnRH) neurons in an estrous cycle and endocannabinoid signaling dependent manner

The orexigenic peptide, ghrelin is known to influence function of GnRH neurons, however, the direct effects of the hormone upon these neurons have not been explored, yet. The present study was undertaken to reveal expression of growth hormone secretagogue receptor (GHS-R) in GnRH neurons and elucidate the mechanisms of ghrelin actions upon them. Ca²⁺-imaging revealed a ghrelin-triggered increase of the Ca²⁺-content in GT1-7 neurons kept in a steroid-free medium, which was abolished by GHS-R-antagonist JMV2959 (10µM) suggesting direct action of ghrelin. Estradiol (1nM) eliminated the ghrelin-evoked rise of Ca²⁺-content, indicating the estradiol dependency of the process. Expression of GHS-R mRNA was then confirmed in GnRH-GFP neurons of transgenic mice by single cell RT-PCR. Firing rate and burst frequency of GnRH-GFP neurons were lower in metestrous than proestrous mice. Ghrelin (40nM-4μM) administration resulted in a decreased firing rate and burst frequency of GnRH neurons in metestrous, but not in proestrous mice. Ghrelin also decreased the firing rate of GnRH neurons in males. The ghrelin-evoked alterations of the firing parameters were prevented by JMV2959, supporting the receptor-specific actions of ghrelin on GnRH neurons. In metestrous mice, ghrelin decreased the frequency of GABAergic mPSCs in GnRH neurons. Effects of ghrelin were abolished by the cannabinoid receptor type-1 (CB1) antagonist AM251 (1µM) and the intracellularly applied DAG-lipase inhibitor THL (10µM), indicating the involvement of retrograde endocannabinoid signaling. These findings demonstrate that ghrelin exerts direct regulatory effects on GnRH neurons via GHS-R, and modulates the firing of GnRH neurons in an ovarian-cycle and endocannabinoid dependent manner.

Dysfunctions of leptin, ghrelin, BDNF and endocannabinoids in eating disorders: beyond the homeostatic control of food intake

A large body of literature documents the occurrence of alterations in the physiology of both central and peripheral modulators of appetite in acute patients with anorexia nervosa (AN) and bulimia nervosa (BN). Until more recently the role of most of the appetite modulators in the control of eating behavior was conceptualized solely in terms of their influence on homeostatic control of energy balance. However, it is becoming more and more evident that appetite modulators also affect the non-homeostatic cognitive, emotional and rewarding component of food intake as well as non food-related reward, and, recently, AN and BN have been pathophysiologically linked to dysfunctions of reward mechanisms. Therefore, the possibility exists that observed changes in appetite modulators in acute AN and BN may represent not only homeostatic adaptations to malnutrition, but also contribute to the development and/or the maintenance of aberrant non-homeostatic behaviors, such as self-starvation and binge eating. In the present review, the evidences supporting a role of leptin, ghrelin, brain-derived neurotrophic factor and endocannabinoids in the homeostatic and non-homeostatic dysregulations of patients with AN and BN will be presented. The reviewed literature is highly suggestive that changes in the physiology of these modulators may play a pivotal role in the pathophysiology of eating disorders by providing a possible link between motivated behaviors, reward processes, cognitive functions and energy balance.

Gut hormones, appetite suppression and cachexia in patients with pulmonary TB

Background

Cachexia is a hallmark of pulmonary tuberculosis and is associated with poor prognosis. A better understanding of the mechanisms behind such weight loss could reveal targets for therapeutic intervention. The role of appetite-regulatory hormones in tuberculosis is unknown.

Methods and Findings

41 subjects with newly-diagnosed pulmonary TB (cases) were compared to 82 healthy controls. We measured appetite, body mass index (BMI), % body fat (BF), plasma peptide YY (PYY), leptin, ghrelin, and resistin for all subjects. Measurements were taken at baseline for controls and at treatment days 0, 30, and 60 for cases. Baseline appetite, BMI, and BF were lower in cases than in controls and improved during treatment. PYY, ghrelin, and resistin were significantly elevated in cases and fell during treatment. Leptin was lower in cases and rose with treatment. Appetite was inversely related to PYY in cases. High pre-treatment PYY predicted reduced gains in appetite and BF. PYY was the strongest independent predictor of appetite in cases across all time points.

