Determinants of plasma adiponectin levels in patients with anorexia nervosa examined before and after weight gain

Modified activity-based anorexia paradigm dampens chronic food restriction-induced hyperadiponectinemia in adolescent female mice

Anorexia nervosa (AN) is a chronic, life-threatening disease with mental and physical components that include excessive weight loss, persistent food restriction, and altered body image. It is sometimes accompanied by hyperactivity, day-night reversal, and amenorrhea. No medications have been approved specific to the treatment of AN, partially due to its unclear etiopathogenesis. Because adiponectin is an appetite-regulating cytokine released by adipose tissue, we hypothesized that it could be useful as a specific biomarker that reflects the disease state of AN, so we developed a modified AN mouse model to test this hypothesis. Twenty-eight 3-week-old female C57BL/6J mice were randomly assigned to the following groups: 1) no intervention; 2) running wheel access; 3) food restriction (FR); and 4) activity-based anorexia (ABA) that included running wheel access plus FR. After a 10-day cage adaptation period, the mice of the FR and ABA groups were given 40% of their baseline food intake until 30% weight reduction (acute FR), then the body weight was maintained for 2.5 weeks (chronic FR). Running wheel activity and the incidence of the estrous cycle were assessed. Spontaneous food restriction and the plasma adiponectin level were evaluated at the end of the acute and chronic FR phases. An increase in running wheel activity was found in the light phase, and amenorrhea was found solely in the ABA group, which indicates that this is a good model of AN. This group showed a slight decrease in spontaneous food intake accompanied with an attenuated level of normally induced plasma adiponectin at the end of the chronic FR phase. These results indicate that the plasma adiponectin level may be a useful candidate biomarker for the status or stage of AN.

Comparison of Adiponectin Levels in Anorexia Nervosa, Bulimia Nervosa, Binge-Eating Disorder, Obesity, Constitutional Thinness, and Healthy Controls: A Network Meta-Analysis

Adiponectin is a protein hormone that is produced and secreted primarily by adipose tissue. The levels of adiponectin in those with eating disorders, obesity, and healthy controls have been extensively studied. However, the general picture of the differences in adiponectin levels across the mentioned conditions is still unclear and fragmented. In this study, we pooled previous studies and performed a network meta-analysis to gain a global picture of comparisons of adiponectin levels across eating disorders, obesity, constitutional thinness, and healthy controls. Electronic databases were searched for anorexia nervosa, avoidant restrictive food intake disorder, binge-eating disorder, bulimia nervosa, healthy controls, night eating syndrome, obesity, and constitutional thinness in studies where adiponectin levels were measured. A total of 4262 participants from 50 published studies were included in the network meta-analysis. Adiponectin levels were significantly higher in participants with anorexia nervosa than in healthy controls (Hedges' g = 0.701, p < 0.001). However, adiponectin levels in constitutionally thin participants were not significantly different from those of healthy controls (Hedges' g = 0.470, p = 0.187). Obesity and binge-eating disorder were associated with significantly lower adiponectin levels compared to those of healthy controls (Hedges' g = -0.852, p < 0.001 and Hedges' g = -0.756, p = 0.024, respectively). The disorders characterized by excessive increases or decreases in BMI were associated with significant changes in adiponectin levels. These results suggest that adiponectin may be an important marker of severely disequilibrated homeostasis, especially in fat, glucose, and bone metabolisms. Nonetheless, an increase in adiponectin may not simply be associated with a decrease in BMI, as constitutional thinness is not associated with a significant increase in adiponectin.

Adiponectin in anorexia nervosa and its modifiers: A meta-regression study

OBJECTIVE

Adiponectin, which is secreted from adipose tissue, is a protein hormone. Although a large body of studies have found that circulating adiponectin levels increase in anorexia nervosa (AN) and caloric restriction, the effect of subtypes of AN and modifiers of adiponectin in AN are not yet known.

METHODS

A systematic search of electronic databases was performed using the search terms "adiponectin," "anorexia nervosa," and "eating disorder" up to January 2021. All studies published in peer-reviewed journals, which included cases and control groups, were selected. The main outcome was the pooled standardized mean difference (SMD) in adiponectin levels between cases and controls, using the random-effects model. Modifiers of SMD were tested via meta-regression. Heterogeneity and publication bias were evaluated.

RESULTS

Thirty-four studies met all eligibility criteria. The total sample of AN participants (Hedges' g = .765, p < .0001), and specifically the binge-eating/purging (Hedges' g = 1.211, p < .00001) and restrictive subtypes (Hedges' g = .913, p < .00001) of AN have increased adiponectin plasma levels compared with healthy controls. Meta-regression determined that insulin, IGF-1, BMI, triglyceride, resistin, glucose, IL-6 levels are significant modifiers of adiponectin levels.

DISCUSSION

Compared with controls, adiponectin levels are higher in AN overall, and specifically in the binge-eating/purging and the restrictive AN subtypes. Many of metabolic parameters of glucose metabolism and pro-inflammatory molecules modify the relationship between AN and adiponectin levels. Adipose tissue is important to maintain metabolic stability.

PUBLIC SIGNIFICANCE

Anorexia nervosa is a psychiatric disorder associated with a severe decrease in body weight and multiple metabolic abnormalities, including an increase in the hormone adiponectin. In this paper, we used meta-analysis, a powerful statistical method, to aggregate data from 34 rigorously selected research reports. This enabled us to understand the value of adiponectin to differentiate clinical subtypes of anorexia nervosa and the relations between adiponectin and other important metabolic parameters.

The association between leptin and weight maintenance outcome in anorexia nervosa

OBJECTIVE

Relapse after weight restoration in anorexia nervosa (AN) is a critical problem. Higher body fat percentage after weight gain has been shown to predict better weight maintenance outcome. Leptin, a fat-derived hormone, has been associated with progress during weight gain, but its association with weight maintenance is unknown. This study aims to determine whether leptin levels after weight restoration in AN are associated with weight maintenance.

METHOD

Participants were 41 women with AN hospitalized for inpatient treatment. Participants were evaluated 2-4 weeks after weight restoration to body mass index (BMI) ≥ 19.5 kg/m² for plasma leptin and body composition. Weight maintenance outcome was defined by whether a participant maintained a BMI of at least 18.5 kg/m² at the end of 1 year following hospital discharge.

RESULTS

Twenty (48.8%) out of 41 patients maintained their weight at 1 year. Percent body fat and leptin were significantly higher in the group who maintained weight (body fat, p = .004, Hedges' g = 0.944; log-leptin, p = .010, Hedges' g = 0.821), but there were no differences in predischarge BMI, duration of illness, and duration of amenorrhea. Using regression modeling, only higher log-leptin (p_Wald = .021) and percent body fat (p_Wald = .010), as well as fat-adjusted leptin (p_Wald = .029), independently predicted weight maintenance at 1 year.

DISCUSSIONS

Our findings suggest that for acutely-weight restored women with AN, higher predischarge leptin measurements are associated with better outcome in the year following treatment. Prospective studies examining leptin as well as other parameters of metabolic health could offer insights into biomarkers that may improve clinical outcomes.

Diagnostic strategies and clinical management of lipodystrophy

Introduction: Lipodystrophy is a heterogeneous group of rare diseases characterized by various degrees of fat loss which leads to serious morbidity due to metabolic abnormalities associated with insulin resistance and subtype-specific clinical features associated with underlying molecular etiology.Areas covered: This article aims to help physicians address challenges in diagnosing and managing lipodystrophy. We systematically reviewed the literature on PubMed and Google Scholar databases to summarize the current knowledge in lipodystrophy management.Expert opinion: Adipose tissue is a highly active endocrine organ that regulates metabolic homeostasis in the human body through a comprehensive communication network with other organ systems such as the central nervous system, liver, digestive system, and the immune system. The adipose tissue is capable of producing and secreting numerous factors with important endocrine functions such as leptin that regulates energy homeostasis. Recent developments in the field have helped to solve some of the mysteries behind lipodystrophy that allowed us to get a better understanding of adipocyte function and differentiation. From a clinical standpoint, physicians who suspect lipodystrophy should distinguish the disease from several others that may present with similar clinical features. It is also important for physicians to carefully interpret clinical features, laboratory, and imaging results before moving to more sophisticated tests and making decisions about therapy.