Conclusions

Appetite-regulatory hormones are altered in TB patients. As hormones normalize during treatment, appetite is restored and nutritional status improves. High baseline PYY is an indicator of poor prognosis for improvement in appetite and nutrition during treatment. Wasting in TB patients may partly be mediated by upregulation of PYY with resulting appetite suppression.

Ghrelin and eating disorders

There is growing evidence supporting a multifactorial etiology that includes genetic, neurochemical, and physiological components for eating disorders above and beyond the more conventional theories based on psychological and sociocultural factors. Ghrelin is one of the key gut signals associated with appetite, and the only known circulating hormone that triggers a positive energy balance by stimulating food intake. This review summarizes recent findings and several conflicting reports on ghrelin in eating disorders. Understanding these findings and inconsistencies may help in developing new methods to prevent and treat patients with these disorders.

The role of "mixed" orexigenic and anorexigenic signals and autoantibodies reacting with appetite-regulating neuropeptides and peptides of the adipose tissue-gut-brain axis: relevance to food intake and nutritional status in patients with anorexia nervosa and bulimia nervosa

Eating disorders such as anorexia (AN) and bulimia nervosa (BN) are characterized by abnormal eating behavior. The essential aspect of AN is that the individual refuses to maintain a minimal normal body weight. The main features of BN are binge eating and inappropriate compensatory methods to prevent weight gain. The gut-brain-adipose tissue (AT) peptides and neutralizing autoantibodies play an important role in the regulation of eating behavior and growth hormone release. The mechanisms for controlling food intake involve an interplay between gut, brain, and AT. Parasympathetic, sympathetic, and serotoninergic systems are required for communication between brain satiety centre, gut, and AT. These neuronal circuits include neuropeptides ghrelin, neuropeptide Y (NPY), peptide YY (PYY), cholecystokinin (CCK), leptin, putative anorexigen obestatin, monoamines dopamine, norepinephrine (NE), serotonin, and neutralizing autoantibodies. This extensive and detailed report reviews data that demonstrate that hunger-satiety signals play an important role in the pathogenesis of eating disorders. Neuroendocrine dysregulations of the AT-gut-brain axis peptides and neutralizing autoantibodies may result in AN and BN. The circulating autoantibodies can be purified and used as pharmacological tools in AN and BN. Further research is required to investigate the orexigenic/anorexigenic synthetic analogs and monoclonal antibodies for potential treatment of eating disorders in clinical practice.

Decreased luteinizing hormone pulse frequency is associated with elevated 24-hour ghrelin after calorie restriction and exercise in premenopausal women

Elevated ghrelin has been shown to be associated with reduced luteinizing hormone (LH) pulsatility in Rhesus monkeys, rats, men, and recently women. We previously reported that 24-h ghrelin concentrations are elevated in women following a 3-mo exercise and diet program leading to weight loss. We investigated whether the elevations in ghrelin following an ~3-mo exercise and diet program leading to weight loss are associated with a decrease in LH pulsatility. The nonexercising control group (Control, n = 5) consumed a controlled diet that matched energy needs, whereas energy intake in the exercise group (Energy Deficit, n = 16) was reduced from baseline energy requirements and supervised exercise training occurred five times per a week. Significant decreases in body weight (-3.0 ± 0.6 kg), body fat (-2.9 ± 0.4 kg) and 24-h LH pulse frequency (-0.18 ± 0.08 pulses/h), and a significant increase in 24-h mean ghrelin were observed in only the Energy Deficit group. The pre-post change in LH pulse frequency was negatively correlated with the change in mean 24-h ghrelin (R = -0.485, P = 0.030) and the change in peak ghrelin at lunch (R = -0.518, P = 0.019). Interestingly, pre-post change in night LH pulse frequency was negatively correlated with the change in mean day ghrelin (R = -0.704, P = 0.001). Elevated total ghrelin concentrations are associated with the suppression of LH pulsatility in premenopausal women and may play a role in the suppression of reproductive function following weight loss.