Adiponectin and resistin in acutely ill and weight-recovered adolescent anorexia nervosa: Association with psychiatric symptoms

Objectives: Anorexia nervosa (AN) is a chronic illness where restriction of food intake results in decreased adipose tissue. The aim of this study was to measure the concentration of adiponectin and resistin in acute and partially weight-recovered anorectic inpatients. The associations of their levels with eating disorder symptoms were also assessed.Methods: A longitudinal study was conducted on 76 adolescent patients (ANG) and 30 age-matched healthy girls (CG). Selected adipokines serum levels, as well as the severity of depressive, obsessive-compulsive and disturbed eating behaviours, were analysed in the group of anorectic patients before (accAN) and after weight gain (recAN) and compared with the CG.Results: The concentration of adiponectin in the accAN was higher than in the CG (P = 0.05) and increased in recAN (P = 0.01). Resistin concentrations were lower in accAN and recAN than in the CG (P = 0.00). A negative correlation between adiponectin and the scores in Yale-Brown Obsessive Compulsive Scale as well as positive between resistin and Beck Depression Inventory were found.Conclusions: In the acute AN, adiponectin and resistin levels are impaired and partial weight recovery fails to normalise them thus we suggest that they can be involved in the chronicity of certain symptoms. The level of adiponectin is associated with obsessive and compulsive symptoms and resistin with depressive symptoms, which indicates their potential contribution to the regulation of emotions and behaviours in AN.

Adipokines, cortisol and cytokine alterations in recent onset anorexia nervosa. A case-control study

INTRODUCTION

Psychological and neuroendocrine alterations are typical characteristics in anorexia nervosa patients. The role of adipokines and cytokines as mediators of body systems' adaptations to the patients' abnormal eating behavior is not well understood. The duration of disease seems to be a determinant of nutritional status and associated hormone changes. We aimed to assess whether alterations in adipokines, cytokines and cortisol do already exist in patients with a recent disease onset by means of a case-control study.

METHODS

Forty-one adolescent female patients on their first-episode and diagnosed with anorexia nervosa, were matched by age and socioeconomic status (SES) (1:1) with healthy girls. Leptin, soluble leptin receptor (sOB-R), adiponectin, cortisol, and the cytokines IL-1β, IL-2, IL-6 and TNF-α were examined.

RESULTS

The results showed reduced leptin and increased sOB-R and cortisol levels in AN patients. Adiponectin was also increased but opposite to the previous biomarkers did not correlate with BMI Z-score. Serum TNF-α and IL-2 showed significantly lower and higher values, respectively, in the AN patients than in the controls. Cortisol showed the strongest correlation with sOB-R (r=0.436; P=0.005).

CONCLUSIONS

Our study confirms previous findings on adipokine and cortisol alterations in AN patients, while overall cytokine results did not show a clear disruption in AN patients with short disease duration. The results highlight the need to disentangle the role of the sOB-R in the interactions between leptin and cortisol secretion.

MECHANISMS IN ENDOCRINOLOGY: Anorexia nervosa and endocrinology: a clinical update

Anorexia nervosa is a syndrome, that is collections of symptoms, which is not defined by its etiology. The severe cases are intractable. The syndrome is associated with multiple, profound endocrine alterations which may be adaptive, reactive or etiologic. Adaptive changes potentially may be inappropriate in clinical settings such as inpatient intensive re-nutrition or in a setting with somatic comorbidity. Electrolyte levels must be closely monitored during the refeeding process, and the need for weight gain must be balanced against potentially fatal refeeding complications. An important focus of clinical research should be to identify biomarkers associated with different stages of weight loss and re-nutrition combined with psychometric data. Besides well-established peripheral endocrine actions, several hormones also are released directly to different brain areas, where they may exert behavioral and psychogenic actions that could offer therapeutic targets. We need reliable biomarkers for predicting outcome and to ensure safe re-nutrition, however, first of all we need them to explore the metabolism in anorexia nervosa to open new avenues with therapeutic targets. A breakthrough in our understanding and treatment of this whimsical disease remains. Considering this, the aim of the present review is to provide an updated overview of the many endocrine changes in a clinical perspective.

Is hypercortisolism in anorexia nervosa detectable using hair samples?

Anorexia nervosa (AN) is a severe mental disorder accompanied by extensive metabolic and endocrine abnormalities. It has been associated with hypercortisolism using short-term measurement methods such as 24 h-urine, saliva, and blood. The aim of this study was to examine whether the proposed hypercortisolism in acutely underweight AN (acAN) is also reflected in a long-term measure: hair cortisol (HCC). To gain further insight, we compared hair cortisol to a well-established classical cortisol measure (24 h-urine; UCC) longitudinally in acAN. Hair samples were collected and analyzed using a LC-MS/MS-based method to provide a monthly cortisol value. We compared HCC in samples of 40 acAN with 40 pairwise age-matched healthy controls (HC) as well as 23 long-term recovered AN participants (recAN) with 23 pairwise age-matched HC (cross-sectional design). In the second part, UCC collected weekly during 14 weeks of weight-restoration therapy in 16 acAN was compared with the (time-corresponding) HCC using linear mixed models and bivariate correlations (longitudinal design). No group differences in HCC occurred comparing acAN and recAN to HC (cross-sectional study). The longitudinal analysis revealed a decrease of UCC but not HCC with weight gain. Furthermore, there was no overall significant association between UCC and HCC. Only in the last four weeks of weight-restoration therapy we found a significant moderate correlation between UCC and HCC. HCC did not reflect the expected hypercortisolism in acAN and did not decrease during short-term weight-restoration. Time-corresponding measurements of UCC and HCC were not consistently associated in our longitudinal analysis of acAN undergoing inpatient treatment. Given the drastic metabolic disturbances in acutely underweight AN our findings could be interpreted as disturbed cortisol incorporation or altered activity of 11-β-HSD-enzymes in the hair follicle.

Mifepristone reduces hypothalamo-pituitary-adrenal axis activation and restores weight loss in rats subjected to dietary restriction and methylphenidate administration

This study evaluates the efficacy of mifepristone on weight restoration in rats subjected to dietary restriction and methylphenidate administration. 25 female rats aged between 9 and 12 months were divided into 2 groups: 5 controls (exposed only to dietary restriction) and 20 rats that were administered 5 mg/kg/d of methylphenidate before meal exposure, for 36 days. Among rats who responded to methylphenidate (weight loss of 15-25%) weeks after its administration, a group of 6 rats continued to receive only methylphenidate ("Met" group), and another group received 10 mg/kg/d of mifepristone in addition to methylphenidate for 18 days ("Met+Mif" group; n = 6). The mean weight of the "Met+Mif" group remained significantly lower when compared to the control group (87.63 ± 2.83% vs 96.29 ± 3.26%; p < 0.001 respectively) but was significantly higher than that of the "Met" group (87.63 ± 2.83% vs. 80.61 ± 3.52%; p < 0.001 respectively). Plasma concentrations of adiponectin and gene expression of its receptors in rats brain were significantly higher in the "Met" group as compared to the "Met+Mif" and control groups (p < 0.01). Accordingly, mifepristone reduces HPA axis activation and restores weight through adipose tissue recovering. It might be considered a promising treatment for anorexia nervosa patients in future studies.

Time course of adiponectin and its relationship to psychological aspects in patients with anorexia nervosa during inpatient treatment

OBJECTIVE

The protein hormone adiponectin promotes metabolic and psychological health. The aim of the study was to track changes in adiponectin levels in response to weight gain and to assess associations between adiponectin and psychological aspects in patients with anorexia nervosa (AN).

METHODS

To investigate if adiponectin levels depend on AN severity, data were assessed from 11 inpatients with a very low body mass index (BMI) and a high chronicity (high severity group; HSS), and nine with less severe symptoms (LSS). During the course of treatment, serum adiponectin concentrations were assessed on a weekly basis along with BMI. Psychological variables (i.e., depression, anxiety, stress, and AN-specific symptoms) were obtained by means of electronic diaries. Longitudinal regressions and correlations were calculated to evaluate the temporal course of adiponectin and its relationship with psychological self-ratings.

RESULTS

At the beginning adiponectin was not increased in HSS patients (p = .56), and only marginally elevated in LSS patients (p = 0.07) compared with controls. In HSS patients, adiponectin increased along with BMI during the first treatment phase (i.e., when the BMI of patients was below 16 kg/m2) and thereafter decreased with further weight gain. In LSS patients, adiponectin was not associated with BMI increase. Furthermore, adiponectin was strongly negatively correlated with psychological self-ratings when the BMI of patients was above 16 kg/m2, i.e., higher levels of adiponectin were related to lower ratings of depression, anxiety, and AN-specific symptoms.