Ghrelin: central and peripheral implications in anorexia nervosa

Increasing clinical and therapeutic interest in the neurobiology of eating disorders reflects their dramatic impact on health. Chronic food restriction resulting in severe weight loss is a major symptom described in restrictive anorexia nervosa (AN) patients, and they also suffer from metabolic disturbances, infertility, osteopenia, and osteoporosis. Restrictive AN, mostly observed in young women, is the third largest cause of chronic illness in teenagers of industrialized countries. From a neurobiological perspective, AN-linked behaviors can be considered an adaptation that permits the endurance of reduced energy supply, involving central and/or peripheral reprograming. The severe weight loss observed in AN patients is accompanied by significant changes in hormones involved in energy balance, feeding behavior, and bone formation, all of which can be replicated in animals models. Increasing evidence suggests that AN could be an addictive behavior disorder, potentially linking defects in the reward mechanism with suppressed food intake, heightened physical activity, and mood disorder. Surprisingly, the plasma levels of ghrelin, an orexigenic hormone that drives food-motivated behavior, are increased. This increase in plasma ghrelin levels seems paradoxical in light of the restrained eating adopted by AN patients, and may rather result from an adaptation to the disease. The aim of this review is to describe the role played by ghrelin in AN focusing on its central vs. peripheral actions. In AN patients and in rodent AN models, chronic food restriction induces profound alterations in the « ghrelin » signaling that leads to the development of inappropriate behaviors like hyperactivity or addiction to food starvation and therefore a greater depletion in energy reserves. The question of a transient insensitivity to ghrelin and/or a potential metabolic reprograming is discussed in regard of new clinical treatments currently investigated.

Rosiglitazone decreases fasting plasma peptide YY3-36 in type 2 diabetic women: a possible role in weight gain?

Rosiglitazone often results in weight gain. We hypothesized that rosiglitazone may modulate circulating levels of ghrelin and peptide YY(3-36) and this modulation may be related to weight-gaining effect of this agent. This study was designed as an open-label, randomized, controlled trial of 3-month duration. Women with newly diagnosed type 2 diabetes were studied. Twenty-eight of the 55 eligible participants were randomly assigned to receive rosiglitazone (4 mg/d). Twenty-seven patients with diabetes matched for age and body mass index served as controls on diet alone. We evaluated the effects of 3 months of rosiglitazone treatment on fasting peptide YY(3-36) and ghrelin levels, and anthropometric measurements. The 3-month administration of rosiglitazone reduced fasting plasma peptide YY(3-36) levels by 25%, the between-group difference was statistically significant. No effect of this thiazolidinedione compound on fasting ghrelin concentrations was observed at the end of study. The ghrelin/body mass index ratio also did not change significantly after treatment. Seventy-five percent of the women with diabetes complained of increased hunger at the end of study. Nevertheless, all subjects exhibited a decrease in fasting PYY levels after 3 months of rosiglitazone therapy, irrespective of the levels of hunger. There was no significant correlation between changes in peptide YY(3-36) and those in anthropometric parameters and insulin sensitivity at the end of the study. Rosiglitazone-induced decrease in fasting peptide YY(3-36) levels may in part contribute to orexigenic and weight-gaining effect of this thiazolidinedione derivative.

Food motivation circuitry hypoactivation related to hedonic and nonhedonic aspects of hunger and satiety in women with active anorexia nervosa and weight-restored women with anorexia nervosa

BACKGROUND

Previous studies have provided evidence of food motivation circuitry dysfunction in individuals with anorexia nervosa. However, methodological limitations present challenges to the development of a cohesive neurobiological model of anorexia nervosa. Our goal was to investigate the neural circuitry of appetite dysregulation across states of hunger and satiety in active and weight-restored phases of anorexia nervosa using robust methodology to advance our understanding of potential neural circuitry abnormalities related to hedonic and nonhedonic state and trait.

METHODS

We scanned women with active anorexia nervosa, weight-restored women with anorexia nervosa and healthy-weight controls on a 3-T Siemens magnetic resonance scanner while they viewed images of high- and low-calorie foods and objects before (premeal) and after (postmeal) eating a 400 kcal meal.

RESULTS

We enrolled 12 women with active disease, 10 weight-restored women with anorexia nervosa and 11 controls in our study. Compared with controls, both weight-restored women and those with active disease demonstrated hypoactivity premeal in the hypothalamus, amygdala and anterior insula in response to high-calorie foods (v. objects). Postmeal, hypoactivation in the anterior insula persisted in women with active disease. Percent signal change in the anterior insula was positively correlated with food stimuli ratings and hedonic and nonhedonic appetite ratings in controls, but not women with active disease.

LIMITATIONS

Our findings are limited by a relatively small sample size, which prevented the use of an analysis of variance model and exploration of interaction effects, although our substantial effect sizes of between-group differences suggest adequate power for our statistical analysis approach. Participants taking psychotropic medications were included.

CONCLUSION

Our data provide evidence of potential state and trait hypoactivations in food motivation regions involved in the assessment of food's reward value and integration of these with interoceptive signalling of one's internal state of well-being, with important relations between brain activity and homeostatic and hedonic aspects of appetite. Our findings give novel evidence of disruption in neurobiological circuits and stress the importance of examining both state and trait characteristics in the investigation of brain phenotypes in individuals with anorexia nervosa.

Fasting plasma peptide YY concentrations are increased in patients with major depression who associate weight loss

BACKGROUND

Many patients with major depression refer a decreased appetite and weight loss among their symptoms. Peptide YY (PYY) and ghrelin belong to the family of peptides of the gut-brain axis implicated in the regulation of appetite and energy metabolism. PYY stimulates a powerful central satiety response and ghrelin increases food intake and weight gain. Brain-derived neurotrophic factor (BDNF) also contributes to the central control of food intake as an anorexigenic factor.

AIM

To study fasting plasma total and acylated ghrelin, plasma PYY and serum BDNF levels in patients with major depression with weight loss as one of their symptoms and compare them with matched healthy controls.

SUBJECTS AND METHODS

Fifteen adult patients, 9 male and 6 female, with recent diagnosis of major depression, and 16 healthy adult subjects, matched by age and anthropometric parameters were studied. All depressed patients referred weight loss and were not under antidepressant therapy. Fasting total PYY, total ghrelin and acylated ghrelin and BDNF were determined.

RESULTS

Fasting total PYY was higher in patients than controls (2.01±0.09 vs 1.29±0.16 pmol/l). There were no differences in fasting total ghrelin, acylated ghrelin or BDNF levels.

CONCLUSIONS

Major depressed patients, with weight loss at diagnosis, showed higher fasting plasma PYY levels that could contribute to their reduced appetite.

Comparison of a high-carbohydrate and high-protein breakfast effect on plasma ghrelin, obestatin, NPY and PYY levels in women with anorexia and bulimia nervosa

Background

The present study investigated plasma levels of gut-brain axis peptides ghrelin, obestatin, NPY and PYY after consumption of a high-carbohydrate (HC) and high-protein (HP) breakfast in patients with anorexia nervosa, bulimia nervosa and in healthy controls. These peptides play an important role in regulation of energy homeostasis and their secretion is disturbed under condition of eating disorders. As various types of consumed macronutrients may induce different plasma hormone responses, so we examined these responses in women patients with eating disorders and compared them with those of healthy controls.