DISCUSSION

The study connects previous varying results by indicating that the course of adiponectin is dependent on BMI and symptom severity. Similarly, associations of adiponectin and psychological health depended on BMI.

The importance of the hypothalamo-pituitary-adrenal axis as a therapeutic target in anorexia nervosa

Anorexia nervosa (AN) is an eating disorder, mainly affecting women, with a lifetime prevalence of about 1%, that can run a chronic course. While an effective pharmacotherapy is lacking, it is hypothesized that the progesterone and type II glucocorticoid receptor antagonist mifepristone (RU486) might be useful, as it is well known that the hypothalamo-pituitary-adrenal axis (HPA) is activated in AN. Even if secondary to the eating disorder, an active HPA axis may contribute to maintaining the neuroendocrine, emotional and behavioral effects observed in AN. More specifically, it is suggested that the HPA axis interacts with limbic structures, including the insular and prefrontal cortices, to uphold the changes in interoceptive and emotional awareness seen in AN. As such, it is proposed that mifepristone (RU486) reverses these effects by acting on these limbic regions. In conclusion, the theoretical efficacy of mifepristone (RU486) in improving symptoms of AN should be tested in randomized clinical trials.

Time Course of Leptin in Patients with Anorexia Nervosa during Inpatient Treatment: Longitudinal Relationships to BMI and Psychological Factors

Background

Leptin, a hormone secreted by adipose tissue, appears to play a major role in the homeostasis of body weight and psychobiological processes associated with anorexia nervosa (AN). However, there is scarce data on its exact influence on this disorder, in particular data over time.

Objective

The present study addresses whether leptin changes during inpatient treatment play a role for treatment outcome and psychological factors in underweight AN patients.

Methods

In order to understand whether leptin’s role differs in relation to AN severity, data were assessed from 11 patients with a very low BMI and a higher chronicity (high severity group; HSS; mean BMI at the beginning of the study = 13.6; mean duration of illness = 5.1 years) vs. nine with less severe symptoms (LSS; mean BMI = 16.2; mean duration of illness = 3.7 years). During the course of treatment, serum leptin concentrations were assessed weekly while weight (BMI) was assessed twice per week. Concomitantly, psychological variables were obtained by means of electronic diaries. Unconditional linear growth models were calculated to evaluate the temporal course of leptin in relation to BMI. For HSS patients, two phases of treatment (BMI < 16 and BMI ≥ 16 kg/m²) were investigated.

Results

Leptin increased significantly with BMI in both groups of patients. For HSS patients, the increase of leptin in the first treatment phase did not predict later increases in BMI. Furthermore, the relationship of leptin and psychological factors was modulated by symptom severity. In HSS patients, higher leptin levels were associated with greater feelings of depression, anxiety, and stress whereas in LSS patients a higher leptin level showed the trend to be associated with lower psychological symptom burden.

Conclusions

Our results suggest that leptin changes are differently associated with weight gain and psychological symptoms depending on the severity of starvation.

Inside out: Bone marrow adipose tissue as a source of circulating adiponectin

The adipocyte-derived hormone adiponectin mediates beneficial cardiometabolic effects, and hypoadiponectinemia is a biomarker for increased metabolic and cardiovascular risk. Indeed, circulating adiponectin decreases in obesity and insulin-resistance, likely because of impaired production from white adipose tissue (WAT). Conversely, lean states such as caloric restriction (CR) are characterized by hyperadiponectinemia, even without increased adiponectin production from WAT. The reasons underlying this paradox have remained elusive, but our recent research suggests that CR-associated hyperadiponectinemia derives from an unexpected source: bone marrow adipose tissue (MAT). Herein, we elaborate on this surprising discovery, including further discussion of potential mechanisms influencing adiponectin production from MAT; additional evidence both for and against our conclusions; and observations suggesting that the relationship between MAT and adiponectin might extend beyond CR. While many questions remain, the burgeoning study of MAT promises to reveal further key insights into MAT biology, both as a source of adiponectin and beyond.

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.

Adiponectin in eating disorders

PURPOSE

To elucidate the possible role of adiponectin, an adipokine secreted by white adipose tissue that plays an important role in the neuromodulation of food intake, in the pathogenesis of eating disorders.

METHODS

A comprehensive review of the available literature via MedLine is done using the term "adiponectin" in association with one of the following terms: "anorexia nervosa", "bulimia nervosa", "binge eating disorder" or "eating disorders".

RESULTS

The majority of studies evaluating serum adiponectin levels in patients with eating disorders show that serum adiponectin levels are increased in patients with anorexia nervosa. After refeeding, adiponectin levels tend to rejoin the levels of healthy individuals. Data concerning serum adiponectin levels in patients with bulimia nervosa show that these levels can be equal, higher or lower than those found in healthy controls and lower than those found in anorexia nervosa patients. Binge eating disorder is accompanied with lower serum adiponectin levels than normal. Adiponectin receptor type 1 seems to be more related to the central pathological effect of adiponectin on eating behavior.

CONCLUSION

The potential role that plays adiponectin in the pathogenesis of eating disorders needs to be elucidated by further studies.

Metabolic dysfunction in anorexia nervosa

SUMMARY

CONTEXT

Anorexia nervosa (AN) is an eating disorder characterized by self-induced energy deficit and low body weight with major consequences for most organ systems and a tendency towards self-perpetuation.

OBJECTIVES

To compare metabolic responses to glucose and exercise in women hospitalized with AN (n = 10) before and after 6-weeks weight gain program and in lean healthy weight women (BMI < 22 kg/m(2)) (n = 7).

MAIN OUTCOMES

Weight, body composition, indirect calorimetry, and response of serum insulin, glucose, adiponectin and leptin to oral glucose (75 g) and to 30-min of cycling at 50 rpm.

RESULTS

Patients with AN had similar lean mass to controls, but had significantly less body fat. Adiponectin was 43% higher (p < 0.01) and leptin 47% lower in AN subjects versus controls (p = 0.04). In response to moderate exercise, fasting glucose increased in AN (p < 0.05), but was unchanged in controls. After glucose ingestion, a trend towards a greater increase in diet-induced thermogenesis was also observed in patients with AN (p = 0.07). Despite a further 6 weeks as in patients, weight was not significantly changed in AN. Similarly, glucose, insulin, leptin or adiponectin were not altered.

CONCLUSIONS

AN patients appear metabolically healthy under resting conditions, but their responses to physiological stressors differed from those of controls. Potential impediments to weight gain should be further investigated to define mechanisms with a view to improving the effectiveness of nutritional management.

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.

The effect of gonadal and adrenal steroid therapy on skeletal health in adolescents and young women with anorexia nervosa

Anorexia nervosa (AN) is characterized by subnormal estrogen and dehydroepiandrosterone (DHEA) levels. We sought to determine whether the combination of DHEA + estrogen/progestin is superior to placebo in preserving skeletal health over 18 months in AN. Females with AN, aged 13 to 27 years, were recruited for participation in this double-blind, placebo-controlled, randomized trial. Ninety-four subjects were randomized, of whom 80 completed baseline assessments and received either study drug (oral micronized DHEA 50 mg + 20 µg ethinyl estradiol/0.1 mg levonorgestrel combined oral contraceptive pill [COC] daily; n = 43) or placebo (n = 37). Serial measurements of areal bone mineral density (aBMD), bone turnover markers, and serum hormone concentrations were obtained. Sixty subjects completed the 18-month trial. Spinal and whole-body aBMD z scores were preserved in the DHEA + COC group, but decreased in the placebo group (comparing trends, P = .008 and P = .001, respectively). Bone turnover markers initially declined in subjects receiving DHEA + COC and then returned to baseline. No differences in body composition, adverse effects of therapy, or alterations in biochemical safety parameters were observed. Combined therapy with DHEA + COC appears to be safe and effective for preventing bone loss in young women with AN, whereas placebo led to decreases in aBMD. Dehydroepiandrosterone + COC may be safely used to preserve bone mass as efforts to reverse the nutritional, psychological, and other hormonal components of AN are implemented.

Adipocytokines, gut hormones and growth factors in anorexia nervosa

Anorexia nervosa is a complex eating disorder of unknown etiology which affects adolescent girls and young women and leads to chronic malnutrition. Clinical manifestations of prolonged semistarvation include a variety of physical features and psychiatric disorders. The study of different biological factors involved in the pathophysiology of anorexia nervosa is an area of active interest. In this review we have described the role of adipocytokines, neurotrophins, peptides of the gastrointestinal system and growth factors in appetite regulation, energy balance and insulin sensitivity in anorexia nervosa patients.