Methods

We examined plasma hormone responses to HC and HP breakfast in patients with AN (n = 14; age: 24.6 ± 1.8 years, BMI: 15.3 ± 0.7), BN (n = 15; age: 23.2 ± 1.7 years, BMI: 20.5 ± 0.9) and healthy controls (n = 14; age: 24.9 ± 1.4 years, BMI: 21.1 ± 0.8). Blood samples were drawn from the cubital vein, the first blood drawn was collected before meal, and then 30, 60, 90, 120 and 150 min after breakfast consumption. Plasma hormone levels were determined by commercially available RIA kits.

Results

Fasting and postprandial plasma obestatin levels were significantly increased in both AN and BN patients, while plasma ghrelin levels were significantly increased in AN patients only. After breakfast consumption, plasma levels of ghrelin and obestatin decreased, although they were still above the range of values of healthy controls. Fasting NPY plasma levels were significantly increased in AN and BN patients and did not change postprandially. Fasting PYY levels were comparable in AN, BN and healthy controls, but postprandially significantly increased after HP breakfast in AN and BN patients. Different reactions to breakfast consumption was found for ghrelin and PYY among investigated groups, while for obestatin and NPY these reactions were similar in all groups.

Conclusions

Significant increase of obestatin and NPY in AN and BN patients may indicate their important role as the markers of eating disorders. Different reactions of ghrelin and PYY to breakfast consumption among groups suggest that role of these hormones in regulation of energy homeostasis can be adjusted in dependence to acute status of eating disorder.

Role of ghrelin in the pathophysiology of eating disorders: implications for pharmacotherapy

Ghrelin is the only known circulating orexigenic hormone. It increases food intake by interacting with hypothalamic and brainstem circuits involved in energy balance, as well as reward-related brain areas. A heightened gut-brain ghrelin axis is an emerging feature of certain eating disorders such as anorexia nervosa and Prader-Willi syndrome. In common obesity, ghrelin levels are lowered, whereas post-meal ghrelin levels remain higher than in lean individuals. Agents that interfere with ghrelin signalling have therapeutic potential for eating disorders, including obesity. However, most of these drugs are only in the preclinical phase of development. Data obtained so far suggest that ghrelin agonists may have potential in the treatment of anorexia nervosa, while ghrelin antagonists seem promising for other eating disorders such as obesity and Prader-Willi syndrome. However, large clinical trials are needed to evaluate the efficacy and safety of these drugs.

Leptin levels are associated with decreased depressive symptoms in women across the weight spectrum, independent of body fat

OBJECTIVE

Leptin is anorexigenic, and levels are markedly decreased in women with low body weight and high in women with obesity. Ghrelin opposes leptin effects on appetite and is negatively associated with body mass index. These appetite-regulating hormones may have opposing effects on mood and stress pathways. Women with anorexia nervosa (AN), hypothalamic amenorrhoea (HA) and obesity are at increased risk of depression and anxiety. It is unknown whether dysregulation of leptin or ghrelin contributes to the development of depression and/or anxiety in these disorders. We investigated the relationship between leptin and ghrelin levels and symptoms of depression, anxiety and perceived stress in women across the weight spectrum.

DESIGN

Cross-sectional.

PATIENTS

64 women: 15 with AN, 12 normal-weight with HA, 17 overweight or obese (OB) and 20 normal-weight in good health (HC).

MEASUREMENTS

Fasting serum leptin and plasma ghrelin levels were measured. Hamilton Rating Scales for Depression (HAM-D) and Anxiety (HAM-A) and the Perceived Stress Scale were administered.

RESULTS

Leptin levels were inversely associated with HAM-D, HAM-A and Perceived Stress scores. The negative relationships between leptin and severity of symptoms of both depression and anxiety remained significant after controlling for body fat or weight. There was no relationship between ghrelin and symptoms of depression or anxiety. Although ghrelin levels were positively associated with the degree of perceived stress, this relationship was not significant after controlling for body fat or weight.

CONCLUSIONS

Leptin may mediate depressive symptoms across the weight spectrum. Further investigation of the role of leptin in modulating mood will be important.