Neuroendocrine dysregulation of food intake in eating disorders

Anorexia nervosa (AN) and bulimia nervosa (BN) are psychiatric disorders characterized by abnormal eating behaviors and imbalance of energy homeostasis. Changes of both central and peripheral neuroendocrine substances involved in the modulation of food intake and energy expenditure have been described in acutely ill patients with eating disorders. This review selectively focuses on the most recent findings supporting abnormal changes in the physiology of some peripheral adipokines and gut-secreted peptides, brain-derived neurotrophic factor and endocannabinoids in patients with AN or BN. Literature data do suggest a dysregulation of these neuroendocrine feeding regulators but, at the moment, they do not allow to establish the state or trait-dependent nature of those aberrations. It has been proposed, although not definitively proved, that neuroendocrine alterations, even when secondary to malnutrition and/or to aberrant eating behaviors, 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. Future studies should clarify whether neuroendocrine alterations are part of the genetically transmitted biological vulnerability to eating disorders.

Modulation of adiponectin and leptin during refeeding of female anorexia nervosa patients

CONTEXT

Several studies assessed adiponectin levels in anorexia nervosa (AN) patients, however, data regarding the dynamics of changes in adiponectin levels during refeeding of these patients is limited and contradicting.

OBJECTIVE

Our objective was to assess adiponectin levels and the distribution of its different isoforms in AN patients before and after long-term refeeding, and to relate them to alterations in body mass index, leptin, insulin sensitivity, and additional endocrine parameters.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a longitudinal controlled study of 38 female adolescent malnourished AN inpatients, with 13 young, lean, healthy women serving as controls. Blood samples were obtained upon admission and thereafter at 1, 3, and 5 months (at target weight).

MAIN OUTCOME MEASURES

Changes in body mass index, leptin, adiponectin, insulin sensitivity, and adiponectin multimeric forms were measured.

RESULTS

At admission, leptin levels of AN patients were significantly lower, whereas insulin sensitivity (assessed by homeostasis model assessment-insulin resistance), adiponectin levels, and the ratio of high molecular weight (HMW) adiponectin to total adiponectin were significantly higher compared with controls. During weight recovery, leptin levels and homeostasis model assessment-insulin resistance increased significantly, whereas adiponectin and HMW adiponectin/total adiponectin ratio decreased significantly, to levels similar to controls. An initial increase in adiponectin levels was observed after 1 month of refeeding. There was no correlation between adiponectin and either T(4) or cortisol levels.

CONCLUSIONS

Our study demonstrates hyperadiponectinemia, increased adiponectin HMW isoform, and increased insulin sensitivity in adolescent AN female patients and reversal of these findings with weight rehabilitation. We hypothesize that increased adiponectin levels may have a protective role in maintaining energy homeostasis during extreme malnourishment.

High adiponectin in chronic liver disease and cholestasis suggests biliary route of adiponectin excretion in vivo

BACKGROUND/AIMS

Models of fatty liver diseases and fibrosis suggest a hepatoprotective effect of adiponectin, an adipocyte-derived hormone with antidiabetic, antiobesity, antiatherogenic and anti-inflammatory effects.

METHODS

We studied adiponectin serum levels in 111 chronic liver disease (CLD) patients and 226 healthy controls and the impact of cholestasis on adiponectin by bile duct ligation experiments in mice.

RESULTS

Adiponectin was significantly elevated in CLD, and correlated with stage of liver cirrhosis, liver cell injury, e.g. aminotransferase activity, and inflammatory markers, but not with liver synthesis capacity, insulin sensitivity (HOMA index) or clinical complications. As patients with biliary liver diseases and cholestasis exhibited the highest adiponectin levels, we experimentally investigated a potential biliary route of adiponectin excretion. Following bile duct ligation in mice adiponectin levels rapidly increased without affecting hepatic adiponectin gene expression. Also, adiponectin was detectable in human bile. High adiponectin concentrations were associated with severe cholangitis and/or cholestasis on liver histology.

CONCLUSIONS

Adiponectin is elevated in chronic liver disease and correlates with inflammation and liver damage. High adiponectin levels after bile duct ligation in mice and in human bile from cholestatic patients suggest that biliary secretion is involved in adiponectin clearance and that adiponectin could serve as a novel marker indicating cholestasis in liver cirrhosis.